5G aims to be a revolutionary jump in terms of data rates, diminished latency, massive connectivity, the Internet of Things and so on. Right now, multicarrier modulation schemes are widely used because of their great advantages. One particularly famous modulation scheme is Orthogonal Frequency Division Multiplexing (OFDM), which is one of the most adopted technique in the world. We know that wireless channels are frequency selective, meaning that the frequency response of the channel varies according to the variation of the frequency with a sinusoidal behaviour. By dividing the available bandwidth into smaller bandwidths, we can approximate the channel as flat in each one of them.