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.