Method and an apparatus for reference signal and mapping for sidelink communications

1. A user equipment for transmission of a demodulation reference signal, DMRS, for sidelink communications, the user equipment comprising:

a processing circuit configured to:

determine at least one transmission parameter associated with at least one of data transmission and control information transmission, the at least one transmission parameter includes at least one of:

at least one of a time position and frequency position of resources associated with a physical channel; and

scheduled bandwidth for the physical channel; and

generate a DMRS using the determined at least one transmission parameter; and

a transmitter circuit configured to transmit the DMRS.

2. The user equipment of claim 1 , wherein the processing circuit is further configured to:

determine a base sequence based on the at least one transmission parameter, the DMRS being generated based on the base sequence.

3. The user equipment of claim 2 , wherein the base sequence is generated for each Orthogonal Frequency Division Multiplexing, OFDM, symbol that carries the DMRS, the base sequence being based on the at least one transmission parameter.

4. The user equipment of claim 2 , wherein the processing circuit is further configured to:

determine a cyclic shift, CS, based on the at least one transmission parameter, the CS being applied to each base sequence.

5. The user equipment of claim 1 , wherein the processing circuit is further configured to:

determine a cyclic shift, CS, based on the at least one transmission parameter, the DMRS being generated based on the CS.

6. The user equipment of claim 1 , wherein the processing circuit is further configured to:

determine an orthogonal cover code, OCC, based on the at least one transmission parameter, the DMRS being generated based on the OCC.

7. The user equipment of claim 6 , wherein the OCC is applied in a time domain to symbols of the DMRS.

8. The user equipment of claim 1 , wherein the at least one of the time position and frequency position of resources associated with the physical channel includes a frequency position of resources associated with at least one of data transmission and control information transmission; and

the at least one transmission parameter includes at least one of:

a priority of content included in a Physical Sidelink Control Channel, PSCCH; and

a number of transmissions of a transmission block.

9. The user equipment of claim 1 , wherein the physical channel is one of a Physical Sidelink Control Channel, PSCCH, and a Physical Sidelink Shared Channel, PSSCH.

10. The user equipment of claim 1 , wherein the at least one of the time position and frequency position of resources associated with a physical channel is at least one parameter of a scheduling assignment associated with at least one of the data transmission and the control information transmission.

11. The user equipment of claim 1 , wherein the processing circuit is further configured to:

map the DMRS to a plurality of resources elements of a plurality of subcarriers; and

the plurality of subcarriers having subcarrier indices of {k, n+k, 2n+k, 3n+k, . . . }, where k is greater than 0, and n is greater than k.

12. A method for a user equipment for transmission of demodulation reference signal, DMRS, for sidelink communications, the method comprising:

determining at least one transmission parameter associated with at least one of data transmission and control information transmission, the at least one transmission parameter includes at least one of:

at least one of a time position and frequency position of resources associated with a physical channel; and

scheduled bandwidth for the physical channel; and

generating a DMRS using the determined at least one transmission parameter; and

transmitting the DMRS.

13. The method of claim 12 , further comprising:

determining a base sequence based on the at least one transmission parameter, the DMRS being generated based on the base sequence.

14. The method of claim 13 , wherein the base sequence is generated for each Orthogonal Frequency Division Multiplexing, OFDM, symbol that carries the DMRS, the base sequence being based on the at least on transmission parameter.

15. The method of claim 13 , wherein the processing circuit is further configured to:

determine a cyclic shift, CS, based on the at least one transmission parameter, the CS being applied to each base sequence.

16. The method of claim 12 , further comprising:

determining a cyclic shift, CS, based on the at least one transmission parameter, the DMRS being generated based on the CS.

17. The method of claim 12 , further comprising:

determining an orthogonal cover code, OCC, based on the at least one transmission parameter, the DMRS being generated based on the OCC.

18. The method of claim 17 , wherein the OCC is applied in a time domain to symbols of the DMRS.

19. The method of claim 12 , wherein the at least one of the time position and frequency position of resources associated with the physical channel includes a frequency position of resources associated with at least one of data transmission and control information transmission; and

the at least one transmission parameter includes at least one of:

a priority of content included in a Physical Sidelink Control Channel, PSCCH; and

a number of transmissions of a transmission block.

20. The method of claim 12 , wherein the physical channel is one of a Physical Sidelink Control Channel, PSCCH, and a Physical Sidelink Shared Channel, PSSCH.

21. The method of claim 12 , wherein the at least one of the time position and frequency position of resources associated with a physical channel is at least one parameter of a scheduling assignment associated with at least one of the data transmission and the control information transmission.

22. The method of claim 12 , further comprising:

mapping the DMRS to a plurality of resources elements of a plurality of subcarriers; and

the plurality of subcarriers having subcarrier indices of {k, n+k, 2n+k, 3n+k, . . . }, where k is greater than 0, and n is greater than k.

23. A user equipment for transmission of demodulation reference signal, DMRS, for sidelink communications, the user equipment comprising:

a processing module configured to:

determine at least one transmission parameter associated with at least one of data transmission and control information transmission, the at least one transmission parameter includes at least one of:

at least one of a time position and frequency position of resources associated with a physical channel; and

scheduled bandwidth for the physical channel; and

generate a DMRS using the determined at least one transmission parameter; and

transmitter module configured to transmit the DMRS.