# Evaluation of VoIP QoS Performance in Wireless Mesh Networks
## 4 Results and Analysis
### Analysis Summary  
In order to analyze how the nodes performed in terms of the VoIP quality considering the MOS values, delay, jitter, and packet loss in all scenarios, we have compared all scenarios' performance for VoIP initiators and receivers based on each scenario's results, as shown in Figure 15a for VoIP initiators and Figure 16b for receivers. Figure 14: Platoon MOS values for VoIP initiators and receivers: (**a**) VoIP initiators; (**b**) VoIP receivers. Figure 15: All scenarios’ MOS values comparison for: (**a**) VoIP initiators; (**b**) VoIP receivers. The analysis shows that the following scenarios with the mentioned choice of IEEE 802.11 standard(s), voice codec and routing protocol are the best performing ones for VoIP initiators based on the analysis of the MOS values (Figure 15), end-to-end delay (Figure 16), jitter (Figure 17), and packet loss (Figure 18):  
* PL4 = Platoon, waypoint mobility, 802.11g, G.729 codec, AODV
* FV2 = Flooded village, no mobility, 802.11g, 802.11, G.711, AODV
* PL2 = Platoon, waypoint mobility, 802.11g, 802.11, G.711, AODV
* FV4 = Flooded village, no mobility, 802.11g, 802.11, G.729, AODV
* FV3 = Flooded village, no mobility, 802.11g, 802.11s, G.729, HWMP  
For VoIP receivers, the following scenarios show the best VoIP performance:  
* FR2 = First responders, waypoint mobility, 802.11g, 802.11, G.711, AODV
* FV4 = Flooded village, no mobility, 802.11g, 802.11, G.729, AODV
* FR4 = First responders, waypoint mobility, 802.11g, 802.11, G.729, AODV
* FRW4 = First responders, random waypoint mobility, 802.11g, 802.11, G.729, AODV
* PL4 = Platoon, waypoint mobility, 802.11g,, 802.11, G.729 codec, AODV  
The analysis also shows that the following scenarios with the mentioned choice of IEEE 802.11 standard(s), voice codec and routing protocol result in the worst VoIP performance for VoIP initiators:  
* IV5 = Isolated village, no mobility, 802.11n, G.711 codec, AODV
* IV6 = Isolated village, no mobility, 802.11n, G.729 codec, AODV
* IV1 = Isolated village, no mobility, 802.11g, 802.11s, G.711 codec, HWMP
* IV2 = Isolated village, no mobility, 802.11g, 802.11, G.729 codec, AODV
* PL6 = Platoon, waypoint mobility, 802.11n, G.729 codec, AODV  
For VoIP receivers, the following scenarios show the worst VoIP performance:  
* IV6 = Isolated village, no mobility, 802.11n, G.729 codec, AODV
* IV5 = Isolated village, no mobility, 802.11n, G.711 codec, AODV
* PL3 = Platoon, waypoint mobility, 802.11g, 802.11s, G.729 codec, HWMP
* IV1 = Isolated village, no mobility, 802.11g, 802.11s, G.711 codec, HWMP
* FR3 = First responders, waypoint mobility, 802.11g, 802.11s, G.729, HWMP
* FV3 = Flooded village, no mobility, 802.11g, 802.11s, G.729, HWMP
* IV2 = Isolated village, no mobility, 802.11g, 802.11, G.729 codec, AODV
* PL6 = Platoon, waypoint mobility, 802.11n, G.729 codec, AODV
* PL1 = Platoon, waypoint mobility, 802.11n, G.729 codec, AODV
* PL1 = Platoon, waypoint mobility, 802.11g, 802.11s, G.711 codec, HWMP
* FV5 = Flooded village, no mobility, 802.11n, G.711 codec, AODV  
Considering the obtained results from the experiments and analysis of each scenario, the following conclusions can be drawn with regard to the VoIP initiators and receivers:  
* Integrating the IEEE 802.11g, 802.11s standards with both voice codecs decreases the VoIP performance in scenarios with waypoint mobility and no mobility;
* Integrating the IEEE 802.11n with both voice codecs decreases the VoIP performance in scenarios where the nodes are distant from each other. The MOS values for VoIP initiators and receivers are analyzed and compared in Figure 19. Although in most scenarios the MOS values for the initiator and receiver are the same, there are a few scenarios where the VoIP initiators have better performance compared with the VoIP receivers. Figure 16: All scenarios’ end-to-end average delay comparison for: (**a**) VoIP initiators; (**b**) VoIP receivers. Figure 17: All scenarios’ average jitter comparison for: (**a**) VoIP initiators; (**b**) VoIP receivers.