Patent ID: 8139677

Claim:
A method for determining K rotation angles for rotating a set of K input data symbols to be applied to a block code that encodes the resulting set of K rotated data symbols, the method comprising: (a) selecting a first rotation angle for a first subset of the K rotation angles; (b) for each combination of (i) each of a plurality of different possible second rotation angles for a second subset of the K rotation angles, (ii) each of a plurality of different possible codewords for the first rotation angle and each possible second rotation angle, and (iii) each of a plurality of different possible erroneously decoded codewords for each possible codeword, generating a metric for said each combination; (c) selecting a second rotation angle for the second subset of the K rotation angles based on the metrics of step (b); and (d) providing a transmitter configured based on the selected first and second rotation angles, wherein, for each set of K input data symbols, the transmitter is adapted to: (1) rotate the first subset of the K input data symbols based on the selected first rotation angle; (2) rotate the second subset of the K input data symbols based on the selected second rotation angle; and (3) apply the block code to the resulting set of K rotated data symbols to generate an outgoing codeword for transmission from the transmitter, wherein the block code is a space-frequency block code.