# US 10,455,622 B2 · Performing a random access procedure in a carrier aggregation with at least one SCell operating in an unlicensed spectrum > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,455,622 B2 - Document ID: US10455622B2 - Status: Granted - Kind: B2 - Application number: 15/555,475 - Filed: 2016-04-06 - Published: 2018-02-15 - Granted: 2019-10-22 - Earliest claimed: 2015-04-10 - Assignees: LG Electronics Inc. - Applicants: LG Electronics Inc. - Inventors: Sunyoung Lee; Seungjune Yi - Web page: https://patentgrep.com/patent/US10455622B2 ## CPC - H04W 74/0833: Random access procedures, e.g. with 4-step access - H04W 72/0446: Resources in time domain, e.g. slots or frames - H04W 72/23: in the downlink direction of a wireless link, i.e. towards a terminal - H04L 5/001: {the frequencies being arranged in component carriers} - H04L 27/0006: {Assessment of spectral gaps suitable for allocating digitally modulated signals, e.g. for carrier allocation in cognitive radio (for spectrum sharing between different networks H04W16/14)} - H04W 16/14: Spectrum sharing arrangements {between different networks} - H04W 74/0838: using contention-free random access [CFRA] - H04W 88/02: Terminal devices - H04W 88/16: Gateway arrangements - H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72) - H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M) ## Abstract A method and a device for performing a random access procedure in a carrier aggregation with at least one SCell operating in an unlicensed spectrum are disclosed. The method includes: configuring a timer; starting the timer when the UE initiates a Random Access Preamble (RAP) transmission procedure on a first cell; and stopping the RAP transmission procedure on the first cell if a Random Access Response (RAR) for the RAP transmission procedure on the first cell is not received until the timer expires. ## Claims ### Claim 1 A method for a User Equipment (UE) operating in a wireless communication system, the method comprising: initiating a Random Access Preamble (RAP) transmission procedure on an unlicensed Secondary Cell (SCell), wherein a timer is started when the UE initiates the RAP transmission procedure on the unlicensed SCell; stopping the RAP transmission procedure on the unlicensed SCell when a certain condition is met, wherein the certain condition is met when the RAP has not been transmitted within a predefined number of subframes from a subframe where the timer expires, even when a number of the RAP transmissions is less than a threshold value; and transmitting, to a Base Station (BS), information on the UE stopping the RAP transmission procedure on the unlicensed SCell through a cell configured for the UE when the RAP transmission procedure on the unlicensed SCell is stopped. ### Claim 2 (depends on 1) The method according to claim 1, wherein the cell configured for the UE is a or Primary Cell (PCell), a Primary Secondary Cell (PSCell), any cell among serving cells belonging to the BS on a licensed spectrum, or any cell among cells on an unlicensed spectrum and not occupied by other transmitters. ### Claim 3 (depends on 1) The method according to claim 1, wherein the information is transmitted via Physical layer (PHY), Medium Access Control (MAC), Radio Link Control (RLC), Packet Data Convergence Protocol (PDCP), or Radio Resource Control (RRC) signal. ### Claim 4 (depends on 1) The method according to claim 1, wherein the information includes an identification of the unlicensed SCell on which the RAP transmission procedure is stopped, or an identification of the RAP of which the transmission on the unlicensed SCell is stopped. ### Claim 5 (depends on 1) The method according to claim 1, wherein the UE initiates the RAP transmission procedure on the unlicensed SCell when a Physical Downlink Control Channel (PDCCH) order is received from the BS. ### Claim 6 A User Equipment (UE) operating in a wireless communication system, the UE comprising: a Radio Frequency (RF) module; and a processor operably coupled with the RF module and configured to: initiate a Random Access Preamble (RAP) transmission procedure on an unlicensed Secondary Cell (SCell), wherein a timer is started when the processor initiates the RAP transmission procedure on the unlicensed SCell; stop the RAP transmission procedure on the unlicensed SCell when a certain condition is met, wherein the certain condition is met when the RAP has not been transmitted within a predefined number of subframes from a subframe where the timer expires, even when a number of the RAP transmissions is less than a threshold value; and transmit, to a base station (BS), information on the processor stopping the RAP transmission procedure on the unlicensed SCell through a cell configured for the UE when the RAP transmission procedure on the unlicensed SCell is stopped. ### Claim 7 (depends on 6) The UE according to claim 6, wherein the second cell configured for the UE is a Primary Cell (PCell), a Primary Secondary Cell (PSCell), any cell among serving cells belonging to the BS on a licensed spectrum, or any cell among cells on an unlicensed spectrum and not occupied by other transmitters. ### Claim 8 (depends on 6) The UE according to claim 6, wherein the information includes an identification of the unlicensed SCell on which the RAP transmission procedure is stopped, or an identification of the RAP of which the transmission on the unlicensed SCell is stopped. ### Claim 9 (depends on 6) The UE according to claim 6, wherein the UE initiates the RAP transmission procedure on the unlicensed SCell when a Physical Downlink Control Channel (PDCCH) order is received from the BS. ### Claim 10 (depends on 6) The UE according to claim 6, wherein the information is transmitted via Physical layer (PHY), Medium Access Control (MAC), Radio Link Control (RLC), Packet Data Convergence Protocol (PDCP), or Radio Resource Control (RRC) signal.