الفهرس 
chapter 1Only 14 pages are availabe for public view
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Abstract
worldwide interoperability for microwave access wimax uses orthogonal frequency division multiplexing OFDM as a multicarrier modulation technique because it is powerful in mitigating intersymbol interference isi. OFDM depends in its operation on fast fourier transform FFT adds a cyclic prefix CP at each symbol. this CP is a copy of the symbol end appended at the beginning on it which reduce the spectral efficiency. this leads to use discrete wavelet transform DWT rather than FFT to improve spectral efficiency.
DWT uses a filter bank or quadrature mirroe filter QMF which consists of low pass filter LPF and high pass filter HPF. it decomposs the signal into high frequency componets and low frequency components and then applies down sampling consequently, there is no need to use a CP which increase the spectral efficiency.