A method comprising: obtaining information indicating channel conditions between a wireless network device and each of T client stations, where T is an integer greater than one, wherein the T client stations include (i) R client stations that are simultaneous downlink transmission enabled, and (ii) T-R legacy client stations that are not simultaneous downlink transmission enabled, where R is an integer less than or equal to T, receiving R independent data streams for the R client stations; modulating each of the R independent data streams to provide M modulated data streams to be received by each of R matrix modules, where R and M are integers greater than one; generating R multiplexing matrices via the R matrix modules for each of R client stations based on at least the channel conditions between the wireless network device and each of the R client stations including selecting values of the R multiplexing matrices such that for each of the R client stations results of multiplying a channel representation for the corresponding one of the R client stations by each of the R multiplexing matrices, other than the multiplexing matrix for the corresponding one of the R client stations, are equal to zero; for each of the R matrix modules, applying a corresponding one of the R multiplexing matrices to each of the corresponding ones of the M modulated data streams to generate M multiplexed data streams; summing portions of the M multiplexed data streams to generate M transmit data streams; and simultaneously transmitting the M transmit data streams to the R client stations and receiving R acknowledgements, ACKs, from the R client stations during a simultaneous downlink transmission, SDT, period, wherein the acknowledgements are received during respective R allocated time slots of the simultaneous downlink transmission period; prior to simultaneously transmitting the M transmit data streams to the R client stations, instructing the T-R client stations not to transmit during the simultaneous downlink transmission period or arranging with the T-R client stations the simultaneous downlink period, such that the T-R client stations do not transmit during the simultaneous downlink transmission period; and permitting the T-R client stations to transmit during a carrier sense multiple access window occurring at least one of prior to or subsequent to the simultaneous downlink transmission period. obtaining information indicating channel conditions between a wireless network device and each of T client stations, where T is an integer greater than one, wherein the T client stations include (i) R client stations that are simultaneous downlink transmission enabled, and (ii) T-R legacy client stations that are not simultaneous downlink transmission enabled, where R is an integer less than or equal to T, receiving R independent data streams for the R client stations; modulating each of the R independent data streams to provide M modulated data streams to be received by each of R matrix modules, where R and M are integers greater than one; generating R multiplexing matrices via the R matrix modules for each of R client stations based on at least the channel conditions between the wireless network device and each of the R client stations including selecting values of the R multiplexing matrices such that for each of the R client stations results of multiplying a channel representation for the corresponding one of the R client stations by each of the R multiplexing matrices, other than the multiplexing matrix for the corresponding one of the R client stations, are equal to zero; for each of the R matrix modules, applying a corresponding one of the R multiplexing matrices to each of the corresponding ones of the M modulated data streams to generate M multiplexed data streams; summing portions of the M multiplexed data streams to generate M transmit data streams; and simultaneously transmitting the M transmit data streams to the R client stations and receiving R acknowledgements, ACKs, from the R client stations during a simultaneous downlink transmission, SDT, period, wherein the acknowledgements are received during respective R allocated time slots of the simultaneous downlink transmission period; prior to simultaneously transmitting the M transmit data streams to the R client stations, instructing the T-R client stations not to transmit during the simultaneous downlink transmission period or arranging with the T-R client stations the simultaneous downlink period, such that the T-R client stations do not transmit during the simultaneous downlink transmission period; and permitting the T-R client stations to transmit during a carrier sense multiple access window occurring at least one of prior to or subsequent to the simultaneous downlink transmission period.