BER Analysis for OFDM Systems with Various Modulation Techniques in Rayleigh Fading Channel

• Main Authors: Farzamnia, Ali, Moung, Ervin, Malitam, Bradly Virus, Haldar, Manas Kumar
• Format: Conference Proceeding
• Language: English
• Subjects: BER; Binary phase shift keying; Bit error rate; BPSK; DCT; DFT; Discrete cosine transforms; Discrete Fourier transforms; OFDM; QAM; QPSK
• ISSN: 2472-7555
• DOI: 10.1109/CICN.2018.8864950

Orthogonal Frequency Division Multiplexing (OFDM) is a form of multicarrier modulation technique that is the main technology used in 4G technology today. The current 4G OFDM technique however utilizes the Discrete Fourier Transform (DFT) and the Inverse Discrete Fourier Transform (IDFT) algorithm which uses carriers that are orthogonal to each other and changes the transmission of the signal from frequency selective channel to flat fading channel. Discrete Cosine Transform (DCT) however can also do the same with advantages in terms of bandwidth and computational speed. The performance of a DCT-based OFDM is thus interesting to have compared to that of traditional DFT-based OFDM. From the MATLAB simulation results, it was found that both DFT-based OFDM and DCT-based OFDM gives the best performance (low Bit Error Rate) when using Binary Phase Shift Keying (BPSK) when compared to Quadrature Phase Shift Keying (QPSK) and 4-Quadrature Amplitude Modulation (4-QAM). In addition, comparing the DFT-based OFDM and DCT-based OFDM, except for BPSK where DCT-based OFDM and DFT-based OFDM achieved the same BER, it was found that DCT-based OFDM gives better performance (lower BER) when using QPSK and 4-QAM compared to DFT-based OFDM.