# Comparative Analysis of 5G Mobile Communication Network Architectures
## 5 Simulation Assumptions and Architecture Robustness Assessment  
### Simulation Assumptions  
Assumptions for the CCC, HCC, and MEC architecture simulations were made for fair comparative analysis. They are listed below.  
**Network structure:** As shown in Figure 4, the network consists of one central cloud facility, connected to six edge clouds in cluster that is in a star shaped topology. For the simulation, it was assumed that the distance between the city where edge clouds are located and the central cloud facility was 200 km for all three architectures. For the radio access network path, it was assumed that the latency for all three architectures are same.  
**Edge cloud connectivity:** For the simulation case study, one of the key simplifying assumption was the implementation of the simplified network policy, which assumes that network will only use dedicated resource allocated to the region. Another assumption made was that each edge cloud interact with central cloud only, not with other edge clouds. Although the standard from ETSI takes into account that edge clouds can connect to nearby edge clouds for mobile application purposes, the case studypresented in this study primarily focuses on computational offloading from edge clouds to the central cloud, which is not related to the task transfer from an edge cloud to another edge cloud, thus justifying the assumption made.  
**Latency in radio access network and core network:** For communication network, latency occurs in radio access network and core network paths. In the simulation, it was assumed that all three architectures had equal amount of latency for both paths for fair comparison. For the radio access network path, the assumed latency for the simulation was set at 3 ms. For the core network path, the amount of latency was set so it corresponds to 200 km distance equivalent latency between the central cloud and edge clouds for all architectures.  
**Measurement units:** For the simulation, the task is defined as a job that a mobile device requests to the cloud, and the workload is defined as the amount of computing resource required to process the task. The cloud computing resource is expressed as the CPU cycle frequency in units of MHz. The workload, which is the amount of CPU cycles required to complete a given task, is expressed in 1000 cycle. The processing time, which is the time required to complete a given task, can be obtained by dividing the task workload by the available computing resource. It is expressed in units of ms. Data traffic, which is the number of tasks generated per time unit, is expressed as tasks per second.  
**Application and key performance index for network architectures:** For the case study, the network was used to transmit data to and from personal mobile communication devices. The performance measure used for this architectural analysis was the percentage of tasks that exceeded end-to-end processing time of 10 ms. This is based on the latency guideline proposed by [PERSON] et al. (2019). The threshold for out-of-specification percentage was set to 5% after consulting Korea Telecom's internal subject matter experts regarding the out-of-specification deviation for this particular application.