# US 2019/0319731 A1 · Interference cancellation method and base station > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2019/0319731 A1 - Document ID: US20190319731A1 - Status: Published application - Kind: A1 - Application number: 16/453,830 - Filed: 2019-06-26 - Published: 2019-10-17 - Earliest claimed: 2016-12-29 - Assignees: Huawei Technologies Co., Ltd. - Applicants: Huawei Technologies Co., Ltd. - Inventors: Taofu Mo; Bo Han - Web page: https://patentgrep.com/patent/US20190319731A1 ## CPC - H04J 11/0056: {Inter-base station aspects} - H04B 7/024: Co-operative use of antennas of several sites, e.g. in co-ordinated multipoint or co-operative multiple-input multiple-output [MIMO] systems - H04B 7/0413: MIMO systems - H04B 7/063: {Parameters other than those covered in groups H04B7/0623 - H04B7/0634, e.g. channel matrix rank or transmit mode selection} - H04L 5/0051: {of dedicated pilots, i.e. pilots destined for a single user or terminal} - H04L 5/0073: {Allocation arrangements that take into account other cell interferences} - H04L 5/1423: {for simultaneous baseband signals} - H04L 27/2691: {involving interference determination or cancellation} - H04J: MULTIPLEX COMMUNICATION (transmission in general H04B; peculiar to transmission of digital information H04L5/00; systems for the simultaneous or sequential transmission of more than one television signal H04N7/08; in exchanges H04Q11/00; stereophonic systems H04S) - H04B: TRANSMISSION - H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M) ## Abstract Embodiments of this application disclose an interference cancellation method and a base station. The method in the embodiments of this application may include obtaining, by a first base station, system information of a neighboring cell. The method may also include determining, by the first base station, interference channel information of a second base station to the first base station based on the system information, where the second base station is a base station in a coverage area of the neighboring cell. Furthermore, the method may also include receiving, by the first base station based on the interference channel information, an uplink signal sent by user equipment in a coverage area of the first base station. ## Claims ### Claim 1 An interference cancellation method, comprising: obtaining, by a first base station, system information of a neighboring cell; determining, by the first base station, interference channel information of a second base station to the first base station based on the system information, wherein the second base station is a base station in a coverage area of the neighboring cell; and receiving, by the first base station based on the interference channel information, an uplink signal sent by user equipment in a coverage area of the first base station. ### Claim 2 (depends on 1) The method according to claim 1, wherein the obtaining, by the first base station, system information of a neighboring cell comprises: obtaining, by the first base station, physical cell identifier (PCI) information of the neighboring cell using a sniffer; and obtaining, by the first base station, the system information of the neighboring cell using the PCI information. ### Claim 3 (depends on 2) The method according to claim 2, wherein the determining, by the first base station, interference channel information of a second base station to the first base station based on the system information comprises: determining, by the first base station, a multiple-input multiple-output system (MIMO) interference channel matrix of the second base station to the first base station based on the system information. ### Claim 4 (depends on 3) The method according to claim 3, wherein the determining, by the first base station, the MIMO interference channel matrix of the second base station to the first base station based on the system information comprises: determining, by the first base station, the MIMO interference channel matrix of the second base station to the first base station using a synchronization sequence and a cell-specific reference signal (CRS) pilot sequence of the neighboring cell. ### Claim 5 (depends on 3) The method according to claim 3, wherein the receiving, by the first base station based on the interference channel information, the uplink signal sent by user equipment in the coverage area of the first base station comprises: determining, by the first base station, a corresponding interference autocorrelation matrix based on the MIMO interference channel matrix; and using, by the first base station, the interference autocorrelation matrix to receive, using an interference rejection combining (IRC) receiver, the uplink signal sent by the user equipment in the coverage area of the first base station. ### Claim 6 (depends on 1) The method according to claim 1, wherein the method further comprises: sending, by the first base station, the interference channel information to the second base station. ### Claim 7 An interference cancellation method, comprising: receiving, by a second base station, interference channel information of the second base station to a first base station that is sent by the first base station, wherein the interference channel information is determined by the first base station based on system information, and the system information is system information of a cell in which the second base station is located; and sending, by the second base station, a downlink signal to user equipment in a coverage area of the second base station based on the interference channel information. ### Claim 8 (depends on 7) The method according to claim 7, wherein the sending, by the second base station, the downlink signal to user equipment in the coverage area of the second base station based on the interference channel information comprises: sending, by the second base station based on the interference channel information, the downlink signal to the user equipment in the coverage area of the second base station in a null forming manner, wherein a null forming direction of a transmit beam used by the second base station to send the downlink signal is aligned with the first base station. ### Claim 9 (depends on 8) The method according to claim 8, wherein the interference channel information is a multiple-input multiple-output system (MIMO) interference channel matrix of the second base station to the first base station; and the sending, by the second base station based on the interference channel information, the downlink signal to the user equipment in the coverage area of the second base station in a null forming manner comprises: performing, by the second base station, singular value decomposition on the MIMO interference channel matrix to obtain the following factorization: HCeNB1=UHΛHVH wherein HCeNB1 is the MIMO interference channel matrix of the second base station to the first base station, UH and VH are singular vectors corresponding to HCeNB1, HCeNB1 is an m*n matrix, UH is a corresponding m*m matrix, and VH is a corresponding n*n matrix; determining, by the second base station, a quantity y of non-zero singular values of ΛH; using, by the second base station, a vector behind a column y+1 of VH as a transmit null forming weight for the downlink signal; and sending, by the second base station, the downlink signal to the user equipment in the coverage area of the second base station based on the transmit null forming weight. ### Claim 10 A first base station, comprising: a processor; and a non-transitory computer-readable storage medium coupled to the processor and storing programming instructions for execution by the processor, the programming instructions instruct the processor to: obtain system information of a neighboring cell; determine interference channel information of a second base station to the first base station based on the system information, wherein the second base station is a base station in a coverage area of the neighboring cell; and receive, based on the interference channel information, an uplink signal sent by user equipment in a coverage area of the first base station. ### Claim 11 (depends on 10) The base station according to claim 10, wherein the programming instructions instruct the processor to obtain system information of the neighboring cell comprises the programming instructions to instruct the processor to: obtain physical cell identifier (PCI) information of the neighboring cell using a sniffer; and obtain the system information of the neighboring cell using the PCI information. ### Claim 12 (depends on 11) The base station according to claim 11, wherein the programming instructions instruct the processor to determine interference channel information of the second base station to the first base station based on the system information comprises the programming instructions to instruct the processor to: determine a multiple-input multiple-output system (MIMO) interference channel matrix of the second base station to the first base station based on the system information. ### Claim 13 (depends on 12) The base station according to claim 12, wherein the programming instructions instruct the processor to determine the MIMO interference channel matrix of the second base station to the first base station based on the system information comprises the programming instructions to instruct the processor to: determine the MIMO interference channel matrix of the second base station to the first base station using a synchronization sequence and a cell-specific reference signal (CRS) pilot sequence of the neighboring cell. ### Claim 14 (depends on 12) The base station according to claim 12, wherein the programming instructions instruct the processor to receive, based on the interference channel information, the uplink signal sent by user equipment in the coverage area of the first base station comprises the programming instructions to instruct the processor to: determine a corresponding interference autocorrelation matrix based on the MIMO interference channel matrix; and use the interference autocorrelation matrix to receive, using an interference rejection combining (IRC) receiver, the uplink signal sent by the user equipment in the coverage area of the first base station. ### Claim 15 (depends on 10) The base station according to claim 10, wherein the programming instructions further instruct the processor to: send the interference channel information to the second base station, wherein the second base station sends a downlink signal based on the interference channel information when sending the downlink signal to user equipment in a coverage area of the second base station. ### Claim 16 A second base station, comprising: a processor; and a non-transitory computer-readable storage medium coupled to the processor and storing programming instructions for execution by the processor, the programming instructions instruct the processor to: receive interference channel information of the second base station to a first base station that is sent by the first station, wherein the interference channel information is determined by the first base station based on system information, and the system information is system information of a cell in which the second base station is located; and send a downlink signal to user equipment in a coverage area of the second base station based on the interference channel information. ### Claim 17 (depends on 16) The base station according to claim 16, wherein the programming instructions instruct the processor to send the downlink signal to user equipment in the coverage area of the second base station based on the interference channel information comprises the programming instructions to instruct the processor to: send, based on the interference channel information, the downlink signal to the user equipment in the coverage area of the second base station in a null forming manner, wherein a null forming direction of a transmit beam used by the second base station to send the downlink signal is aligned with the first base station. ### Claim 18 (depends on 17) The base station according to claim 17, wherein the interference channel information is a multiple-input multiple-output system (MIMO) interference channel matrix of the second base station to the first base station; and the programming instructions further instruct the processor to: perform singular value decomposition on the MIMO interference channel matrix to obtain the following factorization: HCeNB1=UHΛHVH, wherein HCeNB1 is the MIMO interference channel matrix of the second base station to the first base station, UH and VH are singular vectors corresponding to HCeNB1, HCeNB1 is an m*n matrix, UH is a corresponding m*m matrix, and VH is a corresponding n*n matrix; determine a quantity y of non-zero singular values of ΛH; and use a vector behind a column y+1 of VH as a transmit null forming weight for the downlink signal; and the programming instructions instruct the processor to send, based on the interference channel information, the downlink signal to the user equipment in the coverage area of the second base station in the null forming manner comprises the programming instructions to instruct the processor to: send the downlink signal to the user equipment in the coverage area of the second base station based on the transmit null forming weight.