الفهرس 
IntroductionOnly 14 pages are availabe for public view
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Abstract
Worldwide Interoperability for Microwave Access (WiMAX) is one of the choices for next
generation broadband wireless networks. It is based on the IEEE 802.16 wireless Metropolitan
Area Network (MAN) standards. It surpasses other wireless technologies in multipath
interference immune, efficient bandwidth (BW) usage, and offering higher data rates over
longer distances.
It uses the Orthogonal Frequency Division Multiplexing (OFDM) as a core modulation
strategy which is an elegant and effective technique for high speed transmission and
overcoming multipath distortion. OFDM systems enjoy several advantages such as; robust
against frequency selective fading channels and narrowband interference, high spectral efficiency,
Inter Symbol Interference (ISI) and Inter Carrier Interference (ICI) elimination, and
computational complexity reduction. On the other hand, OFDM systems suffer from two
main problems which are the high Peak-to-Average Power Ratio (PAPR) and the frequency
offset.
The high PAPR values affect the power amplifiers linearity. Consequently, they consume
more power and are less efficient. As a result, considerable effort must be made to
solve this problem, especially for mobile applications where power consumption is critical.
Many strategies are accomplished to reduce the PAPR, such as clipping, coding, Partial
Transmit Sequence (PTS), SeLective Mapping (SLM), Dummy Sequence Insertion (DSI),
etc. Unfortunately, some of them are not realizable and the others produce small PAPR
reduction.
In this work, four proposed systems are introduced. They offer high PAPR reduction
values with low hardware complexity. The first proposed system depends on replacing
the Inverse/ Fast Fourier Transform (I/FFT) blocks with Inverse/ Discrete Wavelet Transform
(I/DWT) blocks. The second recommended system employs a proposed block, called
i
ii
Constant Amplitude (CA) modulation, which converts the OFDM signal into bidirectional
square wave. Finally, the last two suggested systems utilize a proposed Wizard Amplitude
Shaping (WAS) encoder, which is used to convert any signal to an approximated triangle
wave.
For all the proposed systems, the whole characteristics mathematical analyses are presented.
Additionally, the complexity evaluations, reliability, In-band distortion; in terms of
Error Vector Magnitude (EVM), time and frequency domain behaviors, and PAPR values
are explained. Furthermore, the Bit Error Rate (BER) under Additive White Gaussian
Noise (AWGN) channel and multipath fading channels is tested. Also, the impacts of the
proposed schemes design parameters, are studied.
Additionally, the original OFDM system and all the proposed systems are implemented
over Field Programmable Gate Array (FPGA) kit. The VHSIC (Very High-Speed Integrated
Circuit) Hardware Description Language (VHDL) language is used for all implementations.
All designed codes are portable and don’t depend on the FPGA different technologies. Furthermore,
both hardware area and timing results are reported. Also, the timing simulations
are executed.