# A Channel Allocation Mechanism for Cellular Networks
## 5 Simulation Analyses
### Simulation Results and Analyses
#### 5.2.3 Comparisons between SCA and Proposed Mechanism  
In this subsection, this study analyzed the CBPs that are derived from the traditional SCA mechanism and the proposed mechanism under the two cases. The CBP (\(P_{i}\)) is denoted as the number of the call blocks (\(B_{i}\)) divided by the number of handover In (\(I_{i}\)) in Cell\({}_{i}\). The traditional SCA mechanism doesn't consider the specific channel propagation conditions. [PERSON] and [PERSON] define the parameter \(D\) and \(R\)[10], where \(D\) is the physical distance between the two cell centers equal to 1 km and the \(R\) is the radius of the cell equal to 0.5 km in this case. They only assumed that the distance (\(D/R\)) which depends on the cellular system environment is allowed to reuse the same channel in cells. Therefore, if the channel is allocated to Cell\({}_{i,}\), it cannot be reused in the same cell at the same time because of unacceptable co-channel interference. In SCA, the number of channels for handover events that are calculated by Formula (12) is equal to 2. Otherwise, in the proposed mechanism, the number of channels for Handover In in each cell is dynamically adjusted according to the traffic information in each cell. The comparison between SCA mechanism and the proposed mechanism is introduced as follows:  
\[N=\frac{1}{3}\sigma^{2},\text{ where }\sigma=\frac{D}{R} \tag{12}\]  
In Case 1, this study analyzed the numbers of Handover In (\(I_{i}\)) during peak hour and off-peak hour. Figure 22 shows that the minimum amount of traffic flow and the minimum number of Handover  
Figure 21: The number of Handover Out (\(O_{6}\)) in Cell\({}_{6}\). Figure 20: The traffic flow in Cell\({}_{6}\). In (\(I_{6}\)) in Cell\({}_{6}\) are during 4:00 a.m. (i.e., off-peak hour). Otherwise, the maximum number of the traffic flow and the maximum number of Handover In (\(I_{6}\)) in Cell\({}_{6}\) are during 8:00 a.m. (i.e., peak hour). Figure 23 shows that the CBPs (\(P_{6}\)) are derived by using SCA and the proposed mechanism in Cell\({}_{6}\) during simulation time 4:00 a.m. and 8:00 a.m.. For Handover In events, the number of channels in the traditional SCA mechanism is set to 2 and the number of channels in the proposed mechanism is dynamically adjusted depending on the actual traffic information. Through Figure 23, this study can discover that the all CBPs in this case are less than 21.5% by using the proposed mechanism, which is better than using the SCA mechanism. The results indicate that the proposed mechanism is suitable for the normal case in real life. In Case 2, the traffic accident occurs at the mileage point from 5.05 to 5.35 km between the simulation time 15 th and 45 th min. This study analyzed the relation of the traffic information and the number of Handover In (\(I_{6}\)) in Cell\({}_{6}\) before and after the traffic accident occurrence. Through Figures 20 and 21, this study can discover that the amount of traffic flow and the number of Handover In (\(I_{6}\)) in Cell\({}_{6}\) decrease rapidly when traffic accidents occur. Moreover, the number of Handover In (\(I_{6}\)) in Cell\({}_{6}\)  
Figure 23: The CBPs (\(P_{6}\)) are derived by SCA and the proposed mechanism during 4:00 a.m. and 8:00 a.m. in Cell\({}_{6}\). Figure 22: The number of Handover In (\(I_{6}\)) at 4:00 a.m. and 8:00 a.m. in Cell\({}_{6}\). dramatically increases when accidents are removed. Depending on the variation of traffic information, this study can expect that the number of Handover In (\(I_{i}\)) increases dramatically with the amount of traffic flow increase. Therefore, if the cellular system adopts the traditional SCA mechanism, it can't afford the substantial increase of the number of channels for handover events, and it will cause the higher CBP. Figure 24 shows that the CBPs are derived by using the SCA mechanism and the proposed mechanism.