# US 2019/0159038 A1 · Link restoration method and apparatus, and device > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2019/0159038 A1 - Document ID: US20190159038A1 - Status: Published application - Kind: A1 - Application number: 16/252,473 - Filed: 2019-01-18 - Published: 2019-05-23 - Earliest claimed: 2016-07-26 - Assignees: Huawei Technologies Co., Ltd. - Applicants: Huawei Technologies Co., Ltd. - Inventors: Kaili Xu; Kaijun Cheng; Ji Wu; Yingpei Lin - Web page: https://patentgrep.com/patent/US20190159038A1 ## CPC - H04W 16/28: using beam steering - H04B 7/0617: {for beam forming} - H04W 24/04: Arrangements for maintaining operational condition - H04W 72/0446: Resources in time domain, e.g. slots or frames - H04W 74/0808: using carrier sensing, e.g. carrier sense multiple access [CSMA] - H04W 76/19: Connection re-establishment - H04W 24/08: Testing, {supervising or monitoring} using real traffic - H04W 72/046: {the resource being in the space domain, e.g. beams} - H04W 84/12: WLAN [Wireless Local Area Networks] - H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72) - H04B: TRANSMISSION ## Abstract Embodiments of this application provide a link restoration method and apparatus, and a device. The method includes: if quality of a link between a first communications device and a second communications device does not meet a preset condition, detecting, by the first communications device within timing duration of a first timer, whether the link is restored, and obtaining a detection result, where the timing duration of the first timer is blockage duration of a link blockage resulting from a user movement; and determining, by the first communications device based on the detection result, whether to perform a link restoration operation, where the link restoration operation includes at least one of a beam tracking operation, a beam refinement operation, or a redo-beamforming operation. ## Claims ### Claim 1 A link restoration method, comprising: when quality of a link between a first communications device and a second communications device does not meet a preset condition, detecting, by the first communications device within timing duration of a first timer, whether the link is restored, and obtaining a detection result, wherein the timing duration of the first timer is blockage duration of a link blockage resulting from a user movement; and determining, by the first communications device based on the detection result, whether to perform a link restoration operation, wherein the link restoration operation comprises at least one of a beam tracking operation, a beam refinement operation, or a redo-beamforming operation. ### Claim 2 (depends on 1) The method according to claim 1, wherein detecting, by the first communications device within timing duration of a first timer, whether the link is restored comprises: sending, by the first communications device, a null data packet (NDP) to the second communications device; and when the first communications device receives, before the first timer expires, response information sent by the second communications device, determining that the link is restored. ### Claim 3 (depends on 2) The method according to claim 2, wherein determining, by the first communications device based on the detection result, whether to perform a link restoration operation comprises: when the detection result is that restoration of the link is detected before the first timer expires, determining, by the first communications device, not to perform the beam tracking operation or the beam refinement operation, and resetting the first timer to an initial value, wherein the timing duration of the first timer is less than timing duration of a beam link maintenance timer. ### Claim 4 (depends on 2) The method according to claim 2, wherein determining, by the first communications device based on the detection result, whether to perform a link restoration operation comprises: when the detection result is that restoration of the link is detected after a beam link maintenance timer expires and before the first timer expires, determining, by the first communications device based on a detected link restoration moment, whether to perform the redo-beamforming operation. ### Claim 5 (depends on 4) The method according to claim 4, wherein determining, by the first communications device based on a detected link restoration moment, whether to perform the redo-beamforming operation comprises: when the detected link restoration moment is prior to an enabling moment of the redo-beamforming operation, determining, by the first communications device, not to perform the redo-beamforming operation. ### Claim 6 (depends on 4) The method according to claim 4, wherein: when restoration of the link is not detected before the redo-beamforming operation is enabled, determining, by the first communications device, to perform the redo-beamforming operation, and when detecting restoration of the link, transmitting data by using an initial beamforming pattern used before the redo-beamforming. ### Claim 7 (depends on 2) The method according to claim 2, wherein: when the detection result is that restoration of the link is not detected when the first timer expires, and when the redo-beamforming operation is not enabled, link detection is stopped, and the redo-beamforming operation waits to be performed, wherein the timing duration of the first timer is greater than timing duration of a beam link maintenance timer; or when the detection result is that restoration of the link is not detected when the first timer expires, and when the redo-beamforming operation is enabled after a beam link maintenance timer expires and before the first timer expires, data is transmitted by using a beam parameter obtained after the redo-beamforming. ### Claim 8 (depends on 1) The method according to claim 1, wherein before detecting, by the first communications device within timing duration of a first timer, whether the link is restored, the method further comprises: determining, by the first communications device, the timing duration of the first timer based on a current communication scenario, wherein the communication scenario comprises any one of a blockage scenario of a home living room, a blockage scenario of dense wearables use in airplane, and a blockage scenario of an office conference room; and sending, by the first communications device, the timing duration of the first timer to the second communications device. ### Claim 9 (depends on 8) The method according to claim 8, wherein sending, by the first communications device, the timing duration of the first timer to the second communications device comprises: adding, by the first communications device, the timing duration of the first timer to a communication frame, and sending the communication frame to the second communications device, wherein the communication frame comprises any one of a probe frame, an announce frame, an information request frame, and a response frame; wherein the communication frame comprises: an Element ID field representing an identifier of an Element including the timing duration of the first timer, a link blockage maintenance field, and a Length field used to represent a length of the link blockage maintenance field; and the link blockage maintenance field is used to represent the timing duration of the first timer in the current communication scenario. ### Claim 10 (depends on 1) The method according to claim 1, further comprising: enabling the first timer when data is transmitted between the first communications device and the second communications device, and resetting the first timer when the first communications device transmits first information, wherein the first information comprises at least one of an immediate response, a request for service period, a polling frame, an authorization frame, a request frame, an acknowledgement frame, a block acknowledgement frame, a directional multi-gigabit deny-to-send frame, and a directional multi-gigabit clear-to-send frame. ### Claim 11 A communications device, comprising: a processor, configured to: when quality of a link between the communications device and a second communications device does not meet a preset condition, detect, within timing duration of a first timer, whether the link is restored, obtain a detection result, and determine, based on the detection result, whether to perform a link restoration operation, wherein the timing duration of the first timer is blockage duration of a link blockage resulting from a user movement, and the link restoration operation comprises at least one of a beam tracking operation, a beam refinement operation, or a redo-beamforming operation. ### Claim 12 (depends on 11) The communications device according to claim 11, further comprising: a transmitter configured to send a null data packet (NDP) to the second communications device; a receiver; and wherein the processor is configured to: when the receiver receives, before the first timer expires, response information sent by the second communications device, determine that the link is restored. ### Claim 13 (depends on 12) The communications device according to claim 12, wherein the processor is configured to: when the detection result is that restoration of the link is detected before the first timer expires, determine not to perform the beam tracking operation or the beam refinement operation, and reset the first timer to an initial value, wherein the timing duration of the first timer is less than timing duration of a beam link maintenance timer. ### Claim 14 (depends on 12) The communications device according to claim 12, wherein the processor is configured to: when the detection result is that restoration of the link is detected after a beam link maintenance timer expires and before the first timer expires, determine, based on a detected link restoration moment, whether to perform the redo-beamforming operation. ### Claim 15 (depends on 14) The communications device according to claim 14, wherein the processor is configured to: when the detected link restoration moment is prior to an enabling moment of the redo-beamforming operation, determine not to perform the redo-beamforming operation. ### Claim 16 (depends on 14) The communications device according to claim 14, wherein the processor is configured to: when restoration of the link is not detected before the redo-beamforming operation is enabled, determine to perform the redo-beamforming operation, and when detecting restoration of the link, transmit data by using an initial beamforming pattern used before the redo-beamforming. ### Claim 17 (depends on 12) The communications device according to claim 12, wherein the processor is configured to: when the detection result is that restoration of the link is not detected when the first timer expires, and if the redo-beamforming operation is not enabled, stop link detection, and wait to perform the redo-beamforming operation, wherein the timing duration of the first timer is greater than timing duration of a beam link maintenance timer; or when the detection result is that restoration of the link is not detected when the first timer expires, and if the redo-beamforming operation is enabled after a beam link maintenance timer expires and before the first timer expires, transmit data by using a beam parameter obtained after the redo-beamforming. ### Claim 18 (depends on 11) The communications device according to claim 11, wherein: the processor is further configured to: determine the timing duration of the first timer based on a current communication scenario, wherein the communication scenario comprises any one of a blockage scenario of a home living room, a blockage scenario of dense wearables use in airplane, and a blockage scenario of an office conference room; and the transmitter is configured to: send the timing duration of the first timer to the second communications device. ### Claim 19 (depends on 18) The communications device according to claim 18, wherein: the transmitter is configured to add the timing duration of the first timer to a communication frame, and send the communication frame to the second communications device, wherein the communication frame comprises any one of a probe frame, an announce frame, an information request frame, and a response frame; the communication frame comprises: an Element ID field representing an identifier of an Element including the timing duration of the first timer, a link blockage maintenance field, and a Length field used to represent a length of the link blockage maintenance field; and the link blockage maintenance field is used to represent the timing duration of the first timer in the current communication scenario. ### Claim 20 (depends on 11) The communications device according to claim 11, wherein the processor is further configured to: enable the first timer when data is transmitted between the communications device and the second communications device, and reset the first timer when the communications device transmits first information, wherein the first information comprises at least one of an immediate response, a request for service period, a polling frame, an authorization frame, a request frame, an acknowledgement frame, a block acknowledgement frame, a directional multi-gigabit deny-to-send frame, and a directional multi-gigabit clear-to-send frame.