Performance Evaluation of Spatial Mode Adaptation and HARQ in Cellular Downlink Systems

System level simulations in a realistic multi-cell model are needed to evaluate the performance of the adaptive radio link and radio resource management (RRM) algorithms for future wireless communication systems. In this paper, we consider spatial mode adaptation, modulation adaptation, hybrid automatic repeat request (HARQ) and scheduling in a cellular network. In order to simulate a considered multiple-input multiple-output (MIMO) orthogonal frequency division multiplexing (OFDM) physical layer, a novel link frame error rate (FER) prediction method is presented. Link-to-system level method is based on the mutual information metric which takes multiple antenna receiver and multiple antenna channel coding into account. The proposed metric is shown to provide an accurate FER approximation for diverse range of MIMO-OFDM channels also with inter-cell interference and HARQ. System level results illustrate that the MIMO-OFDM system with adaptive space-frequency turbo coded modulation (SFTuCM) provides flexibility and high spectral efficiency for interference limited system. The MIMO-OFDM system with interference averaging frequency hopping channel allocation achieves performance close to the channel condition aware dynamic channel allocation (DCA) with time division multiple access (TDMA).