SSB Selection and LBT Optimization for Wireless Random Access

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Solution Overview

Problem

Existing wireless communication systems face inefficiencies in performing random access procedures, particularly in unlicensed bands, due to challenges in channel access and resource allocation.

Innovation Solution

The method involves a communication device that detects synchronization signal blocks (SSBs), selects suitable SSBs, performs listen-before-talk (LBT) for specific random access channel occasions (ROs), and transmits a physical random access channel (PRACH) in successfully cleared ROs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If listen-before-talk (LBT) is performed for multiple random access channel occasions (ROs), then channel access reliability is improved, but access latency increases

Engineering Contradiction:

Improvechannel access success rateVSAvoidaccess latency

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The communication device performs LBT in advance for multiple ROs associated with selected SSBs before actually transmitting the PRACH. By pre-performing the LBT check and caching the results, the device avoids repeating LBT operations, thereby improving channel access reliability while reducing the actual access latency when transmission is needed.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The device dynamically selects which ROs to perform LBT based on SSB measurement results and channel conditions. By adaptively adjusting the set of ROs for LBT based on current system state, the device optimizes the balance between access reliability and latency.

Inventive Principle:

Principle #15Dynamics

2Reliability

If multiple SSBs are selected for LBT, then random access reliability is improved, but signaling overhead and processing complexity increase

Engineering Contradiction:

Improverandom access reliabilityVSAvoidprocessing complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The device performs LBT selectively for specific ROs associated with SSBs that have been selected based on RSRP threshold criteria. By focusing LBT operations only on the most promising SSBs rather than all detected SSBs, the device improves access reliability while limiting processing complexity to only the necessary subset of operations.

Inventive Principle:

Principle #3Local quality

3Reliability

If LBT is performed for all detected SSBs, then channel access reliability is maximized, but energy consumption increases

Engineering Contradiction:

Improvechannel access reliabilityVSAvoidenergy consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The device changes the parameter of SSB selection by introducing RSRP threshold filtering. Only SSBs meeting the threshold criteria are selected for LBT, which reduces the number of LBT operations and associated energy consumption while maintaining adequate access reliability through selective targeting of the strongest signals.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS12219618B2Method and apparatus for transmitting and receiving signal in wireless communication system

Publication Date: 2025.02.04 LG ELECTRONICS INC

AI summary

A method and an apparatus for transmitting and receiving a signal in a wireless communication system, according to one embodiment of the present invention, are characterized by detecting one or more SSBs, selecting some SSBs from among the detected SSBs, and transmitting PRAM through an RO which succeeds in LBT, among ROs corresponding to the selected SSBs.