Spatial Propagation Characteristics of 28 GHz Frequency Band in UMi Scenario

This paper presents the wideband channel characteristics of 28 GHz in urban microcell (UMi) scenario based the measurement in Beijing. Both the omnidirectional-antenna-based measurement and the horn-antenna-based measurement are performed with bandwidth up to 800 MHz. The standard deviation of shadow fading ($\sigma_{SF}$) is studied and is compared with that value in standard protocol. Unlike traditional method, the $\sigma_{SF}$ is calculated with data captured in each single route in this paper. It is found that in a specific environment, the standard model obtained by traditional method overestimate the $\sigma_{SF}$ of this frequency band to a large extent both in line of sight (LOS) environment and non line of sight (NLOS) environment. In addition, the 3-Dimensional angle information is estimated with the space alternating generalized expectation-maximization (SAGE) algorithm. The angle spread of arrival (ASA) and the angle spread of departure (ASD) are investigated and the cluster characteristics at different rotation measurement sites are analysed. It is found that dimension of parameter space that used in clustering algorithm has a great impact on the clustering result of the recognizable multipaths.