Downlink scheduling and rate adaptation design of multi-user, multiple-antenna base station with imperfect CSIT

In this paper, we investigate the downlink scheduling and rate adaptation design in multiuser multiple-input single-output (MISO) systems with imperfect channel state information at the transmitter (CSIT). We shall propose a systematic design framework to address the multi-user scheduling and rate adaptation combined design based on information theoretical framework. We assume time division duplex (TDD) systems with quasi-static fading channels where packet outage is an important concern with imperfect CSIT. We introduce the average system goodput as the measure of system performance in the presence of CSIT error and effective albeit suboptimal solutions are proposed to maximize the average system goodput. Given any target outage probability /spl isin/, a Gaussian approximation on the outage probability is derived and the closed-form solution is obtained for the cross-layer scheduling design based on this approximation. Numerical results demonstrate that, by considering the statistic of CSIT errors into the design, the proposed schemes provide significant goodput enhancement.