MIMO (multiple-input, multiple-output) inter-stream interference cancellation

Patent metadata

Field	Value
Publication number	US-10644766-B2
Application number	US-201816110397-A
Country	US
Kind code	B2
Filing date	Aug 23, 2018
Priority date	Dec 23, 2016
Publication date	May 5, 2020
Grant date	May 5, 2020

Abstract

Apparatuses, methods, and systems for MIMO inter-stream interference cancellation are disclosed. One method includes determining a channel matrix between a plurality of transmitting antennas of a transmitter and a plurality of receiving antennas of a receiver, determining a plurality of channel propagation delays based on a propagation delay between each of the plurality of transmitting antennas and each of the plurality of receiving antennas, determining differences in the plurality of channel propagation delays, preprocessing, by the transmitter, streams of symbols for each transmitting antenna for transmission based on the differences in the plurality of channel propagation delays and based on the channel matrix, and transmitting, by the transmitter, the preprocessed symbol streams through the plurality of transmitting antennas.

First claim

What is claimed:

1. A method, comprising:
determining a channel matrix between a plurality of transmitting antennas of a transmitter and a plurality of receiving antennas of a receiver;
determining a plurality of channel propagation delays based on a propagation delay between each of the plurality of transmitting antennas and each of the plurality of receiving antennas;
preprocessing, by the transmitter, streams of symbols for each transmitting antenna for transmission based on the plurality of channel propagation delays and based on the channel matrix, wherein the preprocessing comprises, for a symbol stream of each transmitting antenna, linearly combining a scaled version of the symbol stream with a scaled and delayed version of one or more symbol streams of other of the plurality of transmitting antennas; and
transmitting, by the transmitter, the preprocessed symbol streams through the plurality of transmitting antennas.

2. The method of claim 1 , wherein a difference in a propagation delay between a first transmitting antenna and a first receiving antenna and a second transmitting antenna and the first receiving antenna is greater than multiple time durations of a symbol in the streams of symbols.

3. The method of claim 1 , wherein the scaled version of the symbol stream and the scaled version of the symbol streams of other of the plurality of transmitting antennas are determined based on a precoding matrix, wherein the precoding matrix is determined based on the channel matrix.

4. The method of claim 3 , wherein the precoding matrix is determined based on the channel matrix and a selected precoding function.

5. The method of claim 1 , further comprising:
independently receiving symbol streams at each of the receiving antennas.

6. The method of claim 1 , further comprising continually estimating a location of one or more of the transmitting antennas, and updating values of the plurality of channel propagation delays based on the estimated location of the one or more transmitting antennas.

7. The method of claim 1 , further comprising continually updating values of the plurality of propagation delays, wherein continually updating comprises transmitting a signal from at least one of the transmitting antennas and correlating versions of signals received at the plurality of receiving antennas.

8. The method of claim 1 , wherein the plurality of transmitting antennas is located on a flying drone which circles a center point.

9. The method of claim 1 , wherein the plurality of transmitting antennas is located on a satellite.

10. A method, comprising:
determining a channel matrix between a plurality of transmitting antennas of a transmitter and a plurality of receiving antennas of a receiver;
determining a plurality of channel propagation delays based on a propagation delay between each of the plurality of transmitting antennas and each of the plurality of receiving antennas;
receiving, through the channel, streams of symbols through each of the plurality of receiving antennas; and
processing, by the receiver, the streams of symbols for each receiving antenna based on the plurality of channel propagation delays and based on the channel matrix, wherein the processing comprises, for a symbol stream of each transmitting antenna, linearly combining a scaled version of the symbol stream with a scaled and delayed version of one or more symbol streams of other of the plurality of transmitting antennas.

11. The method of claim 10 , wherein a difference in a propagation delay between a first transmitting antenna and a first receiving antenna and a second transmitting antenna and the first receiving antenna is greater than multiple time durations of a symbol in the streams of symbols.

12. The method of claim 10 , wherein the scaled version of the symbol stream and the scaled version of the symbol streams of other of the plurality of receiving antennas are determined based on a precoding matrix, wherein the precoding matrix is determined based on the channel matrix.

13. The method of claim 10 , further comprising continually estimating a location of one or more of the transmitting antennas, and updating values of the plurality of channel propagation delays based on the estimated location of the one or more transmitting antennas.

14. The method of claim 10 , further comprising continually updating values of the plurality of propagation delays, wherein continually updating comprises transmitting a signal from at least one of the transmitting antennas and correlating versions of signals received at the plurality of receiving antennas.

15. The method of claim 10 , wherein the plurality of transmitting antennas is located on a flying drone which circles a center point.

16. The method of claim 10 , wherein the plurality of transmitting antennas is located on a satellite.

17. A transmitter, comprising:
a plurality of radio frequency (RF) chains, wherein the plurality of RF chains is connected to a plurality of transmitting antennas;
a controller, the controller operative to:
determine a channel matrix between the plurality of transmitting antennas and a plurality of receiving antennas of a receiver;
determine a plurality of channel propagation delays based on a propagation delay between each of the plurality of transmitting antennas and each of the plurality of receiving antennas;
preprocess a stream of symbols for each transmitting antenna for transmission based on the plurality of channel propagation delays and based on the channel matrix, wherein the preprocessing comprises, for a symbol stream of each transmitting antenna, linearly combining a scaled version of the symbol stream with a scaled and delayed version of one or more symbol streams of other of the plurality of transmitting antennas; and
transmit the preprocessed symbol streams through the plurality of transmitting antennas.

Assignees

• Facebook Inc

Inventors

• Qu Qi
• Alex Sam Padinjaremannil
• Yazdan Ali
• Tiwari Abhishek
• Yan Yan
• Zhou Hongyu
• Bondalapati Pratheep

Classifications

• H04B7/08

  at the receiving station · CPC title

• H04B7/0456 Primary

  Selection of precoding matrices or codebooks, e.g. using matrices antenna weighting · CPC title

• H04B7/06

  at the transmitting station · CPC title

• H01Q1/288

  Satellite antennas · CPC title

• H01Q21/28

  Combinations of substantially independent non-interacting antenna units or systems {(multiple beam H01Q25/00)} · CPC title