Patent ID: 8218671

Claim:
A receiving apparatus for performing communication in a MIMO system, comprising: a channel estimator for calculating a channel-estimated value; a signal detector for calculating a bit log likelihood ratio of a transmitted signal from a received signal; and, a decoder for performing an error correction decoding process for the bit log likelihood ratio, wherein the signal detector includes: a transmitted signal candidate generator for generating transmitted signal candidates; a metric generator for generating metrics with regard to the transmitted signal candidates; and, a likelihood processor for determining the transmitted signal candidate producing the minimum metric among the metrics, as the maximum likelihood sequence and calculating the bit log likelihood ratio for the maximum likelihood sequence, the transmitted signal candidate generator includes: an initial signal generator for generating an initial signal; an updating value processor for determining an updating value for the initial signal; an adder for summing up the initial signal and the updating value; and a quantizer for performing a hard-decision of the sum from the adder to generate the transmitted signal candidates, and, the updating value processor includes: a search direction generator for calculating a direction in which reception performance degrades, at least based on the channel-estimated value; a step size generator for calculating a step size based on the initial signal and the direction in which the reception performance degrades; and, an updating value generator for calculating the updating value from the direction in which the reception performance degrades and the step size.