# Adaptive Emergency Call Service for Disaster Management
## 5 Simulation Results
### Performance Analysis
#### 5.2.4 Impact of Emergency Data Size  
The emergency data size depends on the type of data such as text, audio, video. The emergency data size increases respectively with text, audio, and video data types. Moreover, the emergency call data size is completely correlated with the transmission duration of the emergency call (D2D or classic mode). Hence, the impact of emergency data size on the performance of 5G-SOS is observed in Figures 12 and 13, where emergency calls occur within a fixed ETI. As shown in Section 5.2.4, when the data quality is low, the success rate is higher compared to transferring high quality data. Hence, it is noted that the proposed 5G-SOS is mostly suitable for a low quality data transfer, which would be convenient during disaster situations. As the duration for emergency call transfer increases, the number of busy nodes, processing other emergency calls, increases. This leads to a lower relaying efficiency and thus a drop in the overall number of successful transmissions. As expected, the latency increases in 5G-SOS. M-HELP and FINDER increase the data transfer time since the data type directly impacts the delay at each relay. Further, only one emergency request could be transmitted at a time which correspond to the delay before relaying. Figure 11: Comparison of end–end latency against NoU under 5G-SOS, M-HELP, and FINDER. Parameters: NoU: 6000 to 15,000, NEC: 5000, ETI: 1800 s (30 min). Figure 12: Comparison of successful rate against emergency call transfer duration under 5G-SOS, M-HELP, and FINDER. Parameters: NoU: 15,000, NEC: 5000, ETI: 1800 s (30 min). 2.5 Impact of the Percentage of the Number of Emergency Calls (NEC) over the Total Number of UEs (NoU)  
First, it is observed, in Figure 14, that the success rate of 5G-SOS is nearly 100% when the number of emergency calls are less than 5% of the total devices. Further, when the percentage of NEC over NoU approaches 80%, i.e., almost all nodes generate an emergency call, around 37.4% of calls are relayed successfully against only 29.5% in M-HELP and 8.7% in FINDER. Moreover, when 5000 emergency calls occur within an ETI of 600 s (10 min), more than 50% of calls reache the core network, as observed in Figure 8.  
Figure 15 presents the _EEL_ under varying NEC over NoU ratios. It is noted that 5G-SOS adapts the \(T_{\text{max}}\) parameter according to the \(n_{k}\) and \(n_{c}\) factors, as discussed in Section 4. Hence, when the ratio between the number NEC and NoU reaches 80%, the _EEL_ is further reduced by adapting parameters such as \(T_{\text{max}}\), \(RS_{\text{th}}\), to serve large amounts of emergency calls. Overall, we observe that the 5G-SOS protocol presents a reduced latency over M-HELP and FINDER. Figure 14: Comparison of the success rate against the ratio of the number of emergency calls (NEC) to the number of UEs (NoU) under 5G-SOS, M-HELP, and FINDER. Parameters: NoU: NEC: 1% of NoU to 80% of NoU, NoU: 15,000 UEs, ETI: 1800 s (30 min). Figure 13: Comparison of end–end latency against emergency call transfer duration under 5G-SOS, M-HELP, and FINDER. Parameters: NoU: 15,000, NEC: 5000, ETI: 1800 s (30 min). Additionally, as seen in Figure 16, 5G-SOS provides a slightly higher average number of messages per node than M-HELP. The amount of emergency call requests served by 5G-SOS is higher than M-HELP due to buffering multiple calls. Hence, the average number of messages per node has increased against M-HELP. Furthermore, compared to FINDER, 5G-SOS and M-HELP adopt a massively distributed approach where there is no weight on a particular device to relay the emergency call to the gNB. Since the relay devices listen to the transmissions of the same emergency data before transmitting the emergency data on their own, less traffic is generated in the network. Furthermore, the stronger relay devices transfer the message before any other relay device in the neighborhood.