NTN V2X Timing Synchronization via Uplink Reference
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Solution Overview
Problem
Current V2X systems face challenges in timing synchronization due to significant differences in Timing Advance (TA) among UEs, leading to large scheduling delays and potential interference with cellular links when using conventional methods for sidelink transmissions in Non-Terrestrial Networks (NTN) environments.
Innovation Solution
A method where a first node receives signaling indicating a duration set and time window, and transmits a signal based on uplink timing, converting TA into an index to inform V2X receivers about the position of sidelink synchronization signals, allowing flexible resource configuration and precise determination of transmission delays.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional PSCCH transmission according to DL timing and PSSCH transmission according to UL timing is used in NTN V2X, then timing synchronization can be maintained, but large scheduling delay is required to ensure PSSCH does not come before PSCCH due to TA differences
Solution Approach 1:
The patent changes the timing reference parameter from DL timing to UL timing for PSCCH transmission. By using UL timing as the reference and applying TA compensation, the system eliminates the need for large scheduling delays while maintaining timing synchronization. The PSCCH and PSSCH transmissions are both referenced to UL timing, with PSCCH transmitted at time n and PSSCH at time n+k, where k is determined by resource allocation rather than TA compensation requirements.
Solution Approach 2:
The patent inverts the conventional approach by using UL timing instead of DL timing as the reference for PSCCH transmission. Conventionally, PSCCH uses DL timing and PSSCH uses UL timing, creating timing misalignment in NTN. The patent makes both channels use UL timing reference, fundamentally changing the timing relationship and eliminating the scheduling delay problem.
2Reliability
If conventional PSCCH transmission according to DL timing and PSSCH transmission according to UL timing is used in NTN V2X, then timing synchronization can be maintained, but interference with cellular links occurs
Solution Approach 1:
The patent changes the timing reference parameter from DL timing to UL timing for PSCCH transmission. By using UL timing as the reference and applying TA compensation, the system aligns PSCCH and PSSCH transmissions properly, preventing PSSCH from overlapping with uplink reception and thus eliminating interference with cellular links.
3Area of stationary object
If V2X transmissions are configured in NTN with significant TA differences among UEs, then wide coverage is achieved, but large scheduling delay is required to ensure proper timing order
Solution Approach 1:
The patent changes the timing reference from DL timing to UL timing and introduces TA compensation mechanisms. This allows V2X transmissions to proceed with minimal scheduling delay even in NTN environments with significant TA differences among UEs, while maintaining proper timing order between PSCCH and PSSCH.
Solution Approach 2:
The patent applies preliminary TA compensation to the PSCCH transmission timing. By pre-calculating and applying the TA value to determine the transmission time of PSCCH based on UL timing, the system ensures that PSCCH and PSSCH are properly timed without requiring large scheduling delays, enabling efficient V2X communication in wide-coverage NTN scenarios.
Data Source
AI summary
Method and device used in nodes for wireless communications. A first node firstly determines a first duration set, a first time window and a first time length from a base station side, the first duration set belongs to the first time window, and a timing for each duration in the first time window refers to a receiving timing of the first node; it then transmits a first signal in the first target duration according to the timing for the first target duration, the first target duration being deferred by a first time length is a second reference duration, the second reference duration belonging to a first duration set; the first signal indicates a first index. By sending the first index to a sidelink terminal, the present disclosure can prevent interference between a cellular link and a sidelink in a large-transmission-delay system, thus enhancing the system's overall performance.