Research On Spectrum Aggregation Scheme In Cognitive And Cooperative Networks

Because of the limited spectrum resources in cognitive radio network,and the unavailable discontinuous spectrum caused by the fixed allocation of radio spectrum resources,lead to the low utilization and increasingly shortage of spectrum resources.Besides,the development of mobile communication technology have caused a huge number of users in the network,so how to use the existing available spectrum resources to meet the needs of users to transfer heavy traffic in high speed,becoming one of the most popular research points.At the same time,due to the large distance between users or the shadow effect in mobile communication system,the direct transmission usually can take a high price to guarantee the QoS.But if taking use of the multi-relay collaborative technologies,it can reduce the communication distance between the user's and bring diversity gain,thus greatly improving the efficiency and quality of the transmission,so the cooperative relay technology has been widely used.Therefore,in terms of the shortage of the wireless spectrum resource,we conduct the research of the spectrum aggregation scheme in the cognitive cooperative relay networks,to improve the spectrum utilization and network throughput.The main contents of this paper include two aspects:one is the spectrum prediction of cognitive collaborative network,and the other one is spectrum aggregation scheme in multi-user cooperative relay network based the spectrum prediction scheme is proposed above.Through research and found that most of the research combined relay technology and spectrum aggregation technology are mostly focused on the communication scene between single-user,and rarely take the performance of the entire network into account.Thus,in scene of this paper,there are multiple users and they have transmission need simultaneously,and can transfer data by multi-relay.In this network,completing a communication requires at least two slots.Because of the time-varying characteristics of spectrum states,a spectrum prediction scheme has been proposed to reduce the network outage probability.On the basis of the spectrum prediction scheme,and in order to improve the throughput of the network,this paper proposes a spectrum aggregation scheme in multi-user cooperative relay networks,including multi-user relay selection algorithm and spectrum allocation algorithm.Simulation results show that the proposed algorithm can indeed make the maximum throughput of the network,and also can improve the user's channel capacity.