1. A method for detecting transmitted data in a broadband communication system with multiple transmit antennas and receive antennas, the method comprising: receiving, at a receiver of the communication system, a received symbol vector wherein each symbol of the received symbol vector is from a corresponding antenna of the multiple receive antennas, wherein the received symbol vector corresponds to a transmitted symbol vector that are modulated according to transmitted data bits using a modulation scheme; performing an initial symbol estimation for each symbol of the transmitted symbol vector based on the corresponding received symbol vector; generating a candidate symbol set for each of the initially estimated symbol of the transmitted symbol vector, wherein the number of candidate symbols in each of the candidate symbol set is a predetermined number; generating a combined set of candidate symbol vectors by using the candidate symbol sets corresponding to the initially estimated symbols; and computing soft information of the transmitted symbol vector using every candidate symbol vector of the combined set.