Patent ID: 8737911

Claim:
A wireless repeater having a first antenna and a second antenna, the repeater comprising: a pilot insertion unit configured to generate a pilot signal, the pilot signal to be added to a transmit signal for transmission as a composite transmit signal; a first echo canceller to receive a receive signal and the transmit signal and generate a first echo cancelled signal using a currently available feedback channel estimate, the receive signal being the sum of a remote signal to be amplified, a feedback pilot signal and a feedback transmit signal, the feedback pilot signal and the feedback transmit signal being feedback signals fed back on a feedback channel between the first antenna and the second antenna, the first echo canceller configured to use the currently available feedback channel estimate to remove the feedback transmit signal from the receive signal; a channel estimation block to receive the first echo cancelled signal and also to receive the pilot signal as a reference signal, the channel estimation block configured to generate an updated feedback channel estimate based on the first echo cancelled signal and the reference signal; a second echo canceller to receive the receive signal, the pilot signal and the transmit signal and to generate a second echo cancelled signal using the updated feedback channel estimate, the second echo canceller configured to use the updated feedback channel estimate to remove the feedback transmit signal and the feedback pilot signal from the receive signal, and to thereby generate a second echo cancelled signal indicative of the remote signal; and an amplifier to amplify the second echo cancelled signal as the transmit signal, wherein the repeater is configured to add the pilot signal to the transmit signal to be transmitted as the composite transmit signal.