# US 12,193,066 B2 · Random access method and device > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,193,066 B2 - Document ID: US12193066B2 - Status: Granted - Kind: B2 - Application number: 17/713,290 - Filed: 2022-04-05 - Published: 2022-07-21 - Granted: 2025-01-07 - Earliest claimed: 2022-04-05 - Assignees: Beijing Xiaomi Mobile Software Co., Ltd. - Applicants: Beijing Xiaomi Mobile Software Co., Ltd. - Inventors: Xiaowei Jiang - Web page: https://patentgrep.com/patent/US12193066B2 ## CPC - H04W 76/27: Transitions between radio resource control [RRC] states - H04B 17/328: {Reference signal received power [RSRP]; Reference signal received quality [RSRQ]} - H04W 36/0072: {of resource information of target access point} - H04W 52/50: at the moment of starting communication in a multiple access environment - H04W 72/0453: Resources in frequency domain, e.g. a carrier in FDMA - H04W 72/21: in the uplink direction of a wireless link, i.e. towards the network - H04W 74/0833: Random access procedures, e.g. with 4-step access - H04W 36/0085: {Hand-off measurements} - H04W 36/08: Reselecting an access point - H04W 52/245: {taking into account received signal strength} - 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 A random access method includes: receiving, by a terminal, a radio resource control (RRC) message sent by a base station, the RRC message comprising a power threshold; detecting, by the terminal, a reference signal received power (RSRP) of a current downlink carrier; determining, by the terminal, a first uplink carrier among a plurality of uplink carriers corresponding to the base station according to the RSRP and the power threshold; and transmitting, by the terminal, a random access preamble to the base station using the first uplink carrier. The plurality of uplink carriers comprise a supplementary uplink (SUL) carrier and a non-SUL carrier. ## Claims ### Claim 1 A random access method, comprising: receiving, by a terminal, a carrier identifier of a first uplink carrier sent by a base station; determining, by the terminal, the first uplink carrier among a plurality of uplink carriers corresponding to the base station according to the carrier identifier of the first uplink carrier; and transmitting, by the terminal, a random access preamble to the base station using the first uplink carrier; wherein the plurality of uplink carriers comprise a supplementary uplink (SUL) carrier and a non-SUL carrier, and wherein receiving the carrier identifier of the first uplink carrier sent by the base station comprises: receiving, by the terminal, handover command information, the handover command information comprising the carrier identifier of the first uplink carrier. ### Claim 2 (depends on 1) The method according to claim 1, further comprising: receiving, by the terminal, a radio resource control (RRC) message sent by the base station, wherein the RRC message comprises the carrier identifier of the first uplink carrier. ### Claim 3 (depends on 1) The method according to claim 1, further comprising: receiving, by the terminal, reconfiguration information from the base station after the base station re-establishes a secondary cell group (SCG) or modifies the SCG, the reconfiguration information comprising the carrier identifier of the first uplink carrier. ### Claim 4 (depends on 1) The method according to claim 1, further comprising: receiving, by the terminal, a physical downlink control channel (PDCCH) command sent by the base station, the PDCCH command comprising the carrier identifier of the first uplink carrier. ### Claim 5 (depends on 1) A non-transitory computer-readable storage medium having stored thereon instructions that, when executed by a processor of a terminal device, cause the terminal device to perform the method of claim 1. ### Claim 6 (depends on 1) The method according to claim 1, further comprising: receiving, by the terminal, a radio resource control (RRC) message sent by the base station, the RRC message comprising a power threshold; detecting, by the terminal, a reference signal received power (RSRP) of a current downlink carrier; and determining, by the terminal, the first uplink carrier among the plurality of uplink carriers according to the RSRP and the power threshold. ### Claim 7 A random access method, comprising: transmitting, by a base station, a carrier identifier of a first uplink carrier; and receiving, by the base station, a random access preamble sent by a terminal using the first uplink carrier determined by the terminal among a plurality of uplink carriers corresponding to the base station according to the carrier identifier of the first uplink carrier; wherein the plurality of uplink carriers comprise a supplementary uplink (SUL) carrier and a non-SUL carrier, and the base station is a target base station, and transmitting the carrier identifier of the first uplink carrier comprises: receiving a handover request from an original base station; generating handover request response information comprising the carrier identifier of the first uplink carrier; and transmitting the handover request response information comprising the carrier identifier of the first uplink carrier to the original base station. ### Claim 8 (depends on 7) The method according to claim 7, further comprising: transmitting, by the base station, a radio resource control (RRC) message to the terminal, wherein the RRC message comprises the carrier identifier of the first uplink carrier. ### Claim 9 (depends on 7) The method according to claim 7, further comprising: re-establishing or modifying, by the base station, a secondary cell group (SCG); and transmitting, by the base station, reconfiguration information to the terminal, the reconfiguration information comprising the carrier identifier of the first uplink carrier. ### Claim 10 (depends on 7) The method according to claim 7, further comprising: transmitting, by the base station, a physical downlink control channel (PDCCH) command to the terminal, the PDCCH command comprising the carrier identifier of the first uplink carrier. ### Claim 11 (depends on 7) A base station, comprising: a processor; and a memory configured to store instructions executable by the processor; wherein the processor is configured to perform the method of claim 7. ### Claim 12 (depends on 7) A non-transitory computer-readable storage medium having stored thereon instructions that, when executed by a processor of a base station, cause the base station to perform the method of claim 7. ### Claim 13 (depends on 7) The method according to claim 7, further comprising: transmitting, by the base station, a radio resource control (RRC) message to the terminal, the RRC message comprising a power threshold; wherein the first uplink carrier is further determined by the terminal among the plurality of uplink carriers according to a reference signal received power (RSRP) of a current downlink carrier and the power threshold. ### Claim 14 A terminal device, comprising: a processor; and a memory configured to store instructions executable by the processor; wherein the processor is configured to: receive a carrier identifier of a first uplink carrier sent by a base station; determine the first uplink carrier among a plurality of uplink carriers corresponding to the base station according to the carrier identifier of the first uplink carrier, the plurality of uplink carriers comprising a supplementary uplink (SUL) carrier and a non-SUL carrier; transmit a random access preamble to the base station using the first uplink carrier; and receive handover command information, the handover command information comprising the carrier identifier of the first uplink carrier. ### Claim 15 (depends on 14) The terminal device according to claim 14, wherein the processor is further configured to: receive a radio resource control (RRC) message sent by the base station, wherein the RRC message comprises the carrier identifier of the first uplink carrier. ### Claim 16 (depends on 14) The terminal device according to claim 14, wherein the processor is further configured to: receive reconfiguration information from the base station after the base station re-establishes a secondary cell group (SCG) or modifies the SCG, the reconfiguration information comprising the carrier identifier of the first uplink carrier. ### Claim 17 (depends on 14) The terminal device according to claim 14, wherein the processor is further configured to: receive a physical downlink control channel (PDCCH) command sent by the base station, the PDCCH command comprising the carrier identifier of the first uplink carrier. ### Claim 18 (depends on 14) The terminal device according to claim 14, wherein the processor is further configured to: receive a radio resource control (RRC) message sent by the base station, the RRC message comprising a power threshold; detect a reference signal received power (RSRP) of a current downlink carrier; and determine the first uplink carrier among the plurality of uplink carriers according to the RSRP and the power threshold.