Rail Crossing Relay Control for Low-Latency Obstruction Alerts
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Solution Overview
Problem
Existing railroad crossing obstruction detection systems face challenges in reliably transmitting emergency information using public frequency bands like the ISM band, due to radio wave interference and the need for carrier sense, which can lead to delayed notification and inefficient data transfer.
Innovation Solution
A ground system with a relaying function that stores railroad crossing identification information and determines whether to relay notification information using a predetermined wireless communication protocol, allowing for swift and efficient transfer of necessary information to the onboard system without occupying unnecessary bandwidth, even when using public frequency bands.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If wireless communication using public frequency band (ISM band) is used to transfer obstruction information from ground to onboard system, then the system can operate without dedicated frequency band and license costs are reduced, but radio wave interference from other wireless communication systems occurs and transmission reliability deteriorates
Solution Approach 1:
The ground system performs preliminary actions by storing obstruction information and actively searching for the onboard system before actual transmission is needed. This allows the system to be ready for immediate transmission when the onboard system becomes available, reducing waiting time caused by carrier sense requirements.
Solution Approach 2:
The onboard system periodically transmits identification information to the ground system, creating a feedback mechanism. The ground system uses this feedback to identify when the onboard system is available and ready to receive information, enabling reliable communication without dedicated frequency bands.
2Reliability
If carrier sense is performed to search for available communication band before transmission, then transmission can avoid interference with other wireless systems, but waiting time occurs and emergency information transmission is delayed
Solution Approach 1:
The ground system performs preliminary actions by storing obstruction information and actively searching for the onboard system before actual transmission is needed. This allows the system to be ready for immediate transmission when the onboard system becomes available, reducing waiting time caused by carrier sense requirements.
Solution Approach 2:
Instead of the ground system performing carrier sense before transmission, the invention inverts the approach by having the onboard system periodically signal its availability to the ground system. This eliminates the need for ground-based carrier sense and reduces transmission delays.
3Loss of information
If all obstruction information is transmitted from ground to onboard system, then complete information is provided to the driver, but data communication overhead increases and transmission efficiency decreases
Solution Approach 1:
The invention extracts only the essential elements of obstruction information (obstruction type and location) for transmission to the onboard system. The ground system retains complete information including detailed video images, which can be transmitted later or accessed locally. This extraction approach reduces communication overhead while maintaining the ability to provide complete information when needed.
Solution Approach 2:
The information is segmented into different levels: essential information (obstruction type and location) is transmitted immediately to the onboard system, while detailed information (video images) remains at the ground system. This segmentation allows efficient transmission of critical data while preserving access to complete information.
Data Source
AI summary
A railroad crossing obstruction notification system includes a railroad crossing ground system that sends notification information based on detection information on a railroad crossing trouble at a railroad crossing and a relay ground system that is arranged along a track and can relay the notification information. The railroad crossing ground system sends the notification information including an instruction to a train based on the detection information and the railroad crossing ID of the railroad crossing in association with each other. If the railroad crossing ID included in the received notification information matches a relay-required railroad crossing ID of the railroad crossing that is stored as a relay target of the notification information, the relay ground system relays the received notification information.