## 4 IEC's Challenges
In addition, many new challenges must be studied in order to create an advanced ecosystem where all players in the network (i.e., IoT users, service/infrastructure providers, and mobile operators) can benefit from advanced services. These challenges are summarized as follows [18]. _Distributed Resource Management:_ Resource allocation is an important challenge to the success of IEC due to limited resources, the increasing number of applications, and the massive increase in mobile traffic [55; 56]. Multi-purpose resource allocation optimization is different in different situations due to the diverse nature of applications, heterogeneous IEC servers, different user requirements/characteristics, and channel connectivity characteristics. With a large number of users, the wireless channel will be in trouble and competition among users for scarce computing resources will become extremely intense [57]. Although the centralized approach can deliver competitive performance, it suffers from low computational complexity and huge reporting expenses. Therefore, the central approach is not suitable for distributed IEC systems [12; 58]. Additionally, there may not be a dedicated backhaul for information exchange and account offloading, and even if there is, the wireless connection can be congested due to the high burden of sharing large data [59]. _Reliability and portability:_ Condensation is the cornerstone of the 5G network and is expected to reap enormous benefits. However, how to manage mobility and ensure reliability is a huge challenge in these environments. First, with several smaller servers covered, user mobility can cause frequent deliveries, resulting in service downtime issues and affecting overall network performance [60]. After that, users (such as vehicles) may move to new locations during the account of the period. In such a case, users may not be able to receive the mathematical result because they have already exited the service coverage for their servers. Therefore, efficient computation dump forms are essential for application completion. Moreover, the dynamic change in the number of offloading users leads to random uplink interference and variable computing resources over time [61]. Finally, providing reliable IEC services in mobile environments is really challenging due to the time-varying dynamics of wireless communication and user mobility. _Network integration and application portability:_ IEC servers can be deployed in various locations within the RAN based on specific technologies, and technical and business requirements. Thus, another important challenge is the seamless integration of IEC into the existing backbone network architecture and interfaces [48]. The presence of the IEC and the enabled applications should not affect the basic network and peripheral hardware standards. According to [38], a key component of IEC integration is the ability of IEC to interact with 5G networks in directing traffic and receiving relevant control information. Moreover, the application migration entails what are called applicability requirements. This eliminates the need for application developers to design multiple versions of different IEC systems. _Coexistence of IEC and Cloud Central:_ Cloud Distributed centers, with abundant computing resources, can handle big data applications at near-zero time and support a large number of users. However, distributed IEC is highly desirable because the computation at the edge of the network cannot only satisfy user requirements but also reduce end-to-end delays caused by traffic congestion and transmission delay. In comparison to the HetNet architecture, it is very beneficial to implement IEC in a hierarchical manner, i.e., user layers, terminal computing and cloud computing [62]. In this way, the IEC vendor also injects computing resources into small eNBs so that the advantages of HetNets can be exploited to diversify wireless transmission and spread the computing requirements [50; 63].