BER Analysis Of BPSK, QPSK, 16-QAM & 64-QAM Based OFDM System Over Rayleigh Fading Channel

Orthogonal frequency-division multiplexing (OFDM) is a method of encoding digital data on multiple carrier frequencies. The data are sent over parallel sub-channels with each sub-channel modulated by a modulation scheme such as BPSK, QPSK, 16 QAM etc. The advantage of OFDM is its ability to cope with severe channel conditions compared to a single carrier modulation scheme but still maintaining the data rates of a conventional scheme with the same bandwidth. Furthermore, channel equalization is simplified because OFDM may be viewed as using many slowly modulated narrow band signals rather than one rapidly modulated wide band signal. Also, the low symbol rate naturally makes the use of guard interval between symbols reducing ISI. Orthogonal Frequency Division Multiplexing has become one of the mainstream physical layer techniques used in modern communication systems. In this paper the OFDM system for a number of subcarriers is simulated and sent over Rayleigh fading channel. The performance of OFDM along with various modulation schemes in the Rayleigh Fading Channel environment is observed and presented in this paper.