MODULATION AND EQUALIZATION IN AN ORTHONORMAL TIME-FREQUENCY SHIFTING COMMUNICATIONS SYSTEM

• US 20190215109A1
• Filed: 07/24/2018
• Published: 07/11/2019
• Est. Priority Date: 05/28/2010
• Status: Active Grant

• Current Assignee: Cohere Technologies Inc
• Original Assignee: Cohere Technologies Inc
• Inventors: Hadani, Ronny, Rakib, Shlomo Selim
• Granted Patent: US 10,567,125 B2
• Time in Patent Office: Days
• CPC Class Codes: H04B 7/005 Control of transmission; Equalising
• CPC Class Codes: H04L 23/02 adapted for orthogonal signalling
• CPC Class Codes: H04L 25/03343 Arrangements at the transmitter end
• CPC Class Codes: H04L 25/03834 using pulse shaping
• CPC Class Codes: H04L 27/01 Equalisers baseband equalizers at the transmitter end H04L25/03343; in analogue transmission systems H04B3/04, H04B7/005
• CPC Class Codes: H04L 27/10 Frequency-modulated carrier systems, i.e. using frequency-shift keying H04L27/32 takes precedence
• CPC Class Codes: H04L 27/2639 Modulators using other transforms, e.g. discrete cosine transforms, Orthogonal Time Frequency and Space [OTFS] or hermetic transforms
• CPC Class Codes: H04L 27/26532 Demodulators using other transforms, e.g. discrete cosine transforms, Orthogonal Time Frequency and Space [OTFS] or hermetic transforms
• CPC Class Codes: H04L 27/2655 Synchronisation arrangements
• CPC Class Codes: H04L 27/2697 in combination with other modulation techniques
• CPC Class Codes: H04L 5/0005 Time-frequency
• CPC Class Codes: H04L 5/0016 Time-frequency-code
• CPC Class Codes: H04L 5/0044 allocation of payload

Abstract

A method for modulating data for transmission within a communication system. The method includes establishing a time-frequency shifting matrix of dimension N×N, wherein N is greater than one. The method further includes combining the time-frequency shifting matrix with a data frame to provide an intermediate data frame. A transformed data matrix is provided by permuting elements of the intermediate data frame. A modulated signal is generated in accordance with elements of the transformed data matrix.

Claims

1-12. -12. (canceled)

13. A method for wireless communication, comprising:

transforming a data frame with N² data symbols into a time frequency shifted (TFS) data matrix with N² elements, wherein each of the N² elements carries information corresponding to all N² data symbols;

generating, based on a feedback signal, a pre-equalized TFS data matrix by performing a pre-equalization operation on the TFS data matrix;

generating N composite waveforms based on modulating each column of the pre-equalized TFS data matrix; and

transmitting each of the N composite waveforms as a pre-equalized orthonormal time frequency space (OTFS) signal.

14. The method of claim 13, wherein modulating a column of the pre-equalized TFS data matrix comprises:

separating each element of the column into real and imaginary components;

filtering the real and imaginary components to generate filtered real and imaginary components; and

controlling, using the filtered real and imaginary components, an operation of a cosine and sine generator, respectively.

15. The method of claim 13, wherein the N composite waveforms comprise N² summation-symbol-weighted cyclically time shifted and cyclically frequency shifted waveforms.

16. The method of claim 13, wherein the generating the pre-equalized TFS data matrix comprises:

receiving the feedback signal;

generating, based on the feedback signal, a pre-distortion transfer function that corresponds to a wireless channel; and

configuring, based on the pre-distortion transfer function, the pre-equalization operation.

17. The method of claim 16, wherein the wireless channel comprises an echo reflection, and wherein the pre-equalization operation comprises an anti-echo cancellation waveform.

18. The method of claim 16, wherein the wireless channel comprises a frequency shift, and wherein the pre-equalization operation comprises a compensatory reverse frequency shift.

19. The method of claim 13, wherein the transmitting each of the N composite waveforms comprises transmitting over a plurality of time blocks or a plurality of frequency blocks.

20. A method for wireless communication, comprising:

receiving each of N orthonormal time frequency space (OTFS) signals;

constructing, based on the N OTFS signals, a received data matrix;

generating an equalized data matrix with N² elements by performing an equalization operation on the received data matrix; and

transforming the equalized data matrix into a data frame with N² data symbols, wherein each of the N² elements carries information corresponding to all N² data symbols.

21. The method of claim 20, wherein the equalization operation comprises a linear equalization operation.

22. The method of claim 20, wherein the equalization operation comprises a decision feedback least means square (DF-LMS) equalization operation.

23. The method of claim 20, further comprising:

transmitting, based on the equalization operation, a feedback signal that corresponds to a wireless channel.

24. The method of claim 23, wherein at least one of the N OTFS signals experiences an echo reflection in the wireless channel, and wherein the feedback signal comprises an indication of an anti-echo cancellation waveform.

25. The method of claim 23, wherein at least one of the N OTFS signals experiences a frequency shift in the wireless channel, and wherein the feedback signal comprises an indication of a compensatory reverse frequency shift.

26. A device for wireless communication, comprising:

a processor; and

a memory that comprises instructions stored thereupon, wherein the instructions when executed by the processor configure the processor to;

transform a data frame with N² data symbols into a time frequency shifted (TFS) data matrix with N² elements, wherein each of the N² elements carries information corresponding to all N² data symbols;

generate, based on a feedback signal, a pre-equalized TFS data matrix by performing a pre-equalization operation on the TFS data matrix;

generate N composite waveforms based on modulating each column of the pre-equalized TFS data matrix; and

transmit each of the N composite waveforms as a pre-equalized orthonormal time frequency space (OTFS) signal.

27. The device of claim 26, wherein the processor is further configured, as part of the modulating a column of the pre-equalized TFS data matrix, to:

separate each element of the column into real and imaginary components;

filter the real and imaginary components to generate filtered real and imaginary components; and

control, using the filtered real and imaginary components, an operation of a cosine and sine generator, respectively.

28. The device of claim 26, wherein the N composite waveforms comprise N² summation-symbol-weighted cyclically time shifted and cyclically frequency shifted waveforms.

29. The device of claim 26, wherein the processor is further configured, as part of the generating the pre-equalized TFS data matrix, to:

receive the feedback signal;

generate, based on the feedback signal, a pre-distortion transfer function that corresponds to a wireless channel; and

configure, based on the pre-distortion transfer function, the pre-equalization operation.

30. The device of claim 29, wherein the wireless channel comprises an echo reflection, and wherein the pre-equalization operation comprises an anti-echo cancellation waveform.

31. The device of claim 29, wherein the wireless channel comprises a frequency shift, and wherein the pre-equalization operation comprises a compensatory reverse frequency shift.

32. The device of claim 26, wherein the transmitting each of the N composite waveforms comprises transmitting over a plurality of time blocks or a plurality of frequency blocks.