Technology for a user equipment (UE) operable to report periodic channel state information (CSI) is disclosed. The UE can determine a reporting period (Npd) of the UE for a serving cell. The UE can identify a Time-Division Duplex (TDD) uplink-downlink (UL-DL) configuration of a primary cell of the UE. The UE can transmit a periodic CSI report for the serving cell to an evolved node B (eNB) using a physical uplink control channel (PUCCH) on the primary cell according to the reporting period. The UE can use the reporting period of Npd=1 for the serving cell if the TDD UL-DL configuration of the primary cell is one of 0, 1, 3, 4, or 6 and all UL subframes of the primary cell in a radio frame are used for periodic CSI reporting.