Multicast/broadcast service in mobile communication system
The present disclosure relates to a 5G communication system for supporting a higher data transmission rate than a 4G communication system such as LTE. The present disclosure provides a method of a terminal supporting a multicast/broadcast service (MBS) in a wireless communication system. The method includes the steps of: receiving, from a base station, a radio resource control (RRC) message indicating to switch from a multicast service (point-to-multicast (PTM)) to a unicast service (point-to-point (PTP)); and initializing at least one window parameter on the basis of received packet data convergence protocol (PDCP) data.
1 . A method of a terminal for supporting a multicast/broadcast service (MBS) by a user equipment (UE) in a wireless communication system, the method comprising:
receiving, from a source base station, a radio resource control (RRC) message for a handover including bearer configuration information for an MBS bearer, wherein the bearer configuration information includes a first indicator associated with a packet data convergence protocol (PDCP) reestablishment for the MBS bearer and a second indicator associated with a PDCP status report for the MBS bearer;
requesting, by an upper layer of the UE, a PDCP entity reestablishment for the MBS bearer based on the first indicator;
when the upper layer requests the PDCP entity reestablishment, triggering the PDCP status report by a PDCP entity of the UE; and
transmitting, to a target base station, the PDCP status report for the MBS bearer,
wherein the PDCP entity is associated with a radio link control (RLC) entity operating in an acknowledged mode (AM).
2 . A user equipment (UE) for supporting a multicast/broadcast service (MBS) in a wireless communication system, the UE comprising:
a transceiver; and
at least one processor coupled to the transceiver, the at least one processor configured to;
receive, from a source base station, a radio resource control (RRC) message for a handover including bearer configuration information for an MBS bearer, wherein the bearer configuration information includes a first indicator associated with a packet data convergence protocol (PDCP) reestablishment for the MBS bearer and a second indicator associated with a PDCP status report for the MBS bearer,
request, by an upper layer of the UE, a PDCP entity reestablishment for the MBS bearer based on the first indicator,
when the upper layer requests the PDCP entity reestablishment, trigger the PDCP status report by a PDCP entity of the UE, and
transmit, to a target base station, the PDCP status report for the MBS bearer,
wherein the PDCP entity is associated with a radio link control (RLC) entity operating in an acknowledged mode (AM).
3 . The method of claim 1 , wherein the source base station and a target base 16 , station support the MBS.
4 . The method of claim 1 , wherein the RLC entity operating in the AM is for a point-to-point (PTP) transmission.
5 . The method of claim 1 , further comprising:
when the upper layer requests a PDCP reestablishment, reestablishing the PDCP entity for the MBS bearer,
wherein reestablishing the PDCP entity comprises setting at least one variable of the PDCP entity to an initial value, the initial value is included in the RRC message.
6 . The UE of claim 2 , wherein the source base station and a target base station support the MBS.
7 . The UE of claim 2 , wherein the RLC entity operating in the AM is for a point-to-point (PTP) transmission.
8 . The UE of claim 2 , wherein the at least one processor is further configured to, in case that the upper layer requests a PDCP reestablishment, reestablish the PDCP entity for the MBS bearer, and
wherein for reestablishing the PDCP entity, the at least one processor is further configured to set at least one variable of the PDCP entity to an initial value, the initial value being included in the RRC message.
9 . A method for supporting a multicast/broadcast service (MBS) by a source base station in a wireless communication system, the method comprising:
transmitting, to a target base station, a handover request message including information on MBS service;
receiving, from the target base station, a handover request accept message including the information on MBS service; and
transmitting, to a user equipment (UE), a radio resource control (RRC) message for a handover including bearer configuration information for an MBS bearer, wherein the bearer configuration information includes a first indicator associated with a packet data convergence protocol (PDCP) reestablishment for the MBS bearer and a second indicator associated with a PDCP status report for the MBS bearer.
10 . The method of claim 9 , wherein the source base station and the target base station support the MBS.
11 . The method of claim 9 , further comprising:
forwarding downlink data to the target base station while performing the handover.
12 . The method of claim 9 , wherein a radio link control (RLC) entity operating in the AM is for a point-to-point (PTP) transmission.
13 . The method of claim 9 , wherein the RRC message includes an initial value for at least one variable of the PDCP entity.