| 摘要 |
PROBLEM TO BE SOLVED: To secure radio transmission right with whole radio terminal units and to efficiently collect data by transmitting transmission timing transmitted from a main radio unit by means of giving time differences by individual terminal radio units. SOLUTION: At the time of communication with terminal units 13a-13c, a main transmission unit transmits data to the respective terminal units 13a-13c, by giving random waiting time differences 33a, 33b, 33c and so on for respective time slots 31a, 31b, 31c and so on. Synchronization is avoided and transmission right with the respective terminal units 13a-13c is secured. The second terminal unit 13b whose waiting time is the shortest receives question burst 35 from the main transmission unit following a usable recognition area 34 after waiting time 33b from reference timing 32a and gives meter-reading data, for example. When the third terminal unit 13c whose waiting time is the shortest next is unable to give an answer in the second time slot some reason, the first terminal unit 13a whose waiting time is the shortest next gives the answer and the third unit 13c gives the answer in the third slot. |
