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AHMED GHULAM MUSTAFA SABER
KARAM
Department of Networking
College of Information Technology
Title
Development of An Efficient Ad Hoc Broadcasting Scheme for Critical Networking Environments
Faculty Advisor
Prof. Liren Zhang
Defense Date
09 May 2016
Abstract
Mobile ad hoc network has been widely deployed in support of the communications in hostile environment
without conventional networking infrastructure, especially in the environments with critical conditions such
as emergency rescue activities in burning building or earth quick evacuation. However, most of the existing
ad hoc based broadcasting schemes either rely on GPS location or topology information or angle-of-arrival
(AoA) calculation or combination of some or all to achieve high reachability. Therefore, these broadcasting
schemes cannot be directly used in critical environments such as battlefield, sensor networks and natural
disasters due to lack of node location and topology information in such critical environments. This research
work first begins by analyzing the broadcast coverage problem and node displacement form ideal locations
problem in ad hoc networks using theoretical analysis. Then, this research work proposes an efficient
broadcast relaying scheme, called Random Directional Broadcasting Relay (RDBR), which greatly reduces
the number of retransmitting nodes and end-to-end delay while achieving high reachability. This is done
by selecting a subset of neighboring nodes to relay the packet using directional antennas without relying
on node location, network topology and complex angle-of-arrival (AoA) calculations. To further improve
the performance of the RDBR scheme in complex environments with high node density, high node mobility
and high traffic rate, an improved RDBR scheme is proposed. The improved RDBR scheme utilizes the
concept of gaps between neighboring sectors to minimize the overlap between selected relaying nodes
in high density environments. The concept of gaps greatly reduces both contention and collision and at
the same time achieves high reachability. The performance of the proposed RDBR schemes has been
evaluated by comparing them against flooding and Distance-based schemes. Simulation results show
that both proposed RDBR schemes achieve high reachability while reducing the number of retransmitting
nodes and end-to-end delay especially in high density environments. Furthermore, the improved RDBR
scheme achieves better performance than RDBR in high density and high traffic environment in terms of
reachability, end-to-end delay and the number of retransmitting nodes.
Dissertation