Patent ID: 7599666

Claim:
An apparatus comprising: a receiver configured to receive a feedback signal transmitted from a receiving device; and a processor configured to process feedback information received from the receiving device during a certain time period, the feedback information including the feedback signal and previous feedback signals received from the receiving device, determine transmit weights to be applied to transmission signals to be transmitted from the transmitting device to the receiving device in accordance with the feedback information, and select a feedback mode and a corresponding feedback word length on the basis of the feedback information, wherein the feedback signal comprises a feedback word which is to be generated by the receiving device according to the feedback mode selected by the transmitting device, wherein the processor is configured to control the corresponding feedback word length in accordance with temporal properties of a channel between the transmitting device and the receiving device by comparing previous feedback words and detecting the change in the feedback words of same length and selecting the corresponding feedback word length in accordance with the detected change in the feedback words.