the cell edges experience better quality than in macro cellular environments in the same scenario. The small cells deployments can be used by nomadic users (low-mobility users) or stationary devices (e.g. things connected via the mobile network), while the coverage of high mobility users is provided by macro cellular coverage (e.g. with cells ranging from several kilometers in radius in urban areas to 20-30 km in rural areas). Another important aspect in the 5G mobile networks is their target to massive IoT, such as support for at least 1 million devices per km². IoT devices require ultra- broadband speeds, but only tens or hundreds of kbit/s, referred to as NB access. Hence, such NB access is standardized in 5G architectures in parallel with the gigaspeed access. With the massive IoT, the 5G mobile networks' target is to enter different verticals, such as intelligent transportation service (e.g. vehicle-to-X communication), automation of the industry, etc., which adds the demand for delay-critical services that are going to be provided via the 5G mobile network. Such critical service (e.g. direct automation, intelligent public transport) has strict QoS requirements regarding guaranteed bitrates, end-to-end delay (which has to be very low, lower than voice delay), and delay variation requirements (i.e. jitter requirements). So, the 5G mobile architectures in general have three main targets: to provide in par- allel ultra-broadband speeds for Internet access and legacy telecommunication services (e.g. voice, video), massive IoT support (to expand the IoT services on a global scale, in a standardized manner), and support for new critical services (over the 5G mobile network), which have very strict QoS requirements. The 5G network architecture consists of two main parts (Figure 5.5): the CN and RAN domains. The 5G mobile network also allows placement of network functions in radio network sites such as access and aggregation sites. 5G RAN, called NG-RAN (next generation radio access network), uses New Radio. The 5G 