Gugrajah_Yuvaan_ Ramesh_2003.pdf
Gugrajah_Yuvaan_ Ramesh_2003.pdf
Gugrajah_Yuvaan_ Ramesh_2003.pdf
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Conclusion<br />
Chapter 6<br />
Results for packet delivery ratio and average end-to-end delay are obtained and show<br />
the new protocol performs better than the other protocols compared in all scenarios<br />
where there is high mobility and high offered load. This shows that load balancing in<br />
ad hoc networks is beneficial under certain circumstances. However, once again the<br />
computational cost of implementing more complex routing protocols need to be<br />
weighed against the benefits. Under low offered loads, the less complex AODV<br />
routing protocol performed almost as well as the DLAR protocols.<br />
This dissertation also proposes an analytical model for the evaluation of the blocking<br />
probability of a call offered to an ad hoc network that results from a particular<br />
routing protocol being implemented. All of the comparisons of the routing protocols<br />
are performed using simulators, which are not only time consuming but also do not<br />
allow as rapid optimisation of routing protocols by a network designer as would<br />
analytical models. Techniques for modelling fixed networks as loss networks are<br />
combined with those for the evaluation of cellular CDMA networks. CDMA was<br />
chosen because CDMA systems offer high spectrum efficiency and the potential use<br />
of advanced antenna and receiver structures. No previous work has been published<br />
on the type of full-scale analytical evaluation of ad hoc networks that is consider in<br />
this dissertation. Numerical results obtained provide a 3.9 % error as compared to<br />
simulation results of a similar network, with the analytical model providing a more<br />
conservative estimate.<br />
While the results of the analytical model compare favourably to simulation results, a<br />
major shortcoming of the analytical model proposed is the inability to account for<br />
mobility. Due to the potential number of topological configurations possible, all<br />
routes cannot be accounted for. The analytical model therefore is only capable of<br />
evaluating fixed wireless multihop ad hoc networks. Networks of this sort include<br />
wireless local loop extensions to the fixed wired telephone network in rural areas.<br />
Methods for evaluating and optimising routing protocols using the analytical model<br />
are demonstrated.<br />
6-3