Unlicensed CV2X Resource Selection Using Shared COTs
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Solution Overview
Problem
In unlicensed cellular vehicle-to-everything (CV2X) communications, existing technologies face challenges in efficiently selecting resources for packet transmission due to the need for listen-before-talk (LBT) procedures, which can lead to reduced reliability and increased latency due to persistent interference and blocked transmission slots.
Innovation Solution
A method and apparatus for selecting resources based on channel occupancy time (COT) sharing, allowing transmission without Category 4 LBT in certain conditions, adapting resources based on initiated COT, and optimizing transmission slots within the COT.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If listen-before-talk (LBT) procedures are implemented for channel access, then channel collision is reduced, but transmission reliability decreases and latency increases due to persistent interference and blocked transmission slots
Solution Approach 1:
The patent applies preliminary action by performing resource selection and COT identification before actual packet transmission. The UE identifies upcoming COTs in advance and pre-adapts transmission resources to fall within these COTs, allowing transmissions to occur without LBT procedures. This advance planning eliminates the need for real-time LBT checks during transmission, thereby reducing latency while maintaining reliable channel access.
Solution Approach 2:
The patent uses COT (Channel Occupancy Time) information as an intermediary mechanism. By identifying and utilizing COTs initiated by other UEs or base stations, the system creates a shared channel access window where multiple transmissions can occur without contention. This intermediary COT structure allows UEs to bypass LBT procedures during these windows, improving both reliability and reducing latency compared to traditional LBT-based access.
2Productivity
If LBT procedures are performed before each transmission, then channel access fairness is improved, but productivity decreases due to increased number of LBT procedures required
Solution Approach 1:
The patent merges multiple transmission opportunities into shared COT windows. Instead of performing separate LBT procedures for each transmission, multiple UEs can transmit within a single COT that was established by one UE. This consolidation reduces the total number of LBT procedures required in the system, thereby improving overall productivity and reducing the computational burden on individual devices.
Solution Approach 2:
The system performs preliminary COT identification and resource adaptation before transmission, eliminating the need for repeated LBT procedures. By pre-selecting resources within identified COTs, the system reduces the frequency of LBT executions, simplifying the device complexity while maintaining high transmission productivity through efficient resource utilization.
3Productivity
If resource selection is performed without COT awareness, then resource selection simplicity is maintained, but transmission efficiency decreases due to missed opportunities within shared COTs
Solution Approach 1:
The patent implements preliminary COT identification and resource adaptation, where the UE identifies upcoming COTs and pre-adapts its transmission resources to fall within these COTs. This advance preparation enables the UE to exploit shared channel access opportunities without adding significant complexity to the resource selection process, thereby improving transmission efficiency by capturing otherwise missed transmission opportunities within shared COTs.
Solution Approach 2:
The system uses feedback from COT identification mechanisms to adapt resource selection. By monitoring and identifying COTs initiated by other UEs or base stations, the system gains feedback information about available shared channel access windows. This feedback-driven adaptation allows UEs to efficiently select resources within these windows, improving transmission efficiency while maintaining relatively simple resource selection logic through rule-based adaptation.
Data Source
AI summary
Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a user equipment (UE) may select, from an available resource pool, one or more resources for transmitting a packet on a channel. The UE may determine that a new shared channel occupancy time (COT) has been initiated on the channel. The UE may adapt at least one resource of the one or more resources for transmitting the packet based at least in part on determining that the new shared COT has been initiated. Numerous other aspects are provided.