There is provided a method of operating a mobile device in a heterogeneous communications network, the heterogeneous communications network comprising first and second base stations, the first base station having a lower transmission power than the second base station and being within the coverage area of the second base station, the method comprising obtaining measurements of the quality of signals transmitted between the first base station and the mobile device and/or the second base station and the mobile device; and analyzing the measurements of the quality to determine whether the mobile device is located in an imbalanced region or part of an imbalanced region between the first and second base stations.