The following RAN requirements have been identified :
- MBMS data transfer shall be downlink only.
- QoS attributes shall be the same for MBMS Multicast and Broadcast modes.
- During MBMS data transmission it shall be possible to receive paging messages, which also should contain some additional information, such as CLI.
- Simultaneous reception of MBMS and non-MBMS services shall depend upon UE capabilities.
- Simultaneous reception of more than one MBMS services shall depend upon UE capabilities.
- A notification procedure shall be used to indicate the start of MBMS data transmission. This procedure shall contain MBMS RB information.
- A mechanism to enable the Network to move MBMS subscribers between cells is required.
- MBMS UE multicast activation (Joining) shall be transparent to UTRAN.
- A mechanism is required that enables the non-transmission of MBMS multicast mode in a cell which does not contain any MBMS UEs joined to the multicast group.
- Reception of MBMS shall not be guaranteed at RAN level. MBMS does not support individual retransmissions at the radio link layer, nor does it support retransmissions based on feedback from individual subscribers at the radio level. This does not preclude the periodic repetitions of the MBMS content based on operator or content provider scheduling or retransmissions based on feedback at the application level.
- MBMS shall not prevent the capability for SRNS/SBSS relocation.
- A mechanism to provide UTRAN the received QoS per UE is not required as part of MBMS.
- UE controlled "service based" cell selection/reselection shall not be permitted.
- Handover and SGSN relocation shall not be affected by an active MBMS session.
- In the case of UTRAN only, guaranteed 'QoS' linked to a certain initial downlink power setting is not required; however, the purpose and possibility of some reporting mechanism could be identified to measure the delivered QoS.
- MBMS Multicast mode transmissions should use dedicated resources (p-t-p) or common resources (p-t-m). The selection of the connection type (p-t-p or p-t-m) is operator dependent, typically based on downlink radio resource environment such as radio resource efficiency. A "threshold" related to the number of users may be utilised, resulting in the need for a mechanism to identify the number of subscribers in a given "area".
- MBMS solutions to be adopted should minimise the impact on the RAN physical layer and maximise reuse of existing physical layer and other RAN functionality.
- MBMS charging should be transparent to the RAN.
- MBMS should allow for low UE power consumption.
- Header compression should be used.
- MBMS should not prevent support for SGSN in pool.
- Data loss during cell change should be minimal.
The following MBMS Notification Requirements have been identified:
- MBMS notification shall be transmitted within the MBMS service area.
- MBMS notification shall be sent so it could be received by all UEs with an activated MBMS service, regardless of their RRC state or the lack of an RRC connection.
- MBMS notification should maximise the reuse of existing channels.
- MBMS notification should allow terminals to minimise their power consumption, meaning that UEs with an activated MBMS service should not listen permanently, but at regular intervals to MBMS notification.
- Reception of MBMS notification cannot be guaranteed.
- UEs may receive MBMS notification and simultaneously monitor other occasions, e.g. UE dedicated paging and CBS messages. The avoidance of collisions cannot be guaranteed. If collisions occur, the UE dedicated Paging has higher priority (UE requirement).