| 摘要 |
PROBLEM TO BE SOLVED: To allow a radio communication system to automatically select a relay communication mode where mobile stations make communication with a relay of a base station or a direct communication mode where the mobile stations make direct communication not through the base station. SOLUTION: A base station transmits a 1st carrier signal f1 for communication with a mobile station and uses a 2nd transmission section 20 to always transmit a 2nd carrier signal f2. The mobile station always receives the 2nd carrier signal f2, a reception level detection section 37 detects a reception level of the f2, and a bit error rate detection section 39 detects a bit error rate of received data by the 1st carrier signal f1. When the detected reception level is a reference level or below, the bit error rate exceeds a reference value and the state is consecutive for a prescribed time (1st timer section 41), the mobile station selects a direct communication mode using an exclusive frequency f4 from a relay communication mode. The base station instructs an opposite mobile station to allow the opposite mobile station to select the direct communication mode from the relay communication mode. |
