Method and apparatus for handling discontinuous reception (drx) timer for data reception of unicast and multicast in a wireless communication system

Abstract

In an example, a User Equipment (UE) receives and/or detects a transmission of data from a network. The transmission of the data is addressed to a Group Radio Network Temporary Identifier (G-RNTI) for a Hybrid Automatic Repeat Request (HARQ) process. In response to receiving and/or detecting the transmission of the data, the UE (i) starts a first HARQ Round Trip Time (RTT) timer associated with the G-RNTI for the HARQ process, and (ii) starts a second HARQ RTT timer associated with a Cell Radio Network Temporary Identifier (C-RNTI) for the HARQ process. The UE starts a multicast retransmission timer for the HARQ process in response to expiry of the first HARQ RTT timer. The UE starts a unicast retransmission timer for the HARQ process in response to expiry of the second HARQ RTT timer. The UE receives and/or detects a first retransmission of the DL data addressed to the G-RNTI for the HARQ process. In response to receiving and/or detecting the first retransmission of the data, the UE (i) stops the multicast retransmission timer, and (ii) stops the unicast retransmission timer.

1 . A method of a User Equipment (UE), the method comprising:
 at least one of receiving or detecting a first Physical Downlink Control Channel (PDCCH) of a transmission of data from a network, wherein the transmission of the data is addressed to a Group Radio Network Temporary Identifier (G-RNTI) for a Hybrid Automatic Repeat Request (HARQ) process; and   in response to at least one of receiving or detecting the first PDCCH of the transmission of the data:
 starting a multicast HARQ Round Trip Time (RTT) timer for the same HARQ process; and 
 starting a unicast HARQ RTT timer for the same HARQ process. 
   
     
     
         2 . The method of  claim 1 , comprising:
 in response to expiry of the multicast HARQ RTT timer, starting a multicast retransmission timer for the same HARQ process;   in response to expiry of the unicast HARQ RTT timer, starting a unicast retransmission timer for the same HARQ process;   at least one of receiving or detecting a second PDCCH of a first retransmission of the data addressed to the G-RNTI for the same HARQ process; and   in response to at least one of receiving or detecting the second PDCCH of the first retransmission of the data for the same HARQ process:
 stopping the multicast retransmission timer; and 
 stopping the unicast retransmission timer. 
   
     
     
         3 . The method of  claim 2 , comprising:
 at least one of receiving or detecting a third PDCCH of a second retransmission of the data addressed to a Cell Radio Network Temporary Identifier (C-RNTI) for the same HARQ process; and   in response to at least one of receiving or detecting the third PDCCH of the second retransmission of the data:
 stopping the multicast retransmission timer; and 
 stopping the unicast retransmission timer. 
   
     
     
         4 . The method of  claim 2 , comprising:
 monitoring the second PDCCH of the first retransmission of the data when at least one of the multicast retransmission timer is running or the unicast retransmission timer is running.   
     
     
         5 . The method of  claim 1 , wherein:
 the G-RNTI is used by the UE for receiving services from the network.   
     
     
         6 . The method of  claim 5 , wherein:
 the G-RNTI is associated with a group of UEs, comprising the UE, that receive services from the network.   
     
     
         7 . The method of  claim 1 , comprising:
 transmitting, to the network, Negative Acknowledgment (NACK) information for the same HARQ process if the data is not successfully decoded.   
     
     
         8 . The method of  claim 1 , wherein:
 the network comprises a Next Generation NodeB (gNB).   
     
     
         9 . The method of  claim 1 , wherein:
 the data comprises at least one of a transport block (TB) or a Medium Access Control Protocol Data Unit (MAC PDU).   
     
     
         10 . A method of a User Equipment (UE), the method comprising:
 at least one of receiving or detecting a first Physical Downlink Control Channel (PDCCH) of a transmission of data, associated with a Hybrid Automatic Repeat Request (HARQ) process, from a network; and   in response to at least one of receiving or detecting the first PDCCH of the transmission of the data, at least one of:
 starting a multicast HARQ Round Trip Time (RTT) timer for the same HARQ process if the transmission of the data is addressed to a Group Radio Network Temporary Identifier (G-RNTI); or 
 starting a unicast HARQ RTT timer for the same HARQ process if the transmission of the data is addressed to the G-RNTI or a Cell Radio Network Temporary Identifier (C-RNTI). 
   
     
     
         11 . The method of  claim 10 , comprising:
 in response to expiry of the multicast HARQ RTT timer, starting a multicast retransmission timer for the same HARQ process;   in response to expiry of the unicast HARQ RTT timer, starting a unicast retransmission timer for the same HARQ process;   at least one of receiving or detecting a second PDCCH of a first retransmission of the data addressed to the G-RNTI or the C-RNTI for the same HARQ process; and   in response to at least one of receiving or detecting the second PDCCH of the first retransmission of the data for the same HARQ process:
 stopping the multicast retransmission timer; and 
 stopping the unicast retransmission timer. 
   
     
     
         12 . The method of  claim 11 , comprising:
 monitoring the second PDCCH of the first retransmission of the data when at least one of the multicast retransmission timer is running or the unicast retransmission timer is running.   
     
     
         13 . The method of  claim 10 , wherein:
 the G-RNTI is used by the UE for receiving services from the network.   
     
     
         14 . The method of  claim 10 , comprising:
 transmitting, to the network, Negative Acknowledgment (NACK) information for the same HARQ process if the data is not successfully decoded.   
     
     
         15 . The method of  claim 10 , wherein:
 the network comprises a Next Generation NodeB (gNB).   
     
     
         16 . The method of  claim 10 , wherein:
 the data comprises at least one of a transport block (TB) or a Medium Access Control Protocol Data Unit (MAC PDU).   
     
     
         17 . A User Equipment (UE), comprising:
 a control circuit;   a processor installed in the control circuit; and   a memory installed in the control circuit and operatively coupled to the processor, wherein the processor is configured to execute a program code stored in the memory to perform operations, the operations comprising:
 at least one of receiving or detecting a first Physical Downlink Control Channel (PDCCH) of a transmission of data from a network, wherein the transmission of the data is addressed to a Group Radio Network Temporary Identifier (G-RNTI) for a Hybrid Automatic Repeat Request (HARQ) process; and 
 in response to at least one of receiving or detecting the first PDCCH of the transmission of the data:
 starting a multicast HARQ Round Trip Time (RTT) timer for the same HARQ process; and 
 starting a unicast HARQ RTT timer for the same HARQ process. 
 
   
     
     
         18 . The UE of  claim 17 , the operations comprising:
 in response to expiry of the multicast HARQ RTT timer, starting a multicast retransmission timer for the same HARQ process;   in response to expiry of the unicast HARQ RTT timer, starting a unicast retransmission timer for the same HARQ process;   at least one of receiving or detecting a second PDCCH of a first retransmission of the data addressed to a Cell Radio Network Temporary Identifier (C-RNTI) for the same HARQ process; and   in response to at least one of receiving or detecting the second PDCCH of the first retransmission of the data for the same HARQ process:
 stopping the multicast retransmission timer; and 
 stopping the unicast retransmission timer. 
   
     
     
         19 . The UE of  claim 18 , the operations comprising:
 monitoring the second PDCCH of the first retransmission of the data when at least one of the multicast retransmission timer is running or the unicast retransmission timer is running.   
     
     
         20 . A method of a User Equipment (UE), the method comprising:
 in response to expiry of a multicast Hybrid Automatic Repeat Request (HARQ) Round Trip Time (RTT) timer, starting a multicast retransmission timer for a HARQ process;   in response to expiry of a unicast HARQ RTT timer, starting a unicast retransmission timer for the same HARQ process;   at least one of receiving or detecting a Physical Downlink Control Channel (PDCCH) of a first retransmission of data addressed to a Group Radio Network Temporary Identifier (G-RNTI) or a Cell Radio Network Temporary Identifier (C-RNTI) for the same HARQ process; and   in response to at least one of receiving or detecting the PDCCH of the first retransmission of the data for the same HARQ process:
 stopping the multicast retransmission timer; and 
 stopping the unicast retransmission timer.