Enhancements to phase-noise compensation reference signal design and scrambling

1. A method for wireless communication, comprising:

identifying a frequency corresponding to a direct current (DC) tone within a set of resource blocks;

determining a frequency for each of one or more phase-noise tracking reference signals (PTRS) based at least in part on the DC tone, each determined frequency different from the frequency corresponding to the DC tone; and

transmitting the one or more PTRS using the set of resource blocks based at least in part on the determined frequency.

2. The method of claim 1 , further comprising:

transmitting an indication of the identified frequency corresponding to the DC tone.

3. The method of claim 1 , further comprising:

identifying that a resource block of the set of resource blocks overlaps with the DC tone, wherein the one or more PTRS are transmitted using one or more resource blocks of the set of resource blocks that are different from the resource block including the DC tone.

4. The method of claim 1 , further comprising:

identifying that each resource block of the set of resource blocks includes at least some of the one or more PTRS, wherein the determining is based at least in part on identifying that each resource block includes at least some of the one or more PTRS.

5. The method of claim 1 , further comprising:

identifying that a first resource block of the set of resource blocks overlaps with the DC tone, wherein the determining comprises assigning at least some of the one or more PTRS to one or more frequencies of the first resource block.

6. The method of claim 1 , wherein the frequency corresponding to each of the one or more PTRS is based at least in part on a number of component carriers, a system bandwidth, or both.

7. The method of claim 1 , wherein a frequency density of the PTRS is based at least in part on a number of resource blocks in the set of resource blocks.

8. The method of claim 1 , further comprising:

identifying a plurality of tones across the set of resource blocks different from the frequency corresponding to the DC tone, the plurality of tones corresponding to a plurality of symbols across the set of resource blocks and associated with at least one antenna port;

assigning a first subset of the plurality of tones for data;

assigning a second subset of the plurality of tones for PTRS;

scrambling a modulation symbol for each tone of the second subset; and

transmitting the first subset and the second subset using the scrambled modulation symbols.

9. The method of claim 8 , wherein the transmitting comprises transmitting the second subset using the at least one antenna port based at least in part on a resource block assignment, the resource block assignment comprising a number of layers used for data in the set of resource blocks.

10. The method of claim 8 , wherein the second subset corresponds to an antenna port of the at least one antenna port, the method further comprising:

refraining from transmitting PTRS using the antenna port; and

reassigning the second subset for data or a vacant tone.

11. The method of claim 8 , wherein the second subset corresponds to an antenna port of the at least one antenna port and contains at most one tone per resource block of the set of resource blocks, the method further comprising:

assigning a third subset of the plurality of tones for a demodulation reference signal (DMRS), the third subset and the first subset overlapping partially, overlapping completely, or being disjoint, and the third subset corresponding to a group of antenna ports of the at least one antenna port; and

transmitting the third subset using the group of antenna ports, wherein the third subset comprises each of the at most one tone per resource block of the set of resource blocks.

12. A method for wireless communication, comprising:

generating a discrete Fourier transform-spread-orthogonal frequency division multiplexing (DFT-s-OFDM) symbol, the generating comprising appending a phase-noise tracking reference signal (PTRS) to an output of an inverse fast Fourier transform (IFFT) operation used to generate the DFT-s-OFDM symbol;

appending a cyclic prefix to the generated DFT-s-OFDM symbol; and

transmitting the generated DFT-s-OFDM symbol comprising the cyclic prefix and the PTRS.

13. An apparatus for wireless communication, the apparatus comprising:

a processor;

memory in electronic communication with the processor; and

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

identify a frequency corresponding to a direct current (DC) tone within a set of resource blocks;

determine a frequency for each of one or more phase-noise tracking reference signals (PTRS) based at least in part on the DC tone, each determined frequency different from the frequency corresponding to the DC tone; and

transmit the one or more PTRS using the set of resource blocks based at least in part on the determined frequency.

14. The apparatus of claim 13 , wherein the instructions are further executable by the processor to cause the apparatus to:

transmit an indication of the identified frequency corresponding to the DC tone.

15. The apparatus of claim 13 , wherein the instructions are further executable by the processor to cause the apparatus to:

identify that a resource block of the set of resource blocks overlaps with the DC tone, wherein the one or more PTRS are transmitted using one or more resource blocks of the set of resource blocks that are different from the resource block including the DC tone.

16. The apparatus of claim 13 , wherein the instructions are further executable by the processor to cause the apparatus to:

identify that each resource block of the set of resource blocks includes at least some of the one or more PTRS, wherein the determining is based at least in part on identifying that each resource block includes at least some of the one or more PTRS.

17. The apparatus of claim 13 , wherein the instructions are further executable by the processor to cause the apparatus to:

identify that a first resource block of the set of resource blocks overlaps with the DC tone, wherein the determining comprises assigning at least some of the one or more PTRS to one or more frequencies of the first resource block.

18. The apparatus of claim 13 , wherein the frequency corresponding to each of the one or more PTRS is based at least in part on a number of component carriers, a system bandwidth, or both.

19. The apparatus of claim 13 , wherein the instructions are further executable by the processor to cause the apparatus to:

identify a plurality of tones across the set of resource blocks different from the frequency corresponding to the DC tone, the plurality of tones corresponding to a plurality of symbols across the set of resource blocks and associated with at least one antenna port;

assign a first subset of the plurality of tones for data;

assign a second subset of the plurality of tones for phase-noise tracking reference signals (PTRS);

scramble a modulation symbol for each tone of the second subset; and

transmit the first subset and the second subset using the scrambled modulation symbols.

20. The apparatus of claim 19 , wherein the transmitting comprises transmitting the second subset using the at least one antenna port based at least in part on a resource block assignment, the resource block assignment comprising a number of layers used for data in the set of resource blocks.

21. The apparatus of claim 19 , wherein the second subset corresponds to an antenna port of the at least one antenna port and contains at most one tone per resource block of the set of resource blocks, and the instructions are further executable by the processor to cause the apparatus to:

assign a third subset of the plurality of tones for a demodulation reference signal (DMRS), the third subset and the first subset overlapping partially, overlapping completely, or being disjoint, and the third subset corresponding to a group of antenna ports of the at least one antenna port; and

transmit the third subset using the group of antenna ports, wherein the third subset comprises each of the at most one tone per resource block of the set of resource blocks.

22. An apparatus for wireless communication, the apparatus comprising:

a processor;

memory in electronic communication with the processor; and

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

generate a discrete Fourier transform-spread-orthogonal frequency division multiplexing (DFT-s-OFDM) symbol, the generating comprising appending a phase-noise tracking reference signal (PTRS) to an output of an inverse fast Fourier transform (IFFT) operation used to generate the DFT-s-OFDM symbol;

append a cyclic prefix to the generated DFT-s-OFDM symbol; and

transmit the generated DFT-s-OFDM symbol comprising the cyclic prefix and the PTRS.

23. The method of claim 12 , wherein the cyclic prefix is appended to the beginning of the generated DFT-s-OFDM symbol and the PTRS is appended to a beginning of the cyclic prefix, to an end of the generated DFT-s-OFDM symbol, or a combination thereof.

24. The method of claim 12 , wherein the generated DFT-s-OFDM symbol comprises a guard interval, and wherein the appending the PTRS to the generated DFT-s-OFDM symbol comprises replacing at least a portion of the guard interval with the PTRS.

25. The method of claim 12 , further comprising:

performing a weighted-overlap-and-add scheme within the generated DFT-s-OFDM symbol at a boundary between the generated DFT-s-OFDM symbol and the appended PTRS.

26. The apparatus of claim 22 , wherein the cyclic prefix is appended to the beginning of the generated DFT-s-OFDM symbol and the PTRS is appended to a beginning of the cyclic prefix, to an end of the generated DFT-s-OFDM symbol, or a combination thereof.

27. The apparatus of claim 22 , wherein the generated DFT-s-OFDM symbol comprises a guard interval, and wherein the appending the PTRS to the generated DFT-s-OFDM symbol comprises replacing at least a portion of the guard interval with the PTRS.

28. The apparatus of claim 22 , wherein the instructions are further executable by the processor to cause the apparatus to:

perform a weighted-overlap-and-add scheme within the generated DFT-s-OFDM symbol at a boundary between the generated DFT-s-OFDM symbol and the appended PTRS.