Successive User Scheduling Schemes for a Multiuser MIMO System Employing Generalized Channel Inversion

Generalized channel inversion (GCI) is a precoding technique for multiuser multiple-input multiple-output system. While producing each user’s precoding matrix, GCI takes into account noise and thus it is more robust compared with alternative techniques such as block diagonalization technique in terms of sum rate capacity and frame error rate. In this paper, two suboptimal multiuser scheduling schemes for GCI are proposed that by scheduling a subset of mobile users nearly maximize the sum rate capacity. They employ an iterative approach involving a number of search steps. At each step, unselected mobile users are evaluated one by one, and only one of them is chosen according to given criteria. It is shown via computer simulations that the proposed schemes are capable of achieving a large portion of the sum rate capacity that is offered by an exhaustive search. The performance of the proposed multiuser scheduling schemes is evaluated when the antenna mutual coupling effects are taken into account at the mobile users’ sides. Numerical results reveal that the presence of antenna mutual coupling can result in an increased sum rate capacity when the array inter-element spacing is in the range of 0.3–0.4 wavelength.