Downlink MIMO Channel Estimation for Transmission Precoding

Transmission precoding in MIMO wireless systems can significantly improve system capacity and diversity gain. The effectiveness of MIMO precoding depends critically on accurate knowledge of channel state information available to the transmitter. In this paper we describe a novel method for the feedback of downlink channel estimation from an end user unit. Instead of letting the mobile receivers first identify and then send back the downlink channel parameters, a receiver returns portions of its received data back to the base station for channel identification. The base-station can then utilize all the channel information to design channel-aware downlink precoders. Simulation results are provided to illustrate the performance of the proposed methods.