Method and apparatus for performing contention resolution for contention based PUSCH transmission in wireless communication system
A method and apparatus for performing contention resolution for contention based physical uplink shared channel (CB-PUSCH) transmission in a wireless communication system is provided. A user equipment (UE) performs a first hybrid automatic repeat request (HARQ) transmission on a CB-PUSCH to a network, and determines whether contention on the CB-PUSCH is resolved. The CB-PUSCH is a channel for UL data allocated by a pre-configured UL grant which is shared by multiple UEs. If a UL grant includes an identity of the UE, it is determined that contention on the CB-PUSCH is resolved. The UE may perform a second HARQ transmission for the first HARQ transmission on a PUSCH to the network by using the UL grant.
1. A method performed by a user equipment (UE) in a wireless communication system, the method comprising:
performing a first hybrid automatic repeat request (HARQ) transmission, on a contention based physical uplink shared channel (CB-PUSCH), to a network;
receiving a UL grant on a physical downlink control channel (PDCCH) from the network,
wherein the UL grant includes an identity of the UE;
determining that contention on the CB-PUSCH is resolved based on the identity of the UE; and
performing a second HARQ transmission for the first HARQ transmission, on a non-contention PUSCH, to the network based on the UL grant,
wherein the CB-PUSCH is a channel for UL data allocated by a pre-configured UL grant which is shared by multiple UEs.
2. The method of claim 1 , further comprising receiving an acknowledgement/non-acknowledgement (ACK/NACK) of the second HARQ transmission on a physical HARQ indicator channel (PHICH) from the network.
3. The method of claim 2 , further comprising determining whether to perform a third HARQ transmission, for the second HARQ transmission, based on the received ACK/NACK.
4. The method of claim 1 , wherein the UL grant includes a HARQ process ID assigned by the network.
5. The method of claim 1 , wherein it is determined that contention on the CB-PUSCH is not resolved when the UE does not receive a UL grant on a PDCCH for HARQ retransmission or the UL grant does not include an identity of the UE.
6. The method of claim 5 , further comprising transmitting a scheduling request (SR) to the network via one of a random access, a dedicated scheduling request, or a contention based SR (CB-SR).
7. The method of claim 5 , further comprising retrying the first HARQ transmission on the CB-PUSCH to the network for a certain time period.
8. A user equipment (UE) in a wireless communication system, the UE comprising:
a memory;
a transceiver; and
a processor, operatively coupled to the memory and the transceiver,
wherein the processor is configured to:
perform a first hybrid automatic repeat request (HARQ) transmission, on a contention based physical uplink shared channel (CB-PUSCH), to a network,
control the transceiver to receive a UL grant on a physical downlink control channel (PDCCH) from the network,
wherein the UL grant includes an identity of the UE;
determine that contention on the CB-PUSCH is resolved based on the identity of the UE; and
perform a second HARQ transmission for the first HARQ transmission, on a non-contention PUSCH, to the network based on the UL grant,
wherein the CB-PUSCH is a channel for UL data allocated by a pre-configured UL grant which is shared by multiple UEs.
9. The UE of claim 8 , wherein it is determined that contention on the CB-PUSCH is not resolved when the UE does not receive a UL grant on a PDCCH for HARQ retransmission or the UL grant does not include an identity of the UE.