Method and apparatus for transmitting and receiving feedback on channel state information

A method of transmitting a channel state information (CSI) report by a user equipment (UE) in a wireless communication system, the method comprising:

• receiving, from a base station (BS) via radio resource control (RRC) signaling, information for configuring at least one secondary cell (SCell) in addition to a primary cell (PCell) and a plurality of periodic CSI feedback configurations for a plurality of serving cells including the SCell and the PCell;
• and
• transmitting, to the BS via a subframe of the PCell, a CSI report for only one of the plurality of serving cells,
• wherein when CSI reports of two or more serving cells of the plurality of serving cells collide with each other in the subframe, one or more CSI reports having lower priorities are dropped, and
• wherein when CSI reports of different serving cells having a same priority collide with each other in the subframe, CSI reports of one or more serving cells other than one serving cell having a lowest cell index are dropped.

A base station (BS) comprising:

• a transmitter configured to transmit, to a user equipment (UE) via radio resource control (RRC) signaling, information for configuring at least one secondary cell (SCell) in addition to a primary cell (PCell) and a plurality of periodic channel state information (CSI) feedback configurations for a plurality of serving cells including the SCell and the PCell;
• a receiver configured to receive, from the UE via a subframe of the PCell, a CSI report for only one of the plurality of serving cells;
• and
• a processor configured to control the transmitter and the receiver,
• wherein when CSI reports of two or more serving cells of the plurality of serving cells collide with each other in the subframe, one or more CSI reports having lower priorities are dropped, and
• wherein when CSI reports of different serving cells having a same priority collide with each other in the subframe, CSI reports of one or more serving cells other than one serving cell having a lowest cell index are dropped.

A user equipment (UE) comprising:

• a receiver configured to receive, from a base station (BS) via radio resource control (RRC) signaling, information for configuring at least one secondary cell (SCell) in addition to a primary cell (PCell) and a plurality of periodic channel state information (CSI) feedback configurations for a plurality of serving cells including the SCell and the PCell;
• a transmitter configured to transmit, to the BS via a subframe of the PCell, a CSI report for only one of the plurality of serving cells;
• and
• a processor configured to control the receiver and the processor,
• wherein when CSI reports of two or more serving cells of the plurality of serving cells collide with each other in the subframe, one or more CSI reports having lower priorities are dropped, and
• wherein when CSI reports of different serving cells having a same priority collide with each other in the subframe, CSI reports of one or more serving cells other than one serving cell having a lowest cell index are dropped.