8 Message formats and contents

08.583GPPBase Station Controler - Base Transceiver Station (BCS-BTS) Interface Layer 3 SpecificationRelease 1999TS

This clause defines the format and contents of the messages sent over the A-bis interface. Similar coding principles as in recs. 04.08 and 08.08 are used.

For each message, the contained Information Elements are listed. For each Information Element, the following information is given:

– Name of Information Element;

– Reference section for the coding of the Information Element;

– Presence condition for the Information Element;

M Mandatory, must always be present;

receiver: if not present, consider message erroneous;

C Conditional, presence depending on e.g.

a) value of other element;

b) presence of optional element;

receiver: if not present when condition met, consider

message erroneous, else accept message;

O Optional, receiver: present or not, accept message;

– Format of Information Element:

T Type only, fixed length, only Element Identifier;

V Value only, fixed length, no Element Identifier included;

TV Type and Value, fixed length, Element Identifier included;

TLV Type, Length and Value, variable length, Element Identifier and Length Indicator included;

– Total length of Information Element; for variable length, lower and upper limits.

NOTE: Maximum message length is determined by the N201 parameter of 3GPP TS 08.56.

In a message, the message discriminator is transmitted first. The purpose is to distinguish between transparent messages (T-bit set to 1) and non-transparent messages (T-bit set to 0) and also between messages related to Radio Link Layer Management, Dedicated Channel Management, Common Channel Management and TRX Management. The octets are sent in the order shown in the description of the messages and information elements.

8.1 Transparent messages

Transparent messages are used at the A-bis interface to convey layer 3 messages for the radio interface as defined in 3GPP TS 04.08 and for which BTS has to take or has taken no specific action. The T‑ bit of the Message Discriminator is set to 1.

In the uplink direction (messages from MS), all messages received in I‑ frames and all messages received in UI-frames except for the MEASurement REPort message are considered as transparent. They are forwarded to BSC as DATA INDication and UNIT DATA INDication messages respectively.

In the downlink direction (messages to MS) all messages as defined in 3GPP TS 04.08 are transparent except for the following messages, which are replaced by BSC-BTS specific messages over the A‑ bis interface and where BTS will send the corresponding L3 message over the radio interface after the necessary actions have been taken:

Message to MS

Replaced on A-bis interface by

CIPHering MODe CoMmanD

ENCRyption CoMmanD

PAGing REQuest

PAGing CoMmanD

NOTIFication

NOTIFication CoMmanD

SYSTEM INFOrmation

BCCH INFOrmation and SACCH FILLing

EXTENDED MEASUREMENT ORDER

SACCH FILLing

Immediate assign (3 types)

IMMEDIATE ASSIGN COMMAND

Transparent messages are sent by BSC as DATA REQuest or UNIT DATA REQuest messages.

8.2 Non-transparent messages (BSC-BTS specific messages)

These messages are used over the A-bis interface for messages on which BTS has to take some action (BSC to BTS direction) and for messages which are the result from actions taken by BTS (BTS to BSC direction). The T-bit of the Message Discriminator is set to 0.

8.3 Radio link layer management messages

These messages are related to Radio Link Layer Management procedures. They all have the following general format:

INFORMATION ELEMENT

REFERENCE

PRESENCE

FORMAT

LENGTH

Message discriminator

9.1

M

V

1

Message type

9.2

M

V

1

Channel number

9.3.1

M

TV

2

Link Identifier

9.3.2

M

TV

2

(Information elements depending on message type)

The messages concerned are the following:

Message name

Reference section

DATA REQuest

8.3.1

DATA INDication

8.3.2

ERROR INDication

8.3.3

ESTablish REQuest

8.3.4

ESTablish CONFirm

8.3.5

ESTablish INDication

8.3.6

RELease REQuest

8.3.7

RELease CONFirm

8.3.8

RELease INDication

8.3.9

UNIT DATA REQuest

8.3.10

UNIT DATA INDication

8.3.11

8.3.1 DATA REQUEST

This message is sent from BSC to BTS to request the sending of a message in acknowledged mode on a radio link layer connection.

INFORMATION ELEMENT

REFERENCE

PRESENCE

FORMAT

LENGTH

Message discriminator

9.1

M

V

1

Message type

9.2

M

V

1

Channel number

9.3.1

M

TV

2

Link Identifier

9.3.2

M

TV

2

L3 Information

9.3.11

M

TLV

>=3

8.3.2 DATA INDICATION

This message is sent from BTS to BSC to indicate the reception of a message in acknowledged mode on a radio link layer connection.

INFORMATION ELEMENT

REFERENCE

PRESENCE

FORMAT

LENGTH

Message discriminator

9.1

M

V

1

Message type

9.2

M

V

1

Channel number

9.3.1

M

TV

2

Link Identifier

9.3.2

M

TV

2

L3 Information

9.3.11

M

TLV

>=3

8.3.3 ERROR INDICATION

This message is sent from BTS to BSC to indicate an abnormal case for a radio link layer connection.

INFORMATION ELEMENT

REFERENCE

PRESENCE

FORMAT

LENGTH

Message discriminator

9.1

M

V

1

Message type

9.2

M

V

1

Channel number

9.3.1

M

TV

2

Link Identifier

9.3.2

M

TV

2

RLM Cause

9.3.22

M

TLV

2‑4

8.3.4 ESTABLISH REQUEST

This message is sent from BSC to BTS to request the establishment of a multi-frame mode (acknowledged mode) link layer connection on the radio path.

INFORMATION ELEMENT

REFERENCE

PRESENCE

FORMAT

LENGTH

Message discriminator

9.1

M

V

1

Message type

9.2

M

V

1

Channel number

9.3.1

M

TV

2

Link Identifier

9.3.2

M

TV

2

8.3.5 ESTABLISH CONFIRM

This message is sent from BTS to BSC to confirm the establishment of a radio link layer connection in multi-frame (acknowledged) mode.

INFORMATION ELEMENT

REFERENCE

PRESENCE

FORMAT

LENGTH

Message discriminator

9.1

M

V

1

Message type

9.2

M

V

1

Channel number

9.3.1

M

TV

2

Link Identifier

9.3.2

M

TV

2

8.3.6 ESTABLISH INDICATION

This message is sent from BTS to BSC to indicate the establishment of a radio link layer connection in multi-frame mode, initiated by an MS.

INFORMATION ELEMENT

REFERENCE

PRESENCE

FORMAT

LENGTH

Message discriminator

9.1

M

V

1

Message type

9.2

M

V

1

Channel number

9.3.1

M

TV

2

Link Identifier

9.3.2

M

TV

2

L3 Information

9.3.11

O 1)

TLV

3-23

1) The L3 Information field is present only if the SABM frame contained a non-empty information field.

NOTE: The "establish mode" parameter appearing in 3GPP TS 04.06 is used only on the MS side.

8.3.7 RELEASE REQUEST

This message is sent from BSC to BTS to request the release of multi‑ frame mode of a radio link layer connection.

INFORMATION ELEMENT

REFERENCE

PRESENCE

FORMAT

LENGTH

Message discriminator

9.1

M

V

1

Message type

9.2

M

V

1

Channel number

9.3.1

M

TV

2

Link Identifier

9.3.2

M

TV

2

Release Mode

9.3.20

M

TV

2

8.3.8 RELEASE CONFIRM

This message is sent from BTS to BSC to confirm the release of multi‑ frame mode of a radio link layer connection.

INFORMATION ELEMENT

REFERENCE

PRESENCE

FORMAT

LENGTH

Message discriminator

9.1

M

V

1

Message type

9.2

M

V

1

Channel number

9.3.1

M

TV

2

Link Identifier

9.3.2

M

TV

2

8.3.9 RELEASE INDICATION

This message is sent from BTS to BSC to indicate the release of a radio link layer connection (initiated by MS).

INFORMATION ELEMENT

REFERENCE

PRESENCE

FORMAT

LENGTH

Message discriminator

9.1

M

V

1

Message type

9.2

M

V

1

Channel number

9.3.1

M

TV

2

Link Identifier

9.3.2

M

TV

2

8.3.10 UNIT DATA REQUEST

This message is sent from BSC to BTS to request the sending of a message in unacknowledged mode on a radio link layer connection.

INFORMATION ELEMENT

REFERENCE

PRESENCE

FORMAT

LENGTH

Message discriminator

9.1

M

V

1

Message type

9.2

M

V

1

Channel number

9.3.1

M

TV

2

Link Identifier

9.3.2

M

TV

2

L3 Information

9.3.11

M

TLV

3-25

8.3.11 UNIT DATA INDICATION

This message is sent from BTS to BSC to indicate the reception of a message in unacknowledged mode on a radio link layer connection.

INFORMATION ELEMENT

REFERENCE

PRESENCE

FORMAT

LENGTH

Message discriminator

9.1

M

V

1

Message type

9.2

M

V

1

Channel number

9.3.1

M

TV

2

Link Identifier

9.3.2

M

TV

2

L3 Information

9.3.11

M

TLV

3-23

8.4 DEDICATED CHANNEL MANAGEMENT MESSAGES

These messages are related to Dedicated Channel Management procedures. They all have the following general format:

INFORMATION ELEMENT

REFERENCE

PRESENCE

FORMAT

LENGTH

Message discriminator

9.1

M

V

1

Message type

9.2

M

V

1

Channel number

9.3.1

M

TV

2

(Information elements depending on message type)

The messages concerned are the following:

Message name

Reference section

CHANnel ACTIVation

8.4.1

CHANnel ACTIVation ACKnowledge

8.4.2

CHANnel ACTIVation Negative ACK

8.4.3

CONNection FAILure INDication

8.4.4

DEACTIVATE SACCH

8.4.5

ENCRyption CoMmanD

8.4.6

HANDOver DETection

8.4.7

TALKER DETection

8.4.21

LISTENER DETection

8.4.22

MEASurement RESult

8.4.8

MODE MODIFY REQuest

8.4.9

MODE MODIFY ACKnowledge

8.4.10

MODE MODIFY Negative ACKnowledge

8.4.11

PHYsical CONTEXT REQuest

8.4.12

PHYsical CONTEXT CONFirm

8.4.13

RF CHANnel RELease

8.4.14

MS POWER CONTROL

8.4.15

BS POWER CONTROL

8.4.16

PREPROCecc CONFIGure

8.4.17

PREPROCessed MEASurement RESult

8.4.18

RF CHANnel RELease ACKnowledge

8.4.19

SACCH INFO MODIFY

8.4.20

REMOTE CODEC CONFiguration REPort

8.4.23

Round Trip Delay REPort

8.4.24

PRE-HANDOver NOTIFication

8.4.25

MultiRate CODEC MODification REQuest

8.4.26

MultiRate CODEC MOD ACKnowledge

8.4.27

MultiRate CODEC MOD Negative ACK

8.4.28

MultiRate CODEC MOD PERformed

8.4.29

TFO REPort

8.4.30

TFO MODification REQuest

8.4.31

8.4.1 CHANNEL ACTIVATION

This message is sent from BSC to BTS in order to activate a radio channel. The attributes of the channel are defined in the message.

INFORMATION ELEMENT

REFERENCE

PRESENCE

FORMAT

LENGTH

Message discriminator

9.1

M

V

1

Message type

9.2

M

V

1

Channel number

9.3.1

M

TV

2

Activation Type

9.3.3

M

TV

2

Channel Mode

9.3.6

M

TLV

8‑9

Channel Identification

9.3.5

O 7)

TLV

8

Encryption information

9.3.7

O 1)

TLV

>=3

Handover Reference

9.3.9

C 2)

TV

2

BS Power

9.3.4

O 3)

TV

2

MS Power

9.3.13

O 3)

TV

2

Timing Advance

9.3.24

C 3) 4)

TV

2

BS Power Parameters

9.3.32

O 5)

TLV

>=2

MS Power Parameters

9.3.31

O 5)

TLV

>=2

Physical Context

9.3.16

O 6)

TLV

>=2

SACCH Information

9.3.29

O 8)

TLV

>=3

UIC

9.3.50

O 9)

TLV

3

Main channel reference

9.3.51

O 10)

TV

2

MultiRate configuration

9.3.52

O 11)

TLV

>=4

MultiRate Control

9.3.53

O 12)

TV

2

Supported Codec Types

9.3.54

O 12)

TLV

>=5

1) The Encryption Information element is only included if ciphering is to be applied.

2) The Handover Reference element is only included if activation type is handover.

3) If BS Power, MS Power and/or Timing Advance elements are present, they are to be used to set the initial transmission power and the initial L1-header.

4) The Timing Advance element must be included if activation type is intra cell channel change.

5) The BS and MS Power Parameters elements are included to indicate that BS and/or MS power control is to be performed by BTS. The maximum power to be used is indicated in the BS and MS Power elements respectively.

6) Optional element for additional physical channel information.

7) Included if compatibility with phase1 is required.

8) Optional element for setting the SACCH filling information individually for this channel. If this element is present, the SACCH filling information as given by this element shall be used for this channel (replacing any SACCH filling information as given by the SACCH FILLING message(s)) until the channel is released or the information is changed by a SACCH INFO MODIFY message. (If this element is not present, the SACCH filling as given by the SACCH FILLING message(s) shall be used.)

9) The UIC element may be included for voice group calls. It is used in the same way as the BSIC for decoding the random access bursts when decoding uplink access bursts. If not included, the BSIC shall be used for decoding uplink access bursts.

10) Optional element for multislot operation, it may be used in case of power control in the BTS.

  1. Included if the Channel Mode indicates that a multi-rate speech codec is used.

12) Optionally included if the Channel Mode indicates that a multi-rate speech codec is used and TFO control is required or to give to the BTS the possibility to change autonomously the multi-rate codec configuration.

8.4.2 CHANNEL ACTIVATION ACKNOWLEDGE

This message is sent from BSC to BTS to acknowledge that the requested channel activation has been completed correctly.

INFORMATION ELEMENT

REFERENCE

PRESENCE

FORMAT

LENGTH

Message discriminator

9.1

M

V

1

Message type

9.2

M

V

1

Channel number

9.3.1

M

TV

2

Frame number

9.3.8

M

TV

3

The Frame Number element is used by BSC to calculate the Starting Time parameter when required.

8.4.3 CHANNEL ACTIVATION NEGATIVE ACKNOWLEDGE

This message is sent from BTS to BSC to indicate that the channel activation could not be performed as requested.

INFORMATION ELEMENT

REFERENCE

PRESENCE

FORMAT

LENGTH

Message discriminator

9.1

M

V

1

Message type

9.2

M

V

1

Channel number

9.3.1

M

TV

2

Cause

9.3.26

M

TLV

>=3

If the Channel Activation message was received with an erroneous Channel number information element, the Channel Activation Negative Acknowledge message is returned with the Channel Number information element equal to the received (and erroneous) Channel number and the Cause value "Mandatory Information Element Error" with Diagnostics equal to the Channel number element identifier value.

8.4.4 CONNECTION FAILURE INDICATION

This message is sent from BTS to BSC to indicate that an active connection has been broken for some reason.

INFORMATION ELEMENT

REFERENCE

PRESENCE

FORMAT

LENGTH

Message discriminator

9.1

M

V

1

Message type

9.2

M

V

1

Channel number

9.3.1

M

TV

2

Cause

9.3.26

M

TLV

>=3

8.4.5 DEACTIVATE SACCH

This message is sent from BSC to BTS in order to deactivate the SACCH of an active channel.

INFORMATION ELEMENT

REFERENCE

PRESENCE

FORMAT

LENGTH

Message discriminator

9.1

M

V

1

Message type

9.2

M

V

1

Channel number

9.3.1

M

TV

2

8.4.6 ENCRYPTION COMMAND

This message is sent from BSC to BTS to start ciphering mode operation.

INFORMATION ELEMENT

REFERENCE

PRESENCE

FORMAT

LENGTH

Message discriminator

9.1

M

V

1

Message type

9.2

M

V

1

Channel number

9.3.1

M

TV

2

Encryption information

9.3.7

M

TLV

>=3

Link Identifier

9.3.2

M

TV

2

L3 Info (CIPH MOD CMD)

9.3.11

M

TLV

6

The L3 Info element contains the complete Ciphering Mode Command message as defined in 3GPP TS 04.08.

8.4.7 HANDOVER DETECTION

This message is sent from BTS to BSC when BTS correctly receives information from an MS on the handover activated channel.

INFORMATION ELEMENT

REFERENCE

PRESENCE

FORMAT

LENGTH

Message discriminator

9.1

M

V

1

Message type

9.2

M

V

1

Channel number

9.3.1

M

TV

2

Access Delay

9.3.17

O 1)

TV

2

1) The Access Delay element is included if the sending of the handover detection message was triggered by the reception of a handover access burst with the correct handover reference.

8.4.8 MEASUREMENT RESULT

This message from BTS to BSC is used to report to BSC the results of radio channel measurements made by BTS (uplink) and to convey the measurement reports from MS received on SACCH and in the L1 headers.

INFORMATION ELEMENT

REFERENCE

PRESENCE

FORMAT

LENGTH

Message discriminator

9.1

M

V

1

Message type

9.2

M

V

1

Channel number

9.3.1

M

TV

2

Measurement result number

9.3.27

M

TV

2

Uplink Measurements

9.3.25

M

TLV

>=5

BS Power

9.3.4

M

TV

2

L1 Information

9.3.10

O 1)

TV

3

L3 Info (MEAS REP, EXT MEAS REP or ENH MEAS REP)

9.3.11

O 1)

TLV

21

MS Timing Offset

9.3.37

O 2)

TV

2

1) The L1 Information element contains the last received L1-header (MS Power and Timing Advance) from MS and the L3 Information element contains the complete MEASurement REPort message EXTended MEASurement REPort message or ENHanced MEASurement REPort message received from MS. They are included only if received since last (EXTended/ENHanced) MEASurement RESult message.

2) MS Timing Offset can be optionally included to increase the accuracy of possible distance measurements.

8.4.9 MODE MODIFY

This message is sent from BSC to BTS to request a change of channel mode of an active channel.

INFORMATION ELEMENT

REFERENCE

PRESENCE

FORMAT

LENGTH

Message discriminator

9.1

M

V

1

Message type

9.2

M

V

1

Channel number

9.3.1

M

TV

2

Channel Mode

9.3.6

M

TLV

8‑9

Encryption information

9.3.7

O 1)

TLV

>=3

Main channel reference

9.3.45

O 2)

TV

2

MultiRate configuration

9.3.52

O 3)

TLV

>=3

Multirate Control

9.3.53

O 4)

TV

2

Supported Codec Types

9.3.54

O 4)

TLV

>=5

1) The Encryption Information element is only included if ciphering is to be applied.

2) Optional element for multislot operation, it may be used in case of power control in the BTS.

3) Included if the Channel Mode indicates that a multi-rate speech codec is used.

4) Optionally included if the Channel Mode indicates that a multi-rate speech codec is used and TFO control is required or to give to the BTS the possibility to change autonomously the multi-rate codec configuration.

8.4.10 MODE MODIFY ACKNOWLEDGE

This message is sent from BTS to BSC to confirm the change of channel mode of an active channel.

INFORMATION ELEMENT

REFERENCE

PRESENCE

FORMAT

LENGTH

Message discriminator

9.1

M

V

1

Message type

9.2

M

V

1

Channel number

9.3.1

M

TV

2

8.4.11 MODE MODIFY NEGATIVE ACKNOWLEDGE

This message is sent from BTS to BSC to indicate that the channel mode modification could not be performed as requested.

INFORMATION ELEMENT

REFERENCE

PRESENCE

FORMAT

LENGTH

Message discriminator

9.1

M

V

1

Message type

9.2

M

V

1

Channel number

9.3.1

M

TV

2

Cause

9.3.26

M

TLV

>=3

8.4.12 PHYSICAL CONTEXT REQUEST

This message is sent from BSC to BTS to request the "physical context" of an active channel.

INFORMATION ELEMENT

REFERENCE

PRESENCE

FORMAT

LENGTH

Message discriminator

9.1

M

V

1

Message type

9.2

M

V

1

Channel number

9.3.1

M

TV

2

8.4.13 PHYSICAL CONTEXT CONFIRM

This message is sent from BTS to BSC as a response to a PHYsical CONTEXT REQuest message. The message contains the "physical context" information.

INFORMATION ELEMENT

REFERENCE

PRESENCE

FORMAT

LENGTH

Message discriminator

9.1

M

V

1

Message type

9.2

M

V

1

Channel number

9.3.1

M

TV

2

BS Power

9.3.4

M

TV

2

MS Power

9.3.13

M

TV

2

Timing Advance

9.3.24

M

TV

2

Physical Context

9.3.16

O 1)

TLV

>=2

1) Optional element for additional physical channel information.

8.4.14 RF CHANNEL RELEASE

This message is sent from BSC to BTS to inform that a radio channel is no longer needed.

INFORMATION ELEMENT

REFERENCE

PRESENCE

FORMAT

LENGTH

Message discriminator

9.1

M

V

1

Message type

9.2

M

V

1

Channel number

9.3.1

M

TV

2

8.4.15 MS POWER CONTROL

This message is sent from BSC to BTS to change the MS power level or the parameters used by TRX to control the MS power.

INFORMATION ELEMENT

REFERENCE

PRESENCE

FORMAT

LENGTH

Message discriminator

9.1

M

V

1

Message type

9.2

M

V

1

Channel number

9.3.1

M

TV

2

MS Power

9.3.13

M

TV

2

MS Power Parameters

9.3.31

O 1)

TLV

>=2

1) If the MS Power Parameters element is present it indicates that the MS power control is to be performed by TRX. The MS Power element then indicates the maximum MS power to be used.

8.4.16 BS POWER CONTROL

This message is sent from BSC to BTS to change the TRX transmission power level or the parameters used by TRX to control its transmission power.

INFORMATION ELEMENT

REFERENCE

PRESENCE

FORMAT

LENGTH

Message discriminator

9.1

M

V

1

Message type

9.2

M

V

1

Channel number

9.3.1

M

TV

2

BS Power

9.3.4

M

TV

2

BS Power Parameters

9.3.32

O 1)

TLV

>=2

1) If the BS Power Parameters element is present it indicates that the TRX transmission power control is to be performed by TRX. The BS Power element then indicates the maximum transmission power to be used.

8.4.17 PREPROCESS CONFIGURE

This message is sent from BSC to BTS to modify the pre-processing parameters used by BTS.

INFORMATION ELEMENT

REFERENCE

PRESENCE

FORMAT

LENGTH

Message discriminator

9.1

M

V

1

Message type

9.2

M

V

1

Channel number

9.3.1

M

TV

2

Preproc. Parameters

9.3.33

M

TLV

>=3

8.4.18 PREPROCESSED MEASUREMENT RESULT

This message is used by BTS to report the results of radio parameter pre-processing.

INFORMATION ELEMENT

REFERENCE

PRESENCE

FORMAT

LENGTH

Message discriminator

9.1

M

V

1

Message type

9.2

M

V

1

Channel number

9.3.1

M

TV

2

Preproc. Measurements

9.3.34

M

TLV

>=2

8.4.19 RF CHANNEL RELEASE ACKNOWLEDGE

This message is sent from BTS to BSC as an acknowledge to a RF CHANnel RELease message.

INFORMATION ELEMENT

REFERENCE

PRESENCE

FORMAT

LENGTH

Message discriminator

9.1

M

V

1

Message type

9.2

M

V

1

Channel number

9.3.1

M

TV

2

8.4.20 SACCH INFO MODIFY

This message is sent from BSC to BTS to modify the SACCH filling information sent on an individual SACCH channel. This new SACCH filling information shall be sent on the indicated channel until the channel is released or the information is changed by another SACCH INFO MODIFY message.

INFORMATION ELEMENT

REFERENCE

PRESENCE

FORMAT

LENGTH

Message discriminator

9.1

M

V

1

Message type

9.2

M

V

1

Channel number

9.3.1

M

TV

2

System Info Type

9.3.30

M

TV

2

L3 Info

9.3.11

O 1)

TLV

22

Starting Time

9.3.23

O 2)

TV

3

1) If the L3 Info information element is not included, this indicates that transmission of the indicated message shall be stopped, i.e. message shall no longer be sent on this channel.

2) The Starting Time element is optionally used to indicate when transmission of the new information is to start and when transmission is to stop.

The System Info Type element indicates the type of SYSTEM INFORMATION/EXTENDED MEASUREMENT ORDER message which follows in the L3 Info field.

The L3 Information element contains the relevant SYSTEM INFORMATION/EXTENDED MEASUREMENT ORDER message as defined in 3GPP TS 04.08.

8.4.21 TALKER DETECTION

This message is sent from BTS to BSC when BTS correctly receives on a channel activated for VGCS an access from an MS indicating that it requires the uplink of the channel.

INFORMATION ELEMENT

REFERENCE

PRESENCE

FORMAT

LENGTH

Message discriminator

9.1

M

V

1

Message type

9.2

M

V

1

Channel number

9.3.1

M

TV

2

Access Delay

9.3.17

O 1)

TV

2

1) The Access Delay element is included if the sending of the uplink access message was triggered by the reception of an uplink access burst with the correct values.

8.4.22 LISTENER DETECTION

This message is sent from BTS to BSC when BTS correctly receives on a channel activated for VGCS or VBS an access from an MS indicating its presence on the channel.

INFORMATION ELEMENT

REFERENCE

PRESENCE

FORMAT

LENGTH

Message discriminator

9.1

M

V

1

Message type

9.2

M

V

1

Channel number

9.3.1

M

TV

2

Access Delay

9.3.17

O 1)

TV

2

  1. The Access Delay element is included if the sending of the uplink access message was triggered by the reception of an uplink access burst with the correct value.

8.4.23 REMOTE CODEC CONFIGURATION REPORT

This message is sent by the BTS to the BSC to report the codec information received from a remote BTS prior to TFO establishment or in TFO.

INFORMATION ELEMENT

REFERENCE

PRESENCE

FORMAT

LENGTH

Message discriminator

9.1

M

V

1

Message type

9.2

M

V

1

Channel number

9.3.1

M

TV

2

Codec Configuration

9.3.55

M

TLV

>=3

Supported Codec Types

9.3.54

M

TLV

>=5

8.4.24 ROUND TRIP DELAY REPORT

This message is sent by the BSC to the BTS to report the computed round trip transmission delay between the BTS and the transcoder or between the BTS and the remote BTS when TFO is established.

INFORMATION ELEMENT

REFERENCE

PRESENCE

FORMAT

LENGTH

Message discriminator

9.1

M

V

1

Message type

9.2

M

V

1

Channel number

9.3.1

M

TV

2

Round Trip Delay

9.3.56

M

TV

2

8.4.25 PRE-HANDOVER NOTIFICATION

This message is sent by the BSC to the serving BTS to notify the BTS that an handover is going to be performed.
It is also sent by the BSC to the serving BTS if the announced handover has failed.

INFORMATION ELEMENT

REFERENCE

PRESENCE

FORMAT

LENGTH

Message discriminator

9.1

M

V

1

Message type

9.2

M

V

1

Channel number

9.3.1

M

TV

2

MultiRateControl

9.3.53

M

TV

2

Codec Configuration

9.3.55

M

TLV

>=3

8.4.26 MULTIRATE CODEC MODIFICATION REQUEST

This message is sent by the BSC to the BTS to request and authorise the BTS to change the Multi-Rate codec configuration using inband signalling message exchange.

INFORMATION ELEMENT

REFERENCE

PRESENCE

FORMAT

LENGTH

Message discriminator

9.1

M

V

1

Message type

9.2

M

V

1

Channel number

9.3.1

M

TV

2

MultiRate Configuration

9.3.52

O 1)

TLV

>=4

1) Not included if the BTS can solve the codec mismatch for TFO establisment

8.4.27 MULTIRATE CODEC MODIFICATION ACKNOLEWDGE

This message is sent by the BTS to the BSC to acknowledge the performed change of the MultiRate Codec configuration, when it was requested by the BSC with the MultiRate CODEC MODification REQuest message

INFORMATION ELEMENT

REFERENCE

PRESENCE

FORMAT

LENGTH

Message discriminator

9.1

M

V

1

Message type

9.2

M

V

1

Channel number

9.3.1

M

TV

2

MultiRate Configuration

9.3.52

O 1)

TLV

>=4

8.4.28 MULTIRATE CODEC MODIFICATION NEGATIVE ACKNOWLEDGE

This message is sent by the BTS to the BSC to report a failure to change the MultiRate Codec Configuration.

INFORMATION ELEMENT

REFERENCE

PRESENCE

FORMAT

LENGTH

Message discriminator

9.1

M

V

1

Message type

9.2

M

V

1

Channel number

9.3.1

M

TV

2

Cause

9.3.26

M

TLV

>=3

8.4.29 MULTIRATE CODEC MODIFICATION PERFORMED

This message is sent by the BTS to the BSC to inform the BSC of a performed change of the MultiRate Codec Configuration in case the BTS is generally authorised to perform this change and has initiated this on its own.

INFORMATION ELEMENT

REFERENCE

PRESENCE

FORMAT

LENGTH

Message discriminator

9.1

M

V

1

Message type

9.2

M

V

1

Channel number

9.3.1

M

TV

2

MultiRate Configuration

9.3.52

M

TLV

>=4

8.4.30 TFO REPORT

This message is sent by the BTS to the BSC to inform the BSC that Tandem Free Operation with AMR is established, or is not established anymore.

INFORMATION ELEMENT

REFERENCE

PRESENCE

FORMAT

LENGTH

Message discriminator

9.1

M

V

1

Message type

9.2

M

V

1

Channel number

9.3.1

M

TV

2

TFO Status

9.3.57

M

TV

1

8.4.31 TFO MODIFICATION REQUEST

This message is sent by the BSC to the BTS to change the configuration of TFO while operating with AMR.

INFORMATION ELEMENT

REFERENCE

PRESENCE

FORMAT

LENGTH

Message discriminator

9.1

M

V

1

Message type

9.2

M

V

1

Channel number

9.3.1

M

TV

2

MultiRateControl

9.3.53

M

TV

2

Supported Codec Type

9.3.54

O 1)

TLV

>=5

1) Optionally included if TFO is enabled within I.E. MultiRateControl

8.5 COMMON CHANNEL MANAGEMENT MESSAGES

These messages are related to Common Channel Management procedures. They all have the following general format:

INFORMATION ELEMENT

REFERENCE

PRESENCE

FORMAT

LENGTH

Message discriminator

9.1

M

V

1

Message type

9.2

M

V

1

Channel number

9.3.1

M

TV

2

(Information elements depending on message type)

The messages concerned are the following:

Message name

Reference section

BCCH INFOrmation

8.5.1

CCCH LOAD INDication

8.5.2

CHANnel ReQuireD

8.5.3

DELETE INDication

8.5.4

PAGING CoMmanD

8.5.5

NOTification CoMmanD

8.5.10

IMMEDIATE ASSIGN COMMAND

8.5.6

SMS BroadCast REQuest

8.5.7

SMS Broadcast Command

8.5.8

CBCH LOAD INDICATION

8.5.9

8.5.1 BCCH INFORMATION

This message is sent from BSC to BTS to indicate new information to be broadcast on BCCH.

INFORMATION ELEMENT

REFERENCE

PRESENCE

FORMAT

LENGTH

Message discriminator

9.1

M

V

1

Message type

9.2

M

V

1

Channel number

9.3.1

M

TV

2

System Info Type

9.3.30

M

TV

2

Full BCCH Info (SYS INFO)

9.3.39

O 1)

TLV

25

Starting Time

9.3.23

O 2)

TV

3

1) If the Full BCCH information element is not included this indicates that transmission of the indicated SYSTEM INFORMATION message shall be stopped.

2) The Starting Time element is optionally used to indicate when transmission of the new information is to start or when transmission is to stop.

The System Info Type element indicates the type of SYSTEM INFORMATION message which follows in the Full BCCH Information element.

The Full BCCH Information element contains the relevant SYSTEM INFORMATION message as defined in 3GPP TS 04.08.

8.5.2 CCCH LOAD INDICATION

This message is sent from BTS to BSC to report the current load on the indicated CCCH timeslot (random access, RACH, and paging, PCH).

INFORMATION ELEMENT

REFERENCE

PRESENCE

FORMAT

LENGTH

Message discriminator

9.1

M

V

1

Message type

9.2

M

V

1

Channel number (note)

9.3.1

M

TV

2

RACH Load

9.3.18

C 1)

TLV

>=8

Paging Load

9.3.15

C 2)

TV

3

NOTE: The BTS may set the "Channel Number" information element in this message to either the "uplink CCCH" or the "downlink CCCH" on that timeslot number.

1) The RACH load information element is included only if the Channel number information indicates "uplink CCCH".

2) The Paging load information element is included only if the Channel number information indicates "downlink CCCH".

8.5.3 CHANNEL REQUIRED

This message is sent from BTS to BSC to indicate the reception of a CHANnel REQuest message (special access burst message) from an MS.

INFORMATION ELEMENT

REFERENCE

PRESENCE

FORMAT

LENGTH

Message discriminator

9.1

M

V

1

Message type

9.2

M

V

1

Channel number

9.3.1

M

TV

2

Request Reference

9.3.19

M

TV

4

Access Delay

9.3.17

M

TV

2

Physical Context

9.3.16

O 1)

TLV

>=2

1) Optional element for additional physical channel information.

The Request Reference element contains the random access reference value sent by MS in the CHANnel REQuest message and some low order bits of the absolute frame number for the reception of the access burst.

8.5.4 DELETE INDICATION

This message is sent from BTS to BSC to indicate the deletion of an access grant message (IMMediate ASSIGN) due to overload of downlink CCCH.

INFORMATION ELEMENT

REFERENCE

PRESENCE

FORMAT

LENGTH

Message discriminator

9.1

M

V

1

Message type

9.2

M

V

1

Channel number

9.3.1

M

TV

2

Full Imm. Assign Info

9.3.35

M

TLV

25

8.5.5 PAGING COMMAND

This message is sent from BSC to BTS to request the paging of an MS.

INFORMATION ELEMENT

REFERENCE

PRESENCE

FORMAT

LENGTH

Message discriminator

9.1

M

V

1

Message type

9.2

M

V

1

Channel number

9.3.1

M

TV

2

Paging Group

9.3.14

M

TV

2

MS Identity

9.3.12

M

TLV

2‑10

Channel Needed

9.3.40

O 1)

TV

2

eMLPP Priority

9.3.49

O 2)

TV

3

1) If the Channel Needed element is not present, the default value is assumed to be 00 (any channel).

2) If the eMLPP Priority is not present then the BTS does not include the eMLPP priority in the radio interface message.

The Paging Group element is used by BTS to calculate the correct DRX paging block to be used for the transmission of the PAGing REQuest message as defined in 3GPP TS 05.02.

8.5.6 IMMEDIATE ASSIGN COMMAND

This message is sent from BSC to BTS to request the transmission of an immediate assignment message.

INFORMATION ELEMENT

REFERENCE

PRESENCE

FORMAT

LENGTH

Message discriminator

9.1

M

V

1

Message type

9.2

M

V

1

Channel number

9.3.1

M

TV

2

Full Imm. Assign Info

9.3.35

M

TLV

25

The Full Imm. Assign Info element contains the relevant immediate assignment message as defined in 3GPP TS 04.08 (IMMEDIATE ASSIGNMENT or IMMEDIATE ASSIGNMENT EXTENDED or IMMEDIATE ASSIGNMENT REJECT) with the "Page Mode" element set to the value "no change".

8.5.7 SMS BROADCAST REQUEST

This message is sent from BSC to BTS to request the sending of a Short Message Service Cell Broadcast message.

INFORMATION ELEMENT

REFERENCE

PRESENCE

FORMAT

LENGTH

Message discriminator

9.1

M

V

1

Message type

9.2

M

V

1

Channel number

9.3.1

M

TV

2

SMSCB Information

9.3.36

M

TV

24

SMSCB Channel Indicator

9.3.44

O 1)

TV

2

The SMSCB Information element contains the complete information to be broadcast on the CBCH as defined in 3GPP TS 04.12 (including the Layer 2 header to be used on the radio path).

1) The SMSCB Channel Indicator IE indicates the CBCH which shall be used for broadcasting the data. If this information element is not present the basic CBCH (see 3GPP TS 05.02) shall be used.

8.5.8 SMS BROADCAST COMMAND

This message is sent from BSC to BTS to command Short Message Service Cell Broadcast.

INFORMATION ELEMENT

REFERENCE

PRESENCE

FORMAT

LENGTH

Message discriminator

9.1

M

V

1

Message type

9.2

M

V

1

Channel number

9.3.1

M

TV

2

CB Command type

9.3.41

M

TV

2

SMSCB message

9.3.42

M

TLV

2‑90

SMSCB Channel Indicator

9.3.44

O 1)

TV

2

The CB Command type IE contains the command to be performed, allowing the BSC to:

– request immediate broadcast i.e. transmission in the next CBCH opportunity;

– set the BTS broadcast default mode.

The SMSCB message IE contains the actual message to be broadcast on the CBCH i.e. a maximum of 88 octets of data. The BTS is responsible for performing the segmentation, building the block types and padding if necessary, see 3GPP TS 04.12 for the message format on the radio path.

1) The SMSCB Channel Indicator IE indicates the CBCH which shall be used for broadcasting the data.
If this information element is not present the basic CBCH [see 3GPP TS 05.02] shall be used.

8.5.9 CBCH LOAD INDICATION

This message is sent from BTS to BSC to indicate a CBCH underflow/overflow situation in the BTS and to request the BSC to accelerate or pause the cell broadcast for a period indicated by BTS.

INFORMATION ELEMENT

REFERENCE

PRESENCE

FORMAT

LENGTH

Message discriminator

9.1

M

V

1

Message type

9.2

M

V

1

Channel number

9.3.1

M

TV

2

CBCH Load Information

9.3.43

M

TV

2

SMSCB Channel Indicator

9.3.44

O 1)

TV

2

The CBCH Load Information element indicates the load situation in CBCH (underflow/overflow) and information about the requested acceleration/suspension period of cell broadcast.

1) The SMSCB Channel Indicator IE indicates the CBCH which shall be used for broadcasting the data. If this information element is not present the basic CBCH [see 3GPP TS 05.02] shall be used.

8.5.10 NOTIFICATION COMMAND

This message is sent from BSC to BTS to request a change of notification for voice group call.

INFORMATION ELEMENT

REFERENCE

PRESENCE

FORMAT

LENGTH

Message discriminator

9.1

M

V

1

Message type

9.2

M

V

1

Channel number

9.3.1

M

TV

2

Command indicator

9.3.48

M 1)

TLV

3‑4

Group call reference

9.3.45

O

TLV

3‑10

Channel Description

9.3.46

O

TLV

3-n

NCH DRX information

9.3.47

O

TLV

3

1) This information element indicates the type of command that is to be performed by the BTS with respect to information contained in the rest of the message.

8.6 TRX MANAGEMENT MESSAGES

These messages are related to TRX Management procedures. They all have the following general format (no channel number included):

INFORMATION ELEMENT

REFERENCE

PRESENCE

FORMAT

LENGTH

Message discriminator

9.1

M

V

1

Message type

9.2

M

V

1

(Information elements depending on message type)

The messages concerned are the following:

Message name Reference section

RF RESource INDication 8.6.1

SACCH FILLing 8.6.2

OVERLOAD 8.6.3

ERROR REPORT 8.6.4

8.6.1 RF RESOURCE INDICATION

This message is sent from BTS to BSC to indicate the interference level on idle channels of a TRX.

INFORMATION ELEMENT

REFERENCE

PRESENCE

FORMAT

LENGTH

Message discriminator

9.1

M

V

1

Message type

9.2

M

V

1

Resource Information

9.3.21

M

TLV

>=2

8.6.2 SACCH FILLING

This message is sent from BSC to BTS to indicate the new broadcast information to be used as filling information on downlink SACCH.

INFORMATION ELEMENT

REFERENCE

PRESENCE

FORMAT

LENGTH

Message discriminator

9.1

M

V

1

Message type

9.2

M

V

1

System Info Type

9.3.30

M

TV

2

L3 Info (SYS INFO)

9.3.11

O 1)

TLV

22

Starting Time

9.3.23

O 2)

TV

3

1) If the L3 Info information element is not included this indicates that transmission of the indicated SYSTEM INFORMATION message shall be stopped.

2) The Starting Time element is optionally used to indicate when transmission of the new information is to start and when transmission is to stop.

The System Info Type element indicates the type of SYSTEM INFORMATION message which follows in the L3 Info field.

The L3 Information element contains the relevant SYSTEM INFORMATION message as defined in 3GPP TS 04.08.

8.6.3 OVERLOAD

This message is sent from BTS to BSC to indicate an overload situation. Possible cause values include:

– CCCH overload;

– ACCH overload;

– processor overload.

INFORMATION ELEMENT

REFERENCE

PRESENCE

FORMAT

LENGTH

Message discriminator

9.1

M

V

1

Message type

9.2

M

V

1

Cause

9.3.26

M

TLV

>=3

8.6.4 ERROR REPORT

This message is sent from BTS to BSC to report a detected error which cannot be reported in any other message.

INFORMATION ELEMENT

REFERENCE

PRESENCE

FORMAT

LENGTH

Message discriminator

9.1

M

V

1

Message type

9.2

M

V

1

Cause

9.3.26

M

TLV

>=3

Message Identifier

9.3.28

O 1)

TV

2

Channel Number

9.3.1

O 2)

TV

2

Link identifier

9.3.2

O 3)

TV

2

Erroneous Message

9.3.38

O 4)

TLV

>=3

1) Used to indicate which type of message was considered erroneous.

2) Used to indicate for which radio channel the error is reported.

3) Used to indicate for which radio L2 link the error is reported.

4) This element may be used to carry the complete erroneous message as it was received from the BSC.

8.7 LOCATION SERVICES MESSAGES

These messages are related to Location Services (LCS).

8.7.1 LOCATION INFORMATION

This message is sent by the BSC, the BTS or Sandalone Type B LMU via Abis interface to convey an embedded LCS LLP message.

INFORMATION ELEMENT

REFERENCE

PRESENCE

FORMAT

LENGTH

Message discriminator

9.1

M

V

1

Message type

9.2

M

V

1

LLP APDU

9.3.58

M

LV

2-N