The present invention concerns a transmission method in a wireless telecommunication system including at least a base station intended to communicate with terminals over bidirectional communication channels, each channel supporting frames being divided into downlink sub frames and uplink sub frames, each downlink sub frame including a number of symbols intended to be transmitted to at least two terminals, wherein the transfer of at least one supplementary symbol between the base station and at least one terminal that can receive or transmit said at least one supplementary symbol during the time delay is enabled. At least part of each symbol comprised in the sub frame are transferred according to a first transmission power coefficients and at least at least one supplementary symbol is transferred according to second transmission power coefficients.