US 9,287,920 B2 · Diplexer elimination in microwave point-to-point FDD systems

Abstract

A circulator based transceiver sharing a common antenna between a receive signal path and a transmit signal path is disclosed. Techniques to reduce coupled transmit signals and coupled transmit noise in a receive signal path, implemented in a variety of embodiments is disclosed allowing elimination of a diplexer, simplification of circulator design and reduction of transceiver cost. The transceiver includes means to generate and couple a correction signal into the receive signal path to attenuate coupled transmit signal in the receive path. Furthermore, the transceiver includes echo cancellation techniques to attenuate transmit noise in the receive signal path. Methods to utilize the transceiver to attenuate coupled transmit signal and transmit noise may improve transceiver efficiency, for example, in demodulation techniques and processing of data signal.

Claims20

Dependent claims

A method to reduce interference in a communication system, the method comprising:

transmitting a first signal comprising a transmit signal and a transmit noise;
receiving a second signal comprising a receive signal, a coupled transmit signal, and a coupled transmit noise;
calculating a gain parameter with a transmit signal echo canceller based on the first signal;
calculating a phase parameter with the transmit signal echo canceller based on the first signal;
generating a correction signal using the gain parameter and the phase parameter;
attenuating the coupled transmit signal from the second signal by combining the correction signal with the second signal;
and
attenuating the coupled transmit noise from the second signal with a transmit noise echo canceller.

5 more elements

An apparatus to reduce interference, comprising:

a transmit upconverter configured to upconvert a first signal comprising a transmit signal and a transmit noise;
a power amplifier, coupled to the transmit upconverter, configured to amplify the first signal;
a receive input configured to receive a second signal comprising a receive signal, a coupled transmit signal coupled from the transmit signal, and a coupled transmit noise coupled from the transmit noise;
a transmit feedback downconverter, coupled to the power amplifier, configured to downconvert the transmit signal:
a gain correction unit, coupled to the power amplifier, configured to modify a magnitude of the transmit signal with a gain parameter;
a phase correction unit, coupled to the gain correction unit, configured to modify a phase angle of the transmit signal with a phase parameter to generate a correction signal;
a transmit signal echo canceller, coupled to the transmit feedback downconverter, the gain correction unit, and the phase correction unit, configured to calculate the gain and phase parameters and configure the gain and phase correction units;
a transmit noise downconverter configured to downconvert the transmit noise;
a signal coupler, coupled to the phase correction unit and the receive input, configured to attenuate the coupled transmit signal in the second signal by combining the correction signal with the second signal;
a receive signal downconverter, coupled to the signal coupler, configured to downconvert the second signal;
and
a transmit noise echo canceller, coupled to the receive signal downconverter and the transmit noise downconverter, configured to attenuate the coupled transmit noise in the second signal.

9 more elements

An apparatus to reduce interference, comprising:

a transmit upconverter configured to upconvert a first signal comprising a transmit signal and a transmit noise;
a power amplifier, coupled to the transmit upconverter, configured to amplify the first signal;
a receive input configured to receive a second signal comprising a receive signal, a coupled transmit signal coupled from the transmit signal, and a coupled transmit noise coupled from the transmit noise;
a transmit feedback downconverter, coupled to the power amplifier, configured to downconvert the transmit signal;
a transmit signal echo canceller, coupled to the transmit feedback downconverter, configured to calculate a gain parameter and a phase parameter and generate a correction signal from the gain and phase parameters;
a transmit noise downconverter configured to downconvert the transmit noise;
a signal coupler, coupled to the transmit signal echo canceller and the receive input, configured to attenuate the coupled transmit signal in the second signal by combining the correction signal with the second signal;
a receive signal downconverter, coupled to the signal coupler, configured to downconvert the second signal;
and
a transmit noise echo canceller, coupled to the receive signal downconverter and the transmit noise downconverter, configured to attenuate the coupled transmit noise in the second signal.

7 more elements

Dependencies are inferred from the claim text.

Diplexer elimination in microwave point-to-point FDD systems

Life of this patent

Diplexer elimination in microwave point-to-point FDD systems

Life of this patent

Abstract

Claims20