Patent ID: 7978779

Claim:
A Multiple Input Multiple Output (MIMO) Orthogonal Frequency Division Multiplexing (OFDM) system employing N T transmit antennas and N R receive antennas for data transmission wherein N T and N R are each an integer greater than 1, the MIMO OFDM system comprising a MIMO OFDM receiver comprising: multicarrier demodulators for demodulating received signals passed through a MIMO channel formed by the transmit and receive antennas, wherein the received signals are interleaved by using a symbol block of Nr constellation symbols as its basic unit; a tone-level deinterleaver for deinterleaving the received signals after demodulation and for outputting deinterleaved symbol blocks; and a channel decoder for decoding the deinterleaved symbol blocks, wherein the channel decoder is a Viterbi decoder, wherein the Viterbi decoder comprises: a List Sphere Decoding (LSD) unit for using an LSD algorithm to obtain a candidate path list including candidate paths; a suboptimal branch metrics calculation unit for calculating branch metrics belonging to paths beginning from the subset of beginning states with the greatest state metrics within the candidate path list according to the deinterleaved symbol blocks and the estimated MIMO channel; an add-compare-select (ACS) unit for performing an ACS operation according to the branch metrics; and a survivor path decoding unit for decoding a survived path with maximum likelihood provided by the ACS operation.