A method comprising: receiving, by a receiver, a first signal, wherein the first signal comprises a modulated source signal transmitted on a first carrier over a communications channel, wherein the modulated source signal reflects a first source symbol mapped to a one of a plurality of signal constellation points, wherein each signal constellation point is associated with a different one of a plurality of signal clusters (303a,303b,303c,303d), wherein each signal cluster (303a,303b,303c,303d) reflects interference and/or noise effects with respect to the associated signal constellation point; acquiring, from the received first signal, a received representation of the modulated source signal with respect to the first source symbol; determining a plurality of first likelihood metrics, wherein each first likelihood metric is based on the received representation of the modulated source signal with respect to the first source symbol and a different one of a plurality of core parameters, whereby each core parameter is computed as a centroid (301a,301b,301c,301d) with respect to a different one of the signal clusters (303a,303b,303c,1303d) as received via the transmission on the first carrier over the communication channel; and determining the one signal constellation point and the first source symbol based on one or more of the first likelihood metrics, wherein each centroid (301a,301b,301c,301d) comprises a real centroid and an imaginary centroid, whereby the real centroid of a corresponding signal cluster (303a,303b,303c,303d) is calculated as a mean over a number of received real representations of the modulated training signal with respect to training symbols in the corresponding signal cluster (303a,303b,303c,303d) and the imaginary centroid of a corresponding signal cluster (303a,303b,303c,303d) is calculated as a mean over a number of received imaginary representations of the modulated training signal with respect to training symbols in the corresponding signal cluster (303a,303b,303c,303d). receiving, by a receiver, a first signal, wherein the first signal comprises a modulated source signal transmitted on a first carrier over a communications channel, wherein the modulated source signal reflects a first source symbol mapped to a one of a plurality of signal constellation points, wherein each signal constellation point is associated with a different one of a plurality of signal clusters (303a,303b,303c,303d), wherein each signal cluster (303a,303b,303c,303d) reflects interference and/or noise effects with respect to the associated signal constellation point; acquiring, from the received first signal, a received representation of the modulated source signal with respect to the first source symbol; determining a plurality of first likelihood metrics, wherein each first likelihood metric is based on the received representation of the modulated source signal with respect to the first source symbol and a different one of a plurality of core parameters, whereby each core parameter is computed as a centroid (301a,301b,301c,301d) with respect to a different one of the signal clusters (303a,303b,303c,1303d) as received via the transmission on the first carrier over the communication channel; and determining the one signal constellation point and the first source symbol based on one or more of the first likelihood metrics, wherein each centroid (301a,301b,301c,301d) comprises a real centroid and an imaginary centroid, whereby the real centroid of a corresponding signal cluster (303a,303b,303c,303d) is calculated as a mean over a number of received real representations of the modulated training signal with respect to training symbols in the corresponding signal cluster (303a,303b,303c,303d) and the imaginary centroid of a corresponding signal cluster (303a,303b,303c,303d) is calculated as a mean over a number of received imaginary representations of the modulated training signal with respect to training symbols in the corresponding signal cluster (303a,303b,303c,303d).