Preserving ASC at the boundary of
two consecutive frames makes it possible that the tree search starts from the readable
cycles of the last frame.
8.6.2 Frame Termination
To terminate the frame at once after identifying all tags, the reader of ABS acts as the tag
which has the largest ASC. The reader determines the end point of the frame with a PSC
and a terminated slot counter (TSC). PSC of the reader represents the number of tags
recognized successfully. In a readable cycle, the reader adds 1 to PSC. TSC signi?¬?es the
number of tag sets in the reader??™s range. If a collision occurs, the reader increases TSC by 1
because the number of tag sets has increased. When a reading cycle of type ??????idle??™??™ is
encountered, the reader decreases TSC by 1. This is to re?¬‚ect the effect of the elimination of
idle cycles. As soon as PSC is greater than TSC, the reader concludes that all tags have been
recognized and transmits the command terminating the frame to all tags. For fast identi-
?¬?cation in the next frame, the reader preserves TSC after the end of the frame.
In an environment with multiple readers, an arriving tag can be recognized with its ASC
given by other readers. If an arriving tag has ASC less than TSC, it is obvious that the
arriving tag has the same ASC with a staying tag or a leaving tag and is recognized by
the reader in the following frame.
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