Research On Spectrum Sensing And MAC Protocol In Cognitive Radio Sensor Networks

Cognitive Radio Sensor Network(CRSN)is a new type of network combining the traditional wireless sensor networks(WSN)with cognitive radio(CR).It can effectively alleviate the shortage of spectrum resources in traditional WSN,and has a great potential for development.However,CRSN still uses traditional batteries to supply energy,the application and development of CRSN is faced with the problem of resource restrictions and energy constraints.This thesis researchs on these two issues and puts forward an effective solution.Based on the hybrid spectrum sensing method,the third chapter proposes a saving energy node selection algorithm(SENS)which effectively reduces the number of nodes participated in spectrum sensing.The algorithm reduces the loads and energy consumption of the cognitive wireless sensor networks,At the same time,it can also solve the energy consumption problem in the traditional wireless sensor network.This algorithm which considers the perception of energy consumption and performance parameters of nodes(_dP,_fP)forms a node priority function,the network selects the nodes according to the priority of nodes,It reduces energy consumption.Moreover,this thesis uses the"OR"standard,the node whose local sensing decision is“1”transmits the local sensing result to the fusion center.So it can reduce the energy consumption in the process of information transmission and achieve the purpose of energy saving.The simulation results show that SENS algorithm can effectively reduce energy consumption while satisfying the requirements of perceived performance.In order to reduce the energy consumption generated by cognitive process and reduce the cost of functional implementation in CRSN,a new typological network is proposed in the fourth chapter.First of all,the nodes with the cognitive function are classified as one class,and the information processing and energy collection ability of this kind of node has been improved,and then the independent cognitive node and the common sensor node are redeployed in a certain proportion,forming heterogeneous cognitive radio sensor networks(HT-CRSN).In order to improve the network's ability to process information and reduce deployment costs,HT-CRSN focuses most of its processing tasks on cognitive nodes with strong performance.Since the traditional MAC protocol is difficult to apply to this new network,the working time sequence and MAC Protocol for HT-CRSN are proposed in this chapter,and the energy consumption analysis and simulation verification of the protocol are carried out.By adjusting the deployment ratio of CNs and and SNs and the energy collection rate of CNs,the energy consumption of two types of hetenegeneous nodes can be balanced,and the life cyle of the network can be improved from the simulation results.In this thesis,the spectrum sensing in CRSN and MAC protocols are studied in detail,and some optimization schemes are put forward.Last of all,the existing theory in CRSN is extened further.