JP4894452B2 - Communication system, base station, cell radius setting method and program thereof - Google Patents

Description

  The present invention relates to a communication system, a base station, and a cell radius setting method and program thereof, and more particularly, to a communication system including a micro base station (Home BTS: Home Base Transceiver Station), a base station, and a cell radius setting method and program thereof.

  In the current communication system, it is not uncommon for a mobile phone to exist within a cell where communication is possible and a gap occurs in the cell, making it impossible to make a call. For this reason, there are many calls for a device that enables a mobile phone user to easily make a call even in a call-disabled zone.

  In order to meet such a demand, a micro base station (HomeBTS) is being studied. The ultra-small base station (HomeBTS) is an ultra-compact base station device that can be carried by a base station for households and consumers, and is expected to be widely used in the future with the spread of mobile terminals.

  Usually, the existing base stations (BTS) are installed so that the callable ranges (cells) overlap, and the mobile terminal has information of a plurality of existing base stations (BTS) that can communicate.

  When a micro base station (HomeBTS) is installed and communicated, the required cell radius varies depending on the installation location. Now, if the cell radius of the micro base station (Home BTS) is fixed, it is conceivable that the cell of the existing base station (BTS) and the cell of the micro base station (Home BTS) overlap.

  In such a case, since the cell is expanded to a part that is not originally necessary, not only power consumption is wasted but also the possibility that the line is used by a person other than the original user is increased. Become.

  In consideration of use at home, it is important to suppress power consumption as much as possible, and the cell radius is preferably set to a minimum. Further, the control of the cell radius also reduces the possibility of being disturbed by a person other than the original user, and as a result, increases the commercial value of the micro base station (HomeBTS).

  On the other hand, if the cell radius is too narrow, 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 to the minimum necessary.

  An invention for solving this problem is disclosed in Patent Document 1. This is to reduce the cell radius step by step, and when a mobile device outside the area appears, the mobile device transmits a change stop signal to the base station to stop the cell radius change.

  Other examples of this type of communication system are disclosed in Patent Documents 2 and 3.

JP 2003-087840 A (paragraph 0062 and FIG. 7) JP 2005-328152 A JP 2006-101442 A

  In the invention disclosed in Patent Document 1, a mobile station that is out of the area due to cell reduction does not transmit a change stop signal to a base station if it can connect to another base station. Transmitting means that the mobile station can communicate only with the base station whose cell radius is currently being reduced. Therefore, this means “reducing the cell radius until there is no mobile device capable of communicating with other base stations”, and is the same as the object of the present invention.

  However, the base station in the present invention is configured to receive information on whether or not there is another communicable base station from the mobile terminal and reduce the cell radius based on the information. Such a configuration is patented. It is not disclosed at all in the invention disclosed in Document 1. Therefore, the invention disclosed in Patent Document 1 is completely different from the present invention in configuration.

  Such a configuration is not disclosed in the above-mentioned Patent Documents 2 and 3.

  Therefore, an object of the present invention is to provide a communication system, a base station, a cell radius setting method, and a program capable of reducing the cell radius until a portable terminal exists only in the cell with a completely different configuration from the conventional one. There is.

In order to solve the above problems, a communication system according to the present invention includes a plurality of cells, a plurality of base stations that cover each cell, and a plurality of mobile terminals that communicate with each base station. And one of the base stations includes information collecting means for notifying the number of other base stations that can communicate with mobile terminals existing around the own cell, and the collected number information of the base stations. based looking contains a cell radius control means for controlling the cell size of its own cell, the cell radius control means a cell size of its own cell radius number of communicable mobile terminal and another base station becomes zero It is characterized by setting.

A base station according to the present invention is a base station in a communication system including a plurality of cells, a plurality of base stations that cover each cell, and a plurality of mobile terminals that communicate with each base station. One of the base stations is an information collecting means for notifying the number of other base stations that can communicate to mobile terminals existing around the own cell;
Look containing a cell radius control means for controlling the cell size of its own cell based on the number information of the base station that the collected, the cell radius control means with another base station number of communicable mobile terminals zero The cell radius of the own cell is set as the radius.

In addition, the cell radius setting method according to the present invention includes a cell radius of a communication system including a plurality of cells, a plurality of base stations that cover each cell, and a plurality of mobile terminals that communicate with each base station. A setting method, wherein one of the base stations is configured to notify an information on the number of other base stations that can communicate to mobile terminals existing around the own cell, and the number of the collected base stations. look containing a cell radius control step of controlling the cell size of its own cell based on the information, the cell radius control step, other base stations and cells of the host cell radius number of communicable mobile terminals becomes zero It is characterized by setting a radius.

A program according to the present invention is a cell radius setting method for a communication system including a plurality of cells, a plurality of base stations that cover each cell, and a plurality of mobile terminals that communicate with each base station. An information collection step, which is provided in one of the base stations and causes a computer to notify the number of other base stations that can communicate with a mobile terminal existing around the own cell, and the collected program der for based on the number information of the base station to perform the cell radius control step of controlling the cell size of its own cell is, the cell radius control step, the number of communicable mobile terminal and another base station The cell radius of the own cell is set to a radius where becomes zero.

  Here, the operation of the present invention will be described. In the micro base station (HomeBTS) in the present invention, first, the cell radius is set to the maximum. Next, the number of existing base stations (BTS) that can communicate from mobile terminals existing around the micro base station (Home BTS) is notified. When there are portable terminals that can communicate with a plurality of existing base stations (BTS), the cell radius is reduced by one step in the ultra-small base station (HomeBTS). And the number of the existing base stations (BTS) which can communicate from the portable terminal which exists in the circumference | surroundings of a micro base station (HomeBTS) again is notified. This is executed until there is no portable terminal that can communicate with the existing base station (BTS), and the cell radius is set to the radius when no portable terminal exists.

  According to the present invention, since the above configuration is included, the cell radius can be reduced by a configuration completely different from the conventional configuration until the mobile terminal exists only in the cell.

  Embodiments of the present invention will be described below with reference to the accompanying drawings.

  FIG. 1 is a block diagram of a first embodiment of a communication system according to the present invention. Referring to the figure, the communication system 1 includes cells 11 to 14, an existing base station (BTS) 21 having a cell 11 as a cover area, an existing base station (BTS) 22 having a cell 12 as a cover area, a cell An existing base station (BTS) 23 having a cover area 13, a micro base station (HomeBTS) 24 having a cover area 14, a mobile terminal 31 existing in the cells 12 and 14, and a cell 11 and 14 Mobile terminal 32 and mobile terminal 33 that exists only in the cell 14.

  That is, the present invention is a communication system including existing base stations (BTS) 21 to 23 and a micro base station (Home BTS) 24.

  In the figure, as an example, a cell 14a when the radius of the cell 14 of the micro base station (HomeBTS) 24 is maximum and a cell 14b when it is minimum are shown. In the maximum cell 14a, all of the mobile terminals 31 to 33 exist, and in the minimum cell 14b, only the mobile terminal 33 exists.

  FIG. 2 is a configuration diagram of an example of a micro base station (HomeBTS) 24 according to the present invention. Referring to the figure, the micro base station (HomeBTS) 24 includes antennas 51 and 52, a transmission unit 53, a reception unit 54, a control unit 55, a program storage unit 56, and a storage unit 57. Composed.

  The control unit 55 controls the transmission unit 53, the reception unit 54, the program storage unit 56, and the storage unit 57.

  The program storage unit 56 stores a cell radius setting method program to be described later, and the storage unit 57 stores at least the number of predetermined portable terminals to be described later.

  Next, the operation of the first embodiment of the communication system will be described. FIG. 3 is a flowchart showing the operation of the first embodiment of the communication system according to the present invention. As a precondition, it is assumed that the mobile terminals 31 to 33 exist in the cells 11 to 14 shown in FIG.

  First, a micro base station (HomeBTS) 24 is installed in a place other than the cover area of the cells 11 to 13, for example, indoors such as a house or a store (step S1).

  Next, power is turned on to the micro base station (HomeBTS) 24 (step S2).

  Next, the micro base station (HomeBTS) 24 sets the radius of the cell 14 to the maximum (step S3). The cover area of the cell 14 at this time is defined as a cell 14a (see FIG. 1).

  Next, the number of existing base stations (BTS) capable of communication is notified from the micro base station (Home BTS) 24 to the mobile terminals 31 to 33 existing in the vicinity (step S4).

  In the initial state, one existing base station (BTS) 22 is provided as an existing base station (BTS) with which the mobile terminal 31 can communicate, and the mobile terminal 32 has one existing base station (BTS) 21.

  Therefore, the micro base station (HomeBTS) 24 determines that there is a mobile terminal that can communicate with the existing base station (BTS) (“Yes” in step S5), and decreases the cell radius by a predetermined length (step S6). The cover area of the cell 14 at this time is defined as a cell 14b (see FIG. 1).

  Then, the process returns to step S4. In step S4, the number of existing base stations (BTS) capable of communication is notified from the micro base station (Home BTS) 24 to portable terminals existing in the vicinity.

  At this point, the number of portable terminals that can communicate with the existing base station (BTS) has become zero (“No” in step S5), that is, portable terminals that can communicate only with the micro base station (HomeBTS) 24. Since only 33 exists (see FIG. 1), the micro base station (HomeBTS) 24 sets the cell radius to the radius at that time (step S7). That is, the area of the cell 14 is set to the cell 14b.

  Next, the micro base station (HomeBTS) 24 starts communication as a base station similar to the existing base station (BTS) (step S8).

  The processing in the micro base station (HomeBTS) 24 is executed by the control unit 55 in the micro base station (HomeBTS) 24.

  As described above, according to the first embodiment of the present invention, the cell radius is reduced until the mobile terminal exists only in the cell 14 of the micro base station (HomeBTS) 24 by a completely different configuration. Is possible.

  That is, since the micro base station (Home BTS) 24 automatically sets the cell under each environment, the user of the mobile terminal can easily change the place of use and change without knowing the surrounding environment. Even if this is the case, it is possible to prevent the mobile terminal from being lost. On the other hand, by reducing power consumption, the commercial value of the micro base station (HomeBTS) 24 can be increased.

  FIG. 4 is a block diagram of a second embodiment of the communication system according to the present invention. In the figure, the same components as those in FIG. 1 are denoted by the same reference numerals, and the description thereof is omitted.

  The communication system 41 in FIG. 4 is different from that in FIG. 1 and shows a case where there are two mobile terminals 31 and 33 as an example, which are present only in the cell 14. Further, the distance from the micro base station (HomeBTS) 24 to the mobile terminal 31 is longer than the distance from the micro base station (Home BTS) 24 to the mobile terminal 33, and from the micro base station (Home BTS) 24 to the mobile terminal. The distance to 31 is equivalent to the distance from the micro base station (HomeBTS) 24 to the portable terminal 32.

  In this case, as in the first embodiment, the cell radius is reduced (step of FIG. 3) only by whether or not there is a mobile terminal capable of communicating with the existing base station (BTS) (see step S5 of FIG. 3). In S65), when the mobile terminal 32 is out of the area of the cell 14, the mobile terminal 31 is out of the area.

  Therefore, in the case of the first embodiment, it is necessary to investigate in advance a zone where calls cannot be made by a field survey or the like. The second embodiment aims to solve this problem.

  Next, the operation of the second embodiment of the communication system will be described. FIG. 5 is a flowchart showing the operation of the second embodiment of the communication system according to the present invention. As a precondition, it is assumed that the mobile terminals 31 to 33 exist in the cells 11, 13 and 14 shown in FIG.

  First, the micro base station (HomeBTS) 24 is installed in a place other than the cover areas of the cells 11 and 13 (step S11).

  Next, power is turned on to the micro base station (HomeBTS) 24 (step S12).

  Next, the micro base station (HomeBTS) 24 sets the radius of the cell 14 to a maximum of 14a (see FIG. 4) (step S13). The cover area of the cell 14 at this time is defined as a cell 14a (see FIG. 4).

  Next, the number of existing base stations (BTS) capable of communication is notified from the micro base station (Home BTS) 24 to the mobile terminals 31 to 33 existing in the vicinity (step S14).

  In the initial state, only the mobile terminal 32 has one existing base station (BTS) 21.

  At this stage, the micro base station (HomeBTS) 24 has obtained information that the mobile terminals 31 and 33 can communicate only with the micro base station (HomeBTS) 24. Therefore, the control unit 55 of the micro base station (HomeBTS) 24 stores the number of mobile terminals that can communicate only with the local station (HomeBTS) 24 (“2” in this embodiment) in the storage unit 57 (step S15). And FIG. 2).

  Next, the micro base station (HomeBTS) 24 checks whether or not the number of portable terminals that can communicate with only the local station (HomeBTS) 24 is reduced (step S16).

In the initial flow, the cell radius is not controlled yet at this stage,
The number of portable terminals has not decreased (“No” in step S16).

  Accordingly, the process proceeds to step S17, and the micro base station (Home BTS) 24 checks whether there is a mobile terminal that can communicate with the existing base station (BTS). At this stage, since there is one mobile terminal (mobile terminal 32) that can communicate with the existing base station (BTS) (“Yes” in step S17), the cell radius is reduced by a predetermined length (step S18). The cover area of the cell 14 at this time is defined as a cell 14b (see FIG. 4).

  Then, the process returns to step S14. In step S14, the number of existing base stations (BTS) capable of communication is notified from the micro base station (Home BTS) 24 to portable terminals existing in the vicinity.

  At this stage, the ultra-small base station (HomeBTS) 24 has zero number of portable terminals that can communicate with the existing base station (BTS), and the number of portable terminals that can communicate only with the own station (HomeBTS) 24 is also one. The information that the mobile terminal 33 has decreased is obtained. Therefore, the control unit 55 of the micro base station (HomeBTS) 24 stores the number of portable terminals that can communicate only with the local station (HomeBTS) 24 (“1” in this embodiment) in the storage unit 57 (step S15). And FIG. 2).

  Next, the micro base station (HomeBTS) 24 checks whether or not the number of portable terminals that can communicate with only the local station (HomeBTS) 24 is reduced (step S16). At this stage, since the number of portable terminals that can communicate only with the local station (HomeBTS) 24 has decreased from “2” to “1”, the micro base station (HomeBTS) 24 returns the cell radius to the previous stage. (Step S19). That is, the cover area of the cell 14 is returned to the cell 14a (see FIG. 4).

  Then, the micro base station (HomeBTS) 24 sets the cell radius to the radius at that time (step S20).

  Next, the micro base station (HomeBTS) 24 starts communication as a base station similar to the existing base station (BTS) (step S21).

  The processing in the micro base station (HomeBTS) 24 is executed by the control unit 55 in the micro base station (HomeBTS) 24.

  As described above, according to the second embodiment of the present invention, the minimum cell radius is automatically set within a range in which a part of portable terminals that can communicate only with the micro base station (HomeBTS) 24 does not fall outside the area. It becomes possible to set with. As a result, it is possible to save the trouble of preliminarily examining the call-disabled zone by a field survey or the like.

  The third embodiment relates to a program of a cell radius setting method. As described in the first embodiment, the program storage unit 56 of the micro base station (HomeBTS) 24 stores a program for the cell radius setting method. The program is a program of the cell radius setting method shown in the flowcharts of FIGS.

  The control unit 55 (“computer”) of the micro base station (HomeBTS) 24 reads the program from the program storage unit 56 and controls the transmission unit 53, the reception unit 54, and the storage unit 57 according to the program. Since the contents of the control have already been described, description thereof is omitted here.

  As described above, according to the third embodiment of the present invention, a program for automatically setting a cell in each environment by the micro base station (HomeBTS) 24 is obtained.

1 is a configuration diagram of a first embodiment of a communication system according to the present invention. It is a block diagram of an example of the micro base station (HomeBTS) 24 which concerns on this invention. It is a flowchart which shows operation | movement of 1st Example of the communication system which concerns on this invention. It is a block diagram of 2nd Example of the communication system which concerns on this invention. It is a flowchart which shows operation | movement of 2nd Example of the communication system which concerns on this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1,41 Communication system 11-14 Cell 21-23 Existing base station (BTS)
24 Ultra-small base station (HomeBTS)
31-33 Mobile terminal 51, 52 Antenna 53 Transmitting unit 54 Receiving unit 55 Control unit 56 Program storage unit 57 Storage unit

Claims (10)

A communication system including a plurality of cells, a plurality of base stations that cover each cell, and a plurality of mobile terminals that communicate with each base station,
One of the base stations is information collection means for notifying the number of other base stations that can communicate with mobile terminals existing around the own cell;
Look containing a cell radius control means for controlling the cell size of its own cell based on the number information of the base station that the collected,
The said cell radius control means sets the cell radius of a self-cell to the radius from which the number of the portable terminals which can communicate with another base station becomes zero. One of the base stations further includes storage means for storing the number of portable terminals that can communicate only with the own base station,
  2. The communication according to claim 1, wherein the cell radius control unit returns the cell radius to the previous stage when the number of mobile terminals that can communicate with only the base station decreases as the cell radius is controlled. system. The communication system according to claim 1 or 2, wherein one of the base stations is a micro base station (HomeBTS). A base station in a communication system including a plurality of cells, a plurality of base stations that cover each cell, and a plurality of mobile terminals that communicate with each base station,
  One of the base stations is information collection means for notifying the number of other base stations that can communicate with mobile terminals existing around the own cell;
  Cell radius control means for controlling the cell radius of the own cell based on the collected base station number information,
  The cell radius control means sets the cell radius of the own cell to a radius where the number of mobile terminals capable of communicating with other base stations becomes zero. One of the base stations further includes storage means for storing the number of portable terminals that can communicate only with the own base station,
  5. The base according to claim 4, wherein the cell radius control means returns the cell radius to the previous stage when the number of mobile terminals that can communicate only with the own base station decreases as the cell radius is controlled. Bureau. 6. The base station according to claim 4, wherein one of the base stations is a micro base station (HomeBTS). A cell radius setting method for a communication system including a plurality of cells, a plurality of base stations that cover each cell, and a plurality of mobile terminals that communicate with each base station,
  One of the base stations is an information collecting step for notifying the number of other base stations that can communicate with mobile terminals existing around the own cell;
  A cell radius control step for controlling the cell radius of the own cell based on the collected number information of the base stations,
  In the cell radius control step, the cell radius setting method is characterized in that the cell radius of the own cell is set to a radius where the number of mobile terminals capable of communicating with other base stations becomes zero. One of the base stations further includes a storing step of storing the number of mobile terminals that can communicate only with the own base station,
  8. The cell according to claim 7, wherein, in the cell radius control step, the cell radius is returned to the previous stage when the number of mobile terminals that can communicate only with its own base station is reduced due to the control of the cell radius. Radius setting method. 9. The cell radius setting method according to claim 7, wherein one of the base stations is a micro base station (HomeBTS). A program of a cell radius setting method for a communication system including a plurality of cells, a plurality of base stations that cover each cell, and a plurality of mobile terminals that communicate with each base station,
  An information collecting step that is provided in one of the base stations and causes a computer to notify the number of other base stations that can communicate with mobile terminals existing around the own cell;
  A cell radius control step for controlling a cell radius of the own cell based on the collected number information of base stations,
  The cell radius control step sets the cell radius of the own cell to a radius where the number of mobile terminals capable of communicating with other base stations becomes zero.

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