Energy Efficient Cognitive Radio System for Joint Spectrum Sensing and Data Transmission

An energy-efficient cognitive radio system design is suggested that simultaneously meets spectrum sensing reliability and secondary data transmission rate constraints. System model involves co-located multiple amplify-and-forward relays in single cognitive radio source-destination (S-D) environment with a primary focus on optimal relay power allocation strategy. The problem is mathematically formulated as minimization of total energy consumption under the constraints of sensing reliability (in terms of detection and false alarm probabilities), secondary user throughput and interference threshold to primary user. Then a cluster based nonequal relay power allocation is also suggested. Extensive simulation results illustrate the variation of the minimum energy consumption with the key system parameters.