TDMA based wireless sensor network for military monitoring (MILMON)

Abstract

Wireless sensor network (WSN) is a new network family that enables to create smart environments. Although WSN has many application areas, military applications of WSN are very interesting. In this thesis, a new TDMA based sensor network for military monitoring (MILMON) is proposed. MILMON is developed to operate in large areas for acceptable lifetime periods. Design considerations of MILMON are energy consumption, delay, and fault tolerance. The main problems of TDMA based systems are time synchronization and time slot distribution. In order to realize MILMON, a new time synchronization mechanism (SyncHRT), a new distributed time scheduling mechanism (ft_DTSM) and data indicator slot mechanism (DISM) are proposed. Time synchronization with high range transmitter, SyncHRT is designed to minimize energy consumption and maximize precision. It assumes the existence of high range transmitter, so that many of the nodes can receive the broadcast signal of the high range transmitter. In this way, sensor nodes can be synchronized to a central point. Simulation model shows that SyncHRT can reduce energy consumption and increase precision. Another mechanism proposed for MILMON is delay sensitive, energy efficient and fault tolerant distributed slot assignment algorithm (ft_DTSM). It uses much less energy than the existing slot assignment mechanisms and it reduces delay with the convergecast traffic assumption which is very common traffic type for WSNs. Its fault tolerant structure helps to survive against single point of sensor node failures. Another mechanism proposed for MILMON is data indicator slot mechanism (DISM) which reduces energy consumption especially on low traffic requirements, as in most of the military monitoring systems. Analysis and simulation show that although there are WSN systems that perform better than our system for only energy consumption or for only delay, MILMON realizes an optimization on energy, delay and fault tolerance.