D2D Synchronization Mode Switching for Coverage Loss
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Solution Overview
Problem
Current wireless communication systems face challenges in providing reliable D2D communications, especially for public safety officials who need harmonized radio access technology across jurisdictions and cost-effective solutions, particularly in areas with limited or no network coverage, such as tunnels, basements, or during natural disasters.
Innovation Solution
The implementation of a method within wireless transmit/receive units (WTRUs) that dynamically determine and adjust their communication mode based on coverage conditions, using pre-configured resources and synchronization signals to facilitate device-to-device (D2D) communications, allowing for seamless transitions between in-coverage, edge-of-coverage, and out-of-coverage scenarios, and enabling resource allocation and synchronization even outside traditional network coverage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If D2D communications are implemented in areas with limited or no network coverage, then reachability and mobility are improved, but synchronization reliability deteriorates
Solution Approach 1:
The system pre-configures synchronization parameters and resource allocation information before the WTRU enters out-of-coverage areas. This preliminary configuration enables the WTRU to maintain D2D communications without real-time network assistance, thereby preserving reachability while ensuring synchronization reliability through pre-established parameters.
Solution Approach 2:
The patent introduces synchronization references and pre-configured resource allocation information as intermediaries between the network and out-of-coverage WTRUs. These intermediaries carry essential synchronization data that enable reliable D2D communications in areas where direct network connection is unavailable, thus resolving the contradiction between reachability and synchronization reliability.
2Ease of manufacture
If D2D communications are used in out-of-coverage areas, then network infrastructure cost is reduced, but communication reliability deteriorates
Solution Approach 1:
The system enables WTRUs to autonomously select resources and maintain synchronization using pre-configured parameters when out of network coverage. This self-service capability allows D2D communications to operate independently of network infrastructure, reducing deployment costs while maintaining communication reliability through autonomous resource management and synchronization maintenance.
3Speed
If pre-configured resources are used for D2D communications, then resource allocation speed is improved, but resource utilization efficiency deteriorates
Solution Approach 1:
The system dynamically adapts resource allocation based on coverage conditions. In out-of-coverage scenarios, pre-configured resources are activated for immediate use, ensuring fast resource allocation. When network coverage is available, the system transitions to network-controlled resource allocation for optimal utilization efficiency. This dynamic switching resolves the contradiction between allocation speed and utilization efficiency.
Solution Approach 2:
The patent changes resource allocation parameters based on coverage state. Pre-configured resource parameters are applied when out of coverage to enable immediate communication, while network-controlled parameters are used when in coverage to optimize resource utilization. This parameter switching mechanism resolves the trade-off between allocation speed and resource efficiency.
Data Source
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Figure 1C
AI summary
A wireless transmit receive unit (WTRU) may be operated in a first scheduling mode for device-to-device communication. In the first scheduling mode, a network entity may schedule resources to be used by the WTRU for device-to-device communications. The WTRU may detect that a radio link failure (RLF) timer is running or has been started. The WTRU may switch from the first scheduling mode for device-to-device communication to a second scheduling mode for device-to-device communication in response to detecting that the radio link failure timer is running or has been started. In the second scheduling mode, the WTRU may select a resource from a resource pool for the WTRU to use for one or more device-to-device communications.