Methods and systems of HARQ retransmission for NR MBS services
The disclosure relates to a 5G or 6G communication system for supporting a higher data transmission rate. Methods and systems of HARQ retransmission for NR MBS services. Embodiments herein disclose methods and systems of HARQ retransmission for NR MBS services. Embodiments herein disclose a DRX approach and HARQ transmission and retransmission for MBS packets in order to support power efficient and reliable delivery of 5G MBS services. Embodiments herein disclose a DRX approach and HARQ transmission and retransmission for MBS packets, which work for the PTM and PTP based delivery framework for NR MBS.
1 . A method performed by a user equipment (UE) in a wireless communication system, the method comprising:
receiving, from a base station, a medium access control (MAC) protocol data unit (PDU) in a configured downlink multicast assignment; and
when a hybrid automatic repeat request (HARQ) feedback is enabled,
starting a first HARQ round trip time (RTT) timer associated with a point to multipoint (PTM) for a corresponding first HARQ process and starting a second HARQ RTT timer for the corresponding first HARQ process based on a configured scheduling-radio network temporary identifier (CS-RNTI) being configured,
wherein the first HARQ RTT timer and the second HARQ RTT timer start in a first symbol after an end of a corresponding transmission carrying a first HARQ feedback.
2 . The method of claim 1 , further comprising:
when the HARQ feedback is disabled, starting the first HARQ RTT timer associated with the PTM for a corresponding second HARQ process in a first symbol after an end of the corresponding transmission carrying a second HARQ feedback that would be performed if the HARQ feedback were enabled.
3 . The method of claim 1 , further comprising:
when the first HARQ RTT timer associated with the PTM expires and data for a corresponding HARQ process was not successfully decoded, starting a discontinuous reception (DRX) retransmission timer associated with the PTM for the corresponding HARQ process in a first symbol after an expiry of the first HARQ RTT timer associated with the PTM.
4 . The method of claim 1 , wherein a multicast DRX is configured for a group-radio network temporary identifier (G-RNTI) or a group-configured scheduling-radio network temporary identifier (G-CS-RNTI).
5 . The method of claim 1 , wherein a multicast DRX is configured for a multicast in a radio resource control (RRC) inactive state.
6 . A method performed by a base station in a wireless communication system, the method comprising:
transmitting, to a user equipment (UE), a medium access control (MAC) protocol data unit (PDU) in a configured downlink multicast assignment,
wherein when a hybrid automatic repeat request (HARQ) feedback is enabled, a first HARQ round trip time (RTT) timer associated with a point to multipoint (PTM) for a corresponding first HARQ process starts and a second HARQ RTT timer for the corresponding first HARQ process starts based on a configured scheduling-radio network temporary identifier (CS-RNTI) being configured, and
wherein the first HARQ RTT timer and the second HARQ RTT timer start in a first symbol after an end of a corresponding transmission carrying a first HARQ feedback.
7 . The method of claim 6 , when the HARQ feedback is disabled, the first HARQ RTT timer associated with the PTM for a corresponding second HARQ process starts in a first symbol after an end of a corresponding transmission carrying a second HARQ feedback that would be performed if the HARQ feedback were enabled.
8 . The method of claim 6 , when the first HARQ RTT timer associated with the PTM expires and data for a corresponding HARQ process was not successfully decoded, a discontinuous reception (DRX) retransmission timer associated with the PTM for the corresponding HARQ process starts in a first symbol after an expiry of the first HARQ RTT timer associated with the PTM.
9 . The method of claim 6 , wherein a multicast DRX is configured for a group-radio network temporary identifier (G-RNTI) or a group-configured scheduling-radio network temporary identifier (G-CS-RNTI).
10 . The method of claim 6 , wherein a multicast DRX is configured for a multicast in a radio resource control (RRC) inactive state.
11 . A user equipment (UE) in a wireless communication system, the UE comprising:
a transceiver, and a controller coupled with the transceiver, and configured to:
receive, from a base station, a medium access control (MAC) protocol data unit (PDU) in a configured downlink multicast assignment, and
when a hybrid automatic repeat request (HARQ) feedback is enabled, start a first HARQ round trip time (RTT) timer associated with a point to multipoint (PTM) for a corresponding first HARQ process and start a second HARQ RTT timer for the corresponding first HARQ process based on a configured scheduling-radio network temporary identifier (CS-RNTI) being configured,
wherein the first HARQ RTT timer and the second HARQ RTT timer start in a first symbol after an end of a corresponding transmission carrying a first HARQ feedback.
12 . The UE of claim 11 , wherein the controller is further configured to:
when the HARQ feedback is disabled, start the first HARQ RTT timer associated with the PTM for a corresponding second HARQ process in a first symbol after an end of a corresponding transmission carrying a second HARQ feedback that would be performed if the HARQ feedback were enabled.
13 . The UE of claim 11 , wherein the controller is further configured to:
when the first HARQ RTT timer associated with the PTM expires and data for a corresponding HARQ process was not successfully decoded, start a discontinuous reception (DRX) retransmission timer associated with the PTM for the corresponding HARQ process in a first symbol after an expiry of the first HARQ RTT timer associated with the PTM.
14 . The UE of claim 11 , wherein a multicast DRX is configured for a group-radio network temporary identifier (G-RNTI) or a group-configured scheduling-radio network temporary identifier (G-CS-RNTI).
15 . The UE of claim 11 , wherein a multicast DRX is configured for a multicast in a radio resource control (RRC) inactive state.
16 . A base station in a wireless communication system, the base station comprising:
a transceiver, and
a controller coupled with the transceiver, and configured to:
transmit, to a user equipment (UE), a medium access control (MAC) protocol data unit (PDU) in a configured downlink multicast assignment,
wherein when a hybrid automatic repeat request (HARQ) feedback is enabled, a first HARQ round trip time (RTT) timer associated with a point to multipoint (PTM) for a corresponding first HARQ process starts and a second HARQ RTT timer for the corresponding first HARQ process starts based on a configured scheduling-radio network temporary identifier (CS-RNTI) being configured, and
wherein the first HARQ RTT timer and the second HARQ RTT timer start in a first symbol after an end of a corresponding transmission carrying a first HARQ feedback.
17 . The base station of claim 16 , when the HARQ feedback is disabled, the first HARQ RTT timer associated with the PTM for a corresponding second HARQ process starts in a first symbol after an end of a corresponding transmission carrying a second HARQ feedback that would be performed if the HARQ feedback were enabled.
18 . The base station of claim 16 , when the first HARQ RTT timer associated with the PTM expires and data for a corresponding HARQ process was not successfully decoded, a discontinuous reception (DRX) retransmission timer associated with the PTM for the corresponding HARQ process starts in a first symbol after an expiry of the first HARQ RTT timer associated with the PTM.
19 . The base station of claim 16 , wherein a multicast DRX is configured for a group-radio network temporary identifier (G-RNTI) or a group-configured scheduling-radio network temporary identifier (G-CS-RNTI).
20 . The base station of claim 16 , wherein a multicast DRX is configured for a multicast in a radio resource control (RRC) inactive state.