| 摘要 |
PROBLEM TO BE SOLVED: To provide a digital mobile communication system with which a mobile station moved outside the communication area of a base station can perform direct communications with a mobile station inside the communication area of the base station. SOLUTION: When the mobile station located outside the communication area detects the receiving level of a frequency F2 from the base station with a receiving level detecting part 27 and judges that the level is lower than a reference level by using a first deciding part 34, the mobile station switches the frequency in a receiving demodulating part 26 to a frequency F1 for direct communications and performs transmission to the mobile station inside the area. Each of mobile stations periodically monitors the signal of the frequency F1 and when such a signal is received, the request signal of direct communications is transmitted to the base station by the frequency F1. Then, a direct communication mode is started. The mobile station out of the area receives transmitted signals from a plurality of mobile stations inside the area, and on the basis of such receiving level data, the mobile station of the best receiving level data is selected by a second discriminating part 35. Then, direct communications are performed with that mobile station by the frequency F1. |
