Unlicensed Sidelink COT Sharing via TDM and FDM Sub-Channels
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Solution Overview
Problem
Efficient resource utilization for sidelink communications in shared (unlicensed) channels is challenging due to inefficient allocation of channel occupancy time (COT), which restricts access for other user equipment (UEs) and may lead to interference.
Innovation Solution
Implementing sub-channel-based occupancy time sharing, where a UE transmits a sharing indicator to share a portion of the channel resources, allowing other UEs to access the shared channel without a full contention process, using time-division multiplexing (TDM) or frequency-division multiplexing (FDM) sharing indicators.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a UE performs a full channel access procedure to gain access to the shared channel bandwidth, then the UE can transmit sidelink data messages reliably, but the access latency increases and resource utilization efficiency decreases
Solution Approach 1:
The patent applies preliminary action by having the first UE perform the full channel access procedure and obtain channel occupancy time (COT) in advance, then share this pre-acquired channel access opportunity with the second UE. The sharing indicator message预先 indicates the sharing intent and resources, allowing the second UE to access the channel without performing its own full contention process, thus reducing access latency while maintaining reliability through the first UE's prior channel acquisition
Solution Approach 2:
The patent uses the sharing indicator message as an intermediary mechanism between the first UE and the second UE. This message carries channel access information and resources from the first UE to the second UE, enabling the second UE to utilize the first UE's acquired COT without direct contention. The intermediary facilitates efficient resource transfer while maintaining proper channel access control
2Reliability
If a UE performs a full channel access procedure, then the UE can ensure proper channel control and interference management, but the overall resource utilization efficiency of the shared channel bandwidth decreases
Solution Approach 1:
The patent merges the channel access efforts of multiple UEs by allowing the second UE to utilize the channel occupancy time (COT) acquired by the first UE. Instead of each UE independently performing full channel access procedures, the system combines their access attempts into a single successful acquisition by the first UE, which is then shared with the second UE through the sharing indicator mechanism, thereby improving overall resource utilization efficiency while maintaining proper channel control
Solution Approach 2:
The first UE performs the channel access procedure preliminarily and acquires COT in advance, then shares this pre-acquired resource with the second UE. This preliminary action eliminates the need for the second UE to perform redundant channel access procedures, allowing both UEs to efficiently utilize the shared channel bandwidth while maintaining proper access control through the established sharing mechanism
3Productivity
If a UE shares channel occupancy time with other UEs, then the resource utilization efficiency improves, but the system complexity increases due to additional signaling and coordination requirements
Solution Approach 1:
The sharing indicator message is transmitted preliminarily before the actual data transmission, carrying all necessary channel access information and resource allocation details in advance. This preliminary signaling allows receiving UEs to prepare and execute their transmissions without requiring complex real-time coordination during the actual data phase, thereby improving resource utilization while managing system complexity through advance planning
Solution Approach 2:
The patent changes the parameter of channel access coordination from continuous real-time interaction to discrete event-based signaling. By using the sharing indicator message to convey all necessary parameters (COT duration, frequency resources, time resources) in a single transmission, the system reduces ongoing coordination complexity while enabling efficient resource sharing through clearly defined parameter specifications
Data Source
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AI summary
Methods, systems, and devices for wireless communications are described. In some systems, user equipment (UEs) may communicate over sidelink channels in a shared (e.g., unlicensed) channel bandwidth. A UE may implement sub-channel-based occupancy time sharing for the unlicensed sidelink to improve resource usage. The UE may gain access to the shared channel bandwidth for an occupancy time and may transmit a sharing indicator indicating a portion of resources of the shared channel bandwidth for the occupancy time. The UE may transmit a time-division multiplexing sharing indicator to share a portion of slots of the occupancy time, a frequency-division multiplexing sharing indicator to share a portion of sub-channels of the shared channel bandwidth, or some combination thereof. A UE receiving the sharing indicator may identify the shared resources and may transmit in these shared resources (e.g., without performing a full contention process for an occupancy time).