Patent ID: 6999764

Claim:
A method for changing over to a different frequency at a cellular phone system, in which a mobile communication terminal, a first base station and a second base station, and a base station controlling apparatus are provided, wherein: said first base station communicates with said mobile communication terminal by setting a channel using a first frequency, and said second base station communicates with said mobile communication terminal by setting a channel using a second frequency, and said mobile communication terminal is controlled to measure first reception quality in said first frequency during the communication with said first base station by setting a channel, and also said mobile communication terminal is controlled to measure second reception quality in said second frequency corresponding to said first reception quality during the communication with said first base station by setting the channel, and said mobile communication terminal is controlled to communicate with said second base station by changing over the channel from said first base station to said second base station corresponding to said first and second reception quality, wherein: said method for changing over to a different frequency, comprising the step of: changing the condition of measuring said second reception quality corresponding to the traffic in said first frequency by said base station controlling apparatus.