Co-channel interference cancellation method and apparatus

• US 10,440,720 B2
• Filed: 04/26/2018
• Issued: 10/08/2019
• Est. Priority Date: 10/27/2015
• Status: Active Grant

• Current Assignee: Huawei Technologies Co., Ltd. (Huawei Investment & Holding Co., Ltd.)
• Original Assignee: Huawei Technologies Co., Ltd. (Huawei Investment & Holding Co., Ltd.)
• Inventors: Liu, Qiao, Li, Xiaodong
• Primary Examiner(s): Le, Nhan T
• Application Number:
  US15/963,672
• Publication Number:
  US 20180249472A1
• Time in Patent Office: 530 Days
• CPC Class Codes: H04B 1/1081 Reduction of multipath noise by equalising H04B7/005
• CPC Class Codes: H04B 1/123 using adaptive balancing or compensation means adaptive filter circuits and algorithms H03H
• CPC Class Codes: H04B 1/525 with means for reducing leakage of transmitter signal into the receiver
• CPC Class Codes: H04L 25/0204 of multiple channels
• CPC Class Codes: H04L 25/0328 with interference cancellation circuitry adaptations for interference cancellation within a sequence estimator H04L25/03305; interference related aspects of direct sequence spread spectrum H04B1/7097; interference related aspects of frequency hopping spread spectrum H04B1/715; see also H04B1/10
• CPC Class Codes: H04W 28/04 Error control
• CPC Class Codes: H04W 72/541 using the level of interference

Abstract

A co-channel interference cancellation method and apparatus are provided. The method includes: obtaining effective interference by filtering co-channel interference according to a preset interference strength threshold, and obtaining a plurality of effective interference subgroups by grouping the effective interference; obtaining a reference interference sub-signal corresponding to the effective interference subgroup, by delaying a reference interference signal according to a determined interference delay of each effective interference subgroup; after each reference interference sub-signal passes through a corresponding adaptive interference reconstruction filter, obtaining a reconstructed interference signal by overlaying each reference interference sub-signal; and performing a subtraction operation on a received signal and the reconstructed interference signal. In this way, spectrum consumption is greatly reduced, and implementation is simple.

Claims

1. A co-channel interference cancellation method, comprising:

obtaining effective interference by filtering co-channel interference according to a preset interference strength threshold, and obtaining a plurality of effective interference subgroups by grouping the effective interference;

obtaining a reference interference sub-signal corresponding to each effective interference subgroup, by delaying a reference interference signal according to a determined interference delay of each effective interference subgroup;

after each reference interference sub-signal passes through a corresponding adaptive interference reconstruction filter, obtaining a reconstructed interference signal by overlaying each reference interference sub-signal; and

obtaining a first wanted signal by performing a subtraction operation on a received signal and the reconstructed interference signal.

2. The method according to claim 1, wherein the obtaining the effective interference by filtering the co-channel interference according to the preset interference strength threshold comprises:

determining, as the effective interference, co-channel interference obtained after an interference strength value of first target interference in the co-channel interference is set to zero, wherein the first target interference is interference that is in the co-channel interference and whose interference strength value is less than or equal to the preset interference strength threshold.

3. The method according to claim 1, wherein before the obtaining the effective interference by filtering the co-channel interference according to the preset interference strength threshold, the method further comprises:

determining a reference delay of the co-channel interference, wherein the reference delay is a counting result from counting a first symbol that is used to send a preamble of the reference interference signal, until strongest interference with a maximum interference strength value is received, wherein

an interference delay of each effective interference subgroup is equal to a sum of a delay difference of each effective interference subgroup and the reference delay, and the delay difference of each effective interference subgroup is equal to a difference between a relative delay of each effective interference subgroup and a related delay of the strongest interference.

4. The method according to claim 2, wherein the obtaining the plurality of the effective interference subgroups by grouping the effective interference comprises:

determining second target interference in a target range interference as an effective interference subgroup, wherein the target range interference comprises all interference that is in the effective interference and that is started with current interference with an interference strength value greater than zero and ended with continuously appearing interference whose quantity is greater than a preset quantity and whose interference strength value is zero, and the second target interference is interference before the interference that is in the target range interference and whose quantity is greater than the preset quantity and whose interference strength value is zero; and

determining, as a next current interference, first interference that follows the target range interference and whose interference strength value is greater than zero, and performing the determination of the second target interference in the target range interference as the effective interference subgroup until the effective interference is grouped into the plurality of effective interference subgroups.

5. The method according to claim 1, further comprising:

obtaining a second wanted signal by performing a decision on the first wanted signal;

obtaining a difference between the first wanted signal and the second wanted signal; and

updating, according to the difference, a filter coefficient that is of the corresponding adaptive interference reconstruction filter and that corresponds to each reference interference sub-signal.

6. A non-transitory computer readable medium, comprising processor-executable instructions, which when executed by a processor causes the processor to implement operations including:

obtaining effective interference by filtering co-channel interference according to a preset interference strength threshold;

obtaining a plurality of effective interference subgroups by grouping the effective interference;

obtaining a reference interference sub-signal corresponding to each effective interference subgroup, by delaying a reference interference signal according to a determined interference delay of each effective interference subgroup;

after each reference interference sub-signal passes through a corresponding adaptive interference reconstruction filter, obtaining a reconstructed interference signal by overlaying each reference interference sub-signal; and

obtaining a first wanted signal by performing a subtraction operation on a received signal and the reconstructed interference signal.

7. The non-transitory computer readable medium according to claim 6, wherein the operation of obtaining the effective interference by filtering the co-channel interference according to the preset interference strength threshold includes:

determining, as the effective interference, co-channel interference obtained after an interference strength value of first target interference in the co-channel interference is set to zero, wherein the first target interference is interference that is in the co-channel interference and whose interference strength value is less than or equal to the preset interference strength threshold.

8. The non-transitory computer readable medium according to claim 6, wherein the operations further include:

determining a reference delay of the co-channel interference before obtaining the effective interference by filtering the co-channel interference according to the preset interference strength threshold, wherein the reference delay is a counting result from counting a first symbol that is used to send a preamble of the reference interference signal, until strongest interference with a maximum interference strength value is received, wherein

an interference delay of each effective interference subgroup is equal to a sum of a delay difference of each effective interference subgroup and the reference delay, and the delay difference of each effective interference subgroup is equal to a difference between a relative delay of each effective interference subgroup and a related delay of the strongest interference.

9. The non-transitory computer readable medium according to claim 7, wherein the operation of obtaining the plurality of effective interference subgroups by grouping the effective interference includes:

determining second target interference in a target range interference as an effective interference subgroup, wherein the target range interference comprises all interference that is in the effective interference and that is started with current interference with an interference strength value greater than zero and ended with continuously appearing interference whose quantity is greater than a preset quantity and whose interference strength value is zero, and the second target interference is interference before the interference that is in the target range interference and whose quantity is greater than the preset quantity and whose interference strength value is zero; and

determining, as a next current interference, first interference that follows the target range interference and whose interference strength value is greater than zero, and performing the determination of the second target interference in the target range interference as the effective interference subgroup until the effective interference is grouped into the plurality of effective interference subgroups.

10. The non-transitory computer readable medium according to claim 6, wherein the operation further includes:

obtaining a second wanted signal by performing a decision on the first wanted signal;

obtaining a difference between the first wanted signal and the second wanted signal; and

updating, according to the difference, a filter coefficient that is of the corresponding adaptive interference reconstruction filter and that corresponds to each reference interference sub-signal.

11. A co-channel interference cancellation apparatus, comprising a memory and a processor, wherein the memory stores a group of program code, and the processor is configured to execute the program code stored in the memory to perform the following operations:

obtaining effective interference by filtering co-channel interference according to a preset interference strength threshold, and obtaining a plurality of effective interference subgroups by grouping the effective interference;

obtaining a reference interference sub-signal corresponding to each effective interference subgroup, by delaying a reference interference signal according to a determined interference delay of each effective interference subgroup;

after each reference interference sub-signal passes through a corresponding adaptive interference reconstruction filter, obtaining a reconstructed interference signal by overlaying each reference interference sub-signal; and

obtaining a first wanted signal by performing a subtraction operation on a received signal and the reconstructed interference signal.

12. The apparatus according to claim 11, wherein the operation of obtaining the effective interference by filtering the co-channel interference according to the preset interference strength threshold includes:

determining, as the effective interference, co-channel interference obtained after an interference strength value of first target interference in the co-channel interference is set to zero, wherein the first target interference is interference that is in the co-channel interference and whose interference strength value is less than or equal to the preset interference strength threshold.

13. The apparatus according to claim 11, wherein before the processor obtains the effective interference by filtering the co-channel interference according to the preset interference strength threshold, the processor executes the program code stored in the memory to further perform the following operation:

determining a reference delay of the co-channel interference, wherein the reference delay is a counting result from counting a first symbol that is used to send a preamble of the reference interference signal, until strongest interference with a maximum interference strength value is received, wherein

an interference delay of each effective interference subgroup is equal to a sum of a delay difference of each effective interference subgroup and the reference delay, and the delay difference of each effective interference subgroup is equal to a difference between a relative delay of each effective interference subgroup and a related delay of the strongest interference.

14. The apparatus according to claim 12, wherein the operation of obtaining the plurality of effective interference subgroups by grouping the effective interference includes:

determining second target interference in a target range interference as an effective interference subgroup, wherein the target range interference comprises all interference that is in the effective interference and that is started with current interference with an interference strength value greater than zero and ended with continuously appearing interference whose quantity is greater than a preset quantity and whose interference strength value is zero, and the second target interference is interference before the interference that is in the target range interference and whose quantity is greater than the preset quantity and whose interference strength value is zero; and

determining, as a next current interference, first interference that follows the target range interference and whose interference strength value is greater than zero, and performing the determination of the second target interference in the target range interference as the effective interference subgroup until the effective interference is grouped into the plurality of effective interference subgroups.

15. The apparatus according to claim 11, wherein the processor executes the program code stored in the memory to further perform the following operations:

obtaining a second wanted signal by performing a decision on the first wanted signal;

obtaining a difference between the first wanted signal and the second wanted signal; and

updating, according to the difference, a filter coefficient that is of the corresponding adaptive interference reconstruction filter and that corresponds to each reference interference sub-signal.