The chief function of wireless sensor networks is to forecast and collect the data from the main demesne, process the data and then transmit this data to the destination node. Now, for proper functioning, it requires some energy efficient mechanism so as to make paths between the source (sensor nodes) and the sink node. The path to be chosen should be in such a way so that the lifetime of the network is greatly increased. Wireless sensor network is emerging field because of its wide applications and least cost. It is a wireless network which subsist a group of small sensor nodes which communicate through radio interface. These sensor nodes are composed of sensing, computation, communication and power as four basic elements. But limited energy, communication capability, storage and bandwidth are the main resource constraints. In WSNs, Energy is a scarcest resource of sensor nodes and it determines the lifetime of sensor nodes. These are battery powered sensor nodes. These small batteries have limited power and also may not easily rechargeable or removable. Long communication distance between sensors and a sink can greatly drain the energy of sensors and reduce the lifetime of a network. In WSNs, energy is a big factor to be considered. Various techniques are used to optimize energy level of sensor nodes of WSN. In this paper, basics of WSN are discussed in terms of architecture of WSN and wireless sensor node. This paper also presents the types of WSN along with its challenges. As clustering is one of the techniques that can improve the efficiency of a node, so clustering and its parameters are also included in this paper.

WSN, Nodes, Energy, Communication, Efficiency, Clustering, Sensor, Network

[1] Beenish Ayaz, Alastair Allen, Marian Wiercigroch, “Dynamically Reconfigurable Routing Protocol Design for Underwater Wireless Sensor Network”, Proceedings of the 8th International Conference on Sensing Technology, Liverpool, UK, Sep 2-4, 2014.
[2] Ankita, “A Survey on Wireless Sensor Network based Approaches”, International Journal of Advanced Research in Computer Science and Software Engineering, Vol 4, Issue 4, April 2014.
[3] Stefanos A. Nikolidakis, Dionisis Kandris, Dimitrios D. Vergados and Christos Douligeris, “Energy Efficient Routing in Wireless Sensor Networks Through Balanced Clustering”, algorithms ISSN 1999-4893, Open Access, Algorithms, Pg- 29-42, 2013.
[4] Umesh B.N, Dr G Vasanth and Dr Siddaraju, “Energy Efficient Routing of Wireless Sensor Networks Using Virtual Backbone and life time Maximization of Nodes”, International Journal of Wireless & Mobile Networks (IJWMN), Vol 5, No.1, Feb 2013.
[5] Saraswati Mishra and Prabhjot Kaur, “Comparison of energy efficient data transmission approaches for flat wireless sensor networks”, International Journal of Advanced Smart Sensor Network Systems (IJASSN), Vol 4, Nov 3, July 2014.
[6] Avijit Mathur, Thomas Newe, “Comparison and overview of Wireless sensor network systems for Medical Applications”, Proceedings of the 8th International Conference on Sensing Technology, Liverpool, UK, Sep 2-4, 2014.
[7] S.Ranjitha and D. Prabakar and S. Karthik, "A Study on Security issues in Wireless Sensor Networks", International Journal of Computer Sciences and Engineering, Vol-03, Issue-09, Page No (50-53), Sep -2015.
[8] Amr M. Kishk, Nagy W. Messiha, Nawal A. El-Fishawy, Abdelrahman A. Alkafs, Ahmed H. Madian, "Proposed Jamming Removal Technique for Wireless Sensor Network", International Journal of Scientific Research in Network Security and Communication, Vol -03, Issue-02, Page No (1-14), Mar -Apr 2015