Traffic modelling and analysis of next generation networks.
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Date
2008
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Abstract
Wireless communication systems have demonstrated tremendous growth over the last decade,
and this growth continues unabated worldwide. The networks have evolved from analogue
based first generation systems to third generation systems and further. We are envisaging a
Next Generation Network (NGN) that should deliver anything anywhere anytime, with full
quality of service (QoS) guarantees. Delivering anything anywhere anytime is a challenge that
is a focus for many researchers. Careful teletraffic design is required for this ambitious project
to be realized. This research goes through the protocol choices, design factors, performance
measures and the teletraffic analysis, necessary to make the project feasible.
The first significant contribution of this thesis is the development of a Call Admission Control
(CAC) model as a means of achieving QoS in the NGN’s. The proposed CAC model uses an
expanded set of admission control parameters. The existing CAC schemes focus on one major
QoS parameter for CAC; the Code Division Multiple Access (CDMA) based models focus on
the signal to interference ratio (SIR) while the Asynchronous Transfer Mode (ATM) based
models focus on delay. A key element of NGN’s is inter-working of many protocols and
hence the need for a diverse set of admission control parameters. The developed CAC
algorithm uses an expanded set of admission control parameters (SIR, delay, etc). The
admission parameters can be generalized as broadly as the design engineer might require for a
particular traffic class without rendering the analysis intractable.
The second significant contribution of this thesis is the presentation of a complete teletraffic
analytical model for an NGN. The NGN network features the following issues; firstly, NGN
call admission control algorithm, with expanded admission control parameters; secondly,
multiple traffic types, with their diverse demands; thirdly, the NGN protocol issues such as
CDMA’s soft capacity and finally, scheduling on both the wired and wireless links. A full
teletraffic analysis with all analytical challenges is presented. The analysis shows that an
NGN teletraffic model with more traffic parameters performs better than a model with less
traffic parameters.
The third contribution of the thesis is the extension of the model to traffic arrivals that are not
purely Markovian. This work presents a complete teletraffic analytical model with Batch
Markovian Arrival (BMAP) traffic statistics unlike the conventional Markovian types. The
Markovian traffic models are deployed for analytical simplicity at the expense of realistic
traffic types. With CAC, the BMAP processes become non-homogeneous. The analysis of
homogeneous BMAP process is extended to non-homogeneous processes for the teletraffic
model in this thesis. This is done while incorporating all the features of the NGN network.
A feasible analytical model for an NGN must combine factors from all the areas of the
protocol stack. Most models only consider the physical layer issues such as SIR or the
network layer issues such as packet delay. They either address call level issues or packet level
issues on the network. The fourth contribution has been to incorporate the issues of the
transport layer into the admission control algorithm. A complete teletraffic analysis of our
network with the effects of the transport layer protocol, the Transmission Control Protocol
(TCP), is performed. This is done over a wireless channel. The wireless link and the protocol
are mathematically modeled, there-after, the protocols effect on network performance is thoroughly presented.
Description
Thesis (Ph.D.)-University of KwaZulu-Natal, Durban, 2008.
Keywords
Wireless communication systems., Theses--Electronic engineering.