Dual Wireless Bridge Roaming for High-Speed Train Connectivity
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
High-speed movement of vehicles, such as bullet trains, poses challenges in maintaining wireless local area network connectivity due to increased roaming latency and packet loss in wireless client devices.
Innovation Solution
The implementation of a system with two wireless bridge devices (WBDs) and a parallel redundancy protocol (PRP) switch, where the WBDs communicate through a peer link and use 'heartbeat' messages to manage roaming, ensuring data packet duplication and transmission through multiple access points to prevent packet loss, and employing staggered roaming to reduce latency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single wireless bridge device is used for high-speed movement, then device complexity is reduced, but roaming latency increases and packet loss occurs
Solution Approach 1:
The system divides the wireless communication function into multiple independent bridge devices (first wireless bridge device and second wireless bridge device). Each device can independently perform roaming operations, allowing parallel processing of connection establishment and data transmission, thereby reducing overall roaming latency without significantly increasing system complexity
Solution Approach 2:
The patent implements preliminary actions by having bridge devices notify each other about upcoming roaming events and by pre-establishing connections with multiple access points before actual data transmission begins. This allows the system to prepare connection parameters and authentication information in advance, reducing the time required during actual roaming transitions
2Device complexity
If a single wireless bridge device is used, then device complexity is reduced, but packet loss increases
Solution Approach 1:
Each wireless bridge device maintains its own independent connection state and quality metrics with different access points. The system evaluates local connection quality at each bridge device independently, allowing selective switching based on actual local conditions rather than relying on a single centralized decision, thereby reducing packet loss through more responsive and accurate connection management
Solution Approach 2:
The patent implements beforehand cushioning by having multiple wireless bridge devices simultaneously connected to multiple access points, creating redundant communication paths in advance. When one connection fails or degrades, the system can immediately switch to alternative paths without packet loss, as the backup connections are already established and ready to receive traffic
3Ease of operation
If wireless bridge devices coordinate roaming individually, then ease of operation is improved, but roaming latency increases
Solution Approach 1:
The patent merges the autonomous roaming capabilities of multiple bridge devices by implementing a coordination mechanism where devices share roaming status information and connection state through peer links. This combined approach allows individual devices to maintain operational independence while collectively optimizing roaming decisions, achieving both ease of operation and reduced latency through synchronized multi-device management
Data Source
AI summary
An apparatus includes a first wireless bridge device configured to transmit signals to and receive signals from wireless network access points located along a pathway, and a second wireless bridge device configured to transmit signals to and receive signals from the wireless network access points. The first wireless bridge device and the second wireless bridge device are coupled to and communicate with each other. When the first wireless bridge device is wirelessly connected to a first access point and about to initiate a roaming mode to attempt to wirelessly connect to a second access point, the first wireless bridge device notifies the second wireless bridge device of the initiating of the roaming mode and determines whether the second wireless bridge device is in the roaming mode while the apparatus is moving along the pathway.