# US 2018/0027593 A1 · Method and apparatus for random access in wireless communication > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2018/0027593 A1 - Document ID: US20180027593A1 - Status: Published application - Kind: A1 - Application number: 15/654,679 - Filed: 2017-07-19 - Published: 2018-01-25 - Earliest claimed: 2016-07-20 - Assignees: Electronics and Telecommunications Research Instit ute - Applicants: Electronics and Telecommunications Research Institute - Inventors: Changhee LEE - Web page: https://patentgrep.com/patent/US20180027593A1 ## CPC - H04L 5/003: {Arrangements for allocating sub-channels of the transmission path} - H04W 74/002: {Transmission of channel access control information} - H04W 74/0833: Random access procedures, e.g. with 4-step access - H04W 76/00: Connection management - H04W 68/00: User notification, e.g. alerting and paging, for incoming communication, change of service or the like - H04W 72/046: {the resource being in the space domain, e.g. beams} - H04W 76/30: Connection release - H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M) - 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, a terminal, and a base station for performing random access by receiving additional random access information from the base station after connecting to the base station, selecting a random access preamble based on the additional random access information, and performing the random access by using the selected random access preamble is provided. ## Claims ### Claim 1 A method for performing random access by a terminal, comprising: receiving additional random access information from a base station after connecting to the base station; selecting a random access preamble based on the additional random access information; and performing the random access by using the selected random access preamble. ### Claim 2 (depends on 1) The method of claim 1, wherein the additional random access information includes an index indicating a specific random access resource or an index indicating a specific random access resource group. ### Claim 3 (depends on 1) The method of claim 1, wherein the receiving additional random access information comprises receiving a paging message from the base station, the method further comprising, if the paging message includes the additional random access information, selecting the random access preamble based on the additional random access information, and if the paging message does not include the additional random access information, performing the random access according to the existing random access procedure. ### Claim 4 (depends on 1) The method of claim 1, wherein the receiving additional random access information comprises receiving a radio resource control (RRC) connection reconfiguration message from the base station, wherein the RRC connection reconfiguration message includes the additional random access information. ### Claim 5 (depends on 1) The method of claim 1, wherein the receiving additional random access information comprises receiving a radio resource control (RRC) connection release message from the base station, wherein the RRC connection release message includes the additional random access information. ### Claim 6 (depends on 1) The method of claim 1, further comprising executing an additional random access timer for indicating a valid time duration of the additional random access information, and the selecting a random access preamble based on the additional random access information comprises selecting the random access preamble based on the additional random access information when the connecting to the base station is completed before the additional random access timer expires. ### Claim 7 (depends on 6) The method of claim 6, further comprising deleting the additional random access information after the additional random access timer expires. ### Claim 8 A terminal performing random access, comprising a processor, a memory, and a radio frequency (RF) unit, wherein the processor executes a program stored in the memory to: receive additional random access information from a base station after connecting to the base station; select a random access preamble based on the additional random access information; and perform the random access by using the selected random access preamble. ### Claim 9 (depends on 8) The terminal of claim 8, wherein the additional random access information includes an index indicating a specific random access resource or an index indicating a specific random access resource group. ### Claim 10 (depends on 8) The terminal of claim 8, wherein, when receiving additional random access information, the processor receives a paging message from the base station, and the processor executes the program to further perform, if the paging message includes the additional random access information, selecting the random access preamble based on the additional random access information, while if the paging message does not include the additional random access information, to perform the random access according to the existing random access procedure. ### Claim 11 (depends on 8) The terminal of claim 8, wherein, when receiving additional random access information, the processor receives a radio resource control (RRC) connection reconfiguration message from the base station, wherein the RRC connection reconfiguration message includes the additional random access information. ### Claim 12 (depends on 8) The terminal of claim 8, wherein, when receiving additional random access information, the processor receives a radio resource control (RRC) connection release message from the base station, wherein the RRC connection release message includes the additional random access information. ### Claim 13 (depends on 8) The terminal of claim 8, wherein the processor executes the program to further executes an additional random access timer for indicating a valid time duration of the additional random access information, and when selecting a random access preamble based on the additional random access information, the processor selects the random access preamble based on the additional random access information when the connecting to the base station is completed before the additional random access timer expires. ### Claim 14 (depends on 13) The terminal of claim 13, wherein the processor executes the program to delete the additional random access information after the additional random access timer expires. ### Claim 15 A base station, comprising: a processor, a memory, and a radio frequency (RF) unit, wherein the processor executes a program stored in the memory to: transmit additional random access information to a terminal after the terminal is connected to the base station; receive a random access preamble selected based on the additional random access information; and transmit uplink resource allocation information to the terminal. ### Claim 16 (depends on 15) The base station of claim 15, wherein the additional random access information includes an index indicating a specific random access resource or an index indicating a specific random access resource group. ### Claim 17 (depends on 15) The base station of claim 15, wherein, when transmitting additional random access information, the processor transmits a radio resource control (RRC) connection reconfiguration message including the additional random access information to the terminal. ### Claim 18 (depends on 15) The base station of claim 15, wherein when transmitting additional random access information, the processor transmits a radio resource control (RRC) connection release message including the additional random access information to the terminal. ### Claim 19 (depends on 15) The base station of claim 15, wherein the processor further executes the program to delete the additional random access information after an additional random access timer for indicating a valid time duration of the additional random access information expires.