A composite signal including a plurality of component signal streams is processed using QR-decomposition to detect symbols and calculate a decision metric for each of the signal streams (202). Soft serial interference cancellation is performed on the composite signal based on the symbols detected for different ones of the signal streams and a ranking of the signal streams (204). The symbols are re-detected and the decision metric re-calculated for each signal stream based on soft serial interference cancellation results (206). The different decision metric calculations for at least one of the signal streams are compared to determine whether symbol detection is more accurate with or without soft serial interference cancellation (208). The signal streams are decoded using symbols detected based on soft serial interference cancellation results when symbol detection is determined to be more accurate with soft serial interference cancellation (210). Otherwise, the streams are decoded based on the symbols detected using QR-decomposition (210).