NR-V2X Terminal HARQ Timing Coordination for Sidelink Responses
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Solution Overview
Problem
In direct terminal-to-terminal communication in NR-V2X, the base station may not know the synchronization timing of the sidelink, leading to a difference in understanding the timing of the PUCCH for transmitting the sidelink HARQ response between the base station and the terminal.
Innovation Solution
A terminal adjusts the timing of transmitting the HARQ response over the uplink by determining the position of the second channel based on a first offset received from the base station and a second offset applied to the first channel, ensuring synchronized transmission with the base station.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the base station does not know the synchronization timing of the sidelink, then D2D communication can operate independently without base station synchronization, but timing alignment between base station and terminal for PUCCH transmission cannot be ensured
Solution Approach 1:
The base station preliminarily determines the timing relationship between sidelink and uplink channels and informs the terminal in advance through offset parameters (firstOffsetIndex and secondOffsetIndex). This allows the terminal to pre-calculate the PUCCH transmission timing before actual transmission, ensuring timing alignment without requiring the base station to know the exact sidelink synchronization timing.
Solution Approach 2:
Offset parameters act as intermediaries between the sidelink channel timing and uplink channel timing. The first offset represents the timing relationship between sidelink and uplink, while the second offset adjusts for base station processing time. These intermediary parameters enable timing coordination without direct synchronization knowledge.
2Productivity
If the terminal transmits HARQ response at determined timing, then communication efficiency is improved, but timing mismatch may occur between base station expectation and actual transmission
Solution Approach 1:
The base station provides feedback in the form of offset parameters that guide the terminal's timing determination. The terminal uses these feedback parameters (firstOffsetIndex, secondOffsetIndex) to calculate the precise PUCCH transmission timing, ensuring that the transmitted HARQ response aligns with the base station's expected reception timing, thus maintaining both efficiency and reliability.
Data Source
AI summary
A terminal includes a receiver configured to receive a response related to retransmission control from another terminal, via a first channel used for transmitting and receiving the response related to retransmission control; a controller configured to receive, from a base station, information representing a first offset in time domain from the first channel to a second channel, the second channel being used for transmitting the received response related to retransmission control to the base station; and a transmitter configured to transmit the received response related to retransmission control to the base station, via the second channel, wherein the controller determines a position of the second channel in time domain based on: the first offset; and a second offset that is applied to a position of the first channel in time domain, and that is used to determine a starting point of the first offset.