الفهرس 
Wireless Broadband and WiMAX NetworksOnly 14 pages are availabe for public view
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Abstract
Worldwide Interoperability for Microwave Access (WiMAX) technology
is presently one of the most promising global telecommunication systems.
It considers a Broadband Wireless Access System and has numerous
applications. The technology is based on the IEEE 802.16 standard. The
standard defines two basic operational modes: point-to-multipoint and
Mesh. The Mesh mode provides two scheduling algorithms for assigning
time slots to each network node: centralized and distributed.
The distributed mode offers many additional advantages, such as increased
network throughput, scalability and coverage. However, this mode lacks
Quality-of-Service (QoS) support as it lacks traffic classification compared
with the point-to-multipoint mode which was developed with quality-ofservice
in mind. The point-to-multipoint mode introduces five different
service classes for handling different applications based on their qualityof-service
constraints.
The aim of this thesis is to address the QoS problem in coordinated
distributed scheduling in IEEE 802.16 Mesh mode. The thesis proposes a
novel architecture for QoS-aware IEEE 802.16 Mesh node; the
architecture relies on providing a classifier and data queues for different
traffic types. The proposed node classifies the traffic based on the Type of
Service (ToS) or Differentiated Service Code Points (DSCP) field in the IP
header. The thesis explains the new mechanism proposed in mapping the
QoS parameter from the IP layer to the IEEE 802.16 MAC layer to
achieve cross layer QoS. a new technique is introduced to assign the data
minislots based on’ traffic types to satisfy the requirements of different
applications such as high-data-rate delay-sensitive applications, low-datarate
applications and bursty traffic over the Internet. Another aspect
discussed in the thesis is achieving fairness in distributing the data
minislots among the requests received by each node while maintaining the
QoS parameters required.
Several simulations are performed using OPNET Modeler 16.0 to evaluate
the proposed architecture and the important system parameters which
affect the network perf ormance. The evaluation showed a significant
enhancement in the performance of the network regarding quality of
service when using the proposed node architecture, especially in the endto-end
delay and the serving ratio (data minislot assignment).
The thesis is organized as follows; Chapter One presents the wireless
broadband technologies and gives an introduction to the IEEE 802.16
standard, their main features and the IEEE 802.16 protocol stack. Chapter
Two presents the Mesh topology, its specification and features. Chapter
Three focuses on the QoS challenge facing the Mesh Network giving a
proposal for a solution that can enhance the performance of the distributed
Mesh mode. Chapter Four explains the simulation model used to evaluate
the proposed solutions. Chapter Five presents the simulation model results
and their analysis. And finally chapter Six concludes the results followed
by suggestions for future work related to this thesis.