Patent ID: 7965782

Claim:
A method for a demodulator, the method for generating and selecting a minimum distance metric for a plurality of n streams of incoming symbol data, where n is an integer and said n streams of symbol data are associated with a channel characterization H matrix having n columns, the method comprising: a stream ordering transformation generating step where for each symbol y m of an m th one of said n streams of incoming data, and where said m is in the range m=1 to m=n: said channel characterization H matrix is transformed into an m th stream-specific column-swapped H m ′ matrix by swapping the m th column elements with the first column elements of said H matrix, said m th stream-specific column-swapped H m ′ matrix thereafter being transformed into a stream-specific Q m ′ matrix and a stream-specific upper triangular R m ′ matrix, the stream-specific Q m ′ matrix and stream-specific upper triangular R m ′ matrix having the property that said Q m ′ matrix multiplied by said upper triangular R m ′ matrix equals said stream-specific H m ′ matrix, and said upper triangular R m ′ matrix has all elements below a main diagonal with a value of zero, said transformation also computing for each said Q m ′ matrix a Hermitian matrix Q m ′ H ; forming a table of entries for said y m having: a z m symbol formed by multiplying said y m symbol by the corresponding said Q m ′ H matrix for that particular stream accompanied by all possible values of x m for the other streams and computing a distance metric to a received symbol for each said entry; a z m ′ symbol formed by multiplying said y m symbol by the corresponding said Q m ′ H matrix for that particular stream accompanied by all possible values of x m for the other streams and computing a distance metric to a received symbol for each said entry; a minimum metric selecting step of selecting an entry with a minimum distance metric from said table of entries as a most likely candidate.