# US 12,010,733 B2 · Terminal apparatus, base station apparatus, control method, and computer-readable storage medium for executing random access procedure > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,010,733 B2 - Document ID: US12010733B2 - Status: Granted - Kind: B2 - Application number: 17/397,030 - Filed: 2021-08-09 - Published: 2021-12-16 - Granted: 2024-06-11 - Earliest claimed: 2019-02-13 - Assignees: Kddi Corporation - Applicants: Kddi Corporation - Inventors: Takeo Ohseki; Issei Kanno; Yasuhiro Suegara; Masahito Umehara - Web page: https://patentgrep.com/patent/US12010733B2 ## CPC - H04W 74/0841: {with collision treatment} - H04W 72/044: based on the type of the allocated resource - H04W 74/0836: with 2-step access - H04W 76/10: Connection setup - H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72) ## Abstract A terminal apparatus, which executes a two-step random access procedure or a four-step random access procedure to establish a connection with a base station apparatus, executes control such that, in a case where a first message of the two-step random access procedure including a preamble and predetermined information for connection establishment is transmitted and a number of unsuccessful attempts to receive the first message by the base station apparatus exceeds a predetermined number, the terminal apparatus transmits a second message to be transmitted from the terminal apparatus to the base station apparatus in the four-step random access procedure. ## Claims ### Claim 1 A terminal apparatus that executes a two-step random access procedure or a four-step random access procedure to establish a connection with a base station apparatus, comprising: one or more processors; and one or more memories that stores computer-readable instruction for causing, when executed by the one or more processors, the terminal apparatus to: transmit a first message of the two-step random access procedure including a preamble and predetermined information for connection establishment; and transmit, in a case where a number of unsuccessful attempts to receive the first message by the base station apparatus exceeds a predetermined number, a second message to be transmitted from the terminal apparatus to the base station apparatus in the four-step random access procedure, wherein communication between the base station apparatus and the terminal apparatus is performed using at least one of a plurality of bandwidth parts included in a usable frequency band, the predetermined number is set for each one of the plurality of bandwidth parts, and in a case where the number exceeds the predetermined number set for one bandwidth part used to transmit the first message from among the plurality of bandwidth parts, the terminal apparatus transmits the second message. ### Claim 2 (depends on 1) The terminal apparatus according to claim 1, wherein the predetermined number is a maximum number of transmission attempts of a random access preamble in a four-step random access procedure. ### Claim 3 (depends on 1) The terminal apparatus according to claim 1, wherein the predetermined number is a number different from a maximum number of transmission attempts of a random access preamble in a four-step random access procedure. ### Claim 4 (depends on 1) The terminal apparatus according to claim 1, wherein the terminal apparatus transmits the second message in response to receiving an instruction transmitted from the base station apparatus in response to the number exceeding the predetermined number. ### Claim 5 (depends on 1) The terminal apparatus according to claim 1, wherein the second message is a preamble transmitted via the first message. ### Claim 6 (depends on 1) The terminal apparatus according to claim 1, wherein the second message is a preamble different from a preamble transmitted via the first message. ### Claim 7 (depends on 4) The terminal apparatus according to claim 4, wherein the second message is a message transmitted after a random access response in the four-step random access procedure. ### Claim 8 (depends on 4) The terminal apparatus according to claim 4, wherein the instruction is included in a reply message to the first message in the two-step random access procedure. ### Claim 9 (depends on 8) The terminal apparatus according to claim 8, wherein the instruction is reported to the terminal apparatus by using first identification information in transmission of a first portion of the reply message; and the first identification information is different from second identification information used in transmission of the first portion via the reply message in a case where the first message is successfully received. ### Claim 10 (depends on 8) The terminal apparatus according to claim 8, wherein the instruction is reported to the terminal apparatus by transmitting first information via a second portion of the reply message; and the first information is different from second information transmitted via the second portion via the reply message in a case where the first message is successfully received. ### Claim 11 (depends on 10) The terminal apparatus according to claim 10, wherein the first information is information corresponding a random access response in the four-step random access procedure. ### Claim 12 A base station apparatus, comprising: one or more processors; and one or more memories that stores computer-readable instruction for causing, when executed by the one or more processors, the base station apparatus to report a predetermined number to a terminal apparatus such that the terminal apparatus transmits, in a case where the number of unsuccessful attempts to receive a first message transmitted from the terminal apparatus including a preamble and predetermined information for connection establishment of a two-step random access procedure exceeds a predetermined number, a second message to be transmitted in a four-step random access procedure, wherein communication between the base station apparatus and the terminal apparatus is performed using at least one of a plurality of bandwidth parts included in a usable frequency band, the predetermined number is set for each one of the plurality of bandwidth parts, and in a case where the number exceeds the predetermined number set for one bandwidth part used to transmit the first message from among the plurality of bandwidth parts, the terminal apparatus transmits the second message. ### Claim 13 (depends on 12) The base station apparatus according to claim 12, wherein the second message is a random access preamble in the four-step random access procedure. ### Claim 14 (depends on 12) The base station apparatus according to claim 12, wherein in a case where, for the first message, the preamble is detected but a number of unsuccessful attempts to receive the predetermined information exceeds the predetermined number, the base station apparatus transmits to the terminal apparatus a message instructing the terminal apparatus to transmit the second message. ### Claim 15 (depends on 14) The base station apparatus according to claim 14, wherein the second message is a message transmitted after a random access response in the four-step random access procedure. ### Claim 16 A control method executed by a terminal apparatus capable of executing a two-step random access procedure or a four-step random access procedure to establish a connection with a base station apparatus, the control method comprising: transmitting a first message of the two-step random access procedure including a preamble and predetermined information for connection establishment; and transmitting, in a case where a number of unsuccessful attempts to receive the first message by the base station apparatus exceeds a predetermined number, a second message to be transmitted from the terminal apparatus to the base station apparatus in the four-step random access procedure; wherein communication between the base station apparatus and the terminal apparatus is performed using at least one of a plurality of bandwidth parts included in a usable frequency band, the predetermined number is set for each one of the plurality of bandwidth parts, and in a case where the number exceeds the predetermined number set for one bandwidth part used to transmit the first message from among the plurality of bandwidth parts, the terminal apparatus transmits the second message. ### Claim 17 A non-transitory computer-readable storage medium that stores a program for causing a computer, provided in a terminal apparatus capable of executing a two-step random access procedure or a four-step random access procedure to establish a connection with a base station apparatus, comprising: transmitting a first message of the two-step random access procedure including a preamble and predetermined information for connection establishment and transmitting in a case where a number of unsuccessful attempts to receive the first message by the base station apparatus exceeds a predetermined number, a second message to be transmitted from the terminal apparatus to the base station apparatus in the four-step random access procedure, wherein communication between the base station apparatus and the terminal apparatus is performed using at least one of a plurality of bandwidth parts included in a usable frequency band, the predetermined number is set for each one of the plurality of bandwidth parts, and in a case where the number exceeds the predetermined number set for one bandwidth part used to transmit the first message from among the plurality of bandwidth parts, the terminal apparatus transmits the second message.