## 2 Edge Computing
### Edge Computing Challenges  
EC is characterized by higher bandwidth, lower latency, and real-time services, but it is still in the development stages and lacks a well-defined standard framework. As illustrated in Figure 4, the number of edge devices is experiencing rapid growth, creating significant challenges for cloud servers in handling real-time data processing. Statista projects that by 2030, there will be approximately 6.5 billion consumer-focused edge devices, with their average processing speeds advancing exponentially. As a distributed computing technology, EC necessitates well-defined deployment strategies for application workloads on edge nodes. Deployment strategies should be able to answer key questions like where to place a workload, connection policies, and heterogeneity of nodes [94]. EC-driven IoT services create management challenges that organizations should overcome to ensure resilient and reliable operations. Equipment suppliers, service providers, and software vendors are required to work collaboratively to offer cohesive interoperability between various network functions and seamless integration from across edge-to-cloud infrastructure. These factors present challenges in deploying, scaling up, and managing the EC paradigm [95]. Figure 4: Projected edge devices growth. Figure 3: Edge computing architecture. Some of the challenges that must be addressed for the widespread adoption of edge computing are discussed below. * _Heterogeneity._ Many hardware devices and communication standards of diverse natures are deployed at edge networks [96]. EC exhibits heterogeneity across multiple dimensions, including hardware architecture, operating systems, programming languages, accessibility, and the nature of tasks [97]. First, edge devices are diverse, generating data in various formats. Second, data are transmitted through various network access technologies, including 3G, 4G, 5G, WiFi, WiMAX, and LPWAN technologies like Sigfox [98]. Third, the heterogeneous edge nodes providing services encompass a variety of devices such as end-user devices, access points, routers, and switches [49; 91]. * _Coordination between communication and computing._ The integration of EC into IoT systems adds significant complexity due to the diverse resource constraints and operational requirements of edge servers and IoT devices [96]. Mobile edge computing (MEC) is a computing model that extends cloud computing to the network's edge [99]. Researchers are exploring the integration of Low Earth Orbit (LEO) satellites with MEC's for low-latency computing offloading services by placing MEC servers on LEO satellites [100] as well as collaborative MECs among connected entities [101]. Network slicing divides a single physical network into multiple virtualized, independent, and tailored networks, aligning with the distributed models of EC. It is managed through the combined optimization of computing and communication resources in EC environments [102]. * _Partitioning and Offloading Tasks._ The computational tasks are divided into smaller sub-tasks, and these tasks are processed either locally on the edge device or offloaded to more powerful edge servers or the cloud. The overall system performance is enhanced by partitioning and offloading tasks while optimally balancing computing and communication resources [103]. Task offloading is a comprehensive process involving application partitioning, decision-making regarding offloading, and executing tasks scattered across the system [104]. The main challenges in designing partitioning and offloading algorithms involve determining the optimal granularity for partitioning, managing resource limitations, adapting to dynamic environments, and addressing the complexity of offloading within blockchain-enabled communication systems [103]. In an MEC system with multiple edge nodes (ENs) serving multiple users, user association is pivotal in shaping the task partitioning strategy, necessitating the joint optimization of task partitioning and user association [105].