KR20080075464A - Method and apparatus for performing handover - Google Patents

Abstract

A method and an apparatus for executing handover are provided to enable a mobile node to prepare for handover previously so as to speedily execute handover by enabling the mobile node to predict that the mobile node will move to a new network. A mobile node(1), which moves between heterogeneous networks, comprises a network information confirmation part(15), an interface enable part(16), and a handover execution part(19). The network information confirmation part confirms whether a signal received from a node which connects the mobile node to the first network includes network information which indicates that the mobile node is moving from the first network to the second network. If it is confirmed that the received signal includes such network information, the interface enable part enables an interface which supports the second network. Using the enabled interface, the handover execution part selectively executes handover according to a change of networks.

Description

Method and apparatus for performing handover {Method and apparatus for performing handover}

The present invention relates to a method and apparatus for performing handover in a wireless communication environment, and more particularly, to an apparatus and method for performing handover at high speed in an environment in which various communication networks complying with different communication standards are mixed.

3GPP (3 Generation Partnership Project), Institute of Electrical and Electronics Engineers (IEEE) 802.16, IEEE 802.11, and Bluetooth are several specifications for wireless communications. Mobile nodes (MNs), which can use various communication networks in a mixed environment of various communication networks conforming to different communication standards, have been released. Such a mobile node has a plurality of interfaces supporting various communication networks. When the type of communication network in which the mobile node is located changes as the mobile node moves, the mobile node selects and uses an interface supporting the current communication network.

If a mobile node uses one interface but uses another interface, handover should be performed according to the interface change. However, as the number of users using the mobile communication service is rapidly increased and the mobile communication service supporting the multimedia communication is activated, it is required to provide seamless communication to the mobile user. Accordingly, the importance of high speed handover has been highlighted. In addition, conventionally, since the mobile node performs a handover in a state in which all of the interfaces are enabled, there is a problem in that all interfaces are always in the enabled state in preparation for handover.

An object of the present invention is to provide a method and apparatus for preparing a handover in advance to perform a faster handover by enabling the mobile node to predict that the mobile node is moving to a new network. The present invention provides a computer-readable recording medium having recorded thereon a program for executing the method on a computer.

According to the present invention for solving the above technical problem, the first handover method in a mobile node moving between heterogeneous networks is a signal received from the node connecting the mobile node to the first type network; Checking network information indicating that the network is moving from the first type network to the second type network; And selectively performing a handover according to the change of the type of the network in which the mobile node is located, based on the confirmation.

In a first handover apparatus in a mobile node moving between heterogeneous networks according to the present invention for solving the other technical problem, a signal received from a node connecting the mobile node to the first type network is A network information checking unit for confirming whether the mobile node includes network information indicating that the mobile node is moving from the first type network to the second type network; And a handover performer configured to selectively perform a handover according to a change in the type of a network in which the mobile node is located, based on the confirmation in the network information checker.

According to another aspect of the present invention, there is provided a method of performing a second handover in a mobile node moving between heterogeneous networks, wherein a signal received from a node connecting the mobile node to a first slave network is received by the mobile node. Determining whether is a network signal indicating that the network is moving from the first type network to the second type network; And selectively performing a handover according to the change of the type of the network in which the mobile node is located based on the determination in the step.

According to another aspect of the present invention, there is provided a device for performing a second handover in a mobile node moving between heterogeneous networks, wherein a signal received from a node connecting the mobile node to a first slave network is received by the mobile node. A network signal discrimination unit for determining whether the network signal indicates that the network signal is moving from the first type network to the second type network; And a handover performer for selectively performing a handover according to a change in the type of a network in which the mobile node is located, based on the determination by the network signal discriminator.

In order to solve the above further technical problem, the present invention provides a computer-readable recording medium having recorded thereon a program for executing the above-described first handover method on a computer.

In order to solve the above another technical problem, the present invention provides a computer-readable recording medium having recorded thereon a program for executing the above-described second handover method on a computer.

According to the present invention, by enabling the mobile node to predict that the mobile node is moving to a new network, it is possible to prepare a handover in advance and perform a faster handover. In addition, according to the present invention, it is possible to perform a handover in a state in which the mobile node enables only the interface currently being used, thereby reducing the power consumption of the mobile node. In particular, since the mobile node uses a portable battery, the utility of reducing power consumption is very large.

Hereinafter, with reference to the drawings will be described embodiments of the present invention;

1 is a diagram illustrating a first communication environment to which preferred embodiments of the present invention are applied.

Referring to FIG. 1, the first communication environment to which the present embodiments are applied is an environment in which various communication networks complying with different communication standards are mixed, and a wireless LAN based on an IEEE 802.11 standard is located inside a 3GPP standard based cellular network. The communication environment is shown very briefly for the sake of clarity, and the communication environment to be actually implemented may include many other nodes in addition to the illustrated nodes.

A wireless LAN based on the IEEE 802.11 standard consists of a mobile node 1, a first access point (AP) 21, a second access point 22, and an access router (AR) 3 do.

The mobile node 1 is a communication terminal carried by a user. In this embodiment, the moving node 1 moves as shown in FIG. 1 in accordance with the movement of the user.

The first access point 21 and the second access point 22 are nodes that communicate wirelessly with the mobile node 1. According to IEEE 802.11, an effective distance of radio waves transmitted from an access point, that is, an area managed by the access point is called a basic service set (BSS). In FIG. 1, an area managed by the first access point 21 is designated as a first BSS and an area managed by the second access point 22 as a second BSS.

The access router 3 transmits a signal received from the mobile node 1 via the first access point 21 or the second access point 22 to a subnet where the access router 3 is located. to be.

The 3GPP standard based cellular network is composed of a mobile node 1, a Radio Base Station (RBS) 4, and a Serving General Packet Radio Service (GPRS) Support Node (5).

The RBS (Radio Base Station) 4 is a node that communicates wirelessly with the mobile node 1. In Fig. 1, the effective distance of radio waves transmitted from the RBS 4, that is, the area managed by the RBS 4 is indicated by the 3GPP domain.

SGSN 5 is a node connecting RBS 2 and GGSN 4 via a 3GPP backbone (not shown) at an intermediate point between RBS 4 and a Gateway GPRS Support Node (GGSN) (not shown).

In the first communication environment illustrated in FIG. 1, the mobile node 1 has a plurality of interfaces supporting a wireless LAN based on the IEEE 802.11 standard and a cellular network based on the 3GPP standard, and passes through 3GPP through BBS 1 and BBS 2. You are moving to the domain.

2 is a diagram illustrating a second communication environment to which preferred embodiments of the present invention are applied.

Referring to FIG. 2, the second communication environment to which the present embodiments are applied is an environment in which various communication networks complying with different communication standards are mixed, and is inside a wireless metropolitan area network (MAN) based on the IEEE 802.16 standard. IEEE 802.11 standard based wireless LAN is located. The communication environment is shown very briefly for the sake of clarity, and the communication environment to be actually implemented may include many other nodes in addition to the illustrated nodes.

The WLAN based on the IEEE 802.11 standard is the same as described above, and will be omitted.

An IEEE 802.16 based wireless metropolitan area network consists of a mobile node 1, a base station (BS) 6, and an access router 7.

BS 6 is a node that communicates wirelessly with mobile node 1. In FIG. 2, the effective distance of the radio wave transmitted from the BS 6, that is, the area managed by the BS 6 is indicated by the IEEE 802.16 domain.

The access router 7 is a router that transmits a signal received from the mobile node 1 to the wide area network in which the access router 3 is located.

In the second communication environment illustrated in FIG. 2, the mobile node 1 includes a plurality of interfaces supporting an IEEE 802.11 standard-based wireless LAN and an IEEE 802.16-based wireless metropolitan area network, and passes through BBS 1 and BBS 2. You are moving to the IEEE 802.16 domain.

3 is a block diagram of an apparatus for performing first handover according to an embodiment of the present invention.

Referring to FIG. 3, the apparatus for performing the first handover at the second AP 22 includes a scan signal generator 221, a network information inserter 222, and a signal transmitter 223. The apparatus for performing the first handover at the second AP 22 inserts network information indicating that the mobile node is moving from the first type network to the second type network in the scan signal so that the mobile node 1 moves to the new network. You can predict that you are moving.

The scan signal generator 221 generates a signal necessary for the mobile node 1 to scan the second AP 22, that is, a scan signal indicating a cell managed by the second AP 22. According to the IEEE 802.11 standard, such a scan signal includes a beacon frame and a probe response frame. The beacon frame is a signal periodically transmitted by the second AP 22, the probe response frame is a response signal to the probe request frame received from the mobile node (1). The former is called passive scanning and the latter is called active scanning.

The network information inserting unit 222 inserts network information indicating that the mobile node is moving from the first type network to the second type network in the scan signal generated by the scan signal generation unit 221. In the first communication environment illustrated in FIG. 1, a first type network becomes a wireless LAN based on the IEEE 802.11 standard, and a second type network becomes a cellular network based on the 3GPP standard. On the other hand, in the second communication environment illustrated in FIG. 2, the first type network becomes a wireless LAN based on the IEEE 802.11 standard, and the second type network becomes a wireless metropolitan communication network based on the IEEE 802.16 standard.

4 is a diagram illustrating a format of a beacon frame and a probe response frame according to an embodiment of the present invention.

Referring to FIG. 4, a management frame according to the IEEE 802.11 standard includes a frame control field 401, a duration field 402, and a destination address field 403. Source address field 404, BSS ID field 405, sequence control field 406, frame body field 407. , And frame check sequence field 408.

Here, the frame control field 401 may include a protocol version field 4011, a type field 4012, a subtype field 4013, and the like. It consists of fields.

According to the IEEE 802.11 standard, the value of the type field of a management frame is zero. Therefore, the value of the type field of the beacon frame and the probe response frame belonging to the management frame is also zero. However, the value of the subtype field of the beacon frame is 1000 and the value of the subtype field of the probe response frame is 0101.

The frame body field 407 of the beacon frame includes a time stamp field 4041, a beacon interval field 4042, a capability information field 4073, and a TIM field. Indication Map) 4404, and other fields. Similarly, the frame body field 407 of the probe response frame consists of a time stamp field 4075, a beacon interval field 4076, a performance information field 4077, a TIM field 4078, and other fields.

Herein, the performance information fields 4073 and 4077 include an extended service set field (40731), an independent BSS field (40732), a content free pollable field (40733), and a CF poll. A request field (Contention Free poll request) 40734, a privacy field 40735, and a DID field (Domain Identifier field) 40407.

As shown in FIG. 4, a reserved field of the performance information fields 4073 and 4077 of the frame body field 407 of the beacon frame or the probe response frame for inserting network information into the beacon frame or the probe response frame. A part of is available. In FIG. 4, this portion is indicated as a domain identifier (DID). For example, 00 indicating IEEE 802.11, 01 indicating 3GPP, 10 indicating IEEE 802.16, etc. may be recorded in the DID field.

 Referring back to FIG. 3, the signal transmitter 223 transmits a scan signal in which network information is inserted by the network information inserter 222 to the mobile node 1. That is, the signal transmitter 223 periodically transmits a beacon frame in which network information is inserted, or transmits a probe response frame in which network information is inserted as a response to the probe request frame.

The first handover apparatus in the mobile node 1 includes a signal receiver 11, a signal discriminator 12, a cell information confirmer 13, a cell change determiner 14, and a network information confirmer 15. , The interface enable unit 16, the network change determiner 17, the interface disable unit 18, and the handover performer 19. Here, the handover performer 19 includes an intercell handover performer 191 and a manganese handover performer 192.

The signal receiver 11 receives a signal from the second AP 22 connecting the mobile node 1 to the first type network. However, the mobile node 1 should be located in a cell managed by the second AP 22.

The scan signal determiner 12 determines whether the signal received by the signal receiver 11 is a scan signal indicating a cell managed by the second AP 22. That is, the scan signal determiner 12 determines whether the signal received from the second AP 22 is a beacon frame or probe response frame indicating the second BSS. When the value of the type field of the signal received by the signal receiver 11 is 0 and the value of the subtype field is 1000, the signal received by the signal receiver 11 is a beacon frame, the value of the type field is 0, and the sub If the value of the type field is 0101, the signal received by the signal receiver 11 is a probe response frame.

 When the cell information confirming unit 13 determines that the scan signal is determined to be a scan signal, the cell information confirming unit 13 checks the cell information included in the signal. As described above, the beacon frame and the probe response frame, which are a type of management frame, include a BSS ID field 405. In this BSS ID field 405, the ID of the BSS managed by the access point is recorded. The cell information checking unit 13 may check cell information by referring to the BSS ID field 405 of the beacon frame or the probe response frame.

The cell change determination unit 14 determines whether or not to change the cell in which the mobile node 1 is located based on the confirmation in the cell information confirmation unit 13. The cell change determiner 14 determines that the cell where the mobile node 1 is located is changed if the ID of the BSS confirmed by the cell information confirmer 13 is not the same as the ID of the previously confirmed BSS.

The intercell handover performer 191 selectively performs a handover according to the change of the cell where the mobile node 1 is located, based on the discrimination by the scan signal determiner 12. That is, if it is determined that the cell where the mobile node 1 is located is changed by the cell change determiner 14, the intercell handover performer 191 performs handover according to the change of the cell. In this case, if the cell change corresponds to a simple BSS change, only handover is performed at the link layer. If the cell change corresponds to a change of the subnet, the handover is performed at the link layer and the Internet Protocol (IP) layer. do.

The network information checking unit 15 checks whether the signal received by the signal receiving unit 11 includes network information indicating that the mobile node 1 is moving from the first type network to the second type network. That is, the network information checking unit 15 checks with reference to the DID field 40736 among the pending fields of the performance information fields 4073 and 4077 of the frame body field 407 of the beacon frame or the probe response frame shown in FIG. 4. do. This is because, as described above, the network information is recorded in the DID field 40736 among the reserved fields of the performance information fields 4073 and 4077 of the frame body field 407 of the beacon frame or the probe response frame.

 The interface enable unit 16 enables the interface supporting the second type network when the network information confirming unit 15 determines that the network information is included. That is, if the network enabler 16 determines that the network information checking unit 15 includes the 3GPP standard-based cellular network DID, the interface enabler 16 enables the interface supporting the 3GPP standard-based cellular network and checks network information. If it is determined in section 15 that the wireless metropolitan area network DID based on the IEEE 802.16 standard is included, the interface supporting the wireless metropolitan area network based on the IEEE 802.16 standard is enabled.

The network change determiner 17 determines whether to change the type of the network in which the mobile node 1 is located. That is, the network change determiner 17 determines the use of the enabled interface by the interface enabler 16 by referring to the use environment of the interface supporting the first type network. In more detail, the network change determining unit 17 cannot continuously use the interface supporting the first type network when the received signal strength is weak using the interface supporting the first type network. Then decide to use an interface that supports the second type of network.

The interface disable unit 18 disables the interface supporting the first type network when the network change determination unit 17 determines to use an interface supporting the second type network. Therefore, according to the present embodiment, the mobile node 1 can perform the handover while enabling only the interface currently being used, so that the conventional problem that all interfaces must be left enabled can be solved. It became. As a result, the power consumption of the mobile node can be significantly reduced. In particular, since the mobile node uses a portable battery, the utility of reducing power consumption is very large.

The network handover execution unit 192 selectively performs a handover according to the change of the type of the network in which the mobile node 1 is located, based on the confirmation in the network information confirmation unit 15. That is, when the network changeover determiner 192 determines to use an interface supporting the second type network by the network change determiner 17, the interface disabling unit 18 stops using the disabled interface. Then, the interface enable unit 16 starts using the enabled interface. In this case, when the network changeover determiner 192 determines that the network change determiner 17 uses an interface supporting the 3GPP standard-based cellular network, the network handover execution unit 192 moves from the IEEE 802.11-based WLAN to the 3GPP standard-based cellular network. When performing a handover to change and the network change determination unit 17 determines to use an interface supporting the IEEE 802.16 standard based wireless metropolitan area network, the IEEE 802.16 standard based wireless metropolitan area network from the IEEE 802.11 based WLAN. Perform handover to change to.

5 is a flowchart of a method for performing first handover at an access point according to an exemplary embodiment of the present invention.

Referring to FIG. 5, the method of performing the first handover in the second AP 22 according to the present embodiment includes the following steps. The method of performing the first handover in the second AP 22 includes steps that are processed in time series in the apparatus for performing the first handover in the second AP 22 described above. Therefore, even if omitted below, the description of the apparatus for performing the first handover in the second AP 22 is also applied to the method of performing the first handover in the second AP 22.

In step 51, the second AP 22 generates a scan signal indicating a cell managed by the second AP 22.

In step 52, the second AP 22 inserts network information indicating that the mobile node is moving from the first type network to the second type network in the scan signal generated in step 51.

In step 53, the second AP 22 transmits the scan signal into which the network information is inserted in step 52 to the mobile node 1.

6 is a flowchart of a first handover method performed in a mobile node according to an embodiment of the present invention.

Referring to FIG. 6, the method for performing first handover in the mobile node 1 according to the present embodiment includes the following steps. The method of performing a first handover in the present mobile node 1 consists of the steps processed in time series in the apparatus for performing the first handover in the above-described mobile node 1. Therefore, even if omitted below, the description of the apparatus for performing the first handover in the mobile node 1 also applies to the method of performing the first handover in the mobile node 1.

In step 61, the mobile node 1 receives a signal from the second AP 22 connecting the mobile node 1 to the first type network.

In step 62, the mobile node 1 determines whether the signal received in step 61 is a scan signal indicating a cell managed by the second AP 22. That is, in step 62, the mobile node 1 determines whether the signal received from the second AP 22 is a beacon frame or probe response frame indicating the second BSS.

If it is determined in step 62 that the mobile node 1 is a scan signal, the mobile node 1 checks the cell information included in the signal.

In step 64, the mobile node 1 determines whether to change the cell in which the mobile node 1 is located based on the confirmation in step 63.

In step 65, the mobile node 1 selectively performs a handover according to the change of the cell where the mobile node 1 is located, based on the determination in step 64. That is, if it is determined in step 65 that the cell where the mobile node 1 is located is changed in step 64, the mobile node 1 performs handover according to the change of the cell.

In step 66, the mobile node 1 checks whether the signal received in step 61 includes network information indicating that the mobile node 1 is moving from the first type network to the second type network. That is, in step 66, the mobile node 1 refers to the DID field 40736 among the pending fields of the performance information fields 4073 and 4077 of the frame body field 407 of the beacon frame or the probe response frame shown in FIG. 4. Check it. This is because, as described above, the network information is recorded in the DID field 40736 among the reserved fields of the performance information fields 4073 and 4077 of the frame body field 407 of the beacon frame or the probe response frame.

 If it is determined in step 67 that the mobile node 1 includes network information in step 66, the mobile node 1 enables an interface supporting the second type network. That is, in step 67, when the mobile node 1 is determined to include 3GPP standard-based cellular network information in step 66, the mobile node 1 enables an interface supporting the 3GPP standard-based cellular network, and in step 66, the IEEE 802.16 standard is based. If it is confirmed that the wireless metropolitan area information of the wireless metropolitan area network based on the IEEE 802.16 standard, enabling the interface.

In step 68, the mobile node 1 determines whether to change the type of the network in which the mobile node 1 is located. That is, in step 68, the mobile node 1 determines the use of the enabled interface by the interface enable unit 16 by referring to the use environment of the interface supporting the first type network. In more detail, in step 68, the mobile node 1 may continue to use the interface supporting the first type network when the received signal strength is weak using the interface supporting the first type network. It decides that it is impossible and decides to use an interface supporting the second type network.

If it is determined in step 69 that the mobile node 1 uses an interface supporting the second type network in step 68, the mobile node 1 disables the interface supporting the first type network.

In step 610, the mobile node 1 selectively performs a handover according to the change of the type of the network in which the mobile node 1 is located, based on the confirmation in step 66. That is, in step 610, if the mobile node 1 determines to use an interface supporting the second type network in step 68, the mobile node 1 stops using the disabled interface in step 69, and the mobile node 1 stops using the enabled interface in step 67. Start using In this case, if it is determined in step 610 that the mobile node 1 uses an interface supporting the 3GPP standard cellular network in step 68, the mobile node 1 changes the handover from the IEEE 802.11 based WLAN to the 3GPP standard cellular network. If it is determined in step 68 to use an interface supporting an IEEE 802.16 standard based wireless metropolitan area network, a handover is performed to change from an IEEE 802.11 based wireless LAN to an IEEE 802.16 standard based wireless metro area network.

7 is a block diagram of an apparatus for performing a second handover according to an embodiment of the present invention.

Referring to FIG. 7, the apparatus for performing second handover at the second AP 22 includes a scan signal generator 224, a network signal generator 225, and a signal transmitter 226. The apparatus for performing a second handover at the second AP 22 transmits a new signal indicating that the access point is moving from the first type network to the second type network, that is, the network signal so that the mobile node 1 makes a new network. To predict that you are moving to.

The scan signal generator 224 generates a signal necessary for the mobile node 1 to scan the second AP 22, that is, a scan signal indicating a cell managed by the second AP 22. According to the IEEE 802.11 standard, these scan signals include beacon frames and probe response frames.

The network signal generator 225 generates a network signal indicating that the mobile node 1 is moving from the first type network to the second type network. In the first communication environment illustrated in FIG. 1, a first type network becomes a wireless LAN based on the IEEE 802.11 standard, and a second type network becomes a cellular network based on the 3GPP standard. On the other hand, in the second communication environment illustrated in FIG. 2, the first type network becomes a wireless LAN based on the IEEE 802.11 standard, and the second type network becomes a wireless metropolitan communication network based on the IEEE 802.16 standard.

8 is a diagram illustrating a format of a domain identifier (DID) frame according to an embodiment of the present invention.

Referring to FIG. 8, a management frame according to the IEEE 802.11 standard includes a frame control field 801, a period field 802, a destination address field 803, a source address field 804, and a BSS ID field 805. , Order control field 806, frame body field 807, and frame check order field 808.

Here, the frame control field 801 is composed of a protocol version field 8011, a type field 8012, a subtype field 8013, and other fields.

As illustrated in FIG. 8, the subtype field of the frame control field of the management frame may be used to define a new signal indicating that the access point is located at the boundary of the subnet, that is, the new frame. That is, the value of the subtype field may be set to any one of 0110-0111 to indicate that it is a network signal. These values are not specified in the IEEE 802.11 standard. A value of 0 in the type field indicates a management frame. In this embodiment, to indicate that it is a network signal, a management frame in which the value of the subtype field is set to one of 0110-0111 will be referred to as a DID frame.

 Referring back to FIG. 7, the signal transmitter 226 transmits the scan signal generated by the scan signal generator 224 or the network signal generated by the network signal generator 225 to the mobile node 1. That is, the signal transmitter 226 transmits a scan signal to inform the mobile terminal that it is located in the cell it manages, and transmits a network signal to inform that the mobile node is moving to a new network.

The apparatus for performing second handover in the mobile node 1 includes a signal receiver 71, a signal discriminator 72, a cell information confirmer 73, a cell change determiner 74, and a network signal discriminator 75. , The interface enable unit 76, the network change determiner 77, the interface disable unit 78, and the handover performer 79. Here, the handover performer 79 is composed of an inter-cell handover performer 791 and a manganese handover performer 792.

The signal receiver 71 receives a signal from the second AP 22 connecting the mobile node 1 to the first type network. However, the mobile node 1 should be located in a cell managed by the second AP 22.

The scan signal determining unit 72 determines whether the signal received by the signal receiving unit 71 is a scan signal indicating a cell managed by the second AP 22. That is, the scan signal determination unit 72 determines whether the signal received from the second AP 22 is a beacon frame or probe response frame indicating the second BSS. If the value of the type field of the signal received by the signal receiver 71 is 0 and the value of the subtype field is 1000, the signal received by the signal receiver 71 is a beacon frame, the value of the type field is 0, and the sub If the value of the type field is 0101, the signal received by the signal receiver 71 is a probe response frame.

The cell information confirming unit 73 checks the cell information included in the signal when the scan signal determining unit 72 determines that the scan signal is the scan signal. As described above, the beacon frame and the probe response frame, which are a type of management frame, include a BSS ID field 405. In this BSS ID field 405, the ID of the BSS managed by the access point is recorded. The cell information checking unit 73 may check the cell information by referring to the BSS ID field 405 of the beacon frame or the probe response frame.

The cell change determiner 74 determines whether to change the cell in which the mobile node 1 is located based on the confirmation by the cell information confirmer 73. The cell change determiner 74 determines that the cell where the mobile node 1 is located is changed if the ID of the BSS confirmed by the cell information checker 73 is not the same as the ID of the BSS previously confirmed.

The intercell handover performer 791 selectively performs a handover according to the change of the cell where the mobile node 1 is located, based on the discrimination by the scan signal determiner 72. That is, if it is determined that the cell where the mobile node 1 is located is changed by the cell change determiner 74, the intercell handover performer 791 performs handover according to the change of the cell. In this case, if the cell change corresponds to a simple BSS change, only handover is performed at the link layer. If the cell change corresponds to a change of the subnet, the handover is performed at the link layer and the Internet Protocol (IP) layer. do.

The network signal discriminating unit 75 determines whether the signal received by the signal receiving unit 71 is a network signal indicating that the mobile node 1 is moving from the first type network to the second type network. That is, the network signal discrimination unit 75 determines by referring to the values recorded in the type field 8012 and the subtype field 8013 of the frame control field 801 of the management frame.

If the interface enable unit 76 determines that the network signal determination unit 75 is a network signal, the interface enable unit 76 enables an interface supporting the second type network. That is, if the interface enabler 76 determines that the network signal determination unit 75 is a DID frame indicating a 3GPP standard based cellular network, the interface enable unit 76 enables an interface supporting the 3GPP standard based cellular network, and the network signal. If it is determined by the determination unit 75 that the DID frame indicating a wireless metropolitan area network based on the IEEE 802.16 standard, enable the interface supporting the wireless metropolitan area network based on the IEEE 802.16 standard.

The network change determiner 77 determines whether the type of the network in which the mobile node 1 is located is changed. That is, the network change determiner 77 determines the use of the interface enabled by the interface enable unit 76 with reference to the use environment of the interface supporting the first type network. In more detail, the network change determiner 77 cannot continuously use the interface supporting the first type network when the received signal strength is weak using the interface supporting the first type network. Then decide to use an interface that supports the second type of network.

The interface disable unit 78 disables the interface supporting the first type network when the network change determining unit 77 determines to use an interface supporting the second type network. Therefore, according to the present embodiment, the mobile node 1 can perform the handover while enabling only the interface currently being used, so that the conventional problem that all interfaces must be left enabled can be solved. It became. As a result, the power consumption of the mobile node can be significantly reduced. In particular, since the mobile node uses a portable battery, the utility of reducing power consumption is very large.

The network handover execution unit 792 selectively performs a handover according to the change of the type of the network in which the mobile node 1 is located, based on the confirmation in the network signal determination unit 75. That is, when the network changeover determiner 792 determines to use an interface supporting the second type network by the network change determiner 77, the interface disable unit 78 stops using the disabled interface. Then, the interface enable unit 76 starts using the enabled interface. In this case, when the network changeover determiner 792 determines that the network change determiner 77 uses an interface supporting the 3GPP standard-based cellular network, the network changeover unit 792 moves from the IEEE 802.11-based WLAN to the 3GPP standard-based cellular network. If the network change decision unit 77 decides to use an interface supporting the IEEE 802.16 standard based wireless metropolitan area network, the wireless change network based on the IEEE 802.16 standard is used. Perform handover to change to.

9 is a flowchart of a method for performing a second handover in an access point according to an embodiment of the present invention.

Referring to FIG. 9, the method of performing the second handover in the second AP 22 according to the present embodiment includes the following steps. The method of performing the second handover in the second AP 22 includes steps that are processed in time series in the apparatus for performing the second handover in the second AP 22 described above. Therefore, even if omitted below, the description of the apparatus for performing the second handover in the second AP 22 is also applied to the method of performing the second handover in the second AP 22.

In operation 91, the second AP 22 generates a scan signal indicating a cell managed by the second AP 22.

In step 92, the second AP 22 transmits the scan signal generated in step 91 to the mobile node 1.

In step 93, the second AP 22 generates a network signal indicating that the mobile node 1 is moving from the first type network to the second type network.

In step 94, the second AP 22 transmits the network signal generated in step 93 to the mobile node 1.

10 is a flowchart of a method for performing a second handover in a mobile node according to an embodiment of the present invention.

Referring to FIG. 10, the method for performing the second handover in the mobile node 1 according to the present embodiment includes the following steps. The method of performing the second handover in the present mobile node 1 consists of the steps processed in time series in the apparatus for performing the second handover in the above-described mobile node 1. Therefore, even if omitted below, the description of the apparatus for performing the second handover in the mobile node 1 also applies to the method of performing the second handover in the mobile node 1.

In step 101, the mobile node 1 receives a signal from the second AP 22 connecting the mobile node 1 to the first type network.

In step 102, the mobile node 1 determines whether the signal received in step 101 is a scan signal indicating a cell managed by the second AP 22. That is, in step 102, the mobile node 1 determines whether the signal received from the second AP 22 is a beacon frame or probe response frame indicating the second BSS.

If it is determined in step 103 that the mobile node 1 is a scan signal, the mobile node 1 checks the cell information included in the signal.

In step 104, the mobile node 1 determines whether to change the cell in which the mobile node 1 is located based on the confirmation in step 103.

In step 105, the mobile node 1 selectively performs a handover according to the change of the cell where the mobile node 1 is located, based on the determination in step 104. That is, if it is determined in step 105 that the cell where the mobile node 1 is located is changed in step 104, the mobile node 1 performs a handover according to the change of the cell.

In step 106, the mobile node 1 determines whether the signal received in step 101 is a network signal indicating that the mobile node 1 is moving from the first type network to the second type network. That is, in step 106, the mobile node 1 determines with reference to the values recorded in the type field 8012 and the subtype field 8013 of the frame control field 801 of the management frame.

If it is determined in step 107 that the mobile node 1 is a network signal, the mobile node 1 enables the interface supporting the second type network. That is, when it is determined in step 107 that the mobile node 1 is a DID frame indicating a 3GPP standard based cellular network in step 106, the mobile node 1 enables an interface supporting the 3GPP standard based cellular network, and in step 106 the IEEE 802.16 standard If it is determined that the frame is a DID frame indicating a wireless metropolitan area network, the interface supporting the wireless metropolitan area network based on the IEEE 802.16 standard is enabled.

In step 108, the mobile node 1 determines whether to change the type of the network in which the mobile node 1 is located. That is, in step 108, the mobile node 1 determines the use of the enabled interface in step 107 with reference to the use environment of the interface supporting the first type network. In more detail, in step 108, the mobile node 1 may continue to use the interface supporting the first type network when the received signal strength is weak using the interface supporting the first type network. It decides that it is impossible and decides to use an interface supporting the second type network.

If it is determined in step 109 that the mobile node 1 decides to use an interface supporting the second type network in step 108, the mobile node 1 disables the interface supporting the first type network.

In step 1010, the mobile node 1 selectively performs a handover according to a change in the type of the network in which the mobile node 1 is located, based on the confirmation in step 106. That is, if it is determined in step 1010 that the mobile node 1 uses an interface supporting the second type network in step 108, the mobile node 1 stops using the disabled interface in step 109, and the mobile node 1 disables the enabled interface in step 107. Start using In this case, if it is determined in step 1010 that the mobile node 1 uses an interface supporting the 3GPP standard cellular network in step 108, the mobile node 1 changes the handover from the IEEE 802.11 based WLAN to the 3GPP standard cellular network. If it is determined in step 108 to use an interface supporting an IEEE 802.16 standard based wireless metropolitan area network, a handover is performed to change from an IEEE 802.11 based wireless LAN to an IEEE 802.16 standard based wireless metro area network.

In the above, embodiments of the mobile terminal 1 have been considered in consideration of a path from a wireless LAN based on an IEEE 802.11 standard to a 3GPP standard based cellular network or an IEEE 802.16 standard based wireless metropolitan area network. However, embodiments in which the mobile node considers a path different from the above-described paths may be sufficiently implemented by those skilled in the art based on the above-described technology. For example, embodiments considering the path to move from a 3GPP standard based cellular network or an IEEE 802.16 standard based wireless metropolitan area network to a wireless LAN based on IEEE 802.11 standard can be sufficiently implemented. However, at this time, the mobile node will be informed that the mobile node is moving to a new network using a frame format conforming to the 3GPP standard or the IEEE 802.16 standard.

Meanwhile, the above-described embodiments of the present invention can be written as a program that can be executed in a computer, and can be implemented in a general-purpose digital computer that operates the program using a computer-readable recording medium.

The computer-readable recording medium may be a magnetic storage medium (for example, a ROM, a floppy disk, a hard disk, etc.), an optical reading medium (for example, a CD-ROM, DVD, etc.) and a carrier wave (for example, the Internet). Storage medium).

So far I looked at the center of the preferred embodiment for the present invention. Those skilled in the art will appreciate that the present invention can be implemented in a modified form without departing from the essential features of the present invention. Therefore, the disclosed embodiments should be considered in descriptive sense only and not for purposes of limitation. The scope of the present invention is shown in the appended claims rather than the foregoing description, and all differences within the scope will be construed as being included in the present invention.

1 is a diagram illustrating a first communication environment to which preferred embodiments of the present invention are applied.

2 is a diagram illustrating a second communication environment to which preferred embodiments of the present invention are applied.

3 is a block diagram of an apparatus for performing first handover according to an embodiment of the present invention.

4 is a diagram illustrating a format of a beacon frame and a probe response frame according to an embodiment of the present invention.

5 is a flowchart of a method for performing first handover at an access point according to an exemplary embodiment of the present invention.

6 is a flowchart of a first handover method performed in a mobile node according to an embodiment of the present invention.

7 is a block diagram of an apparatus for performing a second handover according to an embodiment of the present invention.

8 is a diagram illustrating a format of a domain identifier (DID) frame according to an embodiment of the present invention.

9 is a flowchart of a method for performing a second handover in an access point according to an embodiment of the present invention.

10 is a flowchart of a method for performing a second handover in a mobile node according to an embodiment of the present invention.

Claims (16)

A method for performing handover in a mobile node moving between heterogeneous networks, (a) confirming whether the signal received from the node connecting the mobile node to the first type network includes network information indicating that the mobile node is moving from the first type network to the second type network; (b) if it is determined in step (a) that the network information is included, enabling an interface supporting the second type of network; And and (c) selectively performing a handover according to a change of the type of a network in which the mobile node is located by using the enabled interface. The method of claim 1, Determining use of an interface supporting the second type network by referring to a usage environment of the interface supporting the first type network; In step (c), if it is determined to use an interface supporting the second type of network, the device performs the handover. The method of claim 1, (d) determining whether the signal received from the node is a signal indicating a cell managed by the node; Step (c) is characterized in that to perform a handover according to the change of the cell where the mobile node is located based on the determination in step (d). The method of claim 1, The first type network is a wireless LAN based on IEEE 802.11 standards, and the second type network is a 3GPP standard based cellular network or an IEEE 802.16 based wireless metropolitan area network. The method of claim 1, Wherein the information is recorded in a pending field of a performance information field of a frame body field of a beacon frame or probe response frame according to the IEEE 802.11 standard. An apparatus for performing handover in a mobile node moving between heterogeneous networks, A network information checking unit for confirming whether a signal received from a node connecting the mobile node to the first type network includes network information indicating that the mobile node is moving from the first type network to the second type network ; An interface enable unit configured to enable an interface supporting the second type network when the network information check unit determines that the network information is included; And And a handover performer configured to selectively perform a handover according to a change in the type of a network in which the mobile node is located by using an interface enabled by the interface enabler. The method of claim 6, And a network change determiner configured to determine the use of the interface supporting the second type network by referring to the use environment of the interface supporting the first type network. The handover performer performs the handover when the network change determiner determines to use an interface supporting the second type network. A method for performing handover in a mobile node moving between heterogeneous networks, (a) determining whether the signal received from the node connecting the mobile node to the first type network is a network signal indicating that the mobile node is moving from the first type network to the second type network; (b) if it is determined in step (a) that the network signal is enabled, enabling an interface supporting the second type network; And and (c) selectively performing a handover according to a change of the type of a network in which the mobile node is located by using the enabled interface. The method of claim 8, Determining use of an interface supporting the second type network by referring to a usage environment of the interface supporting the first type network; The step (c), if it is determined to use an interface supporting the second type of network, performing the handover. The method of claim 8, (d) determining whether the signal received from the node is a scan signal indicating a cell managed by the node; Step (c) is characterized in that to perform a handover according to the change of the cell where the mobile node is located based on the determination in step (d). The method of claim 10, The first type network is a wireless LAN based on IEEE 802.11 standards, and the second type network is a 3GPP standard based cellular network or an IEEE 802.16 based wireless metropolitan area network. The method of claim 10, And checking the network signal by referring to a value recorded in a subtype field of a frame control field of a management frame according to the IEEE 802.11 standard. An apparatus for performing handover in a mobile node moving between heterogeneous networks, A network signal discriminating unit for determining whether the signal received from the node connecting the mobile node to the first type network is a network signal indicating that the mobile node is moving from the first type network to the second type network; An interface enable unit configured to enable an interface supporting the second type network when it is determined that the network signal is the network signal; And And a handover performer configured to selectively perform a handover according to a change in the type of a network in which the mobile node is located by using an interface enabled by the interface enabler. The method of claim 13, And a network change determiner configured to determine the use of the interface supporting the second type network by referring to the use environment of the interface supporting the first type network. The handover performer performs the handover when the network change determiner determines to use an interface supporting the second type network. A computer-readable recording medium having recorded thereon a program for executing the method of any one of claims 1 to 5. A computer-readable recording medium having recorded thereon a program for executing the method of claim 8 on a computer.

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