10 General message format and information elements coding

04.563GPPGSM Cordless Telephony System (CTS), (Phase 1) CTS Radio Interface Layer 3 SpecificationTS

The figures and text in this section describe the Information Elements contents.

10.1 Overview

See corresponding section in GSM 04.08.

10.2 Protocol Discriminator

The Protocol Discriminator (PD) and its use are defined in GSM 04.07 [20].

10.3 Sub-Protocol Discriminator and transaction identifier

10.3.1 Sub-Protocol Discriminator

Bits 5 to 8 of the first octet of every CTS Radio Resource management and CTS Mobility Management message contains the Sub-Protocol Discriminator. The Sub-Protocol Discriminator (SPD) and its use are defined in GSM 04.07.

10.3.2 Transaction identifier

See GSM 04.08.

10.4 Message Type

The message type IE and its use are defined in GSM 04.07 [20]. Tables 10.1/GSM 04.56, and 10.1/GSM 04.08 define the value part of the message type IE used in the Radio Resource management protocol, the Mobility Management protocol, the Call Control protocol, and Session management protocol.

Table 10.1/GSM 04.56: Message types for Radio Resource management

+——————————————————-+

 8 7 6 5 4 3 2 1 

 

 0 0 1 1 1 – – – Channel establishment messages: 

 1 1 1 – CTS IMMEDIATE ASSIGNMENT 

 0 0 1 – CTS IMMEDIATE ASSIGNMENT EXTENDED 

 0 1 0 – CTS IMMEDIATE ASSIGNMENT REJECT 

 

 0 0 1 1 0 – – – Ciphering messages: 

 1 0 1 – CTS CIPHERING MODE COMMAND 

 0 1 0 – CTS CIPHERING MODE COMPLETE 

 

 0 0 1 0 1 – – – Handover messages: 

 0 1 1 – CTS INTRACELL HANDOVER COMMAND 

 1 0 0 – CTS INTRACELLHANDOVER COMPLETE 

 0 0 0 – CTS INTRACELLHANDOVER FAILURE 

 

 0 0 0 0 1 – – – Channel release messages: 

 1 0 1 – CTS CHANNEL RELEASE 

 

 0 0 1 0 0 – – – Paging messages: 

 0 0 1 – CTS PAGING REQUEST 

 0 1 0 – CTS GROUP ALERTING 

 1 0 0 – CTS HUNTING 

 1 1 1 – CTS PAGING RESPONSE 

 

 0 0 0 1 1 – – – System information messages: 

 0 0 1 – CTS SYSTEM INFORMATION TYPE 1 

 0 1 0 – CTS SYSTEM INFORMATION TYPE 2 

 0 1 1 – CTS SYSTEM INFORMATION TYPE 3 

 

 

 0 0 0 1 0 – – – Miscellaneous messages: 

 0 0 0 – CTS CHANNEL MODE MODIFY 

 0 1 0 – CTS RR STATUS 

 1 1 1 – CTS CHANNEL MODE MODIFY ACKNOWLEDGE

 1 0 0 – CTS FREQUENCY REDEFINITION 

 1 0 1 – CTS MEASUREMENT REPORT 

 1 1 0 – CTS CLASSMARK CHANGE 

 0 1 1 – CTS CLASSMARK ENQUIRY 

 

+——————————————————-+

Bit 8 is reserved for possible future use as an extension bit, see GSM 04.07.

Table 10.2/GSM 04.56: Message types for Mobility Management

+——————————————————-+

 8 7 6 5 4 3 2 1 

 

 0 x 0 0 – – – – Registration messages: 

 0 0 0 1 – CTS DETACH INDICATION 

 0 0 1 0 – CTS ATTACH ACCEPT 

 0 1 0 0 – CTS ATTACH REJECT 

 1 0 0 0 – CTS ATTACH REQUEST 

 1 1 0 1 – CTS RE-ATTACH REQUEST 

 1 1 1 0 – CTS RE-ATTACH ACCEPT 

 

 0 x 0 1 – – – – Security messages: 

 0 0 0 1 – CTS MS AUTHENTICATION REJECT 

 0 0 1 0 – CTS MS AUTHENTICATION REQUEST 

 0 1 0 0 – CTS MS AUTHENTICATION RESPONSE 

 0 1 0 1 – CTS FP AUTHENTICATION RESPONSE 

 1 0 1 0 – CTSMSI UPDATE COMMAND 

 1 0 1 1 – CTSMSI UPDATE COMPLETE 

 

 0 x 1 0 – – – – Enrolment messages: 

 0 0 0 1 – CTS ENROLMENT REQUEST 

 0 0 1 0 – CTS ENROLMENT RESPONSE 

 0 0 1 1 – CTS ENROLMENT REJECT 

 0 1 0 0 – CTS DE-ENROLMENT INDICATION 

+——————————————————-+

Bit 8 is reserved for possible future use as an extension bit, see GSM 04.07.

Bit 7 is reserved for the send sequence number in messages sent from the mobile station. In messages sent from the network, bit 7 is coded with a "0". See GSM 04.07.

10.5 Other information elements

See corresponding section in GSM 04.08.

10.5.1 Common information elements.

10.5.1.1 Mobile Identity

The purpose of the Mobile Identity information element is to provide either the international mobile subscriber identity, IMSI, or the international mobile equipment identity, IMEI, or the international mobile equipment identity together with the software version number, IMEISV or the CTS Mobile Subscriber Identity CTSMSI (see GSM 03.03).

The Mobile Identity information element is coded as shown in figure 10.5/GSM 04.08, table 10.8/GSM 04.08 and table 10.4/GSM 04.56.

Table 10.4/GSM 04.56: Mobile Identity information element

+——————————————————–+

 Type of identity (octet 3) 

 Bits 

 3 2 1 

 0 0 1 IMSI 

 0 1 0 IMEI 

 0 1 1 IMEISV 

 1 0 1 CTSMSI 

 

 All other values are defined in GSM 04.08 or reserved. 

 

 

 Identity digits (octet 3 etc. figure 10.5 GSM 04.08) 

 For CTSMSI, this field is coded using hexadecimal 

 coding. The 22 bits of the CTSMSI are padded with 6 

 leading zeroes for having a 5 hexadecimal digits 

 identity as follow: 

 original CTSMSI: xx xxxx xxxx xxxx xxxx xxxx 

 padded CTSMSI: 0000 00xx xxxx xxxx xxxx xxxx xxxx 

 hex coded CTSMSI: H1 H2 H3 H4 H5 H6 H7 

 

 The Odd/even indication shall be set to odd for 

 CTSMSI identity. 

+——————————————————–+

10.5.2 Radio Resource management information elements

10.5.2.1 CTSMSI

The purpose of the CTSMSI information element is to provide the CTS‑MS Subscriber Identity for paging purposes.

The CTSMSI information element is coded as shown in figure 10.1/GSM 04.56.

The CTSMSI is a type 3 information element with 3 octets length.

8 7 6 5 4 3 2 1

+———————————————–+

  CTSMSI IEI  octet 1

+—–┼—————————————–

 0 │ 0   octet 2

spare│spare CTSMSI value 

+—–┴—————————————–

  octet 3

 CTSMSI value (contd) 

+———————————————–

  octet 4

 CTSMSI value (contd) 

+———————————————–+

Figure 10.1/GSM 04.56 CTSMSI information element

Table 10.5/GSM 04.56: CTSMSI information element

CTSMSI value (octet 2, 3 and 4)

Bit 6 of octet 2 is the most significant bit and bit 1 of octet 4 is the least significant bit.

The coding of the CTSMSI shall be done according to GSM 03.03. The length is 22 bits.

NOTE: For purposes other than paging the CTSMSI should be provided using the mobile identity information element.

10.5.2.2 TFH General Parameters

The purpose of the TFH General Parameters information element is to provide the VA and VV vectors used in the hopping sequence.

8 7 6 5 4 3 2 1

+———————————————–+

  TFH General Parameters IEI  octet 1

+—–┼—————————————–

         octet 2

 v15  v14  v13  v12  v11  v10  v9  v8 

+—–┼—–┼—–┼—–┼—–┼—–┼—–┼—–

         octet 3

 v7  v6  v5  v4  v3  v2  v1  v0 

+———————–┼———————–

   octet 4

 a15  a14 

+———————–┼———————–

   octet 5

 a13  a12 

+———————–┼———————–

   octet 6

 a11  a10 

+———————–┼———————–

   octet 7

 a9  a8 

+———————–┼———————–

   octet 8

 a7  a6 

+———————–┼———————–

   octet 9

 a5  a4 

+———————–┼———————–

   octet 10

 a3  a2 

+———————–┼———————–

   octet 11

 a15  a0 

+———————————————–+

Figure 10.2/GSM 04.56 TFH General Parameters information element

10.5.2.3 TFH Current Parameters

The purpose of the TFH Current Parameters information element is to provide the CSR value, the TFH Counter 1 value, the TFH Counter 2 values, and the VC vector used in the hopping sequence.

8 7 6 5 4 3 2 1

+———————————————–+

  TFH Current Parameters IEI  octet 1

+———————————————–

 Length of TFH Current Parameters contents  octet 2

 (high part) 

+———————————————–

 CSR  octet 3

 (high part) 

+———————————————–

 CSR  octet 4

 (low part) 

+———————————————–

 Counter 1  octet 5

 (high part) 

+———————————————–

 Counter 1  octet 6

 (low part) 

+———————————————–

 Counter 2  octet 7

 (high part) 

+———————————————–

 Counter 2  octet 8

 (low part) 

+———————————————–

  octet 9

 VC 

+———————————————–

. .

. .

+———————————————–

 VC  octet n

 

+———————————————–+

Figure 10.3/GSM 04.56: TFH Current Parameters information element

Table 10.6/GSM 04.56: TFH Current Parameters information element

CSR (octets 3 and 4)

Current value of the shift register

Counter 1 (octets 5 and 6)

Current value of the counter 1 padded to a 16 bits value

Counter 1 (octets 7 and 8)

Current value of the counter 8 padded to a 16 bits value

VC (octets 9 to n)

Base sequence for the hopping sequence. See GSM 05.02

10.5.2.4 CTS Channel Description

The purpose of the CTS Channel Description information element is to provide a description of an allocable channel together with its SACCH.

The CTS Channel Description information element is coded as shown in figure 10.19/GSM 04.08, table 10.23/GSM 04.08 and table 10.5x/GSM 04.56.

Table 10.7/GSM 04.56: CTS Channel Description information element

Channel Type and TDMA offset (octet 2) shall be set to TCH/F and ACCHs by the CTS‑FP. CTS‑MSs shall also support all value defined in table 10.23/GSM 04.08.

TSC (octet 3) shall be set to 0 by the CTS‑FP and ignored by the CTS‑MSs.

HSN (octet 4 bit 6 to 1) shall be set to 0 by the CTS‑FP and ignored by the CTS‑MS

10.5.2.5 CTS Access Request Reference

The purpose of the CTS Access Request Reference information element is to provide the access request information used in the CTSARCH channel.

The CTS Access Request information elements coded as shown in figure 10.4/GSM 04.56 and table 10.8/GSM 04.56.

The CTS Access Request is a type 3 information element with 5 octets length.

8 7 6 5 4 3 2 1

+———————————————–+

│ │ Access Request Reference IEI │ octet 1

+—–┴—————————————–

│ │ octet 2

│ Access Request Information │

+———————————————–

│ │ octet 3

│ Access Request Information │

+———————————————–

│ │ octet 4

│ Access Request Information │

+———————————————–

│Acc. │ │ octet 5

│Rq. I│ │

+—–┴—————————————–+

Figure 10.4/GSM 04.56: Access request Reference information element

Table 10.8/GSM 04.08: Access request Reference information element

Access Request Information

This is an unformatted 25 bits field. Typically the contents of this field are coded the same as the CTS ACCESS REQUEST message.

10.5.2.6 CTS L1 information

The purpose of the CTS L1 information information element is to provide the TDMA frame number of the last burst containing the message.

8

7

6

5

4

3

2

1

CTS L1 information IEI

octet 1

T1

(high)

octet 2

T1

(low)

T2

octet 3

0

spare

0

spare

T3

Octet 4

Figure 10.5/GSM 04.56 CTS L1 information information element

T1 (octet 2 and 3):

It is coded as the binary representation of FN div(26*51). Bit 8 of octet 2 is the most significant bit and bit 7 of octet 3 is the least significant bit.

T2 (octet 3):

It is coded as the binary representation of FN mod 26.

T3 (octet 4):

It is coded as the binary representation of FN mod 51.

The computation of the FN is given in GSM 05.10.

Table 10.5GSM 04.56: CTS L1 information information element

10.5.2.7 Information Transfert Capability

The purpose of the Information Transfert Capability information element is to convey the information transfert capability. See figure 10.x/GSM 04.56 and table 10.72/GSM 04.08.

8 7 6 5 4 3 2 1

+———————————————–+

│ │ Info. Transfert │ 0 │Info. Transfert │ octet 1

│ │ Capability IEI │Spare│Capability │

+—–┴—————–┴—–┴—————–+

Figure 10.6/GSM 04.56 Information Transfert Capability information element

10.5.2.8 BCD Display

The purpose of the BCD Display information element is to convey a BCD coded telephone number.

8 7 6 5 4 3 2 1

+———————————————–+

│ │ BCD Display IEI │ octet 1

+—–┴—————————————–

│ │ octet 2

│ Length of BCD Display contents │

+———————————————–

│ │ │ octet 3

│ digit 2 │ digit 1 │

+———————–┼———————–

. . .

. . .

+———————–┼———————–

│ │ │ octet n

│ digit 2n │ digit 2n-1 │

+———————–┴———————–+

Figure 10.7/GSM 04.56: BCD Display information element

Table 10.9/GSM 04.08: BCD Display information element

Digits are encoded as described in table 10.81/GSM 04.08 except for digit 1110:
Bits

4 3 2 1

1 1 1 0 + (plus sign)

10.5.2.9 AFA Interference Level

The purpose of the AFA Interference Level information element is to provide the results of the interference measurements made by the CTS‑MS on the current serving CTS‑cell.

8 7 6 5 4 3 2 1

+———————————————–+

  AFA Interference Level IEI  octet 1

+———————————————–

 Length of AFA Interference Level contents  octet 2

 (high part) 

+———————————————–

 0 0   octet 3

 Spare  Interference level[1] 

+———–┼———————————–

 0 0   octet 4

 Spare  Interference level[2] 

+———–┼———————————–

. .

. .

+———–┼———————————–

 0 0   octet N + 2

 Spare  Interference level[N] 

+———–┴———————————–+

Figure 10.8/GSM 04.56: AFA Interference Level information element

Table 10.10/GSM 04.56: AFA Interference Level information element

Interference level[k] (octet k + 2)
Received interference level for the kth carrier of the AFA monitoring frequency list (see GSM 05.08).

10.5.2.10 AFA Monitoring Cycles

The purpose of the AFA Monitoring Cycles information element is to specify a number of AFA monitoring cycles.

8 7 6 5 4 3 2 1

+———————————————–+

  AFA Monitoring Cycles IEI  octet 1

+———————————————–

 0 0 0 0 0 0  NAMC  octet 2

 spare (high part)

+———————————————–

 NAMC  octet 3

 (low part) 

+———————————————–+

Figure 10.10/GSM 04.56: AFA Monitoring Cycles information element

Table 10.11/GSM 04.56: AFA Monitoring Cycles information element

NAMC (octet 2 and 3)

Number of AFA monitoring cycles (see GSM 05.08).

10.5.2.11 OFO Measurement Results

The purpose of the OFO Measurement Results is to provide the results of the OFO measurements made by the CTS‑MS on the current serving CTS‑cell. If, due to octet boundaries, some bits are not used at the end of the last octet, these bits must be set to 0.

8 7 6 5 4 3 2 1

+———————————————–+

  OFO Measurement Result IEI  octet 1

+———————————————–

 Length of OFO Measurement Results contents  octet 2

 

+———————————————–

 OFO  OFO value[1]  octet 3

 status[1]  (high part) 

+———————————————–

OFO 1 OFO  OFO value[2]  octet 4

(low) status[2]  (high part) 

+———————————————–

OFO Value 2 OFO  OFO value[3]  octet 5

(low part)  status[3]  (high part) 

+———————————————–

. .

. and so on. .

+———————————————–+

Figure 10.11/GSM 04.56: OFO Measurement Results information element

Table 10.12/GSM 04.56: OFO Measurement Results information element

OFO value[k]

OFO measurement value for the kth carrier of the OFO measurement BCCH list (see GSM 05.08).

OFO status[k]

OFO measurement status of the kth BCCH carrier:

Bits

2 1

0 0 measurement OK

0 1 measurement failed

1 0 measurement not performed

10.5.2.12 Paging type

The purpose of the Paging type information element is to provide the CTS‑MS Subscriber Identity for paging purposes.

The Paging type information element is coded as shown in figure 10.1/GSM 04.56.

The Paging type is a type 3 information element with 2 octets length.

8

7

6

5

4

3

2

1

Paging type IEI

octet 1

AC field

0

spare bits

octet 2

Figure 10.1/GSM 04.56: Paging type information element

Table 10.5/GSM 04.56: Paging type information element

AC field (octet 2, bits 8,7 and 6)

000 Start paging procedure

100 Start Alive Check procedure

other values are reserved for future use

Octet 2, bits 5 to 1 are spare bits.

10.5.2.13 CTS selection parameters

The purpose of the CTS selection parameters information element is to provide the value of the parameters needed for the FP selection procedure.

The CTS selection parameters information element is coded as shown in figure 10.22/GSM 04.56 and table 10.22/GSM 04.56.

The CTS selection parameters is a type 3 information element with 3 octets length.

8 7 6 5 4 3 2 1

CTS selection parameters IEI

octet 1

O

spare

0

spare

0

spare

CTS MS MAX TXPWR value

octet 2

0

spare

0

spare

CTS RXLEV ACCESS MIN

octet 3

Figure 10.22/GSM 04.56 CTS: selection parameters information element

CTS MS MAX TXPWR (octet 2):

It is coded as the binary representation of the maximum authorised

output power control level a CTS-MS shall use with this CTS-FP.

Range: 0 to 31 (See TS GSM 05.08)

CTS RXLEV ACCESS MIN (octet 3):

It is coded as the binary representation of the minimum received signal level at the MS for which it is permitted to access the CTS FP.

Range: 0 to 63 (See TS GSM 05.08)

Table 10.22GSM 04.56: CTS selection parameters information element

10.5.2.14 CTS RR parameters

The purpose of the CTS RR parameters information element is to provide the value of the parameters needed for the CTS dedicated and idle modes.

The CTS RR parameters information element is coded as shown in figure 10.23/GSM 04.56 and table 10.23/GSM 04.56.

The CTS RR parameters is a type 3 information element with 5 octets length.

8 7 6 5 4 3 2 1

CTS selection parameters IEI

octet 1

0

spare

0

spare

CTS CELL RESELECT OFFSET

octet 2

0

spare

0

spare

0

spare

0

spare

CTS RADIO LINK TIMEOUT

octet 3

0

spare

0

spare

0

spare

0

spare

0

spare

Number of paging groups

octet 4

CTSPCH_DECOD

octet 5

Figure 10.23/GSM 04.56: CTS RR parameters information element

CTS CELL RESELECT OFFSET (octet 2):

It is coded as the binary representation of the offset in dB to be applied for the C2 CTS criterion.

Range: 0 to 63 (See TS GSM 05.08)

CTS RADIO LINK TIMEOUT (octet 3):

It is coded as the binary representation of the maximum value of the radio link counter.

Range: 0(4 SACCH blocks) to 15(64 SACCH blocks)(See TS GSM 05.08)

Number of paging groups (octet 4):

It is coded as the representation of the number of

multiframes period for transmission of CTS PAGING REQUEST to the

same paging subgroup (see TS GSM 05.02)

Range: 0 to 7 with

0 means 2 multiframes period and

2 means 9 multiframes period (refer to GSM 04.08 Table 10.29)

CTSPCH_DECOD (octet 5)

It is coded as the binary representation of the number of

non-decoded paging messages before declaring a downlink paging

failure (see GSM05.08).

Range: 1 to 255; 0 is a reserved value and shall not be sent by the CTS-FP

Table 10.23GSM 04.56: CTS RR parameters information element

10.5.2.15 Timeslot shifting parameters

The purpose of the Timeslot shifting parameters information element is to provide the value of the parameters

The Timeslot shifting parameters information element is coded as shown in figure 10.24/GSM 04.56 and table 10.24/GSM 04.56.

The Timeslot shifting parameters is a type 3 information element with 5 octets length.

8

7

6

5

4

23

2

1

Timeslot shifting parameters IEI

octet 1

TNSCO

0 0 0 0 0 0 0

Spare

octet 2

O

Spare

x0

0

spare

x1

octet 3

0

spare

x2

0

spare

x3

octet 4

Figure 10.24/GSM 04.56: Timeslot shifting parameters information element

TNSCO, TNS Couple Order (octet 2):

Bit

8

0 see TS GSM 05.03

1 see TS GSM 05.03

x0 (octet 3):

It is coded as the binary value of the parameter x0 needed to form

the timeslot shifting sequence

Range: 0 to 7 (see TS GSM 05.02)

x1 (octet 3):

It is coded as the binary value of the parameter x1 needed to form

the timeslot shifting sequenceRange: 0 to 7

Range: 0 to 7 (see TS GSM 05.02)

x2 (octet 4):

It is coded as the binary value of the parameter x2 needed to form

the timeslot shifting sequence

Range: 0 to 7 (see TS GSM 05.02)

x3 (octet 4):

It is coded as the binary value of the parameter x3 needed to form

the timeslot shifting sequence

Range: 0 to 7 (see TS GSM 05.02)

Table 10.24GSM 04.56: Timeslot shifting parameters information element

10.5.3 Mobility management information elements

10.5.3.1 Authentication parameter RIMS

The purpose of the Authentication Parameter RIMS information element is to provide the mobile station with a non-predictable number to be used to calculate the mutual initial key Kinit.

The Authentication Parameter RIMS information element is coded as shown in figure 10.12/GSM 04.56 and table 10.13/GSM 04.56.

The Authentication Parameter RIMS is a type 3 information element with 9 octets length.

8 7 6 5 4 3 2 1

+———————————————–+

 Authentication parameter RIMS IEI  octet 1

+———————————————–

 

 RIMS value  octet 2

:

:

  octet 9

 

+———————————————–+

Figure 10.12/GSM 04.56: Authentication Parameter RIMS information element

Table 10.13/GSM 04.56: Authentication Parameter RIMS information element

+—————————————————–+

 RIMS value (octet 2, 3,… and 9) 

 The RIMS value consists of 64 bits. Bit 8 of octet 

 2 is the most significant bit while bit 1 of octet 

 9 is the least significant bit. 

+—————————————————–+

10.5.3.2 Authentication parameter RIFP

The purpose of the Authentication Parameter RIFP information element is to provide the fixed part with a non-predictable number to be used to calculate the mutual initial key Kinit.

The Authentication Parameter RIFP information element is coded as shown in figure 10.13/GSM 04.56 and table 10.14/GSM 04.56.

The Authentication Parameter RIFP is a type 3 information element with 9 octets length.

8 7 6 5 4 3 2 1

+———————————————–+

 Authentication parameter RIFP IEI  octet 1

+———————————————–

 

 RIFP value  octet 2

:

:

  octet 9

 

+———————————————–+

Figure 10.13/GSM 04.56: Authentication Parameter RIFP information element

Table 10.14/GSM 04.56: Authentication Parameter RIFP information element

+—————————————————–+

 RIFP value (octet 2, 3,… and 9) 

 The RIFP value consists of 64 bits. Bit 8 of octet 

 2 is the most significant bit while bit 1 of octet 

 9 is the least significant bit. 

+—————————————————–+

10.5.3.3 Authentication parameter CH

The purpose of the Authentication Parameter CH information element is to provide the mobile station or the fixed part with a non-predictable number to be used to calculate the authentication response signature XRES and the ciphering key Kc.

The Authentication Parameter CH information element is coded as shown in figure 10.14/GSM 04.56 and table 10.15/GSM 04.56.

The Authentication Parameter CH is a type 3 information element with 17 octets length.

8 7 6 5 4 3 2 1

+———————————————–+

 Authentication parameter CH IEI  octet 1

+———————————————–

 

 CH value  octet 2

:

:

  octet 17

 

+———————————————–+

Figure 10.14/GSM 04.56: Authentication Parameter CH information element

Table 10.15/GSM 04.56: Authentication Parameter CH information element

+—————————————————–+

 CH value (octet 2, 3,… and 17) 

 The CH value consists of 128 bits. Bit 8 of octet 

 2 is the most significant bit while bit 1 of octet 

 17 is the least significant bit. 

+—————————————————–+

10.5.3.4 Authentication parameter XRES

The purpose of the authentication parameter XRES information element is to provide the fixed part or the mobile station with the authentication response signature calculated in the mobile station or in the fixed part.

The Authentication Parameter XSRES information element is coded as shown in figure 10.15/GSM 04.56 and table 10.16/GSM 04.56.

The Authentication Parameter XRES is a type 3 information element with 17 octets length.

8 7 6 5 4 3 2 1

+———————————————–+

 Authentication parameter XRES IEI  octet 1

+———————————————–

 

 XRES value  octet 2

:

:

  octet 17

 

+———————————————–+

Figure 10.15/GSM 04.56: Authentication Parameter XRES information element

Table 10.16/GSM 04.56: Authentication Parameter XRES information element

+—————————————————–+

 XRES value (octet 2, 3,… and 17) 

 The XRES value consists of 128 bits. Bit 8 of octet 

 2 is the most significant bit while bit 1 of octet 

 17 is the least significant bit. 

+—————————————————–+

10.5.3.5 Authentication parameter Kax

The purpose of the Authentication Parameter Kax information element is to provide the mobile station with the authentication key.

The Authentication Parameter Kax information element is coded as shown in figure 10.16/GSM 04.56 and table 10.17/GSM 04.56.

The Authentication Parameter Kax is a type 3 information element with 17 octets length.

8 7 6 5 4 3 2 1

+———————————————–+

 Authentication parameter Kax IEI  octet 1

+———————————————–

 

 Kax value  octet 2

:

:

  octet 17

 

+———————————————–+

Figure 10.16/GSM 04.56: Authentication Parameter Kax information element

Table 10.17/GSM 04.56: Authentication Parameter Kax information element

+—————————————————–+

 Kax value (octet 2, 3,… and 17) 

 The Kax value consists of 128 bits. Bit 8 of octet 

 2 is the most significant bit while bit 1 of octet 

 17 is the least significant bit. 

+—————————————————–+

10.5.3.6 Fixed part Identity

The purpose of the Fixed part Identity information element is to provide either the international fixed part subscriber identity, IFPSI or the international fixed part equipment identity, IFPEI.

The IFPSI shall not exceed 15 digits, the IFPEI is composed of 16 digits (see GSM 03.03).

The Fixed part Identity information element is coded as shown in figure 10.17/GSM 04.56 and table 10.18/GSM 04.56.

The Fixed part Identity is a type 4 information element with a minimum length of 3 octets and 11 octets length maximal.

8 7 6 5 4 3 2 1

+———————————————–+

  Fixed part Identity IEI  octet 1

+———————————————–

 

 Length of fixed part identity contents  octet 2

+———————————————–

 odd/  

 Identity digit 1 even  Type of identity octet 3

 indic 

+———————–+———————–

  

 Identity digit p+1  Identity digit p  octet 4*

+———————————————–+

Figure 10.17/GSM 04.56: Fixed part Identity information element

Table 10.18/GSM 04.56: Fixed part Identity information element

+——————————————————–+

 Type of identity (octet 3) 

 Bits 

3 2 1

 0 0 1 IFPSI 

 0 1 0 IFPEI 

 

 All other values are reserved. 

 

 Odd/even indication (octet 3) 

 Bit 

4

 0 even number of identity digits and also when 

 1 odd number of identity digits 

 

 Identity digits (octet 3 etc) 

 For the IFPSI, IFPEI this field is coded using BCD 

 coding. If the number of identity digits is even then 

 bits 5 to 8 of the last octet shall be filled with 

 an end mark coded as "1111". 

+——————————————————–+

10.5.3.7 CTS mobile group list

The purpose of the CTS mobile group list information element is to provide a list containing up to 8 CTSMSI.The CTS mobile group list information element is coded as shown in figure 10.18/GSM 04.56 and table 10.19/GSM 04.56.

The CTS mobile group list is a type 4 information element with a minimum length of 5 octets and 26 octets length maximal.

8 7 6 5 4 3 2 1

+———————————————–+

  CTS mobile group list IEI  octet 1

+———————————————–

 Length of CTS mobile group list contents  octet 2

+———————————————–

 CTSMSI 1 (first octet)  octet 3

+———————————————–

 CTSMSI 1 (second octet)  octet 3

+———————————————–

 CTSMSI 1 (third octet)  octet 3

+———————————————–

:

:

+———————————————–

 CTSMSI n (third octet)  octet m

+———————————————–+

Figure 10.18/GSM 04.56: CTS mobile group list information element

Table 10.19/GSM 04.56: CTS mobile group list information element

+——————————————————–+

 CTSMSI (octets 2, 3, and n) 

 Each CTSMSI consists of 3 octets. They are defined in 

 subclause 10.5.2.1. 

 The first one corresponds to octet 2 in 10.5.2.1, the 

 second one to octet 3 and the third one to octet 4. 

+——————————————————–+

10.5.3.8 Following attach request

The purpose of the Following attach request information element is to indicate that an attach request may be done on an existing RR connection.

The Following attach request information element is coded as shown in figure 10.19/GSM 04.56.

The Following attach request is a type 2 information element.

8 7 6 5 4 3 2 1

+———————————————–+

 Following attach request IEI  octet 1

+———————————————–+

Figure 10.19/GSM 04.56 Following attach request information element

10.5.3.9 Access right identity

The purpose of the Access right identity information element is to provide the FPBI and the length of its significant part for access to this fixed part.

The Access right identity information element is coded as shown in figure 10.20/GSM 04.56 and table 10.20/GSM 04.56.

The Access right identity is a type 3 information element with 4 octets length.

8 7 6 5 4 3 2 1

+———————————————–+

  Access right identity IEI  octet 1

+———————————————–

 FPBI Length Identifier  FBPI (high)  octet 2

+———————————————–

 FPBI (middle)  octet 3

+———————————————–

 FPBI (low)  octet 4

+———————————————–+

Figure 10.20/GSM 04.56: Access right identity information element

Table 10.20/GSM 04.56: Access right identity information element

+——————————————————–+

 FBPI Length Indicator (octet 2 bit 8 to 4) 

 The FLI is the length in bits of the FPBI significant 

 part. 

 FBPI (octet 2 bit 3 to 1 and octets 3 and 4) 

 The FPBI value consists of 19 bits. Bit 3 of octet 2 

 is the most significant bit while bit 1 of octet 4 is 

 the least significant bit. 

+——————————————————–+

10.5.3.10 TC3252

The purpose of the TC3252 information element is to provide the value of the timer TC3252.

The TC3252 information element is coded as shown in figure 10.21/GSM 04.5656 and table 10.21/GSM 04.56.

The TC3252 is a type 3 information element with 2 octets length.

8 7 6 5 4 3 2 1

+———————————————–+

 TC3252 IEI  octet 1

+———————————————–

 TC3252 value  octet 2

+———————————————–+

Figure 10.21/GSM 04.56: TC3252 information element

Table 10.21GSM 04.56: TC3252 information element

+——————————————————–+

 TC3252 value 

 It is the value in deciminutes (6 seconds) of the 

 timer TC3252. 

+——————————————————–+

10.5.3.11 Attach type

The purpose of the Attach type information element is to indicate whether a normal attach or a reattach is wanted. It may also indicate that a follow-on request has been received from the mobile station CM layer.

The Attach type information element is coded as shown in figure 10.22/GSM 04.56 and table 10.22/GSM 04.56.

The Attach type is a type 1 information element.

8

7

6

5

4

3

2

1

Attach type IEI

FOR

0

spare

Attach

type

octet 1

Figure 10.22/GSM 04.56: Attach type information element

FOR (octet 1):

Bit 4

0 No Follow On Request pending

1 Follow On Request pending

Attach type (octet 2)

Bits

2 1

0 0 Normal attach procedure

0 1 Re-attach procedure

1 0 Reserved

1 1 Reserved

Table 10.22GSM 04.56: Attach type information element

10.5.4 Call control information elements

Call Control Information Elements are defined in GSM 04.08. The few exceptions for CTS specific procedures are defined in the following subclauses.

10.5.4.1 Called party BCD number

The called party BCD number information element is modified in order to support the CTS internal call procedure.

See table 10.22/GSM 04.56.

Table 10.22/GSM 04.56: Called party BCD number

+———————————————————+

 Numbering plan identification (octet 3) 

 

 Number plan (applies for type of number = 000, 

 001, 010 and 100) 

 Bits 

 4 3 2 1 

 0 0 0 0 see GSM 04.08 

 0 0 0 1 see GSM 04.08 

 0 0 1 1 see GSM 04.08 

 0 1 0 0 see GSM 04.08 

 1 0 0 0 see GSM 04.08 

 1 0 0 1 see GSM 04.08 

 1 0 1 1 CTS internal numbering plan 

 1 1 1 1 see GSM 04.08 

 

 All other values are reserved. 

+———————————————————+

10.5.4.2 Calling party BCD number

The calling party BCD number information element is modified in order to support the CTS internal call procedure.

See table 10.23/GSM 04.56.

Table 10.23/GSM 04.56: Calling party BCD number

+———————————————————+

 Numbering plan identification (octet 3) 

 

 Number plan (applies for type of number = 000, 

 001, 010 and 100) 

 Bits 

 4 3 2 1 

 0 0 0 0 see GSM 04.08 

 0 0 0 1 see GSM 04.08 

 0 0 1 1 see GSM 04.08 

 0 1 0 0 see GSM 04.08 

 1 0 0 0 see GSM 04.08 

 1 0 0 1 see GSM 04.08 

 1 0 1 1 CTS internal numbering plan 

 1 1 1 1 see GSM 04.08 

 

 All other values are reserved. 

+———————————————————+

10.5.4.3 Keypad facility

The purpose of the keypad facility information element is to convey IA5 characters, e.g. entered by means of a terminal keypad. A specific character is defined for CTS to transmit the hook flash request. This character is not used in the standard IA5 sense.

The keypad facility information element is coded as shown in figure 10.22/GSM 04.56 and table 10.24/GSM 04.56.

The keypad facility is a type 3 information element with 2 octets length.

8 7 6 5 4 3 2 1

+———————————————–+

¼ ¼ Keypad facility IEI ¼ octet 1

+—–+—————————————–¼

¼Spare¼ ¼

¼ 0 ¼ Keypad information (IA5 character) ¼ octet 2

+———————————————–+

Figure 10.22/GSM 04.56: Keypad facility information element

NOTE: In CTS this information element is only used to transfer one DTMF digit (0, 1, … , 9, A, B, C, D, *, #) or a hook flash request as one IA5 character.

Table 10.24/GSM 04.56: Keypad information

Keypad information is encoded as described in CCITT T.50/ISO 646 except for the following value:
Bits

7 6 5 4 3 2 1

0 0 1 0 1 0 1 hook flash (registry call)