Sidelink HARQ Feedback Mechanism for Adaptive Retransmission
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Solution Overview
Problem
Current wireless communication systems lack a mechanism for actively requesting retransmissions over sidelinks in case of non-successful transmissions, leading to inefficient spectral usage and lack of link adaptation in sidelink communications.
Innovation Solution
Implementing a retransmission protocol for sidelink communications that allows transceivers to perform retransmissions based on explicit or implicit feedback, using Hybrid Automatic Repeat Request (HARQ) protocols and channel quality indicator reporting, enabling adaptive retransmissions only when necessary.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If blind retransmissions are performed without feedback mechanism, then transmission reliability is improved, but spectral efficiency deteriorates due to unwarranted retransmissions
Solution Approach 1:
The patent implements a feedback mechanism where the receiving transceiver sends explicit feedback signals (ACK/NACK) or implicit indicators to the transmitting transceiver. This feedback enables the transmitter to determine whether retransmission is necessary, thereby avoiding unwarranted retransmissions and improving spectral efficiency while maintaining transmission reliability through targeted retransmission when needed.
2Loss of energy
If retransmission protocol with feedback is implemented, then spectral efficiency is improved by reducing unwarranted retransmissions, but device complexity increases
Solution Approach 1:
The patent enables the receiving transceiver to autonomously generate and send feedback signals based on successful or unsuccessful decoding of received data packets. The transmitting transceiver uses this feedback to self-determine whether retransmission is needed, eliminating the need for complex centralized control while improving spectral efficiency through adaptive retransmission decisions made by the devices themselves.
3Adaptability or versatility
If HARQ protocol with explicit feedback is used, then link adaptation is improved, but communication overhead increases
Solution Approach 1:
The patent implements link adaptation using feedback signals that are transmitted only when necessary - specifically, when the receiving transceiver fails to successfully decode a data packet. Instead of continuous feedback, the system uses selective feedback (implicit NACK when decoding fails, or explicit ACK/NACK only when needed), thereby achieving link adaptation while minimizing communication overhead by avoiding unnecessary feedback transmissions.
Data Source
AI summary
A wireless communication system includes a plurality of transceivers. The plurality of transceivers include at least a first transceiver and a second transceiver. The first transceiver and the second transceiver are configured for a sidelink communication with each other. The wireless communication system supports a retransmission protocol for the sidelink. The retransmission protocol enables the first transceiver to perform a retransmission for a data packet, responsive to an explicit or an implicit feedback from the second transceiver, which receives one or more data packets from the first transceiver, in case of a non-successful transmission of the data packet over the sidelink.