# Leveraging Blockchain Technology for Secure 5G Offloading Processes +
## 1 Introduction  
5G has recently enabled the concept of smart cities to become a reality, facilitating the creation and implementation of innovative applications. Before the advent of 5G, smart cities were already under development, using existing 3G and 4G technologies which, while offering limited speeds and capabilities compared to 5G, already enabled the deployment of basic IoT applications and limited connected services [1]. However, these networks could not match the high speed, data capacity, and low latency offered by 5G. This limits the ability of smart cities to handle large volumes of data generated by IoT devices and advanced applications such as augmented and virtual reality or advanced traffic and energy management, or to provide real-time responses as demanded by critical applications such as autonomous vehicles or public safety systems. In addition, pre-5G networks had limited capacity to connect many devices simultaneously. This was a challenge in smart cities, where millions of IoT devices are expected to be connected and operating efficiently [2, 3]. In this context, 5G technology has transformed smart cities by enabling a wide range of innovative applications and services [4, 5]. It has already played a crucial role in transforming urban environments, making them more efficient, sustainable, and liveable [6]. First, ofall, 5G facilitates the deployment of massive numbers of IoT sensors and devices throughout cities. This dense network of connected devices allows the collection of real-time data on various aspects of city operations, including traffic patterns, air quality, energy usage, waste management, and public safety, resulting in more efficient public services which reduce waiting times and improve overall satisfaction. The ability to gather and analyze this wealth of real-time information provides city planners and managers with unprecedented insights to optimize services and operations. Secondly, 5G IoT enables cities to implement more intelligent and responsive infrastructure systems. Smart traffic management systems can use real-time monitoring and AI-powered traffic light optimization to reduce congestion and travel times. Smart grids benefit from more efficient energy distribution and integration of renewable energy sources. Smart water systems can now detect leaks and optimize water distribution, while smart waste management systems use IoT sensors to monitor waste levels and optimize collection routes. These advanced infrastructure systems improve efficiency, reduce costs, and enhance sustainability in urban areas. Third, the low latency and high bandwidth of 5G enable more effective public safety applications. For example, high-definition video surveillance with AI-powered analytics can enhance threat detection capabilities while real-time communication and coordination between emergency responders could improve response times and effectiveness. In addition, 5G enables the faster deployment of drones and robots for search and rescue operations. These capabilities allow cities to respond more quickly and effectively to emergencies and security threats. Finally, regarding autonomous and connected vehicles, 5G-based vehicular communications improve traffic flow and safety, as well as driving experience based on optimized real-time navigation updates and routes, making commuting more efficient and convenient. These advancements lead to safer roads, reduced congestion, and more efficient urban mobility. In summary, 5G helps cities become smarter in terms of safety, functionality, sustainability, and economy. However, although 5G technology has begun to revolutionize connectivity in smart cities, its deployment is already facing several challenges, especially in terms of quality coverage [7; 8; 9]. * Limited infrastructure: The 5G network requires a dense infrastructure of base stations and antennas to provide adequate coverage within cities. However, existing infrastructure today is not enough for the large number of current and future services.