Directional LBT Beam Selection in Unlicensed Spectrum
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Solution Overview
Problem
Current methods for beam selection in wireless communication networks, particularly in unlicensed spectrum, face challenges such as inefficient channel occupancy and high LBT failure rates, leading to suboptimal performance in random access procedures.
Innovation Solution
The proposed solution involves a user equipment (UE) performing directional listen-before-talk (LBT) procedures in multiple directions to select a beam for random access, considering both reference signal received power (RSRP) and channel occupancy (CO) or LBT failure statistics. The UE selects a beam that meets specific threshold conditions for RSRP and CO or LBT failure metrics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If beam selection is performed based only on RSRP threshold in unlicensed spectrum, then simple selection process is achieved, but LBT failure rate increases and channel occupancy efficiency decreases
Solution Approach 1:
The patent changes the beam selection criteria from a single RSRP parameter to multiple parameters including RSRP, CO metrics, and LBT failure statistics. This multi-parameter approach allows the system to select beams that not only have strong signal quality but also demonstrate successful channel access in unlicensed spectrum, thereby reducing LBT failure rates while maintaining operational feasibility
Solution Approach 2:
The patent implements feedback mechanisms where LBT failure statistics and CO metrics from previous transmissions are collected and used to inform future beam selection decisions. This feedback loop enables the system to learn from past channel access outcomes and adapt beam selection to avoid beams with high failure rates, improving overall reliability
2Reliability
If multiple beam directions are evaluated with multiple metrics, then beam selection reliability improves, but measurement and selection complexity increases
Solution Approach 1:
The patent segments the beam selection process into distinct evaluation stages: first evaluating RSRP thresholds, then assessing CO metrics, and finally considering LBT failure statistics. This segmentation allows the system to systematically process multiple metrics without overwhelming complexity, as each metric is evaluated in a structured sequence rather than simultaneously
Solution Approach 2:
The patent employs dynamic beam selection where the importance and application of different metrics can adapt based on current channel conditions and historical performance. The system dynamically adjusts which metrics are most influential in the selection process, allowing flexibility in managing complexity while maintaining reliability
3Productivity
If directional LBT is performed in multiple directions, then channel access probability improves, but time and computational resources increase
Solution Approach 1:
The patent performs preliminary evaluations of beam directions using RSRP measurements and historical CO/LBT metrics before committing to full directional LBT procedures. By pre-screening beams based on available information, the system reduces the number of directions that require time-consuming full LBT attempts, thus improving channel access probability while minimizing time expenditure
Solution Approach 2:
The patent changes the approach from uniform evaluation of all beam directions to selective evaluation based on multiple parameters including historical performance data. This allows the system to prioritize directions with better historical outcomes and skip or reduce evaluation of directions with poor track records, optimizing the balance between access probability and time consumption
Data Source
AI summary
The invention includes a method performed by a user equipment, UE, for selecting a directional beam for a random access procedure in a wireless network comprising: performing a plurality of directional listen-before-talk, LBT, procedures in a respective plurality of different directions associated with a respective plurality of beams, determining respective first metrics based on received power of respective reference signals associated with the respective beams, determining respective second metrics based on channel occupancy, CO, or LBT failures in the respective beams and selecting one of the beams to be used for the random access procedure based on the first metrics and the second metrics. The invention further includes a complementary method performed by a network node, as well as a UE and a network node configured to perform operations corresponding to such methods.