Patent ID: 7218955
Filing Date: 2007-05-15
Classification: H01Q

Abstract:
1. A method for deciding tilt angles of antennas having directivity in a vertical plane, which are provided in a plurality of radio base stations constituting a radio communication system, said method comprising: a first step of selecting an antenna whose tilt angle is to be reduced; a second step of calculating a deterioration rate of the system more than once, by changing the tilt angle, at the time when a tilt angle of the antenna selected in the first step is reduced; a third step of selecting an antenna whose tilt angle is to be increased; a fourth step of calculating a deterioration rate of the system more than once, by changing the tilt angle, at the time when a tilt angle of the antenna selected in the third step is increased; a fifth step of outputting the tilt angle corresponding to the smallest deterioration rate in the deterioration rate of the system calculated in the second step and the deterioration rate of the system calculated in the fourth step a sixth step being performed after the first step and the second step, wherein it is determined whether processes of the first step and the second step are to be repeated; a seventh step being performed after the third step and the fourth step, wherein it is determined whether processes of the third step and the fourth step are to be repeated; and wherein the deterioration rate is a ratio of the points where reception power or quality is lower than a predetermined value within specified coverage.