Outdoor Macro-Cellular Channel Measurements and Modeling in the 3-18 GHz Band

Fifth generation cellular systems will operate in a wide range of frequencies, covering both the traditional cellular bands, and mm-wave frequency bands, either selecting a specific band or operating in multiple bands simultaneously. For the design of such systems, a detailed understanding of the frequency dependence of the propagation channel is essential. While many channel measurements exist in either microwave bands (below 6 GHz) or mm-wave bands (in excess of 20 GHz), the results are not easily comparable, and furthermore the transition between these bands is not very well known. This paper aims to bridge the gap by providing the results from a channel measurement campaign conducted in an outdoor macro-cellular environment, over the continuous frequency band of 3-18~GHz. We characterize the pathloss, shadow fading, Root-Mean-Square (RMS) delay spreads and coherence bandwidth for line-of- sight (LOS) and non-line-of-sight (NLOS) environments. We also investigate the frequency dependency of the RMS delay spreads and coherence bandwidth. Contrary to expectations, we find generally low dependence of these key channel parameters on frequency.