Multi-symbol self-contained waveform design

1. A method for wireless communications, comprising:

receiving a waveform formed by one or more reference signal symbols and one or more data symbols, the waveform contained between a beginning boundary and an ending boundary with a duration equal to a total length of the one or more reference signal symbols and the one or more data symbols, wherein a segment of a reference signal sequence of a reference signal symbol of the one or more reference signal symbols is repeated as a beginning segment or an ending segment in at least one data symbol of the one or more data symbols as a guard interval;

performing a fast Fourier transform (FFT) on the waveform in symbol length window increments to generate FFT output; and

demodulating data from the FFT output.

2. The method of claim 1 , wherein demodulating the data comprises:

generating a channel estimate based at least in part on a subset of the FFT output corresponding to the one or more reference signal symbols; and

demodulating the data from the FFT output based at least in part on the channel estimate.

3. The method of claim 1 , further comprising:

shifting a first symbol length window increment of the symbol length window increments corresponding to the reference signal symbol of the one or more reference signal symbols by a length of the beginning segment of the reference signal sequence when first and second reference signal symbols of the one or more reference signal symbols are adjacent and each includes the reference signal sequence, wherein the FFT is performed on the reference signal symbol using the shifted first symbol length window increment.

4. The method of claim 1 , further comprising:

shifting a first symbol length window increment of the symbol length window increments corresponding to the reference signal symbol of the one or more reference signal symbols by a length of the beginning segment of the reference signal sequence when first and second reference signal symbols of the one or more reference signal symbols are adjacent.

5. The method of claim 4 , wherein a first reference signal segment is included as a beginning segment in each of the first and second reference signal symbols and a second reference signal segment is included as an ending segment in each of the first and second reference signal symbols, and different middle reference signal segments are respectively included as middle segments in each of the first and second reference signal symbols.

6. The method of claim 4 , wherein the FFT is performed on the first reference signal symbol using the shifted first symbol length window increment and on the second reference signal symbol using a symbol length window increment aligned with a symbol boundary between the first and second reference signal symbols.

7. The method of claim 1 , wherein the beginning segment of the reference signal sequence of the reference signal symbol of the one or more reference signal symbols is repeated as the beginning segment in each data symbol of the one or more data symbols that occurs prior to the reference signal symbol as the guard interval, the method further comprising:

shifting each of the symbol length window increments that occur prior to the reference signal symbol by a length of the beginning segment, wherein the FFT is performed on a subset of the one or more data symbols that occur prior to the reference signal symbol using a respective shifted symbol length window increment of the shifted symbol length window increments.

8. The method of claim 1 , wherein the ending segment of the reference signal sequence of the reference signal symbol of the one or more reference signal symbols is repeated as the ending segment in each data symbol of the one or more data symbols that occur after the reference signal symbol as the guard interval, the method further comprising:

aligning each of the symbol length window increments that occur after the reference signal symbol with a symbol period boundary, wherein the FFT is performed on each data symbol of the one or more data symbols that occur after the reference signal symbol using the aligned symbol length window increments.

9. The method of claim 1 , wherein the one or more reference signal symbols is a single reference signal symbol, and wherein a beginning segment of a reference signal sequence included in the single reference signal symbol is repeated as a beginning segment in a data symbol of the one or more data symbols that occurs right after the single reference signal symbol as a guard interval.

10. The method of claim 1 , wherein the one or more reference signal symbols is a single reference signal symbol, and wherein a beginning segment of a reference signal sequence included in the single reference signal symbol is repeated as a beginning segment in a data symbol of the one or more data symbols that occurs right before the single reference signal symbol as a guard interval.

11. The method of claim 1 , wherein the one or more reference signal symbols is a single reference signal symbol, and wherein a beginning segment of a reference signal sequence included in the single reference signal symbol is repeated as a beginning segment in all data symbols of the one or more data symbols that occur before and after the single reference signal symbol as a guard interval, and wherein an ending segment of the reference signal sequence is repeated as an ending segment in all the data symbols that occur before and after the single reference signal symbol as a guard interval.

12. The method of claim 1 , wherein the waveform is formed by concatenating a first waveform generated for a first group of the one or more reference signal symbols and of the one or more data symbols and a second waveform generated for a second group of the one or more reference signal symbols and of the one or more data symbols.

13. An apparatus for wireless communications, 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 a waveform formed by one or more reference signal symbols and one or more data symbols, the waveform contained between a beginning boundary and an ending boundary with a duration equal to a total length of the one or more reference signal symbols and the one or more data symbols, wherein a segment of a reference signal sequence of a reference signal symbol of the one or more reference signal symbols is repeated as a beginning segment or an ending segment in at least one data symbol of the one or more data symbols as a guard interval;

perform a fast Fourier transform (FFT) on the waveform in symbol length window increments to generate FFT output; and

demodulate data from the FFT output.

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

generate a channel estimate based at least in part on a subset of the FFT output corresponding to the one or more reference signal symbols; and

demodulate the data from the FFT output based at least in part on the channel estimate.

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

shift a first symbol length window increment of the symbol length window increments corresponding to the reference signal symbol of the one or more reference signal symbols by a length of the beginning segment of the reference signal sequence when first and second reference signal symbols of the one or more reference signal symbols are adjacent and each includes the reference signal sequence, wherein the FFT is performed on the reference signal symbol using the shifted first symbol length window increment.

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

shift a first symbol length window increment of the symbol length window increments corresponding to the reference signal symbol of the one or more reference signal symbols by a length of the beginning segment of the reference signal sequence when first and second reference signal symbols of the one or more reference signal symbols are adjacent.

17. The apparatus of claim 13 , wherein the beginning segment of the reference signal sequence of the reference signal symbol of the one or more reference signal symbols is repeated as a beginning segment in each data symbol of the one or more data symbols that occurs prior to the reference signal symbol as the guard interval, wherein the instructions are further executable by the processor to:

shift each of the symbol length window increments that occur prior to the reference signal symbol by a length of the beginning segment, wherein the FFT is performed on a subset of the one or more data symbols that occur prior to the reference signal symbol using a respective shifted symbol length window increment of the shifted symbol length window increments.

18. The apparatus of claim 13 , wherein the ending segment of the reference signal sequence of the reference signal symbol of the one or more reference signal symbols is repeated as an ending segment in each data symbol of the one or more data symbols that occur after the reference signal symbol as the guard interval, wherein the instructions are further executable by the processor to:

align each of the symbol length window increments that occur after the reference signal symbol with a symbol period boundary, wherein the FFT is performed on each data symbol of the one or more data symbols that occur after the reference signal symbol using the aligned symbol length window increments.

19. The apparatus of claim 13 , wherein the one or more reference signal symbols is a single reference signal symbol, and wherein a beginning segment of a reference signal sequence included in the single reference signal symbol is repeated as a beginning segment in a data symbol of the one or more data symbols that occurs right after the single reference signal symbol as a guard interval.

20. The apparatus of claim 13 , wherein the one or more reference signal symbols is a single reference signal symbol, and wherein a beginning segment of a reference signal sequence included in the single reference signal symbol is repeated as a beginning segment in a data symbol of the one or more data symbols that occurs right before the single reference signal symbol as a guard interval.

21. The apparatus of claim 13 , wherein the one or more reference signal symbols is a single reference signal symbol, and wherein a beginning segment of a reference signal sequence included in the single reference signal symbol is repeated as a beginning segment in all data symbols of the one or more data symbols that occur before and after the single reference signal symbol as a guard interval, and wherein an ending segment of the reference signal sequence is repeated as an ending segment in all the data symbols that occur before and after the single reference signal symbol as a guard interval.

22. The apparatus of claim 13 , wherein the waveform is formed by concatenating a first waveform generated for a first group of the one or more reference signal symbols and of the one or more data symbols and a second waveform generated for a second group of the one or more reference signal symbols and of the one or more data symbols.

23. An apparatus for wireless communications, comprising:

means for receiving a waveform formed by one or more reference signal symbols and one or more data symbols, the waveform contained between a beginning boundary and an ending boundary with a duration equal to a total length of the one or more reference signal symbols and the one or more data symbols, wherein a segment of a reference signal sequence of a reference signal symbol of the one or more reference signal symbols is repeated as a beginning segment or an ending segment in at least one data symbol of the one or more data symbols as a guard interval;

means for performing a fast Fourier transform (FFT) on the waveform in symbol length window increments to generate FFT output; and

means for demodulating data from the FFT output.

24. The apparatus of claim 23 , wherein the means for demodulating the data comprises:

means for generating a channel estimate based at least in part on a subset of the FFT output corresponding to the one or more reference signal symbols; and

means for demodulating the data from the FFT output based at least in part on the channel estimate.

25. The apparatus of claim 23 , further comprising:

means for shifting a first symbol length window increment of the symbol length window increments corresponding to the reference signal symbol of the one or more reference signal symbols by a length of the beginning segment of the reference signal sequence when first and second reference signal symbols of the one or more reference signal symbols are adjacent and each includes the reference signal sequence, wherein the FFT is performed on the reference signal symbol using the shifted first symbol length window increment.

26. The apparatus of claim 23 , further comprising:

means for shifting a first symbol length window increment of the symbol length window increments corresponding to the reference signal symbol of the one or more reference signal symbols by a length of the beginning segment of the reference signal sequence when first and second reference signal symbols of the one or more reference signal symbols are adjacent.

27. The apparatus of claim 26 , wherein a first reference signal segment is included as a beginning segment in each of the first and second reference signal symbols and a second reference signal segment is included as an ending segment in each of the first and second reference signal symbols, and different middle reference signal segments are respectively included as middle segments in each of the first and second reference signal symbols.

28. The apparatus of claim 26 , wherein the FFT is performed on the first reference signal symbol using the shifted symbol length window increment and on the second reference signal symbol using a symbol length window increment aligned with a symbol boundary between the first and second reference signal symbols.

29. The apparatus of claim 23 , wherein the beginning segment of the reference signal sequence of the reference signal symbol of the one or more reference signal symbols is repeated as a beginning segment in each data symbol of the one or more data symbols that occurs prior to the reference signal symbol as the guard interval, the apparatus further comprising:

means for shifting each of the symbol length window increments that occur prior to the reference signal symbol by a length of the beginning segment, wherein the FFT is performed on a subset of the one or more data symbols that occur prior to the reference signal symbol using a respective shifted symbol length window increment of the shifted symbol length window increments.

30. A non-transitory computer-readable medium storing code for wireless communications, the code comprising instructions executable by a processor to:

receive a waveform formed by one or more reference signal symbols and one or more data symbols, the waveform contained between a beginning boundary and an ending boundary with a duration equal to a total length of the one or more reference signal symbols and the one or more data symbols, wherein a segment of a reference signal sequence of a reference signal symbol of the one or more reference signal symbols is repeated as a beginning segment or an ending segment in at least one data symbol of the one or more data symbols as a guard interval;

perform a fast Fourier transform (FFT) on the waveform in symbol length window increments to generate FFT output; and

demodulate data from the FFT output.