| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a radio tag reader capable of attempting the next communication by appropriately estimating whether it is highly possible for a communication failure to be caused by noise or collision occurrence. <P>SOLUTION: A control unit of a reader/writer detects the number B of tags each of which an ID can be acquired and the number C of communication slots in each of which a communication error occurs (step S1)in an anti-collision sub-round and estimates whether a degree of noise mixture is high or low and whether frequency of collision occurrence is high or low for a received signal on the basis of these detected numbers and the number A of empty communication slots (steps S3, S4). If the degree of noise mixture is estimated to be high, reception sensitivity is reduced (step S7). If the frequency of collision occurrence is estimated to be high, the total number S of communication slots for the next communication is increased (step S6). If both the degree of noise mixture and the frequency of collision occurrence are estimated to be low, the total number S of communication slots to be set for the next communication is decreased (step S5). <P>COPYRIGHT: (C)2008,JPO&INPIT |
