ii I am very happy and thankful to the staff of AIT-TC department, Ms Premma Rao, Mr. Rajesh Dehury and Mr.Jarook, for providing me the necessary things and equipment on happening hours and non-happening hours, throughout my research period. I thank all my friends from the department of TC & ICT, as well as people of AIT, for providing the love and support for the completion of my research.Last, but not the least, I would like to thank my parents and brother, for their constant encouragement, love and support, every single day.Best regards, V.Sandeep Reddy.iii ABSTRACT As we are moving towards smart homes and smart cities, the need for wireless sensors are increasing continuously. Most of the sensors are powered with batteries, which have limited amount of power. So, in a wireless sensor network, the main motive is to minimize the energy consumption and increase the lifetime of the network. Communication between the sensors and from sensors to sink is an energy consuming process. Here comes, the LEACH protocol, with the concept of clustering, that makes the network energy efficient and gives longer lifetime to the network. This LEACH protocol has many drawbacks. One among them is the uneven distribution of CHs in the network, in several rounds. This leads to higher consumption of energy by sensor nodes, which in turn reduces the stability period and also the overall lifetime of the network. This problem is solved to majority extent in this research by concept of dividing the sensor field into sub-regions and choosing cluster head from each sub-region. This modification reduces the uneven distribution of CHs to maximum extent. Modified protocol is simulated in MATLAB and its results show that, the stability period as well as overall lifetime is improved than existing basic LEACH protocol.iv