Selective Groupcast HARQ Feedback via Dynamic PSFCH Allocation
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Solution Overview
Problem
Current wireless communication systems face inefficiencies in groupcast transmission and feedback mechanisms, particularly in sidelink communications, where HARQ feedback for groupcast involves high overhead and reliability issues due to shared resources and interference, especially in 5G NR environments with beamforming requirements.
Innovation Solution
Implementing a method where a UE receives a configuration for a resource pool for PSFCH, determines HARQ feedback based on received groupcast data, and transmits feedback using a dedicated PSFCH resource, allowing for selective beamformed transmission and retransmission to improve reliability and efficiency by adapting to the number of NACKs and QoS priorities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If shared resources are used for HARQ feedback in groupcast, then resource utilization is improved, but feedback reliability deteriorates due to interference
Solution Approach 1:
The patent segments the feedback mechanism by introducing two distinct feedback modes: groupcast feedback using shared PSFCH resources and unicast feedback using dedicated PUCCH resources. This segmentation allows the system to choose the appropriate feedback path based on reliability requirements, resolving the contradiction between resource utilization and feedback reliability.
Solution Approach 2:
The patent introduces an intermediary mechanism where the transmitting UE determines whether to request groupcast or unicast feedback based on the number of NACKs received. This intermediary decision-making process enables dynamic switching between shared and dedicated resources, maintaining both resource efficiency and reliability.
2Reliability
If dedicated PSFCH resources are allocated for each UE, then feedback reliability is improved, but resource overhead increases
Solution Approach 1:
The patent implements a dynamic feedback resource allocation mechanism where the feedback mode (groupcast or unicast) is determined dynamically based on the number of NACKs received. This dynamic approach allows the system to use shared resources when possible and switch to dedicated resources only when necessary, resolving the contradiction between reliability and resource overhead.
Solution Approach 2:
The patent changes the parameter of feedback resource allocation from static dedicated allocation to dynamic allocation based on the number of NACKs. This parameter change enables the system to adapt resource usage to actual needs, reducing overhead while maintaining reliability.
3Productivity
If groupcast feedback is used, then resource efficiency is improved, but feedback overhead increases due to multiple UEs transmitting simultaneously
Solution Approach 1:
The patent applies partial action by implementing unicast feedback only when necessary (when the number of NACKs exceeds a threshold), rather than always using groupcast feedback. This partial use of dedicated resources reduces the overall feedback overhead while maintaining resource efficiency for the majority of cases.
4Productivity
If beamformed selective retransmission is implemented, then retransmission efficiency is improved, but system complexity increases
Solution Approach 1:
The patent implements a feedback-driven retransmission mechanism where the transmitting UE receives HARQ feedback from receiving UEs and selectively retransmits data to specific UEs that sent NACK. This feedback mechanism enables efficient targeted retransmission without requiring complex beamforming coordination, resolving the contradiction between retransmission efficiency and system complexity.
Data Source
AI summary
Apparatuses, methods, and systems are disclosed for determining a feedback resource associated with groupcast data. One method includes receiving a configuration associated with a resource pool for PSFCH. The method includes receiving groupcast data via sidelink and determining HARQ feedback based at least in part on the received groupcast data. The method includes determining a PSFCH resource for the HARQ feedback based at least in part on the resource pool for the PSFCH and transmitting the HARQ feedback using the determined PSFCH resource.