JP6548961B2 - Wireless transmit / receive system, array antenna unit - Google Patents

Description

  The present invention relates to a wireless transmission / reception system and an array antenna unit provided in a base station for wireless communication.

  The array antenna etc. which were shown by patent document 1 etc. are known as prior art. According to the technique of Patent Document 1, “The frequency stabilization signal is distributed and supplied to the phase locked loop of each signal reception unit at a frequency stabilization signal much lower than the RF signal, so the frequency stabilization signal is distributed by the signal line branch. It is possible to eliminate the need for the RF signal splitter used in the known signal receiving apparatus, and it is not necessary to use an RF transmission line for transmission of the frequency stabilization signal. (See specification paragraph 0100 of Patent Document 1).

JP 2000-101464 A

  However, the technique disclosed in Patent Document 1 is a technique on the premise that the frequency of the frequency stabilization oscillator is several MHz to several tens of MHz. Therefore, although not specified in the specification, the frequency of the received signal based on which the technology disclosed in Patent Document 1 is considered to be several hundred MHz to several GHz. However, in the case where the frequency used for communication exceeds 10 GHz, the frequency of the frequency stabilization oscillator also becomes high, so a signal divider for RF is required, and it becomes necessary to use an RF transmission line. That is, when the frequency used for communication exceeds 10 GHz, the technique described in Patent Document 1 can not obtain the effects described in the specification. In addition, when the frequency of the output of the frequency stabilization oscillator is increased, a problem of transmission loss in the RF transmission line also occurs, and therefore the frequency stabilization oscillator should be disposed as close as possible to the array antenna. However, assuming a base station for wireless communication, the array antenna is disposed at the upper part of the steel tower, etc., so the temperature change is large and it is difficult to cope with the case where a signal with high accuracy and stable frequency is required.

  An object of the present invention is to provide a wireless transmission / reception system and an array antenna unit which can arrange an oscillator away from the array antenna unit even when the frequency used for communication is high.

  The wireless transmission and reception system of the present invention has a reference oscillation device, a splitter and a plurality of antenna units. Also, the array antenna unit has a splitter and a plurality of antenna units. The reference oscillator transmits an optical reference signal of a predetermined frequency. The splitter splits the optical reference signal into a plurality of split optical reference signals. One of the distributed light reference signals is input to the antenna unit.

  The first antenna unit of the present invention comprises an O / E converter, a receiving PLO, a transmitting PLO, an antenna element, a receiving quadrature mixer, and a transmitting quadrature mixer. The O / E converter photoelectrically converts the distributed light reference signal into a distributed electrical reference signal. The receive PLO converts the distributed electrical reference signal into a receive reference signal. The transmitting PLO converts the distributed electrical reference signal into a transmitting reference signal. The reception quadrature mixer converts the reception signal from the antenna element into a reception I component analog signal and a reception Q component analog signal using the reception reference signal. The transmit quadrature mixer converts the transmit I component analog signal and the transmit Q component analog signal into a transmit signal using the transmit reference signal and sends it to the antenna element.

  The second antenna unit of the present invention comprises an O / E converter, a shared PLO, an antenna element, a reception quadrature mixer, and a transmission quadrature mixer. The O / E converter photoelectrically converts the distributed light reference signal into a distributed electrical reference signal. The shared PLO converts the distributed electrical reference signal into a reference signal. The receive quadrature mixer converts the received signal from the antenna element into a received I component analog signal and a received Q component analog signal using the reference signal. The transmit quadrature mixer converts the transmit I component analog signal and the transmit Q component analog signal into a transmit signal using the reference signal and sends it to the antenna element.

  According to the wireless transmission / reception system and the array antenna unit of the present invention, since the optical signal (optical reference signal) is used as the reference signal, it is necessary to consider the transmission loss depending on the distance even when the frequency used for communication is high. There is no Therefore, even when the frequency used for communication is high, the oscillator can be placed at a distance from the array antenna unit.

The figure which shows the structural example of the radio | wireless transmission / reception system of this invention. FIG. 2 is a view showing an example of the arrangement of an antenna unit according to the first embodiment. FIG. 7 is a view showing an example of the configuration of an antenna unit of Modification 1; FIG. 7 is a view showing the configuration of an array antenna unit of Modification 2; FIG. 7 is a view showing an example of the configuration of a reference oscillation device of Modification 2;

  Hereinafter, embodiments of the present invention will be described in detail. Note that components having the same function will be assigned the same reference numerals and redundant description will be omitted.

In the first embodiment, it is assumed that the reception and transmission have different frequencies. For example, it is assumed that the frequency is slightly different between reception and transmission as in the FDD (Frequency Division Duplex) method. FIG. 1 shows an example of the configuration of a wireless transmission and reception system according to the present invention. The structural example of the antenna unit of Example 1 is shown in FIG. Radio transceiver system of the present invention, reference oscillator 300 and the splitter 400 and the antenna unit ₁₀₀ 1, ..., has a 100 _N. Further, the array antenna unit 10 is configured by the splitter 400 and the antenna units 100 ₁ ,..., 100 _N. The reference oscillation device 300 and the splitter 400 are connected by an optical fiber 510. As the optical fiber 510, a single optical fiber contained in the optical fiber cable 500 may be used.

  The reference oscillator 300 sends out an optical reference signal of a predetermined frequency. The reference oscillation device 300 may include, for example, a reference oscillator 310, an oscillation side PLO (Phase-Locked Oscillator) 320, an amplifier 330, and an E / O converter 340. The reference oscillator 310 may be selected to satisfy the frequency stability (for example, about ± 0.05 ppm stability) required for the wireless transmission / reception system. For example, a reference oscillator 310 having a temperature compensation function may be used, or a temperature adjustment unit 350 for maintaining the temperature of the reference oscillator 310 in a predetermined range may be disposed in the reference oscillation device 300 as necessary. It is also good. Also, although the array antenna unit 10 is installed at the upper part of the steel tower of the base station or the like, the reference oscillation device 300 may be installed indoors with air conditioning.

  The oscillation side PLO 320 converts the signal of the reference oscillator 310 to a frequency that facilitates E / O conversion and O / E conversion. Specifically, if it is 2 GHz or less, a commonly used laser or photodiode can be used, so the frequency is a frequency at which E / O conversion or O / E conversion is easy. When the frequency used for communication is 10 GHz or more, the oscillation-side PLO 320 may convert the signal from the reference oscillator 310 to 1 GHz to 2 GHz. With such a frequency, another PLO can be used to obtain a stable signal with a frequency of 10 GHz to 80 GHz. The amplifier 330 amplifies the output of the oscillation side PLO 320 and outputs an electrical reference signal. E / O converter 340 converts the electrical reference signal to an optical reference signal. The E / O converter 340 may also include an optical amplifier as necessary.

The splitter 400 splits the optical reference signal into a plurality of split optical reference signals. Specifically, it may be branched into N, which is the number of antenna units. Theoretically, the loss is 3 dB in 2 branches, so it is a loss of 30 dB in 1024 branches. The loss between the reference oscillation device 300 and the antenna unit 100 _n (n is an integer of 1 or more and N or less) is mostly due to the splitter 400, and it is not necessary to consider the transmission loss depending on the distance. Therefore, the intensity of the output of E / O converter 340 may be determined in consideration of the number of branches of splitter 400 (loss due to branching). One of the distributed light reference signals is input to the antenna unit 100 _n .

The antenna unit 100 _{n according to the} first embodiment includes the O / E converter 162, the reception PLO 152, the transmission PLO 252, the antenna element 110, the reception quadrature mixer 120, the transmission quadrature mixer 220, the antenna duplexer 112, the amplifiers 114 and 214. , A / D converters 134 and 136, E / O converters 144 and 146, O / E converters 244 and 246, and D / A converters 234 and 236. The O / E converter 162 photoelectrically converts the distributed light reference signal into a distributed electrical reference signal. As described above, if the frequency of the distributed light reference signal is 2 GHz or less, a general laser or photodiode can be used.

  The receive PLO 152 converts the distributed electrical reference signal (e.g., 1 GHz to 2 GHz) into a receive reference signal (e.g., 10 GHz to 80 GHz). The transmitting PLO 252 converts the distributed electrical reference signal (e.g., 1 GHz to 2 GHz) into a transmitting reference signal (e.g., 10 GHz to 80 GHz). In addition, although the high frequency is shown as an example, this is because patent document 1 shows that an effect is acquired also with the frequency which can not acquire an effect. The present invention can also be used in low frequency bands (several MHz to several tens of MHz of distributed electrical reference signals, and several hundreds of megahertz to several GHz of signals used for communication).

  Reception quadrature mixer 120 includes multipliers 124 and 126 and π / 2 phase shifter 122, and converts the reception signal from the antenna element into a reception I component analog signal and a reception Q component analog signal using a reception reference signal. Convert. The transmission quadrature mixer includes multipliers 224 and 226 and a π / 2 phase shifter 222, and converts the transmission I component analog signal and the transmission Q component analog signal into a transmission signal using a transmission reference signal to obtain an antenna element Send to

The antenna duplexer 112, amplifiers 114 and 214, A / D converters 134 and 136, E / O converters 144 and 146, O / E converters 244 and 246, and D / A converters 234 and 236 It is the same. The antenna duplexer 112 plays the role of sharing one antenna element 110 for transmission and reception. The received I component analog signal is converted to a received I component optical digital signal by the A / D converter 134 and the E / O converter 144. The A / D converter 136 and the E / O converter 146 convert the received Q component analog signal into a received Q component optical digital signal. The O / E converter 244 converts the transmission I component optical digital signal into a transmission I component digital signal which is an electrical signal. The D / A converter 234 converts the transmission I component digital signal into a transmission I component analog signal which is an electrical signal. The O / E converter 246 converts the transmission Q component optical digital signal into a transmission Q component digital signal which is an electrical signal. The D / A converter 236 converts the transmission Q component digital signal into a transmission Q component analog signal which is an electrical signal. In addition, as long as the part of these prior art performs the same function, it may be another structure. Further, the configuration regarding the reception I component optical digital signal, the reception Q component optical digital signal, the transmission I component optical digital signal, and the transmission Q component optical digital signal outside the antenna unit 100 _n does not change the prior art (anything You may use some conventional technology). Therefore, the description is omitted in FIG.

  According to the wireless transmission / reception system and the array antenna unit of the present invention, since the optical signal (optical reference signal) is used as the reference signal, it is necessary to consider the transmission loss depending on the distance even when the frequency used for communication is high. There is no Therefore, even when the frequency used for communication is high, the oscillator (reference oscillator 310) can be placed at a distance from the array antenna unit. And, it is easy to stabilize the frequency of the reference signal. Even when the frequency used for communication is a high frequency such as 10 GHz to 80 GHz, if the frequency of the optical reference signal is set to a predetermined frequency of 1 GHz to 2 GHz, general O / E conversion or E / O conversion Parts can be used.

[Modification 1]
In this modification, it is assumed that the same frequency is used for reception and transmission. For example, in the case of TDD (Time Division Duplex) method. The present modification differs from the first embodiment in that the PLO of the antenna unit 100 _n is shared for reception and transmission. The antenna unit 100 _n will be described as follows by reflecting this difference.

The antenna unit 100 _n includes an O / E converter 162, a shared PLO 153, an antenna element 110, a reception quadrature mixer 120, a transmission quadrature mixer 220, an antenna duplexer 112, amplifiers 114 and 214, and A / D converters 134 and 136. , E / O converters 144, 146, O / E converters 244, 246, and D / A converters 234, 236. The O / E converter 162 photoelectrically converts the distributed light reference signal into a distributed electrical reference signal. The shared PLO 153 converts the distributed electrical reference signal into a reference signal. The reception quadrature mixer 120 converts the reception signal from the antenna element 110 into a reception I component analog signal and a reception Q component analog signal using the reference signal. The transmission quadrature mixer 220 converts the transmission I component analog signal and the transmission Q component analog signal into a transmission signal using the reference signal and sends the transmission signal to the antenna element. With such a configuration, the same effect as that of the first embodiment can be obtained in this modification as well.

  The antenna duplexer 112, the amplifiers 114 and 214, the A / D converters 134 and 136, the E / O converters 144 and 146, the O / E converters 244 and 246, and the D / A converters 234 and 236 are all implemented. As in the example 1, it is a part of the prior art, and may have another configuration as long as it performs the same function.

[Modification 2]
FIG. 4 shows the configuration of the array antenna unit of this modification. The array antenna unit 20 also includes a reference oscillator 360. FIG. 5 is a view showing a configuration example of a reference oscillation device of the modification 2. The reference oscillation device 360 includes a reference signal reproduction unit 361, an oscillation side PLO 320, an amplifier 330, and an E / O converter 340. The antenna unit 100 ₁ outputs the transmission Q component digital signals and transmit I component digital signal, the reference signal reproducing section 361, the frequency is stabilized by using the transmission I component digital signals inputted and transmitted Q component digital signals Play the signal. The oscillation side PLO 320, the amplifier 330, and the E / O converter 340 are the same as in the first embodiment. Although the antenna unit 100 ₁ in FIG. 4 is outputting the transmission Q component digital signals and transmit I component digital signal may be output which antenna units 100 _n.

The configuration of the other array antenna unit 20 is the same as that of the first embodiment and the first modification (the second modification can be applied to both the case of FIG. 2 and the case of FIG. 3). The antenna unit 100 _n is the same as the configuration shown in FIGS. 2 and 3 except that one of the antenna units 100 _n outputs the transmission I component digital signal and the transmission Q component digital signal as described above.

  The transmission I component digital signal and the transmission Q component digital signal are signals obtained by converting the transmission I component optical digital signal and the transmission Q component optical digital signal generated at a location (a location with good environment) away from the array antenna unit 20 into electricity. So the frequency stability is high. That is, also in the case of this modification, the oscillator for the signal to be the reference can be arranged at a position distant from the array antenna unit. Then, the signal reproduced by the reference signal reproduction unit 361 also has high frequency stability.

10, 20 array antenna unit 100 antenna unit 110 antenna element 112 antenna duplexer 114, 214, 330 amplifier 120 quadrature mixer for reception 122, 222 π / 2 phase shifter 124, 126, 224, 226 multiplier 134, 136 A / D converter 144, 146, 340 E / O converter 152 PLO for reception 153 Shared PLO
162, 244, 246 O / E converter 220 Orthogonal mixer for transmission 234, 236 D / A converter 252 PLO for transmission
300, 360 Reference oscillator 310 Reference oscillator 320 Oscillator side PLO 350 Temperature adjuster 361 Reference signal regenerator 400 Splitter 500 Optical fiber cable 510 Optical fiber

Claims (7)

A reference oscillator for transmitting an optical reference signal of a predetermined frequency;
A splitter that splits the optical reference signal into a plurality of distributed optical reference signals;
With multiple antenna units ,
A wireless transmission / reception system having a reference signal reproduction unit , wherein
Each of the antenna units is
Any one of the distributed light reference signals is input;
An O / E converter that photoelectrically converts the distributed light reference signal into a distributed electrical reference signal;
A receiving PLO for converting the distributed electrical reference signal into a receiving reference signal;
A transmitting PLO for converting the distributed electrical reference signal into a transmitting reference signal;
An antenna element,
A reception quadrature mixer for converting a reception signal from the antenna element into a reception I component analog signal and a reception Q component analog signal using the reception reference signal;
A transmitting quadrature mixer that converts a transmitting I component analog signal and a transmitting Q component analog signal into a transmitting signal using the transmitting reference signal and transmits the converted signal to the antenna element;
Equipped with
The reference signal reproduction unit generates the signal of the predetermined frequency using the transmission I component digital signal and the transmission Q component digital signal.
Radio transceiver system comprising a call. A reference oscillator for transmitting an optical reference signal of a predetermined frequency;
A splitter that splits the optical reference signal into a plurality of distributed optical reference signals;
With multiple antenna units ,
A wireless transmission / reception system having a reference signal reproduction unit , wherein
Each of the antenna units is
Any one of the distributed light reference signals is input;
An O / E converter that photoelectrically converts the distributed light reference signal into a distributed electrical reference signal;
A shared PLO that converts the distributed electrical reference signal into a reference signal;
An antenna element,
A reception quadrature mixer for converting a reception signal from the antenna element into a reception I component analog signal and a reception Q component analog signal using the reference signal;
A transmitting quadrature mixer for converting a transmitting I component analog signal and a transmitting Q component analog signal into a transmitting signal using the reference signal and transmitting the converted signal to the antenna element;
Equipped with
The reference signal reproduction unit generates the signal of the predetermined frequency using the transmission I component digital signal and the transmission Q component digital signal.
Radio transceiver system comprising a call. The wireless transmitting and receiving system according to claim 1 or 2,
The radio transmission / reception system, wherein the reference oscillation device includes a reference oscillator and a temperature adjustment unit for maintaining the temperature of the reference oscillator within a predetermined range. A splitter that splits an optical reference signal having a predetermined frequency and input via an optical fiber cable into a plurality of distributed optical reference signals;
With multiple antenna units ,
An array antenna unit having a reference signal reproduction unit ,
Each of the antenna units is
Any one of the distributed light reference signals is input;
An O / E converter that photoelectrically converts the distributed light reference signal into a distributed electrical reference signal;
A receiving PLO for converting the distributed electrical reference signal into a receiving reference signal;
A transmitting PLO for converting the distributed electrical reference signal into a transmitting reference signal;
An antenna element,
A reception quadrature mixer for converting a reception signal from the antenna element into a reception I component analog signal and a reception Q component analog signal using the reception reference signal;
A transmitting quadrature mixer that converts a transmitting I component analog signal and a transmitting Q component analog signal into a transmitting signal using the transmitting reference signal and transmits the converted signal to the antenna element;
Equipped with
The reference signal reproduction unit generates the signal of the predetermined frequency using the transmission I component digital signal and the transmission Q component digital signal.
An array antenna unit characterized by A splitter that splits an optical reference signal having a predetermined frequency and input via an optical fiber cable into a plurality of distributed optical reference signals;
With multiple antenna units ,
An array antenna unit having a reference signal reproduction unit ,
Each of the antenna units is
Any one of the distributed light reference signals is input;
An O / E converter that photoelectrically converts the distributed light reference signal into a distributed electrical reference signal;
A shared PLO that converts the distributed electrical reference signal into a reference signal;
An antenna element,
A reception quadrature mixer for converting a reception signal from the antenna element into a reception I component analog signal and a reception Q component analog signal using the reference signal;
A transmitting quadrature mixer for converting a transmitting I component analog signal and a transmitting Q component analog signal into a transmitting signal using the reference signal and transmitting the converted signal to the antenna element;
Equipped with
The reference signal reproduction unit generates the signal of the predetermined frequency using the transmission I component digital signal and the transmission Q component digital signal.
Array antenna unit, wherein a call. The frequency of the optical reference signal is 1 GHz or more and 2 GHz or less,
The frequency of the said reference signal for reception and the frequency of the reference signal for transmission are 10 GHz or more and 80 GHz or less. The radio | wireless transmission / reception system of Claim 1 or the array antenna unit of Claim 4 characterized by the above-mentioned. The frequency of the optical reference signal is 1 GHz or more and 2 GHz or less,
The frequency of the said reference signal is 10 GHz or more and 80 GHz or less. The radio | wireless transmission / reception system of Claim 2 or the array antenna unit of Claim 5 characterized by the above-mentioned.

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