Energy efficient cooperative spectrum sensing in wireless multi-antenna sensor network

This paper will address sensor selection problem for spectrum sensing in a cognitive radio network. The sensor’s limited energy is an important issue which has attracted more attention in recent years. An energy efficient cooperative spectrum sensing will hereby be proposed when multi-antenna sensors are used. Two decision-making techniques are utilized for the combination of antennas’ signals in each sensor: hard and soft decision-making. OR rule is used for hard decision-making technique while selection combining, equal gain combining and maximum ratio combining (MRC) are used for the soft one. In each combination scheme, the sensor selection is a problem by means of which both the energy consumption is minimized and the detection performance gets satisfied. The problem is solved based on the standard convex optimization method. Simulation results show the achievement of a significant energy saving compared to the networks using single-antenna sensors specifically in low signal to noise ratio state. Among all methods, MRC combining enjoys the least energy consumption, as well; it satisfies the desired detection performance.