1. A method for operating a receiver in a multiple-input multiple-output (MIMO) communication system, wherein the receiver includes a plurality of receiver antennas, wherein a transmitter of the MIMO communication system includes a plurality of transmitter antennas, the method comprising: receiving an estimated transmit vector that includes a plurality of candidate symbols, wherein the candidate symbols are estimates of respective transmit symbols simultaneously transmitted from the respective transmitter antennas; for each of the transmitter antennas, performing a set of operations using electronic circuitry, wherein the set of operations includes: for each bit within each candidate symbol in the estimated transmit vector, computing a soft information value for the bit, wherein said computing the soft information value includes: (a) determining a distance measure x i and a displacement vector y i for the bit, wherein the distance measure x i comprises a measure of distance between the candidate symbol and a closest competing symbol for the bit, wherein the displacement vector y i comprises a complex displacement between the candidate symbol and the closest competing symbol; and (b) computing the soft information value for the bit based on the distance measures x i , the displacement vector y i and on a measure d of inverse channel gain for the transmitter antenna.