METHOD OF MULTIMEDIA BROADCAST/MULTICAST SERVICE (MBMS) DELIVERY MODE SWITCH
Delivery mode switching between unicast and multicast/broadcast is described. A WTRU may move from a RAN node that supports multimedia broadcast/multicast service (MBMS) session to one that does not support MBMS session, or vice versa. In order to avoid duplicated packet transmission, the unicast delivery mode may be deactivated when the WTRU decides to use multi-cast/broadcast session. When the multicast/broadcast session is not available, the WTRU may re-activate the unicast delivery mode for MBMS. For example, the PDU session for unicast delivery mode deactivation may be released and the PDU session for unicast delivery mode reactivation may be re-established. Such activity may necessitate additional signaling between WTRU and the network for PDU session establishment/release and all other services running in the PDU session may be interrupted.
1 . A method for suspending reception of a multimedia broadcast multicast service (MBMS), the method comprising:
receiving a MBMS data stream in a unicast delivery mode;
transmitting, based on a determination to deactivate the unicast delivery mode, a session management non-access stratum (NAS) message to a session management function (SMF), wherein the SMF NAS message incudes a suspend indication; and
receiving the MBMS data stream in multicast delivery mode.
2 . The method of claim 1 , wherein the method is performed by a wireless transmit/receive unit (WTRU).
3 . The method of claim 1 , further comprising receiving a radio access network (RAN) resource release message in response to transmitting the session management NAS message.
4 . The method of claim 1 , further comprising receiving a protocol data unit (PDU) session modification command from the SMF.
5 . The method of claim 1 , further comprising transmitting multimedia broadcast/multicast service (MBMS) information with the NAS message to the SMF.
6 . A method for suspending reception of a multimedia broadcast multicast service (MBMS), the method comprising:
deciding to suspend a protocol data unit (PDU) session;
transmitting a session modification request to a user plan function (UPF);
receiving a modification response from the UPF; and
notifying the UPF to discard a MBMS packet during the PDU session.
7 . The method of claim 6 , wherein the method is performed by a session management function (SMF).
8 . The method of claim 6 , further comprising deciding to suspend the PDU session based on a PDU session modification request from a wireless transmit/receive unit (WTRU).
9 . The method of claim 6 , further comprising deciding to suspend the PDU session based on a location of the WTRU.
10 . A wireless transmit/receive unit (WTRU) comprising:
a transceiver; and
a processor;
wherein the transceiver and processor are configured to:
receive a multimedia broadcast multicast service (MBMS) data stream in a unicast delivery mode;
transmit, based on a determination to deactivate the unicast delivery mode, a session management non-access stratum (NAS) message to a session management function (SMF), wherein the SMF NAS message includes a suspend indication; and
receive the MBMS data stream in multicast delivery mode.
11 . The WTRU of claim 10 , wherein the transceiver and processor are further configured to receive a radio access network (RAN) resource release message in response to the session management NAS message.
12 . The WTRU of claim 10 , wherein the transceiver and processor are further configured to receive a protocol data unit (PDU) session modification command from the SMF.
13 . The WTRU of claim 10 , wherein the transceiver and processor are further configured to transmit multimedia broadcast/multicast service (MBMS) information with the NAS message to the SMF.
14 . The method of claim 6 , wherein the session modification request is an N4 session modification request.
15 . The method of claim 6 , wherein the modification response is an N4 modification response.