Periodic channel state information reporting for time division duplex (tdd) carrier aggregation systems

An apparatus of a user equipment (UE) operable to report periodic channel state information (CSI) to an eNodeB, the UE comprising:

• memory;
• and
• one or more processors configured to:
• determine, at the UE, a reporting period (Npd) of a serving cell of the UE;
• determine, at the UE, a Time-Division Duplex (TDD) uplink-downlink (UL-DL) configuration of a primary cell of the UE;
• and
• encode, at the UE, multiple periodic CSI reports for transmission to the eNodeB using a physical uplink control channel (PUCCH) on the primary cell according to the reporting period Npd, wherein:
• the reporting period Npd=1 is selected for the serving cell when the TDD UL-DL configuration of the primary cell is 0, 1, 3, 4, or 6 and all UL subframes of the primary cell in a radio frame are used for periodic CSI reporting;
• or
• the reporting period Npd=5 is selected for the serving cell when the TDD UL-DL configuration of the primary cell is 0, 1, 2, or 6;
• or
• the reporting period Npd=10, 20, 40, 80, or 160 is selected for the serving cell for all TDD UL-DL configurations of the primary cell.

At least one non-transitory computer readable medium having instructions embodied thereon for reporting periodic channel state information (CSI) from a user equipment (UE) to an eNodeB, the instructions when executed using one or more processors perform the following:

• determining, at the UE, a reporting period (Npd) of a serving cell of the UE;
• determining, at the UE, a Time-Division Duplex (TDD) uplink-downlink (UL-DL) configuration of a primary cell of the UE;
• and
• encoding, at the UE, multiple periodic CSI reports for transmission to the eNodeB using a physical uplink control channel (PUCCH) on the primary cell according to the reporting period Npd, wherein:
• the reporting period Npd=1 is selected for the serving cell when the TDD UL-DL configuration of the primary cell is 0, 1, 3, 4, or 6 and all UL subframes of the primary cell in a radio frame are used for periodic CSI reporting;
• or
• the reporting period Npd=5 is selected for the serving cell when the TDD UL-DL configuration of the primary cell is 0, 1, 2, or 6;
• or
• the reporting period Npd=10, 20, 40, 80, or 160 is selected for the serving cell for all TDD UL-DL configurations of the primary cell.