# US 11,122,579 B2 · Communication system and method for mitigating interference in hierarchical cell structure > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,122,579 B2 - Document ID: US11122579B2 - Status: Granted - Kind: B2 - Application number: 16/939,827 - Filed: 2020-07-27 - Published: 2020-11-19 - Granted: 2021-09-14 - Earliest claimed: 2009-04-01 - Assignees: Samsung Electronics Co., Ltd. - Applicants: Samsung Electronics Co., Ltd. - Inventors: Sang Min Lee; Tak Ki Yu; Yung Soo Kim - Web page: https://patentgrep.com/patent/US11122579B2 ## CPC - H04W 72/541: using the level of interference - H04W 16/32: Hierarchical cell structures - H04W 24/08: Testing, {supervising or monitoring} using real traffic - H04W 72/0446: Resources in time domain, e.g. slots or frames - H04W 72/29: between an access point and the access point controlling device - H04W 72/23: in the downlink direction of a wireless link, i.e. towards a terminal - H04W 88/08: Access point devices - H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72) ## Abstract A method for mitigating interference at a small base station in a hierarchical cell structure is provided. In the method, the small base station checks a sub-frame allocated to macro user equipment by using a downlink signal received from a macro base station when an interference candidate user equipment list is received. The interference candidate user equipment list contains information on the macro user equipment adjacent to a femto cell controlled by the small base station. Then the small base station allocates other sub-frame to femto user equipment located in the femto cell by avoiding the sub-frame allocated to the macro user equipment. ## Claims ### Claim 1 A method for mitigating interference at a first base station in a wireless communication system, the method comprising: receiving control information; identifying a first subframe so as to mitigate interference between the first base station and a second base station, based on the control information to process a signal; and allocating, based at least in part on the control information, the first subframe as a first resource for communication between the first base station and a user equipment in communication with the first base station in the wireless communication system, wherein the first subframe is not allocated as a resource associated with data for communication between the second base station and a user equipment in communication with the second base station in the wireless communication system, wherein a ratio of the first subframe and a second subframe is determined based on information exchanged between the first base station and the second base station, and wherein the second subframe is allocated as a second resource for communication between the second base station and a user equipment in communication with the second base station in the wireless communication system. ### Claim 2 (depends on 1) The method of claim 1, wherein the control information is received via a wired backhaul. ### Claim 3 (depends on 1) The method of claim 1, wherein a transmission power of the first base station is increased when the user equipment in communication with the first base station in the wireless communication system is interfered with by the user equipment in communication with the second base station in the wireless communication system. ### Claim 4 A first base station in a wireless communication system, the first base station comprising: a transceiver for transmitting and receiving a signal; and a controller for receiving control information, identifying a first subframe so as to mitigate interference between the first base station and a second base station, based on the control information to process a signal, and allocating, based at least in part on the control information, the first subframe as a first resource for communication between the first base station and a user equipment in communication with the first base station in the wireless communication system, wherein the first subframe is not allocated as a resource associated with data for communication between the second base station and a user equipment in communication with the second base station in the wireless communication system, wherein a ratio of the first subframe and a second subframe is determined based on information exchanged between the first base station and the second base station, and wherein the second subframe is allocated as a second resource for communication between the second base station and a user equipment in communication with the second base station in the wireless communication system. ### Claim 5 (depends on 4) The first base station of claim 4, wherein the control information is received via a wired backhaul. ### Claim 6 (depends on 4) The first base station of claim 4, wherein a transmission power of the first base station is increased when the user equipment in communication with the first base station in the wireless communication system is interfered with by the user equipment in communication with the second base station in the wireless communication system. ### Claim 7 A method for mitigating interference at a first base station in a wireless communication system, the method comprising: receiving control information; identifying a subframe associated with a time so as to mitigate interference between the first base station and a second base station, based on the control information to process a signal; and allocating, based at least in part on the control information, the subframe as a first resource associated with a first measurement for a first resource allocation for communication between the first base station and a user equipment in communication with the first base station in the wireless communication system, wherein the first subframe is not allocated as a second resource associated with a second measurement for a second resource allocation for communication between the second base station and a user equipment in communication with the second base station in the wireless communication system. ### Claim 8 (depends on 7) The method of claim 7, wherein the control information is received via a wired backhaul. ### Claim 9 A first base station in a wireless communication system, the first base station comprising: a transceiver for transmitting and receiving a signal; and a controller for receiving control information, identifying a subframe associated with a time so as to mitigate interference between the first base station and a second base station, based on the control information to process a signal, and allocating, based at least in part on the control information, the subframe as a resource associated with a measurement for a resource allocation for communication between the first base station and a user equipment in communication with the first base station in the wireless communication system, wherein the first subframe is not allocated as a resource associated with a measurement for a resource allocation for communication between the second base station and a user equipment in communication with the second base station in the wireless communication system. ### Claim 10 (depends on 9) The first base station of claim 9, wherein the control information is received via a wired backhaul. ### Claim 11 A method for receiving a downlink signal by a user equipment in a wireless communication system, the method comprising: receiving control information from a first base station; based on the control information, identifying a first subframe allocated as a first resource associated with a first measurement for a first resource allocation for communication between the first base station and a user equipment in communication with the first base station in the wireless communication system; and receiving a downlink signal in the first subframe, wherein the first subframe is not allocated as a resource associated with a measurement for a resource allocation for communication between a second base station and a user equipment in communication with the second base station in the wireless communication system. ### Claim 12 (depends on 11) The method of claim 11, wherein a ratio of the first subframe and a second subframe is determined based on information exchanged between the first base station and the second base station, and wherein the second subframe is allocated as a second resource for communication between the first base station and a user equipment in communication with the first base station in the wireless communication system. ### Claim 13 (depends on 12) The method of claim 12, wherein a transmission power of the first base station is increased when the user equipment in communication with the first base station in the wireless communication system is interfered with by the user equipment in communication with the second base station in the wireless communication system. ### Claim 14 (depends on 13) The method of claim 13, further comprising: transmitting information indicating whether or not a reception of the downlink signal is successful. ### Claim 15 A user equipment for receiving a downlink signal in a wireless communication system, the user equipment comprising: a transceiver configured to transmit and receive a signal; and at least one processor configured to: control to receive control information from a first base station, based on the control information, identify a first subframe allocated as a first resource associated with a first measurement for a first resource allocation for communication between the first base station and a user equipment in communication with the first base station in the wireless communication system, and receive a downlink signal in the first subframe, wherein the first subframe is not allocated as a resource associated with a measurement for a resource allocation for communication between a second base station and a user equipment in communication with the second base station in the wireless communication system. ### Claim 16 (depends on 15) The user equipment of claim 15, wherein a ratio of the first subframe and a second subframe is determined based on information exchanged between the first base station and the second base station, and wherein the second subframe is allocated as a second resource for communication between the first base station and a user equipment in communication with the first base station in the wireless communication system. ### Claim 17 (depends on 15) The user equipment of claim 15, wherein a transmission power of the first base station is increased when the user equipment in communication with the first base station in the wireless communication system is interfered with by the user equipment in communication with the second base station in the wireless communication system. ### Claim 18 (depends on 15) The user equipment of claim 15, wherein the at least one processor is further configured to control to transmit information indicating whether or not a reception of the downlink signal is successful.