KR100290768B1 - Base station coverage controller - Google Patents

Abstract

The present invention relates to a mobile communication system, and an object thereof is to provide a base station coverage control apparatus capable of controlling base station coverage in real time and automatically using location information of a terminal in a mobile communication system. In the base station coverage control apparatus, the multibeam antenna generates a plurality of beams. The beam controller applies a plurality of variable input powers to the multibeam antenna and switches base station signals from the base station transmitter to adjust the size and number of the plurality of beams generated by the multibeam antenna. The antenna controller controls the operation of the beam controller and generates a control signal according to the state of the plurality of beams. The coverage controller displays the base station coverage map and the terminal distribution map based on the terminal location information and the base station identification number received from the terminal, and generates a control signal of the antenna controller based on the base station coverage map and the terminal distribution map. According to the present invention, it is possible to more precisely and efficiently optimize the wireless network related to the handoff area, and at the same time, distribute the traffic concentrated in one base station to adjacent base stations, thereby increasing the overall system capacity.

Description

Base station coverage control device {BASE STATION COVERAGE CONTROLLER}

The present invention relates to a mobile communication system, and more particularly, to an apparatus for controlling the coverage of a base station in real time and automatically in a mobile communication system.

1 shows a conventional base station transmitter. The output of each of the high power amplifiers 102a, 102b, 102c, 102d of the high power amplifier module 102 of the final stage is synthesized by the synthesizer 104 and then propagated into the space through the band pass filter 106 and the antenna 108. do.

2 and 3 illustrate a method of configuring spatial diversity of a conventional base station. In the conventional method of configuring spatial diversity of a base station, as shown in FIG. 2, a duplexer 206 is used to transmit and receive to one antenna 202 and another receive-only antenna 204, and FIG. 3. As shown, there is a method of transmitting with one antenna 302 and using two separate receiving antennas 306.

In general, the coverage of the base station is determined by the transmission power of the base station, the radiation pattern of the antenna, and the propagation environment. Since the propagation environment is determined when the installation location of the base station antenna is determined, mainly the transmission power of the base station and the radiation pattern of the antenna are the main factors for determining coverage. It is important that base station coverage be designed as large as possible to ensure that the radio shadow area is minimized. However, because the base station has a limited radio channel capacity, for overall network operation efficiency, the handoff area with the neighboring base station should not be duplicated or the specific base station should not be congested with traffic.

In the region between neighboring base stations, there is a hand off area in which two or more base station signals exist. Handoff is necessary to ensure that the call is continuous without disconnection even if the mobile station moves to another base station coverage area while making a call. In order to be an efficient wireless network, an appropriate size handoff area must exist. In the CDMA mobile communication, the mobile station simultaneously communicates with two or more base stations when the mobile station is being handed off, thus occupying more radio channels than when the mobile station is not handed off. As a result, the number of users that the base station can serve at the same time, that is, the capacity is reduced, and the larger the handoff area, the larger the phenomenon. On the other hand, if the handoff area is too narrow, the call may be dropped during the move, so the handoff area should be designed to have an appropriate size.

In addition to the size of the area in relation to the handoff, the number of base stations received in the handoff area is important. This is especially important in a CDMA mobile communication system where all base stations use the same frequency. In a CDMA system, base station signals other than one base station signal required for communication act as all interference signals, which causes a deterioration in communication quality. Therefore, as more base station signals other than the base station required for handoff are received in the handoff area, communication quality of the area is degraded. Such an area where a lot of unnecessary base station signals are received is called a pilot polling area.

In order to solve the problems related to the handoff and to efficiently operate the network, wireless network optimization is performed. The methods include adjusting the tilt angle of the antenna and adjusting the transmission power.

4A to 4D show examples of directional antenna radiation patterns of a conventional base station. 4A shows that the number of main beams 402 is one and the horizontal beam width is 30 degrees. 4B shows that the number of main beams 404 is one and the horizontal beam width is 45 degrees. 4C shows that the number of main beams 406 is one and the horizontal beam width is 60 degrees. 4D shows that the number of main beams 402 is one and the horizontal beam width is 90 degrees. However, the problem related to the handoff does not occur in the same manner in all boundary regions of one base station coverage but has different characteristics for each region. In other words, one area may be too large in handoff area, the other area may be small, and the pilot solution area may occur only locally. In order to solve this problem, the adjustment of the transmission power affects the transmission power in all directions, and thus, there is a disadvantage in that it is impossible to control the transmission power in the specific direction in which the problem occurs. The effect is great, but it is difficult to control in other directions.

The maximum number of radio channels that can be used at a base station is determined. Sometimes, the traffic is concentrated in one base station, and thus the subscribers who want to communicate with each other may not be able to communicate because all the wireless channels are used. In order to solve such a situation, a method such as an expansion of a wireless channel or an expansion of a base station should be used, but this method has a disadvantage in that it is expensive compared with not having much time for concentrating traffic.

Accordingly, an object of the present invention is to provide a base station coverage control apparatus capable of controlling base station coverage in real time and automatically using location information of a terminal in a mobile communication system.

The present invention to achieve the above object is a multi-beam antenna for generating a plurality of beams; A beam controller for applying a plurality of variable input powers to the multibeam antenna and switching a base station signal from a base station transmitter to adjust the size and number of the plurality of beams generated by the multibeam antenna; An antenna controller for controlling an operation of the beam controller and generating a control signal according to the state of the plurality of beams; And a coverage controller displaying a base station coverage map and a terminal distribution map based on the terminal location information and the base station identification number received from the terminal, and generating a control signal of the antenna controller based on the base station coverage map and the terminal distribution map. It provides a base station coverage control device, characterized in that.

The coverage controller analyzes the terminal location information signal and the base station identification number from the terminal to display a base station coverage map and a terminal distribution map and a base station coverage map and a terminal distribution map displayed by the base station coverage display. It is preferable to include an antenna automatic control unit for generating an off-region size, a pilot number of pilot-pollution regions, and an antenna control signal for adjusting traffic variance.

1 is a block diagram showing a conventional base station transmitter.

2 and 3 are spatial diversity diagrams used in a conventional base station.

4A to 4D are diagrams showing examples of conventional base station antenna radiation characteristics.

5 is a configuration diagram of a mobile communication system including a base station control apparatus according to a preferred embodiment of the present invention.

6 is a block diagram illustrating an example of a base station illustrated in FIG. 5.

7A to 7D are diagrams illustrating various radiation characteristics of the multiple beams generated by the control of the beam controller shown in FIG. 6.

8A to 8D are diagrams showing examples of a configuration method of the diversity synthesizer shown in FIG. 6.

9 is a block diagram illustrating another example of the base station illustrated in FIG. 5.

<Description of the code | symbol about the principal part of drawing>

502: terminal with GPS receiver 504: base station

508: base station controller 510: switchboard

512: coverage controller 514: coverage display unit

516: automatic antenna control unit 602,902: multi-beam antenna

604, 904: beam controller 606, 906: antenna controller

608: Divider 610,912: Diversity Synthesizer

612,914 duplexer 908 high-power amplifier

910: band pass filter 602a, 902a: antenna element

602b and 902b multi-beam forming circuits 604a and 904a variable attenuators

604b, 904b: switch

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

5 illustrates a mobile communication system having a base station coverage control apparatus according to a preferred embodiment of the present invention. The base station coverage control apparatus according to the present invention includes a base station 504 and a coverage controller 512.

The GPS receiver embedded terminal 502 receives a GPS signal from a GPS satellite (not shown) and periodically transmits its location information to the base station 504 during communication. The base station 504 transmits the position information of the GPS receiver embedded terminal 502 to the base station controller 508 and the exchange 510 through the T1 or E1 transmission path 506.

6 illustrates an example of the base station 504 shown in FIG. 5.

The base station 504 includes a multibeam antenna 602, a beam controller 604, an antenna controller 606, a divider 608, a diversity synthesizer 610, and a plurality of duplexers 612. Multibeam antenna 602 generates multiple beams. The multibeam antenna 602 includes four antenna elements 602a and a multibeam forming circuit 602b. The four antenna elements 602a are arranged in a horizontal direction or in a circle. The multibeam forming circuit 602b is connected to the four antenna elements 602a to produce four beams. The multi-beam antenna 602 is two or more antennas of the main beam, the present invention will be described by taking an antenna having four beams as an example.

The beam controller 604 applies a plurality of variable input powers to the multi-beam antenna 602 to adjust the size and number of the plurality of beams generated by the multi-beam antenna 602 and the base station from the base station transmitting end. Switch the signal. The beam control unit 604 includes four variable attenuators 604a and four switches 604b. The four variable attenuators 604a apply variable input power to the multibeam antenna 602 to adjust the size of the beam of four generated by the multibeam antenna 602, respectively. Four switches 604b are controlled in an on / off state under the control of the antenna controller 606 to control the number of beams of the multibeam antenna 602 to switch the base station signal BS from the base station transmitter.

7A to 7D show various radiation characteristics of the multiple beams generated by the control of the beam control unit 604 shown in FIG. 6. 7A shows that all four switches 604b of the beam control unit 604 are turned on so that all four beams 702 generated by the multibeam antenna 602 are transmitted and four variable attenuators 604a. By means of which the size of the four beams to be transmitted is adjusted equally. FIG. 7B shows that all four switches 604b of the beam control unit 604 are turned on so that the four beams generated by the multibeam antenna 602 are transmitted and the four variable attenuators 604a are used. The size of three beams 704 of the four beams transmitted is the same and indicates that the remaining one beam 706 is adjusted smaller than the three beams 704.

FIG. 7C shows that three of the four switches 604b of the beam control unit 604 are on and one is off so that three of the four beams generated by the multibeam antenna 602 are transmitted. And among the three beams transmitted by the three variable attenuators corresponding to the three switches in the on state of the four variable attenuators 604a, the two beams 708 are the same size and the other one beam 710 is the same. This is controlled to be smaller than the two beams 708. FIG. 7D shows two of the four beams 712 generated by the multibeam antenna 602 with two of the four switches 604b of the beam control unit 604 turned on and the other two off. ) Is transmitted and the size of the two beams transmitted is equally adjusted by the two variable attenuators corresponding to the two switches in the on state of the four variable attenuators 604c.

The antenna controller 606 controls the operation of the beam control unit 604 and generates a control signal SC according to the state of the plurality of beams generated by the multibeam antenna 602. The distributor 608 distributes the base station signal BS from the base station transmitting end by the number of beams generated by the multibeam antenna 602.

The diversity synthesizer 610 is configured to generate four terminal signals received from the multibeam antenna 602, that is, a first terminal signal FM, a second terminal signal SM, a third terminal signal TM, and a fourth terminal signal HM. In response to the control signal SC according to the state of the beam generated by the controller 606, it converts into two received signals required for diversity, namely, a first received signal FR and a second received signal SR.

8A to 8D show examples of a configuration method of the diversity synthesizer 610 shown in FIG. 6. Referring to FIG. 8A, the diversity synthesizer 610 includes four terminal signals received from the multibeam antenna 602, namely, a first terminal signal FM, a second terminal signal SM, a third terminal signal TM, and a fourth terminal signal. Receive the terminal signal HM. The diversity synthesizer 610 synthesizes the first terminal signal FM and the second terminal signal SM and converts it into a first received signal FR, and synthesizes a third terminal signal TM and a fourth terminal signal HM to receive a second received signal. Convert to SR. Referring to FIG. 8B, the diversity synthesizer 610 may include four terminal signals received from the multibeam antenna 602, namely, a first terminal signal FM, a second terminal signal SM, a third terminal signal TM, and a fourth terminal signal. Receive the terminal signal HM. The diversity synthesizer 610 synthesizes the first terminal signal FM and the third terminal signal TM, converts it into a first received signal FR, and synthesizes a second terminal signal SM and a fourth terminal signal HM to receive a second received signal. Convert to SR.

Referring to FIG. 8C, the diversity synthesizer 610 may include four terminal signals received from the multibeam antenna 602, namely, a first terminal signal FM, a second terminal signal SM, a third terminal signal TM, and a fourth terminal signal. Receive the terminal signal HM. The diversity synthesizer 610 converts the second terminal signal SM into a first received signal FR and converts a third terminal signal TM into a second received signal SR. Referring to FIG. 8D, the diversity synthesizer 610 may include four terminal signals received from the multibeam antenna 602, namely, a first terminal signal FM, a second terminal signal SM, a third terminal signal TM, and a fourth terminal signal. Receive the terminal signal HM. The diversity synthesizer 610 converts the second terminal signal SM into a first received signal FR, and synthesizes a third terminal signal TM and a fourth terminal signal HM into a second received signal SR.

Multiple duplexers 612 couple one of the divider 608 and diversity synthesizer 610 to the multibeam antenna 602 via the beam control 604. The exchange 510 transmits to the coverage controller 512 together with the terminal location information signal PI indicating the location information of the GPS receiver embedded terminal 502 and the base station identification number BID.

The coverage controller 512 displays the base station coverage map and the terminal distribution map based on the terminal location information PI and the base station identification number BID received from the exchange 510. The coverage controller 512 also generates a control signal of the antenna controller 606 based on the base station coverage map and the terminal distribution map. The coverage controller 512 includes a coverage indicator 514 and an automatic antenna controller 516.

The coverage display unit 514 analyzes the terminal location information PI and the base station identification number BID received from the exchange 510 and displays it on a map. That is, when the location information is accumulated and displayed on the map for a long time, the base station coverage map can be obtained. The coverage display unit 514 may also display the terminal location information PI and the base station identification number BID on a map in real time to obtain a geographical distribution map of the GPS embedded terminal 502 currently being serviced by the base station. When the GPS embedded terminal 502 is performing handoff, since the location information is simultaneously transmitted to two or more base stations, the GPS embedded terminal 502 may display the handoff area and the number of base stations or pilots received at this time. 516 analyzes the base station coverage map and the terminal distribution map displayed by the base station coverage display unit 514 to generate a handoff area size, a pilot number of pilot pollution area, and antenna control signals HC and TC for traffic distribution adjustment.

Hereinafter, the operation of the base station coverage control apparatus according to a preferred embodiment of the present invention will be described with reference to the accompanying drawings.

The GPS receiver embedded terminal 502 receives a GPS signal from a GPS satellite (not shown) and periodically transmits its location information to the base station 504 during communication. The base station 504 transmits the position information of the GPS receiver embedded terminal 502 to the base station controller 508 and the exchange 510 through the T1 or E1 transmission path 506.

In this case, the operation of the base station 504 will be described with reference to FIG. 6.

Multibeam antenna 602 generates four beams. Four variable attenuators 604a of the beam controller 604 adjust the size of the beam of four generated by the multibeam antenna 602, respectively. The switch 604b is controlled on / off by the antenna controller 606 to adjust the number of beams of the multibeam antenna 602 to switch the base station signal BS from the base station transmitting end. The distributor 608 distributes the base station signal BS from the base station transmitting end by the number of beams generated by the multibeam antenna 602.

Diversity synthesizer 610 transmits four terminal signals received from the multibeam antenna 602, namely, a first terminal signal FM, a second terminal signal SM, a third terminal signal TM, and a fourth terminal signal FM. In response to the control signal SC according to the state of the beam generated by the controller 606, it converts into two received signals required for diversity, namely, a first received signal FR and a second received signal SR. In this case, since the diversity scheme uses beams facing different directions, it is called beam diversity or angular diversity. The signal synthesis method of the diversity synthesizer has various methods according to the radiation characteristics of the multi-beam antenna, that is, the control values of each variable attenuator and each switch and the propagation environment of the radio section. The exchange 510 transmits to the coverage controller 512 together with the terminal location information signal PI indicating the location information of the GPS receiver embedded terminal 502 and the base station identification number BID.

The coverage display unit 514 of the coverage controller 512 analyzes and displays the terminal location information PI and the base station identification number BID received from the exchange 510 on the map. That is, when the location information is accumulated and displayed on the map for a long time, the base station coverage map can be obtained. The coverage display unit 514 may also display the terminal location information PI and the base station identification number BID on a map in real time to obtain a geographical distribution map of the GPS embedded terminal 502 currently being serviced by the base station. When the GPS embedded terminal 502 is performing handoff, since the location information is simultaneously transmitted to two or more base stations, the GPS embedded terminal 502 may display the handoff area and the number of base stations or pilots received at this time. The automatic antenna control unit 516 analyzes the base station coverage map displayed by the base station coverage display unit 514 to generate an antenna control signal HC for adjusting the handoff area size and the pilot number of the pilot pollution area. The automatic antenna controller 516 analyzes the terminal distribution map displayed by the base station coverage display unit 514 to generate an antenna control signal TC for controlling traffic variance.

The antenna control signal HC for adjusting the number of pilots in the handoff area size and the pilot convolution area and the antenna control signal TC for controlling traffic distribution are transmitted to the antenna controller 606 through a public switched telephone network (PSTN) 518. .

The antenna controller 606 is responsive to the antenna control signal HC for adjusting the handoff area size and the pilot number of the pilot convolutional area from the antenna automatic control unit 516 of the coverage controller 512 and the antenna control signal TC for controlling traffic variance. The beam controller control signal BC is generated to control the operation of the beam controller 604. The antenna controller 606 generates a control signal SC according to the state of the plurality of beams generated by the multibeam antenna 602.

9 shows another example of the base station shown in FIG. 5.

The base station includes a multibeam antenna 902, beam control 904, antenna controller 906, four high power amplifiers 908, four band pass filters 910, diversity synthesizer 912, and four duplexers. 914. The multibeam antenna 902 generates multiple beams. The multibeam antenna 902 includes four antenna elements 902a and a multibeam forming circuit 902b. The four antenna elements 902a are arranged in a horizontal direction or a circle. The multibeam forming circuit 902b is connected to the four antenna elements 902a to produce four beams. The multi-beam antenna 902 is two or more antennas of the main beam, the present invention will be described by taking an antenna having four beams as an example.

The beam controller 904 outputs variable input power to adjust the size and number of the plurality of beams generated by the multibeam antenna 902, and outputs four base station signals BS1, BS2, BS3, and Switch BS4. The beam control unit 904 includes four variable attenuators 904a and four switches 904b. The four variable attenuators 904a output four variable input powers to adjust the size of the four beams generated by the multibeam antenna 902, respectively. The four switches 904b are controlled in an on / off state under the control of the antenna controller 906 to adjust the number of beams of the multibeam antenna 902, so that the four base station signals BS1, BS2 from the base station transmitter end. Switches BS3 and BS4.

The antenna controller 906 controls the operation of the beam control unit 904 and generates a control signal SC according to the state of the plurality of beams generated by the multibeam antenna 902. Four high output amplifiers 908 amplify each of the four variable input powers from the beam control 904. Four band pass filters 910 band pass filter each of the outputs of the four high power amplifiers 908. Diversity synthesizer 912 controls the four terminal signals FM, SM, TM, and HM received via the multibeam antenna 902 according to the state of the beam generated by the antenna controller 906. In response, it converts the two received signals FR and SR required for diversity. Four duplexers 914 selectively couple one of the four high power amplifiers 908 and diversity synthesizer 912 to the multibeam antenna 902.

As described above, the terminal periodically transmits the position information transmitted during communication with the base station to the base station controller and the exchange through the transmission path, and the exchange extracts the position information and delivers the position information to the coverage automatic controller. The automatic coverage controller creates a base station coverage map and a terminal distribution map, and performs an antenna control algorithm to generate antenna control signals and transmit them to the antenna controller. The antenna controller controls the input power of each of the multibeam antennas and radiates them. By controlling the pattern, it is possible to more precisely and efficiently optimize the wireless network related to the handoff area, and to increase the overall system capacity by distributing the traffic concentrated in one base station to adjacent base stations.

Claims (6)

A multibeam antenna for generating a plurality of beams; A beam controller for applying a plurality of variable input powers to the multibeam antenna and switching a base station signal from a base station transmitter to adjust the size and number of the plurality of beams generated by the multibeam antenna; An antenna controller for controlling an operation of the beam controller and generating a control signal according to the state of the plurality of beams; And And a coverage controller configured to display a base station coverage map and a terminal distribution map based on the terminal location information and the base station identification number received from the terminal, and generate a control signal of the antenna controller based on the base station coverage map and the terminal distribution map. Base station coverage control device, characterized in that. 2. The base station coverage control apparatus of claim 1, wherein the multibeam antenna comprises four antenna elements arranged horizontally and a multibeam forming circuit connected to the four antenna elements to generate four beams. The multi-beam antenna of claim 1, wherein the multi-beam antenna generates four beams, and the beam controller generates four variable input powers to adjust the size of the four beams generated by the multi-beam antenna, respectively. Four variable attenuators applied to the antenna and four switches for controlling the on / off state under the control of the antenna controller to control the number of beams of the multi-beam antenna to switch the base station signal from the base station transmitting end Base station coverage control device, characterized in that. The base station coverage map unit of claim 1, wherein the coverage controller analyzes a terminal location information signal and a base station identification number from the terminal to display a base station coverage map and a terminal distribution map. And an antenna automatic control unit for generating a handoff area size, a pilot number of a pilot pollution area, and an antenna control signal for adjusting traffic distribution by analyzing a terminal distribution map. 2. The apparatus of claim 1, further comprising: a divider for distributing a base station signal from a base station transmitter by the number of beams generated by the multibeam antenna; A diversity synthesizer for converting four terminal signals received from the multibeam antenna into two received signals required for diversity in response to a control signal according to the state of the beam generated by the antenna controller; And And four duplexers for selectively coupling one of the divider and diversity synthesizer to the multibeam antenna. 4. The apparatus of claim 1, further comprising: four high output amplifiers each amplifying the plurality of variable input powers from the beam controller; Four band pass filters for band pass filtering the outputs of the four high power amplifiers, respectively; A diversity synthesizer for converting four terminal signals received from the multibeam antenna into two received signals required for diversity in response to a control signal according to the state of the beam generated by the antenna controller; And And four duplexers for selectively coupling one of the four high power amplifiers and the diversity synthesizer to the multibeam antenna.