Patent ID: 8184737

Claim:
An echo cancellation and echo channel estimation system for relay using multiple antennas, the relay relaying signals between a transmitter and a receiver, the echo cancellation and echo channel estimation system comprising: a receive antenna for receiving a transmit signal from the transmitter and an echo signal via an echo channel; a preprocessing vector generation module for generating a preprocessing vector and applying the preprocessing vector, the transmit signal and the echo signal, received from the receive antenna, to an echo cancellation module, wherein the preprocessing vector is generated using the following equation: v =Null( h T E ), where Null( ) of the preprocessing vector is a function for obtaining a nulling vector, which is composed of a basis vector of an echo channel vector h T E in null space, and the nulling vector vεC N T×1 has a characteristic shown in the following equation: h T E v= 0; the echo cancellation module for canceling the echo signal by multiplying the preprocessing vector, the transmit signal, and the echo signal; and a transmit array antenna for receiving a retransmit signal from the echo cancellation module and resending the retransmit signal to the receiver.