Research on TD-LTE Downlink MIMO Mode Selection and Switching Technology

Long Term Evolution (LTE) is an emerging 4G wireless access technology. Multiple Input Multiple Output (MIMO) systems can satisfy the needs of the LTE in high data rates, high transmission quality and high system capacity. In 3GPP eight different transmission modes are supported by the LTE downlink MIMO system. Base Station (eNodeB) is expected to select and switch transmission characteristics of these MIMO modes based on channel quality feedbacks: Channel Quality Indicator (CQI), Precoding Matrix Indicator (PMI) and Rank Indicator (RI) reported by the mobile. Therefore choosing a better algorithm can make a better feedback. Then through the simulation we can get the threshold of switching. By application different transmission modes in different environment or situations, the system could achieve the best transmission effect.