Research On Data Compression Technology In Wireless Sensor Networks

Wireless Sensor Network(WSN)is the advanced network system which integrates dynamic monitoring,processing,transmission.It is composed of sensor nodes which has the capabilities of sensing,computing and communicating.On the base of the WSN,Wireless Multimedia Sensor Network(WMSN)which can collect data including video,image,sound and so on is proposed.These two networks which cover the advanced grid computing,intelligent storage,wireless communication play a important role in the field of military and civilian.But nodes in the network are powered by the battery whose energy is limited.Therefore,reducing the energy consumption of nodes to prolong the network lifetime is an important goal in the design of data compression technology.The data compression mechanism,transmission energy consumption and data compression algorithm of WSN are studied in the paper.The improved DP data compression algorithm of WSN and an improved CS compression algorithm of WMSN are proposed in order to improve the efficiency of energy use and prolong the network life cycle.The achievements are as follows:Firstly,in view of the existing problems of compression threshold(the limited difference)determined by the human which may cause error and the data is scanned too much in the DP compression algorithm.The DP algorithm is improved in this paper.The improved algorithm automatically sets the compression threshold according to the data trend and uses the method of data interval and the stack technology to compress the data,which achieves the aim of saving energy and improving the efficiency of compression.Secondly,in view of the existing problems of the performance and computational complexity of the observation matrix can not meet the requirements of the sensornodes which are subject to storage and energy constraints in the existing CS compression algorithm.The CS algorithm is improved in this paper.In the algorithm,a new observation matrix is constructed by using the orthogonal basis and the random Bernoulli vector and the generalized orthogonal matching pursuit algorithm is used to reconstruct the compressed data.The improved algorithm not only reduces the amount of transmission data but also achieves the purpose of improving the utilization ratio of the channel and reducing the energy consumption of the nodes.Finally,the results above are simulated and tested with Matlab.The simulation shows that the improved DP algorithm can effectively improve the compression accuracy and reduce the network energy consumption,which is more suitable for the WSN with limited energy and storage.The improved CS compression algorithm is better than the compression algorithm based on the Gauss observation matrix and the Toeplitz matrix in CR and Matching degree.