Adaptive Event Timer for NR-U LBT Failure Handling
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Solution Overview
Problem
In wireless communication networks, especially in contention-based and shared spectrum technologies like NR-U and NR-SS, there is uncertainty in transmission due to the possibility of Listen Before Talk (LBT) failure, leading to inefficiencies and increased timer values to account for these uncertainties, which can result in increased transmission inefficiencies.
Innovation Solution
Implementing an event timer that can be suspended during periods of failed LBT procedures by user equipment (UE) and resumed upon successful LBT completion, allowing for optimized timer configurations that maintain shorter timer lengths without uniformly increasing them.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If timer values are uniformly increased to account for LBT failure uncertainty, then transmission reliability is improved, but transmission efficiency deteriorates due to unnecessary delays
Solution Approach 1:
The patent applies dynamics by making the timer configuration adaptive rather than static. The network device dynamically adjusts the timer value based on the actual LBT procedure configuration (first LBT or second LBT) and suspends or resumes the timer based on LBT success or failure. This dynamic approach allows the system to maintain shorter timers when LBT is likely to succeed while extending them when LBT failure is possible, thus resolving the contradiction between reliability and delay.
Solution Approach 2:
The patent changes the timer parameter based on different LBT procedure configurations and outcomes. Instead of using a fixed timer value, the system adjusts the timer configuration parameter according to whether the first LBT procedure succeeds or fails, and whether a second LBT procedure is performed. This parameter adaptation allows optimal timer values to be selected for different transmission scenarios, improving reliability without incurring unnecessary delays.
2Productivity
If shorter timer values are used to improve transmission efficiency, then transmission efficiency is improved, but transmission reliability deteriorates due to timer expiration before successful transmission
Solution Approach 1:
The patent makes the timer configuration dynamic by linking it to the actual LBT procedure outcomes. When the first LBT procedure succeeds, the timer is configured for shorter duration to improve efficiency. When the first LBT fails or a second LBT is performed, the timer is extended or suspended to ensure reliability. This dynamic adaptation resolves the contradiction by allowing short timers only when appropriate.
Solution Approach 2:
The system uses feedback from LBT procedure results to adjust timer configuration. The network device monitors whether LBT procedures succeed or fail and uses this feedback information to configure appropriate timer values. This feedback mechanism ensures that timer values are always appropriate for the current transmission conditions, maintaining both efficiency and reliability.
3Productivity
If timer is suspended during failed LBT procedures, then transmission efficiency is improved by preventing unnecessary delays, but system complexity increases due to timer management overhead
Solution Approach 1:
The patent applies dynamics by making the timer suspension and resumption behavior dependent on the actual LBT procedure configuration and outcomes. The system dynamically determines whether to suspend or continue the timer based on whether the first LBT succeeds, fails, or requires a second LBT. This dynamic approach improves efficiency by suspending timers only when appropriate while maintaining manageable complexity through clear suspension/resumption rules.
Data Source
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AI summary
Timer configurations for new radio (NR) unlicensed (NR-U) and NR shared spectrum (NR-SS) operations are disclosed. In NR-U and NR-SS operations, certain event timers may be interrupted by a user equipment (UE) when it detects that its serving base station has failed a listen before talk (LBT) procedure, thereby losing access to the shared communication spectrum. When the UE detects a subsequent successful LBT, it resumes the progression of the event timer. In NR-SS operations, the UE may also interrupt the applicable timers either in all slots dedicated to another operator or in all slots in which the serving base station does not have transmission access.