Digital communication using dispersed orthogonal time frequency space modulated signals
Wireless communication transmission and reception techniques are described. At transmitter, source data bits are modulated into a number Nd of constellation symbols. An invertible transform is applied to the constellation symbols, thereby resulting in mapping the transformed symbols into Nd elements in the time-frequency grid. A signal resulting from the invertible transform is transmitted over a communication channel.
1. A wireless communication method, comprising:
modulating source data bits into a number Nd of constellation symbols;
applying an invertible transform to the constellation symbols, resulting in mapping the transformed symbols into Nd elements in a time-frequency grid;
generating a signal by inserting a reference signal and additional data along the time-frequency grid at locations unoccupied by the transformed symbols; and
transmitting the signal resulting from the invertible transform over a communication channel.
2. The method of claim 1 , wherein the mapping in the time-frequency grid includes a partial time-frequency grid, or a full time-frequency grid, or a continuous grid, or a non-continuous grid.
3. The method of claim 1 , wherein the invertible transform and mapping results in spreading a given constellation symbol across multiple locations along the time-frequency grid.
4. The method of claim 3 , wherein the multiple locations are non-continuous along the time-frequency grid.
5. The method of claim 1 , wherein the invertible transform includes a symplectic Fourier transform, or a multi-dimensional Fourier transform, or a permutation transform.
6. The method of claim 1 , wherein the modulating the source data bits includes modulating the source data bits using a multi-layer coding technique in which different constellation bits of a symbol are encoded separately.
7. The method of claim 1 , wherein the number Nd of constellation symbols are constructed from interleaved coded bits.
8. The method of claim 1 , wherein the applying the invertible transform includes arranging the constellation symbols into a multi-dimensional structure and applying the invertible transform to the multi-dimensional structure.
9. A wireless communication method, implementable at a receiver apparatus, comprising:
receiving a signal comprising a logical grouping of Nd symbols arranged in a time-frequency grid, wherein the signal includes a reference signal along the time-frequency grid at locations unoccupied by the Nd symbols;
generating equalized symbols by equalizing the signal by estimating a channel over which the signal is received;
transforming the equalized symbols using an invertible transform into Nd estimated received symbol constellations; and
recovering source data bits from the Nd estimated received symbol constellations.
10. The method of claim 9 , wherein the time-frequency grid includes a partial time-frequency grid, or a full time-frequency grid, or a continuous grid, or a non-continuous grid.
11. The method of claim 9 , wherein a given constellation symbol is spread across multiple locations along the time-frequency grid.
12. The method of claim 11 , wherein the multiple locations are non-continuous along the time-frequency grid.
13. The method of claim 9 , wherein the invertible transform includes a symplectic Fourier transform, or a multi-dimensional Fourier transform, or a permutation transform.
14. The method of claim 9 , wherein the recovering includes at least one of (a) demodulating the source data bits using a multi-layer decoding technique in which different constellation bits of a symbol are decoded separately, or (b) deinterleaving bits from the Nd estimated received symbol constellations.
15. The method of claim 9 , wherein the estimating the channel is based on the reference signal included in the time-frequency grid.
16. The method of claim 9 , wherein the equalizing the received symbols is further based on a priori information about the Nd constellation symbols.
17. The method of claim 16 , wherein the source data bits are recovered by:
computing an extrinsic bit metrics based on the Nd estimated received symbol constellations;
generating estimated coded source data bits from the Nd estimated received symbol constellations; and
providing the estimated coded source data bits as the a priori information.
18. The method of claim 17 , wherein the computing the extrinsic bit metrics is performed using a multi-layer coding scheme.
19. The method of claim 9 , wherein the method is implemented iteratively on a layer by layer basis.
20. The method of claim 9 , wherein the transforming the equalized symbols using the invertible transform includes arranging the equalized symbols into a multi-dimensional structure and applying the invertible transform to the multi-dimensional structure.
21. An apparatus for wireless communication, comprising:
a processor; and
a memory with instructions thereon, wherein the instructions upon execution by the processor cause the processor to:
receive a signal comprising a logical grouping of Nd symbols arranged in a time-frequency grid, wherein the signal includes a reference signal and additional data along the time-frequency grid at locations unoccupied by the Nd symbols;
generate equalized symbols by equalizing the signal by estimating a channel over which the signal is received;
transform the equalized symbols using an invertible transform into Nd estimated received symbol constellations; and
recover source data bits from the Nd estimated received symbol constellations.
22. The apparatus of claim 21 , wherein the time-frequency grid includes a partial time-frequency grid, or a full time-frequency grid, or a continuous grid, or a non-continuous grid.
23. The apparatus of claim 21 , wherein a given constellation symbol is spread across multiple locations along the time-frequency grid.
24. The apparatus of claim 23 , wherein the multiple locations are non-continuous along the time-frequency grid.
25. The apparatus of claim 21 , wherein the invertible transform includes a symplectic Fourier transform, or a multi-dimensional Fourier transform, or a permutation transform.
26. The apparatus of claim 21 , wherein the recovering includes at least one of (a) demodulating the source data bits using a multi-layer decoding technique in which different constellation bits of a symbol are decoded separately, or (b) deinterleaving bits from the Nd estimated received symbol constellations.
27. The apparatus of claim 21 , wherein the estimating the channel is based on the reference signal included in the time-frequency grid.
28. The apparatus of claim 21 , wherein the equalizing the received symbols is further based on a priori information about the Nd constellation symbols.
29. The apparatus of claim 21 , wherein the instructions are executed iteratively on a layer by layer basis.
30. The apparatus of claim 21 , wherein the transforming the equalized symbols using the invertible transform includes arranging the equalized symbols into a multi-dimensional structure and applying the invertible transform to the multi-dimensional structure.