IJSRD - International Journal for Scientific Research & Development| Vol. 2, Issue 08, 2014 | ISSN (online): 2321-0613 All rights reserved by www.ijsrd.com 103 Optimizing the Performance of I-mod Leach-PD Protocol in Wireless Sensor Networks Sheetal Dixit 1 Dr. Naraendra Yadav 2 Dr. Saroj Hiranwal 3 1 M.Tech. Scholar 1,2 Department of Computer Engineering 3 Department of Information Technology 1,2,3 Shri Balaji Technical Campus Abstract— Wireless Sensor Networks (WSNs) is a networks of thousands of inexpensive miniature devices capable of computation, communication and sensing. WSN is being been attracting increasing interest for supporting a new generation of ubiquitous computing systems with great potential for many applications such as surveillance, environmental monitoring, health care monitoring or home automation. In the near future, wireless sensor network is expected to consists of thousand of inexpensive nodes, each having sensing capability with limited computational and communication power which enables to deploy large scale sensor networks. Large scale WSN is usually implemented as a cluster network. Clustering sensors into groups, so that sensors communicate information only to cluster-heads and then the cluster-heads communicate the aggregated information to the base station, saves energy and thus prolongs network lifetime. LEACH (Low Energy Adaptive Clustering Hierarchy) protocol is one of the clustering routing protocols in wireless sensor networks. The advantage of LEACH is that each node has the equal probability to be a cluster head, which makes the energy dissipation of each node be relatively balanced. In LEACH protocol, time is divided into many rounds, in each round, all the nodes contend to be cluster head according to a predefined criterion. This paper focuses on how to set the time length of each round, how to adjust threshold based on the residual energy, and the measurement of energy required for transmission, based on the distance of cluster head from the base station, to prolong the lifetime of the network and increase throughput, which is denoted as the amount of data packs sent to the sink node. The functions of residual energy and required energy, and the time length of each round are deduced, thereby modifying the threshold value calculation. These functions can be used to enhance the performance of cluster-based wireless sensor networks in terms of lifetime and throughput. Key words: Wireless Sensor Networks, Network Lifetime, Energy Consumption, LEACH protocol, duty cycle I. INTRODUCTION Clustering sensors into groups, so that sensors communicate information only to cluster-heads and then the cluster-heads communicate the aggregated information to the base station, saves energy and thus prolongs network lifetime. Low Energy Adaptive Clustering Hierarchy (LEACH) [1] protocol is one of the clustering routing protocols in wireless sensor networks. The advantage of LEACH is that each node has the equal probability to be a cluster head, which makes the energy dissipation of each node be relatively balanced. In LEACH protocol, time is divided into many rounds, in each round, all the nodes contend to be cluster head according to a predefined criterion. This paper focuses on how to set the threshold limit of sensor node, to bias the probability of being selected as cluster head, to prolong the lifetime of the network and increase throughput, which is denoted as the amount of data packs sent to the sink node. The functions of lifetime and throughput related to the time length of each round are deduced. These functions can be used to enhance the performance of cluster-based wireless sensor networks in terms of lifetime and throughput. A. Problem Statement Leach Protocol is a dynamic clustering algorithm [2] for clustering networks. The primary motivation behind LEACH protocol is to distribute the power consumption in transmission evenly in all the nodes of the network. However, LEACH employs a purely random approach taking into consideration, only the case that no node can be elected as cluster head, which is elected as a cluster head in previous round. This work proposes an augmentation of the LEACH protocol with the residual energy of the node to bias the original cluster head selection and to distribute the energy consumption more evenly. II. MOTIVATION With the recent technological advances in wireless communications, integrated digital circuits, and micro electro mechanical systems (MEMS) [3], development of wireless sensor networks has been enabled and become dramatically feasible. Sensor nodes are often left unattended e.g., in hostile environments, which makes it difficult or impossible to re-charge or replace their batteries. This necessitates devising novel energy-efficient solutions [4] to some of the conventional wireless networking problems, such as medium access control, routing, self-organization, so as to prolong the network lifetime. Various routing, power management, and data dissemination protocols [5] have been designed for wireless sensor networks (WSNs) dependent on both the network architecture and the applications that it is designed for. In most of the applications sensors are required to detect events and then communicate the collected information to a distant base station (BS) where parameters characterizing these events are estimated. The cost of transmitting information is higher than computation and hence it is be advantageous to organize the sensors into clusters, where the data gathered by the sensors is communicated to the BS through a hierarchy of cluster-heads [6]. In wireless sensor networks (WSNs), due to the limitation of nodes’ energy, energy efficiency is an important factor should be considered when the protocols are designing. As a typical representative of hierarchical routing protocols, LEACH Protocol plays an important role. LEACH Protocol is the first protocol of hierarchical routings which proposed data fusion [7], it is of milestone significance in clustering routing protocols. Many