# Overall Design of Satellite Networks for Internet Services with QoS Support
## 3 Performance Evaluation
### Performance Evaluation for the Delay-Sensitive Service  
In Scenario 2, we evaluated the performance of the delay-sensitive service allowing the long propagation delay in the satellite link according to the traffic load and the burstiness. The RBDC was applied in the resource allocation to eliminate the resource allocation delay. We selected a tight delay constraint that was from 1-4 s as compared to the Scenario 1 using VBDC. Since RBDC is generally applied to the resource allocation of the application such as VoIP and video streaming services, the burstiness was from 1-10, which is less than that of Scenario 1. In this paper, the average data rate was considered in the RBDC of the resource allocation for the efficient resource allocation. Figures 8 and 9 show the throughput and the 95 th percentile end-to-end delay according to the traffic load for the spectral efficiencies of 1 bps/Hz, 2 bps/Hz, and 3 bps/Hz. In Figure 8, the burstiness does not highly affect the throughput. When the traffic load was more than the maximum transmission capacity, throughput values for the spectral efficiencies of 1 bps/Hz, 2 bps/Hz, and 3 bps/Hz converged like the results of Scenario 1. In Figure 9, it is indicated that the 95 th percentile end-to-end delay is a little high. When the spectral efficiency, the burstiness, and the traffic load were 3 bps/Hz, 1, and 5 Mbps, respectively, the value was 1.073 s. In the case of the video streaming service, due to the data transmission of a variable bit rate (VBR), the heavy traffic load that needs many frames for the transmission can be temporarily imposed on UTs regardless of the burstiness, resulting in the increase of the end-to-end delay. For example, the data rate for the intra-frame transmission of the video streaming service was much more than the average data rate of the video service [45; 46]. With similar trends as Scenario 1, the 95 th percentile end-to-end delay increased with increasing the burstiness in this scenario. When the traffic load was more than the maximum transmission capacity, the 95 th percentile end-to-end delay exponentially increased. Figures 10 and 11 show the satisfaction ratio and the  
Figure 8: The network throughput at the application layer according to the traffic load (Mbps) when burstiness varies from 1–10 (RBDC).  
Figure 9: Cont.  
Figure 10: Cont.  
Figure 9: The 95 th percentile delay according to the traffic load (Mbps) when burstiness varies from 1–10 (RBDC).  
Figure 11: The goodput when the spectral efficiency is 3 \(\mathrm{bps/Hz}\) when the traffic load varies from 5–20 Mbps and burstiness varies from 1–10 (RBDC).  
Figure 10: The satisfaction ratio when the spectral efficiency is 3 \(\mathrm{bps/Hz}\) when the traffic load varies from 5–20 Mbps and burstiness varies from 1–10 (RBDC).  
As a result, the factor such as the estimation of effective data transmission rate should be additionally considered in the QoS policy for the delay-sensitive service, allowing the long propagation delay in the satellite network. For example, the RBDC based on average data rate is appropriate for the VoIP service. However, for the video streaming services, its VBR characteristic of the traffic generation and the burstiness of index frames should be considered in the estimation of the effective data transmission rate for RBDC. Thus, the QoS policy should select the suitable scheme to calculate the required resource according to the service.