Information Technology Reference
In-Depth Information
Also, the superiority of the verification rate of the adaptive scheme is obvious too
as Fig. 8. With the changeable packet error rate which varies randomly between 0 and
1 and the fixed initial parameters
m
/
n
, the verification rate of the system is not as
expected. On the other hand, the adaptive scheme can achieve an ideal verification
rate in any condition.
verification rate of fixed scheme
verification rate of adaptive scheme
1.0
0.8
0.6
0.4
0.2
0.0
1/8
2/8
3/8
4/8
5/8
6/8
7/8
m/n value
Fig. 8.
Verification rate under unstable environment
At the same time, the chosen nodes will count the decoding time of every block and
compared to the threshold value
t
. Here we set
t
= 250ms and
t
0
= 103ms, so we can
get the Table 4 as followed (the bold italic column presents the time
t
0
).
Table 4.
The time delay values changing table
No.
n
value the time delay near the critical point (ms)
1 128 276.4 313.7 263.2
290.1
203.3 236.1
2 128 234.7 229.2 227.8
231.6
303.4 343.7
3 64 225.9 198.3 246.1
209.3
258.0 269.4
4 64 257.3 254.9 273.4
289.0
226.1 231.8
5 32 193.2 197.7 215.2
220.4
267.9 258.5
6 32 265.9 282.3 280.7
274.1
238.4 240.2
We can get from the Table 4 that when the time delay values exceed the threshold
value
t
for
t
0
time, then the value of
n
would be decreased to reduce the time delay
(the 1st, 4th and 6th rows). Otherwise the delay values keep under the threshold value
t
for
t
0
time, the value of
n
would be increased (the 2nd, 3rd and 5th rows) as Fig. 9.
5
Conclusion
We can see from the experiment results that our protocol is efficient in adapting itself
in all kinds of network environment especially when the network changes frequently.
