Satellite communication system and method of cancelling interference in the satellite communication system

Patent metadata

Field	Value
Publication number	US-9755730-B2
Application number	US-201615006527-A
Country	US
Kind code	B2
Filing date	Jan 26, 2016
Priority date	Jan 26, 2015
Publication date	Sep 5, 2017
Grant date	Sep 5, 2017

Abstract

A satellite communication system and a method of cancelling interference in the satellite communication system are disclosed. The method of cancelling interference in the satellite communication system may include receiving a signal by a central station from a terminal via a satellite transponder, estimating, from the signal, a nonlinear characteristic associated with a central station signal transmitted from the central station, and cancelling an interference signal from the signal using the estimated nonlinear characteristic.

First claim

What is claimed is:

1. A method of cancelling interference in a satellite communication system, the method comprising:
receiving, by a central station, a signal from a terminal via a satellite transponder; estimating, from the received signal, a nonlinear characteristic associated with a central station signal transmitted from the central station; and
cancelling an interference signal from the signal using the estimated nonlinear characteristic,
wherein a frequency band of the signal comprises a frequency band allocated to a re-input signal to be re-input to the central station through the satellite transponder receiving the central station signal, and a frequency band allocated to a terminal signal to be transmitted to the central station from the terminal.

2. The method of claim 1 , wherein the estimating of the nonlinear characteristic comprises:
estimating a high power amplifier (HPA) nonlinear characteristic by the central station; or
estimating an HPA nonlinear characteristic by an interaction between the central station and the satellite transponder.

3. The method of claim 1 , wherein the estimating of the nonlinear characteristic comprises: estimating, from the signal, the nonlinear characteristic in consideration of the re-input signal to be re-input to the central station by the satellite transponder receiving the central station signal.

4. The method of claim 1 , wherein the cancelling of the interference signal comprises:
demodulating the signal by performing at least one of symbol timing recovery (STR), carrier frequency offset (CFO) measurement, and phase tracking; and
specifying the interference signal to be cancelled by adding, to an intermediate frequency (IF) band signal using an IF band in the central station signal, the estimated nonlinear characteristic and signal information associated with at least one of a timing error, a frequency error, and a phase error generated through the demodulating of the signal.

5. The method of claim 1 , wherein the cancelling of the interference signal comprises: specifying, as the interference signal to be cancelled, the re-input signal in the signal to be re-input to the central station by the satellite transponder receiving the central station signal.

6. The method of claim 5 , wherein the cancelling of the interference signal further comprises: cancelling the re-input signal comprised in the signal by an adaptive filter having the nonlinear characteristic.

7. The method of claim 1 , further comprising: obtaining a terminal signal to be transmitted to the central station from the terminal by cancelling the interference signal from the signal.

8. The method of claim 1 , wherein the frequency band allocated to the terminal signal is allocated to overlap at least a portion of the frequency band allocated to the re-input signal.

9. The method of claim 1 , wherein the terminal signal is maintained to be smaller than the central station signal by a preset amplitude.

10. A method of cancelling interference in a satellite communication system, the method comprising:
receiving an overlapping signal to be transmitted to a central station of the satellite communication system via a satellite transponder through a first frequency band;
estimating, from the overlapping signal, a nonlinear characteristic associated with a central station signal;
generating an interference signal for the overlapping signal using the estimated nonlinear characteristic; and
cancelling the generated interference signal from the overlapping signal,
wherein, when the central station signal is transmitted to at least one terminal from the central station via the satellite transponder through a second frequency band comprised in the first frequency band, the estimating of the nonlinear characteristic comprises: estimating the nonlinear characteristic using an intermediate frequency (IF) band signal using an IF band in the central station signal and a re-input signal to be re-input to the central station by the satellite transponder receiving the central station signal.

11. The method of claim 10 , further comprising:
demodulating the overlapping signal by performing at least one of symbol timing recovery (STR), carrier frequency offset (CFO) measurement, and phase tracking on the received overlapping signal, and wherein the generating of the interference signal comprises: adding the estimated nonlinear characteristic to the IF band signal; and
generating, as the interference signal, a signal similar to the re-input signal by further adding, to the IF band signal, signal information associated with at least one of a timing error, a frequency error, and a phase error generated through the demodulating of the overlapping signal.

12. The method of claim 10 , wherein the cancelling of the generated interference signal comprises: obtaining a terminal signal by cancelling the generated interference signal from the overlapping signal using an adaptive filter.

13. A satellite communication system, comprising:
a receiver configured to receive a signal by a central station from a terminal via a satellite transponder;
an estimator configured to estimate, from the received signal, a nonlinear characteristic associated with a central station signal transmitted from the central station; and
a canceller configured to cancel an interference signal from the signal using the estimated nonlinear characteristic,
wherein the estimator is configured to add the estimated nonlinear characteristic to an intermediate frequency (IF) band signal using an IF band in the central station signal, and the canceller is configured to demodulate the signal by performing at least one of symbol timing recovery (STR), carrier frequency offset (CFO) measurement, and phase tracking, and specify the interference signal to be cancelled by further adding, to the IF band signal, signal information associated with at least one of a timing error, a frequency error, and a phase error generated through the demodulating of the signal.

14. The system of claim 13 , wherein the estimator is configured to estimate a high power amplifier (HPA) nonlinear characteristic by the central station or an HPA nonlinear characteristic by an interaction between the central station and the satellite transponder.

15. The system of claim 13 , wherein the estimator is configured to estimate, from the signal, the nonlinear characteristic in consideration of a re-input signal to be re-input to the central station by the satellite transponder receiving the central station signal.

16. The system of claim 13 , wherein the canceller is configured to cancel a re-input signal in the signal by an adaptive filter having the nonlinear characteristic.

17. The system of claim 13 , wherein the canceller is configured to obtain a terminal signal transmitted from the terminal to the central station by cancelling the interference signal from the signal.

Assignees

• Electronics & Telecommunications Res Inst

Inventors

• Ryu Joon Gyu

Classifications

• H04B7/18517

  Transmission equipment in earth stations · CPC title

• H04B7/18513 Primary

  Transmission in a satellite or space-based system · CPC title

• H04B15/005

  Reducing noise, e.g. humm, from the supply · CPC title