# US 10,484,151 B2 · Controlling random-access channel (RACH) retransmissions for wireless communication > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,484,151 B2 - Document ID: US10484151B2 - Status: Granted - Kind: B2 - Application number: 15/892,690 - Filed: 2018-02-09 - Published: 2018-09-06 - Granted: 2019-11-19 - Earliest claimed: 2017-03-02 - Assignees: QUALCOMM Incorporated - Applicants: QUALCOMM Incorporated - Inventors: Muhammad Nazmul Islam; Tao Luo; Junyi Li - Web page: https://patentgrep.com/patent/US10484151B2 ## CPC - H04L 1/189: {Transmission or retransmission of more than one copy of a message} - H04W 72/0446: Resources in time domain, e.g. slots or frames - H04W 72/542: using measured or perceived quality - H04W 74/0833: Random access procedures, e.g. with 4-step access - H04W 72/046: {the resource being in the space domain, e.g. beams} - H04W 74/0838: using contention-free random access [CFRA] - 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 Various aspects of the disclosure provide for methods of communication. One method, at a base station, involves determining a maximum number of consecutive MSG1 retransmissions that a user equipment (UE) is permitted to perform, and transmitting the maximum number of consecutive MSG1 retransmissions to the UE. Another method involves receiving a maximum number of consecutive MSG1 retransmissions to be performed, and transmitting consecutive MSG1 retransmission signals for the maximum number of times. ## Claims ### Claim 1 A method of communication at a base station, comprising: determining a maximum number of consecutive MSG1 retransmissions that a user equipment (UE) is permitted to perform; transmitting information indicating the maximum number of consecutive MSG1 retransmissions to the UE; receiving, before a random access response (RAR) window, a consecutive MSG1 retransmission from the UE; and repeating the receiving, after the RAR window, one or more subsequent consecutive MSG1 retransmissions from the UE until the maximum number of consecutive MSG1 retransmissions has been received, wherein each subsequent consecutive MSG1 retransmission is received after a corresponding RAR window. ### Claim 2 (depends on 1) The method of claim 1, further comprising: receiving a first number of consecutive MSG1 retransmissions from the UE, wherein the first number is equal to the maximum number; determining a random backoff period for a next MSG1 retransmission at the UE; transmitting the random backoff period to the UE; and receiving the next MSG1 retransmission in accordance with the random backoff period. ### Claim 3 (depends on 1) The method of claim 1, further comprising: transmitting an indication as to whether the UE is permitted to transmit with different transmit beams during consecutive MSG1 retransmissions. ### Claim 4 (depends on 3) The method of claim 3, further comprising: receiving a first number of consecutive MSG1 retransmissions from the UE; and transmitting to the UE an indication of a highest quality transmit beam among possible transmit beams. ### Claim 5 (depends on 1) The method of claim 1, further comprising: transmitting an indication to the UE to transmit with a same preamble and a same resource during consecutive MSG1 retransmissions. ### Claim 6 (depends on 1) The method of claim 1, further comprising: combining signals of two or more consecutive MSG1 retransmissions to decode a random access channel (RACH) signal, wherein the combining the signals of the consecutive MSG1 retransmissions comprises non-coherently adding power of the signals of the consecutive MSG1 retransmissions. ### Claim 7 A method of communication at a user equipment (UE), comprising: receiving information indicating a maximum number of consecutive MSG1 retransmissions to be performed; and transmitting consecutive MSG1 retransmission signals for the maximum number of times, wherein the transmitting consecutive MSG1 retransmission signals comprises: transmitting, before a random access response (RAR) window, a consecutive MSG1 retransmission, and repeating the transmitting, after the RAR window, one or more subsequent consecutive MSG1 retransmissions until the maximum number of consecutive MSG1 retransmissions has been transmitted, wherein each subsequent consecutive MSG1 retransmission is transmitted after a corresponding RAR window. ### Claim 8 (depends on 7) The method of claim 7, further comprising: receiving a random backoff period for a next MSG1 retransmission; and transmitting a MSG1 retransmission signal in accordance with the random backoff period. ### Claim 9 (depends on 7) The method of claim 7, further comprising: receiving an authorization to transmit with different transmit beams during consecutive MSG1 retransmissions; and transmitting consecutive MSG1 retransmission signals with different transmit beams. ### Claim 10 (depends on 9) The method of claim 9, further comprising: receiving an indication of a highest quality transmit beam among possible transmit beams; and transmitting consecutive MSG1 retransmission signals with the highest quality transmit beam. ### Claim 11 (depends on 7) The method of claim 7, further comprising: receiving an indication to transmit with a same preamble and a same resource during consecutive MSG1 retransmissions; and transmitting consecutive MSG1 retransmission signals with a same preamble and a same resource. ### Claim 12 An apparatus for communication, comprising: a memory device; and a processing circuit coupled to the memory device and configured to: determine a maximum number of consecutive MSG1 retransmissions that a user equipment (UE) is permitted to perform, transmit information indicating the maximum number of consecutive MSG1 retransmissions to the UE, receive, before a random access response (RAR) window, a consecutive MSG1 retransmission from the UE, and repeatedly receive, after the RAR window, one or more subsequent consecutive MSG1 retransmissions from the UE until the maximum number of consecutive MSG1 retransmissions has been received, wherein each subsequent consecutive MSG1 retransmission is received after a corresponding RAR window. ### Claim 13 (depends on 12) The apparatus of claim 12, wherein the processing circuit is further configured to: receive a first number of consecutive MSG1 retransmissions from the UE, wherein the first number is equal to the maximum number; determine a random backoff period for a next MSG1 retransmission at the UE; transmit the random backoff period to the UE; and receive the next MSG1 retransmission in accordance with the random backoff period. ### Claim 14 (depends on 12) The apparatus of claim 12, wherein the processing circuit is further configured to: transmit an indication as to whether the UE is permitted to transmit with different transmit beams during consecutive MSG1 retransmissions. ### Claim 15 (depends on 14) The apparatus of claim 14, wherein the processing circuit is further configured to: receive a first number of consecutive MSG1 retransmissions from the UE; and transmit to the UE an indication of a highest quality transmit beam among possible transmit beams. ### Claim 16 (depends on 12) The apparatus of claim 12, wherein the processing circuit is further configured to: transmit an indication to the UE to transmit with a same preamble and a same resource during consecutive MSG1 retransmissions. ### Claim 17 (depends on 12) The apparatus of claim 12, wherein the processing circuit is further configured to: combine signals of two or more consecutive MSG1 retransmissions to decode a random access channel (RACH) signal; and non-coherently add power of the signals of the consecutive MSG1 retransmissions to decode the RACH signal. ### Claim 18 An apparatus for communication, comprising: a memory device; and a processing circuit coupled to the memory device and configured to: receive information indicating a maximum number of consecutive MSG1 retransmissions to be performed, transmit consecutive MSG1 retransmission signals for the maximum number of times, wherein the processing circuit configured to transmit is further configured to: transmit, before a random access response (RAR) window, a consecutive MSG1 retransmission, and repeatedly transmit, after the RAR window, one or more subsequent consecutive MSG1 retransmissions until the maximum number of consecutive MSG1 retransmissions has been transmitted, wherein each subsequent consecutive MSG1 retransmission is transmitted after a corresponding RAR window. ### Claim 19 (depends on 18) The apparatus of claim 18, wherein the processing circuit is further configured to: receive a random backoff period for a next MSG1 retransmission; and transmit a MSG1 retransmission signal in accordance with the random backoff period. ### Claim 20 (depends on 18) The apparatus of claim 18, wherein the processing circuit is further configured to: receive an authorization to transmit with different transmit beams during consecutive MSG1 retransmissions; and transmit consecutive MSG1 retransmission signals with different transmit beams. ### Claim 21 (depends on 20) The apparatus of claim 20, wherein the processing circuit is further configured to: receive an indication of a highest quality transmit beam among possible transmit beams; and transmit consecutive MSG1 retransmission signals with the highest quality transmit beam. ### Claim 22 (depends on 18) The apparatus of claim 18, wherein the processing circuit is further configured to: receive an indication to transmit with a same preamble and a same resource during consecutive MSG1 retransmissions; and transmit consecutive MSG1 retransmission signals with a same preamble and a same resource.