A method for predicting performance of a multi-input multi-output (MIMO) receiver that receives a plurality of MIMO streams, each MIMO stream being transmitted by a transmitter applying a different modulation scheme, the method comprising: exchanging information between a model of an equalizer (310, 410) and a model of a soft demapping unit (320, 420) in an iterative way to generate a set of SNR values associated with the MIMO streams that corresponds to a plurality of updated estimates of an output SNR by the model of the equalizer of the last iteration, wherein exchanging information comprises: providing a plurality of estimates of an output SNR by the model of the equalizer (310, 410) to the model of the soft demapping unit (320, 420); and providing a plurality of estimates of an a-posteriori variance of a plurality of transmitted signals by the model of the soft demapping unit to the model of the equalizer, where the transmitted signals are received in the form of the plurality of MIMO streams, wherein the model of the soft demapping unit is mapping said plurality of estimates of an output SNR to said plurality of estimates of an a-posteriori variance of a plurality of transmitted signals by means of a mapping function that depends on the modulation constellation size and that is independent of an a-posteriori mean of the transmitted symbols, wherein the model of the soft demapping unit is multiplying values of said mapping function by correction factors associated with the MIMO streams, each correction factor being dependent on the modulation scheme of the respective MIMO stream, and wherein the model of the equalizer uses the plurality of estimates of the a-posteriori variances provided by the soft demapping unit to the plurality of updated estimates of the output SNR. exchanging information between a model of an equalizer (310, 410) and a model of a soft demapping unit (320, 420) in an iterative way to generate a set of SNR values associated with the MIMO streams that corresponds to a plurality of updated estimates of an output SNR by the model of the equalizer of the last iteration, wherein exchanging information comprises: providing a plurality of estimates of an output SNR by the model of the equalizer (310, 410) to the model of the soft demapping unit (320, 420); and providing a plurality of estimates of an a-posteriori variance of a plurality of transmitted signals by the model of the soft demapping unit to the model of the equalizer, where the transmitted signals are received in the form of the plurality of MIMO streams, wherein the model of the soft demapping unit is mapping said plurality of estimates of an output SNR to said plurality of estimates of an a-posteriori variance of a plurality of transmitted signals by means of a mapping function that depends on the modulation constellation size and that is independent of an a-posteriori mean of the transmitted symbols, wherein the model of the soft demapping unit is multiplying values of said mapping function by correction factors associated with the MIMO streams, each correction factor being dependent on the modulation scheme of the respective MIMO stream, and wherein the model of the equalizer uses the plurality of estimates of the a-posteriori variances provided by the soft demapping unit to the plurality of updated estimates of the output SNR. providing a plurality of estimates of an output SNR by the model of the equalizer (310, 410) to the model of the soft demapping unit (320, 420); and providing a plurality of estimates of an a-posteriori variance of a plurality of transmitted signals by the model of the soft demapping unit to the model of the equalizer, where the transmitted signals are received in the form of the plurality of MIMO streams, wherein the model of the soft demapping unit is mapping said plurality of estimates of an output SNR to said plurality of estimates of an a-posteriori variance of a plurality of transmitted signals by means of a mapping function that depends on the modulation constellation size and that is independent of an a-posteriori mean of the transmitted symbols, wherein the model of the soft demapping unit is multiplying values of said mapping function by correction factors associated with the MIMO streams, each correction factor being dependent on the modulation scheme of the respective MIMO stream, and wherein the model of the equalizer uses the plurality of estimates of the a-posteriori variances provided by the soft demapping unit to the plurality of updated estimates of the output SNR.