JPH09200115A - Method for controlling antenna directivity for radio base station in radio communication system and variable directivity antenna - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the control method in which the antenna directivity of a base station in a radio communication system is surely directed in a direction of a desired terminal equipment through simple control. SOLUTION: In the radio communication system making communication between a radio base station 11 with a variable directivity antenna 13 and plural radio terminal equipments 12, the radio base station 11 sends a pilot signal in every direction in a communication service area 14 and a radio terminal equipment 12 measures the reception characteristic of the pilot signal and sends the reception characteristic data to the radio base station 11. The radio base station 12 controls the directivity of the variable directivity antenna 13 based on the reception characteristic data.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radio communication system including at least one radio base station and a plurality of radio terminals, and more particularly to a directivity control method and a directivity control method for a radio base station having a variable directional antenna. The present invention relates to a variable directional antenna capable of controlling the characteristics.

[0002]

2. Description of the Related Art In a wireless communication system composed of at least one wireless base station and a plurality of wireless terminals such as portable mobile terminals moving at low speed, particularly when communication is performed using an existing public network. In order to increase subscriber capacity and communication quality by improving frequency utilization efficiency,
A method of simple space use is adopted. Specifically, by using a sector antenna in the base station, the communication service area of the base station is divided into a plurality of sub-areas called sectors,
There is so-called cell sectorization.

The sectorization of cells by this sector antenna is performed by registering the position of the sector in which the terminal exists in the base station, or by detecting the received signal strength of the transmission signal from the terminal in the base station, The existence direction of the terminal that should communicate with the terminal is limited to some extent, and the effective use of frequency resources is achieved by communicating only in that direction, and the mutual interference of communication between the base station and each terminal is spatially suppressed. This is a method for improving communication quality. Further, this method has a great merit that the transmission power of the base station and the terminal can be reduced.

However, since the sector is fixed in the cell structure using the sector antenna, the flexibility of space utilization is poor. For example, when a large number of subscribers of terminals are concentrated in the cell of the same sector and the communication channel is insufficient, it is possible to flexibly allocate the frequency used in another sector or adjust the sector angle adaptively. There is no way to limit the number of terminals in a sector.

In order to increase the subscriber capacity by making cells into sectors, it is necessary to strictly manage the frequencies used in each sector and each terminal. For that reason, the location registration of each terminal is strictly performed, and when so-called inter-sector handoffs across sectors occur, location registration is reviewed, and control exchanges such as periodic transmission and reception of location registration signals are performed. It has the drawback of becoming complicated.

On the other hand, as a method of avoiding the above-mentioned drawbacks of the cellular radio communication system using the sector antenna, it is conceivable to use an adaptive array antenna for adaptively controlling the communication direction in the base station. An adaptive array antenna is an array in which multiple antenna elements are arranged in a predetermined shape to form an array, and the excitation weight (excitation phase and excitation amplitude) applied to each antenna element is controlled to control the shape and direction of the directivity pattern. That is, the directivity can be adaptively controlled.

When this adaptive antenna technique is applied to a base station, according to an extension of the conventional technique, the directional beam tries to communicate by calculating and setting the optimum excitation weight from the received signal of each antenna element. It is necessary to control the directivity so that it faces the terminal, but the calculation of the excitation weight at this time becomes very complicated.

Further, in this type of wireless communication system, generally, full-duplex communication in which the frequencies of the uplink (terminal → base station) and the downlink (base station → terminal) are different is performed. Here, in the conventional technique, the directivity of the base station antenna is controlled by calculating the direction in which the signal should be transmitted from the propagation state of the uplink signal, that is, the received signal of the base station. However, when the frequencies of the uplink and downlink are different, the propagation state of the downlink signal cannot be accurately known from the uplink signal, so the base station calculates the direction to transmit based on the received signal. However, the terminal does not always exist in that direction. This problem also applies to a wireless communication system that employs a sector antenna, and using a narrow-angle sector antenna causes the same problem as when using an adaptive array antenna. Therefore, a base station using a sector antenna generally does not narrow the sector.

On the other hand, in the conventional adaptive array antenna, the individual excitation weights to be given to the plurality of antenna elements forming the array are obtained by calculation according to the desired directivity, and these are given to give the excitation weights. Set to variable phase shifter, variable attenuator, or variable gain amplifier. Therefore, when the number of antenna elements increases, the calculation of the excitation weight becomes complicated, and as a result, it takes time to control the directivity, and thus it cannot be applied to large-capacity / high-speed communication.

[0010]

As described above, in a wireless communication system composed of a wireless base station and a plurality of wireless terminals, it is possible to increase subscriber capacity and communication quality by improving frequency utilization efficiency. In order to achieve this, it is desirable to form a narrow beam directivity pattern only in the direction of the terminal that should communicate with the base station and perform communication by using cells with a sector antenna or using an adaptive array antenna.

However, in the former case where cells are formed by sector antennas, the communication service area of the base station is fixed, so that the flexibility of space utilization is poor, and frequency control is strictly performed in each sector and each terminal. Because it must be
When an inter-sector handoff occurs, there is a problem in that complicated registration regarding control is required, such as reviewing location registration and transmitting / receiving a location registration signal periodically.

In the latter method using the adaptive array antenna, in addition to the complicated directivity pattern calculation procedure for limiting the direction in which the terminal is present as seen from the base station, a sector antenna is also used. Similar, but
When full-duplex communication is performed, even if the base station calculates the direction to be transmitted based on the received signal, the terminal may not always exist in that direction, so the intended purpose cannot be achieved. is there.

Further, in the conventional adaptive array antenna, since the excitation weights given to a plurality of antenna elements forming the array are calculated and set, the excitation weights are calculated when the number of antenna elements increases. Since it becomes complicated and it takes time to control the directivity, there is a problem that it cannot be applied to a large capacity and high speed communication.

An object of the present invention is to control the antenna directivity of a base station in a wireless communication system so that the terminal for communication can be surely oriented by a simple control, so that the effect of space utilization can be sufficiently exhibited. Another object of the present invention is to provide an antenna directivity control method for a wireless base station in a wireless communication system, which can improve communication quality.

Another object of the present invention is to enable quick control of antenna directivity without requiring complicated calculations, and thus variable directivity suitable as an antenna for a radio base station in a radio communication system as described above. To provide a sex antenna.

[0016]

In order to solve the above problems, the present invention provides a radio base station in a radio communication system for communicating between at least one radio base station having a variable directional antenna and a plurality of radio terminals. In the antenna directivity control method, a wireless base station transmits a pilot signal in all directions within the communication service area of the wireless base station, and the wireless terminal measures the reception characteristic of the pilot signal and transmits the reception characteristic data to the wireless base station. However, the basic feature of the radio base station is to control the directivity of the variable directional antenna based on the reception characteristic data.

By doing so, it is possible to control the directivity of the variable directional antenna of the base station so that the desired wireless terminal can be surely directed by a simple control. That is, in the present invention, the reception characteristic data obtained by the wireless terminal receiving the pilot signal transmitted from the wireless base station is a directivity pattern to be formed in the direction of the wireless terminal by the variable directional antenna of the wireless base station. Therefore, by using this reception characteristic data, the directivity of the variable directional antenna is controlled so as to surely face the wireless terminal.

Therefore, as compared with the case where the cell is formed by the sector antenna, the space utilization effect is sufficiently obtained, and the communication between the radio base station and the desired radio terminal and the communication in the same communication service area are performed. Mutual interference between communication between other wireless terminals and communication performed between a wireless base station and a wireless terminal located close to each other is reduced, and communication quality is improved.

Further, even in full-duplex communication, it is possible to surely know the direction of existence of the wireless terminal as seen from the wireless base station and control the directivity so that the wireless terminal that is trying to communicate is correctly oriented. is there.

Further, even when an adaptive array antenna is used, since the reception characteristic data returned from the wireless terminal to the wireless base station corresponds to the directional beam to be formed in the direction of the wireless terminal, The directivity can be controlled by simple control so that a directional beam can be obtained.

In the present invention, at least one of time division, frequency division and code division can be used as a method of transmitting a pilot signal from the radio base station in all directions within the communication service area.

Here, in particular, when the pilot signal is transmitted from the radio base station in all directions in the communication service area in time division, that is, when the pilot signal is sequentially transmitted in a plurality of directions in the communication service area by the narrow directional beam. Needs to set a time window for the wireless terminal to receive and observe the pilot signal for its own terminal. For this purpose, before transmitting the pilot signal from the radio base station, the timing signal is simultaneously transmitted in all directions in the communication service area using, for example, an omnidirectional pattern, and the timing signal is used as a measurement time reference in the radio terminal. It suffices to measure the reception characteristics of the pilot signal. As another method, after transmitting a timing signal from the wireless base station to all directions in the communication service area on a wireless communication line different from the main wireless communication line of the wireless communication system, a pilot signal is transmitted on the main wireless communication line. Good.

Further, if the communication service area of the radio base station is spatially divided into a plurality of sub-areas and the pilot signal is transmitted at a timing determined in sequence in each sub-area, such a timing signal can be obtained. Need not be sent.

In the wireless terminal, as the pilot signal reception characteristic, specifically, the relationship between the pilot signal transmission direction from the wireless base station and at least one of the received signal strength, the received phase and the signal-to-noise ratio of the pilot signal. To measure. On the other hand, in the wireless base station, based on this reception characteristic data, for example, the antenna directivity is controlled so that a narrow directional beam is formed in the direction in which the maximum reception power is obtained, or the reception power is a predetermined value. When there are a plurality of transmission directions of large pilot signals, a directional pattern having nulls in all or some directions other than the desired direction and a main lobe in the desired direction or in the vicinity thereof is formed. To control the directivity. Also,
The radio base station may control the antenna directivity by facilitating a plurality of directivity patterns in advance in the variable directivity antenna and selecting an optimum directivity pattern from these patterns based on the reception characteristic data. .

The variable directional antenna according to the present invention is provided by a plurality of arrayed antenna elements, an excitation weight imparting means for imparting an excitation weight to the plurality of antenna elements, and the excitation weight imparting means. Storage means for storing information of power excitation weights corresponding to a plurality of types of directivity patterns, and excitation weights for reading information of excitation weights corresponding to desired directivity patterns from the storage means and setting them in the excitation weight imparting means And a setting means. The plurality of antenna elements are arranged on a cylindrical surface, a polygonal prismatic surface, or a spherical surface, and more preferably, the antenna elements are arranged at equal intervals on the same circumference and have the same characteristics.

In the variable directional antenna configured as described above, if a plurality of types of excitation weights are carefully determined in advance by analysis or the like and the information is stored, the directivity control is actually performed. It suffices to read and set the information of the excitation weight. Therefore, the time required for directivity control is short, and the shape of the directional beam can be changed promptly according to the request, which is effective for large-capacity and high-speed communication.

When a plurality of antenna elements are composed of elements having the same characteristics and arranged at equal intervals on the same circumference, the excitation weight setting means transfers the information of the excitation weight read from the storage means to the plurality of antenna elements. It is preferable that the plurality of corresponding excitation weight imparting means can be set with their phases shifted. By doing so, the excitation weight used to form a certain directional beam is set so that the information of the excitation weight is set with a phase shift with respect to the positions of a plurality of antenna elements, so that only the relative position differs. Since it can be shared with the formation of the directional beam, the storage capacity for the information of the excitation weight is small, the storage capacity can be effectively used, and the beam scanning that sequentially shifts the direction of the directional beam is possible. Becomes

The excitation weight setting means sets the excitation weight information read from the storage means while sequentially transmitting the information to the plurality of excitation weight applying means corresponding to the plurality of adjacent antenna elements. This reduces the number of lines for transmitting the excitation weight information,
Since the structure of the power feeding system is simplified, the antenna can be downsized and thinned and the cost can be reduced, and the beam scanning can be realized by a simpler structure.

Further, the excitation weight setting means sets the information of the same excitation weight read from the storage means to the excitation weight giving means corresponding to the two antenna elements located at the point symmetry positions. . By doing so, it is possible to form a line-symmetric directional beam pattern such as a bidirectional beam, and when forming a directional beam in a road direction such as a street cell or a passage direction such as an underground mall, or when a repeater is used. It is also useful for applications such as re-transmission antennas, and the information of the necessary excitation weight is halved, and the storage capacity is further reduced.

[0030]

Embodiments of the present invention will be described below with reference to the drawings. (First Embodiment) FIG. 1 shows a schematic configuration of a wireless communication system according to a first embodiment of the present invention. This wireless communication system is a system for performing communication between at least one wireless base station 11 and a wireless terminal 12 such as a plurality of mobile mobile terminals. The radio base station 11 has at least a variable directional antenna 13 as a transmitting antenna and forms a communication service area 14. When the wireless terminal 12 is located in the communication service area 14, the wireless base station 11
It becomes possible to communicate with. In this communication, the directivity of the variable directional antenna 13 of the wireless base station 11 is controlled so that the directional beam is directed toward the wireless terminal 12.

The variable directional antenna 13 is composed of, for example, an adaptive array antenna, and has a plurality of narrow directional beams, as shown in FIG. 2, 16 narrow directional beams arranged at 22.5 ° intervals in this example. B1 to B16 can be selectively formed, and these narrow directional beams B1 to B16 can cover all 360 ° directions in the communication service area 14 of the radio base station 11. Although the number of narrow directional beams is 16 in the present embodiment, it goes without saying that the number of beams is not particularly limited. In addition, the variable directional antenna 13 is also configured to be able to form an omnidirectional pattern that covers all directions in the communication service area 14 in this embodiment. On the other hand, the antenna 15 of the wireless terminal 12 is usually a simple omnidirectional antenna.

Next, a directivity control method of the variable directivity antenna 13 in this embodiment will be described with reference to FIGS. FIGS. 3A and 3B are flowcharts showing control procedures on the radio base station 11 side and the radio terminal 12 side for the directivity control, respectively. 4 (a) (b)
Is a directivity pattern of the variable directivity antenna 13 during directivity control. 5A and 5B are transmission time tables of the wireless base station 11 and the wireless terminal 12 during directivity control. FIGS. 6A, 6B, and 6C show the pilot signal transmission timing and pilot signal reception characteristics for directivity control. Further, FIG. 7 shows the wireless base station 1.
1 shows the exchange of signals between the wireless terminal 1 and the wireless terminal 12.

First, in the radio base station 11, the directional pattern of the variable directional antenna 13 is set to the omnidirectional pattern B0 as shown in FIG. 4 (a), and in this state, the omnidirectional pilot signal of FIG. 5 (a). In the transmission section 21, the wireless terminal 12
In step S101, a pilot signal (this is referred to as an omnidirectional pilot signal) is transmitted as a timing signal for providing a measurement time reference of the reception characteristic in (1). This omnidirectional pilot signal is received by the wireless terminal 12, and based on this, the wireless terminal 12 starts measuring the reception characteristic of a narrow directional pilot signal, which will be described later (step S20).
1).

Next, in the radio base station 11, step S
After setting n = 1 in 102, the directivity pattern of the variable directivity antenna 13 is set to the narrow directivity beam Bn as shown in FIG. 4B, and in this state, the narrow directivity pilot signal transmission of FIG. During the period 22, a pilot signal (this is called a narrow directional pilot signal) is transmitted (step S10).
3). Then, n is incremented by 1 in step S105, the narrow directivity pattern Bn is sequentially switched to B1 → B2 → ..., And it is repeated until n = 16 in step S104. That is, from the wireless base station 11, FIG.
16 narrow directional pilot signals P1 to P
16 are sequentially transmitted by the narrow directivity patterns B1 to B16. A pulse signal, a CW signal, a modulation signal, or the like is used as the narrow directional pilot signals P1 to P16.

The narrow directional pilot signals P1 to P16 are
The wireless terminals 12 respectively existing in the directions of the narrow directional beams B1 to B16 are received, and the reception characteristics of the narrow directional pilot signals are measured by the wireless terminals 12 (step S2).
03). The reception characteristic of the narrow directional pilot signal is a characteristic relating to the reception power of the narrow band pilot signal such as the reception signal strength, the reception phase (reception complex sample value) and the signal-to-noise ratio. 6B and 6C show the wireless terminal 12.
Is an example of the reception characteristics of the narrow directional pilot signals P1 to P16, and (b) is the reception characteristics of the wireless terminal located in the direction of the narrow directional pilot signal P4,
(C) shows the reception characteristics at the wireless terminal located in the direction of the narrow directional pilot signal P5. FIG.
The horizontal axes of (b) and (c) represent time, that is, the transmission direction of the narrowband pilot signal, and the vertical axes represent the received signal strength (received signal amplitude), the received phase, the signal-to-noise ratio, etc., which will be given thereafter. The parameters are collectively referred to as received power.

Here, when the radio base station 11 sequentially transmits the narrow directional pilot signals P1 to P16, each radio terminal 12 has a time window for receiving and observing the narrow directional pilot signal for its own terminal. Must be set. Therefore, the above-mentioned omnidirectional pilot signal is transmitted from the radio base station 11. That is, since the omnidirectional pilot signal is received at the plurality of wireless terminals 12 in the communication service area 14 almost at the same time, the wireless terminal 12 transmits the omnidirectional pilot signal as a timing signal.
A time window for receiving and observing the narrow directional timing signal transmitted in the narrow directional pilot signal transmission section 22 shown in FIG. 5A is set with this timing signal as a measurement time reference. As a result, the reception characteristic measurement start time of the narrow directional pilot signal in each wireless terminal 12 can be synchronized, and highly reliable measurement becomes possible.

Incidentally, instead of using the omnidirectional pilot signal as a timing signal for setting the reception / observation time window in the narrow directional pilot signal transmission section 22 as described above, the main radio communication line of the present radio communication system is used. Narrow directional pilot signal transmission section 22 using a wireless communication line that can be received in the entire communication service area 14 of the wireless base station 11 other than the above, for example, a line of another wireless communication system such as PHS or PDC. Alternatively, a timing signal for setting a reception / observation time window of the narrow directional pilot signal transmitted to the terminal may be transmitted.

Next, when the reception characteristic of the narrowband pilot signal is measured by the wireless terminal 12 as described above, the reception characteristic data, that is, the data showing the relationship between the transmission direction of the narrowband pilot signal and the reception power is obtained. From the wireless terminal 12 to the wireless base station 1 in the reception characteristic data transmission section 24 of FIG.
1 (step S206). The symbol Q in FIG. 7 indicates the transmission of the reception characteristic data. In addition, FIG.
The reception characteristic data transmission section 24 of No. 2 temporally overlaps the data transmission section T from the radio base station 11 shown in FIG. 5A, but may be a different time zone from the data transmission section T. . Further, the transmission cycle of the narrowband pilot signal may be fixed, but the transmission cycle can be changed according to the change of the radio wave environment or the connection environment of the wireless terminal 12.

When the reception characteristic data transmitted from the radio terminal 12 is received by the radio base station 11, the reception time of the narrowband pilot signal at the radio terminal 12 is received by the radio base station 11 (reception direction). ) And the received power are analyzed, and the direction of the maximum received power, that is, the direction in which the received power of the narrowband pilot signal is maximized is specified based on it (step S108). In the wireless base station 11, as shown by the symbol R in FIG.
When communicating with, the directivity of the variable directional antenna 13 is controlled so that a directivity pattern with a narrow beam width is formed in the specified maximum received power direction (step S10).
8). Then, after this directivity control, communication between the wireless base station 11 and the wireless terminal 12 is started (step S109,
S209).

According to this embodiment, the uplink (radio terminal 12 → radio base station 11) and the downlink (radio base station 11 →
Even in general full-duplex communication in which the frequency of the wireless terminal 12) is different, it is possible to effectively limit the direction in which the wireless terminal 12 exists in the wireless other base station 11 and avoid the emission of radio waves in unnecessary directions. Therefore, it is possible to suppress the interfering interference with other communication. Further, the antenna 15 mounted on the wireless terminal 12 does not need to be a variable directivity antenna, and a simple omnidirectional antenna may be used, so that it is possible to reduce the size and power consumption of the wireless terminal 12.

Next, a concrete configuration example of the radio base station 11 for realizing the above-mentioned directivity control will be described with reference to FIG. The radio base station 11 has a reception antenna 16 provided separately from the variable directivity antenna 13 which is a transmission antenna, and a signal received by the reception antenna 16 is transmitted via a base station reception circuit 17. It is taken out as received data. Further, the reception characteristic data from the wireless terminal 12 received by the receiving antenna 16 is the base station receiving circuit 17
Is input to the antenna directivity control unit 18 via. On the other hand, the transmission data is transmitted from the variable directional antenna 13 to the wireless terminal 12 via the base station transmission circuit 19.
The control unit 20 controls the base station reception circuit 17, the antenna directivity control unit 18, and the base station transmission circuit 19.

Explaining the operation of FIG. 8, the control unit 20 determines the transmission timing of the pilot signal, selects the directivity type of the variable directional antenna 13, and extracts the radio terminal via the base station receiving circuit 17. The reception characteristic data from 12 is transferred to the antenna directivity control unit 18. The base station transmission circuit 19 generates an omnidirectional pilot signal (timing signal) in the omnidirectional pilot signal transmission section 21 of FIG. 5A based on the signal from the control unit 20, and the narrow directional pilot signal transmission section At 22, a narrow directional pilot signal is generated. The antenna directivity control unit 18 sets the directivity pattern of the variable directivity antenna 13 to an omnidirectional pattern in the omnidirectional pilot signal transmission section 21 based on the signal from the control unit 20, and a narrow directional pilot signal transmission section. 22 is switched to the pattern of the narrow directional beam.

When the variable directivity antenna 13 is an adaptive array antenna, the antenna directivity control unit 18
Is to set the excitation weights given to the multiple antenna elements that make up the array.The excitation weights corresponding to the omnidirectional pattern and the narrow directional pattern are stored in a memory as a table, and these are read out as appropriate for excitation. It should be set as a weight giving means. The excitation weight can be added by baseband processing, and the number of high-precision high-frequency components can be reduced. A specific example of an adaptive array antenna suitable for the variable directional antenna 13 will be described later.

Although the receiving antenna 16 is separately provided here, the variable directional antenna 13 can also be used as a transmitting / receiving antenna, which can reduce the number of parts and downsize the wireless base station 11. It can also be realized.

On the other hand, when the reception characteristic data transmitted from the wireless terminal 12 to the reception characteristic data transmitting section 24 of FIG. 5B at the radio base station 11 arrives at the antenna 16 and is received, the reception characteristic data is The signal is taken out via the base station reception circuit 17, switched by a signal from the control unit 20, and guided to the antenna directivity control unit 18. The antenna directivity control unit 18 determines the pattern of the narrow directivity beam suitable for communication with each wireless terminal 12 based on the reception characteristic data as described above, and controls the directivity of the variable directivity antenna 13. Then, in the data transmission section 23 of FIG. 5A or the section after the end of the directivity control, the data is transmitted to the desired wireless terminal 12 for communication.

(Second Embodiment) Next, a second embodiment will be described with reference to FIGS. According to the present embodiment, when the directional beam of the antenna is narrowed, side lobes are generally formed in a direction different from the main lobe in the directional pattern, and the emission of radio waves in an unnecessary direction is forced. This is to reduce the influence on communication. The configuration of the wireless communication system according to the present embodiment, the procedure for transmitting a pilot signal from the wireless base station 11 and the procedure for receiving at the wireless terminal 12 are the same as those in the first embodiment, and a description thereof will be omitted. .

Now, as shown in FIG. 9A, the radio base station 1
Narrow directional pilot signals are transmitted by narrow directional beams having directivity from 1 to different directions one after another, and when the wireless terminals 12 receive the narrow directional pilot signals one after another and measure the reception characteristics, It is assumed that a plurality of large reception powers appear in the reception characteristics as shown in FIG. 9B due to the reflection by the radio wave reflector existing in the vicinity thereof.
In the example of FIG. 9B, as shown by the timings of t1, t2, t15, and t16, B1, B2, B15, and B16 of the 16 narrow directional beams B1 to B16 of FIG. 2 are transmitted. Pilot signals P1, P2, P15, P
A large reception power of a predetermined value or more appears in the reception characteristic of 15. In such a case, in the procedure described in the first embodiment, the radio base station 1
The narrow directional beam of 1 was directed.

By the way, when a reception power larger than a plurality of predetermined values appears in the reception characteristics, any of the narrow directional beams B1, B2, B15, B16 corresponding to these reception powers has sufficient quality and the wireless terminal 12 has sufficient quality. It is possible to communicate with.
In this case, from the wireless base station 11, the wireless terminal 1 is equivalently placed in a wide area indicated by the radio wave radiation direction 30 covered by the set of narrow directional beams B1, B2, B15, B16.
Two appear to exist. Therefore, the wireless base station 11 selects one of the narrow directional beams B1, B2, B15, B16 and transmits it to the desired wireless terminal 12, and the remaining narrow directional beams cause the same frequency to be transmitted. If it is transmitted to another wireless terminal, the radio wave transmitted to the other wireless terminal interferes with the communication between the wireless terminal 12 and the wireless base station 11.

Therefore, in this embodiment, when the wireless base station 11 and the desired wireless terminal 12 communicate with each other, the wireless base station 11 and the wireless base station 11 are wirelessly connected so as not to radiate radio waves in a direction that interferes with the communication to other wireless terminals. In the directivity pattern of the wireless base station 11 used for communication with the terminal 12, a null (zero point) is positively formed in a direction that interferes with communication with other wireless terminals. That is, the directivity pattern of the radio base station 11 shown in FIG. 11A is transformed as shown in FIG. 11B, and the main lobe is provided only in the desired direction in which the desired wireless terminal 12 exists. That is, a directional pattern is formed in which a null is formed in an unnecessary direction that interferes with. As a result, the emission of radio waves in unnecessary directions can be positively reduced, so that it is possible to reduce co-channel interference with other wireless terminals and reduce multipath interference with the wireless terminal itself.

Although it is desired to form nulls in all unnecessary directions in the directional pattern, if it is not possible to form nulls in all unnecessary directions in principle, the nulls are most formed in some unnecessary plural directions. The directional pattern is formed so that the main lobe is easily formed in the desired direction to be emitted. However, in this case, the direction in which the main lobe is formed is not always the direction in which the received power becomes maximum in the reception characteristics of the pilot signal in the wireless terminal 12.

(Third Embodiment) Next, a third embodiment will be described with reference to FIGS. The configuration of the wireless communication system in this embodiment is the same as that in the first embodiment. In this embodiment, similarly to the first embodiment, the wireless terminal 12 receives the pilot signals P1 to P16 transmitted from the wireless base station 11 in different directions in a time division manner, and the wireless terminal 12 receives those pilot signals. The characteristic is measured, and the reception characteristic data is transmitted to the wireless base station 11.
Then, the radio base station 11 searches for a most suitable directivity pattern from a plurality of antenna directivity patterns prepared in advance based on the reception characteristic data, and communicates with the wireless terminal 12 using the directivity pattern. Start.

12 (a) and 12 (b) are flow charts showing control procedures on the radio base station 11 side and the radio terminal 12 side, respectively, relating to the directivity control of the variable directional antenna 13 of the radio base station 11 in this embodiment. And step S
The processes of 101 to S106 and steps S201 to S206 are the same as those of FIGS. In the present embodiment, after the reception characteristic data from the wireless terminal 12 is received by the wireless base station 11 in step S106, the pattern analysis of the reception characteristic data is performed (step S11).
1). The radio base station 11 determines a pre-owned antenna directivity pattern based on the pattern analysis result, and stores a plurality of different pre-owned antenna directivity patterns based on the result. (Directive pattern storage memory) is accessed (step S11
2) Read out a desired antenna directivity pattern and control the directivity of the variable directivity antenna 13 so that the directivity pattern is formed (step S113). After this directivity control, communication between the wireless base station 11 and the wireless terminal 12 is started (steps S109 and S209).

FIG. 13A shows pilot signals P1 to P16 transmitted from the wireless base station 11 to the wireless terminal 12 in step S103, and assuming that the reception characteristics of the pilot signals are those shown in FIG. In S113, FIG.
A directivity pattern as shown in 3 (c) is read.

As described above, according to this embodiment, it is possible to positively reduce the emission of radio waves in unnecessary directions, reduce co-channel interference with other stations, and reduce multipath interference with the local station. Is possible.

(Fourth Embodiment) Next, a fourth embodiment will be described with reference to FIGS. 14 and 15. FIG. 14 is an explanatory diagram of a pilot signal according to this embodiment.
FIG. 5 is a diagram showing the reception timing and reception characteristics of the pilot signal.

In this embodiment, the frequencies of a plurality (16 in the above example) of narrowband pilot signals transmitted from the radio base station 11 are made different as shown by f _{1 to} f ₁₆ in FIG.
These pilot signals are transmitted to all directions within the communication service area of the wireless base station 11 at the same time within a fixed time as shown in FIG. 14 (a) or sequentially shifted as shown in FIG. 14 (b). The point is different from the first embodiment. A pulse signal, a CW signal, a modulation signal, or the like is used as the pilot signal.

In the wireless terminal 12, the pilot signals of the frequencies f _{1 to} f _{16 which} are frequency-separated and transmitted from the wireless base station 11 by the plurality of narrow directional beams B1 to B16 formed by the variable directional antenna 13 are transmitted. Omnidirectional antenna 1
Receive at 5. Specifically, as shown in FIG. 15, the wireless terminal 12 switches the reception frequency to f ₁ at the timing of SW ₁ and receives the pilot signal of the frequency f ₁ transmitted by the narrow directional beam B _1, and keeps constant. SW ₂ after time
The reception frequency is switched to f ₂ at the timing of _{2 and} the pilot signal of the frequency f ₂ transmitted by the narrow directional beam B2 is sequentially received, and all the narrow directional beams B1 to B16 are transmitted respectively. The pilot signals of the frequencies f _{1 to} f ₁₆ are received.

In the wireless terminal 12, the wireless base station 11
The reception characteristics shown in FIG. 15 of the pilot signal from are measured, and the reception characteristics data is transmitted to the radio base station 11. At that time, the omnidirectional antenna 16 is used as the antenna for receiving the reception characteristic data of the uplink (the wireless terminal 12 → the wireless base station 11) in the wireless base station 11, not the variable directional antenna 13. Further, the reception frequency may be the same frequency as any _one of the frequencies f _{1 to} f ₁₆ of the pilot signal or a completely different frequency. In the wireless base station 11, similarly to the previous embodiment, based on the reception characteristic data of the pilot signal from the wireless terminal 12, a narrow directional beam for communication is formed again in the direction in which the wireless terminal 12 exists.

It is obvious that the same effects as those of the first embodiment can be obtained in this embodiment as well. (Fifth Embodiment) Next, a fifth embodiment will be described with reference to FIGS. FIG. 16 is an explanatory diagram of a pilot signal in this embodiment, and FIG. 17 is a diagram showing a reception timing and a reception characteristic of the pilot signal. 18 is a diagram showing a configuration of a portion related to directivity control in the wireless terminal 12.

In this embodiment, the code words of a plurality (16 in the above example) of narrowband pilot signals transmitted from the radio base station 11 are made different as shown by C _{1 to} C ₁₆ in FIG.
These pilot signals are transmitted to all directions within the communication service area of the wireless base station 11 at the same time within a fixed time as shown in FIG. 16 (a), or at different times as shown in FIG. 16 (b). The point is different from the first embodiment. Here, the pilot signal may be a code sequence (code word) that can be separated from each other by utilizing the property of the code, and may or may not be separated by time division or frequency division.

In the wireless terminal 12, the omnidirectional antenna 15 receives the pilot signals of the code words C _{1 to} C ₁₆ transmitted from the wireless base station 11 by the plurality of narrow directional beams B ₁ to B ₁₆ formed by the variable directional antenna 13. To receive. Specifically, as shown in FIG. 18, the wireless terminal 12 uses each codeword C
Matched filters 41-1 to 4-4 for detecting _{1 to} C ₁₆
1-16 and a switch 42 for switching its output. As shown in FIG. 17, the matched filter is switched to 41-1 at the timing of SW ₁ , and the narrow directional beam B
1 receives the pilot signal of the codeword C ₁ transmitted by 1 and switches the matched filter to 41-2 at a timing of SW ₂ after a certain time, and then the codeword C ₂ transmitted by the narrow directional beam B ₂ The operation of receiving the pilot signal is sequentially performed, and all narrow directional beams B1
To B16, the codewords C _{1 to} C respectively transmitted
Receive ₁₆ pilot signals.

In the wireless terminal 12, the wireless base station 11
The reception characteristics shown in FIG. 17 of the pilot signal from are measured and the reception characteristic data is transmitted to the radio base station 11. At that time, the omnidirectional antenna 16 is used as the antenna for receiving the reception characteristic data of the uplink (the wireless terminal 12 → the wireless base station 11) in the wireless base station 11, not the variable directional antenna 13. In the wireless base station 11, similarly to the previous embodiment, based on the reception characteristic data of the pilot signal from the wireless terminal 12, a narrow directional beam for communication is formed again in the direction in which the wireless terminal 12 exists.

It is obvious that the same effects as those of the first embodiment can be obtained in this embodiment as well. (Sixth Embodiment) Next, a directivity control method for the variable directivity antenna 13 in the sixth embodiment will be described with reference to FIGS. 19 (a) and 19 (b) show the radio base station 11 side and the radio terminal 1 related to this directivity control.
It is a flowchart which respectively shows the control procedure at the 2nd side.
20A and 20B are directivity patterns of the variable directivity antenna 13 during directivity control. 21 (a) (b)
Is a wireless base station 11 and a wireless terminal 12 during directivity control.
2 is a transmission timetable of.

In this embodiment, as shown in FIG. 20 (a), there are a plurality of communication service areas of the radio base station 11,
In this example, it is divided into eight sub areas 51 to 58.
The base station 11 has, for these sub-areas 51 to 58,
The pilot signal transmission sections 61 and 6 shown in FIG.
Send a pilot signal to 2, ... The wireless terminal 12 receives and observes the pilot signal until the pilot signal is transmitted to all the sub-areas 51 to 58, and transmits the reception characteristic data to the wireless base station 11 immediately after the end of the reception and observation. By doing so, the wireless terminal 12 is
It becomes unnecessary to transmit the omnidirectional pilot signal for setting the time window for observing the pilot signal for the own terminal as in the embodiment of FIG.

As in the first embodiment, the reception characteristic data is the reception characteristic data transmission section 6 shown in FIG. 21 (b).
5, 66, ... Are transmitted to the radio base station 11, but when there is a lot of uplink traffic, the time of the reception characteristic data, that is, the order of the discrete sampling data series is shifted to the next time, and the next transmission section is transmitted. To the wireless base station 11. This operation has the effect of realizing a flexible wireless communication system according to the traffic of the line.

The control procedure of FIGS. 19A and 19B in this embodiment is the same as that of FIGS. 3A and 3B in the first embodiment.
3A and 3B, except that the omnidirectional pilot signal transmission process (step S101) in the control procedure shown in FIG.

(Seventh Embodiment) Next, an embodiment of a variable directional antenna suitable as a variable directional antenna of the wireless base station 11 in the wireless communication system according to the present invention will be described.

FIG. 22 is an external view of a variable directivity antenna according to the seventh embodiment. A plurality of, in this example, eight antenna elements 101 to 1 are arranged on the peripheral surface of the cylindrical casing 100.
08 are arranged at equal intervals. The method of the antenna element is not particularly limited, but for example, a microstrip antenna configured by forming a strip conductor on a dielectric substrate is suitable. The power feeding system of the variable directional antenna is provided inside the housing 100.

FIG. 23 shows an example of the configuration of the feeding system of the variable directional antenna according to this embodiment. Although FIG. 23 shows the transmission system for simplicity, the reception system has the same configuration. The signal output from the transmitter 149 is the distributor 160.
Are divided into eight, and the weighters 161 to 168 respectively weight, that is, give an excitation weight. Here, weighting refers to setting the relative excitation amplitude and excitation phase of the transmission signal, using a variable amplifier or variable attenuator to change the excitation amplitude, and using a variable phase shifter to change the excitation phase. Can be realized by These excitation amplitude and excitation phase are integrated and called the excitation weight. The weighting units 161 to 168 are controlled by a control signal from the control device 140 to set the excitation weight. The controller 140 also controls the transmitter 149.

The control device 140 is connected to a storage device 150 in which information on a plurality of types of excitation weights is stored in advance. The control device 140 reads out desired excitation weight information from the storage device 150 at any time and supplies it to the weighters 161 to 168. The transmission signals weighted by the weighters 161 to 168 are respectively converted into frequency bands of transmission radio waves by the frequency converters 151 to 158, further amplified by the amplifiers 141 to 148, and then radiated from the antenna elements 101 to 108. It

In the storage device 150, a plurality of types of information about the excitation weights set for the antenna elements 101 to 108 in order to realize a desired directional beam shape are stored in advance as described above. Thus, for example, the formation of a composite pattern of a plurality of beams 1, beam 2 and beam 3 having different directional gains and beam widths in a horizontal plane (X-Y plane) as shown in FIG. 24 corresponds to each pattern. The information of the excitation weights thus read out is read out from the storage device 150 by the control device 140 and weighted by the weighting devices 161 to 168.
It can be realized by setting to.

According to this embodiment, the following advantages can be obtained. (1) A plurality of types of excitation weights are carefully determined in advance by analysis or the like, and the information is stored in the storage device 150. When actually used, the information is read and set in the weighting devices 161 to 168. All you have to do is Therefore,
The time required for forming / controlling the directional beam is short, and the shape of the directional beam can be quickly changed in response to a request. It is effective for future large-capacity / high-speed communication.

(2) The shape of the directional beam to be formed can be freely set only by preparing an excitation weight for that purpose in advance. For example, forming a plurality of sector beams with different beam widths, forming a directivity pattern for lowering side lobes or forming nulls in a specific area (for example, the direction of a radio base station that causes interference), A high gain beam can be formed in a specific direction. From the above,
The beam shape can be flexibly adjusted according to the communication service content, transmission speed, and communication environment, and it is highly effective as an antenna used for advanced communication.

(3) The antenna elements 101 to 108 are arranged at equal intervals on the same circumference and have the same characteristics, specifically, the same antenna system and shape, and their mutual positional relations are symmetrical. There is. Therefore, the excitation weight used to form a certain directional beam can be shared with the formation of another directional beam that differs only in the relative position. For example, in FIG. 25, when the excitation weights given to the antenna elements 101, 102, ... 108 for forming the directional beam a are {w ₁ , w ₂ , ... W ₈ }, this set of excitation weights is one. By shifting the phases one by one to the antenna elements 101, 102, ... 108 by {w ₈ , w ₁ , w ₂ ,
.. w ₇ }, it is possible to form a directional beam b having the same shape as the directional beam a and having a radial direction shifted by 45 ° in the direction of the arrow φ.

In this way, one set of excitation weights can be set by shifting the phases with respect to the plurality of antenna elements 101 to 108. Thus, one set of excitation weights can be set to eight different directional beams. Since it can be used in common, the storage capacity of the storage device 150 can be small and there is an advantage that the limited storage capacity of the storage device 150 can be effectively utilized.

Next, a specific example of control by the control device 140 will be described. Now, one set of excitation weights stored in the storage device 150 is {wa, wb, wc, wd, w
e, wf, wg, wh}. This set of excitation weights is used as the antenna elements 101, 102, 103, 10
By setting them to 4, 105, 106, 107 and 108 respectively, a directional beam of a certain shape (the maximum radiation direction is the φa direction) is formed. As described above, by sequentially setting different antenna elements without changing the order of the set of excitation weights, eight types of directional beams having different radiation directions in the direction of arrow φ in FIG. Can be formed.

As another control method by the control device 140, the directional beam may be sequentially changed on the time axis as shown in FIG. That is, at a certain time t1, a set of excitation weights for the antenna elements 101 to 108 {wa, wb, wc, wd, we, wf, wg, wh}.
Is set to form a directional beam in which the direction of φa is the maximum radiation direction, and the set of excitation weights is {wh, wa, wb, wc, wd, we, w at time t2.
f, wg} are shifted one by one and set sequentially, so that a directional beam shifted by 45 ° in the direction of arrow φ is formed. By performing such an operation sequentially from time t3 to t8, the so-called beam operation is realized by deflecting every 45 ° in the horizontal plane (XY plane) while keeping the shape of the directional beam constant. You can In this case, the unit angle of the beam scanning can be made smaller than 45 ° by increasing the number of antenna elements.

Here, as shown in FIG. 27, for example, there is only one set of excitation weights corresponding to each beam shape, and the set of excitation weights stored in the storage device 50 is the same as the type of beam shape. There are only numbers.

With the above control method, in addition to the effects described above, the deflection of the directional beam in the horizontal plane can be performed by simple control, and the storage capacity can be small. An antenna can be realized. This is effective for application as a radar, and is effective for radiating radio waves for applications such as monitoring of the propagation environment in the wireless communication system for mobile communication described in the above embodiments.

(Eighth Embodiment) FIG. 28 is a diagram showing an example of the configuration of a power feeding system for easily performing the above control. The difference from the configuration of the seventh embodiment shown in FIG. 23 is the control device. 140
The information of the excitation weight is sequentially transferred to the buffers 171 to 178 and then set to the weighters 161 to 168.

Specifically, for example, {wa, wb, wc,
When a set of excitation weights wd, we, wf, wg, wh} is sequentially given to the antenna element arrays 101 to 108 to perform beam scanning, the control unit 140 first inputs information on the excitation weights wh to the buffer 171. . Buffer 1
In 71, the information of the excitation weight wh is transmitted to the phase shifter 161 and the buffer 172 after the unit time Δt. At this time, the information of the next excitation weight wg is input from the control device 140 to the buffer 171. By repeating the same input / output for the excitation weight information,
After Δt, the excitation wait w is stored in the buffers 171 to 178.
The information of a, wb, wc, wd, we, wf, wg, and wh is input, respectively, and after a time Δt, the antenna weights excite the antenna elements 101 to 108.

In this way, the excitation weights wa, wb,
After the antenna elements 101 to 108 are excited by wc, wd, we, wf, wg, and wh, and after a further time Δt, the excitation weight information in the buffer 178 is transferred to the buffer 17.
By operating so as to input 1 to 1, the excitation weight is sequentially transmitted to the adjacent antenna element. As a result, the direction of the directional beam changes at a time interval of Δt, and the beam scanning can be performed in the horizontal plane.

According to the structure of this embodiment, beam scanning in the horizontal plane can be realized with a simple structure. In particular, by providing the buffers 171 to 178, the number of lines for transmitting the information of the excitation weight can be reduced, and the power feeding system becomes simple without a complicated control line. This is convenient for downsizing and thinning the entire antenna, and is also effective for cost reduction.

The case of the variable directional antenna for transmission has been described above, but the variable directional antenna for reception can be realized with the completely same configuration. In the case of reception, the direction of the communication signal is reversed in the configuration of FIG. 23,
The transmitter 149 serves as a receiver, and the distributor 160 serves as a combiner.

(Ninth Embodiment) The variable directional antenna of the present invention can be configured as a transmission / reception shared antenna as well, and a configuration as shown in FIG. 29, for example, is conceivable. A demultiplexer (or switch) 180 is connected to each of the antenna elements 101 to 108, whereby a transmission signal and a reception signal are separated.

At the time of reception, the antenna elements 101 to 108
The signal received by is sequentially input to an amplifier (low noise amplifier) 184, a filter 185, and a frequency converter 186, and an excitation weight is set by a weighter 188, and then combined by a combiner 190 and a receiver 192.
The composite signal is transmitted to. At the time of transmission, the transmission signal from the transmitter 191 is distributed by the distributor 189, and the excitation weight is assigned to the weighter 18 for each of the antenna elements 101 to 108.
After being set by 7, the antenna elements 101 to 108 radiate through the frequency converter 183, the filter 182, and the amplifier (high-power amplifier) 181 in order.

Here, the filters 182 and 185 are for removing interference waves. Weighters 187, 18
8 is controlled by the control device 140, and the excitation weight information is stored in the storage device 150. Control device 140
Are also connected to a transmitter 191 and a receiver 192. With the above-described configuration, the variable directional beam formation and beam scanning as described above can be realized by transmitting and receiving.

(Tenth Embodiment) In the variable directional antenna according to the present invention, the excitation weights corresponding to the antenna elements located at the point symmetry positions can be shared. For example, a pair of antenna elements at the point symmetric positions in FIG. 22, that is, antenna elements 101 and 105, antenna elements 102 and 1
06, antenna elements 103 and 107, and antennas 104 and 108 are set to the same excitation weight. In this case, it is possible to form a directional beam pattern having line symmetry (Y axis symmetry in the case of the example of FIG. 30) represented by a bidirectional beam as shown in FIG.

Such a configuration is effective when forming a directional beam in the direction of a road such as a so-called street cell or in the direction of a passage such as an underground shopping area, and also when receiving from one direction such as a retransmission antenna. It is also highly useful as an application for transmitting generated radio waves in the opposite direction.

In addition, as shown in the example of the excitation weight information stored in the storage device 150 in FIG. 31, according to the present embodiment, the number of excitation weights is halved, which further reduces the storage capacity. is there.

(Eleventh Embodiment) The shape and arrangement of the antenna elements and the number of elements of the variable directivity antenna of the present invention are not limited to those of the embodiments described above. For example, as shown in FIG. 32, by arranging the linear antennas 131 to 138 such as a monopole antenna or a dipole antenna on the same circumference at equal intervals, the same effect as that of the above-described embodiments can be expected. In particular, the configuration of FIG. 32 is effective when operating the antenna with linear polarization (vertical polarization) such as in a mobile phone.

(Twelfth Embodiment) Further, even if the antenna elements 194 are arranged on the same circumference on the disk-shaped substrate 193 as shown in FIG. 33, the same effect as that of the previous embodiments is expected. it can. According to the configuration of FIG. 33, the antenna can be made thin in a planar shape, which is convenient in terms of aesthetics when the antenna is installed on a wall or ceiling for indoor communication. Further, for the same reason, it is also effective as an antenna mounted on a moving body such as an automobile.

As another embodiment, the antenna elements may be arranged on the surface of a polygonal prism instead of being arranged on a cylinder. In this case, the antenna elements are arranged on the sides of the polygon, but the effect is the same. Further, in this case, since the periphery of the antenna element is configured by a plane, a variable directivity is used by using a planar antenna which is easy to manufacture such as a microstrip antenna configured by forming a strip conductor on a dielectric substrate. The antenna can be configured, which is advantageous for cost reduction.

Further, the same effect can be expected when the antenna elements are formed on a curved surface such as a spherical surface and the antenna elements on the same plane are arranged at equal intervals on the same circumference. In this case, since beam formation in a vertical plane other than the horizontal plane is possible, more flexible beam formation is possible, which is effective in expanding the applicable operating range and service area of the communication system.

(Thirteenth Embodiment) In the embodiments of the variable directional antennas up to this point, the case where the weighting is performed in an analog manner has been described. Weighting may be performed by performing.

FIG. 34 is a diagram showing the configuration of the power feeding system of the variable directional antenna according to such an embodiment. The transmission / reception signals of the antenna elements 101 to 108 are branched by the demultiplexer 180, and the received signal is low. The signal is input to the signal processing device 199 through a noise amplifier (or a matrix circuit including a low noise amplifier) 195 and a frequency converter 198 sequentially. The transmission signal is output from the signal processing circuit 199, and transmitted to the antenna elements 101 to 108 through the frequency converter 197 and the high output amplifier (or the matrix circuit including the high output amplifier) 196 in order. Signal processing device 19
In 9, the transmission / reception signal is processed in the baseband and the storage device 1
The process of reading the excitation weight information from 50 and setting the values corresponding to the antenna elements 101 to 108 is performed.
With the above configuration, the excitation weight can be set digitally, which is effective for simplifying and downsizing the power feeding system.

[0097]

As described above, according to the present invention, a pilot signal is transmitted from a wireless base station in all directions within the communication service area of the wireless base station, and the wireless terminal measures the reception characteristics of the pilot signal. By transmitting the reception characteristic data to the radio base station and controlling the antenna directivity based on the reception characteristic data in the radio base station, the antenna directivity of the base station can be controlled easily by ensuring the desired wireless terminal direction. It is possible to control to face. That is, in the present invention, the reception characteristic data obtained by the wireless terminal receiving the pilot signal transmitted from the wireless base station is a directivity pattern to be formed in the direction of the wireless terminal by the variable directional antenna of the wireless base station. Therefore, by using this reception characteristic data, it is possible to control the directivity of the variable directional antenna so as to surely face the wireless terminal.

Therefore, as compared with the case where the cell is formed by the sector antenna, the space utilization effect is sufficiently obtained, and the communication between the wireless base station and the desired wireless terminal and the communication within the same communication service area are performed. Mutual interference between communication between other wireless terminals and communication between neighboring wireless base stations and wireless terminals is reduced, communication quality is improved, and even during full-duplex communication, the wireless base station can be reliably connected. It is possible to clearly know the existing direction of the wireless terminal seen from the above, and it is possible to control the directivity so as to surely face the wireless terminal which is trying to communicate.

Further, even when the adaptive array antenna is used, since the reception characteristic data returned from the wireless terminal to the wireless base station corresponds to the directional beam to be formed in the direction of the wireless terminal, The directivity can be controlled by simple control so that a directional beam can be obtained.

According to the variable directional antenna of the present invention, a simple procedure is prepared in which a plurality of excitation weights are prepared in advance according to the operating condition of the antenna, the information is stored, and the information is read and set. Thus, a desired directional beam pattern can be formed, and the directivity can be quickly changed in response to a request. Therefore, it has high utility value for future large-capacity / high-speed communication.

By arranging a plurality of antenna elements having the same characteristics on the same circumference and using the same set of excitation weights in common for forming beam patterns of the same shape in different directions, It is possible to reduce the capacity of the storage device that stores the information of the excitation weight, which makes it possible to reduce the size of the storage device and effectively use it, and also to perform beam scanning by sequentially shifting the direction of the directional beam. It will be possible.

By setting the excitation weight information while sequentially transmitting it to a plurality of excitation weight applying means corresponding to a plurality of adjacent antenna elements, the number of lines for transmitting the excitation weight information is reduced, and the feeding system Since the configuration is simple, the antenna can be made small and thin, and the cost can be reduced, and the beam scanning can be realized by a simpler configuration.

Furthermore, by setting the same excitation weight for the two antenna elements located at point symmetry, it is possible to form a line-symmetric directional beam pattern such as a bidirectional beam, and It is useful for forming a directional beam in the direction of roads and passageways in underground shopping areas, and for applications such as retransmission antennas, and reduces the necessary excitation weight information by half, further reducing storage capacity. be able to.

[Brief description of drawings]

FIG. 1 is a diagram showing a schematic configuration of a wireless communication system according to a first embodiment.

FIG. 2 is a diagram showing a communication service area of a wireless base station and a shape of a narrow directional beam in the first embodiment.

FIG. 3 is a flowchart showing a control procedure on a radio base station side and a radio terminal side regarding antenna directivity control of the radio base station according to the first embodiment.

FIG. 4 is a diagram showing an antenna directivity pattern during antenna directivity control according to the first embodiment.

FIG. 5 is a diagram showing a transmission time table of a wireless base station and a wireless terminal at the time of antenna directivity control in the first embodiment.

FIG. 6 is a diagram showing transmission timing of pilot signals and reception characteristics of pilot signals for controlling antenna directivity in the first embodiment.

FIG. 7 is a diagram showing exchange of signals between a wireless base station and a wireless terminal according to the first embodiment.

FIG. 8 is a block diagram showing a configuration example of a wireless base station according to the first embodiment.

FIG. 9 is a diagram showing a pilot signal transmission timing and a pilot signal reception characteristic for antenna directivity control in the second embodiment.

FIG. 10 is a diagram for explaining equivalent radio wave radiation directions from a wireless base station according to the second embodiment.

FIG. 11 is a diagram showing an antenna directivity pattern of the wireless base station according to the second embodiment.

FIG. 12 is a flowchart showing a control procedure on the radio base station side and the radio terminal side regarding antenna directivity control of the radio base station according to the third embodiment.

FIG. 13 is a diagram showing a pilot signal transmission timing, a pilot signal reception characteristic, and an antenna directivity pattern for controlling the antenna directivity in the third embodiment.

FIG. 14 is an explanatory diagram of a pilot signal for controlling the antenna directivity in the fourth embodiment.

FIG. 15 is a diagram showing a reception timing and a reception characteristic of a pilot signal in the fourth embodiment.

FIG. 16 is an explanatory diagram of a pilot signal for controlling antenna directivity in the fifth embodiment.

FIG. 17 is a diagram showing a reception timing and a reception characteristic of a pilot signal in the fifth embodiment.

FIG. 18 is a block diagram showing a configuration of a part related to antenna directivity control in a wireless terminal according to a fifth embodiment.

FIG. 19 is a flowchart showing a control procedure on the radio base station side and the radio terminal side regarding antenna directivity control of the radio base station in the sixth embodiment.

FIG. 20 is a diagram showing an antenna directivity pattern during antenna directivity control in the sixth embodiment.

FIG. 21 is a diagram showing a transmission time table of a wireless base station and a wireless terminal at the time of controlling antenna directivity in the sixth embodiment.

FIG. 22 is an external view of a variable directional antenna according to a seventh embodiment.

FIG. 23 is a configuration diagram of a power feeding system of the variable directional antenna according to the seventh embodiment.

FIG. 24 is a diagram showing an example of a directional beam pattern formed by the variable directional antenna according to the seventh embodiment.

FIG. 25 is a diagram showing an example of a directional beam pattern formed by the variable directional antenna according to the seventh embodiment.

FIG. 26 is a diagram showing a control example of excitation weight setting of the variable directional antenna according to the seventh embodiment.

FIG. 27 is a view showing an excitation weight stored in the storage device of the variable directional antenna according to the seventh embodiment.

FIG. 28 is a configuration diagram of a power feeding system of the variable directional antenna according to the eighth embodiment.

FIG. 29 is a configuration diagram of a power feeding system of the variable directional antenna according to the ninth embodiment.

FIG. 30 is a diagram showing an example of a directional beam pattern formed by the variable directional antenna according to the tenth embodiment.

FIG. 31 is a diagram showing an excitation weight stored in the storage device of the variable directional antenna according to the tenth embodiment.

FIG. 32 is an external view of a variable directivity antenna according to the eleventh embodiment.

FIG. 33 is a top view of the variable directional antenna according to the twelfth embodiment.

FIG. 34 is a configuration diagram of a power feeding system of the variable directional antenna according to the thirteenth embodiment.

[Explanation of symbols]

11 ... Wireless base station 12 ... Wireless terminal 13 ... Variable directional antenna 14 ... Communication service area 15 ... Omnidirectional antenna 16 ... Omnidirectional antenna 17 ... Base station receiving circuit 18 ... Antenna directivity control unit 19 ... Base station transmission Circuit 20 ... Control part 30 ... Equivalent radio wave radiation direction 41-1 to 41-16 ... Matched filter 42 ... Changeover switch 100 ... Antenna housing 101-108, 111, 131-138, 194 ... Antenna element 112 ... Phase shift Device 113 ... Variable attenuator 114 ... Feeding circuit 115, 193 ... Substrate 118 ... Input device 119 ... Output device 141-148 ... Amplifier 151-158, 183, 186, 197, 198 ... Frequency converter 161-168, 187, 188 ... Weighting device 140 ... Control device 150 ... Storage device 160, 189 ... Distributor 14 , 191 ... transmitter 171 to 178 ... buffer 180 ... demultiplexer 181,196 ... high output amplifier 184,195 ... low-noise amplifier 182 and 185 ... filter 190 ... combiner 192 ... receiver 199 ... signal processing device

Claims (13)

[Claims] 1. A method for controlling antenna directivity of a wireless base station in a wireless communication system in which communication is performed between at least one wireless base station having a variable directional antenna and a plurality of wireless terminals, the wireless base station comprising: Transmitting a pilot signal in all directions within the communication service area of the station, the radio terminal measures reception characteristics of the pilot signal and transmits reception characteristic data to the radio base station, and the radio base station receives the reception signal. An antenna directivity control method for a wireless base station in a wireless communication system, comprising controlling directivity of the variable directivity antenna based on characteristic data. 2. A method of controlling antenna directivity of a wireless base station in a wireless communication system in which communication is performed between at least one wireless base station having a variable directional antenna and a plurality of wireless terminals, the method comprising: Transmitting a pilot signal by using at least one method of time division, frequency division and code division in all directions in the communication service area of the station, the wireless terminal measures reception characteristic data of the pilot signal to obtain reception characteristic data. Transmitting to the radio base station, the radio base station controlling the directivity of the variable directivity antenna based on the reception characteristic data, an antenna directivity control method for a radio base station in a radio communication system, . 3. A method of controlling antenna directivity of a wireless base station in a wireless communication system for communicating between at least one wireless base station having a variable directivity antenna and a plurality of wireless terminals, the wireless base station comprising: After transmitting the timing signal in all directions within the communication service area, the pilot signals are sequentially transmitted by the narrow directional beam in a plurality of directions within the communication service area, and the wireless terminal uses the timing signal as a measurement time reference for the pilot. The reception characteristic of the signal is measured and the reception characteristic data is transmitted to the radio base station, and the radio base station controls the directivity of the variable directional antenna based on the reception characteristic data. An antenna directivity control method for a wireless base station in a communication system. 4. An antenna directivity control method for a wireless base station in a wireless communication system in which communication is performed between at least one wireless base station having a variable directional antenna and a plurality of wireless terminals, the method comprising: After transmitting a timing signal in a wireless communication line different from the main wireless communication line of the wireless communication system in all directions in the communication service area of the station, and transmitting a pilot signal in the main wireless communication line, the wireless terminal, The reception characteristic of the pilot signal is measured using the timing signal as a measurement time reference, and reception characteristic data is transmitted to the radio base station, and the radio base station directs the variable directional antenna based on the reception characteristic data. Directivity control method for a wireless base station in a wireless communication system, characterized in that the antenna directivity is controlled. 5. A method of controlling antenna directivity of a wireless base station in a wireless communication system for communicating between at least one wireless base station having a variable directivity antenna and a plurality of wireless terminals, the communication service area of the wireless base station. Is spatially divided into a plurality of sub-areas and transmits pilot signals at timings sequentially determined in each sub-area, the wireless terminal measures reception characteristics of the pilot signals and receives reception characteristic data from the radio base station. A radio directivity control method for a radio base station in a radio communication system, wherein the radio base station controls directivity of the variable directivity antenna based on the reception characteristic data. 6. The radio terminal uses, as a reception characteristic of the pilot signal, a relationship between a pilot signal transmission direction from the radio base station and at least one of a pilot signal reception signal strength, a reception phase, and a signal-to-noise ratio. Measuring, the radio base station controls the directivity of the variable directional antenna so that a narrow directional beam is formed in a direction in which a maximum reception power is obtained based on the reception characteristic data. An antenna directivity control method for a wireless base station in the wireless communication system according to any one of claims 1 to 5. 7. The radio terminal uses as a reception characteristic of the pilot signal a relationship between a pilot signal transmission direction from the radio base station and at least one of a reception signal strength, a reception phase and a signal-to-noise ratio of the pilot signal. The measurement, the radio base station, when there is a plurality of transmission directions of the pilot signal having a received power larger than a predetermined value based on the reception characteristic data, null in all or some directions other than the desired direction. The directivity of the variable directivity antenna is controlled so that a directivity pattern having a main lobe is formed in a desired direction or a direction near the desired direction. An antenna directivity control method for a wireless base station in the wireless communication system according to. 8. The directional antenna by the radio base station selecting an optimum directional pattern based on the reception characteristic data from a plurality of directional patterns prepared in advance for the variable directional antenna. The directivity control method of the radio base station in the radio communication system according to claim 1, wherein the directivity of the radio base station is controlled. 9. A plurality of arrayed antenna elements, excitation weight imparting means for imparting excitation weights to the plurality of antenna elements, and a plurality of types of excitation weight information to be imparted by the excitation weight imparting means. Storage means for storing the excitation weight corresponding to the desired directivity pattern from the storage means and setting the excitation weight setting means for setting in the excitation weight giving means. Variable directional antenna characterized by. 10. A plurality of antenna elements having the same characteristics, which are arranged at equal intervals on the same circumference, an excitation weight imparting means for imparting an excitation weight to each of the plurality of antenna elements, and the excitation weight imparting means. Storage means for storing the information of the excitation weight to be imparted by, and excitation weight setting means for reading the information of the excitation weight from the storage means and setting it in the excitation weight imparting means, the excitation weight setting means, Variable directivity, characterized in that the excitation weight information read from the storage means can be set with a phase shift with respect to the plurality of excitation weight application means corresponding to the plurality of antenna elements. antenna. 11. The excitation weight setting means sets while sequentially transmitting the information of the excitation weight read from the storage means to the plurality of excitation weight giving means corresponding to the plurality of adjacent antenna elements. The variable directional antenna according to claim 9 or 10, characterized in that. 12. The excitation weight setting means sets the same excitation weight information read from the storage means to the excitation weight giving means corresponding to two antenna elements located at point symmetry positions. Claim 9 characterized by
Alternatively, the variable directional antenna according to 10 above. 13. The variable directivity antenna according to claim 9, wherein the antenna element is arranged on a cylindrical surface, a polygonal prismatic surface, or a spherical surface.