Patent ID: 8223895

Claim:
A signal demultiplexing method for determining a likelihood of each bit included in a first signal based on a maximum likelihood detection (MLD) method using QR decomposition, the first signal excluding a second signal to be calculated only in a final stage of the MLD method, wherein both the first and second signals are spatially multiplexed and received, the signal demultiplexing method comprising: for each of a plurality of signal point candidates of the first signal, detecting a closest neighboring signal point to thereby obtain a plurality of closest neighboring signal points, wherein each of the signal point candidates of the first signal is determined by one stage before the final stage, and each of the closest neighboring signal points is a point that is on a constellation of points in a signal space of the second signal and that has a smallest distance from a signal point calculated based on each of the signal point candidates of the first signal, respectively; calculating a distance from each of unitary-converted received signal points, to each of the plurality of signal point candidates of the first signal and to each of the plurality of closest neighboring signal points; and determining a likelihood of each bit included in the first signal by identifying a corresponding smallest value among the calculated distances.