Research On Clustering And Routing Algorithms And Trust Enhancement Techniques Of Wireless Sensor Networks

In recent years,the government,scientific research institutions and enterprises have attached great importance to and further study of the Internet of things.Wireless sensor networks as an important part of Internet of things have been widely applied in national defense,military,environmental monitoring,traffic management,health care.A Wireless sensor network consists of hundreds of thousands of low cost,small and battery-powered sensor nodes,which collaboratively collect and process the monitoring information,and send the information by wireless communication mode.Therefore,wireless sensor networks neednot to deploy sophisticated communication cable,and have advantages of low cost,flexible communication.However,the sensor nodes have limited computing and communication capabilities,constrained energy resources and wireless communications.So that,wireless sensor networks are limited in life cycle,balance of energy consumption,security and trustworthiness.In this dissertation,we research on energy efficient clustering and routing algorithms,and trusted and effective security mechanisms.The main contributions of our work include:1)To solve the problems of the current distributed clustering algorithms in the wireless sensor networks with temporary CHs,we propose a distributed load balanced hierarchical clustering algorithm OLBHC.Without relying on central nodes,the sensor nodes can distributely determin its role(the cluster head or the cluster member)and the clustering structure.The determination of cluster heads is based on the residual energy of sensor nodes and the distance to other nodes.OLBHC defines three matrixes(DD,Flag,and FlagDis),which are related to clustering.Through the matrixes,OLBHC can assign balanced and appropriate member nodes for the CHs.Experiments show that the OLBHC has better load balance,longer life cycle and higher energy efficiency compared with existing algorithms.2)To solve the alone node problem of the current centralized clustering and routing algorithms in the wireless sensor networks with temporary CHs,we propose a centralized head preferred hierarchical clustering and routing algorithm GHPHC.The GHPHC algorithm contains two parts:clustering and routing.The clustering part applies the G-Means algorithm to divide the nodes into multiple clusters,and selects appropriate cluster heads by the proposed cluster head selection algorithm.The routing part applies the genetic algorithm to encode,and take the total distance and hop to the sink node as the fitness function.Compared with existing algorithms,the GHPHC algorithm can improve the energy efficiency and prelong the netowrk life cycle.3)We propose a genetic algorithm based energy-efficient clustering and routing algorithm GECR to solve the load unbalancing and low energy efficiency in the wireless sensor networks with permanent CHs.GECR algorithm merges the clustering and routing scheme into a same chromosome so that the total comsumed energy of all sensor nodes can be globally computed.For considering the energy efficiency and load balance at the same time,GECR take the total consumed energy and the virance of loads as the fitness function.Also,the experiments indicate that the presented designs can achieve better results.4)We propose a TPM based trust enhancement scheme TTES to solve the lack of a complete TPM bsed security policy in wireless sensor netowrks.Each CH is equipped with a trusted platform module TPM,which measures the integrity of various stages of the CH to ensure its trustworthiness.In addtion,TTES contains three efficient authentication protocols,denoted as SET-μTESLA,STEADY-μTESLA and SET-SCHNORR.SET-μTESLA and SET-SCHNORR establish mutual trusted relationships between CHs and CMs and reduce the iterations of hash function to improve energy efficiency.STEADY-μTESLA guarantees the validity of the identities of CMs when these nodes send the collected data to the corresponding CHs.The analysis demonstrates that TTES does well in resisting various attacks and simulation results show that TTES performs better than the existing secure schemes in terms of energy consumption and communication overhead.