A method and apparatus for transferring information over a communications link includes transmitting information at a first power level, monitoring for correct reception of the transmitted information and transmitting further information at a second, power level other than that used for the original transmission if correct reception did not occur. The further information allows the content of the originally transmitted information to be established and in one embodiment constitutes a retransmission of the originally transmitted information. By retransmitting at a different power level the probability of correct reception may be enhanced, especially when the communications link is wireless. The first and second transmission power levels are governed using closed loop power control such that transmission power level is controlled to achieve a required quality of reception parameter at the receiving end of the link. In one arrangement the quality or reception parameter is the signal-to-interference ratio.
The present invention relates to a transmission power control apparatus and a radio base station that properly maintain a target value of uplink transmission quality as a reference for transmission power control. An object of the present invention is to accurately maintain a target value at a proper value at low cost. Thus, a transmission power control apparatus according to the present invention includes a monitor section which monitors a value of the uplink transmission quality; and a target value update section which updates the target value in such a manner as to decrease a difference between the value of the transmission quality monitored and the target value when the transmission quality is not in a predetermined range which includes the target value of the transmission quality as a reference.
An apparatus 300 for a cellular communication system (100) comprises a buffer (303) which receives data for transmission over an air interface (115). The buffer (303) is coupled to a scheduler (305) which schedules the data and allocates the physical resource of the air interface (115). The transmissions are performed using a retransmission scheme such as a Hybrid-Automatic Repeat reQuest scheme. A load processor (309) determines a load characteristic associated with the scheduler (305) and a target controller (311) sets a target parameter for the retransmission scheme in response to the load characteristic. Specifically, a block error rate target may be set in response to a load level of a cell or plurality of cells. A transmission controller (307) sets a transmission parameter for a transmission in response to the target parameter and a transmitter (301) transmits the data using the transmission parameter. Accordingly, an operating point of the retransmission scheme may be dynamically adjusted thereby reducing overall latency.
