JP4568360B2 - Repeater device - Google Patents

Description

  The present invention relates to an interference signal suppression technique for suppressing an interference signal caused by sneaking into a reception antenna, which occurs when a transmission signal is radiated at the same frequency as a reception signal, for example, and a repeater apparatus having an interference signal suppression function. The repeater device is a communication device used for relaying wireless communication, and may be called a relay device or a wireless relay booster.

  Repeater devices are used to improve radio wave conditions in buildings, tunnels, and mountainous areas where radio base station radio waves are difficult to reach. Since the repeater apparatus amplifies the received signal with a predetermined gain and transmits it, there is no need to install a dedicated line unlike a radio base station, and there is an advantage that the cost can be reduced in terms of equipment. However, since the reception signal and the transmission signal have the same frequency, if a part of the transmission signal goes around the reception antenna, this signal becomes an interference signal, and oscillation occurs when the gain of the amplifier (called retransmission gain) is large. There is a problem of causing.

  In this case, a method of physically separating the transmission antenna and the reception antenna to reduce the coupling amount between the antennas may be considered, but this method may increase the installation scale of the repeater device and may be difficult to implement. There is a problem in terms of versatility.

  As another method, a signal obtained by adding a predetermined delay time corresponding to a delay time of one chip or more in a CDMA (Code Division Multiple Access) signal to a reception signal is output as a transmission signal, and in a delay time when an interference signal arrives, Suppression generated by detecting the residual component of the interference signal by performing a correlation operation between the received signal and the transmitted signal, and having the opposite phase, the same amplitude, and the same delay with respect to the interference signal based on the detected residual component There is a technique for canceling an interference signal generated when a transmission signal wraps around a reception antenna by a signal (see, for example, Patent Document 1).

  In this technique, when performing a correlation operation between a received signal mixed with an interference signal and a transmission signal to be retransmitted to detect a residual component of the interference signal, a delay time of one chip or more in the CDMA signal is added to the transmission signal. Therefore, there is a merit that the correlation between the signal other than the correlation between the transmission signal serving as the reference signal and the residual component of the interference signal becomes low, and the residual component can be detected with high accuracy. However, when the sneak interference signal suppression processing of the repeater device is digitized for the purpose of downsizing the entire device, the resolution with respect to the delay amount of the suppression signal is the reciprocal of the frequency (sampling frequency) of the operation clock during digital processing. Since it is determined by a certain unit time width, it is difficult to completely match the delay of the suppression signal with the delay of the interference signal, and as a result, the amount of suppression of the interference signal is deteriorated. .

In response to this problem, there has been proposed an interference signal suppression device that does not reduce the suppression amount of the interference signal due to the wraparound of the transmission signal to the reception antenna even when the interference signal suppression of the repeater device is performed by digital processing (for example, a patent Reference 2).
In this interference signal suppression device, two or more suppression signals are generated in the vicinity of a desired interference signal for the detected interference signal, and the interference signal is suppressed by this suppression signal. Accordingly, there is an effect that it is possible to improve the suppression amount of the interference signal even when the completely same delay amount cannot be set due to the delay increment determined from the sampling frequency of the digital signal processing unit.

In the repeater apparatus having the above suppression function, the isolation between the receiving antenna and the transmitting antenna (antenna isolation) is measured with a measuring instrument (for example, a network analyzer) in the antenna installation state, and a desired signal (D wave) The ratio (DU ratio) of the interference signal (unnecessary wave: U wave) with respect to the signal, the amplification factor setting of the repeater device, and the suppression amount of the interference wave were confirmed.
JP 2001-196994 A JP 2005-39336 A

  As described above, when using a conventional repeater device having an interference signal suppression function, in order to know the distribution state, signal strength, antenna isolation, etc. of the interference signal, a special measuring instrument such as a network analyzer is used. Therefore, there is a problem that the repeater device cannot be easily installed.

  This invention makes it the subject to provide the repeater apparatus which can grasp | ascertain the distribution state of an interference signal easily, without using a special measuring device.

The repeater apparatus according to the present invention receives a reception signal in which an interference signal is mixed into a desired signal from a reception antenna, generates a suppression signal for suppressing the interference signal from the reception signal, and receives the generated suppression signal. In the repeater device having a function of suppressing the interference signal by adding the signal and an adder and further outputting the signal in which the interference signal is suppressed from the transmission antenna as a transmission signal, by changing the attenuation amount A variable attenuator for increasing / decreasing the signal strength of the transmission signal, and comparing the signal strength of the input side and the output side of the adder while changing the signal strength of the transmission signal with the variable attenuator, The device gain is increased until it is detected, and further, correlation integration is performed while the delay time is sequentially changed to the received signal. The presence / absence of an interference signal and the delay time of the interference signal are detected. Based on the detected information and the attenuation amount of the variable attenuator at the time of detection, which interference signal has a signal strength ratio of what level A delay profile that indicates whether the delay time is distributed is generated, the generated delay profile is stored, and control means for displaying the stored delay profile on a predetermined display device is provided.
With such a configuration, the state of the interference signal can be grasped only by the repeater device without using a measuring instrument, and the distribution of the interference signal can be confirmed by the display device.

  In one embodiment, the control means determines that the state is a state immediately before oscillation when detecting a state in which a difference in signal strength between the input side and the output side of the adder reaches a predetermined ratio. The variable attenuation amount in the state and the signal strength of the received signal are stored as one of the delay profiles.

In another embodiment, the control means obtains a ratio of the signal strength of the interference signal to the signal strength of the desired signal based on the delay profile acquired immediately before the oscillation and the device gain when the suppression operation is completed, Data representing the ratio as a true or logarithm, or data obtained by adding the attenuation amount of the variable attenuator to the ratio is stored as one of the delay profiles.
Alternatively, the control means derives the antenna isolation based on the delay profile obtained immediately before the oscillation, and stores the antenna isolation as one of the delay profiles.
In these cases, the control means, for example, repeats the operation of detecting the amplitude and phase of the interference signal from the received signal while changing the delay time after increasing the device gain until the state just before the oscillation. The delay profile is generated.

  In another embodiment, the control means stores either a delay profile before the suppression operation for the interference signal or a delay profile after the interference signal suppression operation, and a newly stored delay profile and a new one. By mapping the generated delay profile to predetermined graph data, information indicating the degree of suppression of the interference signal is visualized on the display device. As a result, the distribution state of the interference signal can be grasped more intuitively.

  In another embodiment, the control means measures in advance how much the signal strength of the interference signal with respect to the desired signal can be handled as no deterioration of the desired signal, and the measurement result is the graph data. Is drawn as a threshold value on the graph displayed by the above, and the degree of suppression of the interference signal can be confirmed by visualizing the delay profile after the suppression operation and the threshold value together. Thereby, not only the distribution state of the interference signal but also the degree of suppression of the interference signal can be intuitively grasped.

  According to the present invention, since the delay profile can be easily grasped from the display device, the distribution state of the interference signal with respect to the desired signal can be grasped without using a special measuring instrument.

Hereinafter, embodiments of the present invention will be described.
FIG. 1 is a schematic diagram of a communication system to which the present invention is applied. This communication system includes a base station 11, a repeater device 12, and a terminal 14. The repeater device 12 is installed in a place where the radio wave condition is not preferable, such as a building or other building 13a, 13b flooded.

  The repeater device 12 of this embodiment shall radiate | transmit via a transmission antenna at the same frequency as the electromagnetic wave (received signal) received with the receiving antenna. In such a repeater device 12, all of the radio waves (transmission signals) transmitted from the transmission antenna do not reach the terminal 14, and some of them reach the reception antenna directly from the transmission antenna. ((1) in the figure), a part is reflected by the buildings 13a and 13b and then arrives at the receiving antenna ((2) and (3) in the figure), and these signals become interference signals.

  In general, when suppressing an interference signal, the delay time and amplitude of the interference signal are detected from the received signal, and a suppression signal having the same phase as that of the detected interference signal and the same amplitude as the interference signal is detected. By combining with the received signal, the interference signal can be canceled.

[Repeater device]
As shown in FIG. 2, the repeater device 12 includes base station antenna 21, antenna duplexer 22, terminal antenna 23, and downlink and uplink components, ie, low noise amplifiers 24 a and 24 b. , Frequency converters 25a, 25b, 25c, 25d, interference signal suppression devices 26a, 26b, and high-power amplifiers 27a, 27b.

  The base station antenna 21 is an antenna for transmitting / receiving radio signals to / from the base station 11, and the terminal antenna 23 is an antenna for transmitting / receiving radio signals to / from the terminal 14. Each functions as a transmission antenna at the time of transmission, and functions as a reception antenna at the time of reception.

  The antenna duplexer 22 supplies an analog reception signal received from the base station 11 via the base station antenna 21 to the downlink, and transmits an analog transmission signal from the uplink transmitted to the base station 11 to the base station. The signal is supplied to the station antenna 21. In addition, the reception signal received from the terminal 14 via the terminal antenna 23 is supplied to the uplink, and the transmission signal from the downlink transmitted to the terminal 14 is supplied to the terminal antenna 23.

  The low noise amplifiers 24a and 24b are low noise and high gain amplifiers that amplify weak radio waves received via the base station antenna 21 or the terminal antenna 23. In this embodiment, since the received signal uses high frequencies of 800 [MHz] and 2 [GHz] bands, the received signal is frequency-converted to an intermediate frequency by the frequency converters 25a and 25c. The signal before conversion is called an RF signal, and the signal after conversion is called an IF signal. The frequency converters 25c and 25d convert the IF signal into an RF signal by performing the reverse process to the above during transmission. The high-power amplifiers 27a and 27b are high-amplification amplifiers that amplify transmission waves.

  The external control and display device 28 controls the interference signal suppression devices 26a and 26b from the outside, and is configured by a device such as a computer having a display function. This will be described in detail later.

[Interference signal suppressor]
Next, the interference signal suppression devices 26a and 26b will be described in more detail.
The interference signal suppression devices 26a and 26b are the same, and are configured as shown in FIG. 3, for example. That is, the interference signal suppression devices 26a and 26b generate the A / D converter 31, the chip delay unit 32, the D / A converter 43, the adder 34, and suppression signals for suppressing the interference signals, respectively. A plurality of phase amplitude controllers 35a, 35b, 35c, a plurality of correlation integrators 36a, 36b, 36c, a plurality of delay units 37a, 37b, 37c, and a monitoring control circuit 38.

  Each of the phase amplitude controllers 35a, 35b, 35c, the correlation integrators 36a, 36b, 36c and the delay units 37a, 37b, 37c forms a pair to suppress the interference signal that appears in the delay time. The suppression signal is generated. That is, the phase amplitude controllers 35a, 35b, and 35c, the correlation integrators 36a, 36b, and 36c, and the delay units 37a, 37b, and 37c are each a suppression signal for suppressing one interference signal as a set. Is generated.

  The A / D converter 31 converts the analog signal sent from the previous stage into a digital signal at a predetermined sampling frequency. In the following description, the digitally converted signal is referred to as “digital received signal” for convenience. This digital received signal is a signal in which a desired signal and an interference signal are combined. The digital received signal is input to the chip delay unit 32 through the adder 34, and a plurality of copies are copied and distributed to the correlation integrators 36a, 36b, and 36c, respectively.

  The D / A converter 43 is a converter having the reverse effect of the A / D conversion device 31 and converts the digital signal processed by the chip delay device 32 into an analog signal. The converted signal is output from the transmission antenna as a transmission signal.

  The chip delay unit 32 adds a delay of one or more chips of the CDMA signal at the time of retransmission in order to reduce the correlation between the digital received signal having a desired signal component and the interference signal that circulates from the transmitting antenna to the receiving antenna. Device (delay circuit). A signal output from the chip delay unit 32 is input to the D / A converter 43. A plurality of signals having the same amplitude and phase each include a signal component (amplitude and phase component) of the digital reception signal. As a signal, it is taken into delay devices 37a, 37b, and 37c.

  The delay units 37a, 37b, and 37c output the reference signals that have been fetched by delaying them by a time set by the CPU 40 (hereinafter, it is necessary to particularly distinguish the delayed reference signals from the normal reference time). If there is, it is referred to as a “delayed reference signal”). The set time for delaying can be appropriately updated by the CPU 40 in each of the delay devices 37a, 37b, and 37c.

  Correlation integrators 36a, 36b, and 36c respectively perform correlation integration between the delayed reference signal and the digital reception signal in parallel with other correlation integrators. At this time, the delay amounts (delay times) in the correlation integration of the individual correlation integrators 36a, 36b, and 36c are different. By doing so, the correlation calculation is performed with a delay time that matches the delay of the interference signal to be detected. The result of the correlation integration is a correlation integration value that represents the degree of correlation with the interference signal, and the larger this value is, the higher the possibility that the delayed reference signal is more suitable for the interference signal, that is, the interference signal. That is, when the interference signal is mixed in the digital received signal, a strong correlation is obtained (for example, the signal strength is increased), and when there is no interference signal, the correlation cannot be obtained. A delayed reference signal having a large value can be detected as a signal corresponding to an interference signal.

  However, since it is necessary to know the delay time of the interference signal in advance in order for the correlation operation to function effectively, it corresponds to each of the correlation integrators 36a, 36b, 36c and the phase amplitude controllers 35a, 35b, 35c. Delay devices 37a, 37b, and 37c are provided. The set time for delaying is a time corresponding to the delay time of the interference signal. As a method for detecting the delay time, the supervisory control circuit 38 performs a correlation operation by varying the delay time for each unit time which is the reciprocal of the sampling frequency at the time of digital signal processing, and a correlation is obtained at a delay time with an interference signal. The delay time of the interference signal is detected by utilizing the fact that no correlation can be obtained with the delay time without the interference signal.

  The phase / amplitude controllers 35a, 35b, and 35c correspond to the delayed reference signal corresponding to the interference signal in a one-to-one correspondence with the amplitude of the delayed reference signal multiplied by a predetermined coefficient, and a suppression signal having an opposite phase is obtained. The generated suppression signal is output at the same timing as the time when the corresponding delayed reference signal is output (the time detected by the correlation integration). This timing is actually represented by a delay time. The adder 34 adds the suppression signal generated by each or any of the phase amplitude controllers 35a, 35b, and 35c to the digital reception signal.

The variable attenuator 42 adjusts the amount of attenuation and controls the output level of the transmission signal.
The monitoring control circuit 38 includes a correlation integrator 39, a CPU 40, a memory 44, and a delay device 41.
The delay device 41 is a component having the same function as the delay devices 37 a, 37 b, and 37 c, and delays the reference signal and inputs it to the correlation integrator 39.
The correlation integrator 39 is a component having the same function as the above-described correlation integrators 36a, 36b, and 36c, and correlates the reference signal delayed by the delay unit 41 with the digital received signal obtained by synthesizing the desired signal and the interference signal. The amplitude and phase of the interference signal are detected by integration. The detected amplitude and phase information of the interference signal is output to the CPU 40.

  The CPU 40 functions as control means for suppressing interference signals by reading and executing a predetermined computer program. Specifically, the CPU 40 associates the delay time with the amplitude and phase information of the interference signal, and sets the delay time of the interference signal detected by the correlation integrator 39 in each of the delay devices 37a, 37b, and 37c. Each interference signal is associated with a suppression signal for suppressing one interference signal. The CPU 40 also has a delay profile, that is, information indicating a relative relationship between a desired signal (D wave) and an interference signal (U wave) (a DU ratio indicating a ratio of the signal intensity of the U wave to the signal intensity of the D wave, transmission / reception) Processing for derivation of antenna isolation, signal strength comparison graph, etc., which varies depending on the antenna interval, and storage of processing results in the memory 44 and external control and output control to the display device 28 are performed. The memory 44 stores a delay profile such as a delay time, a correlation calculation result by the correlation integrator 39, and an attenuation amount when the variable attenuator 42 is controlled by the CPU 40.

  The delay units 37a, 37b, 37c, 41, the correlation integrators 36a, 36b, 36c, 39, and the phase amplitude controllers 35a, 35b, 35c are synchronized with a clock signal supplied from a clock generator (not shown). . When this clock signal is input to the A / D converter 31, it functions as a sampling clock. Further, the delay unit 41 sets a delay amount corresponding to the clock signal in the reference signal, and supplies this to the correlation integrator 39 as a delayed reference signal.

  The external control and display device 28 is a computer that is communicably connected to the CPU 40, and controls the interference signal suppression devices 26 a and 26 b from the outside, and acquires interference signal suppression results and control information from the CPU 40. Display on the display.

[Operation of interference signal suppressor]
Next, the operation of the interference signal suppression devices 26a and 26b will be described.
FIG. 5 is an explanatory diagram of a control procedure for detecting an interference signal included in the received signal and suppressing the detected interference signal in the interference signal suppression devices 26a and 26b. Control by this procedure is performed by the CPU 40.
In FIG. 5, when the interference signal suppression devices 26a and 26b detect the presence of the interference signal, first, after maximizing the attenuation amount of the variable attenuator 42 (step S101), the device gain is increased to immediately before the oscillation. (Step S102), a delay profile is obtained by correlation calculation (Step S103).

Next, the peak value of the signal strength of the interference signal is detected from the acquired delay profile (step S104). It is determined whether or not the peak value exceeds a predetermined threshold value. If the peak value exceeds the predetermined threshold value (step S105: YES), the phase amplitude controllers 35a, 35b, and 35c have the same amplitude and opposite phase as the interference signals. The suppression signal is generated, and this suppression signal is added to the interference signal by the adder 34, thereby suppressing the interference signal (step S106).
On the other hand, if the peak value of the signal strength of the interference signal is equal to or less than the threshold value (step S105: NO) and the variable attenuation is not 0 (step S107: NO), the processing from step S102 to step S105 is performed by the apparatus. Repeat until the gain is maximized.

The detection of the state immediately before oscillation in step S102 will be described in more detail.
In obtaining the delay profile, the variable attenuator 42 is controlled to increase the detection accuracy, and the repeater device (analog circuit such as the high-power amplifiers 27a and 27b) starts oscillating by the interference signal included in the digital reception signal. A device gain immediately before, that is, a gain immediately before oscillation is detected.

FIG. 6 shows an example of a detection circuit for the gain just before oscillation.
It is well known that when the interference signal suppression device is not operated, oscillation occurs when the device gain is increased beyond the antenna isolation. Therefore, in this embodiment, the variable attenuator 42 of the interference signal suppressing device 26 is first set to the maximum attenuation amount so that the repeater device does not oscillate, and then the preceding stage (point A) and the succeeding stage (point B) of the adder 34. ), Gradually increase the device gain. By gradually reducing the attenuation amount of the variable attenuator 42, the device gain increases. When the attenuation amount becomes zero, the device gain becomes maximum.

When there is no interference signal, the previous stage (point A) is only the input signal and is therefore always constant. However, when an interference signal is mixed, if the device gain exceeds the antenna isolation, the repeater device may oscillate due to feedback of the input signal. In the state before the oscillation, the signal intensity at the front stage (point A) gradually increases due to the interference signal. However, as the oscillation phenomenon approaches, the signal intensity at the front stage (point A) increases with respect to the subsequent stage (B point). Point) signal strength increases rapidly. Therefore, in the process of gradually decreasing the attenuation amount of the variable attenuator 42, the signal intensity at the front stage (point A) and the rear stage (point B) of the adder 34 is monitored, and this difference becomes a certain ratio. When a state is detected, the detected state can be determined as a state immediately before oscillation.
In this embodiment, the information immediately before the oscillation is stored in the memory 44, and this information is used in the process of interference signal suppression and the process of creating the delay profile.

In each of the above processes, the delay profile is output from the interference signal suppression devices 26a and 26b (CPU 40) and displayed on the external control and display device 28. Therefore, the status of the interference signal can be easily confirmed without using a measuring instrument or the like.
Hereinafter, the contents of the delay profile will be specifically described.

[Delay Profile]
After raising the device gain to just before the oscillation, the CPU 40 sequentially sets the delay time of the delay unit 41 and performs a correlation operation in the correlation integrator 39, so that the desired signal and the interference signal are combined. Detect the amplitude and phase of the interference signal. This operation is repeated while changing the delay time set in the delay device 41 to create a delay profile. This delay profile is stored in the memory 44. The external control and display device 28 reads this delay profile and displays it on the display.

  FIG. 4A is a graph showing a display example of a delay profile. As shown in FIG. 4A, when the correlation calculation is performed by the correlation integrator 39, the desired signal itself is also detected. Therefore, in the delay profile, the delay time is “0” and the correlation value is “1”. There is also a signal.

[DU ratio]
The DU ratio (correlation value) is the ratio of the interference signal (U wave) to the desired signal (D wave) based on the device gain and antenna isolation at the time of completion of the suppression operation, as shown in the following equation (1). Can show. For example, when the final gain of the repeater device is 100 [dB] and the antenna isolation is [80 dB], the DU ratio is −20 [dB].

DU ratio [dB]
= Antenna isolation [dB] -device gain [dB] (1)

In the graph data of the delay profile shown in FIG. 4A, the horizontal axis is represented by the delay time, and the vertical axis is the correlation value (interference signal (U) when the signal intensity of the desired signal (D wave) is “1”. Relative ratio of wave): 0-1). The delay time on the horizontal axis has a unit time determined by the reciprocal of the sampling frequency as a minimum unit. In this graph, relative information such as how much delay time the interference signal (U wave) is generated with respect to the desired signal (D wave) and what signal intensity is mapped is mapped. Usually, among interference signals (U waves), a direct sneak interference signal between antennas is observed with the largest correlation value.
When correlation calculation is performed by the correlation integrator 39, the desired signal (D wave) also detects itself having a delay time of “0”, so that there is also a signal with a correlation value of “1”.

  The acquisition of the data necessary to describe the graph data of FIG. 4A prevents the occurrence of oscillation by increasing the device gain more than the antenna isolation, for example, without the suppression operation, In order to increase the detection accuracy, the device gain is increased from the maximum attenuation state to the state immediately before oscillation by controlling the variable attenuator 42.

  The DU ratio varies from measurement to measurement depending on the antenna isolation and the surrounding environment due to the gain immediately before oscillation. Therefore, if the DU ratio is derived as a correlation value (data represented by a true scale of 0 to 1.0), what is the DU ratio when the device gain is maximized directly from the state immediately before oscillation? Cannot be grasped correctly. Therefore, in the present embodiment, the attenuation amount of the variable attenuator 42 is added to the correlation value, and the amplification degree of the apparatus is reflected in the calculation result, whereby the DU ratio is expressed as an absolute value (data represented on a logarithmic [dB] scale). ), So that it can be displayed. The DU ratio (absolute value) can be obtained by the following equation (2) from the attenuation amount and the correlation value of the repeater device immediately before the oscillation.

DU ratio (absolute value) [dB]
= Device attenuation-20log (correlation value) (2)

For example, when the final gain of the device is 100 [dB] and the device attenuation of the repeater device immediately before oscillation (attenuation by the variable attenuator 42) is −30 [dB] (device gain 70 [dB]), the desired value is obtained. An example in which the correlation value of the interference signal (U wave) is detected as “0.4” with respect to the correlation value “1” of the signal (D wave) will be described. “20 × log (0.4)” on the right side of Expression (2) at this time is −8 [dB], and the interference signal (U wave) is 8 [dB] lower than the desired signal (D wave). State. Then, according to equation (2), the DU ratio is as follows.
−30− (20) × log (0.4) = − 22 [dB]

On the other hand, the antenna isolation is as follows from the equation (1).
Antenna isolation [dB]
= 8 [dB] +70 [dB]
= 78 [dB]
Therefore, when the suppression operation is completed and the device gain becomes 100 [dB], the DU ratio becomes 78 [dB] -100 [dB] (= −22 [dB]) from the equation (1), and the equation ( It agrees with the value obtained in 2).

  In this way, the absolute value of the DU ratio is calculated by calculating the attenuation value of the repeater device immediately before oscillation (attenuation amount by the variable attenuator 42) with the correlation value between the desired signal (D wave) and the interference signal (U wave). Can be expressed logarithmically. This DU ratio is transferred from the interference signal suppression devices 26a and 26b to the external control and display device 28 and displayed.

[Antenna isolation]
The antenna isolation of the repeater device is obtained by detecting the peak value of the interference signal from the delay profile, specifying the direct interference signal between the antennas, and calculating the device gain and the DU ratio obtained as described above. Can do. The calculation result can be displayed by the external control and display device 28.

[Graph data]
By mapping the delay profile acquired before and after suppressing the interference signal to one graph data, it can be visualized. Usually, since the desired signal (D wave) is itself, it is not displayed, and actual graphs are as shown in FIG. 4 (b) and FIG. 4 (c).
The DU ratio before the suppression operation is displayed when the gain immediately before oscillation is detected and stored in the monitor control circuit 38 or the internal memory 44. Then, this is read out after the suppression operation, or is subsequently output to the external control and display device 28 and displayed on the same graph, thereby confirming the suppression amount of the DU ratio and the interference signal (U wave). Is possible.

  In the graph data of FIG. 4B, the DU ratio (correlation value) is displayed on the vertical axis as a relative value on a logarithmic scale while the DU ratio (absolute value) is displayed on a logarithmic scale. Here, it is measured in advance how much the interference signal (U wave) can be handled with respect to the desired signal (D wave) if there is no degradation of the desired signal (D wave). It draws as a threshold value. A delay profile is also drawn after the suppression processing, and this delay profile is compared with a threshold value on a comparison graph so that it can be confirmed that the delay profile is below the threshold value. Thereby, it is possible to visually confirm that the interference signal suppression operation has been normally performed and the level of suppression at that time.

  In the graph data of FIG. 4C, the vertical axis represents the DU ratio on a logarithmic scale only. From this graph, it is possible to visually confirm the DU ratio between the interference wave before the suppression operation and the interference wave level after suppression, and the suppression amount of the interference signal after suppression.

  In the graph data of FIG. 4B, the logarithmic scale is used, so that even the portion where the correlation value of the interference wave amount after suppression is “0.1” or less can be displayed finely as the DU ratio.

As described above, in this embodiment, the delay profile in the repeater device 12 is displayed on the external control and display device 28, so that it is possible to easily grasp the distribution state of the interference signal without using a special measuring instrument. .
In the present embodiment, information on the signal strength of the interference signal for each delay time is used as the delay profile. However, any other information can be used as long as it represents the distribution state of the interference signal. Such information, for example, the delay time of the U wave with respect to the D wave, the suppression amount of the U wave, etc. can also be used as the delay profile.

BRIEF DESCRIPTION OF THE DRAWINGS Outline explanatory drawing of the communication system containing the repeater apparatus of this invention. The figure which shows the structural example of the repeater apparatus by this embodiment. The figure which shows the structural example of an interference signal suppression apparatus. (A) is a figure which shows a delay profile, (b) is graph data which shows the comparative example of the interference signal before and behind suppression, (c) is a figure which shows the example of a delay profile different from (b). Explanatory drawing of the suppression process procedure of an interference signal. The figure which shows the structural example for detecting the gain just before an oscillation.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 11 ... Base station, 12 ... Repeater apparatus, 13a, 13b ... Building, 14 ... Terminal, 21 ... Antenna for base stations, 22 ... Antenna duplexer, 23 ... Antenna for terminal, 24, 24a, 24b ... Low noise amplifier, 25, 25a, 25b, 25c, 25d ... Frequency converter, 26, 26a, 26b ... Interference signal suppression device, 27a, 27b ... High output amplifier 28 ... External control and display device 31 ... A / D converter 32 ... Chip delay device 34 ... Adder 35a, 35b, 35c ... Phase amplitude Controller, 36a, 36b, 36c, 39 ... correlation integrator, 37a, 37b, 37c, 41 ... delay unit, 38 ... monitoring control circuit, 40 ... CPU, 42 ... variable attenuation , 43... D / A converter.

Claims (7)

A reception signal in which an interference signal is mixed into a desired signal is received from a reception antenna, a suppression signal for suppressing the interference signal is generated from the reception signal, and the generated suppression signal is added to the reception signal by an adder. In the repeater device having a function of suppressing the interference signal by this, and further outputting a signal in which the interference signal is suppressed as a transmission signal from a transmission antenna,
A variable attenuator that increases or decreases the signal strength of the transmission signal by changing the amount of attenuation;
By comparing the signal strength of the input side and the output side of the adder while changing the signal strength of the transmission signal with this variable attenuator, the device gain is increased until a state immediately before oscillation is detected, and further The presence or absence of an interference signal to the received signal and the delay time of the interference signal are detected by performing correlation integration while sequentially varying the delay time, and based on the detected information and the attenuation amount of the variable attenuator at the time of detection Then, a delay profile is generated that indicates in what delay time the interference signal having a signal strength ratio with respect to the desired signal is distributed, and the generated delay profile is stored, and the stored delay profile is determined in advance. And a control means for displaying on the display device.
Repeater device. The control means determines that the state is a state immediately before oscillation when detecting a state in which a difference in signal strength between the input side and the output side of the adder becomes a predetermined ratio, and the variable attenuator in the state immediately before oscillation And the received signal strength of the received signal as one of the delay profiles,
The repeater apparatus according to claim 1. The control means obtains a ratio of the signal strength of the interference signal to the signal strength of the desired signal based on the delay profile acquired immediately before the oscillation and the device gain at the time of completion of the suppression operation, and this ratio is expressed as a true or logarithm. Storing the represented data or data obtained by adding the attenuation amount of the variable attenuator to the ratio as one of the delay profiles;
The repeater apparatus according to claim 2. The control means derives the antenna isolation based on a delay profile obtained immediately before the oscillation, and stores the antenna isolation as one of the delay profiles.
The repeater apparatus according to claim 3. The control means generates the delay profile by repeating the operation of detecting the amplitude and phase of the interference signal from the received signal after changing the delay time after increasing the device gain until the state just before the oscillation. To
The repeater apparatus according to claim 3 or 4. The control means stores either a delay profile before the suppression operation for the interference signal or a delay profile after the suppression operation of the interference signal, and a previously stored delay profile and a newly generated delay profile, By mapping the information to predetermined graph data, the information indicating the degree of suppression of the interference signal is visualized on the display device.
The repeater device according to any one of claims 1 to 5. The control means measures in advance how much the signal strength of the interference signal with respect to the desired signal can be handled as no deterioration of the desired signal, and the measurement result is displayed on a graph displayed by the graph data. Drawing as a threshold, and by visualizing the delay profile after the suppression operation and the threshold together, it is possible to confirm the degree of suppression of the interference signal,
The repeater apparatus according to claim 6.

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