DELAY CONTROL TO IMPROVE FREQUENCY DOMAIN CHANNEL ESTIMATION IN AN ECHO CANCELLATION REPEATER
First Claim
1. A wireless repeater including 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:
- an echo canceller to receive the input signal and configured to generate an echo cancelled signal by estimating a feedback channel between the first antenna and the second antenna and further configured to cancel a feedback signal estimate from the input signal;
an amplifier to amplify the echo cancelled signal and to provide the amplified signal to the first antenna or the second antenna to be transmitted; and
a variable delay element configured to receive the echo cancelled signal and to introduce a first delay to the echo cancelled signal, the first delay being selected to reduce delay spread in the estimation of the feedback channel, wherein the delayed echo cancelled signal output by the variable delay element is coupled to the echo canceller as a reference signal for estimating the feedback channel.
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Accused Products
Abstract
A wireless repeater has a receiving antenna for receiving an input signal and a transmitting antenna for transmitting an amplified signal where the input signal is a sum of a remote signal and a feedback signal. The repeater includes an echo canceller receiving the input signal and generating an echo cancelled signal by estimating a feedback channel between the transmitting antenna and the receiving antenna and cancelling a feedback signal estimate from the input signal, an amplifier for amplifying the echo cancelled signal and providing the amplified signal to the transmitting antenna, and a variable delay element receiving the echo cancelled signal and introducing a first delay to the echo cancelled signal. The first delay is selected to optimize the estimation of the feedback channel, thereby optimizing the cancellation of the feedback signal. The delayed echo cancelled signal is coupled to the echo canceller as a reference signal for estimating the feedback channel.
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Citations
14 Claims
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1. A wireless repeater including 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:
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an echo canceller to receive the input signal and configured to generate an echo cancelled signal by estimating a feedback channel between the first antenna and the second antenna and further configured to cancel a feedback signal estimate from the input signal; an amplifier to amplify the echo cancelled signal and to provide the amplified signal to the first antenna or the second antenna to be transmitted; and a variable delay element configured to receive the echo cancelled signal and to introduce a first delay to the echo cancelled signal, the first delay being selected to reduce delay spread in the estimation of the feedback channel, wherein the delayed echo cancelled signal output by the variable delay element is coupled to the echo canceller as a reference signal for estimating the feedback channel. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A wireless repeater having a first antenna and a second antenna for receiving an input signal and for transmitting 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:
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means for receiving the input signal and generating an echo cancelled signal by estimating a feedback channel between the first antenna and the second antenna and cancelling a feedback signal estimate from the input signal; means for amplifying the echo cancelled signal and providing the amplified signal to the transmitting antenna; and means for introducing a first delay to the echo cancelled signal, the first delay being selected to reduce delay spread in the estimation of the feedback channel, the delayed echo cancelled signal being coupled to the echo canceller as a reference signal for estimating the feedback channel.
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9. A method for providing echo cancellation in a wireless repeater in a wireless communication system, comprising:
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receiving an input signal at a first antenna of the repeater, 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 a second antenna; estimating a feedback channel between the first antenna and the second antenna of the repeater; cancelling a feedback signal estimate from the input signal and generating an echo cancelled signal; amplifying the echo cancelled signal; transmitting the amplified signal on the transmitting antenna; introducing a first delay to the echo cancelled signal, the first delay being selected to reduce delay spread in the estimation of the feedback channel; and providing the delayed echo cancelled signal as a reference signal for estimating the feedback channel, the reference signal being delayed from the amplified signal and having the effect of advancing the feedback channel to be estimated. - View Dependent Claims (10, 11, 12, 13, 14)
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Specification