| 摘要 |
<P>PROBLEM TO BE SOLVED: To enable a search of an illegal radio source correctly and easily. <P>SOLUTION: A radio terminal 3 performs a carrier sensing operation in an operating frequency band when the terminal tries to start communication and when the terminal it receives radio waves from surroundings, the radio terminal 3 subjects signals received from the surroundings to a demodulating process, and when the radio terminal 3 is incapable of demodulating because the signals are not provided with pilot signals etc. it is determined that the received signals are illegal radio waves, and interference information detected from the received signals is transmitted to a control station 1. It is supposed that an illegal radio wave source is present in surroundings, so that communication is not maintained in the operating frequency band, and the radio terminal 3 is switched to the other circuit so as to keep communication in the other frequency band. When the radio waves are not received from the surroundings, it is supposed that no interference radio wave is present in the operating frequency band, the communication of modes desired by a user (speech communication, packet communication, etc.) is started in the operating frequency band. <P>COPYRIGHT: (C)2008,JPO&INPIT |
