If at least one user survives the CTS contention phase, the next stage of downlink data transmission can take place. Users which successfully passed the CTS phase are candidates for downlink data transmission. The AP chooses the set of n users with the best SNIR values, and assigns them to each beam (maximum one user per beam). The transmission rate on each beam is adapted for the selected user SNR value, resulting to a transmission time of T · In the last phase users acknowledge the received downlink packets by sequentially sending an ACK to the AP.