11.2.40 MBMS Neighbouring Cell Information

3GPP44.060General Packet Radio Service (GPRS)Mobile Station (MS) - Base Station System (BSS) interfaceRadio Link Control / Medium Access Control (RLC/MAC) protocolRelease 17TS

This optional message is sent by the network on the PACCH to provide details of the bearer allocated to a particular MBMS session in a neighbouring cell. This message shall not be segmented across more than one RLC/MAC control block. If not all information fits into one instance of the MBMS NEIGHBOURING CELL INFORMATION message, the information can be distributed over more than one instance of the message.

Message type: MBMS NEIGHBOURING CELL INFORMATION

Direction: network to mobile station

Classification: distribution message

Table 11.2.40.1: MBMS Neighbouring Cell Information information elements

< MBMS Neighbouring Cell Information message content > ::=

< PAGE_MODE : bit (2) >

{ 1 < NEIGHBOUR_CELL_INDEX : bit (7) >

{ 0 | 1 < BSIC : bit (6) > }

< MBMS_PTM_CHANGE_MARK : bit (2) >

{ 1

< Length of MBMS Bearer Identity : bit (3) >

< MBMS Bearer Identity : bit (val (Length of MBMS Bearer Identity)) >

< Absence cause: bit (2) >

} ** 0 — End of list of MBMS bearers for which no p-t-m channel description is given in the neighbour cell

{ 1 < MBMS Frequency List : < MBMS Frequency List struct > > } **0

{ 1 < MBMS p-t-m Frequency Parameters : < MBMS p-t-m Frequency Parameters struct > >

< DOWNLINK_TIMESLOT_ALLOCATION : bit (8) > — default value

{ 1 < Length of Serving MBMS Bearer Identity : bit (3) >

< Serving MBMS Bearer Identity : bit (val (Length of Serving MBMS Bearer Identity)) >

< Length of Neighbour MBMS Bearer Identity : bit (3) >

< Neighbour MBMS Bearer Identity : bit (val (Length of Neighbour MBMS Bearer Identity)) >

{ 0 | 1 < EGPRS Window Size : < EGPRS Window Size IE >> }

{ 0 | 1 < DOWNLINK_TIMESLOT_ALLOCATION : bit (8) > } — specific value

{ 0 | 1 < TIMESLOT_ALLOCATION_UPLINK_FEEDBACK_CHANNEL : bit (3) > }

{ 0 | 1 < MBMS Radio Bearer Starting Time : < bit (16) > > }

< MBMS In-band Signalling Indicator : < MBMS In-band Signalling Indicator IE > >

{ 0 | 1 < NPM Transfer Time : bit (5) > }

} ** 0 — End of list of MBMS bearer descriptions sharing the same PDCH (frequency parameters)

} ** 0 — End of list of PDCHs for this cell

{ 0 | 1 < PBCCH information : < PBCCH information struct > > }

} ** 0 — End of list of neighbouring cells

{ null | 0 bit** = < no string > — Receiver compatible with earlier release

| 1 — Rel-7 additions

{ 1 { 0 | 1 < USF : bit (3) > — choice bit indicates presence or not of parameters for the MBMS bearer

{ 0 | 1 < MPRACH Control Parameters : < MPRACH Control Parameters IE > > }

}

} ** 0 — End of list of MBMS bearers.

— The list of MBMS bearers is ordered as described by the loops in the earlier releases part.

}

< padding bits >

! < Distribution part error : bit (*) = < no string > > ;

< PBCCH information struct > :: =

< Pb : bit (4) >
 < TSC : bit (3) >

< TN : bit (3) >

{ 00 — non-hopping PBCCH on BCCH carrier
 | 01 < ARFCN : bit (10) > — non-hopping PBCCH

| 1 — hopping PBCCH, frequency parameters from an MBMS bearer description for this cell

< Length of Neighbour MBMS Bearer Identity : bit (3) >
< Neighbour MBMS Bearer Identity : bit (val (Length of Neighbour MBMS Bearer Identity)) >

} ;

< MBMS Frequency List struct > :: =

< FREQ_LIST_NUMBER : bit (2) >

< Length of Frequency List contents : bit (4) >

< Frequency List contents : octet (val(Length of Frequency List contents) + 3) > ;

< MBMS p-t-m Frequency Parameters struct > :: =

< TSC : bit (3) >

{ 0 < ARFCN : bit (10 >

| 1 < MAIO : bit (6) >

< HSN : bit (6) >

< FREQ_LIST_NUMBER : bit (2) > } ;

Table 11.2.40.2: MBMS Neighbouring Cell Information information element details

PAGE_MODE (2 bit field)
This field is defined in sub-clause 12.20 and gives the PAGE_MODE parameter valid in the serving cell.

NEIGHBOUR_CELL_INDEX (7 bit field)
This information element is the index within the GSM Neighbour Cell list (defined in sub-clause 5.6.3.2) of the cell for which information is provided.

If the mobile station has not completed the construction of the GSM Neighbour Cell list (i.e. before the MS has acquired the complete GSM Neighbour Cell list from the BCCH messages, in case the PBCCH is not allocated in the cell), it shall not disregard this message but store the information contained in it.

BSIC (6 bit field)

This optional field is needed to identify the neighbour cell in case the GSM Neighbour Cell list is only a frequency list, see 3GPP TS 44.060 sub-clause 5.6.3.2.

MBMS_PTM_CHANGE_MARK (2 bit field)

This field contains the change mark value for the information given for a specific neighbouring cell. This information is used to combine information from multiple instances of the MBMS Neighbouring Cell Information message.

MBMS Bearer Identity (1-5 bit field)
This field contains the Bearer identity for the MBMS session. This field is defined in sub-clause 12.34.

Absence cause (2 bit field)
This field indicates why the description of the MBMS bearer for the neighbour cell is not provided in the message.

00 Neighbour cell not in the service area for the MBMS service associated with this Bearer identifier
01 No p-t-m bearer established in the neighbour cell for the MBMS service associated with this Bearer identifier
10 p-t-m bearer established in the neighbour cell for this MBMS service, but the description cannot be provided
11 No information available for the MBMS service associated with this bearer identifier

Serving MBMS Bearer Identity (1-5 bit field)
This field contains the Bearer identity used by the MBMS session in the serving cell. This field is encoded as the MBMS Bearer Identity IE defined in sub-clause 12.34.

Neighbour MBMS Bearer Identity (1-5 bit field)
This field contains the Bearer identity used by the MBMS session in the neighbour cell. This field is encoded as the MBMS Bearer Identity IE defined in sub-clause 12.34.

MBMS p-t-m Frequency Parameters
This information provides a description of a hopping or non-hopping radio frequency channel . In case hopping frequency channel is decribed, a reference to a specified MBMS Frequency List shall be provided. If MBMS Frequency List has not been received by the MS, it shall store this information for possible later use in case such MBMS Frequency List is received.

TSC (3 bit field)
This field is the binary representation of the training sequence code, see 3GPP TS 45.002. Range: 0 to 7.

ARFCN (10 bit field)
This field is the binary representation of the absolute radio frequency channel number (ARFCN) defined in 3GPP TS 45.005. Range 0 to 1023.

MAIO (6 bit field)
This field is the binary representation of the mobile allocation index offset (MAIO), see 3GPP TS 45.002. Range 0 to 63.

HSN (6 bit field)
This field is the binary representation of the hopping sequence number, see 3GPP TS 45.002. Range: 0 to 63.

FREQ_LIST_NUMBER (2 bit field)
This field is the binary identification of a MBMS Frequency List provided by an instance of this message, or the binary reference to such.Range: 0 to 3.

MBMS Frequency List
This information contains a set of radio frequency channels. This list shall be identified by the FREQ_LIST_NUMBER field.

Frequency List contents (variable length octet string)
This variable length octet string is the representation of a set of radio frequency channels defining a GPRS mobile allocation. The encoding of the octet string is defined by the value part of the type 4 information element Frequency List, defined in 3GPP TS 44.018. The allowed formats of the Frequency List information element are the bit map 0, 1024 range, 512 range, 256 range, 128 range and variable bit map formats.

DOWNLINK_TIMESLOT_ALLOCATION (8 bit field)
This information element describes which timeslots are assigned to the MBMS bearer in the neighbouring cell. This field is encoded as the Timeslot Allocation field defined in sub-clause 12.18.

The field following the Frequency Parameters information element shall refer to all the MBMS bearers described in the subsequent loop (default value). If this field is provided for a particular MBMS bearer, it refers only to that MBMS bearer (this specific value overrides the default value). Every MBMS bearer shall be assigned either the default value or a specific value.

TIMELOT_ALLOCATION_UPLINK_FEEDBACK_CHANNEL (3 bit field)
This field indicates the timeslot used for the uplink feedback channel in the neighbour cell. This field is coded as the binary representation of the timeslot number.

EGPRS Window Size
This information element is defined in sub-clause 12.5.2.

MBMS Radio Bearer Starting Time (16 bit field)
This field contains a starting time that indicates the frame number from which the data transfer on the assigned MBMS radio bearer may start. The MBMS Radio Bearer Starting Time is encoded as the value part of the type 3 information element Starting Time in 3GPP TS 44.018.

MBMS In-band Signalling Indicator
This information element contains the MBMS In-band Signalling Indicator. This information element is defined in sub-clause 12.45.

PBCCH information

This information, if present, describes the PBCCH location in the target cell. In case PBCCH is allocated in the target cell and can be described with this encoding, this information shall be included in the message.

USF (3 bit field)
This field identifies the USF value that identifies the MPRACH defined on the uplink feedback channel in the neighbour cell.

The list of MBMS bearers in the Rel-7 additions is ordered as described by the loops in the earlier releases part. The choice bit indicates for each MBMS bearer whether the parameters are present or not. 

MPRACH Control Parameters
This information element, if present, defines the access control parameters to be used on the MPRACH defined on the uplink feedback channel in the neighbour cell. This information element is defined in sub-clause 12.41.

NPM Transfer Time (5 bit field)

This field is defined in sub-clause 12.45a.