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In [[spatial correlation|spatially correlated]] environments, the long-term channel statistics can be combined with low-rate feedback to perform multi-user precoding.<ref>D. Hammarwall, M. Bengtsson, and B. Ottersten, [https://dx.doi.org/10.1109/TSP.2008.920484 Utilizing the spatial information provided by channel norm feedback in SDMA systems], IEEE Transactions on Signal Processing, vol. 56, no. 7, pp. 3278–3293, 2008</ref> As spatially correlated statistics contain much directional information, it is only necessary for users to feed back their current channel gain to achieve reasonable channel knowledge. As the beamforming weights are selected from the statistics, and not randomly, this approach outperforms random beamforming under strong spatial correlation.<ref>E. Björnson, D. Hammarwall, B. Ottersten, [http://kth.diva-portal.org/smash/get/diva2:402940/FULLTEXT01 Exploiting Quantized Channel Norm Feedback through Conditional Statistics in Arbitrarily Correlated MIMO Systems], IEEE Transactions on Signal Processing, vol. 57, no. 10, pp. 4027-4041, 2009</ref>
In multiuser MIMO systems where the number of users are higher than the number of transmit antennas, a multiuser diversity can be achieved by performing user scheduling before applying zero-forcing beamforming. Multiuser diversity is a form of selection diversity among users, the base station can schedule its transmission to those users with favorable channel fading conditions to improve the system throughput. In order to achieve multiuser diversity and apply zero-forcing precoding, the CSI of all users are required at the base station. However, the amount of overall feedback information increases with the number of users. Therefore, it is important to perform a user selection at the receiver
===DPC or DPC-like nonlinear precoding===
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