METHOD FOR MAINTAINING COMMUNICATION LINK

PROBLEM TO BE SOLVED: To maintain communication between a slave station and a communication network through the use of a controller and the communication network when the salve station is outside the coverage area of a main station. SOLUTION: When a slave station is in a piconet (wireless network having main station and one or more slave stations), the slave station is in the communication range of the main station by using a communication channel on a frequency band fband (1). When the slave station moves outside the piconet, the channel is switched to the different communication channel of the frequency band fband (1) so that it in the communication range of a controller and communication can be executed with the controller. When the slave station moves outside the communication range of the controller, it comes in the communication range of the communication network or the base station, and the channel is switched to the communication channel on the different frequency band fband (2).