It is presented a method for mapping one or more codewords to antennas of the same cell under control of a radio base station of a cellular communication system, wherein the antennas are distributed over at least two different sites. The method is performed in a radio base station and comprises: determining a distribution matrix such that each one of the one or more codewords is substantially only mapped to at least two antennas located at only one site; and applying the distribution matrix to the one or more codewords. Corresponding radio base stations, computer program and computer program product are also presented.
