# Comparative Analysis of 5G Mobile Communication Network Architectures
## 1 Introduction  
With the emergence of the smartphone, the amount of data traffic has been growing exponentially since 2008. Based on user demand and the introduction of new technologies, mobile communication technology is currently evolving from fourth generation (4G) to fifth generation (5G). The 5G mobile communication technology (5G herein) can be characterized by three major features: enhanced Mobile Broadband (eMBB), massive Machine Type Communication (mMTC), and Ultra Reliable Low Latency Communication (URLLC). The main concept of the eMBB is to extend frequency resources to a millimeter Wave (mmWave) above 6 GHz. mMTC is defined as a network capacity to simultaneously accommodate millions of devices in an area of 1 km\({}^{2}\). Finally, URLLC is a feature for guaranteeing end-to-end latency within 10 ms. Among the main features of 5G, URLLC can be recognized as the most distinguished feature that differentiates 5G from previous generations of mobile communication technologies. Prior to the discussion of the URLLC, the mobile network architecture needs to be defined. A mobile network can be sub-divided into radio access network and core network. The radio access network is the network link assigned on radio frequency resources and the core network is the network link assigned to wire-line resources. For 5G standard, significant efforts have been made to reduce the latency of radio access networks, including the use of mini-slots and shortened Transmission Time Interval [1; 2; 3; 4; 5]. However, reducing the core network latency is more difficult because of the physical distance limitation (-200 km/ms). To address the challenges in reducing core network latency, a new network architecture called Multi-access Edge Computing (MEC) architecture has been proposed [6; 7; 8]. The main concept of MEC is to reduce the physical distance between user entity (UE) and application server. Network functions are virtualized on clouds, in which application servers are collocated; MEC is an architecture that allocates computing resources closer to UE. Figure 1 shows the current 4G architecture and the new MEC architecture. The 4G architecture shown in this paper will be referred to as the Centralized Cloud Computing (CCC) architecture [9; 10], as tasks are processed at the central cloud. In the CCC architecture, the application server is located at the central cloud, causing a delay in the core network if the physical distance between the central cloud and the UE is long. The MEC architecture can reduce transmission delay by placing application server and computing resource (edge cloud) near the target region. However, a network based on the MEC architecture can experience significant delay under certain disruptive situations. Figure 2 shows two of these situations and illustrates the different responses of the CCC and MEC architectures. The left side of the figure shows both the CCC and MEC-based networks operating under normal data traffic conditions. All the data traffic in the CCC-based network is transmitted to the central application server, where the central cloud is located. In the MEC-based network, the regional data  
Figure 1: Centralized Cloud Computing (CCC) and Multi-access Edge Computing (MEC) architectures. Figure 2: CCC and MEC architecture responses to different data traffic situations. traffic is transmitted to respective regional application server to be processed at the edge cloud. The right side of the figure depicts a situation where a data traffic spike occurs in a particular region. Events where large crowds gather, such as the New Year's Eve celebration in Times Square, can cause unusually high data traffic in a specific region. In the current CCC-based network, no noticeable delay occurs as the data traffic is handled by the central cloud, which has sufficient computing resources. However, the MEC-based network has a high probability of experiencing significant delay in that specific region.