Rearch On Network Connectivity Recovery And Mobile Data Collection In Wireless Sensor Networks

In recent years,wireless sensor networks(WSNs)have been widely used in many applications,such as environmental monitoring,medical treatment,search and rescue,etc.Sensor nodes are prone to failure due to energy depletion or the impact of harsh environment.The network will be divided into multiple disconnected partitions when the key nodes fail.In this case,the sensor nodes are unable to transmit data and cooperate with each other.Therefore,the research on restore the connectivity of the network and collect data from working nodes in time have become a hot research area.The connectivity restoration algorithm for networks with large scale nodes failure was studied firstly.The connectivity restoration algorithms proposed in recent years require many relay nodes.Moreover,the repaired network is prone to recurring failure.Therefore,a novel algorithm for restoring the connectivity of networks based on virtual point(RCVP)is proposed.The introduction of virtual points can make full use of the communication capabilities of the sensor nodes and relay nodes.Simulation results show that this algorithm can effectively reduce the number of required relay nodes and improve the robustness of the network.Secondly,the problem of mobile data collection in WSNs was studied.The main problem in the mobile data collection is to determine the mobile path of the mobile node.Although the single-hop data collection algorithm can effectively balance the traffic load between sensor nodes and prolong the lifetime of the network,the data collection delay is generally too large.In order to solve this problem,a data collection algorithm based on single hop in disconnected networks(DCSD)was proposed.In DCSD,this problem can be divided into two sub problems.One is determining the order in which mobile node visits each partition,the other is planning the moving path of mobile node within a partition.Two factors need to be considered when making decision on the staying positions.One is the degree of the neighbor nodes and the other is the number of connected graphs in the partitions.The length of the mobile path can be minimized with this algorithm.Simulation results show that the DCSD algorithm can effectively reduce the data collection delay and prolong the network's lifetime.