An Enhanced Algorithm for the Transmission Mode Switching in TD-LTE Downlink Systems

摘要

Downlink beamforming is an efficient technique in TD-LTE systems to provide the diversity or multiplexing gains when suitable antenna mode switching algorithm is applied. Since the radio channel information is not perfectly obtained at the transmitter, the antenna mode decided by the base station (BS) is not often suitable, and the cell throughput decreases especially when the user equipment (UE) with high speed mobility and there is a large feedback delay. To solve this problem, a dynamic antenna mode switching (DAMS) algorithm is proposed for the downlink transmission in TD-LTE systems, where a cell-specific offset and a UE-specific offset are utilized to adjust the channel quality indicator (CQI) fed back from UE and determine the suitable antenna mode. According to the simulation results, compared with the conventional mode switching (CMS) algorithm, the proposed DAMS algorithm enhances both the cell spectrum efficiency and the initial transmission success ratio (ITSR) dramatically.