ETSI TS 143 246 V13.0.0 (2016-01)

ETSI TS 1143 246 V13.0.0 (201616-01)

TECHNICAL SPECIFICATIONION
Digital cellular telecocommunications system (Phahase 2+);
Multimedia Broadadcast/Multicast Service (MBBMS)
in the GERAN;
Stage 2
(3GPP TS 43.2.246 version 13.0.0 Release 13 13)

R
GLOBAL SYSTTEME FOR
MOBILE COMMUUNNICATIONS
3GPP TS 43.246 version 13.0.0 Release 13 1 ETSI TS 143 246 V13.0.0 (2016-01)

Reference
RTS/TSGG-0143246vd00
Keywords
GSM
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3GPP TS 43.246 version 13.0.0 Release 13 2 ETSI TS 143 246 V13.0.0 (2016-01)
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Foreword
This Technical Specification (TS) has been produced by ETSI 3rd Generation Partnership Project (3GPP).
The present document may refer to technical specifications or reports using their 3GPP identities, UMTS identities or
GSM identities. These should be interpreted as being references to the corresponding ETSI deliverables.
The cross reference between GSM, UMTS, 3GPP and ETSI identities can be found under
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Modal verbs terminology
In the present document "shall", "shall not", "should", "should not", "may", "need not", "will", "will not", "can" and
"cannot" are to be interpreted as described in clause 3.2 of the ETSI Drafting Rules (Verbal forms for the expression of
provisions).
"must" and "must not" are NOT allowed in ETSI deliverables except when used in direct citation.
ETSI
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Contents
Intellectual Property Rights . 2
Foreword . 2
Modal verbs terminology . 2
Foreword . 5
1 Scope . 6
2 References . 6
3 Definitions and abbreviations . 6
3.1 Definitions . 6
3.2 Abbreviations . 7
4 MBMS GERAN Architecture . 7
4.1 General . 7
4.2 GERAN A/Gb mode architecture . 7
4.2.1 Protocol structure . 7
4.2.2 void . 7
4.2.3 MBMS reception . 7
4.3 GERAN Iu mode architecture . 8
4.3.1 Protocol structure . 8
4.3.2 void . 8
4.3.3 MBMS reception . 8
5. MBMS channel structure. 9
5.1 Logical channels . 9
5.2 Physical channels . 9
5.2.1 General . 9
5.2.2 Coding schemes . 9
5.2.3 Mapping of MPRACH onto physical channels . 9
6 MBMS procedures in GERAN . 9
6.1 Resource management procedures . 9
6.1.1 Session start . 9
6.1.1.1 General . 9
6.1.1.1a Pre-notification . 10
6.1.1.2 Notification of session start . 10
6.1.1.2.1 General . 10
6.1.1.2.2 Mobile stations in packet idle mode or MAC-Idle state . 10
6.1.1.2.3 Mobile stations in packet transfer mode or MAC-Shared state and mobile stations in dual
transfer mode or MAC-DTM state . 11
6.1.1.2.4 Mobile stations in dedicated mode or MAC-Dedicated state . 11
6.1.1.3 Initial counting procedure . 12
6.1.1.4 MBMS bearer establishment . 14
6.1.1.5 Address assignment procedure . 15
6.1.1.6 Repetition of notifications of an on-going MBMS session . 15
6.1.2 MBMS channel reconfiguration . 15
6.1.3 MBMS channel release . 16
6.2 Mobility procedures . 16
6.2.1 Distribution of MBMS neighbouring cell information . 16
6.2.2 MBMS reception resumption after cell reselection . 17
6.2.2.1 Default behaviour . 17
6.2.2.2 Fast reception resumption . 17
6.2.3 Cell change . 18
6.3 MBMS data transfer for p-t-m transmission . 19
6.3.1 General . 19
6.3.1.1 Point-to-multipoint data transfer options . 19
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6.3.1.2 RLC protocol behaviour . 19
6.3.2 Block retransmission based on mobile station feedback . 19
6.4 Multiple sessions . 20
6.4.1 Transmission of multiple sessions . 20
6.4.2 Reception of multiple sessions. 21
6.5 Suspension/Resumption of the reception of an MBMS session . 22
6.6 Acquisition of system information and paging messages . 22
6.6.1 General . 22
6.6.2 Acquisition of system information . 22
6.6.3 Reception of paging messages . 23
7 Mobile Station requirements . 23
7.1 General requirements . 23
7.2 Mobile Station tasks . 23
7.3 Multislot capabilities . 24
7.4 MBMS notification for mobile stations in dedicated mode or packet transfer mode or dual transfer mode . 24
8 Network requirements . 25
8.1 General requirements . 25
8.2 MBMS notification for mobile stations in dedicated mode or packet transfer mode or dual transfer mode . 25
Annex A (normative): Requirements and recommendations . 26
A.1 General requirements and recommendations . 26
A.1.1 General requirements . 26
A.1.2 General recommendations . 27
A.2 Mobile Station requirements and recommendations . 27
A.2.1 Mobile Station requirements . 27
A.2.2 Mobile Station recommendations . 27
A.3 GERAN requirements and recommendations . 27
A.3.1 GERAN requirements . 27
A.3.1 GERAN recommendations . 27
Annex B (informative): Physical channel allocation scenarios . 28
B.1 Data transfer when no uplink feedback channel is established . 28
B.1.1 PBCCH not deployed, transmission with frequency hopping . 28
B.1.2 PBCCH not deployed, transmission without frequency hopping . 29
B.1.3 PBCCH deployed, transmission with frequency hopping . 29
B.2 Data transfer when an uplink feedback channel is established . 30
B.2.1 PBCCH not deployed, transmission with frequency hopping . 30
B.2.2 PBCCH not deployed, transmission without frequency hopping . 31
B.2.3 PBCCH deployed, transmission with frequency hopping . 32
Annex C (informative): Change history . 33
History . 35

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Foreword
rd
This Technical Specification has been produced by the 3 Generation Partnership Project (3GPP).
The contents of the present document are subject to continuing work within the TSG and may change following formal
TSG approval. Should the TSG modify the contents of the present document, it will be re-released by the TSG with an
identifying change of release date and an increase in version number as follows:
Version x.y.z
where:
x the first digit:
1 presented to TSG for information;
2 presented to TSG for approval;
3 or greater indicates TSG approved document under change control.
y the second digit is incremented for all changes of substance, i.e. technical enhancements, corrections,
updates, etc.
z the third digit is incremented when editorial only changes have been incorporated in the document.
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1 Scope
The present document is part of the Release 6 "Introduction of the Multimedia Broadcast Multicast Service
(MBMS) in GERAN" work item and it is linked to the corresponding 3GPP TS 22.146: "Multimedia
Broadcast/Multicast Service (MBMS); Stage 1" [3] and 3GPP TS 23.246: "Multimedia Broadcast/Multicast Service
(MBMS); Architecture and functional description" [5].
The purpose of the present document is to provide a stage 2 description of the changes required in existing
specifications for the "Introduction of the Multimedia Broadcast Multicast Service (MBMS) in GERAN" feature
for Release 6.
2 References
The following documents contain provisions which, through reference in this text, constitute provisions of the present
document.
• References are either specific (identified by date of publication, edition number, version number, etc.) or
non-specific.
• For a specific reference, subsequent revisions do not apply.
• For a non-specific reference, the latest version applies. In the case of a reference to a 3GPP document (including
a GSM document), a non-specific reference implicitly refers to the latest version of that document in the same
Release as the present document.
[1] 3GPP TS 23.060: "General Packet Radio Service (GPRS); Service description; Stage 2".
[2] 3GPP TS 23.107: "Quality of Service (QoS) concept and architecture".
[3] 3GPP TS 22.146: "Multimedia Broadcast/Multicast Service (MBMS); Stage 1".
[4] 3GPP TS 22.246: "Multimedia Broadcast/Multicast Service (MBMS) user services; Stage 1".
[5] 3GPP TS 23.246: "Multimedia Broadcast/Multicast Service (MBMS); Architecture and functional
description".
[6] 3GPP TR 25.992: "Multimedia Broadcast/Multicast Service (MBMS); UTRAN/GERAN
requirements".
[7] 3GPP TS 25.346: "Introduction of Multimedia Broadcast/Multicast Service (MBMS) in the Radio
Access Network (RAN); Stage 2".
[8] 3GPP TS 45.002: "Multiplexing and multiple access on the radio path".
[9] 3GPP TS 45.008: "Radio subsystem link control".
[10] 3GPP TS 43.022: "Functions related to Mobile Station (MS) in idle mode and group receive
mode".
3 Definitions and abbreviations
3.1 Definitions
For the purposes of the present document, the terms and definitions given in 3GPP TS 22.146 [3] and the following
apply.
Dedicated MBMS Notification: A mechanism in the network that allows the network to notify mobile stations in
dedicated mode of starting MBMS multicast sessions.
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MBMS radio bearer: In A/Gb mode, an MBMS radio bearer is defined as "point-to-multipoint".
MBMS channel: An MBMS channel consists of the physical resources assigned to one (several) MBMS service(s). In
A/Gb mode, an MBMS channel carries one (several) MBMS radio bearer(s) and may be on one (several) PDCH(s) with
GPRS and/or EGPRS TBF(s).
MBMS session: Defined in 3GPP TS 22.146 [3].
MBMS service: Defined in 3GPP TS 22.146 [3].
MBMS service class: An MBMS service class is defined as either Background or Streaming, according to 3GPP TS
23.107 [2].
MBMS notification: Defined in 3GPP TS 23.246 [5].
3.2 Abbreviations
For the purposes of the present document, the following abbreviations apply:
BM-SC Broadcast/Multicast Service Centre
MBMS Multimedia Broadcast/Multicast Service
MPRACH MBMS Packet Random Access Channel
p-t-p point-to-point
p-t-m point-to-multipoint
TMGI Temporary Mobile Group Identifier

4 MBMS GERAN Architecture
4.1 General
One new transmission mode exists to provide the MBMS service:
- Point-to-multipoint transmission (p-t-m)
Point-to-multipoint transmission is used to transfer MBMS specific information between the network and an
unspecified number of mobile stations. It is used for both broadcast and multicast modes of MBMS.
4.2 GERAN A/Gb mode architecture
4.2.1 Protocol structure
No modifications are required to the GPRS protocol stack (see 3GPP TS 23.060) for MBMS. However, some of the
radio protocols in the GERAN will require modifications to support MBMS p-t-m bearers.
4.2.2 void
4.2.3 MBMS reception
Table 4.2.3.1 shows whether a mobile station can support MBMS data reception according to its mode (packet idle
mode, packet transfer mode, dedicated mode or dual transfer mode) at the time of the MBMS bearer establishment i.e.
immediately prior to MBMS reception.
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Table 4.2.3.1: MBMS radio bearer available according to initial MAC mode and MBMS service

Packet idle mode Packet transfer mode Dedicated mode Dual transfer mode
(GMM-Standby or
GMM-Ready)
MBMS multicast
p-t-m p-t-p repair p-t-p repair (1) p-t-p repair
MBMS broadcast p-t-m Not specified (2) Not specified (3) Not specified (3)

1) A mobile station is moved to dual transfer mode on establishment of a TBF to request an MBMS p-t-p repair.
2) Support is optional in the mobile station.
3) Note that an MBMS broadcast service is only available on a p-t-m radio bearer.
4.3 GERAN Iu mode architecture
4.3.1 Protocol structure
No modifications are required to the GPRS protocol stack (see 3GPP TS 23.060 [1]) for MBMS. However, some of the
radio protocols in the GERAN will require modifications to support MBMS p-t-m bearers.
4.3.2 void
4.3.3 MBMS reception
Table 4.3.3.1 shows which type of MBMS radio bearer shall be assigned to the mobile station according to its RRC and
MAC states at the time of the MBMS bearer establishment i.e. immediately prior to MBMS reception.
Table 4.3.3.1: MBMS radio bearer available according to initial MAC and RRC states and MBMS
service
RRC-Idle RRC-GRA_PCH RRC-Cell_Shared RRC-Cell_Dedicated

MAC-Idle MAC-Idle MAC-Idle MAC-Shared MAC-Dedicated MAC-DTM

MBMS multicast p-t-m Not available (2) p-t-m p-t-p p-t-p (3) p-t-p
p-t-p (1) p-t-p (1)
MBMS broadcast p-t-m p-t-m p-t-m Not specified Not specified Not specified
(4) (5) (5)
1) A mobile station is moved to MAC-Shared state on establishment of an MBMS p-t-p radio bearer
2) A mobile station is moved to RRC-Cell_Shared state on establishment of an MBMS radio bearer (p-t-m or p-t-p)
3) A mobile station is moved to MAC-DTM state on establishment of an MBMS p-t-p radio bearer if it has no other
PS connections established
4) Support is optional in the mobile station
5) Note that an MBMS broadcast service is only available on a p-t-m radio bearer
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5. MBMS channel structure
5.1 Logical channels
For MBMS p-t-m transmission, the traffic data is carried on PDTCH (see 3GPP TS 45.002 [8]), whereas the control
data is carried on PACCH (see 3GPP TS 45.002 [8]).
A new logical channel is defined, the MPRACH, which may be used during the initial counting procedure (see sub-
clause 6.1.1.3). On the MPRACH, Packet Access Bursts or Extended Packet Access Bursts can be transmitted.
5.2 Physical channels
5.2.1 General
MBMS p-t-m radio bearers are transmitted on PDCH (see 3GPP TS 45.002 [8]).
On a PDCH it shall be possible to multiplex different MBMS p-t-m radio bearers and GPRS and/or EGPRS TBFs using
TFI.
5.2.2 Coding schemes
The existing GPRS and EGPRS coding schemes are used for MBMS.
An MBMS-capable mobile station shall support CS-1 to CS-4 and MCS-1 to MCS-9 in the downlink. A network
supporting MBMS may support only some of the coding schemes.
5.2.3 Mapping of MPRACH onto physical channels
The MPRACH may be mapped on any uplink PDCH.
The MPRACH is dynamically allocated in groups of four MPRACH blocks By (y=4x+i, i=0 ,., 3) corresponding to one
PDCH block Bx (x=0,.,11), indicated by a USF. The value of the USF allocated to the mobile station is signalled by
the network in the notification message.
6 MBMS procedures in GERAN
6.1 Resource management procedures
6.1.1 Session start
6.1.1.1 General
Upon receiving an MBMS SESSION START REQUEST message (or an MBMS SESSION UPDATE REQUEST
message for an ongoing MBMS broadcast session with an updated MBMS service area) from the SGSN, if the network
controls cells in the MBMS service area the network creates an MBMS Service Context (if not yet available for the
ongoing MBMS broadcast session), and acknowledges the SGSN using an MBMS SESSION START RESPONSE
message (or an MBMS SESSION UPDATE RESPONSE message). The network may receive an Allocation/Retention
Priority associated with the MBMS session in the MBMS SESSION START REQUEST message (or in the MBMS
SESSION UPDATE REQUEST message).
The network may use the Allocation/Retention Priority to prioritise between MBMS bearer services, and between
MBMS bearer services and non-MBMS bearer services. The network initiates the MBMS channel establishment in each
cell belonging to the MBMS service area where the network has decided to provide this MBMS service (and where the
MBMS channel has not yet been established in case of an ongoing MBMS broadcast session).
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The channel establishment procedure consists of the following steps:
- the optional pre-notification of the MBMS service which is starting a data transmission;
- the notification of all MBMS users in the cell of this MBMS service;
- an optional counting procedure; and
- a channel assignment message. The type of channel assigned may depend on the number of users in the cell who
respond to the notification in the counting procedure.
If counting is not required, the notification and channel assignment information may be transmitted in a single
(PACKET) PAGING REQUEST message in the case of an MBMS broadcast service or an MBMS multicast service.
6.1.1.1a Pre-notification
The network may indicate the incoming notification of a given MBMS service and MBMS session by sending a pre-
notification of this MBMS service and MBMS session to MBMS mobile stations in packet idle mode.
A pre-notification may be sent in PAGING REQUEST TYPE 1 or 2 messages on CCCH, or if PCCCH is present, in
PACKET PAGING REQUEST message and identifies the TMGI as well as, if available, the MBMS Session Identity.
Upon reception of a pre-notification for an MBMS service and MBMS session, a mobile station in packet idle mode
shall enter non-DRX mode and monitor notifications as described in sub-clause 6.1.1.2 in the following cases:
- the MBMS service is a broadcast service and the mobile station is required to receive this service; or
- the MBMS service is a multicast service and the mobile station has joined this service.
6.1.1.2 Notification of session start
6.1.1.2.1 General
When the network is informed that an MBMS session is starting or an ongoing MBMS broadcast session has an updated
MBMS service area, the network notifies mobile stations in packet idle mode or MAC-Idle state, and may notify mobile
stations in packet transfer mode or MAC-Shared state, or mobile stations in dedicated mode or MAC-Dedicated state, or
mobile stations in dual transfer mode or MAC-DTM state. The mobile stations in packet idle mode or MAC-Idle state
are notified on the (P)PCH by the network. The mobile stations in packet transfer mode or MAC-Shared state and the
mobile stations in dual transfer mode or MAC-DTM state may be notified on the PACCH by the network using a
distribution message. The mobile stations in dedicated mode or MAC-Dedicated state may be notified on the main
DCCH by the network.
The network may optionally initiate, on a per-cell basis, a counting mechanism (i.e. to count up to an operator-defined
user threshold > 0) to ascertain the interest of users in each cell. This may be used in order to select the type of MBMS
radio bearer (i.e. characterized by an uplink feedback channel or not) to establish. If counting is activated in a cell,
mobile stations shall respond to the notification using the initial counting procedure, see sub-clause 6.1.1.3.
If counting is not activated, the network may allocate the MBMS bearer in a cell using the MBMS bearer establishment
procedure, see sub-clause 6.1.1.4.
6.1.1.2.2 Mobile stations in packet idle mode or MAC-Idle state
If the network controls cells in the MBMS service area of a starting MBMS session (or of an ongoing MBMS broadcast
session with an updated MBMS service area), the network initiates the MBMS notification procedure on each of these
cells. A notification is sent in PAGING REQUEST TYPE 1 or 2 messages on CCCH, or if PCCCH is present, in
PACKET PAGING REQUEST message and identifies the TMGI as well as, if available, the MBMS Session Identity.
A notification may include the uplink resource description for a PRACH dedicated to MBMS (MPRACH). If a PRACH
is allocated in the cell, and no MPRACH Control Parameters are included in the notification message, the PRACH
Control Parameters shall be used for the MPRACH. If the network wishes to allocate an MPRACH and no PRACH is
allocated in the cell, the MBMS Notification message shall include the MPRACH Control Parameters. If present,
MPRACH Control Parameters take precedence over PRACH Control Parameters.
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If a mobile station has not joined the MBMS multicast service identified by the TMGI or has already received the
MBMS session identified by the TMGI and MBMS Session Identity combination contained in the (PACKET) PAGING
REQUEST message, the mobile station shall discard the message.
If the mobile station has not previously received the MBMS session identified by the TMGI and MBMS Session
Identity (if available) combination contained in the (PACKET) PAGING REQUEST message and the message includes
an indication that 'counting shall be used', then the mobile station shall initiate the initial counting procedure, see sub-
clause 6.1.1.3, otherwise if such an indication is not included then the mobile station shall continue with the MBMS
bearer establishment procedure, see sub-clause 6.1.1.4.
6.1.1.2.3 Mobile stations in packet transfer mode or MAC-Shared state and mobile stations
in dual transfer mode or MAC-DTM state
If the network controls cells in the MBMS service area of a starting MBMS session (or of an ongoing MBMS broadcast
session with an updated MBMS service area), the network may pass a PACKET MBMS ANNOUNCEMENT message
to all MBMS capable mobile stations that have a PACCH. The PACKET MBMS ANNOUNCEMENT message
includes the TMGI and, if available, the MBMS Session Identity of an MBMS session and may optionally include a
parameter that dictates whether there is maximum reaction time for the mobile station or the MBMS session
(remaining) duration, the uplink resource description for a PRACH dedicated to MBMS (MPRACH) possibly with
control parameters, or the channel assignment information for the MBMS session.
If the mobile station has not previously joined the MBMS multicast service identified by the TMGI or the mobile
station has already received the MBMS session identified by the TMGI and the MBMS Session Identity combination
contained in the PACKET MBMS ANNOUNCEMENT message, the mobile station discards the message. If the mobile
station has joined the MBMS multicast service identified by the TMGI contained in the PACKET MBMS
ANNOUNCEMENT message and has not received the session, optionally identified by the MBMS Session Identity,
then the mobile station stores the MBMS information contained in the PACKET MBMS ANNOUNCEMENT message,
initialises timer T3222 (see 3GPP TS 44.060) if indicated to do so and the session duration timer for this MBMS session
if the MBMS session (remaining) duration is included in the PACKET MBMS ANNOUNCEMENT message, and
passes the received TMGI, and the MBMS Session Identity if available, to the upper layers. If timer T3222 expires the
stored MBMS information associated with the timer is deleted.
If the mobile station returns to packet idle mode or MAC-Idle state when MBMS information is stored, then:
- if the channel assignment information for the MBMS session was not included in the PACKET MBMS
ANNOUNCEMENT message, the mobile station initiates the initial counting procedure using the stored MBMS
information, (see sub-clause 6.1.1.3), once the Transfer non-DRX mode period has elapsed;
- if the channel assignment information for the MBMS session was included in the PACKET MBMS
ANNOUNCEMENT message, the mobile station starts listening to the MBMS p-t-m radio bearer.
6.1.1.2.4 Mobile stations in dedicated mode or MAC-Dedicated state
If the network controls cells in the MBMS service area of a starting MBMS session (or of an ongoing MBMS broadcast
session with an updated MBMS service area), the network may pass an MBMS ANNOUNCEMENT message to all
mobile stations that have previously requested to be notified on the main DCCH. The MBMS ANNOUNCEMENT
message includes the TMGI and, if available, the MBMS Session Identity of an MBMS session and may optionally
include a parameter that dictates whether there is maximum reaction time for the mobile station or the MBMS session
(remaining) duration, the uplink resource description for a PRACH dedicated to MBMS (MPRACH) possibly with
control parameters, or the channel assignment information for the MBMS session.
If the mobile station has not previously joined the MBMS multicast service identified by the TMGI or the mobile
station has already received the MBMS session identified by the TMGI and the MBMS Session Identity combination
contained in the MBMS ANNOUNCEMENT message, the mobile station discards the message. If the mobile station
has joined the MBMS Service identified by the TMGI and has not received the session, optionally identified by the
MBMS Session Identity, then the mobile station stores the MBMS information contained in the MBMS
ANNOUNCEMENT message, initialises timer T3222 (see 3GPP TS 44.060) if indicated to do so and the session
duration timer for this MBMS session if the MBMS session (remaining) duration is included in the MBMS
ANNOUNCEMENT message, and passes the received TMGI, and the MBMS Session Identity if available, to the upper
layers. If timer T3222 expires the stored MBMS information associated with the timer is deleted.
If the mobile station returns to packet idle mode or MAC-Idle state when MBMS information is stored, then:
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- if the channel assignment information for the MBMS session was not included in the MBMS
ANNOUNCEMENT message, the mobile station initiates the initial counting procedure using the stored
MBMS information, see sub-clause 6.1.1.3;
- if the channel assignment information for the MBMS session was included in the MBMS ANNOUNCEMENT
message, the mobile station starts listening to the MBMS p-t-m radio bearer.
6.1.1.3 Initial counting procedure
The mechanism in the requirements 11 and 12 in A.1.1 implies that an MBMS channel should not be established if no
interested users are in the cell at the time of the notification of the MBMS session. The network using such a
mechanism would therefore wait for at least one response from an MBMS user in each cell before assigning the MBMS
bearer. The initial counting procedure can also be used to count the number of mobile stations when starting a broadcast
session.
If the notification message or the (PACKET) MBMS ANNOUNCEMENT message contains the uplink resource
description for an MPRACH, packet access for counting is initiated by the mobile station by sending on such MPRACH
a PACKET CHANNEL REQUEST message with access cause "Single Block MBMS Access" requesting a single
uplink block. The mobile station acts on any response sent by the network to that mobile station.
If the notification message or the (PACKET) MBMS ANNOUNCEMENT message does not contain any uplink
resource description for an MPRACH, packet access for counting is initiated by the mobile station by sending a
(PACKET) CHANNEL REQUEST message on the common (P)RACH, with access cause "Single Block MBMS
Access" requesting a single uplink block.
Upon reception by the network of a (PACKET) CHANNEL REQUEST message with access cause "Single Block
MBMS Access", the network sends an IMMEDIATE ASSIGNMENT message on CCCH (or a PACKET UPLINK
ASSIGNMENT message on PAGCH) allocating one uplink block to the mobile station.
Upon reception by the mobile station of an IMMEDIATE ASSIGNMENT (respectively PACKET UPLINK
ASSIGNMENT) message corresponding to one of its (PACKET) CHANNEL REQUEST messages and allocating one
uplink radio block for MBMS access, the mobile station sends in this radio block an MBMS SERVICE REQUEST
message on PACCH to the network including its TLLI, the TMGI and, if available, the MBMS Session Identity of the
session, and enters non-DRX mode. In case the MBMS SERVICE REQUEST message is not correctly received on the
network side, the network may repeat the IMMEDIATE ASSIGNMENT message on CCCH (or PACKET UPLINK
ASSIGNMENT message on PAGCH), allowing the mobile station to re-send the MBMS SERVICE REQUEST
message. The reception by the network of the MBMS SERVICE REQUEST message from a number of mobile stations
allows the network to estimate in a given cell the number of mobile stations interested in a given session.

BSC
MS
(P)PCH
(PACKET) PAGING REQUEST (Optional pre-notification)
- TMGI
- MBMS Session Identity, if available
(PACKET) PAGING REQUEST (P)PCH
- TMGI
- MBMS Session Identity, if available
- Do no perform counting
- No MBMS PTM channel defined
(P)CCCH
MBMS ASSIGNMENT
FIGURE 6.1.1.3.a: No counting and no PTM Bearer defined

ETSI
3GPP TS 43.246 version 13.0.0 Release 13 13 ETSI TS 143 246 V13.0.0 (2016-01)

BSC
MS
(PACKET) PAGING REQUEST (Optional pre-notification) (P)PCH
- TMGI
- MBMS Session Identity, if available
(PACKET) PAGING REQUEST (P)PCH
- TMGI
- MBMS Session Identity, if available
- Perform counting
- No MBMS PTM channel assigned
- Opt. MPRACH Channel
(P)RACH or
(PACKET) CHANNEL REQUEST
MPRACH
PAGCH/ CCCH
PACKET UPLINK ASSIGNMENT/ IMMEDIATE ASSIGNMENT
- Packet Control Parameters
- Frequency Parameters
- TBF Starting Time
- Timing Advance
- Packet Request Reference
PACCH
MBMS SERVICE REQUEST
(P)CCCH
MBMS ASSIGNMENT
FIGURE 6.1.1.3.b: Counting used

BSC
MS
(P)PCH
(PACKET) PAGING REQUEST (Optional pre-notification)
- TMGI
- MBMS Session Identity, if available
(PACKET) PAGING REQUEST
(P)PCH
- TMGI
- MBMS Session Identity, if available
- Do not perform counting
- MBMS PTM channel description
RLC DATA PDTCH
FIGURE 6.1.1.3.c: PTM Bearer established
This estimate may be used by the network to establish a point-to-multipoint channel for a given session, possibly
characterized by an uplink feedback channel, or to notify the mobile stations that no point-to-multipoint channel will be
established.
In case an uplink feedback channel is established, to receive MBMS DOWNLINK ACK/NACK messages from the
mobile stations addressing of mobile stations is required. This procedure is described in sub-clause 6.1.1.5. The network
may address (i.e. distribute MS_ID identifiers to) only a subset of the counted mobile stations. In this case, mobile
stations without an allocated MS_ID shall only listen to the MBMS p-t-m radio bearer and will not send any feedback.
ETSI
3GPP TS 43.246 version 13.0.0 Release 13 14 ETSI TS 143 246 V13.0.0 (2016-01)
6.1.1.4 MBMS bearer establishment
The network may allocate the MBMS bearer by including the bearer description and the MBMS session duration in the
notification message. An MBMS bearer allocated via the notification message will initially operate without ARQ at the
RLC/MAC layer (see sub-clause 6.3.1.1).
The network may send the MBMS ASSIGNMENT message as a distribution message on PAGCH or, if PCCCH is not
present in the cell, the IMMEDIATE ASSIGNMENT message including the Multiple Blocks Packet Downlink
Assignment construction on AGCH followed by the MBMS ASSIGNMENT message sent on the PDCH specified by
the Packet Channel Description IE in the IMMEDIATE ASSIGNMENT message (see 3GPP TS 44.060 and 3GPP TS
44.018) to all interested mobile stations in packet idle mode.
The network either assigns a point-to-multipoint bearer for the transmission of the MBMS session in a cell, or notifies
the mobile stations that a p-t-m bearer will not be established in the cell. The decision of whether to allocate resources
in a cell is implementation dependent.
The MBMS ASSIGNMENT message may be sent as a non-distribution message to a specific mobile station that
performs an access.
The MBMS ASSIGNMENT message includes the TMGI, the Session Id when available, the MBMS session duration,
the MBMS_BEARER_ID, the MBMS In-band Signalling Indicator (see sub-clause 6.6) and
...