Patent ID: 8903025

Claim:
A method of detecting data in a received multiple-input-multiple-output (MIMO) signal, the method comprising: receiving, via a transmission channel, a first signal (y1), a second signal (y2), and a third signal (y3) on first, second, and third spatial streams, respectively, wherein the received signals are associated with first data values (x1), second data values (x2), and third data values (x3); forming the first signal, the second signal, and the third signal into a received signal vector y; forming the first data values, the second data values, and the third data values into a vector x; receiving a channel matrix (H) representing effects of the transmission channel on the first data values, the second data values, and the third data values; performing a QR decomposition of the channel matrix, such that H=QR, wherein Q matrix is a unitary matrix and R matrix is an upper triangular matrix; transforming the received signal vector y into a rotated received signal vector z according to z=Q H y; determining a distance value between the vector z and the vector x for each possible third data value (x3), the determining including: calculating a nearest constellation point based on a first of the possible third data values (x3), wherein the nearest constellation point minimizes a distance between vector z and vector x, repeating the calculating step for each of the possible third data values (x3) to generate a set of constellation point triplets, wherein one constellation point triplet is associated with each of the possible third data values (x3), and determining a distance value between the vector z and the vector x using the set of constellation point triplets, and further using elements of the channel matrix, wherein one distance value is associated with each of the constellation point triplets of the set; and determining one or more log likelihood ratio (LLR) values based on the determined distance values.