Sidelink Control Information for HARQ Feedback in Groupcast
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Solution Overview
Problem
In sidelink groupcast communication, the lack of hybrid automatic repeat request (HARQ) feedback leads to increased bit error and block error rates due to poor channel states, resulting in degraded transmission performance.
Innovation Solution
Implementing a method for generating and transmitting sidelink control information (SCI) that includes resource allocation for HARQ responses, using orthogonal time-frequency resources and orthogonal cover codes, to enable efficient HARQ feedback and retransmission in sidelink groupcast communication.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If HARQ feedback is implemented in sidelink groupcast communication, then transmission reliability is improved, but device complexity increases
Solution Approach 1:
The resource allocation information is segmented into two distinct parts: first resource allocation information for sidelink groupcast data and second resource allocation information for HARQ response. This segmentation allows the system to implement HARQ feedback functionality while keeping the control information structure organized and manageable, reducing the complexity burden of adding HARQ to groupcast communication.
Solution Approach 2:
The patent introduces a new dimension to sidelink groupcast communication by adding HARQ feedback mechanism. By incorporating feedback channels and procedures in addition to the existing downlink communication structure, the system achieves improved reliability without completely redesigning the existing communication framework.
2Reliability
If orthogonal time-frequency resources are allocated for HARQ responses, then transmission reliability is improved, but resource overhead increases
Solution Approach 1:
The resource allocation is segmented into data resources and feedback resources, with the second resource allocation information specifically designating orthogonal time-frequency resources for HARQ responses. This segmentation ensures reliable feedback transmission while allowing efficient resource management by clearly separating data and control plane resources.
Solution Approach 2:
Orthogonal time-frequency resources are allocated specifically for HARQ response transmission, providing localized high-quality resources for feedback while leaving other resources available for data transmission. This local quality enhancement ensures reliable feedback without requiring all resources to be optimized for feedback purposes.
3Productivity
If SCI includes both data resource allocation and HARQ response resource allocation, then communication efficiency is improved, but information overhead increases
Solution Approach 1:
The patent merges the data resource allocation information and HARQ response resource allocation information into a single SCI message. This combining approach improves communication efficiency by transmitting both types of allocation information together in one control message, reducing the number of separate signaling exchanges required.
Solution Approach 2:
The SCI structure is designed to serve multiple functions: it carries both the first resource allocation information for sidelink groupcast data and the second resource allocation information for HARQ responses. This multi-functionality reduces overall signaling overhead compared to using separate control messages for each function.
Data Source
AI summary
A sidelink communication method performed by a first user equipment (UE) in a communication system includes steps of: generating sidelink control information (SCI) including first resource allocation information for sidelink groupcast data and second resource allocation information for a hybrid automatic repeat request (HARQ) response for the sidelink groupcast data; transmitting the SCI to a plurality of UEs participating in sidelink communication; transmitting the sidelink groupcast data to the plurality of UEs using resources indicated by the first resource allocation information; and receiving the HARQ response for the sidelink group data from one or more UEs among the plurality of UEs using resources indicated by the second resource allocation information.