Adaptive modulation based MC-CDMA system and adaptive modulation based OFDMA system are the two transmission systems which are best suited for future wireless communication ensuring large band width, high data rate and error free data communication. It is accomplished by sending the output from turbo-encoder to serial to parallel converter. The output from serial to parallel converter is inhibited to various adaptive modulation schemes like Mary-PSK, Mary-QAM, Mary-CPM, Mary-MHPM and Mary-GMSK Systems. The modulated output is then fed to multiple access techniques like MC-CDMA system and OFDMA system in fast fading Rayleigh environment. The BER performance, SNR Ratio and overall throughput is observed for both the MC-CDMA system and OFDMA system inhibiting various modulation schemes and the corresponding simulation results are plotted using Malab and Simulink software.