KR100294044B1 - Method for tracking the location of mobile station using atm swithch in mobile communication system - Google Patents

Abstract

PURPOSE: A method for tracing a position of an MS(Mobile Station) using an ATM(Asynchronous Transfer Mode) switch is provided to more quickly trace the position of the MS by multicasting calling fact to all VLRs(Visitor Location Registers) using the ATM switch. CONSTITUTION: When a call for calling an MS is generated in a certain telephone and the generated call is inputted to an EO(End Office), the EO confirms an identification number of the called MS. The EO retrieves a table and confirms whether VLRs corresponding to the identification number of the MS exist. The EO multicasts the identification number of the MS through an ATM switch connected to the confirmed VLRs.

Description

Location tracking method of wireless mobile terminal using ATM switch {METHOD FOR TRACKING THE LOCATION OF MOBILE STATION USING ATM SWITHCH IN MOBILE COMMUNICATION SYSTEM}

The present invention relates to a wireless mobile communication network, and more particularly to a method for faster tracking of the location of a mobile terminal to be called.

In general, the wireless mobile communication network (Wireless Mobile Communication Network) as shown in Figure 1 is a mobile communication switching center that provides a circuit switching (circuit switching) service to mobile subscribers in conjunction with a public switched telephone network (PSTN) as shown in FIG. (MSC: Mobile Switching Center) 11 to 13. The MSCs 11 to 13 are connected with a base station (BS) that is in charge of wireless communication with a mobile station (MS). The wireless mobile communication network is also provided with a Home Location Register (HLR) and Visitor Location Register (VLR) to enable tracking of the current location of the mobile terminal.

The HLR 20 is a database that stores all the permanent information of the mobile terminal necessary to connect a call to the mobile terminal or provide other mobile communication services, and is usually connected to only one MSC 11. The most important information stored in the HLR 20 is information on the current position of the mobile terminal (address of the VLR). The VLRs 21 to 23 are databases for temporarily storing subscriber information for mobile stations when they enter a jurisdiction and are connected corresponding to MSCs 11 to 13 respectively. That is, in the VLR 21 to 23, if the mobile terminal is currently located as a visitor, an identification number for the mobile terminal is registered. Most of the information stored in the VLRs 21 to 23 is transmitted and stored from the HLR 20 upon location registration.

On the other hand, MSC 11 to 13 to track the location of the mobile terminal to enable the service at all times, conventionally the method of tracking the location of the mobile terminal flow as shown in Figure 2 or shown in Figures 3a, 3b. Was performed according to. The configuration and operation of this flow is described in IEEE TRANSACTIONS ON VEHICULAR TECHNOLOGY, VOL. 45, NO. 1, FEBRUARY 1996, p. 114-116, "Comparing the PCS Location Tracking Strategies."

The processing flow of the mobile terminal position tracking shown in FIG. 2 is according to the standard of IS-41. Now, assuming that a mobile terminal is called from a phone that is connected to the PSTN's End Office (EO) [Step 1], the EO checks the Mobile Identification Number (MIN) and then sends the mobile terminal to HLR 20. Query the position of ([Step 2]). HLR 20 queries the recently registered VLR [Step 3]. The VLR queries the MSC in which the mobile terminal is located to determine if the mobile terminal can receive a call [step 4]. At this time, if the mobile terminal is able to answer the call, the MSC again provides an address for providing a location tracking path to the corresponding VLR, which is notified to the end station via the HLR [step 5]. The location tracking method of the mobile terminal is a well-known technique as proposed in IS-41. However, there is a disadvantage in that the access time is considerably longer because the procedure described above is required every time a single station is called.

3A and 3B are diagrams showing a processing flow of location tracking called a "cache scheme". This cache technique registers the location of mobile terminal that is frequently accessed in the cache memory in the EO. When a certain call occurs, the corresponding VLR is directly connected by using the contents registered in this cache memory without going through the HLR. This is how to do it. If the operation according to the cache technique is successful, location tracking is performed according to the flow shown in Fig. 3A, which is called a "cache hit." However, if the called mobile terminal is located at a different location from that registered in the cache memory, the procedure according to the standard of IS-41 must be performed again as shown in FIG. 3B. The operation when the operation according to the cache technique fails is called a "cache miss". Therefore, applying the cache technique to the mobile terminal with high mobility and low traffic has the disadvantage that it is more inefficient than tracking location according to the standard of IS-41.

Accordingly, an object of the present invention is to provide a method for faster tracking of the location of a mobile terminal in a wireless mobile communication network.

Another object of the present invention is to provide a method for faster tracking of a location even in a mobile terminal having a high mobility in a wireless mobile communication network.

Another object of the present invention is to provide a method for faster tracking of a location even in a mobile terminal with a lot of traffic in a wireless mobile communication network.

Another object of the present invention is to provide a method for more efficiently tracking the position of a mobile terminal in a wireless mobile communication network.

In order to achieve the above object, the present invention provides an asynchronous transmission mode (ATM) switch that provides a wireless service to mobile subscribers by interworking with a public telephone network (PSTN) instead of a mobile communication switching center (MSC) provided in an existing wireless mobile communication network. Used in conjunction. The ATM switch is connected to at least one visitor location registration register (VLR) that registers an identification number (MIN) for the mobile terminal if the mobile terminal is currently located as a visitor. The station EO connected to the PSTN and having at least one subscriber telephone is provided with a location registration information table which stores a plurality of visitor location registration registers (VLRs) in correspondence with a predetermined mobile terminal. When a call for calling a mobile terminal is generated in a predetermined telephone of the wireless mobile communication network configured as described above, the call is introduced to the terminal and the terminal checks the called mobile terminal identification number in response. The end station then searches the location registration information table to determine whether there are any VLRs stored corresponding to the mobile station identification number. When it is determined that there are VLRs stored corresponding to the mobile terminal identification number, the terminal multicasts the mobile terminal identification number through an ATM switch to which the identified VLRs are connected. At this time, only the VLR storing the mobile station identification number is responded to among the multicasted VLRs, and the remaining VLRs are returned.

The present invention can track the location of the called mobile terminal more quickly by multicasting the call facts to all the registered VLRs using the ATM switch when tracking the location of the called mobile terminal in the wireless mobile communication network.

1 is a view showing a connection configuration of a typical wireless mobile communication network.

2, 3A and 3B illustrate a process flow for tracking the position of a wireless mobile terminal according to the prior art.

4 is a view showing a connection configuration of a wireless mobile communication network according to the present invention.

5 is a view showing an example of a location registration table provided for the operation of location tracking according to the present invention.

6A and 6B illustrate a process flow for tracking the location of a wireless mobile terminal in accordance with the present invention.

7a and 7b is a view showing the time required for the operation of the position tracking according to the prior art and the time required for the operation of the position tracking according to the present invention.

DETAILED DESCRIPTION A detailed description of preferred embodiments of the present invention will now be described with reference to the accompanying drawings. First of all, in adding reference numerals to the components of each drawing, it should be noted that the same reference numerals are used as much as possible even if displayed on different drawings. In addition, in the following description of the present invention, if it is determined that a detailed description of a related known function or configuration may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted. In addition, the terms to be described below are terms defined in consideration of functions in the present invention, which may vary according to the intention or custom of the user or chip designer, and the definitions should be made based on the contents throughout the present specification.

4 is a view showing a connection configuration of a wireless mobile communication network implemented for the operation of location tracking according to the present invention. This wireless mobile communication network is configured in a similar form to the wireless mobile communication network shown in FIG. 1, but is used by an Asynchronous Transfer Mode (ATM) switch (S / W) switches 31 to 33 instead of the MSC interworking with the PSTN. There is a big difference in being constructed. These ATM switches 31 to 33 support radio resource management functions similar to MSCs, and a handover function that sustains a call even when a mobile terminal moves during a call. It supports the function to enable the service at all times by tracking the location of the mobile terminal. That is, the ATM switches 31 to 33 provide overall wireless service to mobile subscribers.

According to the related art, the MSC providing the circuit switched service performs only the VLR inquiring about the mobile station identification number provided from the terminal when performing the location tracking function of the mobile station. In contrast, the ATM switch of the present invention can query not only one VLR but also multiple VLRs at once when a mobile station identification number is provided from a terminal. That is, the ATM switch of the present invention can perform a plurality of VLRs when inquiring about the mobile terminal identification number for the location tracking of the mobile terminal. At this time, it should be noted that the VLRs in which the query is made are not performed for the VLRs of all the wireless mobile communication networks, but only for the VLRs registered in advance. This operation is possible because ATM switch supports point-to-multipoint exchange operation at once, so-called ADD function, unlike MSC which only performs exchange operation on one line at a time. . That is, multicasting is performed to search for a mobile communication terminal rather than multicasting in general data transmission. In the following description, the concept of point-to-multipoint means multicasting for a setup message for inspecting a mobile communication terminal.

The location registration table as shown in FIG. 5 is provided inside the end station EO for the operation of location tracking according to the present invention. This location registration information table is structured similarly to the cache memory provided inside the station according to the cache technique. In other words, information in which the mobile terminal is frequently located (the address of the VLR in which the mobile terminal is frequently located) is registered in the location registration table. For example, if the mobile terminal MIN # 1 frequently moves to the position of VLR1 and the position of VLR2, the location registration information for the mobile terminal MIN # 1 may be structured as shown in FIG.

Now, assuming that the subscriber of the telephone station in the terminal station has called the mobile terminal MIN # 1 in the state where the location registration table is structured as shown in FIG. 5, the call enters the terminal as shown in FIG. 6A. do. If there is an incoming call, the end station checks the mobile station identification number (MIN) and searches the location registration information table to determine whether there is a VLR corresponding to the checked mobile station identification number. If a VLR corresponding to the identified mobile terminal identification number is found in the location registration table, the terminal informs all ATM switches to which the identified VLRs are connected. Accordingly, the fact that the mobile terminal is called is multicasted to all VLRs (VLR1 and VLR2) previously registered in the location registration table. At this time, as the mobile terminal is called, multicasting, there will be a response only in the VLR in which the called mobile terminal is located among the VLRs (VLR1 and VLR2). That is, only the VLR in which the mobile terminal identification number is stored will respond.

As shown in the above, FIG. 6B is a view illustrating a processing flow of location tracking between the terminal EO and the VLR VLR1 in which the mobile terminal is actually located. FIG. 6B shows that the location tracking of the mobile terminal is performed in two steps (step 1 and step 2) in the same manner as the process flow of FIG. 2A described in the related art. However, according to the location tracking operation of the present invention, the location tracking operation such as the processing flow of FIG. 2B is not performed. This is because, as the mobile terminal is called, multicasting is performed on all VLRs registered in the location registration table. That is, at the same time, all VLRs registered in the location registration table are notified that the mobile terminal has been called, and at least one of the VLRs will respond. Of course, even in this case, the called mobile terminal may not be located in the region where all the VLRs registered in the location registration table are located. However, the probability that the location tracking operation fails is significantly reduced compared to the processing flow as shown in FIG. 2B.

7A and 7B are views showing the time required for performing the operation of the position tracking according to the cache technique and the time required for the operation of the position tracking according to the present invention. In this case, it is assumed that the calling party is Party A, the called party is Party D, and the VLRs of Party B, C, and D are all registered in the location registration table. Then, when the location tracking operation is performed according to the conventional cache technique, the calling party A performs the location tracking operation in the order of Party B → Party C → Party D. In this case, when the location tracking operation between the calling party and the called party is called, the calling party first sends a SETUP message to the called party, and in response, the called party sends a CONNECT message to the calling party, and finally, the calling party responds to the transmission of the CONNECT message. The CONECT_ACK message is sent to the called party. Accordingly, it takes time t1 × 3 to perform the position tracking operation according to the conventional cache technique. However, it takes only t1 time for the position tracking operation to be performed according to the present invention. In other words, the time of t1 × 2 is shortened.

As described above, the present invention provides a faster mobile terminal by multicasting the call facts to all registered VLRs using an ATM switch when tracking the location of a called mobile terminal located at an arbitrary place in a wireless mobile communication network. There is an advantage to track the location of the.

Meanwhile, in the detailed description of the present invention, specific embodiments have been described, but various modifications may be made without departing from the scope of the present invention. Therefore, the scope of the present invention should not be limited to the described embodiments, but should be defined not only by the scope of the following claims, but also by the equivalents of the claims.

Claims (2)

A public telephone network, an asynchronous transmission mode switch interoperating with the public telephone network and providing a wireless service to mobile subscribers, and at least one asynchronous transmission mode switch connected to the mobile terminal if the mobile terminal is currently located as a visitor. At least one station having visitor location registration registers for registering an identification number for the identification number and a table connected to the public telephone network and having at least one subscriber telephone and storing a plurality of visitor location registration registers corresponding to a predetermined mobile terminal; In the method for tracking the position of a mobile terminal in a wireless mobile communication network comprising: A first step of confirming the called mobile terminal identification number by the terminal station when a call for calling a mobile terminal is generated in a predetermined telephone and entered into the terminal station; A second step of the terminal station searching the table to determine whether there are visitor location registration registers stored corresponding to the mobile terminal identification number; And a third process of the terminal station multicasting the mobile station identification number through an asynchronous transfer mode switch to which visitor location registration registers identified in the second process are connected. The method of claim 1, wherein the identified visitor location registration registers are provided with the multicasted mobile terminal identification number, and responding to the terminal station when the same identification number as the mobile terminal identification number is registered. Positioning method of a mobile terminal, characterized in that further comprises.