Research On Spectrum Sensing And Clustering Routing Algorithm In Cognitive Radio Sensor Networks

Cognitive Wireless Sensor Network(CRSN)is a new network combining traditional wireless sensor network(WSN)with cognitive radio(CR)technology.It can effectively alleviate the shortage of spectrum resources in traditional WSN,and has broad prospects for development.However,the application and development of CRSN is subject to malicious attacks and energy constraints.Aiming at the above problems,this thesis proposes two effective solutions.Firstly,a cooperative spectrum sensing optimization strategy for spectrum sensing data falsification(SSDF)attacks is proposed for the malicious attacks faced by CRSN.SSDF attack is one of the major challenges for cooperative spectrum sensing(CSS)in CRSN.In an SSDF attack,a malicious user or many malicious users send false sensing results to the sink node to mislead the global decision about spectrum occupancy.Thus,an SSDF attack degrades the achievable detection accuracy,throughput,and energy efficiency of CRSN.Based on the data delivery evaluation method,two strategies to resist SSDF attack are proposed:(1)a novel attacker-identification strategy,which aims to identify malicious nodes and ignore their sensing results;(2)a novel attacker-punishment strategy,which aims to change the scheduling strategy based on the sensing performance of each node and redistribute transmission opportunities between nodes.The simulation results show that the attacker-identification strategy can effectively identify the malicious nodes and improve the sensing performance.Meanwhile,the attacker-punishment strategy can increase the individual energy efficiency of the normal node and reduce the individual energy efficiency of the malicious node.Secondly,based on the shortages of existing CRSN,a new type of CRSN,named as Heterogeneous nodes CRSN(H-CRSN),is proposed.In the H-CRSN,the source sensing function and spectrum sensing function are undertaken by different nodes respectively.Then an energy efficient clustering routing algorithm for H-CRSN(EECH)is proposed,where the cognitive nodes with the maximum number of available channels and the residual energy over certain energy threshold are chosen as cluster heads,sensor nodes and other cognitive nodes choose to join the clusters according to the rule of minimum communication cost.The simulation results show that the proposed clustering algorithm can efficiently operate in the H-CRSN,and significantly prolong the network lifetime.In this thesis,the existing spectrum sensing and clustering routing algorithms are studied deeply in CRSN,and some optimization schemes are proposed which have some theoretical reference value for future CRSN research.