Method and apparatus for obtaining channel state information

The invention discloses a method for obtaining channel state information. The method comprises the following steps: selecting a first type precoding matrix index PMI for each layer, and selecting an optimal second type PMI for each layer according to a preset criterion on the basis of the first type PMI of each layer and a second type PMI set; selecting an optimal first type PMI for each layer according to a preset criterion on the basis of the optimal second type PMI of each layer and a first type PMI set; selecting a first type PMI and a second type PMI in best match with a current channel from the optimal first type PMIs and the optimal second type PMIs of all the layers according to a preset criterion, and using a layer number corresponding to the best matched first type PMI and the best matched second type PMI as a rank indicator RI of a channel matrix. The invention further discloses an apparatus for obtaining channel state information at the same time. 本发明公开了种信道状态信息获取方法，该方法包括：为每层选择第类预编码码本索引PMI，并根据每层的第类