| 摘要 |
PROBLEM TO BE SOLVED: To avoid the occurrence of asynchronous interference in a part on which two radio zones constituted of respectively different master stations are overlapped. SOLUTION: Virtual master stations 501, 502 are located on positions where mutual signals can't be received and a slave station 503 is located on a part where areas covered by respective virtual master stations 501, 502 are overlapped. If the virtual master station 502 sends an interference inspection signal by a certain fixed number of times in order to try communication by using a channel ch1 when the virtual master station 501 communicates with the slave station 503 by using the channel ch1, errors are generated in the slave stations 503 by the fixed number of times and sends an interference notification signal. The virtual master station 502 receiving the interference notification signal understands the occurrence of asynchronous interference in the area covered by the station itself, judges that the channel ch1 can't be used and executes communication by using the other channel. |
