Adaptive Narrowband Interference Canceller for Broadband Systems
First Claim
1. An adaptive interference canceller for a broadband communication system comprising:
- a first signal path for carrying a received broadband signal including a broadband communication signal said broadband communication signal having a correlation time associated therewith;
an interference cancellation loop comprising;
a delay element having a delay time associated therewith for delaying said received broadband signal and producing a delayed signal, said delayed signal being a delayed version of said received broadband signal;
a signal multiplier having a weight value associated therewith for receiving said delayed signal and producing a weighted delayed signal;
an adaptive element for adjusting said weight value;
an adder for adding said received broadband signal and said weighted delayed signal to produce an interference reduced output signal;
wherein said delay time is longer than the correlation time of said broadband communication signal.
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Accused Products
Abstract
An interference canceller for canceling narrowband interference from a received broadband signal takes advantage of the fact that the correlation time for the narrowband interference signal will be significantly greater than the correlation time for the desirable broadband signal. The interference canceller operates by creating a replica of the narrowband interference signal in an auixiliary channel and subtracts it from the main channel to cancel the interference. The auxiliary channel has a delay time larger than the correlation time of the desirable broadband signal. In-phase and quadrature versions of the delayed signal are multiplied by respective weights and subtracted from the received signal to produce an interference-reduced signal. The weights are are adjusted by an adaptive block to minimize the power in the interference-reduced output signal.
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Citations
20 Claims
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1. An adaptive interference canceller for a broadband communication system comprising:
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a first signal path for carrying a received broadband signal including a broadband communication signal said broadband communication signal having a correlation time associated therewith;
an interference cancellation loop comprising;
a delay element having a delay time associated therewith for delaying said received broadband signal and producing a delayed signal, said delayed signal being a delayed version of said received broadband signal;
a signal multiplier having a weight value associated therewith for receiving said delayed signal and producing a weighted delayed signal;
an adaptive element for adjusting said weight value;
an adder for adding said received broadband signal and said weighted delayed signal to produce an interference reduced output signal;
wherein said delay time is longer than the correlation time of said broadband communication signal. - View Dependent Claims (2, 3)
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4. A method of canceling narrowband interference from a broadband channel, the broadband channel carrying a received broadband signal having a broadband information signal and narrowband interference, the broadband information signal having a correlation time associated therewith, the method comprising:
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delaying the received broadband signal by a delay time greater than the correlation time of the broadband information signal to produce a delayed signal;
producing a quadrature version of the delayed signal, said quadrature version being phase shifted by approximately 90 degrees from the delayed signal;
multiplying the delayed signal by a first factor to produce a weighted delayed signal;
multiplying the quadrature version of the delayed signal by a second factor to produce a weighted quadrature delayed signal;
adding the weighted delayed signal and the weighted quadrature delayed signal to the received broadband signal to produce an interference-reduced version of said received broadband signal;
whereby said narrowband interference is at least partially cancelled from said received broadband signal. - View Dependent Claims (5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
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17. An adaptive interference canceller comprising:
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a first signal path for carrying a first signal, said first signal having a correlation time associated therewith;
a interface cancellation loop comprising;
a delay element having a delay time associated therewith for delaying said first signal and producing a delayed first signal;
a first multiplier having a first weight value associated therewith for receiving said delayed signal and producing a weighted delayed signal;
a first adaptive element for adjusting said first weight value;
an adder for adding said first signal and said weighted delayed signal to produce an interference reduced output signal;
wherein said delay time is longer than the correlation time of said first signal. - View Dependent Claims (18, 19, 20)
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Specification