KR20050071772A - Method for hand-over in the mixed network of wcdma network and cdma network - Google Patents

Abstract

The present invention provides a handover method of a mobile communication terminal in a mobile communication network in which an asynchronous network and a synchronous network are mixed.

The present invention relates to a handover method of a dual band dual mode mobile communication terminal in a mobile communication network in which an asynchronous mobile communication system and a synchronous mobile communication system are mixed, wherein the signal sensitivity with the mobile communication terminal is less than or equal to a threshold. When a NodeB requests a handover to an asynchronous exchange, and an asynchronous exchange finds an adjacent asynchronous exchange to perform an inter-cell handover and a neighbor asynchronous exchange capable of communicating with the mobile communication terminal is found, the inter-cell handover is performed by the corresponding asynchronous exchange. If the adjacent asynchronous exchange is not found, it is determined that a handover to the synchronous mobile communication system is necessary, and a handover is requested to the synchronous exchange system, and after the connection with the synchronous mobile communication system is completed, the handover with the asynchronous mobile communication system is completed. You performed a handover procedure to disconnect All.

Accordingly, it is possible to solve the call disconnection phenomenon when handover between heterogeneous networks.

Description

Method for Handover in Mobile Networks with Asynchronous and Synchronous Networks {Method for Hand-over in the Mixed Network of WCDMA Network and CDMA Network}

The present invention relates to a handover method in a mobile communication network, and more particularly, to a handover method of a mobile communication terminal in a mobile communication network in which an asynchronous network and a synchronous network are mixed.

IMT-2000 system is divided into CDMA2000-based synchronous system and WCDMA-based asynchronous system, and was developed to solve global roaming problem between mobile communication systems. In addition, in order to support global roaming between mobile communication systems, a dual band dual mode terminal (DBDM mobile communication terminal) capable of being used in both a synchronous system and an asynchronous system has been developed. By using, different types of services can be used in each of the asynchronous system domain and the synchronous system domain.

At present, the asynchronous mobile communication system is being built around an area with a high demand for service, and its range of construction is gradually increasing. However, the construction of an asynchronous service network requires a huge investment, making it difficult to service large areas. Accordingly, the service is provided in a mixed state of the asynchronous network and the synchronous network, and when a user moves between the asynchronous mobile communication system and the synchronous mobile communication system, handover between systems is performed for interworking network for continuous service provision. It is necessary.

That is, when a subscriber of an asynchronous mobile communication system receives a service in an asynchronous network area and moves to a synchronous network area where an asynchronous service is not provided, the call is disconnected. Therefore, a handover is required. As such, when the subscriber of the asynchronous mobile communication system moves to the area of the synchronous mobile communication system where the asynchronous service is not provided, the service cost can be reduced by providing the service through the synchronous mobile communication system.

However, at the time of handover between the asynchronous mobile communication system and the synchronous mobile communication system, the handover is performed by stopping communication with the mobile communication system currently connected and connecting with another mobile communication system. It takes a lot of over time (several seconds), and thus there is a disadvantage in that the quality of service is degraded due to disconnection of the call for a short time.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and there is a technical problem to provide a handover method that can prevent a communication disconnection phenomenon during handover between an asynchronous mobile communication system and a synchronous mobile communication system.

According to the present invention, in a mobile communication network in which an asynchronous mobile communication system and a synchronous mobile communication system are mixed, a signal sensitivity of a dual band dual mode mobile communication terminal with a base station (node B) connected to each other along a position movement is less than or equal to a specified threshold. A method for performing a handover when the signal is lower than the threshold value, and when the signal sensitivity with the mobile communication terminal is less than or equal to the threshold, the asynchronous exchange can search for an adjacent asynchronous exchange to perform inter-cell handover and communicate with the mobile communication terminal. Is detected, Node B of the asynchronous mobile communication system requests a handover to the asynchronous exchange and performs cell-to-cell handover to the asynchronous exchange. If a neighbor asynchronous exchange is not detected, a handover to the synchronous mobile communication system is required. If so, request a handover to the synchronous exchange, After the connection to the group the mobile communication system is completed and performs a handover process for releasing the connection with the asynchronous mobile communication system.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a block diagram of a mobile communication network to which the present invention is applied.

The mobile communication terminal 10 applied to the present invention is a dual band dual mode (hereinafter, referred to as 'DBDM') mobile communication terminal, which is a form capable of simultaneously providing an asynchronous mobile communication service and a synchronous mobile communication service. Reference will be made to 2 below. The DBDM mobile communication terminal 10 may wirelessly connect to the asynchronous mobile communication system 20 and the synchronous mobile communication system 30 to use voice and data services.

The asynchronous mobile communication system 20 is a wireless network controller (Node B / RNC, 210) for controlling Node B and Node B as a base station for wireless section communication with the mobile communication terminal 10, wireless network controller 210 Short service center connected with the asynchronous exchange (MSC, 220), the asynchronous exchange 220 and the No.7 common signal network 230 to perform a call exchange for providing a service to the mobile communication terminal (10) (SMSC, 240), the intelligent network controller (SCP, 250) and home location register (HLR, 260), the wireless network controller 210 and the GPRS (General Packet Radio Service) network 280 is connected to the mobile communication terminal (10) Is connected via a Serving GPRS Support Node (SGSN) 270, a SGSN 104, and a General Packet Radio Service (GPRS) network 280, which monitors the location and performs security and access control functions. A Gateway GPRS Support Node (GGSN) 290 connected to support interworking with external packets is included.

In addition, the synchronous mobile communication system 30 is connected to the mobile communication terminal 10 and the base station controller (BTS / BSC, 310) for controlling the base station and the base station for supporting the wireless section communication, and connected to one or more base station controller to perform a call exchange Short-term service center (SMSC, 340), intelligent network controller (SCP, 350) and home location register (HLR) connected through an exchange (MSC) 320, an exchange 320, and a No. 7 common signaling network 330 to perform 360, a data core network for supporting a connection between a packet data service node (PDSN, 370) and a packet data service node 370 and the Internet 40 to be connected to a base station controller to provide a packet data service to a subscriber ( DCN, 380 is configured.

The interworking unit (IWF) 50, which performs a mutual conversion of the handover related MAP between the asynchronous mobile communication system 20 and the exchanges 220 and 320 of the synchronous mobile communication system 30, has a No. 7 common signal. It is connected to each other via the network (230, 330) to transmit and receive information necessary for handover, etc. of the mobile communication terminal (10).

In such a network configuration, the mobile communication terminal 10 located in the area of the asynchronous mobile communication system 20 periodically measures and reports the signal strength with the Node B 210 and specifies the signal strength with the Node B 210. When the threshold value falls below the RNC 210, the RNC 210 requests a handover to the asynchronous exchange 220, and the asynchronous exchange 220 is a handover between the asynchronous mobile communication system 20 or the inter-system handover to the synchronous mobile communication system 30. It is determined whether the handover.

In case of a handover between asynchronous systems, the asynchronous exchanger 220 requests a handover to the asynchronous exchanger 220, and in the case of a handover to the synchronous mobile communication system 30, the synchronous exchanger through the interworking unit 50. Request a handover through the 320 and the map (MAP) interworking, in this case, to the synchronous exchange 320 serving the area where the mobile communication terminal 10 is located, and transmits a message that can communicate with the synchronous exchange 320 shall. The interworking unit 50 that processes the message conversion between the asynchronous network and the synchronous network may be performed by the asynchronous exchanger 220, the synchronous exchange 320, or by introducing a separate dedicated system.

In addition, a handover trunk may be defined in advance between the asynchronous exchanger 220 and the synchronous exchange 320 as a passage for transmitting a message for performing a handover, or a regular trunk may be allocated at any time during handover. A detailed handover process will be described later.

2 is a structural diagram of a mobile communication terminal applied to the present invention.

As shown, the DBDM mobile communication terminal 10 applied to the present invention includes an antenna 100, a module 110 for a synchronous mobile communication service, a module 120 and a common module 130 for an asynchronous mobile communication service. It is configured to include.

The antenna 100 may simultaneously process a frequency band for a synchronous mobile communication service and a frequency band for an asynchronous mobile communication service.

The synchronization module 110 includes a duplexer 111 that operates as a band pass filter for separating and processing respective frequencies, a synchronous wireless transceiver 112 for separating transmission and reception radio waves into a predetermined frequency band, and a wireless section with a synchronous mobile communication system. The asynchronous module 120 includes a synchronous modem unit 113 for processing a protocol, and the asynchronous module 120 divides each frequency into a duplexer 121 that operates as a band pass filter, and asynchronous radios for separating transmission and reception radio waves into predetermined frequency bands. It includes a transmitting and receiving unit 122 and an asynchronous modem unit 123 for processing a wireless section protocol with the asynchronous mobile communication system.

The common module 130 includes an application processor, a memory, an input / output unit, other application processing units, etc. that operate as a central processing unit for controlling the synchronous modem unit 113 and the asynchronous modem unit 123 and perform multimedia functions.

In addition, the DBDM mobile communication terminal 10 is equipped with software for user interface, additional service, mobility management, access / session control, resource control, and protocol processing, so that a user can use various application services and perform handover. Performs protocol conversion according to the mobile communication system.

3 is a flowchart illustrating a handover concept in a mobile communication network in which an asynchronous network and a synchronous network are mixed.

In one mobile communication system, handover (or handoff) refers to a technology that enables a user to communicate without disconnection when a mobile communication terminal moves from one cell to another cell of the mobile communication system.

The present invention provides a handover method of a DBDM mobile communication terminal in a network in which a synchronous mobile communication system and an asynchronous mobile communication system are mixed, where a mobile communication terminal moves from a synchronous area to an asynchronous area, and a mobile communication terminal in an asynchronous area. A handover can be considered when moving to the synchronization area.

When the mobile communication terminal located in the asynchronous region moves to the synchronous region, the mobile communication terminal periodically measures the signal strength with the node B (S10), and the RNC 210 checks whether the signal sensitivity is below a specified threshold value (S10). S20). As the mobile communication terminal moves, the magnitude of the pilot signal received from the Node B of the asynchronous mobile communication system currently being communicated to the mobile communication terminal is gradually attenuated, and when the signal sensitivity falls below a specified threshold, the RNC 220 It is determined that the over event has occurred, and requests a handover between the exchanges to the asynchronous exchange currently in communication to perform the appropriate handover procedure (S30). At this time, the RNC should request a handover even if there is no NodeB having an appropriate signal strength capable of handover. At the same time, the mobile communication terminal must start the preparation procedure so that the synchronization modem unit 113 can be synchronized with the synchronization BTS 310.

The asynchronous exchange checks whether there is an adjacent asynchronous exchange to be handed over (S40), and if there is an asynchronous exchange, performs a handover procedure to the corresponding exchange (S50). On the other hand, if there is no adjacent asynchronous exchange in step S40, it is determined that handover to the synchronous network is required, and requests a handover to the synchronous exchange (S60), and the handover procedure to the synchronous network is performed (S70). ).

4 is a flowchart illustrating a handover method in an asynchronous network, and illustrates a case where a handover trunk connection is not required. For convenience of explanation, the node B and the radio network controller which are already connected will be represented by RNS-A, and the node B and the radio network controller to be handed over will be represented by RNS-B, respectively.

As the mobile communication terminal located in the asynchronous mobile communication system moves its position and the signal sensitivity with the previously connected RNS-A is lowered below the specified threshold, the RNS-A reports that the handover to the exchange-A is necessary. (A-RELOC-REQUIRED) (S501).

Accordingly, exchange-A requests a handover to a neighbor exchange-B to handover using a map message (S502) (MAP-Prep-Handover req.), And exchange-B requests handover to RNS-B. (S503) (A-RELOC-REQUEST). Accordingly, the RNS-B transmits a response signal for the handover request message (A-RELOC-REQUEST) to the exchange-B (S504) (A-RELOC-REQUEST-ACK), and the exchange-B also switches to the exchange-A. A response message for the handover request (MAP-Prep-Handover req.) Is transmitted (S505) (MAP-Prep-Handover resp.).

Here, the handover request message (MAP-Prep-Handover req.) That the exchange-A transmits to the exchange-B includes all the information required by the exchange-B for the radio channel assignment. The information for is included in the handover request message (A-RELOC-REQUEST) transmitted by the exchange-B to the RNS-B and transmitted to the RNS-B.

Subsequently, the exchange-A instructs handover to the RNS-A (S506) (A-RELOC-COMMAND), and subsequently, the RNS-B transmits a response signal received from the mobile communication terminal to the exchange-B (S507). (A-RELOC-DETECT). The exchange-B receiving the response signal of the mobile communication terminal requests an access signal from the exchange-A (S508) (MAP-Process-Access-Sig req.). The access signal includes an invoke ID, an application protocol data unit (APDU), and selected radio resource information. The exchange-A transmits such information at the request of the exchange-B.

Subsequently, the exchange-B that has reported that the handover is completed from the RNS-B (S509) (A-RELOC-COMPLETE) requests a message indicating that the connection with the RNS-A is terminated to the exchange-A (S510) (MAP- Send-End-Signal req.). This message indicates that the connection between the exchange-A and the mobile communication terminal is terminated. The exchange-A releases the connection with the RNS-A (S511) (A-CLR-CMD / COM) and indicates that the connection has been released. Notify B (S512) (MAP-Send-End-Signal resp.).

By this procedure, a handover is made from the previously exchanged switch-A to the new switch-B, and when the handover is completed, the connection with the switch-A is terminated.

5 is a flowchart illustrating a handover method between an asynchronous network and a synchronous network according to the present invention.

As the mobile communication terminal located in the area of the asynchronous mobile communication system moves its position and the signal sensitivity with the previously connected Node B is lowered below the specified threshold value, the RNC performs a handover to the asynchronous exchange including the neighbor Node B details. (A601) (A-RELOC-REQUIRED), the asynchronous exchange determines that a handover to a neighboring asynchronous exchange has occurred if there is an appropriate neighbor node B in the same or adjacent asynchronous exchange and handovers in the asynchronous mobile system network. To process If the neighboring asynchronous exchange does not exist as a result of the search, it is determined that handover to the synchronous mobile communication system is necessary, the neighboring synchronous exchange is searched for, and a handover is requested to the IWF (S602) (MAP-Prep-Handover req.).

Accordingly, the IWF requests to perform a handover to the synchronous exchange (S603) (MAP-FacilitiesDirective2 inv), and the synchronous exchange transmits a response signal thereto (S604) (MAP-FacilitiesDirective2 RR). Here, the handover performance request message (MAP-FacilitiesDirective2 inv) transmitted by the IWF to the synchronous exchange is a message used by the serving exchange (asynchronous exchange) in the handover procedure, and the target exchange exchange (synchronous exchange) that receives it receives the handover. Initialization is performed to perform, and a response signal (MAP-FacilitiesDirective2 RR) is transmitted.

In addition, the asynchronous exchange must request a handover by using a message that can communicate with the synchronous exchange. Such message conversion between the asynchronous network and the synchronous network may be performed by the asynchronous exchange, by the synchronous exchange, or by introducing a dedicated converter. Can be. In addition, a handover trunk may be defined in advance between the asynchronous exchange and the synchronous exchange as a path for transmitting a message for performing a handover, or a regular trunk may be allocated at any time during handover.

After receiving the handover request message, the synchronous exchange instructs the base station controller to perform the handover (S605), and the base station controller transmits the frame through the omnidirectional channel to the mobile communication terminal (S606). In addition, the IWF transmits a response message for the handover request (MAP-Prep-Handover req.) To the asynchronous exchange (S607), and receives the asynchronous exchange instructing the RNC to perform the handover (S608) ( A-RELOC-AOMMAND).

Next, the RNC instructs handover to the mobile communication terminal (S609) so that the mobile communication terminal drives the synchronous modem unit. This is a process in which the mobile communication terminal prepares a connection with the synchronous mobile communication system in advance because it takes about 10 seconds to drive the synchronous modem unit.

The mobile communication terminal receiving the omni-directional frame and instructing handover transmits the frame to the BSC through the reverse channel (S610), reports that the handover is completed (S611), and the received BSC receives the handover to the synchronous exchange. Report completion (S612) (HandOff Complete). Receiving that the handover is complete, the synchronous exchange reports this to the IWF (S613) (MobileOnChannel). The handover complete message (MobileOnChannel) sent by the synchronous exchange to the IWF is used by the target exchange (synchronous exchange). This message indicates that the target exchange has successfully performed the handover request system (asynchronous mobile communication system). Report).

As such, after the handover is successfully performed to the synchronous mobile communication system, the IWF transmits an access signal request message to the asynchronous exchange (S614) (MAP-Process-Access-Sig req.), And then continues to connect with the RNC. Request to release (S615) (MAP-Send-End-Signal req.). Here, the access signal includes an invoke ID, an application protocol data unit (APDU), selected radio resource information, and the like, and the asynchronous exchange transmits such information in response to a request of the synchronous exchange. In addition, the connection release request message (MAP-Send-End-Signal req.) Is a message indicating that the connection between the asynchronous exchange and the mobile communication terminal is terminated, and the asynchronous exchange releases the connection with the RNC according to this message (S616) ( A-CLR-CMD / COM).

Thereafter, the asynchronous exchange reports to the IWF that the connection with the RNC has been released (S617) (MAP-Send-End-Signal Resp.).

As described above, when the handover from the asynchronous mobile communication system to the synchronous mobile communication system is completed, the connection with the asynchronous mobile communication system is terminated and thus the fast handover procedure can be performed without disconnection.

The present invention described above, those skilled in the art will understand that the present invention can be implemented in other specific forms without changing the technical spirit or essential features. Therefore, the above-described embodiments are to be understood as illustrative in all respects and not as restrictive. The scope of the present invention is shown by the following claims rather than the detailed description, and all changes or modifications derived from the meaning and scope of the claims and their equivalents should be construed as being included in the scope of the present invention. do.

According to the present invention described above, in a mobile communication network in which an asynchronous mobile communication system and a synchronous mobile communication system are mixed, a handover of a dual band dual mode mobile communication terminal can be performed while maintaining a connection with a mobile communication system that is being connected. After the connection with the mobile communication system is completed, the connection with the mobile communication system which is already connected can be terminated to prevent a call disconnection phenomenon during handover, thereby improving the quality of service.

1 is a configuration diagram of a mobile communication network to which the present invention is applied;

2 is a structural diagram of a mobile communication terminal applied to the present invention;

3 is a flowchart illustrating a handover concept in a mobile communication network in which an asynchronous network and a synchronous network are mixed;

4 is a flowchart illustrating a handover method in an asynchronous network;

5 is a flowchart illustrating a handover method between an asynchronous network and a synchronous network according to the present invention.

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

10: DBDM mobile communication terminal 20: asynchronous mobile communication system

30: synchronous mobile communication system 40: Internet

50: mutual interlocking unit 100: antenna

110: synchronous module 120: asynchronous module

111, 121: duplexer 112: synchronous radio transceiver

113: synchronous modem unit 122: asynchronous wireless transceiver

123: asynchronous modem unit 130: common module

210: Node B / wireless network controller 220: asynchronous switch

230, 330: No.7 common signal network 240, 340: Short service center

250, 350: intelligent network controller 260, 360: home location register

270: SGSN 280: GPRS network

290: GGSN 310: base station / base station controller

320: switch 370: packet data service node

380 data core network

Claims (6)

In a mobile communication network in which an asynchronous mobile communication system and a synchronous mobile communication system are mixed, a handover method of a dual band dual mode mobile communication terminal capable of communicating with the asynchronous mobile communication system and the synchronous mobile communication system, Monitoring signal sensitivity between the mobile communication terminal and the NodeB of the asynchronous mobile communication system, and checking whether the signal sensitivity is equal to or less than a specified threshold; Requesting handover by the Node B to an exchange of the asynchronous mobile communication system when the signal sensitivity falls below a specified threshold value; Checking, by the exchange of the asynchronous mobile communication system, whether there is another asynchronous exchange capable of communicating with the mobile communication terminal; Performing a handover procedure to the other asynchronous exchange when the other asynchronous exchange exists as a result of the checking; If there is no other asynchronous exchange as a result of the check, it is determined that handover to the synchronous mobile communication system is necessary, and a handover procedure is performed for requesting handover to a synchronous exchange and instructing handover to the mobile communication terminal. Doing; And Performing a handover procedure of releasing a connection with the asynchronous mobile communication system after the connection between the mobile communication terminal and the synchronous mobile communication system is completed; Handover method comprising a. The method of claim 1, The asynchronous exchange and the synchronous exchange are interconnected by an interworking unit, the procedure for performing a handover to the synchronous network, The asynchronous exchange requesting a handover to the interworking unit; Transmitting, by the interworking unit, a message requesting to perform a handover to the synchronous exchange, and receiving a response signal from the synchronous exchange; Instructing the synchronous exchange receiving the handover execution request message to perform a handover to a base station controller of a synchronous mobile communication system, wherein the base station controller transmits a frame to the mobile communication terminal through an omnidirectional channel; Sending, by the interworking unit, a response message for a handover request to the asynchronous exchange; Instructing the asynchronous exchange receiving the response message to the handover request to perform a handover to a wireless network controller of an asynchronous mobile communication system, and the wireless network controller instructing a handover to the mobile communication terminal; Transmitting, by the base station controller, a handover complete message to the synchronization switch as the mobile communication terminal transmits a frame to the base station controller through a reverse channel and transmits a handover complete message; The synchronization exchange receiving the handover complete message, reporting that the handover is completed to the mutual interworking unit; Sending, by the interworking unit, an access signal request message to the asynchronous exchange; Requesting the mutual interworking unit to disconnect the wireless network controller from the asynchronous exchange; And Releasing the connection between the asynchronous modem unit and the NodeB, and transmitting a connection release result to the interworking unit; Handover method comprising a. The method of claim 2, Before the interworking unit transmits a handover execution request message to the synchronous exchange and receives a response signal thereto, the synchronous exchange performs initialization for handover. The method of claim 2, Message conversion for message transmission and reception between the asynchronous exchange and the synchronous exchange through the interworking unit is performed by installing a dedicated converter between the asynchronous exchange, the synchronous exchange, or the asynchronous exchange and the synchronous exchange. The method of claim 2, The message between the asynchronous exchange and the synchronous exchange through the interworking unit is transmitted and received through a handover trunk, or a regular trunk is assigned to transmit and receive at any time. The method of claim 2, The access signal includes an invoke ID, an application protocol data unit (APDU), and selected radio resource information.