Cell Change - GSM

 

 

 

Packet Cell Change from GSM to WCDMA

 

Step

Direction

Message

Channel

Comments

1

UE <--> NW

< Packet Call in GSM/GPRS >

 

 

2

UE <-- NW

PACKET_CELL_CHANGE_ORDER (Downlink)

PACCH

GSM_GRR_CONTROL_REQ

3

UE <--> NW

< PRACH/RRC Connection Setup in WCDMA >

   

4

UE <--> NW

< Complete Attach to WCDMA >

   

5

UE <--> NW

<  Radio Bearer Setup but no PDP Activation might be required since it would use PDP established in GSM >

   

6

UE <--> NW

  < Packet Traffic >

 

 

 

GSM RLC/MAC: PACKET_CELL_CHANGE_ORDER (Downlink)

 

DLT: 147, Payload: gsm_rlcmac_dl (Radio Link Control, Medium Access Control, 3GPP TS44.060)

GSM RLC/MAC: PACKET_CELL_CHANGE_ORDER (1) (Downlink)

    01.. .... = Payload Type (DL): RLC/MAC block contains an RLC/MAC control block that does not include the optional octets of the RLC/MAC control header (1)

    ..00 .... = RRBP: Reserved Block: (N+13) mod 2715648 (0)

    .... 1... = S/P: RRBP field is valid

    .... .000 = USF: 0

    PACKET_CELL_CHANGE_ORDER (1) (downlink)

        0000 01.. = MESSAGE_TYPE (DL): PACKET_CELL_CHANGE_ORDER (1)

        .... ..00 = PAGE_MODE: Normal Paging (0)

        ID

            10.. .... Choice: PacketCellChangeOrderID (2)

            PacketCellChangeOrderID

                ..11 0000  0000 0000  0000 0000  0010 0000  00.. .... = TLLI: 3221225600

        ..1. .... Union:UnionType

        u.Target_Cell_3G

            ...0 0... 0x00

            .... .1.. = IMMEDIATE_REL: 1

            .... ..1. Exist_FDD_Description

            FDD_Target_Cell

                .... ...1  0011 0010  0100 0... = FDD_ARFCN: 9800

                .... .0.. = DIVERSITY: 0

                .... ..0. Exist_Bandwith_FDD

                .... ...0  0000 1001 = SCRAMBLING_CODE: 9

            0... .... Exist_TDD_Description

            .0.. .... Exist_AdditionsR5

        Padding Bits

            ..10 1011  0010 1011  0010 1011  0010 1011 Padding

            0010 1011  0010 1011  0010 1011  0010 1011 Padding

            0010 1011  0010 1011  0010 1011  0010 1011 Padding

            0010 1011 Padding

 

HEX : 48 04 B0 00 00 20 27 32 40 09 2B 2B 2B 2B 2B 2B 2B 2B 2B 2B 2B 2B 2B

 

 

Packet Cell Change from WCDMA to GSM

 

Step

Direction

Message

Channel

Comments

1

UE <--> NW

< Packet Call in WCDMA >

 

 

2

UE <-- NW

cellChangeOrderFromUTRAN

DCCH

 

3

UE <--> NW

< Channel Request/Immediate Assignment in GSM >

   

4

UE <--> NW

< Complete Attach to GSM >

   

5

UE <--> NW

<  PDP Activation might be required since it would use PDP established in WCDMA >

   

6

UE <--> NW

  < Packet Traffic >

 

 

 

 

cellChangeOrderFromUTRAN

 

DLT: 147, Payload: rrc.dl.dcch (Radio Resource Control (RRC) protocol)

DL-DCCH-Message

    integrityCheckInfo

        messageAuthenticationCode: d7297f3a

        rrc-MessageSequenceNumber: 2

    message: cellChangeOrderFromUTRAN (2)

        cellChangeOrderFromUTRAN: r3 (0)

            r3

                cellChangeOrderFromUTRAN-IEs

                    rrc-TransactionIdentifier: 0

                    interRAT-TargetCellDescription

                        technologySpecificInfo: gsm (0)

                            gsm

                                bsic

                                    ncc: 0

                                    bcc: 1

                                frequency-band: dcs1800BandUsed (0)

                                bcch-ARFCN: 1

                                ncMode: 00 [bit length 3, 5 LSB pad bits, 000. .... decimal value 0]

 

HEX : EB 94 BF 9D 10 80 10 40 08