A Modified Lempel Ziv Welch compressive data collection in Wireless Sensor Networks
M. Vijayalakshmi, Helen Victoria A. · International Journal of Engineering and Technology · 2018
Nowadays wireless sensor networks have wide applications in many fields such as medical, industrial, military, etc. Sensors are having limited processing capabilities and energy is an important constraint in wireless sensor networks as it determines the lifetime of the network.In a large scale wireless sensor networks, the sensor nodes have to collect more data when they are moving towards the sink.So the sensor nodes energy, nearer to the sink may get drained off more quickly and an alternate path has to be chosen which increases the delay in the network.Compressive data gathering is one of the techniques which reduce the data size, balance the energy in large scale wireless sensor networks.The existing technique takes more computations and increase in complexity on compressing the data.So a modified compressive data gathering protocol is designed which uses a lossless compression algorithm called modified Lempel Ziv Welch compression algorithm which is a simple and fast method for compressing the data.A tree is constructed and parent-children nodes are assigned and child node carries the compressed data and intermediate parent node aggregates and compresses it until it reaches the sink.The original data is reconstructed at the sink using Modified Lempel Ziv Welch decompression algorithm Index Terms -Wireless sensor network, data aggregation, MLZW compression and decompression.I. INTRODUCTION Wireless sensor networks consist of numerous autonomous sensors deployed in an environment to monitor physical or environmental conditions such as temperature, humidity etc.They transfer the data to a coordinating node for processing which acts as gateway to pass the data to sink.Each sensor node may consist sensing unit, processing, memory and microcontroller.The size of sensor nodes may vary from grain size to a shoe-box size depending upon the application in which it is used.Similarly, cost may vary from few to hundreds of dollars.The architecture and components of a wireless sensor node is shown in Figure : 1.1.Size and cost constraints of sensor results in resource constraints such as energy consumption, memory, bandwidth and speed.A wireless sensor network is an emerging technology nowadays, which plays an important role in creating a smart environment.It has huge applications in many fields such as environmental monitoring, natural hazard detection, military applications, health monitoring, forest monitoring, precision agriculture etc.