Research Of Cognitive Radio Ad Hoc Networks Based On Complex Network Theory

In recent years,the rapid development of wireless communication technology has led to increased demand for radio spectrum,and the shortage of spectrum resources is becoming increasingly significant.Cognitive radios(CRs)are considered to be able to effectively solve the scarcity problem of spectrum resources due to their strong cognitive capabilities and reconfiguration capabilities.Dynamic network topology is a key component of cognitive radio ad hoc network(CRAHN)technology.In the networking environment with dynamic spectrum changes,how to construct a fast and robust network becomes a major difficulty.Firstly,this paper investigates the main characteristics,key technologies and challenges of CRs and CRAHNs.The application potential and significance of the topological characteristics and models of complex network theory in CRAHNs are also analysed.On this basis,this paper proposes an energy optimization cognitive ad hoc network algorithm based on link prediction.By introducing interference to primary users(PUs)and mobility of cognitive users(CUs),this algorithm proposes an evaluation criterion for dynamic link reliability.Combining with the energy optimization strategy of CUs,a corresponding CRAHN path optimization method is proposed.This method can improve the robustness of cognitive ad hoc network by optimizing the selection of more reliable links in dynamic network topology.Learning from the analysis method of network characteristics on network topology robustness in complex network theory,this paper simulates and studies the network topology robustness of this algorithm.Simulation results show that the algorithm can effectively reduce re-routing frequency,thereby reduce the system energy consumption,and thus prolong the network life.Based on the aforementioned networking algorithm,this paper extends our research by using network invulnerability as the optimization goal,and proposes a minimum network overhead invulnerability optimization algorithm.The algorithm is based on a multi-tree structure and meets the invulnerability constraints of two-degree connectivity by minimizing the energy cost of networking.Compared with the classical Integer Linear Programming(ILP)model algorithm,the significant superiority of the proposed algorithm in guaranteeing network robustness is proved through system simulations.