tx antennas at the transmitter and Nrx antennas at the receiver. The small-scale parameters such as delay Tn,m, azimuth AoA Test environment reflects geographic environment and usage scenario which is used for the evaluation pro- cess; however, it has a direct relevance to the deployment scenario. The test environments defined in 3GPP and ITU-R are as follows: Indoor hotspot-eMBB is an indoor isolated environment at offices and/or in shopping malls based on stationary and pedestrian users with very high user density. Dense-urban-eMBB is an urban environment with high user density and traffic loads focusing on pedes- trian and vehicular users. Rural-eMBB is a rural environment with larger and continuous wide area coverage, supporting pedes- trian, vehicular, and high speed vehicular users. Urban macro-mMTC is an urban macro-environment targeting continuous coverage focusing on a high number of connected machine type devices. Urban macro-URLLC is an urban macro-environment targeting ultra-reliable and low-latency communications. 308 Chapter 3 Paths Elevation Cluster rx,n.m Azimuth tx,n,m Cluster n rx,n,m Ray m Fix,nov, ) Transmitter antenna pattern Frx,nm,9 ( ) Receiver antenna pattern ZoD offset LoS ZoD ZoD mean Diffraction Penetration Outdoor LoS UEs Outdoor/indoor NLoS UEs Refraction Reflection Figure 3.8 Illustration of 3D MIMO channel model and its parameters [4]. New Radio Access Physical Layer Aspects (Part 1) 309 Orx,n,m' elevation AoA Orx,n,m, azimuth AoD Qtx,n,m and elevation AoD Otx,n,m are assumed to be different for each ray. In the primary module of 3GPP 3D channel model, the number of clusters are fixed and frequency independent. The typical number of clusters reported in the literature is often small, random, and can be modeled as a Poisson distribution. By choosing an appropriate mean value of the Poisson distribution, the events with a larger number of clusters with a low probability may also be produced. The 3GPP 3D channel model is a geometric stochastic model, describing the scattering environ-