3.2.3 Signalling Field Element Coding

08.083GPPMobile-services Switching Centre - Base Station system (MSC-BSS) Interface Layer 3 SpecificationRelease 1999TS

The coding rules for signalling field elements are the same as the signalling element coding rules which are defined in sub-clause 3.2.2.

Signalling field elements shall always include a Field Length indicator. A Field Length indicator with a value of zero shall not be considered as an error.

Field Element Identifier Coding

Field Element name

Reference

0000 0001

Extra information

3.2.3.1

0000 0010

Current Channel Type 2

3.2.2.2

0000 0011

Target cell radio information

3.2.3.3

0000 0100

GPRS Suspend information

3.2.3.4

0000 0101

MultiRate configuration information

3.2.3.5

0000 0110

Dual Transfer Mode information

3.2.3.6

0000 0111

Inter RAT Handover Info

3.2.3.7

0000 1000

cdma2000 Capability Information

3.2.3.8

All other values are for future use.

3.2.3.1 Extra information

This field element provides a general flag mechanism that allows the old BSS to indicate to the new BSS flag information.

It is coded as follows:

8

7

6

5

4

3

2

1

Field Element identifier

octet 1

Length

octet 2

octet 3

Octet 2 is a binary indication of the length of the rest of the field element.

Octet 3 is coded as follows:

8

7

6

5

4

3

2

1

spare

lcs

prec

octet 3

Bit 8 to 2 are flags that indicate no information.

prec = Pre-emption Recommendation

0 The old BSS recommends that this allocation request should not cause a pre-emption an existing connection.

1 The old BSS recommends that this allocation request is allowed to preempt an existing connection based on the information supplied in the Priority information element, if available.

In the case the "prec" bit is not present or the Extra Information field element is not present then the new BSS should run pre-emption as specified by the Priority information element, if available.

In the case where the Priority information element is not present in the request then the "prec" element, if present, shall be ignored.

lcs = Location Services (LCS) information

0 No ongoing LCS procedure.

1 An ongoing LCS procedure was interrupted by handover. The new BSS may notify the SMLC when the handover is completed.

3.2.3.2 Current Channel type 2

This Field Element contains a description of the channel allocated to the MS.

It is coded as follows:

8

7

6

5

4

3

2

1

Element identifier

octet 1

Length

octet 2

Channel mode

octet 3

Channel field

octet 4

The channel mode field is coded as follows:

Bit

4321

0000 signalling only

0001 speech (full rate or half rate)

0110 data, 14.5 kbit/s radio interface rate

0011 data, 12.0 kbit/s radio interface rate

0100 data, 6.0 kbit/s radio interface rate

0101 data, 3.6 kbit/s radio interface rate

1111 is reserved

All other values indicate that no information is provided.

Bits 8 to 5 are spare.

The channel field is coded as follows:

Bit

4321

0001 SDCCH

1000 1 Full rate TCH

1001 1 Half rate TCH

1010 2 Full Rate TCHs

1011 3 Full Rate TCHs

1100 4 Full Rate TCHs

1101 5 Full Rate TCHs

1110 6 Full Rate TCHs

1111 7 Full Rate TCHs

0100 8 Full Rate TCHs

0000 is reserved

All other values indicate that no information is provided.

Bits 8 to 5 are spare.

3.2.3.3 Target cell radio information

It is coded as follows:

8

7

6

5

4

3

2

1

Element identifier

octet 1

Length

octet 2

octet 3

Octet 2 is a binary indication of the length of the rest of the element.

Octet 3 is coded as follows:

8

7

6

5

4

3

2

1

RXLEV-NCELL

octet 3

Bit 8 to 7 is spare, set to 0

Bit 6 to 1 is the RXLEV-NCELL field.

The RXLEV-NCELL field is coded as the binary representation of a value N. N corresponds according to the mapping defined in TS. 3GPP TS 05.08 to the received signal strength on the target cell.

3.2.3.4 GPRS Suspend Information

This Field Element contains the contents of the Gb interface SUSPEND ACK PDU.

It is coded as follows:

8

7

6

5

4

3

2

1

Element identifier

octet 1

Length

octet 2

Gb interface TLLI IEI

octet 3

Length of TLLI

octet 4

TLLI

oct 5 – 5+m

Gb interface RAI IEI

octet 6+m

Length of RAI

octet 7+m

RAI

oct 7+m – n

Gb interface SRN IEI

octet n+1

Length of SRN

octet n+2

Suspend reference number

oct n+3 -p

The coding of the fields are not relevant to 3GPP TS 08.08

3.2.3.5 MultiRate configuration Information

This Field Element contains a description of the multi-rate speech codec configuration currently used.

It is coded as follows:

8

7

6

5

4

3

2

1

Element identifier

octet 1

Length

octet 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

octet 3-n

3.2.3.6 Dual Transfer Mode information

This Field Element contains information about a mobile in dual transfer mode. This information may be used for the target BSS to allocate the resources for the RR connection (e.g. TCH/H, TCH in an EGPRS transceiver).

It is coded as follows:

8

7

6

5

4

3

2

1

Element identifier

octet 1

Length

octet 2

Spare

EGPRS ind

STO

ind

DTM

ind

Octet 3

Octet 3

Bit 1 is the dual transfer mode indicator. It indicates whether the MS is in dedicated mode or in dual transfer mode. It is coded as follows:

Bit 1
0 The MS is in dedicated mode in the old cell
1 The MS is in dual transfer mode in the old cell

Bit 2 is the single timeslot operation indicator. It indicates whether the MS has a TCH/H and a PDCH/H; see 3GPP TS 05.02. It is coded as follows:

Bit 2
0 The MS is in multislot operation in the old cell
1 The MS is in single timeslot operation in the old cell

Bit 3 is the EGPRS indicator. It is coded as follows:

Bit 3
0 The MS has no TBF using E-GPRS in the old cell
1 The MS has a TBF using E-GPRS in the old cell

3.2.3.7 Inter RAT Handover Info

The Inter RAT Handover Info information element is coded as follows:

8

7

6

5

4

3

2

1

Field Element identifier

octet 1

Length

octet 2

Inter RAT Handover Info

octet 3-n

Octets 3-n are encoded as Inter RAT Handover Info as defined in TS 3GPP TS 25.331.

3.2.3.8 cdma2000 Capability Information

The cdma2000 Capability Information element is coded as follows:

8

7

6

5

4

3

2

1

Field Element identifier

octet 1

Length

octet 2

cdma2000 capability information

octet 3-n

Octets 3-n are encoded as octets 3-n of the cdma2000 Classmark Change message defined in TS 3GPP TS 04.18.