Analysis of Quality of Service in Wimax networks

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Figure 8 Average Jitter with number of nodes for BE service flow 
Figure 8 shows the average jitter for BE traffic with G.711 codec. The average 
jitter is seen to increase steadily. Jitter is the measure of the variability over time of the 
latency across a network. Increasing jitter implies that, the packets arrive at varying 
delay at the receiver. This reflects adversely in the perceived quality especially in case of 
VOIP traffic. Each packet contains a voice sample sent from the sender. It the packets 
are not received with the same delay at the receiver, the voice quality appears to be 
degraded. 
Service Flow Type: Best Effort (BE) 
Traffic Type: VOIP 
VOIP Codec: G.711 ((64kbps): 80 bytes frame, 160 bytes payload, 50 pkts per sec.) 

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Average Delay
0.000166
0.0001665
0.000167
0.0001675
0.000168
0.0001685
0.000169
2
4
6
8
10
Number of nodes
S
ec
onds
Figure 9 Average Delay with number of nodes for BE service flow 
Average delay does not show a lot of variation as the number of nodes increases.
This is seen in Figure 9. 
4.1.2 Results for VOIP traffic over Real Time Polling Service Flow 
In this section results are presented for VOIP traffic over rtPS service flow.
Figure 10 through Figure 13 show the variation of throughput, packet loss, average jitter 
and average delay for VOIP traffic using G.711 codec.
Service Flow Type: Best Effort (BE) 
Traffic Type: VOIP 
VOIP Codec: G.711 ((64kbps): 80 bytes frame, 160 bytes payload, 50 pkts per sec.) 

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39
Thoughput
0
100
200
300
400
500
600
2
4
6
8
10