Gugrajah_Yuvaan_ Ramesh_2003.pdf

ABSTRACT
An ad hoc network is a multi-hop wireless network in which mobile nodes
communicate over a shared wireless channel. The network is formed cooperatively
without specific user administration or configuration and is characterised by a
distributed network management system and the absence of a wired backbone.
Military, law enforcement, and disaster relief operations are often carried out in
situations with no pre-existing network infrastructure and can benefit from such
networks because base stations, which are single points of failure, are undesirable
from a reliability standpoint. The rising popularity of mobile computing has also
created a potentially large commercial market for multimedia applications applied
over wireless ad hoc networks.
This dissertation focuses on the routing aspects of ad hoc networking. The multi-hop
routes between nodes constantly change as the mobile nodes migrate. Ad hoc
network routing algorithms must therefore adapt to the dynamic and unpredictable
topology changes, the random radio propagation conditions and portable power
sources. Various routing protocols have been proposed in the literature for ad hoc
networks. These protocols together with comparative simulations are discussed and a
new protocol based on load balancing and signal quality determination is proposed
.and the simulation results are presented.
Currently the proposed routing protocols are compared using simulation packages
which are often time consuming. This dissertation proposes a mathematical model
for evaluating the routing protocols and the resultant end-to-end blocking
probabilities. The mathematical model is based on a derivation of the reduced load
approximation for analysing networks modelled as loss networks and the evaluation
incorporates and adapts models that have been used for the analysis of cellular Code
Division Multiple Access (CDMA) systems. While analytical methods of solving
blocking probability can potentially generate results orders of magnitude faster than
simulation, they are more importantly essential to network sensitivity analysis,
design and optimisation.
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