Research On Cognitive Radio Based Network Resource Optimization Theory And Application

In recent years,there are serious contradiction exists between the rapid increasing requests of the wireless spectrum resources and the lower utility ratio of the spectrum resources under the fixed spectrum access schemes.In order to increase the utility ratio of the wireless spectrum resources,the cognitive radio(CR)has been proposed to satisfy the requirements of the spectrum resources.In the CR technology,the users have been divided into primary users(PU)and secondary users(SU).The SU can share the spectrum resources with PUs,via the technologies of spectrum sensing,spectrum access and spectrum management.In this paper,we focus on the application research of the CR technology.According to the existing research,in this paper,we focus on the E-healthcare system and the wireless communication network in the smart grids.In details,we study the secure spectrum sensing algorithm design in the CR based E-healthcare system,the energy efficient spectrum access technology in the neighborhood area networks of the wireless networks in the smart grids.The main contributions of this paper are as follows:1.we present an secure spectrum sensing algorithm in the CR based E-healthcare system.According to the normal single threshold energy detection scheme,a Triple Threshold Energy Detection(TTED)algorithm is proposed to identify the malicious SUs.to stop the primary user emulation attack.In recent yares,the E-healthcare system becomes more powerful,more wireless access ends are needed.Then,the scarcity of the available spectrum resources becomes serious.Thus,in this paper,we introduce the CR into the E-healthcare system,the cognitive radio based E-healthcare system is proposed.In order to identify the malicious SUs,we present a TTED algoritlum.The detection thresholds are increased,and be optimized jointly.to maximize the detection probability and minimize the false alarm probability.Then.based on the proposed TTED,we analyze and maximize the ayerage channcl throughput,based on the condition that the interferences to PUs are under the given thresholds.2.We present an energy-efficient gateway ON-OFF control strategy in Cognitive radio based Neighborhood Area Networks(CR-NAN).According to the increasing of the number of grid ends and the huge volumes of communication data in single point,the spectrum resource limitation problem becomes serious in smart grid,especially in the NAN.Therefore,the cognitive radio is introduced to NAN,and CR-NAN is proposed.In order to balance the tradeoff between the spectrum resource in the CR network and the transmission requirements in SG network,we propose an optimal spectrum access strategy selection scheme,in which the node can selects suitable spectrum access strategy,based on different transmission requirements and the idle probability of the available channels.Then,in order to balance the tradeoff between the coverage requirement and the energy efficiency of the gateway,we present an energy efficient gateway ON-OFF switching scheme in CR-NAN.The sensing time,transmission power and the gateway ON-OFF control scheme are jointly optimized to minimize the system energy cost,while the coverage requirements are satisfied.3.We present an optimal spectrum allocation scheme for microgrid system,and a access strategy in NAN is proposed.In the microgrids,the transmission data in the grid node include two parts:control data and monitoring data,which make the NAN design becomes a challenge work.In the former,it denotes the power demand and the power prices,while in the latter,it means the monitoring data of the renewable energy equipments(RG),which will be used to forecast the output of the RGs.Therefore,we analyze the impacts for the DRM performance in microgrids caused by the imperfect communications.In detail,we analyze the packet loss ratio for the control data transmission caused by channel fading,and the RG's output forecasting accuracy ratio,caused by the limited spectrum resource in NAN.Then,we propose a spectrum allocation scheme,based on a MAC layer structure,to coordinate the transmissions between the control data and monitoring data.A joint multi-variable single objective optimal problem is proposed,to balance the tradeoff between the DRM performance and the communication cost,to minimize the system cost.Above all,in this paper,we study the application research under two typical scenes.We analyze the secure spectrum sensing algorithm under the CR based E-healthcare system,the matching problem between the spectrum resource in CR network and the transmission requirements in SG nodes in both the temporal and spatial domains,the NAN access network design in microgrids under the imperfect communications.Finally,we evaluate the efficiency of the proposed algorithms and schemes,via massive simulation examples.