Cooperative Secondary Users selection in Cognitive Radio Ad Hoc Networks

Secondary Users (SUs) have capability to sense available licensed spectrum in Cognitive Radio Networks (CRNs). Hence, SUs can opportunistically access to the licensed spectrum without disturbing Primary Users (PUs). In this paper, a novel network architecture is proposed to reduce the production cost and the energy consumption for CRNs. The proposed network architecture is based on the spectral requirement of Secondary Users (SUs). In the proposed network architecture, only parts of SUs are equipped with Cognitive Radio (CR) module. In addition, a minimum number of SUs are selected to sense available licensed spectrum, which aims at reducing the energy consumption further. The minimum number of SUs selection problem is formulated as a non-linear programming problem under the constrains of energy efficiency and the real-time available spectrum information. However, the non-linear programming problem is a NP-hard problem. Hence, a distributed heuristic algorithm is proposed to calculate the near-optimal solution. The simulation results demonstrate that the proposed heuristic algorithm in the proposed network architecture outperforms the random algorithm in the proposed network architecture and traditional Cognitive Radio Ad Hoc Networks (CRAHNs) in energy efficiency.