Transmit Power Control for Pilot-based CQI Reporting in OFDMA/TDD Systems

This paper proposes transmit power control (TPC) for pilot-based channel quality indicator (CQI) reporting in OFDMA/TDD systems. In the proposed TPC scheme, the terminal controls transmit power of pilot signals for CQI reporting, such that the base station (BS) can receive the pilot signals with higher power than the BS´s interference-plus-noise power. In the proposed TPC scheme, the terminal determines appropriate transmit power using downlink pilot signals. The numerical results show that uplink signalling for CQI reporting can be effectively reduced by updating transmit power level in longer period than period of pilot signal transmission. Using appropriate period of updating the transmit power, the terminal can report one unit of CQI using a small number of uplink symbols, e.g. 1.5 symbols, keeping accuracy of CQI reporting.