Grant-free uplink transmission in unlicensed spectrum

1. A method for communicating in a wireless communication network, the method comprising:

receiving, by an electronic device (ED) in a group of EDs, grant-free group-specific resource configuration information from a base station, the grant-free group-specific resource configuration information specifying parameters including at least a period and a channel occupancy time (COT) duration for semi-static access of at least one channel of an unlicensed spectrum; and

transmitting, by the ED, a grant-free uplink transmission over the at least one channel of the unlicensed spectrum in accordance with the period and the COT duration specified by the grant-free group-specific resource configuration information and a reference start time.

2. The method of claim 1 , wherein the grant-free group-specific resource configuration information is received via a group-specific configuration message.

3. The method of claim 1 , wherein the grant-free group-specific resource configuration information is received via an ED-specific configuration message.

4. The method of claim 1 , wherein all of the parameters specified by the grant-free group-specific resource configuration information are received via radio resource control (RRC) signaling.

5. The method of claim 1 , wherein a first subset of the parameters specified by the grant-free group-specific resource configuration information are received via radio resource control (RRC) signaling and a second subset of the parameters specified by the grant-free group-specific resource configuration information is received via downlink control information (DCI) signaling, at least one parameter in the first subset of parameters being excluded from the second subset of parameters, or vice-versa.

6. The method of claim 1 , wherein the grant-free group-specific resource configuration information further indicates that EDs in a corresponding group of EDs, including the ED, are required to perform a channel access procedure to access the at least one channel of the unlicensed spectrum, the channel access procedure comprising performing a clear channel assessment (CCA) within one or more symbols of the at least one channel of the unlicensed spectrum prior to the reference start time.

7. The method of claim 6 , wherein transmitting the grant-free uplink transmission over the unlicensed spectrum in accordance with the parameters specified by the grant-free group-specific resource configuration information comprises:

performing a clear channel assessment (CCA) on the at least one channel of the unlicensed spectrum in accordance with the indication that EDs in the corresponding group of EDs are required to perform the CCA on the at least one channel of the unlicensed spectrum, and based thereon transmitting the grant-free uplink transmission over the at least one channel of the unlicensed spectrum.

8. The method of claim 7 , wherein the ED accesses the at least one channel of the unlicensed spectrum as a frame based equipment (FBE), and wherein transmitting the grant-free uplink transmission over the unlicensed spectrum comprises:

performing a short energy-detection-based clear channel assessment (CCA) for a deterministic duration on a shared channel in accordance with the indication that EDs in the corresponding group of EDs are required to perform the CCA on the at least one channel of the unlicensed spectrum, and based thereon transmitting the grant-free uplink transmission during an instance of a periodic interval in accordance with the period specified by the grant-free group-specific resource configuration information, the period being an FBE fixed frame period.

9. The method of claim 1 , wherein the ED determines the reference start time based on the period and a current timer value of any one of a system frame number (SFN), subframe number, and slot number.

10. The method of claim 1 , wherein the grant-free group-specific resource configuration information further indicates whether time-frequency resources coinciding with the COT duration are permitted to be shared with downlink transmissions from the base station.

11. The method of claim 10 , wherein the period is based on a minimum FBE idle period.

12. The method of claim 11 , wherein the period is based on an uplink grant-free COT duration.

13. The method of claim 12 , wherein the uplink grant-free COT duration is a maximum COT (MCOT) duration and the ED determines the MCOT duration as a fraction of the period based on the minimum FBE idle period.

14. The method of claim 10 , wherein the period is based on at least one of a subcarrier spacing and a grant-free frame structure.

15. The method in claim 1 , wherein the parameters specified by the grant-free group-specific resource configuration information further include a channel access priority class (CAPC) index and wherein the method further comprises:

determining, by the ED, a maximum grant-free burst length based on the priority class index specified by the grant-free group-specific resource configuration information and at least one of a grant-free frame structure and numerology associated with the grant-free uplink transmission.

16. The method of claim 1 , wherein the grant-free group-specific resource configuration information further indicates a plurality of grant-free transmission opportunities within the period.

17. The method of claim 16 , wherein the grant-free transmission opportunities include at least two grant-free transmission opportunities associated with different sets of parameters for accessing the at least one channel of the unlicensed spectrum.

18. The method of claim 1 , wherein the grant-free uplink transmission includes uplink control information that is carried at the beginning of a grant-free uplink transmission.

19. The method of claim 18 , wherein the uplink control information includes at least one channel access priority class (CAPC) parameter.

20. The method of claim 1 , wherein the reference start time is configured by the grant-free group-specific configuration information.

21. An electronic device (ED) in a group of EDs, the ED comprising:

a processor; and

a non-transitory computer readable storage medium storing programming for execution by the processor, the programming including instructions to:

receive grant-free group-specific resource configuration information from a base station, the grant-free group-specific resource configuration information specifying parameters including at least a period and a channel occupancy time (COT) duration for semi-static access of at least one channel of an unlicensed spectrum; and

transmit a grant-free uplink transmission over the at least one channel of the unlicensed spectrum in accordance with the period and the COT duration specified by the grant-free group-specific resource configuration information and a reference start time.

22. The ED of claim 21 , wherein the grant-free group-specific resource configuration information is received via a group-specific configuration message.

23. The ED of claim 21 , wherein the grant-free group-specific resource configuration information is received via an ED-specific configuration message.

24. The ED of claim 21 , wherein all of the parameters specified by the grant-free group-specific resource configuration information are received via radio resource control (RRC) signaling.

25. The ED of claim 21 , wherein the reference start time is configured by the grant-free group-specific configuration information.