JP7672354B2 - Radio, radio system, and radio method - Google Patents

Description

The present invention relates to a radio device that communicates using multi-channel radio signals, and in particular to a radio device, radio system, and radio method that eliminates multi-channel interference waves.

[Prior Art]
In conventional wireless systems, an automatic gain control (AGC) circuit is used in the reception processing of a wireless device to correct the reception power to a constant level in order to prevent a drop in the reception power.
Furthermore, some wireless systems use multiple channels for communication, and in such cases, processing is performed to cancel interference waves for each of the multiple channels.

[Conventional radio: Figure 3]
A radio device used in a conventional wireless system will be described with reference to Fig. 3. Fig. 3 is a schematic diagram of the configuration of a conventional radio device.
As shown in FIG. 3, a conventional radio basically comprises an antenna 1, a first coupler (CPL) 2, an analog/digital converter (A/D) 3, an interference wave detection unit 4, a delay unit 5, a second coupler (CPL) 6, a digital/analog converter (D/A) 7, a first automatic gain control circuit (AGC) 8, an analog/digital converter (A/D) 9, an interference wave canceller 10, and a demodulation unit 30.
Incidentally, an interference wave canceller 10 is provided for each of a plurality of channels, and outputs from the interference wave cancellers 10 are integrated and input to the D/A 7 .

In a conventional wireless device, an interference wave detection unit 4 detects an interference wave signal a from a signal b received by an antenna 1, an interference wave canceller 10 generates a cancellation signal (canceller signal) c that cancels the interference wave, combines this with the signal received by a second CPL 6, and outputs a residual signal d to a first AGC 8.
Here, although the interference wave has been cancelled, the interference wave still remains in the residual signal d, and the residual signal d contains both the desired wave and the interference wave.
The configuration and operation of the interference wave canceller 10 will be described later.

The first AGC 8 controls the gain so as to follow the change in the residual signal (desired signal and interference signal) in order to secure the dynamic range of the A/D 9 .
The gain-controlled residual signal e is input to the interference wave canceller 10, and a cancellation signal c for canceling the interference wave is updated based on the residual signal e, and is combined in the second CPL 6 via the D/A 7.
The updated interference wave cancellation signal c is repeatedly combined with the received signal to cause the canceller to converge, the interference wave is removed from the received signal, and the signal from which the interference wave has been removed is demodulated by the demodulator 30 .

[Conventional interference wave canceller: Figure 4]
A conventional interference wave canceller 10 will be described with reference to Fig. 4. Fig. 4 is a schematic diagram showing the configuration of a conventional interference wave canceller.
As shown in FIG. 4, the conventional interference wave canceller 10 includes quadrature detectors (Q-DET) 11 and 12, a delay adjustment section 13, a weight update section 14, an adaptive filter 15, and a quadrature modulator (Q-MOD) 16.

The Q-DET 11 inputs the interference wave signal (interference wave frequency) a from the interference wave detection unit 4 and the digitally converted received signal b from the A/D 3, performs quadrature detection, and outputs the quadrature detection signal to the adaptive filter 15 and the delay adjustment unit 13.
The delay adjustment unit 13 delays the quadrature detection signal from the Q-DET 11 in accordance with the signal delays in the delay unit 5 , the second CPL 6 , the first AGC 8 , and the A/D 9 .

The Q-DET 12 receives the digitally converted residual signal e from the A/D 9 and the interference signal a from the interference detector 4, performs quadrature detection, and outputs the quadrature detection signal to the weight updater .
The weight updater 14 updates the filter weights of the adaptive filter 15 so that the quadrature detection signal from the delay adjuster 13 coincides with the quadrature detection signal of the residual signal e from the A/D 9 .

The adaptive filter 15 is an FIR (Finite Impulse Response) filter, which is a digital filter having a finite-time impulse response, and generates a quadrature detection signal for canceling (negating) the interference wave using the weight value set by the weight update unit 14.
The Q-MOD 16 performs quadrature modulation on the quadrature detection signal from the adaptive filter 15 and outputs it to the D/A 7 as an interference wave cancellation signal c.
By the above-mentioned configuration and operation of the interference wave canceller 10, an interference wave cancellation signal c for canceling an interference wave is generated.

[Related Technology]
As a related prior art, there is the "AGC circuit" disclosed in Japanese Patent Laid-Open Publication No. 11-195941 (Patent Document 1).
Patent Document 1 discloses an AGC circuit having a variable gain amplifier that determines the desired wave power and the interference wave power, and performs gain control that follows fluctuations in the desired wave power without following the interference wave power.

Japanese Patent Application Publication No. 11-195941

However, in radio devices with conventional AGC circuits, when canceling multi-channel interference, there was a problem in that the convergence time of the interference canceller became slower as convergence progressed.

Specifically, because the interference wave is larger than the desired wave, as the cancellation converges, the interference wave in the remaining signal (desired wave and interference wave) after cancellation rapidly attenuates and becomes smaller. As a result, the difference between the desired wave and interference wave in the remaining signal becomes smaller, and adjusting the adaptive filter based only on that difference results in a long convergence time.

In addition, Patent Document 1 does not describe a configuration for generating an interference wave canceller signal using a residual signal whose gain is controlled so as to keep the received power of the desired wave constant when removing interference waves.

The present invention has been made in consideration of the above-mentioned circumstances, and aims to provide a radio device, a radio system, and a radio method that can quickly converge on canceling interference waves.

The present invention, which is intended to solve the problems of the above-mentioned conventional examples, is a radio device that removes interference waves from multi-channel radio signals, and is characterized in that it generates an interference wave canceller signal that cancels the interference wave for each channel from a received radio signal, combines the interference wave canceller signal with the radio signal to obtain a residual signal, controls the gain of the residual signal so as to keep the received power of a desired wave in the residual signal constant, and updates the interference wave canceller signal using the gain-controlled residual signal.

The present invention is characterized in that the radio is provided with an AGC circuit that controls the gain of the residual signal to keep the received power of the desired wave constant, and the AGC circuit has a desired wave detection unit that detects the desired wave from the residual signal, a calculation unit that calculates an average power value from the detected desired wave, and a multiplier that multiplies the residual signal by the reciprocal of the average power value.

The present invention is a wireless system that includes the above-mentioned wireless device.

The present invention is a wireless method for removing interference waves from multi-channel radio signals, and is characterized in that it generates an interference wave canceller signal that cancels the interference wave for each channel from a received radio signal, combines the interference wave canceller signal with the radio signal to obtain a residual signal, controls the gain of the residual signal so as to keep the received power of a desired wave in the residual signal constant, and updates the interference wave canceller signal using the gain-controlled residual signal.

According to the present invention, a radio device that removes interference waves from multi-channel radio signals generates an interference wave canceller signal that cancels the interference wave for each channel from a received radio signal , synthesizes the interference wave canceller signal with the radio signal to obtain a residual signal, controls the gain of the residual signal so as to keep the received power of a desired wave in the residual signal constant, and updates the interference wave canceller signal using the gain-controlled residual signal.Since the interference wave is canceled based on the residual signal that is gain-controlled to keep the received power of the desired wave constant, the level of the interference wave can be optimized and the cancellation of the interference wave can be converged quickly.

FIG. 2 is a schematic diagram of the configuration of the radio device. FIG. 4 is a schematic diagram of the configuration of a second AGC. FIG. 1 is a schematic diagram illustrating the configuration of a conventional wireless device. FIG. 1 is a schematic diagram illustrating the configuration of a conventional interference wave canceller.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to the drawings.
[Outline of the embodiment]
A radio according to an embodiment of the present invention (this radio) is a radio that removes interference waves from multi-channel radio signals, and when removing interference waves by combining an interference wave canceller signal that cancels interference waves for each channel with a received radio signal, the interference wave canceller signal is updated using a residual signal whose gain is controlled to keep the received power of the desired wave constant. Since the interference wave is canceled based on the residual signal whose gain is controlled to keep the received power of the desired wave constant, the level of the interference wave can be optimized and the cancellation of the interference wave can be converged quickly.

The wireless system according to the embodiment of the present invention (this system) includes multiple wireless devices as described above, and can quickly cancel interference waves and achieve stable communication.

[This radio: Figure 1]
The present radio device will be described with reference to Fig. 1. Fig. 1 is a schematic diagram of the configuration of the present radio device.
As shown in FIG. 1, this radio basically comprises an antenna 1, a first coupler (CPL) 2, an analog/digital converter (A/D) 3, an interference wave detection unit 4, a delay unit 5, a second coupler (CPL) 6, a digital/analog converter (D/A) 7, a first automatic gain control circuit (AGC) 8, an analog/digital converter (A/D) 9, an interference wave canceller 10, a second automatic gain control circuit (AGC) 20, and a demodulation unit 30.
As in the conventional case, an interference wave canceller 10 is provided for each of a plurality of channels, and outputs from the interference wave cancellers 10 are integrated and input to the D/A 7 .

[Each part]
Each part of this radio device will now be described in detail.
The antenna 1 receives multi-channel radio signals.
The first CPL 2 distributes the signal received by the antenna 1 to the A/D 3 and the delay unit 5 .
The A/D 3 converts the signal from the first CPL 2 from analog to digital and outputs the signal to the interference wave detection unit 4. The signal b digitally converted by the A/D 3 is also branched and output to the interference wave canceller 10.

The interference wave detector 4 detects an interference wave (U wave) from the digital signal b from the A/D 3 , and outputs an interference wave signal (interference wave frequency) a to the interference wave canceller 10 .
The delay unit 5 delays the analog signal from the first CPL 3 by the time required for the interference wave canceller 10 to cancel the interference wave, and outputs the delayed signal to the second CPL 6 .

The second CPL 6 combines the analog signal from the delay unit 5 with the interference wave canceller signal (cancellation signal) c from the D/A 7 , and outputs a residual signal d after cancellation to the first AGC 8 .
The D/A 7 converts the interference wave canceller signal c from the interference wave canceller 10 from digital to analog and outputs it to the second CPL 6 .

The first AGC 8 controls the gain of the residual signal (desired signal and interference signal) after cancellation from the second CPL 6 so as to follow changes in the residual signal in order to ensure the dynamic range of the A/D 9, and outputs the signal to the A/D 9.
The A/D 9 converts the automatic gain controlled residual signal from the first AGC 8 from analog to digital and outputs it to the second AGC 20 .

As explained in FIG. 4, the interference wave canceller 10 generates an interference wave canceller signal c that cancels the interference wave detected by the interference wave detector 4 based on a residual signal d that is gain-controlled to keep the received power of the desired wave from the second AGC 20 constant, and outputs the generated signal to the D/A 7.

The second AGC 20 performs automatic gain control on the residual signal d from the A/D 9 so that the received power of the desired wave becomes constant, and outputs the gain-controlled residual signal e to the interference wave canceller 10 and demodulation section 30 .
The demodulation section 30 demodulates the residual signal e that has been gain-controlled by the second AGC 20 .

In other words, the residual signal that has been gain-controlled by the second AGC 20 so that the received power of the desired wave is constant contains an interference wave, and the interference wave of the residual signal that is rapidly attenuated by the cancellation process can be brought to an appropriate level based on the constant received power of the desired wave.
This involves the second AGC 20 keeping the reception power of the desired wave constant, changing (updating) the level of the interference wave to an appropriate level based on that, and carrying out cancellation processing.

[Second AGC 20: FIG. 2]
Next, the second AGC 20 will be described with reference to Fig. 2. Fig. 2 is a schematic diagram of the configuration of the second AGC.
As shown in FIG. 2, the second AGC 20 includes a desired wave detection section 21, a desired wave average power calculation section 22, and a multiplier 23.

The desired wave detection unit 21 receives the digitally converted residual signal from the A/D 9 , detects a desired wave (D wave) of a frequency that has been recognized in advance for a specific channel, and outputs the detected signal to a desired wave average power calculation unit 22 .
The desired wave average power calculation unit 22 receives the desired wave (D wave) detected by the desired wave detection unit 21 , calculates the average power value (Dp) of the desired wave, and outputs it to the multiplier 23 .

The multiplier 23 multiplies the digitally converted residual signal from the A/D 9 by the inverse of the average power value (Dp) from the desired wave average power calculation unit 22, and outputs the gain-controlled residual signal e for the desired wave to the interference wave canceller 10 and the demodulation unit 30.

[Action]
Next, the operation of this radio device will be described.
In this radio device, an interference wave detection unit 4 detects an interference wave signal a from a signal b received by an antenna 1, an interference wave canceller 10 generates a canceller signal c that cancels the interference wave, combines this with the signal received by a second CPL 6, and outputs a residual signal d to a first AGC 8.

The first AGC 8 controls the gain so as to follow the change in the residual signal (desired signal and interference signal) in order to secure the dynamic range of the A/D 9 .
The gain-controlled residual signal e is A/D converted and then gain-controlled by a second AGC 20 so that the received power of the desired wave is constant. The gain-controlled residual signal e is input to an interference wave canceller 10, and a canceller signal c that cancels the interference wave is updated based on the residual signal e, and is synthesized by a second CPL 6 via a D/A 7.
The updated interference wave canceller signal c is repeatedly combined with the received signal to cause the canceller to converge, the interference wave is removed from the received signal, and the signal from which the interference wave has been removed is demodulated by demodulator 30 .

In addition, by providing multiple radio devices in this system, interference waves in each radio device can be quickly canceled, resulting in stable communications.

[Effects of the embodiment]
According to this radio device, which is a radio device that removes interference waves from multi-channel radio signals, an interference wave canceller signal c that cancels the interference wave for each channel is generated by the interference wave canceller 10 for a received radio signal b, and when the radio signal b and the interference wave canceller signal c are synthesized by the second CPL 6 to remove the interference wave, the second AGC 20 updates the interference wave canceller signal using a residual signal e whose gain is controlled so as to keep the reception power of the desired wave constant. Therefore, since the interference wave is canceled based on the residual signal e whose gain is controlled so as to keep the reception power of the desired wave constant, it is possible to optimize the level of the interference wave and achieve the effect of quickly converging the cancellation of the interference wave.

In addition, this system is equipped with multiple radio devices, which has the effect of quickly canceling interference waves in each radio device and achieving stable communication.

The present invention is suitable for radio devices, radio systems, and radio methods that can quickly converge on canceling interference waves.

1...antenna, 2...first coupler (CPL), 3...analog/digital converter (A/D), 4...interference wave detection unit, 5...delay unit, 6...second coupler (CPL), 7...digital/analog converter (D/A), 8...first automatic gain control circuit (AGC), 9...analog/digital converter (A/D), 10...interference wave canceller, 11, 12...quadrature detector (Q-DET), 13...delay adjustment unit, 14...weight update unit, 15...adaptive filter, 16...quadrature modulator (Q-MOD), 20...second automatic gain control circuit (AGC), 21...desired wave detection unit, 22...desired wave average power calculation unit, 23...multiplier, 30...demodulation unit

Claims (4)

A radio device for removing interference waves from multi-channel radio signals, comprising:
A radio device comprising: a first receiving unit that receives a first signal from a second receiving channel of the first radio signal; a second receiving unit that receives a second signal from the second receiving channel of the first radio signal; a third receiving unit that receives a second signal from the first receiving channel of the first radio signal; a fourth receiving unit that receives a second signal from the first receiving channel of the first radio signal; a fifth receiving unit that receives a third signal from the first receiving channel of the first radio signal; an AGC circuit for controlling a gain of a residual signal so as to keep the received power of the desired wave constant;
2. The radio device according to claim 1, wherein the AGC circuit comprises a desired wave detection unit that detects the desired wave from the residual signal, a calculation unit that calculates an average power value from the detected desired wave, and a multiplier that multiplies the residual signal by the reciprocal of the average power value. A radio system comprising the radio device according to claim 1 or 2. A wireless method for removing interference waves from a multi-channel wireless signal, comprising:
A wireless method comprising the steps of: generating an interference wave canceller signal that cancels interference waves for each channel from a received wireless signal; synthesizing the interference wave canceller signal with the wireless signal to obtain a residual signal; controlling a gain of the residual signal so as to keep constant the received power of a desired wave in the residual signal; and updating the interference wave canceller signal using the gain-controlled residual signal.

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