Sidelink CPE Position Selection for Unlicensed Spectrum
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Solution Overview
Problem
Current wireless communication systems, particularly 5G NR, face challenges in efficiently transmitting cyclic prefix extensions (CPE) over unlicensed spectrum on sidelinks, leading to potential collisions and interference due to inconsistent CPE starting positions among user equipment (UEs) during frequency division multiplexing (FDM) transmissions.
Innovation Solution
The method involves determining whether an FDM transmission scheme is used for sidelink transmissions, with UEs selecting a default CPE starting position when FDM is employed and randomly selecting from candidate positions based on priority when FDM is not used, to align CPE start locations and prevent collisions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If UEs randomly select CPE starting positions for SL transmission, then transmission flexibility is improved, but collision probability increases
Solution Approach 1:
The patent applies local quality by differentiating CPE starting position selection based on the transmission mode: for FDM transmissions, UEs use a predefined default starting position to ensure alignment and avoid collisions, while for non-FDM transmissions, UEs randomly select from candidate positions to maximize flexibility. This localized differentiation of selection behavior resolves the contradiction between flexibility and collision avoidance in different transmission contexts.
2Reliability
If UEs use default CPE starting position for FDM transmission, then collision avoidance is improved, but transmission adaptability decreases
Solution Approach 1:
The patent implements dynamics by making the CPE starting position selection adaptive to the transmission mode. The UE dynamically determines whether to use the default starting position (when FDM is detected) or random selection (when FDM is not used), based on the actual transmission requirements. This dynamic adaptation allows the system to maintain collision avoidance where needed while preserving flexibility where appropriate.
3Reliability
If CPE starting positions are aligned for FDM transmission, then simultaneous transmission reliability is improved, but position selection flexibility is reduced
Solution Approach 1:
The patent applies local quality by implementing aligned CPE starting positions specifically for FDM transmissions while allowing random selection for non-FDM transmissions. This localized alignment strategy ensures simultaneous transmission reliability is maintained where needed (in FDM mode) while preserving position selection flexibility in other modes, thereby resolving the contradiction between reliability and ease of operation.
Data Source
AI summary
A UE obtains a channel occupancy time (COT) for a set of resources on a sidelink (SL) in an unlicensed spectrum through a channel access procedure. The UE determines whether a frequency division multiplexing (FDM) transmission scheme is utilized for a SL transmission on the sidelink in the COT. The UE selects a cyclic prefix extension (CPE) starting position prior to an initial symbol containing the SL transmission. The UE selects the default CPE starting position as the CPE starting position when the FDM transmission scheme is utilized. The UE randomly selects the CPE starting position from a subset of a set of all candidate CPE starting positions based on an L1 priority of the SL transmission when the FDM transmission scheme is not utilized. The UE transmits a CPE at the selected CPE starting position and performs the SL transmission after the CPE transmission.