Downlink transmission method and a base station in a multiple input multiple output system

To provide a downlink transmission method in a multiple-input multiple-output system. The method includes the steps of generating and generating a channel status indication value to get the channel quality indication information of the user equipment UE, the channel correlation indicated value to obtain channel rank information of UE, selecting a step to acquire an uplink channel impulse response estimate data of the UE generates the channel change status indication value, the channel status indication value, a downlink transmission mode according to a channel correlation indicator value and channel fluctuation status indication value comprising a step, and transmitting the data in the selected downlink transmission mode to the UE. Thus greatly improves the resource utilization of the system, it is possible to realize a radio transmission effects. .The