Abstract—Orthogonal Frequency Division Multiplexing(OFDM) has become the most widely used signal carrier platform for many wireless transmission technologies. Since OFDM uses multiple sub-carriers in transmitting its signals with each sub-carrier mostly modulated using phase modulation, choosing the best phase modulation scheme is paramount to its optimal performance. Quadrature Phase Shift Keying (QPSK) is popularly used for OFDM sub-carrier modulation and it has proven to be quite stable and reliable. This paper compares OFDM’s performance using QPSK alongside one of its variant, π/4-QPSK, especially when passed through a noisy channel, which is simulated using MATLAB’s Additive white Gaussian noise (AWGN) channel.

Index Terms—OFDM, QPSK, π/4-QPSK, etc.

The authors are with the School of Information Technology and Communication, American University of Nigeria, PMB 2250, Yola,Adamawa State, Nigeria (e-mail: babatunde.ogunleye@aun.edu.ng,ogunleye.babs@gmail.com).

Cite: Babatunde Ogunleye, Lawrence Oborkhale, and Olusegun Ogundapo, "Comparative Analysis of OFDM Sub-Carrier Modulation Using QPSK and π/4-QPSK," International Journal of Computer and Communication Engineering vol. 1, no. 3, pp. 273-276 , 2012.