NR-U Beam Switching After Listen-Before-Talk Channel Access
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Solution Overview
Problem
In 5G new radio on unlicensed spectrum (NR-U), beamforming is not considered during the listen-before-talk (LBT) procedure, leading to inefficient channel access and potential transmission failures due to omni-directional LBT assumptions.
Innovation Solution
Implementing beam switching and panel switching during LBT failures at the user equipment (UE) side, allowing for faster channel access by switching beams or panels autonomously and performing parallel LBT using multiple panels for autonomous uplink (AUL) communications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If omni-directional LBT is used in NR-U Release 16, then the LBT procedure can be implemented without beamforming considerations, but channel access efficiency deteriorates and transmission failures increase
Solution Approach 1:
The patent segments the LBT procedure into two distinct phases: omni-directional LBT for initial channel access, followed by directional LBT for beam-specific transmission. This segmentation allows the system to benefit from both approaches - the simplicity of omni-directional sensing and the efficiency of directional beamforming - by applying each at the appropriate stage of the transmission process
Solution Approach 2:
The patent applies preliminary action by performing omni-directional LBT before directional LBT. This preliminary channel access using omni-directional sensing ensures the channel is available before committing to a specific beam direction, thereby preventing transmission failures while maintaining overall system efficiency
2Device complexity
If omni-directional LBT is used in NR-U Release 16, then beamforming is not required during LBT, but transmission reliability deteriorates due to potential transmission failures
Solution Approach 1:
The patent introduces dynamics by making the LBT approach adaptive - switching from static omni-directional LBT to dynamic directional LBT based on channel conditions and beam availability. This allows the system to adjust its complexity in real-time, using simpler omni-directional sensing when appropriate and more complex directional sensing when transmission reliability requires it
3Speed
If beam switching is implemented during LBT failures, then channel access speed improves, but device complexity increases due to additional beam management
Solution Approach 1:
The patent applies self-service by enabling the UE to autonomously perform beam switching and panel switching when LBT failures occur. The device monitors its own transmission status and automatically initiates beam switching procedures without requiring external intervention, thereby improving channel access speed while managing complexity through autonomous operation
Data Source
AI summary
Apparatuses, methods, and systems are disclosed for beam switching after LBT procedure. One apparatus includes a processor coupled with at least one memory and configured to cause the apparatus to perform a first listen-before-talk (LBT) procedure using omni-directional sensing to acquire a first channel occupancy time (COT); transmit a first transport block (TB) during the first COT based on a successful result of the first LBT procedure, wherein transmission of the first TB uses a first beam and occupies a first portion of the first COT less than an entirety of the first COT; and perform a second LBT procedure using directional sensing to acquire a remaining portion of the first COT.