Two-stage physical sidelink control channel (PSCCH) for sidelink communications

1. A method, comprising:

obtaining a sidelink control information (SCI) related configuration received from a base station or by a UE pre-configuration;

transmitting from a transmission user equipment (Tx UE) to a reception user equipment (Rx UE) data of a transport block with two-stage SCI including a 1st-stage SCI and a 2nd-stage SCI based on the SCI related configuration, wherein

the 1st-stage SCI carries information related to channel sensing, and is transmitted over a physical sidelink control channel (PSCCH) to the RX UE, and wherein the information related to channel sensing includes one of: priority information of the transport block; or information of time-frequency resource assignment for transmission of the transport block, and wherein the 1st-stage SCI has a predefined time-frequency location, and a same number of resource elements for unicast, groupcast, and broadcast,

at least one of the 2nd-stage SCI or the data is transmitted over a physical sidelink shared channel (PSSCH) to the RX UE; and

performing data transceiving with the Rx UE based on the 1 st -stage SCI and the 2 nd -stage SCI.

2. The method of claim 1 , wherein the 1st-stage SCI has a same payload size for unicast, groupcast, and broadcast.

3. The method of claim 1 , wherein the 1st-stage SCI indicates time-frequency location of the 2nd-stage SCI.

4. The method of claim 1 , wherein the 1st-stage SCI indicates a number of resource elements carrying the 2nd-stage SCI, or an aggregation level of the 2nd-stage SCI.

5. The method of claim 1 , wherein the 1st-stage SCI indicates at least one of a modulation and coding scheme (MCS) of the PSSCH, or the 1st-stage SCI include a demodulation reference signal (DMRS) pattern associated with the PSSCH.

6. The method of claim 1 , wherein the 1st-stage SCI includes antenna ports information including at least one of: a number of antenna ports, one or more antenna ports.

7. The method of claim 1 , wherein the 2nd-stage SCI includes at least one of a source identifier (ID) of the Tx UE or a destination ID of the Rx UE.

8. The method of claim 7 , wherein the source ID or the destination ID is scrambled in a cyclic redundancy check (CRC) of the 2nd-stage SCI.

9. The method of claim 1 , wherein the 1st-stage SCI includes a format indicator to indicate whether a single SCI or a two-stage SCI is used for transmitting the transport block.

10. The method of claim 1 , wherein the 1st-stage SCI includes a radio network temporary identifier (RNTI) or a physical layer ID (L1-ID) to indicate whether a single SCI or a two-stage SCI is used for transmitting the transport block.

11. The method of claim 1 , wherein the 1st-stage SCI includes information to indicate whether a single SCI is used for broadcast communication of the transport block, or a two-stage SCI is used for unicast or groupcast communication of the transport block.

12. An apparatus, comprising circuitry configured to:

obtain a sidelink control information (SCI) related configuration received from a base station or by a UE pre-configuration;

transmit from the apparatus to a reception user equipment (Rx UE) data of a transport block with two-stage SCI including a 1st-stage SCI and a 2nd-stage SCI based on the SCI related configuration, wherein

the 1st-stage SCI carries information related to channel sensing, and is transmitted over a physical sidelink control channel (PSCCH) to the RX UE, and wherein the information related to channel sensing includes one of: priority information of the transport block; or information of time-frequency resource assignment for transmission of the transport block, and wherein the 1st-stage SCI has a predefined time-frequency location, and a same number of resource elements for unicast, groupcast, and broadcast,

at least one of the 2nd-stage SCI or the data is transmitted over a physical sidelink shared channel (PSSCH) to the RX UE;

and

perform data transceiving with the Rx UE based on the 1 st -stage SCI and the 2 nd -stage SCI.

13. The apparatus of claim 12 , wherein the 1st-stage SCI has a same payload size for unicast, groupcast, and broadcast.

14. The apparatus of claim 12 , wherein the 1st-stage SCI indicates time-frequency location of the 2nd-stage SCI.

15. The apparatus of claim 12 , wherein the 1st-stage SCI indicates a number of resource elements carrying the 2nd-stage SCI, or an aggregation level of the 2nd-stage SCI.

16. A non-transitory computer-readable medium storing instructions that, when executed by a processor, cause the processor to perform a method, the method comprising:

a sidelink control information (SCI) related configuration received from a base station or by a UE pre-configuration;

transmitting from a transmission user equipment (Tx UE) to a reception user equipment (Rx UE) data of a transport block with two-stage SCI including a 1st-stage SCI and a 2nd-stage SCI based on the SCI related configuration, wherein

the 1st-stage SCI carries information related to channel sensing, and is transmitted over a physical sidelink control channel (PSCCH) to the RX UE, and wherein the information related to channel sensing includes one of: priority information of the transport block; or information of time-frequency resource assignment for transmission of the transport block, and wherein the 1st-stage SCI has a predefined time-frequency location, and a same number of resource elements for unicast, groupcast, and broadcast,

at least one of the 2nd-stage SCI or the data is transmitted over a physical sidelink shared channel (PSSCH) to the RX UE;

and

performing data transceiving with the Rx UE based on the 1 st -stage SCI and the 2 nd -stage SCI.