Research On Fast Spectrum Sensing And Spectrum Allocation Technology In Cognitive Radio

With the rapid development of communication technology,people's demands for radio spectrum resources are becoming increasingly strong.In order to improve the spectrum utilization,cognitive radio technology appears.This technology refers to the methods that the cognitive users can dynamically sense the idle spectrum and select the access spectrum to communicate without interfering with the primary users.Spectrum sensing and allocation are two important research contents of cognitive radio technology.Based on the model and algorithm of spectrum sensing and spectrum allocation,this paper studies the relay cooperative sensing technology,graph coloring spectrum allocation model of cognitive network respectively,then the corresponding optimization and improvement of these two methods are made.For the research of cooperative spectrum sensing in cognitive networks,this paper first analyzes the cognitive network model which aims at enabling the system obtain a large detection probability and possessing low energy consumption,and then designs a multi-hop relay collaboration algorithm.In the algorithm,the cognitive users first pick out the optimal relay,and then perform the multi-hop cooperative sensing according to the optimal relay.Compared with the original relay cooperative algorithm,the algorithm has better system detection probability and reduces the energy consumption of the relay node in the cognitive network.For the spectrum allocation technology of cognitive radio networks,the research is divided into two parts: Firstly,because the single channel multiuser problem of the CRN system can be regarded as N cognitive users competing for M orthogonal sub-channels problem,this paper uses graph coloring theory to model the system.In addition,in order to solve the problem of fairness of cognitive user access,the target evaluation function of the model is improved.Secondly,considering that spectrum allocation belongs to the non-linear discrete multi-objective problem,and the particle swarm optimization algorithm is suitable for solving the problem,so the binary particle swarm optimization algorithm and the adaptive particle swarm optimization algorithm are combined to solve the improved spectrum allocation model.The improved spectrum allocation algorithm increases the fairness of the user access,and ensures the maximum network benefit and the maximum proportion fairness.