Orthogonal time frequency space communication system compatible with OFDM

• US 10,404,514 B2
• Filed: 06/27/2016
• Issued: 09/03/2019
• Est. Priority Date: 06/27/2015
• Status: Active Grant

• Current Assignee: Cohere Technologies Inc
• Original Assignee: Cohere Technologies Inc
• Inventors: Rakib, Shlomo Selim, Hadani, Ronny
• Primary Examiner(s): Lee, Siu M
• Application Number:
  US15/740,316
• Publication Number:
  US 20180227159A1
• Time in Patent Office: 1,163 Days
• CPC Class Codes: G06F 17/147 Discrete orthonormal transforms, e.g. discrete cosine transform, discrete sine transform, and variations therefrom, e.g. modified discrete cosine transform, integer transforms approximating the discrete cosine transform G06F17/145 takes precedence
• CPC Class Codes: H04L 1/06 using space diversity
• CPC Class Codes: H04L 27/26 Systems using multi-frequency codes 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 27/2646 using feedback from receiver for adjusting OFDM transmission parameters, e.g. transmission timing or guard interval length
• CPC Class Codes: H04L 5/0023 Time-frequency-space

Abstract

A system and method for orthogonal time frequency space communication and waveform generation. The method includes receiving a plurality of information symbols and encoding an N×M array containing the plurality of information symbols into a two-dimensional array of modulation symbols by spreading each of the plurality of information symbols with respect to both time and frequency. The two-dimensional array of modulation symbols is then transmitted using M mutually orthogonal waveforms included within M frequency sub-bands.

Claims

1. A method of receiving a modulated signal, the method comprising:

receiving a plurality of signal components of the modulated signal;

generating, by performing an OFDM demodulation operation using the plurality of signal components, a plane of estimated time-frequency modulation symbols; and

providing an estimated data frame by performing an inverse of a two dimensional time-frequency transformation with respect to the plane of estimated time-frequency modulation symbols,

wherein the performing the inverse of the two dimensional time-frequency transformation includes performing a windowing operation and a symplectic Fourier transform; and

wherein the windowing operation either uses a window that is matched to a transmitter-side window, selected to randomize phases of symbols in the modulated signal, or uses a 2D window function.

2. The method of claim 1, wherein the windowing operation uses a window that is matched to a transmitter-side window.

3. The method of claim 1, wherein the windowing operation is selected to randomize phases of symbols in the modulated signal.

4. The method of claim 1, wherein the windowing operation uses a 2D window function.

5. A method of receiving a modulated signal, the method comprising:

receiving a plurality of signal components of the modulated signal;

generating, by performing a Multicarrier Filter Bank (MCFB) demodulation operation using the plurality of signal components, a plane of estimated time-frequency modulation symbols; and

providing an estimated data frame by performing an inverse of a two dimensional time-frequency transformation with respect to the plane of estimated time-frequency modulation symbols, wherein the performing the inverse of the two dimensional time-frequency transformation includes performing a windowing operation and a symplectic Fourier transform.

6. The method of claim 5, wherein the windowing operation uses a window that is matched to a transmitter-side window.

7. The method of claim 5, wherein the windowing operation is selected to randomize phases of symbols in the modulated signal.

8. The method of claim 5, wherein the windowing operation uses a 2D window function.

9. A receiver apparatus, the apparatus comprising:

a receiver front end, the receiver front end being configured to receive a plurality of signal components of a modulated signal;

an OFDM demodulator configured to generate a plane of estimated time-frequency modulation symbols based upon the plurality of signal components; and

an Orthogonal Time Frequency Space (OTFS) post-processing unit operative to provide an estimated data frame, the OTFS post-processing unit performing an inverse of a two dimensional time-frequency transformation with respect to the plane of estimated time-frequency modulation symbols;

wherein the inverse of the two dimensional time-frequency transformation comprises a windowing operation and a symplectic Fourier transform; and

wherein the windowing operation either uses a window that is matched to a transmitter-side window, selected to randomize phases of symbols in the modulated signal, or uses a 2D window function.

10. The apparatus of claim 9, wherein the windowing operation uses a window that is matched to a transmitter-side window.

11. The apparatus of claim 9, wherein the windowing operation is selected to randomize phases of symbols in the modulated signal.

12. The apparatus of claim 9, wherein the windowing operation uses a 2D window function.

13. The apparatus of claim 9, wherein the apparatus is included in a cell phone.

14. A receiver apparatus, the apparatus comprising:

a receiver front end, the receiver front end being configured to receive a plurality of signal components of a modulated signal;

a MCFB demodulator configured to generate a plane of estimated time-frequency modulation symbols based upon the plurality of signal components; and

an OTFS post-processing unit operative to provide an estimated data frame, the OTFS post-processing unit performing an inverse of a two dimensional time-frequency transformation with respect to the plane of estimated time-frequency modulation symbols;

wherein the inverse of the two dimensional time-frequency transformation comprises a windowing operation and a symplectic Fourier transform.

15. The apparatus of claim 14, wherein the windowing operation uses a window that is matched to a transmitter-side window.

16. The apparatus of claim 14, wherein the windowing operation is selected to randomize phases of symbols in the modulated signal.

17. The apparatus of claim 14, wherein the windowing operation uses a 2D window function.

18. The apparatus of claim 14, wherein the apparatus is included in a cell phone.