International Journal of Computer Applications (0975 – 8887) Volume 97– No.8, July 2014 22 Maintaining Consistency between Caches to Improve Overall Performance in Wireless Sensor Networks Harish Kumar Department of Electronics & Communication Engineering Lovely Professional University Phagwara, Punjab (India) Mritunjay Kumar Rai Department of Electronics & Communication Engineering Lovely Professional University Phagwara, Punjab (India) ABSTRACT Wireless Sensor Network (WSN) is an application based network. Wireless Sensor Network has a wide range of potential, practical and useful applications. Majority of such applications require an optimization to the communication among the sensors, so as to serve data in short latency and with minimal energy consumption. The sensor nodes in WSN are battery powered devices that consumes energy during data transmission and processing. Sink node send query messages in network, nodes may or may not reply back to the sinks query messages, but battery dissipates due to processing. Data transmission in WSN consumes more energy than processing therefore it is appropriate to exploit the benefits of caching. Cooperative caching is used for the reduction in the state of non utility of data and decreases the requirement of wireless bandwidth and energy. Cooperative caching which secure sharing of data among various nodes reduces the number of communications over the wireless channels and thus enhances the overall lifetime of a wireless sensor network. To overcome problem of cooperative cache a new technique is proposed which gives better results than existing one. Network simulator NS-2 is used for the simulations. Keywords WSN, Cooperative Caching, Cluster Head, CCL, CCF 1. INTRODUCTION Wireless sensor network (WSN) [1] is a self healing and self organizing networks. Self healing network enable nodes to reconfigure their link associations and find other pathways around powered-down nodes or failed nodes. Self organizing allows a network automatically join new node without the need for manual interference. In other words, wireless sensor is a computer network which is composed of a large number of sensor nodes. Sensor nodes are those which are capable of sensing environment around them. Sensor nodes are devices which are capable of gathering, storing, sensing and transmitting information. Sensor nodes can be deployed anywhere without install it. The gathered information can be retrieved. A wireless sensor network is collections of sensing device that can be wirelessly communicate. Each device is capable of talk to its peer, sense, process. It is centralized system. It is inexpensive to install and no wiring is required for data transfer. A wireless sensor network is a technology that provides monitoring. Wireless sensor play an important role in the processing of structural response data. In a wireless sensor networks nodes are organized in a cooperative manner [8]. Wireless sensor offers impressive computational resources for processing data. Wireless Sensor networks are self organizer and are deployed in ad-hoc systems. Each node in wireless sensor is consist of multiple types of memory and processing elements, RF transceiver, a power source, sensors and actuators. Wireless Sensor Network is a distributed real time systems. Wireless Sensor Network is a latest technology that has an ability to coordinate a large network into a single network. It is also consist of large number of low cost devices. Wireless Sensor Network is a Light weighted distributed system. There is no need of external infrastructures in wireless sensor network to communicate with other devices. The sensor in wireless sensor networks deployed are self organized and multi hop in nature. The wireless sensor networks consume a lots of energy while transfer data from one device to other. There is need to adjust transfer and sensing rate to avoid energy consumption in wireless sensor networks [5]. Wireless Access Points: The wireless access point acts as the central unit between the wired and wireless network. The wireless access points are basically the base stations which are attached to the wired network. Wireless Clients: Wireless clients are act as the network interface. The wireless clients are work with the various computer devices such as laptops, pc’s that communicate with the access points. In clustering, the sensor nodes are partitioned into different clusters. Every cluster is superintended by a node referred as cluster head (CH) and alternate nodes referred as cluster nodes. Cluster nodes don’t communicate directly with the sink node. They need to pass the collected data to the cluster head [9], Cluster head will aggregate the data collected, received from cluster nodes and forward it towards the base station. Therefore reduces the energy consumption and various messages communicated to base station. Further the paper is arranged as follows. Section 2 discussed on the cooperative caching schemes. Section 3 is discussed on the proposed methodology. In section 4 we have discussed the outputs and results of the proposed technique in comparison to the existed technique. 2. COOPERATIVE CACHING Cooperative caching is a technique, in which various sensor nodes share and coordinate cache data to overcome communication cost and use the total cache space of cooperating sensors. The simple assumption we make, is that each sensor node has a moderate local storage capacity