ALL-ANALOG AND HYBRID RADIO INTERFERENCE CANCELATION USING CABLES, ATTENUATORS AND POWER SPLITTERS
1 Assignment
0 Petitions
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.
45 Citations
50 Claims
-
1-29. -29. (canceled)
-
30. A radio interference cancellation 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; 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 (31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41)
-
-
42. A method for canceling self-interference from a transmitter to a receiver at a radio frequency frontend, the method comprising:
-
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 (43, 44, 45, 46, 47, 48)
-
-
49. A radio interference cancellation system that cancels self-interference from a transmitter to a receiver, the system comprising:
-
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.
-
-
50. A radio interference cancellation device that cancels self-interference from a transmitter to a receiver, the system comprising:
-
a signal input channel including a baseband-frequency sampler, a low pass filter and an analog-to-digital converter; an adaptive digital filter coupled to an output of the signal input channel; a digital-to-analog converter coupled to an output of the adaptive digital filter.
-
Specification