Small collisions activate small tag
communication overhead. ABS has the shortest delay because it eliminates many idle
cycles. AQS generates more idle cycles than others due to additional queries to guarantee
recognizing all tags. On the other hand, AQS makes less collision and less tag communication
than ABS because idle cycles assist arriving tags to avoid con?¬‚icting with other tags.
8.7.2 Impact of Tag Movement
We evaluate the performance by increasing the tag velocity. Figure 8.8 presents the
simulation results obtained by varying the maximum MPF. We normalize the measured
4000
3500
3000
2500
2000
1500
1000
500
0
200 600 1000 1400 1800 2200
No. of tags
No. of reading cycles
2600 3000 3400 3800 4200
Binary
Query
AQS
ABS
(c)
0
100
200
300
400
500
600
700
200 600 1000 1400 1800 2200
No. of tags
No. of transmitted bits
2600 3000 3400 3800 4200
Binary
Query
AQS
ABS
(d)
FIGURE 8.7 (continued)
(c) Identi?¬?cation delay. (d) Tag communication overhead.
Adaptive Tag Anticollision Protocols for RFID Passive Tags 153
0
0.2
0.4
0.6
0.8
1
1.2
1.4
No. of collisions
Binary
Query
AQS
ABS
0 1 2 3 4 5
Maximum MPF (m/frame)
6 7 8 9 10
(a)
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
No. of idle cycles
Binary
Query
AQS
ABS
0 1 2 3 4 5
Maximum MPF (m/frame)
6 7 8 9 10
(b)
0
0.5
1
1.
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