Effective Cache based Policies in Wireless Sensor Networks: A Survey

ABSTRACT The sensor nodes in Wireless Sensor Network are battery powered devices which consumes energy during data transmission, processing, etc. The critical task in WSN is to deal with optimizing power consumption. One possible way to minimize power consumption is by the use of caching the data. Generally data transmission in WSN consumes more energy than processing, so it is good to utilize the benefits of caching so that data access can be made faster. Caching, if used efficiently, could reduce overall network traffic and hence bandwidth can be optimally utilized. In this paper we are reviewing the various data caching techniques in WSNs. This paper aims at future research work and provide researcher with helpful guidelines. Keywords Caching, Wireless Sensor Networks, Energy Efficiency. 1. INTRODUCTION recent developments in making energy effThe icient Wireless Sensor Network [1-2] is giving new direction to deploy these networks in applications like surveillance [3-5], industrial monitoring [6], traffic monitoring [7], habitat monitoring [8], cropping monitoring [9], crowd counting [10], etc . The growing use of these networks is making engineers to evolve innovative and efficient ideas in this field. A lot of research in data routing, data compression and in-network aggregation has been proposed in recent years. One of the major factors that could help in building an efficient Wireless Sensor Network is by the use of caching. To best of our knowledge, few research has been done in making an energy efficient Wireless Sensor Network utilizing the benefits of caching the data. Caching is a technique which provides faster data access in any computing system. With the discovery of cache the accessibility of data has been increased as it stores data to be needed in future and can be retrieved rapidly. Caching [11] has made its impact in the Wireless sensor networks also. A wireless sensor network consists of a large number of nodes [12] spread over a specific area where we want to look after at the changes going on there. A sensor node generally consists of sensors, actuators, memory, a processor and they do have communication ability. All the sensor nodes are allowed to communicate through a wireless medium. The wireless medium may either of radio frequencies, infrared or any other medium, of course, having no wired connection. These nodes are deployed in a random fashion and communicate within to make an ad-hoc network. If the node is not able to communicate with other through direct link, i.e. they are out of coverage range of each other, the data can be send to the other node by using the nodes in between them. This property refers to multi-hoping. Generally WSNs are not centralized one as there is peer-to-peer communication between the nodes. So there is no requirement of prior established infrastructure to deploy the network. WSN gives flexibility of adding nodes and removing the nodes as required. But this gives rise to many drastic changes to deal with in the network topology such as updating the path, or the network tree, etc. In a WSN the node that gathers the data information refers to sink. The sink may be connected to the outside world through internet where the information can be utilized within time constraints.