Research On Heterogeneous Network Access Algorithm Based On Cognitive Radio

The development of science and technology has promoted the transformation of mobile communication.The existing single-standard wireless network communication technology has been unable to meet the needs of the users,and the integration of various wireless access technologies has become a trend in the development of mobile communications.The next generation mobile communication system will be a heterogeneous wireless network that covers a variety of wireless access technologies,the various networks are coordinated and integrated to provide the user with the ubiquitous and optimal service experience.Multi-mode terminals move seamlessly in heterogeneous network environment,and mobile users choose corresponding network to communicate according to their own needs.The appropriate selection of network access is the basis for the implementation of the resource management of heterogeneous wireless networks,the balance of network load and the quality of service.Therefore,the network access problem has become a hot topic in heterogeneous wireless network research.This paper improves the existing heterogeneous wireless network access algorithm.In view of the existing network access algorithms,such as low utilization ratio of spectrum resources,unbalanced network load and high handover frequency.On the basis of cognitive radio,the cognitive spectrum perception and sharing technology is used to combine cognitive spectrum sharing with heterogeneous network access algorithms,and a cognitive model based network access mechanism is established in the cognitive heterogeneous network environment.The algorithm comprehensively considers the communication needs of the end users and the rational distribution of the spectrum resources of the network,and realizes the purpose of rational distribution of the network spectrum resource while guaranteeing the user's QoS requirement.The main work and research results of this paper are as follows:Firstly,in the user terminal,this paper proposes an improved hybrid spectrum auction algorithm based on cognitive radio technology,which takes into account the spectrum usage in the two shared modes of underlay and overlay.Auctioneers set the auction rules that purchasers and suppliers can accept.The algorithm aims at maximizing the volume of available free band transactions on the network and takes the price as the benchmark.It improved the current situation of unbalanced utilization of network spectrum resources and the utilization ratio of spectrum resources in heterogeneous networks.Secondly,on the network side,based on the spectrum auction algorithm,a centralized optimization matching centralized optimization matching,algorithm based on the improved bipartite graphs is proposed.The multi-objective matching problem of network spectrum resource utilization,network benefit and user revenue is transformed into a single-objective optimization matching problem based on the effective utilization of network spectrum resources.According to the utilization ratio of spectrum resources,the weights of the bipartite graph are determined,and the maximum weight is obtained through Hungary algorithm,so that users and the network can achieve complete matching.It alleviates the communication conflict,balances the network load,reduces the user's switching probability in the network,and realizes the rational distribution of the network spectrum resource on the basis of meeting the needs of the user communication.Finally,the duration of the network matching is divided into several decision periods,and the classification of various types of user services is considered,and the selection of network access is judged in different periods.Through the simulation analysis,compared with the traditional bipartite graph network matching algorithm,the scheme solved the contradiction between the limited network resource and the low utilization of the spectrum resource.At the same time,the system performance is improved,the network load is balanced,the switching probability of communication between the users is reduced,and the spectrum resource utilization of the heterogeneous network is improved.On this basis,the paper summarizes and forecasts the plan and puts forward the direction of improvement.