الفهرس 
Chapter 1: IntroductionOnly 14 pages are availabe for public view
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Abstract
High Altitude Platform (HAP) is one of the most promising infrastructures for
realizing high data rate wireless communication systems in the near future. This thesis
investigates a survey on communication aspects of High Altitude Platforms, namely
airships or aircrafts flying at an altitude ranging between 17 and 22 km above the ground
in the stratosphere. The survey begins with an introduction to HAP, historical information
and advantages of HAPs compared to terrestrial and satellite networks, information about
suitable airships and aircrafts, frequency bands allocated to HAPs, possible architectures,
channel modeling and interference, antennas, transmission and coding techniques, access
and resource allocation techniques and the type of applications that HAPs are suitable for,
in addition to some related projects.
An essential problem need solving for the design of HAP communication systems
is to establish an effective channel model for predicting the characteristics of the
communication link. There have many papers on this problem and several channel models
have been proposed. We will summarize and analyze the channel models available. The
existing models are divided into three categories according to their respective specialties
and each channel model is briefly introduced with emphases on analysis of their strengths
and weaknesses.
A three-dimensional (3-D) analytical model for mobile-to-mobile, single input
single output (SISO), for terrestrial network is presented as a guided model for us. From
this model, the envelope Level Crossing Rate (LCR) and Average Fade Duration (AFD)
are derived for a 3-D non isotropic scattering environment.
We investigates the application of Multiple Input Multiple Output (MIMO)
techniques to HAP- based systems and proposes a Single Input Single Output
(SISO) 3 –D geometry-based single receive reference model for Ricean channels.
Since the model does not give us any information about the hand off velocities of
the transmitter and receiver and fading rate, accurate characterization of the
second order statistics, envelope level crossing rate (LCR) and average fade
duration (AFD) is necessary. from the analytical model, we derive the complex
faded envelope and from it we derive the envelope level crossing rate and
average fade duration for a 3-D non-isotropic scattering environment HAP
channel. The obtained numerical results are carried out to verify that the
assumptions made are applicable to the case of HAP model.