RACH Occasion Selection Using Retransmission Counter Thresholds

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Solution Overview

Problem

Existing wireless communication systems face inefficiencies in random access channel (RACH) occasion selection, leading to increased latency and waste of signaling resources due to suboptimal selection of RACH occasions without considering retransmission metrics.

Innovation Solution

A user equipment (UE) or network entity selects between different sets of RACH occasions based on a rule, considering retransmission metrics such as a counter threshold, to optimize the selection process.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of time

If traditional RACH occasion selection is used without considering retransmission metrics, then the selection process is simple, but latency increases and signaling resources are wasted

Engineering Contradiction:

ImprovelatencyVSAvoidselection process complexity

Core Design Contradiction:

Loss of timeVSDevice complexity

Solution Approach 1:

The system pre-configures multiple sets of RACH occasions (first set and second set) with different characteristics before retransmission occurs. The UE can then quickly select from these pre-prepared options based on simple counter threshold comparisons, avoiding complex real-time analysis while reducing latency.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The RACH occasion selection becomes dynamic by switching between different configured sets based on retransmission counter thresholds. The UE selects from the first set or second set depending on whether the counter exceeds the threshold, allowing adaptive optimization without permanent system complexity.

Inventive Principle:

Principle #15Dynamics

2Loss of energy

If traditional RACH occasion selection is used without considering retransmission metrics, then the system operation is simple, but signaling resources are wasted

Engineering Contradiction:

Improvesignaling resource wasteVSAvoidoperation simplicity

Core Design Contradiction:

Loss of energyVSEase of operation

Solution Approach 1:

Multiple RACH occasion sets are pre-configured with different resource allocations. By selecting appropriate pre-configured sets based on simple counter comparisons, the system avoids wasteful random signaling attempts while maintaining operational simplicity through threshold-based decision making.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system changes the parameter of RACH occasion selection by introducing counter threshold comparisons. This simple parameter change enables intelligent resource selection that reduces signaling waste without significantly complicating the operation, as the UE only needs to compare counter values against thresholds.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS20250247889A1Random access channel occasion selection

Publication Date: 2025.07.31 QUALCOMM INC

AI summary

Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a user equipment (UE) may receive one or more configurations for a first set of random access channel (RACH) occasions (ROs) and a second set of ROs. The UE may transmit a first transmission in the first set of ROs. The UE may select between the first set of ROs and the second set of ROs based at least in part on a rule. The UE may transmit a retransmission in the selected set of ROs. Numerous other aspects are described.