Sidelink Feedback Channel Mapping for Low-Latency URLLC
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Solution Overview
Problem
Conventional sidelink feedback reporting techniques in wireless communications systems face challenges with limited opportunities for transmission and delays, which hinder ultra-reliable low-latency communications (URLLC) due to restricted feedback information transmission and latency issues.
Innovation Solution
The implementation of a sidelink resource pool that allows for multiplexing feedback information with other sidelink transmissions using frequency-division multiplexing (FDM) or code-division multiplexing (CDM), along with a configured mapping between sidelink channels and feedback channels, enables reduced latency and improved reliability by allowing multiple repetitions of feedback information.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional sidelink feedback reporting techniques are used, then feedback information can be transmitted, but the number of transmission opportunities is limited and latency increases
Solution Approach 1:
The feedback channel is segmented into multiple feedback channel sub-slots within a slot, creating multiple transmission opportunities. The sidelink resource pool is divided into multiple sidelink channels mapped to corresponding feedback channels, allowing feedback information to be transmitted in different time segments, thereby reducing latency and improving reliability through multiple attempts.
Solution Approach 2:
Feedback information can be transmitted periodically across multiple feedback channel sub-slots. The system configures periodic feedback opportunities where the same feedback information can be repeated in subsequent sub-slots if not successfully transmitted earlier, ensuring reliable delivery while minimizing latency through structured periodic transmission attempts.
2Reliability
If multiple feedback channels are configured with mapping to sidelink channels, then feedback transmission opportunities increase, but system complexity increases
Solution Approach 1:
The feedback channel structure is designed with universal mapping rules that apply across all sidelink channels. Each sidelink channel has a corresponding feedback channel following a consistent mapping pattern, allowing the system to handle multiple channels with a unified approach rather than requiring separate complex configurations for each channel pair.
Solution Approach 2:
The system configurable parameters such as time gap between sidelink channel transmission and feedback transmission, and the number of feedback channel sub-slots, allowing dynamic adjustment of the feedback mechanism to balance reliability requirements against system complexity based on specific deployment scenarios.
Data Source
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AI summary
Methods, systems, and devices for wireless communications are described. A first wireless device may receive control signaling indicating multiple sidelink channels of a sidelink resource pool, a mapping between each sidelink channel of the multiple sidelink channels to a corresponding feedback channel of multiple feedback channels, and a time gap between sidelink channel transmission and feedback transmission with respect to a feedback channel sub-slot of multiple feedback channel sub-slots within a slot. Accordingly, the first wireless device may receive a sidelink data message on a first sidelink channel of the multiple sidelink channels and may transmit sidelink feedback information for the sidelink data message in the feedback channel sub-slot of the slot on a first feedback channel of the multiple feedback channels corresponding to the first sidelink channel. The described techniques may enable the first wireless device to transmit the sidelink feedback information with reduced latency and improved reliability.