# Unleashing the Potential of 5G for Smart Cities: A Focus on Real-Time Digital Twin Integration
## 2 Current Trends for 5G in Smart Cities
### Existing Applications of 5G in Smart Cities
The network consists of 20 IoT sensor nodes randomly distributed across a \(50\times 50\) unit area, representing the spatial unpredictability of sensor deployment in real-world smart cities. Connections between nodes are established based on a distance threshold, where any two nodes within 15 units are considered to be directly connected, simulating the reliable range of 5G communication. This threshold ensures that the network captures the benefits of 5G's ultra-reliable and low-latency capabilities, particularly in densely packed urban zones. The underlying network structure is visualized as an undirected graph using an adjacency matrix, which monitors all pairwise connections and underpins the visual layout of the sensor web. The heatmap overlay is based on node positions, reflecting variations in the environmental data intensity, such as pollution levels or temperature gradients, thereby transforming static spatial data into an interpretable dynamic metric. This visualization not only illustrates the physical arrangement and communication paths of the network but also underlines the system's potential for supporting real-time, location-aware environmental analytics, which are essential for smart city decision-making. Previously, environmental monitoring systems in smart cities faced the challenge of processing large volumes of data from a variety of sources, leading to delays in reporting and decision-making. Traditional networks were often unable to support the fast-paced, real-time demands of environmental monitoring, especially in densely populated areas, where data traffic is particularly heavy. 5G's ability to control this surge in data traffic without delays ensures that environmental conditions can be monitored in real time, allowing cities to respond faster to pollution spikes, traffic congestion, and other urban challenges [33; 37; 38]. This provides city officials with the tools they need to manage resources more effectively and to respond to environmental concerns more swiftly. Within the field of smart transportation, 5G is also used to facilitate the development and implementation of self-driving vehicles and advanced traffic control systems [40; 41; 42]. The ultra-reliable low-latency communication (URLLC) aspect of 5G ensures that self-driving vehicles can share critical information with other vehicles, infrastructure, and control centers instantly via a reliable communication network [43; 44]. This communication is needed for enhancing safety and improving traffic movement in crowded regions [40; 41]. Intelligent traffic systems powered by 5G analyze traffic patterns and dynamically adjust  
Figure 3: Real-time environmental monitoring metrics with 5G [33; 37; 38; 39]. signals to alleviate congestion and increase efficiency [40; 41; 42]. Cities such as Cape Town, eThekwini, Tshwane, and Johannesburg in South Africa are also exploring these technologies and the potential of 5G to transform urban living [45; 46]. These smart cities make use of digital technologies to enhance efficiency, optimize resource usage, and reduce emissions, aligning with global sustainability goals. Before the advent of 5G, smart transportation systems encountered difficulties in handling the vast quantities of data produced by connected vehicles, traffic signals, and road infrastructure [40; 41; 42]. With their limited bandwidth and higher latency, earlier networks struggled to facilitate instant communication between these systems, leading to slower response times and less accurate traffic predictions [43; 44]. The introduction of 5G addresses these limitations by enabling real-time data exchange between self-driving vehicles, traffic management systems, and infrastructure [42; 43; 44]. This capability enhances the safety and efficiency of transportation networks, contributing to smoother traffic flow, reduced congestion, and safer roads. Figure 4 demonstrates the significant effect of 5G technology in improving traffic management efficiency at urban intersections of smart cities [40; 42; 43].