# US 2021/0344385 A1 · User device beamforming training in wireless networks > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2021/0344385 A1 - Document ID: US20210344385A1 - Status: Published application - Kind: A1 - Application number: 17/305,699 - Filed: 2021-07-13 - Published: 2021-11-04 - Earliest claimed: 2018-05-22 - Assignees: Nokia Solutions and Networks Oy - Applicants: Nokia Solutions and Networks Oy - Inventors: Sami-Jukka Hakola; Esa Tapani Tiirola - Web page: https://patentgrep.com/patent/US20210344385A1 ## CPC - H04B 7/0417: Feedback systems - H04B 7/0617: {for beam forming} - H04W 36/0016: {Hand-off preparation specially adapted for end-to-end data sessions} - H04W 36/04: Reselecting a cell layer in multi-layered cells - H04W 72/046: {the resource being in the space domain, e.g. beams} - H04W 72/542: using measured or perceived quality - H04W 74/0833: Random access procedures, e.g. with 4-step access - H04B: TRANSMISSION - H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72) ## Abstract A technique is provided for beamforming training, including: transmitting, by a network node, common control signaling via a plurality of beams periodically according to a predetermined beam sweeping pattern, and transmitting, via a set of one or more beams in each of one or more sequential time-domain resources, an aperiodic downlink sounding burst to at least one user device to allow the at least one user device to perform beamforming training. ## Claims ### Claim 1 An apparatus comprising at least one processor and at least one memory including computer instructions, when executed by the at least one processor, cause the apparatus to: transmit common control signaling via a plurality of beams periodically according to a predetermined beam sweeping pattern; and transmit, via a transmission beam in each of one or more sequential time-domain resources, an aperiodic downlink sounding burst to at least one user device to enable the at least one user device to perform beamforming training. ### Claim 2 (depends on 1) The apparatus of claim 1 wherein a number of the one or more sequential time-domain resources for the transmission of the downlink sounding burst is based on a number of transmit beams and/or receive beams of the at least one user device. ### Claim 3 (depends on 1) The apparatus of claim 1, wherein the transmitting, via the transmission beam and the set of one or more receiving beams in each of one or more sequential time-domain resources, the aperiodic downlink sounding burst is triggered based on one of a plurality of triggering methods; and wherein a number of the one or more sequential time-domain resources for the transmission of the downlink sounding burst is based on the one of the plurality of triggering methods. ### Claim 4 (depends on 1) The apparatus of claim 1, wherein the transmission beam and the set of one or more receiving beams used to transmit the aperiodic downlink sounding burst are derived based on at least one of a user device triggering that triggers the transmitting the downlink sounding burst and an uplink channel measurement by the network node. ### Claim 5 (depends on 1) The apparatus of claim 1. wherein the transmitting, via a set of one or more beams in each of one or more sequential time-domain resources, the aperiodic downlink sounding burst is triggered based on an occurrence of one of a plurality of triggering methods that include a first category of triggering methods and a second category of triggering methods; and wherein a number of the one or more sequential time-domain resources for the transmission of the downlink sounding burst is fixed for the first category of triggering methods, and is adjustable by the network node for the second category of triggering methods. ### Claim 6 (depends on 5) The apparatus of claim 5, wherein the first category of triggering methods comprises triggering the transmitting of the aperiodic downlink sounding burst in response to a random access preamble of a random access procedure; and wherein the second category of triggering methods comprises triggering the transmitting the aperiodic downlink sounding burst in response to receiving at least one of the following: a handover message, a channel state information feedback, and a subsequent message of the random access procedure. ### Claim 7 (depends on 1) The apparatus of claim 1, wherein the computer instructions, when executed by the at least one processor, further cause the apparatus to: transmit a list of a plurality of random access resources that includes a non-triggering resource that is not associated with triggering the transmission of the aperiodic downlink sounding burst, and a triggering resource that is associated with triggering the transmission of the aperiodic downlink sounding burst; and receive, by the network node via the triggering resource, a random access preamble, wherein the transmitting the aperiodic downlink sounding burst is triggered by the network node in response to receiving the random access preamble via the triggering resource. ### Claim 8 (depends on 1) The apparatus of claim 1, wherein the computer instructions, when executed by the at least one processor, further cause the apparatus to: transmit scheduling information indicating the one or more sequential time-domain resources for the transmission of the aperiodic downlink sounding burst to the user device upon detecting an occurrence of the second category of triggering methods; and cause a transmission of the aperiodic downlink sounding burst to the user device according to the determined scheduling information. ### Claim 9 (depends on 1) The apparatus of claim 1, wherein the network node comprises a network node of a source cell of a handover, and wherein the computer instructions, when executed by the at least one processor, further cause the apparatus to: receive, by the network node of the source cell, a handover message indicating a handover of the user device to the network node; receive, by the network node of the source cell from a network node of a target cell of the handover, scheduling information indicating one or more resources of the target cell of the handover for transmission of the downlink sounding burst; and send, by the network node of the source cell to the user device, the scheduling information for the transmission of the aperiodic downlink sounding burst by the network node of the target cell. ### Claim 10 (depends on 1) The apparatus of claim 1, wherein the network node comprises a network node of a target cell of a handover, and wherein the computer instructions, when executed by the at least one processor, further cause the apparatus to: determine scheduling information indicating one or more sequential time-domain resources for the transmission of the aperiodic downlink sounding burst to the user device; transmit the scheduling information to a network node of a source cell of the handover; and cause a transmission of the aperiodic downlink sounding burst to the user device according to the determined scheduling information after the handover has been performed for the user device. ### Claim 11 A method for beamforming training, comprising: receiving, by a user device from a network node, common control signaling via a plurality of beams periodically according to a predetermined beam sweeping pattern; receiving, via a transmission beam in each of a plurality of sequential time-domain resources, an aperiodic downlink sounding burst; and performing beamforming training of a set of one or more receiving beams based on the aperiodic downlink sounding burst to select a downlink receive beam for receiving signals from the network node. ### Claim 12 (depends on 11) The method of claim 11, further comprising: receiving a list of a plurality of random access resources that includes a non-triggering resource that is not associated with triggering the transmission of the aperiodic downlink sounding burst, and a triggering resource that is associated with triggering the transmission of the aperiodic downlink sounding burst; and transmitting, by the user device to the network node via the triggering resource, a random access preamble, wherein the receiving the aperiodic downlink sounding burst comprises receiving, via a set of one or more beams in each of a plurality of sequential time-domain resources, the aperiodic downlink sounding burst based on the transmission of the random access preamble via the triggering resource. ### Claim 13 (depends on 11) The method of claim 11, further comprising: determining, by the user device, a group of N best beams or antenna ports of the network node based on the reception of the common control signaling; and transmitting an indication of the group of N best beams or antenna ports to the network node. ### Claim 14 (depends on 11) The method of claim 11, further comprising: transmitting, by the user device, an indication to the network node in order to instruct the network node to trigger a transmission of the aperiodic downlink sounding burst to the user device, wherein the indication is one of the following: a transmission of a random access preamble, a transmission of a further message in a random access procedure, a transmission of a channel state information feedback, and a transmission of a handover request. ### Claim 15 (depends on 11) The method of claim 11, further comprising: receiving scheduling information from the network node after transmitting the indication, wherein the scheduling information indicates downlink resources for the reception, by the user device, of the aperiodic downlink sounding burst. ### Claim 16 An apparatus comprising at least one processor and at least one memory including computer instructions, when executed by the at least one processor, cause the apparatus to: receive, by a user device from a network node, common control signaling via a plurality of beams periodically according to a predetermined beam sweeping pattern; receive, via a transmission beam in each of a plurality of sequential time-domain resources, an aperiodic downlink sounding burst; and perform beamforming training of a set of one or more receiving beams based on the aperiodic downlink sounding burst to select a downlink receive beam for receiving signals from the network node. ### Claim 17 (depends on 16) The apparatus of claim 16, wherein the computer instructions, when executed by the at least one processor, further cause the apparatus to: receive a list of a plurality of random access resources that includes a non-triggering resource that is not associated with triggering the transmission of the aperiodic downlink sounding burst, and a triggering resource that is associated with triggering the transmission of the aperiodic downlink sounding burst; and transmit, by the user device to the network node via the triggering resource, a random access preamble, wherein the receiving the aperiodic downlink sounding burst comprises receiving, via a set of one or more beams in each of a plurality of sequential time-domain resources, the aperiodic downlink sounding burst based on the transmission of the random access preamble via the triggering resource. ### Claim 18 (depends on 16) The apparatus of claim 16, wherein the computer instructions, when executed by the at least one processor, further cause the apparatus to: determine, by the user device, a group of N best beams or antenna ports of the network node based on the reception of the common control signaling; and transmit an indication of the group of N best beams or antenna ports to the network node. ### Claim 19 (depends on 16) The apparatus of claim 16, wherein the computer instructions, when executed by the at least one processor, further cause the apparatus to: transmit, by the user device, an indication to the network node in order to instruct the network node to trigger a transmission of the aperiodic downlink sounding burst to the user device, wherein the indication is one of the following: a transmission of a random access preamble, a transmission of a further message in a random access procedure, a transmission of a channel state information feedback, and a transmission of a handover request. ### Claim 20 (depends on 16) The apparatus of claim 16, wherein the computer instructions, when executed by the at least one processor, further cause the apparatus to: receive scheduling information from the network node after transmitting the indication, wherein the scheduling information indicates downlink resources for the reception, by the user device, of the aperiodic downlink sounding burst.