Uu-Link Retransmission Signaling for Sidelink HARQ Resource Requests
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing communication systems for Vehicle-to-Anything (V2X) and Cellular Intelligent Transportation Systems (C-ITS) face challenges in reliably indicating retransmissions over the Uu-link, as current methods either lack resource indication or incur high latency, especially for latency-sensitive traffic.
Innovation Solution
A device and method for reporting retransmission information (RI), resource request information (RRI), and buffer status information (BSI) over a Uu-link, based on processing HARQ feedback received over sidelinks, using compact signaling and predefined rules to determine and transmit Second-Link Retransmission Indications (SRI) efficiently.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If SL HARQ ACK/NACK is forwarded to gNB over Uu link, then retransmission indication is provided, but resource information for retransmission is not indicated and both ACK and NACK are used inefficiently
Solution Approach 1:
The patent segments the retransmission indication into two separate components: (1) a retransmission indication bit that clearly signals whether retransmission is needed, and (2) a resource indication field that specifies the resources required for retransmission. This segmentation resolves the contradiction by providing both functions through dedicated fields rather than attempting to convey both pieces of information through a single ACK/NACK mechanism.
2Productivity
If SR is sent together with BSR for fast retransmission resource request, then resource request is made, but latency increases significantly for latency-sensitive traffic
Solution Approach 1:
The patent applies preliminary action by pre-configuring multiple SR resources and associated BSR resources before they are needed. When a retransmission is required, the UE can immediately activate a pre-configured SR resource without waiting for BSR processing, thereby reducing latency. The gNB is pre-informed of the buffer status through the SRI, eliminating the need for separate BSR processing delays.
3Quantity of substance
If BSR reporting is used for resource allocation, then buffer status is reported, but clear indication of SL retransmission or resource request is not provided
Solution Approach 1:
The patent merges the buffer status reporting function with the retransmission indication function into a single SRI message. The SRI includes both the buffer status information (indicating available resources for retransmission) and the retransmission indication (clearly signaling that retransmission is required). This merging resolves the contradiction by providing both pieces of information in one unified message rather than requiring separate signaling mechanisms.
Data Source
Figure 1
Figure 2
Figure 3
AI summary
The present invention relates to retransmission processes, e.g. Hybrid Automatic Repeat Request (HARQ) processes. The invention is concerned with providing an indication, over a first link, related to retransmission(s) with respect to a second link. To this end, the invention provides a device configured to communicate over the first link and over at least one second link. The device is further configured to determine, based on at least one communication over the at least one second link, retransmission information (RI), and/or resource request information (RRI), and/or buffer status information (BSI) regarding the at least one second link. The device is then configured to transmit a first message over the first link, wherein the first message includes the RI, and/or the RRI, and/or the BSI.