9
Data transmission between a reader and a tag.
100
0
0.5
1
1.5
2
2.5
3
3.5
4
104
Vogt1
Vogt2
DFSA
Zhen
Query tree
Binary tree
AOS
ABS
Vogt1
Vogt2
DFSA
Zhen
Query tree
Binary tree
AOS
ABS
150 200 250 300
Number of tags (a) (b)
Total identification time delay (ms)
Total identification time delay (ms)
350 400 450 500 100
0
500
1000
1500
2000
2500
3000
3500
4000
150 200 250 300
Number of tags
350 400 450 500
FIGURE 9.10
Total identi?¬?cation delay of motionless tags. (a) Total identi?¬?cation delay (no quiet state). (b) Total identi?¬?cation
delay (quiet state).
Comparative Performance Analysis of Anticollision Protocols in RFID Networks 175
Query tree and binary tree, which belong to the tree-based protocol, show better
performance than the probabilistic protocols. They are, however, somewhat different in
total identi?¬?cation delay. There is not much of a difference in the performance of different
probabilistic protocols until the sample size becomes >250. The reason why Vogt??™s
methods have larger delays when sample size is over 300 is that they assume that the
maximum frame size is 256. In Zhen and DFSA, the predicted number of tags is employed
as the frame size, so they outperform Vogt??™s methods when the number of tags increases. It
is expected that both protocols show the similar results provided that Vogt??™s use the frame
size that is the same as the predicted number of tags.
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