KR101417931B1 - Roaming Method and System Capable of Keeping Call Quality of Inbound Mobile Communication Terminal - Google Patents

Abstract

The present invention relates to a roaming method and system for maintaining call quality of an inbound mobile communication terminal.

The present invention relates to a method and apparatus for in-band mobile communication terminal having a GSM SIM card and a method for registering a roaming service in a CDMA mobile communication network using a communication standard for CDMA inbound communication, A roaming method, and a system for maintaining the same.

Roaming, GSM, CDMA, inbound mobile communication terminal, GLR, handoff

Description

[0001] The present invention relates to a roaming method and system for maintaining call quality of an inbound mobile communication terminal,

1 is a schematic block diagram of a roaming system according to a preferred embodiment of the present invention;

2 is a schematic flowchart of a roaming service according to a preferred embodiment of the present invention.

Description of the Related Art

100: Inbound mobile communication terminal 110: Base station

120: mobile switching center 130: GSM GLR

140: GSM home network

The present invention relates to a roaming method and system for maintaining call quality of an inbound mobile communication terminal. The present invention relates to a mobile communication terminal, and more particularly, to a mobile communication terminal having a GSM SIM card and a mobile communication terminal, And to a roaming method and system for maintaining the same.

With the recent rapid increase in mobile communication demand, there is a growing demand for roaming services that can be routed to a single number anywhere in the world. [0003] Wireless mobile communication systems mainly used in the world include Global System for Mobile Communication (GSM), Code Division Multiple Access (CDMA), and Time Division Multiple Access (TDMA).

GSM is a variant of the TDMA scheme, in which data is digitized and compressed and then transmitted over a channel together with two user data streams, each of which is transmitted in its own unique time slot. GSM can operate in both the 900 MHz and 1800 MHz frequency bands. GSM is a widely used wireless mobile communication system in Europe and elsewhere, with more than 120 million subscribers worldwide and 120 countries.

On the other hand, CDMA is a code division multiple access digital cellular system developed by Qualcomm, USA, which transmits and receives signals while sharing time and frequency. In the CDMA system, since the same frequency can be used in many cells, the transmission can be stopped while the caller is silent while the interference is less than the other system, and the capacity can be increased 10 times or more than the analog system. In the CDMA method, the quality of the communication is excellent because the signals coming in the multipath are separated and a good signal is selected and used. CDMA is used in Korea and Japan.

GSM service subscribers can use their mobile phones to use wireless mobile communication services in countries where GSM networks operate abroad because GSM network operators also have roaming agreements with foreign operators. However, the process becomes complicated when GSM service subscribers use wireless mobile communication services in CDMA countries.

When a subscriber of a GSM (Global System for Mobile communication) service tries to receive a communication service in a country where a CDMA service is provided, a new terminal is rented and a new subscriber number is given instead of a number used by the subscriber, (SIM) card can be provided to a mobile communication terminal capable of receiving a SIM card to receive a communication service.

However, the inbound roaming service between the CDMA mobile communication network and the GSM mobile communication network is complicated because the communication standard of each communication service is different.

In a communication standard of each mobile communication network, in a CDMA mobile communication network, when a sender transmits a message to a sender, when a message is transmitted from an originating mobile communication terminal, the mobile communication exchange in an area where the originating mobile communication terminal is located receives the message. Upon receiving a message from the mobile switching center, the mobile terminal confirms the called party number of the message and transmits a Short Message Delivery Point-Point (SMDPP) message to the message center. If the message received from the mobile switching center is normal, the message center transmits the SMDPP Ack message to the calling mobile communication terminal. If the message is abnormal, the message center transmits the SMDPP NAK message including the error code to the calling mobile communication terminal. In the message center, the SMSREQ (SMS Request) message is transmitted to the home location register to which the called party number belongs. In the home location register, the received location information is included in the SMSREQ Ack message. The message center obtains the called party location information from the home location register, generates an SMDPP message, and transmits it to the mobile switching center. The mobile switching center transmits a message to the called mobile communication terminal.

On the other hand, the GSM mobile communication network transmits a message to the message center through the FSM (Forward SMS) message at the transmitting mobile switching center when the calling side transmits the SMS message. The message center transmits an FSM Ack message when it receives a normal message, and transmits an FSM NAK message to an originating mobile communication terminal when it receives an abnormal message. The message center then sends an SRI (SendRountingInfoSM) message to the called home location register to inquire the location of the called party. The home location register transmits the location information of the called party to the message center through the SRI Ack (SendRoutingInfoSM Acknowledge) message. The message center transmits the FSM message to the called mobile switching center and the called mobile switching center transmits the message to the called mobile communication terminal.

The procedure of roaming service between mobile communication networks in other mobile communication network area is complicated compared with general communication service because it requires to accommodate both communication standards of CDMA mobile communication network and GSM mobile communication network.

In particular, in the case of roaming service in the CDMA communication service area, the procedure is complicated and the success rate is not high because the terminal authentication and location registration are performed in the foreign GSM home network.

Therefore, when the inbound mobile communication terminal moves in the boundary area of the mobile switching center during the roaming service, the authentication and location registration of the inbound mobile communication terminal performed in the foreign GSM home network causes the communication of the inbound mobile communication terminal in the CDMA communication service area Handoff problem may occur because the communication environment required by the standard SMDPP protocol is not provided.

In order to solve such a problem, the present invention provides a mobile communication system including a GSM sim card, an inbound mobile communication terminal, and an inbound mobile communication terminal, wherein the mobile communication terminal uses a communication standard for CDMA inbound communication in a CDMA mobile communication network, The present invention also provides a roaming method and system for maintaining call quality in mobile terminal.

In order to achieve the above object, the present invention provides a roaming system for providing a roaming service between a Code Division Multiple Access (CDMA) inbound mobile communication network including a mobile switching center and a Global System for Mobile Communication (GSM) An inbound mobile communication terminal equipped with a GSM SIM (Subscriber Identity Module) card, a mobile switching center receiving MIN (Mobile Identity Number) information of an inbound mobile communication terminal, MIN (IMSI) information corresponding to the information to the GSM home network to request the authentication of the inbound mobile communication terminal, receives the authentication vector from the GSM home network, transfers the authentication vector to the mobile switching center, And receives the response information through the mobile switching center and transmits the response information to the GSM home network Wherein the GSM GLR informs the mobile switching center of the normal processing result of the location registration before requesting the location registration with the GSM home network. There is provided a roaming system for maintaining call quality of a communication terminal.

According to another aspect of the present invention, there is provided a roaming method of a roaming system including a CDMA mobile communication network including a mobile switching center, a GSM GLR and a GSM home network, the method comprising: (a) Transmitting MIN information to the switching center; (b) confirming the MIN information of the inbound mobile communication terminal at the mobile switching center and transmitting the MIN information of the GSM inbound mobile communication terminal to the GSM GLR; (c) confirming the inbound mobile communication terminal by checking the MIN information of the inbound mobile communication terminal in the GSM GLR; And (d) notifying the normal processing result of the location registration of the inbound mobile communication terminal from the GSM GLR to the mobile switching center. The roaming method of maintaining the call quality of the inbound mobile communication terminal.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the drawings, the same reference numerals are used to designate the same or similar components throughout the drawings. In the following description of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear.

1 is a schematic block diagram of a roaming system according to a preferred embodiment of the present invention;

The in-bound mobile communication terminal 100 is a system in which a Subscriber Identity Module (SIM) card of a Global System for Mobile communications (GSM) subscriber is installed in a CDMA (Code Division Multiple Access) A mobile communication terminal receiving roaming service in a service area.

The inbound mobile communication terminal 100 may be a CDMA mobile communication terminal that accommodates a User Information Module (UIM) card. Generally, a GSM mobile communication network can use a communication service by attaching a SIM card containing its subscriber profile to a terminal. In a CDMA mobile communication network, however, GSM subscribers mount their SIM card in a CDMA mobile communication terminal, It is possible to use a SIM card of a GSM subscriber by using a mobile communication terminal accommodating a UIM card similar to a SIM card. The inbound mobile communication terminal 100 is not limited to the mobile communication terminal accommodating the UIM card, but may be a mobile communication terminal capable of accommodating the SIM card.

The mobile switching center 120 performs base and supplementary service processing, subscriber's incoming and outgoing call processing, location registration and handoff procedure processing, and interworking with other networks. The mobile switching center 120 according to the preferred embodiment of the present invention transmits and receives signals to and from the inbound mobile communication terminal 100 through the base station 110 and transmits MIN information and authentication vector response information of the inbound mobile communication terminal 100 To the GSM GLR 130 and attempts to register the location.

The GLR (Gateway Location Register) is a device that provides a protocol conversion function for roaming service between mobile communication networks using different MAP (Mobile Application Part) protocols, and is provided in an inbound mobile communication network and a corresponding home network. The GSM GLR 130 refers to the GLR for the GSM communication standard provided in the other mobile communication network. The GSM GLR 130 according to a preferred embodiment of the present invention provides a protocol conversion function for an international roaming service between a CDMA mobile communication network and a GSM mobile communication network in a CDMA mobile communication network area.

The GSM home network 140 refers to a home network of a GSM mobile communication network. The GSM home network 140 according to the preferred embodiment of the present invention includes a GLR and a home location register to perform location registration and subscriber information processing of the inbound mobile communication terminal 100 requested from the GSM GLR 130. [

2 is a schematic flowchart of a roaming service according to a preferred embodiment of the present invention.

In the call flow applied to the roaming service of the present invention, the MIN information is transmitted from the inbound mobile communication terminal 100 to the CDMA mobile switching center 120 (S202). The mobile switching center 120 confirms the MIN information of the terminal and transmits the MIN information to the GSM GLR 130 in the CDMA communication service area (S204). The GSM GLR 130 confirms the inbound mobile communication terminal 100 by checking the MIN information of the inbound mobile communication terminal and transmits the IMSI information of the GSM standard corresponding to the MIN information of the inbound mobile communication terminal to the GSM home network 140, And attempts authentication request (S208).

The GSM home network 140 confirms the IMSI information and transmits the authentication vector of the GSM communication standard to the GSM GLR 130 (S210). The GSM GLR 130 transmits the authentication vector of the CDMA communication standard to the CDMA mobile switching center 120 at step S212 and transmits the authentication vector of the CDMA communication standard to the inbound mobile communication terminal 100 at step S214. The authentication vector transmitted to the inbound mobile communication terminal 100 includes the number of times that the subscriber can attempt to answer the authentication, and the number of attempts is preferably four times.

After receiving the authentication vector, the inbound mobile communication terminal 100 performs a predetermined operation using the received authentication vector, generates response information (SRES: Singed Response) for the authentication vector, and transmits it to the mobile communication switching center 120 And transmits the response information SRES to the GSM GLR 130 (S216). The GSM GLR 130 verifies the authentication vector using the authentication vector response information and requests location registration to the GSM home network 140 (S218). The GSM home network 140 performs a new location registration and notifies the GSM GLR 130 of the new location registration (S220). The GSM GLR 130 requests subscriber information and supplementary service information from the GSM home network 140 in step S222 and receives the information in step S224 to update the information table and transmits the subscriber information to the mobile switching center 120. [ The GSM GLR 130 informs the mobile switching center 120 of the normal processing result of the location registration of the inbound mobile communication terminal (S226).

Since the roaming service procedure accommodates all communication standards of each mobile communication network, it takes tens to hundreds of times longer than a millisecond, which is a time required for a location registration procedure in a typical wireless mobile communication. As a result, when a caller is moving, the quality of a call during a roaming service is degraded, and a handoff problem may occur particularly when a caller is moving between mobile switching center boundary areas.

Therefore, in order to solve such a problem, the present invention adds a process (S206) of notifying the CDMA mobile switching center 120 of the location registration normal processing result before the GSM GLR 130 requests the location registration to the GSM home network 140 So as to maintain stable call quality in the CDMA mobile communication network area. That is, the authentication and location registration procedures for receiving the actual roaming service in the GSM GLR 130 are allowed to proceed as it is, and separately, in order to maintain the call quality in the CDMA mobile communication network area, And notifies the result of the normal processing of the location registration of the terminal.

When notifying the result of the location registration normal process to the mobile switching center 120 in step S206, the GSM GLR 130 transmits the authority of the subscriber, that is, the usage right of the mobile communication terminal 100, Service) to be used. That is, if the location registration is permitted in advance as in step S206, since the processing for the call requested from the mobile communication terminal 100 can be performed, the usage right of the mobile communication terminal 100 is limited, , A step S214 and a step S216 to transmit the authentication vector and receive a response to the short message service) to the mobile communication terminal 100 using the Short Message Delivery Point-Point Protocol (SMDPP) Thereby preventing the problem of illegal copying.

The foregoing description is merely illustrative of the technical idea of the present invention, and various changes and modifications may be made by those skilled in the art without departing from the essential characteristics of the present invention. Therefore, the embodiments disclosed in the present invention are intended to illustrate rather than limit the scope of the present invention, and the scope of the technical idea of the present invention is not limited by these embodiments. The scope of protection of the present invention should be construed according to the following claims, and all technical ideas falling within the scope of the same shall be construed as falling within the scope of the present invention.

As described above, according to the present invention, it is possible to improve the roaming service quality by improving the mobility problem of the mobile communication terminal in the CDMA inbound area.

In addition, it can be applied to operators other than specific mobile communication service providers and other countries.

Claims (5)

In a roaming system, An inbound mobile communication terminal equipped with a GSM SIM (Subscriber Identity Module) card; A mobile switching center for receiving MIN (Mobile Identity Number) information from the inbound mobile communication terminal; And When receiving the MIN information from the mobile switching center, transmits a user right restriction message for changing the usage right of the inbound mobile communication terminal to the mobile switching center, and then transmits International Mobile Subscriber Identity (IMSI) information corresponding to the MIN information And transmits the authentication vector from the GSM home network to the mobile switching center. In response to the authentication vector received from the mobile switching center, To a GSM home network to request a location registration, Wherein the roaming system maintains call quality of the inbound mobile communication terminal. The method according to claim 1, The GSM GLR comprises: Wherein the inbound mobile communication terminal transmits the user right restriction message to the mobile switching center, the user right restriction message having a usage right for performing communication only with the short message service (SMS) standard. Roaming system to maintain call quality. In a method for GSM GLR roaming, A rights restriction process for transmitting a user right restriction message to the mobile switching center to change usage rights of the inbound mobile communication terminal when receiving MIN information of the inbound mobile communication terminal from the mobile switching center; An authentication requesting step of requesting authentication of the inbound mobile communication terminal by transmitting IMSI information corresponding to the MIN information to the GSM home network; An authentication vector transmission step of receiving an authentication vector from the GSM home network and transmitting the authentication vector to the mobile switching center; And A location registration request process for requesting location registration by transmitting response information for the authentication vector received from the mobile switching center to the GSM home network Wherein the call quality of the inbound mobile communication terminal is maintained. The method of claim 3, The authentication vector transmission process includes: Transmitting the authentication vector to the GSM GLR when confirming the IMSI information in the GSM home network; Storing the authentication vector and transmitting the authentication vector to the mobile switching center; Transmitting the authentication vector from the mobile switching center to the inbound mobile communication terminal; Wherein the location registration request process comprises: The inbound mobile communication terminal calculating the authentication vector to generate the response information for the authentication vector and transmitting the response information to the mobile switching center; The mobile switching center transmitting the authentication vector response information to the GSM GLR; Requesting location registration to the GSM home network using the authentication vector response information; Transferring subscriber information from the GSM home network to the GSM GLR, and forwarding the received subscriber information to the mobile switching center; And A step of notifying the mobile switching center of the result of normal processing of location registration of the inbound mobile communication terminal Wherein the call quality of the inbound mobile communication terminal is maintained. The method of claim 3, The rights restriction process may include: And transmitting the user right restriction message to the mobile switching center in which the inbound mobile communication terminal sets a use right for performing communication only in the short message service (SMS) standard. A roaming method to maintain call quality.

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