Routing in mobile ad hoc networks: Scalability, resource management and application.

摘要

A mobile ad hoc network (MANET) is a best effort, multiple hop datagram-forwarding network, consisting of mobile nodes interconnected by wireless links. In most envisioned MANET scenarios, there is little or no existing network infrastructure and adaptive communication between mobile nodes is required. The mobility of network nodes, the variability of wireless link quality and the lack of hierarchical structure in the physical topology of the network makes routing in MANETs arguably much more difficult than in wired networks.; The focus of this dissertation is routing in MANETs. First, the scalability of MANET routing protocols with respect to increasing node count is considered. Hierarchical techniques are proposed to enhance scalability. A detailed analysis is undertaken to access the control overhead of hierarchical routing. An important result of the analysis is that hierarchical routing control overhead may be reduced to a figure that is as small as polylogarithmic in the node count.; Second, the concept of resource management in MANEs is considered. The analysis of hierarchical routing control overhead shows that by adjusting the number of levels in the routing hierarchy, network implementers can flexibly trade increased routing complexity for reduced control overhead and visa versa. As another instance of resource management, a heuristic is presented to facilitate a flexible tradeoff between route acquisition delay and control overhead for flood-search on-demand routing protocols.; Third, application of the MANET routing paradigm is considered. It is envisioned that the features of adaptability, spatial reuse and energy efficiency will allow MANETs to be a viable option for designers of wireless networks in the near future.; A key finding of this thesis is that although there are scalability issues with respect to user throughput in MANETs, it is possible to devise routing protocols that are scalable. This suggests that in order to fully exploit scalable routing techniques, it is necessary to organize user communication sessions in a hierarchical manner so that the prevailing traffic pattern also scales well with the MANET architecture.