Sidelink Relay Recovery Using HARQ-ACK Threshold Relay Switching
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Solution Overview
Problem
Existing methods are inadequate for efficiently recovering radio link failures (RLFs) in sidelink relay communication, particularly in 5G New Radio (NR) systems, which can disrupt Vehicle-to-Everything (V2X) communications.
Innovation Solution
A method for a transmitting terminal to declare RLF based on HARQ-ACK reception failures and switch to a second relay terminal, with preconfigured conditions received from a base station, and a relay terminal to transmit an RLF message when HARQ-ACK thresholds are exceeded, enabling connection reconfiguration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If relay communication is used to extend coverage, then communication reach is improved, but link failure risk increases
Solution Approach 1:
The system pre-configures multiple relay terminals and their associated parameters before communication begins. When a link failure occurs, the transmitting terminal can immediately switch to a pre-configured alternative relay terminal without requiring time-consuming search and selection procedures, thus maintaining communication reliability while extending coverage area.
2Reliability
If relay terminal switching is implemented for failure recovery, then communication continuity is improved, but system complexity increases
Solution Approach 1:
Multiple relay terminals and their parameters are pre-configured in advance. When link failure is detected through HARQ-ACK reception failures, the transmitting terminal can immediately switch to an alternative relay terminal using the pre-configured information, avoiding complex real-time search and selection procedures.
Solution Approach 2:
The system implements feedback mechanisms where the transmitting terminal monitors HARQ-ACK reception status and reports link quality to relay terminals. This feedback enables automatic detection of link failures and triggers the relay switching process, reducing the need for complex manual intervention while maintaining communication continuity.
3Reliability
If HARQ-ACK threshold-based RLF declaration is used, then false failures are reduced, but detection time increases
Solution Approach 1:
The system changes the parameter for failure declaration from a fixed count to a configurable threshold value. The base station can adjust the HARQ-ACK reception failure threshold according to channel conditions and service requirements, allowing flexible trade-off between detection accuracy and detection time without requiring complex algorithms.
Data Source
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AI summary
Disclosed are a method and a device for link recovery in a sidelink relay communication. An operating method of a transmission terminal comprises the steps of: performing a first SL relay communication with a reception terminal through a first relay terminal; when a preconfigured condition is satisfied, declaring an RLF for a sidelink in which the first SL relay communication is performed; establishing a connection with a second relay terminal; and performing a second SL relay communication with the reception terminal through the second relay terminal.