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

• US 20140169433A1
• Filed: 06/25/2013
• Published: 06/19/2014
• Est. Priority Date: 05/26/2011
• Status: Active Grant

• Current Assignee: Cohere Technologies Inc
• Original Assignee: Cohere Technologies Inc
• Inventors: Hadani, Ronny, Rakib, Salim Shlomo
• Granted Patent: US 8,976,851 B2
• Time in Patent Office: Days
• US Class Current: 375/229
• CPC Class Codes: H04B 3/237 using two adaptive filters, e.g. for near end and for end echo cancelling
• CPC Class Codes: H04L 23/02 adapted for orthogonal signalling
• CPC Class Codes: H04L 25/03834 using pulse shaping
• CPC Class Codes: H04L 27/2636 with FFT or DFT modulators, e.g. standard single-carrier frequency-division multiple access [SC-FDMA] transmitter or DFT spread orthogonal frequency division multiplexing [DFT-SOFDM]
• CPC Class Codes: H04L 27/2655 Synchronisation arrangements
• CPC Class Codes: H04L 27/2657 Carrier synchronisation
• CPC Class Codes: H04L 27/2697 in combination with other modulation techniques
• CPC Class Codes: H04L 5/0016 Time-frequency-code
• CPC Class Codes: H04L 5/0044 allocation of payload
• CPC Class Codes: H04L 5/0048 Allocation of pilot signals, i.e. of signals known to the receiver
• CPC Class Codes: H04L 5/14 Two-way operation using the same type of signal, i.e. duplex

Abstract

A method which includes receiving a first modulated signal from a first user device, the first modulated signal being generated based upon a time-frequency transformation of first user data. The method further includes receiving a second modulated signal from a second user device, the second modulated signal being generated based upon a time-frequency transformation of second user data. The first modulated signal and the second modulated signal are then processed.

Claims

1. A method, comprising:

receiving a first modulated signal from a first user device, the first modulated signal being generated based upon a time-frequency transformation of first user data;

receiving a second modulated signal from a second user device, the second modulated signal being generated based upon a time-frequency transformation of second user data; and

processing the first modulated signal and the second modulated signal.

2. The method of claim 1 wherein the first user data is associated with a first transmission interval of an orthonormal time frequency shifting (OTFS) transmission matrix having dimensions of time and frequency and the and second user data is associated with a different transmission interval of the OTFS transmission matrix.

3. The method of claim 1 wherein the first user data is associated with a first frequency band of an orthonormal time frequency shifting (OTFS) transmission matrix having dimensions of time and frequency and the and second user data is associated with a different frequency band of the OTFS transmission matrix.

4. The method of claim 1 wherein the first user data is associated with a first area of an orthonormal time frequency shifting (OTFS) transmission matrix having dimensions of time and frequency, and the and second user data is associated with a second area of the OTFS transmission matrix.

5. A method for echo cancellation, comprising:

developing a time-frequency model of an echo channel between a transmit antenna and a receive antenna; and

generating, based upon the time-frequency model, an echo cancellation signal.

6. A method for full-duplex communication, the method comprising:

transmitting, from a transmit antenna and within a frequency band, a transmit signal;

receiving, at a receive antenna, a receive signal within the frequency band; and

correcting the receive signal in accordance with a time-frequency representation of a communication channel between the transmit antenna and the receive antenna.

7. A method, comprising:

receiving a set of M time-frequency representations of signal energy received by a set of M antennas of a receiver, the signal energy being received in response to information signals transmitted by a set of N transmit antennas of a transmitter wherein each of the information signals is generated using a time-frequency transformation; and

generating estimates of the information signals based upon the M time-frequency representations, where M is greater than N.

8. The method of claim 7 wherein each of the information signals is generated in accordance with a time-frequency shifting matrix.

9. A method of signal separation, the method comprising:

receiving, at a receiver, first information signals within a first frequency band wherein the first information signals are modulated in accordance with a first data matrix encoded using a first basis matrix;

receiving, at the receiver, second information signals within the first frequency band wherein the second information signals are modulated in accordance with a second data matrix encoded using a second basis matrix different from the first basis matrix; and

generating estimates of elements of the first data matrix and elements of the second data matrix based upon the first information signals and the second information signals.

10. A method, comprising:

receiving a time resolution control signal;

transforming a first original data frame in accordance with a first time-frequency transformation so as to provide a first transformed data matrix wherein the first time-frequency transformation is selected in accordance with the time resolution control signal; and

generating a first modulated signal in accordance with elements of the first transformed data matrix.

11. The method of claim 10 further including:

receiving a Doppler resolution control signal;

transforming a second original data frame in accordance with a second time-frequency transformation so as to provide a second transformed data matrix wherein the second time-frequency transformation is selected in accordance with the Doppler resolution control signal; and

generating a second modulated signal in accordance with elements of the second transformed data matrix.

12. The method of claim 10 further including:

receiving an additional time resolution control signal;

transforming a second original data frame in accordance with a second time-frequency transformation so as to provide a second transformed data matrix wherein the second time-frequency transformation is selected in accordance with the additional time resolution control signal; and

generating a second modulated signal in accordance with elements of the second transformed data matrix.

13. A method, comprising:

receiving a Doppler resolution control signal;

transforming a first original data frame in accordance with a first time-frequency transformation so as to provide a first transformed data matrix wherein the first time-frequency transformation is selected in accordance with the Doppler resolution control signal; and

generating a first modulated signal in accordance with elements of the first transformed data matrix.

14. The method of claim 13 further including:

receiving a time resolution control signal;

transforming a second original data frame in accordance with a second time-frequency transformation so as to provide a second transformed data matrix wherein the second time-frequency transformation is selected in accordance with the time resolution control signal; and

generating a second modulated signal in accordance with elements of the second transformed data matrix.

15. A method of variable latency data transmission, the method comprising:

transforming a first original data frame in accordance with a first time-frequency transformation so as to provide a first transformed data matrix wherein the first time-frequency transformation is associated with a first latency;

transforming a second original data frame in accordance with a second time-frequency transformation so as to provide a second transformed data matrix wherein the second time-frequency transformation is associated with a second latency; and

transmitting elements of the first transformed data matrix over a first frame period corresponding to the first latency and transmitting elements of the second transformed data matrix over a second frame period corresponding to the second latency wherein the first frame period is different from the second frame period.