Directional UL LBT Failure Handling in NR-U
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Solution Overview
Problem
Current wireless communication technologies, particularly in the NR-U (New Radio-Unlicensed) spectrum, face inefficiencies in handling directional LBT (Listen Before Talk) failures, which can lead to service interruptions and poor channel access probabilities due to the lack of support for directional LBT mechanisms beyond the 52.6 GHz frequency range.
Innovation Solution
Implementing a method where wireless devices detect LBT failures on serving transmission beams and send failure reports to access nodes, allowing for the selection of new beams to mitigate consistent directional LBT failures, enabling autonomous switching and improved channel access by maintaining beam-specific counters and timers for UL directional LBT failures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If directional LBT mechanisms are implemented beyond 52.6 GHz frequency range, then channel access probability improves, but device complexity increases due to beam-specific counter and timer management
Solution Approach 1:
The patent segments the LBT failure handling by introducing beam-specific counters and timers for each transmission beam. This allows independent tracking of LBT failures per beam, enabling targeted beam switching decisions without managing complexity across the entire system. Each beam maintains its own failure count and timer state, isolating the complexity to manageable per-beam units.
Solution Approach 2:
The patent implements preliminary action by pre-configuring beam-specific counters and timers before LBT operations begin. The system prepares beam failure detection mechanisms in advance, so when LBT failures occur, the switching decision can be made quickly based on pre-established criteria rather than computing decisions in real-time during failure events.
2Reliability
If autonomous beam switching is implemented to mitigate directional LBT failures, then service interruption is reduced, but control overhead increases due to failure reporting and switching coordination
Solution Approach 1:
The patent implements self-service by enabling the wireless device to autonomously detect beam failures and switch to alternative beams without requiring network coordination for each switching event. The device independently monitors its own beam performance, detects failures based on beam-specific counter thresholds, and performs switching autonomously, thereby reducing control overhead and preventing service interruptions.
Solution Approach 2:
The patent uses feedback mechanisms where the wireless device reports beam failure information to the access node based on beam-specific counter values. This feedback allows the network to awareness of beam conditions while enabling autonomous switching decisions at the device level, balancing control overhead with service continuity.
3Reliability
If beam-specific LBT failure detection is implemented, then directional LBT failure handling improves, but processing time increases due to per-beam monitoring and evaluation
Solution Approach 1:
The patent implements periodic action through beam-specific timers that periodically check and reset failure counters. Instead of continuous monitoring, the system uses timer-based periodic evaluation of beam failure conditions, which reduces processing time while maintaining detection accuracy. The timers create regular checking intervals that balance timely failure detection with reduced computational burden.
Data Source
AI summary
A wireless device (10) sends LBT (listen before talk) based uplink wireless transmissions on a serving transmission beam (22) to an access node (100-1, 100-2). The serving transmission beam (22) is selected from a plurality of transmission beams (21, 22, 23). Further, the wireless device (10) detects LBT failures on the serving transmission beam (22). Based on the number of the detected LBT failures on the serving transmission beam (22), the wireless device (10) sends a failure report to the access node (100-1, 100-2. The failure report indicates the detected LBT failures on the sewing transmission beam (22).