Flexible frequency domain resource allocation for sidelink

1. A method for wireless communications at a first wireless device, comprising:

receiving, via a sidelink channel, control information comprising a parameter associated with a first frequency domain resource allocation of a first transport block associated with an initial transmission and an indication of a second frequency domain resource allocation of a second transport block associated with a subsequent transmission after the initial transmission, wherein the parameter comprises a scaling factor indicating that a size of the first frequency domain resource allocation is different than a size of the second frequency domain resource allocation;

identifying the first frequency domain resource allocation of the first transport block based at least in part on receiving the control information that includes the parameter and the indication;

communicating, with a second wireless device via the sidelink channel, one or more signals based at least in part on identifying the first frequency domain resource allocation of the first transport block and receiving the indication of the second frequency domain resource allocation of the second transport block; and

transmitting, to the second wireless device via the sidelink channel, a request to retransmit a portion of the first transport block, the second transport block comprising the portion of the first transport block based at least in part on the request, and the request comprising an indication of an amount of frequency domain resources for the second transport block.

2. The method of claim 1 , wherein identifying the first frequency domain resource allocation further comprises:

applying the scaling factor to the second frequency domain resource allocation.

3. The method of claim 1 , wherein identifying the first frequency domain resource allocation further comprises:

combining an adjustment factor with the second frequency domain resource allocation, wherein the parameter associated with the first frequency domain resource allocation of the first transport block comprises the adjustment factor.

4. The method of claim 1 , wherein

the parameter comprises a second indication of the first frequency domain resource allocation of the first transport block, and

identifying the first frequency domain resource allocation is based at least in part on the second indication included in the control information.

5. The method of claim 1 , wherein the parameter comprises an index associated with stored values of the first frequency domain resource allocation of the first transport block.

6. The method of claim 5 , further comprising:

identifying a stored value of the stored values that is associated with the index based at least in part on receiving the index, wherein identifying the first frequency domain resource allocation is based at least in part on the stored value.

7. The method of claim 6 , wherein the stored values include one or more frequency domain resources, one or more scaling factors, or one or more adjustment factors associated with the first frequency domain resource allocation.

8. The method of claim 1 , wherein the control information includes a second indication comprising an index associated with stored values of the first frequency domain resource allocation of the first transport block and with stored values of the second frequency domain resource allocation for the second transport block.

9. The method of claim 1 , wherein the indication of the second frequency domain resource allocation of the second transport block comprises an indication of a leading subchannel.

10. The method of claim 1 , further comprising:

receiving, over a second sidelink channel, second control information including a second parameter associated with a size of the second transport block; and

determining the size of the second transport block based at least in part on receiving the second control information.

11. The method of claim 10 , wherein determining the size of the second transport block further comprises:

identifying, within the second control information, code block group information associated with the first transport block, wherein the size of the second transport block is based at least in part on the code block group information.

12. The method of claim 10 , wherein determining the size of the second transport block further comprises:

applying a second scaling factor to a size of the first transport block, wherein the second parameter comprises the second scaling factor.

13. The method of claim 10 , wherein determining the size of the second transport block further comprises:

combining an adjustment factor with a size of the first transport block, wherein the second parameter comprises the adjustment factor.

14. The method of claim 10 , wherein the second parameter comprises a second index associated with stored values associated with transport block size and wherein determining the size of the second transport block further comprises:

identifying a stored value associated with the second index and corresponding to the size of the second transport block.

15. The method of claim 10 , wherein determining the size of the second transport block further comprises:

identifying, within the second control information, a bit field indicating the size of the second transport block.

16. The method of claim 1 , further comprising:

identifying a format associated with the control information, wherein identifying the first frequency domain resource allocation of the first transport block is based at least in part on the format associated with the control information.

17. The method of claim 16 , wherein the control information comprises sidelink control information.

18. The method of claim 1 , wherein the control information is associated with a configured grant for sidelink communications.

19. The method of claim 1 , wherein the control information is communicated over a physical sidelink control channel and the first transport block and the second transport block are communicated over a physical sidelink shared channel.

20. A method for wireless communications at a first wireless device, comprising:

identifying a first frequency domain resource allocation of a first transport block associated with an initial transmission;

identifying a second frequency domain resource allocation of a second transport block associated with a subsequent transmission, wherein identifying the first frequency domain resource allocation is based at least in part on identifying the second frequency domain resource allocation of the second transport block;

transmitting, via a sidelink channel, control information comprising a parameter associated with the first frequency domain resource allocation and an indication of the second frequency domain resource allocation, wherein the parameter comprises a scaling factor indicating that a size of the first frequency domain resource allocation is different than a size of the second frequency domain resource allocation;

communicating, with a second wireless device via the sidelink channel, one or more signals based at least in part on identifying the first frequency domain resource allocation of the first transport block and identifying the second frequency domain resource allocation of the second transport block; and

receiving, from the second wireless device via the sidelink channel, a request to retransmit a portion of the first transport block, the second transport block comprising the portion of the first transport block based at least in part on the request, and the request comprising an indication of an amount of frequency domain resources for the second transport block.

21. The method of claim 20 , wherein transmitting the control information further comprises:

transmitting the control information including an adjustment factor, wherein the parameter comprises the adjustment factor.

22. The method of claim 20 , wherein the parameter comprises a second indication of the first frequency domain resource allocation of the first transport block.

23. The method of claim 20 , further comprising:

determining an index associated with stored values of the first frequency domain resource allocation of the first transport block, wherein the parameter comprises the index.

24. The method of claim 20 , further comprising:

determining a size of the second transport block; and

transmitting, over a second sidelink channel, second control information including a second parameter associated with the size of the second transport block.

25. An apparatus for wireless communications at a first wireless device, comprising:

a processor;

memory coupled with the processor; and

instructions stored in the memory and executable by the processor to cause the apparatus to:

receive, via a sidelink channel, control information comprising a parameter associated with a first frequency domain resource allocation of a first transport block associated with an initial transmission and an indication of a second frequency domain resource allocation of a second transport block associated with a subsequent transmission after the initial transmission, wherein the parameter comprises a scaling factor indicating that a size of the first frequency domain resource allocation is different than a size of the second frequency domain resource allocation;

identify the first frequency domain resource allocation of the first transport block based at least in part on receiving the control information that includes the parameter and the indication;

communicate, with a second wireless device via the sidelink channel, one or more signals based at least in part on identifying the first frequency domain resource allocation of the first transport block and receiving the indication of the second frequency domain resource allocation of the second transport block; and

transmit, to the second wireless device via the sidelink channel, a request to retransmit a portion of the first transport block, the second transport block comprising the portion of the first transport block based at least in part on the request, and the request comprising an indication of an amount of frequency domain resources for the second transport block.

26. An apparatus for wireless communications at a first wireless device, comprising:

a processor;

memory coupled with the processor; and

instructions stored in the memory and executable by the processor to cause the apparatus to:

identify a first frequency domain resource allocation of a first transport block associated with an initial transmission;

identify a second frequency domain resource allocation of a second transport block associated with a subsequent transmission, wherein identifying the first frequency domain resource allocation is based at least in part on identifying the second frequency domain resource allocation of the second transport block;

transmit, via a sidelink channel, control information comprising a parameter associated with the first frequency domain resource allocation and an indication of the second frequency domain resource allocation, wherein the parameter comprises a scaling factor indicating that a size of the first frequency domain resource allocation is different than a size of the second frequency domain resource allocation;

communicate, with a second wireless device via the sidelink channel, one or more signals based at least in part on identifying the first frequency domain resource allocation of the first transport block and identifying the second frequency domain resource allocation of the second transport block; and

receive, from the second wireless device via the sidelink channel, a request to retransmit a portion of the first transport block, the second transport block comprising the portion of the first transport block based at least in part on the request, and the request comprising an indication of an amount of frequency domain resources for the second transport block.