The probabilistic tag anticollision protocols adapting quiet state of tags outperform since
the number of tags is small in the initial part. The reader performs the identi?¬?cation
operation with a small number of tags and makes them sleep. In this case, the size of
population is maintained at small size. On the other hand, due to the fact that the tags
which were already identi?¬?ed in the pervious identi?¬?cation process rejoin the identi?¬?cation
176 RFID Handbook: Applications, Technology, Security, and Privacy
operation in the current process in deterministic tag anticollision protocols, every process
has more tags than the probabilistic tag anticollision protocols adapting quiet state. The
average number of tags is 200.
The probabilistic tag anticollision protocols without using the quiet state of the tag
cannot identify 5000 tags with 30 ms interval due to the rejoining of identi?¬?ed tags. AQS
and query tree have similar performance, and the performance of the binary tree is not
good. However, the binary tree can identify all tags under the interval of 0.026 per
incoming tag. It shows that the binary tree can identify all tags when the population is
200 and 37 incoming tags per second to the reader??™s range.
The identi?¬?cation delay, the time to identify all tags within a reader??™s range, is a critical
metric. In this chapter, we have de?¬?ned a new metric as the time taken to identify if a tag
left a reader??™s range after the reader had recognized a tag.
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