Patent ID: 8483328

Claim:
A communications apparatus, comprising: an input configured to receive a digital signal that represents a symbol transmitted over a transmit antenna; a first decoder configured to perform a computation of a set of soft metrics of the transmitted symbol, wherein the computation has a complexity of 2 B(K−1) where B is a number of bits transmitted per symbol on an antenna, and K is a number of transmit antennas, the set of soft metrics to indicate a likelihood of a state of bits of the symbol, at least in part by computing an estimate of a first element of the transmitted symbol, based on the estimate, making a hard decision on values of bits of the first element to form a hard-decided first element, computing soft metrics for second to K th elements of the transmitted symbol at least partly in terms of the hard-decided first element, computing a soft metric for at least the first element of the transmitted symbol, and obtaining the soft metrics of the transmitted symbol in terms of the soft metric for the first element of the transmitted symbol and the soft metrics for the second to K th elements; and a second decoder configured to utilize the set of soft metrics to determine a symbol value corresponding to the transmitted symbol.