Reducing Bit Error Rate in WiMAX using Spread Spectrum Techniques in Comparison with OFDM based Modulations

Abstract

This research investigated the Bit Error Rate (BER) performance of the WiMAX(Worldwide Interoperability for Microwave Access), a wireless system which uses IEEE 802.16 standard. For the implementation of OFDM model and analyzing the performance of WiMAX system using the Bit Error Rate (BER) and Signal to Noise Ratio (SNR) MATLAB software tool is used. We have used different adaptive modulation techniques such as QPSK, 16-QAM and 64-QAM and spread spectrum techniques such as FHSS (Frequency Hopping Spread Spectrum) and DSSS (Direct Sequence Spread Spectrum). In the current research the Bit Error Rate is improved by using spreading signals.  Spread spectrum enables a signal to be transmitted across a frequency band that is much wider than the minimum bandwidth required by the information signal.  The simulation results of this research show that FHSS and DSSS have given low BER at low SNR as compared to other modulation techniques.