| This thesis is a collection of research on the fundamental network behaviors of mobile ad hoc networks. The first part of this thesis focuses on mobile infostation networks, a new class of mobile ad hoc network that exploits node mobility to improve network capacity. We address three important problems, namely the effect of node noncooperation, transmit range and node mobility on network performance.; The issue of node noncooperation is examined in the context of a content distribution application. When two nodes are in proximity, they negotiate for a file exchange in accordance to a social contract. An exchange is warranted only when each node can obtain something it wants from the exchange. Both common interest and dissimilar interest models are examined. The performance of different user strategies are evaluated through analysis and simulations.; The effect of transmit range on network capacity is then examined under a realistic interference model. Four transmission strategies are analysed and we show that a stipulated transmit range improves the capacity compared to the Grossglauser-Tse strategy. The optimal number of neighbors is determined, which is much smaller than the magic number of 6 to 8 neighbors for multihop networks. In addition, the capacity per unit area of the strategies is shown to increase linearly with node density.; We have also examined the effect of node mobility on highway mobile infostation networks via a novel highway model. Using arguments from renewal reward theory, the long run data rate of an observer node can be derived. For node speed that is uniformly distributed, we show that the data rate is independent of observer node speed in reverse traffic. In forward traffic, we show that the data rate increases with observer node mobility.; In the second part of the thesis, we focus on multihop ad hoc networks, in which nodes communicate in multihop routing. We have investigated the effect of transmit range on energy efficiency of packet transmissions, and determine a common range for all nodes such that the average energy expenditure per received packet is minimized. Both stationary and mobile networks are considered. The dependence of energy efficiency on various system parameters is investigated.; We also examined the network behavior of a routing algorithm for multihop ad hoc networks. By using an alternate graphical interpretation of simulation results, inter-relationships between performance metrics and system parameters are revealed. These observations often give us insights to the mechanisms that underlie the network behavior. |
