UWB Ranging Session Scheduling for Asynchronous Access Control
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Solution Overview
Problem
In UWB communication systems, asynchronous access control devices in transit environments cause interference and delays in granting access due to overlapping ranging sessions, leading to user inconvenience and increased operational costs when synchronized with DL-TDoA networks and additional UWB anchors are deployed.
Innovation Solution
A UWB system with a processing circuit that schedules ranging sessions sequentially and dynamically prioritizes access control devices based on the presence of a user device identifier in a ranging management list, without requiring massive DL-TDoA networks or additional UWB anchors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If asynchronous access control devices are deployed in proximity, then coverage area is improved, but interference between devices causes access delays and failures
Solution Approach 1:
The patent implements dynamic ranging session management where the system continuously monitors interference conditions between access control devices and adjusts ranging session parameters in real-time. When interference is detected, the system dynamically modifies session timing, priority levels, or resource allocation to maintain reliable access grants while preserving multi-device coverage capability
Solution Approach 2:
The system employs feedback mechanisms where access control devices monitor ranging session outcomes and interference levels, then use this information to adjust future session scheduling. The feedback loop enables the system to identify problematic device pairs and implement corrective scheduling decisions, improving access reliability without reducing coverage area
2Reliability
If DL-TDoA networks and additional UWB anchors are deployed to synchronize access control devices, then access reliability is improved, but system complexity and operational costs increase significantly
Solution Approach 1:
The patent extracts the synchronization function from the complex DL-TDoA network infrastructure and implements it through simplified inter-device timing protocols between access control devices themselves. This removes the dependency on extensive anchor networks while maintaining the ability to coordinate ranging sessions and prevent interference
Solution Approach 2:
Access control devices perform self-synchronization by monitoring each other's ranging sessions and autonomously adjusting their own session timing and priorities. This self-service approach eliminates the need for centralized DL-TDoA networks and external UWB anchors, reducing system complexity while maintaining access reliability
3Speed
If multiple ranging sessions are conducted simultaneously with multiple access control devices, then access speed is improved, but interference increases causing session failures
Solution Approach 1:
The patent implements periodic ranging session scheduling where devices conduct ranging operations in coordinated time slots rather than continuously or simultaneously. This periodic structure allows multiple devices to maintain fast access响应 while preventing interference through temporal separation, with the period dynamically adjusted based on traffic conditions and device proximity
Data Source
AI summary
An ultra-wideband (UWB) system of a UWB-enabled device dynamically schedules UWB ranging sessions with multiple asynchronous access control devices. The UWB system creates one ranging session for each access control device and schedules each ranging session with equal priority. During each ranging session, the UWB system receives a ranging message from a corresponding access control device, with the ranging message including a ranging management list (RML) that includes identifiers associated with UWB systems that are within an access control range of the corresponding access control device. The UWB system updates the priority of each ranging session based on presence or absence of the corresponding identifier in the RML of the received ranging message. Further, the UWB system schedules the ranging sessions with the updated priority to dynamically prioritize one access control device, thereby enabling an operation between the UWB system and the corresponding access control device.