الفهرس | Only 14 pages are availabe for public view |
Abstract In this thesis, a new trend in mitigating the peak power problem in OFDM system is proposed based on modeling the effects of clipping and amplifier nonlinearities in an OFDM system. Two criteria to reduce the dynamic range of the OFDM are proposed, namely, the generation of an OFDM signal with inherently small dynamic range through the choice of Modulation techniques when used with OFDM system results in lower PAR, without affecting the spectral efficiency and the error performance. And the use of Walsh Hadamard Transform (WHT) as an intelligent scaling factor to reduce the dynamic range of the OFDM signal without the risk of amplifying the noise when restoring the signal to its original level. Also the use of Huffman coding to reduce the PAR of an OFDM system is proposed. And finally, an OFDM transmitter with Huffman coding is built, for partial verification of the PAR reduction capability of Huffman coding when used with OFDM system on an FPGA a complete agreement with the simulation results in terms of the Complementary Cumulative Distribution Function CCDF (PAR) is found |