UE-to-UE Channel Occupancy Sharing via Contention Slots
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Solution Overview
Problem
Existing wireless communication systems face challenges in efficiently utilizing unlicensed spectrum due to the need for listen-before-talk procedures, which introduce delays and inefficiencies in channel occupancy times, especially in sidelink communications between user equipment (UEs), leading to suboptimal performance for latency-sensitive applications.
Innovation Solution
UEs determine contention slot starting times based on listen-before-talk and automatic gain control durations to share channel occupancy times, allowing for efficient sidelink communications by enabling multiple UEs to transmit during a shared channel occupancy time, thereby optimizing resource usage and reducing transmission delays.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If listen-before-talk procedure is implemented in unlicensed spectrum, then channel access reliability is improved, but transmission delay increases
Solution Approach 1:
The channel occupancy time is segmented into multiple contention slots, allowing UEs to perform LBT procedures at specific intervals rather than continuously. This segmentation enables multiple UEs to share the channel efficiently while reducing overall access delay compared to traditional single-occupancy approaches.
Solution Approach 2:
UEs perform LBT procedures in advance at the beginning of each contention slot before actual data transmission. This preliminary action ensures channel access reliability is established beforehand, allowing subsequent transmissions to proceed without additional delays.
2Ease of operation
If single UE occupies channel in unlicensed spectrum, then channel access simplicity is improved, but spectral efficiency deteriorates
Solution Approach 1:
The channel occupancy time is divided into multiple contention slots that can be allocated to different UEs. This segmentation allows multiple UEs to access the channel systematically while maintaining the simplicity of structured channel access procedures.
Solution Approach 2:
The system dynamically allocates contention slots to different UEs based on their transmission needs. This dynamic allocation enables spectral efficiency improvement by allowing multiple UEs to share the channel over time while maintaining manageable access complexity through standardized slot structures.
3Reliability
If LBT duration is extended for reliable channel sensing, then channel access reliability is improved, but channel occupancy time is reduced
Solution Approach 1:
The channel occupancy time is segmented into multiple contention slots, allowing the system to distribute the total LBT duration across multiple shorter sensing intervals rather than requiring one extended sensing period. This segmentation preserves reliability while maximizing usable transmission time.
Solution Approach 2:
By structuring channel access into repeated contention slots with standardized LBT procedures, the system ensures continuous useful transmission action across multiple UEs. The standardized slot structure minimizes idle time between sensing and transmission, maintaining channel occupancy efficiency.
Data Source
AI summary
Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a first user equipment (UE) may determine, within a channel occupancy time shared with a second UE, one or more contention slot starting times based at least in part on a listen before talk duration and an automatic gain control duration. The first UE may transmit a sidelink communication to the second UE at a starting time selected from one or more of the one or more contention slot starting times. Numerous other aspects are provided.