A delay-centred wideband indoor channel model for MM-wave communications

The frequencies of operation of mm-wave radio networks are the highest of any current radio system, allowing for higher data rates and greater system capacity at the expense of coverage area per base station. Also, the channel has to be carefully modeled, accounting for most propagation mechanisms. Traditionally, rough surface scattering is not taken into account, but the very short wavelength of mm-wave systems demands a more careful approach. The proposed model can be used indoors and within rooms, where coverage from a mm-wave network is not always achieved. Since the path loss for such frequencies is extremely high, the link must be able to overcome shadowing and would often rely on reflected or scattered paths to sustain communication. The simulation model takes rough scattering and specular reflection into account, and comparison with wideband measurements at 5.4 GHz show that the effect of scattering at that frequency is marginal. On the other hand, at the highest frequency of 60 GHz, the wavelength is 5 mm and scattering effects become significant. The model presented here follows a novel approach and was initially developed for infrared communications. The physical characteristics of the room are the input to the channel, but instead of discretising the geometry of the channel, the delay range is calculated before the calculations axe initiated. In this way, the computation is efficient as well as accurate. The delays are modeled sequentially, in order to calculate the power received for every delay bin. The results show that the effect of scattering on the link is important and should not be neglected. The impulse response exhibits negative exponential decaying pulses instead of rapid delta-like waveforms which provides a better agreement with measurements. The following figure illustrates one result of the channel model compared to the measurement of a simple environment at 5.4 GHz.