JP2010263450A - Communication system, base station, cell radius setting method thereof and program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To shorten the time required, when adjusting a cell radius such that a base station covers a terminal that does not belong to a different cell. <P>SOLUTION: The communication system includes a plurality of cells 11, 12 and 14(a, b and c), a plurality of base stations 21 to 24 for making the cells 11 to 14(a, b, and c) a cover area, and a plurality of terminals 31 to 35 for communicating with the respective base stations 21 to 24. The base station 24 has a terminal communicating section and a position information acquiring section for notifying the number of base stations, with which the terminals 31 to 35 existing around the base station 24 can communicate and receiving notification of position information of the terminal 31 to 35. Furthermore, the base station 24 has a cell radius control section for determining a cell radium, on the basis of distance information between the terminals 31 to 35 which do not have any other communicable base stations and the base station 24, which is calculated from the notified information and the position information of the base station 24. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a communication system, a base station, a cell radius setting method thereof, and a program.

  At present, it is not uncommon for a mobile phone to have a gap in a cell that can be used in a call area and to make a call. For this reason, there are many calls for a device that allows mobile users to easily make calls even in areas where calls are not possible.

  In order to meet such demands, studies have been conducted on a micro base station (Home BTS: Home Base Transceiver Station). The micro base station is a micro base station that can be carried by a base transceiver station (BTS: Base Transceiver Station) for home use and consumer use, and is expected to be widely used in the future with the spread of terminals. .

  Usually, base stations are installed so that callable ranges (cells) overlap with each other, and a terminal has information on a plurality of base stations with which communication is possible.

  When installing and updating a micro base station, the required cell radius varies depending on the installation location. If the cell radius is expanded to a place where it can be updated by an existing base station, transmission power is wasted and the possibility that a line other than the original user will be used increases. On the other hand, if the cell radius is too narrow, there is a problem that there are places where calls cannot be made, which is inconvenient.

  Thus, there is a problem that it is difficult to set the cell radius of the ultra-small base station to the minimum necessary. Accordingly, an invention for automatically setting the cell radius of a base station or a micro base station has been proposed.

Patent Document 1 discloses a transmission power control apparatus that determines transmission power based on a relative distance between a base station and a mobile device when a mobile device enters an adjacent cell. This is an initial transmission in which when a mobile device advances from one zone and enters another zone, the distance between the base station and the mobile device is measured and the base station device transmits to the mobile device according to the information related to the distance. The power is set.
In Patent Document 2, a small base that can autonomously assign a spreading code so as to avoid interference with surrounding cells based on the position information of base stations existing in the vicinity and the position information of small base station devices A station apparatus, a base station registration management system, a registration method, a registration management method, and a program are disclosed.
Patent Document 3 discloses a communication system, a base station, a cell radius setting method, and a program capable of reducing the cell range until a terminal exists only in the cell. In the base station, first, the cell radius is set to the maximum, and the terminals existing around the base station are notified of the number of existing base stations that can communicate. Next, when there is a terminal that can communicate with a plurality of existing base stations, the cell radius is reduced and the number of existing base stations that can communicate with the terminal is notified. In this way, by repeating the change of the cell radius of the base station and the reception of the number of base stations with which the terminal can communicate, the cell radius is decreased until there is no terminal that can communicate with the existing base station. Is to determine.

JP 2005-203866 A JP 2007-266785 A JP 2008-109322 A

  As described above, Patent Literature 3 can adjust the cell radius so as to cover terminals that do not belong to other cells. However, in the cell radius determination procedure (transmission power determination procedure) disclosed in Patent Document 3, it is necessary for the base station to repeatedly receive notifications from the terminal while gradually decreasing the cell radius from the state in which the cell radius is maximized. There is. For this reason, there is a problem that it takes a long time for the base station to determine the cell radius.

  Note that Patent Document 1 does not adjust the cell radius so as to cover a terminal that does not belong to another cell, and does not disclose the above-described problem and a technique for solving it. Patent Document 2 also does not disclose the above-described problem and a method for solving it.

  The present invention has been made based on the above-described knowledge, and provides a base station and a communication system that can shorten the time required to adjust the cell radius so as to cover terminals that do not belong to other cells. For the purpose.

  A communication system according to a first aspect of the present invention is a communication system including a plurality of cells, a plurality of base stations that cover each cell, and a plurality of terminals that communicate with each base station. . At least one of the plurality of base stations includes an information collection unit that receives a notification of the number of base stations that can be communicated by terminals existing around the base station and a notification of the location information of the terminal, and the information collection unit Cell radius control means for determining the cell radius based on the distance information between the base station and the terminal whose number of other base stations capable of communication is zero, calculated from the obtained information and the position information of the base station .

  Further, the base station according to the second aspect of the present invention includes an information collection unit that receives a notification of the number of base stations that can be communicated by terminals existing around the base station and a notification of the location information of the terminal, and the information collection Cell radius control for determining the cell radius based on the distance information between the base station and the terminal whose number of other base stations capable of communication is zero, which is calculated from the information obtained by the means and the position information of the base station Means.

  A cell radius setting method according to the third aspect of the present invention is a cell radius setting method for a base station. The method comprises steps (a) and (b). (A) acquiring the number of base stations and terminal position information that can be communicated from terminals existing around the base station and acquiring terminal position information; (b) the acquired information and the target base station; The cell radius is determined on the basis of the distance information between the target base station and the terminal whose number of other base stations capable of communication is zero, which is calculated from the position information.

  A cell radius setting program according to the fourth aspect of the present invention is a program that causes a computer to execute cell radius setting of a base station. The program includes steps (c) and (d). (C) acquiring the number of base stations that can be communicated by terminals existing around the base station and the position information of the terminals; (d) calculated from the acquired information and the position information of the target base station; A cell radius is determined based on distance information between a terminal whose number of other base stations capable of communication is zero and a target base station.

According to each aspect of the present invention described above, it is possible to provide a base station and a communication system that can shorten the time required to adjust the cell radius so as to cover terminals that do not belong to other cells.

It is a schematic diagram of the communication system concerning Embodiment 1 of invention. It is a block diagram of the base station concerning Embodiment 1 of invention. It is a block diagram of the terminal concerning Embodiment 1 of invention. It is a flowchart which shows an example of the flow of the process concerning Embodiment 1 of invention. It is a block diagram of the base station concerning Embodiment 2 of invention. It is a flowchart which shows an example of the flow of a process of the cell radius setting method concerning Embodiment 2 of invention.

Embodiment 1 of the Invention
Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.
FIG. 1 is a configuration diagram of a communication system according to the present embodiment. It is assumed that the base station 24 is newly installed outside the range of each cell radius of the existing base stations 21 to 23.

  In FIG. 1, the case where the radius of the cell 14 is maximum is indicated by 14a. All of the terminals 31 to 35 exist in the cell radius 14a.

  The base station 24 receives a notification of the number of base stations that can be communicated with the terminals existing around the base station and a notification of the position information of the terminal, and receives other information that can be communicated from the information by the notification and the position information of the base station. The distance between the terminal whose number of base stations is zero and its own base station is calculated, and the cell radius is determined based on this distance. Since the position information is included, it is not necessary to repeatedly confirm the notification from the terminal while gradually reducing the cell radius, and the processing time for setting the cell radius can be shortened.

  If there is only one terminal that does not belong to another cell, the cell radius may be determined so as to cover the position of this terminal. When there are a plurality of other terminals, the cell radius may be determined so as to cover the farthest terminal position among the plurality of terminals. Further, the cell radius may be determined so as to cover the nearest terminal position among the plurality of terminals. Further, the cell radius may be determined so as to cover up to a predetermined number of terminals counted from the near side among the plurality of terminals. Further, the cell radius may be determined so as to cover up to the average position of the plurality of terminals.

  In addition, the position information system 1 should just be what can confirm position information, and can be used as GPS (Global positioning system).

  FIG. 2 shows a configuration example of the base station 24 according to the first embodiment of the invention. The base station 24 includes a cell radius control unit 50, a terminal communication unit 51, and a location information acquisition unit 52. The cell radius control unit 50 includes a terminal location information determination unit 53, a received BTS number determination unit 55, and a cell setting unit 56.

  The terminal communication unit 51 communicates with terminals 31 to 35 existing around the base station 24 and receives notification of the number of base stations with which the terminals 31 to 35 can communicate and position information.

  The location information acquisition unit 52 communicates with the location information system 1 and receives a notification of the location of the base station 24.

  The terminal location information determination unit 53 determines whether the base station 24 and the terminals 31 to 35 are based on the location information of the terminals 31 to 35 received by the terminal communication unit 51 and the location information of the base station 24 received by the location information acquisition unit 53. The relative positional relationship is determined.

  Based on the method set by the BTS mode setting unit 54, the received BTS number determining unit 55 determines the number of base stations communicable with the terminals 31 to 35 received by the terminal receiving unit 51 and the terminal location information determining unit 53. The number of base stations with which the terminals 31 to 35 can communicate is determined based on the positional information of the base station 24 and the terminals 31 to 35.

  The cell setting unit 56 sets the cell radius 14 based on the determination result of the received BTS number determination unit 55.

  FIG. 3 shows a configuration example of the terminals 31 to 35 according to the present invention. Each of the terminals 31 to 35 includes a BTS communication unit 61, a position information acquisition unit 62, a BTS number determination unit 63, and a BTS data transmission unit 64.

  The BTS communication unit 61 communicates with the existing base stations 21 to 23.

  The position information acquisition unit 62 communicates with the position information system 1 and acquires the position information of the terminals 31 to 35.

  The BTS number determination unit 63 determines the number of base stations with which the BTS communication unit 61 can communicate.

  The BTS data transmission unit 64 transmits the position information acquired by the position information acquisition unit 62 and the number of base stations determined by the BTS number determination unit 63 to the base station 24.

  Next, the operation of the communication system according to the present embodiment will be described. FIG. 4 is a flowchart showing the operation of the first embodiment. As a premise, it is assumed that terminals 31 to 35 exist in the cells 11 to 14 as shown in FIG. In this case, the distance between the terminal 31 and the base station 24 is a1, the distance between the terminal 32 and the base station 24 is a2, the distance between the terminal 33 and the base station 24 is a3, the distance between the terminal 34 and the base station 24 is a4, The distance between the terminal 35 and the base station 24 is a5, and the distance relationship is a5> a1> a4> a2> a3.

  A base station 24 is newly installed at a position not covered by the cell 11 covered by the existing base station 21, the cell 12 covered by the base station 22, and the cell 13 covered by the base station 23, and power is supplied to the base station 24. Is input (step S1).

  Next, the base station 24 acquires the position information of the base station 24 through the position information acquisition unit 52 by the position information system 1 (step S2).

  Next, the base station 24 sets the radius of the cell 14 to the maximum (step S3). In this case, the range of the cell 14 is 14a (see FIG. 1).

Next, the base station 24 receives notification of the number of existing base stations that can communicate and the location information of the terminals from the terminals 31 to 35 existing in the vicinity (step S4).
The notification includes the number of base stations that can be communicated with the location information obtained by the operations of the BTS communication unit 61, the BTS number determination unit 62, and the location information acquisition unit 63 from the BTS data transmission unit 64 to the base station. 24. The base station 24 receives the notification through the terminal communication unit 51.

  In the initial state, the numbers of base stations notified from the terminals 31 to 35 are terminal 31 = 1, terminal 32 = 1, terminal 33 = 2, terminal 34 = 3, and terminal 35 = 2.

  The base station 24 sets the cell radius based on the information notified from the terminals 31 to 35 and the position information of the base station 24 (step S5). Here, in the invention disclosed in Patent Document 3, it is necessary to confirm the number of base stations with which each terminal can communicate by receiving notifications from the terminals 31 to 35 a plurality of times. The station 24 has information on the number of base stations and positions that the terminals 31 to 35 can communicate with, and it is not necessary to confirm the notification from the terminals a plurality of times, and the processing time can be shortened.

Note that the present invention is not limited to the above-described embodiment, and can be changed as appropriate without departing from the spirit of the present invention. For example, the base station 24 can be a micro base station. Further, the notification of the number of base stations to which the surrounding terminals belong and the notification of position information (step S3) are not directly notified from the terminals 31 to 35 to the base station 24, but these information is received from the terminals 31 to 35. Notification may be made to the existing base stations 21 to 23 or a separately prepared server, and the existing base stations 21 to 23 or the server may notify the base station 24.
Also, acquisition of position information (step S2), notification of the number of base stations with which peripheral terminals can communicate and notification of position information of peripheral terminals after setting the cell radius to the maximum (steps S3 and S4) The execution order of can be changed as appropriate.

Embodiment 2 of the Invention
In this embodiment, when determining the cell radius based on the notification from the terminal about the number of base stations to which the terminal belongs and the distance between the terminal and the base station, the terminal from the base station closest to the base station Low Power mode that determines a cell radius by determining a terminal that can communicate with another base station, and a cell radius that determines a terminal that cannot communicate with another base station in order from a terminal that is far from the base station. This relates to the HighPower mode for setting the.

FIG. 1 shows 14b when the radius of the cell 14 is the minimum radius determined in the HighPower mode described later, and 14c indicates the case where the radius of the cell 14 is the minimum radius determined in the LowPower mode described later. . All of the terminals 31 to 34 exist in the cell radius 14b, and the terminal 32 and the terminal 33 exist in the cell radius 14c.
FIG. 5 shows a configuration diagram of the base station shown in FIG. 2 with a BTS mode setting unit 54 added. The BTS mode setting unit 54 sets whether to determine the number of base stations that can be received by the terminals 31 to 35 by either the HighPower mode or the LowPower mode described later.

  Thereby, in step S5 of FIG. 4, the procedure until the cell radius is set can be selected from the information notified from the terminals 31 to 35 and the position information of the base station 24.

FIG. 6 is a flowchart showing details of the process in step S5 of FIG.
First, the BTS mode setting unit 54 sets a mode. For example, it is possible to set a LowPower mode for the purpose of operating in a minimum cell range and reducing the power, or a HighPower mode for the purpose of covering a wide range (step S51).

  When the Low Power mode is selected, the base station 24 determines the position information of the terminals 31 to 35 by the terminal position information determination unit 53, and receives the number of received BTSs from the terminal having a short relative distance to the base station 24. The number of base stations that can communicate with each other is confirmed (step S52).

  In step S53, first, the base station 24 extracts terminals whose number of base stations with which communication is possible is one. When the terminals 31 to 35 exist in the arrangement shown in FIG. 1, the determination is first started from the terminal 33 having the shortest distance from the base station 24. The number of base stations that can be communicated with the terminal 33 determined here is 2 and the number of base stations is not 1. Therefore, the terminal closest to the base station 24 after the terminal 33 is determined. By repeating this process, the terminal 32 having the shortest distance from the base station 24 is extracted from the terminals having the number of base stations that can communicate with each other. Next, the number of base stations that can communicate with the terminal 34 closest to the base station 24 next to the extracted terminal 32 is confirmed.

  If the number of base stations that can be communicated with the terminal closest to the base station 24 next to the terminal with the extracted number of base stations that can communicate with is 1, the process returns to step S53, and the extracted base stations with which communication is possible Similar processing is repeated for the terminal closest to the base station 24 next to the terminal whose number is one. ("No" in step S54).

If the number of base stations that can communicate with a terminal next to the base station 24 next to the terminal with the number of base stations that can communicate with is 2 or more (“Yes” in step S54), the number of base stations that can communicate with is 1 The cell setting unit 56 sets the distance to the terminal to the cell radius (step S55), and starts communication as a base station.
In the example of the arrangement shown in FIG. 1, since the number of base stations with which the terminal 34 can communicate is 3, a3, which is the distance between the terminal 32 and the base station 24, is set as the cell radius, and the cell radius is 14c (see FIG. 1). 1).

  When the high power mode is selected in step S51, the base station 24 determines the position information of the terminals 31 to 35 by the terminal position information determination unit 53, and receives the number of received BTSs from the terminal having a relative distance from the base station 24. The determination unit 55 determines the number of base stations that can communicate (step S56).

  In step S57, first, the base station 24 extracts terminals whose number of base stations with which communication is possible is one. When the terminals 31 to 35 exist in the arrangement as illustrated in FIG. 1, the determination is performed in order from the terminal 35 that is the farthest from the base station 24 first. The terminal 35 is not extracted because the number of base stations with which communication can be performed is 2, and the terminal 35 is determined with respect to the terminal having the next longest distance from the base station 24. This is repeated, and the terminal 31 having the longest distance from the base station 24 is extracted from the terminals having the number of base stations that can communicate with each other.

  Next, the distance between the extracted terminal 31 and the base station 24 is set as a cell radius in the cell setting unit 56, and communication as a base station is started. In this case, the cell radius is 14b (see FIG. 1).

  Note that the present invention is not limited to the above-described embodiment, and can be changed as appropriate without departing from the spirit of the present invention.

  The operations related to the determination of the cell radius method in the base station described in the first and second embodiments of the invention are as follows: ASIC (Application Specific Integrated Circuit), DSP (Digital Signal Processor), MPU (Micro Processing Unit) or CPU (Central Processing Unit). Or a computer system including a combination thereof. Specifically, the computer system may be made to execute a program including an instruction group related to the processing procedure shown in the flowcharts of FIGS. Note that these programs can be stored in various types of storage media accessible by the computer system. The program can be transmitted via a communication medium. Here, the storage medium includes, for example, a flexible disk, a hard disk, a magnetic disk, a magneto-optical disk, a CD-ROM, a DVD, a ROM cartridge, a battery-backed RAM memory cartridge, a flash memory cartridge, a nonvolatile RAM cartridge, and the like. . In addition, the communication medium includes a wired communication medium such as a telephone line, a wireless communication medium such as a microwave line, and the Internet.

1 Location Information System 11-13 Cell 14a Covered by Existing Base Station Maximum Cell 14b Covered by New Base Station New Covered Base Station Cell 14c Covered by HighPower Mode Covered by LowPower Mode Cells 21 to 23 in the minimum range of the newly installed base station existing base station 24 newly installed base stations 31 to 35 terminal 50 cell radius control unit 51 terminal communication unit 52 position information acquisition unit 53 terminal position information determination unit 54 BTS mode setting Unit 55 received BTS number determination unit 56 cell setting unit 61 BTS communication unit 62 position information acquisition unit 63 BTS number determination unit 64 BTS data transmission unit

Claims (13)

A communication system comprising a plurality of cells, a plurality of base stations that cover each cell, and a plurality of terminals that communicate with each base station,
At least one of the plurality of base stations is an information collecting means for receiving a notification of the number of base stations that can be communicated by terminals existing around the base station and a notification of terminal location information;
A cell that determines a cell radius based on distance information between a terminal and the base station in which the number of other base stations capable of communication is zero, which is calculated from the information obtained by the information collecting means and the position information of the base station A communication system comprising radius control means. The communication system according to claim 1, wherein the cell radius control means sets a cell radius based on a result of determining a terminal capable of communicating with another base station in order from a terminal having a short distance from the own base station. The communication system according to claim 1, wherein the cell radius control unit sets a cell radius based on a result of searching for a terminal that cannot communicate with another base station in order from a terminal that is far from the base station. The communication system according to any one of claims 1 to 3, wherein the at least one base station is a micro base station (HomeBTS). Information collecting means for receiving a notification of the number of base stations with which terminals existing around the base station can communicate and a notification of terminal location information;
A cell that determines a cell radius based on distance information between a terminal and the base station in which the number of other base stations capable of communication is zero, which is calculated from the information obtained by the information collecting means and the position information of the base station A base station comprising a radius control means. The base station according to claim 5, wherein the cell radius control means sets a cell radius based on a result of determining a terminal capable of communicating with another base station in order from a terminal having a short distance from the base station. The base station according to claim 5, wherein the cell radius control means sets a cell radius based on a result of searching for terminals that cannot communicate with other base stations in order from a terminal far from the base station. The base station according to any one of claims 5 to 7, wherein the base station is a micro base station (HomeBTS). A cell radius setting method of a base station,
Obtaining the number of base stations that can communicate from terminals existing around the base station and position information of the terminals;
A cell radius setting comprising: determining a cell radius based on distance information between the base station and a terminal in which the number of other communicable base stations calculated from the acquired information and the location information of the base station is zero Method. The cell radius setting method according to claim 9, wherein the cell radius is determined by determining a cell radius based on a result of determining a terminal capable of communicating with another base station in order from a terminal having a short distance from the base station. The cell radius setting method according to claim 9, wherein the cell radius is determined by setting a cell radius based on a result of searching for a terminal that cannot communicate with another base station in order from a terminal far from the base station. The cell radius setting method according to any one of claims 9 to 11, wherein the base station is a micro base station (HomeBTS). A program for causing a computer to execute cell radius setting of a base station,
Obtaining the number of base stations with which terminals existing around the base station can communicate and location information of the terminals;
For determining a cell radius based on distance information between the base station and a terminal in which the number of other base stations capable of communication is zero, which is calculated from the acquired information and the position information of the base station program.

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