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Lifetime Improvement of Wireless Sensor Network Based on Sleeping Algorithm

Wireless sensor network is one of the most powerful domain for research based on many characteristics that is power consumption, node failures, communication failures, large scale deployment , network problem, coverage problem .In this literature concentration goes towards network coverage problem as well as energy saving, Sleeping algorithm is used for randomly deployed WSN in order to increase the network lifetime. It offers good performance in terms of saving energy to increase the network lifetime in randomly deployed sensor network. In proposed system we are going to position the nodes in the network in such a way that, sleeping of node, if all its neighbors are awake should not result into blind point in network. We have also assumed that if node is at the centre of all neighbors, there is maximum probability that its sensing area is covered by its neighbors. Also, we are using remaining energy based sleeping algorithm to increase the lifetime of wireless sensor network. INTRODUCTION TO WSN Wireless sensor networks (WSNs) [1] consist of a large number of wireless sensor nodes that have sensing, data processing and communication functionalities. WSNs are typically used to monitor a field of interest to detect movement, temperature changes, precipitation etc. The nodes are typically equipped with power-constrained batteries, which are often difficult, expensive and even impossible to be replaced once the nodes are deployed. Therefore energy awareness becomes the key research challenge for sensor network protocols. The energy consumed by a node depends on its state. Each node may be in one of four states: transmit, receive, idle (when the node keeps listening to the medium even when no messages are being transmitted) and finally sleep state (where the radio module is switched off: no communication is possible). A wireless sensor network consisting of a large number of small sensors with low-power transceivers can be an effective tool for gathering data in a variety of environments. The data collected by each sensor is communicated through the network to a single processing center that uses all reported data to determine characteristics of the environment or detect an event. The communication or message passing process must be designed to conserve the limited energy resources of the sensors. Clustering sensors into groups, so that sensors communicate information only to cluster heads and then the cluster heads communicate the aggregated information to the processing center, may save energy. Network Lifetime and Coverage Problem Before introducing the proposed algorithm, the network lifetime and some related works are presented Wireless sensor networks are useful in military, scientific and environmental applications. Network lifetime and coverage are two important issues noticed by the researchers. In WSN [1] coverage can be defined as a measure of how well and for how long sensors are able to monitor the physical space. Nodes communicate [12] via RF signal using built-in antenna. Basically WSN’s are used for monitoring the field of interest to detect temperature changes, movements etc. S. Zairi et al: The coverage problem may be divided into three categories depending on what exactly that you are attempting to monitor. ‘Area coverage’ [4]: the overall goal is to have each location of the interest area within the sensing range of at least one node. ‘Target coverage’ [6]: observes a fixed number of targets. ‘Barrier coverage’ [7]: refers to the detection of movement across a barrier of sensors. In [12] the coverage idea is used as QoS metric for WSN. This idea is introduced to answer the fundamental question ,”How well the sensor can monitor the target area?”. Connectivity can be considered as the ability of the sensor nodes to reach the data sink. If the path is not present between the sensor nodes to data sink then collected data cannot be processed. Communication range of the node can be defined as the area in which another node can be located in order to receive data. Sensing range of the node can be defined as the area which can be monitored or observed by a node. The two ranges may be equal but are often different. Issues in Wireless Sensor Networks 1. Coverage Types Before deploying a wireless sensor network, the determination of area of interest that needs to be monitored is very important. The area of interest may be an entire area, set of targets or may be a breach among a barrier [9]. If every single point within the field of interest is within the sensing range of at least one sensor node then coverage area is known as full or blanket coverage. Ideally we expect the minimum number of sensors must be deployed in order to achieve blanket coverage [9]. 1 S. Zairi, B. Zouari, E. Niel, E. Dumitrescu “Nodes self-scheduling approach for maximizing wireless sensor network lifetime based on remaining energy” Published in IET Wireless Sensor Systems. Ranjeet Kagade et al, / (IJCSIT) International Journal of Computer Science and Information Technologies, Vol. 5 (1) , 2014, 16-19