| 摘要 |
PROBLEM TO BE SOLVED: To provide an ID tag system where an ID tag reader and an ID tag transmit proper power for communication depending on the distance between them. SOLUTION: The ID tag reader transmits a notice request of a reception power level to the ID tag (step A3), and the ID tag informs the ID tag reader about the reception power level (step A4). Then the ID tag reader adjusts a transmission power level to the ID tag corresponding to the informed reception power level (steps A5-A8). |
