The invention relates to reducing interference in indoor cells in a wireless cellular communication network. Outdoor and indoor base stations operate at a common uplink carrier frequency. The indoor base station monitors an uplink inter-cell interference level, and, responsive to the uplink inter-cell interference level reaching a predetermined threshold level, synchronizes with an uplink transmission signal received from at least one potentially interfering user equipment which is connected to the outdoor base station but outside the downlink coverage area of the indoor base station. The interfering user equipment is commanded, via a downlink control channel of the outdoor base station, to lower the transmission power of the uplink transmission signal, and to thereby decrease the uplink inter-cell interference level on indoor base station.