An apparatus and a method in a radio communications system. The apparatus in the radio communications system includes an estimation unit and a statistics collection unit. The estimation unit is used for estimating a signal receiving strength of each of multiple transmission positions, compared with a signal transmission strength of each of one or more possible transmission positions of a first-type node of a to-be-test communications system on a transmission resource block. The statistics collection unit is used for collecting, according the estimation result, statistics on power space distribution of the first-type node of the to-be-tested communications system.