Spectral Efficiency and Bit Error Rate Analysis of WiMAX Using Diverse Modulation Techniques over Rayleigh Channel

Worldwide Interoperability for Microwave Access (WiMAX) is a popular wireless technology which offers fast voice, video and information benefits up to the client end. In this paper, the OFDM based WiMAX physical layer makes use of concatenated Reed Solomon Convolutional (RS-CC) code and different modulation techniques with different code rates along with different cyclic prefix. As WiMAX can be used for NLOS (Non Line of Sight) communication so Rayleigh channel has been used as transmission medium. The comparison of various cyclic prefix such as 1/4, 1/8, 1/16 and 1/32 has been done on different modulation techniques over Rayleigh channel. The performance of OFDM based WiMAX physical layer has been analyzed from the graphs between BER (Bit Error rate) vs. SNR (Signal to Noise Ratio) and Spectral Efficiency vs. SNR (Signal to Noise Ratio) for different modulation techniques. The simulation results of BER vs. SNR conclude that different modulations and code rate provide better performance at guard time interval of 1/32.The simulation result of Spectral efficiency vs SNR conclude that 64 QAM with code rate 3⁄4 has highest spectral efficiency because of which it can be used for transmitting larger amount of data with lesser amount of transmission error.