Analysis of Quality of Service in Wimax networks

Number of Nodes
%
BE
RTPS
UGS
 
Figure 39 Variation of Packet loss for all service flows for video traffic 
Figure 40 shows the variation of average jitter with all three service flows. To 
make the comparison easier a logarithmic scale is used. From the figure it shows that the 
jitter is very constant for UGS flow. However, rtPS flow has lower jitter than UGS 
service flow and it remains more or less constant. On the other hand, for single node, BE 
service flow has the lowest jitter. As the nodes increase, however, the jitter starts 
increasing. Thus when lot of network resources are available video traffic over BE 
service flow introduces the least jitter. However, as the nodes increase, the network 
resources get divided between all the nodes. Thus, it can be concluded that, the from 
average jitter consideration, for video streaming traffic, rtPS service flow is best suited.
When different video frames arrive at the receipient, it there is a lot of jitter, the video 
Service Flow Type: Combined 
Traffic Type: Video 
Video Parameters:64kbps H.263 

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does not appear to run smoothly. Thus average jitter is indicative of quality for video 
streaming. 
Average Jitter
0.0001
0.001
0.01
0.1
1
1
2
3
4
5
10
Number of nodes
L
o
g
 o
f 
A
verag
e Ji
tt
er
BE
RTPS
UGS
 
Figure 40 Variation of Average jitter for all service flows for video traffic 
Figure 41 shows the average delay for the three service flows as the number of 
nodes increase. UGS has higher delay as compared with BE and rtPS flows, although, 
the delay variation is less for UGS. This is because of UGS offers fixed grants on a 
periodic basis. There is no bandwidth request mechanism in BE traffic. Data is sent 
whenever resources are available and not required by any other scheduling-service 
classes. As the number of nodes increase the average delay increases rapidly for BE 
service flow as compared to rtPS service flow. 
Service Flow Type: Combined 
Traffic Type: Video 
Video Parameters:64kbps H.263 

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Average Delay
0
0.002
0.004
0.006
0.008
0.01
0.012
0.014
0
2
4
6
8
10
12