Joint Transmission Mode Selection and Scheduling in LTE Downlink MIMO Systems

In this article, we investigate multiple-input multiple-output (MIMO) transmission mode selection and scheduling for LTE downlink with users of different mobilities. Our algorithm first classifies users into high- and low-mobility ones, then selects open-loop spatial multiplexing (OLSM) or close-loop spatial multiplexing (CLSM) mode based on user's mobility, and finally assigns the time-frequency resources to ensure multi-user or frequency diversity. The proposed algorithm is with low complexity, considers all practical constraints in LTE systems, and can achieve up to 27% cell-average and 25% cell-edge throughput gain.