Performance Analysis of PDC over Rayleigh Fading Channel for OFDM System

In wireless communication systems diversity combining technique is one of the most important technique for combating the multipath effects of fading to improve the system's performance and to increase its channel capacity. This paper explores the post-detection-combining (PDC) diversity issues for orthogonal frequency division multiplexing (OFDM) over a Rayleigh fading channel. The performance of PDC for this OFDM system is analysed in terms of its signal-to-noise ratio (SNR) and bit error rate (BER) probability. The simulation results show that it SNR performance can be significantly improved using PDC, especially when the number of channel is large. In recent years, there has been a tremendous demand for reliable, high speed digital wireless communications. Besides the cellular phones, there are wireless modems, high definition television (HDTV), and digital radios. The performances of these devices in a wireless environment can be severely limited by random fluctuations in the amplitude of the received signal which is called fading. To answer this challenge, many innovative approaches have been developed. Among these diversity is commonly used in wireless communication for compensating the effects of multipath fading and to improve the system's performance. Large attenuation of wireless channel results in very poor performance. Our desired goal is to increase the SNR and reduce the BER. OFDM is a multicarrier modulation technique that's considered one of the most highly spectral efficient modulation techniques. Although its plays an important role in wide band transmission schemes, but its performance is degraded by multipath fading which is very common in any wireless communication system (et.al., 2000). To combat the effects of channel fading and to improve the system's performance, various diversity techniques are used in