DESIGN OF ADAPTIVE MODULATION SYSTEM BY USING 1/3 RATE TURBO CODER (SNR Vs BER)

The improved BER was achieved by inhibiting 1/3 rated Turbo coder instead of 1/2 rated Turbo coder. It was accomplished by sending the output from 1/3 rated Turbo encoder to serial to parallel converter. The output from serial to parallel converter was inhibited to various Adaptive modulation schemes like m-aryPSK, m-aryQAM, m-aryCPM, and m-aryMHPM system. The modulated output was then fed to multiple access techniques like MCCDMA system and OFDMA system in fast fading Rayleigh environment. The BER performance was observed for both the MC-CDMA system and OFDMA system inhibiting various modulation schemes and the corresponding simulation results were plotted in Matlab and Simulink software.