WO2016076054A1

WO2016076054A1 - Antenna system

Info

Publication number: WO2016076054A1
Application number: PCT/JP2015/079013
Authority: WO
Inventors: 仁士平田; 麗岳
Original assignee: 住友電気工業株式会社
Priority date: 2014-11-10
Filing date: 2015-10-14
Publication date: 2016-05-19
Also published as: JP2016092715A; JP6476770B2

Abstract

An antenna system 3 is provided with: a divider 13 which divides an analog transmission signal into a plurality of transmission signals; a plurality of power amplifiers 16 which amplify the plurality of transmission signals divided by the divider 13; a plurality of antenna elements 5 which transmit the plurality of transmission signals amplified by the plurality of power amplifiers 16; and a first phase shifter 15 provided between the divider 13 and the plurality of power amplifiers 16 to adjust the phases of the plurality of transmission signals divided by the divider 13.

Description

Antenna system

The present invention relates to an antenna system used for a base station apparatus or the like of a wireless communication system.

2. Description of the Related Art An antenna system in which an array is configured of a plurality of antenna elements is conventionally used in a base station apparatus in a wireless communication system such as a mobile phone.
In the above-mentioned conventional antenna system, the tilt angle may be made variable by adjusting the phase of the signal transmitted / received from each antenna element (for example, refer to nonpatent literature 1).

The antenna system of the base station apparatus described in Non-Patent Document 1 described above is configured to control the phase for each sub-array in which a predetermined number of antenna elements are one unit.
An example of an antenna system configured to control phase per subarray is shown in FIG.

In FIG. 8, antenna system 100 is connected to power divider 102 to which the transmission signal amplified by power amplifier 101 is applied, a plurality of phase shifters 103 connected to power divider 102, and phase shifter 103. And a plurality of antenna elements 104 being provided.
The phase shifter 103 has a function of adjusting the phase of the transmission signal supplied from the power distributor 102 based on an external control command.

Each phase shifter 103 is connected to a predetermined number (three in the illustrated example) of antenna elements 104. Therefore, in the antenna system 100, transmission signals from a predetermined number of antenna elements 104 connected to the same phase shifter 103 are adjusted to have the same phase by the same phase shifter 103, respectively. That is, the predetermined number of antenna elements 104 connected to the same phase shifter 103 constitute a sub-array 105.

Here, since the antenna system 100 adjusts the phase of the transmission signal for each sub-array 105, the array spacing is substantially wider than the spacing between adjacent antenna elements. Therefore, setting the tilt angle relatively large can be obtained by individually adjusting the phase condition of the transmission signal actually transmitted from each antenna element and the phase of the transmission signal of each of the plurality of antenna elements. The deviation from the ideal phase condition becomes large, and deterioration of the transmission characteristics such as increase of side lobes and decrease of gain occurs.

Therefore, for example, it is conceivable to provide a phase shifter corresponding to each of the antenna elements 104.
However, since the phase shifter 103 adjusts the phase of the relatively large power transmission signal amplified by the power amplifier 101, a large phase shifter corresponding to the large power is used as the phase shifter 103.
Providing such a large phase shifter 103 for each antenna element 101 is difficult from the viewpoint of securing the installation space, and in the antenna system 100, the number of the phase shifters 103 can be installed is limited. Had the problem of being

The present invention has been made in view of such circumstances, and it is an object of the present invention to provide an antenna system that can suppress the installation of a phase shifter from being restricted.

An antenna system according to one embodiment includes: a distributor that divides an analog transmission signal into a plurality; a plurality of first amplifiers that amplify the plurality of transmission signals distributed by the distributor; and the plurality of first amplifiers A plurality of antenna elements for transmitting the plurality of transmission signals amplified by the plurality of antennas, the distributor, and the plurality of first amplifiers, and the phases of the plurality of transmission signals distributed by the distributor And a first phase shifter for adjusting.

In one embodiment, an antenna system includes a plurality of antenna elements for receiving an analog reception signal, a plurality of amplifiers for amplifying the plurality of reception signals received by the plurality of antenna elements, and the plurality of amplifiers A phase shifter provided between a combiner for combining a plurality of amplified received signals, the plurality of amplifiers, and the combiner and performing phase adjustment of the plurality of received signals amplified by the plurality of amplifiers. And a vessel.

ADVANTAGE OF THE INVENTION According to the antenna system of this invention, it can suppress that the installation of a phase shifter is restricted.

It is a figure which shows a part of base station apparatus provided with the antenna system which concerns on one Embodiment. It is a block diagram showing composition of a transmitting part which an antenna system concerning a 1st embodiment has. It is a block diagram showing composition of a receiving part which an antenna system concerning a 1st embodiment has. It is a figure which shows a part of base station apparatus provided with the antenna system which concerns on 2nd Embodiment. It is a block diagram showing composition of an antenna system concerning a 2nd embodiment. It is a block diagram showing composition of an antenna module. (A) is a graph showing an evaluation result and is a graph showing a gain when the tilt angle is set to 12 degrees, (b) is a graph showing an evaluation result and the tilt angle is 31 It is a graph which shows the gain at the time of setting so that it may become. FIG. 5 illustrates an example of an antenna system configured to control phase for each sub-array.

[Description of the embodiment]

First, the contents of the embodiment will be listed and described.
(1) An antenna system according to an embodiment includes a distributor that divides an analog transmission signal into a plurality, a plurality of first amplifiers that amplify a plurality of the transmission signals distributed by the distributor, and a plurality of the first amplifiers. The plurality of transmissions provided by the plurality of antenna elements for transmitting the plurality of transmission signals amplified by the first amplifier, the distributor, and the plurality of first amplifiers, and distributed by the distributor And a first phase shifter for adjusting the phase of the signal.

According to the antenna system configured as described above, since the first phase shifter is provided at the front stage of the first amplifier, the first phase shifter is supplied with the transmission signal before being amplified by the first amplifier. Be Since the transmission signal before amplification has lower power compared to the transmission signal after being amplified by the first amplifier, the small phase shifter with relatively low processable signal power can be used as the first phase shifter. It becomes possible to use. As a result, it becomes easier to secure the installation space of the phase shifter than the above-mentioned conventional example, and the installation of the phase shifter is restricted, for example, it becomes possible to provide the first phase shifter for each antenna element. Can be suppressed.

(2) In the above antenna system, the first phase shifter is preferably a semiconductor phase shifter, and in this case, for example, a phase shifter that switches lines by a mechanical contact switch or the like. As compared with the case, the first phase shifter can be further miniaturized, and when the phase setting is changed, the response speed before the setting is reflected in the phase of the transmission signal is quickened. Controllability of the transmission signal can be enhanced.

(3) Further, in the above antenna system, it is preferable that a plurality of the first phase shifters are provided corresponding to each of the plurality of transmission signals distributed by the distributor.
In this case, even if the tilt angle is set relatively large, the phases of the transmission signals transmitted from each of the plurality of antenna elements can be adjusted individually, so the ideal phase condition according to the setting of the tilt angle It can be set to be closer to the phase condition. As a result, even when the tilt angle is set relatively large, it is possible to suppress an increase in side lobes and a decrease in gain.

(4) Further, in the above antenna system, the distributor is a signal processing device installed outside the antenna system, and the transmission signal is given from the signal processing device that performs amplification and signal processing of the transmission signal. In the case of being configured to be able to be connected, it may further include a connection terminal for connecting a signal line for exchanging the transmission signal with the signal processing device.
In this case, the power of the analog transmission signal amplified by the signal processing device provided by the signal processing device does not meet the power required for wireless transmission, or the power of the analog transmission signal from the signal processing device is increased. If necessary, an analog transmission signal supplied from the signal processing apparatus through the connection terminal can be complementarily amplified and transmitted by the first amplifier.

(5) In the antenna system, a plurality of second amplifiers for amplifying a plurality of reception signals received by the plurality of antenna elements, and a combiner for combining the plurality of reception signals amplified by the plurality of second amplifiers A second phase shifter provided between the plurality of second amplifiers and the combiner and performing phase adjustment of the plurality of reception signals amplified by the plurality of second amplifiers;
It is preferable to further comprise
In this case, since the second phase shifter for adjusting the phase of the received signal is provided in addition to the first phase shifter for adjusting the phase of the transmitted signal, the phases of the transmitted signal and the received signal are adjusted independently. can do. As a result, each of the phase of the transmission signal and the phase of the reception signal can be appropriately set according to the situation.
Moreover, according to the antenna system comprised as mentioned above, a 2nd phase shifter is provided in the back | latter stage of a 2nd amplifier. For example, if the second phase shifter is provided in front of the second amplifier, the received signal received by the antenna element is given to the second phase shifter before being amplified by the second amplifier. Since the signal is attenuated by the second phase shifter before being amplified by the second amplifier, the noise level generated in the second amplifier relatively rises and degrades the S / N ratio.
In this respect, according to the above antenna system, since the second phase shifter is provided at the subsequent stage of the second amplifier, the received signal can be amplified without wasted attenuation, and deterioration of the S / N ratio can be suppressed. .

(6) Moreover, the antenna system which is one embodiment includes: a plurality of antenna elements for receiving analog reception signals; a plurality of amplifiers for amplifying a plurality of reception signals received by the plurality of antenna elements; A combiner for combining the plurality of received signals amplified by the amplifier of
And a phase shifter provided between the plurality of amplifiers and the combiner and performing phase adjustment of the plurality of reception signals amplified by the plurality of amplifiers.

According to the antenna system configured as described above, the phase shifter is provided downstream of the amplifier.
For example, if a phase shifter is provided in front of the amplifier so that the received signal received by the antenna element is provided to the phase shifter before being amplified by the amplifier, then the received signal is not amplified by the amplifier. Due to the attenuation by the phase shifter, the noise level generated in the amplifier will rise relatively and degrade the S / N ratio.
In this respect, according to the above antenna system, since the phase shifter is provided at the subsequent stage of the amplifier, the received signal can be amplified without wasted attenuation, and the deterioration of the S / N ratio can be suppressed.

Details of Embodiment
Hereinafter, preferred embodiments will be described with reference to the drawings.
In addition, at least one part of each embodiment described below may be combined arbitrarily.
[Regarding the Entire Configuration of the Base Station Device]
FIG. 1 is a diagram showing a part of a base station apparatus provided with an antenna system according to an embodiment. In the figure, a base station apparatus 1 is used as a base station apparatus in a wireless communication system for mobile phones to which, for example, LTE (Long Term Evolution) is applied, and a mobile terminal (not shown) such as a mobile phone It has a function of performing wireless communication.
The base station apparatus 1 includes a baseband unit (BBU: Base Band Unit) 2 and an active antenna system 3 as shown in the figure.

The baseband unit 2 is connected to an active antenna system 3 (hereinafter also referred to simply as the antenna system 3) by a signal transmission line (optical transmission line or electrical transmission line) 4 extending from the baseband unit 2.

The baseband unit 2 has a function of performing digital modulation processing on transmission data supplied from an upper network (not shown) and generating a transmission baseband signal (I / Q signal) which is a digital signal.
The baseband unit 2 applies a transmission baseband signal obtained by modulating transmission data to the antenna system 3 via the signal transmission path 4.

Further, the baseband unit 2 obtains a reception baseband signal (I / Q signal) which is a digital signal supplied from the antenna system 3 through the signal transmission line 4 and performs digital demodulation processing on the reception baseband signal. To generate received data.
The baseband unit 2 applies the received data obtained by demodulating the received baseband signal to the upper network.

Thus, the baseband unit 2 has a function of performing processing such as digital modulation / demodulation processing on data and baseband signals transmitted and received by wireless communication.

The antenna system 3 includes a plurality of antenna elements 5 for transmitting and receiving radio frequency signals inside the housing 3a, and when the base station apparatus 1 performs radio communication with a mobile terminal, the radio communication Has a function of transmitting and receiving a radio signal related to

The plurality of antenna elements 5 include a pair of

antenna element groups

5a and 5b. The plurality of antenna elements 5a1 constituting one antenna element group 5a and the plurality of antenna elements 5b1 constituting the other antenna element group 5b are configured to have different polarization directions.
The plurality of antenna elements 5a1 constituting one antenna element group 5a are arranged at predetermined intervals in the vertical direction. The other antenna element group 5b is also arranged at predetermined intervals in the vertical direction. Each of the two

antenna element groups

5a and 5b constitutes an array antenna.

The antenna system 3 can transmit and receive a radio signal related to wireless communication by two signal systems by including a pair of

antenna element groups

5a and 5b each forming an array antenna.

[Configuration of Transmitter of Antenna System]
FIG. 2 is a block diagram showing the configuration of the transmitting unit of the antenna system 3 according to the first embodiment.
The antenna system 3 includes an interface (I / F) 9 to which a signal transmission path 4 extending from the baseband unit 2 is connected, a digital signal processor 10, and a transmitter 8.
The interface unit 9 has a function of performing processing related to signal communication performed with the baseband unit 2 via the signal transmission path 4. When the transmission baseband signal which is a digital signal is given by communication from the baseband unit 2 through the signal transmission path 4, the interface unit 9 gives the given transmission baseband signal to the digital signal processing unit 10.

The digital signal processing unit 10 performs digital signal processing on the transmission baseband signal supplied from the interface unit 9 as necessary, and then supplies the transmission baseband signal to the transmission unit 8. The digital signal processing unit 10 also performs processing of the baseband signal in the receiving unit as described later.

Here, the transmission baseband signal provided from the baseband unit 2 includes a first transmission baseband signal and a second transmission baseband signal. These two transmission baseband signals respectively correspond to the above-mentioned two signal systems. The first transmission baseband signal is given to the signal system corresponding to the antenna element group 5a. The second transmission baseband signal is applied to a signal system corresponding to the antenna element group 5b.

The digital signal processing unit 10 obtains the first transmission baseband signal and the second transmission baseband signal from among the transmission baseband signals supplied from the baseband unit 2, and supplies both signals to the transmission unit 8.

The transmitting unit 8 converts the transmission baseband signal supplied from the baseband unit 2 into a transmission signal of the radio frequency, and distributes the converted transmission signal of the radio frequency to each of the plurality of antenna elements 5.
The transmitting unit 8 has two signal systems of a signal system corresponding to the antenna element group 5a and a signal system corresponding to the antenna element group 5b. Therefore, the digital signal processing unit 10 applies the first transmission baseband signal to the signal system corresponding to the antenna element group 5a, and applies the second transmission baseband signal to the signal system corresponding to the antenna element group 5b.
Since both signal systems have the same configuration, in the following description, only the signal system corresponding to the antenna element group 5a will be described.

The transmission unit 8 includes a digital-to-analog converter (DAC) 11, a processing unit 12, and a distributor 13. The transmission unit 8 is configured to perform signal processing on an analog signal.

The digital-to-analog converter 11 has a function of converting a first transmission baseband signal which is a digital signal supplied from the digital signal processing unit 10 into an analog signal.
The digital-to-analog converter 11 supplies the first transmission baseband signal converted to an analog signal to the processing unit 12 connected to the subsequent stage of the digital-to-analog converter 11.
The processing unit 12 orthogonally modulates the first transmission baseband signal composed of the I signal and the Q signal supplied from the digital-to-analog converter 11, and multiplies the local signal of the radio frequency by the signal after the orthogonal modulation. Convert to a transmission signal which is a signal of
Thus, the processing unit 12 has a function of converting the first transmission baseband signal supplied from the digital-to-analog converter 11 into a transmission signal.

The processing unit 12 applies the transmission signal obtained by processing the first transmission baseband signal to the distributor 13 connected to the subsequent stage of the processing unit 12.
The distributor 13 distributes the transmission signal to a plurality corresponding to each of the plurality of antenna elements 5 (5a1).

The transmitting unit 8 further includes a plurality of first phase shifters 15, a plurality of power amplifiers 16, and a plurality of antenna duplexers 17.
A plurality of first phase shifters 15, power amplifiers 16, and antenna sharing devices 17 are provided corresponding to each of the plurality of antenna elements 5a1. Therefore, the first phase shifter 15, the power amplifier 16, and the antenna sharing device 17 are provided between the splitter 13 and each antenna element 5a1.

A plurality of first phase shifters 15 are connected to the subsequent stage of the distributor 13. The transmission signal distributed by the distributor 13 is given to each first phase shifter 15.
Each first phase shifter 15 performs phase adjustment on the transmission signal distributed by the distributor 13. The first phase shifter 15 is configured to be able to externally control the setting regarding the phase adjustment. For example, a control command for controlling the plurality of first phase shifters 15 is given to the antenna system 3 through the signal transmission line 4, and the digital signal processing unit 10 of the antenna system 3 One phase shifter 15 can be configured to be controlled.

A power amplifier 16 is connected to the subsequent stage of each first phase shifter 15. The transmission signal phase-adjusted by each first phase shifter 15 is provided to each power amplifier 16.
Each power amplifier 16 amplifies the transmission signal output from the divider 13 and phase-adjusted by the first phase shifter 15.

An antenna duplexer 17 is connected to the subsequent stage of each power amplifier 16.
The antenna sharing device 17 is connected to an antenna element 5a1 and a receiving unit described later. The antenna sharing device 17 is configured of, for example, a circulator, a duplexer or the like, and has a function of sharing the antenna element 5a1 between the transmitting unit 8 and a receiving unit described later.
The transmission signal distributed by the distributor 13 is applied to each phase shifter 15 and phase-adjusted, and then applied to each power amplifier 16, amplified by the power amplifier 16, and applied to the antenna duplexer 17. Be

The antenna sharing device 17 has a function of providing a signal provided from the power amplifier 16 to the antenna element 5a1, and providing a reception signal provided from the antenna element 5a1 to a receiving unit described later. Therefore, when the transmission signal amplified from the power amplifier 16 is given, the antenna sharing device 17 applies the transmission signal to the antenna element 5a1.
The transmission signal given from each antenna sharing device 17 to each antenna element 5a1 is radiated from the antenna elements 5a1 into space and transmitted as a radio signal.

The plurality of first phase shifters 15 are connected as described above, and are provided between the distributor 13 and the plurality of power amplifiers 16 and in front of the power amplifiers 16.
The plurality of first phase shifters 15 perform phase adjustment on each of the transmission signals distributed by the distributor 13 to thereby transmit an antenna when the transmission signal is transmitted as a radio signal from each of the plurality of antenna elements 5a1. The tilt angle as the element group 5a can be adjusted.
The tilt angle is an angle with respect to the horizontal direction of the beam formed by the wireless signal transmitted from the antenna element group 5a.

According to the antenna system 3 of the above configuration, since the first phase shifter 15 is provided at the front stage of the power amplifier 16, the transmission signal before being amplified by the power amplifier 16 is transmitted to the first phase shifter 15. Given. Since the transmission signal before amplification is lower in power as compared to the transmission signal after being amplified by the power amplifier 16, the small phase shifter having relatively low processable signal power can be used as the first phase shifter 15 It can be used as As a result, securing of the installation space of the first phase shifter 15 is facilitated, and as in the present embodiment, it is possible to provide the first phase shifter 15 for each antenna element 5 a 1. It can suppress that the installation of the phase shifter 15 is restricted.

Further, as described above, since it is possible to use a small phase shifter having relatively low processable signal power as the first phase shifter 15, the first phase shift can be achieved by the semiconductor phase shifter. The vessel 15 can be configured.
In this case, for example, the first phase shifter 15 can be further miniaturized as compared to the case where a phase shifter for switching the line by a mechanical contact switch or the like is used, and the setting of the phase is changed. The response speed until the setting is reflected in the phase of the transmission signal becomes faster. This can improve the controllability of the transmission signal.

As the phase shifter using the above semiconductor, a phase shifter configured to switch the line by a semiconductor switch, a reflection type phase shifter using a 90 degree hybrid coupler and a varactor diode, a vector modulator, etc. are adopted. can do.

Further, in the present embodiment, since the plurality of first phase shifters 15 are provided corresponding to each of the plurality of transmission signals distributed by the distributor 13, even if the tilt angle is set relatively large, a plurality of first phase shifters 15 are provided. The phase of the transmission signal transmitted from each of the antenna elements 5a1 can be adjusted individually, and the phase condition can be set to be closer to the ideal phase condition according to the setting of the tilt angle. As a result, even when the tilt angle is set relatively large, it is possible to suppress an increase in side lobes and a decrease in gain.

[Configuration of Receiver of Antenna System]
FIG. 3 is a block diagram showing the configuration of the receiving unit of the antenna system 3 according to the first embodiment. The receiving unit also has two signal systems of a signal system corresponding to the antenna element group 5a and a signal system corresponding to the antenna element group 5b. Since these two signal systems have the same configuration, also in FIG. 3, only the signal system corresponding to the antenna element group 5 a will be described.

In the figure, the receiving unit 20 of the antenna system 3 converts a reception signal received by each of the plurality of antenna elements 5a1 into a baseband signal, and supplies the baseband signal to the baseband unit 2.

As shown in FIG. 3, the receiving unit 20 includes a plurality of low noise amplifiers 21, a plurality of second phase shifters 22, a combiner 23, a processing unit 24, and an analog-to-digital converter 25 (ADC: Analog to Digital converter), and is configured to perform signal processing on an analog signal.

The low noise amplifier 21 is connected to the antenna duplexer 17 (FIG. 2). Each antenna sharing device 17 provides each low noise amplifier 21 with a received signal of a radio frequency which is an analog signal received by each antenna element 5a1.
The low noise amplifier 21 amplifies the received signal and supplies it to the second phase shifter 22 connected to the subsequent stage of the low noise amplifier 21.
The second phase shifter 22 performs phase adjustment on the reception signal amplified by the low noise amplifier 21. Similar to the first phase shifter 15, the second phase shifter 22 is composed of a phase shifter using a semiconductor.

The second phase shifter 22 is configured to be able to externally control the setting regarding the phase adjustment. For example, a control command for controlling the plurality of second phase shifters 22 is given to the antenna system 3 through the signal transmission line 4, and the digital signal processing unit 10 of the antenna system 3 Control of the two phase shifters 22 can be performed.

A combiner 23 is connected to the subsequent stage of each second phase shifter 22. The received signal phase-adjusted by each second phase shifter 22 is provided to the combiner 23.
The combiner 23 combines the received signals supplied from the second phase shifters 22 and outputs a combined signal (received signal).

The combined signal output from the combining unit 23 is given to the processing unit 24 connected to the subsequent stage of the combining unit 23.
The processing unit 24 multiplies the synthesized signal supplied from the synthesizer 23 by the local signal of the baseband frequency to convert the synthesized signal into a signal of an intermediate frequency, and orthogonally demodulates the signal of the intermediate frequency to obtain a base. Convert to band signal (first reception baseband signal).
Thus, the processing unit 24 has a function of converting the combined signal supplied from the combining unit 23 into a baseband signal.

The processing unit 24 applies the first reception baseband signal obtained by processing the combined signal to the analog-to-digital converter 25 connected to the subsequent stage of the processing unit 24.

The analog-to-digital converter 25 has a function of converting an analog first reception baseband signal supplied from the processing unit 24 into a digital signal.
The analog-to-digital converter 25 applies the first reception baseband signal converted to the digital signal to the digital signal processing unit 10.

In addition to the first reception baseband signal from the signal system corresponding to the antenna element group 5a shown in FIG. 3, the digital signal processing unit 10 receives the second reception from the signal system corresponding to the antenna element group 5b. A baseband signal is also provided.

The digital signal processing unit 10 performs digital signal processing on the first received baseband signal and the second received baseband signal supplied from the analog-to-digital converter 25 as necessary, and then performs the first received baseband signal and the second received baseband signal. 2) The reception baseband signal including the reception baseband signal is supplied to the interface unit 9.
The interface unit 9 applies the reception baseband signal provided from the digital signal processing unit 10 to the baseband unit 2 by communication via the signal transmission path 4.

The plurality of second phase shifters 22 are connected as described above, and are provided between the plurality of low noise amplifiers 21 and the combiner 23. That is, the second phase shifter 22 is provided downstream of the low noise amplifier 21.
The plurality of second phase shifters 22 perform phase adjustment of the plurality of reception signals amplified by the plurality of low noise amplifiers 21. As a result, the plurality of second phase shifters 22 can adjust the tilt angles as the antenna element group 5a when the reception signals are received by the plurality of antenna elements 5a1.

As described above, in the present embodiment, in addition to the first phase shifter 15 that adjusts the phase of the transmission signal, which is a transmission signal, the second phase shifter 22 that adjusts the phase of the reception signal is provided. The phases of the signal and the received signal can be adjusted independently. As a result, each of the phase of the transmission signal and the phase of the reception signal can be appropriately set according to the situation.

Further, in the present embodiment, as described above, the second phase shifter 22 is provided in the rear stage of the low noise amplifier 21.
For example, when the second phase shifter 22 is provided at the front stage of the low noise amplifier 21, the received signal received by the antenna element 5 is given to the second phase shifter 22 before being amplified by the low noise amplifier 21. Then, the received signal is attenuated by the second phase shifter 22 before being amplified by the low noise amplifier 21. For this reason, the noise level generated in the low noise amplifier 21 in which the received signal is amplified thereafter is relatively increased, and the S / N ratio is degraded.
In this respect, according to the present embodiment, since the second phase shifter 22 is provided at the subsequent stage of the low noise amplifier 21, the received signal can be amplified without wasted attenuation, and the deterioration of the S / N ratio is suppressed. can do.

In addition, in the transmission part 8, although the 1st phase shifter 15 was provided in the front | former stage of the power amplifier 16 so that the electric power of the transmission signal given to the 1st phase shifter 15 can be suppressed, the antenna element 5 receives. The received signal does not have a large signal power as compared with the transmission signal supplied to the first phase shifter 15 of the transmission unit 8.
Therefore, in the receiving unit 20, prior to suppressing the signal power supplied to the second phase shifter 22, priority is given to suppressing the attenuation of the signal power. By providing it in the latter stage, it is configured to suppress the deterioration of the S / N ratio.

[Other Embodiments]
FIG. 4 is a view showing a part of a base station apparatus provided with an antenna system 3 according to the second embodiment.
The antenna system 3 of the present embodiment is connected to the baseband unit 2 via a remote radio head (RRH) 30, a digital signal processing unit 10, and a digital analog converter 11. The second embodiment differs from the first embodiment in that the processing unit 12, the analog-to-digital converter 25, and the processing unit 24 are not provided.

The antenna system 3 of this embodiment includes a plurality of antenna elements 5 each including a pair of

antenna element groups

5a and 5b constituting an array antenna, as in the first embodiment, and two signal systems Transmit and receive a radio signal related to the wireless communication.

The baseband unit 2 is connected to the remote radio head 30 by a signal transmission line (optical transmission line or electric transmission line) 31.
The baseband unit 2 applies a transmission baseband signal obtained by modulating transmission data provided from the upper network to the remote radio head 30 via the signal transmission path 31.
Further, the baseband unit 2 acquires a reception baseband signal which is a digital signal supplied from the remote radio head 30 through the signal transmission path 31, performs digital demodulation processing on the reception baseband signal, and receives received data. Has a function to generate.
The baseband unit 2 applies the received data obtained by demodulating the received baseband signal to the upper network.

As in the first embodiment, the transmission baseband signal supplied from the baseband unit 2 includes the first transmission baseband signal and the second transmission baseband signal. These two transmission baseband signals respectively correspond to the above-mentioned two signal systems, and the first transmission baseband signal is given to the signal system corresponding to the antenna element group 5a, and the second transmission baseband signal is The signal system corresponding to the antenna element group 5b is provided.

The remote radio head 30 is provided with a pair of coaxial cables 32 extending from the remote radio head 30. The pair of coaxial cables 32 are connected to a pair of RF connectors 33 provided in the housing 3 a of the antenna system 3. One of the pair of coaxial cables 32 and the pair of RF connectors 33 is included in the signal system corresponding to the antenna element group 5a, and the other is included in the signal system corresponding to the antenna element group 5b.

The remote radio head 30 is also provided with a control cable 34 extending from the remote radio head 30. The control cable 34 is connected to a control connector 35 provided in the housing 3a.
The remote radio head 30 is connected to the antenna system 3 via a pair of coaxial cables 32 and a control cable 34.

The remote radio head 30 obtains the first transmission baseband signal and the second transmission baseband signal from the transmission baseband signal which is a digital signal supplied from the baseband unit 2 and obtains both signals at the radio frequency of the analog signal. It has a function of converting into a transmission signal (a transmission signal corresponding to the antenna element group 5a and a transmission signal corresponding to the antenna element group 5b) and further amplifying the converted transmission signal. The remote radio head 30 converts both transmission baseband signals and applies amplified transmission signals to the antenna system 3 via a pair of coaxial cables 32.

Also, the remote radio head 30 receives two radio frequency reception signals (a composite signal obtained by combining the reception signals of the antenna element group 5a and an antenna), which are analog signals supplied from the antenna system 3 via the pair of coaxial cables 32 respectively. It has a function of amplifying a composite signal obtained by combining the reception signals of the element group 5b and converting it into a reception baseband signal which is a digital signal. The remote radio head 30 applies a digital reception baseband signal to the baseband unit 2 via the signal transmission line 7.

That is, in addition to the signal processing function as the digital signal processing unit 10 included in the antenna system 3 shown in the first embodiment, the remote radio head 30 also includes the digital analog converter 11 included in the transmitting unit 8 and the processing unit 12 Have the function of Furthermore, the remote radio head 30 also has a processing unit 24 of the reception unit 20 and a signal processing function as an analog-to-digital converter 25.

That is, the remote radio head 30 is installed outside the antenna system 3 and constitutes a signal processing apparatus for amplifying the transmission / reception signal and processing the signal.

Also, as described later, the antenna system 3 has a function of adjusting the phase and amplitude of the transmission / reception signal transmitted / received by the antenna system 3.
The baseband unit 2 can control the antenna system 3 by providing the antenna system 3 with a control command for controlling the phase adjustment and the amplitude adjustment of the transmission and reception signals via the remote radio head 30.
A control command for controlling the antenna system 3 is given to the remote radio head 30 through the signal transmission path 31 and is further given to the antenna system 3 from the remote radio head 30 through the control cable 34.

FIG. 5 is a block diagram showing the configuration of the antenna system 3 according to the second embodiment.
The antenna system 3 includes a pair of power distribution / combination units 40 connected to a pair of RF connectors 33 and a large number of antenna modules 41 connected to each of the pair of power distribution / combination units 40.

Of the pair of power distribution / combination units 40 and the multiple antenna modules 41, one power distribution / combination unit 40 located on the left side of the drawing and a plurality of antenna modules 41 connected to the one power distribution / combination unit 40 are antenna elements The signal system corresponding to the group 5a is configured, and a plurality of antenna modules 41 connected to the other power distribution / combination unit 40 and the other power distribution / combination unit 40 correspond to the antenna element group 5b. Configured.
Since both signal systems have the same configuration, in the following description, only the signal system corresponding to the antenna element group 5a will be described.

The power distribution / synthesis unit 40 is connected to the RF connector 33. Thus, the transmission signal from the remote radio head 30 is applied to the power distribution / combination unit 40 via the coaxial cable 32 connected to the RF connector 33.

The power distribution and combination unit 40 has a function of distributing the transmission signal supplied from the remote radio head 30 to each of the antenna modules 41 connected to the power distribution and combination unit 40.
Further, the power distribution and synthesis unit 40 has a function of synthesizing the reception signals supplied from the respective antenna modules 41 and outputting the synthesized signal (reception signal) to the remote radio head 30 via the RF connector 33 and the coaxial cable 32. have.

Each antenna module 41 includes an antenna element 5a1, and has a function of transmitting from the antenna element 5a1 the transmission signal supplied from the power distribution / combination unit 40 and providing the power distribution / combination unit 40 with a reception signal received by the antenna element 5a1. have.
Each antenna element 5a1 provided in the plurality of antenna modules 41 connected to one power distribution / combination unit 40 constitutes an antenna element group 5a (FIG. 4).
The plurality of antenna modules 41 connected to the other power distribution / combination unit 40 includes the antenna elements 5b1, and constitutes an antenna element group 5b (FIG. 4).

Further, each antenna module 41 has a function of adjusting the phase and amplitude of the transmission / reception signal transmitted / received by the antenna element 5a1.
The antenna system 3 includes a control interface unit (control I / F) 42 connected to the control connector 35. A control command for controlling the antenna system 3 is given to the control interface unit 42 through the control cable 34 and the control connector 35.

When a control command for controlling the antenna system 3 is given, the control interface unit 42 gives the control command to each corresponding antenna module 41.
The antenna module 41 to which the control command is given adjusts the phase and amplitude of the transmission / reception signal based on the control command. Each antenna module 41 is individually controlled by a control command.
The control interface unit 42 for controlling the antenna system 3, the control connector 35, and the control cable 34 conform to the Antenna Interface Standards Group (AISG) standard.

FIG. 6 is a block diagram showing the configuration of the antenna module 41. As shown in FIG.
The antenna module 41 includes an antenna element 5 a 1, a first duplexer 50 to which the antenna element 5 a 1 is connected, and a second duplexer 51 connected to the power distribution / combination unit 40. Both

duplexers

50 and 51 have a function to share the antenna element 5a1 for transmission and reception of signals.

The antenna module 41 further includes a first variable attenuator 52, a first phase shifter 53, and a power amplifier 54 between the first duplexer 50 and the second duplexer 51.
The second duplexer 51 is supplied with the transmission signal distributed by the power distribution and combining unit 40. The second duplexer 51 applies the transmission signal supplied from the power distribution / combination unit 40 to the first variable attenuator 52 connected to the second duplexer 51.

The first variable attenuator 52 has a function of adjusting the amplitude of a given transmission signal. Further, the first variable attenuator 52 adjusts the amplitude of the transmission signal based on the control command given from the control interface unit 42.
The first variable attenuator 52 supplies the transmission signal whose amplitude has been adjusted to the first phase shifter 53 connected to the subsequent stage of the first variable attenuator 52.

The first phase shifter 53 adjusts the phase of the transmission signal supplied from the first variable attenuator 52. Similar to the first phase shifter 15 of the first embodiment, the first phase shifter 53 is composed of a phase shifter using a semiconductor.
Further, the first phase shifter 53 adjusts the phase of the transmission signal based on the control command given from the control interface unit 42.
The first phase shifter 53 applies the phase-adjusted transmission signal to the power amplifier 54 connected to the subsequent stage of the first phase shifter 53.

Power amplifier 54 amplifies the transmission signal supplied from first phase shifter 53. The power amplifier 54 supplies the amplified transmission signal to the first duplexer 50 connected to the subsequent stage of the power amplifier 54.
The first duplexer 50 applies the transmission signal supplied from the power amplifier 54 to the antenna element 5a1.
Thus, the transmission signal is radiated from the antenna element 5a1 into space and is transmitted as a radio signal.

Here, the first phase shifter 53 of each antenna module 41 is provided as described above, and is provided between the distribution and combining unit 40 and the power amplifier 54 and at the front stage of the power amplifier 54. ing.
The first phase shifter 53 of each antenna module 41 is individually controlled by a control command. Each first phase shifter 53 adjusts the phase of the transmission signal in accordance with a control command given from the baseband unit 2 to transmit the transmission signal as a radio signal from each of the antenna elements 5a1 of each antenna module 41. The tilt angle as the antenna element group 5a can be adjusted.

Also in the antenna system 3 of the present embodiment, since the first phase shifter 53 is provided at the front stage of the power amplifier 54, a small phase shifter can be used as the first phase shifter 53. . In the present embodiment, a phase shifter using a semiconductor as the small phase shifter is used as the first phase shifter 53. As a result, securing of the installation space of the first phase shifter 53 is facilitated.

The antenna module 41 further includes a low noise amplifier 55, a second phase shifter 56, and a second variable attenuator 57 between the first duplexer 50 and the second duplexer 51. There is.
The first duplexer 50 receives the received signal received by the antenna element 5a1. The first duplexer 50 applies the received signal from the antenna element 5a1 to the low noise amplifier 55 connected to the first duplexer 50.

The low noise amplifier 55 amplifies a given received signal. The low noise amplifier 55 provides the amplified received signal to the second phase shifter 56 connected to the subsequent stage of the low noise amplifier 55.
The second phase shifter 56 performs phase adjustment on the received signal supplied from the low noise amplifier 55. Similar to the first phase shifter 53, the second phase shifter 56 is composed of a phase shifter using a semiconductor.
Also, the second phase shifter 56 adjusts the phase of the received signal based on the control command given from the control interface unit 42.
The second phase shifter 56 supplies the phase-adjusted received signal to a second variable attenuator 57 connected to the subsequent stage of the second phase shifter 56.

The second variable attenuator 57 adjusts the phase of the received signal supplied from the second phase shifter 56. Further, the second variable attenuator 57 adjusts the amplitude of the received signal based on the control command given from the control interface unit 42.
The second variable attenuator 57 applies the reception signal whose amplitude has been adjusted to the second duplexer 51 connected to the subsequent stage of the second variable attenuator 57.
The second duplexer 51 supplies the received signal supplied from the second variable attenuator 57 to the power distribution / combination unit 40.
As described above, the power distribution and combining unit 40 provides the remote radio head 30 with a combined signal obtained by combining the received signals supplied from the respective antenna modules 41. The remote radio head 30 amplifies the composite signal supplied from the antenna system 3, converts it to a reception baseband signal which is a digital signal, and supplies the signal to the baseband unit 2.

Here, the second phase shifter 56 of each antenna module 41 is individually controlled by a control command. Each second phase shifter 56 adjusts the phase of the received signal in accordance with a control command given from baseband unit 2. Thereby, each second phase shifter 56 can adjust the tilt angle as the antenna element group 5a when the signal is received by the antenna element group 5a.

As described above, the antenna system 3 of the present embodiment transmits from the antenna element 5 the transmission signal amplified by the remote radio head 30 given from the remote radio head 30 and the reception signal received by the plurality of antenna elements 5. To the remote radio head 30.

The antenna system 3 of the present embodiment includes an RF connector 33 (connection terminal) for connecting a coaxial cable 32 which is a signal line for transmitting and receiving transmission and reception signals with the remote radio head 30 as a signal processing device. The power distribution / synthesis unit 40 is configured to exchange transmission / reception signals with the remote radio head 30.

In this case, the power of the analog transmission signal amplified by the remote radio head 30 supplied from the remote radio head 30 is less than the power required for radio transmission, or the power of the analog transmission signal from the remote radio head 30 The analog transmit signal supplied from the remote radio head 30 through the RF connector 33 can be complementarily amplified and transmitted by the power amplifier 54 when larger power is required.
Also, when the power of the received signal received by the plurality of antenna elements 5 is less than the power required for reception, or when it is necessary to increase the power of the received signal received by the antenna element 5, a low noise amplifier 55 can amplify the received signal.
As described above, according to the antenna system 3 of the present embodiment, the transmission / reception signal transmitted / received by the antenna element 5 can be complementarily amplified.

The antenna system 3 according to the present embodiment includes the RF connector 33 to enable transmission and reception of analog transmission signals, and a control command for controlling the antenna system 3 from the control connector 35 conforming to the AISG standard. It can be accepted.

Here, in the conventional antenna system, a passive antenna including an RF antenna for transmitting and receiving analog radio frequency transmission / reception signals and a control connector conforming to the AISG standard and having an array antenna capable of phase adjustment is provided. Such an antenna system is usually used in connection with a remote radio head.

On the other hand, since the antenna system 3 of this embodiment has the same interface as the conventional antenna system, it is easier than the conventional antenna system configured as a passive antenna without largely changing the interface. Can be replaced by
Furthermore, since the antenna system 3 of this embodiment has an interface similar to that of the conventional antenna system, IOT (inter-operability test) can be facilitated.

Further, only by replacing the antenna system as described above, the antenna system 3 of the present embodiment having good controllability and characteristics of the transmission and reception signals can be used by providing the phase shifters for each of the antenna elements 5. The transmission / reception function of the base station apparatus 1 can be easily enhanced.

In the antenna system 3 according to each of the above-described embodiments, the pair of

antenna element groups

5a and 5b is provided to transmit and receive a wireless signal related to wireless communication by two signal systems. It may be configured by one signal system, or may be configured to transmit and receive radio signals by a larger number of signal systems.

In each of the above-described embodiments, the phase shifter is constituted by a phase shifter using a semiconductor. However, if the phase shifter having a relatively low processable signal power is a small phase shifter, the semiconductor is used. A phase shifter other than the phase shifter (for example, a ferroelectric element, a ferrite element, a phase shifter by MEMS (Micro-Electro-Mechanical Systems) or the like) may be used.

In the second embodiment, in the antenna module 41, the first phase shifter 53 is connected to the rear stage of the first variable attenuator 52, and the second variable attenuator 57 is connected to the rear stage of the second phase shifter 56. However, the first phase shifter 53 may be connected to the front stage of the first variable attenuator 52, and the second variable attenuator 57 may be connected to the front stage of the second phase shifter 56. .

[About the evaluation test]
Next, an evaluation test performed on the gain when the tilt angle is changed in the antenna system 3 of the first embodiment will be described.
As an example, the antenna system of the first embodiment provided with a phase shifter for each antenna element is adopted, and as a comparative example, one phase shifter for each sub array as shown in FIG. Adopted an antenna system equipped with
The configurations other than the phase shifters are set to be as equal as possible in the embodiment and the comparative example.

The gains obtained when the phases of the antenna systems were adjusted to predetermined values by computer simulation were compared for the above-described example and comparative example.
The tilt angles were set to 12 degrees and 31 degrees.

FIG. 7 is a graph showing the evaluation results, where (a) shows the gain when the tilt angle is set to 12 degrees, and (b) shows the gain when the tilt angle is 31 degrees. It is a figure which shows the gain at the time of carrying out. In the figure, the horizontal axis indicates the tilt angle, and the vertical axis indicates the gain.

In FIG. 7A, it can be seen that relatively high values are obtained in both the example and the comparative example when looking at the gain at a tilt angle of 12 degrees.
On the other hand, in FIG. 7B, when looking at the gain at a tilt angle of 31 degrees, a high value is obtained in the example, but in the comparative example, the gains at angles other than 31 degrees are higher. Even if the antenna system is set to have a tilt angle of 31 degrees, it can be seen that the actual wireless signal does not have a tilt angle according to the setting.

From the above results, in the comparative example, the transmission characteristics do not deteriorate when the set tilt angle is small, but when the tilt angle is set to be large, the gain decreases and the transmission characteristics deteriorate. Can be seen.
On the other hand, in the embodiment, even if the tilt angle is set to be relatively large, it can be confirmed that sufficient gain is obtained and deterioration of the transmission characteristic is suppressed.

As described above, from the results of the evaluation test, according to the antenna system of the present embodiment, it can be confirmed that the deterioration of the transmission characteristic is suppressed even if the tilt angle is set in a wide range.

[Others]
It should be understood that the embodiments disclosed herein are illustrative and non-restrictive in every respect. The scope of the present invention is indicated not by the meaning described above but by the claims, and is intended to include the meanings equivalent to the claims and all modifications within the scope.

DESCRIPTION OF SYMBOLS 1 base station apparatus 2 baseband unit 3 active antenna system 3a housing | casing 4 signal transmission path 5 antenna element 5a antenna element group 5b antenna element group 5a1 antenna element 5b1 antenna element 7 signal transmission path 8 transmission part 9 interface part 10 digital signal processing 11 digital-to-analog converter 12 processor 13 divider 15 first phase shifter 16 power amplifier (first amplifier)
17 antenna duplexer 20 receiver 21 low noise amplifier (second amplifier)
22 second phase shifter 23 synthesizer 24 processing unit 25 analog-to-digital converter 30 remote radio head (signal processing device)
31 signal transmission line 32 coaxial cable 33 RF connector (connection terminal)
34 control cable 35 control connector 40 power distribution / synthesis unit 41 antenna module 42 control interface unit 50 first duplexer 51 second duplexer 52 first variable attenuator 53 first phase shifter 54 power amplifier (first amplifier)
55 Low noise amplifier (second amplifier)
56 second phase shifter 57 second variable attenuator

Claims

A distributor for distributing analog transmission signals into a plurality of units;
A plurality of first amplifiers for amplifying the plurality of transmission signals distributed by the distributor;
A plurality of antenna elements for transmitting the plurality of transmission signals amplified by the plurality of first amplifiers;
A first phase shifter provided between the distributor and the plurality of first amplifiers for performing phase adjustment of the plurality of transmission signals distributed by the distributor;
Antenna system equipped with.
The antenna system according to claim 1, wherein the first phase shifter is a semiconductor phase shifter.
The antenna system according to claim 1 or 2, wherein a plurality of the first phase shifters are provided corresponding to each of the plurality of transmission signals distributed by the distributor.
The distributor is a signal processing device installed outside the antenna system and configured to receive the transmission signal from the signal processing device that performs amplification and signal processing of the transmission signal.
The antenna system according to any one of claims 1 to 3, further comprising a connection terminal for connecting a signal line for exchanging the transmission signal with the signal processing apparatus.
A plurality of second amplifiers for amplifying a plurality of reception signals received by the plurality of antenna elements;
A combiner for combining the plurality of received signals amplified by the plurality of second amplifiers;
A second phase shifter provided between the plurality of second amplifiers and the combiner and performing phase adjustment of the plurality of reception signals amplified by the plurality of second amplifiers;
The antenna system according to any one of claims 1 to 4, further comprising:
A plurality of antenna elements for receiving analog received signals;
A plurality of amplifiers for amplifying the plurality of received signals received by the plurality of antenna elements;
A combiner for combining the plurality of received signals amplified by the plurality of amplifiers;
A phase shifter provided between the plurality of amplifiers and the combiner for performing phase adjustment of the plurality of reception signals amplified by the plurality of amplifiers;
Antenna system equipped with.