Sidelink COT Sharing for Unlicensed Spectrum Access
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Solution Overview
Problem
There is a need for efficient channel access configuration and resource allocation schemes for sidelink communication in unlicensed spectrum, particularly for NR sidelink operation, to support various access priorities and enhance throughput, reduce latency, and offload traffic from licensed spectrum.
Innovation Solution
A wireless communication method and system that includes COT initiating and sharing mechanisms, resource reservation, and HARQ feedback schemes for sidelink communication in unlicensed bands, utilizing channel access priority classes and cyclic prefix extensions to manage channel access and transmission in Mode 1 and Mode 2 resource allocation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If COT sharing mechanism is implemented for sidelink communication in unlicensed spectrum, then throughput is improved and latency is reduced, but device complexity and protocol overhead increase
Solution Approach 1:
The COT sharing mechanism is segmented into distinct phases: COT initiation by one UE, COT sharing information transmission via SCI, and COT utilization by other UEs. This segmentation allows complex channel access procedures to be broken down into manageable steps, improving throughput while controlling complexity through structured protocol design.
Solution Approach 2:
The initiating UE performs preliminary channel access procedures (LBT) and secures the COT before sharing it with other UEs. By performing the complex channel access action in advance, the system enables subsequent UEs to transmit without repeating the full access procedure, thereby improving throughput and reducing latency while the complexity is confined to the initial actor.
2Productivity
If multiple UEs share the same COT for sidelink transmission, then resource utilization is improved, but collision probability and interference management complexity increase
Solution Approach 1:
The COT sharing mechanism incorporates feedback through SCI transmissions that carry COT sharing information. Receiving UEs decode this information to understand the shared COT parameters and their own transmission rights, providing feedback control that coordinates multiple UEs' transmissions within the same COT, thereby improving resource utilization while maintaining collision avoidance through informed transmission decisions.
3Reliability
If channel access priority classes are introduced for different sidelink services, then service differentiation and reliability are improved, but protocol complexity and configuration overhead increase
Solution Approach 1:
Different channel access priority classes (CAPC) are assigned to different sidelink services based on their specific reliability requirements. High-priority services (e.g., safety-critical V2X) use more aggressive channel access parameters while lower-priority services use more conservative parameters. This local quality differentiation improves service reliability without requiring all UEs to implement all possible access schemes, thereby controlling overall system complexity.
Data Source
AI summary
A wireless communication method for execution by a user equipment (UE). The UE receives channel occupancy time (COT) initiating information from a base station and performs COT initiating to initiate a COT based on a channel access scheme. The UE generates COT sharing information and transmitting the COT sharing information in a first SL burst to a second UE. The UE receives from the second UE a second SL burst within the shared COT.