Beam-Based LBT Channel Access for Reliable Uplink Transmission
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Solution Overview
Problem
Existing wireless communication systems face challenges in efficiently performing channel access procedures, particularly in scenarios requiring enhanced broadband, ultra-reliability, and low-latency communications, due to limitations in listen-before-talk (LBT) mechanisms.
Innovation Solution
Implementing a method and apparatus that utilize first and second LBT processes based on specific beams and beam groups, with adjustable energy detection thresholds and contention window sizes, allowing for independent configuration of backoff counter values to optimize channel access.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If first LBT is performed based on a specific beam with a smaller ED threshold, then channel access reliability is improved, but channel access time increases due to potential failure requiring second LBT
Solution Approach 1:
The channel access procedure is segmented into two distinct LBT stages: first LBT based on a specific beam with a first ED threshold, and second LBT based on a beam group with a second ED threshold. This segmentation allows the system to first attempt efficient beam-specific access, and only if that fails, proceed to the more comprehensive beam group access, thereby balancing reliability and time loss.
Solution Approach 2:
The first LBT based on a specific beam serves as a preliminary action before the second LBT based on a beam group. By performing the specific beam LBT first with a lower threshold, the system can quickly gain channel access when conditions are favorable, avoiding the time-consuming second LBT stage and reducing overall channel access time while maintaining reliability.
2Adaptability or versatility
If independent CWS and backoff counter configuration is used for first and second LBT, then adaptability is improved, but device complexity increases
Solution Approach 1:
The system dynamically configures LBT parameters based on the LBT stage. For the first LBT based on a specific beam, independent CWS and backoff counter values can be configured to optimize performance for targeted beam access. For the second LBT based on a beam group, different independent parameters are configured to accommodate the broader access scenario. This dynamic configuration approach provides adaptability while managing complexity through stage-specific parameter sets.
Data Source
AI summary
The present disclosure provides a method for transmitting an uplink signal by a terminal in a wireless communication system. In particular, the method may comprise: performing a first listen-before-talk (LBT) on the basis of a specific beam; on the basis of the failure of the first LBT, performing a second LBT on the basis of a beam group including the specific beam; and transmitting the uplink signal on the basis of the success of the second LBT, wherein a first energy detection (ED) threshold value for the first LBT is less than or equal to a second ED threshold value for the second LBT.