KR100691591B1 - An apparatus and method of packet service hand over for WCDMA network to CDMA 1x network using DBDM station - Google Patents

Abstract

The present invention provides a service continuity by using a mobile IP function when a subscriber using a packet switch service of a WCDMA network or a packet switch service of a CDMA network is moved to another network by using a DBM (Dual Band Dual Mode) terminal. An apparatus and method for packet handover from a WCDMA network to a CDMA network using a DBDM terminal are provided. The present invention is responsible for mobile IP in the WCDMA network and provides a packet service, and performs a gateway (Gateway) function for matching with the Internet / Intranet, the current location information of the DBDM terminal GGSN / HA that tunnels / routes the packets provided to the terminal, and AAA server that handles authentication / authority verification, packet-based charging, subscriber management and address assignment, etc. as an authentication node for mobile IP service. In addition, the CDMA 1X network can perform packet handover from the WCDMA network to the CDMA 1X network without any additional equipment, and thus, packet handover from the WCDMA network to the CDMA network using a DBDM terminal that provides continuity of packet services. Apparatus and method.

Packet handover.

Description

An apparatus and method of packet service hand over for WCDMA network to CDMA 1x network using DBDM station}

1 shows a conventional WCDMA network and a CDMA 1X network,

2 is a block diagram of an apparatus for processing packet handover from a WCDMA network to a CDMA network using a DBDM terminal according to the present invention;

3 is a flowchart illustrating an operation of processing a packet handover from a WCDMA network to a CDMA network using a DBDM terminal of the present invention.

<Description of Major Symbols in Drawing>

50: DBDM terminal 51: Node B (Node-B)

52: RNC (Radio Network Controller)

53, 58: Serving GPRS Support Node (SGSN)

54: Gateway GPRS Support Node (GGSN)

55: GPRS backbone

56: GGSN / HA (Gateway GPRS Support Node / Home Agent)

57, 74: AAA (Authentication Authorization Accounting)

60: content provider 70: BS (base station)

71: BSC (Base Station Controller) 72: MSC (mobile switching center)

73: packet switched data network (PSDN)

75: HA (Home Agent)

The present invention provides a service continuity by using a mobile IP function when a subscriber using a packet switch service of a WCDMA network or a packet switch service of a CDMA network is moved to another network by using a DBM (Dual Band Dual Mode) terminal. An apparatus and method for packet handover from a WCDMA network to a CDMA network using a DBDM terminal are provided.

In general, wideband code division multiple access (W-CDMA) is a wideband code division multiple access (CDMA) scheme for the International Mobile Communications 2000 (IMT-2000), where the International Telecommunication Union (ITU) is promoting standardization. It is a technology to make money. This scheme is a wideband code division multiple access proposed by CDG (CDMA Development Group), a CDMA digital cellular system standardization organization, and a method independently proposed by NTT and KDD in Japan.

On the other hand, code division multiple access (CDMA) is one of the next generation digital mobile communication methods, and adopts spread spectrum technology. Qualcomm, USA, proposed Code Division Multiple Access (CDMA), a bandwidth of 1.25 MHz, as a standard for digital cellular cars and mobile phones in North America. In July 1993, the American Electronics Industry Association (EIA) voluntary standard. It was established as IS-95. CDMA allows multiple users to share the same frequency band, which uses a PN code unique to the user communication channel to distinguish between users. On the transmitting side, the frequency band is spread by multiplying the voice data by a PN code whose clock frequency is several tens or more times the voice data frequency bandwidth. At the receiving side, multiplying the same PN code at the time of transmission, the bandwidth is returned to its original width and demodulated. The characteristics of CDMA are as follows. Compared to time division multiple access (TDMA) or analog frequency division multiple access (FDMA), the user channel per bandwidth can be increased by 10 to 20 times.Because the transmission frequency is wide, it is strong in frequency selective fading by multipath signals. If the same PN code is not used at the time of transmission, demodulation is not performed, thereby ensuring incompatibility. As it is a large capacity that can increase subscriber capacity than the conventional method, it is suitable for a large city, and there is a simple advantage of reducing the number of cells and frequency planning due to the wider service area. In addition, the US IDC company proposes a wideband CDMA method using the spread spectrum technology, the transmission bandwidth is 10MHz, which is much wider than CDMA.

Mobile IP is a technology for a mobile terminal using the Internet protocol. When the mobile terminal accesses a remote network from the outside, if the home agent HA registers an address obtained from the current network, the home network sends data to the terminal in the remote network. The Internet Engineering Task Force (IETF) proposed RFC 2002 to reduce the complexity of IP address management in the case of frequent department transfers or many mobile workers. The mobile IP standard consists of two parts: mobile IP agents and mobile nodes, which are responsible for the virtual routing service that routes packets to registered mobile terminals.

Hereinafter, the configuration of a conventional WCDMA network and a CDMA 1X network will be described with reference to the drawings.

1 shows a conventional WCDMA network and a CDMA 1X network.

The configuration of the 3GPP WCDMA network shown in FIG. 1 serves as a mobile communication terminal 10 capable of processing WCDMA packet services and a base station of a WCDMA network, which provides Node B (Node-B) for providing a wireless service environment ( 11 and 13 show RNCs 12 and 14 which process radio access control of the mobile communication terminal.

In addition, it provides the Internet service by connecting the RNC 12, 14 and the GPRS packet network, the SGSN (15, 16) connected to the RNC (12, 14) to handle packet subscriber control and packet call processing, and the WCDMA network. Is a communication network that is constructed to transmit and manage information at a high speed in a network to be commonly used in establishing a network, and a GPRS backbone network 17, which is a backbone network composed of FDDI or ATM backbones, an IP address allocation, the Internet, and the like. GGSNs 18 and 19 serving as gateways for packet network access, and content provider servers 35 for providing content services.

On the other hand, in the conventional 3GPP WCDMA network packet handover, when the user of the WCDMA mobile communication terminal moves to another area in the WCDMA network, the node B of the corresponding area is communicated between the SGSNs 15 and 16 to ensure the mobility of the subscriber. (11, 13), the handover between the RNC (12, 14) and SGSN (15, 16) is made, the IP address is not changed to ensure the continuity of packet service.

Therefore, the path of the GGSN (18, 19) matching the packet network, such as the Internet (Internet) also does not change, but only the traffic path between the GGSN (18, 19) and SGSN (15, 16) is changed to continue the service.

In addition, the configuration of the 3GPP2 CDMA 1x network of FIG. 1 includes a mobile communication terminal 20 capable of packet service of a CDMA 1x network, a BS 21 and 23 serving as a base station, and a BSC 22 and 24 for wireless access control of the mobile communication terminal. ), MSCs 25 and 26, which are exchanges for packet subscriber control and packet call processing functions, HA 29 for mobile IP address assignment, and PDSN (FA) for packet network access such as the Internet. (27, 28) and the AAA (30) for processing the authentication.

In case of packet handover in the 3GPP2 CDMA 1x network, when a user of the CDMA 1x mobile communication terminal 20 moves to another area and needs a handover, the MSCs 25 and 26 communicate with each other to secure the subscriber's mobility. 21, 23), the paths between BSCs 22 and 24 and PDSN (FA) 27 and 28 are replaced by the above diagrams and network nodes in the new area, but the IP addresses are not changed to ensure continuity of packet services. .

Therefore, the path of the HA 54 matching with the packet network such as the Internet is not changed, but only the traffic path between the HA 54 and the PDSN (FA) 27 and 28 is changed to ensure continuity of services.

As described above, in the case of the packet handover in the conventional WCDMA packet service network, the packet handover in the WCDMA network is processed, but the packet handover with the CDMA 1x packet service network is not defined.

On the contrary, packet handover in a CDMA 1x packet service network is possible, but packet handover with another WCDMA packet service network is not provided.

Therefore, when a WCDMA packet service network subscriber moves to a CDMA 1x packet service network, which is an area of another mobile communication network, packet handover is not provided, so service continuity cannot be guaranteed. Even in the case of moving to the WCDMA packet service network area, since packet handover is not provided, there is a problem in that service continuity cannot be guaranteed.

In addition, there is a problem in that the mobile communication terminal 10 subscribed to the conventional WCDMA packet service network and the mobile communication terminal 20 subscribed to the CDMA 1x packet service network cannot handle packet handover.

The present invention has been made to solve the above-mentioned problems, and the packet service, such as the Internet, can continue to be used by providing a packet handover service even when moving to a CDMA 1X network area while moving a packet service in a WCDMA network using a DBDM terminal. An object of the present invention is to provide an apparatus and method for packet handover from a WCDMA network to a CDMA network using a DBDM terminal.

In addition, the present invention performs a function for providing a packet service to the mobile IP to the WCDMA network, and performs a gateway (Gateway) function for matching with the Internet / Intranet, the current state of the DBDM terminal GGSN / HA which maintains location information and tunnels / routes the packet provided to the terminal, and handles authentication / authority verification, packet-based charging, subscriber management and address assignment, etc. as an authentication node for mobile IP service. Equipped with an AAA server, the CDMA 1X network can perform packet handover from the WCDMA network to the CDMA 1X network without any additional equipment so that packets from the WCDMA network to the CDMA network using a DBDM terminal providing continuity of packet services It is an object of the present invention to provide a handover apparatus and method.

The packet handover apparatus from the WCDMA network to the CDMA network using the DBDM terminal of the present invention is connected to the RNC to control the subscriber of the packet and handle the packet call, SGSN, IP address assignment and gateway for Internet / Intranet packet network access. In using a packet service to a DBDM terminal in a GPRS network constituting a WCDMA network including a GGSN and a GPRS backbone network, the GGSN is added to the GGSN to maintain location information of the DBDM terminal, tunnel, route, and route the packet. CDMA with HA that provides mobile IP service to mobile IP service assigned to DBDM terminal and AAA server that is connected to GPRS backbone network and handles mobile IP authentication, authorization verification and billing during packet handover Processing a packet handover with a 1X network.

In addition, the HA does not reassign the IP address allocated to the DBDM terminal to the DBDM terminal during packet handover to the CDMA 1x network until the use of the packet service of the DBDM terminal is terminated to maintain the packet service. It further comprises.

A packet handover method from a WCDMA network to a CDMA network using a DBDM terminal of the present invention is a DBDM terminal that uses a packet service in a WCDMA network to move to a CDMA 1x network area, and then performs a handover of a packet service from the DBDM terminal to an RNC. Step 1 of transmitting a report (Measure Report), step 2 of sending the information of the resource allocated by the BSC to the DBDM terminal in the Handover from UTRAN command message, and the DBDM terminal In step 3 of transmitting a handoff completion signal to the BSC, and receiving an Ack Order signal from a BS, which is a base station, the BSC causes the PDSN to allocate a packet service related resource and a PPP session with the DBDM terminal. Establish PPP), and in step 4 of informing the MSC that the handover is completed, and SGSN sends a request for a delete PD context to the GGSN (Delete PDP (packet data protocol) C ontext Req) to send a message indicating the end of the session due to handover and GGSN is used for the mobile IP address terminated by the handover in the CDMA 1x system in the DBDM terminal. Step 6 of managing not to be allocated, the RNC transmits a Release Release (Iu Release Complete) signal to the SGSN, the GGSN transmits a delete packet data protocol (PDP) Context Response (PDP) message to the SGSN And step 8, wherein the DBDM terminal is packet handed over from the WCDMA network to the CDMA 1x network and connected to the content provider server via the new transmission paths BS, BSC, and PDSN (FA) to continue using the packet service. Characterized in that.

In addition, in the first step of the present invention, if the RNC is a packet handover condition from the WCDMA network to the CDMA 1x system after the first step, the QoS information for the packet service is included in the reloc required message and the SGSN is transmitted. In step 9 for requesting packet handover by sending a message to the MSN, after step 9, SGSN requests an inter-system handover to the MSC, which is an exchange of the CDMA 1x network, via a RGW (Roaming Gateway); Step 11 for the service user to allocate a resource corresponding to the quality of service (QoS) used in the WCDMA network, and the BSC transmits a response to the handover to the MSC, and the MSC sends the result. 12 steps of transmitting to SGSN of WCDMA network and 13 steps of transmitting SGS information to RNC by using a reloc command and transmitting information on related resources. It characterized by hamham.

In step 3 of the present invention, the PDSN is a step 14 of transmitting an Agent Advertisement (Agent Advertisement) message to the DBDM terminal, and the DBDM terminal is a GGSN serving as a home agent (HA) via the PDSN Step 15 of sending a Mobile IP Registration Req message to the / HA; and step 16 of transmitting a signal requesting to register the mobile IP address assigned to the GGSN / HA in the PSDN, and after the step 16, the mobile IP Is registered in the HA, the BSC sends a handoff complete message to the MSC, and the MSC notifies the SGSN that the packet handover is completed and the SGSN releases the connection with the RNC. It further comprises.

Hereinafter, a packet handover method from a WCDMA network to a CDMA network using a DBDM terminal of the present invention will be described in detail with reference to the accompanying drawings.

The present invention relates to a packet service handover for providing continuity of service when a subscriber using a packet switch service or a CDMA 1X packet switch service of a WCDMA network moves to a heterogeneous system area to a DBDM terminal. The present invention relates to packet handover between heterogeneous systems that process without additional equipment and provide continuity for packet services by introducing a mobile IP function in a WCDMA system.

2 is a block diagram of an apparatus for processing packet handover from a WCDMA network to a CDMA network using a DBDM terminal of the present invention, and FIG. 3 is a packet hand from a WCDMA network to a CDMA network using a DBDM terminal of the present invention. This is a flowchart of operations that handle over.

The configuration of the 3GPP WCDMA network shown in FIG. 2 serves as a base station of a DBDM terminal 50 and a WCDMA network capable of processing a service compatible with a WCDMA packet service and a CDMA 1X network, and providing a wireless service environment. B (Node-B) 51 shows an RNC 52 that processes radio access control of a mobile communication terminal.

In addition, the RNC 52 and the GPRS packet network are connected to provide a packet service such as an Internet service, thereby providing a packet handover service between the Internet service and the CDMA 1X network.

 SGSNs 53 and 54, which are connected to the RNC 52 for packet subscriber control and packet call processing functions, and a communication network for transmitting and managing information at high speed in a network to be commonly used in establishing a WCDMA network. GPRS (general packet radio service) backbone network 55, GGSN (54, 56) serving as a gateway for packet network access such as IP address allocation and Internet, and contents service providing contents service. It consists of a provider server 35 and the like.

The present invention maintains the current position information of the DBDM terminal 50 in the GGSN provided in the GPRS packet network of the WCDMA network and the CDMA 1X network, tunnels the packet, and assigns an address to the GGSN. Adds HA (56) function to manage mobile IP address, authentication / authorization of subscriber which is authentication node for mobile IP service, packet-based charging, subscriber management and address assignment, etc. It provides an AAA (57) server for processing the packet handover service.

The gateway GPRS support node / home agent (GGSN / HA) 56 of the present invention performs a function for providing a packet service when the DBDM terminal 50 requests a packet data service, and performs an Internet / Intranet service. ), Performs a gateway function for matching with (), maintains current location information of the DBDM terminal 50, and tunnels / routes a packet provided to the terminal.

When the GGSN / HA 56 assigns an IP (Internet Protocol) address to the home agent (HA) of the DBDM terminal 50, the HA function may be performed.

The GGSN / HA performs an HA function for mobile IP services in order to guarantee the mobility of the UE in the WCDMA packet network.

In addition, the configuration of the 3GPP2 CDMA 1x network of FIG. 2 includes a DBDM terminal 50 capable of packet service of the CDMA 1x network, a BS 70 serving as a base station, a BSC 71 for radio access control of a mobile communication terminal, and a packet subscriber. MSC 72, which is an exchange in charge of control and packet call processing functions, HA 29, which is in charge of mobile IP address allocation, maintains current location information of DBDM terminal 50, and routes packets; , PDSN (FA) (27, 28) which is in charge of packet network access such as Internet and performs interworking function (IWF) with wireless network and AAA (Authentication) which handles authentication, authorization verification, charging, subscriber management, etc. Authorization Accounting) 30 and the like.

PDSN (FA) 27, 28 also provides the location of DBDM terminal 50 to HA 29.

The present invention provides a packet handover service with a CDMA 1X network by providing a GGSN / HA 56 and an AAA 57 in a GPRS packet network of a WCDMA network to handle packet handover. It is possible to handover from the WCDMA network to the CDMA 1X network and the packet handover from the CDMA 1X network to the WCDMA network when using the packet service, which eliminates the problem of interrupting the packet service even when the user moves. Provide quality service.

According to the present invention, when a subscriber receiving a packet service in a WCDMA network moves to a CDMA 1x system area, the present invention detects this in a dual band dual mode (DBDM) terminal 50 supporting WCDMA and CDMA 1x wireless technologies, and then transfers the CDMA 1x from a WCDMA system. Request a handover between systems.

The RNC 52 causes the SGSN 53 to release resources allocated for packet service and requests the DBDM terminal 50 to attempt to establish a packet call to the CDMA 1x system.

The DBDM terminal 50 requests to establish a packet call using a previously assigned mobile IP address and hands over to the CDMA 1x system to continue using the packet service using a new traffic path.

3 is a flowchart illustrating an operation of processing a packet handover from a WCDMA network to a CDMA 1x network using a DBDM terminal of the present invention.

If the DBDM terminal 50 moves to the CDMA 1x area while the DBDM terminal 50 attempts to service a packet in the WCDMA system and receives a mobile IP address from the GGSN 56, the DBDM terminal 50 moves to the CDMA 1x area. The report (Measure Report) is reported to the RNC 52 (S200).

When the packet handover condition between the WCDMA system and the CDMA 1x system is reached, the RNC 52 transmits QoS information on the packet service currently provided by the user to the SGSN 53 in a reloc required message. A packet handover is requested (S201).

The SGSN 53 makes a handover request between heterogeneous systems to the MSC 72, which is a switch of the CDMA 1x network, via a Roaming Gateway (RGW) (S202).

The CDMA 1x MSC 72 makes a hard handoff request to the BSC 71 to allow a service user to allocate a resource corresponding to a quality of service (QoS) used in the WCDMA network (S203).

The CDMA 1x BSC 71 responds to the handover to the MSC 72, and the CDMA 1x MSC 72 informs the SGSN 53 of the WCDMA network (S204, S205).

The SGSN 53 of the WCDMA network informs the RNC 52 that the CDMA 1x BSC 71 has successfully allocated a related resource corresponding to the QoS used in the WCDMA network by using a reloc command. Information is transmitted together (S206).

The RNC 52 informs the DBDM terminal 50 of the resource information allocated by the CDMA 1x BSC 71 in a Handover from UTRAN Command message (S207).

The DBDM terminal 50 notifies the CDMA 1x BSC 71 of successfully allocating CDMA 1x system related resources while transmitting CDMA 1x related null data (S208).

The DBDM terminal 50 transmits a handoff completion signal to the BSC 71 and receives an authentication command from the BS 70 (S209 and S210).

The CDMA 1x BSC 71 causes the PDSN 73 to allocate packet service related resources and establish a PPP session (Establish PPP) with the DBDM terminal 50.

In addition, the MSC 72 is notified that the handover has been completed successfully (S211).

The PDSN 73 transmits an Agent Advertisement message to the DBDM terminal 50 in order to perform a foreign agent (FA) function for performing IWF with the DBDM terminal 50 (S212).

As an authentication procedure, the DBDM terminal 50 transmits a Mobile IP Registration Req message to the GGSN / HA 56 which performs the Home Agent (HA) 56 role through the PDSN 73. FA) transmits a signal for requesting to register the mobile IP address assigned by 73 (S213), and the GGSN / HA 56 registers a mobile IP and transmits a PDSN to a mobile IP registration response. (FA) 73 is sent to the DBDM terminal 50 via (S214).

When the mobile IP is registered with the HA 56, the handoff is completed, and the traffic transmitted from the data network from the time point is transmitted from the GGSN (HA) 56 to the PDSN (FA) 73 rather than the SGSN 53.

When the mobile IP is registered with the HA 56, the BSC 71 sends a Handoff Complete message to the MSC 72, and the MSC 72 indicates that the packet handover has been successfully completed. The SGSN 53 releases the signal connection between the RNC 52 and the Iu protocol (S215 to S217).

In addition, the SGSN 53 transmits a Delete Packet Data Protocol (PDP) Context Req (Inter RAT) message to the GGSN 56 to inform the end of the session due to inter-system handover (S218). In this case, the private extension field of the message is displayed as an Inter RAT HO to indicate that the corresponding IP allocated to the DBDM terminal is using the mobile IP service in the CDMA 1x system.

The GGSN 56 manages the mobile IP address allocated to the DBDM terminal 50 where the session is terminated due to heterogeneous system handover. do.

The RNC 52 sends an Iu Release Complete signal to the SGSN 53 using the Iu protocol, and the GGSN 56 sends a Delete PDP Context Response (PDP) Context Response (PDP) message. Is transmitted to the SGSN 53.

The DBDM terminal 50 is packet handed over from the WCDMA network to the CDMA 1x network, connected to the content provider server 60 via the BS 70, the BSC 71, and the PDSN (FA) 73 and continuously packetized. Use the service.

As described above, the present invention provides a packet handover service between a WCDMA network and a CDMA 1x network using the DBDM terminal 50, and is responsible for mobile IP address allocation to a GPRS packet network of a WCDMA network, Packet handover is provided with an HA 29 for maintaining current location information of the terminal 50 and routing packets, and an AAA (Authentication Authorization Accounting) 30 for processing authentication, authorization verification, billing, subscriber management, and the like. To process

As described above, the present invention can introduce a mobile IP function to the WCDMA packet system so that even if the DBDM terminal using the packet service in the WCDMA region moves to the CDMA 1x region, the packet service can be continuously used without interruption of service.

Claims (5)

From GPRS network to DBDM terminal, which consists of WCDMA network composed of SGSN which is connected to RNC and handles packet subscriber control and packet call, GGSN which serves as gateway for IP address assignment and Internet / Intranet packet network access. In using the packet service, An HA added to the GGSN to maintain location information of the DBDM terminal, tunnel and route packets, and provide a mobile IP service at the time of movement to an IP address allocated to the DBDM terminal; DBDM terminal, comprising the AAA server connected to the GPRS backbone network to handle mobile IP authentication, authorization verification, billing, etc. during packet handover, and handles packet handover with the CDMA 1X network. Packet handover device from WCDMA network to CDMA network. The method of claim 1, The HA further includes maintaining the packet service by not reallocating the IP address allocated to the DBDM terminal until the termination of the packet service of the DBDM terminal upon packet handover to the CDMA 1x network to the DBDM terminal. Packet handover device from a WCDMA network to a CDMA network using a DBDM terminal. Moving to a CDMA 1x network area using a packet service in a WCDMA network by a DBDM terminal and transmitting a measure report for handover of the packet service from the DBDM terminal to an RNC; Transmitting, by the RNC, the resource information allocated by the BSC to a DBDM terminal in a Handover from UTRAN Command message; Transmitting, by the DBDM terminal, a handoff completion signal to the BSC and receiving an Ack Order signal from a BS which is a base station; Allowing the BSC to allocate a packet service related resource to a PDSN, establish a PPP session with the DBDM terminal, and inform the MSC that the handover is complete; A SGSN sending a Delete Packet Data Protocol (PDP) Context Req) message to the GGSN to inform the end of the session by handover; Managing the mobile IP address of the GGSN terminated by the handover so that it is not reallocated when a new packet call is requested since it is still used by the DBDM terminal in a CDMA 1x system; Sending, by the RNC, a Release Release Complete signal to an SGSN, and sending a Delete PDP Context Response (PDP) message to the SGSN by the GGSN; And the DBDM terminal is packet handed over from the WCDMA network to the CDMA 1x network and connected to the content provider server via the new transmission paths BS, BSC and PDSN (FA) to continue the packet service. A packet handover method from a WCDMA network to a CDMA network using a DBDM terminal. The method of claim 3, The first step, Step 9, when the RNC meets the packet handover condition between the CDMA 1x systems in the WCDMA network, requesting packet handover by transmitting the QoS information on the packet service to a SGSN in a reloc required message;  A step 10 of SGSN requesting an inter-system handover to an MSC which is an exchange of the CDMA 1x network through a Roaming Gateway (RGW); Step 11, wherein the MSC makes a hard handoff request to a BSC to allocate a resource corresponding to a quality of service (QoS) used by a service user in a WCDMA network; Step 12, wherein the BSC sends a response to the handover to the MSC, and the MSC sends a result to SGSN of a WCDMA network; In the WCDMA network using a DBDM terminal, the SGSN informs the RNC that a related resource corresponding to the QoS has been allocated by using a reloc command and transmits information on the related resource. Packet Handover Method to CDMA Network. The method of claim 3, The third step, Step 14, wherein the PDSN transmits an Agent Advertisement message to the DBDM terminal; Transmitting, by the DBDM terminal, a mobile IP registration req message to a GGSN / HA serving as a home agent (HA) via a PDSN; Transmitting a signal for requesting to register the mobile IP address allocated to the GGSN / HA in the PSDN; In step 17, when the mobile IP is registered with the HA, a BSC transmits a handoff complete message to the MSC; 18. The MSC notifies SGSN that the packet handover is completed and the SGSN releases the connection with the RNC. 18. The method of claim 2, wherein the MSC releases the connection with the RNC.

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