Communication Module

Synchrous voice-over-IP for a single frequency radio network

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The company Jöhl + Köferli AG offers tailored radio-transmission solutions. Supplemented by a control system, a central communication infrastructure for public transport emerges.

The comprehensive and reliable radio coverage of an area is always hampered by topographical and structural barriers. The single frequency radio network technology designed by Jöhl + Köferli AG solves this problem by using many spatially separated base stations, which guarantee full coverage of the concerned areas. The base stations emit information, which is synchronised on the same frequency. Thus, the frequency spectrum is used economically, allowing the use of simple terminal devices.

The voice connection between the control system and the base stations is achieved via voice-over-IP. The GPS-based synchronisation, designed to keep a precision up to microseconds, allows the simultaneous emitting of the signal at all base stations.

Supercomputing Systems AG (SCS) has developed a universal hardware platform, which is used by the control system (TMC) as well as the radio transmission site (BSC). It is based upon a multi core ARM Cortex A9 processor and the Altera FPGA technology.

Moreover, the Linux software and the FPGA firmware have been developed for the Voice-over-IP communication, the FSK modems as well as the call decoder.

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The platform can be used for the integration of a variety of other signal processing tasks.

Jöhl + Köferli AG use the module in a flexible and universal way and expand it according to the different requirement of the public transportation companies. Via a web-based configuration panel, adjustments can be quickly performed.

Conctact person at SCS
Christof Sidler

 

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