In this paper, the Bit Error Rate (BER), performance of conventional Discrete Fourier Transform (FFT) OFDM system is compared with Nonconventional Discrete Cosine Transform (DCT)OFDM system in AWGN and Rayleigh fading environment. Performance has been given with conventional mapping schemes like BPSK, QPSK and nonconventional mapping schemes like DQPSK and π/4 DQPSK. Simulation results show tha...