Radio Propagation Measurements and Cluster-Based Analysis for 5G
Millimeter-Wave Cellular Systems in Dense Urban Environments
Abstract
Empirical channel modeling is necessary for the deployment of the
fifth-generation (5G) millimeter-wave (mmWave) cellular system in actual
environments. In this paper, cluster-based analyses of mmWave channel
characteristics in two typical dense urban environments are performed.
First, radio propagation measurement campaigns are conducted at two
primary 5G bands of 28 GHz and 39 GHz in a central business district and
a dense residential area. The custom-designed channel sounder supports
high-efficiency directional scanning sounding, which helps to collect
sufficient data for statistical channel modeling. Next, using an
improved autoclustering algorithm, multipath clusters and their
scattering sources are identified. Mapping results show that multiple
reflections from exterior walls and diffraction over building corners or
rooftops enhance the coverage for non-line-of-sight (NLoS) links and the
influences of these propagation mechanisms are intuitively embodied as
changes in the topologies of deployment environments. Finally, an
appropriate measure for cluster-level channel characteristics is
provided including cluster number, Ricean K-factor, root mean squared
(RMS) delay spread, RMS angular spread, and their correlations.
Comparisons of these parameters across two mmWave bands are also given.
The measurement and modeling results shed light on a fully understanding
of mmWave channels in dense urban environments across multiple bands.