Opportunistic radio access techniques for emergency communications: Preliminary analysis and results

In this work, we aim at considering innovative techniques of spectrum management and radio access for emergency communications. In particular, cognitive and opportunistic radio access and resource management have been tested in emergency scenarios. The breakdown of existing wireless network infrastructures can produce a lot of big spectrum holes, i.e.: large frequency spaces not currently used by any kind of primary users. In such a situation, the emergency communication system, instead of remaining “tied down” together with the partially or totally out-of-service terrestrial network infrastructures, may transmit information wherever and whenever it is possible. Single-Carrier Frequency Division Multiple Access (SC-FDMA) has been considered as basic multiple access protocol thanks to its features of agility in frequency and robustness against nonlinear distortions. A radio resource management protocol which maximizes fairness among users has been considered for the cognitive transmission system. Simulation results evidenced a substantial increase of transmission quality and coverage with respect to conventional radio access strategies that do not exploit cognitive features.