Systems and methods for detecting data in a multiple input/multiple output signal. The method includes receiving a first signal associated with a first data value and a second signal associated with a second data value. A distance value between the received second signal and each possible second data value is calculated. Coordinates for a hypothetical first signal in light of a first possible second data value are calculated, and the first coordinate value is quantized to a nearest constellation point. A distance value between the received second signal and each possible second data value is calculated using the calculated constellation points. A determination is made of a log-likelihood ratio based on the determined distance values.