Patent ID: 8285201

Claim:
A wireless repeater having a first antenna and a second antenna to receive an input signal and transmit an amplified signal, the input signal being a sum of a remote signal to be repeated and a feedback signal resulting from a feedback channel between the first antenna and the second antenna, the repeater comprising: a first front-end circuit configured to couple to the receiving antenna of the first antenna and the second antenna to receive the input signal and including receive and transmit front-end processing circuitry; a second front-end circuit configured to couple to the transmitting antenna of the first antenna and the second antenna and configured to generate the amplified signal and including receive and transmit front-end processing circuitry; a repeater baseband block coupled between the first and second front-end circuits, the repeater baseband block to receive a processed input signal from the first front-end circuit and generate an output signal to be processed by the second front-end circuit, the repeater baseband block comprising: a channel estimation block to receive the processed input signal and estimate the feedback channel to provide a feedback channel estimate using frequency domain channel estimation; an echo canceller to receive the feedback channel estimation from the channel estimation block and to generate a feedback signal estimate based on the feedback channel estimate and further configured to cancel the feedback signal estimate from the input signal using time domain echo cancellation; a variable gain stage to amplify the echo cancelled signal to generate the output signal of the repeater baseband block; a gain control block to adjust the gain of the variable gain stage using digital gain control to increase repeater stability; a first variable delay element to introduce a first delay before or after the echo canceller, wherein the output of the first variable delay element and the echo canceller is provided as a delayed echo cancelled signal to the variable gain stage, the first delay being selected to provide decorrelation of the remote signal with the amplified signal, the first delay less than a maximum decorrelation delay amount; and a second variable delay element introducing a second delay to the output signal, the second delay being selected to reduce delay spread, the delayed output signal to be coupled to the channel estimation block as a reference signal to estimate the feedback channel, to the echo canceller as a reference signal to estimate the feedback signal, and to the gain control block to monitor the stability of the repeater.