Sidelink Unicast RLF Detection Through All-Resource LBT Checks
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Solution Overview
Problem
Current methods for determining radio link failure (RLF) on a unicast connection on a sidelink are inadequate, leading to unreliable SL transmissions and compromised communication quality due to insufficient coverage of application scenarios.
Innovation Solution
A terminal device performs listen before talk (LBT) on all resources of a unicast connection and determines RLF based on consistent LBT failures across these resources, thereby discontinuing data transmission to ensure reliable communication.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional RLF determination methods (RLC retransmission maximum, T400 timer expiry, HARQ DTX maximum, PDCP integrity check failure) are used to determine RLF on unicast connection, then the determination process is simple, but the coverage of application scenarios is insufficient leading to unreliable SL transmissions
Solution Approach 1:
The patent segments the RLF determination process into multiple independent criteria: LBT failure detection, RLC retransmission maximum, T400 timer expiry, HARQ DTX maximum, and PDCP integrity check failure. Each criterion operates independently and can trigger RLF determination separately, allowing comprehensive scenario coverage while maintaining modular simplicity in each individual check.
Solution Approach 2:
The patent applies partial action by introducing LBT failure detection as an additional RLF criterion without requiring all traditional criteria to be simultaneously satisfied. This excessive action (adding more determination criteria) ensures that RLF can be detected in broader scenarios including cases where traditional methods fail, thereby improving reliability without requiring complete overhaul of existing simple determination mechanisms.
2Reliability
If LBT is performed on all resources and RLF is determined based on consistent LBT failures, then unreliable SL transmissions are reduced, but the complexity of resource management increases
Solution Approach 1:
The patent performs LBT (Listen Before Talk) on all resources before actual data transmission occurs. This preliminary action allows the system to detect potential RLF conditions in advance by checking for consistent LBT failures across resources, preventing unreliable transmissions before they happen rather than reacting after failures occur.
Solution Approach 2:
The patent implements feedback mechanisms where LBT failure results from each resource are collected and analyzed. When consistent LBT failures are detected across multiple resources, this feedback triggers RLF determination and subsequent actions such as releasing bearers and discarding configuration information, creating a closed-loop system that adapts to channel conditions.
3Productivity
If data transmission continues without accurate RLF detection, then transmission productivity is maintained, but communication quality deteriorates due to unreliable transmissions
Solution Approach 1:
The patent uses feedback from LBT results and traditional RLF indicators to continuously monitor connection health. When RLF is determined through any criterion including LBT failures, the system immediately stops data transmission on affected bearers, preventing further unreliable transmissions while maintaining productivity on healthy connections through selective resource management.
Solution Approach 2:
Upon RLF determination, the patent discards corrupted configuration information and releases affected bearers to stop unreliable transmissions. This discarding action prevents further degradation of communication quality, while the system can recover by re-establishing connections and allocating new resources, thereby restoring productivity with improved reliability.
Data Source
AI summary
This application provides a communication method and apparatus. A first terminal device performs LBT on any resource in all resources on a first unicast connection, and may determine, when consistent LBT failures occur on all the resources on the first unicast connection, that an RLF occurs on the first unicast connection. This increases a manner of determining that an RLF occurs on a unicast connection. In addition, the first terminal device does not continue to perform data transmission on the unicast connection, so that unreliable SL transmissions can be reduced, and quality of SL unicast communication is ensured.