Patent ID: 7400896

Claim:
An apparatus for adaptively performing transmission according to a state of a channel transmitted from a transmitter to at least one receiver, comprising: a signal to interference ratio estimator for despreading signals, spread by the unique code of the receiver from the at least one receiver, using the unique code, measuring a multipath profile represented a delay time and signal strength of downlink signal transmitted through the multipath between the transmitter and the receiver from the despreading signals, transforming a multipath profile according to the FFT and acquiring a channel transfer function, estimating a distance between the transmitter and the receiver according to the delay time and estimating interference power between the transmitter and the receiver according to the distance, and estimating a signal to interference ratio of the subchannels of the receiver using a ratio of a the signal FFT processed and the estimated interference power; and an adaptive transmitter for transmitting data to the at least one receiver based on the estimated signal to interference ratio.