# Cost-Benefit Assessment of 5G Rollout: Insights from Brazil
## 2 Technical Enablers and Related Work  
The deployment and cost structure of 5G networks are strongly influenced by a set of enabling technologies that underpin its architecture and scalability. Among these, Massive MIMO (multiple-input multiple-output), small cells, heterogeneous networks (HetNets), and network slicing stand out as critical components. Each contributes to the improvement of spectral efficiency, latency, coverage, and service differentiation. Understanding these technical enablers is essential for techno-economic modeling, as they shape both capital expenditures and operational expenditures, as well as the range of vertical applications and service opportunities that 5G supports. During the first four generations of cellular technologies, up to 4G in 2010, mobile network operators (MNOs) relied on selling subscriptions based on voice and data consumption. However, the surge in mobile data demand and the widespread adoption of unlimited data plans posed challenges to sustaining revenue growth, prompting the exploration of new opportunities through 5G services. Thus, 5G offers MNOs the potential to diversify into areas such as private networks, massive IoT, and ultra-reliable low-latency communications, generating new revenue streams [1]. MNOs are now applying 5G in various sectors, or \"verticals\", including energy, healthcare, manufacturing, agriculture, and transportation. This shift requires sector-specific adaptations in software, hardware, and the spectrum [2]. The success of 5G depends on both technical and economic viability, requiring detailed techno-economic assessments to determine deployment costs and potential value. Although 5G supports three main use cases, namely enhanced mobile broadband (eMBB), massive machine-type communication (mMTC), and ultra-reliable low-latency communication (uRLLC), only eMBB has achieved widespread commercial success so far [3]. eMBB builds on 4G, offering higher data rates and spectral efficiency, making it the first phase of 5G deployment [4]. It utilizes the 5G New Radio (5 GNR) and 4G Evolved Packet Core (EPC), proving its economic viability for MNOs. However, mMTC, mainly related to the Internet of Things (IoT), faces challenges due to market fragmentation, while uRLLC, which is designed for high-reliability and low-latency applications, requires further advancements in 3 GPP standards [5]. The technical design of 5G benefits from various innovations in research and development (R&D). Network capacity can be expanded by increasing cell density, adding spectrum bandwidth, and improving spectral efficiency. Small cells and HetNet increase capacity, while the millimeter-wave spectrum and the 3.5 GHz band expand the available frequencies [6]. Notably, Massive MIMO radio technology represents a significant advancement for spectral efficiency. This technology utilizes multiple antennas on base stations and mobile devices to transmit and receive more data simultaneously [7]. With Massive MIMO, it is possible to precisely manipulate signal beams, directing them to specific users and reducing interference. This not only improves service quality but also increases network capacity, making it one of the most crucial tools in the 5G arsenal to address the growing demand for high-speed data and services [8]. However, 5G is not a single technology but a series of options that allow MNOs to adapt the network to their needs and implementation stage. Among the various possible options, standalone (SA), non-standalone (NSA), and the architectures proposed by the 3 rd Generation Partnership Project (3 GPP) stand out. Each option has technical advantages and disadvantages and a different implementation cost [3]. Considering this, the cost estimation of the electromagnetic spectrum for wireless communication is a multidisciplinary problem that involves a complex interplay of various fields such as engineering, economics, policy and regulation, computer science, business, social sciences, environmental sciences, mathematics, and physics.