The Nguyen Thai Hoang creator Fernando, W.A.C. Chairperson Ahmed, Kazi Mohiuddin Examination Committee Teerapat Sanguankotchakorn Examination Committee Viet Nam Post and Telecommunications (VNPT) Scholarship donor text series technical report th Pathum Thani, Thailand Asian Institute of Technology 2003 continuing eng 44 leaves Orthogonal Frequency Division Multiplexing (OFDM), which is a modulation technique for multicarrier communication systems, is a promising candidate for 40 systems since it is less susceptible to intersymbol interference (ISI) introduced in the multipath fading channel. But with appearing of spectral nulls in transmission line, the performance of OFDM systems can be degraded. Therefore, Precoded and Vector OFDM systems are proposed to improve the performance of the OFDM systems in spectral null channel. In addition, beside many of its advantages, OFDM has two major disadvantages: high Peak to Average Power Ratio (P APR) and frequency offset. Hence, the issue of PAPR reduction in POFDM and VOFDM systems is investigated in this research study. P APR of conventional OFDM, POFDM and VOFDM are analyzed with PTS and ESA algorithms. Simulation results show ESA can gain up to 3.5 dB compared to the PTS. BER performance is also investigated for all three systems and results suggests that ESA with 0.8 scaling factor and PTS perform equally in a multipath fading channel with 4 taps. Therefore ESA is a better algorithm to reduce P APR in OFDM, POFDM, and VOFDM systems. A research study submitted in partial fulfillment of the requirements for the degree of Master of Engineering, School of Advanced Technologies Research report (M.Sc.) - Asian Institute of Technology, 2003 Data transmission systems Multiplexing Asian Institute of Technology. http://203.159.5.9/ait-thesis/detail.php?q=B08379 http://203.159.5.9/ait-thesis/detail.php?q=B08379 030507 20260818171540.0