Systems and methods for asynchronous re-modulation with adaptive I/Q adjustment

Patent metadata

Field	Value
Publication number	US-9813198-B2
Application number	US-201414506452-A
Country	US
Kind code	B2
Filing date	Oct 3, 2014
Priority date	Sep 26, 2011
Publication date	Nov 7, 2017
Grant date	Nov 7, 2017

Abstract

Various embodiments provide for systems and methods for signal conversion of one modulated signal to another modulated signal using demodulation and then re-modulation. According to some embodiments, a signal receiving system may comprise an I/Q demodulator that demodulates a first modulated signal to an in-phase (“I”) signal and a quadrature (“Q”) signal, an I/Q signal adjustor that adaptively adjusts the Q signal to increase the signal-to-noise ratio (SNR) of a transitory signal that is based on a second modulated signal, and an I/Q modulator that modulates the I signal and the adjusted Q signal to the second modulated signal. To increase the SNR, the Q signal may be adjusted based on a calculated error determined for the transitory signal during demodulation by a demodulator downstream from the I/Q modulator.

First claim

What is claimed is:

1. A receiver system, comprising:
a radio antenna configured to receive a first modulated signal from a remote transmitter;
an I/Q demodulator configured to use a local oscillator to demodulate the first modulated signal to a first in-phase (“I”) receive signal and a first quadrature (“Q”) receive signal, the first modulated signal being previously modulated using a transmitter oscillator that is not synchronized with the local oscillator, the transmitter oscillator residing in the remote transmitter;
an I/Q signal adjuster configured to adaptively adjust the first I receive signal or the first Q receive signal based on one or more first control signals;
an I/Q modulator configured to modulate the first I and Q receive signals as adjusted to generate a first transitory receive signal;
a downstream demodulator configured to demodulate the first transitory receive signal; and
a transmitter circuit configured to transmit one or more second control signals to the I/Q signal adjuster, the one or more second controls signals being generated based on a value indicative of a signal-to-noise ratio (SNR) in the first transitory receive signal, the one or more second control signals being generated to adaptively adjust a second receive signal or a second Q receive signal to attempt to increase SNR in a second transitory receive signal generated by the I/Q modulator using the second I and Q receive signals as adjusted, the second I and Q receive signals being generated by the I/Q demodulator based on a second modulated signal received from the remote transmitter.

2. The receiver system of claim 1 , wherein the downstream demodulator is further configured to demodulate the first transitory receive signal to a data signal.

3. The receiver system of claim 1 , wherein the one or more first control signals are generated based on a calculated error, the calculated error is determined based on a means squared error (MSE) by applying a steepest descent algorithm to the MSE.

4. The receiver system of claim 1 , wherein the receiver system comprises an in-door unit (IDU), the IDU comprising the downstream demodulator.

5. The receiver system of claim 4 , wherein an out-door unit (ODU) comprises the I/Q signal adjuster, the I/Q demodulator, and the I/Q modulator.

6. The receiver system of claim 5 , wherein the IDU is coupled to the ODU over a coaxial cable.

7. The receiver system of claim 1 , wherein the transmitter circuit transmits the one or more second control signals to the I/Q signal adjuster as telemetry data.

8. The receiver system of claim 7 , wherein the I/Q signal adjuster is configured to adaptively adjust the second I receive signal or the second Q receive signal using the telemetry data.

9. The receiver system of claim 1 , wherein the receiver system includes a remote access card (RAC).

10. The receiver system of claim 1 , wherein the receiver system is coupled to the remote transmitter over a wireless link.

11. A method executed at a receiver system, the method comprising:
receiving a first modulated signal from a remote transmitter;
using a local oscillator to demodulate the first modulated signal to a first in-phase (“I”) receive signal and a first quadrature (“Q”) receive signal, the first modulated signal being previously modulated using a transmitter oscillator that is not synchronized with the local oscillator, the transmitter oscillator residing in the remote transmitter;
using an I/Q signal adjuster to adaptively adjust the first I receive signal or the first Q receive signal based on one or more first control signals;
modulating the first I and Q receive signals as adjusted to generate a first transitory receive signal;
demodulating the first transitory receive signal;
generating one or more second control signals based on the first transitory receive signal;
transmitting the one or more second control signals to the I/Q signal adjuster;
receiving a second modulated signal from the remote transmitter;
using the local oscillator to demodulate the second modulated signal to a second I receive signal and a second Q receive signal, the second modulated signal being previously modulated using the transmitter oscillator residing in the remote transmitter; and
using the I/O signal adjuster to adaptively adjust the second I receive signal or the second Q receive signal to attempt to increase a signal-to-noise ratio (SNR) in a second transitory receive signal generated using the second I and Q receive signals as adjusted.

12. The method of claim 11 , further comprising demodulating the first transitory receive signal to a data signal.

13. The method of claim 11 , further comprising determining a calculated error based on a mean-squared-error (MSE) by applying a steepest descent algorithm to the MSE.

14. The method of claim 11 , wherein the first transitory signal is received from an out-door unit (ODU) by an in-door unit (IDU) via a cable.

15. The method of claim 14 , wherein the cable comprises a coaxial cable.

16. The method of claim 11 , wherein an out-door unit (ODU) comprises the I/Q signal adjuster, an I/Q demodulator, and an I/Q modulator.

17. The method of claim 11 , wherein the transmitting the one or more second control signals to the I/Q signal adjuster comprises transmitting the one or more second control signals to the I/Q signal adjuster as telemetry data.

18. The method of claim 17 , wherein the adaptively adjusting the second I receive signal or the second Q receive signal is based on the telemetry data.

19. The method of claim 11 , wherein the receiver system is coupled to the remote transmitter over a wireless link.

Assignees

• Aviat Us Inc

Inventors

• Vann Emerick
• Chao Yen-Fang
• Qin Youming
• Matian Roland

Classifications

• H04B1/28

  the receiver comprising at least one semiconductor device having three or more electrodes · CPC title

• H04B1/0014

  using DSP [Digital Signal Processor] quadrature modulation and demodulation · CPC title

• H04L27/38

  Demodulator circuits; Receiver circuits · CPC title

• H03C3/406

  using a feedback loop containing mixers or demodulators · CPC title

• H04B1/10

  Means associated with receiver for limiting or suppressing noise or interference · CPC title