Polarimetric Diffuse Scattering Channel Measurements at 26 GHz and 60 GHz

Fifth generation (5G) networks will utilise the large bandwidth available in millimetre wave (mmWave) frequency bands up to 100 GHz in order to meet the ever-increasing high data rate demands. Efficient communications system design for such networks requires a thorough understanding of the propagation properties of the electromagnetic signals at such high frequencies. This paper presents the results of a polarimetric channel measurement campaign at 26 GHz and 60 GHz showing that diffuse scattering can be a dominant propagation mechanism for mmWave links. The use of a wide bandwidth provides a detailed insight into the multipath structure of the channel. It is shown that in a diffuse scattering scenario, nearly co-incident signals create small scale fading that affects the flatness of the channel significantly even when directional antennas are used. This also results in large co-to-cross polarisation ratio (XPR) variations across the channel bandwidth.