Satellite Communication System for Railway Tunnels
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Solution Overview
Problem
Current satellite communication systems experience discontinuity in railway tunnels due to lack of visibility, with existing solutions being complex, costly, and limited to unidirectional communications or requiring frequency conversions.
Innovation Solution
A satellite communication system comprising a fixed transceiver system with directional and non-directional antennas, and a mobile transceiver system that automatically switches between satellite and ground radio channels using the same carrier frequencies, ensuring bidirectional communication within tunnels by extending satellite signals through optical-fibre connections and electro-optical converters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If satellite communication systems are used in railway tunnels, then communication continuity is improved, but system complexity increases due to need for signal extension infrastructure
Solution Approach 1:
The patent introduces fixed transceiver systems positioned along the tunnel as intermediary devices. These transceivers receive satellite signals externally and retransmit them internally through the tunnel, acting as mediators between the satellite and mobile terminals. This resolves the contradiction by providing communication continuity through intermediate relay points without requiring complex infrastructure throughout the entire tunnel system.
Solution Approach 2:
The tunnel communication system is divided into multiple segments, each served by individual fixed transceiver units. Rather than implementing a single complex system covering the entire tunnel, the patent segments the coverage area and uses multiple simpler transceiver units distributed along the tunnel path. Each segment independently extends satellite signals to its local area, reducing overall system complexity while maintaining continuous coverage.
2Device complexity
If unidirectional satellite signal extension is implemented, then system simplicity is maintained, but communication functionality is limited
Solution Approach 1:
The fixed transceiver units are designed with multi-functionality, serving both downlink (satellite to terminal) and uplink (terminal to satellite) communication functions. Rather than implementing separate unidirectional systems, each transceiver unit handles bidirectional signal transmission, enabling diverse communication services including voice, data, and navigation while maintaining system simplicity through a unified device architecture.
3Reliability
If frequency conversion is used to extend satellite signals, then signal transmission in tunnels is achieved, but system complexity and cost increase
Solution Approach 1:
The fixed transceiver units receive the original satellite signal externally and create a copy of this signal for internal transmission through the tunnel. Rather than converting the signal to different frequencies, the system copies the existing satellite signal and transmits it through the tunnel infrastructure. This approach maintains signal integrity while avoiding the complexity of frequency conversion equipment, achieving reliable signal transmission without additional complexity.
4Reliability
If automatic switching between satellite and ground channels is implemented, then communication reliability is improved, but device complexity increases
Solution Approach 1:
The mobile transceiver system incorporates feedback mechanisms that continuously monitor satellite signal availability and quality. When the train enters or exits a tunnel, the system receives feedback about signal conditions and automatically adjusts its operation by switching between satellite and ground channel modes. This feedback-driven approach improves communication reliability by ensuring continuous connectivity while managing switching complexity through intelligent, condition-based control rather than complex mechanical switching mechanisms.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The system provides seamless, bidirectional satellite communication in tunnels of any length, supporting wide-band services like VoIP, video streaming, and navigation, while optimizing signal reception and reducing environmental impact and energy consumption.
Implementation Method 1
ensuring bidirectional communication within tunnels by extending satellite signals through optical-fibre connections
Implementation Method 2
extending satellite signals through optical-fibre connections and electro-optical converters
Data Source
AI summary
The present invention relates to a satellite communication system for extending communications between a vehicle and a satellite in an area of non-visibility of the satellite. The satellite communication system comprises a fixed transceiver system and a mobile transceiver system. The fixed transceiver system includes a first antenna intended to be positioned outside the area of non-visibility of the satellite, and at least one second antenna coupled with the first antenna and intended to be positioned in the area of non-visibility of the satellite. The fixed transceiver system is configured to receive through the first antenna downlink signals transmitted by the satellite on at least one downlink carrier frequency and to transmit the received downlink signals on the at least one downlink carrier frequency in the area of non-visibility of the satellite through the at least one second antenna. The mobile transceiver system is intended to be installed on the vehicle, includes a third antenna and a fourth antenna, and is configured to receive through the third antenna the downlink signals transmitted by the fixed transceiver system on the at least one downlink carrier frequency, to receive through the fourth antenna the downlink signals transmitted by the satellite on the at least one downlink carrier frequency, to determine whether the vehicle is in the area of non-visibility of the satellite or in an area of visibility of the satellite, and to transmit uplink signals on at least one uplink carrier frequency through the third antenna if the vehicle is in the area of non-visibility of the satellite or through the fourth antenna if the vehicle is in an area of visibility of the satellite. The fixed transceiver system is further configured to receive through the at least one second antenna the uplink signals transmitted by the mobile transceiver system on the at least one uplink carrier frequency and to transmit the received uplink signals to the satellite on the at least one uplink carrier frequency through the first antenna.