All-analog and hybrid radio interference cancellation using cables, attenuators and power splitters
First Claim
1. A radio interference cancelation device that cancels self-interference from a transmitter to a receiver, the system comprising:
- a 2N-way RF power splitter having an input and 2N outputs, wherein N is an integer;
a power combiner having 2N+1 inputs and an output; and
2N adaptively controllable attenuators, each adaptively controllable attenuator coupled by cables between a different output of the 2N-way RF power splitter and a different input of the power combiner, each cable having a total length selected to provide a delay equal to a different one of mT(m=1,N) and mT+δ
(m=1,N), where T is a delay smaller than the inverse of a bandwidth of the transmitter and receiver, and δ
is ¼
fc, where fc is the carrier frequency of an RF signal transmitted by the transmitter.
1 Assignment
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Accused Products
Abstract
A radio interference cancellation device that cancels self-interference from a transmitter to a receiver that includes a 2N-way RF power splitter having an input and 2N outputs, a power combiner having 2N+1 inputs and an output, and 2N adaptively controllable attenuators. Each adaptively controllable attenuator is coupled by cables between a different output of the 2N-way RF power splitter and a different input of the power combiner, each cable having a total length selected to provide a delay equal to a different one of mT(m=1,N) and mT+δ(m=1,N), where T is a delay smaller than the inverse of a bandwidth of the transmitter and receiver, and δ is ¼fc, where fc is the carrier frequency of an RF signal transmitted by the transmitter.
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Citations
20 Claims
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1. A radio interference cancelation device that cancels self-interference from a transmitter to a receiver, the system comprising:
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a 2N-way RF power splitter having an input and 2N outputs, wherein N is an integer; a power combiner having 2N+1 inputs and an output; and 2N adaptively controllable attenuators, each adaptively controllable attenuator coupled by cables between a different output of the 2N-way RF power splitter and a different input of the power combiner, each cable having a total length selected to provide a delay equal to a different one of mT(m=1,N) and mT+δ
(m=1,N), where T is a delay smaller than the inverse of a bandwidth of the transmitter and receiver, and δ
is ¼
fc, where fc is the carrier frequency of an RF signal transmitted by the transmitter. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A method for canceling self-interference from a transmitter to a receiver at a radio frequency frontend, the method comprising:
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splitting an output RF signal from the transmitter into 2N analog signal paths; providing in each signal path an adaptively controllable attenuator and a delay element, each delay element providing a delay equal to a different one of mT (m=1,N) and mT+δ
(m=1,N), where T is a delay smaller than the inverse of a bandwidth of the transmitter and receiver, and δ
is ¼
fc, where fc is the carrier frequency of an RF signal transmitted by the transmitter, andcombining outputs of all of the adaptively controllable attenuators delay elements with an RF signal received from the transmitter on a receive antenna. - View Dependent Claims (14, 15, 16, 17, 18, 19)
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20. A radio interference cancelation system that cancels self-interference from a transmitter to a receiver, the system comprising:
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a radio frequency transmitter coupled to a transmit antenna through an output of an RF power amplifier, an input attenuator coupled to the output of the RF power amplifier; a 2N-way RF power splitter; a receive antenna; a power combiner having 2N+1 inputs, one input of the power combiner coupled to the receive antenna; a low noise amplifier for a radio frequency receiver coupled to an output of the power combiner; 2N adaptively controllable attenuators, each adaptively controllable attenuator coupled by cables between a different output of the 2N-way RF power splitter and a different input of the power combiner, each cable having a total length selected to provide a delay equal to a different one of mT(m=1,N) and mT+δ
(m=1,N), where T is a delay smaller than the inverse of a bandwidth of the transmitter and receiver, and δ
is ¼
fc, where fc is the carrier frequency of an RF signal transmitted by the transmitter.
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Specification