Analysis of Quality of Service in Wimax networks

Num ber of Nodes
seco
n
d
s
 
Figure 29 Average Delay with number of nodes for BE service flows 
Figure 29 shows the variation of average delay for BE service flow. As seen from 
the figure, the delay steadily increases as the number of nodes increases. 
Service Flow Type: Best Effort (BE)
Traffic Type: Video 
Video Parameters:64kbps H.263 

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4.2.2 Results for video traffic over Real Time Polling Service Flow 
Figure 30 to Figure 33 show the QoS parameters for video traffic as number of 
nodes increase. The rtPS service flow used during set up. 
Throughput
0
100
200
300
400
500
600
1
2
3
4
5
10
Num ber of nodes
kb
p
s
 
Figure 30 Throughput with number of nodes for rtPS service flows 
Figure 30 shows variation of throughput as number of nodes with streaming video 
traffic increase. The throughput increases as the number of nodes increases. The value 
of throughput for 64kbps video sample with one node is close to 63.5 kbps. For 10 nodes 
it is about 500 kbps. This value is lower than expected. The reason for lower value of 
throughput is higher packet loss incurred at higher nodes. 
Service Flow Type: Real Time Polling Service (rtPS)
Traffic Type: Video 
Video Parameters:64kbps H.263 

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PacketLoss
0
2
4
6
8
10
12
14
16
18
1
2
3
4
5
10
Num ber of nodes
%
 
Figure 31 Packet Loss with number of nodes for rtPS service flows 
Figure 31 shows a very high level of packet loss at higher number of nodes. This 
is indicative of the overhead that rtPS service flows carry. In rtPS service flow, the BS 
provides unicast polling opportunities for the SS to request bandwidth. Thus it has a 
request overhead as compared to UGS service flow. But rtPS is more efficient for service 
that generates variable-size data packets. This is more evident in section 4.2.4 which has 
the comparative graphs for the three service flows for the video traffic. 
Service Flow Type: Real Time Polling Service (rtPS) 
Traffic Type: Video 
Video Parameters:64kbps H.263 

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Average Jitter
0
0.0005
0.001
0.0015
0.002
0.0025
0.003
0.0035
0.004
0.0045
1
2
3
4
5
10