Performance of DQPSK-OFDM Systems Over Slowly Nakagami-m Fading Channels

This paper deals with the simulation of Nakagami fading in wireless channels using Orthogonal Frequency Division Multiplexing (OFDM) technique using Differential Quadrature Phase Shift Keying (DQPSK) modulation scheme. The paper proposes approximate methods for deriving Bit Error Rate (BER) in DQPSK-OFDM systems over frequency-selective Nakagami fading channels. The numerical results are plotted as BER Vs SNR for various values of Nakagami-m fading parameter ‘m’ and for various values of Doppler frequency shifts by using MATLAB software. The performance of Nakagami-m channel using DQPSK-OFDM technique is compared with that of the Nakagami-m channel without OFDM technique for various Doppler frequency shifts. It is observed that there is a decrease in the probability of error in Nakagami channels using OFDM technique compared to Nakagami-m channel without OFDM technique.