Use of Query Control and Location for Routing in Mobile Ad Hoc Networks
Aarti Subhash Agarwal · OhioLink ETD Center (Ohio Library and Information Network) · 2002
A mobile ad hoc network is a collection of wireless mobile nodes dynamically forming a network without the use of any existing network infrastructure or centralized administration.As the nodes are mobile, the network topology is dynamic leading to frequent unpredictable connectivity changes.It is critical to route packets to destinations effectively without generating excessive overhead.This presents a challenging issue for protocol design since the protocol must adapt to frequently changing network topologies in a way that is transparent to the end user.A class of routing protocols called on-demand protocols has received a lot of interest because of their low routing overhead.In this thesis, we study techniques that can reduce this routing overhead even further.The on-demand protocols depend on query floods to discover routes whenever a new route is needed.Network-wide floods incur substantial overhead.Techniques have been proposed to contain the flood in a limited region where a route to the destination is highly likely to be found.Techniques have also been proposed to reduce redundant broadcasts.We propose various mechanisms to improve on these existing techniques.We propose adaptive mechanisms that utilize prior routing histories, mobility pattern and network load to choose the area in which the query flood should be contained.In addition, we propose a technique that utilizes the neighborhood information to reduce or eliminate redundant broadcasts.We evaluate their performances in isolation and in tandem.In the next part of the thesis, we turn our attention to use of location information i 5.1 A node at location A sends a DRM update.It again sends an update when it is at location B. This update is sent to only a close neighborhood as deviation from the actual trajectory is small.At C the update is sent to a larger neighborhood, but at D the update is sent network-wide as the deviation now is very large. . . . . . . . . . . . .64 5.2 Location Error vs. Dead Reckoning Threshold . . . . . . . . . . . . .68 5.3 Performance of DRM-based routing technique relative to AODV and DSR for 100 and 250 node networks with 40 CBR sources. . . . . . .