NR Sidelink Feedback Scheduling in Unlicensed Spectrum
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Solution Overview
Problem
In NR sidelink transmission, particularly in unlicensed spectrum, the inefficiency of PSFCH transmission leads to resource waste due to discontinuous transmission (DTX) when channels are busy, as receiving terminals fail to send feedback, causing unnecessary retransmissions.
Innovation Solution
Implementing multiple PSFCH transmission occasions for each PSSCH to increase the chances of successful feedback transmission, allowing terminals to utilize unlicensed spectrum effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a terminal device camps on a cell with a large reference signal received power (RSRP) difference between SSB and CSI-RS, then the terminal can camp on the cell, but the terminal may camp on a wrong cell due to measurement inaccuracies
Solution Approach 1:
The patent applies preliminary action by performing compensation calculation before cell camping decision. The network side pre-calculates the RSRP difference between SSB and CSI-RS and provides this compensation value to the terminal in advance. The terminal then uses this compensation value to adjust its measurement results before making the cell camping decision, ensuring accurate cell selection even when the initial RSRP difference is large.
Solution Approach 2:
The patent implements feedback by having the network side calculate and provide compensation information based on the actual RSRP difference between SSB and CSI-RS. This compensation information is fed back to the terminal, which then adjusts its measurements accordingly. This closed-loop feedback mechanism ensures that the terminal can accurately measure cell quality despite large power differences between reference signals.
2Measurement precision
If the network side calculates and provides compensation information for RSRP difference, then measurement accuracy is improved, but network signaling overhead and processing complexity increase
Solution Approach 1:
The patent applies self-service by having the network side automatically calculate the RSRP difference between SSB and CSI-RS based on its own configured parameters. The network side uses its existing knowledge of SSB power configuration and CSI-RS power configuration to compute the compensation value without requiring additional external information or complex inter-node communication, thereby reducing overall system complexity while maintaining measurement accuracy.
3Ease of operation
If the terminal uses SSB RSRP for cell quality measurement, then the terminal can perform measurements, but the measurement is inaccurate when SSB and CSI-RS have large power differences
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the measurement parameter (RSRP value) based on the power difference between SSB and CSI-RS. Instead of using the raw SSB RSRP measurement directly, the terminal modifies the measurement parameter by adding the compensation value that reflects the power difference. This parameter adjustment transforms the inaccurate SSB-based measurement into an accurate cell quality indicator that accounts for the actual service signal power.
Data Source
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AI summary
Embodiments of the present application provide a wireless communication method and a terminal device. One PSSCH corresponds to multiple PSFCH transmission opportunities, thereby increasing transmission opportunities of a PSFCH carrying feedback information corresponding to a PSSCH, so that the terminal device can use an unlicensed spectrum to perform sidelink transmission, thereby optimizing NRSL transmission. The wireless communication method comprises: a terminal device determining a number M of PSFCH transmission opportunities corresponding to a first PSSCH, different PSFCH transmission opportunities of the M PSFCH transmission opportunities corresponding to different time domain resources; for an m-th PSFCH transmission opportunity of the M PSFCH transmission opportunities, the terminal device, according to a result of a channel access procedure, determining whether to use the m-th PSFCH transmission opportunity to transmit a PSFCH carrying feedback information corresponding to the first PSSCH, M and m being positive integers, M ≥ 2, and 1 ≤ m ≤ M.