# 5G New Radio Open Radio Access Network Implementation in Brazil: Review and Cost Assessment
## 2 Background  
### 5G NR (New Radio) Technology  
The emergence of 5G New Radio technology has revolutionized wireless communication, offering faster speeds, greater capacity, and improved reliability. This advancement opens opportunities for innovative applications and services to improve mobile broadband, ultra-reliable low-latency communications, and massive machine-type communications [7]. Furthermore, 5G supports new types of applications with diverse requirements, enabling the Internet of Things (IoT) to be widely used in smart city applications, sensors, and actuators, using machine-to-machine (M2M) communication, which was impossible with 4G technology.  
Previous generations of wireless mobile networks (1G, 2G, and 3G) focused on voice over a dedicated circuit network. With 4G, the network transitioned to packet-switching, facilitating data packet exchange. In turn, 5G NR improves on 4G networks, increasing speed and reliability and reducing latency. This low latency is essential for new critical solutions and meeting strict feasibility requirements. In 5G NR, the Quality of Experience (QoE) is enhanced by adding new users to the MNO without compromising service quality. Therefore, 5G technology is expected to revolutionize industries such as healthcare, transportation, and manufacturing [8].  
In order to meet the diverse requirements of emerging use cases, 5G utilizes a flexible and reconfigurable architecture that efficiently integrates various radio and core network technologies [9; 10]. A key feature of 5G NR is its flexible frame structure and scalable numerology, enabling optimized support for various use cases, from high-speed mobile broadband to ultra-reliable low-latency communications [11].  
The technology supports various carrier frequencies, from sub-6 GHz to mm-wave bands, allowing for high data rates and increased network capacity [12]. In addition, 5 GNR includes improvements in beamforming, massive MIMO (Multiple Input-Multiple Output), and non-orthogonal multiple access techniques to boost spectral efficiency and throughput. It also enables spatial multiplexing and interference suppression, enhancing network performance [13].  
Implementing 5G NR introduces new challenges, especially in network security. The variety of services, applications, and connected devices in 5G networks increases cyber threats, which pose security and privacy risks [14]. Furthermore, as networks become more software-defined and virtualized, security frameworks and protocols are essential to protect the integrity and confidentiality of 5G communications [15].  
Energy efficiency is crucial in 5G NR. Developing energy-efficient solutions, optimizing power consumption, and ensuring sustainability and environmental impact is important [8; 9; 10; 11]. The adoption of 5G NR is expected to support new applications such as autonomous vehicles, smart cities, and critical communication systems with low latency and high reliability. In healthcare, 5G NR could enable remote surgeries and continuous patient monitoring [16]. The rollout of 5G NR encounters obstacles such as high infrastructure costs, extensive network deployments, and stakeholder coordination. Managing the heterogeneous nature of 5G networks with various technologies presents network management and automation challenges.  
Researchers are exploring technologies beyond 5G, including terahertz communications, AI-driven network optimization, and intelligent reflecting surfaces to improve wireless systems [17].  
Overall, 5G NR technology is a major advancement in wireless communication, providing unprecedented data rates, latency, and connection density capabilities. In Latin America, implementation of this technology faces challenges due to the diverse geographic and socioeconomic landscape of the region, which requires innovative solutions to meet its specific requirements.