JP2011010210A - Mobile terminal locating method, mobile terminal communication system and mobile terminal - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable a mobile terminal to be located in a femtocell while surely recognizing that a cell detected by the mobile terminal is the femtocell.SOLUTION: To a base station 2b forming the femtocell, a position registration area is set which is different from position registration areas of base stations 2a, 2c forming a macro cell. Thus, when the mobile terminal 1 makes a cell search and detects a femtocell FC2, the mobile terminal 1 receives a position registration area different from macro cells C1, C3 in which the mobile terminal is located up to the moment, as notification information, so that the mobile terminal 1 implements position registration processing on an exchange 3 without fail. In accordance with the position registration processing, the exchange 3 transmits to the mobile terminal 1 information indicating that a cell formed by the base station 2b is a femtocell. The mobile terminal 1 therefore can be located in the femtocell FC2 while surely recognizing that the detected cell is the femtocell.

Description

  The present invention relates to a mobile terminal location method, a mobile terminal communication system, and a mobile terminal.

  In the communication system of a mobile terminal, the communication area of the mobile terminal is composed of “cells” formed by the reach of radio waves from the base station, and the communication area is expanded by providing a plurality of cells. In recent years, there is a so-called “femto cell” that has a smaller range than a cell formed by a normal base station. A conventional base station of a mobile terminal has a communication area with a radius of several hundred meters to several kilometers, and is called a “macro cell” because of its size. On the other hand, the femtocell forms a communication area with a radius of several meters to several tens of meters. By providing the femtocell, the line speed can be improved and the communication environment of the mobile terminal can be improved.

  The mobile terminal searches for a cell and receives predetermined information from the base station of the detected cell, so that the mobile terminal can recognize that the mobile terminal is in the cell. A mobile terminal can communicate by communicating with a base station that forms a cell in which the mobile terminal is located. For example, Patent Document 1 describes a technology that preferentially exists in a cell that has been in the past.

  In the mobile terminal communication system, a plurality of base stations are accommodated in an exchange, and the exchange communicates with the accommodated base stations to manage the base station and the mobile terminals accommodated by the base station. The location of each mobile terminal is registered in the exchange. This range as a unit of location registration is called a “location registration area”, and each base station is associated with a location registration area. Usually, a plurality of adjacent base stations are often associated with the same location registration area. A mobile terminal receives a location registration area from the base station that forms the cell when it is located in a cell, and the received location registration area is different from the location registration area of the cell that was previously located If it is, the location registration process is performed on the exchange.

JP-A-11-196252

  As described above, when a femto cell is provided for improving the communication environment, the femto cell and the macro cell may overlap. For this reason, when a mobile terminal searches for a cell, a plurality of cells including a femto cell and a macro cell may be detected. In such a case, in view of the installation purpose of the femtocell, there is a request to make the mobile terminal preferential to the femtocell. Therefore, it is necessary for the mobile terminal to recognize that the detected cell is a femto cell to be preferentially located.

  Therefore, the present invention has been made in view of such problems, and a mobile terminal capable of being in a femto cell while reliably recognizing that the cell detected by the mobile terminal is a femto cell. It is an object to provide a location method, a mobile terminal communication system, and a mobile terminal.

  In order to solve the above problems, a mobile terminal location method of the present invention includes a mobile terminal, a plurality of base stations capable of wireless communication with the mobile terminal and accommodating the mobile terminal, and an exchange accommodating the plurality of base stations. A mobile terminal located in a macro cell formed as a range communicable by the first base station, and a femto formed as a communicable range by the second base station A mobile terminal location method in which a mobile terminal is located in a cell, wherein the mobile terminal searches for a cell and is transmitted from a base station when the mobile terminal detects a cell in the search step. A broadcast information receiving step for receiving broadcast information including information on the location registration area, and a second location different from the first location registration area corresponding to the macro cell where the mobile terminal was located. Location registration processing step of transmitting a location registration request including a terminal ID for identifying a mobile terminal to the exchange via the second base station in response to receiving registration area information from the second base station When the femtocell information transmitted from the exchange and indicating that the cell formed by the second base station is a femtocell is received, the femtocell information is changed to the femtocell information of the located femtocell. And a femtocell information registration step of registering in the stored femtocell information storage means.

  In addition, the mobile terminal of the present invention is capable of wireless communication with the mobile terminal, and forms a cell as a wireless communicable range, and a location registration in which a cell ID for identifying the cell and its own station are associated with each other It is composed of a plurality of base stations that transmit broadcast information including area information, and an exchange that accommodates the plurality of base stations. The plurality of base stations includes a first base station that constitutes a macro cell, and a femto cell. A mobile terminal in a mobile terminal communication system including a second base station to be configured, and a search means for searching for a cell, and when the cell is detected by the search means, transmitted from the base station, Broadcast information receiving means for receiving broadcast information including information on the location registration area, and second location registration that is different from the first location registration area corresponding to the macrocell that was located by the broadcast information receiving means. A location registration processing means for transmitting a location registration request including a terminal ID for identifying a mobile terminal to the exchange via the second base station in response to reception of area information from the second base station; When the femtocell information transmitted from the exchange and indicating that the cell formed by the second base station is a femtocell is received, the femtocell information is stored as the femtocell information of the located femtocell. And femtocell information registering means for registering in the femtocell information storing means.

  In the mobile terminal location method and mobile terminal of the present invention, a location registration area different from that of the base station forming the macro cell is set in the second base station forming the femto cell. As a result, when the mobile terminal searches for a cell and detects a cell formed by the second base station, a location registration area that is different from the location registration area of the macro cell that has been in the service area is reported. Since the information is received as information, the mobile terminal always performs a process for performing location registration with respect to the exchange. The mobile terminal can receive information that the cell formed by the second base station is a femto cell from the exchange corresponding to this processing. Therefore, the mobile terminal can stay in the femto cell while reliably recognizing that the detected cell is a femto cell. In addition, being in the service area is a state in which the mobile terminal recognizes the cell ID of the detected cell and can communicate with the base station forming the cell while synchronizing.

  In the mobile terminal location method of the present invention, the femtocell information registration step includes the femtocell information, a cell ID for identifying a femtocell formed by the second base station, and a frequency used for searching the femtocell. In addition, the information is registered in the femtocell information storage unit in association with at least one of the information for identifying the scramble code. In this case, the registered frequency or scramble code can be used for the search. Therefore, it is possible to carry out a search for preferentially detecting cells having a high probability of being femtocells.

  The mobile terminal location method of the present invention is a mobile terminal comprising a mobile terminal, a plurality of base stations capable of wireless communication with the mobile terminal and accommodating the mobile terminal, and an exchange accommodating the plurality of base stations. In a communication system, there is a mobile terminal location method for causing a mobile terminal located in a macro cell to be located in a femto cell, wherein the mobile terminal searches for a cell, and the mobile terminal is located in a femto cell. When a cell is detected in the search step, the detection cell ID that identifies the detected cell that is the detected cell and the location registration area information that the detection cell base station that is the base station forming the detection cell has, The detected cell broadcast information acquisition step for receiving the detected cell broadcast information transmitted from the base station, and the mobile terminal acquired in the detected cell broadcast information acquisition step When the detected cell ID matches the cell ID registered in the femtocell information storage means storing the cell ID of the femtocell that has been located, the mobile station moves to the exchange via the detected cell base station. And a priority location registration processing step of transmitting a location registration request including a terminal ID for identifying a terminal.

  In addition, the mobile terminal of the present invention is capable of wireless communication with the mobile terminal, and forms a cell as a wireless communicable range, and a location registration in which a cell ID for identifying the cell and its own station are associated with each other It is composed of a plurality of base stations that transmit broadcast information including area information, and an exchange that accommodates the plurality of base stations. The plurality of base stations include a base station that constitutes a macro cell and a base that constitutes a femto cell. And a femto cell search means for searching for a cell, and when a cell is detected by the femto cell search means, a detected cell that is the detected cell is identified. The detection cell broadcast information transmitted from the base station includes information on the location registration area of the detection cell base station which is the base station forming the detection cell and the detection cell. The cell ID registered in the femtocell information storage means storing the cell ID of the femtocell in which the detected cell ID acquired by the detected cell broadcast information acquisition means and the detected cell broadcast information acquisition means And a priority location registration processing means for transmitting a location registration request including a terminal ID for identifying a mobile terminal to the exchange via the detected cell base station when they match.

  According to the mobile terminal location method and mobile terminal of the present invention, the mobile terminal can store information related to a cell that has been in the service area while recognizing that it is a femto cell. Then, when the cell detected by the search is the same as a cell that has been located while recognizing that it is a femto cell, the location registration processing is performed and the mobile terminal is located in the detected cell. Therefore, it is possible to preferentially stay in a femtocell with a track record of being in the area.

  Further, in the mobile terminal location method of the present invention, the femtocell information storage means associates with the cell ID of the femtocell that has been located, the frequency used for searching the femtocell and the femtocell frequency that is a scramble code, and At least one piece of information for identifying a femtocell scramble code is stored, and the femtocell search step includes at least a femtocell frequency and a femtocell scramble code registered in the femtocell information storage unit. The mobile terminal searches for a cell using any one of them, and the mobile terminal uses the detected cell ID acquired in the detected cell broadcast information acquisition step as the femto cell frequency or the femto cell scramble code used in the search in the femto cell search step. Cell information storage means If there is a match with the cell ID that is registered in association you are, characterized thereby serving the local terminal to the detection cell.

  In this case, since the mobile terminal searches for a cell using the femtocell frequency or the femtocell scramble code used for detecting the femtocell, the mobile terminal may preferentially detect a cell having a high probability of being a femtocell. it can. Furthermore, if the detected cell ID matches the cell ID associated with the femtocell frequency or the femtocell scramble code used for the search, the detected cell ID exists, so that the femtocell can be reliably located. It becomes.

  In the mobile terminal location method according to the present invention, the femtocell search step is performed only during normal standby in which the mobile terminal is in a certain cell. If the femto cell search step is performed when the cell is not located in any cell, the normal macro cell search cannot be performed until the femto cell search is completed. According to this configuration, since a normal search is performed when out of service area, it is possible to stay in a cell that can be detected at that time.

  Also, the mobile terminal location method of the present invention is such that when the mobile terminal does not match the detected cell ID and the cell ID associated with the femtocell frequency or the femtocell scramble code in the femtocell information storage means. The method further includes an other cell search step of searching for a cell using at least one of a frequency other than the femto cell frequency and a scramble code other than the femto cell scramble code.

  In this case, since it is possible to prevent detection of a cell that is not a femtocell with a track record, it is possible to reduce power consumption of the mobile terminal. Further, it is possible to increase the possibility of detecting other femtocells by searching.

  Further, the mobile terminal location method of the present invention, when the mobile terminal has not received priority femtocell information indicating that the detected cell is a femtocell after performing the priority location registration processing step, or When receiving information indicating that location registration has been rejected from the detected cell base station, the same cell ID as the detected cell ID stored in the femtocell information storage means, and the frequency and scramble code associated with the cell ID A femtocell information erasing step for erasing is further included.

  Even though the mobile terminal recognizes that it is a femto cell and stores the cell ID of the femto cell in the femto cell information storage means, the cell identified by the cell ID is changed from a femto cell to a macro cell. May be. In addition, the base station is set so that only a predetermined mobile terminal can be located, and information indicating that location registration is rejected is returned to the mobile terminal for other mobile terminals. There is a case. According to the above configuration, in the femto cell search step, it is possible to prevent searching for a cell that is not a femto cell and searching for a cell that is not permitted to be located.

  The mobile terminal location method of the present invention is a mobile terminal comprising a mobile terminal, a plurality of base stations capable of wireless communication with the mobile terminal and accommodating the mobile terminal, and an exchange accommodating the plurality of base stations. In a communication system, a mobile terminal location method for causing a mobile terminal located in a macro cell to be located in a femto cell, wherein an exchange responds to a location registration request transmitted via a base station by the mobile terminal If the cell formed by the base station intervening the reception of the location registration request is a femto cell, the cell formed by the base station is a femto cell. A femtocell information transmission step of transmitting to the mobile terminal femtocell information indicating that

  In this case, since the femtocell information is transmitted in response to the location registration request transmitted from the mobile terminal, the mobile terminal can recognize that the cell detected by the mobile terminal is a femtocell. Become.

  According to the mobile terminal location method and the mobile terminal of the present invention, the second base station that forms the femto cell has a different location registration area from the base station that forms the macro cell. When a cell search is performed and a femto cell is detected, a location registration area different from the location registration area of the macro cell that has been located so far is received as broadcast information. As a result, the mobile terminal always performs a process for performing location registration with respect to the exchange. Therefore, in the exchange, the cell formed by the second base station is a femto cell according to the location registration process. Information to that effect is transmitted to the mobile terminal. Therefore, the mobile terminal can stay in the femto cell while reliably recognizing that the detected cell is a femto cell.

It is a schematic block diagram of a mobile terminal communication system. It is a functional block diagram of a mobile terminal. 2 is a hardware block diagram of the mobile terminal 1. FIG. It is a figure which shows an example of a structure of a serving cell information storage part and a femtocell information storage part. It is a functional block diagram of a base station. It is a functional block diagram of an exchange. It is a figure which shows the cell and position registration area which each base station forms. It is a flowchart which shows the process of the mobile terminal location method which concerns on embodiment. It is a flowchart which shows the process of the mobile terminal location method which concerns on embodiment. It is a flowchart which shows the process of the femtocell priority search in the mobile terminal location method which concerns on embodiment.

  A mobile terminal location method and a mobile terminal communication system according to an embodiment of the present invention will be described with reference to the drawings. If possible, the same parts are denoted by the same reference numerals, and redundant description is omitted.

  FIG. 1 is a diagram showing a configuration of a mobile terminal communication system 100 that implements a mobile terminal location method according to the present embodiment. The mobile terminal communication system 100 includes a mobile terminal 1, a plurality of base stations 2a to 2c capable of wireless communication with the mobile terminal 1, and accommodating the mobile terminal 1, and an exchange 3 accommodating the plurality of base stations 2a to 2c. Composed. The base station 2a forms a macro cell C1 that is a radio wave reachable range. In the example shown in FIG. 1, the mobile terminal 1 is located in the macro cell C1 and can communicate with the base station 2a. Further, the base station 2b forms a femtocell FC2. Furthermore, the base station 2c forms a macro cell C3. In FIG. 1, the concept of the cell is schematically shown.

  FIG. 2 is a block diagram showing a functional configuration of the mobile terminal 1. Functionally, the mobile terminal 1 includes a communication unit 10, a search control unit 11 (search means, femtocell search means), a broadcast information acquisition unit 12 (broadcast information reception means, detected cell broadcast information acquisition means), and a location registration process. Control unit 13 (location registration processing means, priority location registration processing means, femtocell information registration means), serving cell information storage unit 14, femtocell information storage unit 15 (femtocell information storage unit), cell serving unit 16 I have.

  FIG. 3 is a hardware configuration diagram of the mobile terminal 1. As shown in FIG. 3, the mobile terminal 1 physically includes a CPU 101, a RAM 102 and a ROM 103 that are main storage devices, an auxiliary storage device 105 such as a hard disk and a flash memory, and input devices such as a keyboard and a mouse that are input devices. 106, a computer system including an output device 107 such as a display, a wireless communication module 104 for performing communication via a mobile terminal wireless communication network, and the like. Each function described in FIG. 2 has the wireless communication module 104, the input device 106, and the output device under the control of the CPU 101 by reading predetermined computer software on the hardware such as the CPU 101 and the RAM 102 shown in FIG. This is realized by operating 107 and reading and writing data in the RAM 102 and the auxiliary storage device 105.

  Hereinafter, each functional element of the mobile terminal 1 will be described in detail with reference to FIG.

  The communication unit 10 is a part that controls wireless communication with the base station 2, and is used for, for example, cell search, reception of broadcast information from the base station 2, location registration processing to the exchange 3 through the base station 2, and the like. . In addition, when the communication unit 10 detects a cell and acquires broadcast information from the base station 2 forming the cell, the communication unit 10 performs control of the area in the cell. In-zone is that the mobile terminal recognizes the cell ID of the detected cell and can communicate with the base station forming the cell while synchronizing. Furthermore, the communication unit 10 monitors the communication state with the base station 2 by detecting the intensity of the received radio wave, etc., and if the communication level deteriorates or goes out of communication range, This is notified to the search control unit 11. The notification information will be described later.

  The search control unit 11 is a part that searches for a cell via the communication unit 10. The cell search is performed using a predetermined frequency and a scramble code. The predetermined frequency and scramble code are stored in the mobile terminal 1 in advance. Further, the search control unit 11 performs preferential femto cell search using the frequency and scramble code registered in the femto cell information storage unit 15.

  The broadcast information acquisition unit 12 is a part that receives broadcast information transmitted from the base station 2. Here, the broadcast information is information that the base station 2 transmits at regular intervals, and includes a cell ID that is information for identifying a cell formed by the base station 2 and location registration area information. The mobile terminal 1 detects and acquires this broadcast information by searching. The location registration area is information for indicating a range where the mobile terminal 1 is located, and each base station 2 stores the location registration area in association with the location registration area. Also, the broadcast information acquisition unit 12 sends the cell ID and the location registration area included in the received broadcast information to the cell location unit 16 as information for storing in the cell location information storage unit 14.

  The location registration processing control unit 13 is different from the location registration area corresponding to the cell in which the location registration area information included in the broadcast information received by the broadcast information acquisition unit 12 from the base station 2 is in the previous area. In this case, the location registration processing is performed on the exchange 3 via the base station 2. In the location registration process, the location registration processing control unit 13 transmits location registration information including the terminal ID, which is information for identifying the terminal itself, and location registration area information, to the exchange 3 as a location registration request.

  The location registration processing control unit 13 is also a part that receives femtocell information transmitted from the exchange 3 via the base station 2. When the location registration information from the mobile terminal 1 is transmitted to the exchange 3 via the base station 2 forming the femto cell, the femto cell information indicates that the cell in which the mobile terminal 1 is located is a femto cell. This is information for notifying the mobile terminal 1 of the fact. Further, when receiving the femto cell information, the location registration processing control unit 13 associates the cell ID for identifying the femto cell with the information for identifying the frequency and the scramble code used for searching for the femto cell. Register in the cell information storage unit 15.

  The serving cell information storage unit 14 is a part that stores information on a cell in which the mobile terminal 1 is located. FIG. 4A is a diagram illustrating an example of the configuration of the serving cell information storage unit 14. In the example shown in FIG. 4A, the serving cell information storage unit 14 is configured to store the cell ID and the location registration area in association with each other.

  The femtocell information storage unit 15 is a part that stores information on femtocells with a track record in which the mobile terminal 1 is located. FIG. 4B is a diagram illustrating an example of the femtocell information storage unit 15. In the example illustrated in FIG. 4B, the femtocell information storage unit 15 is configured to store a cell ID, a frequency ID, and a scramble code in association with a cell number that is a serial number. The frequency ID and the scramble code are information used for cell search. In the present embodiment, the femtocell information storage unit 15 stores the cell ID, the frequency ID, and the scramble code, but stores at least one of the cell ID, the frequency ID, and the scramble code. It is good to be.

  The cell location unit 16 is a part that stores the information of the cell where the terminal is located in the cell location information storage unit 14. The cell location unit 16 acquires the cell ID and the location registration area information included in the broadcast information from the broadcast information acquisition unit 12, and acquires the acquired cell ID and location registration area information. Remember me.

  Next, the base station 2 will be described. FIG. 5 is a block diagram showing a functional configuration of the base station 2. Functionally, the base station 2 includes a radio communication unit 20, a broadcast information control unit 21, a cell attribute storage unit 22, and an exchange communication unit 23. The base station 2 is configured as a computer system. Hereinafter, each functional element of the base station 2 will be described in detail with reference to FIG.

  The wireless communication unit 20 is a part that controls wireless communication with the mobile terminal 1, and is used for receiving information from the mobile terminal 1 and transmitting broadcast information, for example. The wireless communication unit 20 forms a cell that is a range in which communication with the mobile terminal 1 is possible by wireless communication. Each cell is associated with a cell ID which is information for identifying the cell.

  The broadcast information control unit 21 acquires a cell ID, which is information for identifying a cell, and information on a location registration area associated with the base station 2 from the cell attribute storage unit 22, and acquires the acquired information. The notification information is sent to the wireless communication unit 20.

  The cell attribute storage unit 22 is a part that stores a cell ID that is information for identifying a cell formed by the base station 2 and information on a location registration area associated with the base station 2. One base station 2 may form a plurality of cells.

  The exchange communication unit 23 is a part that controls communication with the exchange 3 via the network. For example, transmission of location registration processing information by the mobile terminal 1, reception of various information from the exchange 3 to the mobile terminal 1, etc. Used for.

  Next, the exchange 3 will be described. FIG. 6 is a block diagram showing a functional configuration of the exchange 3. Functionally, the exchange 3 includes a base station transmission / reception unit 30, a terminal location registration control unit 31, and a location information storage unit 32. The exchange 3 is configured as a computer system and physically has the same configuration as the hardware configuration of the mobile terminal 1 shown in FIG. Hereinafter, each functional element of the exchange 3 will be described in detail with reference to FIG.

  The base station transmission / reception unit 30 is a part that controls communication with the base station 2 and is used, for example, for location registration processing from the mobile terminal 1 and transmission of various information to the mobile terminal 1.

  The terminal location registration control unit 31 receives a location registration request transmitted from the mobile terminal 1 via the base station 2, and uses the received location registration information as the location information of the mobile terminal 1. Remember me.

  Further, the terminal location registration control unit 31 recognizes the base station 2 intervening in the location registration process, determines whether or not the base station 2 is a base station forming a femto cell, and the base station 2 If it is a base station that forms a cell, it transmits femtocell information, which is information to that effect, to the mobile terminal 1 that is the transmission source of the location registration information. The exchange 3 has in advance a database (not shown) in which the identifier of the base station 2 is associated with information indicating whether the cell formed by the base station 2 is a femto cell.

  The in-zone information storage unit 32 is a part that stores in-zone information that is information related to the cell in which the mobile terminal 1 that has received the location registration process is stored, and the terminal ID of the mobile terminal 1 and the location registration of the mobile terminal 1 An area and a femto flag indicating whether or not the cell is a femto cell are stored in association with each other. Note that a storage unit having the same function as the location information storage unit 32 may be provided in another server device so that the exchange 3 and the server device can communicate with each other.

  Then, the process sequence of the mobile terminal location method in the mobile terminal communication system of this embodiment is demonstrated using FIGS. FIG. 7 is a diagram showing cells and location registration areas formed by each base station. In the mobile terminal communication system, a plurality of base stations 2 are accommodated in an exchange 3, and the exchange 3 communicates with a plurality of accommodated base stations 2, and the base station 2 and the mobile terminal 1 accommodated in the base station 2. Manage. The location of each mobile terminal 1 is registered in the exchange 3. The location registration area is a range serving as a unit for registering the location of the mobile terminal 1 in the exchange 3. Each base station 2 is associated with a location registration area. In many cases, the same location registration area is associated with a plurality of adjacent base stations 2.

  In the example shown in FIG. 7, it is assumed that the base stations 2a, 2b, and 2c form a macro cell C1, a femto cell FC2, and a macro cell C3, respectively. As shown in FIG. 7, the range of the femtocell FC2 formed by the base station 2b overlaps the range of the macrocell C1 formed by the base station 2a. Further, the base station 2a stores information “C1” as the cell ID and “R1” as the location registration area in the cell attribute storage unit 22a. The base station 2b stores information “FC2” as the cell ID and “R2” as the location registration area in the cell attribute storage unit 22b. The base station 2c stores “C3” as the cell ID and “R1” as the location registration area in the cell attribute storage unit 22c. As described above, the location registration area information associated with the base station 2b is set to be different from the location registration areas of the base stations 2a and 2c around the base station 2b.

  FIGS. 8 to 10 are flowcharts showing processing of the mobile terminal location method implemented in the mobile terminal communication system 100. The processing started from “Start” is the content of processing performed by the mobile terminal 1. FIG.

  First, the communication unit 10 monitors the communication state with the base station 2, and when the communication level deteriorates or falls outside the communication range, the communication unit 10 notifies the search control unit 11 to that effect, and the processing procedure proceeds to step S3. (S1). If the communication level is not deteriorated and the communication range is not reached, the processing procedure proceeds to step S2. The case where the communication level is not deteriorated and is not out of the communication range is a normal standby time in which the mobile terminal 1 is located in any cell.

  In step S2, the search control unit 11 determines whether or not to perform a femtocell priority search (S2). The execution determination of the femtocell priority search can be performed at regular intervals by, for example, timer control. The priority search of the femtocell will be described later in detail with reference to FIG.

  On the other hand, in step S3, the search control unit 11 searches for a cell via the communication unit 10 (S3). The cell search is performed using a predetermined frequency and a scramble code stored in the mobile terminal 1 in advance.

  Subsequently, the search control unit 11 determines whether or not a cell is detected (S4). If a cell is detected, the processing procedure proceeds to step S5. If no cell is detected (S4), the processing procedure returns to step S3.

  The broadcast information control unit 21 of the base station 2 transmits broadcast information including a cell ID, which is information for identifying a cell, and location registration area information associated with the base station 2 at regular time intervals. (S12), the broadcast information acquisition unit 12 of the mobile terminal 1 receives the broadcast information transmitted from the base station 2 (S5).

  Also, the broadcast information acquisition unit 12 sends the cell ID included in the received broadcast information to the cell coverage unit 16 as information on the cell where the terminal is located, and the cell coverage unit 16 acquires the acquired cell. ID information is stored in the serving cell information storage unit 14. Thus, the mobile terminal 1 can be in the detected cell (S5).

  Subsequently, the location registration processing control unit 13 determines whether or not the location registration area included in the broadcast information matches the location registration area of the cell in which the terminal has been located so far (S6). ). In the example shown in FIG. 7, when the cell that has been in the area is the macro cell C1 and the cell detected in step S4 is the macro cell C3, the location registration areas of the macro cells C1 and C3 are both “R1”. Therefore, the mobile terminal 1 is located in the detected macro cell C3 without performing a location registration process to be described later (S7).

  On the other hand, when the cell that has been in the area is the macro cell C1 and the cell detected in step S4 is the femto cell FC2, the location registration area included in the broadcast information is “R2”. Since the location registration area of the cell that has been located so far does not match “R1”, the processing procedure proceeds to step S8 (S6). That is, in this embodiment, since a location registration area different from the location registration area of the surrounding macro cell is set as the femto cell, the mobile terminal 1 searches for the femto cell by searching for the cell when it is located in the macro cell. If detected, the location registration process (S8) is always performed. In the following description, it is assumed that the femtocell FC2 in FIG. 7 is detected in step S4.

  Subsequently, the location registration processing control unit 13 performs location registration processing on the exchange 3 via the base station 2b (S8). In the location registration process, first, a location registration process request including location registration information is transmitted from the mobile terminal 1, and the base station 2b receives the location registration process request (S13). The location registration information includes a terminal ID for identifying the mobile terminal 1 and location registration area information.

  The base station 2b transmits the location registration processing request transmitted from the mobile terminal 1 to the exchange 3 (S15). The exchange 3 performs location registration processing in response to the received location registration processing request (S16).

  Since the exchange 3 has in advance a database (not shown) in which the identifier of the base station 2 is associated with information indicating whether or not the cell formed by the base station 2 is a femtocell, The location registration control unit 31 can recognize the base station 2 intervening in the location registration process and determine whether the base station 2 is a base station that forms a femto cell. When the terminal location registration control unit 31 of the exchange 3 recognizes that the cell formed by the base station 2b intervening in the location registration processing request is a femto cell (S17), the femto cell information, which is information to that effect, Via the station 2b (S19), it transmits to the mobile terminal 1 that is the transmission source of the location registration information (S18).

Subsequently, the location registration processing control unit 13 of the mobile terminal 1 determines whether or not the femtocell information transmitted from the exchange 3 has been received (S9). Since the cell detected in S4 is a macro cell, the mobile terminal 1 is located in the macro cell (S7). On the other hand, when the femtocell information is received, the location registration processing control unit 13
The femtocell information storage unit 15 associates the cell ID “FC2” for identifying the femtocell FC2, the information “fq1” for identifying the frequency used for searching the femtocell, and the information “SC3” for identifying the scramble code. (S10). In this way, the mobile terminal 1 can store information on femtocells with a track record in the femtocell information storage unit 15.

  The mobile terminal 1 is located in the detected femtocell FC2 (S11).

  Next, a process (A) when it is determined in step S2 that a femto cell priority search is performed will be described with reference to FIG. The flowchart shown in FIG. 10 shows a process for preferentially causing the mobile terminal 1 to be located in a femtocell with a track record.

  First, the search control unit 11 performs a cell search using the frequency and scramble code registered in the femtocell information storage unit 15 (S20). Unlike the search in step S3, this search is performed when there is no deterioration in the communication level with the base station 2, that is, during normal standby. Therefore, the search in step S20 is performed even in the state in which the macro cell C1 is located in FIG. 7, and therefore the search is performed even when the mobile terminal 1 is in the overlapping area between the macro cell C1 and the femto cell FC2. In the search, the macro cell C1 and the femto cell FC2 can be detected simultaneously. In this embodiment, in step S21, the search control unit 11 performs a cell search using the frequency and scramble code registered in the femtocell information storage unit 15, but the femtocell information storage The search may be performed using at least one of the frequency and the scramble code registered in the unit 15.

  Subsequently, the search control unit 11 determines whether or not a cell formed by any one of the base stations 2 is detected (S21). If no cell is detected, the processing procedure proceeds to step S22. Accordingly, the mobile terminal 1 stays in the cell that was in the area before the femtocell priority search was performed.

  On the other hand, when a cell is detected (S21), the broadcast information acquisition unit 12 receives and acquires broadcast information transmitted from the base station 2 (S30, S23).

  Subsequently, the broadcast information acquisition unit 12 associates the cell ID included in the broadcast information acquired in step S23 with the frequency and scramble code used in the search (S20) in the femtocell information storage unit 15. It is determined whether or not it matches the ID (S24). In view of the fact that the femtocell priority search is a process aimed at causing the mobile terminal 1 to be located in a cell that has been recognized after being recognized as a femtocell, the cell included in the broadcast information If the ID does not match the cell ID registered in the femtocell information storage unit 15, it is unknown whether or not the detected cell is a femtocell. It is preferable not to make a sphere. Therefore, when the cell ID included in the broadcast information acquired in step S23 does not match the cell ID registered in the femtocell information storage unit 15, the processing procedure proceeds to step S22, and the mobile terminal 1 Is in the cell that was in the area prior to the femtocell priority search.

  In addition, after the process of step S22 is completed, the process starts again from “START” in FIG. 8, and after passing through steps S1 and S2, a cell search is performed in step S20. It is preferable to search for a cell using a frequency and scramble code other than the frequency and scramble code used in the search (another cell search step). For example, when the search control unit 11 has performed a cell search using the cell ID and scramble code corresponding to the cell NO “1” of the femto cell information stored in the femto cell information storage unit 15, It is preferable to use a cell ID and a scramble code corresponding to the subsequent cell NO “2”. When performing a cell search subsequent to step S22, a cell that is not a femtocell with a proven track record is searched by searching for a cell using a frequency and scramble code other than the frequency and scramble code used in step S20. Since it can prevent detecting, the power consumption of the mobile terminal 1 can be reduced. Further, it is possible to increase the possibility of detecting other femtocells by searching. In the present embodiment, in the other cell search step, the search control unit 11 performs a cell search using the frequency and scramble code registered in the femto cell information storage unit 15. The search may be performed using at least one of the frequency and the scramble code registered in the cell information storage unit 15.

  On the other hand, the cell ID included in the broadcast information acquired in step S23 matches the cell ID registered in the femtocell information storage unit 15 (S24), and the location registration area information included in the broadcast information is If the location registration area is different from the location registration area corresponding to the cell that has been in the area, the location registration processing control unit 13 performs terminal location registration control of the exchange 3 via the base station 2 that forms the detected cell. Communication with the unit 31 is performed to perform the position registration process (S25) (priority position registration process step). In this location registration processing, a location registration processing request including location registration information is transmitted from the mobile terminal 1, and the base station 2 receives the location registration processing request. The location registration information includes a terminal ID for identifying the mobile terminal 1 and location registration area information. The base station 2 transmits the received location registration processing request to the exchange 3 (S34). The exchange 3 performs location registration processing in response to the location registration processing request (S32). Since the exchange 3 can recognize whether the cell formed by the base station 2 intervening in the location registration process is a femto cell, the terminal location registration control unit 31 of the exchange 3 intervenes in the location registration process. When recognizing that the cell formed by the base station 2 is a femto cell, the femto cell information indicating that the cell is a femto cell is moved as a source of location registration information according to the location registration process. It transmits to the terminal 1 via the base station 2 (S32, S34). The mobile terminal 1 receives the femtocell information from the base station 2 and ends the location registration process (S25). By this method, the mobile terminal 1 can be in the newly detected femtocell.

  As described above, when the terminal location registration control unit 31 of the exchange 3 recognizes that the cell formed by the base station 2 involved in the location registration process is a femto cell, the terminal location registration control unit 31 confirms that the cell is a femto cell. The femtocell information shown is transmitted to the mobile terminal 1 that is the transmission source of the location registration information in accordance with the location registration process. However, in the base station 2b forming the femtocell, the setting is made so that only the specific mobile terminal 1 can be located, and the location registration processing from the mobile terminals 1 other than the specific mobile terminal 1 has been performed. In some cases, information indicating that location registration is rejected may be returned. Therefore, in step S26, the location registration processing control unit 13 of the mobile terminal 1 determines whether information indicating that location registration has been rejected has been received or whether femtocell information has not been received (S26). If the location registration rejection information has been received or the femtocell information has not been received, the location registration processing control unit 13 uses the cell ID related to the cell stored in the femtocell information storage unit 15. Then, information regarding the frequency and scramble code associated with the cell ID is deleted (S27). Although the mobile terminal 1 recognizes that it is a femto cell and stores the cell ID of the femto cell in the femto cell information storage unit 15, the cell identified by the cell ID is, for example, a macro cell from the femto cell. The operation may be changed. By erasing such cell-related information from the femtocell information storage unit 15, unnecessary cell search can be prevented.

  Thereafter, the processing procedure proceeds to step S22, and the mobile terminal 1 stays in the cell that has been in the area before the femtocell priority search is performed. In addition, when a some cell is detected in step S20, the process shown to step S23-S27 is performed for every detected cell.

  On the other hand, when the information indicating that the location registration is rejected is not received and the femtocell information is not received, the communication unit 10 performs a process of staying in the detected cell, and the broadcast information acquisition unit 12 The cell ID included in the broadcast information acquired in step S23 is sent to the cell location unit 16, and the cell location unit 16 stores the acquired cell ID in the location cell information storage unit 14 (S28). With the processing procedure described above, the mobile terminal 1 can preferentially stay in a femtocell with a track record of being in the area.

  Then, the operation effect of the mobile terminal location method of this embodiment demonstrated above, the mobile terminal communication system 100, and the mobile terminal 1 is demonstrated. In the mobile terminal location method and the mobile terminal communication system according to the present embodiment, the base station 2b that forms the femtocell has a location registration area “that is different from the location registration area“ R1 ”of the base stations 2a and 2c that form the macrocell. R2 "is set. As a result, when the search control unit 11 of the mobile terminal 1 searches for a cell and detects the femtocell FC2, the broadcast information acquisition unit 12 determines the positions of the macrocell C1 and the macrocell C3 that have been located so far. Since the location registration area “R2” different from the registration area “R1” is received as the broadcast information, the location registration processing control unit 13 of the mobile terminal 1 always performs the location registration processing on the exchange 3. In response to this location registration process, the terminal location registration control unit 31 of the exchange 3 transmits information to the mobile terminal 1 that the cell formed by the base station 2b is a femto cell. Accordingly, the mobile terminal 1 can stay in the femto cell while reliably recognizing that the detected cell is a femto cell.

  Further, in the mobile terminal location method and the mobile terminal communication system 100 according to the present embodiment, the location registration processing control unit 13 of the mobile terminal 1 recognizes that it is a femto cell, and has a cell ID related to a cell that has been in the area In addition, the frequency and scramble code information used for searching the cell is registered in the femtocell information storage unit 15. Furthermore, since the search control unit 11 searches for a cell using the frequency and scramble code used for detecting the femto cell, it can preferentially detect a cell having a high probability of being a femto cell. Then, when the detected cell is the same as the cell registered in the femtocell information storage unit 15, the mobile terminal is located in the detected cell, so that the mobile terminal 1 detects that the detected cell is a femtocell This makes it possible to preferentially stay in a femtocell with a track record of being in the area.

  In the above-described embodiment, the mobile terminal 1 detects a femto cell and searches for a cell for registering the femto cell information in the femto cell information storage unit 15. Although periodic searches are illustrated, the search is not limited to these. For example, the mobile terminal 1 may be arranged in a place where it is known in advance that a femto cell is detected, and the mobile terminal 1 may be caused to perform location registration processing by the user's operation at that place. Further, when the mobile terminal 1 acquires broadcast information and acquires a new location registration area that is different from the location registration area of the cell that has been in the area, the femto cell related to the femto cell belonging to the new location registration area. Cell information may be notified from the exchange 3 to the mobile terminal 1.

DESCRIPTION OF SYMBOLS 1 ... Mobile terminal, 2 ... Base station, 3 ... Switch, 10 ... Communication part, 11 ... Search control part, 12 ... Broadcast information acquisition part, 13 ... Location registration process control part, 14 ... In-zone cell information storage part, 15 DESCRIPTION OF SYMBOLS: Femtocell information storage part, 16 ... Cell location part, 20 ... Radio communication part, 21 ... Broadcast information control part, 22 ... Cell attribute storage part, 23 ... Switch communication part, 30 ... Base station transmission / reception part, 31 ... Terminal Location registration control unit, 32 ... located area information storage unit, 100 ... mobile terminal communication system, C1, C3 ... macro cell, FC2 ... femto cell.

Claims (10)

In a mobile terminal communication system comprising a mobile terminal, a plurality of base stations capable of radio communication with the mobile terminal and accommodating the mobile terminal, and an exchange accommodating the plurality of base stations, the first base A mobile terminal location method for causing a mobile terminal located in a macro cell formed as a communicable range by a station to be located in a femto cell formed as a communicable range by the second base station, ,
A search step in which the mobile terminal searches for a cell;
When the mobile terminal detects a cell in the search step, a broadcast information receiving step of receiving broadcast information transmitted from the base station and including information on a location registration area of the base station;
In response to the mobile terminal receiving from the second base station information of a second location registration area different from the first location registration area corresponding to the macro cell that was in the area, A location registration processing step of transmitting a location registration request including a terminal ID for identifying the mobile terminal to the exchange via the base station;
When receiving the femtocell information transmitted from the exchange and indicating that the cell formed by the second base station is a femtocell, the femtocell information of the femtocell in which the femtocell is located is received. And a femtocell information registration step of registering in the femtocell information storage means storing the mobile terminal location method. The femtocell information registration step includes:
The femtocell information is associated with at least one of a cell ID for identifying a femtocell formed by the second base station, information for identifying a frequency and a scramble code used for searching for the femtocell. The mobile terminal location method according to claim 1, wherein the mobile terminal is registered in the femtocell information storage unit. In a mobile terminal communication system comprising a mobile terminal, a plurality of base stations capable of wireless communication with the mobile terminal and accommodating the mobile terminal, and an exchange accommodating the plurality of base stations, the mobile terminal is located in a macro cell. A mobile terminal location method in which a mobile terminal is located in a femtocell,
A femto cell search step in which the mobile terminal searches for a cell; and
When the mobile terminal detects a cell in the femtocell search step, a detection cell ID that identifies a detection cell that is the detected cell and a detection cell base station that is a base station that forms the detection cell have A detected cell broadcast information acquisition step for receiving detected cell broadcast information transmitted from the base station, including information on a location registration area;
When the mobile terminal matches the cell ID registered in the femtocell information storage means storing the cell ID of the existing femtocell in the detected cell broadcast information acquisition step. A priority location registration processing step of transmitting the location registration request including a terminal ID for identifying the mobile terminal to the exchange via the detection cell base station;
A mobile terminal location method characterized by comprising: The femtocell information storage means associates with the cell ID of the existing femtocell and at least any one of the information for identifying the femtocell frequency and the femtocell scramble code that are the frequency and scramble code used for the search of the femtocell. Remember one,
In the femto cell search step, the mobile terminal searches for a cell using at least one of the femto cell frequency and the femto cell scramble code registered in the femto cell information storage unit,
In the femtocell information storage unit, the mobile terminal acquires the detected cell ID acquired in the detected cell broadcast information acquisition step in the femtocell frequency or the femtocell scramble code used for the search in the femtocell search step. The mobile terminal location method according to claim 3, wherein when the cell ID matches with the registered cell ID, the mobile terminal is located in the detected cell.   5. The mobile terminal location method according to claim 3, wherein the femto cell search step is performed at a normal standby time in which the mobile terminal is located in any cell. 6.   When the mobile terminal does not match the detected cell ID and the cell ID associated with the femtocell frequency or the femtocell scramble code in the femtocell information storage unit, The mobile terminal according to any one of claims 3 to 5, further comprising another cell search step of searching for a cell using at least one of a frequency and a scramble code other than the femtocell scramble code. Area method. When the mobile terminal has not received the priority femtocell information indicating that the detected cell is a femtocell after performing the priority location registration processing step, or the location registration from the detected cell base station When information indicating rejection is received, the same cell ID as the detected cell ID stored in the femtocell information storage unit, the frequency associated with the cell ID, and the scramble code are deleted. The mobile terminal location method according to any one of claims 3 to 6, further comprising a femtocell information erasing step. In a mobile terminal communication system comprising a mobile terminal, a plurality of base stations capable of wireless communication with the mobile terminal and accommodating the mobile terminal, and an exchange accommodating the plurality of base stations, the mobile terminal is located in a macro cell. A mobile terminal location method in which a mobile terminal is located in a femtocell,
A location registration processing execution step in which the exchange performs a location registration process in response to the location registration request transmitted by the mobile terminal via the base station;
When the cell formed by the base station intervening in receiving the location registration request is a femto cell, the switch moves the femto cell information indicating that the cell formed by the base station is a femto cell. A mobile terminal location method comprising: a femtocell information transmission step for transmitting to a terminal. Broadcast information including a mobile terminal and location registration area information that is wirelessly communicable with the mobile terminal, forms a cell as a wireless communicable range, and identifies a cell ID and the own station. And a switch that accommodates the plurality of base stations. The plurality of base stations include a first base station that constitutes a macro cell and a second that constitutes a femto cell. The mobile terminal in a mobile terminal communication system including the base station,
A search means for searching for a cell;
Broadcast information receiving means for receiving broadcast information transmitted from the base station and including information on a location registration area of the base station when a cell is detected by the search means;
In response to receiving from the second base station information of a second location registration area different from the first location registration area corresponding to the macro cell that was located by the broadcast information receiving means, Location registration processing means for transmitting a location registration request including a terminal ID for identifying the mobile terminal to the exchange via a second base station;
When receiving the femtocell information transmitted from the exchange and indicating that the cell formed by the second base station is a femtocell, the femtocell information of the femtocell in which the femtocell is located is received. And a femtocell information registering means for registering in the femtocell information storing means for storing the mobile terminal. Broadcast information including a mobile terminal and location registration area information that is wirelessly communicable with the mobile terminal, forms a cell as a wireless communicable range, and identifies a cell ID and the own station. A plurality of base stations transmitting a plurality of base stations and an exchange accommodating the plurality of base stations, and the plurality of base stations include the base station configuring a macro cell and the base station configuring a femto cell. The mobile terminal in a mobile terminal communication system included,
A femto cell search means for searching for a cell;
When a cell is detected by the femto cell search means, a detection cell ID for identifying a detection cell that is the detected cell, and information on a location registration area that the detection cell base station that is a base station forming the detection cell has Detecting cell broadcast information acquisition means for receiving detected cell broadcast information transmitted from the base station,
When the detected cell ID acquired by the detected cell notification information acquisition unit matches the cell ID registered in the femto cell information storage unit storing the cell ID of the existing femto cell, the detected cell A mobile terminal comprising: priority location registration processing means for transmitting the location registration request including a terminal ID for identifying the mobile terminal to the exchange via a base station.

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