Adjacent channel interference cancellation in multi-channel systems

• US 10,044,490 B2
• Filed: 11/14/2014
• Issued: 08/07/2018
• Est. Priority Date: 11/14/2013
• Status: Active Grant

• Current Assignee: Parallel Wireless, Inc.
• Original Assignee: Parallel Wireless, Inc.
• Inventors: Navalekar, Abhijit, Mishra, Rajesh Kumar, Garg, Sumit
• Primary Examiner(s): LAM, YEE F
• Application Number:
  US14/542,544
• Publication Number:
  US 20150131493A1
• Time in Patent Office: 1,362 Days
• CPC Class Codes: H04L 5/14 Two-way operation using the same type of signal, i.e. duplex

Abstract

A method for adjacent channel interference cancellation may be disclosed, comprising collecting adjacent channel usage samples at a first time; assigning coefficient weights in an adjacent channel interference model based on the adjacent channel usage samples; determining whether a radio may be available for measuring current adjacent channel usage; adjusting coefficient weights based on the current adjacent channel usage; and canceling noise in an adjacent channel at a second time based on the coefficient weights. A radio frequency chain may be coupled to the output of the radio transceiver and configured to sample adjacent channel interference caused by the radio transceiver.

Claims

1. A method for a base station to perform adjacent channel interference cancellation with multiple co-located transmit channels and multiple co-located receive channels, comprising:

determining, at a cloud coordination server, that a first transmit channel transceiver of the base station is scheduled to transmit when a second transmit channel transceiver of the base station is scheduled to receive, and initiating sending an interference cancellation procedure message based on said determination;

collecting, at the base station, a first channel usage sample at a first transmit time and at the first transmit channel transceiver using a first transmit channel;

collecting, at the base station, a second channel usage sample at the first transmit time and at the second transmit channel transceiver colocated with the first transmit channel transceiver-and using a second transmit channel;

sending the first channel usage sample and the second usage sample to the cloud coordination server for analysis using a low-latency connection;

assigning, by the cloud coordination server, coefficient weights in an adjacent channel interference model for each of the first and the second transmit channel based on the first and the second channel usage samples;

determining, at the base station, whether a radio is available for measuring current adjacent channel usage;

dynamically adjusting, by the cloud coordination server, coefficient weights for the first transmit channel based on the current adjacent channel usage; and

adding, at the base station, a correction signal canceling noise in a second receive channel at a second time based on the coefficient weights for the first transmit channel,

wherein the second transmit channel is adjacent to the first transmit channel, such that the second transmit channel shares an upper or a lower frequency boundary with a frequency band of the first transmit channel.

2. The method of claim 1, wherein canceling interference is performed in a digital domain and in an analog domain.

3. The method of claim 1, wherein the first time is more than 5 milliseconds prior to the second time.

4. The method of claim 1, further comprising determining whether the radio is available for measuring current adjacent channel usage based on an unused time slot in a time division duplexing scheme.

5. The method of claim 1, wherein the first and the second transmit channel are configured for use with a non-simultaneous access protocol.

6. The method of claim 1, wherein either the first or the second transmit channel is configured for use with a radio access technology that does not transmit cell-specific training signals.

7. The method of claim 1, wherein either the first or the second transmit channel is configured for use with Wi-Fi.

8. The method of claim 1, further comprising using unique pilots/preambles, a time division duplexing method, or a frequency division duplexing method wherein frame staggering is applied to the start time of frames.

9. The method of claim 1, further comprising performing, at the cloud coordination server, analysis of samples received from a plurality of transceivers.

10. The method of claim 1, further comprising assigning the coefficient weights at the base station, and dynamically adjusting the coefficient weights at the base station.

11. A multi-radio access technology (multi-RAT) base station, comprising:

a memory configured to store instructions;

a first transmit channel transceiver, the first transmit channel transceiver being configurable for receiving radio transmissions on a plurality of frequencies and for obtaining an adjacent channel interference signal sample;

a second transmit channel transceiver;

a network interface in communication with a cloud communication server, the cloud communication server configured to determine that the first transmit channel transceiver is scheduled to transmit when the second transmit channel transceiver is scheduled to receive, and configured to send an interference cancellation procedure message to the network interface based on said determination; and

a processor coupled to the memory, the first transmit channel transceiver, the second transmit channel transceiver, and a radio frequency chain configured to compute an adjacent channel interference cancellation signal based on the adjacent channel interference signal sample by;

collecting a first channel usage sample at a first transmit time and at the first transmit channel transceiver using a first transmit channel;

collecting a second channel usage sample at the first transmit time and at the second transmit channel transceiver using a second transmit channel;

sending the first channel usage sample and the second channel usage sample to the cloud coordination server for analysis using a low-latency connection;

receiving, from the cloud coordination server, coefficient weights in an adjacent channel interference model for each of the first and the second transmit channel based on the first and the second channel usage samples;

determining whether a radio is available for measuring current adjacent channel usage;

receiving, from the cloud coordination server, dynamically adjusted coefficient weights for the first transmit channel based on the current adjacent channel usage; and

adding a correction signal for canceling noise in a second receive channel at a second time based on the coefficient weights for the first transmit channel,

wherein the second transmit channel is adjacent to the first transmit channel, such that the second transmit channel is located immediately on either side of a frequency band of the first transmit channel.

12. The multi-RAT base station of claim 11, further comprising the radio frequency chain coupled to an output of the first transmit channel transceiver and configured to sample adjacent channel interference caused by the first transmit channel transceiver.

13. The multi-RAT base station of claim 12, wherein the radio frequency chain is configured to perform noise cancellation in an analog domain.

14. The multi-RAT base station of claim 11, further comprising a storage module for storing adjacent channel samples, and the processor further configured to precompute a plurality of coefficients for multiplying the adjacent channel interference cancellation signal based on the stored adjacent channel samples.

15. The multi-RAT base station of claim 11, wherein the radio transceiver is a software-defined radio.

16. A system for canceling adjacent channel interference, comprising:

a multi-radio access technology (multi-RAT) base station, the multi-RAT base station further comprising;

a memory configured to store instructions,

a first transmit channel transceiver, the first transmit channel transceiver configured to receive radio transmissions on a first transmission channel and to obtain a sample of an adjacent channel interference signal,

a second transmit channel transceiver, the second transmit channel transceiver configured to receive radio transmissions on a second transmission channel, and

a processor coupled to the memory, the first transmit channel transceiver, and the second transmit channel transceiver, and configured to;

send a first channel usage sample and a second channel usage sample to a cloud coordination server for analysis using a low-latency connection, and

add a correction signal for canceling noise in the second transmission channel based on coefficient weights received from the cloud coordination server for the first transmission channel,

thereby computing an adjacent channel interference cancellation signal based on the sample of the adjacent channel interference signal; and

the cloud coordination server, the cloud coordination server further comprising;

a processor in communication with the multi-RAT base station for determining that a first transmit channel transceiver of the multi-RAT base station is scheduled to transmit when a second transmit channel transceiver of the multi-RAT base station is scheduled to receive, and for sending an interference cancellation procedure message to the multi-RAT base station based on said determination; and

an interference cancellation module configured to;

receive the sample of the adjacent channel interference signal from the multi-RAT base station,

assign coefficient weights in the adjacent channel interference signal, and

dynamically adjust the coefficient weights for the first transmission channel based on a current adjacent channel usage,

wherein the adjacent channel interference signal is in a channel that is adjacent to the first transmission channel, such that the adjacent channel interference signal is in a channel located immediately on either side of a frequency band of the first transmission channel.

17. The system of claim 16, wherein the interference cancellation module is configured to use a neural network to determine the coefficient weights.

18. The system of claim 16, wherein the interference cancellation module is configured to use samples from more than one multi-RAT base station to determine the coefficient weights.

19. The system of claim 16, wherein the multi-RAT base station is configured to receive the determined coefficient weights from the coordination server and is configured to apply the adjacent channel interference cancellation signal based on the determined coefficient weights.