Performance of Multi-Amplitude Minimum Shift Keying (N-MSK) with Orthogonal Frequency Division Multiplexing (OFDM)

Multi-carrier transmission, especially orthogonal frequency division multiplexing (OFDM), has gained interest due to its advantageous properties for mobile radio channels. Obviously, as a multi-carrier modulation technique, it's inherently high Peak to Average power Ratio (PAR) is one of the most obstacles facing OFDM to be used for mobile wireless applications. In this paper we introduce a novel approach to solve this problem by using one of the continuous phase modulation techniques, which is the MSK in OFDM, and we will extend to N-MSK for boosting the spectral efficiency and maintaining PAR in an acceptable range. Finally, we prove that the use of N-MSK into OFDM has numerous advantages compared to the conventional use of M-QAM into OFDM through Matlab simulations of the proposed system models to compare between MSK and N-MSK (N=2, 3, 4) to be used for OFDM. Also we highlight the benefits of using N-MSK over M-QAM Modulators into OFDM with the same spectral efficiency.