Method and arrangement in a first base station for calculating a first location parameter α of a user equipment in order to improve beamforming accuracy. The first base station and the user equipment are comprised in a Coordinated Multiple Point “CoMP” communication system together with a second base station. The method comprises measuring a signal received from the user equipment, estimating a first parameter value α′ based on the measured signal, obtaining a second parameter value α″, based on an estimated second location parameter β of the user equipment, estimated at the second base station and calculating the first location parameter α, based on the first estimated parameter value α′ and the obtained second parameter value α″.