Method and apparatus for interference cancellation and detection using precoders

An apparatus to achieve full diversity without sacrificing bandwidth and with a linear complexity in a wireless system comprising

• a plurality of orthogonally transmitting users each having N transmit antennas;
• at least one receiver having M receive antennas communicating with the plurality of transmitting users, which receiver separates the signals using the orthogonality of the transmitted signals, and decodes the signals independently to provide diversity of NM to the users;
• a plurality of precoders corresponding to the plurality of transmitting users, which precoders are designed using the channel information to cancel interference among the plurality of signals while achieving a maximum possible diversity of NM;
• and
• where the plurality of transmitting users orthogonally transmit a plurality of signals using the corresponding plurality of precoders in a plurality of time slots and where the plurality of transmitting users orthogonally transmit a plurality of signals utilizing multiple antennas using a corresponding plurality of precoders by determining for each time slot of transmission an equivalent channel equation characterized by a channel matrix {tilde over (H)} and a noise vector n for the users, generating an orthogonal structure of signal vectors in corresponding precoders for the users by utilizing a quasi-orthogonal design comprised of a subspace 1 created by the first two columns of matrix {tilde over (H)} orthogonal to a subspace 2 created by the second two columns of matrix H.

Signal processing instructions recorded within memory components of a communication system for controlling a plurality of orthogonally transmitting users each having N transmit antennas, at least one receiver having M receive antennas communicating with the plurality of transmitting users, which receiver separates the signals using the orthogonality of the transmitted signals, and decodes the signals independently to provide diversity of NM to the users, a plurality of precoders corresponding to the plurality of transmitting users, which precoders are designed using the channel information to cancel interference among the plurality of signals while achieving a diversity of NM, where the plurality of transmitting users orthogonally transmit a plurality of signals using the corresponding plurality of precoders in a plurality of time slots, and where the plurality of transmitting users orthogonally transmit a plurality of signals utilizing multiple antennas using a corresponding plurality of precoders by determining for each time slot of transmission an equivalent channel equation characterized by a channel matrix {tilde over (H)} and a noise vector n for the users, generating an orthogonal structure of signal vectors in corresponding precoders for the users by utilizing a quasi-orthogonal design comprised of a subspace 1 created by the first two columns of matrix {tilde over (H)} orthogonal to a subspace 2 created by the second two columns of matrix {tilde over (H)}.