JP2002111556A - Base station device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To save power and reduce interference amount. SOLUTION: A 120 deg.-beam antenna 33 and an antenna means, comprising two 60 deg.-beams 27 and 28 consisting of antennas 31 and 32 and a hybrid 34 of which antenna means substantially covers the service area thereof are installed. The movement speed of a mobile station is determined from the fading pitch of radio waves received from the mobile station, and whether the mobile station is present in the direction of the beam 27 or in the direction of the beam 28 is detected from the phase difference between signals received through ports 34a and 34b of the hybrid 34 by a device 54. The result of the detection is made reference to. If the movement speed is equal to or greater than a prescribed value, a control device 26 allocates one of transmitter-receivers 37-1 to 37-L, that can perform transmission from the 120 deg.-beam antenna 33. If the movement speed is less than the specified value, the control device allocates one among transmitter-receivers 48-1 to 48-N or 43-1 to 43-M, that can transmit from the antenna beam 27 or 28, depending on the direction of the mobile station.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a base station device used in a mobile communication system, and more particularly to reducing the radiated power and the amount of interference.

[0002]

2. Description of the Related Art In actual operation of mobile communication, not only users (users) who move at high speed during a call time and switch channels many times, but also many users complete a call without moving. However, the mobile communication base station apparatus uses an antenna having the same wide-angle directivity in all of a plurality of channels and time slots because it is assumed that a service during high-speed movement is provided to all users. Therefore, when starting communication with a specific user, the base station radiates radio waves in a direction other than the direction in which the user exists in the service area, for example, the sector, and wastes power. . As described above, when an antenna having the same wide-angle directivity is used in all the channels and time slots, there is a problem from the viewpoint of a radio wave environment and energy saving. On the other hand, a method has been proposed in which a narrow-angle directivity characteristic (referred to as a narrow beam) is generated for each channel / time slot using an array antenna, and tracking is performed so that the narrow beam is always directed toward the user. Although this method is excellent from the above viewpoint, there is a problem that the installation area and the device scale of the array antenna are increased. Further, a complicated signal processing system is required.

FIG. 7 shows a configuration of a conventional base station apparatus. The receiving antenna 11 and the transmitting / receiving antenna 12 are directed in the same direction with the main beam width of the directional characteristic being 120 °, and the receiving antenna 11 is directly connected to the combining / distributing unit 13, and the transmitting / receiving antenna 12 is combined and distributed via the duplexer 14. Connected to the vessel 13. Transmission / reception devices 15-1 to 15 for control channels and communication channels of channels f11 to f1L
−L transmitters 16 are connected to the transmission ports of the combiner / splitter 13, and the receivers 17 and 18 are respectively connected to the combiner / splitter 13.
Are connected to the respective reception ports of the antennas 11 and 12, respectively, so that transmission and reception of a control channel and a communication channel are enabled. Each transmitter 22 of the communication channel transmitting / receiving devices 21-1 to 21-M of the channels f21 to f2M is connected to a transmission port of the combiner / distributor 13, and each receiver 23, 24 is connected to the antenna 11, 12 of the combiner / distributor 13. Are connected to the respective reception ports, and transmission / reception of a communication channel is enabled. Each of the receivers 17 and 18 is adapted to perform diversity reception, and each of the receivers 23 and 24 is also adapted to perform diversity reception.

FIG. 8A shows the time slots used by the transmission / reception devices 15-1 to 15-L.
FIG. 8B shows the time slots used by. The beam width of the antenna 12 used for each transmission is 120 °,
That is, the same beam is used for all the channels and time slots. In addition, the base station controller 26 allocates a channel for which of the transmitting / receiving apparatuses 15-1 to 15-L and 21-1 to 21-M performs communication in which time slot.

[0005]

As described above, in the conventional base station, since the wide-angle beam antenna is fixedly allocated to all the channels, a desired mobile station within the service area (for example, sector) is located. This means that wasteful radiated power is consumed in directions other than the direction in which it is located, and the amount of interference with other base stations also increases. In view of the above, an object of the present invention is to provide a base station apparatus capable of reducing the radiated power and the amount of interference as compared with the related art.

[0006]

According to the present invention, there is provided one wide-angle beam antenna and a plurality of narrow-angle beam antennas covering the service area thereof.
It detects the moving speed of the mobile station and in which narrow-angle beam direction it exists, and based on this information, if the moving speed is high, the transmission and reception for a communication channel capable of transmitting power to the wide-angle beam antenna means. If one of the devices is assigned, and the moving speed is slow, a transmitting / receiving device for a communication channel capable of transmitting power to the narrow-angle beam antenna means in the direction in which the mobile station is located is assigned.

[0007]

FIG. 1 shows an embodiment of the present invention.
12 with two 60 ° beam (narrow angle beam) antenna means
In addition to covering the sector service area of 0 °, the 120 ° beam (wide-angle beam) antenna 33 covers the 120 ° sector service area and the antenna 3
This is a case where diversity reception is enabled by antennas 1 and 32 and an antenna 33. The antennas 31 and 32 are connected to the combining / distributing device 13 via a hybrid 34 and further via duplexers 35 and 36.
Reference numeral 3 is connected to the combiner / distributor 13 via the duplexer 14. Each of the combined directional characteristic main beams 27 and 2 when the antennas 31 and 32 are viewed from the ports 34 a and 34 b of the hybrid 34 to which the duplexers 35 and 36 are connected, respectively.
8 have a beam width of 60 °, and these beams 2
7 and 28 are directed to the left and right sides in the figure, and the main beam 29 of the antenna 33 has a beam width of 120 ° and almost covers the beams 27 and 28. That is, the antennas 31 and 3
2 and the hybrid 34 constitute two 60 ° beam (narrow angle beam) antenna means.

[0008] Transceiver devices 37-1 to 37-3 for wide-angle beams of channels f11 to f1L, control channels and communication channels.
Each of the 7-L transmitters 38 can transmit and supply power to the 120 ° beam antenna 33 via the combiner / splitter 13 and the duplexer 14, and the receivers 39 and 41 respectively combine the combiner / splitter 13 and the duplexers 36 and 35. , Receiving and feeding power to the ports for the 60 ° beams (hereinafter referred to as 60 ° beam ports) 34 a and 34 b of the hybrid 34, and the respective receivers 42 via the combiner / splitter 13 and the duplexer 14. Reception power can be supplied to each of the 120 ° beam antennas 33.

The first narrow-angle beams of the channels f21 to f2M and the respective transmitters 44 of the communication channel transmitting / receiving devices 43-1 to 43-M are transmitted through the combining / distributing device 13 and the duplexer 35 to the 60 ° beam port of the hybrid 34. 34a, and each receiver 45 includes a hybrid 47, a combiner / divider 13, a duplexer 35,
36, both the 60 ° beam ports 34a and 34b of the hybrid 34 can be received and supplied.
Each of the receivers 46 can receive and supply power to the 120 ° beam antenna 33 via the combiner / splitter 13 and the duplexer 14, respectively.

The second narrow-angle beams of the channels f31 to f3N and the transmitters 49 of the communication channel transceivers 48-1 to 48-N are transmitted via the combining / distributing device 13 and the duplexer 36 to the 60 ° beam port of the hybrid 34. 34b, and each receiver 51 includes a hybrid 53, a combiner / distributor 13, and duplexers 35 and 36.
Through both 60 ° beam ports 3 of the hybrid 34
4a and 34b can be supplied with reception power, respectively.
The receiver 52 can receive and supply power to the 120 ° beam antenna 33 via the combiner / splitter 13 and the duplexer 14.

[0011] Receivers 39, 41, 42 for the control channel
Is also supplied to the beam selection information detecting device 54, and the beam selecting device 54 detects that the direction of the receiving mobile station is 60 °.
The direction of the beam 27 or the direction of the 60 ° beam 28 is determined by comparing the reception levels of the receivers 39 and 41, and the movement of the mobile station is determined from the fluctuation of the reception level of the receiver 42, that is, the fading pitch Tf. Detect speed information. 12
Transmitter / receiver for 0 ° control channel and communication channel 37−
All time slots from 1 to 37-L are 1 as shown in FIG. 2A.
20 ° beam. On the other hand, as shown in FIG. 2B, all the time slots of the 60 ° communication channel transmitting / receiving apparatuses 43-1 to 43-M are assigned right beams, and the time slots of the 60 ° communication channel transmitting / receiving apparatuses 48-1 to 48-N are allocated. Are all assigned the left beam as shown in FIG. 2c. Less than,
The operation will be described.

When assigning a communication channel for outgoing / incoming calls or the like, the base station controller 26 uses the beam selection information detecting device 54
Is inquired about moving speed information (fading pitch Tf) and beam information. The base station controller 26 performs a process as shown in FIG. 3A based on the response information. If Tf is larger than a certain value, the mobile station determines that the mobile station is moving at high speed, and the transmitting / receiving apparatuses 37-1 to 37-L having a 120 ° beam communication channel.
Is assigned. On the other hand, if Tf is smaller than a certain value, the mobile station is regarded as stationary or moving at a low speed, and the transmitting / receiving apparatuses 43-1 to 43-M or 48- having a 60 ° beam communication channel.
1 to 48-N. The direction of the mobile station is detected from the signals received from the ports 34a and 34b of the hybrid 34, and the right beam 27 or the left beam 28 is determined according to the information.
Assign from one of 3-1 to 43-M and 48-1 to 48-N. These transmitting / receiving apparatuses 43-1 to 43-M, 48-1 to 4-4 are provided only to mobile stations determined to have a low moving speed.
Since 8-N is not allocated, the probability of the channel switching operation occurring is low, and therefore, the transmitting / receiving apparatuses 43-1 to 43-3 are not allocated.
The beam selection information detecting device 54 is not connected to -M, 48-1 to 48-N.

Transmission / reception devices 37-1 to 37-L and 43-1 to 43-M, 4
It is possible to minimize the beam splitting loss by adaptively setting the ratio of the numbers of 7-1 to 48-N. In this embodiment, the transmitting beam is set to 120 ° and two 60 °. However, the receiving beam may be formed to be a 120 ° beam and two 60 ° beams as in the transmission. In FIG. 1, the beams are combined using the hybrids 47 and 53 and received as a 120 ° beam. 60 ° beam transmitting / receiving devices 43-1 to 43-M, 48-1 to 48
−N is 120
° 3 dB compared to the beam transceivers 37-1 to 37-L
The transmission power is low. The coverage of the service area by the 120 ° beam (layer 1), the coverage of the service area by two 60 ° beams (layer 2), the coverage of the service area by four narrower 30 ° beams (layer 3), and the layer , The transmission power can be reduced as shown in FIG. 3B. In FIG. 3B, the transmission power can be set to 0 dB in the layer 1, −3 dB in the layer 2, and −6 dB in the layer 3.

FIG. 4 shows an example in which the configuration for diversity is omitted from the configuration shown in FIG. That is, in this example, the 120 ° beam antenna 33, the duplexer 14, and the receivers 42 and 4 in FIG.
6, 52 are omitted. The transmitters 38 of the 120 ° control channel and communication channel transmitting / receiving devices 37-1 to 37 -L are further connected via the hybrid 56 to the combining / distributing device 1.
3. Hybrid 3 via duplexers 35 and 36
4 can transmit power to both 60 ° beam ports 34a and 34b, and thereby can transmit power to the 120 ° beam antenna means. That is, transmission (and reception) can be performed by each of the plurality of narrow-angle beam antenna units, and transmission and reception of one wide-angle beam antenna unit can be performed using the plurality of narrow-angle beam antenna units.

Further, one 60 ° communication channel transmitting / receiving device 48-1 to 48-N in FIG.
The transmitter 38 of the communication channel transceivers 43-1 to 43-M may be switched to the 60 ° beam ports 34a and 34b to supply power for transmission. An example is shown in FIG. The transmitter 44 is enabled by a switch 58 to be switchably connected to the 60 ° beam ports 34a and 34b. All the time slots of the 120 ° control channel and communication channel transceivers 37-1 to 37-L are 120 ° beams as shown in FIG. 6A, while the 60 ° communication channel transceivers 43-1 to 43-M. In this case, the first three slots are assigned to the left beam, and the last three slots are assigned to the right beam. Hereinafter, the operation will be described.

When assigning a communication channel for outgoing / incoming calls or the like, the base station controller 26 uses the beam selection information detector 54
Is inquired about moving speed information (fading pitch Tf) and beam information. Based on the response, the base station controller 26 determines that the mobile station is moving at high speed if Tf is larger than a certain value, and allocates the transmitting / receiving apparatuses 37-1 to 37-L having a 120 ° beam communication channel. On the other hand, if Tf is smaller than a certain value, it is regarded as stationary or low-speed movement, and the transmitting / receiving apparatuses 43-1 to 43- having the 60 ° beam communication channel are considered.
Assign M. At this time, the 60 ° beam ports 34a, 3
4b, the direction of the mobile station is detected, and the right beam 28 or the left beam 27 is determined according to the information, and is assigned to the corresponding time slot.
The base station controller 26 operates the beam switch 58 in synchronization with the beam switching timing of the time slot. Since these transmitting / receiving apparatuses 43-1 to 43-M are assigned only to mobile stations determined to have a low moving speed, the probability that a channel switching operation will occur is low. Is not connected to the beam selection information detecting device 54.

It is possible to minimize the beam splitting loss by adaptively setting the ratio of the number of transmission / reception devices assigned to layers 1 and 2 according to the traffic and the moving speed distribution. In this embodiment, the transmission beam of layer 2 is 60 °, but the reception beam may be a 60 ° beam similarly to the transmission, or it may be received as a 120 ° beam after combining using a hybrid or the like. It is also possible. Since the transmission / reception apparatus of layer 2 can transmit with an antenna having a high gain, the transmission power is 3 dB lower than that of layer 1.

In the configuration shown in FIG. 5, similarly to the configuration shown in FIG. 4, the 120 ° beam antenna 33 is omitted, and the function of the 120 ° beam antenna is also used by two 60 ° beam antenna means. Can also. In the above description, the wide-angle beam is not limited to 120 °, but may be wider, for example, 360 °. Also, the service area covered by the wide-angle beam is not limited to the case where the narrow-angle beam covers two or more narrow-angle beams.

[0019]

As described above, according to the present invention, a narrow-angle beam antenna means can be allocated to a mobile station moving at a low speed, and it is unnecessary in a direction other than a direction in which a desired mobile station exists. Do not emit radio waves. As a result, the transmission power of the base station apparatus can be reduced, and furthermore, since the dispersion of radio waves can be suppressed, interference can also be reduced.

[Brief description of the drawings]

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

FIG. 2 shows time slots in the embodiment shown in FIG.
The figure which shows the example of the antenna directional characteristic at that time.

3A is a diagram illustrating an example of a procedure for determining a moving speed based on a fading pitch of a mobile station, and FIG. 3B is a diagram illustrating a relationship example between an antenna beam width (hierarchy) and transmission power.

FIG. 4 is a diagram showing an embodiment in which a diversity function is omitted from the embodiment shown in FIG. 1;

FIG. 5 is a diagram showing an embodiment in which a transmitting / receiving device for a narrow-angle beam communication channel is connected to a narrow-angle beam antenna means of a time slot allocated according to the direction of a mobile station.

FIG. 6 is a diagram showing a relationship example between a time slot and an antenna beam in the embodiment shown in FIG. 5;

FIG. 7 is a block diagram showing a conventional base station apparatus.

FIG. 8 is a diagram showing a relationship between a time slot and an antenna beam in a conventional base station apparatus.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification code FI Theme coat ゛ (Reference) H04B 17/00 H04B 17/00 M 7/26 B (72) Inventor Toshio Nojima 2-chome Nagatacho, Chiyoda-ku, Tokyo No. 11 F-term in NTT DOCOMO, INC. (Reference) 5J021 AA01 AA02 AA05 AA13 DB05 EA04 FA31 FA32 HA05 HA06 5K042 AA06 CA13 CA17 DA19 DA21 EA01 EA14 FA11 GA12 JA01 NA03 5K059 CC02 CC03 CC04 DD01 DD01 5K067 AA03 AA43 BB04 CC04 DD43 EE04 EE10 EE66 HH22 KK02 KK03

Claims (3)

[Claims] A first antenna unit having one wide-angle directional characteristic; and a plurality of second antenna units having a directional characteristic narrower than the wide-angle directional characteristic and substantially covering a transmission service area provided by the first antenna unit as a whole. Antenna means; a plurality of transmitting / receiving devices for wide-angle beam communication channels provided to be able to supply power to the first antenna means; and a plurality of narrow angles provided to be capable of supplying power to each of the second antenna means. A beam communication channel transmitting / receiving device; a beam selection information detecting device for detecting a moving speed of a mobile station and a direction of the narrow directional characteristic of the second antenna means; and the detected moving speed. And based on the direction of the mobile station,
A base station apparatus comprising: a base station controller that selectively assigns one of the wide-angle beam communication channel transmitting / receiving apparatus and the narrow-angle beam communication channel transmitting / receiving apparatus to the mobile station. 2. A plurality of first antenna means having one wide-angle directional characteristic, and a plurality of second antenna means having a directional characteristic narrower than the wide-angle directional characteristic and substantially covering a transmission service area of the first antenna means as a whole. Antenna means; a plurality of transmitting / receiving devices for wide-angle beam communication channels provided so as to be able to supply power to the first antenna means; and a plurality of transceivers provided so as to be selectively connectable to any of the second antenna means. A transmitting / receiving device for a narrow-angle beam communication channel; a beam selection information detecting device for detecting a moving speed of a mobile station and a direction of the narrow directional characteristic of the second antenna means; Based on the moving speed and the direction of the mobile station,
The mobile station is provided with one of the wide-angle beam communication channel transceivers or one of the narrow-angle beam communication channel transceivers.
And a base station controller for controlling switching connection between the narrow-angle beam communication channel transmitting / receiving apparatus and the second antenna means according to the allocated time slot. 3. The first antenna means and a plurality of the second antenna means.
3. The base station apparatus according to claim 1, wherein the base station apparatus is also used as an antenna.