Localized equalization for channels with intercarrier interference
A wireless communication method for receiving an orthogonal time frequency space (OTFS) modulated signal includes receiving the OTFS signal over a wireless communication channel, dividing the receiving OTFS signal along a delay-dimension into a plurality of segments, performing, for each segment, channel estimation independent of channel estimation for other segments to generate a plurality of channel estimates, performing, for each segment, channel equalization using a corresponding channel estimate from the plurality of channel estimates to generate a channel-equalized symbol stream, and generating information bits from the channel-equalized symbol stream.
1. A wireless communication method for receiving an orthogonal time frequency space (OTFS) modulated signal, comprising:
receiving the OTFS modulated signal over a wireless communication channel;
dividing the OTFS modulated signal along a delay-dimension into a plurality of segments;
performing, for each segment, channel estimation to produce a plurality of channel estimates corresponding to the plurality of segments;
performing, for each segment, channel equalization using a corresponding channel estimate from the plurality of channel estimates to generate a channel-equalized symbol stream; and
generating information bits from the channel-equalized symbol stream.
2. The wireless communication method of claim 1 , wherein each segment has an equal duration in the delay-dimension.
3. The wireless communication method of claim 1 , wherein the performing the channel equalization includes performing a minimum mean square error based channel equalization.
4. The wireless communication method of claim 1 , wherein the performing the channel equalization includes performing a turbo equalization using information from decoded information bits in an iterative manner.
5. The wireless communication method of claim 1 , wherein the generating information bits operation comprises decoding and demapping constellation symbols.
6. The wireless communication method of claim 1 , wherein the generating the information bits comprises calculating log-likelihood ratios of the information bits.
7. The wireless communication method of claim 1 , where the OTFS modulated signal has Doppler dimension length equal to one, reducing to a single carrier frequency domain multiple access (SC-FDMA) modulated signal.
8. A wireless communication device comprising a memory storing instructions and a processor, wherein the instructions, when executed by the processor, cause the processor to at least:
receive an orthogonal time frequency space (OTFS) modulated signal over a wireless communication channel;
divide the OTFS modulated signal along a delay-dimension into a plurality of segments;
perform, for each segment, channel estimation to produce a plurality of channel estimates corresponding to the plurality of segments;
perform, for each segment, channel equalization using a corresponding channel estimate from the plurality of channel estimates to generate a channel-equalized symbol stream; and
generate information bits from the channel-equalized symbol stream.
9. The wireless communication device of claim 8 , wherein each segment has an equal duration in the delay-dimension.
10. The wireless communication device of claim 8 , wherein the performing the channel equalization includes performing a minimum mean square error based channel equalization.
11. The wireless communication device of claim 8 , wherein the performing the channel equalization includes performing a turbo equalization using information from decoded information bits in an iterative manner.
12. The wireless communication device of claim 8 , wherein the generating the information bits operation comprises decoding and demapping constellation symbols.
13. The wireless communication device of claim 8 , wherein the generating the information bits comprises calculating log-likelihood ratios of the information bits.
14. The wireless communication device of claim 8 , where the OTFS modulated signal has Doppler dimension length equal to one, reducing to a single carrier frequency domain multiple access (SC-FDMA) modulated signal.
15. A wireless communication system, comprising:
a transmitter configured to:
pre-process, based on a set of basis functions, information bits to generate a plurality of pre-processed symbols,
modulate, using an orthogonal time frequency space (OTFS) transformation, the plurality of pre-processed symbols to generate an OTFS modulated signal, and
transmit the OTFS modulated signal over a wireless communication channel; and
a receiver configured to:
receive the OTFS modulated signal over the wireless communication channel, divide the OTFS modulated signal along a delay-dimension into a plurality of segments,
perform, for each segment, channel estimation to produce a plurality of channel estimates corresponding to the plurality of segments,
perform, for each segment, channel equalization using a corresponding channel estimate from the plurality of channel estimates to generate a channel-equalized symbol stream, and
generate the information bits from the channel-equalized symbol stream.
16. The wireless communication system of claim 15 , wherein the set of basis functions comprise a set of two-dimensional exponential basis functions.
17. The wireless communication system of claim 16 , wherein the OTFS transformation comprises a two-dimensional Symplectic discrete Fourier Transform (DFT).
18. The wireless communication system of claim 15 , wherein each segment has an equal duration in the delay-dimension.
19. The wireless communication system of claim 15 , wherein the generating the information bits operation comprises decoding and demapping constellation symbols.
20. The wireless communication system of claim 15 , wherein the generating the information bits comprises calculating log-likelihood ratios of the information bits.