US Patent 8005131 Delay compensation for transmit/receive chain calibration and multiuser MIMO

Compensation is provided for errors in channel information that can result when there is a delay between the measurement of the channel information and the subsequent use of the channel information. In one embodiment, downlink channel prediction is performed within a user device, in a system employing closed loop MIMO with implicit feedback, to reduce the occurrence of errors during the calculation of a calibration parameter within an associated base station. In another embodiment, channel prediction is used to predict a downlink channel state for a user device at a future time when a multi-user MIMO data transfer is to occur between a base station and a number of selected user devices.