Analysis of Quality of Service in Wimax networks

Average Jitter on Log Scale
1.00E-11
1.00E-09
1.00E-07
1.00E-05
1.00E-03
1.00E-01
1.00E+01
2
4
6
8
10
Number of Nodes
Log of
 A
ve
ra
ge
 J
it
te
r
UGS
RTPS
BE
 
Figure 20 Average Jitter with number of nodes for all service flows 
Service Flow Type: Combined 
Traffic Type: VOIP 
VOIP Codec: G.711 ((64kbps): 80 bytes frame, 160 bytes payload, 50 pkts per sec.) 

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49
Average Delay
0.000166
0.0001665
0.000167
0.0001675
0.000168
0.0001685
0.000169
2
4
6
8
10
Number of nodes
seco
n
d
s
UGS
RTPS
BE
 
Figure 21 Average Delay with number of nodes for all service flows 
Figure 21 shows average delay variation for the three service flows. The values 
for UGS and rtPS flows fall very close to each other overlapping the two lines in the 
graph. The BE effort service flow has the higher delay as compared with UGS and rtPS 
flows 
In conclusion, it is observed that UGS service flow has the highest throughput, 
least packet loss and lowest average jitter. This makes it best suited for VOIP traffic.
UGS service flow is designed to handle fixed sized packets generated a regular interval.
The simulation results validate that. 
Service Flow Type: Combined 
VOIP Codec: G.711 ((64kbps): 80 bytes frame, 160 bytes payload, 50 pkts per sec.) 

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50
4.1.5 Study over various VOIP codecs 
The effect of number of nodes with VOIP traffic over various QoS parameters 
were also analyzed for different VOIP codecs as explained in Table 3. The trends in 
various parameters are similar to that of G.711 codec details of which were already 
presented. In this section, the overall effect of each parameter is presented in a combined 
manner.