Comparison of BER Performance of Various Adaptive Modulation Schemes in OFDM Systems

Objectives: The aim of future generation in mobile communication system is impeccably to integrate different types of real time services such as e-mail, speedy communication, video streaming and multimedia applications. Methods/Analysis: The proposed method for future generation is Adaptive Modulation of Orthogonally Frequency Division Multiplexing (AM-Orthogonal FDM) technique. Orthogonal FDM modulation scheme provide maximum data rate, robustness against multipath fading and bandwidth saving up to fifty percentage compared to existing one. The performance of the system is improved according to the channel fading conditions, adaptive modulation is employed in AM-OFDM. Findings: We consider in this research work various adaptive digital modulation techniques and compare the received Bit Error Rate (BER) vs. Signal to Noise Ratio (SNR) of the system in various adaptive modulation techniques with the proposed one. The existing adaptive systemshow the BER is 10-3.9 for 18 dB SNR, however the proposedtechnique show the BER is 10-5.7 for the same SNR value. The BER improvement of proposed oneis 98 percentage compared with existing method. Novelty/ Improvement: The novelty of proposed method isgood modulation method ofM-ary Phase Shift Keying is adapted, depending onthe currentchannel conditions measured by channel estimator and this information is fed back to the input.