US 12,262,420 B2
Systems and methods for latency reduction for 2-step random access channel (RACH) hybrid automatic repeat requests (HARQ)
Jing Lei, San Diego, CA (US); Muhammad Nazmul Islam, Littleton, MA (US); Linhai He, San Diego, CA (US); Amir Aminzadeh Gohari, Santa Clara, CA (US); Yuanning Yu, Santa Clara, CA (US); Enoch Shiao-Kuang Lu, San Diego, CA (US); Yi Huang, San Diego, CA (US); Ruiming Zheng, Beijing (CN); and Wanshi Chen, San Diego, CA (US)
Assigned to QUALCOMM Incorporated, San Diego, CA (US)
Appl. No. 17/754,465
Filed by QUALCOMM Incorporated, San Diego, CA (US)
PCT Filed Oct. 2, 2019, PCT No. PCT/CN2019/109800
§ 371(c)(1), (2) Date Apr. 1, 2022,
PCT Pub. No. WO2021/062864, PCT Pub. Date Apr. 8, 2021.
Prior Publication US 2022/0377801 A1, Nov. 24, 2022
Int. Cl. H04W 74/08 (2024.01); H04W 74/00 (2009.01); H04W 74/0833 (2024.01)
CPC H04W 74/0833 (2013.01) [H04W 74/006 (2013.01)] 35 Claims
OG exemplary drawing
 
1. A method of wireless communication, comprising:
receiving, by a user equipment (UE) from a base station (BS), system information for initiating a random access channel (RACH) procedure;
transmitting, by the UE to the BS, a first message including a random access preamble and a first payload of a connection request;
monitoring, by the UE from the BS, for a second message in response to the first message during a random access response (RAR) window;
re-transmitting, by the UE to the BS, the first message in response to determining based on the monitoring that no second message is received by the UE from the BS within the RAR window;
re-transmitting, by the UE, the first payload to the BS in response to determining that the second message is received by the UE from the BS within the RAR window, and that a second payload decoded from the second message indicates a fallback response; and
transmitting, by the UE, an acknowledgement message to the BS in response to determining that the second message is received by the UE from the BS within the RAR window and that the second payload indicates a success response.