Sidelink Process Indication via Sliding Window for HARQ Feedback
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Solution Overview
Problem
Current wireless communication systems face challenges in efficiently indicating sidelink processes for hybrid automatic repeat request (HARQ) feedback due to limited bit capacity in sidelink control information (SCI) and physical sidelink feedback channels (PSFCH), leading to delayed communications and increased processing resources.
Innovation Solution
The method involves indicating a starting sidelink process of a sliding window of sidelink processes within the SCI, allowing for the transmission of HARQ responses on the PSFCH, which reduces the bit usage and conserves signaling resources by coordinating between user equipment (UEs) to select a set of sidelink processes for feedback, thereby optimizing the bit capacity and improving communication efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If all sidelink process indicators are transmitted in SCI, then complete HARQ feedback coverage is achieved, but bit capacity of SCI and PSFCH is exceeded
Solution Approach 1:
The patent segments the set of sidelink processes into multiple sliding windows, where each window contains a subset of processes for which HARQ feedback is indicated. Instead of indicating all processes in one SCI message, the system divides them into manageable segments (windows), with each SCI message handling one window. This segmentation allows complete coverage across multiple messages while keeping individual message bit counts within capacity limits.
Solution Approach 2:
The patent introduces a time dimension by using multiple sliding windows across different time instances. Rather than attempting to fit all process indicators into a single SCI message (one-dimensional constraint), the system distributes indicators across multiple messages in sequence, effectively adding a temporal dimension to the indication process. This allows the system to overcome the bit capacity limitation of individual SCI messages.
2Productivity
If bit capacity of PSFCH is increased to indicate more sidelink processes, then signaling resource consumption increases, but communication efficiency improves
Solution Approach 1:
The patent applies partial action by indicating only a subset of sidelink processes (those within the current sliding window) in each SCI message, rather than indicating all processes simultaneously. This partial indication approach allows the system to maintain efficient communication by processing feedback in manageable batches, reducing the signaling resource burden on each individual PSFCH while achieving complete coverage through multiple sequential messages.
3Quantity of substance
If sliding window approach is used to reduce bit usage, then indication complexity increases, but resource conservation improves
Solution Approach 1:
The patent implements preliminary action by pre-defining sliding window structures and their associated bit representations before actual HARQ feedback transmission. The window sizes, boundaries, and encoding schemes are established in advance, allowing UEs to efficiently encode and decode process indicators without complex real-time calculations. This preliminary setup reduces the operational complexity during actual feedback transmission while maintaining compact bit usage.
Data Source
AI summary
This disclosure provides systems, methods and apparatuses for indicating sidelink processes for sidelink feedback. A second user equipment (UE) may request hybrid automatic repeat request (HARQ) responses from a first UE for a particular set of sidelink processes over a physical sidelink feedback channel. To indicate multiple sidelink processes, the second UE may indicate, in sidelink control information, a window of sidelink processes. The window may be a sliding window that starts with a starting sidelink process and extends through other sidelink processes. The second UE may transmit data for the sidelink processes in the sliding window and receive feedback for the indicated sidelink processes. In some aspects, the first UE may select, in coordination with the second UE, the sidelink processes for which feedback is to be provided.