3.4 Procedures in dedicated mode and in group transmit mode

04.183GPPMobile radio interface Layer 3 specificationRadio Resource Control (RRC) protocolRelease 1999TS

Procedures described in this sub-clause apply to the dedicated mode and/or the group transmit mode.

Those procedures which are specific for group transmit mode or refer to transitions to the group transmit mode are only applicable for mobile stations supporting VGCS talking.

Direct transition between dedicated mode and group transmit mode is possible in both directions by use of the following procedures:

– Channel assignment procedure;

– Handover procedure;

– Channel mode modify procedure.

3.4.1 SACCH procedures

3.4.1.1 General

In dedicated mode and group transmit mode, the SACCH is used in signalling layer at least for measurement results transmission from the mobile station.

The SACCH has the particularity that continuous transmission must occur in both directions at least on the channel carrying the main signalling link. For that purpose, in the mobile station to network direction, measurement result messages are sent at each possible occasion when nothing else has to be sent (see sub-clause 3.4.1.2). Similarly, SYSTEM INFORMATION TYPE 5, 6 and optionally 5bis and 5ter messages are sent in the network to mobile station direction in UI frames when nothing else has to be sent.

The network may in adddition send MEASUREMENT INFORMATION messages on the SACCH, which may order the MS to use the enhanced measurement report.

In a multislot configuration the SYSTEM INFORMATION TYPE 5, 6 and optionally 5bis, 5ter and MEASUREMENT INFORMATION messages shall be sent on the SACCH associated with the channel carrying the main signalling link.

In a multislot configuration the mobile station shall ignore all messages received on the SACCH(s) that are not associated with the channel carrying the main signalling link.

On a VGCS channel, the network may send additional or alternative system information messages for both mobile stations in group transmit mode and those in group receive mode (see sub-clause 3.4.15.2.1).

A mobile station with extended measurement capabilities which receives EXTENDED MEASUREMENT ORDER (EMO) messages on the SACCH, shall perform and report extended measurements, see sub-clause 3.4.1.3.

The SYSTEM INFORMATION TYPE 5bis message shall be sent if and only if the EXT IND bit in the Neighbour Cell Description information element in both the SYSTEM INFORMATION TYPE 5 and TYPE 5bis messages indicates that each information element only carries part of the BA.

A GSM 900 mobile station which only supports the primary GSM band P-GSM 900 (see 3GPP TS 05.05) may consider the EXT-IND bit in the Neighbour cell description IE in the SYSTEM INFORMATION TYPE 5 message bit as a spare bit, assume that the information element carries the complete BA, and ignore any SYSTEM INFORMATION TYPE 5bis messages.

NOTE: The network should take into account limitations of certain mobile stations to understand SYSTEM INFORMATION TYPE 5ter and TYPE 5bis messages, the EXT-IND bit in the Neighbour cell description, and formats used in the Neighbour cell description information element and Cell Channel Description information element used in SYSTEM INFORMATION messages, see sub-clause 10.5.2.1b, and sub-clause 10.5.2.22.

As specified in 3GPP TS 05.08, problems occurring in the reception of SACCH frames are interpreted as a loss of communication means and appropriate procedures are then triggered as specified in sub-clause 3.4.13.

3.4.1.2 Measurement Report and Enhanced Measurement Report

When in dedicated mode or group transmit mode, the mobile station regularly sends either MEASUREMENT REPORT or ENHANCED MEASUREMENT REPORT messages to the network. These messages contain measurement results about reception characteristics from the current cell and from neighbour cells. The BA (list) which is the initial basis for the measurements is derived from information received on the BCCH in System Information 2 and optionally 2bis and/or 2ter and on the SACCH in System Information 5 and optionally 5bis and/or 5ter. MEASUREMENT INFORMATION and SI2quater messages may add information for the GSM Neighbour Cell List and provide 3G Neighbour Cell list. The Mobile Station shall use ENHANCED MEASUREMENT REPORT messages instead of MEASUREMENT REPORT messages if that is indicated by the parameter REPORT_TYPE and if at least one BSIC is allocated to each BA (list) frequency. For report with the MEASUREMENT REPORT message, reporting is performed on two separate lists: the BA (list) and the 3G Neighbour Cell List (for a multi-RAT MS). For report with the ENHANCED MEASUREMENT REPORT message, reporting is performed on the Neighbour Cell List (defined in sub-clause 3.4.1.2.1.3).

In addition, the MS which implements ECSD options shall use fast inband procedure for downlink quality reporting if the use of such procedure has been ordered by the BSC.

When the information is received in more than one message the mobile station shall only combine information relating to the BA (list) from messages received on the same channel and indicating the same value of the BCCH allocation sequence number (BA_IND) without any message indicating a different value of BA_IND received in between. If neighbour cell information for the serving cell is not available, the mobile station indicates this in the MEASUREMENT REPORT message. These measurement results are obtained as specified in 3GPP TS 05.08.

These messages are sent on the slow ACCH, in unacknowledged mode.

If no other message is scheduled on the SACCH at the instant when a layer 2 frame is due to be sent, then the mobile station shall send a MEASUREMENT REPORT message or an ENHANCED MEASUREMENT REPORT or an extended measurement report message (see sub-clause 3.4.1.3) in that frame. The interval between two successive layer 2 frames containing messages for measurement reporting shall not exceed one layer 2 frame.

3.4.1.2.1 Parameters for Measurements and Reporting

Parameters from the Measurement Information, SI2quater or PSI3quater messages allow to build lists which are used for Measurement reporting and Enhanced Measurement reporting.

A full set/all instances of MEASUREMENT INFORMATION (respectively: SI2quater) messages is defined by a number of different instances indicated by the parameter MI_COUNT (respectively SI2quater_COUNT). Two different instances of MEASUREMENT INFORMATION (respectively: SI2quater) messages are two MEASUREMENT INFORMATION (respectively: SI2quater) messages with different MI_INDEX (respectively: SI2quater_INDEX) parameter values.

In Idle mode a multi-RAT MS camping on BCCH shall read and decode a full set of SI2quater messages to form a 3G Neighbour Cell list (each instance can be used as received). When the 3G_BA_IND parameter is changed in idle mode, the MS shall re-read all instances and rebuild the 3G Neighbour Cell list. A multi-RAT MS camping on PBCCH shall construct the 3G Neighbour Cell list from PSI3quater messages, see 3GPP TS 04.60. This list (either from SI2quater or from PSI3quater) shall then be used for reporting when the MS enters dedicated mode, until the MS has received a given number of instances of MEASUREMENT INFORMATION messages that contain 3G Neighbour Cell Description. This number of instances is defined by the 3G-WAIT parameter. When the 3G_BA_IND parameter is changed when on SACCH, the MS shall also re-read all instances, rebuild the 3G Neighbour Cell list, and use the new list for reporting based on the parameter 3G-Wait.

For the GSM neighbour cell list the MS shall combine the BA (list) received in SI5/SI5bis/SI5ter with the BSIC list received in one or more instances of the MEASUREMENT INFORMATION message with the same BA_IND value as the BA (list). When the BA_IND is changed the MS shall rebuild the combined list (the BSIC list shall also be rebuilt). If BSICs received from the SI2quater message are used (see sub-clause 3.4.1.2.1.2), the GSM neighbour cell list is also defined by the combination of the BA (list) received in SI2/SI2bis/SI2ter and the BSIC list from the SI2quater. When the BA_IND is changed the MS shall rebuild the combined list (the BSIC list shall also be rebuilt).

The MS shall combine the BA (list) with the Real Time Differences parameters received in the MEASUREMENT INFORMATION message with the same BA_IND value as the BA (list). When the BA_IND is changed the MS shall re-read the Real Time Differences parameters in all instances.

The MS shall combine the Neighbour Cell list with the REP_PRIORITY parameters received in the MEASUREMENT INFORMATION message with the same BA_IND and 3G_BA_IND values respectively as the Neighbour Cell list. When the BA_IND or 3G_BA_IND are changed the MS shall re-read the REP_PRIORITY parameters in all instances.

If the MP_CHANGE_MARK parameter is changed, the MS shall re-read the Real Time differences, REP_PRIORITY, Measurement Parameters and 3G Measurement Parameters in all instances. The MS shall start using the parameters as soon as they have been received. In the case that not all the parameters have been received in a full set of instances, then the default values shall be used. If different values occur for the same parameter in different instances of a message, the instance with the highest index shall be used.

3.4.1.2.1.1 Deriving the 3G Neighbour Cell list from the 3G Neighbour Cell Description sent on BCCH or on SACCH:

This applies only to a multi-RAT MS. One or more instances of the Measurement Information message or SI2quater message may provide 3G Neighbour Cell Description information. This is used to build the 3G Neighbour Cell list. The 3G Neighbour Cell list may contain up to 96 3G Neighbour Cells and/or UTRAN frequencies for RSSI reporting.

Building of the 3G Neighbour Cell list:

Each 3G Neighbour Cell Description received is added to the 3G Neighbour Cell list, starting with the index equal to the parameter Index_Start_3G. If this parameter is not present then the value 0 shall be used.

For each 3G Neighbour Cell Description, the cells / UTRAN frequencies are indexed in the following order:

1) UTRAN FDD cells / UTRAN FDD frequencies: FDD ARFCNs are indexed in the order of occurrence in the 3G Neighbour Cell description. For each FDD ARFCN indicating UTRAN FDD cells, the cells are indexed in the order of increasing values of the decoded FDD_CELL_INFORMATION parameters.

2) UTRAN TDD cells / UTRAN TDD frequencies: TDD ARFCNs are indexed in the order of occurrence in the 3G Neighbour Cell description. For each TDD ARFCN indicating UTRAN TDD cells, the cells are indexed in the order of increasing values of the decoded TDD_CELL_INFORMATION parameters.

3) CDMA 2000 cells: The cells are indexed in the order of occurrence in the 3G Neighbour Cell description.

If a 3G Neighbour Cell Description includes non-supported frequencies or Radio Access Technologies, this shall not be considered as an error; indices in the 3G Neighbour Cell list shall be incremented accordingly. If more than one cell / UTRAN frequency with the same index in the 3G Neighbour Cell list are provided by different instances of 3G Neighbour Cell Descriptions, the cell / UTRAN frequency from the message instance with the highest index shall be used. In case the same 3G Cell / UTRAN frequency occurs more than once in the resulting 3G Neighbour Cell list, each occurrence shall be assigned an index but only the cell / UTRAN frequency with the highest index in the 3G Neighbour Cell list shall be referred to in measurement reports. If a cell / UTRAN frequency is provided for an index higher than 95 in the 3G Neighbour Cell list, this shall not be considered as an error; the cell / UTRAN frequency shall not be included in the 3G Neighbour Cell list.

The MS behaviour is not specified if the number of 3G frequencies or cells exceeds the MS monitoring capabilities as defined in 3GPP TS 05.08.

3.4.1.2.1.2 Deriving the GSM Neighbour Cell list from the BSICs and the BA (list)

One or more instances of the Measurement Information message may provide BSIC information. This is used to build the GSM Neighbour Cell list. The GSM Neighbour Cell list may contain up to 96 Neighbour Cells.

The BSICs are associated to the frequencies in the BA (list) with the same BA_IND value. The BSICs may be received before the corresponding BA (list). The first BSIC in each instance applies to the frequency in the BA (list) referenced by the parameter BA_Index_Start_BSIC. For each successive BSIC, one bit indicates if the BSIC applies to the same frequency as the previous BSIC or to the next frequency in the BA (list), as defined in sub-clause 9.1.54, Measurement Information message.

If GPRS BSIC Description is provided in the SI2quater message (see sub-clause 3.4.1.2.1.6), it should be saved and used by a non-GPRS mobile station as initial BSIC information in connected mode.

3.4.1.2.1.3 Deriving the Neighbour Cell list from the GSM Neighbour Cell list and the 3G Neighbour Cell list

For report with the ENHANCED MEASUREMENT REPORT message, the Neighbour Cell list is the concatenation of the GSM Neighbour Cell list and the 3G Neighbour Cell list (if any). In this concatenation the value of the parameter Absolute_Index_Start_EMR is added to the 3G Neighbour Cell list indices. The Neighbour Cell list may contain up to 96 Neighbour Cells. If the same index occurs for a GSM Cell and a 3G Cell, the GSM Cell shall be used.

NOTE: For report with the MEASUREMENT REPORT MESSAGE, the concatenated list is not used. Instead, the two lists are used separately, as defined in sub-clause 10.5.2.20, ‘Measurement Results’.

3.4.1.2.1.4 Real Time Differences

One or more instances of the Measurement Information message may provide Real Time Difference information. This is used to build the Real Time Difference list. The mobile station may use Real Time Difference parameters before receiving the BSIC information defined in sub-clause 3.4.1.2. The Real Time Difference list may contain up to 96 Real Time Difference parameters.

The Real Time Difference list is associated with the BA (list) having the same BA_IND value. Each frequency in the BA (list) may be associated to 0, 1 or more Real Time Difference parameters. The Real Time Difference parameters may be received before the corresponding BA (list). The parameter BA_Index_Start_RTD in each structure indicates the index of the frequency in the BA (list) to be taken as a starting reference. A sub-structure is included for each frequency referenced. Each of those sub-structures indicates if 0, 1 or more RTD parameters are present for this frequency. If a frequency in the BA (list) is not provided with Real Time Difference information by any of the message instances with correct BA_IND, it shall be assumed that no information is available for that frequency, see sub-clause 9.1.54. If more than 96 Real Time Difference parameters are provided for the Real Time Difference list, this shall not be considered as an error.

If GPRS Real Time Differences Description is provided in the SI2quater message (see sub-clause 3.4.1.2.1.6), it may also be used by a non-GPRS mobile station in Idle mode.

The MS is not required to take into account more RTDs than cells on the frequency.

3.4.1.2.1.5 Report Priority Description

Report Priority information can be received in one instance of the MEASUREMENT INFORMATION message. The Report Priority information is associated with the Neighbour Cell list (see sub-clause 3.4.1.2.1.3) having the same BA_IND value and 3G_BA_IND value. Each REP_PRIORITY bit of this field relates to indices of the Neighbour Cell list, starting with index 0. The Report Priority information may be received before the corresponding Neighbour Cell list.

Indices exceeding the value 95 shall be ignored. If there are fewer indices than the number of Neighbour Cells, the value 0 shall be assumed for the missing bits.

3.4.1.2.1.6 GPRS Parameters

A set of information may be received in the SI2quater message to be used for GPRS neighbour cell measurement and (NC) Measurement reporting when the cell has no PBCCH allocated, see 3GPP TS 04.60 sub-clause 5.6. This information comprises GPRS Report Priority Description, GPRS BSIC Description, GPRS Real Time Differences Description, GPRS Measurement Parameters, GPRS 3G Measurement Parameters and NC Measurement Parameters. The use of the parameters is similar to parameters without the term "GPRS".

3.4.1.2.1.7 The 3G Cell Reselection list

This applies only to a multi-RAT MS. One or more instances of the SI2quater and/or SI2ter messages may provide 3G Cells. If 3G Cells are provided in both of these messages, the union of the cells shall be included in the 3G Cell Reselection list. The 3G Cell Reselection list may contain up to 96 3G Cells. 3G Cells not provided explicitly in the SI2ter message or in the SI2quater message (frequencies on their own) are not included in these 96 cells. Up to 8 frequencies on their own, can be added to these 96 cells.

The MS behaviour is not specified if the number of 3G frequencies or cells exceeds the MS monitoring capabilities as defined in 3GPP TS 05.08.

3.4.1.3 Extended measurement report $(MAFA)$

Only applicable to mobile stations which support extended measurement.

When in dedicated mode or group transmit mode, a mobile station may receive an EXTENDED MEASUREMENT ORDER (EMO) message, from the network. The mobile station shall then, as defined in 3GPP TS 05.08, for one reporting period perform measurements on the frequencies specified by this EMO message. The mobile station shall thereafter send an EXTENDED MEASUREMENT REPORT message. This message contains the measurement results as defined in 3GPP TS 05.08.

If the mobile station has not started to send its EXTENDED MEASUREMENT REPORT within 10 s after the reception of the EMO message, no EXTENDED MEASUREMENT REPORT shall be sent. The mobile station shall after a successful channel change abort any pending measurements or reporting related to an EMO message received on the old channel.

If a mobile station receives an EMO message indicating the same value of the sequence code as an EMO message received earlier on the same channel without having received any EMO message indicating a different value of the sequence code in between, that EMO message shall be ignored. If the mobile station, before the reporting related to an EMO message has started, receives a new EMO message with a different value of the sequence code, any pending measurements or reporting related to the earlier EMO message shall be aborted and the new message treated.

The EMO message and the EXTENDED MEASUREMENT REPORT message are sent on the SACCH, in unacknowledged mode.

3.4.2 Transfer of messages and link layer service provision

When in dedicated mode or in group transmit mode, upper layers can send messages in multiframe or unacknowledged mode on SAPI 0.

Moreover, but only when in dedicated mode, upper layers have access to the full link layer services for SAPIs other than 0, with the exception of the error indication and local end release that are directly treated by the RR sublayer, as specified in particular places of clause 3.

3.4.3 Channel assignment procedure

In dedicated mode, dual transfer mode or in group transmit mode, an intracell change of channel can be requested by upper layers for changing the channel type, or decided by the RR sublayer, e.g. for an internal handover. This change may be performed through the dedicated channel assignment procedure.

The purpose of the channel assignment procedure is to completely modify the physical channel configuration of the mobile station without frequency redefinition or change in synchronization while staying in the same cell.

This procedure shall not be used for changing between dependent configurations, i.e. those sharing Radio Resource for the main signalling link. An example of dependent channels is a full rate channel and one of the corresponding half rate channels. In multislot operation however, it is allowed to use the same timeslots before and after the assignment, as long as the main signalling link has been changed. The only procedures provided for changing between dependent configurations for the main signalling link are the additional assignment and the partial release procedures.

The channel assignment procedure happens only in dedicated mode, dual transfer mode and in group transmit mode. This procedure cannot be used in the idle mode; in this case the immediate assignment procedure is used.

The channel assignment procedure includes:

– the suspension of normal operation except for RR management (layer 3);

– the release of the main signalling link, and of the other data links as defined in sub-clause 3.1.4, the disconnection of TCHs if any, and the release of packet resources, if in dual transfer mode;

– the deactivation of previously assigned channels (layer 1);

– the activation of the new channels and their connection if applicable;

– The triggering of the establishment of the data link connections for SAPI = 0.

The channel assignment procedure is always initiated by the network.

3.4.3.1 Channel assignment initiation

The network initiates the channel assignment procedure by sending an ASSIGNMENT COMMAND message to the mobile station on the main signalling link. It then starts timer T3107.

NOTE: The network should take into account limitations of certain mobile stations to understand formats used in the Frequency List IE and Cell Channel Description IE used in the ASSIGNMENT COMMAND message, see sub-clause 10.5.2.13 and sub-clause 10.5.2.1b.

When sending this message on the network side, and when receiving it on the mobile station side, all transmission of signalling layer messages except for those RR messages needed for this procedure and for abnormal cases is suspended until resumption is indicated. These RR messages can be deduced from sub-clause 3.4.3 and sub-clause 8.8 Radio Resource management.

Upon receipt of the ASSIGNMENT COMMAND message, the mobile station initiates a local end release of link layer connections and packet resources, if in dual transfer mode, disconnects the physical channels, commands the switching to the assigned channels and initiates the establishment of lower layer connections (this includes the activation of the channels, their connection and the establishment of the main signalling links).

The ASSIGNMENT COMMAND message contains the description of the new configuration, including for the multislot configuration and the TCH/H + TCH/H + ACCHs configuration, the exact ACCHs to be used and a power command. The power level defined in this power command shall be used by the mobile station for the initial power on the new channel(s). It shall not affect the power used on the old channel(s). The message may also contain definitions of the channel mode to be applied for one or several channel sets. If a previously undefined channel set is defined by the ASSIGNMENT COMMAND message, a definition of the channel mode for the new channel set shall be included in the message.

If the channel mode to be applied corresponds to an initial assignment of a multi-rate speech codec, the ASSIGNMENT COMMAND message shall contain the MultiRate Configuration IE, which defines the set of codec modes and related information to use on the new channel.

If the assignment is related to an intra-cell handover from a multi-rate speech codec to a multi-rate speech codec, the MultiRate Configuration IE shall be included in the case of full rate to half rate. If not included in this case, the mobile station shall behave as if the MultiRate Configuration IE was inconsistent. If not included in other cases, the MS shall use on the new channel the AMR configuration it was using on the old channel when it received the ASSIGNMENT COMMAND message.

An ASSIGNMENT COMMAND message may indicate a frequency change in progress, with a starting time and possibly alternative channel descriptions.

In the case of the reception of an ASSIGNMENT COMMAND message which contains only the description of a channel to be used after the starting time, the mobile station shall wait up to the starting time before accessing the channel. If the starting time has already elapsed, the mobile shall access the channel as an immediate reaction to the reception of the message (see 3GPP TS 05.10 for the timing constraints).

If the message contains both the description of a channel to be used after the indicated time and of a channel to be used before, the mobile station accesses a channel as an immediate reaction to the reception of the message. If the moment the mobile station is ready to access is before the indicated time, the mobile station accesses the channels described for before the starting time. The mobile station then changes to the channel described for after the starting time at the indicated time. New parameters can be frequency list, MAIO and HSN. Other parameters describing the allocated channels must be identical to the parameters described for before the starting time. If the moment the mobile station is ready to access is after the starting time, the mobile station accesses the channel described for after the starting time.

If frequency hopping is applied, the cell allocation if present in the message is used to decode the mobile allocation. If the cell allocation is not included, the mobile station uses its current cell allocation, the current CA is the last CA received on the BCCH. Afterward, the current CA may be changed by some messages sent on the main signalling link containing a CA (the possible messages are: ASSIGNMENT COMMAND, HANDOVER COMMAND and FREQUENCY REDEFINITION). Note that there are cases in which the current CA is undefined, see sub-clause 3.4.3.3.

The ASSIGNMENT COMMAND message may contain a cipher mode setting IE. In that case, this ciphering mode has to be applied on the new channel. If no such information is present, the ciphering mode is the same as on the previous channel. In either case the ciphering key shall not be changed. The ASSIGNMENT COMMAND message shall not contain a cipher mode setting IE that indicates "start ciphering" unless a CIPHERING MODE COMMAND message has been transmitted earlier in the RR connection: if such an ASSIGNMENT COMMAND message is received it shall be regarded as erroneous, an ASSIGNMENT FAILURE with cause "Protocol error unspecified" message shall be returned immediately, and no further action taken.

In a voice group call, the ASSIGNMENT COMMAND message may contain a VGCS target mode information element defining which RR mode is to be used on the new channel (i.e. dedicated mode or group transmit mode). If this information element is not present, the mode shall be assumed to be the same as on the previous channel. The VGCS target mode information element shall also indicate the group cipher key number for the group cipher key to be used on the new channel or if the new channel is non ciphered. If the information element is not present, the ciphering mode and group cipher key shall be the same as on the previous channel. Mobile stations not supporting VGCS talking shall ignore the ASSIGNMENT COMMAND message if the VGCS target mode information element is included in the message and shall send an RR STATUS message to the network with cause #96. If a VGCS target mode information element and a cipher mode setting information element is included in the same message, then a mobile station supporting VGCS talking mobile shall regard the ASSIGNMENT COMMAND message as erroneous, an ASSIGNMENT FAILURE message with cause "Protocol error unspecified" shall be returned immediately, and no further action taken.

3.4.3.2 Assignment completion

After the main signalling link is successfully established, the mobile station returns an ASSIGNMENT COMPLETE message, specifying cause "normal event", to the network on the main DCCH.

The sending of this message on the mobile station side and its receipt on the network side allow the resumption of the transmission of signalling layer messages other than those belonging to RR management.

At the receipt of the ASSIGNMENT COMPLETE message, the network releases the previously allocated resources and stops timer T3107.

3.4.3.3 Abnormal cases

If the mobile station has no current CA and if it needs a CA to analyse the ASSIGNMENT COMMAND message, it stays on the current channel(s) and sends an ASSIGNMENT FAILURE message with cause "no cell allocation available".

If the ASSIGNMENT COMMAND message instructs the mobile station to use a Channel Description or Mode that it does not support, or if the Channel Mode to use is not defined for all channel sets, then the mobile station shall return an ASSIGNMENT FAILURE message with cause "channel mode unacceptable", and the mobile station shall remain on the current channel(s) and uses the old Channel Description or Channel Mode(s).

If the mobile station receives an ASSIGNMENT COMMAND message containing an inconsistent MultiRate Configuration IE, then the mobile station shall return an ASSIGNMENT FAILURE message with cause "channel mode unacceptable", and the mobile station shall remain on the current channel(s) and uses the old Channel Description or Channel Mode(s).

The MultiRate Configuration IE shall be considered as inconsistent by the MS if:

– the active set does not include any codec mode or the active set includes more than four codec modes; or

– one or more codec modes of the active codec set are not supported by the assigned channel; or

– the threshold and hysteresis values are not set according to requirements given in 3GPP TS 05.09.

If during the initial assignment of the multirate speech the mobile station receives an ASSIGNMENT COMMAND message and the MultiRate Configuration IE is not present, then the mobile station shall return an ASSIGNMENT FAILURE message with cause "channel mode unacceptable", and the mobile station shall remain on the current channel(s) and uses the old Channel Description or Channel Mode(s).

If the ASSIGNMENT COMMAND message instructs the mobile station to use a frequency that it is not capable of, then the mobile station shall return an ASSIGNMENT FAILURE message with cause "frequency not implemented", and the mobile station shall remain on the current channel(s).

If the mobile station receives an ASSIGNMENT COMMAND message with a Frequency List IE indicating frequencies that are not all in one band, then the mobile station shall stay on the current channel(s) and send an ASSIGNMENT FAILURE message with cause "frequency not implemented". If the mobile station receives an ASSIGNMENT COMMAND message with a Mobile Allocation IE indexing frequencies that are not all in one band, then the mobile station shall stay on the current channel(s) and send an ASSIGNMENT FAILURE message with cause "frequency not implemented".

NOTE: An ASSIGNMENT COMMAND message sent to a multi band mobile station shall not be considered invalid because it indicates frequencies that are all in a different frequency band to that of the current channel.

On the mobile station side, if a lower layer failure happens on the new channel before the ASSIGNMENT COMPLETE message has been sent, the mobile station deactivates the new channels, reactivates the old channels, reconnects the TCHs if any and triggers the establishment of the main signalling link. It then sends a ASSIGNMENT FAILURE message, cause "protocol error unspecified" on the main DCCH and resumes the normal operation, as if no assignment attempt had occurred. The operational parameters (e.g. ciphering mode) when returning on the old channel are those applied before the procedure.

When receiving the ASSIGNMENT FAILURE message, the network stops T3107.

If a lower layer failure happens while attempting to connect back to the old channels, the radio link failure procedure is applied (see sub-clause 3.4.13.2 for dedicated mode and sub-clause 3.4.13.5 for group transmit mode).

On the network side, if timer T3107 elapses before either the ASSIGNMENT COMPLETE message has been received on the new channels or an ASSIGNMENT FAILURE message is received on the old channels, the old channels and the new channels are released if they both were dedicated channels and, unless the mobile station has re-established the call, all contexts related to the connections with that mobile station are cleared. If one of the channels was a VGCS channel, it shall be maintained and the uplink shall be set free. If both channels were VGCS channels, the network shall maintain one of the channels and the uplink shall be set free.

On the network side, lower layer failure occurring on the old channels after the sending of the ASSIGNMENT COMMAND message are ignored. Lower layer failures occurring after the receipt of the SABM Frame on the new main signalling link are treated following the general rules (see sub-clause 3.5.2).

3.4.4 Handover procedure

In dedicated mode, dual transfer mode or group transmit mode, an intercell or intracell change of channel(s) can be requested by the network RR sublayer. This change may be performed through the handover procedure.

NOTE: The decision to do a handover and the choice of the new cell is out of the scope of the present document.

The purpose of the handover procedure is to completely modify the channels allocated to the mobile station e.g. when the cell is changed. A change in the channel configuration nature is possible. This procedure is used only while in dedicated mode, dual transfer mode or group transmit mode.

The handover procedure is also used by Location Services as described in 3GPP TS 03.71.

The handover procedure shall not be used for changing between dependent configurations (see sub-clause 3.4.3). An exception to this is when the handover procedure is used by Location Services. In this case the mobile may be commanded to attempt a handover to the same channel as currently assigned to the MS. The MS shall attempt to perform a handover to this unchanged channel, which includes the transmission of access bursts.

The handover procedure includes:

– The suspension of normal operation except for RR management (layer 3).

– The disconnection of the main signalling link, and of the other links via local end release (layer 2), and the disconnection of the TCH(s) if any.

– The abortion of the packet resources (see 3GPP TS 04.60), if in class A mode of operation.

– The disconnection and the deactivation of previously assigned channels and their release (layer 1).

– The activation of the new channels, and their connection if applicable.

– The triggering of the establishment of data link connection for SAPI = 0 on the new channels.

The handover procedure is always initiated by the network.

3.4.4.1 Handover initiation

The network initiates the handover procedure by sending a HANDOVER COMMAND message to the mobile station on the main DCCH. It then starts timer T3103.

If the HANDOVER COMMAND message refers to a cell to which the mobile station is not synchronised to, this shall not be considered as an error (see 3GPP TS 05.08).

NOTE 1: The network should take into account limitations of certain mobile stations to understand formats used in the Frequency List IE, Frequency Short List IE, and Cell Channel Description IE used in the HANDOVER COMMAND message, see sub-clause 10.5.2.13, sub-clause 10.5.2.14, and sub-clause 10.5.2.1b.

When sending this message on the network side, and when receiving it on the mobile station side, all transmission of signalling layer messages except for those RR messages needed for this procedure and for abnormal cases, is suspended until resuming is indicated. These RR messages can be deduced from sub-clause 3.4.3 and sub-clause 8.5.1.

Upon receipt of the HANDOVER COMMAND message, the mobile station initiates, as described in sub-clause 3.1.4, the release of link layer connections, disconnects the physical channels (including the packet resources, if in class A mode of operation), commands the switching to the assigned channels and initiates the establishment of lower layer connections (this includes the activation of the channels, their connection and the establishment of the data links).

The HANDOVER COMMAND message contains:

– The characteristics of the new channels, including for the multislot configuration and the TCH/H + TCH/H + ACCHs configuration the exact ACCHs to be used. The message may also contain definitions of the channel mode to be applied for one or several channel sets. If a previously undefined channel set is defined by the HANDOVER COMMAND message, a definition of the channel mode for the new channel set shall be included in the message.

– The characteristics of the new cell that are necessary to successfully communicate (e.g. frequency list in the case of slow frequency hopping), including the data that allows the mobile station to use the pre-knowledge about synchronization it acquires by the measurement process (i.e. BSIC + BCCH frequency).

– A power command (see 3GPP TS 05.08). The power level defined in this power command shall be used by the mobile station for the initial power on the new channel(s). It shall not affect the power used on the old channel(s).

– An indication of the physical channel establishment procedure to be used.

– A handover reference, used as specified in the following sub-clause. The choice of the handover reference by the network is out of the scope of the present document and left to the manufacturers.

– Optionally a timing advance to be used on the new cell.

– Optionally a cipher mode setting. In that case, this ciphering mode has to be applied on the new channel. If no such information is present, the ciphering mode is the same as on the previous channel. In either case the ciphering key shall not be changed. In case of 2G to 2G handover, the HANDOVER COMMAND message shall not contain a cipher mode setting IE that indicates "start ciphering" unless a CIPHERING MODE COMMAND message has been transmitted previously in this instance of the dedicated mode: if such a HANDOVER COMMAND message is received it shall be regarded as erroneous, a HANDOVER FAILURE message with cause "Protocol error unspecified" shall be returned immediately, and no further action taken. In the case of UTRAN to GSM handover, the HANDOVER COMMAND message, which is sent transparently via RNC from BSS to the mobile station, shall always contain the cipher mode setting IE to indicate the ciphering mode to be used in GSM. In the case of CDMA2000 to GSM handover, the HANDOVER COMMAND message, which is sent transparently via RNC from BSS to the mobile station, shall always contain the cipher mode setting IE.

– Optionally, in a voice group call, a VGCS target mode information element defining which RR mode is to be used on the new channel (i.e. dedicated mode or group transmit mode). If this information element is not present, the mode shall be assumed to be the same as on the previous channel. The VGCS target mode information element shall also indicate the group cipher key number for the group cipher key to be used on the new channel or if the new channel is non ciphered. If the information element is not present, the ciphering mode and ciphering key shall be the same as on the previous channel. Mobile stations not supporting VGCS talking shall ignore the HANDOVER COMMAND message if the VGCS target mode information element is included in the message and shall send an RR STATUS message to the network with cause #96. If a VGCS target mode information element and a cipher mode setting information element is included in the same message, then a mobile station supporting VGCS talking shall regard the HANDOVER COMMAND message as erroneous, an HANDOVER FAILURE message with cause "Protocol error unspecified" shall be returned immediately, and no further action taken.

– Optionally, when the channel mode indicates that a multi-rate speech codec must be applied, the MultiRateconfiguration to be used in the new cell. The MultiRate Configuration IE defines the set of codec mode and related information to use after the handover. When accessing the new channel, the mobile station shall use for the Initial Codec Mode the mode specified in the MultiRate Configuration IE, if present, or apply by default the implicit rule defined in 3GPP TS 05.09.

In addition, a HANDOVER COMMAND message may indicate a frequency change in progress, with a starting time and possibly alternative channel descriptions.

In the case of the reception of a HANDOVER COMMAND message which contains only the description of a channel to be used after the starting time, the mobile station shall wait up to the starting time before accessing the channel. If the starting time has already elapsed, the mobile shall access the channel as an immediate reaction to the reception of the message (see 3GPP TS 05.10 for the timing constraints).

In the case of a handover towards a GSM cell to which the mobile station is not synchronised to and in the case of an intersystem handover to GSM, at the reception of a HANDOVER COMMAND message which contains only the description of a channel to be used after the starting time, the mobile station shall wait up to the starting time before accessing the new channel. If the starting time has already elapsed, the mobile shall access the new channel as an immediate reaction to the reception of the message (see 3GPP TS 05.10 for the timing constraints). Between the reception of the HANDOVER COMMAND and the starting time there is no requirement for the mobile station to receive or transmit on the old channel.

NOTE 2: This case may result to a long interruption and should not be used.

If the message contains both the description of a channel to be used after the indicated time and of a channel to be used before, the mobile station accesses a channel as an immediate reaction to the reception of the message. If the moment the mobile station is ready to access is before the indicated time, the mobile station accesses the channels described for before the starting time. The mobile station then changes to the channel described for after the starting time at the indicated time. New parameters can be frequency list, MAIO and HSN. Other parameters describing the allocated channels must be identical to the parameters described for before the starting time. If the moment the mobile station is ready to access is after the starting time, the mobile station accesses the channel described for after the starting time.

If the channel mode indicates that a multi-rate speech codec must be applied, and the MultiRateConfiguration IE is not included in the HANDOVER COMMAND message, then the mobile station shall use on the new channel the AMR configuration it was using on the old channel when it received the HANDOVER COMMAND message. The MultiRate Configuration IE shall be included in the case of full rate channel to half rate channel handover. If not included in this case, the mobile station shall behave as if the MultiRate Configuration IE was inconsistent.

3.4.4.2 Physical channel establishment

Four procedures are defined. The support of three of them is mandatory in the mobile station. The pseudo‑synchronization case is optional in the mobile station. A pseudo-synchronized handover can be commanded only to a mobile station that can support it, as indicated in the classmark.

3.4.4.2.1 Finely synchronized cell case

If the mobile station knows that the timing advance with the new cell is not out of range, i.e. smaller than or equal to the maximum timing advance that can be coded as specified in 3GPP TS 04.04, or if the new cell does accept out of range timing advance as indicated in the HANDOVER COMMAND message, the mobile station proceeds as follows.

After having switched to the assigned channels, the mobile station sends four times the HANDOVER ACCESS message in four successive layer 1 frames on the main DCCH. This message is sent in an access burst. Its content is reduced to the handover reference information element. The transmission of these four messages is optional if so indicated by the network in the HANDOVER COMMAND message.

Before completion of the 4 access bursts on the DCCH, additional access bursts may also be sent on the SACCH.

In those cells that support extended TA values if TA value in new cell is greater than 63 and the HANDOVER COMMAND message indicates that the transmission of four HANDOVER ACCESS messages is optional the MS shall not transmit these four messages. MS shall not send additional bursts on the SACCH.

It then activates the channels in sending and receiving mode and connects the channels if need be.

If applicable, ciphering is immediately started . The access bursts are not ciphered.

3.4.4.2.2 Non synchronized cell case

After having switched to the assigned channels, the mobile station starts repeating the HANDOVER ACCESS message in successive layer 1 frames on the main DCCH and optionally on the SACCH. This message is sent in an access burst. Its content is reduced to the handover reference information element. The mobile station starts timer T3124 at the start point of the timeslot in which the HANDOVER ACCESS message is sent the first time on the main DCCH.

The mobile station then activates the channels in receiving mode and connects the channels if need be (only for reception).

If applicable, deciphering is then immediately started . The access bursts are not ciphered.

When the network has the RF characteristics that are necessary, it sends in unacknowledged mode a PHYSICAL INFORMATION message to the mobile station on the main DCCH. If applicable, ciphering and deciphering is immediately started (i.e., before even the reception of a correct access burst), and the message is sent enciphered.

The PHYSICAL INFORMATION message contains various physical layer related information, allowing a proper transmission by the mobile station.

When sending the PHYSICAL INFORMATION message, the network starts timer T3105. If this timer times out before the reception of a correctly decoded layer 2 frame in format A or B (see 3GPP TS 04.06), or a correctly decoded TCH frame from the mobile station, the network repeats the PHYSICAL INFORMATION message and restarts timer T3105. The maximum number of repetitions is Ny1.

The correct decoding of a frame means that the decoding algorithm and the error detection tests, if any, indicate no error.

When the mobile station receives a PHYSICAL INFORMATION message, it stops timer T3124, stops sending access bursts, activates the physical channels in sending and receiving mode and connects the channels if need be. If the allocated channel is an SDCCH (+ SACCH), performance of the mobile station must enable the mobile station to accept a correct PHYSICAL INFORMATION message sent by the network in any block while T3124 is running.

3.4.4.2.3 Pseudo-synchronized cell case

The details of the use of this procedure are described in 3GPP TS 05.10. The mobile station computes the timing advance to be used with the new cell from the real time difference value given in the HANDOVER COMMAND message. If the mobile station knows that the timing advance with the new cell is not out of range , i.e. smaller or equal to the maximum timing advance that can be coded as specified in 3GPP TS 04.04, or if the new cell accepts an out of range timing advance as indicated in the HANDOVER COMMAND message, the mobile station switches to the new channel and proceeds as follows.

After having switched to the assigned channels, the mobile station sends in four successive slots on the main DCCH a HANDOVER ACCESS message. This message is sent in random mode and thus does not follow the basic format. Its content is reduced to the handover reference information element. The transmission of these four messages is optional if so indicated by the network in the HANDOVER COMMAND message.

Before completion of the 4 access bursts on the DCCH, additional access bursts may also be sent on the SACCH.

In those cells that support extended TA values if TA value in new cell is greater than 63 and the HANDOVER COMMAND message indicates that the transmission of four HANDOVER ACCESS messages is optional the MS shall not transmit these four messages. The MS shall not send additional bursts on the SACCH.

The mobile station then activates the channels in sending and receiving mode and connects the channels if need be. The mobile station may activate the channels in receiving mode and connect the channels while sending access bursts.

If applicable, ciphering is then immediately started. The access bursts are not ciphered.

3.4.4.2.4 Pre-synchronized cell case

The details of the use of this procedure are described in 3GPP TS 05.10. The mobile station switches to the new channel and proceeds as follows.

After having switched to the assigned channels, the mobile station sends in four successive slots on the main DCCH a HANDOVER ACCESS message. This message is sent in an access burst and thus does not follow the basic format. Its content is reduced to the handover reference information element. The transmission of these four messages is optional if so indicated by the network in the HANDOVER COMMAND message.

Before completion of the 4 access bursts on the DCCH, additional access bursts may also be sent on the SACCH.

In those cells that support extended TA values if TA value in new cell is greater than 63 and the HANDOVER COMMAND message indicates that the transmission of four HANDOVER ACCESS messages is optional the MS shall not transmit these four messages. MS shall not send additional bursts on the SACCH.

The mobile station then activates the channel in sending and receiving mode and connects the channels if need be. The timing advance value to be used with the new cell is:

– either the value contained in the HANDOVER COMMAND message if the timing advance information element is present;

– or the default value for pre-synchronized handover as defined in 3GPP TS 05.10, if the timing advance information element is not included in the HANDOVER COMMAND message. The MS may activate the channels in receiving mode and connect the channels while sending access bursts.

If applicable, ciphering is immediately started. The access bursts are not ciphered.

3.4.4.3 Handover completion

After lower layer connections are successfully established, the mobile station returns a HANDOVER COMPLETE message, specifying cause "normal event", to the network on the main DCCH.

The sending of this message on the mobile station side and its receipt on the network side allow the resumption of the transmission of signalling layer messages other than those for RR management.

When receiving the HANDOVER COMPLETE message, the network stops timer T3103 and releases the old channels.

If requested to do so in the HANDOVER COMMAND message, the mobile station includes the observed time difference it has measured when performing the handover, corrected by half the timing advance, in the HANDOVER COMPLETE message (detailed specifications are given in 3GPP TS 05.10).

If the new cell supports DTM and the mobile station was in DTM in the old cell or the network does not have enough information about the RR mode in the old cell, the network sends the DTM INFORMATION message on the main DCCH after the HANDOVER COMPLETE message has been received.

3.4.4.4 Abnormal cases

In the case of a synchronous or pseudo-synchronous handover, if the mobile station knows that the timing advance with the new cell is out of range, i.e. is bigger than the maximum timing advance that can be coded as specified in 3GPP TS 04.04, and if the new cell does not accept out of range timing advance as indicated in the HANDOVER COMMAND message, the mobile station sends a HANDOVER FAILURE message, cause "handover impossible, timing advance out of range", on the main signalling link and does not attempt that handover.

If the HANDOVER COMMAND message instructs the mobile station to use a Channel Description or Mode that it does not support, or if the Channel Mode to use is not defined for all channel sets, then the MS shall return a HANDOVER FAILURE message with cause "channel mode unacceptable", and the MS shall remain on the current channel(s) and uses the old Channel Description or Mode(s).

If the mobile station receives a HANDOVER COMMAND message containing an inconsistent MultiRateConfiguration IE, then the mobile station shall return a HANDOVER FAILURE message with cause "channel mode unacceptable", and the mobile station shall remain on the current channel(s) and uses the old Channel Description or Mode(s).

The MultiRate Configuration IE shall be considered as inconsistent by the MS if:

– the active set does not include any codec mode or the active set includes more than four codec modes; or

– one or more codec modes of the active codec set are not supported by the assigned channel; or

– the threshold and hysteresis values are not set according to requirements given in 3GPP TS 05.09.

If the HANDOVER COMMAND message instructs the mobile station to use a frequency that it is not capable of, then the mobile station shall return a HANDOVER FAILURE message with cause "frequency not implemented", and the mobile station shall remain on the current channel(s).

If the mobile station receives a HANDOVER COMMAND message with a Frequency List IE or Frequency Short List IE indicating frequencies that are not all in one band, then the mobile station shall stay on the current channel(s) and send a HANDOVER FAILURE message with cause "frequency not implemented". If the mobile station receives a HANDOVER COMMAND message with a Mobile Allocation IE indexing frequencies that are not all in one band, then the mobile station shall stay on the current channel(s) and send a HANDOVER FAILURE message with cause "frequency not implemented".

NOTE: A HANDOVER COMMAND message sent to a multi band mobile station shall not be considered invalid because it indicates target channel frequencies that are all in a different frequency band to that of the ARFCN in the Cell Description IE.

On the mobile station side, if timer T3124 times out (only in the non- synchronized case) or if a lower layer failure happens on the new channel before the HANDOVER COMPLETE message has been sent, the mobile station deactivates the new channels, reactivates the old channels, reconnects the TCHs if any and triggers the establishment of the main signalling link. It then sends a HANDOVER FAILURE message on the main signalling link and resumes normal operation as if no handover attempt had occurred. The operational parameters (e.g. ciphering mode) when returning on the old channel are those applied before the HANDOVER COMMAND message was received.

When the HANDOVER FAILURE message has been received, the network releases the new channels if they were dedicated channels and stops timers T3105 and stops T3103 in the non-synchronized case. If the new channels were VGCS channels, they shall be maintained.

If a lower layer failure happens while attempting to connect back to the old channels, the standard rules are applied (see sub-clause 3.4.13.2 for dedicated mode and sub-clause 3.4.13.5 for group transmit mode).

On the network side, if timer T3103 elapses before either the HANDOVER COMPLETE message is received on the new channels, or a HANDOVER FAILURE message is received on the old channels, or the mobile station has re-established the call, the old channels are released if they were dedicated channels and all contexts related to the connections with that mobile station are cleared. If the old channel was a VGCS channel, it shall be maintained and the uplink shall be set free.

On the network side, if neither a correctly layer 2 frame in format A or B nor a correctly TCH frame have been received from the mobile station on the new channel, the newly allocated channels are released if they were dedicated channels. If the new channels were VGCS channels, they shall be maintained and the uplink shall be set free.

On the network side, lower layer failures occurring on the old channels after the sending of the HANDOVER COMMAND message are ignored. Lower layer failures occurring after the receipt of the SABM frame on the new main signalling link are treated following a general scheme (see sub-clause 3.4.13.2 for dedicated mode and sub-clause 3.4.13.5 for group transmit mode).

3.4.4a Handover to UTRAN procedure

Only valid for a UTRAN capable MS. In dedicated mode or dual transfer mode, a change to UTRAN channel(s) can be requested by the network RR sublayer. This change is performed through the handover to UTRAN procedure.

NOTE: The decision to do a handover to UTRAN and the choice of the new cell is out of the scope of the present document.

The handover to UTRAN procedure includes:

– The suspension of normal operation except for RR management (layer 3).

– The disconnection of the main signalling link, and of the other links via local end release (layer 2), and the disconnection of the TCH(s) if any.

– The disconnection and the deactivation of previously assigned channels and their release (layer 1).

– The abortion of the packet resources (see 3GPP TS 04.60), if in class A mode of operation.

– The establishment of UTRAN channel(s), see 3GPP TS 25.331.

The handover to UTRAN procedure is always initiated by the network.

3.4.4a.1 Handover to UTRAN initiation

The network initiates the handover to UTRAN procedure by sending an INTER SYSTEM TO UTRAN HANDOVER COMMAND message to the mobile station on the main DCCH. It then starts timer T3121.

If the INTER SYSTEM TO UTRAN HANDOVER COMMAND refers to a not known cell (see 3GPP TS 25.133 and 3GPP TS 25.123), this shall not be considered as an error.

When sending this message on the network side, and when receiving it on the mobile station side, all transmission of signalling layer messages except for those RR messages needed for this procedure and for abnormal cases, is suspended until resuming is indicated. These RR messages can be deduced from sub-clause 3.4.3 and 8.5.1 "Radio Resource management".

Upon receipt of the INTER SYSTEM TO UTRAN HANDOVER COMMAND message, the mobile station initiates, as described in sub-clause 3.1.4, the release of link layer connections and disconnects the physical channels (including the packet resources, if in class A mode of operation). Switching to the assigned cell(s) and physical channel establishment is described in 3GPP TS 25.331.

3.4.4a.2 Handover to UTRAN completion

NOTE: After lower layer connections are successfully established, the mobile station returns a Handover to UTRAN Complete message on UTRAN channels(s), see 3GPP TS 25.331.

When receiving the Handover to UTRAN Complete message (3GPP TS 25.331), the network stops timer T3121 and releases the old channels.

3.4.4a.3 Abnormal cases

If the INTER SYSTEM TO UTRAN HANDOVER COMMAND message instructs the mobile station to use a frequency that it is not capable of, then the mobile station shall stay on the current channel(s) and return a HANDOVER FAILURE message with cause "frequency not implemented".

If the INTER SYSTEM TO UTRAN HANDOVER COMMAND message instructs the mobile station to use a UTRAN predefined configuration that the mobile station has not read or instructs to use a default configuration not implemented by the mobile station, then the mobile station shall stay on the current channel(s) and return a HANDOVER FAILURE message with cause "UTRAN configuration unknown". If connection is not possible on the UTRAN channel(s) (see 3GPP TS 25.331), the MS reactivates the old channel(s) and reconnects TCHs and triggers the establishment of the main signalling link. It then sends a HANDOVER FAILURE message on the main signalling link and resumes normal operation.

When sending a HANDOVER FAILURE message in response to an INTERSYSTEM TO UTRAN HANDOVER COMMAND, the mobile station shall erase all the UTRAN predefined configurations.

When the HANDOVER FAILURE message has been received, the network releases the UTRAN channel(s) if they were dedicated channels and stops timer T3121.

If a lower layer failure happens while attempting to connect back to the old channels, the standard rules are applied (see sub-clause 3.4.13.2 for dedicated mode).

On the network side, if timer T3121 elapses before either the Handover to UTRAN Complete (3GPP TS 25.331) message is received on the UTRAN channel(s), or a HANDOVER FAILURE message is received on the old channels, or the mobile station has re-established the call, the old channels are released if they were dedicated channels and all contexts related to the connections with that mobile station are cleared.

On the network side, lower layer failures occurring on the old channels after the sending of the INTER SYSTEM TO UTRAN HANDOVER COMMAND message are ignored.

3.4.4b Handover to CDMA2000 procedure

Only valid for a CDMA2000 capable MS. In dedicated mode or dual transfer mode, a change to CDMA2000 channel(s) can be requested by the network RR sublayer. This change is performed through the handover to CDMA2000 procedure.

NOTE: The decision to do a handover to CDMA2000 and the choice of the new cell is out of the scope of the present document.

The handover to CDMA2000 procedure includes:

– The suspension of normal operation except for RR management (layer 3).

– The disconnection of the main signalling link, and of the other links via local end release (layer 2), and the disconnection of the TCH(s) if any.

– The disconnection and the deactivation of previously assigned channels and their release (layer 1).

– The abortion of the packet resources (see 3GPP TS 04.60), if in class A mode of operation.

– The establishment of CDMA2000 channel(s), see TIA/EIA/IS-833 and TIA/EIA/IS-2000.5-A.

The handover to CDMA2000 procedure is always initiated by the network.

3.4.4b.1 Handover to CDMA2000 initiation

The network initiates the handover to CDMA2000 procedure by sending an INTER SYSTEM TO CDMA2000 HANDOVER COMMAND message to the mobile station on the main DCCH. It then starts timer T3123.

If the INTER SYSTEM TO CDMA2000 HANDOVER COMMAND refers to a not known base station (see TIA/EIA-98), this shall not be considered as an error.

When sending this message on the network side, and when receiving it on the mobile station side, all transmission of signalling layer messages except for those RR messages needed for this procedure and for abnormal cases, is suspended until resuming is indicated. These RR messages can be deduced from sub-clause 3.4.3 and sub-clause 8.5.1.

Upon receipt of the INTER SYSTEM TO CDMA2000 HANDOVER COMMAND message, the mobile station initiates, as described in sub-clause 3.1.4, the release of link layer connections and disconnects the physical channels (including the packet resources, if in class A mode of operation). Switching to the assigned base stations and physical channel establishment is described in TIA/EIA/IS-2000.5-A.

3.4.4b.2 Handover to CDMA2000 completion

NOTE: After lower layer connections are successfully established, the mobile station returns a Handoff Completion Message on CDMA2000 channels(s), see TIA/EIA/IS-833.

When receiving the Handoff Completion Message (TIA/EIA/IS-833), the network stops timer T3123 and releases the old channels.

3.4.4b.3 Abnormal cases

If the INTER SYSTEM TO CDMA2000 HANDOVER COMMAND message instructs the mobile station to use a frequency that it is not capable of, then the mobile station shall return a HANDOVER FAILURE message with cause "frequency not implemented", and the mobile station shall remain on the current channel(s).

If connection is not possible on the CDMA2000 channel(s) (see TIA/EIA/IS-2000.5-A), the MS reactivates the old channels, reconnects TCHs and triggers the establishment of the main signalling link. It then sends a HANDOVER FAILURE message on the main signalling link and resumes normal operation.

When the HANDOVER FAILURE message has been received, the network releases the CDMA2000 channel(s) if they were dedicated channels and stops timer T3123.

If a lower layer failure happens while attempting to connect back to the old channels, the standard rules are applied (see sub-clause 3.4.13.2 for dedicated mode).

On the network side, if timer T3123 elapses before either the Handoff Completion Message (TIA/EIA/IS-833) is received on the CDMA2000 channel(s), or a HANDOVER FAILURE message is received on the old channels, or the mobile station has re-established the call, the old channels are released if they were dedicated channels and all contexts related to the connections with that mobile station are cleared.

On the network side, lower layer failures occurring on the old channels after the sending of the INTER SYSTEM TO CDMA2000 HANDOVER COMMAND message are ignored.

3.4.5 Frequency redefinition procedure

In dedicated mode, dual transfer mode and group transmit mode, this procedure is used by the network to change the frequencies and hopping sequences of the allocated channels. This is meaningful only in the case of frequency hopping.

The network sends to the mobile station a FREQUENCY REDEFINITION message containing the new parameters together with a starting time indication.

NOTE: The network should take into account limitations of certain mobile stations to understand formats used in the Cell Channel Description IE used in the FREQUENCY REDEFINITION message, see sub-clause 10.5.2.13.

When receiving such a message, the mobile station modifies the frequencies/hopping sequences it uses at the exact indicated time slot, i.e. the indicated time slot is the first with new parameters. All other functions are not disturbed by this change. New parameters can be the cell channel description, the mobile allocation and the MAIO. In case of multislot configuration, the Channel Description IE shall describe the channel carrying the main signalling link, the new parameters however, shall be used for all assigned timeslots. Other parameters describing the allocated channels must be identical to the current parameters.

3.4.5.1 Abnormal cases

If the mobile station receives a FREQUENCY REDEFINITION message with a Mobile Allocation IE indexing frequencies that are not all in one band and a Starting Time IE indicating a time that has not elapsed, then the mobile station shall stay on the current channel(s) and send a RR STATUS message with cause "frequency not implemented".

If the mobile station receives a FREQUENCY REDEFINITION message with a Mobile Allocation IE indexing frequencies that are not all in one band and a Starting Time IE indicating a time that has elapsed, then the mobile station shall locally abort the radio connection and, if permitted, attempt Call Re-establishment.

If the mobile station receives a FREQUENCY REDEFENITION message on a channel for which it has a pending redefinition (defined by the immediate assignment, assignment or handover procedure or a previous frequency redefinition procedure) the frequencies, hopping and starting time parameters defined by the new frequency redefinition procedure supersedes those of the pending one.

NOTE: A FREQUENCY REDEFINITION message sent to a multi band mobile station shall not be considered invalid because it indicates new frequencies that are all in a different frequency band to that of the ARFCN of the serving cell.

3.4.6 Channel mode modify procedure

In dedicated mode, dual transfer mode or group transmit mode, higher layers can request the setting of the channel mode.

The channel mode modify procedure allows the network to request the mobile station to set the channel mode for one channel or one channel set. The procedure shall not be used if the multislot configuration contains more than one channel set. The channel mode covers the coding, decoding and transcoding mode used on the indicated channel.

This message shall not be used to modify the mode of a non-multislot configured traffic channel when the MS has requested a multislot configuration, ie it cannot be used to modify the mode of a traffic channel when the channel was assigned during the immediate assignment procedure and the user has requested a multislot configuration.

This procedure is always initiated by the network.

NOTE: Direct transitions between full rate speech coder version 1 and full rate speech coder version 2 (and vice versa) may cause unpleasant audio bursts.

3.4.6.1 Normal channel mode modify procedure

3.4.6.1.1 Initiation of the channel mode modify procedure

The network initiates the procedure by sending a CHANNEL MODE MODIFY message to the mobile station. This message contains:

– a channel description of the channel(s) on which the mode in the CHANNEL MODE MODIFY message shall be applied; and

– the mode to be used on that channel, or on all the channels of a channel set in a multislot configuration;

– optionally, when the channel mode indicates that a multi-rate speech codec must be applied, the MultiRateconfiguration to be used. The MultiRateConfiguration IE defines the set of codec modes and related information to use after the mode modify procedure.

If the channel mode is changed from a non multi-rate speech codec to a multi-rate speech codec, the CHANNEL MODE MODIFY message shall contain the MultiRate Configuration IE, which defines the set of codec modes and related information to use as a new mode.

If the old channel mode and the new channel mode are both multi-rate speech codec, the MultiRate Configuration IE may not be present. If not present, the MS shall go on with the current multi-rate speech configuration.

3.4.6.1.2 Completion of channel mode modify procedure

When it has received the CHANNEL MODE MODIFY message, the mobile station sets the mode for the indicated channel, and if that is in a multislot configuration, the whole channel set and then replies by a CHANNEL MODE MODIFY ACKNOWLEDGE message indicating the ordered channel mode.

This applies whether the mode commanded by the CHANNEL MODE MODIFY is different from the one used by the mobile station or whether it is already in use.

3.4.6.1.3 Abnormal cases

If the new mode is multi-rate speech codec and if the MultiRate Configuration IE is inconsistent, the MS shall ignore the CHANNEL MODE MODIFY message and shall not send CHANNEL MODE MODIFY ACKNOWLEDGE message to the network.

No other specific action for a lower layer failure is specified in this sub-clause. If the mobile station does not support the indicated mode, it shall retain the old mode and return the associated channel mode information in the CHANNEL MODE MODIFY ACKNOWLEDGE message.

3.4.6.2 Channel mode modify procedure for a voice group call talker

3.4.6.2.1 Initiation of the channel mode modify procedure

The network initiates the procedure by sending a CHANNEL MODE MODIFY message to the mobile station. This message contains:

– a channel description of the channel on which the CHANNEL MODE MODIFY message is sent; and

– the new channel mode to be used on the channel; and

– optionally, the VGCS target mode information element defining which RR mode is to be used with the new channel mode (i.e. dedicated mode or group transmit mode). If this information element is not present, the RR mode shall be assumed to be the same as with the previous channel mode. The VGCS target mode information element shall also indicate the group cipher key number for the group cipher key to be used on the new channel or if the new channel is non ciphered. If the information element is not present, the ciphering mode and ciphering key shall be the same as with the previous channel mode. Mobile stations not supporting VGCS talking shall ignore the CHANNEL MODE MODIFY message if the VGCS target mode information element is included in the message and shall send an RR STATUS message to the network with cause #96.

The start of ciphering with a group cipher key with the new channel mode is only possible when the mode on the old channel was not ciphered.

If a VGCS target mode information element indicating a group cipher key number is included in the message and the previous mode is not non ciphered and the group cipher key number is different to the previous cipher key number, the mobile station shall behave as if it would not support the indicated channel mode.

3.4.6.2.2 Completion of mode change procedure

When it has received the CHANNEL MODE MODIFY message, the mobile station changes the mode for the indicated channel and then replies by a CHANNEL MODE MODIFY ACKNOWLEDGE message indicating the new channel mode.

3.4.6.2.3 Abnormal cases

No specific action for a lower layer failure is specified in this sub-clause. If the mobile station does not support the indicated mode, it shall retain the old mode and return the associated channel mode information in the CHANNEL MODE MODIFY ACKNOWLEDGE message.

3.4.7 Ciphering mode setting procedure

In dedicated mode, the ciphering mode setting procedure is used by the network to set the ciphering mode, i.e. whether or not the transmission is ciphered, and if so which algorithm to use. The procedure shall only be used to change from "not ciphered" mode to "ciphered" mode, or vice-versa, or to pass a CIPHERING MODE COMMAND message to the mobile station while remaining in the "not ciphered" mode. The ciphering mode setting procedure is always triggered by the network and it only applies to dedicated resources.

The cipher mode setting procedure shall not be applied in group transmit mode.

3.4.7.1 Ciphering mode setting initiation

The network initiates the ciphering mode setting procedure by sending a CIPHERING MODE COMMAND message to the mobile station on the main signalling link, indicating whether ciphering shall be used or not, and if yes which algorithm to use.

Additionally, the network may, by the use of the cipher response information element, request the mobile station to include its IMEISV in the CIPHERING MODE COMPLETE message.

The new mode is applied for reception on the network side after the message has been sent.

3.4.7.2 Ciphering mode setting completion

Whenever the mobile station receives a valid CIPHERING MODE COMMAND message, it shall, if a SIM is present and considered valid by the ME and the ciphering key sequence number stored on the SIM indicates that a ciphering key is available, load the ciphering key stored on the SIM into the ME. A valid CIPHERING MODE COMMAND message is defined to be one of the following:

– one that indicates "start ciphering" and is received by the mobile station in the "not ciphered" mode;

– one that indicates "no ciphering" and is received by the MS in the "not ciphered" mode; or

– one that indicates "no ciphering" and is received by the mobile station in the "ciphered" mode.

Other CIPHERING MODE COMMAND messages shall be regarded as erroneous, an RR STATUS message with cause "Protocol error unspecified" shall be returned, and no further action taken.

Upon receipt of the CIPHERING MODE COMMAND message indicating ciphering, the mobile station shall start transmission and reception in the indicated mode.

When the appropriate action on the CIPHERING MODE COMMAND has been taken, the mobile station sends back a CIPHERING MODE COMPLETE message. If the "cipher response" field of the cipher response information element in the CIPHERING MODE COMMAND message specified "IMEI must be included" the mobile station shall include its IMEISV in the CIPHERING MODE COMPLETE message.

Upon receipt of the CIPHERING MODE COMPLETE message or any other correct layer 2 frame which was sent in the new mode, the network starts transmission in the new mode.

Figure 3.4.7.2.1: Ciphering mode setting sequence

3.4.8 Additional channel assignment procedure

NOTE: In the present state of 3GPP TS 04.03, this procedure is only possible for the TCH/H + ACCHs to TCH/H + TCH/H + ACCHs transition. As a consequence it is not needed for simple mobile stations. The description of the procedure is in general terms to cope with possible evolution.

In dedicated mode, a change of channel configuration to include an additional channel can be requested by upper layers.

The additional channel assignment procedure shall not be applied in group transmit mode.

The purpose of the additional assignment procedure is to allocate an additional dedicated channel to a mobile station while keeping the previously allocated channels. In particular the main DCCH and the SACCH are not modified, and signalling exchanges are not interrupted.

The additional assignment procedure may happen only in dedicated mode. It is used for instance for the transition from the TCH/H + ACCHs configuration to the TCH/H + TCH/H + ACCHs configuration.

The additional assignment procedure is always initiated by the network.

3.4.8.1 Additional assignment procedure initiation

The network initiates the procedure by sending an ADDITIONAL ASSIGNMENT message to the mobile station on the main DCCH. The ADDITIONAL ASSIGNMENT message contains the description of the newly assigned channel.

On receipt of the message, the mobile station activates the new channel.

3.4.8.2 Additional assignment procedure completion

The mobile station sends an ASSIGNMENT COMPLETE message to the network on the channel, on which it receives the ADDITIONAL ASSIGNMENT message.

3.4.8.3 Abnormal cases

A lower layer failure occurring during the procedure is treated according to the general case (see sub-clause 3.4.13.2).

The network considers the channel as allocated from the sending of the ADDITIONAL ASSIGNMENT message. As a consequence, if a re-establishment occurs, the network will consider the context as if the mobile station has received the message, and the new configuration allocated after the re‑establishment may differ from the one the mobile station had before the re-establishment.

3.4.9 Partial channel release procedure

In dedicated mode, a change of channel configuration to release one channel can be requested by upper layers.

The partial channel release procedure shall not be applied in group transmit mode.

The purpose of this procedure is to deactivate part of the dedicated channels in use. The channel configuration remains dedicated.

NOTE: In the present state of 3GPP TS 04.03, this procedure is only possible for the TCH/H + TCH/H + ACCHs to TCH/H + ACCHs transition. As a consequence it is not needed for simple mobile stations.

The partial release procedure is always initiated by the network.

3.4.9.1 Partial release procedure initiation

The network initiates the partial release by sending a PARTIAL RELEASE message to the mobile station on the main DCCH.

On receipt of the PARTIAL RELEASE message the mobile station:

– Initiates the disconnection of all the link layer connections carried by the channel to be released.

– Simultaneously initiates the connection on remaining channels of the data link layer connections that have been released.

– Deactivates the physical channels to be released.

– Sends a PARTIAL RELEASE COMPLETE to the network on the (possibly new) main signalling link.

3.4.9.2 Abnormal cases

A lower layer failure is treated following the general rules as specified in sub-clause 3.4.13.2.

Moreover, on the network side, the channel configuration nature is set from the sending of the PARTIAL RELEASE message onward. As a consequence, any new assignment after a re‑establishment may concern a different channel configuration nature from the one known by the mobile station before the re‑establishment.

3.4.10 Classmark change procedure

In dedicated mode or in group transmit mode, this procedure allows the mobile station to indicate to the network a change of characteristics reflected in the classmark (e.g. due to addition of power amplification). Furthermore, a mobile station which implements the "controlled early classmark sending" option may also send a CLASSMARK CHANGE message and/or a UTRAN CLASSMARK CHANGE message and/or a CDMA2000 CLASSMARK CHANGE message as described in sub-clause 3.3.1.1.4.1, even if no change of characteristics has occurred.

The mobile station sends a CLASSMARK CHANGE message to the network. This message contains the new mobile station classmark 2 information element. It may also contain a Classmark 3 Information Element. There is no acknowledgement from the network at layer 3.

A UTRAN capable MS, indepently of sending a CLASSMARK CHANGE message, sends a UTRAN CLASSMARK CHANGE message to the network. This message contains the INTER RAT HANDOVER INFO defined in 3GPP TS 25.331 There is no acknowledgement from the network at layer 3.

NOTE: For the network, UTRAN predefined configuration status information may be invalid if the PLMN where predefined configurations were read and the PLMN of the connected cell do not use common predefined configurations.

If the CLASSMARK CHANGE and one or more of these additional messages are to be sent by the MS, the CLASSMARK CHANGE message shall be sent first.

3.4.11 Classmark interrogation procedure

This procedure allows the network to request additional classmark information from the mobile station (e.g. if the information initially sent by the mobile station is not sufficient for network decisions). For a multi-RAT MS this procedure allows in addition the network to request INTER RAT HANDOVER INFO or CDMA2000 MS Capability information..

3.4.11.1 Classmark interrogation initiation

The network initiates the classmark interrogation procedure by sending a CLASSMARK ENQUIRY message to the mobile station on the main DCCH.

3.4.11.2 Classmark interrogation completion

On receipt of the CLASSMARK ENQUIRY message the mobile station sends a CLASSMARK CHANGE and/or a UTRAN CLASSMARK CHANGE and/or a CDMA2000 CLASSMARK CHANGE message to the network on the main DCCH. The Classmark Enquiry Mask information element in the CLASSMARK ENQUIRY message indicates the type of request. If the Classmark Enquiry Mask information element is not included in the CLASSMARK ENQUIRY message, this indicates a request for CLASSMARK CHANGE message.

The CLASSMARK CHANGE message contains the mobile station classmark 2 information element. It may also contain a Classmark 3 Information Element.

The UTRAN CLASSMARK CHANGE message contains the INTER RAT HANDOVER INFO (UTRAN specific information).

The CDMA2000 CLASSMARK CHANGE message contains CDMA2000 UE capability information.

If the CLASSMARK CHANGE and one or more of these additional messages are to be sent by the MS, the CLASSMARK CHANGE message shall be sent first.

3.4.12 Indication of notifications and paging information

Only applicable for mobile stations supporting VGCS or VBS:

– In dedicated mode or in group transmit mode, the RR entity shall provide indications to the upper layer on all received notifications for voice group calls or voice broadcast calls according to the VGCS or VBS subscription data stored in the mobile station. The indication shall include the notified group or broadcast call reference and possibly the related priority, if provided.

– In group transmit mode, if the mobile station has decoded a paging message with the own mobile station identity on the PCH or on the voice group call channel downlink, the RR entity shall provide an indication to the upper layers, together with the related priority, if applicable.

– In group transmit mode, if the RR entity receives information on the voice group call channel of the existence of a paging message in its paging subgroup of the PCH, the RR entity shall pass this information to the upper layers together with the related priority if provided (see also sub-clause 3.3.2 and sub-clause 3.3.3).

3.4.13 RR connection release procedure

3.4.13.1 Normal release procedure

The release of the RR connection can be requested by upper layers.

The purpose of this procedure is to deactivate all the dedicated channels in use. When the channels are released and the mobile station is not IMSI attached for GPRS services (clause 4), the mobile station returns to the CCCH configuration, idle mode.

If the mobile station is IMSI attached for GPRS services the following three cases apply:

– If the mobile station has no radio resources (i.e., no temporary block flow) allocated on a PDCH, the mobile station returns to the PCCCH or CCCH configuration, packet idle mode.

– If the mobile station is operating in dual transfer mode when the RR connection is released, the radio resources allocated on a PDCH are released, the mobile station returns to the PCCCH or CCCH configuration, packet idle mode.

– Otherwise, if the mobile station has radio resources allocated on a PDCH, the mobile station enters packet transfer mode.

The channel release procedure can be used in a variety of cases, including TCH release after a call release, and DCCH release when a dedicated channel allocated for signalling is released.

In dedicated mode and group transmit mode, the channel release procedure is always initiated by the network.

3.4.13.1.1 Channel release procedure initiation in dedicated mode and in group transmit mode

The network initiates the channel release by sending a CHANNEL RELEASE message to the mobile station on the main DCCH, starts timer T3109 and deactivates the SACCH.

On receipt of a CHANNEL RELEASE message the mobile station starts timer T3110 and disconnects the main signalling link. When T3110 times out, or when the disconnection is confirmed, the mobile station deactivates all channels, considers the RR connection as released, and returns to CCCH idle mode, returns to PCCCH or CCCH packet idle mode or enters packet transfer mode.

NOTE 1: Data Links other than the main signalling link are disconnected by local end link release.

If case of dedicated mode, on the network side, when the main signalling link is disconnected, the network stops timer T3109 and starts timer T3111. When timer T3111 times out, the network deactivates the channels, they are then free to be allocated to another connection.

NOTE 2: The sole purpose of timer T3111 is to let some time to acknowledge the disconnection and to protect the channel in case of loss of the acknowledge frame.

If timer T3109 times out, the network deactivates the channels; they are then free to be allocated to another connection.

The CHANNEL RELEASE message will include an RR cause indication as follows:

#0: if it is a normal release, e.g. at the end of a call or at normal release of a DCCH.

#1: to indicate an unspecified abnormal release.

#2, #3 or #4: to indicate a specific release event.

#5: if the channel is to be assigned for servicing a higher priority call (e.g. an emergency call).

#65: if e.g. a handover procedure is stopped because the call has been cleared.

The CHANNEL RELEASE message may include the information element BA Range which may be used by a mobile station in its selection algorithm (see 3GPP TS 05.08 and 3GPP TS 03.22).

Mobile stations not supporting VGCS or VBS listening shall ignore Group Channel Description, Group Cipher Key Number and Cell Channel Description information elements if present in the message and perform the channel release procedure as normal.

For mobile stations supporting VGCS listening, the following procedures apply.

The CHANNEL RELEASE message may include the Group Channel Description, and possibly the Cell Channel Description information element(s). In this case, the mobile station shall release the layer 2 link, enter the group receive mode and give an indication to the upper layer. If a CHANNEL RELEASE message with neither Group Channel Description nor Cell Channel Description is received, or if those information elements do not properly specify a group channel, the normal behaviour applies.

If ciphering is applied on the VGCS or VBS channel, the network shall provide in the CHANNEL RELEASE message with the Group Cipher Key Number information element for the group cipher key to be used by the mobile station for reception of the VGCS or VBS channel. If this information element is not included, no ciphering is applied on the VGCS or VBS channel.

A mobile station not supporting the "GPRS" option shall consider the GPRS Resumption information element as an information element unknown in the CHANNEL RELEASE message and perform the RR connection release procedure as normal.

For a mobile station supporting the "GPRS" option, the following additional procedures also apply:

– The CHANNEL RELEASE message may include the information element GPRS Resumption. If the GPRS Resumption information element indicates that the network has resumed GPRS services, the RR sublayer of the mobile station shall indicate a RR GPRS resumption complete to the MM sublayer, see clause 4. If the GPRS Resumption information element indicates that the network has not successfully resumed GPRS services, the RR sublayer of the mobile station shall indicate a RR GPRS resumption failure to the MM sublayer, see clause 4.

– If the mobile station has performed the GPRS suspension procedure (sub-clause 3.3.1.1.4.2) and the GPRS Resumption information element is not included in the message, the RR sublayer of the mobile station shall indicate a RR GPRS resumption failure to the MM sublayer, see clause 4.

– If the mobile station has not performed the GPRS suspension procedure and the GPRS Resumption information element is not included in the message, the mobile station shall perform the RR connection release procedure as normal.

3.4.13.1.2 Abnormal cases

Abnormal cases are taken into account in the main part of the description of the procedure.

3.4.13.2 Radio link failure in dedicated mode or dual transfer mode

The main part of these procedures concerns the "normal" cases, i.e. those without any occurrence of loss of communication means. A separate paragraph at the end of the description of each procedure treats the cases of loss of communication, called a radio link failure. In dedicated mode, in most of the cases the reaction of the mobile station or the network is the same. Those reactions are described in this sub-clause to avoid repetitions.

A radio link failure can be detected by several ways:

1) By analysis of reception at layer 1, as specified in 3GPP TS 05.08 and sub-clause 3.4.1.1.

2) By a data link layer failure as specified in 3GPP TS 04.06, on the main signalling link. A data link failure on any other data link shall not be considered as a radio link failure.

3) When a lower layer failure happens while the mobile station attempts to connect back to the old channels in a channel assignment procedure, handover procedure, PDCH assignment procedure, RR-cell change order procedure or DTM assignment procedure with relocation of the RR connection.

4) In some cases where timers are started to detect the lack of answer from the other party, as described in clause 3.

The two first cases are known by the term "lower layer failure".

3.4.13.2.1 Mobile side

When a radio link failure is detected by the mobile station:

– the MS shall perform a local end release on all signalling links unless otherwise specified;

– the mobile station shall deactivate all dedicated channels;

– if the mobile station is in dual transfer mode, it shall abort the packet resources;

– the RR sublayer of the mobile station shall indicate an RR connection failure to the MM sublayer unless otherwise specified.

NOTE: Upper layers may decide on a re-establishment (see sub-clause 5.5.4).

When a mobile station which has performed the GPRS suspension procedure (sub-clause 3.3.1.1.4.2) detects a radio link failure, the RR sublayer of the mobile station shall indicate a RR GPRS resumption failure to the MM sublayer, see clause 4.

3.4.13.2.2 Network side

In dedicated mode, the reaction of the network to a lower layer failure depends on the context. Except when otherwise specified, it is to release the connection either with the channel release procedure as specified in sub-clause 3.5.1, or with the following procedure. The network starts timer T3109 and deactivates the SACCH (and hence to stop transmission on the SACCH). If the mobile station is in dual transfer mode, the network also aborts all the allocated packet resources.

When a radio link failure has been detected, an indication is passed to the upper Mobility Management sublayer on the network side.

When timer T3109 expires, the network can regard the channels as released and free for allocation.

This procedure relies on the fact that if a mobile station does not receive the SACCH for some time, it completely releases the channels (see 3GPP TS 05.08).

NOTE: The network should maintain for a while the transaction context in order to allow call re-establishment. The length of timer is for further study.

When a mobile station which has performed the GPRS suspension procedure (sub-clause 3.3.1.1.4.2) detects a radio link failure, the RR sublayer of the mobile station shall indicate a RR GPRS resumption failure to the MM sublayer, see clause 4.

3.4.13.3 RR connection abortion in dedicated mode or dual transfer mode

The mobile station aborts the RR connection by initiating a normal release of the main signalling link, performing local end releases on all other signalling links, disconnecting all traffic channels, if any, and aborting all the packet resources, if any.

When a mobile station which has performed the GPRS suspension procedure (sub-clause 3.3.1.1.4.2) aborts the RR connection, the RR sublayer of the mobile station shall indicate a RR GPRS resumption failure to the MM sublayer, see clause 4.

3.4.13.4 Uplink release procedure in group transmit mode

If the uplink release is requested by the upper layer the mobile station shall send an UPLINK RELEASE message on the voice group call channel uplink, perform a release of the main signalling link and go back to the group receive mode.

If the UPLINK RELEASE message is received from the network on the voice group call channel downlink, the MS shall perform a release of the main signalling link and go back to the group receive mode.

3.4.13.5 Radio link failure in group transmit mode

The main part of these procedures concerns the "normal" cases, i.e. those without any occurrence of loss of communication means. A separate paragraph at the end of the description of each procedure treats the cases of loss of communication, called a radio link failure. In group transmit mode, in most of the cases the reaction of the mobile station or the network is the same. Those reactions are described in this sub-clause to avoid repetitions.

A radio link failure can be detected by several ways:

1) By analysis of reception at layer 1, as specified in 3GPP TS 05.08 and sub-clause 3.4.1.1.

2) By a data link layer failure as specified in 3GPP TS 04.06, on the main signalling link. A data link failure on any other data link shall not be considered as a radio link failure.

3) When a lower layer failure happens while the mobile station attempts to connect back to the old channels in a channel assignment procedure or handover procedure.

4) In some cases where timers are started to detect the lack of answer from the other party, as described in clause 3.

The two first cases are known by the term "lower layer failure".

3.4.13.5.1 Mobile side

When a radio link failure is detected by the mobile station:

– the MS shall perform a local end release on all signalling links;

– the mobile station shall go back to idle mode and, when possible, to group receive mode;

– the RR sublayer of the mobile station shall indicate an RR connection failure to the MM sublayer unless otherwise specified.

3.4.13.5.2 Network side

When the uplink has been allocated and the network detects a lower layer failure, the network shall set the uplink free and provide an UPLINK FREE message on the main signalling channel, when appropriate.

When a radio link failure has been detected, an indication is passed to the upper Mobility Management sublayer on the network side.

3.4.13.6 RR connection abortion requested by upper layers

The purpose of this procedure is to abort the RR connection and bar the current cell. The procedure is requested by upper layers when they determine that the network has failed an authentication check (see 3GPP TS 24.008).

On request of the upper layers the MS shall locally abort the RR connection and behave as if a lower layer failure has occurred. The MS shall treat the current cell as barred (see 3GPP TS 03.22).

3.4.14 Receiving a RR STATUS message by a RR entity.

If the RR entity of the mobile station receives a RR STATUS message no transition and no specific action shall be taken as seen from the radio interface, i.e. local actions are possible.

The actions to be taken on receiving a RR STATUS message in the network are an implementation dependent option see also clause 8.

3.4.15 Group receive mode procedures

Only applicable for support of VGCS listening or VBS listening.

3.4.15.1 Mobile station side

3.4.15.1.1 Reception of the VGCS or VBS channel

In group receive mode, the mobile station receives the downlink of the voice broadcast channel or voice group call channel for which the channel description was provided within the notification message or in the related command message. The mobile station should also listen to the CCCH of the serving cell. Moreover, it measures the received levels on the serving cell and on the neighbour cells to assess the need for a cell reselection as specified in 3GPP TS 05.08. The general cell reselection procedure for the mobile station in group receive mode is described in 3GPP TS 03.22.

Information on neighbour cells used for cell reselection and reception of the VGCS or VBS channel in the neighbour cells may be provided on the downlink messages (see sub-clause 3.4.15.1.2). If no such information is provided or information is missing, the mobile station shall try to read this information on the BCCH and NCH of the neighbour cells.

3.4.15.1.2 Monitoring of downlink messages and related procedures

Mobile stations in group receive mode shall monitor messages related to the following procedures on the VGCS or VBS channel downlink and act appropriately in order to be able to keep receiving the VGCS or VBS channel downlink.

All messages for mobile stations in group receive mode shall be sent in UI format on the VGCS or VBS channel downlink. Mobile stations in group receive mode shall ignore all messages which are not sent in UI format or which are not related to the following mentioned procedures.

The mobile should also monitor messages on the PCH or NCH of the current cell.

3.4.15.1.2.1 (void)

3.4.15.1.2.2 (void)

3.4.15.1.2.3 Channel mode modify procedure

The mobile station shall receive CHANNEL MODE MODIFY messages. The mobile station shall use the new channel mode but shall not transmit any response to the network.

3.4.15.1.2.4 Notification and paging information

The mobile station shall monitor messages related to notification and paging procedures.

The RR entity shall provide indications on all received notifications for voice group calls or voice broadcast calls to the upper layer. The indication shall include the notified group or broadcast call reference and, if provided, and if the mobile station supports eMLPP the related priority.

On request by the upper layer to join another voice broadcast call or voice group call for which a corresponding notification has been received on the VGCS or VBS channel downlink, the RR entity shall read the corresponding notification on the NCH.

If the mobile station has received a paging message with its own mobile station identity on the PCH or on the voice broadcast channel or voice group call channel downlink, the RR entity shall provide an indication to the upper layers, together with the related priority, if applicable.

3.4.15.1.2.4.1 Use of Reduced NCH monitoring

This sub-clause applies to mobile stations which are in group receive mode or group transmit mode of dedicated mode and which in addition want to receive notification messages for other voice broadcast calls or voice group calls and which aim at reducing the reception load.

If the reduced NCH monitoring mechanism is used on the NCH as defined in sub-clause 3.3.3.3, when the MS in group receive mode or group transmit mode enters a cell, it should read the NCH until it has received at least two messages on the NCH indicating NLN, with the two last received NLN being identical. Then it should stop reading the NCH until it receives on the SACCH an NLN(SACCH) different from the last previously received NLN.

For this, a parameter is provided on the SACCH in the SYSTEM INFORMATION TYPE 6 message:

– NLN(SACCH): Notification List Number (received on the SACCH).

If a mobile station receives on the SACCH an NLN(SACCH) different from the last received NLN it may read the NCH until it has received at least two messages on the NCH indicating NLN with the two last received NLN being identical.

If a message in the SACCH is not received correctly the MS may read the NCH until it has received at least two messages on the NCH indicating NLN, with the two last received NLN being identical.

NOTE: If the NLN(SACCH) is not provided on the SACCH, the mobile station, depending on its particular implementation, may either read the NCH while being in group receive mode or group transmit mode or may not be able to receive notifications for other voice group calls or voice broadcast calls other than those notifications provided on the FACCH.

3.4.15.1.2.5 Uplink status messages

Mobile stations supporting VGCS talking shall monitor the VGCS uplink control related messages UPLINK FREE and UPLINK BUSY.

3.4.15.1.2.6 Channel release message

The mobile station shall receive CHANNEL RELEASE messages. On receipt of a CHANNEL RELEASE message, the RR entity shall go to idle mode and give an indication to the upper layer. (See also sub-clause 3.4.15.1.4.1, 4th paragraph.)

3.4.15.1.2.7 Information on paging channel restructuring

On receipt of a SYSTEM INFORMATION TYPE 6 message indicating that paging channel restructuring has taken place, if the mobile station wants to be able to read its paging subchannel while in group receive mode or group transmit mode, the mobile station should read the related messages on the BCCH to know the position of its paging group.

3.4.15.1.3 Uplink reply procedure

In Group Receive mode, on receipt of an UPLINK FREE message with an uplink access request indication from the network on the voice group call channel downlink, the mobile station shall send two UPLINK ACCESS messages on the voice group call channel with establishment cause "Reply on uplink access request" and then stop immediately transmitting on the uplink.

The first UPLINK ACCESS message shall be transmitted by the mobile station with a random delay between 0 ms and 20 ms. The second UPLINK ACCESS messages shall be repeated after a further period of 100 ms plus a random delay between 0 ms and 20 ms.

If an uplink identity code (UIC) of the current cell has been provided by the network in the UPLINK FREE message, the mobile station shall use this UIC for the coding of the UPLINK ACCESS messages. If no UIC is provided, the mobile station shall use the BSIC received of the serving cell, for instance as received from the initial synchronization.

3.4.15.1.4 Leaving the group receive mode

3.4.15.1.4.1 Returning to idle mode

If the mobile station enters a new cell in which:

– notifications for the current group or broadcast call are sent; but

– no VGCS or VBS channel description for the current group or broadcast call is provided;

the mobile station shall go to idle mode and give an indication to the upper (sub-)layers.

NOTE: Upper (sub-)layers then can request the establishment of an RR connection in order to be informed about the channel description by the network.

If the mobile station enters a cell in which notifications for the current group or broadcast call are not sent, the mobile station shall disconnect locally the TCH, go to idle mode and give an indication to the upper (sub-)layers.

On request by the upper layer in order to respond to a paging message the RR entity shall go to the idle mode in order to establish a dedicated RR connection.

On receipt of a CHANNEL RELEASE message in UI format from the network the RR entity shall go to idle mode and give an indication to the upper layer.

If the upper layer requests to abort the group receive mode, the mobile station shall go back to idle mode.

3.4.15.1.4.2 Going to group transmit mode

Only applicable for mobile stations supporting VGCS talking.

If the upper layer requests an uplink access, the mobile station shall perform the uplink investigation procedure as defined in sub-clause 3.3.1.2.1.1.

If the uplink investigation procedure is not successful, the mobile station shall give an indication to the upper layers and remain in group receive mode.

If the uplink investigation procedure is successful, the uplink access procedure is initiated as defined in sub-clause 3.3.1.2.1.2.

If the uplink access procedure is successful, the mobile station shall give an indication to the upper layers and enter the group transmit mode.

If the uplink access procedure is not successful, the mobile station shall give an indication to the upper layers and remain in group receive mode.

3.4.15.2 Network side

3.4.15.2.1 Provision of messages on the VGCS or VBS channel downlink

3.4.15.2.1.1 General

The network shall provide all messages directed to mobile stations in group receive mode (see sub-clause 3.4.15.1.2) in unacknowledged mode. Those messages which are also sent to the mobile station in group transmit mode in acknowledged mode have therefore to be repeated in addition as UI messages on the VGCS channel downlink if they shall also be received by mobile stations in group receive mode.

3.4.15.2.1.2 Provision of general information messages

In the case where the group call area exceeds one cell, the network should provide the SYSTEM INFORMATION TYPE 6 message on the SACCH related to the voice broadcast channel or voice group call channel.

In addition, if the group call area exceeds one cell, the network should provide SYSTEM INFORMATION TYPE 5 (possibly together with TYPE 5bis and 5ter) on the SACCH related to the voice broadcast channel or voice group call channel.

– The SYSTEM INFORMATION TYPE 5, TYPE 5bis and TYPE 5ter messages provide information on the BCCH frequency of the neighbour cells.

– The SYSTEM INFORMATION TYPE 6 message provides information on the location area of the current cell, possibly the status of the NCH, and an indication of whether paging channel restructuring has taken place.

– $(ASCI)$ Optional messages of the SYSTEM INFORMATION TYPE 10 message type provide information improving cell re-selection in group receive mode.

The network may also provide layer 3 messages for notification on the VGCS or VBS channel downlink FACCH.

3.4.15.2.1.3 Provision of messages related to the voice group call uplink channel

Only applicable for the support of VGCS talking.

The network shall provide UPLINK FREE messages on the main signalling link of all voice group call channels when the uplink is set free. The provision of UPLINK FREE messages shall be repeated as long as no uplink is granted to a mobile station.

The network shall provide an UPLINK BUSY message on the main signalling link of all voice group call when the uplink has been granted to a mobile station.

The network may send UPLINK FREE messages containing an uplink access request on the main signalling channel of the VGCS channels in order to obtain knowledge on whether any listening mobile is present in a cell or not. If there is no mobile station responding to the uplink access request, the network may decide to clear the VGCS channel in that cell.

3.4.15.2.2 Release of the VGCS or VBS Channels

If a release request for a voice group call is received from the upper layer, the network, after having released the RR connection with the mobile station in group transmit mode, shall stop the notification procedures for that voice group call and clear all related voice group call channels.

If a release request for a voice broadcast call is received from the upper layer, the network shall stop the notification procedures for that voice broadcast call and locally disconnect any channel related to the voice broadcast call.

3.4.15.3 Failure cases

If the mobile station looses the voice group call channel or voice broadcast channel, the mobile station shall search all possible channel positions on the current cell and the neighbour cells for which a channel description is known for that call.

3.4.16 Configuration change procedure

This is only applicable for multislot configuration. This message shall not be used to change a non-multislot configured channel to a multislot configured channel.

The configuration change procedure is used by the network to change the number of timeslots used in a multislot configuration. The procedure can also be used to change the channel mode of one or several channels and change their allocation. The main signalling link however, cannot be changed by the configuration change procedure. If a change of the main signalling link is needed, the assignment or handover procedures shall be used.

The network shall not initiate a new configuration change procedure before a response to the previous CONFIGURATION CHANGE COMMAND message has been received from the mobile station.

3.4.16.1 Configuration change initiation

The procedure starts when the network sends a CONFIGURATION CHANGE COMMAND to the mobile station on the main DCCH. The message indicates:

– which timeslots to use in uplink;

– which timeslots to use in downlink; and

– which channel set each timeslot belongs to.

The message may also contain definitions of the channel mode to be applied for one or several channel sets. If a previously undefined channel set is defined by the CONFIGURATION CHANGE COMMAND a definition of the channel mode for the new channel set shall be included in the message.

3.4.16.2 Configuration change completion

When the mobile station receives the CONFIGURATION CHANGE COMMAND it changes its configuration in accordance with the message contents and returns a CONFIGURATION CHANGE ACKNOWLEDGE on the same channel as the command message was received, confirming the new channel configuration. This applies irrespective of whether the new configuration is different from the one already in use by the mobile station or if it is the same.

3.4.16.3 Abnormal cases

If the CONFIGURATION CHANGE COMMAND message instructs the mobile station to use a Channel Configuration or Mode(s) that it does not support, or if the channel mode to use is not defined for all channel sets, the mobile station shall return a CONFIGURATION CHANGE REJECT message with cause ‘channel mode unacceptable’, and the mobile station shall remain on the current channel(s) and use the old Channel Configuration and Channel Mode(s).

3.4.17 Mapping of user data substreams onto timeslots in a multislot configuration

For multislot configurations the following rules for mapping of the user data substreams onto timeslots shall apply for each channel set:

– at initial assignment (using assignment procedure), the lowest numbered user data substream shall be mapped to the lowest numbered timeslot etc. in ascending order (the user data substreams are numbered 0 to (n-1), where n is the number of substreams).

– at channel changes using handover procedure or assignment procedure (where none of the timeslots are present in both the old and the new configuration), the lowest numbered user data substream shall be mapped to the lowest numbered timeslot etc. in ascending order (the user data substreams are numbered 0 to (n-1), where n is the number of substreams).

– at channel changes using assignment procedure (where at least one of the timeslots is the same in both the old and the new configuration) or configuration change procedure:

– user data substream(s) mapped to timeslot(s) that are present in both the old and the new configuration shall continue to be mapped to the same timeslot(s) as before the channel change; and

– possibly added timeslot(s) shall carry the lowest numbered available user data substream so that the lowest numbered data substream among the added is mapped to the lowest numbered added timeslot and so on in ascending order.

NOTE: The user data substream number is a number that need not be the same as the inband number used for transparent services. The user data substream number is only used as a point of reference to a specific user data substream.

3.4.18 Handling of classmark information at band change

The coding of some fields in the Mobile Station Classmark 1 and in the Mobile Station Classmark 2 information elements depends on the band in use as described in sub-clause 10.5.1.5 and sub-clause 10.5.1.6. When a command to change the frequency band (GSM 900, DCS 1800) has been received (by, e.g., an IMMEDIATE ASSIGNMENT message, an ASSIGNMENT COMMAND message, a HANDOVER COMMAND message or a FREQUENCY REDEFINITION message) the following applies:

– When an IMMEDIATE ASSIGNMENT message is received, "the band used" for the purpose of coding the classmark information in the service request message, see sub-clause 3.1.5, shall be understood as the band used for the CHANNEL REQUEST message or (one of) the band(s) indicated by the IMMEDIATE ASSIGNMENT message.

– For other cases "the band used" for the purpose of coding the classmark information shall be understood as one of the bands used or attempted to be used within the 2 seconds preceding the passing of the layer 3 message containing the classmark information to the layer 2 send queue as described in 3GPP TS 04.06.

NOTE: This definition means that when a band change is being done the network must take appropriate actions to handle possible ambiguities in the frequency band related information in the classmark.

3.4.19 Assignment to a Packet Data channel

This sub-clause is only applicable to mobile stations supporting the "GPRS" option.

When in dedicated mode or in group transmit mode, the network may wish to change the resources used by a mobile station that supports the "GPRS option". This change may be performed through the assignment to a Packet Data Channel procedure.

The purpose of the assignment to PDCH channel procedure is to completely modify the physical channel configuration of the mobile station without frequency redefinition or change in synchronization while staying in the same cell.

The assignment to PDCH procedure only commences in dedicated mode or in group transmit mode. This procedure cannot be used in the idle mode.

The assignment to PDCH procedure includes:

– the suspension of normal operation;

– the release of the main signalling link, and of the other data links as defined in sub-clause 3.1.4, and the disconnection of TCHs if any;

– the deactivation of previously assigned channels (layer 1);

– the triggering of the establishment of a Temporary Block Flow.

The assignment to PDCH procedure is always initiated by the network.

3.4.19.1 Assignment to PDCH initiation

The network initiates the assignment to PDCH procedure by sending a PDCH ASSIGNMENT COMMAND message to the mobile station on the main signalling link. It then starts timer T3117.

NOTE: The network should take into account limitations of certain mobile stations to understand formats used in the Frequency List IE and Cell Channel Description IE used in the PDCH ASSIGNMENT COMMAND message, see sub-clause 10.5.2.13 and sub-clause 10.5.2.1b.

When sending this message on the network side, and when receiving it on the mobile station side, all transmission of signalling layer messages except for those RR messages needed for this procedure and for abnormal cases is suspended until resumption is indicated. These RR messages can be deduced from sub-clause 3.4.3 and sub-clause 8.8 Radio Resource management.

Upon receipt of the PDCH ASSIGNMENT COMMAND message, the mobile station initiates a local end release of dedicated mode link layer connections, disconnects the physical channels, commands the switching to the identified channels and obeys the procedures relevant to the establishment of the Temporary Block Flow. The mobile station starts timer T3190.

The PDCH ASSIGNMENT COMMAND message contains the description of either the uplink TBF or the downlink TBF.

The information on the power to be used on the target TBF shall not affect the power used on the old channel(s).

A PDCH ASSIGNMENT COMMAND message may indicate a frequency change in progress, with a starting time and possibly alternative channel descriptions.

In the case of the reception of a PDCH ASSIGNMENT COMMAND message which contains only the description of a TBF to be used after the starting time, the mobile station shall wait up to the starting time before using the TBF. If the starting time has already elapsed, the mobile shall use the TBF as an immediate reaction to the reception of the message (see 3GPP TS 05.10 for the timing constraints).

If the message contains both the description of a TBF to be used after the indicated time and of a TBF to be used before, the mobile station uses the TBF as an immediate reaction to the reception of the message. If the moment the mobile station is ready to access is before the indicated time, the mobile station uses the TBF described for before the starting time. The mobile station then changes to the TBF described for after the starting time at the indicated time. New parameters can be frequency list, MAIO and HSN. Other parameters describing the allocated channels shall be identical to the parameters described for before the starting time. If the moment the mobile station is ready to access is after the starting time, the mobile station uses the TBF described for after the starting time.

If frequency hopping is applied, the cell allocation if present in the message is used to decode the mobile allocation. If the cell allocation is not included, the mobile station uses its current cell allocation, the current CA is the last CA received on the BCCH. Afterward, the current CA may be changed by some messages sent on the main signalling link containing a CA (the possible messages are: ASSIGNMENT COMMAND, HANDOVER COMMAND and FREQUENCY REDEFINITION). Note that there are cases in which the current CA is undefined, see sub-clause 3.4.3.3.

The PDCH ASSIGNMENT COMMAND does not contain a cipher mode setting IE. Any RR layer ciphering that may have been applied in dedicated mode shall not be applied to the target TBF.

3.4.19.2 Completion of the Assignment to PDCH procedure

The network regards the procedure as successfully completed when RLC/MAC blocks are received from the mobile station on the target TBF. The network then stops timer T3117.

The mobile station regards the procedure as successfully completed when RLC/MAC blocks with any TFI are received on the new PDCH.

3.4.19.3 Abnormal cases

If the mobile station has no current CA and if it needs a CA to analyse the PDCH ASSIGNMENT COMMAND message, it stays on the current channel(s) and sends an ASSIGNMENT FAILURE message with cause "no cell allocation available".

If the PDCH ASSIGNMENT COMMAND message instructs the mobile station to use a Coding Scheme that it does not support then the mobile station shall return an ASSIGNMENT FAILURE message with cause "channel mode unacceptable", and the mobile station shall remain on the current channel(s) and uses the old Channel Description or Channel Mode(s).

If the PDCH ASSIGNMENT COMMAND message instructs the mobile station to use a frequency that it is not capable of, then the mobile station shall return an ASSIGNMENT FAILURE message with cause "frequency not implemented", and the mobile station shall remain on the current channel(s).

If the mobile station receives a PDCH ASSIGNMENT COMMAND message with a Frequency List IE indicating frequencies that are not all in one band, then the mobile station shall stay on the current channel(s) and send an ASSIGNMENT FAILURE message with cause "frequency not implemented". If the mobile station receives a PDCH ASSIGNMENT COMMAND message with a Mobile Allocation IE indexing frequencies that are not all in one band, then the mobile station shall stay on the current channel(s) and send an ASSIGNMENT FAILURE message with cause "frequency not implemented".

NOTE: A PDCH ASSIGNMENT COMMAND message sent to a multi band mobile station shall not be considered invalid because it indicates frequencies that are all in a different frequency band to that of the current channel.

On the mobile station side, if RLC/MAC blocks are not successfully received within T3190 seconds, the mobile station reactivates the old channels, reconnects the TCHs if any and triggers the establishment of the main signalling link. It then sends an ASSIGNMENT FAILURE message, cause "protocol error unspecified" on the main DCCH and resumes the normal operation, as if no assignment attempt had occurred. The operational parameters (e.g. ciphering mode) when returning on the old channel are those applied before the procedure.

When receiving the ASSIGNMENT FAILURE message, the network stops T3117.

If a lower layer failure happens while attempting to connect back to the old channels, the radio link failure procedure is applied (see sub-clause 3.4.13.2).

On the network side, if timer T3117 elapses before either the network receives an RLC/MAC block from the mobile station on the new channel, or, an ASSIGNMENT FAILURE message is received on the old channels, then the old channels and the new resources are released, except that, if the old channel was a VGCS channel, the old channel shall be maintained and the uplink shall be set free.

On the network side, lower layer failure occurring on the old channels after the sending of the PDCH ASSIGNMENT COMMAND message are ignored.

3.4.20 RR-Network Controlled Cell Change Order

This sub-clause is only applicable to mobiles supporting the "GPRS" option.

In dedicated mode or in group transmit mode, intracell or intercell change of channel(s) can be requested by the network RR sublayer. This change may be performed through the RR-network controlled cell change order procedure.

The purpose of the RR-network controlled cell change order procedure is to permit the complete modification of the channels allocated to the mobile station e.g. when the cell is changed. This procedure only commences while in dedicated mode or in group transmit mode.

The RR-network controlled cell change order procedure includes:

– The suspension of normal operation except for RR management (layer 3).

– The disconnection of the main signalling link, and of the other links via local end release (layer 2), and the disconnection of the TCH(s) if any.

– The disconnection and the deactivation of previously assigned channels and their release (layer 1).

– The complete acquisition of BCCH or PBCCH messages of the target cell. For a UTRAN target cell, broadcast channel acquisitions are defined in 3GPP TS 25.331 instead.

– The triggering of the establishment of a Temporary Block Flow. For a UTRAN target cell, the behaviour following channel establishment is defined in 3GPP TS 25.331 instead.

The RR-network controlled cell change order procedure is always initiated by the network.

3.4.20.1 RR-network controlled cell change order initiation

The network initiates the RR-network controlled cell change order procedure by sending a RR-CELL CHANGE ORDER message to the mobile station on the main DCCH. The network then starts timer T3119.

When a handover has taken place during dedicated connection, the network shall send a RR-CELL CHANGE ORDER message to the mobile station in order to establish TBF. In this case the target cell is equal to the old cell.

When sending this message on the network side, and when receiving it on the mobile station side, all transmission of signalling layer messages except for those RR messages needed for this procedure and for abnormal cases, is suspended until resuming is indicated. These RR messages can be deduced from sub-clause 3.4.3 and sub-clause 8.5.1.

Upon receipt of the RR-CELL CHANGE ORDER message, the mobile station starts timer T3134, and initiates, as described in sub-clause 3.1.4, the release of link layer connections, disconnects the physical channels and commands the switching to the identified cell.

GERAN target cell: The mobile station then performs a complete acquisition of BCCH or PBCCH messages (see 3GPP TS 04.60), and obeys the procedures relevant to the establishment of the Temporary Block Flow. The mobile station shall obey the RR-CELL CHANGE ORDER message irrespective of whether or not the mobile station has any knowledge of the relative synchronisation of the target cell to the serving cell.

UTRAN target cell: Establishment of channel(s) is defined in 3GPP TS 25.331. A UTRAN capable mobile station shall obey the RR-CELL CHANGE ORDER message irrespective of whether the cell is know or not known (see 3GPP TS 25.133 and 3GPP TS 25.123).

The RR-CELL CHANGE ORDER message contains:

– The characteristics of the new cell that are necessary to identify it (i.e. BSIC + BCCH frequency). For a (3G) multi-RAT mobile station, the RR-CELL CHANGE ORDER message may contain information on a 3G target cell; in this case BSIC and BCCH frequency shall be ignored.

– The NC mode to be initially applied on the new cell.

The RR-CELL CHANGE ORDER does not contain a cipher mode setting IE. Any RR layer ciphering that may have been applied in dedicated mode shall not be applied to the target TBF or with the target cell.

3.4.20.2 Network controlled cell reselection completion

GSM target cell: The network regards the procedure as successfully completed when it knows that communication has been established with that mobile station via the new cell (e.g. the network has received a RLC/MAC Block containing the mobile station’s identity). The network then stops timer T3119.

The mobile station regards the procedure as successfully completed when it has received a response to a (PACKET) CHANNEL REQUEST message on the new cell which allocates it a resource on the new cell.

UTRAN target cell: The network regards the procedure as successfully completed when it knows that communication has been established with that mobile station via the new cell (see 3GPP TS 25.331). The network then stops timer T3119.

The mobile station regards the procedure as successfully completed when it has received a successful response to its RRC Connection Request message, see 3GPP TS 25.331.

3.4.20.3 Abnormal cases

If the RR-CELL CHANGE ORDER message instructs the mobile station to use a frequency that it is not capable of, then the mobile station shall return a HANDOVER FAILURE message with cause "frequency not implemented", and the mobile station shall remain on the current channel(s).

GSM target cell: On the mobile station side, if timer T3134 times out before a response to the (PACKET) CHANNEL REQUEST message has been received, or, if an IMMEDIATE ASSIGNMENT REJECT message or a PACKET ACCESS REJECT is received from the new cell, or, if the contention resolution procedure fails on the new cell then the mobile station shall reactivate the old channels, reconnect the TCHs if any and trigger the establishment of the main signalling link. It then sends a HANDOVER FAILURE message on the main signalling link and resumes normal operation as if no handover attempt had occurred. The operational parameters (e.g. ciphering mode) when returning on the old channel are those applied before the RR-CELL CHANGE ORDER message was received.

UTRAN target cell: On the mobile station side, if timer T3134 times out before a response to the RRC Connection Request message has been received on the new cell, or if a RRC Connection Reject message including Inter-RAT info set to ‘GSM’ is received from the new cell, then the mobile station shall reactivate the old channels, reconnect the TCHs if any and trigger the establishment of the main signalling link. It then sends a HANDOVER FAILURE message on the main signalling link and resumes normal operation as if no handover attempt had occurred. The operational parameters (e.g. ciphering mode) when returning on the old channel are those applied before the RR-CELL CHANGE ORDER message was received.

When the HANDOVER FAILURE message has been received, the network stops T3119.

If a lower layer failure happens while attempting to connect back to the old channels, the standard rules are applied (see sub-clause 3.4.13.2).

On the network side, if timer T3119 elapses before either the mobile station has been recognised on the new cell, or a HANDOVER FAILURE message is received on the old channels, then the old channels are released, except that, if the old channel was a VGCS channel, the old channel shall be maintained and the uplink shall be set free.

On the network side, lower layer failures occurring on the old channels after the sending of the RR-CELL CHANGE ORDER message are ignored.

3.4.21 Application Procedures

3.4.21.1 General

While in dedicated mode, the following applications associated with the Radio Resource management layer may be supported in the network and MS.

3.4.21.2 Location Services (LCS)

Common procedures are defined in the Radio Resource management layer to assist these applications.

3.4.21.3 Application Information Transfer

The Application Information Transfer procedure enables an Application on the network side and a peer application in the MS to exchange Application Protocol Data Units (APDUs).

3.4.21.3.1 Normal Procedure without Segmentation

The maximum size of an APPLICATION INFORMATION message is 251 octets as defined in 3GPP TS 04.06. Segmentation shall not be used when an APDU fits into a single APPLICATION INFORMATION message of maximum or smaller size.

Figure 3.4.21.3.4.1: Application Information Transfer without segmentation

Either the network or MS may send an APPLICATION INFORMATION message once the MS is in dedicated mode. The APDU Data in the APPLICATION INFORMATION message shall contain a complete APDU according to the protocol in use. The APDU ID IE identifies the protocol and associated application. The APDU Flags IE indicates "First or Only Segment", "Last or Only Segment" and conveys a C/R flag transparently between the communicating applications. The C/R Flag may be used to distinguish a command from other messages and a final response from a non-final response. The use of the C/R flag is defined with respect to each application. On receiving an APPLICATION INFORMATION message, the receiving layer 3 entity shall deliver the message contents to the identified local application.

3.4.21.3.2 Normal Procedure with Segmentation

Segmentation is applicable when an APDU is too large to fit into a single APPLICATION INFORMATION message. The procedure is applicable for either direction of transfer.

Figure 3.4.21.3.2.1: Application Information Transfer with segmentation

The sending layer 3 entity shall segment an APDU by dividing it into one or more segments exactly fitting into maximum sized APPLICATION INFORMATION messages plus a final segment fitting into an APPLICATION INFORMATION message of maximum size or smaller. Once segmented, the resulting APPLICATION INFORMATION messages shall be transferred in sequence to the data link layer for transmission, without being intersperced by other level 3 messages. The first APPLICATION INFORMATION message in the sequence shall indicate "First Segment" and "Not Last Segment". Subsequent APPLICATION INFORMATION messages except for the last shall indicate "Not First Segment" and "Not Last Segment". The last APPLICATION INFORMATION message shall indicate "Not First Segment" and "Last Segment" and shall include a C/R flag as provided by the sending application.

The receiving layer 3 entity shall reassemble any segmented APDU before transfer to the local application. The receiver may employ a timer to detect possible loss of APDU segments. If employed, the timer shall be started when the first APDU segment is received and cancelled after the last segment is received.

3.4.21.3.3 Abnormal Cases

APPLICATION INFORMATION messages are sent using "low" priority at the data link layer. This can lead to message loss or truncation when preempted by other "high" priority messages. A receiving layer 3 entity shall detect APDU truncation if an APPLICATION INFORMATION message is received carrying an APDU or APDU segment that is shorter than indicated by the length indicator for the APDU Data IE. This test is reliable because preemption in the data link layer guarantees that at least the first 2*N201 octets of any truncated message will be reliably transferred.

An APPLICATION INFORMATION transfer error shall be detected due to any of the following:

a) Receipt of a truncated APDU or APDU segment.

b) While performing APDU reassembly:

– receipt of any other layer 3 message defined to use SAPI 0 on the main DCCH;

– receipt of an APDU or APDU segment indicating "First or Only Segment";

– expiration of the reassembly timer (if supported).

c) While not performing APDU reassembly, receipt of an APDU segment indicating "not First or only segment".

d) Detection of any other error for a received message as defined in clause 8.

If APDU reassembly was in process when the error occurred, the receiving layer 3 entity shall discard the partially reassembled APDU and reprocess any received APDU or APDU segment that caused the error provided not an error defined in clause 8. In all other cases, any received APDU or APDU segment shall be discarded.

3.4.22 RR procedures related to packet resource establishment while in dedicated mode

The establishment of a packet resource is supported by procedures on the main DCCH when the mobile station is in dedicated mode. The procedures are only applicable to a mobile station supporting DTM with GPRS or EGPRS. The procedures are optional for the network.

These procedures constitute a complement to the corresponding procedures for temporary block flow establishment using CCCH or PCCCH while in idle mode defined in 3GPP TS 04.18 and 3GPP TS 04.60, respectively.

The packet request procedure is initiated by the MS and it is described in sub-clause 3.4.22.1. The packet notification procedure is initiated by the network and it is described in sub-clause 3.4.22.2. The packet downlink assignment is initiated by the network and it is described in sub-clause 3.4.22.3.

3.4.22.1 Packet request procedure while in dedicated mode

The packet request procedure using the main DCCH may be used to establish a packet resource to support the transfer of LLC PDUs in the direction from the mobile station to the network.

3.4.22.1.1 Entering the dual transfer mode

While in dedicated mode, the establishment of an uplink packet resource may be initiated by the RR entity of the mobile station using the packet request procedure. The procedure is triggered by a request from upper layers to transfer an LLC PDU; see 3GPP TS 24.007. The request from upper layers specifies:

– TLLI;

– radio priority;

– RLC mode associated with the packet transfer;

– LLC frame type;

– establishment cause;

– QoS information for the requested packet session; and

– optionally, the PFI.

Upon such a request, the RR entity of the mobile station:

– if access to the network is allowed (sub-clause 3.4.22.1.1.1), it initiates the packet request procedure as defined in sub-clause 3.4.22.1.1.2;

– otherwise, it rejects the request.

If the request from upper layers indicates any signalling procedure the acknowledged RLC mode shall be used.

3.4.22.1.1.1 Permission to access the network

Access to the network is allowed:

– if dual transfer mode is supported in the cell.

NOTE: belonging to an authorised access class or special class, radio priority level and LSA permission are not considered since they only apply to a mobile station in idle mode.

3.4.22.1.1.2 Initiation of establishment of the packet request procedure

The mobile station initiates the establishment the packet resource by sending a DTM REQUEST message on the main DCCH.

The DTM REQUEST message contains:

– TLLI;

– Channel Request Description;

– Packet establishment cause which indicates, as applicable, a request to send user data, cell update, page response or a mobility management message; and

– PFI, if the network indicates that it supports packet flow procedures (see 3GPP TS 04.60) and a PFC exists for the LLC data to be transferred.

Having sent the DTM REQUEST message, the mobile station starts timer T3148.

3.4.22.1.1.3 Answer from the network

3.4.22.1.1.3.1 Packet assignment

On receipt of a DTM REQUEST message the network may allocate an uplink packet resource. The packet uplink resource is assigned to the mobile station in one of the DTM assignment messages:

– DTM ASSIGNMENT COMMAND; or

– PACKET ASSIGNMENT.

These messages are sent in acknowledged mode on the main DCCH. If frequency hopping is applied, the mobile station shall use the cell allocation defined for the cell to decode the mobile allocation.

The allocation of the uplink packet resource may imply the reallocation of the resource for the RR connection. In this case, the DTM ASSIGNMENT COMMAND message is used and the timer T3107 is started on the network side. The DTM ASSIGNMENT COMMAND message shall not be used to change to a dependent configuration.

When sending the DTM ASSIGNMENT COMMAND message on the network side, and when receiving it on the mobile station side, all transmission of signalling layer messages except for those RR messages needed for this procedure and for abnormal cases is suspended until resumption is indicated. These RR messages can be deduced from sub-clauses 3.4.22.1 and 8.8 Radio Resource management.

The PACKET ASSIGNMENT message is only used when the packet resource is a PDCH and no reallocation of the RR connection is needed.

On receipt of:

– DTM ASSIGNMENT COMMAND message; or

– PACKET ASSIGNMENT message;

the mobile station shall stop T3148.

If the received DTM ASSIGNMENT COMMAND or PACKET ASSIGNMENT message includes uplink packet resources, the mobile station shall proceed with the packet access. If, in addition, the received DTM ASSIGNMENT COMMAND or PACKET ASSIGNMENT message includes concurrent downlink packet resources, the mobile station shall also obey the packet downlink assignment. If the received message includes downlink packet resources and no uplink packet resources, the mobile station shall abort the packet access procedure and proceed with the procedure specified in sub-clause 3.4.22.3, and then attempt an establishment of uplink TBF, using the applicable procedure specified in 3GPP TS 04.60.

Upon receipt of the DTM ASSIGNMENT COMMAND message, the mobile station initiates a local end release of link layer connections, disconnects the physical channels, commands the switching to the assigned channel and initiates the establishment of lower layer connection (this includes the activation of the channel, their connection and the establishment of the main signalling link).

If the channel mode to be applied corresponds to an initial assignment of a multi-rate speech codec, the DTM ASSIGNMENT COMMAND message shall contain the MultiRate Configuration IE, which defines the set of codec modes and related information to use on the new channel.

If the assignment is related to an assignment from a multi-rate speech codec to a multi-rate speech codec, the MultiRate Configuration IE shall be included in the DTM ASSIGNMENT COMMAND message in the case of full rate to half rate change. If not included in this case, the mobile station shall behave as if the MultiRate Configuration IE was inconsistent. If not included in other cases, the MS shall use on the new channel the AMR configuration it was using on the old channel when it received the DTM ASSIGNMENT COMMAND message.

3.4.22.1.1.3.2 RR reallocation only

If the mobile station receives an ASSIGNMENT COMMAND or HANDOVER COMMAND message during the packet access procedure, the mobile station shall abort the packet access procedure, stop timer T3148 and proceed with the channel assignment procedure as specified in sub-clause 3.4.3 or the handover procedure as specified in sub-clause 3.4.4. The mobile station shall then attempt an establishment of uplink TBF, using the procedure specified in sub-clause 3.4.22.

If the mobile station receives a CHANNEL RELEASE message during the packet access procedure, the mobile station shall abort the packet access procedure, stop timer T3148 and proceed with the RR connection release procedure as specified in sub-clause 3.4.13. The mobile station shall then attempt an establishment of uplink TBF.

If the mobile station receives an INTER SYSTEM TO UTRAN HANDOVER COMMAND message during the packet access procedure, the mobile station shall abort the packet access procedure, stop timer T3148 and proceed with the handover to UTRAN procedure as specified in sub-clause 3.4.4a.

3.4.22.1.1.3.3 Packet request rejection

If the network cannot allocate the requested packet resource it may send the mobile station a DTM REJECT message in acknowledged mode on the main DCCH. This message contains a wait time ("wait indication" information element).

On receipt of the DTM REJECT message, the mobile station stops T3148, notifies upper layers of a packet resource establishment failure and starts timer T3142 with the indicated value.

The mobile station is not allowed to make a new attempt for packet access in the same cell until T3142 expires. The value of the wait indication (i.e. T3142) relates to the cell from which it was received.

3.4.22.1.1.4 Packet request completion

The completion of the packet request procedure depends on the actual assignment message used by the network:

– When the network sends a DTM ASSIGNMENT COMMAND message (i.e. reallocation of the CS resource is required), after the main signalling link is successfully established, the mobile station returns an ASSIGNMENT COMPLETE message, specifying cause "normal event", to the network on the main DCCH. The packet request procedure is completed for the mobile station when the ASSIGNMENT COMPLETE message is sent and for the network when it is received. The network then stops timer T3107. The sending of the ASSIGNMENT COMPLETE message on the mobile station side and its receipt on the network side allow the resumption of the transmission of signalling layer messages other than those belonging to RR management.

– When the network sends a PACKET ASSIGNMENT message, the packet request procedure is completed for the network when assignment message is sent and for the mobile station when it is received.

When the packet request procedure is completed, the mobile station has entered the dual transfer mode.

3.4.22.1.1.5 Abnormal cases

If a failure occurs on the mobile station side before the packet request procedure is completed, all the allocated packet resources are released, the mobile station remains on the current channel and upper layers are notified (packet resource establishment failure).

a) If a DTM ASSIGNMENT COMMAND message indicates resources in a non-supported frequency band.

b) If the information available in the mobile station after the reception of a DTM ASSIGNMENT COMMAND or PACKET ASSIGNMENT message does not satisfactorily define uplink packet resources or concurrent uplink and downlink packet resources if both were included in the message.

c) If a DTM ASSIGNMENT COMMAND message includes a mobile allocation or a frequency list that indexes frequencies in more than one frequency band.

d) If a DTM ASSIGNMENT COMMAND or PACKET ASSIGNMENT message assigns resources not compliant with the multislot capabilities of the mobile station.

e) If the mobile station has no current CA and if it needs a CA to analyse the DTM ASSIGNMENT COMMAND message.

f) If the DTM ASSIGNMENT COMMAND message instructs the mobile station to use a channel description or mode that it does not support.

g) If the DTM ASSIGNMENT COMMAND or PACKET ASSIGNMENT message does not include any uplink or downlink packet resources.

h) At expiry of timer T3148.

i) If the DTM ASSIGNMENT COMMAND message includes a Channel Mode IE indicating multi-rate speech codec but the Multi-Rate configuration IE is missing and no old multi-rate configuration exists.

j) If the DTM ASSIGNMENT COMMAND message includes a Channel Mode IE indicating multi-rate speech codec and the possibly included Multi-Rate configuration IE is inconsistent.

The MultiRate Configuration IE shall be considered as inconsistent by the mobile station if:

– the active set does not include any codec mode or the active set includes more than four codec modes; or

– one or more codec modes of the active codec set are not supported by the assigned channel; or

– the threshold and hysteresis values are not set according to requirements given in 3GPP TS 05.09.

If the mobile station received a DTM ASSIGNMENT COMMAND message before the packet resource establishment failure was detected, the mobile station shall return a DTM ASSIGNMENT FAILURE message with one of the following corresponding cause values:

a) In case of abnormal case a) above, "frequency not implemented";

b) In case of abnormal case b) above, "protocol error unspecified";

c) In case of abnormal case c) above, "frequency not implemented";

d) In case of abnormal case d) above, "channel mode unacceptable";

e) In case of abnormal case e) above, "no cell allocation available";

f) In case of abnormal case f) above, "channel mode unacceptable";

g) In case of abnormal case g) above, "protocol error unspecified";

h) In case of abnormal case i) above, "channel mode unacceptable"; or

i) In case of abnormal case j) above, "channel mode unacceptable".

In addition:

– If the network commands the mobile station to reallocate the RR connection and the establishment of the main DCCH fails, all the allocated packet resources are released; the mobile station shall revert to the old channel, trigger the establishment of the main DCCH and send a DTM ASSIGNMENT FAILURE message on the main DCCH with cause value "lower layer failure".

– If a lower layer failure happens while attempting to connect back to the old channel, the radio link failure procedure is applied (see sub-clause 3.4.13.2).

When receiving the DTM ASSIGNMENT FAILURE message, the network stops T3107.

On the network side, if timer T3107 elapses before either the ASSIGNMENT COMPLETE message has been received on the new channel or an DTM ASSIGNMENT FAILURE message is received on the old channel; the old channel and the new channel are released. Unless the mobile station has re-established the call, all contexts related to the connections with that mobile station are cleared.

On the network side, lower layer failures occurring on the old channel after the sending of the DTM ASSIGNMENT COMMAND message are ignored. Lower layer failures occurring after the receipt of the SABM frame on the new main DCCH are treated following the general rules (see sub-clause 3.5.2).

3.4.22.2 Packet notification procedure in dedicated mode

The packet notification procedure is initiated by the RR entity of the network side. It is triggered by a page request from the GMM sublayer, see 3GPP TS 24.007.

3.4.22.2.1 Packet notification initiation by the network

The network initiates the packet notification procedure by sending the mobile station a PACKET NOTIFICATION message on the main DCCH.

The network shall not send the PACKET NOTIFICATION message to a mobile station that does not support dual transfer mode operation. If a mobile station not supporting dual transfer mode receives this message, it shall ignore it and remain in dedicated mode.

3.4.22.2.2 Packet notification response

Upon receipt of the PACKET NOTIFICATION message, the RR sublayer of the mobile station indicates the receipt of a packet paging request to the GMM sublayer; see 3GPP TS 24.007.

3.4.22.3 Packet downlink assignment in dedicated mode

The packet downlink assignment procedure in dedicated mode may be used to establish a packet resource to support the transfer of LLC PDUs in the direction from the network to the mobile station.

This procedure is only applicable to a mobile station in dedicated mode and with no TBF allocated. If the mobile station already has an ongoing TBF, the establishment of the downlink packet resource is performed on the PACCH; see 3GPP TS 04.60.

The establishment of a downlink packet resource is initiated by the RR entity on the network side using the packet downlink assignment procedure in dedicated mode. The procedure is triggered by a request from upper layers to transfer an LLC PDU; see 3GPP TS 24.007. The request from upper layers specifies a QoS profile, an RLC mode, DRX parameters and an MS classmark associated with the packet transfer.

3.4.22.3.1 Initiation of the packet downlink assignment procedure in dedicated mode

The network initiates the packet downlink assignment procedure in dedicated mode by sending a DTM assignment message (i.e. DTM ASSIGNMENT COMMAND or a PACKET ASSIGNMENT) in acknowledged mode on the main DCCH.

When sending the DTM ASSIGNMENT COMMAND message on the network side, and when receiving it on the mobile station side, all transmission of signalling layer messages except for those RR messages needed for this procedure and for abnormal cases is suspended until resumption is indicated. These RR messages can be deduced from sub-clause 3.4.22.3 and sub-clause 8.8 Radio Resource management.

The allocation of the downlink packet resource may imply the reallocation of the resource for the RR connection. In this case, the DTM ASSIGNMENT COMMAND message is used and the timer T3107 is started on the network side. The DTM ASSIGNMENT COMMAND message shall not be used to change to a dependent configuration.

The network shall not send any of the DTM assignment messages to a mobile station that does not support dual transfer mode operation. If a mobile station not supporting dual transfer mode receives any of these messages, it shall ignore it and remain in dedicated mode.

Upon receipt of the DTM ASSIGNMENT COMMAND message, the mobile station initiates a local end release of link layer connections, disconnects the physical channels, commands the switching to the assigned channel and initiates the establishment of lower layer connection (this includes the activation of the channel, their connection and the establishment of the main signalling link).

If the channel mode to be applied corresponds to an initial assignment of a multi-rate speech codec, the DTM ASSIGNMENT COMMAND message shall contain the MultiRate Configuration IE, which defines the set of codec modes and related information to use on the new channel.

If the assignment is related to an assignment from a multi-rate speech codec to a multi-rate speech codec, the MultiRate Configuration IE shall be included in the DTM ASSIGNMENT COMMAND message in the case of full rate to half rate change. If not included in this case, the mobile station shall behave as if the MultiRate Configuration IE was inconsistent. If not included in other cases, the MS shall use on the new channel the AMR configuration it was using on the old channel when it received the DTM ASSIGNMENT COMMAND message.

3.4.22.3.2 Packet downlink assignment completion

The completion of the packet downlink assignment procedure while in dedicated mode depends on the actual assignment message used by the network:

– When the network sends a DTM ASSIGNMENT COMMAND message (i.e. reallocation of the RR connection is required), after the main signalling link is successfully established, the mobile station returns an ASSIGNMENT COMPLETE message, specifying cause "normal event", to the network on the main DCCH. The packet downlink assignment procedure is completed for the mobile station when the ASSIGNMENT COMPLETE message is sent and for the network when it is received. The network then stops timer T3107. The sending of the ASSIGNMENT COMPLETE message on the mobile station side and its receipt on the network side allow the resumption of the transmission of signalling layer messages other than those belonging to RR management.

– When the network sends a PACKET ASSIGNMENT message, the packet downlink assignment procedure is completed for the network when assignment message is sent and for the mobile station when it is received.

3.4.22.3.3 Abnormal cases

If a failure occurs on the mobile station side before the packet downlink assignment procedure is completed (packet establishment failure), all the allocated packet resources are released and the mobile station remains on the current channel.

In the following cases a packet resource establishment failure has occurred:

a) If a DTM ASSIGNMENT COMMAND message indicates packet resources in a non-supported frequency band.

b) If the information available in the mobile station after the reception of a DTM ASSIGNMENT COMMAND or PACKET ASSIGNMENT message does not satisfactorily define downlink packet resources.

c) If a DTM ASSIGNMENT COMMAND message includes a mobile allocation or a frequency list that indexes frequencies in more than one frequency band.

d) If a DTM ASSIGNMENT COMMAND or PACKET ASSIGNMENT message assigns resources not compliant with the multislot capabilities of the mobile station.

e) If the mobile station has no current CA and if it needs a CA to analyse the DTM ASSIGNMENT COMMAND message.

f) If the DTM ASSIGNMENT COMMAND message instructs the mobile station to use a channel description or mode that it does not support.

g) If the DTM ASSIGNMENT COMMAND or PACKET ASSIGNMENT message does not include any downlink packet resources, or if it includes uplink packet resources.

h) If the DTM ASSIGNMENT COMMAND message includes a Channel Mode IE indicating multi-rate speech codec but the Multi-Rate configuration IE is missing and no old multi-rate configuration exists.

i) If the DTM ASSIGNMENT COMMAND message includes a Channel Mode IE indicating multi-rate speech codec and the possibly included Multi-Rate configuration IE is inconsistent.

The MultiRate Configuration IE shall be considered as inconsistent by the mobile station if:

– the active set does not include any codec mode or the active set includes more than four codec modes; or

– one or more codec modes of the active codec set are not supported by the assigned channel; or

– the threshold and hysteresis values are not set according to requirements given in 3GPP TS 05.09.

If the mobile station received a DTM ASSIGNMENT COMMAND message before the packet resource establishment failure was detected, the mobile station shall return a DTM ASSIGNMENT FAILURE message with one of the following corresponding cause values:

a) In case of abnormal case a) above, "frequency not implemented";

b) In case of abnormal case b) above, "protocol error unspecified";

c) In case of abnormal case c) above, "frequency not implemented";

d) In case of abnormal case d) above, "channel mode unacceptable";

e) In case of abnormal case e) above, "no cell allocation available";

f) In case of abnormal case f) above, "channel mode unacceptable";

g) In case of abnormal case g) above, "protocol error unspecified";

h) In case of abnormal case h) above, "channel mode unacceptable"; or

i) In case of abnormal case i) above, "channel mode unacceptable".

In addition:

– If the network commands the mobile station to reallocate the RR connection and the establishment of the main DCCH fails, all the allocated packet resources are released; the mobile station shall revert to the old channel, trigger the establishment of the main DCCH and send a DTM ASSIGNMENT FAILURE message on the old main DCCH with cause value "lower layer failure".

– If a lower layer failure happens while attempting to connect back to the old channel, the radio link failure procedure is applied (see sub-clause 3.4.13.2).

When receiving the DTM ASSIGNMENT FAILURE message, the network stops T3107.

On the network side, if timer T3107 elapses before either the ASSIGNMENT COMPLETE message has been received on the new channel or an DTM ASSIGNMENT FAILURE message is received on the old channel; the old channel and the new channel are released. Unless the mobile station has re-established the call, all contexts related to the connections with that mobile station are cleared.

On the network side, lower layer failures occurring on the old channel after the sending of the DTM ASSIGNMENT COMMAND message are ignored. Lower layer failures occurring after the receipt of the SABM frame on the new main DCCH are treated following the general rules (see sub-clause 3.5.2).

3.4.22.4 Modification of packet resources while in DTM

When the mobile station is in dual transfer mode, the network or mobile station may wish to modify the allocated packet resource. When the mobile station has an ongoing TBF, the procedures described in 3GPP TS 04.60 shall be used. When the main DCCH is the only packet resource that the mobile station has, the RR procedures related to packet resource establishment while in dedicated mode shall be used.

3.4.23 RR procedures related to packet resource maintenance while in dual transfer mode

Once the mobile station enters the dual transfer mode, the existent procedures apply (see 3GPP TS 04.60). Some exceptions to the existent procedures while in dedicated mode are:

– When all packet resources have been released (or aborted), the mobile station returns to dedicated mode.

– When the mobile station is in dual transfer mode, it shall ignore any RR-CELL CHANGE ORDER or PACKET CELL CHANGE ORDER message and shall remain in dual transfer mode.

– When the mobile station receives a HANDOVER COMMAND or an ASSIGNMENT COMMAND message, it shall abandon the packet resource immediately, enter dedicated mode and perform the handover or assignment procedure, respectively.

– As stated in 3GPP TS 05.08, no GPRS measurement reporting is performed.

The DTM ASSIGNMENT COMMAND message is used by the network to reallocate the DTM resources assigned to a mobile station when the CS channel needs to be reallocated. All of the ongoing TBFs shall be addressed by the DTM ASSIGNMENT COMMAND message. The procedures in 3GPP TS 04.60 shall be used to establish an additional TBF or to release an ongoing TBF.

In case the network has to change the frequency parameters, the frequency redefinition procedure shall be used (see sub-clause 3.4.5).

In case the network has to change the channel mode of the traffic channel, the channel mode modify procedure shall be used (see sub-clause 3.4.6).

The mobile station remains in dual transfer mode until the RR connection or all the packet resources are released.

3.4.24 RR procedures related to packet resource release while in dual transfer mode

The release of a TBF shall follow the procedures in 3GPP TS 04.60.

In the case of the release of the RR connection while in dual transfer mode, the mobile station shall abandon the packet resource and, once in idle mode and packet idle mode, it may start a new establishment as described in 3GPP TS 04.60.

3.4.25 GPRS suspension procedure

3.4.25.1 General

This procedure enables the network to suspend GPRS services packet flow in the downlink direction. The support of this procedure is conditional to the support of GPRS by the mobile station.

When a mobile station which is IMSI attached for GPRS services (see 3GPP TS 24.008) enters the dedicated mode, and when the mobile station limitations make it unable to handle both dedicated mode and either packet idle mode or packet transfer mode simultaneously, the mobile station shall perform the GPRS suspension procedure.

The RR sublayer of the mobile station shall indicate a RR GPRS suspend condition to the MM sublayer, see 3GPP TS 24.008.

3.4.25.2 MS in class B mode of operation

The GPRS suspension procedure shall be used to suspend GPRS services when the mobile station is in class B mode of operation and a circuit switched service is initiated. It is also used when a mobile station in CS/PS mode of operation in UTRAN reverts to class B mode of operation in GSM.

The GPRS suspension procedure is initiated by the mobile station by sending a GPRS SUSPENSION REQUEST message with the appropriate suspension cause. This can be done as early as possible after access but shall be done after sending a CLASSMARK CHANGE message.

3.4.25.3 Dual transfer mode not supported

The GPRS suspension procedure shall be used to suspend GPRS services:

a) When the mobile station in a class A mode of operation is handed over to a cell where the support of Class A mode of operation is not possible (e.g. a DTM mobile station entering a cell not supporting DTM).

b) When the GPRS attached mobile station is in a cell that does not support DTM and a circuit switched service is initiated.

In case a), when the mobile station concludes that DTM is not supported in the new cell after the handover procedure is completed, it shall initiate the GPRS suspension procedure by sending a GPRS SUSPENSION REQUEST message with the suspension cause set to "DTM not supported in the cell".

In case b), the GPRS suspension procedure is initiated by the mobile station by sending a GPRS SUSPENSION REQUEST message with the suspension cause set to "DTM not supported in the cell". This can be done as early as possible after access but shall be done after sending a CLASSMARK CHANGE message.

3.4.26 GPRS Transparent Transport Procedure

While in dedicated mode, upper layers in the mobile station or in the network may request the transport of GPRS information transparently over the radio interface. This procedure is only applicable when:

– the information from upper layers is signalling information; and

– the GTTP length of the message is below the maximum indicated by the network.

In any other case, the RR procedures related to packet resource establishment while in dedicated mode apply.

The information from upper layers shall be carried inside the GTTP Information message. The GTTP Information message contains:

– the TLLI of the MS; and

– the LLC PDU.

The GTTP messages are sent using "normal" priority at the data link layer.