Pramod Tripathi et al Int. Journal of Engineering Research and Applications www.ijera.com ISSN : 2248-9622, Vol. 4, Issue 3( Version 1), March 2014, pp.605-614 www.ijera.com 605 | Page Coverage In Presence Of Obstacles:A Survey Pramod Tripathi 1 ,Keyur Prajapati 2 ,Chetan Chudasama 3 1,2,3. Assistant Professor, Department Of Computer Engineering, MBICT, New VV Nagar (India). Abstract Wireless sensor networks have sparked immense research interest since the mid 1990’s. Ongoing improvements in affordable and efficient integrated electronic devices have put a great impact in the advancement of wireless sensor networks, which has enabled this field for a broad range of applications in battlefield surveillance, environment monitoring, industrial diagnostics, healthcare etc. Coverage which is one of the most important performance metrics for sensor networks resonates how accurately a sensor field is monitored. The coverage concept for a sensor field is accountable to a wide range of apprehensions due to a diversity of sensors and applications. Due to constrained resources for a sensor node it is valuable to construct a fully covered and energy efficient sensor network for real world applications. There are different conceptions that have been proposed based on the coverage type, deployment mechanism as well as network properties. This paper surveys research progress made to address various coverage problems in sensor networks. I present various coverage formulations and their assumptions as well as an overview of the solutions proposed. Keywords: wireless sensor networks, coverage problem, sensor, Network connectivity, Computational geometry, Network topology. I. Introduction We can define sensor as a device which sense the physical environment properties such as thermodynamics disturbances, sound waves generated in the environment, pressure generated over a place, magnetic force, a movement of object etc. and convert the parameter associated with the physical stimulus into signals that could be recorded, stored and processed. The form of signals could be electrical signals, mechanical signals etc. These signals are then converted into binary data which is referred as sensing data. Therefore the fundamental functional units associated with the sensor nodes are Power supply unit, which supplies power since sensor nodes are generally deployed at remote locations and are wireless in nature, Data storage unit to store the sensing data which is generated by sensing unit, Data processing unit to process the data generated by sensing unit to make it effective sensing data with minimum overheads and a Data transmission unit to transmit data to the peer nodes or sink. A Sensor network is the collection of different atomic nodes interacting together deployed over different geographical location. A sensor network also includes an interfacing unit called sink which receives the data collected by individual sensor nodes and transmit it to the master operating the sensor network. WSN is mainly distinguished from the conventional wireless ad hoc network by their unique and dynamic network topology. Sensor network has enumerable applications in the real world which includes Environmental monitoring under which habitat monitoring, integrated biology and structural monitoring are the prominent domains, Interactive and control under which pursuer-evader, Intrusion detection and automation are primary one. WSN is a great enabling technology that can revolutionize information and communication technology. Coverage is one of the performance metric of sensor network. It is one of the fundamental issues that arise in the sensor networks, in addition to localization, tracking and deployment. Coverage can be considered as the measure of quality of service of a sensor network. The goal is to have each location in the physical space of interest with the sensing range of at least one sensor. In many cases, we may interpret the coverage concept as a non negative mapping between the space points of a sensor field and the sensor nodes of a sensor network. Coverage problems could arise in different network stages. It is also formulated in various ways with different scenarios, assumptions and objectives. Researchers so far have worked significantly to do a more realistic theoretic background for coverage estimation. Several approaches with mathematical and simulation based proofs have been presented. All these approaches lead to a more efficient coverage over a sensing field. The most recent work that is gaining interest is the coverage in presence of obstacles .Determining coverage in presence of obstacles is an interesting task. In this paper I would like to dig about the approaches of determining coverage in presence of obstacles, the limitations of the approaches with future scope. The paper is RESEARCH ARTICLE OPEN ACCESS