Patent ID: 7813272

Claim:
A data transmission system for exchanging packets each including a data channel, comprising: a transmitting station including a controller for controlling packet communication quality in accordance with a channel quality indicator (CQI) indicative of quality of a packet propagation path so that the packet communication quality may become highest, a packet generator for generating a packet, and a first transmitter for transmitting the packet; and a receiving station including a receiver for receiving the packet, a format changer for changing a CQI format that specifies how many bits to use to represent CQI information in each feedback to the transmitting station, in accordance with communication quality of the received packet with respect to a threshold thereof, a measuring unit for measuring the CQI based on the CQI format, and a second transmitter for transmitting the measured CQI to the transmitting station; wherein the receiving station adjusts the threshold of the communication quality for changing the CQI format, in accordance with a state of occupancy of the propagation path from the receiving station to the transmitting station notified from the transmitting station via a downlink control channel.