Resource mapping for random access repetitions using a same spatial filter

Patent metadata

Field	Value
Publication number	US-12356466-B2
Application number	US-202418731211-A
Country	US
Kind code	B2
Filing date	May 31, 2024
Priority date	Apr 6, 2022
Publication date	Jul 8, 2025
Grant date	Jul 8, 2025

Abstract

The described techniques enable repeated physical random access channel (PRACH) preamble transmissions across multiple random access occasions (ROs) using a same spatial filter. A user equipment (UE) may transmit a PRACH preamble across multiple ROs, where each RO is associated with a same synchronization signal block (SSB) or channel state information reference signal (CSI-RS). The PRACH repetitions may be transmitted in ROs in accordance with a first mapping rule: first, in increasing order of frequency resource index; second, in increasing order of a time resource index; third, in increasing order of PRACH slot indices; and fourth, in increasing order of PRACH association period indices. Additionally, or alternatively, the PRACH repetitions may be transmitted in ROs in accordance with a second mapping rule: first, in increasing order of time resource index; second, in increasing order of PRACH slot indices; and third, in increasing order of PRACH association period indices.

First claim

What is claimed is:

1. An apparatus for wireless communications at a user equipment (UE), comprising:
one or more memories; and
one or more processors coupled with the one or more memories and configured to cause the apparatus to:
receive a message indicating a configuration for repeating transmissions of a first random access message of a random access procedure;
select a set of random access occasions for a quantity of repetitions of the first random access message in accordance with the configuration and a mapping rule, wherein:
the set of random access occasions is based at least in part on an association between the set of random access occasions and one or more synchronization signal blocks,
the mapping rule is based at least in part on resources associated with each random access occasion of the set of random access occasions,
a first valid random access occasion of the set of random access occasions is determined in accordance with the mapping rule comprising an ordering of valid random access occasions within a time period, the ordering comprising first, in increasing order of frequency resource index for frequency multiplexed random access occasions, and second, in increasing order of a time resource index for time multiplexed random access occasions, and
respective random access occasions of the set of random access occasions are non-overlapping in time; and

transmit the quantity of repetitions of the first random access message using a same spatial filter via the set of random access occasions.

2. The apparatus of claim 1 , wherein, to select the set of random access occasions in accordance with the mapping rule, the one or more processors are further configured to cause the apparatus to:
identify a channel state information reference signal, a synchronization signal block from a set of synchronization signal blocks, or both; and
select the set of random access occasions based at least in part on an association between the set of random access occasions, the synchronization signal block, the channel state information reference signal, or a combination thereof.

3. The apparatus of claim 2 , wherein, to select the set of random access occasions in accordance with the mapping rule, the one or more processors are further configured to cause the apparatus to:
select one or more first random access occasions based at least in part on a respective frequency-domain index of the resources associated with each random access occasion of the set of random access occasions.

4. The apparatus of claim 3 , wherein, to select the set of random access occasions in accordance with the mapping rule, the one or more processors are further configured to cause the apparatus to:
select one or more second random access occasions based at least in part on a respective time-domain index of the resources associated with each random access occasion of the set of random access occasions, the one or more second random access occasions being included in a same slot.

5. The apparatus of claim 4 , wherein, to select the set of random access occasions in accordance with the mapping rule, the one or more processors are further configured to cause the apparatus to:
select one or more third random access occasions based at least in part on a respective slot index of the resources associated with each random access occasion of the set of random access occasions.

6. The apparatus of claim 5 , wherein, to select the set of random access occasions in accordance with the mapping rule, the one or more processors are further configured to cause the apparatus to:
select one or more fourth random access occasions based at least in part on a respective association period index of the resources associated with each random access occasion of the set of random access occasions.

7. The apparatus of claim 1 , wherein, to select the set of random access occasions in accordance with the mapping rule, the one or more processors are further configured to cause the apparatus to:
select one or more first random access occasions based at least in part on a respective time-domain index of the resources associated with each random access occasion of the set of random access occasions, the one or more first random access occasions being included in a same slot.

8. The apparatus of claim 7 , wherein, to select the set of random access occasions in accordance with the mapping rule, the one or more processors are further configured to cause the apparatus to:
select one or more second random access occasions based at least in part on a respective slot index of the resources associated with each random access occasion of the set of random access occasions.

9. The apparatus of claim 8 , wherein, to select the set of random access occasions in accordance with the mapping rule, the one or more processors are further configured to cause the apparatus to:
select one or more third random access occasions based at least in part on a respective association period index of the resources associated with each random access occasion of the set of random access occasions.

10. The apparatus of claim 1 , wherein the one or more processors are further configured to cause the apparatus to:
identify the quantity of repetitions of the first random access message based at least in part on the configuration, wherein the quantity of repetitions of the first random access message is the same as a quantity of possible retransmissions of the first random access message.

11. The apparatus of claim 1 , wherein the one or more processors are further configured to cause the apparatus to:
identify the quantity of repetitions of the first random access message based at least in part on the configuration, wherein the quantity of repetitions of the first random access message is different than a quantity of possible retransmissions of the first random access message.

12. The apparatus of claim 1 , wherein the mapping rule comprises a first mapping rule for respective random access occasions of the set of random access occasions that overlap in time or a second mapping rule for the respective random access occasions of the set of random access occasions that are non-overlapping in time, and the one or more processors are further configured to cause the apparatus to:
receive a second message configuring the UE with the first mapping rule or the second mapping rule.

13. The apparatus of claim 12 , wherein the message comprises a radio resource control message or a system information message, or any combination thereof.

14. The apparatus of claim 1 , wherein, to transmit the quantity of repetitions of the first random access message, the one or more processors are further configured to cause the apparatus to:
transmit the quantity of repetitions of the first random access message across two or more association patterns based at least in part on a quantity of random access occasions in the set of random access occasions.

15. The apparatus of claim 1 , wherein, to transmit the quantity of repetitions of the first random access message, the one or more processors are further configured to cause the apparatus to:
transmit an initial portion of the quantity of repetitions of the first random access message during a current association pattern based at least in part on a quantity of random access occasions in the set of random access occasions; and
stop transmission of a remaining portion of the quantity of repetitions of the first random access message after the current association pattern ends.

16. The apparatus of claim 1 , wherein the quantity of repetitio

Assignees

• Qualcomm Inc

Inventors

• Ly Hung Dinh
• Xiao Kexin
• Kwon Hwan Joon

Classifications

• H04W74/0836

  with 2-step access · CPC title

• H04W72/0446

  Resources in time domain, e.g. slots or frames · CPC title

• H04W74/0833 Primary

  Random access procedures, e.g. with 4-step access · CPC title

• H04W74/0891

  for synchronized access · CPC title

• H04B7/0626 Primary

  Channel coefficients, e.g. channel state information [CSI] · CPC title