A Two-Step User Selection Algorithm for Multiuser Precoding

A two-step user selection algorithm for multiuser precoding based on the minimum-mean-square error criterion is proposed in this paper. The first step is the sequential user selection algorithm, where the focus is on minimizing the increase in the mean square error (MSE) when adding a new user to the service user set. During the first step, previous selection results can be used in the subsequent operation to reduce the computational complexity of the algorithm. In the second step, the user index regeneration algorithm is performed to further lower the MSE. Analysis and simulation results show that the proposed two-step user selection algorithm has better performance and lower complexity than the existing iterative algorithm. Compared with the decremental algorithm, the proposed algorithm has marginal performance loss with much lower computational complexity. The given advantages are also verified in a scenario with channel estimation errors. In a round-robin scheme, where all the available users are scheduled, the simulation result shows that the capacity of the proposed two-step algorithm is a little higher than that of the decremental algorithm.