KR20020070618A - Method for managing location region of mobile station - Google Patents

Abstract

PURPOSE: A method for managing a location area of a mobile terminal is provided to automatically setting a size of a location area correspondingly to the mobility of the terminal, so as to minimize paging costs and location area updating costs. CONSTITUTION: An MSC(Mobile Switch Center) decides whether a terminal reaches a location registration updating time(S1). If so, the MSC detects BSs(Base Stations) communicating with the terminal and decides whether the detected BSs are arranged within a location area for the corresponding terminal(S2). If so, the steps are ended, and if not, the MSC detects location information on the BSs and time information(S4). The MSC detects a moving speed of the terminal(S5). If the moving speed of the terminal is over 100Km, the MSC sets the location area to have 19 cells(S6,S7). If the moving speed of the terminal is between 60Km and 100Km, the MSC sets the location area to have 7 cells(S8,S9). If the moving speed of the terminal is under 60Km, the MSC sets the location area to have 1 cell(S10). And the MSC stores cell information configuring the location area in a VLR(Visitor Location Register)(S11).

Description

Location area management method of mobile terminal {METHOD FOR MANAGING LOCATION REGION OF MOBILE STATION}

The present invention relates to a location management method of a terminal in a mobile communication network, and more particularly, to a location area management method of a mobile terminal for setting a location area size in consideration of the movement of the mobile terminal.

In order for the mobile communication system to guarantee multimedia services such as voice, data, and video information, the system capacity must be increased. However, since frequency resources for determining system capacity are limited, methods of increasing user demand with limited frequency resources have been studied. Switching from analog to digital communication, multiple access (eg frequency division multiple access), time division multiple access, code division multiple access (Code) to increase frequency resources Divisin Multiple Access) has been proposed and used to miniaturize cells and divide them into a plurality of cells to enable reuse of the same frequency.

Meanwhile, a method of miniaturizing and dividing a cell has an advantage of increasing efficiency by reusing a frequency as described above, but has a disadvantage of increasing handoff and cost of updating a location of a terminal. In this case, the handoff refers to a phenomenon in which a base station that mediates communication with the terminal is changed by moving between cells having a base station, and a location update cost refers to a case in which the terminal moves from one location area to another location area. The cost of the system incurred when registering a location in the location area to which it belongs. Since the terminal has mobility, the mobile communication system must know the current position of the terminal, that is, which cell position, so that the terminal can communicate with the terminal through the base station of the cell. Accordingly, the mobile communication system should know the cell where the terminal is located, but this method, that is, the method of storing the cell where the terminal is located one by one causes an increase in the storage cost, and as a result, a plurality of cells ( A method of setting C1-Cn to one location area P1-Pn is used. That is, the position of the terminal is determined horizontally belonging to a certain location area (P1-Pn), and when the communication between the terminal and the mobile communication system is required, the repeaters in all the cells (C1-Cn) belonging to a specific location area (for example, P1). Paging the terminal using all to detect the cells (C1-Cn) in which the terminal is located.

As described above, a method of updating one location by configuring one location area P1-Pn with the same number of cells and moving the terminal to another location area P1-Pn is called a fixed area management method. Correspondingly, there is a dynamic area management method. Dynamic realm management is divided into time-based dynamic realm management and movement-based dynamic realm management. The time-based dynamic area management method is a method of updating the location area of the terminal at fixed time intervals regardless of the mobility and call coverage of the mobile terminal, and the mobile-based dynamic area method is used when the terminal crosses a predetermined number of cells. It is a method of updating a position every time. This dynamic area management method does not require the update of the location area substantially when the UE continues to reciprocate between two cells in one location area, but when the UE moves a predetermined time interval or a predetermined number of cells. There is a problem that the location area must be updated every time.

On the other hand, the fixed area management scheme described above has a problem that the size of the location areas P1-Pn and the paging cost are inversely proportional to each other. If the location area P1-Pn is small, that is, composed of a small number of cells, the cost of updating the location area increases due to the mobility of the terminal, but the location of the terminal among the plurality of cells in the location area P1-Pn increases. The paging cost of detecting a cell to be reduced is reduced. On the contrary, when the location area P1-Pn is large, that is, composed of a large number of cells, the cost of updating the location area due to the mobility of the UE is reduced, but the terminal among the plurality of cells in the location area P1-Pn is reduced. There is a problem that the paging cost of detecting this located cell increases.

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem, and an object of the present invention is to provide a method for managing a location area of a mobile terminal, which can minimize a paging cost and a location area update cost by automatically setting the size of the location area corresponding to the mobility of the terminal. To provide.

In order to achieve the above object, the present invention provides a method for setting a location area for the same terminal, comprising: determining whether the mobile terminal is located outside a preset location area; Detecting a moving speed of the mobile terminal when the mobile terminal is located outside a preset location area; Setting a location area for the mobile terminal and a size of the location area corresponding to the moving speed; And storing the set location area and cell information in the location area.

1 is a view showing one location area by a fixed area management method in a conventional mobile communication system,

2 is a schematic block diagram of a mobile communication system for performing a location area management method of a mobile terminal according to the present invention;

3 is a flowchart illustrating a method for managing a location area of a mobile terminal according to the present invention;

4 illustrates an example of location areas having a different number of cells in accordance with the present invention.

<Description of the symbols for the main parts of the drawings>

10: terminal 30: mobile communication exchange

40: Home Location Register 50: Visit Location Register

BS1-BSn: Base Station

Hereinafter, with reference to the accompanying drawings will be described an embodiment of the present invention;

2 is a schematic block diagram of a mobile communication system for performing a method for managing a location area of a mobile terminal according to the present invention. Reference numeral 10 denotes a mobile station, and the subscriber can wirelessly connect to the network using the terminal. A base station (BS1-BSn) mediates communication between the terminal 1 and the mobile switch center (Mobile Switch Center: MSC) 30. The base station (BST) 21 is a BTS (Base Tranceiver System; BTS) 21 and It consists of a base station controller (BSC) 22. Here, the BTS 21 is composed of one or more transceivers located in a predetermined place to perform a wireless communication with the terminal 10. The BSC 22 is a device for controlling the BTSs 21 and exchanges messages between the BTSs 21 and the MSCs 30. A plurality of such base stations BS1-BSn may be connected in one MSC 30, and a geographical location of one base station BS1-BSn is called a cell.

The MSC 30 refers to an automatic system for interfacing user communication from a wireless network to a wired network or a wireless network. The MSC 30 includes a database 31 having distance information between cells as described below for carrying out the present invention. do.

The Home Location Register (HLR) 40 refers to a functional device that stores subscriber information (eg, user file, current location) to manage mobile subscribers. The HLR 40 may be located integrated with the MSC 30 or may be located independently of the MSC 30, and may serve a plurality of MSCs 30 with one HLR 40.

The Visited Location Register (hereinafter referred to as VLR) 50 is connected to one or more MSCs 30, and the HLR 40 when the subscriber is located in an area (host) covered by the VLR 50. Means a functional device for storing subscriber information obtained from &lt; RTI ID = 0.0 &gt; When the mobile terminal 10 enters a new service area encompassed by the MSC 30, the MSC 30 requests and reads information about the terminal 10 from the HLR 40 to the associated VLR 50. Store in In addition, the VLR 50 stores information about the location area where the terminal 10 is located and cells belonging to the location area, and the size of the location area is variably changed as will be described later.

3 shows an operational flowchart of the MSC 30 embodying the present invention. As shown, the MSC 30 of the present invention determines whether the current time point is the location registration update time point of the terminal 10 (S1). The location registration update time point of the terminal 10 is largely classified into three types. First, when the power of the terminal 10 is turned on / off, the terminal 10 communicates with the base station BS1-BSn, so that the MSC 30 transmits the current location area of the terminal 10 and the corresponding cell. It can be seen. The second is a case where the terminal 10 communicates with the base station BS1-BSn at predetermined time intervals in the power-on state, and the third is a case where the terminal 10 is communicating with the base station BS1-BSn. Even in this case, the MSC 30 may know which cell in the current location area and the location area of the terminal 10 is communicating.

As a result of the determination in step S1, if the location registration is an update time point, the MSC 30 proceeds to step S2 to detect the base station BS1-BSn communicating with the terminal 10, and detects the detected base station BS1-BSn. ) Determines whether the base station in the location area for the terminal 10 (S2). As a result of the determination in step S2, when the terminal 10 is within a preset location area, that is, when the base stations BS1-BSn communicating with the terminal 10 are base stations in the location area, the location registration is updated. Although the process is terminated, if the terminal 10 is not in the preset location area, the location area update process needs to be performed.

In step S3, the MSC 30 may provide information on which base station the base station (one of BS1-BSn) is in communication with the terminal 10 and the current time point (time: this time will eventually register the location of the terminal 10). It will be a time to update the) to the terminal 10 and stored in the database 31 while the old base station (BS1-BSn) information and time information (previous location registration) stored corresponding to the terminal 10 Update time) is read. Then, the MSC 3 detects the distance information between the currently detected base station BS1-BSn (eg BS1) and the previous base station (eg BS3) from the database 31 (S4). Here, the method of storing the distance information between the base stations (for example, BS1 and BS3) in the database 31 may use various methods. For example, the mutual distance between base stations BS1-BSn is stored one by one and directly uses this information, and only the latitude and longitude information of the base stations BS1-BSn are stored, and the distance between the base stations is determined using the latitude and longitude information. The detection method may also be employed.

By this process, the MSC 30 detects the moving speed of the terminal 10 by knowing the elapsed time until the terminal 10 is updated and the distance between the location-updated base stations BS1-BSn. It may be (S5).

After detecting the moving speed of the terminal 10, the MSC 30 performs a process of setting the location area according to the moving speed. The present invention is characterized by variously setting the size of the location area according to the moving speed of the terminal 10. In the present embodiment, the size of the location area is divided into three types. For example, when the moving speed of the terminal 10 is 100Km or more, the location area has 19 cells as shown in FIG. 4A (S6, S7), and when the moving speed of the terminal 10 is between 60Km-100Km, FIG. As shown in 4b, the location area has 7 cells (S8 and S9), and when the moving speed of the terminal 10 is 60 km or less, the location area is set to have 1 cell as shown in FIG. 4C (S10). It should be noted that the number of cells shown in FIG. 4 is for ease of description and that the implementation conditions are differently set according to the environment when the present invention is implemented. In addition, it is easily understood by those skilled in the art that the cells included in the above-described location area should be set based on the cell C0 where the terminal 10 to be registered is located. will be.

In step S6 to step S10, the MSC 30 that has set up a location area centered on the cell C0 where the terminal 10 is located is configured as cell information (that is, base station BS1-BSn) information constituting the location area. And stored in the VLR (50) (S11).

As can be seen from the above description, the location area in the present invention is not fixed but is variably set, and the number of cells in the location area increases when the mobility of the terminal 10 is large, that is, the moving speed is large. When the moving speed is small, it can be seen that the number of cells in the location area decreases. In the case of a subscriber with a large moving speed, the mobility is large, so that the location area is large. In the case of a subscriber with a small moving speed, the location area is small because the mobility is small. In this case, it can be seen that there is almost no movement in the case of the subscriber with low mobility, and therefore, the update of the location area rarely occurs. In this case, since the location area is small, that is, the number of cells in the location area is small, so that the updating cost of the location area is low and the paging cost can be minimized. On the contrary, in the case of a subscriber having a large mobility, the location area is large, that is, the number of cells in the location area increases, so that the paging cost may increase, but the updating cost of the location area may be minimized. Therefore, according to the present invention, the paging cost for the mobile subscriber is increased, but the updating cost and the paging cost of the entire location area can be reduced.

As described above, in the present invention, the update cost and the paging cost for the location area can be reduced as a whole by adjusting the size of the location area in consideration of the mobility of the subscriber.

Claims (2)

A location area setting method for a mobile terminal, Determining whether the mobile terminal is located outside a preset location area; Detecting a moving speed of the mobile terminal when the mobile terminal is located outside a preset location area; Setting a location area for the mobile terminal and a size of the location area corresponding to the moving speed; And storing the set location area and cell information in the location area. The method of claim 1, Determining whether the mobile terminal is located outside the preset location area, Determining whether a base station communicating with the terminal is a base station within a preset location area when the terminal is turned on / off; The terminal communicating with a predetermined base station at a predetermined time interval, and determining whether the base station communicating with the terminal is a base station within the preset location area; And determining whether a base station communicating with the terminal in a call is a base station within the preset location area.