1. A method of detecting data in a received multiple-input-multiple-output (MIMO) signal, the method comprising: receiving a signal that represents a set of data symbols transmitted over a communication channel; determining possible bit values for a single data symbol of the set of data symbols based on the received signal; and determining possible bit values for other data symbols of the set of data symbols based on the possible bit values for the single data symbol, wherein determining the possible bit values for the other data symbols includes: for each bit included in the other data symbols, determining a first value by combining i) a first soft metric indicating a likelihood of a state of the bit given the received signal, and ii) a second soft metric representing an a priori probability (APP) for the bit, wherein the APP for the bit is received from a decoder, wherein the first soft metric is not based on the APP for the bit, and determining the possible bit values for the other data symbols based on the first values.