Patent ID: 7515659

Claim:
A wireless device for a wireless data communication system comprising the wireless device and a base station, wherein the base station comprises a plurality of first groups, each first group comprising a receiver and at least one antenna connected to the receiver, and a signal-processing unit comprising memory and a processor adapted to process signals received by the first groups using a Maximum Likelihood Detection (MLD) method, and the wireless device comprising: a plurality of second groups, wherein: each second group is adapted to transmit a wireless signal to at least one first group via a corresponding communication channel; and each second group comprises a transmitter and at least one antenna connected to the transmitter; the signal-processing unit is adapted to store, in the memory, information corresponding to one or more transfer functions, each transfer function corresponding to transmission of a wireless signal from an antenna of the second groups to an antenna of the first groups; the transmitters and receivers are adapted to operate at essentially the same frequency or frequency band; two or more of the communication channels are generated simultaneously; each transmitter is adapted to modulate an information signal on a radio-frequency signal according to a Quadrature Amplitude Modulation (QAM) method to transmit QAM symbols; each receiver is adapted to demodulate information signals from a received radio-frequency signal according to the QAM method; and for the MLD method, the signal-processing unit is adapted to: (a) calculate a first vector length for each of a plurality of complex vectors corresponding to a constellation having a plurality of combinations of possible data values; and (b) select a subset of the combinations based on the first vector lengths calculated in step (a).