BER Performance Criteria Based on Standard IEEE 802.11a for OFDM in Multipath Fading Environments

In this paper, the BER performance of OFDM-BPSK 16--QAM and 64--QAM system over various multhipath fading channel has been reported. Orthogonal Frequency Division Multiplexing (OFDM) is a key technique for achieving high data rates and spectral efficiency requirements for wireless communication systems. However in fading environments the bit error rate (BER) increases. The performance can be improved by using some kind of channel coding. This form of OFDM is called coded-OFDM (COFDM). The theoretical approximate calculation is also analyzed of BER for binary phase shift keying (BPSK) and quaderature amplitude (QAM) modulation schemes in OFDM systems. In addition, the method of BER calculation is validated by simulations. Fading channel severely degrade the performance of the wireless communication systems. Most of the wireless communication systems require knowledge of the channel Signal-to-Noise ratio. This paper presents a modeling and simulation of OFDM based on IEEE 802.11a standard. The flexibility of this model is because fading parameters compared to three fading model, which helps to analyze the severity of fading more deeply and this model is versatile enough to represent fading. Finally simulations of OFDM signals are carried with AWGN, Rayleigh and Rician faded signal to understand the effect of channel fading. The performance of OFDM is compared in terms of BER vs SNR for different modulation formats.