The invention relates to a method to determine a transmission mode to be used at a MIMO-transmitter. The determination of an optimum transmission mode is done at the side of a MIMO-receiver. The receiver calculates for each stream of a maximum number of received streams an effective SINR-value for a given first linear dispersion code LDC. The SINR value of each stream is used to select, according to a desired BER target, a suitable modulation alphabet for each stream. A sum-rate is calculated over all streams and a first stream with a minimum effective SINR value is separated and is not considered furthermore. A linear dispersion code LDC with a smaller code rate than the first linear dispersion code LDC is selected and SINR-values for the remaining N-I streams are calculated. A new sum-rate is obtained accordingly. In case that the new sum rate of the remaining N-I streams is smaller than the sum rate of N streams, the sum-rate calculation is terminated. In all other cases, the step of separation of a stream with smallest effective SINR, the step of selection of a linear dispersion code LDC with a smaller code rate than the linear dispersion code LDC before and the step of calculation of SINR value for remaining streams are repeated accordingly. The most suitable code rate of the linear dispersion code LDC is selected after the termination and the code rate is reported to the transmitter, together with assigned quantized effective SINR value of each stream, to allow a final decision about a optimum transmission mode at the transmitter.