Research And Design Of Routing Protocols For Wireless Sensor Networks

Wireless sensor networks (WSNs) have attracted a wide range of disciplines where closeinteractions with the physical world are essential. The distributed sensing capabilities and theease of deployment provided by a wireless communication paradigm make WSNs animportant component of our daily lives. By providing distributed, real-time information fromthe physical world, WSNs extend the reach of current cyber infrastructures to the physicalworld. WSNs consist of tiny sensor nodes, which act as both data generators and networkrelays. Each node consists of sensor(s), a microprocessor, and a transceiver. Through the widerange of sensors available for tight integration, capturing data from a physical phenomenonbecomes standard. Through on-board microprocessors, sensor nodes can be programmed toaccomplish complex tasks rather than transmit only what they observe. The transceiverprovides wireless connectivity to communicate the observed phenomena of interest. Sensornodes are generally stationary and are powered by limited capacity batteries. Therefore,although the locations of the nodes do not change, the network topology dynamically changesdue to the power management activities of the sensor nodes. To save energy, nodesaggressively switch their transceivers off and essentially become disconnected from thenetwork. In this dynamic environment, it is a major challenge to provide connectivity of thenetwork while minimizing the energy consumption. The energy-effcient operation of WSNs,however, provides signifcantly long lifetimes that surpass any system that relies on batteries.Recent advances in wireless sensor networks have led to an emergence of many routingprotocols. Limited battery capacity of sensor nodes makes energy efficiency a major andchallenge problem in wireless sensor networks. Thus, the routing protocols for wireless sensornetworks must be energy efficient in order to maximise the network lifetime. In this thesis, wedeveloped a centralized clustering, energy-efficient routing protocol for wireless sensornetworks. Our protocol consists of a cluster head selection algorithm, a cluster formationscheme and a routing algorithm for the data transmission between cluster heads and the basestation. The cluster head selection algorithm is performed by the base station using globalinformation of the network. This algorithm aiming at choosing cluster heads that ensure boththe intra-cluster data transmission and inter-cluster data transmission are energy-efficient. Thecluster formation scheme is accomplished by exchanging messages between non-cluster-headnodes and the cluster head to ensure a balanced energy load among cluster heads. The routingalgorithm is based on the optimal transmission range for the data transmission between clusterheads and the base station using multi-hop. The performance of our routing protocol isevaluated by comparing with three existing routing protocols on a simulation platform. Thesimulation results show that our protocol can achieve better performance in terms of energy efficiency and network lifetime. Because of the centralized algorithm and multi-hop routing,there is a small communication overhead and transmission delay when using our protocol.Since our protocol can save energy and prolong network lifetime, it is well suited forapplications where energy and network lifetime are the primary considerations and smalloverhead and time delay can be tolerated.