摘要 |
A base station has a first antenna for emitting radio waves at a first tilt angle and a second antenna for emitting radio waves at a second tilt angle different from the first tilt angle. If the antennas have different propagation lengths, a transmission diversity gain is not obtained and interference occurs in an adjacent area. In such a case, when one antenna having a shorter propagation length, which means less interference in the adjacent area, is used for transmission, the throughput of each terminal is increased at the area. For example, a controller changes two antenna transmission to one antenna transmission when the difference between the reception qualities of signals sent from the base station and an adjacent base station adjacent to the base station is smaller than a predetermined reference, the reception qualities being measured at the terminal.
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