A method for transmitting a CSI feedback report to a serving cell comprises for time division duplex, configuring at least one periodic CSI process with a CSI reference source defined by a single downlink subframe n−nCQI_ref, wherein nCQI_ref is a smallest value greater than or equal to a positive integer nCQI_ref_min, such that it corresponds to a valid downlink subframe, wherein nCQI_ref_min varies based on a number of at least one periodic CSI process. A method for CSI feedback reporting to a base station comprises configuring not to accommodate, by a user equipment, the one or more aperiodic CSI requests arrived from a serving cell except a CSI request of CSI processes with lower indexes for each serving cell, wherein a number of the one or more CSI processes with a lower index (es) is determined based on a number of pending CSI reports.