Performance analysis of FrFT based OFDM system with 1024-PSK and 1024-QAM modulation under various wireless fading channels

摘要

The problem of scarcity of spectrum had dealt with in this paper; by proposing an FrFT based OFDM system. The performance of system is measured at various values of α, where α is the fractional Fourier transform parameter. The proposed system with 1024-PSK modulation technique as compared to FFT based OFDM system, had achieved BER of 10~(-18.) at 53 dB SNR against 10~(-0.4) BER under AWGN channel, 10~(-2.5) and 10~(2.4) BER at 62 and 60 dB SNR respectively for Rayleigh and Rician channel respectively at α = 0.4 for AWGN and Rayleigh channel where as α = 0.2 for Rician channel. For Naka-gami channel proposed system had achieved BER of 10~(3.0) at 60 dB SNR as compared to 10~(-0.9) for same SNR at α = 0.9. With 1024-QAM modulation the proposed system had achieved BER of 10~(-2.9) at 14 dB SNR as compared to 10~(-0.5) for α = 0.9 under Rayleigh channel. For Rician and Nakagami channels the proposed system achieved BER of 10~(-1.9) and 10~(-3.0) at 10 and 14 dB SNR respectively as compared to BER of 10~(-0.4) for same SNR by FFT based system for α = 0.7 and α = 0.3 for Rican and Nakagami channel respectively.