JP2001320219A - CDMA base station array antenna directivity forming device - Google Patents

Abstract

(57) [Problem] Even if the total number of high-speed transmission mobile stations and low-speed transmission mobile stations exceeds the number of antenna elements, other mobiles including low-speed transmission mobile stations by high-power transmission signals of high-speed transmission mobile stations. Reduce interference and interference with the station. SOLUTION: An arrival direction estimating unit 7-1 to 7-J for estimating an arrival direction of a radio wave from each of a plurality of high-speed transmission mobile stations is provided. The beam direction is directed in the direction of each of the plurality of high-speed transmission mobile stations, and the beam width is determined by a plurality of antenna elements.
A narrow line beam for a high-speed transmission station forming a narrow beam transmitting antenna directivity equal to or smaller than the narrowest beam width among all directivities having a null point that can be formed by the array antenna 1 of 1e1 to 1eM. Directivity forming section 8-1 to 8-
J is provided. A plurality of low-speed transmission-station downlink null-type directivity forming units 9-1 to 9-K for forming transmission antenna directivity with nulls directed toward a plurality of high-speed transmission mobile stations are provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a CDMA base station array / antenna directivity forming device, and more particularly to a plurality of transmission speeds of signals transmitted between a base station and a mobile station which are roughly classified into high speed and low speed. It belongs to a CDMA base station array antenna directivity forming apparatus provided with means capable of responding to the speed.

[0002]

2. Description of the Related Art Code division multiple access (CDMA)
In a CDMA base station that transmits signals to and from each mobile station in a mobile communication system based on the ision multiple access (Ision Multiple Access) system, an array antenna having a plurality of antenna elements arranged is used, and transmission and reception are performed by the plurality of antenna elements. By applying an appropriate weight to the signal for each mobile station, it is possible to form directivity in which a beam is directed toward the mobile station, and reduce interference with other mobile stations. . For example, for each antenna element, directivity for a plurality of mobile stations can be formed simultaneously and independently by adding the product of the signal for each mobile station and the weight for that mobile station by linear addition on a mobile station basis.

Here, in the case of the CDMA system, signals for a plurality of mobile stations are respectively modulated by different codes, so that a signal transmitted by a plurality of antenna elements is modulated by a signal modulated by the same code. By controlling the phases so that they are in phase in a plane orthogonal to the direction of the mobile station, it is possible to form directivity for directing a beam in the direction of the mobile station. Further, in the CDMA system, since the codes of a plurality of mobile stations are selected so that there is no correlation, the directivity for the plurality of mobile stations can be formed simultaneously and independently.

[0004] The above description relates to the downlink where the radio wave is emitted (transmitted) from the base station and received by the mobile station, but the radio wave emitted from the mobile station is received by the base station and the uplink is also transmitted. By making the signals of the same code have the same phase, it is possible to form directivity directed toward the mobile station.

As described above, by forming directivity by using an array antenna, interference with mobile stations other than the transmission target mobile station of interest is reduced. The interference from mobile stations is reduced,
As compared with the omni-cell system or the fixed-sector system base station, there are advantages that the channel capacity can be increased and the communication quality can be improved.

Further, in addition to forming the directivity toward the mobile station of the communication target of interest, a null point is directed to the direction of a mobile station other than the communication target station of interest. In the case of a downlink, even if a strong signal is transmitted to the mobile station of interest and the signal level is narrowed to other mobile stations. Therefore, interference with other mobile stations can be reduced, and in the case of an uplink, a signal from a focused mobile station of interest can be strongly received, and a signal from another mobile station can be used. Interference can be reduced. That is, the signal S of the mobile station of the communication target of interest,
An improvement in the ratio of the interference signal I to the other mobile station (to or from the mobile station) and the SIR can be realized for each mobile station, and the channel capacity increases as in the case described above. This has the advantage of improving communication quality.

As a method of realizing not only the directivity directed to a specific direction but also the directivity having a null point in another direction, a signal from a specific mobile station is S, a specific The sum of the signals of a plurality of interfering mobile stations other than the
When I is set, it can be realized by an algorithm that maximizes SIR, that is, S / ΣI, and as an example, an LMS (Least Mean Square) algorithm is known.

[0008] By using such an algorithm, first, the directivity of the mobile station is directed to the direction of this mobile station by using the uplink signal of each mobile station, and at the same time, the other signals are used. The directivity of the mobile station can be formed such that the null point is directed, and the directivity of the downlink for the mobile station can be formed using the directivity of the uplink.

The number of mobile stations to be serviced for such CDMA base stations tends to increase, and
Since the number of null points that can be formed in the directivity has an upper limit as a property of the antenna, it becomes impossible to direct the null points to all the interfering mobile stations. For example, if the number of antenna elements of the array antenna is M, the number of null points that can be formed is (M-1), and if the number N of interfering mobile stations is larger than (M-1), (N-M + 1) stations Cannot form a null point.

On the other hand, there is a base station adopting the CDMA cellular system, and the base station and the like are configured to support a plurality of transmission speeds roughly classified into a high speed and a low speed. In such a base station, in order to prevent a difference in communication quality including an error rate or the like even when the transmission rate changes, even if the transmission rate changes, noise / interference per bit of data (signal) is reduced. Energy ratio must be kept constant. This means that the transmission power for a mobile station with a high transmission rate is high, and that the mobile station is also transmitting with high power.

[0011] In such a base station, when the number of mobile stations is larger than the number of antenna elements, the directivity of the uplink is determined by directing the beam direction of the directivity to the mobile station of the communication target of interest and increasing the power consumption. It is formed so that the null point is directed to the direction of another high-speed transmission mobile station, and the directivity of the downlink is based on the directivity of the uplink, like this. The beam is formed so that the directional beam is directed toward the mobile station to be communicated, and the null point is directed toward another high-speed transmission mobile station.

FIG. 2 shows an example of such a CDMA base station array / antenna directivity forming apparatus. In this FIG.
Array antenna 1 (including antenna elements 1e1 to 1eM), receivers 3-1 to 3-M,
Also, the transmitters 11-1 to 11-M and the like are displayed.

In this example, first, the common uplink combining section 4
Thus, the signals down-converted into baseband signals by the receivers 3-1 to 3-M are combined and sent to a mobile station selection unit (not shown) to selectively receive a signal from a service area and select this mobile station. Mobile station setting signal HS1
Receivers 3-1 to 3- in accordance with .about.HSJ, LS1 to LSK.
The directivity of each uplink is formed based on the signal from M.

The part that forms the directivity of this uplink is
High-speed signals HS1 to HS of the selected mobile station setting signals
In accordance with J, based on signals from the receivers 3-1 to 3-M, each of a plurality (J, where J ≦ M−1) of high-speed transmission mobile stations (hereinafter, may be simply referred to as high-speed transmission stations). On the other hand, the signal of the high-speed transmission mobile station received with this direction is formed by forming a directivity in which the beam direction is directed toward the high-speed transmission mobile station and becomes null in the direction of the other high-speed transmission mobile station. (HUL1 to HULJ) are output to the corresponding uplink and received according to the uplink adaptive array units 5-1 to 5-J for the high-speed transmission station and the low-speed signals LS1 to LSK among the selected mobile station setting signals. Machine 3-1 to 3-
Based on the signal from M, a plurality (K, in this example, the number of all mobile stations (J + K) is equal to or more than the number M of antenna elements, so that J + K ≧ M, and thus K ≧ M−J) For each low-speed transmission mobile station (hereinafter sometimes simply referred to as a low-speed mobile station), the directivity is such that the beam direction is directed toward the low-speed transmission mobile station and is null in all high-speed transmission mobile stations. And the low-speed transmission station uplink adaptive array sections 6-1 to 6-K for outputting the low-speed transmission mobile station signals (LUL1 to LULK) received in this directivity to the corresponding uplink. It is provided with a configuration.

[0015] The directivity forming part of the downlink first includes the high-speed signals HS1 to HS1 of the selected mobile station setting signal.
Direction-of-arrival estimating units 7-1 to -7 that estimate directions of arrival of radio waves from respective high-speed transmission mobile stations (arrival direction signals HDR1 to HDRJ) based on signals from receivers 3-1 to 3-M according to HSJ. -J and each of the downlink signals HDL1 to HDLJ to each high-speed transmission mobile station,
Based on the HDRJ, the antenna elements 1e1 to 1e1 are directed so that the beam direction is directed toward the high-speed transmission mobile station, and transmission can be performed with an antenna directivity that is null in all other high-speed transmission mobile stations. For 1eM, downlink directivity forming sections 12-1 to 12-12 for high-speed transmission stations that perform distribution control
-J and downlink signals LDL1 to LDL1 to each low-speed transmission mobile station.
Each of the LDLKs is provided with an incoming direction signal HDR1 to HDRJ.
, The beam direction is directed toward the low-speed transmission mobile station, and the antenna element 1e can transmit with a directivity that is null in the direction of all high-speed transmission mobile stations.
For 1 to 1 eM, downlink directivity forming sections 13-1 to 13-K for low-speed transmission stations that perform distribution control, downlink directivity forming sections 12-1 to 12-J for high-speed transmission stations, and low-speed transmission stations The distribution output signals of the downlink directivity forming units 13-1 to 13-K are combined into distribution output signal units for each of the antenna elements 1e1 to 1eM, and the corresponding transmitters (11-1 to 1-1M) are combined.
1-M).

The width of the beam directed to each mobile station (both high speed and low speed) is determined by the position and number of nulls, and is not uniform, and may be narrow or wide. is there.

[0017]

The above-described conventional CDM
In the A base station array / antenna directivity forming apparatus, the total number of high-speed transmission mobile stations and low-speed transmission mobile stations is equal to the antenna element 1e1.
When the number is larger than the number M of １1 eM, on the uplink, for a high-speed transmission mobile station having a large transmission power, the high-speed transmission station uplink adaptive array units 5-1 to 5-J provide:
The beam is directed in the direction of the high-speed transmission mobile station, and has a directivity that is null in the direction of another high-speed transmission mobile station. While the arrays 6-1 to 6-K direct the beam in the direction of the low-speed transmission mobile station and form a directivity that is null in the direction of all high-speed transmission mobile stations, Similarly, for the high-speed transmission mobile station in the downlink, the high-speed transmission station downlink directivity forming unit 12 is used.
-1 to 12-J, directivity is formed such that the beam is directed toward the high-speed transmission mobile station and null in other high-speed transmission mobile stations. Since the beam is directed toward the mobile station and the directivity is null in all high-speed transmission mobile station directions, the directivity of the high-speed transmission mobile station with large transmission power in the downlink is Since the null point is only in the direction of the other high-speed transmission mobile station, the transmission signal component of the high-speed transmission mobile station is radiated in the direction of the low-speed transmission mobile station. There is a problem that the communication quality is degraded due to interference.

In view of the above-mentioned problems of the prior art, an object of the present invention is to provide a high-power transmission mobile station that uses a high-power transmission signal when the total number of high-speed transmission mobile stations and low-speed transmission mobile stations is equal to or greater than the number of antenna elements. Another object of the present invention is to provide a CDMA base station array / antenna directivity forming apparatus capable of reducing interference and interference with other mobile stations including low-speed transmission mobile stations and improving the communication quality thereof.

[0019]

SUMMARY OF THE INVENTION A CDMA base station array antenna directivity forming apparatus according to the present invention is received by an array antenna of a base station in a CDMA mobile communication system in which a plurality of antenna elements are arranged. Uplink directivity forming means for performing control based on receiving antenna directivity for signals of a plurality of high-speed transmission mobile stations and low-speed transmission mobile stations. For a transmission signal, comprising downlink directivity forming means for performing control based on transmission antenna directivity, and the total number of the plurality of high-speed transmission mobile stations and low-speed transmission mobile stations is equal to or greater than the number of antenna elements of the array antenna. A CDMA base station array / antenna directivity forming apparatus, wherein the downlink directivity forming apparatus is provided to achieve the above object. Stage, and having each of the following configurations. (A) an arrival direction estimating unit for estimating an arrival direction of a radio wave from each of the plurality of high-speed transmission mobile stations based on a signal received by the array antenna (b) a downlink to the plurality of high-speed transmission mobile stations For each line signal, the beam direction is directed toward the high-speed transmission mobile station based on the direction of arrival of the radio wave estimated by the direction-of-arrival estimating unit, and the beam width is changed to an array antenna by the plurality of antenna elements. A plurality of downlinks for high-speed transmission mobile stations that are controlled so that transmission is performed with a narrow beam transmission antenna directivity equal to or smaller than the narrowest beam width of all the directivities having null points that can be formed by Beam directivity forming section (c) Nulls in all directions of the plurality of high-speed transmission mobile stations estimated by the direction-of-arrival estimation section for each of the downlink signals to the plurality of low-speed transmission mobile stations. Controls to be transmitted in directivity becomes, down a plurality of low-speed transmission the mobile station lines null type directivity forming section

In addition to the CDMA base station array / antenna directivity forming apparatus, when the number of high-speed transmission mobile stations is equal to or greater than the number of antenna elements of the array antenna, a maximum of the high-speed transmission mobile stations is used. A high-speed transmission mobile station selecting means for selecting and setting the number of high-speed transmission mobile stations one less than the number of antenna elements, and providing a plurality of low-speed transmission mobile station downlink null-type directivity forming units. A plurality of high-speed transmission mobile stations to be directed are selected and set as the number of high-speed transmission mobile stations selected by the high-speed transmission mobile station selection means.

[0021]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention is directed to a downlink directivity forming means when the total number of a plurality of high-speed transmission mobile stations and low-speed transmission mobile stations is equal to or more than the number of antenna elements of an array antenna. An arrival direction estimating unit for estimating an arrival direction of radio waves from each of the plurality of high-speed transmission mobile stations, based on signals received by the array antenna, and a downlink signal to each of the plurality of high-speed transmission mobile stations. Based on the direction of arrival of the radio wave estimated by the direction-of-arrival estimation unit, the beam direction is directed toward the high-speed transmission mobile station, and the beam width is set to an array of the plurality of antenna elements.
A plurality of downlinks for high-speed transmission mobile stations, which are controlled so that transmission is performed with a transmission antenna directivity of a narrow beam equal to or smaller than the narrowest beam width of all directivities having a null point that can be formed by an antenna. A line narrow beam directivity forming unit;
For each of the downlink signals to the plurality of low-speed transmission mobile stations, control is performed such that the signals are transmitted with null directivity in all directions of the plurality of high-speed transmission mobile stations estimated by the arrival direction estimation unit. And a downlink null directivity forming unit for a low-speed transmission mobile station.

With this configuration, since the high-power transmission signal of the high-speed transmission mobile station is a narrow beam directional transmission, the total number of the high-speed transmission mobile station and the low-speed transmission mobile station is equal to or more than the number of antenna elements. Including low-speed transmission mobile stations to which the null point is not directed, interference and interference with other high-speed transmission mobile stations can be reduced, and the communication quality can be improved. If the transmission power from the station does not change, the reception level can be increased, the communication quality of the high-speed transmission mobile station can be improved, and if the reception signal level is the same, the transmission from the base station can be improved. The power can be reduced and as a result
Further, interference and interference with other mobile stations can be reduced. In addition, since the transmission signal of the low-speed transmission mobile station is transmitted with directivity pointing toward the high-speed transmission mobile station, interference with the high-speed transmission station due to this transmission signal is reduced, leading to improvement in communication quality. If the communication quality only needs to be maintained at a certain level, the transmission power to the high-speed transmission mobile station can be reduced, and interference and interference with other mobile stations can be reduced.

As described above, the transmission power to the high-speed transmission mobile station requiring high power transmission is achieved by the narrow beam directional transmission to the high-speed transmission mobile station and the high-speed transmission station directional null-type directional transmission to the low-speed transmission mobile station. , It is only necessary to reduce interference and interference with other mobile stations, and it is possible to increase communication capacity by reducing power.

[0024]

Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing one embodiment of the present invention. In this embodiment, the array antenna 1, the antenna duplexers 2-1 to 2-M, the receivers 3-1 to 3-M, the common uplink combining unit 4, and the uplink adaptive array unit 5 for high-speed transmission stations are used. 1 to 5-J, low-speed transmission station uplink adaptive array units 6-1 to 6-K, arrival direction estimation units 7-1 to 7-J, combining unit 10, and transmitters 11-1 to 11-1
1-M performs the same function as that shown in FIG.
Uplink adaptive array section 5-1 for high-speed transmission station
5-J and the low-speed transmission station uplink adaptive array units 6-1 to 6-K constitute uplink directivity forming means.

The down-link directivity forming means in this embodiment comprises the above-mentioned arrival direction estimating units 7-1 to 7-J and the high-speed transmission of the down-link signals HDL1 to HDLJ to a plurality of high-speed transmission mobile stations. Mobile station arrival direction signal (HDR
1 to HDRJ), the beam direction is directed to the direction of the high-speed transmission mobile station, and the beam width is set to an array of a plurality of antenna elements 1e1 to 1eM.
Distribution control is performed on each of the antenna elements 1e1 to 1eM so that transmission can be performed with a transmission antenna directivity of a narrow beam equal to or smaller than the narrowest beam width of all directivities having null points that can be formed by the antenna 1. A plurality of high-speed transmission station downlink narrow beam directivity forming units 8-1 to 8-J;
Downlink signals LDL1 to LD to a plurality of low-speed transmission mobile stations
Distribution control is performed on each of the antenna elements 1e1 to 1eM based on the direction-of-arrival signals HDR1 to HDRJ such that the LK can be transmitted with a transmission antenna directivity that is null in all directions of a plurality of high-speed transmission mobile stations. , A plurality of low-speed transmission station downlink null directivity forming units 9-1 to 9-K
And the distributed output signals of the plurality of downlink narrow beam directivity forming units for high-speed transmission stations 8-1 to 8-J and the plurality of downlink null-type directivity forming units for low-speed transmission stations 9-1 to 9-K, And a combining unit 10 that combines the distribution output signal units for the antenna elements 1e1 to 1eM and supplies the resultant signals to the corresponding transmitters (11-1 to 11-M).

In this embodiment, transmission signals to a plurality of high-speed transmission mobile stations requiring high-power transmission are transmitted by narrow-beam directivity forming sections 8-1 to 8 -J for high-speed transmission stations. Therefore, even if the total number (J + K) of the high-speed transmission mobile stations and the low-speed transmission mobile stations is equal to or more than the number of antenna elements M, a null signal is transmitted by the transmission signal from the high-speed transmission mobile station of interest. Interference and interference with other high-speed transmission mobile stations, including a plurality of low-speed transmission mobile stations that cannot be pointed, can be reduced, the communication quality can be improved, and the transmission power from the base station can be improved. If the level does not change, the reception level can be increased by the narrow beam, and the communication quality of the high-speed transmission mobile station can be improved. Conversely, if the reception level is not changed, the transmission power level from the base station can be reduced by the narrow beam, and as a result,
Interference and interference with a plurality of low-speed transmitting mobile stations and other high-speed transmitting mobile stations can be further reduced.

In this embodiment, the transmission signal to the low-speed transmission mobile station is transmitted in all directions by the low-speed transmission station downlink null-type directivity forming units 9-1 to 9-K. Is transmitted in a directivity in which null is directed to the mobile station, so that interference with the high-speed transmission mobile station due to the transmission signal to the low-speed transmission mobile station can be reduced, and the communication quality can be improved. If the quality is maintained at a constant level, the transmission power level to the high-speed transmission mobile station can be reduced accordingly, and interference and interference with other mobile stations can be reduced.

As described above, the transmission power to the high-speed transmission mobile station by the narrow beam directional transmission to the high-speed transmission mobile station and the high-speed transmission mobile station direction null-type directional transmission to the low-speed transmission mobile station in the downlink. The reduction in the level can reduce the interference and interference with other mobile stations and improve the communication quality. Furthermore, the reduction of the transmission power level to the high-speed transmission mobile station requiring high power transmission can reduce the total power consumption in the base station and increase the communication capacity accordingly.

In this embodiment, when the sum of the number J of high-speed transmission mobile stations and the number K of low-speed transmission mobile stations is equal to or greater than the number M of antenna elements, the number J of high-speed transmission mobile stations is equal to the number of antenna elements. If the number is less than the number M, null can be directed in all directions of the high-speed transmission mobile station in the null-type directivity to the low-speed transmission mobile station.
Is larger than the number M of antenna elements, since the maximum number of null points that can be formed in the directivity is (M-1), there are high-speed transmission mobile stations to which nulls cannot be directed.

In this case, the maximum number of antenna elements M
Select one (M-1) of the high-speed transmission mobile stations smaller by one,
A high-speed transmission mobile station selecting means is provided for setting, the direction in which the null is directed to the transmission antenna directivity to each low-speed transmission mobile station by the low-speed transmission station downlink null-type directivity forming units 9-1 to 9-K. Is the direction of the (M-1) high-speed transmission mobile stations selected and set by the high-speed transmission mobile station selection means. In the direction-of-arrival estimating units 7-1 to 7-J and the high-speed transmission station downlink narrow beam directivity forming units 8-1 to 8-J, (M-1) selected and set and other It covers all high-speed transmission mobile stations. Therefore, the block diagram of this part is different from that of FIG. 1 is the same as FIG. 2 of the conventional example, and since J ≦ (M−1), the other parts are also different from FIG. 1. However, when J ≧ M, Portions forming null-type directivity (5-1 to 5-J, 6-1 to 6-K, 9-1 to 9
For -K), a directivity in which nulls are directed to the direction of the selected and set high-speed transmission mobile station may be used, and therefore, illustration thereof is omitted.

Also in this case, the effect of the narrow beam directivity and the effect on the null-pointed mobile station are as follows:
This is the same as the previous embodiment.

[0032]

As described above, the present invention estimates the direction of arrival of radio waves from each of a plurality of high-speed transmission mobile stations,
For each of the plurality of high-speed transmission mobile stations, the beam direction is directed in the direction, and the beam width is the narrowest beam width among all directivities having a null point that can be formed by an array antenna with a plurality of antenna elements. A configuration in which transmission is performed with a narrow beam transmission antenna directivity equal to or smaller than that of the transmission antenna, and for each of a plurality of low-speed transmission mobile stations, transmission is performed with a transmission antenna directivity in which nulls are directed toward a plurality of high-speed transmission mobile stations. As a result, the total number of mobile stations becomes equal to or larger than the number of antenna elements, thereby reducing interference and interference caused by transmission signals of the high-speed transmission mobile station with respect to the high-speed transmission mobile station, including the low-speed transmission mobile station to which the null point is not directed. The communication quality can be improved, and by using a narrow beam, the reception level can be increased and the communication quality can be improved or the transmission power can be reduced. This has the effect of further reducing interference and interference with the mobile station. The antenna directional transmission from the low-speed transmission mobile station with nulls directed toward the high-speed transmission mobile station enables high-speed transmission mobile communication. This has the effect of reducing interference and interference with the station, and has the effect of reducing the transmission power from the high-speed transmission mobile station. The effect is that it is possible to measure the increase in

[Brief description of the drawings]

FIG. 1 is a block diagram showing one embodiment of the present invention.

FIG. 2 is a block diagram showing an example of a conventional CDMA base station array / antenna directivity forming apparatus.

[Explanation of symbols]

Reference Signs List 1 array antenna 1e1 to 1eM antenna element 2-1 to 2-M antenna duplexer 3-1 to 3-M receiver 4 common uplink combining unit 5-1 to 5-J uplink adaptive transmission / reception for high-speed transmission station
Array unit 6-1 to 6-K Uplink adaptive low-speed transmission station
Array unit 7-1 to 7-J Arrival direction estimating unit 8-1 to 8-J Downlink narrow beam directivity forming unit for high-speed transmission station 9-1 to 9-K Downlink null directivity forming for low-speed transmission station Unit 10 Combining unit 11-1 to 11-M Transmitter 12-1 to 12-J Downlink directivity forming unit for high-speed transmission station 13-1 to 13-K Downlink directivity forming unit for low-speed transmission station

Claims (2)

[Claims] 1. A base station in a CDMA mobile communication system receives signals from a plurality of high-speed transmission mobile stations and low-speed transmission mobile stations received by an array antenna having a plurality of antenna elements arranged therein. Uplink directivity forming means for performing control based on antenna directivity,
Downlink directivity forming means for performing control based on transmission antenna directivity for transmission signals to the plurality of high-speed transmission mobile stations and the low-speed transmission mobile stations, respectively. CDM when the total number of mobile stations is equal to or greater than the number of antenna elements of the array antenna
A base station array / antenna directivity forming apparatus, wherein said downlink directivity forming means has the following configurations. (A) an arrival direction estimating unit for estimating an arrival direction of a radio wave from each of the plurality of high-speed transmission mobile stations based on a signal received by the array antenna (b) a downlink to the plurality of high-speed transmission mobile stations For each line signal, the beam direction is directed toward the high-speed transmission mobile station based on the direction of arrival of the radio wave estimated by the direction-of-arrival estimating unit, and the beam width is changed to an array antenna by the plurality of antenna elements. A plurality of downlinks for high-speed transmission mobile stations that are controlled so that transmission is performed with a narrow beam transmission antenna directivity equal to or smaller than the narrowest beam width of all the directivities having null points that can be formed by Beam directivity forming section (c) Nulls in all directions of the plurality of high-speed transmission mobile stations estimated by the direction-of-arrival estimation section for each of the downlink signals to the plurality of low-speed transmission mobile stations. Controls to be transmitted in directivity becomes, down a plurality of low-speed transmission the mobile station lines null type directivity forming section 2. The CDMA base station array according to claim 1,
In addition to the antenna directivity forming device, when the number of high-speed transmission mobile stations is equal to or more than the number of antenna elements of the array antenna, the maximum number of these high-speed transmission mobile stations is one smaller than the number of antenna elements. A plurality of high-speed transmission mobile stations provided with high-speed transmission mobile station selection means for selecting and setting a high-speed transmission mobile station, and a plurality of low-speed transmission mobile station downlink null-type directivity forming units serving as targets of directivity null direction. CDMA base station array / antenna directivity forming apparatus, wherein the number of high-speed transmission mobile stations selected and set by the high-speed transmission mobile station selection means are set as the high-speed transmission mobile stations.