Design and Implementation of OFDM System using QPSK & QAM

In this work, OFDM (orthogonal frequency division multiplexing) is analyzed for different transmission schemes on the basis of BER (Bit Error Rate), transmitting-receiving signal, constellation diagram and the best transmitting scheme is determined for OFDM. OFDM is analogous to Frequency Division Multiple Access (FDMA) in which the multiple user access is achieved by sub-dividing the existing spectrum into various channels, which are then allocated to users. In this paper Mat-lab simulation OFDM is used to see, how the Bit Error Ratio (BER) of a transmission varies when signal to Noise Ratio (S/N) and Multi-Propagation effect are altered to transmit a computer file in binary data from modulated by 16-QAM and QPSK modulation, finally at the end of the transmission, when the receiver receives the data, a comparison of the transmitted and the received messages is done in order to calculate the Bit Error Ratio (BER). © 2018 Walter de Gruyter GmbH, Berlin/Boston 2018.