Sidelink COT Sharing for Groupcast in Unlicensed Spectrum
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Solution Overview
Problem
The increasing demand for mobile broadband communication and V2X services requires efficient sidelink communication methods to manage channel access and occupancy in wireless networks, particularly in unlicensed spectrum, to address latency and reliability challenges.
Innovation Solution
A method and device for wireless communication that involves receiving sidelink control information for scheduling and performing channel access within a channel occupancy time duration based on cast type, destination ID, and channel access priority class, enabling groupcast or broadcast communications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional channel access methods are used in unlicensed spectrum, then channel access is performed independently by each device, but channel occupancy time is limited and access efficiency deteriorates
Solution Approach 1:
The patent merges channel access operations of multiple devices by allowing a first device to share its acquired COT with a second device. The second device performs channel access within the first device's COT duration, effectively combining their channel access opportunities and extending total occupancy time without requiring additional independent channel access procedures.
2Reliability
If channel access priority class restrictions are enforced, then high-priority transmissions are ensured, but low-priority devices face stricter access limitations
Solution Approach 1:
The patent applies different access conditions to different devices based on their CAPC values. The first device with higher priority (lower CAPC value) maintains full access rights, while the second device with lower priority (higher CAPC value) is restricted to accessing only within the first device's COT. This local differentiation ensures high-priority transmissions are protected while still allowing controlled access for lower-priority devices.
3Productivity
If COT sharing is enabled for groupcast or broadcast, then channel access efficiency is improved, but additional control information and coordination overhead are required
Solution Approach 1:
The first device performs channel access and acquires COT in advance, before the second device needs to transmit. By pre-acquiring the COT and sharing its duration information with the second device, the system eliminates the need for the second device to perform independent channel access procedures, thereby improving overall channel access efficiency while minimizing coordination overhead.
Data Source
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AI summary
Provided are a method for a first device to perform wireless communication and a device for supporting same. The method may comprise the steps of: receiving first sidelink control information (SCI) for scheduling second SCI and a physical sidelink shared channel (PSSCH) from a second device through a physical sidelink control channel (PSCCH); receiving the second SCI, including a source ID, a destination ID, an additional destination ID, information related to cast type, channel occupancy time (COT) sharing information, and a channel access priority class (CAPC) value related to the COT sharing information, from the second device through the PSSCH; and performing a second-type channel access within a COT duration acquired through the COT sharing information, the second-type channel access being performed on the basis that: (i) the cast type is set to group-cast or broadcast, (ii) the destination of the first device is related to the additional destination ID, and (iii) the CAPC value related to transmission by the first device is no greater than the CAPC value related to the COT sharing information.