HYBRIDIZATION OF MAC PROTOCOLS AND DEVELOPMENT OF A BATTERY BOOSTIMG DEVICE FOR WIRELESS SENSOR NODES

Abstract

Majority of people in India depend upon railways as their mode of transportation. It is very important that railways are made safer to travel. Recently, there have been a few accidents due to poor maintenance of the tracks and coaches. Manual monitoring and regular inspection of railway lines and coaches by skilled labour is very time consuming and expensive. Wireless sensor networks (WSNs) have the capability to address these issues. With WSN deployed in rail coaches, they can continuously monitor the interaction of the coach with the rail lines. This data can be analysed to nd out precise faults in real time and hence can make maintenance more a ordable and e ective. One of the threats to WSN is the limited battery life of the sensor nodes. The battery in nodes needs to be recharged/replaced frequently. This thesis proposes a battery boosting device that can increase the usable lifetime of the nodes as well as the network. This dissertation proposes hybridization of medium access control (MAC) protocols based on the tra c conditions. The WSN switches between two existing protocols i.e. EA-TDMA and E-BMA depending on whether there is medium to high or very high tra c respectively. Data tra c in a WSN depends on the rate at which the data is sampled and trans- mitted over the network. Keeping a xed sampling rate may lead to oversampling when the train is moving at low speed. To overcome this limitation, this dissertation proposes a speed dependent sensor sampling method. The three aforementioned techniques are implemented in hardware to test the per- formance in a practical WSN environment. It is found that the combination of three approaches can increase the lifetime of sensor nodes by approximately 30% in real-time scenario.