Method and apparatus for handling L2 entity in channel change for relaying in wireless communication system
A method and apparatus for handling a L2 entity in a wireless communication system is provided. A user equipment (UE) receives data via a first logical channel, changes a type of a logical channel from the first logical channel to a second logical channel, determines whether to re-establish a L2 entity for the first logical channel, and receives the data via the second logical channel.
1. A method for handling, by a user equipment (UE), a L2 entity in a wireless communication system, the method comprising:
receiving, from an old relay UE, data via a first sidelink traffic channel (STCH);
performing a relay UE reselection from the old relay UE to a new relay UE for the data;
when the old relay UE and the new relay UE inform different multicast-broadcast single-frequency network (MBSFN) area identifiers (IDs) or different multimedia broadcast multicast services (MBMS) channel IDs:
re-establishing a L2 entity; and
receiving the data via a second STCH with the re-established L2 entity; and
when the old relay UE and the new relay UE inform same MBSFN area IDs or same MBMS channel IDs:
maintaining the L2 entity; and
receiving the data via the second STCH with the maintained L2 entity,
wherein the L2 entity includes a radio link control (RLC) entity and a packet data convergence protocol (PDCP) entity.
2. The method of claim 1 , wherein it is determined to re-establish the L2 entity for the first logical channel when the new relay UE informs re-establishment to the UE.
3. A user equipment (UE) in a wireless communication system, the UE comprising:
a memory;
a transceiver; and
a processor coupled to the memory and the transceiver,
wherein the processor is configured to:
control the transceiver to receive data via a first sidelink traffic channel (STCH) from an old relay UE,
perform a relay UE reselection from the old relay UE to a new relay UE for the data,
when the old relay UE and the new relay UE inform different multicast-broadcast single-frequency network (MBSFN) area identifiers (IDs) or different multimedia broadcast multicast services (MBMS) channel IDs:
re-establish a L2 entity; and
receive the data via a second STCH with the re-established L2 entity, and
when the old relay UE and the new relay UE inform same MBSFN area IDs or same MBMS channel IDs:
maintain the L2 entity; and
receive the data via the second STCH with the maintained L2 entity,
wherein the L2 entity includes a radio link control (RLC) entity and a packet data convergence protocol (PDCP) entity.