UE Channel Occupancy Sharing in Shared Spectrum Sidelink Access
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Solution Overview
Problem
Existing sidelink communication systems face challenges in shifting to shared spectrum, leading to potential latency increases due to channel access failures, which hinder low latency and high reliability communications required for applications like NR-V2X.
Innovation Solution
A user equipment (UE) initiates a channel occupancy (CO) and shares it with other UEs, allowing them to perform channel access with higher probability through deterministic sensing durations and priority-based resource allocation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional LBT procedure is used for channel access in shared spectrum, then channel access fairness is maintained, but channel access probability and transmission reliability decrease
Solution Approach 1:
The patent segments the channel access process into two distinct phases: a first LBT procedure performed by the first UE to obtain initial channel occupancy, and a second LBT procedure performed by the second UE within the allocated time window. This segmentation allows each UE to perform simplified channel access checks rather than complex continuous sensing, thereby maintaining reliability while reducing individual device complexity.
Solution Approach 2:
The first UE performs preliminary channel occupancy acquisition through the first LBT procedure before allowing the second UE to transmit. By establishing initial channel access rights in advance, the system enables the second UE to use a simplified second LBT procedure without needing to perform comprehensive channel sensing, thus improving channel access probability while reducing overall procedure complexity.
2Productivity
If channel occupancy time is extended to accommodate more transmissions, then transmission throughput increases, but latency increases due to longer channel occupation
Solution Approach 1:
The patent divides the channel occupancy period into distinct time windows: a first time window for the first UE transmission and a second time window for the second UE transmission. This temporal segmentation allows multiple transmissions to occur within an extended occupancy period while maintaining low latency for each individual transmission, as each UE has a dedicated, predictable time slot rather than sharing the channel continuously.
Solution Approach 2:
The system implements periodic channel access opportunities where the first UE transmits during a first time window and the second UE transmits during a second time window. This periodic structure enables multiple transmissions to be scheduled systematically, improving overall throughput while maintaining low latency through regular, predictable transmission timing rather than continuous or random access.
3Reliability
If priority-based channel access is implemented, then channel access probability for high-priority UEs improves, but fairness between UEs deteriorates
Solution Approach 1:
The patent applies different LBT procedure requirements based on the local conditions of each UE: the first UE must perform the more stringent first LBT procedure to acquire initial channel occupancy, while the second UE, benefiting from the first UE's successful access, can use the simplified second LBT procedure. This local differentiation improves channel access probability for UEs that can leverage shared occupancy while maintaining fairness through the structured opportunity for second UE access within the allocated time window.
Data Source
AI summary
A user equipment (UE) and a method of performing transmission in a shared spectrum by the same are provided. The method includes initiating a channel occupancy (CO) and sharing the CO to at least a second UE. This can solve issues in the prior art and provide a method that the CO initiated by the UE can be shared with other one or more UEs, so that the one or more UEs can have higher probability to access a channel, leading to a low latency communication.