Nested PSFCH Sub-pools for Sidelink HARQ Collision Avoidance
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current sidelink communication systems face challenges with HARQ collisions due to the limited number of available time-and-frequency resources, leading to inefficiencies in resource allocation and increased probability of collisions, especially when multiple devices share the same 8-bit L1 source ID.
Innovation Solution
The implementation of a method where user equipment (UE) selects a specific physical sidelink feedback channel (PSFCH) resource sub-pool for receiving HARQ feedback by transmitting a PSFCH resource sub-pool indication, allowing for spatial reuse of time-and-frequency resources and minimizing collisions through resource partitioning and virtual L1 source IDs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If spatial reuse of time-and-frequency resources is enabled for SL transmission, then resource allocation efficiency is improved, but HARQ collision probability increases
Solution Approach 1:
The PSFCH resource pool is segmented into multiple sub-pools (first PSFCH resource sub-pool and second PSFCH resource sub-pool) based on the source ID of the SL transmission. This segmentation allows devices with different source IDs to use different sub-pools for HARQ feedback, thereby reducing collision probability while maintaining spatial reuse efficiency.
Solution Approach 2:
Different sub-pools are assigned different qualities or characteristics based on the source ID. The first sub-pool is associated with a first set of source IDs while the second sub-pool is associated with a second set of source IDs. This local differentiation ensures that devices with overlapping source ID ranges use appropriate sub-pools, optimizing both resource efficiency and collision avoidance.
2Device complexity
If a single PSFCH resource pool is used for all SL transmissions, then device complexity is reduced, but HARQ collision probability increases
Solution Approach 1:
The PSFCH resource pool is divided into multiple sub-pools that are selectively used based on the source ID. This segmentation enables the system to maintain manageable complexity by using a hierarchical structure (pool -> sub-pools) rather than a completely flat approach, while significantly improving HARQ feedback reliability through collision avoidance.
Solution Approach 2:
The system dynamically selects which sub-pool to use based on the source ID of the SL transmission. This dynamic selection mechanism allows the system to adapt to different transmission scenarios without requiring complex static configuration, balancing device complexity with improved reliability.
3Reliability
If multiple PSFCH resource sub-pools are implemented, then HARQ collision probability is reduced, but resource allocation complexity increases
Solution Approach 1:
The PSFCH resource sub-pools are pre-configured and pre-assigned to specific source ID ranges before SL transmissions occur. This preliminary configuration eliminates the need for complex real-time negotiation or dynamic resource allocation algorithms, reducing operational complexity while maintaining effective collision avoidance through the pre-established sub-pool structure.
Data Source
AI summary
The apparatus may be a UE configured to select, from a plurality of PSFCH resource sub-pools of a PSFCH resource pool for receiving HARQ feedback, a particular PSFCH resource sub-pool for receiving HARQ feedback associated with a particular SL transmission; transmit, to at least one UE, a PSRI identifying the particular PSFCH resource sub-pool; and receive, from the at least one UE, HARQ feedback regarding the particular SL transmission, the HARQ feedback being received via resources in the PSFCH resource sub-pool indicated by the PSRI. The apparatus may be a base station in a Mode 1 resource allocation that may select, from a plurality of PSFCH resource sub-pools of a PSFCH resource pool for receiving HARQ feedback, a particular PSFCH resource sub-pool for receiving HARQ feedback associated with the particular SL transmission and transmit, to a UE, a PSRI identifying the particular PSFCH resource sub-pool.