Performance Improvement of OFDMA Systems Through Wireless Communication Channels

The primary goal of this paper is to assess the performance of an Orthogonal Frequency Division Multiplexing Access (OFDMA) transmission system with a High Power Amplifier (HPA) at the transmitter edge. Differential Phase Shift Keying (DPSK) and Quadrature Amplitude Modulation (QAM) modulation techniques are used to generate the OFDMA signal. For modulation and demodulation, the Complex Wavelet Transform (CWT) is proposed instead of the Fast Fourier Transform (FFT). As a result, an algorithm is demonstrated that shows the effect of HPA on the modulated signal at the transmitter end. Reducing the high Peak to Average Power Ratio (PAPR) of an OFDMA signal is a difficult problem that is still being researched. As a result, the issue of PAPR performance evaluation in OFDMA systems is being investigated. As a result, a signal recovery algorithm is being researched in order to overcome the OFDMA system's limitation. This algorithm is based on detecting the highest peak. These peaks are estimated to be equal to the average value of the OFDMA signal as well as the detected peaks above the OFDMA signal's threshold limit. Furthermore, the results of the algorithm are compared to the results of the general clipping method. Bit error rate (BER) analysis is used to evaluate the performance of the transmitted OFDMA signal over fading channels. Rayleigh with Rician channel noise fading introduces the highest BER on the transmitted signal, according to the results. Furthermore, the accuracy of the highlighted algorithms is assessed using statistical measurements. The effect of contaminated channel impairments on the received modulated OFDMA signal, on the other hand, is investigated. As a result, recognizing the OFDMA signal is of primary importance. As a result, the Power Density Spectrum (PDS) and High Order Statistics (HOS) algorithms are proposed for identifying OFDMA signals.