Comparisons of Channel Parameters and Models for Urban Microcells at 2 GHz and 5 GHz [Wireless Corner]

The goal of this paper was to find the differences of the channel models and parameters as well as the correlations of the channel parameters between 2 GHz and 5 GHz with 100 MHz bandwidth when measurements were performed in exactly the same routes for urban microcells. The path-loss models and shadow fading were studied by using single-input single-output (SISO) measurements. The channel characteristics were investigated by the rms delay spread, rms angular spread, shadow fading, Ricean factor, number of clusters, cross-polar discrimination, and channel capacities using both SISO and MIMO (multiple-input multiple-output) measurements. Static measurements at 5 GHz were also performed in both micro- and macro-cells to investigate clustering effects. Moreover, the channel models and parameters were compared with WINNER work to test their validity in urban microcells. The main conclusion was that the 2 GHz and 5 GHz frequencies can have different propagation behaviors causing the independent channel parameters. However, it was found that their coherence bandwidths were highly correlated. The WINNER path-loss models over-estimate the path losses, both in the line-of-sight (LOS) and non-line-of-sight (NLOS) street canyons where strong guided waves exist. Irrespective of carrier frequencies, the channel parameters offered by WINNER may roughly estimate the channel by implementing its generic model.