Patent ID: 8542781

Claim:
A method of operating a receiver which receives a signal over a radio interface, comprising of: (1) receiving, over a radio channel, a frequency-domain signal that comprises contribution from time-domain symbols transmitted from one or more transmit antennas; (2) generating a transformation matrix and a triangular matrix based on a frequency domain channel response of the radio channel; (3) using the transformation matrix to transform the received frequency-domain signal to obtain a transformed frequency-domain signal; (4) performing symbol detection based on the triangular matrix by performing plural detection stages, each detection stage using elements of the transformed frequency-domain signal associated with that detection stage, the plural detection stages comprising: (4a) in a first detection stage: forming hypotheses for the first detection stage based on possible modulation values of one of the time-domain symbols, evaluating detection metrics for all the hypotheses formed for the first detection stage, and in accordance with the evaluation of the detection metrics, retaining a predetermined number of best hypotheses from the first detection stage, (4b) in an intermediate detection stage: jointly detecting a number of time-domain symbols, the detected time-domain symbols including all the time-domain symbols that were jointly detected in an immediately preceding stage and an additional time-domain symbol that was not detected in any previous stages; forming joint hypotheses for the intermediate stage based on possible modulation values used by the additional time-domain symbol and retained joint hypotheses for the time-domain symbols that were jointly detected in the immediately preceding stage; evaluating detection metrics for all the hypotheses formed for the intermediate stage, and in accordance with the evaluation of the detection metrics of said intermediate stage, retaining a predetermined number of best hypotheses from the intermediated stage (4c) in a last detection stage, jointly detecting all the time-domain symbols.