# US 12,225,591 B2 · Method and apparatus for initial access in communication system > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,225,591 B2 - Document ID: US12225591B2 - Status: Granted - Kind: B2 - Application number: 17/681,290 - Filed: 2022-02-25 - Published: 2022-09-01 - Granted: 2025-02-11 - Earliest claimed: 2021-02-26 - Assignees: Electronics and Telecommunications Research Institute - Applicants: Electronics and Telecommunications Research Institute - Inventors: Jung Hoon Lee; Cheul Soon Kim; Sung Hyun Moon - Web page: https://patentgrep.com/patent/US12225591B2 ## CPC - H04W 72/0446: Resources in time domain, e.g. slots or frames - H04L 5/003: {Arrangements for allocating sub-channels of the transmission path} - H04L 27/26025: {Numerology, i.e. varying one or more of symbol duration, subcarrier spacing, Fourier transform size, sampling rate or down-clocking (allocating sub-channels of the transmission path H04L5/003)} - H04L 27/26134: {Pilot insertion in the transmitter chain, e.g. pilot overlapping with data, insertion in time or frequency domain} - H04L 27/2647: {Arrangements specific to the receiver only (equalisation H04L27/01)} - H04W 74/0833: Random access procedures, e.g. with 4-step access - 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 An operation method of a terminal in a communication system may comprise: receiving, from a base station, a first SSB; determining a RACH occasion associated with the first SSB; transmitting, to the base station, a PRACH preamble in the RACH occasion within a first radio resource to which a first SCS is applied; determining a slot to which the RACH occasion belongs based on a reference radio resource to which a reference SCS is applied instead of the first SCS; determining an RNTI for a random access procedure based on a slot index for the slot; and performing a reception operation of a response for the PRACH preamble by using the RNTI in the first radio resource. ## Claims ### Claim 1 An operation method of a terminal in a communication system, the operation method comprising: receiving, from a base station, a first synchronization signal block (SSB); determining a random access channel (RACH) occasion (RO) associated with the first SSB; transmitting, to the base station, a physical random access channel (PRACH) preamble in the RO within a first radio resource to which a first subcarrier spacing (SCS) is applied; determining a position of a slot to which the RO belongs in a reference radio resource to which a reference SCS is applied; determining a radio network temporary identifier (RNTI) for a random access (RA) procedure based on a slot index corresponding to the position of the slot in the reference radio resource; and performing a reception operation of a response for the PRACH preamble by using the RNTI in the first radio resource. ### Claim 2 (depends on 1) The operation method according to claim 1, wherein the first SCS is a 480 kHz SCS or a 960 kHz SCS, the reference SCS is a 120 kHz SCS, and the RNTI is a random access (RA)-RNTI or an MSGB-RNTI. ### Claim 3 (depends on 1) The operation method according to claim 1, wherein one slot in the reference radio resource includes n slots in the first radio resource, the RO is located in one or more slots among the n slots, the slot index used to determine the RNTI is a slot index of the one slot instead of the one or more slots, and n is a natural number equal to or greater than 2. ### Claim 4 (depends on 3) The operation method according to claim 3, wherein a start slot of the RO is limited to a specific slot among the n slots in the first radio resource. ### Claim 5 (depends on 3) The operation method according to claim 3, wherein the one or more slots are located last among the n slots in the first radio resource. ### Claim 6 An operation method of a base station in a communication system, the operation method comprising: transmitting a first synchronization signal block (SSB); receiving, from a terminal, a physical random access channel (PRACH) preamble in a random access channel (RACH) occasion (RO) associated with the first SSB in a first radio resource to which a first subcarrier spacing (SCS) is applied; determining a position of a slot to which the RO belongs in a reference radio resource to which a reference SCS is applied-instead of the first SCS; determining a radio network temporary identifier (RNTI) for a random access (RA) procedure based on a slot index corresponding to the position of the slot in the reference radio resource; and performing a transmission operation of a response for the PRACH preamble by using the RNTI in the first radio resource. ### Claim 7 (depends on 6) The operation method according to claim 6, wherein the first SCS is a 480 kHz SCS or a 960 kHz SCS, the reference SCS is a 120 kHz SCS, and the RNTI is a random access (RA)-RNTI or an MSGB-RNTI. ### Claim 8 (depends on 6) The operation method according to claim 6, wherein one slot in the reference radio resource includes n slots in the first radio resource, the RO is located in one or more slots among the n slots, the slot index used to determine the RNTI is a slot index of the one slot instead of the one or more slots, and n is a natural number equal to or greater than 2. ### Claim 9 (depends on 8) The operation method according to claim 8, wherein a start slot of the RO is limited to a specific slot among the n slots in the first radio resource. ### Claim 10 (depends on 8) The operation method according to claim 8, wherein the one or more slots are located last among the n slots in the first radio resource. ### Claim 11 A terminal in a communication system, the terminal comprising: a processor; a memory electronically communicating with the processor; and instructions stored in the memory, wherein when executed by the processor, the instructions cause the terminal to: receive, from a base station, a first synchronization signal block (SSB); determine an SSB index associated with the first SSB based on a different scheme according to a frequency band in which the base station operates; determine a random access channel (RACH) occasion (RO) associated with the SSB index; and transmit a physical random access channel (PRACH) preamble to the base station in the RO, wherein when the base station operates in a first frequency band, the SSB index is determined based on a first equation or a second equation, and when the base station operates in a second frequency band higher than the first frequency band, the SSB index is determined based on the second equation, the first equation is [an index of a physical broadcast channel (PBCH) demodulation reference signal (DMRS) mod NSSBQCL], the second equation is [an SSB candidate index mod NSSBQCL], the PBCH DMRS is included in the first SSB, the SSB candidate index is associated with the first SSB, and NSSBQCL indicates a number of SSBs having a quasi-co-located (QCL) relation. ### Claim 12 (depends on 11) The terminal according to claim 11, wherein the SSB index associated with the first SSB is an SSB index of a second SSB having a QCL relation with the first SSB.