Multiple access using orthogonal time frequency space modulation

Patent metadata

Field	Value
Publication number	US-11070329-B2
Application number	US-201615758322-A
Country	US
Kind code	B2
Filing date	Sep 7, 2016
Priority date	Sep 7, 2015
Publication date	Jul 20, 2021
Grant date	Jul 20, 2021

Abstract

An Orthogonal Time Frequency Space Modulation (OTFS) modulation scheme achieving multiple access by multiplexing multiple signals at the transmitter-side performs allocation of transmission resources to a first signal and a second signal, combining and converting to a transmission format via OTFS modulation and transmitting the signal over a communication channel. At the receiver, multiplexed signals are recovered using orthogonality property of the basis functions used for the multiplexing at the transmitter.

First claim

The invention claimed is:

1. A method of transmitting over a digital communications channel, the method implemented at a transmitter-side, comprising:
allocating, to a first signal for a first user equipment a first group of transmission resources from a delay-Doppler plane, which is represented by a first and a second orthogonal axes corresponding to a first transmission dimension and a second transmission dimension, respectively, for transmission;
allocating, to a second signal for a second user equipment, a second group of transmission resources from the delay-Doppler plane for transmission;
transforming, using a first two-dimensional transform, a multiplexing of the first signal having the first group of transmission resources and the second signal having the second group of transmission resources from the delay-Doppler plane to a corresponding transformed signal in a time-frequency plane represented by a third and a fourth orthogonal axes corresponding to a third transmission dimension and a fourth transmission dimension, respectively;
converting the transformed signal to a formatted signal according to a transmission format of the digital communications channel; and
transmitting the formatted signal over the digital communications channel,
wherein transmission resources used by the first signal and the second signal are non-overlapping in the delay-Doppler plane.

2. The method of claim 1 , wherein the first signal comprises a first information signal for a first user equipment and wherein the second signal comprises a second information signal for a second user equipment.

3. The method of claim 1 , wherein the operation of converting the transformed signal to the formatted signal includes applying a multicarrier modulation scheme to the transformed signal.

4. The method of claim 3 , wherein the multicarrier modulation scheme is an orthogonal frequency division multiplexing (OFDM) scheme.

5. The method of claim 4 , wherein the transmission format comprises a Long Term Evolution (LTE) transmission format and wherein the OFDM scheme produces a signal compatible with the LTE transmission format.

6. The method of claim 2 , wherein the allocating the first group of transmission resources comprises allocating a first set of basis functions and the allocating the second group of transmission resources comprises allocating a second set of basis functions that is orthogonal to the first set of basis functions.

7. The method of claim 1 , further including:
assigning a first resource window to the first signal; and
assigning a second resource window to the second signal, wherein the second resource is orthogonal to the first window and orthogonal to time and/or frequency shifted versions of the second window.

8. The method of claim 1 , wherein the allocating the first group of transmission resources and the allocating the second group of transmission resources comprises allocating different antenna resources to the first group and the second group.

9. The method of claim 8 , wherein the allocating the first group of transmission resources and the allocating the second group of transmission resources comprises performing spatial multiplexing by using a same set of basis functions for both the first group and the second group.

10. The method of claim 1 , further comprising:
allocating, to at least one more additional signal, an additional group of transmission resources from the delay-Doppler plane logical for transmission; and
including in the multiplexing, prior to the transforming operation, the at least one more additional signal, wherein transmission resources used by the at least one more additional signal are non-overlapping with transmission resources used by the first signal and the second signal in the delay-Doppler plane and the time-frequency plane.

11. The method of claim 1 , wherein the operation of converting the transform signal to the formatted signal includes:
code division multiplexing the transformed signal using a two-dimensional code to generate a code-division multiplexed signal; and
performing a multicarrier modulation operation on the code-division multiplexed signal.

12. The method of claim 1 , wherein the operation of converting the transform signal to the formatted signal includes:
randomizing phases of the transformed signal to generate a phase-randomized signal; and
performing a multicarrier modulation operation on the phase-randomized signal.

13. The method of claim 1 , wherein the second signal is a pilot signal, and wherein the allocating the second group of resources includes allocating the second group of resources as a function of an identity of a cell in which the transmitter-side is operating.

14. A signal transmission method over a digital communications channel, implemented at a transmitter-side, comprising:
allocating, to a first signal, a first group of transmission resources from a delay-Doppler plane, which is represented by a first and a second orthogonal axes corresponding to a first transmission dimension an a second transmission dimension, respectively, for transmission;
transforming, using a first two-dimensional transform, the first signal having the first group of transmission resources from the delay-Doppler plane to a corresponding transformed signal in a time-frequency plane represented by a third and a fourth orthogonal axes corresponding to a third transmission dimension and a fourth transmission dimension respectively;
converting the transformed signal to a formatted signal according to a transmission format of the digital communications channel; and
transmitting the formatted signal over the digital communications channel.

15. The method of claim 14 , wherein the operation of converting the transformed signal to the formatted signal includes applying a multicarrier modulation scheme to the transformed signal.

16. The method of claim 15 , wherein the multicarrier modulation scheme is an orthogonal frequency division multiplexing (OFDM) scheme.

17. The method of claim 16 , wherein the transmission format comprises a Long Term Evolution (LTE) transmission format and wherein the OFDM scheme produces a signal compatible with the LTE transmission format.

18. The method of claim 14 , further including:
allocating, to at least one additional second signal, a second group of resources from the delay-Doppler plane for transmission, wherein transmission resources used by the first signal and the at least one additional second signal are non-overlapping in at least one of the delay-Doppler plane and the time-frequency plane.

19. The method of claim 18 , wherein the first signal comprises a first information signal for a first user equipment and wherein the at least one additional second signal comprises a second information signal for a second user equipment.

20. The method of claim 18 , wherein the first signal comprises an information signal for a user equipment and the at least one additional second signal comprises a reference signal.

21. The method of claim 14 , wherein the first signal comprises a pilot signal.

22. An apparatus, comprising:
a memory configured to store a method for transmitting over a digital communications channel; and
a processor, wherein the processor is configured to implement the method, the method comprising:
allocating, to a first signal for a first user equipment a first group of transmission resources from a delay-Doppler plane, which is represented by a first and a second orthogonal axe

Assignees

• Cohere Tech Inc

Inventors

• Hadani Ronny
• Monk Anton
• Rakib Shlomo Selim
• Tsatsanis Michail

Classifications

• H04L5/0048

  Allocation of pilot signals, i.e. of signals known to the receiver (allocation of control signalling H04L5/0053; use of control signalling H04L5/0091) · CPC title

• H04L5/0007 Primary

  the frequencies being orthogonal, e.g. OFDM(A) or DMT · CPC title

• H04L1/0023 Primary

  characterised by the signalling · CPC title

• H04L5/0023 Primary

  Time-frequency-space · CPC title

• H04B7/06

  at the transmitting station · CPC title