RFoF Multi-Radio Interconnect System

RFOptic’s RFoF Multi-Radio Interconnect System provides multi-channel private wideband RF connection between multiple radios and data links. This RFoF System is fully bidirectional and implements a  shielded and private equivalent of over-the-air connectivity of numerous radio channels. All radios are able to receive and transmit to all other radios through a fully isolated Optical interconnect without any emissions or susceptibility to external interference. Main applications are: Flight simulator radios cross-communication and group training radio infrastructure.

Key advantages of RFoF instead of coax for multi-simulator radio interconnect systems include:

• RF over Fiber instead of coax allows for substantial distance between the radios which are usually installed in separate buildings and are attached to different flight simulators or similar trainers.
• It is isolated and secure radio interconnection which prevents emissions and external interference.
• The system concept can be adopted to support wideband signals for additional functions including for example sharing RADAR or EW signals.
• It is flexible and scalable supports a customizable number of radio channels per site and number of sites.

Frequency range & RF coverage

The frequency coverage of the system includes HF bands starting at 1MHz while the coverage is typically up to 3GHz, which can be extended to higher frequencies upon request.

Key characteristics

Both enclosures include Tx with built-in LNA and Rx RFoF terminal units. Each of these includes a variable attenuator which can be used to customize the Noise Figure, Input P1dB, and IP3 over wide range of values. For special applications requiring temperature stability operation, a unique optional temperature compensation algorithm supports ±0.5 dB over 100⁰C variation of the ambient temperature. The RFoF link has excellent gain flatness with 0.5dB gain adjustment and tracking between links.

• Integrated and flexible multi-channel bidirectional RF Over Fiber (RFoF) cross-connect system.
• Full support for the 1MHz to 3.0GHz bandwidth.
• Excellent linearity and gain control.
• Programmable RF and Optical performance.
• Built-in end-to-end diagnostics reduce installation and maintenance time.
• Integrated RF and optical power sensors.
• Reduced gain variation over temperature.
• Remote management and control via HTML/REST/SNMP interface.

System configuration

The system is set up in a star configuration where each simulator node which houses its radios is located at one of the vertices of the star. It contains one bidirectional terminal per radio and is connected to a central or control node at the center. The center node includes the counterpart of the bidirectional RFoF link for each radio of a simulator site as well as an RF Fabric interconnect unit which cross-connects all signal ports to all others. The RFoF links are fully configurable and are remotely managed and controlled by RFOptic’s M&C interface allowing optical and RF diagnostics as well as fault detection. This flexibility of configuration and the subsystem’s remote management and control functionality through HTML/REST/SNMP interface allow the system to handle very different application and requirements. Optional power attenuators are added to handle high-power (typically 20W) radios.

• 19” 1U Indoor enclosures.
• Configurable number of channels per site.
• Configurable number of radio sites.
• Other frequency ranges are available.

Conclusion

This system meets the demand for flexible, multi-simulator bidirectional radio interconnect. It simulates over the air transmissions within an RFoF isolated and secure medium. The system supports numerous radio channels of flight simulators and similar trainers and enables group training with cross-communication between all the radios. This system has been tested and is being deployed by the military.