r share common oxygen absorption loss) are transformed into frequency-domain channel response and the oxygen absorption loss is applied to the cluster's frequency- domain channel response for frequency fc + Af within the channel bandwidth W. The oxy- gen loss OLn(fc + Af) for cluster n at frequency fc + Af, where W/2 < W/2 is given as follows: where alf + Af) is the oxygen absorption loss in dB/km at frequency fc + Af. The final frequency-domain channel response is obtained by the summation of frequency-domain channel responses of all clusters. Time-domain channel response is obtained by the reverse transform from the obtained frequency-domain channel response [4,5]. Measurements in mmWave frequency bands have shown that ground reflection in mm Wave has significant effect which can produce a strong propagation path that superimposes with the direct LoS path and induces severe fading effects. When ground reflection is considered, the randomly generated shadow fading is largely replaced by deterministic fluctuations in terms of distance. As a result, the standard deviation of shadow fading, when ground reflec- tion is considered, is set to 1 dB. The value of 1 dB was obtained via simulations in order to maintain a similar level of random channel fluctuations without ground reflection [4,5]. The mmWave channels are sparse, that is, they have few entries in the delay angle bins, although experimental verification of this may be limited due to the resolution of rotating horn antennas used for such measurements. However, a lower bound on the channel sparsity can still be established from existing measurements, and in many environments, the percent- age of delay/angle bins with significant energy is rather low but not necessarily lower than at centimeter-wave frequencies. 300 Chapter 3 Molecular oxygen absorption around 60 GHz is particularly high ( ~ 13 dB/km, depend- ing on the altitude) but decreases rapidly away from the oxygen resonance frequency to below 1 dB/km. While these absorption values are considered high f