JPH11251987A - Radio repeater - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress a creeping interference wave even if a distance between antennas is reduced by detecting a direction where a signal from a base station arrives and a direction where an interference wave arrives, calculating the weighting coefficient of the reception antenna to suppress the interference wave, weighting it and receiving a signal. SOLUTION: A control part 6 detects a direction where the receiving signal strength indicator(RSSI) of a signal (desired wave) arriving at a first antenna 1 becomes maximum. When such a direction is detected, the control part 6 turns on a gain variable repeating amplifier 7 and detects a direction where RSSI of a signal (interference wave) creeping around the first antenna 1 from a second antenna 8 becomes maximum while gradually increasing the gain of the gain variable repeater 7. A phase control part 2 and an amplitude control part 3 are controlled by using a weighting coefficient so that RSSI of the desired wave arriving at the first antenna 1 becomes maximum on a condition that an interference wave direction becomes a null point based on the direction of the arriving desired wave and the direction of the interference wave.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radio relay apparatus for relaying a signal, such as a portable telephone, and more particularly to a radio relay apparatus capable of suppressing wraparound interference.

[0002]

2. Description of the Related Art In recent years, wireless communication systems such as mobile phones have become widespread, but zones where radio waves from base stations do not directly reach are scattered in various places due to the conditions of surrounding buildings and the like. In order to respond to the desire to use a telephone, a wireless relay device that relays a signal from a base station is installed to cover the above-mentioned zone.

[0003] Generally, a radio relay device includes two antennas and a relay amplifier, receives a signal arriving from a base station by a receiving antenna, amplifies the signal by the relay amplifier, and transmits and outputs the signal from the transmitting antenna. Things.

[0004]

However, in the above-mentioned conventional wireless relay device, high-frequency coupling may occur between the receiving antenna and the transmitting antenna, and when the coupling has a certain strength or more. However, there is a problem that a signal transmitted and output from the transmitting antenna by the wireless relay device goes around to the receiving antenna and causes oscillation.

Therefore, measures have been taken to prevent the signal transmitted and output to the receiving antenna from entering the receiving antenna, for example, by securing a sufficient distance between the receiving antenna and the transmitting antenna.

However, it is difficult to secure a place for installing the wireless relay device in an area where buildings and the like are densely located in the city center, and it is difficult to secure a sufficient distance between the two antennas due to location restrictions. It is the current situation.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to provide a radio relay apparatus that can suppress a wraparound interference wave even when the distance between antennas is reduced.

[0008]

According to a first aspect of the present invention, there is provided a radio relay apparatus comprising a receiving antenna in which a plurality of antenna elements are arranged in an array. Detects the direction in which the signal from the station arrives and the direction in which the interference wave arrives, calculates the weighting coefficient of the receiving antenna for suppressing the interference wave based on the direction, and performs the weighting to receive the signal. The interference wave can be suppressed even if the distance between the antennas is shortened.

According to a second aspect of the present invention, there is provided a radio relay apparatus comprising: a receiving antenna in which a plurality of antenna elements are arranged in an array; A phase control circuit that controls the phase of a signal arriving at a corresponding antenna element, and an amplitude control circuit that is provided corresponding to the phase control circuit and controls the amplitude of a signal input from the corresponding phase control circuit. A synthesizing unit that synthesizes a signal input from the amplitude control circuit, a receiving unit that outputs a signal input from the synthesizing unit, and outputs a level of the signal as a reception level, and a signal that is input from the receiving unit. Variable gain amplifier for amplifying a signal with a specific gain, a transmitting antenna for radiating a signal input from the variable gain repeater amplifier, With the relay amplifier turned off, the signal arriving at the receiving antenna is set to only the desired wave, and the phase control circuit and the amplitude control circuit are controlled to check the condition that the reception level input from the reception unit is maximum, Detect the direction of arrival of the desired wave, then turn on the variable gain relay amplifier, while gradually increasing the amplification gain, control the phase control circuit and the amplitude control circuit, input from the receiving unit The reception level of the receiving antenna that suppresses the interference wave based on the arrival direction of the desired wave and the arrival direction of the interference wave is detected by examining the condition that the reception level of the reception wave becomes maximum. It has a control unit that calculates a weighting coefficient and controls a phase control circuit and an amplitude control circuit so as to receive a desired wave according to the weighting coefficient. It can be suppressed.

[0010] When the frequency of the signal to be relayed is high, in the wireless relay device according to the second aspect, the receiving unit includes:
A receiving unit that demodulates the input signal and outputs the demodulated signal to the variable gain relay amplifier, the variable gain amplifier remodulates the signal input from the receiving unit, amplifies the signal with a specific gain, and transmits the signal through the transmitting antenna It is preferable to use a variable gain relay amplifier that radiates light.

In the radio relay apparatus according to claim 2, when the frequency of the signal to be relayed is not so high, the receiving section outputs the input signal to the variable gain relay amplifier without demodulating the input signal. Preferably, the variable gain amplifier is a variable gain relay amplifier that amplifies a signal input from the receiving section with a specific gain and then radiates the signal as it is via a transmitting antenna.

[0012]

Embodiments of the present invention will be described with reference to the drawings. A wireless relay device according to an embodiment of the present invention includes an array receiving antenna, detects a direction in which a signal from a base station arrives and a direction in which an interference wave arrives, and based on information on these directions. And the calculation
It suppresses interference waves, and can suppress sneak interference waves even if the distance between antennas is shortened.

As shown in FIG. 1, a radio relay apparatus (this apparatus) according to an embodiment of the present invention
, A phase control unit 2, an amplitude control unit 3, a combining unit 4, a receiving unit 5, a control unit 6, a variable gain relay amplifier 7, and a transmitting antenna 8. FIG. 1 is a configuration block diagram of the present apparatus.

Hereinafter, each part will be described in detail. The receiving antenna 1 has a plurality of antenna elements arranged in an array.

Here, the array shape is specifically described in FIG.
As shown in FIG. 3A, the antenna elements are arranged on the line at a fixed interval d, and as shown in FIG.
It is conceivable that they are arranged at a constant interval d on the circumference. FIG. 3 is a perspective view showing a specific appearance of the receiving antenna 1. Here, the interval d is generally set to be a fraction of the wavelength to about the wavelength.

The phase control unit 2 includes a phase control circuit corresponding to each antenna element of the receiving antenna 1, receives signals arriving at each corresponding antenna element of the receiving antenna 1, and will be described later. It controls the phase of the received signal (received signal) according to an instruction input from the control unit 6.

The amplitude control unit 3 includes an amplitude control circuit corresponding to the phase control circuit of the phase control unit 2, and receives an input from the corresponding phase control circuit in response to an instruction input from the control unit 6 described later. This controls the amplitude of the signal to be transmitted.

The synthesizing section 4 synthesizes and outputs the signals output from each amplitude control circuit, which are input from the amplitude control section 3.

The receiving unit 5 measures the level of the signal input from the synthesizing unit 4 and determines the received level, that is, the RSSI (Res)
Control unit 6 as ceiving Signal Strength Indicator)
Is output to

The control unit 6 receives the RS input from the receiving unit 5
The instruction is output to the phase control unit 2 and the amplitude control unit 3 based on the SI. The control section 6 turns the variable gain relay amplifier 7 ON or OFF, and controls the gain of the variable gain relay amplifier 7. The operation of the control unit 6 will be described later in detail.

The variable gain relay amplifier 7 amplifies and outputs a signal input from the receiving unit 5. The transmitting antenna 8 radiates a signal output from the variable gain relay amplifier 7 to the outside.

The receiving section 5 may include a demodulation circuit, and may demodulate a signal input from the combining section 4. In this case, the variable gain relay amplifier 7 amplifies the demodulated signal, re-modulates and outputs it.

Here, the operation of the control unit 6 will be described with reference to FIG. FIG. 2 is a flowchart illustrating a specific process of the control unit 6.

The control unit 6 firstly includes a variable gain relay amplifier 7
Is turned off (S1). Then, the control unit 6 controls the phase control unit 2 and the amplitude control unit 3 while controlling the condition that the RSSI input from the reception unit 5 becomes maximum (the state of the phase control of each phase control circuit and the amplitude control unit). A state where the RSSI of the signal (desired wave) arriving at the first antenna 1 is maximized is detected (S2).

When the direction in which the RSSI of the signal (desired wave) arriving at the first antenna 1 is maximized is detected, the control unit 6 turns on the variable gain relay amplifier 7 (S3).
Then, while gradually increasing the gain of the variable gain relay amplifier 7, the direction in which the RSSI of the signal (interference wave) circulating from the second antenna 8 to the first antenna 1 is maximized in the same manner as in the process S2. It is detected (S4).

Then, the direction of the desired wave arriving at the first antenna 1 detected in the process S2 (hereinafter referred to as "desired wave direction")
On the basis of the direction of the interference wave arriving at the first antenna (hereinafter referred to as “interference wave direction”) detected in process S4, under the condition that the interference wave direction becomes a null point,
The phase control unit 2 and the amplitude control unit 3 are controlled so that the RSSI of the desired wave arriving at the first antenna 1 is maximized again (S5), and the process ends.

Here, the specific contents of the processing for maximizing the RSSI of the desired wave under the condition that the direction of the interference wave becomes a null point in the processing S2 to S5 will be described.

Here, for simplicity of explanation, a case where the number of elements of the receiving antenna is 2 will be described as an example. In the following description, the equivalent baseband complex signals of the desired wave and the wraparound wave received by the first antenna element are respectively represented by r11 and r12, and the desired wave and the interference wave received by the second antenna element are represented by r11 and r12. The equivalent baseband complex signals are r21 and r22, respectively. Here, the relative phase relationship between rll, r12, r21, and r22 can be estimated based on the desired wave direction obtained in step S2 and the interference wave direction obtained in step S4. Hereinafter, an example of the estimation method will be described.

The control unit 6 includes the phase control unit 2 and the amplitude control unit 3
Is set as w1 and w2, the desired wave component c1 and the interference wave component c2 at the output of the combining unit 4 are calculated by the following matrix of [Equation 1]. The relationship is expressed.

[0030]

(Equation 1)

In [Equation 1], the condition that the desired wave component is not zero and the interference wave component is zero, that is, c1 ≠ 0,
By solving for w1 and w2 with c2 = 0, the complex weighting coefficient (w
1, w2) can be obtained.

However, in reality, it is not possible to directly observe the elements of the matrix shown in [Equation 1]. Therefore, it is necessary to search for a set of w1 and w2 such that c2 = 0 by performing the processing of steps S2 to S4. And Here, since c2 is a signal radiated from the transmitting antenna 8 of the present apparatus, it is possible to estimate the level of c2 that has entered the receiving antenna 1 by mutual processing or the like.

In general, when w1 and w2 are not adjusted, the level of c2 greatly exceeds the level of c1, that is, it can be considered that the following equation (2) is satisfied.

[0034]

(Equation 2)

Therefore, in the processing S2 to S4, a set of w1 and w2 may be simply searched so that the level of the signal arriving at the receiving antenna 1 is minimized.

Even when the number of antenna elements is N, as can be easily analogized from this example, when the direction of the desired wave is different from the direction of the interference wave, the interference wave of the (N-1) wave is suppressed and the desired wave direction is suppressed. The coefficients w1, w2, ..., wN can be uniquely determined so as to receive only the waves.

According to the present apparatus, even if an interference wave goes around the receiving antenna, the control unit can suppress the interference wave and receive the desired wave. Even if the distance is shortened, there is an effect that wraparound interference waves can be suppressed.

[0038]

According to the first aspect of the present invention, a receiving antenna in which a plurality of antenna elements are arranged in an array is provided to detect a direction in which a signal from a base station arrives and a direction in which an interference wave arrives. Then, based on the direction, a weighting coefficient of the receiving antenna for suppressing the interference wave is calculated, and the weighting is performed to receive the signal, so that the wireless relay device receives the signal. Even if the distance is shortened, there is an effect that interference waves can be suppressed by weighting at the time of reception.

According to the second aspect of the present invention, the phase and amplitude of the signals arriving at each of the plurality of antenna elements arranged in an array are controlled by the corresponding phase control circuit and amplitude control circuit, respectively. A combining unit combines the controlled signals, and a receiving unit outputs the combined signal.
The level of the signal is output as a reception level, and the variable gain relay amplifier amplifies the signal input from the receiving unit with a specific gain, and transmits and outputs the signal via the transmitting antenna. With the variable repeater amplifier turned off, the phase control circuit and the amplitude control circuit are controlled, the condition at which the reception level input from the reception unit is maximized is checked, the direction in which the desired wave arrives is detected, and then the gain adjustment is performed. Turn on the relay amplifier, gradually increase the amplification gain, control the phase control circuit and the amplitude control circuit, check the condition that the reception level input from the receiving unit is maximum, and check the arrival direction of the interference wave. And a weighting coefficient for suppressing the interference wave is calculated based on the detected directions, and the wireless relay device controls the phase control circuit and the amplitude control circuit according to the weighting coefficient. Be shortened to use the antenna the distance between the transmitting antenna, there is an effect capable of suppressing the interference wave by the weighting at the time of reception.

[Brief description of the drawings]

FIG. 1 is a configuration block diagram of the present apparatus.

FIG. 2 is a flowchart illustrating a specific process of a control unit 6;

FIG. 3 is a perspective view showing a specific appearance of the receiving antenna 1;

[Description of Signs] 1 ... Reception antenna, 2 ... Phase control unit, 3 ... Amplitude control unit, 4 ... Synthesis unit, 5 ... Reception unit, 6 ... Control unit, 7
... Variable gain relay amplifier, 8 ... Transmission antenna

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Yoshio Ebine 2-10-1 Toranomon, Minato-ku, Tokyo Inside NTT Mobile Communication Network Co., Ltd. (72) Inventor Kazuto Ito Toranomonji, Minato-ku, Tokyo Chome 10-1 NTT Mobile Communication Network Co., Ltd.

Claims (4)

[Claims] A receiving antenna having a plurality of antenna elements arranged in an array, detecting a direction in which a signal from a base station arrives and a direction in which an interference wave arrives, and detecting an interference wave based on the directions. A wireless relay apparatus that calculates a weighting coefficient of the receiving antenna that suppresses a signal, performs weighting, and receives a signal. 2. A receiving antenna in which a plurality of antenna elements are arranged in an array, a phase control circuit provided corresponding to the antenna element and controlling a phase of a signal arriving at the corresponding antenna element, An amplitude control circuit provided corresponding to the control circuit, for controlling the amplitude of the signal input from the corresponding phase control circuit, a synthesis unit for synthesizing the signal input from the amplitude control circuit, and an input from the synthesis unit And a variable gain repeater amplifier that amplifies a signal input from the receiver with a specific gain, and a signal input from the variable gain repeater amplifier. The transmitting antenna that radiates the signal to be transmitted and the variable gain repeater amplifier are initially turned off, and the signal arriving at the receiving antenna is set to only the desired signal, Control the control circuit and the amplitude control circuit, check the condition that the reception level input from the receiving unit is maximum, detect the direction of arrival of the desired wave, then turn on the variable gain relay amplifier, While gradually increasing the gain of the amplification, controlling the phase control circuit and the amplitude control circuit, to check the condition that the reception level input from the receiving unit is maximum, to detect the arrival direction of the interference wave, Based on the arrival direction of the desired wave and the arrival direction of the interference wave, calculate a weighting coefficient of the receiving antenna for suppressing the interference wave, and a phase control circuit to receive the desired wave according to the weighting coefficient. And a control unit for controlling the amplitude control circuit. 3. The receiving unit demodulates an input signal and outputs the demodulated signal to a variable gain relay amplifier. The variable gain amplifier remodulates a signal input from the receiving unit and outputs a specific gain. 3. The radio relay apparatus according to claim 2, wherein the radio relay apparatus is a variable gain relay amplifier that amplifies the signal and radiates the same via a transmission antenna. 4. A receiving section for outputting an input signal to a variable gain relay amplifier without demodulating the signal, wherein the variable gain amplifier amplifies a signal input from the receiving section with a specific gain. 3. The radio relay apparatus according to claim 2, wherein the radio relay apparatus is a variable gain relay amplifier that radiates the signal via a transmission antenna as it is.