WO2012033316A2

WO2012033316A2 - Network control single radio handover method and device between heterogeneous wireless networks

Info

Publication number: WO2012033316A2
Application number: PCT/KR2011/006547
Authority: WO
Inventors: 지정훈; 전홍석; 안윤영; 박창민
Original assignee: 한국전자통신연구원
Priority date: 2010-09-09
Filing date: 2011-09-05
Publication date: 2012-03-15
Also published as: WO2012033316A3

Abstract

Provided are a device and method for performing handover by detecting a state of another wireless network when only a wireless access interface for a current access network is activated in a mobile terminal. A handover controller performs communication between a mobile terminal performing a single radio handover and an information server managing access information for each wireless network. The handover controller obtains multi RAT access information used for accessing a network accessible at a current position of the mobile terminal. The handover controller obtains a network quality measurement result, which is measured using the multi RAT access information, from the mobile terminal, and determines a target network of the mobile terminal by using the network quality measurement result.

Description

Method and apparatus for network control single radio handover between heterogeneous wireless networks

The present invention relates to a method for a mobile terminal to reduce access delay and packet loss during handover between heterogeneous wireless networks.

Service providers that provide services such as Internet based multimedia subsystems (IMS) to mobile terminals are providing services through various heterogeneous access technologies and networks. In addition, mobile terminals are often configured to operate in a multi-mode such that multiple network accesses are possible. If the mobile terminal is configured to allow multiple network accesses, there is a need for a technique for receiving a seamless service while reducing the connection delay in the handover between heterogeneous networks. As such, a single radio handover has been proposed to reduce connection delay in handover between heterogeneous network accesses. Single radio handover means that only one access interface of the current access network remains available for transmission and reception during handover, while other access interfaces remain in a state where transmission is impossible, that is, only reception or no reception is possible. The method of performing handover.

Related prior art documents include Korean Publication No. 10-2005-23194 published on March 9, 2005, a handover method for preventing packet loss in a portable Internet network.

There is a need for an apparatus and method for performing a handover by measuring a state of another radio link with only an interface for accessing a network currently connected to a mobile terminal.

Provided are an apparatus and a method for performing a handover by measuring a state of another radio link while activating only an interface for accessing a network currently connected to a mobile terminal.

According to the present invention, it is possible to minimize the state in which the multiple radio access interfaces are simultaneously activated, thereby reducing the interference between the radio access interfaces and enabling the quality measurement of the multi radio link.

1 is a diagram illustrating a network in which a network controlled single radio handover is performed according to an embodiment of the present invention.

2 is a diagram illustrating an example of a wireless network distribution.

3 is a diagram illustrating a process of a network controlled single radio handover method according to an embodiment of the present invention.

4 is a block diagram illustrating a configuration of a mobile terminal for performing network controlled single radio handover according to an embodiment of the present invention.

5 is a block diagram illustrating a configuration of a handover controller for performing a network controlled single radio handover according to an embodiment of the present invention.

According to an aspect, a handover controller may include a communication unit configured to communicate with a mobile terminal performing a single radio handover and an information server managing connection information for each wireless network, and a network accessible through a communication unit at a current location of the mobile terminal. Acquiring multi-RAT access information used for access from an information server, obtaining network quality measurement results measured using the multi-RAT access information from the mobile terminal, and determining a target network of the mobile terminal using the network quality measurement results. It includes a handover decision unit.

According to another aspect of the present invention, a mobile terminal for performing a single radio handover, an information server for managing access information for each wireless network, and a method for operating a handover controller connected to the mobile terminal and the information server may include a current location of the mobile terminal. Acquiring, from the information server, multi-RAT access information including wireless network access information used to access a network accessible by the handover controller; the handover controller includes multi-RAT access information and uses network quality by using the multi-RAT access information. Transmitting a network quality measurement message requesting measurement to a mobile terminal, receiving network quality measurement results measured using multi-RAT access information included in the network quality measurement message from the mobile terminal, and network quality measurement results Using the destination network And a determining step.

According to another aspect of the present invention, a mobile terminal includes: an interface unit including a plurality of wireless connection interfaces to connect to a plurality of heterogeneous wireless networks, and connected to the first network through a first interface which is one of the plurality of wireless connection interfaces; If a network quality measurement request including multi-RAT access information used to connect to a wireless network adjacent to the current location of the mobile terminal is received from the handover controller through the first interface, at least one network using the multi-RAT access information is received. A network quality measurement unit for measuring quality and transmitting at least one network quality measurement result to a handover controller through a first interface, and a message instructing to perform handover including destination network connection information from the handover controller is received. When ordered, To the desired network, comprising: a handover to perform the handover.

According to another aspect of the present invention, there is provided a method of operating a mobile terminal connected to a handover controller connected to an information server for managing access information for each wireless network, wherein the mobile terminal controls the handover through a first interface that is one of a plurality of wireless access interfaces. Receiving a network quality measurement request including multi-RAT access information used to access a wireless network adjacent to a mobile terminal's current location from the mobile station, and measuring at least one network quality using the multi-RAT access information; Transmitting the at least one network quality measurement result to the handover controller through the first interface, and receiving a message instructing to perform a handover including the target network connection information from the handover controller according to the command. For performing a handover to the network It is.

A system for performing a network controlled single radio handover including a mobile terminal performing a single radio handover according to another aspect, an information server managing access information for each wireless network, and a handover controller connected to the mobile terminal and the information server The method of operation may include multi-RAT access information including wireless network connection information used to connect to a network accessible at the current location of the mobile terminal as the information server receives a network connection information request message from the handover controller. Transmitting to the mobile terminal a network quality measurement request message for requesting network quality measurement using the multi-RAT access information, wherein the handover controller includes multi-RAT access information; Using multi-RAT access information Measuring one network quality, transmitting at least one network quality measurement result to the handover controller, determining, by the handover controller using the network quality measurement result, a destination network, and determining the handover controller And sending a message to the mobile terminal instructing handover to the destination network.

Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. It should be noted that the same elements among the drawings are denoted by the same reference numerals and symbols as much as possible even though they are shown in different drawings. In the following description of the present invention, if it is determined that a detailed description of a related known function or configuration may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted.

The system in which the network control single radio handover of FIG. 1 is performed includes a mobile terminal 110 (Multi-Mode MS), a handover controller 120 (HandOver Controller), an information server 130 and a plurality of PoAs ( 140, 150, 160; Point of Attachment). The handover controller 120 may be called a handover controller or a handover control device.

The mobile terminal 110 includes a multimode interface composed of a plurality of radio access interfaces for accessing a heterogeneous network. For example, the mobile terminal 110 may include various types of interfaces such as a worldwide interoperability for microwace access (WiMAX) network interface, a WiFi network interface, a 3rd generation partnership project (3GPP) network interface, and the like as a multimode interface. .

In a preferred embodiment of the present invention, the multimode interface may be defined as an integrated type of heterogeneous network interfaces or may include some or all of several network interface types separately attached to a terminal. In addition, it should be noted that the multimode interface may be substituted and changed in various implementation manners. The mobile terminal 110 may be various mobile devices such as a mobile phone, a smart phone, a personal digital assistant (PDA), a personal computer, a laptop, and the like.

The mobile terminal 110 performs handover according to a single radio handover scheme. Accordingly, the mobile terminal 110 maintains only a single access interface of the current access network in a state capable of transmitting and receiving, and operates the other access interface in a state in which transmission is impossible, that is, only reception or even no reception is possible.

The handover controller 120 is connected to the mobile terminal 110 and the information server 130. As illustrated in FIG. 1, the handover controller 120 may be connected to the mobile terminal 110 through a PoA 140 of a network in which the mobile terminal 110 is currently connected and in service to perform message transmission and reception. . Alternatively, the message exchange between the handover controller 120 and the mobile terminal 110 may be performed through a medium access control (MAC) protocol or an upper IP transmission protocol (eg, UDP).

The information server 130 stores access information for each wireless network for each heterogeneous network. The wireless network access information may be stored in association with current location information of the mobile terminal 110. Here, the location information may be of various forms that can specify the location of the mobile terminal 110, such as global positioning system (GPS) information, radio cell location information, and point of attachment (PoA) identification information of layer 2 (L2). Information may be used. The access information for each wireless network of the information server 130 may be configured as heterogeneous wireless network access information adjacent to one wireless network based on the access information of one wireless network.

The information server 130 may transmit wireless network access information for the heterogeneous network to the handover controller 120 at the request of the handover controller 120. In addition, when the information server 130 receives a network connection information request message including the location information of the mobile terminal 110 from the handover controller 120, the mobile terminal 110 is accessible or at the corresponding location. May be configured to retrieve all wireless network connection information adjacent to the.

The plurality of

PoAs

140, 150, and 160 are devices such as a WiFi access point (AP) or a cellular and a WiMAX base station (BS) that provide a wired or wireless link connection of the mobile terminal 110.

2 is a diagram illustrating an example of a wireless network distribution.

Table 1 below shows an example of connection information for each wireless network established in the information server 130 with reference to FIG. 2. The wireless network access information for the heterogeneous network of the information server 130 of Table 1 is composed of heterogeneous wireless network access information adjacent to the location indicated by the 3GPP radio cell information based on the 3GPP radio cell information.

Table 1

Broadband 3GPP Wireless Access Information	WiMAX Wireless Information	WiFi wireless connection information
Ca	Ma
Cb	Mb	Fa, Fb

Referring to FIG. 2 and Table 1, when the information server 130 receives a network access information request message in which the location information of the mobile terminal 110 is Ca, the wireless network accessible from the location is connected to the broadband 3GPP network and the WiMAX network. The wireless network access information corresponding to Ca and Ma is transferred to the handover controller 120. If the location information of the mobile terminal 110 receives a network access information request message of Cb, the wireless network accessible from the location is identified as a broadband 3GPP network, a WiMAX network, and a WiFi network, and is assigned to Cb, Mb, Fa, and Fb. The wireless network access information is transmitted to the handover controller 120.

Table 1 exemplifies a case where adjacent heterogeneous wireless network access information is constructed based on 3GPP radio cell information, but heterogeneous wireless network access information of the information server 130 may be constructed in various forms.

The handover controller 120 determines the current location of the mobile terminal 110 and requests the information server 130 for wireless network connection information used to access a network accessible from the current location of the mobile terminal 110 ( 310). The handover controller 120 may obtain location information of the mobile terminal 110 through various methods. For example, when the mobile terminal 110 moves from the currently connected PoA 140 to the candidate PoA 1 150, the mobile terminal 110 may be notified of the location change from the candidate PoA 1 150 or the mobile terminal 110. . In this case, as the location information of the mobile terminal 110, the location information of the cell (Cell) currently connected to the terminal 110, L2 PoA (Point of Attachment) identification information, GPS information, and the like may be used.

The information server 130 may respond to the query of the handover controller 120 with a network connection information response message in response to the network connection information request of the handover controller 120 (320). The network connection information response message transmitted by the information server 130 to the handover controller 120 to respond to the query is accessible from the current location of the mobile terminal 110 other than the network to which the mobile terminal 110 is currently connected. All wireless network connection information is included.

The access information for all wireless networks accessible from the current location of the mobile terminal 110 may be referred to as multi-radio access technology access information. The multi-RAT access information includes information for accessing each radio link. For example, the multi-RAT access information may include a RAT type, a carrier frequency, a Point of Attachment (PoA) identifier supporting a L2 connection, a preamble, a PHY profile ID, and the like.

Here, the RAT type indicates the type of wireless network (eg WiMax, WiFi, 3GPP). The carrier frequency represents frequency information used to connect to the wireless network. The PoA identifier supporting the L2 connection means an identifier of each PoA. The preamble means an information value for synchronizing with the PoA, and the PHY profile ID includes physical connection information. Such multi-RAT access information is exemplary, and detailed information constituting the multi-RAT access information may vary according to the type of the wireless network.

The handover controller 120 transmits a network quality measurement request message (Single Radio scan request) to the mobile terminal 110 to request link quality measurement of the multi-radio radio (330). The network quality measurement request message includes the multi-RAT access information received from the information server 130. The network quality measurement request message may be transmitted through a wireless access interface of a network to which the multimode mobile terminal 110 is currently connected. In addition, the network quality measurement request message may be transmitted through a protocol on IP or an L2 frame of a currently connected network.

The mobile terminal 110 measures the wireless network quality by using the multi-RAT access information received from the handover controller 120 (340). In this case, when there are a plurality of wireless networks to which the mobile terminal 110 can connect, the multi-radio radio link quality measurement may be performed. When the power of the wireless access interface used for accessing the network included in the multi-RAT access information is turned off (Power-Off), the mobile terminal 110 supplies power to the corresponding wireless access interface to switch to a state in which reception is possible. The network quality can be measured by analyzing the received signal.

The mobile terminal 110 transmits the network quality measurement result to the handover controller 120 through a single radio scan response message (350).

The handover controller 120 determines a target network to which the mobile terminal 110 should handover by using the network quality measurement result received from the mobile terminal 110 (360). When the network quality measurement results of the plurality of radio links are received from the mobile terminal 110, a plurality of network quality measurement results may be compared to determine a network showing the best quality as the destination network.

The handover controller 120 includes the determined destination network information to the mobile terminal 110 and transmits a message instructing to handover to the destination network (370).

The mobile terminal 110 performs the handover to the destination network determined by the handover controller 120. The mobile terminal 110 may activate a radio access interface for accessing the determined destination network and deactivate the radio access interface used to access the previous network. The procedure for performing handover may vary according to the type of wireless network.

As described above, in the network controlled single radio handover method, the wireless connection information based on the current location of the mobile terminal is secured in advance from the information server before the handover controller on the network receives a handover command to the mobile terminal. By additionally providing at the time of the scan request, the mobile terminal can easily perform quality measurement of the multi-radio link.

According to an embodiment of the present invention, it is possible to minimize the state in which the multiple radio access interfaces are simultaneously activated to reduce the interference between the radio access interfaces and to measure the quality of the multi radio link.

4 is a block diagram illustrating a configuration of a mobile terminal 110 for performing a network controlled single radio handover according to an embodiment of the present invention.

The mobile terminal 110 may include an interface unit 410, a network quality measuring unit 420, and a handover performing unit 430. The interface unit 410 includes a plurality of wireless connection interfaces 412, 414, 416. Multiple wireless access interfaces 412, 414, 416 may be heterogeneous interfaces used to connect to heterogeneous wireless networks. Although three interfaces are illustrated in FIG. 3, the type and number of wireless access interfaces included in the interface unit 410 are not limited.

The mobile terminal 110 may operate according to a single radio handover. In this case, only one wireless access interface is activated in the interface unit 410 to maintain the network connected to and transmitted through the corresponding interface. The other wireless access interface is in a state in which transmission is impossible, that is, only reception is possible. Operation remains impossible until reception. Here, for convenience of explanation, it is assumed that the first interface 412 is currently active, and the remaining

interfaces

414 and 416 are deactivated.

When the network quality measurement is received from the handover controller 120 via the first interface 412, a quality measurement request message including multi-RAT access information used to access an adjacent PoA at the current location of the mobile terminal 110 is received. The unit 420 performs network quality measurement that can be accessed using the multi-RAT access information. The network quality measurement unit 420 may check whether an interface for accessing the wireless network included in the multi-RAT access information is operating. For example, when the second interface 414 is used to access a wireless network included in the RAT access information, the network quality measuring unit 420 may turn off the second interface 414 if the second interface 414 is turned off. Powered to 414 may be controlled to operate.

The network quality measurer 420 may measure network quality by using a signal received by the second interface 414 through the corresponding wireless network by using the multi-RAT access information. The network quality measuring unit 420 may include the second interface 414 and the third interface when the interfaces for accessing the wireless network included in the multi-RAT access information are the second interface 414 and the third interface 416. Each signal received from 416 may be used to measure network quality. The network quality measurer 420 may measure network quality using various parameters such as signal strength, signal quality, and received power strength parameters of the received signal.

The network quality measurer 420 transmits a quality measurement result response message including the measured network quality information to the handover controller 120 through the first interface 412.

The handover command may be received from the handover controller 120 through the first interface 412 including destination network connection information for the destination network determined based on the information of the quality measurement result response message. Then, the handover performer 430 performs a handover according to the handover command. When the second interface 414 is used to connect to the destination network, the handover performer 430 activates the second interface 414 to transmit and receive a signal through the second interface 414, and the remaining interface ( 412 and 416 may control the interface unit 410 to be deactivated.

5 is a block diagram showing the configuration of a handover controller 120 for performing a network controlled single radio handover according to an embodiment of the present invention.

The handover controller 120 may include a communication unit 510 and a handover determination unit 520. The communication unit 510 includes a communication interface for communicating with the mobile terminal 110 and the information server 130 for managing the connection information for each wireless network.

The handover decision unit 520 determines the current location of the mobile terminal 110.

The handover decision unit 520 controls the communication unit 510 to be used to access the network including the current location of the mobile terminal 110 to the information server 130 and accessible from the current location of the mobile terminal 110. You can request network connection information. The handover decision unit 520 sends a network connection information response message including the multi-RAT access information used to access the network adjacent to the current location of the mobile terminal 110 from the information server 130 through the communication unit 510. Receive. The handover decision unit 520 includes the received multi-RAT access information and transmits a quality measurement request message for requesting quality measurement of a network accessible by using the multi-RAT access information through the communication unit 510 to the mobile terminal 110. To transmit.

When the handover decision unit 520 receives the quality measurement result response message including the quality measurement result from the mobile terminal 110, the handover determination unit 520 determines the destination network to which the mobile terminal 110 performs handover by using the received quality measurement result. do. Then, the handover decision unit 520 transmits a message to the mobile terminal 110 instructing the handover to the destination network determined through the communication unit 510.

The invention can also be embodied as computer readable code on a computer readable recording medium. Computer-readable recording media include all kinds of recording devices that store data that can be read by a computer system. Examples of computer-readable recording media include ROM, RAM, CD-ROM, magnetic tape, floppy disk, optical data storage, and the like, which are also implemented in the form of carrier waves (for example, transmission over the Internet). It also includes. The computer readable recording medium can also be distributed over network coupled computer systems so that the computer readable code is stored and executed in a distributed fashion.

The best embodiments have been disclosed in the drawings and specification above. Although specific terms have been used herein, they are used only for the purpose of describing the present invention and are not used to limit the scope of the present invention as defined in the meaning or claims. Therefore, those skilled in the art will understand that various modifications and equivalent other embodiments are possible from this. Therefore, the true technical protection scope of the present invention should be construed to include various embodiments which are not limited to the above-described embodiments but within the scope equivalent to those described in the claims.

Claims

A communication unit configured to communicate with a mobile terminal performing a single radio handover and an information server managing access information for each wireless network; And

The multi-RAT access information used to access the network accessible from the current location of the mobile terminal through the communication unit is obtained from the information server, and the network quality measurement result measured using the multi-RAT access information from the mobile terminal. A handover determination unit configured to acquire and determine a target network of the mobile terminal using the network quality measurement result; Handover controller comprising a.
The method of claim 1,

The handover determiner obtains current location information of the mobile terminal, and the location information includes at least one of GPS information, radio cell location information, and layer of point of attachment (PoA) identification information.
The method of claim 1,

And the handover determiner transmits a network access information request message for requesting multi-RAT access information used to access a network accessible from a current location of the mobile terminal to the information server through the communication unit.
The method of claim 1,

When the handover decision unit receives the multi-RAT access information from the information server, the handover determination unit includes the multi-RAT access information and sends a network quality measurement request message for requesting network quality measurement using the multi-RAT access information through the communication unit. Handover controller for transmitting to the mobile terminal.
A method of operation of a handover controller connected to an mobile terminal for performing a single radio handover and an information server for managing access information for each wireless network, the method comprising:

The handover controller obtaining multi-RAT access information from the information server, the multi-RAT access information including wireless network access information used to access a network accessible at a current location of a mobile terminal;

The handover controller including the multi-RAT access information and transmitting a network quality measurement request message to the mobile terminal to request network quality measurement using the multi-RAT access information;

Receiving a network quality measurement result measured using the multi-RAT access information included in the network quality measurement request message from the mobile terminal; And

And determining a destination network using the result of the network quality measurement.
The method of claim 5,

Before obtaining the multi-RAT access information from the information server,

The handover controller acquiring current location information of the mobile terminal; And

Sending a network access information request message to the information server requesting multi-RAT access information used to access a network accessible at a current location of the mobile terminal.
The method of claim 5,

And sending a message to the mobile terminal instructing to handover to the determined destination network.
An interface unit including a plurality of wireless access interfaces to access a plurality of heterogeneous wireless networks, and connecting to the first network through a first interface which is one of the plurality of wireless access interfaces;

When a network quality measurement request including multi-RAT access information used to access a wireless network adjacent to a current location of a mobile terminal is received from the handover controller through the first interface, at least one of the multi-RAT access information is used. A network quality measuring unit for measuring a network quality of the network and transmitting the at least one network quality measurement result to the handover controller through the first interface; And

A handover performer configured to perform a handover to the destination network according to the command if a message for commanding the handover including destination network access information is received from the handover controller; A mobile terminal comprising a.
The method of claim 8,

The network quality measuring unit, when the power of the second interface for performing network access included in the multi-RAT access information of the plurality of interfaces is turned off, supplies power to the second interface, and through the second interface A mobile terminal which controls to receive a signal from a network to which it is connected.
The method of claim 8,

And when the second interface of the plurality of interfaces is used to access the destination network, the handover performer activates the second interface to transmit and receive a signal through the second interface, and deactivates the other interface.
A method of operating a mobile terminal connected to a handover controller connected to an information server for managing access information for each wireless network, the method comprising:

The mobile terminal requests a network quality measurement request including multi-RAT access information used to access a wireless network adjacent to a current location of the mobile terminal from the handover controller through a first interface, which is one of the plurality of wireless access interfaces. Receiving;

Measuring at least one network quality using the multi-RAT access information;

Transmitting the at least one network quality measurement result to the handover controller via the first interface; And

Performing a handover to the destination network according to the command if a message is received from the handover controller instructing to perform handover including destination network access information; How to include.
The method of claim 11,

Measuring at least one network quality using the multi-RAT access information,

When the power of the second interface that performs network access included in the multi-RAT access information of the plurality of interfaces is turned off, power is supplied to the second interface to receive a signal from a network connected through the second interface. Controlling to receive.
A mobile terminal performing a single radio handover, an information server for managing access information for each wireless network, and a method of operating a system for performing a network controlled single radio handover including a handover controller connected to the mobile terminal and the information server. As

The information server, upon receiving a network access information request message from the handover controller, handovers the multi-RAT access information including wireless network access information used to access a network accessible from the current location of the mobile terminal. Transmitting to a controller;

The handover controller including the multi-RAT access information and transmitting a network quality measurement request message to the mobile terminal to request network quality measurement using the multi-RAT access information;

Measuring, by the mobile terminal, at least one network quality using the multi-RAT access information, and transmitting the at least one network quality measurement result to the handover controller;

Determining, by the handover controller, a destination network using the network quality measurement result; And

And the handover controller sending a message to the mobile terminal instructing to handover to the determined destination network.
The method of claim 13,

The access information for each wireless network of the information server is composed of heterogeneous wireless network access information adjacent to the one wireless network based on the access information of one wireless network.
The method of claim 13,

The multi-RAT access information includes at least one of a RAT type, a carrier frequency, a Point of Attachment (PoA) identifier supporting a L2 connection, a preamble, and a PHY profile ID.
The method of claim 13,

The mobile terminal performing a single radio handover to the destination network according to the command if a message is received from the handover controller to command handover including the destination network access information; .
The method of claim 13,

Measuring, by the mobile terminal, at least one network quality using the multi-RAT access information,

When the power of the network accessing interface included in the multi-RAT access information of the plurality of interfaces included in the mobile terminal is turned off, the power is supplied to the interface to receive a signal from a network connected through the interface. Controlling to; How to include more.