Software Defined Radio

There are many definitions of Software Defined Radio proposed by research organisations, industry associations, standardization bodies and government entities. The common parameter to the various interpretations is the capability to change the radio waveform through changing software (SW) and without modifying the hardware (HW) and operating environment. This capability can be provided at different levels: the ideal SDR would be able to communicate at any desirable frequency, bandwidth, modulation and data rate by simply loading the appropriate SW. In a more realistic SDR development, this capability would be limited to changes of the modulation, or a limited set of spectrum bands in a contiguous frequency range.

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The evolution of wireless communications towards SDR technology has been supported by two main drivers:

The increased signal processing and computing power of enabling technologies like Digital-Analog (DA) and Analog-Digital (AD) converters, Digital Signal Processors (DSPs), Field Programmable Gate Arrays (FPGAs) and General Purpose Processors (GPPs).
The demand for radio communication solutions, which can provide the needed level of interoperability and re-configurability in operational scenarios.

Troops from European countries operate in most cases in multinational formations when deployed in crisis management operations. It is essential that they can use efficient, robust and interoperable communication systems. Tactical communication systems are crucial, for example for calling in support or supplies.

Nowadays all this can be done through combat network radios and tactical field communication systems. But what happens if the equipment and systems used by different nationalities are unable to access or connect to each other?

In the near future this problem can be solved with the help of SDR. These are designed to accommodate several waveforms for multiple applications. In simple terms, SDR provides one radio to fulfil many purposes. This is made possible by downloading the same coalition waveforms into the different host platforms.

Among all the other players, like the European Commission, NATO, WINNF (Wireless INNovation Forum), ETSI (European Telecommunications Standards Institute) and the European Union Member States , the European Defence Agency (EDA) started in 2006 to investigate SDR based technology to enhance interoperability for military purposes. EDA contracted a study called SCORED, addressing Military Software-Defined Radio capabilities including Cognitive Radio-based Spectrum Management in the Security and Defence domains, at the same time as the European Commission led a study on Wireless Interoperability for Security (WINTSEC).

These studies were complementary and formed a basis for SDR related capabilities in Europe for military and civilian users. Both studies lasted around 24 months and the final results were delivered and presented together in a joint event in March 2009, at EDA. The results assist in the EDA Cat "B" project named ESSOR (European Secure SOftware defined Radio).

Likewise, the European Commission has started a complementary study looking at a technology demonstrator for the public safety domain (European software defined radio for wireless in joint security operations – EULER).

European defence SDR efforts are co-ordinated in the EDA Project Team (PT) SDR where the participating Member States can collaborate easily for the development of joint and common capabilities. In the meetings of this PT, updates on activities from other EDA Directorates with impact on SDR activities are usually presented to the pMS, in order to provide them with understanding and visibility. Examples are the operational and technical management of the Radio Spectrum or R&T studies on waveforms for different requirements (high data rates, robustness).