| 摘要 |
PROBLEM TO BE SOLVED: To eliminate interference to other adjacent radio base stations by shifting a timing by more than one slot from a transmission timing of other radio base stations and sending a downward control channel. SOLUTION: When a radio base station performs startup (ST1), first, a downward control channel of an adjacent radio base station is searched (ST11), and if UW is not detected (ST12), that is, there is no other base station in the neighborhood, carrier sensing of a control carrier is performed at an optional transmission slot position to confirm that an interference wave does not exist, and a downward control channel is sent (ST2 to 4). On the other hand, when UW is detected (ST12), a detected UW position is once synchronized with a sending position of the downward control channel of a radio base station (ST13), then, carrier sensing of a control channel is performed at a slot position which is separated by more than one slot from a synchronized slot position (ST14) to confirm that an interference wave does not exist and a downward control channel is sent (ST3 to 4). |
