8 Functions common to all interfaces

07.013GPPGeneral on Terminal Adaptation Functions (TAF) for Mobile Stations (MS)TS

8.1 Synchronization of the Traffic Channel

As long as there is no connection between the traffic channel and the interface to the TE this interface must be terminated in the appropriate way.

Prior to exposing the traffic channel of a GSM PLMN connection to transmission of user data, the controlling entities of the connection have to assure of the availability of the traffic channel(s). This is done by the so called synchronization process:

– starting on the indication of "physical connection established" resulting from the PLMN inherent outband signalling procedure. This indication is given on reception of the message CONNECT in case of MOC, on reception of the message CONNACK in case of MTC and on reception of the message MODIFY COMPLETE in case of in-call modification.

– ending by indicating the successful execution of this process to the controlling entity, which then takes care of the further use of the inband information (data, status).

With respect to the TAF for the transparent bearer capability support the synchronization procedure with the channel codings 2.4, 4.8 and 9.6 kbit/s is as follows:

– sending of synchronization pattern 1/OFF (all data bits "1" / all status bits "OFF", all E-bits "1") to the IWF. In multislot transparent operation, the synchronisation pattern sent is 1/OFF with the exception of the bit positions S1, first X, S3, and S4 which contain the substream number and multiframe alignment pattern (Ref. GSM TS 04.21);

– searching for detection of the synchronization pattern received from the IWF, and in multislot operation, also searching for the multiframe alignment pattern “0000 1001 0110 0111 1100 0110 1110 101” (Ref. to GSM 04.21) in bit position S4 and substream numbers in bit positions S1, first X, and S3. The value of the bits E4-E7 shall not be checked;

– holding CT106, 107 and 109 in the OFF condition;

With respect to the TAF for the transparent bearer capability support the procedure with the TCH/F14.4 is as follows:

– sending of synchronization pattern 1/OFF (all data bits "1" / status bits in M2 "OFF") to the network in the multiframe structure with the multiframe alignment pattern pattern “0000 1001 0110 0111 1100 0110 1110 101” in the M1 (Ref. to GSM TS 4.21) and, in a multislot case, sending substream numbers in the bit M2

– searching for the detection of the multiframe alignment pattern “0000 1001 0110 0111 1100 0110 1110 101” (Ref. to GSM 04.21) in the bit M1 originating from the network, and, in a multislot case, searching for substream numbers in the bit M2. (Any 5 bit sequence in the multiframe alignment pattern is unique, i.e. the multiframe alignment can take place by the recognition of five successive S1 bits.)

– holding CT106, 107 and 109 in the OFF condition;

When the synchronisation pattern and, in case of multislot operation or TCH/F14,4, the multiframe alignment pattern from the IWF have been recognized as a steady state (see note 1) the TAF continues sending the synchronization patterns to the IWF unless a timer T (=500ms) expires.

NOTE 1: – An idle frame sent by the BSS and received by the MS has the same pattern as the synchronization pattern 1/OFF.

– At the moment when the message CONNECT (MOC) or CONNACK (MTC) is received at the MS, it is guarantied that this pattern is received from the MSC/IWF with the exception of a loss of frame synchronization on the Abis interface.

– The handling of frame stealing in case of 2400 bit/s full rate data channels is implementation dependent.

From this time, after the expiration of the timer T of each allocated traffic channel for the call, the filtering process according to section 8.2 applies and the information on the receiving lines CT106 and CT109 (M2 bit in the TCH/F14.4 case, ref to GSM 04.21) from the IWF are directly mapped to the respective sending lines. The condition on CT107 will be changed from "OFF" to "ON", the data bits received from the IWF are mapped to CT104, and CT103 is mapped to the data bits sent towards the IWF.

During the synchronization process described above i.e. while the synchronization pattern is being sent by the MT, the MT will not send the V.110 frame structure to the ISDN terminal. Once the timer T of each traffic channel(s) allocated for the call expires the synchronization pattern will continue to be transmitted from the MT to the IWF, however, the MT will start sending the V.110 frames received from the IWF to the ISDN terminal. The MT will start looking for the ISDN frame alignment to be received from the ISDN terminal. On recognizing frame alignment the MT will cease sending its synchronization pattern to the IWF and connect the ISDN terminal through to the IWF. In case of multislot operation or TCH/14.4 the MT shall adapt the data stream as defined in GSM TS 04.21.

With respect to the TAF for non-transparent bearer capability support the synchronization procedure is as follows:

– receiving V.110 frames on all allocated traffic channels for the call

– initiating the RLP link establishment by sending a RLP-SABM across the radio interface.

– holding CT106, 107, 109 in the OFF condition.

When the RLP link has been established, CT107 will be changed from "OFF" to "ON". From this time the information from/to the RLP, including status changes, will be mapped by the L2R entity applicable to the particular bearer capability. The MT will not send V.110 frame structure to the ISDN terminal and will not start looking for ISDN frame alignment to be received from the ISDN terminal unless the RLP link has been established. On recognizing frame alignment the information from/to the RLP will be mapped by the L2R entity.

It should be noted that in a GSM PLMN V.-series and X.-series interfaces are only supported in full duplex mode. Thus the call control phase can be mapped almost completely to the signalling procedure (the S-bits during the call control phase are irrelevant). However, the "ready for data" condition (i.e. CT 106/109, in the case of V.-series interface, and I-circuit, in the case of X.-series interface) is derived directly from the traffic channel (see also filtering of channel information).

8.2 Filtering of Channel Control Information

8.2.1 General

The DTEs taken into account for the PLMN at the MS side conform to CCITT’s DTE/DCE interface specifications, which assume basically an error-free environment, i.e.

– limited distance, point-to-point local interconnection of the interface circuits for data and status;

– steady state signalling.

The envisaged use of these DTEs in the PLMN environment leads to the exposure of these "interconnections" to the PLMN radio channel. To assure proper operation even under these conditions appropriate measures have to be taken. In the non transparent case the RLP satisfies the requirement for both data and status lines.

In the transparent case the

– data line aspects have to be dealt with end-to-end between the users, while

– status line aspects are of concern to the network, which are dealt with in the following.

8.2.2 Filtering process to be applied

Filtering of channel control information is only relevant at the MS side in the transparent mode of operation. By applying filtering measures the condition of a DTE/DCE control interchange circuit, for which the DTE constitutes the information sink, will be preserved until another condition is signalled for an "integration time" period by the channel control information (status bits) of the rate adaptation scheme.

The filtering mechanism is understood to reside between the rate adaptation function (information source) and the DTE (information sink). It receives the unfiltered condition of the respective control interchange circuit set according to the actual sequential appearance of the individual associated status bit and forwards the filtered condition to the DTE.

The filtering process starts when the traffic channel synchronization ends with the expiry of timer T.

V.-series interface

CT 106

In the transparent mode the remote inband control of this circuit is needed to support a modem retrain procedure.

OFF-ON transition at the MS will authorize the DTE to send data; if wrongly set, loss of data may occur.

ON-OFF transition at the MS will cause the DTE to cease transmitting data; set wrongly may impair the performance in connection usage.

CT 109

In the transparent mode the remote inband control of this circuit is needed to:

– trigger the interpretation of received data;

– indicate to the DTE the state of the connection.

OFF-ON transition at the MS will authorize the DTE to rely on the condition of the received data interchange circuit, set wrongly may cause receipt of wrong data, while setting late may cause loss of data.

ON-OFF transition at the MS:

– will cause the DTE to cease receiving data;

– may initiate release of the connection during a data phase by the DTE giving an ON-OFF transition on circuit 108/2.

Setting this condition wrongly may cause loss of data and potentially release the connection.

X.-series interface

I-circuit

The OFF-ON transition of this circuit in connection with the appropriate conditions of the other interchange circuit will indicate the "ready for data" status of the connection. As received data may commence immediately following this status change, the delay in conveying this condition shall be kept as short as possible.

As a clear request/indication will be directly mapped to the PLMN outband signalling the ON-OFF integration time should be rather long.

Filtering mechanism

A filtering mechanism shall be provided by an integration process on those SB and X bits carrying status information in the V.110 frame or in the multiframe structure. The integration periods applied are:

V-series

Transition

Integration

Status

period

stream

CT 106

Off-On

1 s

X

CT 106

On-Off

1 s

X

CT 109

Off-On

200 ms

SB

CT 109

On-Off

5 s

SB

X-series

Transition

Integration

Status

period

stream

I-circuit

Off-On

40 ms

SB

I-circuit

On-Off

5 s

SB

The integration process shall ensure that the interchange circuits do not change state in response to spurious transitions of the status bits during the integration period.

The integration process shall operate reliably with error characteristics as specified in GSM 05.05.

8.3 Terminal Compatibility Decision

The establishment of a mobile terminated connection depends on a positive decision on the terminal compatibility. The Mobile Station (MS) contributes to this process by performing (depending on the individual call set-up condition):

– a compatibility check;

– the selection of the appropriate terminal function; and

– the indication of compatibility requirements to the PLMN;

initiated by a call set-up request from the PLMN. The aforementioned functions shall be carried out as follows.

8.3.1 Compatibility Check

Annex B of GSM 04.08 applies, particularly paragraphs B.3, B.3.1 and B.3.2. As regards the therein mentioned user-to-user compatibility checking the following applies:

When the calling user requests a service with user-to-user compatibility significance indicated by the presence of HLC and LLC information element in the call set-up request, the MS shall check that the service supported by the called user matches concerning the contents of the HLC/LLC information element. If a mismatch is detected, then the MS shall reject the offered call using the cause No.88 "Incompatible Destination".

8.3.2 Selection of Appropriate Terminal Function

The MS shall select the appropriate terminal functions following a positive result of the compatibility check and/or forwarding the indication of compatibility requirements to the PLMN.

8.3.3 Indication of Compatibility Requirements to the PLMN

8.3.3.1 Indication in case of Mobile terminating calls

In support of:

– PSTN originated calls, and

– ISDN originated calls using 3.1 kHz audio Bearer Capability (BC), as well as

– ISDN originated calls using unrestricted digital Bearer Capability but not specifying all parameters for deducing a Bearer Service.

Mobile specific requirements to be dealt with in the Bearer Capability information element the call confirmed message has been introduced in the call control protocol (GSM 04.08). This also allows for renegotiation of specific parameters at the beginning of the connection set-up process. The specific parameters are:

a) mobile specific requirements:

– Connection element (transparent/non transparent);

– Structure (note 1);

– User information layer 2 protocol (note 1);

– Intermediate rate (note 2), (note 3);

– Modem Type (note 1), (note 3);

– User Rate (note 3);

– Compression ,

– Fixed network user rate, (note 3) (note 4)

– Other modem type, (note 3) (note 4)

– User initiated modification indication (note 4)

The following parameters are indicated by the MS to the network, only:

– Acceptable channel codings (note 5)

– Maximum number of traffic channels, (note 5)

– Wanted air interface user rate (note 6)

NOTE 1: This parameter is correlated with the value of the parameter connection element.

NOTE 2: For non-transparent services this parameter is correlated with the value of the parameter negotiation of intermediate rate requested.

NOTE 3: Modification of these parameters may be proposed by the MS. The Network may accept it or not.

NOTE 4: This parameter shall be included by the MS only in case it was received from the network.

NOTE 5: This parameter shall be included only in case the parameter ‘fixed network user rate’ is included.

NOTE 6: This parameter shall be included only for non-transparent services and in case the parameter ‘fixed network user rate’ is included.

b) requirements with effects at the partner terminal:

– Number of data bits;

– Number of stop bits;

– Parity.

The MS indicates the radio channel requirement in the call confirmed message. If the MS indicates the support of "dual" (HR and FR channels) the final decision, which radio channel is chosen, is done by the network in an RR message.

If the network proposes optional support of both transparent and non transparent connection elements but does not indicate a user information layer 2 protocol, the MS shall set the appropriate value, if choosing non transparent in the call confirmed message and out-band flow control is not requested.

Additionally the values of the parameters structure, modem type and intermediate rate have to be set in conformance with the values of the parameters radio channel requirements, negotiation of intermediate rate requested and connection element.

Section B.1.1.2 and table B.1 in the annex B describe the negotiation procedure. Annex B table B.4 describes the selection of the modem type and the dependence on the value of the parameter connection element. Annex B table B.4 describes the selection of the intermediate rate and user rate and their dependence upon the value of the NIRR parameter and the equipments capabilities.

The following MTC cases can be deduced from the individual call set-up request conditions

a) If the set-up does not contain a BC information element, the MS in the call confirmed message shall include any BC information (single or multiple BC-IE). In case of multiple BC-IEs one BC-IE must indicate the information transfer capability "speech".

b) If the set-up message contains a single BC-IE, the MS in the call confirm message shall use either a single BC-IE, if it wants to negotiate mobile specific parameter values, or, unless otherwise specified in annex B, no BC-IE, if it agrees with the requested ones.

c) If the set-up contains a multiple BC-IE, the MS in the call confirmed message shall use either a multiple BC-IE, if it wants to negotiate mobile specific parameter values, or, unless otherwise specified in annex B, no BC-IE, if it agrees with the requested ones. Alternatively a single BC-IE containing fax group 3 only shall be used if a multiple BC-IE requesting speech alternate fax group 3 is received and the MS is not able to support the speech capability. Annex B, table B.7, describes the negotiation rules.

If the BC-IE contains 3.1 kHz ex PLMN, the MS is allowed to negotiate all mobile specific parameter values listed above. If the BC-IE contains facsimile group 3, the MS is allowed to negotiate the connection element (transparent/non transparent) only. In any case, if the set-up message requests a "single service", the MS must not answer in the call confirmed message requesting a "dual service" and vice versa.

However, for dual services with repeat indicator set to circular (alternate) the MS may change the sequence of dual BC-IEs within the call confirmed message (preceded by the same value of the repeat indicator), if it wants to start with a different Bearer Capability than proposed by the network as the initial one.

In addition, the MS may propose to the network to modify User Rate, Modem Type and Intermediate Rate in the CALL CONFIRMED message. The network may accept or release the call.

If the BC-IE received from the network containes the parameters ‘fixed network user rate’, ‘other modem type’ and possibly the ‘user initiated modification’, the MS can either:

a) discard these parameters, or

b) include the possibly modified values for the "fixed network user rate" and "other modem type" in the BC-IE of the call confirmed message. The network might accept or reject the modified values. In this case the MS shall also include the parameters "maximum number of traffic channels" and "acceptable channel codings". Additionally for non-transparent services, the MS shall also include the parameters "wanted air interface user rate" and the "user initiated modification indication".

In case a),The MS shall use the fall-back bearer service indicated by the remaining parameters of the BC-IE on a singleslot configuration (ref GSM 04.21).

In case b), a singleslot configuration shall be used by the MS, in case the ‘maximum number of traffic channels’ is set to “1 TCH“ and the ‘user initiated modification indication’ is set either to “user initiated modification not required” or to “user initiated modification upto 1TCH may be requested”; otherwhise the MS shall use a multislot configuration (ref GSM 04.21).

In case the "acceptable channel codings" is indicated by the MS, the decision which channel coding is used is done by the network and indicated to the mobile station with an RR message. The "acceptable channel codings" parameter takes precedence over the "negotiation of intermediate rate requested" parameter for non-transparent services. Also the intermediate rate and user rate per traffic channel in a multislot configuration are not indicated by the "intermediate rate" and "user rate" parameters of the BC-IE, but depend on the chosen channel coding only.

If the parameters "fixed network user rate", "other modem type" were not included in the BC-IE received, or no BC-IE was received, the MS shall not include these parameters in the CALL CONFIRMED message (i.e. octets 6d, 6e and 6f, ref. to GSM 04.08).

8.3.3.2 Indication in case of Mobile originating calls

In support of mobile originating calls the values of BC-IE parameters are requested in the set-up message from the MS. If the MS indicates the support of both transparent and non transparent connection elements the network shall return its choice in the call proceeding message. The MS is not allowed to indicate support of both transparent and non transparent, if the MS also requests out-band flow control, i.e. it does not indicate a layer 2 protocol.

Additionally the value of the parameter modem type has to be set depending on the value of the parameter connection element as described in annex B, table B.4a.

The set-up message contains a single or multiple BC-IE. In case of multiple BC-IEs one BC-IE must indicate the information transfer capability "speech".

If the set-up message requests a "single service", the network must not answer in the call proceeding message requesting a "dual service" and vice versa. Alternatively the network shall answer with a single BC-IE containing fax group 3 if a multiple BC-IE requesting speech alternate fax group 3 is received but the network does not allow the use of this alternate service. Annex B, table B.7, describes the negotiation rules. If the MS requests a "dual service" the network is not allowed to change the sequence of the service.

If the set-up message is indicates that negotiation of intermediate rate is requested then the network shall behave as described in annex B, table B.4b.

Unless otherwise specified in annex B, if no BC-IE parameter needs negotiation it is up to the network if it sends a CALL PROC message (with or without a BC-IE) towards the MS or not.

For multislot and TCH/F14.4 operations the MS shall include an appropriate set of the parameters ‘fixed network user rate’, ‘other modem type’, ‘maximum number of TCH’ and ‘acceptable channel codings’ in the BC-IE of the SETUP message.In a non-transparent multislot operation, the MS shall also include the parameters ‘wanted air interface user rate’ and ‘user initiated modification indication’ in the BC-IE of the SETUP message. In a non-transparent TCH/F14.4 operation the MS shall also include the parameter ‘wanted air interface user rate’ It shall also set the other parameters of the BC-IE (i.e. ‘user rate’) to values identifying a fall-back bearer service. The fall-back bearer service shall be within the same bearer service group as the general bearer service. Depending on the network two situations can be distinguished:

a) The network supports the requested operation:

In this case the network must include the parameter ‘fixed network user rate’, ‘other modem type’ and possibly ‘user initiated modification’ in the BC-IE(s) of the CALL PROCEEDING message, irrespective whether or not they contain modified values or just a copy of the received ones.

The ‘acceptable channel codings’ indicated by the MS in the SETUP message takes precedence over the ‘negotiation of intermediate rate requested’ parameter for non-transparent services. The intermediate rate per traffic channel and the user rate per traffic channel is dependent on the chosen channel coding only. The chosen channel coding is indicated to the mobile station by the network with an RR message.

b) The network does not support the requested operation:

In this case the BC-IE of the CALL PROCEEDING message will not contain the parameters fixed network user rate’ and ‘other modem type’ or no BC-IE will be included in the CALL PROCEEDING message at all. The mobile station shall then discard the parameters ‘fixed network user rate’, ‘other modem type’, ‘maximum number of TCH’, ‘acceptable channel codings’ ‘wanted air interface user rate’ and ‘user initiated modification indication’ sent with the SETUP message and apply the fall-back bearer service.

In case a), a singleslot configuration shall be used by the MS, in case the ‘maximum number of traffic channels’ is set to “1 TCH“ and the ‘user initiated modification indication’ is set either to “user initiated modification not requested” or to “user initiated modification upto 1TCH may be requested”.

In case b), The MS shall use the fall-back bearer service indicated by the remaining parameters of the BC-IE on a singleslot configuration (ref GSM 04.21).

8.4 Test Loops

In principle, both V.-series and X.-series interfaces allow for an activation of local or remote test loops by the terminal (ref. CCITT V.54/X.150). A comprehensive solution of such test loops in a GSM system has to consider the special conditions of the interface between the terminal (part of the MS) and the transmission equipment (part of the modem pool of a particular IWF within the MSC). In addition, the impact of the radiolink is to be taken into account with respect to the test objectives. Due to those special conditions a GSM system is not capable to support remote test loops. It is an implementation choice to what extent the activation of local test loops by the terminal is supported in the MT.

8.5 Alternate speech/data and speech/facsimile group 3

These alternate services may be initiated by either V.25 bis or manual procedures. In the former case, standard call establishment procedures will apply. In the latter case, CT106, CT107, CT108.2 and CT109 are in the OFF condition.

Selection of the data phase (from the speech phase) will be by manual intervention via the MS causing ICM by means of CT108.2 going to ON condition. In case of dual data services (alternate speech/data or speech followed by data) the "Reverse call setup direction" information element of the modify message (determined by MMI) together with information about the initial call setup direction may be used to control the IWF modem (working as calling or answering modem). In case of alternate speech/facsimile refer to GSM 03.45. The ensuing data phase shall follow all the operational procedures as described in 07-series.

Selection of the speech phase (from the data phase) will be by manual intervention via the MS causing ICM (phone off-hook condition at the MT and data call end condition at the TE).

During the ensuing speech phases, CT107, CT106 and CT109 will be maintained in the OFF condition.

Subsequent re-selection of the data phase will be by manual intervention via the MS causing CT108.2 going to ON condition initiating ICM. At this point, re-synchronization will take place as described in section 8.1 above.

8.6 Multislot configuration spit/combine function

In multislot configurations using multiple parallel channels tha data flow is split into substreams between the Spit/Combine-function in the TAF and the network.

8.6.1 Non-transparent data

In non-transparent data operations the N(S)-numbering in the RLP-header is used for controlling the order of the data in the substreames (ref GSM 04.22).

8.6.2 Transparent data

In transparent multislot configurations status bits S1, S3 and the X-bit between the D12 and D13 are used for transferring substream numbering information. Ths S4-bit is used for frame synchronization between the parallel substreames (ref GSM 04.21).

Annex A (Informative):
List of Bearer Capability Elements

This annex lists the GSM Bearer Capability Elements which need to be provided on the Dm channel to support Terminal adaptation function to Interworking control procedures.

Elements and their Values:

Information Transfer Capability:

This element is relevant between the IWF and the fixed network

Values: – Speech

– Unrestricted Digital

– Group 3 Facsimile (note 1)

– 3.1 kHz Ex PLMN (note 2)

– Restricted Digital (note 3)

NOTE 1: Used for facsimile transmission, unrestricted digital between MT and IWF and 3.1 kHz audio from IWF towards the fixed network.

NOTE 2: unrestricted digital between MT and IWF and 3.1 kHz audio from IWF towards the fixed network.

NOTE 3: unrestricted digital between MT and IWF and restricted digital information from IWF towards the fixed network; this value is signalled in the “Other ITC” element, due to a lack of further code points in the “ITC” element.

Transfer Mode:

This element is relevant between MT and IWF

Values: – Circuit

– Packet

Structure:

This element is relevant between MT and IWF.

Values: – Service Data Unit Integrity (note 4)

– Unstructured (note 5)

NOTE 4: applicable for connection element "non transparent".

NOTE 5: applicable for connection element "transparent".

Configuration:

This element is relevant for a PLMN connection.

Values: – Point to point

Establishment:

This element is relevant for a PLMN connection.

Values: – Demand

Sync/Async:

This element is relevant between TE/TA and MT and between IWF and the fixed network.

Values: – Synchronous

– Asynchronous

Negotiation:

This element is relevant between MT and IWF.

Values: – In band negotiation not possible

User Rate:

This element is relevant between TE/TA and MT and between IWF and the fixed network, except in case the parameter FNUR is present.

Values: – 0.3 kbit/s

– 1.2 kbit/s

– 1200/75 bit/s

– 2.4 kbit/s

– 4.8 kbit/s

– 9.6 kbit/s

– 19.2 kbit/s (see note 6)

NOTE 6: This value cannot be signalled between MT and IWF, but it can be used according to the rules in GSM 09.07 (Table 6A, 6B) for such connections.

Intermediate Rate:

This element is relevant between MT and BSS and BSS and IWF

Values:

– 8 kbit/s

– 16 kbit/s

Network Independent Clock on Tx:

This element is relevant between TE/TA and MT in the transmit direction.

Values: – Not required

– Required

Network Independent Clock on Rx:

This element is relevant between TE/TA and MT in the receive direction.

Values: – Not accepted

– accepted

Number of Stop Bits:

This element is relevant between the TE/TA and MT and between IWF and fixed network in case of asynchronous transmission.

Values: – 1 bit

– 2 bit

Number of Data Bits Excluding Parity If Present:

This element is relevant between TE/TA and MT and between IWF and the fixed network in case of a character oriented mode of transmission.

Values: – 7 bit

– 8 bit

Parity Information:

This element is relevant between TE/TA and MT and between IWF and the fixed network for a character oriented mode of transmission.

Values: – Odd

– Even

– None

– Forced to 0

– Forced to 1

Duplex Mode:

This element is relevant between MT and IWF.

Values: – Full Duplex

Modem Type:

This element is relevant between the IWF and the fixed network in case of 3.1 kHz audio ex-PLMN information transfer capability.

Values: – V.21

– V.22

– V.22 bis

– V.23

– V.26 ter

– V.32

– autobauding type 1

– none

Radio Channel Requirement:

This element is relevant between MT and BSS

Values: – Full Rate support only Mobile Station

– Dual Rate support Mobile Station/Half Rate preferred

– Dual Rate support Mobile Station/Full Rate preferred

Connection Element:

This element is relevant between MT and IWF

Values: – Transparent

– Non Transparent

– both, Transparent preferred

– both, Non transparent preferred

User Information Layer 2 Protocol:

This element is relevant between TE/TA and MT and between IWF and the fixed network.

Values: – ISO 6429

– X.25

– X.75 layer 2 modified (CAPI)

– Character oriented Protocol with no Flow Control mechanism

Signalling Access Protocol:

This element is relevant between TE/TA and MT.

Values: – I.440/450

– X.21

– X.28, dedicated PAD, individual NUI

– X.28, dedicated PAD, universal NUI

– X.28, non dedicated PAD

– X.32

Rate Adaptation:

This element is relevant between IWF and the fixed network.

Values: – V.110/X.30

– X.31 flagstuffing

– no rate adaptation
– V.120 (note 7)

NOTE 7: – this value is signalled in the “Other Rate Adaption” elemement, due to a lack of further code points in the “Rate Adaption” element.

Coding Standard:

This element refers to the structure of the BC-IE defined in GSM 04.08.

Values: – GSM

User Information Layer 1 Protocol:

This element characterize the layer 1 protocol to be used between MT and BSS (Um interface) according to GSM 05.01.

Values: – default

Negotiation of Intermediate Rate requested:

This element is relevant between MT and BSS and BSS and IWF.

Values: – no meaning associated

– 6 kbit/s radio interface is requested for a full rate channel with a user rate up to

and including 4.8 kbit/s, non transparent service

Compression:

This element is relevant between MT and IWF.

Values: – compression possible/allowed

– compression not possible/allowed

Rate adaption header / no header:

This element is relevant between IWF and the fixed network. It is only applicable for V.120 rate adaptation.

Values: – Rate adaption header not included

– Rate adaption header included

Multiple frame establishment support in data link:

This element is relevant between IWF and the fixed network. It is only applicable for V.120 rate adaptation.

Values: – Multiple frame establishment not supported. Only UI frames allowed.

– Multiple frame establishment supported.

Mode of operation:

This element is relevant between IWF and the fixed network. It is only applicable for V.120 rate adaptation.

Values: – Bit transparent mode of operation

– Protocol sensitive mode of operation

Logical link identifier negotiation:

This element is relevant between IWF and the fixed network. It is only applicable for V.120 rate adaptation.

Values: – Default, LLI=256 only

– Full protocol negotiation (note 8)

NOTE 8: A connection over which protocol negotiation will be executed is indicated in the „In-band / out-band negotiation“ parameter.

Assignor / assignee:

This element is relevant between IWF and the fixed network. It is only applicable for V.120 rate adaptation.

Values: – Message originator is „default assignee“

– Message originator is „assignor only“

In-band / out-band negotiation:

This element is relevant between IWF and the fixed network. It is only applicable for V.120 rate adaptation.

Values: – Negotiation is done with USER INFORMATION messages on a temporary signalling connection

– Negotiation is done in-band using logical link zero.

Fixed network user rate, FNUR (Note 12)

This element is relevant between the IWF and the fixed network.

Values Fixed network user rate not aplicable (note 9)

9.6 kbit/s

14.4 kbit/s

19.2 kbit/s

28.8 kbit/s

38.4 kbit/s

48.0 kbit/s

56.0 kbit/s

64.0 kbit/s

NOTE 9: not used by currently specified services

Wanted air interface user rate, WAIUR (Note 12)

This element is relevant between the MT and the IWF

Values Air interface user rate not applicable (note 10)

9.6 kbit/s

14.4 kbit/s

19.2 kbit/s

28.8 kbit/s

38.4 kbit/s

43.2 kbit/s

57.6 kbit/s

interpreted by the network as 38.4 kbit/s (note 1)

NOTE 10: not used by currently specified services

Acceptable channel codings, ACC (Note 12)

This element is relevant between the MT and the IWF.

Value: TCH/F4.8 acceptable

TCH/F9.6 acceptable

TCH/F14.4 acceptable

Maximum number of traffic channels, MaxNumTCH (Note 12)

This element is relevant between the MT and the IWF.

Value: 1 TCH

2 TCH

3 TCH

4 TCH

5 TCH

6 TCH

7 TCH (note11)

8 TCH (note11)

NOTE11: not used by currently specified services

Other modem type, OMT (Note 12)

This element is relevant between the IWF and the fixed network in case of 3.1 kHz audio ex-PLMN

Values: – no other modem type specified in this field

– V.34

User initiated modification indication, UIMI (Note 12)

This element is relevant between the MT and the IWF.

Values: – user initiated modification not requested

– user initiated modification upto 1 TCH requested

– user initiated modification upto 2 TCH requested

– user initiated modification upto 3 TCH requested

– user initiated modification upto 4 TCH requested

NOTE 12: These GBS-related parameters are optional.

For a multislot configuration, the following applies to the parameters contained in the BC-IE:

– Half rate channels are not supported. The MS shall code the radio channel requirement as “Full rate support only MS” or “Dual rate support MS, full rate preferred’. In the second case, the network shall assign full rate channel(s) only.

– The ‘fixed network user rate’ and ‘other modem type’ (ref. table B.4a) takes precedence over the ‘user rate’ and ‘modem type’.

– The ACC indicates which channel coding is acceptable and supported by the MS. In case of CE:NT the TCH/F4.8 and TCH/F9.6 acceptable is equivalent to the support of NIRR. If TCH/F4.8 acceptable only or TCH/F9.6 acceptable only or TCH/F14.4 acceptable only is indicated, the assigned channel type which can be chosen by the network is TCH/F4.8 or TCH/F9.6 or TCH/F14.4, respectively.

– The ‘intermediate rate’ parameter is overridden. The intermediate rate used per each TCH/F is derived from the chosen channel type:

channel type

IR per TCH/F

TCH/F4.8

8 kbit/s

TCH/F9.6

16 kbit/s

TCH/F14.4

intermediate rate is to be defined

– The user rate per TCH is derived from the chosen channel type:

channel type

user rate per TCH

TCH/F4.8

4.8 kbit/s

TCH/F9.6

9.6 kbit/s

For CE:T, the padding procedure described in GSM 04.21 can be applied.

Annex B (Normative):
Setting of Bearer Capability, Low Layer Compatibility and High Layer Compatibility Information Element for GSM Bearer Services and GSM TeleServices