KR20040043218A - Method For Handoff Between Mobile Communication Systems - Google Patents

Abstract

PURPOSE: A handoff method is provided to allow a hybrid access terminal(HAT) to be provided with the same packet data service before and after handoff, while reducing system loads. CONSTITUTION: A handoff method comprises a step(S301,S302) of permitting a first mobile communication system to monitor the overhead channel of a second mobile communication system and collect and manage service data while maintaining an active data session; a step(S304,S305,S306) of judging whether the second mobile communication system and terminal support the data service performed prior to handoff, in accordance with the service data; and a step(S309,S316) of requesting a call setting if the data service is supported, and providing a data service for the call by performing handoff.

Description

Method for Handoff Between Mobile Communication Systems

The present invention relates to a handoff method between mobile communication systems, and more particularly, to a handoff between a high rate packet data (HRPD) system and a code division multiple access-2000 (CDMA2000) system having a difference in supportable data service rates. The present invention relates to a method for handoff between mobile communication systems to guarantee the same packet data service before and after handoff from an HRPD system to a CDMA2000 system.

In general, HRPD is a new packet wireless data transmission technology developed by Qualcomm using CDMA technology. It is a high-speed packet data method capable of providing a transmission speed of up to 2.4 Mbps in forward and 307.2 kbps in reverse. Also known as Rate) or 1xEV-DO (1xEVolution Data Only). The mobile communication system to which the HRPD method is applied is called an HRPD system.

In addition, CDMA is a next-generation digital mobile communication system that adopts spread spectrum technology. Qualcomm is a standard division of North American digital cellular cars and mobile phones. It is a code division multiple access method with a bandwidth of 1.25 MHz. CDMA2000 is based on the IS (Interim Standard) -2000. The mobile communication system to which the CDMA2000 method is applied is called a CDMA2000 system.

The HRPD system uses 1xEV-DO, which is a dedicated protocol for packet data transmission that is completely different from the IS-2000 wireless protocol used by the CDMA2000 system, and is separate from the base station (BS: Base Station) of the corresponding CDMA2000 system. An access network (AN) is required, but the rest of the system and network components are commonly used with the CDMA2000 system.

As the HRPD system and the CDMA2000 system coexist, a handoff is required between both systems. Hereinafter, a handoff method from a general HRPD system to a CDMA2000 system will be described with reference to FIG. 1.

1 is a flowchart schematically illustrating a handoff procedure from a general HRPD system to a CDMA2000 system.

HRPD system 1 is composed of Hybrid Access Terminal (HAT) 3, Access Network (AN) 4, Packet Control Function (PCF) 6 and Packet Data Service Node (PDSN) 7, and CDMA2000 The system 2 consists of a HAT 3, a base station (BS) 4, a PCF 6, and a PDSN 7, wherein the HAT 3, PCF 6, and PDSN 7 are both systems. Commonly used.

Basically, in the HRPD Active Data Session, the handoff from the HRPD system 1 to the CDMA2000 system 2 performs a Dormant handoff according to IS-878.

The video on demand (VOD) or fixed data rate service that the HAT 3 requires a specific or fixed data rate from the HRPD system 1 or high-speed data not supported by the CDMA2000 system 2. When receiving a packet data service requiring transmission, the corresponding HAT 3 is in the HRPD active data session state in the HRPD system 1 (S101) and hands off to the CDMA2000 system 2.

The HAT 3 monitors an overhead channel of the CDMA2000 system 2 (S102), and moves from the HRPD service area to the CDMA2000 service area (S103), which belongs to the HRPD system 1. Data transmission to the AN 5 is stopped (S104).

Accordingly, the AN 5 transmits a disconnect message (Disconnect) to the PDSN (7) (S105), and receives a disconnect response message (Disconnect Ack) from the corresponding PDSN (7) (S106).

The HAT 3 then transitions to the dormant state in the HRPD active data session (S107).

At this time, the HAT 3 makes a call setup request to the CDMA2000 system 2 and the CDMA2000 system 2 performs handoff by setting up a data call by allocating radio resources and negotiating service options (S108). . That is, the HAT 3 receives a specific or fixed data service and then negotiates a service option at a service rate that the HAT 3 can support and the CDMA2000 system 2 can support and allocates radio resources.

Accordingly, the BS 4 belonging to the CDMA2000 system 2 transmits a setup message to the PCF 6 (S109), and receives a connection message (Connect) from the corresponding PCF 6 (S110). Set) (S111).

Accordingly, the HAT 3 is in the CDMA2000 Active Data Session state (CDMA2000 Active Data Session) in the CDMA2000 system 2 (S112).

However, at this time, the data service before the handoff cannot be provided after the handoff due to the difference in support speed between the two systems.

The AN 5 also transmits a disconnect message to the PDSN 7 after S105 and S106 (S113), and receives a disconnect response message from the corresponding PDSN 7 (S114). Thus, before and after handoff, data service is suspended and placed in an airdrop state.

Therefore, when the HRPD system and the CDMA2000 system coexist, when handing off from the HRPD system to the CDMA2000 system, the HAT cannot receive the packet data service before the handoff after the handoff due to the difference between the data service rates that both systems can support. As a result, the CDMA2000 system has a problem of unnecessarily performing radio resource allocation and service option negotiation for a service which is lost or unsatisfactory.

SUMMARY OF THE INVENTION In order to solve the above problems, an object of the present invention is to ensure that the HAT is guaranteed the same packet data service before and after handoff from the HRPD system to the CDMA2000 system, which has a difference in supportable data service rates.

Another object of the present invention is to reduce the system load by preventing the CDMA2000 system from performing unnecessary radio resource allocation and service option negotiation.

1 is a flow diagram schematically illustrating a handoff procedure from a typical HRPD system to a CDMA2000 system.

2 is a diagram showing the configuration of a mobile communication system to which the present invention consisting of an HRPD system and a CDMA2000 system is applied.

3 is a flowchart illustrating a method for handoff between mobile communication systems from an HRPD system to a CDMA2000 system according to an embodiment of the present invention.

FIG. 4 is a flowchart schematically showing a handoff procedure between mobile communication systems when the HAT manages service data information in FIG.

5 is a flowchart illustrating a method for handoff between mobile communication systems from an HRPD system to a CDMA2000 system according to another embodiment of the present invention.

FIG. 6 is a flowchart schematically showing a handoff procedure between mobile communication systems when the PDSN manages service data information in FIG. 5; FIG.

Explanation of symbols on the main parts of the drawings

11: HRPD system 12: CDMA2000 system

13: HAT 14: BS

15: AN 16: PCF

17: PDSN

In order to solve the above-mentioned object, the handoff method between mobile communication systems of the present invention in the case of handoff from the first mobile communication system to another type of second mobile communication system, in the first mobile communication system Collecting and managing service data information by monitoring an overhead channel of the second mobile communication system while maintaining an active data session state; Determining whether the second mobile communication system and the terminal can support a data service before handoff based on the service data information; If a data service before the handoff can be supported, the method includes requesting call setup and performing a handoff to provide a data service for the call.

When the data service before the handoff cannot be supported, status information is displayed on the terminal without requiring call setup, and the service data information is collected and managed by the terminal.

In addition, the handoff method between mobile communication systems of the present invention is a system for maintaining an active data session in the first mobile communication system when handing off from a first mobile communication system to a second type of second mobile communication system. Monitoring and collecting and managing service data information; Determining whether the second mobile communication system and the terminal can support a data service before handoff based on the service data information; If a data service before the handoff can be supported, the method includes requesting call setup and performing a handoff to provide a data service for the call.

When the data service before the handoff cannot be supported, status information is displayed on the terminal without requiring call setup, and the service data information is collected and managed by a PDSN.

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

First, a configuration of a mobile communication system to which the present invention is applied will be described with reference to FIG. 2.

2 is a diagram illustrating a configuration of a mobile communication system to which the present invention consisting of an HRPD system and a CDMA2000 system is applied.

The mobile communication system to which the present invention is applied comprises an HRPD system 11 and a CDMA2000 system 12, wherein the HRPD system 11 includes a HAT 13, an AN 15, a PCF 16, and a PDSN 17. The HAT 13 includes a data rate of a specific data service, a mobile communication system type supporting the data rate, and service data information indicating a service state of a current active data session. 15) provides an interface between the HAT 13 and a packet data network to a base station, the PCF 16 is interworked with the PDSN 17 to provide data services, and the PDSN 17 is The HAT 13 manages the service data information and provides the PCF 16 and an RP interface (RP Interface: The Interface between the Radio Network (specifically the PCF (16)) and The PDSN (17)). PPP connection with the HAT 13 (Point It is a node that provides the HAT 13 to receive the Internet service by providing a -to-Point Protocol.

In addition, the CDMA2000 system 12 includes a HAT 13, a BS 14, a PCF 16, and a PDSN 17. The HAT 13, the PCF 16, and the PDSN 17 include: Since it is commonly used in the HRPD system 11 and the CDMA2000 system 12, a description thereof will be omitted, and the BS 14 is a base station for communicating with the HAT 13 or with a relay of a mobile relay station. A station established on land and not moving.

Hereinafter, with reference to FIG. 3 and FIG. 4, the mobile communication system hand from the HRPD system 11 to the CDMA2000 system 12 when the HAT 13 manages service data information according to an embodiment of the present invention. The off method is explained.

FIG. 3 is a flowchart illustrating a handoff method between mobile communication systems from an HRPD system to a CDMA2000 system according to an embodiment of the present invention. FIG. 4 is an inter-mobile communication system when the HAT manages service data information in FIG. 3. A flowchart schematically illustrating the handoff procedure.

Basically, the handoff from the HRPD system 11 to the CDMA2000 system 12 during the HRPD active data session performs the doment handoff according to IS-878.

First, when the HAT 13 is receiving a packet data service requiring a specific or fixed data rate from the HRPD system 11, the HAT 13 maintains an HRPD active data session state in the HRPD system 11 ( S301). At this time, when the HAT 13 moves from the HRPD service area to the CDMA2000 service area, the HAT 13 is in an HRPD active data session state and hands off to the CDMA2000 system 12.

The HAT 13 monitors an overhead channel of the CDMA2000 system 12 while maintaining an active data session from the HRPD system 11 to collect and manage service data information (S302). In this case, the service data information includes information about whether the HAT 13 was receiving a specific or fixed rate data service from the HRPD system 12 before the handoff.

Then, when the HAT 13 moves from the HRPD service area to the CDMA2000 service area (S303), the HAT 13 stops data transmission to the AN 15 belonging to the HRPD system 11 ( S304).

The HAT 13 then transitions to the dormant state in the HRPD active data session (S305).

Accordingly, the HAT 13 is based on the service data information managed by the CDMA2000 system 12 and the HAT after the handoff with a specific or fixed data rate of the data service provided from the HRPD system 11 before the handoff. It is determined whether the corresponding CDMA2000 system 12 and the HAT 13 can support the data service before the handoff, in comparison with the data rate that can be supported in (13) (S306).

At this time, when the determination result (S306), the CDMA2000 system 12 and the HAT 13 cannot support the data service before the handoff, the HAT 13 resumes the data service that was in service before the handoff. Call setting for the call is not required of the CDMA2000 system 12 (S307). In this case, the HAT 13 may display the corresponding state information, that is, the reason for not setting a call and a menu for selecting whether to set the call.

Thereafter, when the HAT 13 is in the dormant state and reaches a dormant timer timeout, the HAT 13 releases the HRPD session if it is in an HRPD service area (S308). Release the HRPD session when not in service area. Therefore, unnecessary radio resource allocation and service option negotiation in the CDMA2000 system 12 can be prevented in advance.

On the other hand, when the determination result (S306), the CDMA2000 system 12 and the HAT 13 can support the data service before the handoff, the HAT 13 is to service the data service that was in service before the handoff Call setup for resumption is requested to the CDMA2000 system 12 (S309).

As shown in FIG. 4, the HAT 13 transmits the managed service data information to the CDMA2000 system 12 in a first information transfer message (S310). Here, one bit of the first information transmission message is used to inform the CDMA2000 system 12 of the specific or fixed data rate.

Accordingly, the CDMA2000 system 12 receives the first information transmission message, performs radio resource allocation and service option negotiation, and establishes a data call (S311).

The BS 14 of the CDMA2000 system 12 transmits a setup message to the PCF 16 (S312), receives a connection message from the PCF 16 (S313), and sets up a setup. (S314).

Accordingly, the HAT 13 maintains a CDMA2000 active data session state (CDMA2000 Active Data Session) in the CDMA2000 system 12 (S315).

Accordingly, the CDMA2000 system 12 provides a specific or fixed rate data service for the call to the HAT 13 by using the first information transmission message (S316). Of course, when the CDMA2000 system 12 receives a NAK (Negative Acknowledgement) from the HAT 13, the CDMA2000 system 12 needs to go through an additional allocation / retrieval process of radio resources. The HAT 13 receives the specific or fixed rate data service. Thus, it is possible to provide a specific or fixed rate data service regardless of NAK.

Next, the mobile communication system from the HRPD system 11 to the CDMA2000 system 12 when the PDSN 17 manages service data information according to another embodiment of the present invention with reference to FIGS. 5 and 6. The inter-handoff method is described.

FIG. 5 is a flowchart illustrating a handoff method between mobile communication systems from an HRPD system to a CDMA2000 system according to another embodiment of the present invention. FIG. 6 is a mobile communication system when a PDSN manages service data information in FIG. 5. Is a flowchart schematically illustrating an inter-handoff procedure.

Basically, the handoff from the HRPD system 11 to the CDMA2000 system 12 during the HRPD active data session performs the doment handoff according to IS-878.

First, when the HAT 13 is receiving a packet data service requiring a specific or fixed data rate from the HRPD system 11, the HAT 13 maintains an HRPD active data session state in the HRPD system 11 ( S501). At this time, when the HAT 13 moves from the HRPD service area to the CDMA2000 service area, the HAT 13 is in an HRPD active data session state and hands off to the CDMA2000 system 12.

If both the HRPD system 11 and the CDMA2000 system 12 exist in the same PDSN 17, the corresponding PDSN 17 monitors the system to collect and manage service data information (S502). In this case, the service data information includes information about whether the HAT 13 was receiving a specific or fixed rate data service from the HRPD system 12 before the handoff.

Then, when the HAT 13 moves from the HRPD service area to the CDMA2000 service area (S503), the HAT 13 stops data transmission to the AN 15 belonging to the HRPD system 11 ( S504).

The HAT 13 then transitions to the dormant state in the HRPD active data session (S505).

As shown in FIG. 6, the PDSN 17 carries the service data information managed in the second information transmission message and transmits the service data information to the CDMA2000 system 12 through the PCF 16 (S506). Here, the CDMA2000 system 12 is informed whether a specific or fixed data rate is used by using a reserved field of the second information transmission messages A11 and A9.

Accordingly, the BS 14 belonging to the CDMA2000 system 12 receives the second information transmission message and before the HAT 13 hands off based on the service data information included in the second information transmission message. The CDMA2000 system 12 and the HAT 13 are compared with a specific or fixed data rate of the data service provided by the HRPD system 11 and a data rate that can be supported by the CDMA2000 system 12 and the HAT 13 after handoff. ) May determine whether to support the data service before the handoff (S507).

At this time, when the determination result (S507), the CDMA2000 system 12 and the HAT 13 can not support the data service before the handoff, the BS 14 sends a service unsupported message to the corresponding HAT 13 To transmit (S508). In this case, the service non-support message is a message indicating that the data service before handoff cannot be supported.

Accordingly, the HAT 13 does not request the CDMA2000 system 12 to set up a call for resuming the data service which was in service before the handoff by receiving the service unsupported message (S509). In this case, the HAT 13 may display the corresponding state information, that is, the reason for not setting a call and a menu for selecting whether to set the call.

Thereafter, the HAT 13 stays in the dormant state and when the dormant timer times out, recovers the HRPD session when in the HRPD service area (S510), and if the HRPD is not in the HRPD service area. Release the session. Therefore, unnecessary radio resource allocation and service option negotiation in the CDMA2000 system 12 can be prevented in advance.

On the other hand, when the determination result (S507), the CDMA2000 system 12 and the HAT 13 can support the data service before the handoff, the BS 14 sends a service supportable message to the corresponding HAT 13 (S511). Here, the service supportable message is a message indicating that data service before handoff can be supported.

Accordingly, the HAT 13 receives the service supportable message and requests the corresponding CDMA2000 system 12 to set up a call for resuming the data service that was in service before the handoff (S512).

Accordingly, the CDMA2000 system 12 receives the call setup request, performs radio resource allocation and service option negotiation, and performs data call setup (S513).

The BS 14 transmits a setup message to the PCF 16 (S514), receives a connection message from the PCF 16 (S515), and sets up a setup (S516).

Accordingly, the HAT 13 maintains a CDMA2000 active data session state in the CDMA2000 system 12 (S517).

Accordingly, the CDMA2000 system 12 provides the HAT 13 with a specific or fixed rate data service for the call using the second information transmission message (S518).

In addition, the embodiment according to the present invention is not limited to the above-mentioned, and can be implemented by various alternatives, modifications, and changes within the scope apparent to those skilled in the art.

As described above, according to the present invention, the HAT can guarantee the same packet data service before and after the handoff from the HRPD system having the difference in the data service rate that can be supported to the CDMA2000 system, and the CDMA2000 system negotiates unnecessary radio resource allocation and service options. You can reduce the system load by not doing this.

Claims (6)

In the case of handing off from the first mobile communication system to another kind of second mobile communication system, Monitoring an overhead channel of the second mobile communication system while collecting and managing service data information while maintaining an active data session state in the first mobile communication system; Determining whether the second mobile communication system and the terminal can support a data service before handoff based on the service data information; And providing a data service for the call by requesting a call setup and performing a handoff when the data service before the handoff can be supported. The method of claim 1, If the data service before the handoff cannot be supported, status information is displayed on the terminal without requiring call setup. The method of claim 1, The service data information, Handoff method between mobile communication systems characterized in that the collection is managed by the terminal. In the case of handing off from the first mobile communication system to another kind of second mobile communication system, Monitoring the system to collect and manage service data information while maintaining an active data session state in the first mobile communication system; Determining whether the second mobile communication system and the terminal can support a data service before handoff based on the service data information; And providing a data service for the call by requesting a call setup and performing a handoff when the data service before the handoff can be supported. The method of claim 4, wherein If the data service before the handoff cannot be supported, status information is displayed on the terminal without requiring call setup. The method of claim 4, wherein The service data information, Handoff method between mobile communication systems characterized in that the collection is managed by the PDSN.