9 Information element codings

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

This clause contains the codings of the signalling elements used. The following conventions are assumed for the sequence of transmission of bits and bytes:

– Each bit position is numbered as 1 to 8.

8

7

6

5

4

3

2

1

– The least significant bit is bit 1 and is transmitted first, followed by bits 2, 3, 4 etc.

– In an element, octets are identified by number. Octet 1 is transmitted first, then octet 2 etc.

– When a field extends over more than one octet, the order of bit values progressively decreases as the octet number increases. The least significant bit of the field is represented by the lowest numbered bit of the highest numbered octet of the field.

– For variable length elements, a length indicator is included. This indicates the number of octets following in the element.

– All spare or reserved bits are set to 0.

9.1 Message discriminator

A 1 octet field is used in all messages to discriminate between Transparent and Non-Transparent messages and also between Radio Link Layer Management, Dedicated Channel Management, Common Channel Management, TRX Management and Location Services messages.

8

7

6

5

4

3

2

1

G7

G6

G5

G4

G3

G2

G1

T

The T-bit is set to 1 to indicate that the message is to be/was considered transparent by BTS. All other messages shall have the T-bit set to 0.

The G-bits are used to group the messages as follows:

G7 G6 G5 G4 G3 G2 G1 Message Group

0 0 0 0 0 0 0 reserved

0 0 0 0 0 0 1 Radio Link Layer Management messages

0 0 0 0 1 0 0 Dedicated Channel Management messages

0 0 0 0 1 1 0 Common Channel Management messages

0 0 0 1 0 0 0 TRX Management messages

0 0 1 0 0 0 0 Location Services messages

All other values are reserved for future use.

9.2 MESSAGE TYPE

The Message Type uniquely identifies the function of the message being sent. It is a single octet and coded in the following way:

8

7

6

5

4

3

2

1

EM

Message type

Bit 8 is the extension bit and is reserved for future use. The following message types are used (all other values are reserved):

8 7 6 5 4 3 2 1 Message Reference

0 0 0 0 – – – – Radio Link Layer Management messages:

0 0 0 1 – DATA REQuest 8.3.1

0 0 1 0 – DATA INDication 8.3.2

0 0 1 1 – ERROR INDication 8.3.3

0 1 0 0 – ESTablish REQuest 8.3.4

0 1 0 1 – ESTablish CONFirm 8.3.5

0 1 1 0 – ESTablish INDication 8.3.6

0 1 1 1 – RELease REQuest 8.3.7

1 0 0 0 – RELease CONFirm 8.3.8

1 0 0 1 – RELease INDication 8.3.9

1 0 1 0 – UNIT DATA REQuest 8.3.10

1 0 1 1 – UNIT DATA INDication 8.3.11

0 0 0 1 – – – – Common Channel Management/TRX Management messages:

0 0 0 1 – BCCH INFOrmation 8.5.1

0 0 1 0 – CCCH LOAD INDication 8.5.2

0 0 1 1 – CHANnel ReQuireD 8.5.3

0 1 0 0 – DELETE INDication 8.5.4

0 1 0 1 – PAGING CoMmanD 8.5.5

0 1 1 0 – IMMEDIATE ASSIGN COMMAND 8.5.6

0 1 1 1 – SMS BroadCast REQuest 8.5.7

1 0 0 1 – RF RESource INDication 8.6.1

1 0 1 0 – SACCH FILLing 8.6.2

1 0 1 1 – OVERLOAD 8.6.3

1 1 0 0 – ERROR REPORT 8.6.4

1 1 0 1 – SMS BroadCast CoMmanD 8.5.8

1 1 1 0 – CBCH LOAD INDication 8.5.9

1 1 1 1 – NOTification CoMmanD 8.5.10

0 0 1 – – – – – Dedicated Channel Management messages:

0 0 0 0 1 – CHANnel ACTIVation 8.4.1

0 0 0 1 0 – CHANnel ACTIVation ACKnowledge 8.4.2

0 0 0 1 1 – CHANnel ACTIVation Negative ACK 8.4.3

0 0 1 0 0 – CONNection FAILure 8.4.4

0 0 1 0 1 – DEACTIVATE SACCH 8.4.5

0 0 1 1 0 – ENCRyption CoMmanD 8.4.6

0 0 1 1 1 – HANDOver DETection 8.4.7

0 1 0 0 0 – MEASurement RESult 8.4.8

0 1 0 0 1 – MODE MODIFY REQuest 8.4.9

0 1 0 1 0 – MODE MODIFY ACKnowledge 8.4.10

0 1 0 1 1 – MODE MODIFY Negative ACKnowledge 8.4.11

0 1 1 0 0 – PHYsical CONTEXT REQuest 8.4.12

0 1 1 0 1 – PHYsical CONTEXT CONFirm 8.4.13

0 1 1 1 0 – RF CHANnel RELease 8.4.14

0 1 1 1 1 – MS POWER CONTROL 8.4.15

1 0 0 0 0 – BS POWER CONTROL 8.4.16

1 0 0 0 1 – PREPROCess CONFIGure 8.4.17

1 0 0 1 0 – PREPROCessed MEASurement RESult 8.4.18

1 0 0 1 1 – RF CHANnel RELease ACKnowledge 8.4.19

1 0 1 0 0 – SACCH INFO MODIFY 8.4.20

1 0 1 0 1 – TALKER DETection 8.4.21

1 0 1 1 0 – LISTENER DETection 8.4.22

1 0 1 1 1 – REMOTE CODEC CONFiguration REPort 8.4.23

1 1 0 0 0 – Round Trip Delay REPort 8.4.24

1 1 0 0 1 – PRE-HANDOver NOTIFication 8.4.25

1 1 0 1 0 – MultiRate CODEC MODification REQest 8.4.26

1 1 0 1 1 – MultiRate CODEC MOD ACKnowledge 8.4.27

1 1 1 0 0 – MultiRate CODEC MOD Negative ACKnowledge 8.4.28

1 1 1 0 1 – MultiRate CODEC MOD PERformed 8.4.29

1 1 1 1 0 – TFO REPort 8.4.30

1 1 1 1 1 – TFO MODification REQuest 8.4.31

0 1 – – – – – – Location Services messages:

0 0 0 0 0 1 – Location Information 8.7.1

9.3 Other information elements

The information elements used and the coding of their Element Identifier fields are:

Element

Identifier bits

8 7 6 5 4 3 2 1 Element name Reference

0 0 0 0 0 0 0 1 Channel Number 9.3.1

0 0 0 0 0 0 1 0 Link Identifier 9.3.2

0 0 0 0 0 0 1 1 Activation Type 9.3.3

0 0 0 0 0 1 0 0 BS Power 9.3.4

0 0 0 0 0 1 0 1 Channel Identification 9.3.5

0 0 0 0 0 1 1 0 Channel Mode 9.3.6

0 0 0 0 0 1 1 1 Encryption Information 9.3.7

0 0 0 0 1 0 0 0 Frame Number 9.3.8

0 0 0 0 1 0 0 1 Handover Reference 9.3.9

0 0 0 0 1 0 1 0 L1 Information 9.3.10

0 0 0 0 1 0 1 1 L3 Information 9.3.11

0 0 0 0 1 1 0 0 MS Identity 9.3.12

0 0 0 0 1 1 0 1 MS Power 9.3.13

0 0 0 0 1 1 1 0 Paging Group 9.3.14

0 0 0 0 1 1 1 1 Paging Load 9.3.15

0 0 0 1 0 0 0 0 Physical Context 9.3.16

0 0 0 1 0 0 0 1 Access Delay 9.3.17

0 0 0 1 0 0 1 0 RACH Load 9.3.18

0 0 0 1 0 0 1 1 Request Reference 9.3.19

0 0 0 1 0 1 0 0 Release Mode 9.3.20

0 0 0 1 0 1 0 1 Resource Information 9.3.21

0 0 0 1 0 1 1 0 RLM Cause 9.3.22

0 0 0 1 0 1 1 1 Starting Time 9.3.23

0 0 0 1 1 0 0 0 Timing Advance 9.3.24

0 0 0 1 1 0 0 1 Uplink Measurements 9.3.25

0 0 0 1 1 0 1 0 Cause 9.3.26

0 0 0 1 1 0 1 1 Measurement result number 9.3.27

0 0 0 1 1 1 0 0 Message Identifier 9.3.28

0 0 0 1 1 1 0 1 reserved

0 0 0 1 1 1 1 0 System Info Type 9.3.30

0 0 0 1 1 1 1 1 MS Power Parameters 9.3.31

0 0 1 0 0 0 0 0 BS Power Parameters 9.3.32

0 0 1 0 0 0 0 1 Pre-processing Parameters 9.3.33

0 0 1 0 0 0 1 0 Pre-processed Measurements 9.3.34

0 0 1 0 0 0 1 1 reserved

0 0 1 0 0 1 0 0 SMSCB Information 9.3.36

0 0 1 0 0 1 0 1 MS Timing Offset 9.3.37

0 0 1 0 0 1 1 0 Erroneous Message 9.3.38

0 0 1 0 0 1 1 1 Full BCCH Information 9.3.39

0 0 1 0 1 0 0 0 Channel Needed 9.3.40

0 0 1 0 1 0 0 1 CB Command type 9.3.41

0 0 1 0 1 0 1 0 SMSCB message 9.3.42

0 0 1 0 1 0 1 1 Full Immediate Assign Info 9.3.35

0 0 1 0 1 1 0 0 SACCH Information 9.3.29

0 0 1 0 1 1 0 1 CBCH Load Information 9.3.43

Element

Identifier bits

8 7 6 5 4 3 2 1 Element name Reference

0 0 1 0 1 1 1 0 SMSCB Channel Indicator 9.3.44

0 0 1 0 1 1 1 1 Group call reference 9.3.45

0 0 1 1 0 0 0 0 Channel description 9.3.46

0 0 1 1 0 0 0 1 NCH DRX information 9.3.47

0 0 1 1 0 0 1 0 Command indicator 9.3.48

0 0 1 1 0 0 1 1 eMLPP Priority 9.3.49

0 0 1 1 0 1 0 0 UIC 9.3.50

0 0 1 1 0 1 0 1 Main channel reference 9.3.51

0 0 1 1 0 1 1 0 MultiRate configuration 9.3.52

0 0 1 1 0 1 1 1 MultiRate Control 9.3.53

0 0 1 1 1 0 0 0 Supported Codec Types 9.3.54

0 0 1 1 1 0 0 1 Codec Configuration 9.3.55

0 0 1 1 1 0 1 0 Round Trip Delay 9.3.56

0 0 1 1 1 0 1 1 TFO Status 9.3.57

0 0 1 1 1 1 0 0 LLP APDU 9.3.58

0 0 1 1 1 1 0 1

to

1 1 1 0 1 1 1 1 Reserved for future use

1 1 1 1 0 0 0 0

to

1 1 1 1 1 1 1 1 Not used

9.3.1 Channel Number

In the direction BSC to BTS the Channel Number parameter is used to indicate on which physical channel/subchannel the message is to be sent. In the direction BTS to BSC the Channel Number indicates on which physical channel/subchannel the message was received. It is coded in two octets as follows:

8

7

6

5

4

3

2

1

Element identifier

1

C5

C4

C3

C2

C1

TN

2

The C-bits describe the channel as follows:

C5

C4

C3

C2

C1

0

0

0

0

1

Bm + ACCH’s

0

0

0

1

T

Lm + ACCH’s

0

0

1

T

T

SDCCH/4 + ACCH

0

1

T

T

T

SDCCH/8 + ACCH

1

0

0

0

0

BCCH

1

0

0

0

1

Uplink CCCH (RACH)

1

0

0

1

0

Downlink CCCH (PCH + AGCH)

The T-bits indicate, coded in binary, the sub-channel number as specified in 3GPP TS 05.02.

TN is time slot number, binary represented as in 3GPP TS 05.02.

9.3.2 Link Identifier

This element identifies the signalling channel and SAPI of the radio data link.

8

7

6

5

4

3

2

1

Element identifier

1

C2

C1

NA

priority

SAPI

2

The NA bit (bit 6 in octet 2) is set to 1 to indicate thet the Link Identifier is not applicable for this message. In all other cases it is set to 0.

The C-bits indicate the channel type as follows:

C2 C1

0 0

main signalling channel (FACCH or SDCCH)

0 1

SACCH

All other values are reserved for future use.

The SAPI field contains the SAPI value as defined in 3GPP TS 04.05.

The priority field contains the message priority for SAPI 0, as defined in 3GPP TS 04.06, as follows:

0 0 normal priority

0 1 high priority

1 0 low priority

All other values for SAPI 0 and all values for other SAPIs are reserved for future use.

9.3.3 Activation Type

This element is used to indicate the type of activation requested in the CHANnel ACTIVation message. It is coded in two octets as follows:

8

7

6

5

4

3

2

1

Element identifier

1

R

Reserved

A3

A2

A1

2

The R bit indicates if the procedure is an initial activation or a reactivation.

R

0

Initial activation

1

Reactivation

The A-bits indicate the type of activation, which defines the access procedure and the operation of the data link layer, as follows:

A3 A2 A1

0 0 – Activation related to intra-cell channel change

0 – related to immediate assignment procedure

1 – related to normal assignment procedure

0 1 – Activation related to inter-cell channel change (handover)

0 – related to asynchronous handover procedure

1 – related to synchronous handover procedure

1 0 – Activation related to secondary channels

0 – related to additional assignment procedure

1 – related to multislot configuration

All other values reserved for future use.

NOTE: For the main TCH channel in a Multislot configuration activation types for intra-cell and inter-cell channel change are used.

9.3.4 BS Power

This information element indicates the TRX transmission power level on a particular channel.

8

7

6

5

4

3

2

1

Element identifier

1

Reserved

FPC

Power Level

2

The FPC (Fast Power Control) field (octet 2) indicates whether Fast Measurement Reporting and Power Control mechanism is used. It is coded as follows:

Value

0 Fast Power Control not in use

1 Fast Power Control in use

The Power Level field (octet 2) indicates the number of 2 dB steps by which the power shall be reduced from its nominal value, Pn, set by the network operator to adjust the coverage. Thus the Power Level values correspond to the following powers (relative to Pn):

Value

Power level

0 0 0 0 0

Pn

0 0 0 0 1

Pn – 2 dB

0 0 0 1 0

Pn – 4 dB

.

.

0 1 1 1 0

Pn – 28 dB

0 1 1 1 1

Pn – 30 dB

All other values are reserved for future use.

See also 3GPP TS 05.05, subclause 4.1.2 and 3GPP TS 05.08, subclause 4.5.

9.3.5 Channel Identification

This information element describes some aspects of a channel together with its SACCH.

8

7

6

5

4

3

2

1

Element identifier

1

Length

2

04.08 "Channel Description"

*

04.08 "Mobile Allocation"

*

A * denotes that the whole of the 04.08 element including the element identifier and length should be included. The 04.08 "Mobile Allocation" shall for compatibility reasons be included but empty, i.e. the length shall be zero.

9.3.6 Channel Mode

This element gives information on the mode of coding/decoding and transcoding/rate adaption of a channel.

8

7

6

5

4

3

2

1

Element identifier

1

Length

2

Reserved for future use

DTXd

DTXu

3

Speech or data indicator

4

Channel rate and type

5

Speech coding algor./data rate + transp ind

6

The DTX bits of octet 3 indicate whether DTX is applied:

1 DTX is applied

0 DTX is not applied.

DTXd indicates use of DTX in the downlink direction (BTS to MS) and DTXu indicates use of DTX in the uplink direction (MS to BTS).

The "Speech or data indicator" field (octet 4) is coded as follows:

0000 0001 Speech

0000 0010 Data

0000 0011 Signalling

All other values are reserved.

The "Channel rate and type" field (octet 5) is coded as follows:

0000 0001

SDCCH

0000 1000

Full rate TCH channel Bm

0000 1001

Half rate TCH channel Lm

0000 1010

Full rate TCH channel bi-directional Bm, Multislot configuration

0001 1010

Full rate TCH channel uni-directional downlink Bm, Multislot configuration

0001 1000

Full rate TCH channel Bm Group call channel

0001 1001

Half rate TCH channel Lm Group call channel

0010 1000

Full rate TCH channel Bm Broadcast call channel

0010 1001

Half rate TCH channel Lm Broadcast call channel

All other values are reserved.

The "speech coding algorithm/data rate + transparency indicator" field (octet 6) is coded as follows:

If octet 4 indicates speech, then octet 6 is coded as follows:

0000 0001 GSM speech coding algorithm version 1

0001 0001 GSM speech coding algorithm version 2

0010 0001 GSM speech coding algorithm version 3

All other values are reserved.

If octet 4 indicates signalling then octet 6 is coded as follows:

0000 0000 No resources required

All other values are reserved.

NOTE: GSM speech coding algorithm version 3 is also referred as GSM adaptive multirate speech coding algorithm version 1.

If octet 4 indicates data, then octet 6 is coded as follows:

8

7

6

5

4

3

2

1

ext

T/NT

Rate

octet 6

Bit 8: Reserved for extension

Bit 7: 0 Transparent service

1 Non-transparent service.

For the non-transparent service, bits 6 to 1 indicate the radio interface data rate:

65 4321

10 0001 asymmetric 43.5 kbit/s (downlink) + 14.5 kbit/s (uplink)

10 0010 asymmetric 29.0 kbit/s (downlink) + 14.5 kbit/s (uplink)

10 0011 asymmetric 43.5 kbit/s (downlink) + 29.0 kbit/s (uplink)

10 1001 asymmetric 14.5 kbit/s (downlink) + 43.5 kbit/s (uplink)

10 1010 asymmetric 14.5 kbit/s (downlink) + 29.0 kbit/s (uplink)

10 1011 asymmetric 29.0 kbit/s (downlink) + 43.5 kbit/s (uplink)

11 0100 43.5 kbit/s

11 0001 28.8 kbit/s

01 1000 14.5 kbit/s

01 0000 12 kbit/s

01 0001 6 kbit/s

all other values are reserved.

For the transparent service, bits 6‑1 indicate the data rate:

65 4321

11 1000 32 kbit/s

11 1001 29 kbit/s

01 1000 14.4 kbit/s

01 0000 9.6 kbit/s

01 0001 4.8 kbit/s

01 0010 2.4 kbit/s

01 0011 1.2 kbit/s

01 0100 600 bit/s

01 0101 1 200/75 bit/s (1 200 network-to-MS, 75 MS-to-network)

All other values are reserved.

9.3.7 Encryption information

This element is a variable length element. It contains necessary information to control encryption devices.

8

7

6

5

4

3

2

1

Element identifier

1

Length

2

Algorithm identifier

3

Key

4

n

The Algorithm Identifier field (octet 3) indicates the relevant ciphering algorithm. It is coded as:

0000 0000

Reserved

0000 0001

No encryption shall be used.

0000 0010

GSM encryption algorithm version 1 (A5/1)

0000 0011

GSM A5/2

0000 0100

GSM A5/3

0000 0101

GSM A5/4

0000 0110

GSM A5/5

0000 0111

GSM A5/6

0000 1000

GSM A5/7

All other values are reserved

The Key field (octets 4-n) indicates the ciphering key. It shall be an integral number of octets and the length is given as the value of the Length field minus 1.

9.3.8 Frame Number

This element contains the absolute frame number (FN) modulo 42432. It is used to carry the current timing in BTS to BSC for calculation of the Starting Time parameter required in some messages.

8

7

6

5

4

3

2

1

Element identifier

1

T1′

T3 (high)

2

T3 (low)

T2

3

Octets 2‑3 are coded as defined for octets 2‑3 of the Starting Time information element of 3GPP TS 04.08.

9.3.9 Handover reference

The information is coded in two octets and contains the hand-over reference value.

8

7

6

5

4

3

2

1

Element identifier

1

Hand─over reference

2

The Handover Reference octet contains the handover reference value as defined in 3GPP TS 04.08.

9.3.10 L1 Information

This element carries the information used in the L1 header of SACCH blocks.

8

7

6

5

4

3

2

1

Element identifier

1

MS power level

FPC

Reserved

2

Actual Timing Advance

3

Octets 2‑3 contain the L1 header information of SACCH blocks. The information fields and codings are as defined in 3GPP TS 04.04.

9.3.11 L3 Information (message name)

This element contains a link layer service data unit (L3 message). It is used to forward a complete L3 message as specified in 3GPP TS 04.08 between BTS and BSC.

8

7

6

5

4

3

2

1

Element identifier

1

Length

2

Indicator

3

Link Layer Service Data Unit

4

(i.e. a layer 3 message

as defined in 3GPP TS 04.08)

n

The Length Indicator field (octets 2‑3) indicates in binary the remaining length of the element (octets 4-n). The most significant bit is bit 8 of octet 2 and the least significant bit is bit 1 of octet 3.

Octets 4-n contain the complete L3 message as defined in 3GPP TS 04.08. In the message format section, the 04.08 message name to be included is indicated within brackets.

9.3.12 MS Identity

This element carries the identity of an MS (TMSI or IMSI). It is a variable length element.

8

7

6

5

4

3

2

1

Element identifier

1

Length

2

3

MS Identity

N

The MS Identity field (octets 3-N) is coded as specified for the Mobile Identity information element of 3GPP TS 04.08, octets 3-N.

9.3.13 MS Power

This element carries the power level of MS.

8

7

6

5

4

3

2

1

Element identifier

1

Reserved

FPC

Power Level

2

The FPC (Fast Power Control) field (octet 2) indicates whether Fast Measurement Reporting and Power Control mechanism is used. It is coded as follows:

Value

0 Fast Power Control not in use

1 Fast Power Control in use

The coding and meaning of the Power Level field is as defined in 3GPP TS 05.05 and 3GPP TS 05.08. See also 3GPP TS 04.04.

9.3.14 Paging Group

This element carries the paging population of an MS to be paged.

8

7

6

5

4

3

2

1

Element identifier

1

Paging Group

2

The Paging Group field (octet 2) contains the binary representation of the paging group as defined in 3GPP TS 05.02.

9.3.15 Paging Load

This element carries data about the load of a paging channel (PCH).

8

7

6

5

4

3

2

1

Element identifier

1

2

Paging Buffer Space

3

The Paging Buffer Space field (octets 2‑3) indicates the remaining space for Paging Commands associated with this CCCH timeslot, given as the number of additional Paging Commands that it is possible to store. The number is binary coded with the most significant bit in bit 8 of octet 2 and the least significant bit in bit 1 of octet 3.

9.3.16 Physical Context

This element contains supplementary information on the transmission/reception process. It is a variable length element.

8

7

6

5

4

3

2

1

Element identifier

1

Length

2

Physical

3

Context

Information

N

The Physical Context Information field is not specified. This information should not be analysed by BSC, but merely forwarded from one TRX/channel to another.

9.3.17 Access Delay

This element contains the delay of the access burst as measured by BTS at random access or at handover access.

8

7

6

5

4

3

2

1

Element identifier

1

Access Delay

2

The Access Delay field contains the delay of the access burst as measured by BTS. The delay is expressed as defined for the Timing Advance TA in 3GPP TS 05.10 but with the range extended to 8 bits, i.e. the six least significant bits of the field correspond to the Timing Advance except for GSM 400 where all the 8 bits are used.

9.3.18 RACH Load

This element is used to carry information on the load of the RACH (Random Access Channel) associated with this CCCH timeslot. It is of variable length.

8

7

6

5

4

3

2

1

Element identifier

1

Length

2

3

RACH Slot Count

4

5

RACH Busy Count

6

7

RACH Access Count

8

9

Supplementary

Information

N

The RACH Slot Count field (octets 3‑4) indicates the total number of available access slots over which the measurement (counting) was performed. The value is binary coded with the most significant bit in bit 8 of the first octet and the least significant bit in bit 1 of the second octet.

The RACH Busy Count field (octets 5‑6) indicates the number of RACH burst periods during which the received signal level has exceeded a given threshold. This will give a measure of the number of "busy" random access slots. The value is binary coded with the most significant bit in bit 8 of the first octet and the least significant bit in bit 1 of the second octet.

The RACH Access Count field (octets 7‑8) indicates the number of received access bursts during the same measurement period. The value is binary coded with the most significant bit in bit 8 of the first octet and the least significant bit in bit 1 of the second octet.

The busy count signal level threshold and the measurement period are parameters set by O&M.

The Supplementary Information field may carry additional operator dependent information.

9.3.19 Request Reference

This element carries the Request Reference parameters used for contention resolution on RACH.

8

7

6

5

4

3

2

1

Element identifier

1

RA

2

T1′

T3 (high)

3

T3 (low)

T2

4

Octets 2‑4 are coded as the corresponding fields of the Request Reference element of 3GPP TS 04.08. (Octet 2, RA, is the Random Access Information field set by MS in the CHANnel REQuest message. Octets 3‑4 contain the absolute frame number modulo 42432 for the frame number when the access burst was received, see Starting Time information element of 3GPP TS 04.08).

9.3.20 Release Mode

This element is used to distinguish between normal release and local end release of the radio data link connection.

8

7

6

5

4

3

2

1

Element identifier

1

Reserved for future use

M

2

The M bit is coded as follows:

0 normal release

1 local end release

9.3.21 Resource Information

This element is used to indicate the interference level for each of the idle channels of a TRX.

8

7

6

5

4

3

2

1

Element identifier

1

Length

2

Channel Number (1)

3

Interference level (1)

4

Channel Number (N)

N-1

Interference level (N)

N

The Length field indicates in binary the remaining length of the element (octets 3-N).

Octets 3-N forms a list of Channel Numbers and Interference levels measured on the corresponding channel.

The Channel Number octet is coded as octet 2 of the Channel Number information element, subclause 9.3.1.

The Interference Level octet is coded as follows:

8

7

6

5

4

3

2

1

Interf Band

Reserved for future use

The Interf Band field (bits 6‑8) indicates in binary the interference level expressed as one of five possible interference level bands as defined by O&M. The interference level is averaged over a period of Intave (parameter set by O&M, see 3GPP TS 05.08) immediately before the transmission of the RF RESource INDication message. See also 3GPP TS 08.08, subclause 3.1.3.1 and 3GPP TS 05.08, subclause 3.1 e) of appendix A.

9.3.22 RLM Cause

This element is used to indicate the precise protocol error or the reason for a release on the radio link layer.

8

7

6

5

4

3

2

1

Element identifier

1

Length

2

E

Cause Value

3

The Cause Value is a one octet field if the extension bit is set to 0. If the extension bit is set to 1, the Cause Value is a two octet field.

The Cause Value field is coded as follows:

8 7 6 5 4 3 2 1

0 0 0 0 0 0 0 0

reserved

0 0 0 0 0 0 0 1

timer T200 expired (N200+1) times

0 0 0 0 0 0 1 0

re-establishment request

0 0 0 0 0 0 1 1

unsolicited UA response

0 0 0 0 0 1 0 0

unsolicited DM response

0 0 0 0 0 1 0 1

unsolicated DM response, multiple frame established state

0 0 0 0 0 1 1 0

unsolicited supervisory response

0 0 0 0 0 1 1 1

sequence error

0 0 0 0 1 0 0 0

U-frame with incorrect parameters

0 0 0 0 1 0 0 1

S-frame with incorrect parameters

0 0 0 0 1 0 1 0

I-frame with incorrect use of M bit

0 0 0 0 1 0 1 1

I-frame with incorrect length

0 0 0 0 1 1 0 0

frame not implemented

0 0 0 0 1 1 0 1

SABM command, multiple frame established state

0 0 0 0 1 1 1 0

SABM frame with information not allowed in this state

All other values are reserved for future use.

9.3.23 Starting Time

This element provides the starting time expressed as FN modulo 42432 (FN is absolute frame number).

8

7

6

5

4

3

2

1

Element identifier

1

T1′

T3 (high)

2

T3 (low)

T2

3

Octets 2‑3 are coded as defined for octets 2‑3 of the Starting Time information element of 3GPP TS 04.08.

9.3.24 Timing Advance

This element contains the timing advance to be used by MS in subsequent communications. It is calculated by BTS at the reception of a CHANnel REQuest message (random access burst) or a handover access burst.

8

7

6

5

4

3

2

1

Element identifier

1

Timing Advance

2

The Timing Advance field contains the timing advance TA as specified in 3GPP TS 05.10.

Bits 7‑8 of octet 2 are used in GSM 400 for support of extended cell range. For all other bands bit 7-8 are spare according to 04.18.

9.3.25 Uplink Measurements

This element is used to report the results of the TRX measurements on the uplink radio path of an activated basic radio channel. It is of variable length.

8

7

6

5

4

3

2

1

Element identifier

1

Length

2

rfu

DTXd

RXLEV─FULL─up

3

Reserved

RXLEV─SUB─up

4

Reserved

RXQUAL─FULL─up

RXQUAL─SUB─up

5

Supplementary

6

Measurement

Information

N

rfu = Reserved for Future Use.

The Length field indicates in binary the remaining length of the element (octets 3-N).

Octets 3‑5 contain results from measurements made by TRX on the uplink.

The Supplementary Measurement Information field (octets 6-N) may carry additional operator dependent information.

The DTXd field (octet 3) indicates whether DTX was employed by TRX on the downlink transmission during the measurement period.

The RXLEV-FULL-up and RXLEV-SUB-up fields (octets 3‑4) report the average uplink signal level as measured by TRX over the measurement period on all slots and on a subset of the slots respectively (see 3GPP TS 05.08, subclause 8.2). Each field is coded as defined in 3GPP TS 05.08, subclause 8.1.4.

The RXQUAL-FULL-up and RXQUAL-SUB-up fields (octet 5) report the average uplink quality as measured by TRX over the measurement period on all slots and on a subset of the slots respectively (see 3GPP TS 05.08, subclause 8.2). Each field is coded as defined in 3GPP TS 05.08, subclause 8.2.4.

9.3.26 Cause

The cause element is used to indicate the reason for a particular event to have occurred and is coded as shown below.

8

7

6

5

4

3

2

1

Element identifier

1

Length

2

E

Cause Value

3

Cause Extension

3a

4

Diagnostic(s) if any

N

The Length field indicates in binary the remaining length of the element (octets 3-N).

The Cause Value is a single octet field (octet 3) if the extension bit E (bit 8) is set to 0. If it is set to 1 then the cause value is a 2 octet field (octets 3 and 3a).

The Cause Value is divided into two fields: a class (bits 5‑7 of octet 3) and a value within the class (bits 1‑4 of octet 3).

If the value of the first octet of the cause field is 1XXX 0000 then the second octet is reserved for national applications (XXX will still indicate the class).

Diagnostic information is not available for every cause, see the table below. When available, it is coded in the same way as the corresponding information element in clause 9. Inclusion of diagnostics is optional.

Classes:

Class (000): Normal event

Class (001): Normal event

Class (010): Resource unavailable

Class (011): Service or option not available

Class (100): Service or option not implemented

Class (101): Invalid message (e.g. parameter out of range)

Class (110): Protocol error

Class (111): Interworking

CAUSE VALUES:

Class

Value

Cause

Diagnostics

0 0 0

– – – –

Normal Event

0 0 0

0 0 0 0

radio interface failure

Channel Number

0 0 0

0 0 0 1

radio link failure

Channel Number

0 0 0

0 0 1 0

handover access failure

Channel Number

0 0 0

0 0 1 1

talker access failure

Channel Number

0 0 0

0 1 0 0

reserved for international use

0 0 0

0 1 0 1

reserved for international use

0 0 0

0 1 1 0

reserved for international use

0 0 0

0 1 1 1

O&M intervention

0 0 0

1 0 0 0

reserved for international use

0 0 0

1 : : :

0 0 0

1 1 1 0

0 0 0

1 1 1 1

normal event, unspecified

0 0 1

– – – –

Normal Event

0 0 1

0 0 0 0

reserved for international use

0 0 1

0 : : :

0 0 1

0 1 1 1

0 0 1

1 0 0 0

reserved for national use

0 0 1

1 : : :

0 0 1

1 1 1 1

0 1 0

– – – –

Resource unavailable

0 1 0

0 0 0 0

equipment failure

0 1 0

0 0 0 1

radio resource not available

Channel Number

0 1 0

0 0 1 0

terrestrial channel failure

Channel Number

0 1 0

0 0 1 1

CCCH overload

Channel Number

0 1 0

0 1 0 0

ACCH overload

Channel Number

0 1 0

0 1 0 1

processor overload

0 1 0

0 1 1 0

reserved for international use

0 1 0

0 1 1 1

BTS not equipped

0 1 0

1 0 0 0

remote transcoder failure

Channel Number

0 1 0

1 0 0 1

notification overflow

Channel Number

0 1 0

1 0 1 0

reserved for international use

0 1 0

1 0 1 1

reserved for international use

0 1 0

1 1 0 0

reserved for national use

0 1 0

1 1 0 1

reserved for national use

0 1 0

1 1 1 0

reserved for national use

0 1 0

1 1 1 1

resource not available, unspecified

0 1 1

– – – –

Service or Option Not Available

0 1 1

0 0 0 0

requested transcoding/rate adaption not available

Channel Number

0 1 1

0 0 0 1

reserved for international use

0 1 1

: : : :

0 1 1

1 1 1 0

0 1 1

1 1 1 1

service or option not available, unspecified

1 0 0

– – – –

Service or Option Not Implemented

1 0 0

0 0 0 0

encryption algorithm not implemented

Channel Number

1 0 0

0 0 0 1

reserved for international use

1 0 0

0 : : :

1 0 0

0 1 1 1

1 0 0

1 0 0 0

reserved for national use

1 0 0

1 : : :

1 0 0

1 1 1 0

1 0 0

1 1 1 1

service or option not implemented, unspecified

1 0 1

– – – –

Invalid Message

1 0 1

0 0 0 0

radio channel already activated/allocated

Channel Number

1 0 1

0 0 0 1

reserved for international use

1 0 1

0 : : :

1 0 1

0 1 1 1

1 0 1

1 0 0 0

reserved for national use

1 0 1

1 : : :

1 0 1

1 1 1 0

1 0 1

1 1 1 1

invalid message, unspecified

1 1 0

– – – –

Protocol Error

1 1 0

0 0 0 0

message discriminator error

Message Discrim

1 1 0

0 0 0 1

message type error

Message Type

1 1 0

0 0 1 0

message sequence error

Message Type

1 1 0

0 0 1 1

general information element error

1 1 0

0 1 0 0

mandatory information element error

Element Identif

1 1 0

0 1 0 1

optional information element error

Element Identif

1 1 0

0 1 1 0

information element non-existent

Element Identif

1 1 0

0 1 1 1

information element length error

Element Identif

1 1 0

1 0 0 0

invalid information element contents

Inform. Element

1 1 0

1 0 0 1

reserved for international use

1 1 0

1 0 1 0

reserved for international use

1 1 0

1 0 1 1

reserved for international use

1 1 0

1 1 0 0

reserved for national use

1 1 0

1 1 0 1

reserved for national use

1 1 0

1 1 1 0

reserved for national use

1 1 0

1 1 1 1

protocol error, unspecified

1 1 1

– – – –

Interworking

1 1 1

0 0 0 0

reserved for international use

1 1 1

0 : : :

1 1 1

0 1 1 1

1 1 1

1 0 0 0

reserved for national use

1 1 1

1 : : :

1 1 1

1 1 1 0

1 1 1

1 1 1 1

interworking, unspecified

9.3.27 Measurement result number

This element is used by BTS to number, (on a channel), the measurement result messages sent to BSC. It is set to 0 at activation time of the channel. The numbering is modulo 256.

8

7

6

5

4

3

2

1

Element identifier

1

Measurement result number

2

9.3.28 Message Identifier

This element is used to indicate a message type within a message.

8

7

6

5

4

3

2

1

Element identifier

1

Message Type

2

Octet 2 is coded as the Message Type information element, subclause 9.2.

9.3.29 SACCH Information

This element is used to carry the SACCH filling information (System Information messages, EXTENDED MEASUREMENT ORDER message or MEASUREMENT INFORMATION message) that is to be used on a specific channel. The MEASUREMENT INFORMATION message is periodically sent on SACCH.

8

7

6

5

4

3

2

1

Element identifier

1

Length

2

Number of messages

3

Type of 1st message

4

Length of 1st message

5

1st message

j

Type of n’th message

l

Length of n’th message

l+1

N

n’th message

The Length field (octet 2) indicates in binary the total remaining length of the element (octets 3 – N).

The Number of SI messages field (octet 3) indicates in binary the number of messages contained in the element.

The coding of each of these messages consists of a type field (Type of n’th msg), a length field (Length of n’th message) and a message field (n’th message).

The "Type of n’th msg" field indicates the type of SYSTEM INFORMATION, or an EXTENDED MEASUREMENT ORDER message or a MEASUREMENT INFORMATION message that follows in the "n’th message" field. It is coded as follows:

Value

Message

0 0 0 0 0 1 0 1

SYSTEM INFORMATION 5

0 0 0 0 0 1 1 0

SYSTEM INFORMATION 6

0 0 0 0 1 1 0 1

SYSTEM INFORMATION 5bis

0 0 0 0 1 1 1 0

SYSTEM INFORMATION 5ter

0 1 0 0 0 1 1 1

EXTENDED MEASUREMENT ORDER

0 1 0 0 1 0 0 0

MEASUREMENT INFORMATION

All other values are reserved.

The "Length of n’th SI message" field indicates in binary the length of the "n’th message" field that follows.

The "n’th message" field contains a complete SACCH message as defended in 3GPP TS 04.18.

9.3.30 System Info Type

This element is used to indicate the type of SYSTEM INFORMATION message or an EXTENDED MEASUREMENT ORDER message or a MEASUREMENT INFORMATION message as defined in 3GPP TS 04.18 .

8

7

6

5

4

3

2

1

Element identifier

1

Sys Info Type

2

The Sys Info Field (octet 2) indicates the type of message. It is coded as follows:

Value

Message

0 0 0 0 0 0 0 0

SYSTEM INFORMATION 8

0 0 0 0 0 0 0 1

SYSTEM INFORMATION 1

0 0 0 0 0 0 1 0

SYSTEM INFORMATION 2

0 0 0 0 0 0 1 1

SYSTEM INFORMATION 3

0 0 0 0 0 1 0 0

SYSTEM INFORMATION 4

0 0 0 0 0 1 0 1

SYSTEM INFORMATION 5

0 0 0 0 0 1 1 0

SYSTEM INFORMATION 6

0 0 0 0 0 1 1 1

SYSTEM INFORMATION 7

0 0 0 0 1 0 0 0

SYSTEM INFORMATION 16

0 0 0 0 1 0 0 1

SYSTEM INFORMATION 17

0 0 0 0 1 0 1 0

SYSTEM INFORMATION 2bis

0 0 0 0 1 0 1 1

SYSTEM INFORMATION 2ter

0 0 0 0 1 1 0 1

SYSTEM INFORMATION 5bis

0 0 0 0 1 1 1 0

SYSTEM INFORMATION 5ter

0 0 0 0 1 1 1 1

SYSTEM INFORMATION 10

0 1 0 0 0 1 1 1

EXTENDED MEASUREMENT ORDER

0 1 0 0 1 0 0 0

MEASUREMENT INFORMATION

0 0 1 0 1 0 0 0

SYSTEM INFORMATION 13

0 0 1 0 1 0 0 1

SYSTEM INFORMATION 2quater

0 0 1 0 1 0 1 0

SYSTEM INFORMATION 9

0 0 1 0 1 0 1 1

SYSTEM INFORMATION 18

0 0 1 0 1 1 0 0

SYSTEM INFORMATION 19

0 0 1 0 1 1 0 1

SYSTEM INFORMATION 20

All other values are reserved.

9.3.31 MS Power Parameters

This element carries the parameters required by TRX for MS power control.

8

7

6

5

4

3

2

1

Element identifier

1

Length

2

MS Power Control

3

Parameters

N

The MS Power Control Parameters field contains the parameters and limits required when MS power control is to be performed by BTS. The coding is operator dependant. Examples of possible parameters and algorithms can be found in 3GPP TS 05.08 (RXLEV, RX-QUAL-FULL, RX-QUAL-SUB, DISTANCE (Timing Advance) etc.).

9.3.32 BS Power Parameters

This element carries the parameters required by TRX for control of its own transmission power.

8

7

6

5

4

3

2

1

Element identifier

1

Length

2

BS Power Control

3

Parameters

N

The BS Power Control Parameters field contains the parameters and limits required when TRX transmission power control is to be performed by BTS. The coding is operator dependant. Examples of possible parameters and algorithms can be found in 3GPP TS 05.08 (RXLEV, RX-QUAL-FULL, RX-QUAL-SUB, DISTANCE (Timing Advance) etc.).

9.3.33 Pre-processing Parameters

This element contains the parameters required by BTS for the pre‑processing of radio measurement data.

8

7

6

5

4

3

2

1

Element identifier

1

Length

2

reserved for future use

P

3

Pre-processing

4

Parameters

N

The P bit (bit 1 of octet 3) indicates whether pre-processing is to be used and it is coded as follows:

0 use the basic measurement reporting procedure (report raw data);

1 use the pre-processed measurement reporting procedure.

If pre-processing is to be used, the Pre-processing Parameters field (octets 4-N) contains the parameters required by BTS. The coding of this field is operator dependant.

9.3.34 Pre-processed Measurements

This element is used by BTS to report the results of the pre-processing of radio measurement data.

8

7

6

5

4

3

2

1

Element identifier

1

Length

2

Pre-processed

3

Measurements

N

The Pre-processed Measurements field (octets 3-N) contains the results of the pre-processing in BTS. The coding of this field is operator dependant.

9.3.35 Full Immediate Assign Info

This element is used to convey a full L3 immediate assign message (3 types).

8

7

6

5

4

3

2

1

Element identifier

1

Length Indicator

2

Full Immediate

3

Assign Info

25

The Length Indicator field (octet 2) indicates in binary the remaining length of the element (octets 3‑25).

The Full Immediate Assign Info field (octets 3‑25) contains a complete immediate assign message (IMMEDIATE ASSIGN or IMMEDIATE ASSIGN EXTENDED or IMMEDIATE ASSIGN REJECT) as defined in 3GPP TS 04.08.

9.3.36 SMSCB Information

This element is used to convey a complete frame to be broadcast on the CBCH including the Layer 2 header for the radio path.

8

7

6

5

4

3

2

1

Element identifier

1

SMSCB frame

2

24

9.3.37 MS Timing Offset

The information is coded in two octets and contains the MS Timing Offset as measured by the BTS.

8

7

6

5

4

3

2

1

Element identifier

1

Timing Offset

2

The meaning of the MS Timing Offset is as defined in 3GPP TS 05.10. The value of MS Timing Offset is the binary value of the 8-bit Timing Offset field (octet 2) – 63. The range of MS Timing Offset is therefore ‑63 to 192.

9.3.38 Erroneous Message

This information element is used to carry a complete A-bis interface message which was considered erroneous at reception.

8

7

6

5

4

3

2

1

Element identifier

1

Length

2

Received Message

3

N

The Received Message field contains a complete A-bis interface L3 message as defined in clause 8 of this GTS, including Message Discriminator and Message Type.

9.3.39 Full BCCH Information (message name)

This information element contains a complete L3 message as specified in 3GPP TS 04.08.

8

7

6

5

4

3

2

1

Element identifier

1

Length Indicator

2

Layer 3 message

3

as

4

defined

in 3GPP TS 04.08

25

The Length Indicator field (octet 2) indicates in binary the remaining length of the element (octets 3‑25). The most significant bit is bit 8 of octet 2 and the least significant bit is bit 1 of octet 2.

Octets 3‑25 contain the complete L3 message as defined in 3GPP TS 04.08. In the message format section, the 3GPP TS 04.08 message name to be included is indicated within brackets.

9.3.40 Channel Needed

This information element is used to indicate to the mobile station which channel will be needed for the transaction linked to the paging procedure.

8

7

6

5

4

3

2

1

Element identifier

1

Reserved for future use

Channel

2

The Channel Field (bits 1‑2 of octet 2) indicates the further combination of channel which will be needed. It is coded as follows:

Value

Channel Needed.

0 0

Any Channel.

0 1

SDCCH.

1 0

TCH/F (Full rate).

1 1

TCH/F or TCH/H (Dual rate).

9.3.41 CB Command type

This element is used to indicate the type of broadcast requested.

8

7

6

5

4

3

2

1

Element identifier

1

Command

Default Broadcast

0 Spare

Last Block

2

The Command Field (bits 5 to 8) indicates the command to be performed. It is coded as follows:

Value

Command

0 0 0 0

Normal message Broadcast.

1 0 0 0

Schedule message Broadcast.

1 1 1 0

Default message Broadcast.

1 1 1 1

Null message Broadcast.

All other values are reserved.

When the Command Field is different from the value 1110 (Default message Broadcast), the BTS uses the SMSCB message IE together with the Command Field and the Last Block Field to build the blocks sent on the Radio interface, as defined by 3GPP TS 04.12. In that case bit 4 is ignored.

When the Command Field takes the value 1110 (Default message Broadcast), the BTS uses the SMSCB message IE together with the Default Broadcast Field and the Last Block Field to build the blocks sent on the Radio interface, as defined by 3GPP TS 04.12.

The Default Broadcast Field (bit 4) is coded as follows:

Value

Default message to be broadcast

0

Normal message.

1

Null message.

The BTS uses the Last Block Field to signal to the MS the last block containing useful information as defined by 3GPP TS 04.12. This Field (bits 1 and 2) is coded as follows:

Value

Last Block containing useful information

00

Block 4

01

Block 1

10

Block 2

11

Block 3

9.3.42 SMSCB Message

This element is used to convey the message to be broadcast on the CBCH.

8

7

6

5

4

3

2

1

Element identifier

1

Length

2

SMSCB Message

3

N

9.3.43 CBCH Load Information

This information element is used to indicate to the BSC the load situation of CBCH in the BTS.

8

7

6

5

4

3

2

1

Element identifier

1

CBCH
Load
Type

Spare

Message Slot Count

2

The CBCH Load Type field (bit 8 of octet 2) indicates either an underflow or an overflow situation of the CBCH in the BTS. It is coded as follows:

Value

CBCH Load Type

0

Underflow

1

Overflow

The Message Slot Count field (bits 1‑4 of octet 2) indicates either the amount of SMSCB messages that are needed immediately by BTS or the amount of delay in message slots that is needed immediately by BTS depending on the value of the CBCH Load Type field. It is coded as follows:

CBCH Load Type

Message Slot Count

0

indicates the amount of SMSCB messages (1‑15) that are needed immediately by BTS.

1

indicates the amount of delay in message slots (1‑15) that is needed immediately by BTS.

9.3.44 SMSCB Channel Indicator

This element is used to indicate the CB channel [see 3GPP TS 05.02] to be used for broadcasting the data.

8

7

6

5

4

3

2

1

Element identifier

1

Spare

Channel Ind

2

This element is used to indicate the CB channel to be used for broadcasting the data. The Channel Ind field is coded as follows:

Value

Channel Ind

0 0 0 0

Basic CBCH

0 0 0 1

Extended CBCH (supporting the extended CBCH by the network or MSs is optional)

all other values are reserved.

9.3.45 Group call reference

It is coded as follows:

8

7

6

5

4

3

2

1

Element identifier

1

Length

2

Descriptive group or broadcast call reference

3‑8

The octets 3 to 8 are coded in the same way as the octets 1‑6 in the Descriptive group or broadcast call reference information element as defined in 3GPP TS 04.08.

9.3.46 Channel description

This is a variable length element used to pass a radio interface information element from BSC to BTS.

8

7

6

5

4

3

2

1

Element identifier

1

Length

2

Group Channel Description

3‑n

Octet j (j = 3, 4, …, n) is the unchanged octet j‑2 of a radio interface Group Channel description information element as defined in 3GPP TS 04.08, n‑2 is equal to the length of the radio interface Group channel description information element.

9.3.47 NCH DRX information

This is a variable length element used to pass a radio interface information element from BSC to BTS.

8

7

6

5

4

3

2

1

Element identifier

1

Length

2

NCH DRX information

3

Octet 3 bits 1 and 2 are bits 1 and 2 of the radio interface NLN as defined in 3GPP TS 04.08.

Octet 3 bits 3, 4 and 5 are bits 1, 2 and 3 of the radio interface eMLPP priority as defined in 3GPP TS 04.08.

Octet 3 bit 6 is the NLN status parameter as defined in 3GPP TS 04.08.

Octet 3 bits 7 and 8 are spare and set to zero.

9.3.48 Command indicator

8

7

6

5

4

3

2

1

Element identifier

1

Length

2

E

Command Value

3

Command Extension

3a

The Command Value is a single octet field (octet 3) if the extension bit E (bit 8) is set to 0. If it is set to 1 then the Command value is a 2 octet field (octets 3 and 3a).

COMMAND VALUES:

Value

Command

0 0 0 0 0 0 0

Start

0 0 0 0 0 0 1

Stop

0 0 0 0 0 1 0

reserved for international use

0 : : : : : :

1 0 0 0 0 0 0

1 0 0 0 0 0 1

reserved for national use

1 : : : : : :

1 1 1 1 1 1 1

9.3.49 eMLPP Priority

This Information Element contains the eMLPP priority of the call.

It is coded as follows:

8

7

6

5

4

3

2

1

Element identifier

1

spare

call priority

2

The call priority field (bit 3 to 1 of octet 2) is coded in the same way as the call priority field (bit 3 to 1 of octet 5) in the Descriptive group or broadcast call reference information element as defined in 3GPP TS 04.08.

9.3.50 UIC

It is coded as follows:

8

7

6

5

4

3

2

1

Element identifier

1

Length

2

UIC information

3

Octet 3 bits 1 to 6 contain the radio interface octet 2 bits 3 to 8 of the UIC information element as defined in 3GPP TS 04.08.

Octet 3 bits 7 and 8 are spare and set to zero.

9.3.51 Main channel reference

This element contains the main channel reference of a multislot connection.

It is coded in two octets as follows:

8

7

6

5

4

3

2

1

Element identifier

1

Reserved for future use

TN

2

TN is time slot number, binary represented as in 3GPP TS 05.02.

9.3.52 MultiRate configuration

This element gives the description of the multirate speech codec configuration to be applied.

8

7

6

5

4

3

2

1

Element identifier

1

Length

2

Rest of element coded as in 3GPP TS 04.08 not including 3GPP TS 04.08 element identifier or 3GPP TS 04.08 octet length value

3-n

9.3.53 MultiRate Control

This element indicates whether TFO is enabled or not and whether the BSC authorises the BTS to perform autonomously multi-rate codec changes and whether an handover is to be expected.

It is coded in two octets as follows:

8

7

6

5

4

3

2

1

Element identifier

1

Spare

PRE

RAE

TFO

3

The TFO field (bit 1 of octet 3) indicates if TFO is enabled or not. It is coded as follows:

Value

TFO

0

Tandem Free Operation is enabled

1

Tandem Free Operation is disabled

The RAE field (bits 2-3, octet 3) defines whether the RATSCCH mechanism is enabled or not. It is coded as follows:

Value

RAE

0 0

RATSCCH mechanism is generally enabled, the BTS may change the AMR configuration within the given SCS and MACS constraints and within the given radio and Abis channel.

0 1

RATSCCH mechanism will potentially be enabled for one exchange. The BSC will use a MultiRate CODEC MOD REQ message for that purpose

1 0

reserved

1 1

RATSCCH mechanism is generally disabled

The PRE field (bit 4 of octet 3) indicates if an handover is to be expected soon or not. It is coded as follows:

Value

PRE

0

Handover is not expected, respectively has failed

1

Handover is expected soon

9.3.54 Supported Codec Types

This element indicates the codec types supported by the BSS or remote BSS.

It is coded as follows:

8

7

6

5

4

3

2

1

Element identifier

1

Length

2

Sys-ID

3

ext

Codec List

4-n

Preferred Codec Type

n+1

The Sys-ID field (octet 3) identifies the system that sends or has sent the configuration. It should be set to 0000 0000 for GSM.

The Codec List field (octet 4) lists the codec types that are supported by the BSS and Transcoder, and are therefore potential candidates for TFO establishment. If the Preferred Codec Type is not present (this field is set to “1111.1111”), then the Codec List belongs to the remote BSS, otherwise it is the list of alternative Preferred Codec Types. It is coded as follows:

Bit 1:

Set to 1 if the GSM FR Speech Codec is supported.

Bit 2:

Set to 1 if the GSM HR Speech Codec is supported.

Bit 3:

Set to 1 if the GSM EFR Speech Codec is supported.

Bit 4:

Set to 1 if the GSM FR AMR Speech Codec is supported.

Bit 5:

Set to 1 if the GSM HR AMR Speech Codec is supported

Bit 6-7:

Reserved, set to 0.

Bit 8:

Reserved for extension, set to 0.

If bit 4 of the Codec List field (octet 4) indicates that FR AMR is supported or if bit 5 of the Codec List field (octet 4) indicates that HR AMR is supported, the following two octets (octets 5-6) should be coded as follows:

8

7

6

5

4

3

2

1

Spare

TFO_VER

MACS

5

SCS

6

If both FR AMR and HR AMR are supported, the octets 5-6 shall be sent twice. The first occurrence shall correspond to FR AMR configuration, the second one shall correspond to HR AMR configuration.

The MACS field (bits 1-2 of octet 5, if present) indicates the Maximum number of AMR Codec ModeS the BSS can support in the Active Codec Set. It should be coded as follows:

0 0:

A maximum of four codec modes can be supported in the Active Codec Set

0.1:

A maximum of one codec mode can be supported in the Active Codec Set

1.0:

A maximum of two codec modes can be supported in the Active Codec Set

1.1:

A maximum of three codec modes can be supported in the Active Codec Set

The TFO_VER field (bits 3-4 of octet 5, if present) indicates the TFO_VERSION.

0 0 : Version 0 of TFO

All other values reserved for future used

The SCS field (octet 6 if present) indicates the Set of AMR Codec modes Supported by the BSS. It should be coded as follows:

Bit 8:

Set to 1 if the AMR 12.2 Codec Mode is supported.

Bit 7:

Set to 1 if the AMR 10.2 Codec Mode is supported.

Bit 6:

Set to 1 if the AMR 7.95 Codec Mode is supported.

Bit 5:

Set to 1 if the AMR 7.40 Codec Mode is supported.

Bit 4:

Set to 1 if the AMR 6.70 Codec Mode is supported.

Bit 3:

Set to 1 if the AMR 5.90 Codec Mode is supported.

Bit 2:

Set to 1 if the AMR 5.15 Codec Mode is supported.

Bit 1:

Set to 1 if the AMR 4.75 Codec Mode is supported.

The Preferred Codec Field (bits 1-8, octet n+1) indicates the preferred codec type for TFO establishment. It is coded as follows;

0 0 0 0 . 0 0 0 0:

Full Rate Codec is preferred

0 0 0 0 . 0.0 0 1:

Half Rate Codec is preferred

0 0 0 0 . 0 0 1.0:

Enhanced Full Rate Codec is preferred

0 0 0 0 . 0 0 1.1:

FR Adaptive Multi-Rate Codec is preferred

0 0 0 0 . 0 1 0 0:

HR Adaptive Multi-Rate Codec is preferred

1 1 1 1 . 1 1 1 1:

No preferred codec type

All other values reserved for future used

9.3.55 Codec Configuration

This element indicates the active codec in the BSS or the remote BSS

It is coded as follows:

8

7

6

5

4

3

2

1

Element identifier

1

Length

2

Active Codec Type

3

The Active Codec Type field (bits 1-8, octet 3) indicates the type of codec in use. It is coded as follows:

0 0 0 0 . 0 0 0 0:

Full Rate Codec in use

0 0 0 0 . 0 0 0 1:

Half Rate Codec in use

0 0 0 0 . 0 0 1 0:

Enhanced Full Rate Codec in use

0 0 0 0 . 0 0 1 1:

FR Adaptive Multi Rate Codec in use

0 0 0 0 . 0 1 0 0:

HR Adaptive Multi Rate Codec in use

All other values are reserved for future use

If the Active Codec Type field (octet 3) indicates that AMR (FR or HR) is the active codec type, then the following two octets (octets 4-5) shall provide the configuration in use. They shall be coded as follows:

8

7

6

5

4

3

2

1

Spare

ICM

4

Active Codec Set

5

The ICM field (bits 1-2, octet 4) defines the Initial Codec Mode. It is coded as defined in the 3GPP TS 05.09, section 3.4.1.

The Active Codec Set (octet 5) defines the set of AMR codec modes used in the active set. It is coded as defined for the Set of AMR codec modes in the Multi-Rate configuration IE in the 3GPP TS 04.08, section 10.5.2.21aa.

9.3.56 Round Trip Delay

This element indicates the value of the calculated round trip delay between the BTS and the transcoder, or between the BTS and the remote BTS, if TFO is established.

It is coded in 2 octets as follows:

8

7

6

5

4

3

2

1

Element identifier

1

RTD

Delay IND

2

The RTD field is the binary representation of the value of the round trip delay in 20 ms increments.

The Delay IND field indicates if the delay corresponds to a BTS to transcoder delay or to a BTS to remote BTS delay. It is coded as follows:

Value

Delay IND

0

The RTD field contains the BTS-Transcoder round trip delay

1

The RTD field contains the BTS-Remote BTS round trip delay

9.3.57 TFO Status

This element indicates if TFO is established. It is coded in 2 octets as follows :

8

7

6

5

4

3

2

1

Element identifier

1

Spare

TFO

2

The TFO field shall be coded as follows :

Value

TFO

0

TFO is not established

1

TFO is established

9.3.58 LLP APDU

This is a variable length element that conveys an embedded message or message segment associated with the higher level protocol LLP, as defined in 3GPP TS 04.71. This element can be sent from the BSC to the BTS or to the Standalone Type B LMU, and vice versa.

8

7

6

5

4

3

2

1

Element identifier

1

Length

2

The rest of the information element contains the embedded message that contains a Facility Information Element as defined in 3GPP TS 04.71 excluding the Facility IEI and length of Facility IEI octets defined in 3GPP TS 04.71.

3-n

Annex D (informative):
Change history

SMG#

CR

Rev

Subject

New Vers

S29

A035

Modifications to Channel Mode IE due to EDGE

8.0.2

S30

A036

1

ECSD Asymmetry

8.1.0

S30

A037

1

Modification due to Fast Power Control for ECSD

8.1.0

S30

A043

L3 Info IE length in SACCH INFO MODIFY and FILLING

8.1.0

S30

A045

Introduction of the AMR SMG2 TRAU/SMG11 TFO

8.1.0

S30bis

A046

2

Support of extended timing advance information element in 08.58

8.2.0

S30bis

A049

TFO AMR

8.2.0

S30bis

A051

Access delay info element clarification for GSM400

8.2.0

S31

A050

3

Addition of LCS message

8.3.0

Editorial correction to Change History and graphics update for font compatibility

8.3.1

s31bis

A052

Enhanced measurement reporting capability

8.4.0

GP-01

A054

Correction to Channel Mode IE

8.5.0

FPC in figure on BS Power IE re-introduced

8.5.0

GP-02

A056

2G-3G cell reselection and HO, EGPRS

8.6.0

Many table formats corrected. Headers corrected

8.6.0