AAF: Data communications in emergency situations through Cognitive Radio

Data communications requires a significant amount of radio spectrum, while spectrum is scarce. Today’s approach divides the spectrum into small pieces, each for a specific purpose. The applications use their spectrum to a limited extent. This leads to the unwanted situation of under-utilization of this scarce public resource. Regulatory bodies (e.g. FCC) recognise the nearly-reached end to this approach, while radio-based communication grows constantly.

Cognitive Radio addresses scarceness in spectrum

The FCC actively pursues Cognitive Radio as a new paradigm in spectrum utilization. A Cognitive Radio utilizes empty spectrum. It searches for under-utilised spectrum, and adapts its transmission without interfering other users. As spectrum use is by definition dynamic, it adapts very rapidly to changes in spectral usage.

Adaptation to spectral utilisation can be in multiple ways. Primary the frequency domain but also the time and space domain are means. Adaptive loading of carriers in combination with adaptive power control can further optimise the communication. Finally interference cancellation and multi-user detection can be added.

Cognitive Radio is a new technology with both issues in technology and legislation. The FCC investigates rule-making aiming at Cognitive Radio. In Europe initiatives in this direction are still very premature.

The AAF project researches how adaptive OFDM with its huge freedom is best applied, considering interference, system stability, capacity and complexity. The project also addresses meta-communications, including neighbour discovery with beacons that fulfil the Cognitive Radio rules, and the communication of transmission parameters.

Download here the complete projectinformation