Analysis of Quality of Service in Wimax networks

Num ber of nodes
kb
p
s
Figure 10 Throughput with number of nodes for rtPS service flow 
Similar to the BE service flow case, the throughput increases steadily as the 
number of nodes increases. The throughput is about 116 kbps for 2 nodes and goes up to 
519 kbps. The behavior is expected.
Figure 11 shows the variation of packet loss as number of nodes increase. 
Service Flow Type: Real Time Polling Service(rtPS) 
Traffic Type: VOIP 
VOIP Codec: G.711 ((64kbps): 80 bytes frame, 160 bytes payload, 50 pkts per sec.)

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40
Packet Loss %
0
0.02
0.04
0.06
0.08
0.1
0.12
0.14
0.16
2
4
6
8
10
Num ber of nodes
%
Figure 11 Packet Loss with number of nodes for rtPS 
The packet loss increases as number of nodes increase for the VOIP traffic. In 
rtPS service flow, the bandwidth allocation is done using polling. The BS polls the MS 
to send a bandwidth request. Hence, there are lot of control packets that go between the 
MS and the BS other than the actual data packets. This is the reason for increased packet 
loss. 
Service Flow Type: Real Time Polling Service(rtPS) 
Traffic Type: VOIP 
VOIP Codec: G.711 ((64kbps): 80 bytes frame, 160 bytes payload, 50 pkts per sec.) 

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41
Agerage Jitter
0.00E+00
5.00E-11
1.00E-10
1.50E-10
2.00E-10
2.50E-10
3.00E-10
3.50E-10
4.00E-10
4.50E-10
2
4
6
8
10
Number of nodes
S
eco
n
d
s
Figure 12 Average Jitter with number of nodes for rtPS 
Figure 12 shows the variation of average jitter for VOIP traffic over rtPS service 
flow. The values of jitter are extremely low, and the pattern seen here is not very 
significant. 
Service Flow Type: Real Time Polling Service(rtPS) 
Traffic Type: VOIP 
VOIP Codec: G.711 ((64kbps): 80 bytes frame, 160 bytes payload, 50 pkts per sec.) 

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42
Average Delay
0.000167165
0.000167165
0.000167165
0.000167165
0.000167165
0.000167166
0.000167166
0.000167166
0.000167166
2
4
6
8
10