Allocation of subcarriers of a wireless communications channel to antennas for transmission of said subcarriers from a multi-antenna transmitter, comprises selecting, for each subcarrier, the antenna with the most effective transmission performance against a predetermined performance criterion; and determining if subcarriers are evenly distributed amongst said antennas. If even distribution does not arise, then a reallocation sequence is performed. This comprises identifying, for an antenna having excessive subcarriers allocated thereto, the subcarriers allocated thereto and reallocating one of said subcarriers as required, said reallocated subcarrier being selected for reallocation on the basis of its impact on transmission performance.