Group HARQ Feedback Channel Resource Reduction in 5G Sidelink
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Solution Overview
Problem
Current 5G wireless systems face challenges in achieving highly reliable communications for group-based transmissions in New Radio (NR) sidelink communication, particularly in reducing Physical Sidelink Feedback Channel resource usage and enhancing HARQ performance for vehicle-to-everything (V2X) services.
Innovation Solution
Implementing a group-based Hybrid Automatic Repeat Request (HARQ) procedure that utilizes a shared Negative Acknowledgement (NAK) channel, allowing multiple User Equipment (UEs) to share a single feedback channel for HARQ feedback, and enabling any UE to initiate group-based retransmissions without a centralized scheduler, thereby reducing resource requirements and increasing the robustness of HARQ retransmissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a centralized scheduler is used to coordinate HARQ retransmissions, then retransmission coordination is improved, but device complexity and resource overhead increase
Solution Approach 1:
The patent enables UEs to autonomously initiate and coordinate HARQ retransmissions without requiring a centralized scheduler. Each UE that successfully decodes the original transmission can independently decide to retransmit based on local NAK feedback, eliminating the need for complex centralized coordination while maintaining reliable retransmission delivery.
Solution Approach 2:
The patent extracts the retransmission coordination function from a centralized scheduler and distributes it to individual UEs. By removing the centralized scheduling entity for HARQ retransmissions, the system reduces device complexity and resource overhead while maintaining the essential retransmission coordination capability through distributed UE autonomy.
2Reliability
If individual feedback channels are allocated to each UE, then feedback reliability is improved, but Physical Sidelink Feedback Channel resource usage increases
Solution Approach 1:
The patent merges multiple individual feedback channels into a single shared NAK feedback channel for groupcast communications. Multiple UEs share the same feedback channel resources to send NAK indications, significantly reducing the total quantity of feedback channel resources required while maintaining feedback reliability through the shared channel structure.
3Reliability
If retransmission resources are allocated for each UE, then retransmission reliability is improved, but resource overhead increases
Solution Approach 1:
The patent makes retransmission resources universal by allowing any UE in the group to use the same pool of resources for retransmissions. Instead of dedicating specific retransmission resources to each UE, the system creates a shared resource pool that any decoding UE can utilize, reducing total resource overhead while maintaining retransmission reliability through multiple potential transmitters.
4Productivity
If group-based retransmission is implemented, then resource efficiency is improved, but reception quality may deteriorate due to power distribution
Solution Approach 1:
The patent changes the power parameter by leveraging the combined transmission power of multiple UEs performing simultaneous or coordinated retransmissions. When multiple UEs retransmit the same data, their combined power provides diversity gain and improves reception quality, offsetting the resource efficiency gains while actually enhancing reliability through power combining and diversity effects.
Data Source
AI summary
Facilitating a group hybrid automatic repeat request procedure for sidelink group-case in advanced networks (e.g., 4G, 5G, 6G, and beyond) is provided herein. Operations of a method can comprise determining, by a first device comprising a processor, that first information received via a sidelink control channel is successfully decoded and that second information received via a sidelink shared channel is not successfully decoded. The first information and the second information can be received from a second device. Further, the method can comprise transmitting, by the first device, negative acknowledgement data based on a group hybrid automatic repeat request feedback procedure. The method also can comprise receiving, by the first device, retransmission of the second information via the sidelink shared channel from a group of devices in response to the negative acknowledgement data.