Distributed Spectrum Sensing for Cognitive Radios

Recent studies on spectrum sensing for cognitive radio (CR) reveal that sensing based on single CR may not provide reliable information due to the fact that signals degrade as a result of fading and shadowing. Hence, spectrum sensing based on multiple CR has been considered. In this paper we investigate a distributed sensing based on multiple spectrum sensors where the sensors are located outside the CR. Depending on the channel conditions between sensors (sensor- to-sensor channel) and between the sensor and the radio (user-channel), we explore three different modes of sensing where sensors provide the sensing information either cooperatively or independently. Computer simulation results are provided to validate the concepts.