CSL CS468 16-Port EPC CLASS 1 GEN 2 RFID READER
USER'S MANUAL, VERSION 2.0.1
Copyright © Convergence Systems Limited, All Rights Reserved
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8)
Fixed Q (Generic) Algorithm
• Fixed Q value
• Basis for all inventory algorithms.
• Optionally executes rounds until no tags are read.
• Optionally retries a rounds “n” times.
• Optionally flips A/B flag at end of round
This algorithm runs all inventory rounds with a single Q value. In this algorithm an inventory
cycle consists of one or more rounds, each of which will attempt to read every slot. The
number of slots to search is given by 2Q. For example, a Q of 7 will cause the algorithm to
search 128 slots on each round. One word of caution, if the time it takes to run the round is
greater that the frequency hop time (and the session is 0) or antenna dwell time, the round will
never complete.
9)
Dynamic Q Algorithm (1)
• Q adjusts up or down at the end of each round.
• Execu
tes repeated rounds until no tags are read when Q = Q minimum.
• Uses Qstart,Qmax and Qmin parameters to control the range of Q.
• MaxReps to limit time spent at each Q value.
• HighThres and LowThres to control how Q will adjust.
In algorithm 1, the value of Q is dynamically adjusted based on the periodic evaluation of the
relative frequency of RN16 timeouts vs EPC timeouts.
Each round is comprised of a Query and up to MaxReps queryReps.
The value of Q for the subsequent round is determined by the results of the current round. If
the number of RN16 timeouts is greater than the number of EPC timeouts multiplied by
thresHi, Q is decremented (presumed empty slots outnumber presumed collisions). If the
number of RN16 timeouts is less than the number of EPC time outs times thresLo, Q is
incremented (presumed collisions outnumber presumed empty slots). If the number of RN16
time outs falls between those two values, Q remains unchanged.
An inventory cycle is comprised of one or more inventory rounds, and is terminated when a
round is executed with Q = 0 and no tags read.
10)
Dynamic Q Algorithm (2)
–
Dynamic Q Adjust
• Almost identical to algorithm 1.
• Same control interface as algorithm 1.
• Uses QueryAdjust command to modify Q value
