A supporting radio base station (100) comprises an IQ sample provider (110) for extracting, in a selected subset of the available frequency band (A) and/or from a selected subset of the available antennas (B), so-called complementary IQ samples based on received radio signals including a radio signal originating from an uplink transmission of at least one UE served by a serving radio base station (200). The supporting radio base station (100) comprises an IQ sample transmitter (120) for transmitting the complementary IQ samples to the serving radio base station (200) to enable the serving radio base station to decode user data of the uplink transmission based on the complementary IQ samples together with own IQ samples provided by the serving radio base station (200). This will provide significant savings of bit rate for the exchange of IQ samples between the radio base stations.