The purpose of this study is to improve the basic understanding of the propagating mechanisms behind seismic interference noise. A Matlab code of the normal mode solution in Pekeris waveguide model was developed and numerical simulations were done. The collection of data was examined carefully and a small subset was chosen for further analysis and comparison with numerical simulations. Comparison of the output from this modeling code in the far-field with real noise recordings in case of a slanted-streamer was performed. From the simulations it is observed that the rate of dispersion, attenuation and the transmission loss depend on both mode number and range. For both simulated and real data it is observed that, following the dispersive character of the waveguide seen, the higher frequencies significantly more attenuated than the lower ones. It was also shown that the real noise recordings locally looked similar to the simulated data. Thus, indicating SI noise show close resemblance with dispersive modes. However, one main difference exists between simulated and recorded data; the latter has much longer time duration. The unknown representation of the position of the source and the inhomogeneity of the water column could be the possible reason for this difference.