Noise canceller device

Abstract

In a noise canceller device, interference signal adjustment units adjust delay, phase and amplitude of a signal received by a sub antenna under different conditions to obtain adjustment signals, and subtract the adjustment signals from a signal received by a main antenna to obtain differential signals. An average power calculation unit calculates an average power for each of the differential signals. An optimal condition search unit determines the values of delay, phase and amplitude that result in the minimum average power, and sets the values in an optimal interference signal adjustment unit. The optimal interference signal adjustment unit adjusts the signal received by the sub antenna using optimal values for delay, phase and amplitude to obtain an optimal adjustment signal. A cancellation unit subtracts the optimal adjustment signal from the signal received by the main antenna to remove interference signals, and outputs a desired signal to a host device.

Description

FIELD OF THE INVENTION[0001]The present invention relates to a noise canceller device in a wireless system; and, more particularly, to a noise canceller device capable of removing interference signals from another system accurately and stably.BACKGROUND OF THE INVENTION[0002]In a conventional wireless communication system, a desired signal interferes with a signal of another system, which may result in deterioration of a communication environment.[0003]For example, in BS (Broadcasting Satellite) reception facilities having a BS antenna installed at each home, frequency conversion is often used to process a received signal. At that time, if radio waves leak from the reception facilities, interference may occur in a band of a cellular phone system.[0004]A signal band of satellite broadcasting which becomes an interference signal is wider than the band of the cellular phone which is a desired signal and, thus, it is difficult to remove the interference signal by a filter or the like.[0...

AI Technical Summary

Benefits of technology

The noise canceller device described in this patent is designed to remove interference signals in an environment where both the desired signal and the interference signal are present. It includes multiple interference signal adjustment units that adjust the delay, phase, and amplitude of the interference signal received by a second antenna. Adders and average power calculation units are used to determine the optimal values for these adjustments. An optimal condition search unit is used to determine the minimum average power as the optimal condition for the interference signal adjustment. An optimal interference signal adjustment unit is used to adjust the signal received by the second antenna based on the optimal conditions. A cancellation unit is used to subtract the output of the optimal interference signal adjustment unit from the signal received by the first antenna. The device can accurately and stably remove interference signals in an environment where they are present and the desired signal is intermittent.

Problems solved by technology

In a conventional wireless communication system, a desired signal interferes with a signal of another system, which may result in deterioration of a communication environment.

At that time, if radio waves leak from the reception facilities, interference may occur in a band of a cellular phone system.

A signal band of satellite broadcasting which becomes an interference signal is wider than the band of the cellular phone which is a desired signal and, thus, it is difficult to remove the interference signal by a filter or the like.

However, when a replica of the interference signal cannot be prepared, it is difficult to remove only the interference signal.

When the interference signal cannot be removed, the communication quality of a cellular phone which is a desired signal deteriorates.

However, the conventional noise canceller device does not sufficiently consider the accurate and stable removal of the interference signals in an environment where the interference signal is steadily present and the desired signal is not steadily present.

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