| abstract |
A technique is disclosed for correcting downlink and uplink channels to identify differences in transmit and receive chains at access points and user terminals. In one embodiment, pilots are transmitted on the downlink and uplink channels and used to obtain estimates of the downlink and uplink channel responses, respectively. Then, two sets of correction factors are determined based on estimates of the downlink and uplink channel responses. A corrected downlink channel is generated using the first set of correction factors for the downlink channel, and a corrected uplink channel is generated using the second set of correction factors for the uplink channel. The first and second sets of correction factors can be determined using matrix-ratio calculations or minimum mean squared error (MMSE) calculations. Such correction can be performed in real time based on air transmission. |