A novel low-complexity user selection scheme for multiuser MIMO downlink with zero-forcing beamforming

This letter proposed a user selection with swap (USS) algorithm based on zero-forcing beamforming (ZFBF). USS starts with an initial user group with the largest channel 2-norms, iteratively swap the “worst” user (has the minimal achieved rate) among the scheduled users with the “best” user (has the maximum channel 2-norm) among the remaining users. Based on the simulation results, we can confirm that the proposed USS algorithm can provide a comparable performance with previous algorithms with greatly reduced complexity of O(KN2).