JP2019009744A - Radio communication device and radio communications system - Google Patents

Abstract

To reduce an influence of a grating lobe.SOLUTION: First and second radio communication devices are characterized in that a plurality of linear microstrip array antennas or quasi-linear microstrip array antennas each constituted by arranging a plurality of linearly-arrayed antenna elements are arranged side by side at predetermined intervals along an orthogonal axis in a direction orthogonal to a linear axis of the microstrip array antennas; a directional beam is formed in the direction of the orthogonal axis by rotating signals, transmitted and received by the plurality of microstrip array antennas, individually to a complex phase; the direction of the orthogonal axis along which the microstrip array antennas are arranged is an orthogonal direction; and planes of polarization of the individual antenna elements are so set that opposite adaptive directional antenna units have identical planes of polarization.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a wireless communication apparatus and a wireless communication system.

  Currently, high-functional mobile communication terminals such as smartphones are explosively spreading. With regard to mobile phones, the third generation mobile communication has shifted to the fourth generation mobile communication, and research and development related to the fifth generation mobile communication (commonly referred to as “5G”) is now underway. One of the studies that have been conducted on 5G is the use of macro cells and small cells. In conventional cellular phones, one service area is set to a radius of several kilometers, and this macro cell area is covered by one base station device. However, there are a very large number of users in such a macro cell. Since the limited system capacity as a whole is shared by each user, when accommodating a huge number of users, the throughput for each individual user is lowered.

  In order to avoid such a decrease in throughput, a technique for setting a small cell, which is a very small service area with a radius of several tens of meters, in a densely populated area where traffic is concentrated has been developed. In this technology, spot traffic is offloaded to a network without using a macro cell by utilizing a small cell. Here, it is assumed that the terminal device can use the communication capability in the small cell and the communication capability in the macro cell simultaneously. By using such a terminal device, user data is accommodated on the small cell side while exchanging information using a macro cell for control information. This makes it possible to make maximum use of the advantages of macro cells and small cells.

  In 5G mentioned above, the target value of transmission speed is set to 10 Gbit / s (gigabit per second) or more, and this small cell can perform efficient traffic offload by performing the same large-capacity communication. There is a need to. In a macro cell, it is assumed that a microwave band with a low frequency is used in order to allow long-distance propagation. However, considering the current state of the microwave band, where frequency resources are already being depleted, small cells that assume relatively short-distance communication are expected to use the quasi-millimeter wave band or the millimeter wave band with a relatively high frequency. Has been. The characteristic of this high frequency band is that propagation attenuation increases in inverse proportion to the square of the frequency, so that the small cell base station is installed at a location relatively close to the user terminal.

  Such a small cell base station is assumed to be installed at a relatively high place such as a building wall surface or a streetlight in a downtown area where many people gather. If a large number of small cell base stations are installed, the user can be efficiently accommodated by dividing into smaller areas, so the off-road effect is high. In these small cell base stations, it is expected to use a millimeter wave band with abundant frequency resources in order to basically increase the capacity. The current focus is on the use of the 28 GHz band, etc., and in order to make up for the shortage of link budget associated with the use of the high frequency band, a large number of antennas are mounted on both the base station device and the terminal station device. A Massive MIMO (Multiple-Input Multiple-Output) configuration is assumed, and high-order spatial multiplexing transmission is expected here. As an example, a square array antenna of a total of 256 elements of 16 elements × 16 elements is mounted on the base station apparatus side, and about 16 elements (for example, a square array of 4 elements × 4 elements) are also mounted on the terminal station apparatus side. It is assumed that

  Here, in these millimeter-wave band systems, since the original link budget is insufficient and a Massive MIMO configuration is assumed, communication in a line-of-sight environment is preferable. However, in the environment where the line-of-sight wave is dominant, the difference between the gain of the first eigenvalue and the gain of the eigenvalue greater than or equal to the second eigenvalue becomes very large as the distribution of eigenvalues of the MIMO channel matrix, and there is an advantage of using the second eigenvalue or greater. There is a tendency to become very small. In other words, in the line-of-sight environment, high-order spatial multiplexing transmission using reflected waves is difficult, and in practice, the maximum is about two multiplexing using polarization (the first eigenmode transmission is performed for each polarization). Any further spatial multiplexing becomes inefficient.

  Therefore, in the case of spatial multiplexing transmission in an environment where the line-of-sight wave is dominant, the first eigenmode or approximate defined for the transmission and reception pairs of the array antennas or individual subarray antennas of the two radio stations. It is effective to assign and transmit one signal sequence for each transmission path corresponding to the first eigenmode, and to perform spatial multiplexing transmission of these in parallel. For example, in Non-Patent Document 1, a plurality of subarrays with a certain degree of separation distance are mounted in a base station apparatus, and a plurality of terminal station apparatuses from these subarrays are connected between terminal station apparatuses with very simple control. This paper introduces multi-user MIMO transmission technology that reduces interference and realizes higher-order spatial multiplexing transmission. In this evaluation, it was assumed that the subarrays mounted on the base station apparatus side are arranged at half-wavelength intervals.

  In addition to this, there is a description related to Non-Patent Document 2, etc., regarding a technique for spatially multiplexing transmission in an environment in which a line-of-sight wave is dominant, in which a radio station apparatus is fixedly installed at a high place unlike an access system. Here, two radio station apparatuses are installed on the roof of the building and on the opposite wall of the building across the road. Specifically, the upper side of the building is a base station device (because it is a base station device that provides an entrance line, henceforth referred to as “wireless entrance base station”), and a relay station is installed on the wall surface of the building. It is assumed that the access small cell base station device is connected to the station. As described above, when the line-of-sight wave is dominant, the transmission line corresponding to the first eigenvalue can transmit very efficiently, but the transmission line after the second eigenvalue caused by the reflected wave has the eigenvalue of the first eigenvalue. Therefore, it is affected by the fact that the link budget was originally insufficient, and it is difficult to secure a gain without securing a gain. Therefore, in the technique described in Non-Patent Document 2, one array antenna is mounted on the relay station device side, while the array antenna is subarrayed on the radio entrance base station side. The first eigenmode transmission is performed between the sub-array of the radio entrance base station and the array antenna of the relay station apparatus.

  Here, in Non-Patent Document 2, by setting the sub-array interval of the radio entrance base station to an optimum condition depending on conditions such as the antenna arrangement of the array antenna of the relay station apparatus, a plurality of signal sequences are spatially multiplexed in a line-of-sight environment. It shows what you can do. When one base station and one relay station communicate on a one-to-one basis, the sub-array interval on the radio entrance base station side is optimized according to the installation environment, so that the correlation between the sub-arrays is the most. This is because the lowering condition can be realized.

  In the technique described in Non-Patent Document 2, when attention is paid to one base station device and one relay station device, the antenna on the base station device side is configured as a subarray, and the interval between the subarrays is increased by separating the subarrays. Correlation is reduced to increase the capacity of a plurality of signal sequences as parallel transmission of the first eigenmode. However, if the relationship between the base station device and the relay station device in this configuration is reversed and each subarray is regarded as an individual relay station device, each relay station device is originally located in a distant positional relationship with each other. The first eigenmode transmission (or transmission corresponding to the approximate solution) for extracting a line-of-sight wave between the relay station apparatus and the base station apparatus has a low correlation with each other, and an environment suitable for spatial multiplexing transmission can be constructed. This is because, in the technology of Non-Patent Document 1 in the above-described access system, the direction in which the terminal station device exists is random as the user moves, whereas the relay station is separated to some extent if it is a fixedly installed relay station. Therefore, it is expected that an angle difference can be secured in the azimuth in which the relay station exists, and as a result, it can be expected that the correlation can be reduced to some extent along with the angle difference. As described in 1, it is possible to realize a low correlation without having to install a plurality of sub-arrays on the base station apparatus side in consideration of optimization of the arrangement of relay stations. In the conventional MIMO transmission technology in these prior arts, the antenna element is characterized in that the characteristic evaluation is performed assuming a square array arranged two-dimensionally in a square lattice, for example, at half-wavelength intervals.

  Here, in the 5th generation mobile communication explained at the beginning, the throughput of 10 Gbit / s or more was targeted, but two first eigenmodes were transmitted in parallel using polarization (two as the spatial multiplexing number). Even in this case, assuming a transmission mode with a frequency utilization efficiency of 5 bits / s / Hz, a bandwidth of 1 GHz is required. Currently, the study is proceeding mainly on the 28 GHz band, etc., but it is difficult to secure a bandwidth of 1 GHz in this frequency band. Assuming that the number of spatial multiplexing is about 2, an operation in which the frequency resource is shifted to a more abundant frequency band is required. As an example, an E band using a 70/80 GHz band is assumed.

  Here, the wavelength in the E band is about 4 millimeters. For example, if a square array is to be constructed at intervals of one wavelength, it is necessary to embed a high power amplifier and / or a low noise amplifier (or both) in each element in a 4 mm × 4 mm square space. However, considering the size of the device, its mounting, and wiring, mounting at this size is not practical. If the size of the device is assumed to be about 1 cm × 1 cm and an isolation distance of about 3 wavelengths including wiring is required, the square array is formed at intervals of 3 wavelengths. However, when the element spacing exceeds ½ wavelength, there is a high correlation direction called a grating lobe in addition to the main lobe.

  For example, as shown in FIG. 11, a linear array antenna with three wavelength intervals (element interval d = 3λ, where λ is a wavelength) is assumed. In FIG. 11, 10-1 to 10-4 are antenna elements, 11-1 to 11-4 are complex phase rotating means such as phase shifters, 12 is a direction of a radio station as a communication partner, and 13 is a direction of a grating lobe. Represents. Assuming that the direction of the wireless station that is the communication partner is the angle θ direction from the front, the path length difference of each element when assuming a plane wave for that direction (in the figure, the wave front having the same phase is indicated by a dotted line) Δ = dSinθ. For this reason, in each element of the antenna elements 10-1 to 10-4, the cumulative value of complex phase rotation of 2π (dSinθ) / λ = 6πSinθ is given for each element using the phase shifters 11-1 to 11-4. Thus, the directivity can be directed in the θ direction indicated by the direction 12 of the wireless station that is the communication partner.

  Specifically, when the antenna element 10-1 is used as a reference, the antenna element 10-2 is short in distance by the path length difference Δ, and thus the complex phase difference is 2π (dSinθ) / λ × 1. In order to cancel this, it is necessary to apply a phase rotation to the antenna element 10-2 by 2π (dSinθ) / λ × 1 rather than the antenna element 10-1. Similarly, the antenna element 10-3 needs to be rotated by 2π (dSinθ) / λ × 1 more than the antenna element 10-2, and the antenna element 10-4 has 2π (2π () than the antenna element 10-3. It is necessary to apply phase rotation by dSinθ) / λ × 1. Therefore, the phase shifter 11-1 has a phase rotation of 2π (dSinθ) / λ × 0 as its accumulated value, and the phase shifter 11-2 has a phase rotation of 2π (dSinθ) / λ × 1 as its accumulated value. The phase shifter 11-3 has a phase rotation of 2π (dSinθ) / λ × 2 as its accumulated value, and the phase shifter 11-4 has a phase rotation of 2π (dSinθ) / λ × 3 as its accumulated value. It is necessary to add to. In addition, in the phase shifters 11-1 to 11-4, the complex phase is usually rotated by being delayed in time by passing through the delay line, but in this case, the complex phase is in the minus direction by the delay line segment. Therefore, the phase is rotated. For example, a complex phase rotation of −π / 2 is equivalent to a complex phase rotation of + 3π / 2 and gives a phase rotation that considers not the absolute value of the phase rotation amount but also the sign. Since the above-described phase rotation is intended to be a positive phase rotation, when using the phase shifters 11-1 to 11-4, care must be taken to adjust the relationship between the signs.

Next, (in Fig. 11, the direction indicated by the arrow 13) direction at an angle theta _g from the front to the following formula (1) is assumed to be satisfied.

Here, in each of the phase shifters 11-1 to 11-4, it is assumed that the phase rotation for canceling the complex phase rotation of 2π (dSinθ) / λ accompanying the path length difference of dSinθ is performed. The effect is taken in. Multiplying both sides to 2 [pi / lambda of the above formula (1), the complex phase rotation amount for each element with respect to the direction of with an angle theta _g on multiplying weights 2πn next, i.e. each antenna element to be synthesized in the same phase Become. For example, when d = 3λ and θ = 0 [deg], highly correlated directions appear as grating lobes in directions of about ± 19 degrees, about ± 42 degrees, and ± 90 degrees. Similarly, when d = 3λ and θ = 30 [deg], highly correlated directions appear as grating lobes in the directions of about ± 56 degrees, about ± 9.6 degrees, and −30 degrees.

  Here, in the case of d <λ / 2, the absolute value of the left side is 1 or less as is apparent from the equation (1). In principle, this equation does not hold and no grating lobe appears. However, when the element spacing is larger than λ / 2, grating lobes appear, and the ratio of the element spacing to the wavelength, that is, the number of grating lobes that appear as the value of d / λ increases, so the effect is It cannot be ignored. This effect is not a problem when communicating with only one radio station on the same frequency channel in an area where interference is not negligible, but spatial multiplexing transmission using the same frequency channel with multiple radio stations. Can be a problem.

  The array antennas assumed in the above non-patent documents are often evaluated in simulations or the like, assuming the condition that the element spacing is about a half wavelength. However, if this is assumed to be used in a high frequency band such as the E band as described above, the physical size of the high power amplifier and the low noise amplifier will be a problem. Mounting extended to several wavelengths is required. For this reason, the grating lobe as described above is generated. In the above description, the case of a linear array having a one-dimensional array has been described as an example. However, in the case of a two-dimensional array antenna having a square lattice shape, for example, the grating lobe depends on the direction of the directional beam to be formed. The direction of occurrence is constantly changing, whether mobile communication targeting the access system or fixed communication assuming an entrance system, and if there is some degree of freedom regarding the arrangement of terminal station devices or relay stations, It cannot be denied that there is a possibility that the correlation between stations becomes high due to the effect of the grating lobe.

Kazuteru Maruta et al., “Multiuser Parallel Transmission with Subarray Time-axis Beamforming in High Frequency Band Massive MIMO”, IEICE Technical Report, vol. 116, no. 11, RCS2016-20, pp. 111-116, April 2016 . Takuto Arai, et al., "Line-of-sight Millimeter-Wave Band Spatial Multiplexing Technology Using Parallel Transmission in the First Eigenmode-Orthogonal Conditions between Eigenbeams", 2015 IEICE Communication Society Conference September 2015

  As described above, the antenna elements mounted on the radio station apparatus are two-dimensionally arranged. However, when a high frequency band such as an E band is assumed, the element interval is set to a half wavelength interval or less. It is difficult. In particular, assuming that an amplifier such as a high-power amplifier or a low-noise amplifier is mounted, and antennas are arranged in accordance with these sizes, the wavelength interval must be several wavelengths. However, when the antenna element interval is greater than or equal to the half wavelength interval, grating lobes begin to appear, and directions with high correlation other than the desired directional beam direction are generated.

  If communication is performed in a point-to-point state where one-to-one wireless stations face each other, the direction in which the grating lobe appears is expected to be different from the communication partner wireless station. However, for example, when one base station apparatus and a plurality of terminal station apparatuses (or a plurality of relay stations) perform spatial multiplexing transmission in a point-to-multipoint state (that is, multi-user MIMO transmission), Since the directional beam grating lobe formed with respect to the radio station can be applied to the directional beam addressed to other radio stations, it can be in a state of mutual interference with high correlation. Even in this case, optimization design may be possible when a small number of radio stations are placed in a limited location, but even if they are fixedly installed, the location where the relay station is installed If the relay stations are to be kept as limited as possible, or if relay stations are arranged freely without optimization design, the relay stations may overlap the grating lobe and deteriorate the characteristics. Cannot be denied.

  Therefore, in a system using a higher frequency band such as the E band, a high-power amplifier and a low-noise amplifier are mounted, but a two-dimensional antenna arrangement is made due to the physical size of these devices. There is a need for an antenna configuration method and a control method thereof that can reduce the effect of grating lobes that occur when the antenna element spacing is increased.

  In view of the above circumstances, an object of the present invention is to provide a technique capable of reducing the influence of grating lobes.

  One embodiment of the present invention is a wireless communication device in a wireless communication system including a first wireless communication device and a second wireless communication device, and the first and second wireless communication devices are one-dimensional. A microstrip array antenna or a quasi-one-dimensional microstrip array antenna formed by arranging a plurality of arrayed antenna elements in a one-dimensional array has an orthogonal axis perpendicular to the one-dimensional axis of the microstrip array antenna. An adaptive type that forms a directional beam in the direction of the orthogonal axis by providing a plurality of complex phase rotations for signals transmitted and received by a plurality of microstrip array antennas arranged side by side at predetermined intervals. A directional antenna unit, wherein the adaptive directional antenna unit is a direct array of the microstrip array antennas. The axial directions are arranged so as to be orthogonal to each other between the first wireless communication device and the second wireless communication device, and the polarization planes are aligned between the adaptive directional antenna units facing each other. The radio communication apparatus is characterized in that the polarization planes of individual antenna elements constituting the microstrip array antenna are set.

  One aspect of the present invention is the above-described wireless communication device, wherein the adaptive directional antenna unit has an interval between projection points when individual antenna elements included in the microstrip array antenna are projected onto the one-dimensional axis. Is set to be equal to or less than a wavelength at a frequency used for communication, and in at least one of the first wireless communication device and the second wireless communication device, an interval in the direction of the orthogonal axis of the microstrip array antenna Is set to be equal to or less than the wavelength at the frequency used for communication.

  One aspect of the present invention is the above-described wireless communication device, wherein the adaptive directional antenna unit has an interval between projection points when individual antenna elements included in the microstrip array antenna are projected onto the one-dimensional axis. Is set to be equal to or less than a wavelength at a frequency used for communication, and at least one of the first wireless communication device and the second wireless communication device with respect to a predetermined angle φ, the adaptive directional antenna When the directional beam formed by the unit is estimated that the radio station apparatus to be interfered with does not exist between the angle −φ and + φ in the direction of the orthogonal axis from the front direction, the microstrip array The distance d in the direction of the orthogonal axis of the antenna is set so as to satisfy the following formula (3) with respect to the wavelength λ at the frequency used for communication.

  One aspect of the present invention is the above-described wireless communication device, wherein the adaptive directional antenna unit is connected to an individual high power amplifier and / or a low noise amplifier corresponding to the microstrip array antenna. The amplifier and / or the low noise amplifier is mounted so that the thickness direction is parallel to the orthogonal direction.

  One embodiment of the present invention is a wireless communication system including one first wireless communication device and a plurality of second wireless communication devices, and the first and second wireless communication devices are one-dimensional. A microstrip array antenna or a quasi-one-dimensional microstrip array antenna formed by arranging a plurality of arrayed antenna elements in a one-dimensional array has an orthogonal axis perpendicular to the one-dimensional axis of the microstrip array antenna. An adaptive type that forms a directional beam in the direction of the orthogonal axis by providing a plurality of complex phase rotations for signals transmitted and received by a plurality of microstrip array antennas arranged side by side at predetermined intervals. A directional antenna unit, the adaptive directional antenna unit having the orthogonal axis on which the microstrip array antennas are arranged. Are arranged such that the directions are orthogonal to each other between the first wireless communication device and the second wireless communication device, and the polarization planes are aligned between the adaptive directional antenna units facing each other. Polarization planes of individual antenna elements constituting the microstrip array antenna are set, and the orthogonal axis of the adaptive directional antenna unit provided in the first wireless communication device is the adaptive type provided in the first wireless communication device. Radio communication characterized by being parallel to the orthogonal axis of the directional antenna unit and fixedly installed so that the orthogonal axis of the adaptive directional antenna unit provided in the second wireless communication device is orthogonal to the horizontal plane System.

  One embodiment of the present invention is a wireless communication system including one first wireless communication device and one or more second wireless communication devices, wherein the first and second wireless communication devices are one-dimensional. A microstrip array antenna or a quasi-one-dimensional microstrip array antenna configured by arranging a plurality of one-dimensionally arranged antenna elements in a direction orthogonal to the one-dimensional axis of the microstrip array antenna A plurality of directional beams are arranged on the axis at predetermined intervals, and a directional beam is formed in the direction of the orthogonal axis by individually applying complex phase rotation to signals transmitted and received by the plurality of microstrip array antennas. An adaptive directional antenna unit is provided, and the adaptive directional antenna unit is arranged before the microstrip array antennas are arranged. The orthogonal axes are arranged such that the directions of the orthogonal axes are orthogonal between the first wireless communication device and the second wireless communication device, and the planes of polarization are aligned between the adaptive directional antenna units facing each other. As described above, the polarization planes of the individual antenna elements constituting the microstrip array antenna are set, and the second radio communication device is fixedly installed on the upper part of the moving body, and the second radio communication device The orthogonal axis of the adaptive directional antenna unit with which the movable body is provided is arranged so as to be orthogonal to the traveling direction of the mobile body, and the first wireless communication device is located at a position overlooking the road on which the mobile body travels from the upper part of the building. The wireless communication system is characterized in that the orthogonal axis of the adaptive directional antenna unit, which is fixedly installed and provided in the first wireless communication device, is disposed so as to be parallel to the road. It is a system.

  According to the present invention, the influence of the grating lobe can be reduced.

It is a figure which shows the outline | summary of the adaptive transmission directional antenna unit of the base station apparatus and terminal station apparatus in the 1st Embodiment of this invention. It is a figure which shows the outline | summary of the adaptive reception directivity antenna unit of the base station apparatus and terminal station apparatus in the 1st Embodiment of this invention. It is a figure which shows the outline | summary of the base station apparatus and terminal station apparatus in the 1st Embodiment of this invention. This is the direction of installation of the adaptive transmission directional antenna unit and the adaptive reception directional antenna unit on the base station device side and the terminal station device side. BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows the outline | summary of the radio | wireless entrance system using the 1st Embodiment of this invention. It is a figure which shows the outline | summary of the mobile access system using the 1st Embodiment of this invention. It is a figure which shows the outline | summary of the adaptive transmission and reception directional antenna unit of the base station apparatus and terminal station apparatus in the 2nd Embodiment of this invention. It is a figure which shows the outline | summary of the adaptive transmission directional antenna unit of the base station apparatus and terminal station apparatus in the 3rd Embodiment of this invention. It is a figure which shows the outline | summary of the adaptive receiving directional antenna unit of the base station apparatus and terminal station apparatus in the 3rd Embodiment of this invention. It is a figure which shows an example of a quasi-one-dimensional microstrip array antenna. It is a figure which shows an example of a linear array antenna.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The essence of the present invention will be described with reference to FIG. 4. First, the overall configuration of the apparatus will be described.

[First Embodiment]
FIG. 1 is a diagram illustrating an outline of an adaptive transmission directional antenna unit of a base station apparatus and a terminal station apparatus according to the first embodiment of the present invention. In FIG. 1, an adaptive transmission directional antenna unit 2 includes one-dimensional microstrip array antennas 20-1 to 20-n (n is an integer of 2 or more), high power amplifiers 21-1 to 21-n, and phase shifters. 22-1 to 22-n, a distributor 23, a mixer 25, and a local oscillator 26.

  The one-dimensional microstrip array antennas 20-1 to 20-n include a plurality of individual antenna elements 24, and are wired so that the path lengths on the wiring for synthesizing the individual antenna elements 24 are the same. While having a strong directivity in the front direction with respect to the horizontal direction, it has a directivity characteristic that has a gentle directivity (or omnidirectionality) with respect to the vertical direction in the drawing. Further, power is supplied to each antenna element 24 constituting the one-dimensional microstrip array antennas 20-1 to 20-n as follows. Power supply from the high power amplifiers 21-1 to 21-n to each antenna element 24 is wired so as to have the same phase and the same amplitude. When the directivity of the one-dimensional microstrip array antennas 20-1 to 20-n is changed in the one-dimensional axis direction, the phase and amplitude are adjusted in advance so that the directivity direction is obtained. Perform power supply wiring.

When one one-dimensional microstrip array antenna 20-1 to 20-n has o individual antenna elements 24 (o is an integer of 2 or more), ₁₀ Log ₁₀ (o) can be obtained by ignoring the passage loss. It is possible to earn a directivity gain of [dB] in addition to the directivity gain of the individual antenna element 24. This directivity gain is fixedly directed in the front direction and cannot be adaptively changed, but the number o of individual antenna elements 24 here and the width at the time of mounting (in the drawing, By changing the width in the horizontal direction, the width of the directional beam can be designed to an arbitrary value. For example, if the 3 dB half-value angle is 10 degrees, the directivity gain changes gently with respect to the angle in the range of ± 5 degrees from the front, and if the angle is exceeded, the gain decreases rapidly.

  An analog baseband signal is input to the adaptive transmission directional antenna unit 2 from the outside, and the input analog baseband signal and the local signal from the local oscillator 26 are multiplied by the mixer 25 to thereby generate a baseband signal. Is converted to a radio frequency signal. Although the description is omitted here, a component outside the band is suppressed by the filter, and the radio frequency signal is input to the distributor 23. In the distributor 23, the input radio frequency signal is branched into n systems, and each of the branched radio frequency signals is input to the phase shifters 22-1 to 22-n. In the phase shifters 22-1 to 22-n, the rotation of the complex phase is given individually and independently. Here, the signal to which a predetermined complex phase rotation is applied is input to the high power amplifiers 21-1 to 21-n, the signal is amplified, and the signals are transmitted from the one-dimensional microstrip array antennas 20-1 to 20-n. The

A large number of these one-dimensional microstrip array antennas 20-1 to 20-n are arranged in the vertical direction (for example, one vertical column in the figure), and these one-dimensional microstrip array antennas 20-1 to 20- are arranged. By adjusting the phase relationship of n by the phase shifters 22-1 to 22-n, it becomes possible to adaptively form directivity having a degree of freedom in the vertical direction with respect to the drawing. By synthesizing n one-dimensional microstrip array antennas 20-1 to 20-n, and ignoring loss or the like, ₁₀ Log ₁₀ (n ) Additional [dB] directivity gain can be earned. In general, the width in the vertical direction of the entire one-dimensional microstrip array antennas 20-1 to 20-n arranged vertically in the drawing is the width in the horizontal direction of the one-dimensional microstrip array antennas 20-1 to 20-n. As a result, it is possible to direct a very sharp directional beam in an adaptively targeted direction with respect to the longitudinal direction of the drawing.

  Although explanation is omitted here, any technique can be applied to the method for calculating the complex phase rotation amount performed by the phase shifters 22-1 to 22-n. For example, as in the technique described in Reference Document 1 below, the calculation of the amount of rotation of the complex phase is performed digitally, and the actual complex phase rotation is analogized using the phase shifters 22-1 to 22-n. It is possible to configure the apparatus with a smaller number of D / A converters. In particular, the technique described in Reference 1 is a technique that can be applied even when the transmission antenna and the reception antenna are physically separated or in the case of an FDD system. In order to avoid a passage loss caused by passing through the TDD switch, a configuration in which a transmission antenna and a high power amplifier as shown in this figure are connected is advantageous.

Further, in order to realize the technique of Reference Document 1, an additional circuit configuration for calculating the complex phase rotation amount is necessary. However, these are not essential in the present invention, and any other conventional ones. Since the circuit configuration of the technology can be substituted, the specific circuit configuration is not clearly shown and described here.
(Reference 1: Atsushi Ota et al., “Digital Assisted Analog Beamforming in Millimeter-Wave Large-Scale Antenna Systems: Proposal of Basic Concepts”, IEICE Technical Report, vol. 116, no. 383, RCS2016-232, pp 135-140, December 2016.)

  FIG. 2 is a diagram illustrating an outline of an adaptive reception directivity antenna unit of the base station apparatus and the terminal station apparatus according to the first embodiment of the present invention. In FIG. 2, the adaptive reception directional antenna unit 3 includes one-dimensional microstrip array antennas 30-1 to 30-n, low noise amplifiers 31-1 to 31-n, phase shifters 32-1 to 32-n, And a local oscillator 36.

  As in FIG. 1, the one-dimensional microstrip array antennas 30-1 to 30-n have a plurality of individual antenna elements 34 mounted thereon, and the path lengths on the wiring for combining the individual antenna elements 34 are the same. Wiring has a directivity characteristic that exhibits a strong directivity in the front direction with respect to the horizontal direction in the drawing, and a gentle directivity (or non-directionality) in the vertical direction in the drawing. Similar to the description in FIG. 1, this directivity gain is fixedly directed in the front direction and cannot be changed adaptively, but here the number o of individual antenna elements 24 and The width of the directional beam can be designed to an arbitrary value by changing the width at the time of mounting (the width in the horizontal direction in the drawing).

  In the adaptive reception directional antenna unit 3, signals received by the one-dimensional microstrip array antennas 30-1 to 30-n are respectively input to the low noise amplifiers 31-1 to 31-n, and weak signals are input to the low noise amplifier 31-. Amplified by 1 to 31-n, and the amplified signal is input to phase shifters 32-1 to 32-n. In the phase shifters 32-1 to 32-n, the rotation of the complex phase is given individually and independently. The signals that have undergone independent complex phase rotation for each antenna element by the phase shifters 32-1 to 32 -n are combined into n signals by the coupler 33, and the combined signals are input to the mixer 35. In the mixer 35, the signal from the coupler 33 is multiplied by the local signal from the local oscillator 36 to convert the radio frequency signal into a baseband signal. The component is suppressed and an analog baseband signal is output.

  Although this is also the same as the description of FIG. 1, the description is omitted here, but any technique is applied as a method for calculating the complex phase rotation amount performed by the phase shifters 32-1 to 32-n. It is also possible. In order to realize the technique of this reference 1, an additional circuit configuration for calculating the complex phase rotation amount is required. However, these are not essential in the present invention, and other arbitrary conventional techniques are used. Since the circuit configuration can be substituted, a specific circuit configuration is not explicitly described and described here.

  FIG. 3 is a diagram illustrating an outline of the base station apparatus and the terminal station apparatus according to the first embodiment of the present invention. In FIG. 3, the base station apparatus and the terminal station apparatus include an adaptive transmission directional antenna unit 2, an adaptive reception directional antenna unit 3, and a baseband unit 90. The baseband unit 90 includes a communication control circuit 91, an interface circuit 92, a MAC layer processing circuit 93, and a baseband signal processing circuit 94. 3 shows a configuration in which the adaptive transmission directional antenna unit 2 and the adaptive reception directional antenna unit 3 are connected to the baseband unit 90 one by one, but a plurality of adaptive transmission directional antennas are shown. It is also possible to perform spatial multiplexing transmission by connecting the unit 2 and a plurality of adaptive reception directional antenna units 3 to the baseband unit 90.

  This spatial multiplexing transmission may be a point-to-point type single user MIMO or a point-to-multipoint type multi-user MIMO. Although variations to the configuration will be described later, it is possible to adopt a configuration in which the adaptive transmission directional antenna unit 2 and the adaptive reception directional antenna unit 3 are integrated, or one adaptive transmission directional antenna unit 2, A configuration in which a plurality of directional beams are formed by the adaptive reception directional antenna unit 3 is also possible.

  Hereinafter, the signal flow will be described. The baseband unit 90 is connected to the network. When the terminal station apparatus here is a relay station, it means a wireless device such as a small cell base station different from the network. In the case of a general terminal station device, the network means a wireless function part in a device such as a smartphone instead of the so-called network itself, or other signal processing function for Internet access. May be. The signal processing functions for these small cell base stations and Internet access have input / output functions for signals to be communicated, and these signals are input / output to / from the interface circuit 92 (I / F circuit in FIG. 3). Is done. In the case of a base station device, it is literally connected to a network.

  When a signal is input from the network, the interface circuit 92 once terminates the signal, and when a signal to be transmitted through a wireless line or control information for controlling the base station apparatus or terminal station apparatus is input from the outside. Recognizes and takes out the control information, inputs control information to the communication control circuit 91, and inputs a signal to be transmitted through the wireless line to the MAC layer processing circuit 93. The MAC layer processing circuit 93 converts the input signal into a wireless format signal to be transmitted / received via a wireless line. Here, overhead for identifying information is added as necessary. This signal is input to the baseband signal processing circuit 94, and the baseband signal processing circuit 94 performs modulation processing as a radio signal. For example, error correction processing or modulation processing of a predetermined transmission method is performed, and preamble signals used for timing detection, channel estimation, frequency error estimation, etc. are added as necessary, and the digital baseband signal is D The analog baseband signals are output after the / A conversion, and are input to the adaptive transmission directional antenna unit 2. The adaptive transmission directional antenna unit 2 converts the baseband signal into a radio frequency signal as described above, and forms and transmits a predetermined directional beam.

  When receiving a signal, the adaptive receiving directional antenna unit 3 forms a predetermined directional beam, receives the signal, converts the signal from a radio frequency signal to a baseband signal, and converts the signal into a baseband signal. The signal is input to the signal processing circuit 94. The baseband signal processing circuit 94 converts the received analog baseband signal into a digital baseband signal by A / D conversion, and performs demodulation processing by predetermined signal processing. For example, the baseband signal processing circuit 94 receives the leading signal of the packetized radio signal, performs timing detection, compensates the frequency error by AFC (Automatic Frequency Control) processing, and performs demodulation processing after channel estimation. The signal sequence transmitted on the transmission side is reproduced. The reproduced signal is input to the MAC layer processing circuit 93, where a predetermined radio signal is terminated, unnecessary overhead is deleted, and the signal is output to the interface circuit 92. The interface circuit 92 reconstructs these signals into a network-side signal format and outputs them.

  The communication control circuit 91 is also connected to the MAC layer processing circuit 93, the baseband signal processing circuit 94, the adaptive transmission directional antenna unit 2, and the adaptive reception directional antenna unit 3, and exchanges information as necessary. Do. For example, the MAC layer processing circuit 93 is instructed to which radio station apparatus the input signal is information related to communication, or the baseband signal processing circuit 94 is supplied with the input signal. It indicates which modulation method is used. When the counterpart radio station of the directional beam formed by the adaptive transmission directional antenna unit 2 and the adaptive reception directional antenna unit 3 changes adaptively, directivity instructions (for example, to the counterpart radio station (for example, The communication control circuit 91 may instruct the phase rotation amount to be given by the phase shifter. Further, the communication control circuit 91 may autonomously generate control information for its own control and communicate with the network side.

  Note that the baseband unit 90, the adaptive transmission directional antenna unit 2, and the adaptive reception directional antenna unit 3 may be configured integrally in a single housing or separated as a configuration connected by a cable. It does not matter if it is installed. For example, in the case of a base station or the like, the adaptive transmission directional antenna unit 2 and the adaptive reception directional antenna unit 3 are slightly higher using a pole-shaped installation tool in order to secure a line of sight with the terminal station apparatus of the communication partner. Although it is assumed that the baseband unit 90 is installed at a position, the baseband unit 90 may be installed at a low place for safety reasons, and a coaxial cable or the like may be connected therebetween.

The above is the overall operation overview of the base station apparatus and terminal station apparatus. Hereinafter, how the adaptive transmission directional antenna unit 2 and the adaptive reception directional antenna unit 3 in actual communication are installed between the base station apparatus and the terminal station apparatus will be described. FIG. 4 is a diagram illustrating an example of installation directions of the adaptive transmission directional antenna unit and the adaptive reception directional antenna unit on the base station device side and the terminal station device side.
FIG. 4A is a diagram illustrating an example of the installation direction on the base station apparatus side, and FIG. 4B is an example of the installation direction on the terminal station apparatus side. For example, on the base station apparatus side shown in FIG. 4A, the one-dimensional microstrip array antennas (20-1 to 20-n or 30-1 to 30-n) are individual antenna elements in one row in the vertical direction of the drawing. (24 or 34) are arranged and arranged in a horizontal alignment. This shows fixed directivity characteristics that are narrowed down to some extent in the vertical direction (vertical and vertical directions in the drawing), while phase rotation of the mounted phase shifter in the horizontal direction (horizontal and horizontal directions in the drawing). It is possible to adaptively form a very sharp directional beam over a wide range by controlling the amount.

  On the other hand, on the terminal station side in FIG. 4B, the one-dimensional microstrip array antennas (20-1 to 20-n or 30-1 to 30-n) are individually arranged in a single row in the horizontal direction of the drawing ( 24 or 34) are arranged and arranged in vertical alignment. This shows fixed directivity characteristics that are narrowed down to some extent in the horizontal direction (horizontal and horizontal directions in the drawing), while phase rotation of the mounted phase shifter in the vertical direction (vertical and vertical directions in the drawing). It is possible to adaptively form a very sharp directional beam over a wide range by controlling the amount.

  As a feature, the directions in which the directional beam formed by the base station apparatus and the relay station apparatus can be waved are substantially orthogonal, one squeezes the directional beam in the horizontal direction and the other squeezes the beam in the vertical direction. Thus, the directivity gain can be ensured only in the pinpoint direction in cooperation with each other. In general, in the case of an array antenna capable of forming a two-dimensional adaptive directivity, the complex phases of antenna elements arranged two-dimensionally on a plane are adjusted independently to be in any direction in the horizontal and vertical directions. On the other hand, a directional beam is formed. However, as explained in the topic, in the case of high frequency band, it is possible to control the amount of independent complex phase rotation while avoiding grating lobes due to physical size restrictions of devices such as high power amplifiers and low noise amplifiers. It has been difficult to construct a two-dimensional array of antennas.

  On the other hand, the one-dimensional microstrip array antenna (20-1 to 20-n or 30-1 to 30-n) shown in FIGS. 1 and 2 has a high power amplifier or a low noise amplifier arranged in each element. Therefore, a one-dimensional antenna array with a uniform path length on the wiring while avoiding grating lobes is set to about a half-wavelength interval (for example, about one wavelength or less, even if not exactly ½). By selecting (Good), the area for high directivity gain is narrowed down. For example, in FIGS. 1 and 2, the directivity gain is low in the horizontal direction of the drawing, and the high directivity gain is shown in the front direction (the elevation angle in the vertical and vertical directions is arbitrary). By arranging a plurality of these (the vertical direction in FIGS. 1 and 2), the directivity in the vertical and vertical directions is adaptively formed. However, this does not narrow down the directivity in the horizontal and horizontal directions in the drawing (the fixed directivity formed by the one-dimensional microstrip array antenna (20-1 to 20-n or 30-1 to 30-n)). Therefore, the radio station apparatus facing the imperfection has directivity characteristics in a direction orthogonal to the imperfection, and these are combined to complement the directivity characteristics.

  In the figure shown in FIG. 4, it is difficult to understand because there is no regulation for polarization, but FIG. 4 (a) and FIG. 4 (b) do not have the same relationship in which the directions are simply orthogonal. For example, FIGS. 4A and 4B show a one-dimensional microstrip array antenna with the plane of polarization rotated 90 degrees so that both are horizontally polarized waves or both are vertically polarized waves in this state. 20-1 to 20-n or 30-1 to 30-n). As a result, for example, a signal transmitted from FIG. 4A with horizontal polarization can be received with the antenna of FIG. 4B as horizontal polarization. An example in which communication is performed while maintaining such a positional relationship on the base station apparatus side and the terminal station apparatus side will be described with reference to FIGS.

  FIG. 5 is a diagram showing an outline of a wireless entrance system using the first embodiment of the present invention. In FIG. 5, 40 is a baseband unit on the base station apparatus side, 41-1 to 41-4 are adaptive transmission / directivity antenna units on the base station apparatus side, and 42-1 to 42-4 are basebands on the relay station side. Units 43-1 to 43-4 are adaptive transmission / reception directional antenna units on the relay station side. The baseband unit 40 on the base station device side and the adaptive transmission / reception directional antenna units 41-1 to 41-4 on the base station device side are connected by a cable. Similarly, each baseband unit 42-1 to 42-4 on the relay station side is connected to each adaptive transmission / reception directional antenna unit 43-1 to 43-4 on the relay station side with a cable.

  The baseband unit 40 on the base station apparatus side and the adaptive transmission / reception directional antenna units 41-1 to 41-4 operate integrally as a base station apparatus. Similarly, the baseband unit 42-k (k is any one of 1 to 4) and the adaptive transmission / reception directional antenna unit 43-k integrally operate as a relay station device. Although not shown here, for example, a small cell base station is connected to each baseband unit 42-1 to 42-4 on the relay station side, and the small cell base station communicates with user terminals in its subordinate areas. Can be done. The baseband unit 40 on the base station device side is connected to the network, and the above-described user terminal can access the Internet via the entrance line between the base station device and the relay station.

  Characteristically, the relay stations are arranged side by side in the horizontal direction, and interference between the relay stations cannot be avoided unless the directional beam on the base station apparatus side forms a sharp directivity in the horizontal direction. For this reason, the adaptive transmission / reception directional antenna units 41-1 to 41-4 on the base station apparatus side are installed in a state of being laid down in the horizontal direction (horizontally long in the horizontal direction) as shown in FIG. Yes. That is, the adaptive transmission / reception directional antenna units 41-1 to 41-4 are installed such that the longitudinal direction is the horizontal direction. On the other hand, the adaptive transmission / reception directional antenna units 43-1 to 43-4 on the relay station side are installed in a vertical state (vertically long state) as shown in FIG. 4B. That is, the adaptive transmission / reception directional antenna units 43-1 to 43-4 are installed such that the longitudinal direction is the vertical direction.

  Thereby, for example, even when spatial multiplexing transmission is performed between one relay station and a base station apparatus using a plurality of adaptive transmission / reception directional antenna units 41-1 to 41-4 on the base station apparatus side, The adaptive transmission / reception directional antenna unit (for example, 43-1) sharpens the directivity in the vertical direction in order to reduce the correlation between the adaptive transmission / reception directional antenna units 41-1 to 41-4. When a signal having a directional beam directed to a transmission / reception directional antenna unit (for example, 41-1) is transmitted, leakage into another adaptive transmission / reception directional antenna unit (for example, 41-4) used for spatial multiplexing is narrowed. On the other hand, when a signal directed to a directional beam is simultaneously transmitted to an adaptive transmission / reception directional antenna unit (for example, 41-4), another adaptive transmission / reception directional antenna unit (for example, By narrowing the leakage to 41-1), it is possible to realize a spatial multiplexing transmission. In this way, the adaptive transmission / reception directional antenna units 43-1 to 43-4 on the relay station side have sharp directivity toward the base station, and signal leakage in different elevation angle directions is limited.

  Similarly, the adaptive transmission / reception directional antenna units (for example, 41-1) on the base station side are arranged in the horizontal direction in order to reduce the correlation between the adaptive transmission / reception directional antenna units 43-1 to 43-4 of different relay stations. When transmitting a signal having a directional beam directed to one adaptive transmission / reception directional antenna unit (for example, 43-1) with sharp directivity, the adaptive transmission / reception directional antenna of another relay station used for spatial multiplexing While suppressing leakage into the unit (eg 43-4), at the same time when a signal directed to the directional beam is sent to the adaptive transmission / reception directional antenna unit (eg 43-4), adaptive transmission / reception of another relay station By suppressing leakage into the directional antenna unit (for example, 43-1), it is possible to realize spatial multiplexing transmission among a plurality of relay stations. In this way, the adaptive transmission / reception directional antenna units 41-1 to 41-4 on the base station side have a sharp directivity in the relay station direction, and signal leakage in different horizontal directions is limited. For this reason, the horizontal angle in the direction in which the reflected wave that is specularly reflected on the wall of the building is incident on the relay station device and the horizontal angle in the direct line-of-sight direction between the relay station device are different. Is possible.

  What is important is that the one-dimensional microstrip array antenna (20-1 to 20-n or 30-1 to 30-n) is arranged at an element interval that does not generate a grating lobe and forms a beam in the front direction. The microstrip array antennas (20-1 to 20-n or 30-1 to 30-n) are also arranged at a narrow element interval of approximately one wavelength or less, thereby forming a one-dimensional microstrip array antenna (20-1 to 20-n or It is possible to suppress the generation of grating lobes even in the direction in which 30-1 to 30-n) are arranged. As shown in FIGS. 1 and 2, devices such as high power amplifiers and low noise amplifiers have physical size restrictions, but compared to the vertical and horizontal directions of vertical x horizontal x height (thickness). Since the height (thickness) direction is relatively narrow, one-dimensional microstrip array antennas (20-1 to 20-n or 30-1 to 30-n) are arranged in multiple stages in this height (thickness) direction, With respect to the spread in the vertical or horizontal direction, there is room for installation by the width of the individual one-dimensional microstrip array antenna (20-1 to 20-n or 30-1 to 30-n). The adaptive transmission / reception directional antenna units 41-1 to 41-4 and 43-1 to 43-4 are configured in combination with the physical shape characteristics of such devices. By complementing the imperfection of the directivity characteristics of one of the base station apparatus or the relay station, the system can realize the desired directivity characteristics by complementarily complementing.

  In addition, when the relay station device exists in a downward direction when viewed from the base station device due to the height difference between the installation locations of the base station device and the relay station device, the adaptive transmit / receive directional antenna unit on the base station device side It is also possible to install with a downward tilt angle so that the beams formed by 41-1 to 41-4 are directed downward in the presence of the relay station apparatus. Similarly, it is installed with an upward tilt angle so that the beams formed by the adaptive transmission / reception directional antenna units 43-1 to 43-4 on the relay station apparatus side are directed upward in the presence of the base station apparatus. Is also possible. In this case, the longitudinal direction of the adaptive transmission / reception directional antenna units 43-1 to 43-4 on the relay station apparatus side may be installed deviating from the vertical direction.

FIG. 6 is a diagram showing an outline of a mobile access system using the first embodiment of the present invention. In FIG. 6, 50 is a baseband unit on the base station apparatus side, 51-1 to 51-2 are adaptive transmission / directivity antenna units on the base station apparatus side, 52 is a baseband unit on the terminal station apparatus side, 53-1 Reference numeral 53-2 denotes an adaptive transmission / reception directional antenna unit on the terminal station apparatus side, and 54 denotes a bus.
On the base station apparatus side, the adaptive transmission / reception directional antenna units 51-1 to 51-2 are connected to the baseband unit 50, and the adaptive transmission / reception directional antenna units 53-1 to 53-2 on the terminal station apparatus side. Are connected to the baseband unit 52. The explanation given in FIG. 5 and the relationship between them are the same.

  In this mode of use, for example, when a large number of users in the bus 54 communicate with each other using a mobile terminal, a wireless LAN (Local Area Network) (for example, Wi-Fi) is used in the bus 54 in order to offload the traffic. -Fi (registered trademark), etc.) are aggregated, and the aggregated traffic is transferred via a wireless line between a terminal station device installed on the ceiling of the bus 54 and a base station installed on the building rooftop, etc. It is also possible. Assuming such a mobile access system, the ceiling portion of the bus 54 can be relatively large. Therefore, if the adaptive transmission / reception directional antenna units 53-1 to 53-2 are installed away from each other, the mutual space is secured. Correlation can be reduced, and spatial multiplexing transmission can be performed. In this case, since the bus 54 always moves in the direction parallel to the road, the adaptive transmission / reception directional antenna units 53-1 to 53-2 on the terminal station apparatus side are moved in the traveling direction as shown in FIG. Therefore, even if the bus 54 moves, the direction orthogonal to the road can always be maintained stably.

  On the other hand, the adaptive transmission / reception directional antenna units 51-1 to 51-2 on the base station apparatus side are installed in the direction parallel to the road as shown in FIG. In FIG. 6, it is set in a state where a downward tilt is provided by protruding from the building in order to secure a road direction view from the building roof. In the case of this arrangement, the adaptive transmission / reception directional antenna units 51-1 to 51-2 can form a sharp directional beam in a wide range with respect to the road direction and have a narrow directivity characteristic in the direction of the road width. Indicates. As a result, even if the bus 54 moves on the road, a directional beam can be formed following it, and the adaptive transmission / reception directional antenna units 53-1 and 53-2 on the terminal station side are separated. With sufficient resolution, the adaptive transmission / reception directional antenna unit 51-1 on the base station apparatus side is replaced with the adaptive transmission / reception directional antenna unit 53-1 on the terminal station apparatus side, and the adaptive transmission / reception directional antenna unit on the base station apparatus side. 51-2 can form directional beams in the adaptive transmission / reception directional antenna unit 53-2 on the terminal station side. As a result, even in an environment where the line-of-sight wave is dominant, it is possible to perform spatial multiplexing transmission in which the first eigen beam or its approximate solution is transmitted in parallel.

  In the above description, the adaptive transmission / reception directional antenna unit is an expression of the adaptive transmission directional antenna unit and the adaptive reception directional antenna unit as a unit. The antenna may be integrated with a horizontal reception directional antenna unit, or may be integrated with a transmission / reception antenna as described later.

  According to the wireless entrance system and the mobile access system in the first embodiment configured as described above, a plurality of one-dimensional microstrip array antennas in which the phase and amplitude of the signal fed to the antenna element are fixed are arranged in parallel. For each one-dimensional microstrip array antenna, high-frequency components (baseband units) such as a high power amplifier and a low nose amplifier are disposed so as to be connected to the back of each one-dimensional microstrip array antenna. . The one-dimensional microstrip array antenna has a large ratio between the vertical and horizontal lengths, and one side is set to be long, but the size of the above-described high-frequency component is also large in the thickness direction and the vertical and horizontal directions, so that these ratios are uniform. By disposing the antenna, the antenna and the high-frequency component can be efficiently mounted. Therefore, the restriction on the element spacing due to the size of the high-frequency components can be relaxed, the array antennas can be arranged at narrow intervals, the grating lobes can be suppressed, and the correlation to the direction other than the desired directivity direction can be achieved. Can be suppressed.

[Second Embodiment]
In the second embodiment, a case where a one-dimensional microstrip array antenna for transmission and reception is shared will be described.
FIG. 7 is a diagram illustrating an outline of an adaptive transmission / reception directional antenna unit of a base station apparatus and a terminal station apparatus according to the second embodiment of the present invention. In FIG. 7, the adaptive transmission / reception directional antenna unit 6 includes high power amplifiers 21-1 to 21-n, phase shifters 22-1 to 22-n, a distributor 23, a mixer 25, and low noise amplifiers 31-1 to 31. -N, phase shifters 32-1 to 32-n, coupler 33, mixer 35, one-dimensional microstrip array antennas 60-1 to 60-n, antenna element 61, TDD switches 62-1 to 62-n, and The local oscillator 66 is provided.

  In the first embodiment (FIGS. 1 and 2), the adaptive transmission directional antenna unit 2 and the adaptive reception directional antenna unit 3 are separated for transmission and reception, but here, a one-dimensional microstrip array antenna is used. 60-1 to 60-n are shared for transmission and reception, and the switching is performed by the TDD switches 62-1 to 62-n. The TDD switches 62-1 to 62-n follow the instructions from the communication control circuit, and when transmitting signals, the high power amplifiers 21-1 to 21-n and the one-dimensional microstrip array antennas 60-1 to 60-n. When the signal is received, the low noise amplifiers 31-1 to 31-n and the one-dimensional microstrip array antennas 60-1 to 60-n are connected.

  In the description of the first embodiment, the transmission antenna and the reception antenna are separated in order to avoid the passage loss of all devices such as the TDD switches 62-1 to 62-n, but if there is a margin in the link budget, the TDD In the case of communication, there is a merit that sharing the transmission / reception antenna is effective use of space. The phase shifters 22-1 to 22-n and 32-1 to 32-n are arranged between the TDD switches 62-1 to 62-n and the one-dimensional microstrip array antennas 60-1 to 60-n. The phase shifters 22-1 to 22-n and 32-1 to 32-n can be shared. Other explanations are the same as those in the first embodiment.

[Third Embodiment]
In the third embodiment, a case where one one-dimensional microstrip array antenna is shared by a plurality of directional beams will be described. Here, K represents the number of directional beams shared.
FIG. 8 is a diagram illustrating an outline of an adaptive transmission directional antenna unit of a base station apparatus and a terminal station apparatus according to the third embodiment of the present invention. In FIG. 8, the adaptive transmission directional antenna unit 7 includes one-dimensional microstrip array antennas 20-1 to 20-n, high power amplifiers 21-1 to 21-n (HPA in FIG. 8), and phase shifter 22. -1-1 to 22-nK (K is an integer of 1 or more), distributors 23-1 to 23-K, antenna element 24, mixers 25-1 to 25-K, local oscillators 26-1 to 26- K and synthesizers 71-1 to 71-n.

  8 differs from FIG. 1 in that in FIG. 8, K directional beams are formed and K signal sequences are spatially multiplexed and transmitted, so that K baseband signals are input. Mixers 25-1 to 25-K for converting signals to radio frequencies are individually mounted, and distributors 23-1 to 23-K and phase shifters 22-1-1-1 to 22-n-1 to 22 are provided. -1-K to 22-n-K are individually prepared for K systems, and each high power amplifier 21-1 to 21-n is processed while performing signal processing on the signals of each system so as to form individual directional beams. The combination is performed by the combiners 71-1 to 71-n. As a result, signals are transmitted by forming K directional beams. Here, since the local oscillators 26-1 to 26-K are local oscillators having the same frequency, it is possible to share them (in this case, the signal of one local oscillator 26 is divided into K systems by a distributor). Branch to the mixer 25-1 to 25-K).

  FIG. 9 is a diagram illustrating an outline of an adaptive reception directivity antenna unit of the base station device and the terminal station device according to the third embodiment of the present invention. In FIG. 9, the adaptive reception directional antenna unit 8 includes one-dimensional microstrip array antennas 30-1 to 30-n, low noise amplifiers 31-1 to 31-n (LNA in FIG. 9), phase shifter 32- 1-1 to 32-n-K, couplers 33-1 to 33 -K, antenna element 34, mixers 35-1 to 35 -K, local oscillators 36-1 to 36 -K, and distributor 81-1. 81-n.

  9 differs from FIG. 2 in that, in FIG. 9, K directional beams are formed to receive K systems of spatially multiplexed signal sequences. The signal is separated and subjected to signal processing for directivity formation by individual phase shifters 32-1-1 to 32-n-1 to 32-1 to K to 32-nK, respectively. Signals of desired directional beams are respectively extracted by 33-1 to 33-K and multiplied by signals from local oscillators 36-1 to 36-K by individual mixers 35-1 to 35-K. As a result, a K-system baseband signal is output. Similarly, in FIG. 9, the local oscillators 36-1 to 36-K are local oscillators having the same frequency, and thus can be shared (in this case, the signal of one local oscillator 36). Are branched into the K system by a distributor and each is input to the mixers 35-1 to 35-K).

  With the above configuration, the adaptive transmission directional antenna unit and the adaptive reception directional antenna unit shown in FIG. 1 and FIG. 2 can support a plurality of directional beams. In FIGS. 8 and 9, in order to avoid complication of the drawing, the three-dimensional device image is not described as in FIGS. 1 and 2, but actually, it is the same as in FIGS. 1 and 2. In addition, by utilizing the fact that the height (thickness) of the device is thinner than the length and width, the device can be mounted without being physically restricted by the device size.

[Fourth Embodiment]
The one-dimensional microstrip array antennas 20-1 to 20-n, 30-1 to 30-n and the like shown in the above-described embodiments are clearly one-dimensional, different from the generally isotropic two-dimensional expansion. In the case of a typical arrangement, for example, for o sufficiently larger than 1, o individual one-dimensional antenna element rows are arranged in two rows (for example, a zigzag arrangement may be arranged by shifting the position). Even if the wiring lengths of the antenna elements are aligned, if the distance between the two rows is sufficiently narrow, it is considered as a quasi-one-dimensional microstrip array antenna (referred to as a quasi-one-dimensional microstrip array antenna for convenience). It is also possible.

For example, referring to Equation (1), if the angle range θ in which the directional beam is to be formed is sufficiently small (for example, within ± 10 degrees), the influence of the first term on the left side of Equation (1) is small. direction theta _g of (those obtained by substituting ± 1 to n of formula (1)) appears first grating lobe is expressed by the following approximate manner.

In other words, for example, even if a grating lobe occurs, if there is no terminal station device or relay station in that direction, and even if reflection waves are taken into account, interference is a problem in that direction. If it is assumed that the range of the direction that should not be between −φ and + φ, it is generally not a problem unless θ _g is included in the range. That is, in this case, the interval d of the (quasi-) one-dimensional microstrip array antenna should satisfy the following condition.

  For example, in the case of φ = 45 degrees, if d is equal to or shorter than (√2) wavelength, Expression (3) is satisfied. For example, consider the quasi-one-dimensional microstrip array antenna shown in FIG. The quasi-one-dimensional microstrip array antenna 63 has a plurality of rows in which individual antenna elements 64 are arranged one-dimensionally (for example, eight one-dimensional antennas arranged horizontally in FIG. 10 are arranged in two rows in the vertical direction). And a total of 16 elements are mounted) and combined on the wiring so that the wiring length of each element becomes equal to form one directional antenna. If the width of the quasi-one-dimensional microstrip array antenna 63 is designed to be (√2) wavelength or less, and these are arranged substantially in the vertical direction in the drawing without any gaps, directivity can be obtained only within ± 10 degrees from the front direction. If formed, directivity can be formed without giving interference to the terminal station apparatus or relay station in the range of ± 45 degrees. In the example of FIG. 10, two rows of one-dimensional antennas are arranged in a nested manner with a 1/2 cycle shift. However, such an arrangement is effective in reducing the element spacing, and is therefore not necessarily square. The quasi-one-dimensional microstrip array antennas may be configured in other arbitrary arrangements without being arranged in a plurality of grid-like rows.

  If the width of the (quasi-) one-dimensional microstrip array antenna can be reduced to one wavelength or less, Equation (3) holds for φ of 0 to 90 degrees, so that the directional beam to be formed is generally in the front direction. In the case of (for example, within ± 10 degrees), it is possible to form individual directional beams so as to have a very low correlation without being aware of the range in which the terminal station device or the relay station exists. Is possible.

[Other supplementary items]
In the above description, each adaptive transmission directional antenna unit or adaptive reception directional antenna unit generates a line-of-sight wave with the adaptive reception directional antenna unit or adaptive transmission directional antenna unit of the opposite radio station apparatus. Communication is performed by forming a directional beam corresponding to the transmission path to be extracted (corresponding to the first eigenmode or an approximate solution thereof), but this directional beam is a beam without mutual null formation. When mutual interference cannot be ignored, precoding or postcoding processing may be separately performed on the transmission side or reception side to achieve higher-precision signal separation.

  In addition, here, the configuration as shown in FIG. 1 and FIG. 2 is shown from the viewpoint of device mounting assuming a high frequency band, but it is not always necessary to perform complex phase rotation processing using a phase shifter, It is also possible to perform phase rotation by digital signal processing (in this case, instead of using a phase shifter, a complex transmission / reception weight is multiplied on the digital baseband signal). Therefore, a feature of the present invention is that an adaptive transmission directional antenna unit, an adaptive reception directional antenna unit obtained by bundling a plurality of stages of one-dimensional microstrip array antennas or quasi-one-dimensional microstrip array antennas, or an adaptive type in which these are integrated. The transmission / reception directional antenna unit is mounted on two opposing radio station devices, and the adaptive directional antenna unit is maintained between the opposing radio stations while maintaining the relationship in which the major axis direction is orthogonal, and the orthogonal positional relationship. It is in the point where it is constructed and installed so that the polarization planes are aligned. Thus, one controls the directivity in the vertical direction and the other controls the directivity in the horizontal direction, and this combination ensures high directivity in the line-of-sight direction of the pinpoint. Further, each (quasi-) one-dimensional microstrip array antenna has a projection point interval projected in the one-dimensional axis direction (a simple element interval in the case of a complete one-dimensional microstrip array antenna) so that it is one wavelength or less. Thus, a grating lobe is not generated in the (quasi) one-dimensional microstrip array antenna alone. Further, a large number of (quasi) one-dimensional microstrip array antennas are arranged at intervals satisfying the equation (3) in a direction orthogonal to the one-dimensional axis to constitute an adaptive directional antenna unit as a whole. In particular, when the directional beam formed by the adaptive directional antenna unit is adaptively distributed over a wide range, the interval between the (quasi-) one-dimensional microstrip array antennas should be one wavelength or less instead of Equation (3). Is preferred. In this way, it is possible to reduce the influence of grating lobes and reduce mutual correlation, thereby enabling wireless transmission with suppressed interference.

In the embodiment of the present invention, the adaptive transmission directional antenna unit 2, the adaptive reception directional antenna unit 3, and the baseband unit 90 have been described as having analog baseband signal input / output. A configuration in which a D / A converter and an A / D converter are mounted in the transmission-type transmission directional antenna unit 2 and the adaptive reception directional antenna unit 3, and a digital baseband signal is input to and output from the baseband unit 90. It does not matter. In this case, a mixer is installed for each individual microstrip array antenna system, and frequency conversion between a baseband signal and a radio frequency is individually performed in each system.
Furthermore, the adaptive transmission directional antenna unit and the adaptive reception directional antenna unit included in the base station device and the terminal device (or relay station) do not necessarily have the same shape, size, and configuration. For example, a microstrip array The physical conditions such as the number of elements constituting the antenna and the aperture length may be different. Similarly, the intervals and the number of stages of the microstrip array antennas configured in multiple stages need not be the same. In general, in communication between opposing radio stations, if the directional beam that constitutes one sufficiently suppresses the grating lobe, the other side may produce a grating lobe in a direction away from the front direction. The effect is expected to be reduced to some extent. Therefore, when the microstrip array antennas are arranged in multi-stages and the axial directions are orthogonal between the opposing radio station apparatuses, in one radio station apparatus, the interval between the microstrip array antennas is one wavelength or more (or formula (3 If the other interval is equal to or less than one wavelength, it is possible to avoid the grating lobe and keep a low correlation with each other by the present invention. .

Furthermore, in the description of “one wavelength or less” in the embodiment of the present invention, when a wireless system having a predetermined bandwidth is assumed, the wavelength means a wavelength corresponding to the center frequency of the band used for communication. Shall.
Furthermore, in this specification, the adaptive transmission / reception directional antenna unit has been described as being configured by a plurality of microstrip antennas. However, instead of the microstrip antenna, individual elements are arranged side by side, and these elements are reduced in loss. If it is possible to connect with the same wiring length while suppressing (for example, branching on the waveguide and connecting to each element), it may be realized by a method other than the microstrip antenna. However, since the method of connecting each element with a microstrip line is currently effective in achieving both low loss and downsizing, the microstrip antenna has been described as a representative example.

  As mentioned above, although embodiment of this invention has been described with reference to drawings, the said embodiment is only the illustration of this invention, and it is clear that this invention is not limited to the said embodiment. is there. Therefore, additions, omissions, substitutions, and other modifications of the components may be made without departing from the technical idea and scope of the present invention.

10-1 to 10-4 ... antenna elements 11-1 to 11-4 ... phase shifters 2, 2-a, 2-b ... adaptive transmission directional antenna units 20-1 to 20-n ... one-dimensional microstrip Array antennas 21-1 to 21-n... High power amplifiers 22-1 to 22-n... Phase shifter 23 ... Divider 24 ... Antenna element 25 ... Mixer 26 ... Local oscillators 3, 3-a, 3-b ... Adaptation Type receiving directivity antenna units 30-1 to 30-n ... one-dimensional microstrip array antennas 31-1 to 31-n ... low noise amplifiers 32-1 to 32-n ... phase shifter 33 ... coupler 34 ... antenna element 35 ... Mixer 36 ... Local oscillator 40 ... Baseband units 41-1 to 41-4 on the base station apparatus side Adaptive transmission / reception directional antenna units 42-1 to 42-4 on the base station apparatus side ... Subband units 43-1 to 43-4 ... Adaptive transmission / reception directivity antenna unit 50 on the relay station side ... Baseband units 51-1 to 51-2 on the base station device side ... Adaptive transmission / reception directivity on the base station device side Antenna unit 52 ... Baseband units 53-1 to 53-2 on the terminal station apparatus side Adaptive transmission / reception directional antenna unit 6 on the terminal station apparatus side ... Adaptive transmission / reception directional antenna units 60-1 to 60-n ... 1 Dimensional microstrip array antenna 61 ... Antenna elements 62-1 to 62-n ... TDD switch 63 ... Quasi-one-dimensional microstrip array antenna 64 ... Antenna element 66 ... Local oscillator 7 ... Adaptive transmission directional antenna units 71-1 to 71- -N: Synthesizer 8 ... Adaptive receiving directional antenna unit 81-1 to 81-n ... Distributor 90 ... Base Command unit 91 ... communication control circuit 92 ... interface circuit 93 ... MAC layer processing circuit 94 ... baseband signal processing circuit

Claims (6)

A wireless communication device in a wireless communication system comprising a first wireless communication device and a second wireless communication device,
The first and second wireless communication devices are:
A one-dimensional microstrip array antenna or a quasi-one-dimensional microstrip array antenna configured by arranging a plurality of one-dimensionally arranged antenna elements in a direction orthogonal to the one-dimensional axis of the microstrip array antenna A plurality of arrayed antennas arranged at predetermined intervals on the orthogonal axis of each of the plurality of microstrip array antennas, and individually transmitting a complex phase to signals transmitted and received by the microstrip array antennas, thereby directing a directional beam in the direction of the orthogonal axis. With an adaptive directional antenna unit to form,
The adaptive directional antenna unit is:
The adaptive directivity is arranged such that the direction of the orthogonal axis in which the microstrip array antennas are arranged is an orthogonal direction between the first wireless communication device and the second wireless communication device. A radio communication apparatus, wherein polarization planes of individual antenna elements constituting the microstrip array antenna are set so that polarization planes are uniform between the conductive antenna units. The adaptive directional antenna unit is:
The distance between the projection points when the individual antenna elements included in the microstrip array antenna are projected onto the one-dimensional axis is set to be equal to or less than the wavelength at the frequency used for communication,
In at least one of the first wireless communication device and the second wireless communication device, the interval in the direction of the orthogonal axis of the microstrip array antenna is set to be equal to or less than a wavelength at a frequency used for communication. The wireless communication device according to claim 1. The adaptive directional antenna unit is:
The distance between the projection points when the individual antenna elements included in the microstrip array antenna are projected onto the one-dimensional axis is set to be equal to or less than the wavelength at the frequency used for communication,
With respect to a predetermined angle φ, in at least one of the first wireless communication device and the second wireless communication device, a directional beam formed by the adaptive directional antenna unit extends from the front direction to the orthogonal axis. When it is estimated that there is no radio station apparatus to be interfered between -φ and + φ in the direction, the interval d in the direction of the orthogonal axis of the microstrip array antenna is the frequency used for communication. The wireless communication apparatus according to claim 1, wherein the wireless communication apparatus is set to satisfy the following formula (1) with respect to the wavelength λ:

The adaptive directional antenna unit is:
An individual high-power amplifier and / or low-noise amplifier is connected corresponding to the microstrip array antenna, and the high-power amplifier and / or low-noise amplifier is mounted so that the thickness direction thereof is parallel to the orthogonal direction. The wireless communication device according to any one of 1 to 3. A wireless communication system comprising one first wireless communication device and a plurality of second wireless communication devices,
The first and second wireless communication devices are:
A one-dimensional microstrip array antenna or a quasi-one-dimensional microstrip array antenna configured by arranging a plurality of one-dimensionally arranged antenna elements in a direction orthogonal to the one-dimensional axis of the microstrip array antenna A plurality of arrayed antennas arranged at predetermined intervals on the orthogonal axis of each of the plurality of microstrip array antennas, and individually transmitting a complex phase to signals transmitted and received by the microstrip array antennas, thereby directing a directional beam in the direction of the orthogonal axis. With an adaptive directional antenna unit to form,
The adaptive directional antenna unit is:
The adaptive directivity is arranged such that the direction of the orthogonal axis in which the microstrip array antennas are arranged is an orthogonal direction between the first wireless communication device and the second wireless communication device. The polarization planes of the individual antenna elements constituting the microstrip array antenna are set so that the polarization planes are uniform between the directional antenna units,
The orthogonal axis of the adaptive directional antenna unit included in the first wireless communication apparatus is parallel to the horizontal plane, and the orthogonal axis of the adaptive directional antenna unit included in the second wireless communication apparatus is the first wireless. A wireless communication system, wherein the wireless communication system is fixedly installed so as to be orthogonal to an orthogonal axis of an adaptive directional antenna unit included in the communication device. A wireless communication system comprising one first wireless communication device and one or more second wireless communication devices,
The first and second wireless communication devices are:
A one-dimensional microstrip array antenna or a quasi-one-dimensional microstrip array antenna configured by arranging a plurality of one-dimensionally arranged antenna elements in a direction orthogonal to the one-dimensional axis of the microstrip array antenna A plurality of arrayed antennas arranged at predetermined intervals on the orthogonal axis of each of the plurality of microstrip array antennas, and individually transmitting a complex phase to signals transmitted and received by the microstrip array antennas, thereby directing a directional beam in the direction of the orthogonal axis. With an adaptive directional antenna unit to form,
The adaptive directional antenna unit is:
The adaptive directivity is arranged such that the direction of the orthogonal axis in which the microstrip array antennas are arranged is an orthogonal direction between the first wireless communication device and the second wireless communication device. The polarization planes of the individual antenna elements constituting the microstrip array antenna are set so that the polarization planes are uniform between the directional antenna units,
The second wireless communication apparatus is fixedly installed on an upper part of the moving body, and the orthogonal axis of the adaptive directional antenna unit included in the second wireless communication apparatus is orthogonal to the traveling direction of the moving body. The first wireless communication device is fixedly installed at a position overlooking the road on which the moving body travels from the upper part of the building, and the adaptive directional antenna unit of the first wireless communication device includes the first wireless communication device. A radio communication system, wherein an orthogonal axis is arranged so as to be parallel to the road.

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