JP7211853B2 - wireless repeater - Google Patents

Description

The present invention relates to a radio relay apparatus that performs radio communication with both a radio base station and a radio terminal.

With the development of wireless communication technology, construction of a wider communicable area is required. For example, as shown in FIG. 8, a wireless base station 1 that constructs a communication area with a radius of several hundred meters to several kilometers, and a wireless terminal 100 that communicates with the wireless base station 1 in order to eliminate the dead zone of radio waves generated at the wireless base station 1. A radio relay device 10' is installed to construct an extended area with a radius of several tens of meters to several hundred meters.

When expanding the area in which communication is possible using a wireless relay device in this way, in an environment where radio waves from multiple wireless base stations are received by the wireless relay device, wireless terminals in the extended area cannot reach the wireless base station. Radio wave interference is a problem because radio waves of uplink signals are radiated to areas to radio base stations other than those to which the radio terminal is connected. For example, as shown in FIG. 9, when a wireless relay device 10' communicates with a wireless base station 1, it may give unwanted radio wave interference (interfering portion) to another wireless base station 2. FIG.

In order to solve such a problem, in Patent Document 1, a digital signal processor (DSP) monitors the signal level of the interference wave and weights the signal of the received wave so that the signal level of the interference wave is lowered. A radio relay apparatus that updates weight coefficients has been proposed. Further, Japanese Patent Laid-Open No. 2002-200001 proposes a wireless relay device that includes a base unit direction estimation unit that estimates the base unit direction of a wireless base unit. Accordingly, in Patent Document 2, when transmitting communication data from an antenna to a wireless slave device in a place where radio waves from a wireless relay device and radio waves from a wireless master device coexist, the transmission direction of radio waves from the antenna is set to the master device. control in other directions.

JP 2017-17394 JP 2017-108278

However, in the case of a system that requires low delay (for example, the 5th generation mobile communication system), in the case of Patent Document 1, the digital signal processing unit weights the received wave signal, so that the analog signal is converted to the digital signal. There will be delays due to processing of signals, digital signals to analog signals, and digital signal processing. In addition, in the case of Patent Document 2, although it can be expected to eliminate the mixture (interference) of radio waves between the wireless relay device and the wireless slave device (wireless terminal), the wireless master device (wireless base station) and the wireless relay It is difficult to eliminate the interference between the devices due to restrictions between the wireless relay device and the wireless slave device (wireless terminal). For example, if a wireless repeater is installed at the boundary between the areas of two wireless base stations (wireless base stations), estimation becomes difficult if there is no difference in received power. In a path environment, the estimated direction of the wireless base unit (wireless base station) does not necessarily mean that the isolation between the antenna on the wireless base unit (wireless base station) side and the antenna on the wireless slave unit (wireless terminal) side is good. .

The present invention provides a radio relay apparatus that takes into consideration the influence of radio wave interference on a radio base station and the isolation between the antenna on the radio base station side and the antenna on the radio terminal side.
in particular,
a directivity shaping unit for a base station that forms the antenna directivity of an antenna for a base station composed of a plurality of antennas used for communication with one or more wireless base stations;
a terminal-oriented directivity shaping unit that forms the antenna directivity of a terminal-oriented antenna composed of a plurality of antennas used for communication with one or more wireless terminals;
a downlink amplifier that amplifies radio waves received by the antenna for the base station;
an uplink amplifier that amplifies radio waves received by the antenna for the terminal;
a coupling unit for extracting an electrical signal of the radio wave from the downlink amplifier or the uplink amplifier;
converting the electrical signal into a digital signal and performing signal processing to obtain the identification information of the radio base station and the reception power of the electrical signal received from the radio base station corresponding to the identification information; a signal processor that selects at least one radio base station from
a storage unit that stores setting information for setting directivity in the directivity shaping unit, the identification information, and the received power;
a control unit that sets setting information of the at least one radio base station in the directivity shaping unit ;
The signal processing unit is
a base station identification unit that identifies identification information of the one or more wireless base stations from the digital signal;
a received power analysis unit that analyzes the received power of the one or more radio base stations from the electrical signal,
A radio relay apparatus is provided, wherein the signal processing unit selects, as the at least one radio base station, the setting information of the radio base station having the maximum received power .

Here, it is preferable that the signal processing unit selects the setting information so that the pointing direction of the terminal-oriented antenna is opposite to the pointing direction of the base station-oriented antenna.
Further, the signal processing unit may set the antenna directivity of the terminal-oriented antenna by the setting information after setting the antenna directivity of the terminal-oriented antenna by the directivity shaping unit.
Further, it is preferable that the storage section stores the setting information in advance.

According to the present invention, even if there are a plurality of radio base stations, the influence on radio base stations other than the desired radio base station can be reduced by controlling the antenna directivity on the side of the radio base station. It is possible to reduce radio wave interference during communication from the device to the wireless base station.

FIG. 1A is a block diagram showing the functional configuration of a wireless relay device that is one embodiment of the present invention. FIG. 1B is a block diagram showing the downlink amplifier section and the uplink amplifier section of the radio repeater of FIG. 1A separately. FIG. 2A is a block diagram showing the functional configuration of the directivity shaping section of FIG. 1A. FIG. 2B is a block diagram illustrating an example of base station antennas and terminal antennas connected to a directivity shaping unit. FIG. 3A is a diagram showing the arrangement of antenna elements used for base station antennas and terminal antennas. FIG. 3B is a diagram showing the relationship between the number of antenna elements constituting the base station antenna installed in the directivity shaping section of the radio repeater according to one embodiment of the present invention and the normalized directional gain. . FIG. 2 is a schematic diagram showing that a radio relay apparatus, which is an embodiment of the present invention, communicates with a plurality of radio base stations using antennas for base stations; It shows that the directivity shaping unit of the radio repeater according to one embodiment of the present invention has formed a beam (corresponding to "B" in the figure) for the radio base station 1 using the base station antenna. 1 is a schematic diagram; FIG. FIG. 6 is a flow chart showing steps in which the radio relay device 10 sets the directivity with the highest received power corresponding to "B" in FIG. 5 ; FIG. FIG. 7A is a flow chart showing steps for selecting a radio base station having directivity with the highest received power. FIG. 7B is a flow chart showing the steps of selecting a directivity that maximizes the isolation value between the base station antenna and the terminal antenna. 1 is a schematic diagram showing the positional relationship and communication areas between a conventional radio base station and a radio relay device; FIG. FIG. 2 is a schematic diagram showing radio wave interference, which is a problem in a conventional wireless relay device;

With reference to FIG. 1A, a radio relay device 10, which is one embodiment of the present invention, will be described. The radio relay apparatus 10 includes a directivity shaping unit 30 that gives a predetermined directivity to the base station antenna communicating with the radio base station, and a directivity shaping unit 30 that gives a predetermined directivity to the terminal antenna communicating with the wireless terminal. The directivity shaping section 32, the path switching section 40 connected to the directivity shaping section 30, the path switching section 42 connected to the directivity shaping section 32, and the path switching sections 40 and 42 are connected to each other to transmit an electric signal. Downlink amplification unit 50 and uplink amplification unit 52 including coupling units for extraction, signal processing unit 60 connected to downlink amplification unit 50 and uplink amplification unit 52, respectively, and storage unit connected to signal processing unit 60 70, and a control unit 20 connected to the directivity shaping units 30, 32, the path switching units 40, 42, the signal processing unit 60, and the storage unit 70, respectively.

Next, each part of the wireless relay device 10 shown in FIG. 1A will be described. Here, referring to FIG. 2A, the directivity shaping unit 30 of the base station antenna is connected to a phase shifter connected to the path switching unit 40, and connected between the phase shifter and each base station antenna. and an amplitude adjuster. The directivity shaping section 30 changes the phase of power feeding to each base station antenna by means of a phase shifter and the amplitude of power feeding to each base station antenna by means of an amplitude adjuster, according to a signal (indicated by a dashed line) from the control section 20. By changing it, the directivity of the antenna for the base station can be changed (in this regard, the directivity forming section 32 connected to the antenna for each terminal has the same configuration and function). Semiconductors are generally used for the above phase shifters. There is an analog type that changes the phase amount according to the voltage applied to the control terminal of the semiconductor, and an analog type that changes the phase amount depending on the voltage level of multiple control terminals. There is a digital type that changes. Semiconductors are also commonly used for amplitude adjusters, and like the phase shifter, there are analog types that change the amplitude according to the applied voltage, and digital types that change the amplitude depending on the voltage level. , there are variable attenuators that attenuate the amplitude and variable amplifiers that change the gain of the amplifier. In addition to enabling high-speed directivity shaping by using semiconductors for the phase shifter and amplitude adjuster, by placing a patch antenna on the surface of the printed circuit board and the phase shifter and amplitude adjuster on the back side, the size can be reduced. reduction and power supply loss can be suppressed.
Next, FIG. 2B shows an example of a base station antenna connected to the directivity shaping section 30. As shown in FIG. Each base station antenna is connected to a phase shifter and an amplitude adjuster corresponding to the directivity shaped by the directivity shaping section 30 . Such a base station antenna may have one antenna for one system of phase shifter and amplitude adjuster, or may have a plurality of antennas for one system of phase shifter and amplitude adjuster.

Path switching units 40 and 42 are used in the case of a time-division duplex system in which upstream signals and downstream signals are switched at the same frequency. In the case of a frequency division duplex system in which different frequencies are used for uplink signals and downlink signals, for example, as shown in FIG. Instead of units 40, 42, a duplexer may be used to separate upstream and downstream frequencies.

The downlink amplifier section 50 and the uplink amplifier section 52 are configured by analog amplifier circuits. Then, the signal is separated by a combining section (not shown) provided in the downlink amplifier section 50 and the uplink amplifier section 52 and sent to the signal processing section 60 . A directional coupler (coupler) or the like is used as such a coupling unit.

The signal processor 60 converts analog signals received from the downlink amplifier 50 and the uplink amplifier 52 into digital signals, and demodulates the received signals. A base station identification unit of the signal processing unit 60 extracts base station identification information (eg, base station ID) from the demodulated signal. When signals from a plurality of base stations are mixed, a different base station ID corresponding to each base station is obtained. The received power analysis unit of the signal processing unit 60 can analyze the digital signal and obtain the received power value for each base station obtained by the base station identification unit. In this way, the received power of each base station in a given directivity can be obtained.

The storage unit 70 can store the received power of each base station obtained by the signal processing unit 60 . Also, setting information (phase value and amplitude value) for setting in the directivity shaping units 30 and 32 can be saved. Further, by storing such setting information in the storage unit 70 in advance, the directivity shaping units 30 and 32 can be set in a short time, so that the directivity of the antenna for the base station and the antenna for the terminal can be switched with low delay. can be done. When the directivity shaping units 30 and 32 can take time to shape, or when the processing capability of the control unit 20 is high, the information obtained from the signal processing unit 60 is used to set the directivity shaping units 30 and 32. The setting information can also be calculated and obtained on a case-by-case basis.

The control unit 20 receives a signal from the signal processing unit 60 , reads setting information stored in the storage unit 70 , and transmits the setting information to the directivity shaping units 30 and 32 . The control unit 20 also monitors and controls the states of other units.

As described above, according to the wireless relay device 10, since the digital signal processing, which tends to cause delay, is separated from the high-speed analog amplification processing, a low delay can be realized. In addition, since a digital-analog converter is not required compared to a radio repeater that weights received wave signals by digital signal processing, it is possible to reduce size, weight, and cost.

Next, an example of arrangement of a plurality of antenna elements used as antennas for base stations and antennas for terminals will be described with reference to FIG. 3A. FIG. 3A shows an example of a 256-element base station antenna or terminal antenna in which the antenna elements are arranged in a square array (16 rows×16 columns) with a distance of 0.5 wavelength from each other. Note that FIG. 3A shows an example including a plurality of antenna elements arranged in a square array of 256 elements (16 rows×16 columns) as an antenna for a base station or an antenna for a terminal. It may include a plurality of antenna elements arranged in a plane, such as a rectangular array of rows and m columns, a circular array, or a triangular array. Next, in FIG. 3B, the same phase and the same amplitude are given to each antenna element for each base station antenna in which the number of antenna elements shown in FIG. Indicates the directivity when The directivity is normalized at an angle of 0° in the maximum radiation direction. As the number of antenna elements increases, the directivity becomes sharper and the 3 dB beam width (half width) becomes narrower. The half width is 58° for 4 elements, 26° for 16 elements, 13° for 64 elements, and 6.5° for 256 elements. Also, the directional gain of the antenna increases as the number of antenna elements increases. Furthermore, nulls increase as the number of antenna elements increases (the normalized directional gain is minimal). Therefore, for example, the antenna gain difference in the -15° direction is about 30 dB lower with 256 elements than with 4 elements. Further, the more antenna elements, the smaller the half-value width, so the radiation in the unnecessary direction becomes smaller, and the interference can be reduced.

Next, operation of each part of the radio relay apparatus 10 of FIG. 1 will be described with reference to FIGS. 4 and 5. FIG. When the radio relay device 10 communicates with the radio base station 1, the control unit 20 sends signals about the phase amount and amplitude to be set in the phase shifter and the amplitude adjuster that constitute the directivity shaping unit 30 of the antenna for the base station. to output As a result, the control unit 20 can use the antenna for the base station to form beams having directivities corresponding to A to E shown in FIG. The phase and amplitude values for shaping are different). In this way, by outputting a signal about the phase amount and the amplitude from the control unit 20 to the directivity shaping unit 30, the directivity can be changed without physically changing the orientation of the antenna for the base station. (see beam corresponding to "B" in FIG. 5).

Next, with reference to FIG. 6, the steps in which the radio relay device 10 sets the directivity with the highest received power (corresponding to "B" in FIG. 5) will be described. First, in step S500, the number of times k (k is an integer equal to or greater than 1) of setting the directivity of the base station antenna of the radio relay apparatus 10 is set. In step S502, directivity n (n is an integer equal to or greater than 1) is set for the base station antenna. The set count k and the directivity n are stored in the storage unit 70 . Next, in step S504, the signal processing unit 60 of the radio relay apparatus 10 analyzes the received signal from the base station antenna for the directivities 1 to n. Here, the signal processing unit 60 stores, in the storage unit 70, identification information (base station IDs) corresponding to the number of radio base stations and received power for each identification information of the radio base stations. Then, in step S506, the signal processing unit 60 determines whether the directivity n is equal to the set number of times k. If the directivity n is not equal to the set number of times k (if the directivity n has not yet reached the set number of times k), add 1 to n and then return to step S502. On the other hand, if the directivity n is equal to the set number of times k, the process proceeds to step S508, and the signal processing unit 60 selects the reception The setting information (phase value and amplitude value) corresponding to the directivity with the highest power is set in the directivity shaping section 30 .

Next, with reference to FIGS. 7A and 7B, the steps of the wireless relay device 10 setting the directivity with the highest isolation between the base station antenna and the terminal antenna will be described. First, in steps S500 to S510 of FIG. 7A, the identification information of each radio base station and its reception power are examined with respect to the directivity 1 to n of the base station antenna. Note that steps S500 to S506 in FIG. 7A are the same as steps S500 to S506 in FIG. That is, in step S500, the number of times k of setting the directivity of the base station antenna of the radio relay apparatus 10 is set. In step S502, directivity n is set for the base station antenna. The set count k and the directivity n are stored in the storage unit 70 . Next, in step S504, the signal processing unit 60 of the radio relay apparatus 10 analyzes the received signal from the base station antenna for the directivities 1 to n. Here, the signal processing unit 60 stores, in the storage unit 70, identification information (base station IDs) corresponding to the number of radio base stations and received power for each identification information of the radio base stations. Then, in step S506, the signal processing unit 60 determines whether the directivity n is equal to the set number of times k. If the directivity n is not equal to the set number of times k (if the directivity n has not yet reached the set number of times k), add 1 to n and then return to step S502.
On the other hand, if the directivity n is equal to the set number of times k, the process proceeds to step S510, and the signal processing unit 60 selects the reception The identification information (base station ID) of the radio base station with the highest power is stored in the storage unit 70 . Then, the wireless base station with which the wireless relay device 10 communicates is determined.

Next, in steps S512 to S526 in FIG. 7B, the isolation of directivity 0 to m (m is an integer equal to or greater than 1) of the terminal antenna from directivity 0 to n of the base station antenna is examined. First, in step S512, the signal processing unit 60 of the radio relay device 10 sets the number of times i (i is an integer equal to or greater than 1) that the directivity of the terminal antenna is set (this i is stored in the storage unit 70). . In step S514, the signal processing unit 60 inputs 1 to n and 1 to m as initial values. In step S516, the signal processing unit 60 sets the directivity n of the base station antenna. Then, in step S518, the signal processing unit 60 sets the directivity m of the terminal antenna. The set count i and the directivity m are stored in the storage unit 70 . Next, in step S520, the signal processing unit 60 of the radio relay apparatus receives signals from the radio base station (the radio base station having the base station ID stored in the storage unit in S510) with the directivity n of the antenna for the base station. The signal and the received power of the radio wave radiated by the antenna for the terminal with the directivity m are analyzed by the antenna for the base station, and the isolation value Am,n between the antenna for the base station and the antenna for the terminal is stored in the storage unit 70. do. Then, in step S522, the signal processing unit 60 determines whether the directivity m is equal to the set number of times i. If the directivity m is not equal to the set number of times i (if the directivity m has not yet reached the set number of times i), add 1 to m and then return to step S516. On the other hand, if the directivity m is equal to the set number of times i, the signal processing unit 60 proceeds to step S524 and determines whether the directivity n is equal to the set number of times k. If the directivity n is not equal to the set number of times k (if the directivity n has not yet reached the set number of times k), add 1 to n and then return to step S516. On the other hand, if the directivity n is equal to the set number of times k, the process proceeds to step S526, and the signal processing unit 60 selects the maximum isolation value among the isolation values Am,n stored in the storage unit 70 in step S520. The setting information corresponding to the directivity m and the directivity n is selected.

As described in this specification, according to the present invention, radio wave interference is reduced during communication between a wireless base station and a wireless relay device in a wireless relay device, and throughput of communication between the wireless relay device and the base station is increased. It is possible to provide an improved wireless relay device. In addition, it is possible to ensure isolation between the base station-oriented antenna and the terminal-oriented antenna of the radio relay device.
In addition, in order to maintain the disclosure matters of the original application of this application, the descriptions of claims 1 to 9 of the original application of this application are added below.
(Claim 1)
a directivity shaping unit for a base station that shapes the antenna directivity of a base station antenna composed of a plurality of antennas used for communication with one or more wireless base stations;
a terminal-oriented directivity shaping unit that shapes the antenna directivity of a terminal-oriented antenna composed of a plurality of antennas used for communication with one or more wireless terminals;
a downlink amplifier that amplifies radio waves received by the antenna for the base station;
an uplink amplifier that amplifies radio waves received by the antenna for the terminal;
a coupling unit for extracting an electrical signal of the radio wave from the downlink amplifier or the uplink amplifier;
converting the electrical signal into a digital signal and performing signal processing to obtain the identification information of the radio base station and the reception power of the electrical signal received from the radio base station corresponding to the identification information; a signal processor that selects at least one radio base station from
a storage unit that stores setting information for setting directivity in the directivity shaping unit, the identification information, and the received power;
a control unit configured to set the setting information of the at least one radio base station in the directivity shaping unit;
A radio relay device comprising:
(Claim 2)
The signal processing unit is
a base station identification unit that identifies identification information of the one or more wireless base stations from the digital signal;
a received power analysis unit that analyzes the received power of the one or more radio base stations from the electrical signal,
2. The radio relay apparatus according to claim 1, wherein the signal processing unit selects the setting information of the radio base station having the maximum received power as the at least one radio base station.
(Claim 3)
The signal processing unit performs antenna communication between the base station antenna and the terminal antenna.
characterized by selecting the setting information that maximizes the isolation value between channels.
Item 3. The radio relay device according to item 1 or 2.
(Claim 4)
The signal processing unit directs null of the antenna directivity of the terminal-oriented antenna to the directivity direction of the base-station antenna, or directs the antenna directivity of the base-station-oriented antenna to the directivity direction of the terminal-oriented antenna. 4. The wireless relay device according to any one of claims 1 to 3, characterized in that said setting information is selected so that null is directed.
(Claim 5)
4. The signal processing unit according to any one of claims 1 to 3, wherein the setting information is selected such that the pointing direction of the terminal-oriented antenna is directed in a direction opposite to the pointing direction of the base station-oriented antenna. 1. The radio relay device according to claim 1.
(Claim 6)
The signal processing unit, after setting the antenna directivity of the antenna for the terminal by the directivity shaping unit, sets the antenna directivity of the antenna for the base station by the setting information. 6. The radio relay device according to any one of 5.
(Claim 7)
7. The wireless relay device according to claim 1, wherein said storage stores said setting information in advance.
(Claim 8)
The radio relay apparatus according to any one of claims 1 to 7, wherein said base station-oriented antenna or said terminal-oriented antenna has one or more main beams.
(Claim 9)
The radio relay apparatus according to any one of claims 1 to 8, wherein said base station antenna or said terminal antenna has 64 or more antenna elements.

Reference Signs List 1, 2 radio base station 10 radio relay device 20 control section 30, 32 directivity shaping section 40, 42 path switching section 50, 52 line amplification section 60 signal processing section 70 storage section

Claims (4)

a directivity shaping unit for a base station that shapes the antenna directivity of a base station antenna composed of a plurality of antennas used for communication with one or more wireless base stations;
a terminal-oriented directivity shaping unit that shapes the antenna directivity of a terminal-oriented antenna composed of a plurality of antennas used for communication with one or more wireless terminals;
a downlink amplifier that amplifies radio waves received by the antenna for the base station;
an uplink amplifier that amplifies radio waves received by the antenna for the terminal;
a coupling unit for extracting an electrical signal of the radio wave from the downlink amplifier or the uplink amplifier;
converting the electrical signal into a digital signal and performing signal processing to obtain the identification information of the radio base station and the reception power of the electrical signal received from the radio base station corresponding to the identification information; a signal processor that selects at least one radio base station from
a storage unit that stores setting information for setting directivity in the directivity shaping unit, the identification information, and the received power;
a control unit that sets setting information of the at least one radio base station in the directivity shaping unit ;
The signal processing unit is
a base station identification unit that identifies identification information of the one or more wireless base stations from the digital signal;
a received power analysis unit that analyzes the received power of the one or more radio base stations from the electrical signal,
The radio relay apparatus , wherein the signal processing unit selects the setting information of the radio base station having the maximum received power as the at least one radio base station . 2. The radio according to claim 1 , wherein the signal processing unit selects the setting information so that the pointing direction of the terminal-oriented antenna is opposite to the pointing direction of the base station-oriented antenna. Relay device. 2. The signal processing unit, after setting the antenna directivity of the terminal-oriented antenna by the directivity shaping unit , sets the antenna directivity of the base station-oriented antenna with the setting information. 3. The wireless relay device according to 2. The wireless relay device according to any one of claims 1 to 3 , wherein said storage unit stores said setting information in advance.

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