A softwarized perspective of the 5G networks Kleber Vieira Cardoso, Cristiano Bonato Both, Lucio´ Rene Prade, Ciro J. A. Macedo, Victor Hugo L. Lopes F Abstract—The main goal of this article is to present the fundamental to clarify that this leap hides the various intermediate steps that theoretical concepts for the tutorial presented in IEEE NetSoft 2020. comprise it. In the telecommunications industry, including for The article explores the use of software in the 5G system composed of advertising reasons, a significant amount of technological devel- the Radio Access Network (RAN) and the core components, following opments and innovations accumulate before defining a generation, the standards defined by 3GPP, particularly the Release 15. The article which was no different at 5G networks. As an example, the Re- provides a brief overview of mobile cellular networks, including basic leases provided by the 3GPP (3rd Generation Partnership Project) concepts, operations, and evolution through the called ‘generations’ of mobile networks. From a software perspective, RAN is presented in the that is one of the leading organizations for standardizing wireless context of 4G and 5G networks, which includes the virtualization and mobile networks. The 4G/LTE networks (Long-Term Evolution) disaggregation concepts. A significant part of the article is dedicated to were introduced in 2008 by Release 8 [5] and, since then, have 5G networks and beyond, focusing on core, i.e., considering the Service- received several updates (represented by new Releases) until the Based Architecture (SBA), due to its relevance and totally softwarized 5G networks were officially introduced by Release 15 [6] in 2018. approach. Finally, the article briefly describes the demonstrations pre- On the other hand, there are technical factors that also support the sented in IEEE NetSoft 2020, providing the link for the repository that definition of each generation. In the 5G system, the radio spectrum has all material employed in the tutorial. usage is expanding to hundreds of MHz or some units of GHz, but it also going to frequency bands of tens of GHz. Moreover, 5G networks consolidate an intense process of softwarization that 1 INTRODUCTION stands out for the adoption of cloud systems and technologies In the generations leading up to the fifth generation of wireless such as virtualization [7], software-defined networks [8], network cellular mobile networks, the supreme effort was made in the slicing [9], and Service-Based Architecture (SBA) [10]. massification of access to customers and increasing the transmis- In addition to the technological aspects, the 5G networks in- sion rates. However, more than just improving bandwidth and troduce changes in the companies’ business model. Traditionally, reducing latency, 5G networks [1] will allow truly disruptive operators of wireless mobile communication systems have focused solutions to emerging in all types of industries [2]. Although many on end-users as the main sources of revenue. In 5G networks, the countries, such as Brazil, are still discussing and preparing for intention is to expand (or even migrate) the focus to have industries the deployment of 5G networks, since 2019, several countries as primary customers [11], [12]. Three main requirements (or (e.g., China, South Korea, and the United States) are already scenarios) have been defined to support this expansion of the implementing, testing, and effectively using the latest generation telecommunications companies’ business model: enhanced mobile of mobile wireless networks. More than 2.4 billion devices are broadband (eMBB), ultra-reliable low-latency communications expected to use 5G networks by 2025 [3]. For now, rates close (URLLC), and massive machine-type communications (mMTC). to (and even higher than) 1 Gbps are still the main novelties, These scenarios are illustrated in Fig. 1(a), which was introduced arXiv:2006.10409v3 [cs.NI] 24 Aug 2020 but several services, mainly based on Internet of Things (IoT), by ITU (International Telecommunication Union) [13], in 2015, as began to be planned and implemented. Autonomous cars, Industry part of the vision of what 5G networks would be. This illustration, 4.0, and virtual/augmented/mixed reality are some of the bets for which presents the leading capabilities of each scenario, is widely relevant applications and tend to serve as interesting use cases for used to try to summarize some relevant properties of 5G networks. new network features. However, as in previous generations, it is In order to meet the requirements of the different scenarios, difficult to predict accurately which applications or services will the concepts of network software began to be adopted, both by be adopted. For the time being, the only consensus is that 5G academia and industry, to make the development of 5G networks networks, when deployed on a significant scale, will represent a (or systems) viable in recent years and also their evolution [9]. new step for wireless communications and will have a deep impact The main reason for the intensive introduction of software in in the society [4]. 5G systems is to extend the flexibility to the mobile network The fifth-generation represents a remarkable technological architecture, supporting different requirements in challenging sce- leap over the fourth generation, introducing significant hardware narios emerging in the digitalized society. Moreover, with the and, above all, considerable software innovations. It is essential network softwarization, it is possible to enjoy of traditional cloud computing, as well as its smaller-scale variants, i.e., fog and Kleber, Ciro, and Victor are with Universidade Federal de Goias´ (UFG), edge. In this context, radio access and core network functions Brazil. Email: fkleber, ciro.macedo, [email protected] Cristiano and Lucio´ are with the University of Vale do Rio dos Sinos are now implemented using the advantages of cloud computing, (UNISINOS), Brazil. Email: fcbboth, [email protected] such as abundant storage, large-scale processing, elasticity, etc. In 2 eMBB later, data-oriented communication devices. Since the first com- Gigabytes in a second, data 3D video, UHD/4K/8K screens mercial mobile cellular network, in 1979, until nowadays, several transfers at extremely high Gigabytes em um segundo, new technologies have been introduced in the communication sys- datatransferências rates de dados a taxa Work Vídeo and play3D, telasin the UHD/4K/8K Cloud de dados extremamente altas tems, but also several concepts remain the same or are very similar. Smart homes/buildings, video Augmented reality camerasDomicílios/prédios inteligentes, In this section, we present relevant concepts of mobile networks in Industrial automation, câmeras de vídeo general and the ones related to cellular networks. Additionally, we Industry 4.0 Voice services Mission-critical applications/ describe the history of the mobile cellular networks very briefly Serviços de voz Smart cities, sensor services, e-Health through the ‘generations’, starting from the first until the fourth, networks, IoT with most of the attention to the fourth generation. The fifth- Autonomous cars generation and beyond have the next section dedicated to them. mMTC URLLC (a) 5G scenarios 2.1 Basic concepts Peak data User perceived The fundamental idea of a cellular network is the use of eMBB High data rate rate relevance multiple low-power transceivers (transmitters+receivers) to offer Average Traffic communication to mobile devices. Actually, the power of these Spectral capacity by Low transceivers is low compared with their predecessors, but it is efficiency area very high compared with mobile devices. Traditionally, these transceivers are mounted in a mast or tower, at an elevated point, Network and have a control unit. This configuration is named as a Base energy Mobility Station or BS, which is responsible for covering an area using a efficiency band of frequencies. Assuming the most traditional positioning in the center of the coverage area, the area’s conceptual representa- Connection mMTC density Latency URLLC tion as a hexagon was the appropriate choice because the distance between the centers of all adjacent areas is the same (equal to (b) Capabilities of the scenarios p 3R). Therefore, a mobile cellular network can be represented Fig. 1. Scenarios (or requirements) defined for 5G networks (left) and as a collection of the neighboring regions, each resembling a capabilities offered in these scenarios (right). cell, as illustrated in Fig. 2(a). In practice, the environmental characteristics and the propagation conditions tend to degenerate the mobile cellular network into something more similar to a addition to enable new services, in the long run, the softwarization Voronoi diagram or tessellation, as illustrated in Fig. 2(b). is expected to reduce the costs of deploying and operating 5G The deployment of the BSs is generally defined by a previ- systems. ous study that takes into consideration factors as topographical The remainder of this article is structured as follows. Sec- characteristics, signal propagation conditions, limitations on siting tion 2 introduces basic concepts related to mobile network cellular antennas, and demand of the users. While in-site measurements networks and the operation of this type of system. This section are common, most of the study is generally performed with presents a brief historic review of the generations until the forth. propagation models that can estimate the signal power