Patent ID: 8422942

Claim:
A radio relay apparatus for receiving signals from a transmitter via multiple receive antennas and transmitting relay signals derived from the received signals to a receiver via multiple transmit antennas, comprising: a channel estimation unit configured to estimate a forward channel matrix H 1 and a loop channel matrix G, the forward channel matrix H 1 representing radio channel characteristics between the transmitter and the radio relay apparatus, the loop channel matrix G representing interference occurring in the relay signals due to concurrently transmitting and receiving signals at the radio relay apparatus; a weight optimization unit configured to derive a canceling matrix C through iterative operations using the forward channel matrix H 1 , the loop channel matrix G and a backward channel matrix H 2 representing radio channel characteristics between the radio relay apparatus and the receiver; and a feedback compensation unit configured to subtract a signal weighted in accordance with the canceling matrix C in a feedback path from a relay signal in a main signal path to adjust the relay signal.