This study is based on the comparison of the results of an analysis recommended for the peak-to-average-power-ratio (PAPR) reduction methods. This is one of the most significant problems in the multiple input-multiple output-orthogonal frequency division multiplexing (MIMO-OFDM) systems. The information in the signals of the wireless communication systems can be given in the frequency domain [S.H. Han, J.H. Lee, IEEE Signal Proc. Lett. 11, 887 (2004)]. Of the methods applied for the PAPR reduction, which is one of the problems occurring in the frequency domain of the signals in MIMO-OFDM systems, the selective mapping (SLM) and the partial transmit sequences (PTS) are compared using a different approach. In the MIMO-OFDM systems, Fourier analysis is performed and the values of the signals on the frequency plane are taken although it is not clear which value of the signal at which time is taken [S.H. Han, J.H. Lee, IEEE Signal Proc. Lett. 11, 887 (2004)]. For the constant state of time, Fourier analysis approach is not appropriate for the detection of accurate frequency values. To solve this problem, a new wavelet transform-based (WT) analysis is recommended for the MIMO-OFDM systems with a new approach. It is shown that this analysis will be preferred instead of the Fourier analysis because of the optimization of the frequency-based temporary solutions of the signal. This approach of analysis is used along with the methods used for solving the PAPR problem in the MIMO-OFDM systems. Thereby, a comparison showing at which rate the methods for the solution of the problem contribute to solving the problem with this approach can be carried out. Numerical results show at which rate the methods with this approach can be carried out to contribute for solving the problem.