Routing in ad hoc mobile networks: On-demand and hierarchical strategies

Mobile wireless communication is becoming increasingly popular due to recent advances in wireless devices and applications. A desirable capability of portable devices is the ability for communication between them. Collectively, these devices can form an ad hoc network. An ad hoc network is a group of mobile nodes with no fixed infrastructure; nodes communicate directly between one another over wireless channels. Because the transmission range of these nodes is limited, a routing protocol is needed to enable communication between them. However, because of the portable nature of these devices and the wireless transmission medium, ad hoc networks have many characteristics that render routing protocols designed for wired networks inapplicable.; This dissertation presents the Ad hoc On-Demand Distance Vector Routing (AODV) protocol. AODV is a reactive protocol in that it discovers routes only when they are needed by a source node. It provides unicast, multicast, and broadcast communication capability and is able to maintain routes even when the topology of the network is dynamic. AODV is well-suited for mobile wireless networks in that it has low processing and memory overhead, and low network utilization. Additionally, AODV provides loop freedom for all routes through the use of sequence numbers.; To improve the scaling potential of AODV, as well as that of many other reactive routing protocols, a set of hierarchical routing protocols has been developed. Hierarchical routing records routes logically across hierarchical levels, rather than across physical links. Hierarchical links tend to be longer-lived, and so these routes are more robust to node movement. This dissertation presents the Adaptive Routing using Clusters (ARC) protocol, as well as the Adaptive Routing using Cluster Hierarchies (ARCH) protocol. The former creates a one-level cluster structure across the network, while the latter can adjust dynamically the depth of the routing hierarchy in response to the network topology.; The performance of a protocol is not based solely upon its design. There are many other factors that contribute to the overall performance of the protocol. These factors include the density of the network, the MAC layer protocol selected, and the number of nodes in the network. Studies of these interactions are presented to determine their effect in ad hoc mobile networks.