On the Energy Consumption of the Decision-Fusion Rules in Cognitive Radio Networks

Cognitive radio has been proved to be an efficient solution for spectrum shortage and underutilization problems. However, energy consumption during spectrum sensing is a significant drawback of cognitive radio especially in energy-limited systems. An important stage in spectrum sensing playing a role in increasing the energy consumption is the decision fusion at the fusion center. Many decision-fusion rules have been proposed such as Likelihood Ratio rule (LR), Maximum Ratio Combining rule (MRC) and Equal Gain Combining rule (EGC). A comparison among these rules is presented in this paper. The comparison is in terms of the consumed energy and the achievable detection probability at a given false alarm probability threshold, under a limited time assumption. Simulation results show that in critical conditions, such as short sensing time, low SNR, and large number of users, EGC has a better performance in both energy saving and detection probability.