KR20060040463A - Apparatus and method of handovver on cellular system using the heterogeneous wireless network - Google Patents

Abstract

The present invention is to ensure the mobility for the case that the terminal that can access the heterogeneous network access to the heterogeneous network to move between heterogeneous networks, the handover of the terminal is required in the heterogeneous network connected to each other through the tunnel In this case, the present invention relates to a handover apparatus and method in a heterogeneous network for establishing a new path required by handover using a tunnel.

Heterogeneous network, cellular network, wireless LAN, handover, tunnel, enhanced base transceiver system (eBTS), enhanced base station controller (eBSC)

Description

Device and method for handover in cellular communication system using heterogeneous wireless network {APPARATUS AND METHOD OF HANDOVVER ON CELLULAR SYSTEM USING THE HETEROGENEOUS WIRELESS NETWORK}             

1 is a view according to the present invention, a configuration diagram of a terminal including a wireless LAN interface and a cellular interface.

FIG. 2 is a diagram of a heterogeneous network with a tunnel established between a terminal and an enhanced Base Transceiver System (eBTS) of a cellular network.

3 is a block diagram of an enhanced access point (eAP) for performing tunnel setup with a terminal and tunnel setup with a cellular network, to which the present invention is applied;

4 is a diagram of handover due to movement of a terminal between a cellular network and a wireless LAN network in the heterogeneous network shown in FIG. 2;

5 is a configuration diagram of a heterogeneous network in which a tunnel is established between a terminal and an enhanced base station controller (eBSC).

FIG. 6A is a diagram illustrating a handover occurring when a terminal moves from a cellular network to a WLAN network in a heterogeneous network where a tunnel is established between the terminal and the eBSC. FIG.

FIG. 6B is a call flow diagram according to handover when there is no tunnel between the eAP of the WLAN and the eBSC of the cellular network in the handover in the case illustrated in FIG. 6A.

FIG. 6C is a call flow diagram according to handover when a tunnel exists between an eAP of a WLAN and an eBSC of a cellular network in the handover in the case illustrated in FIG. 6A.

FIG. 6D is a diagram of a protocol stack in a CDMA2000 1X data service, used in the handover shown in FIG. 6A. FIG.

FIG. 7A illustrates a handover occurring when a terminal moves from a WLAN network to a cellular network in a heterogeneous network where a tunnel is established between the terminal and the eBSC. FIG.

FIG. 7B is a call flow diagram according to handover in the case shown in FIG. 7A. FIG.

7C is a diagram of a protocol stack in the case of the handover shown in FIG. 7A.

8A is a diagram in which an MSC performs handover for a terminal moving between a cellular network and a WLAN network.

FIG. 8B is a call flow diagram according to handover when a terminal, which has received a voice service in a cellular area, moves to a WLAN area in FIG. 8A.

FIG. 8C is a call flow diagram according to handover when a terminal, which has received a voice service in a wireless LAN region, moves to a cellular region in FIG. 8A.

FIG. 9A illustrates a PDSN performing handover for a terminal moving between a cellular network and a wireless LAN network. FIG.

FIG. 8B is a protocol stack according to handover that occurs when a terminal, which has been provided data service in a cellular area, in FIG. 9A moves to a WLAN area.

FIG. 9B is a protocol stack for handover that occurs when a terminal, which has been provided data service in a WLAN area, in FIG. 9A moves to a cellular area.

FIG. 9C is a protocol stack for handover that occurs when a UE, which has been provided a service in a WLAN area in FIG. 9A, moves to a cellular area.

The present invention relates to a handover apparatus and method in a cellular communication system using a heterogeneous wireless network that guarantees mobility of a terminal receiving a cellular service by accessing a cellular system through a heterogeneous wireless network.

Recently, as the general trend of communication technology is ubiquitous, there is a need for a technology for interworking between various heterogeneous communication networks. However, it is difficult for heterogeneous networks to directly interwork because of using air sections of different frequencies. In order to solve this problem, a method of interworking heterogeneous networks using a tunneling technique, which connects a heterogeneous network using a cellular network and another technology by a tunnel, has been proposed. However, the existing heterogeneous network interworking method merely suggests the tunnel setup between the cellular network and the heterogeneous network, and the mobility of the terminal in the network of the terminal connected to the heterogeneous network using the tunnel. It does not provide a plan.

As such, the mobility of the terminal is not guaranteed, which is a big problem, especially in a wireless network that emphasizes the mobility of the terminal. Therefore, in order to efficiently perform interworking of heterogeneous networks, in order to ensure mobility of terminals, a method for allowing a terminal to freely move between different air technologies between heterogeneous networks is required.

Accordingly, an object of the present invention is to provide a handover apparatus and method in a cellular communication system using a heterogeneous wireless network capable of guaranteeing mobility of terminals between heterogeneous networks.

Another object of the present invention is to provide a handover apparatus and method in a cellular communication system using a heterogeneous wireless network capable of ensuring mobility of a terminal between different air in a heterogeneous network.

It is another object of the present invention to ensure mobility of a terminal in a heterogeneous network interworking by using two tunnels, a tunnel between an access point (AP) of a terminal and a WLAN network and a tunnel between an access point of a WLAN network and a cellular network. The present invention relates to a handover apparatus and method in a cellular communication system using a heterogeneous wireless network.

In order to achieve the above object, the present invention; A first network providing a radio resource using a first radio frequency band, a first device of a cellular network connected to the first network through a wired network, and establishing a first tunnel with the first network; Establish a first network and a second tunnel, access the cellular network through the first tunnel and the second tunnel, or access the cellular network using radio resources provided by the cellular network, and require handover When determined, the present invention proposes a handover apparatus in a cellular communication system using a heterogeneous wireless network, comprising: establishing a new path according to the handover and including a terminal connecting to the cellular network through the new path.

In addition, the present invention; In a heterogeneous network where a cellular network and a first network, which is a heterogeneous network, are connected through a tunnel established between a terminal and an eBTS of a cellular network, a terminal requesting a handover when it is determined that handover is necessary, and the terminal and the tunnel When the eBTS connected through the terminal is requested to establish a tunnel for handover from the terminal, the terminal establishes a first tunnel with the terminal and requests the eBTS to establish a second tunnel so that the terminal and the eBTS establish the first tunnel and the first tunnel. A handover device in a cellular communication system using a heterogeneous wireless network is characterized by including an eAP for connecting through two tunnels.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In describing the present invention, if it is determined that the detailed description of the related known function or configuration may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted.

The present invention relates to a handover apparatus and method for ensuring mobility of a terminal in a network interworking heterogeneous networks having different air technologies.

The heterogeneous network in the present invention is based on the premise that the cellular network and the heterogeneous network other than the cellular network are interworked through tunnels. In addition, the following description of the present invention will be made by taking a heterogeneous network in which cellular networks, in particular, CDMA20001x networks, and wireless LAN (IEEE 802.11) networks are interworked, for the sake of understanding thereof. Therefore, in the technology of the present invention, the heterogeneous network becomes a WLAN network, and the heterogeneous network becomes a network interworking with a cellular network and a WLAN network. However, the scope of application of the present invention is not limited to the case where the WLAN is a heterogeneous network, and may be applied to a case where a variety of networks such as Bluetooth and IEEE 802.16 WiMax are used as the heterogeneous network.

In addition, in the following description of the present invention, the term cellular area refers to an area where a terminal can access a cellular network using a cellular frequency, and the term WLAN area refers to a terminal that uses a WLAN frequency to connect to a WLAN network. Means the accessible area. In this case, the terminal in the WLAN area may be provided with a cellular service using the WLAN frequency by using a tunnel connected to the cellular network. The terminal connects to a base station system (BSS) of a cellular network in a cellular area and to an access point (hereinafter referred to as "AP") in a wireless LAN area. The WLAN area and the cellular area may overlap each other. In general, the cellular region may be divided into different cellular regions depending on which base station (Base Transceiver System (hereinafter referred to as BTS)) is the area governed by. In addition, the WLAN area may be divided into different WLAN areas according to whether the AP manages the area. That is, the cellular area under the control of different base stations becomes a different cellular area, and the wireless LAN area under the control of different APs becomes a different wireless LAN area. Handover may occur in all cases where the UE moves between the different cellular regions, between different WLAN regions, and between WLAN regions and cellular regions. Here, the handover according to the movement of the terminal between the cellular regions is the same as the handover in the conventional cellular network.

On the other hand, the terminal to which the present invention is applied should be able to access the network in the wireless LAN area, it must include at least the WLAN interface function. First, a terminal to which the present invention can be applied will be described with reference to FIG. 1.

1 is a diagram of a terminal including a wireless LAN interface and a cellular interface according to the present invention.

The terminal 100 illustrated in FIG. 1 may set a wireless link using the wireless LAN interface module 102 in a wireless LAN area, and set a wireless link using a cellular frequency in a cellular area. Since the terminal 100 is capable of establishing a wireless link in both areas, the terminal 100 enables handover between two networks when moving between the WLAN area and the cellular area.

As shown in FIG. 1, the terminal 100 includes a wireless LAN interface module 102, a tunnel manager 104, a call processor 106, a cellular interface module 108, and a memory 110. Herein, the WLAN interface module 102 receives radio resources provided from a WLAN network using a WLAN dedicated frequency band to communicate with the WLAN. The tunnel manager 104 establishes and manages a tunnel with a cellular network connected to the WLAN network using a radio resource provided from the WLAN network through the WLAN interface module 102. The call processing unit 106 accesses the cellular network through the tunnel established through the tunnel management unit 104 to perform call processing. The cellular interface module 108 allocates radio resources provided from the cellular network using a cellular dedicated frequency band to communicate with the cellular network. The memory 110 stores tunnel setting information.

In addition, the terminal 100 should be able to perform a function for handover. The handover function performed by the terminal 100 includes a function for determining whether a handover is required and a function for requesting a handover when it is determined that the handover is necessary. In general, the terminal 100 determines that handover is necessary when the strength of a signal received through an existing path becomes less than a predetermined threshold. Of course, at this time, the terminal 100 should be able to receive a signal through another path, the strength of which is greater than the signal received through the existing path. The handover of the terminal 100 refers to a process of receiving a communication service through the other path instead of the existing path.

The terminal mentioned below refers to a terminal capable of connecting to both a WLAN network and a cellular network and capable of handover, as shown in FIG. 1. Therefore, hereinafter, a separate description for the terminal 100 will be omitted.

Hereinafter, the present invention relates to a handover in a heterogeneous network in which two networks are interworked by establishing a tunnel between a terminal and a cellular network. In this case, the terminal may establish a tunnel between the BSC or the base station controller (hereinafter, referred to as a "BSC") of the cellular network, and receive a cellular service through the established tunnel. Meanwhile, a BTS or BSC that can establish a tunnel between a terminal connected through an AP of a wireless LAN, which is used in the present invention, is specifically referred to as an enhanced BTS (hereinafter referred to as an eBTS) or an improved base station controller ( On the other hand, eBTS and eBSC do not perform the function of allocating radio resources using cellular frequency, unlike BTS or BSC of a normal cellular network, which is connected to eBTS or eBSC. This is because the terminals are terminals that are allocated a WLAN frequency from the AP in the WLAN region.

Hereinafter, the present invention will be largely divided into a handover in a heterogeneous network in which a tunnel is established between a terminal and an eBTS and a handover in a heterogeneous network in which a tunnel is established between a terminal and an eBSC. In describing the present invention, detailed descriptions of basic technical matters of the cellular network and the wireless LAN network, which are not directly related to the present invention, will be omitted.

First, a handover apparatus and method in a heterogeneous network in which a tunnel is established between a terminal and an eBTS will be described.

2 is a diagram of a heterogeneous network in which a tunnel is established between a terminal and an eBTS.

As shown in FIG. 2, the heterogeneous network according to the present invention includes a terminal 100, an enhanced AP (hereinafter referred to as an "eAP") 200, a router or a switch (hereinafter referred to only as a router) ( 202, gateway 204, and eBTS 206. Here, the eAP 200 has a function of establishing a tunnel with the terminal 100 and the eBTS 206 or the eBSC, in addition to the existing function of performing wireless communication with the terminal 100 using a wireless LAN frequency. The router 202 connects the eAP 200 to an external network. The gateway 204 connects the eAP 200 to an external network such as the Internet through the router 202. These components are the components corresponding to the WLAN network.

The eBTS 206 of the cellular network establishes a tunnel to the eAP 200 of the WLAN area in which the terminal 100 is located in order to provide cellular service to the UE 100 in the WLAN area. At this time, the eBTS 206 is connected to the gateway 204 via a wired network, and establishes a tunnel to the eAP 200 of the WLAN network through the wired network. The eAP 200 having a tunnel established with the eBTS 206 enables the eBTS 206 to provide a cellular service to the terminal 100 by establishing a tunnel with the terminal 100 to which the eBTS 206 communicates.

Meanwhile, as shown in FIG. 2, the eBTS 206 is connected to the Packet Data Switched Network (PDSN) 212 or the Mobile Switching Center (MSC) 214 through the BSC 210. The PDSN 212 is connected to the Internet to provide data communication to the terminal 100. The MSC 214 is connected to a public switched telephone network (PSTN) to provide voice communication to the terminal 100. PDSN 212 and MSC 214 perform exchange functions for data communication and voice communication, respectively, of the cellular system.

The eBTS 206 has a function of establishing and managing a wireless link using the terminal 100 managed by the mobile station and a cellular frequency, and performing a service for the terminal 100 connected through the wireless LAN frequency. Have That is, the eBTS 206 may transmit data transmitted from the terminal 100 connected through the tunnel in the WLAN area to the MSC 214 or the PDSN 212 through the BSC 210. In this case, data and signaling transmission between the BSC 210 and the eBTS 206 may be performed through a standard (for example, Abis) or an internal definition method (IPC: Inter Processor Communication) of each equipment company. The eBTS 206 receives data for cellular service from the BSC 210, and transmits the terminal 100 using a tunnel in which the received data is preset. In addition, the eBTS 206 transmits the data received from the terminal 100 through the tunnel to the BSC 210 through Abis or a separate IPC.

On the other hand, the eBTS 206 operates similarly to the other BTSs 208 to enable the BSC 210 to recognize itself as other BTSs 208.

First, a tunnel setup process between the terminal 100 and the eBTS 206 in a heterogeneous network having such a configuration will be described. The tunnel between the terminal 100 and the eBTS 206 may be divided into two tunnels, a tunnel established between the terminal 100 and the eAP 200 and a tunnel established between the eAP 200 and the eBTS 206.

When the eAP 200 receives a tunnel setup request from the terminal 100 to the eBTS 206, the eAP 200 establishes a tunnel with the terminal 100 requesting the tunnel setup, and the eBTS 206 with which the terminal 100 intends to communicate. ) To set up the tunnel. Through this, a tunnel is established between the terminal 100 and the eBTS 206. In addition, when the eAP 200 receives a tunnel setup request from the eBTS 206 to the terminal 100, the eAP 200 sets up a tunnel with the eBTS 206 that has requested the tunnel setup, and the eBTS 206 communicates with the terminal ( Ask 100 to set up the tunnel. That is, the terminal 100 and the eBTS 206 can establish a tunnel with the eBTS 206 or the terminal 100 to communicate with each other through the tunnel setup with the eAP 200.

The configuration of the eAP 200 for performing tunnel setup with the terminal 100 and the eBTS 206 will be described with reference to the accompanying drawings.

3 is a configuration diagram of an eAP.

As shown in FIG. 3, the eAP 200 includes a wireless LAN interface module 300, an IP network interface module 306, a tunnel manager 302, a call processor 304, and a memory 308. . The WLAN interface module 300 establishes a radio link with the terminal 100 by allocating a radio resource provided from the WLAN using a WLAN dedicated frequency band. The IP network interface module 306 communicates with the IP network. The tunnel manager 302 establishes a tunnel with the terminal 100 through a wireless link established by the WLAN interface module 300 and tunnels with the eBTS 206 through a wired network connected by the IP network interface module 104. Set up and manage each set tunnel. The call processing unit 304 performs call processing so that the terminal 100 accesses the eBTS 206 or the eBSC of the cellular network through each tunnel established through the tunnel manager 302. The memory 308 stores tunnel setting information.

Next, the tunnel setup between the terminal 100 and the eAP 200 and the tunnel setup between the eAP 200 and the eBTS 206 will be described. First, the tunnel setup between the terminal 100 and the eAP 200 will be described.

Tunnel setting may be manually inputted by the operator in the terminal 100 and the access point 200, or may be set automatically. Here, the process of automatic setting will be described in detail.

Various embodiments may be implemented according to a method for establishing a tunnel between the terminal 100 and the eAP 200. Here, an embodiment using a MAC (Media Access Control, MAC) address, an embodiment using an IP address, and an embodiment using both an IP address and a UDP (User Datagram Protocol) port number will be described. A description will be given of an embodiment of establishing a tunnel between the terminal 100 and the eAP 200 using the MAC address as follows.

The terminal 100 and the eAP 200 may communicate with each other in the MAC layer without the help of another network. Therefore, the eAP 200 and the terminal 100 can know each other's MAC address. When the terminal 100 and the eAP 200 pre-set whether the tunnel is established or not, the tunnel is set using the respective MAC address without a separate message. Otherwise, when the terminal 100 sends a tunnel connection establishment request to the eAP 200, the eAP 200 transmits a tunnel connection acceptance message to the terminal 100. Thereafter, the eAP 200 transmits all data received from the terminal 100 in which the tunnel is established to the eBTS 206 or all data received from the eBTS 206 to the terminal 100.

The detailed description of the embodiment of setting the tunnel using the IP address and the embodiment of setting the tunnel using the UDP port number will be omitted.

Next, the tunnel setup between the eAP 200 and the eBTS 206 will be described.

The message for requesting the tunnel establishment may be transmitted by the eAP 200 to the eBTS 206. The eAP 200 may select the eBSC 300 to request tunnel establishment through various methods. As an example, the eAP 200 may query a Domain Name Server (DNS) using a DNS query to find an IP address of the eBSC 300. The eAP 200 finds the IP address of the eBTS 206 to establish the tunnel, and then transmits a message requesting the tunneling setup to the corresponding eBTS 206. The message may include an ID (IP address, MAC address, etc.) of the eAP 200 and a user ID (eg, a network access identifier (NAI) or an International Mobile Subscriber Identity (IMSI)). signaling, CS data, PS signaling, PS data, other information, etc.) may be included.

When the eBTS 206 receives a message for requesting tunnel establishment from the eAP 200, the eBTS 206 transmits a message including BTS related information such as a Cell ID through a source port number of the corresponding eAP 200. This completes the UDP tunnel between the eAP 200 and the eBTS 300 and subsequently exchanges the necessary information using the tunnel.

However, in the heterogeneous network connected through the tunnel as described above, the terminal 100 may move from one network to another heterogeneous network. In this case, the system needs to be handed over. The handover process may be roughly divided into a process of detecting that the UE has moved from an existing area to another area and a process of setting a new communication path for communication after the movement. The handover function, that is, the handover decision and the handover process according to the decision are performed in the BSC. However, the handover request is generally made by the terminal.

4 is a diagram of handover due to movement of a terminal between a cellular network and a wireless LAN network.

4 illustrates a handover, in particular, when the terminal 100 moves from the cellular area to the wireless LAN area. The handover in this case can be handled in the same way as the inter-BTS handover with the BSC 210 as an anchor, except that the new path setup after the handover involves the tunnel setup process. This is because the BSC 210 may communicate with the eBTS 206 in the same manner as the BTS 208 in a heterogeneous network where a tunnel is established between the terminal 100 and the eBTS 206. In this case, the terminal 100 and the eBTS 206 establish a tunnel for the eAP 200, respectively. Since the tunnel configuration has been described above, a detailed description thereof will be omitted here. That is, the terminal 100 moves to the wireless LAN area that the new eAP 200 manages. If there is a need to create a new route through the eAP 200 for handover, it requests a new eAP 200 to establish a tunnel. When the eAP 200 receives a tunnel setting request from the terminal 100, the terminal 100 and the eBTS 206 transmit and receive data to each other by performing tunnel setting with the eBTS 206 to communicate with. To help.

That is, handover in a heterogeneous network in which a tunnel is established between the terminal 100 and the eBTS 206 may be processed in the same manner as handover of a cellular network. However, it should be noted that the generation of a new path for transmitting and receiving data after handover includes a tunnel setup process between the terminal 100 and the eAP 200 and the eAP 200 and the eBTS 206.

Next, a handover in a heterogeneous network in which a tunnel is established between the terminal 100 and the eBSC 500 will be described. First, a tunnel setting between the terminal 100 and the eBSC 500 will be described with reference to the accompanying drawings.

5 is a configuration diagram of a heterogeneous network in which a tunnel is established between a terminal and an eBSC.

The eBSC 500 of FIG. 5 transmits data transmitted / received with the terminal 100 connected through the tunnel to the MSC 214 or the PDSN 212. The eBSC 100 performs a function of controlling base stations (including both eBTS and BTS) managed by the eBSC 100, and performs a cellular communication service for the terminal 100 connected through a wireless LAN. That is, the eBSC 500 is a tunnel setup function with the terminal 100 to be connected via the wireless LAN to the function of the BSC is added, it can perform the same function as the existing BSC. That is, the eBSC 500 may also perform a handover function to determine whether to handover and process the handover according to the result.

For description of other components of FIG. 5, refer to the description of FIG. 2. Note that the eBTS 206 is not needed when the eBSC 500 is used as shown in FIG. 5.

The tunnel between the terminal 100 and the eBSC 500 may be divided into a tunnel between the terminal 100 and the eAP 200 and a tunnel between the eAP 200 and the eBSC 500.

See FIG. 3 for a description of the tunnel setup between the terminal 100 and the eAP 200.

The tunnel setup between the eAP 200 and the eBSC 500 may be performed as follows.

When the eAP 200 establishes a UDP tunnel to the eBSC 300, the eAP 200 transmits a message requesting the tunnel setup to the eBSC 300 using the IP address of the eBSC 300 stored therein. The message may include an ID (IP address, MAC address, etc.) of the eAP 200 and a user ID (for example, a network access identifier (NAI) or an international mobile subscriber identity (IMSI)), and the type of data (CS). signaling, CS data, PS signaling, PS data, other information, etc.) may also be included.

Receiving a message requesting the tunnel from the access point 200 eBSC (300) periodically transmits a message containing BSC-related information, such as Cell ID through the source port number of the corresponding access point (200). This completes the UDP tunnel between the access point 200 and the eBSC 300 and subsequently exchanges necessary information using this tunnel.

Next, a handover in a heterogeneous network in which a tunnel is established between the terminal 100 and the eBSC 500 will be described.

Handover in a heterogeneous network in which a tunnel is established between the terminal 100 and the eBSC 500 is divided into three cases, a handover between BSCs, a handover at the MSC 214, and a handover at the PDSN 212. Can be explained.

First, the first inter-BSC handover will be described.

The inter-BSC handover can be divided into two cases, which occur when the terminal 100 moves from the cellular network to the WLAN network and when the terminal 100 occurs due to the movement from the WLAN network to the cellular network. have.

FIG. 6A illustrates a handover that occurs when a UE moves from a cellular network to a WLAN network in a heterogeneous network where a tunnel is established between the UE and the eBSC.

As shown in FIG. 6A, the terminal 100, which has received communication service from the cellular network through a traffic path connected through the BTS 208 and the BSC 210 in the cellular network area, moves to the WLAN area and then eAPs. The communication service is provided through a new traffic path connected through the 200, the router 202, the gateway 204, the eBSC 500, and the BSC 210. In this case, the terminal 100 must perform tunnel setup with the eBSC 500 to establish a new traffic path. This tunnel setting is made through the eAP (200). That is, the terminal 100 requests the eAP 200 to establish a tunnel, and the eAP 200 that receives the request establishes a tunnel with the corresponding eBSC 500 to establish a tunnel between the terminal 100 and the eBSC 500. To be set.

Meanwhile, in the handover illustrated in FIG. 6A, the BSC 210 operating in the existing cellular network becomes an anchor. Since the tunnel is set up between the terminal 100 and the eBSC 500, the BSC 210 is performed. EBSC 500 operates like other BSCs. Therefore, call flow of inter-BSC handover is the same as the existing cellular standard.

FIG. 6B is a call flow diagram according to handover when there is no tunnel between the eAP of the WLAN and the eBSC of the cellular network in the handover in FIG. A.

When the terminal 100 wants to generate a path that is connected to the new eBSC 500 due to handover, the path is established between the terminal 100 and the eAP 200 and the tunnel between the eAP 200 and the eBSC 500. This can be done through tunnel setup. However, there may be a case where a tunnel is previously established between the eAP 200 and the eBSC 500, or a case where a tunnel is not established. 6B is a call flow diagram according to handover when there is no existing tunnel between the eAP 200 and the eBSC 500.

In FIG. 6B, since there is no tunnel between the terminal 100 and the eBSC 500, in order to establish a new path for handover, the tunnel setup between the terminal 100 and the eAP 200 and the eAP 200 and the eBSC 500 are performed. All tunnel settings must be made.

In 600 of FIG. 6B, the terminal 100 recognizes a time point of handover by detecting that the area in which the terminal is located is changed. In this case, the terminal may detect that the strength of the signal received from the BTS 208 is weakened and detect that the area is changed. When the terminal 100 recognizes the time of handover, the terminal 100 connects to the connection establishment 602 for the eAP 200 and the dynamic host configuration protocol (DHCP) for the gateway 204. IP address acquisition 604 and tunnel establishment 606 targeting a newly connected eAP 200 are performed.

The eAP 200 that has received the tunnel setup request for handover from the terminal 100 requests tunnel setup from the corresponding eBSC 500 to perform tunnel setup with the eBSC 500 (608). This establishes a tunnel between the terminal 100 and the eBSC 500, and generates a path to be used for data transmission of the handover call. Here, the tunnel setup process is included in the path establishment for the handover because the present invention is applied to a heterogeneous network interworking using a tunnel.

When the tunnel setup is made, the terminal 100 transmits a message requesting a handover to the new BSC, that is, the eBSC 500, to the old BSC 210 (610). This message may be delivered using a power control message. This message also contains the information of the eBSC 500 to be newly routed. Thereafter, handover is performed between the old BSC BSC 210 and the new BSC eBSC 500 through the exchange 612 of a handover request message and a response message. Meanwhile, after handover, the A7 protocol, which is a CDMA2000 1X standard for transmitting data between BSCs, may be used for data transmission between the BSC 210 and the cBSC 500.

Meanwhile, an existing tunnel may exist between the eAP 200 and the eBSC 500. In this case, a tunnel setting process between the eAP 200 and the eBSC 500 may be omitted.

FIG. 6C is a call flow diagram according to handover when there is a tunnel between an eAP of a wireless LAN and an eBSC of a cellular network in the handover in FIG. 6A.

In FIG. 6C, the tunnel setting process 608 between the eAP 200 and the eBSC 500 of FIG. 6B is omitted. Therefore, the handover process in this case can be performed as follows.

In 600 of FIG. 6B, the terminal 100 recognizes a time point of handover by detecting that the area in which the terminal is located is changed. When the terminal 100 recognizes the time of handover, the terminal 100 connects to the connection establishment 602 for the eAP 200 and the dynamic host configuration protocol (DHCP) for the gateway 204. IP address acquisition 604 and tunnel establishment 606 targeting a newly connected eAP 200 are performed.

The eAP 200, which has been requested to set up a tunnel for handover from the terminal 100, uses an existing tunnel without a separate tunnel setup process with the eBSC 500.

This establishes a tunnel between the terminal 100 and the eBSC 500, and generates a path to be used for data transmission of the handover call. Subsequent processes are as described in FIG. 6B.

FIG. 6D is a diagram of a protocol stack in a CDMA2000 1X data service, used in the handover shown in FIG. 6A.

Referring to FIG. 56, the BSC 210 used by the terminal 100 before the handover and used by the terminal 100 to access the cellular network is connected to the WLAN through the handover. The inter-BSC handover path is established between the eBSCs 500 used to verify that traffic is delivered. 6D illustrates a case in which a generic routing encapsulation (GRE) tunnel is established between the eAP 200 and the eBSC 500. On the other hand, the eAP 200 looks at the UDP port number sent by the terminal 100 and classifies the data to be transmitted to the GRE tunnel.

FIG. 7A illustrates a handover that occurs when a UE moves from a WLAN network to a cellular network in a heterogeneous network where a tunnel is established between the UE and the eBSC.

As shown in FIG. 7A, a terminal 100 connected to a cellular network through an eAP 200, a router 202, a gateway 204, and an eBSC 500 in a wireless LAN area and receiving a communication service is a cellular network. After moving to the area, a communication service is provided through a new traffic path connected through the BTS 208, the BSC 210, and the eBSC 500. In this case, the tunnel setup for creating a new traffic path is not required. In the case of FIG. 7A, the eBSC 500 becomes an anchor to perform handoff between the BSC 210 and the BSC.

FIG. 7B is a call flow diagram according to handover in the case shown in FIG. 7A.

If the terminal 100 recognizes the handover time (700), it requests the handover to the eBSC (500) (702). When the eBSC 500 receives the handover request, the eBSC 500 exchanges a BSS 750 handover request message and a response message to which a path with the terminal 100 is newly set, and instructs the terminal 100 to perform the handover. Send a signal (708). That is, in the case of a handover in which the terminal 100 moves from the WLAN area to the cellular area, a tunnel setting process for path generation is not performed.

FIG. 7C is a diagram of a protocol stack according to the case of the handover shown in FIG. 7A.

Next, the handover in the MSC 214, which is the second case of the handover in the heterogeneous network where the tunnel is established between the terminal 100 and the eBSC 500, will be described. This case is a handover when the terminal 100 is connected to the PSTN through the MSC 214 to receive a voice service.

8A is a diagram in which an MSC performs handover for a terminal moving between a cellular network and a WLAN network.

As shown in FIG. 8A, the terminal 100 may be handed over between a path connected to the MSC 214 through the eBSC 500 and a path connected to the MSC 214 through the BSC 210.

The call flow diagram during handover of FIGS. 8B and 8C to which the handover process is attached will be described below.

8B is a call flow diagram according to handover when a terminal, which has been provided with a voice service in a cellular region, moves to a WLAN region.

When the terminal 100 connected to the BSC 210 and received the communication service recognizes the movement of its area by detecting the weakness of the signal received from the BTS 208 (800), the cellular area is connected to the eBSC 500. Request a handover to. The handover request for the eBSC 500 of the terminal 100 includes connection establishment 802 with the eAP 200, IP address allocation 804 from the gateway 204, tunnel establishment 806 with the eAP 200, and the like. Tunnel establishment 808 processes between the eAP 200 and the eBSC 500.

When the tunnel setup with the eBSC 500 is established, the terminal 100 transmits a message requesting a handover to the eBSC 500 to the BSC 210 using the power control message (810). This message is sent 812 to the MSC 214 via the BSC 210. Upon receiving this message, the MSC 214 transmits a handover request message and a response message to the eBSC 500 to be connected to the terminal 100 after the handover (814). When the MSC 214 receives the response message accepting the handover from the eBSC 500, the MSC 214 transmits an indication signal to the terminal 100 to transmit data using the new path according to the handover (816).

8C is a call flow diagram according to handover when a terminal, which has received a voice service in a WLAN area, moves to a cellular area.

Finally, a description will be given of the handover in the PDSN 212, which is the third case of handover in a heterogeneous network where a tunnel is established between the terminal 100 and the eBSC 500. In this case, the handover occurs while the terminal 100 receives the data service. Here, the base station system (BSS) 750 is a general term for the BTS 208 and the BSC 210.

FIG. 9A is a diagram of a PDSN performing handover for a terminal moving between a cellular network and a WLAN network.

The terminal 100 may be handed over between a path connected to the PDSN 212 through the eBSC 500 and a path connected to the PDSN through the BSC 210.

FIG. 9B is a protocol stack according to a handover caused by a UE having received data service in a cellular area from FIG. 9 moving to a wireless fso area, and FIG. 9C is a cellular area of a UE provided with a service in a WLAN area in FIG. 9A. Protocol stack for handover that occurs by moving to.

A separate description of these protocol stacks is omitted.

On the other hand, a terminal including only the wireless LAN interface function without the cellular interface function can be connected to the network in the wireless LAN area. However, this type of terminal cannot be connected to the network in the cellular area, and thus is not suitable for the description of the present invention, which is intended to describe the handover for moving between the wireless LAN area and the cellular area. However, when the cellular service is provided in the wireless LAN area using the terminal of this type, the terminal may be supported for handover when moving from one wireless LAN area to another wireless LAN area. In a network capable of receiving cellular service in a wireless LAN area, the terminal may receive handover according to movement between different wireless LAN areas through the application of the present invention.

On the other hand, the present invention is not limited to a heterogeneous network in which a cellular network and a wireless LAN network are interworked, and may be applied to a heterogeneous network in which a heterogeneous network other than a wireless LAN network is interworked with a cellular network.

By applying the handover apparatus and method for a terminal moving between heterogeneous networks according to the present invention it is possible to ensure the mobility of the terminal in the heterogeneous network.

Claims (19)

A first network for providing radio resources using a first radio frequency band; A first device of a cellular network connected to the first network via a wired network to establish a first tunnel with the first network; Establish a second tunnel with the first network, access the cellular network through the first tunnel and the second tunnel, or access the cellular network using radio resources provided by the cellular network, The handover device in a cellular communication system using a heterogeneous wireless network comprising a terminal for establishing a new path according to the handover and accessing the cellular network through the new path if it is determined necessary. 2. The handover apparatus of claim 1, wherein the terminal determines that handover is necessary when the strength of a received signal falls below a predetermined threshold. The handover apparatus of claim 1, wherein the terminal uses a heterogeneous wireless network for establishing the second tunnel for an enhanced access point (eAP) of the first network. The handover apparatus of claim 1, wherein the first apparatus uses a heterogeneous wireless network that establishes the first tunnel for an eAP of the first network. The method of claim 1, wherein the first tunnel or the second tunnel uses a heterogeneous wireless network configured using one of a user datagram protocol (UDP), a generic routing encapsulation (GRE), and a GPRS transfer protocol (GTP). Handover device in cellular communication system. The handover apparatus of claim 1, wherein the terminal releases an existing route after completion of generating the new route. The method of claim 1, wherein the terminal transmits a first message indicating that data is to be transmitted through the new path before transmitting data to a device of a new cellular network connected through the new path through the existing path. Handover device in a cellular communication system using a heterogeneous wireless network transmitting to the devices of the cellular network to which it is connected. 8. The handover apparatus of claim 7, wherein the first message is transmitted using a power control message. 8. The handover apparatus of claim 7, wherein the first message comprises information of the new path. The handover apparatus of claim 1, wherein the first apparatus is an enhanced base transceiver system (eBTS) or an enhanced base station controller (eBSC). . 2. The handover apparatus of claim 1, wherein the first network is one of an IEEE 802.11 wireless LAN network, a Bluetooth network, and an IEEE 802.16 WiMax. In the heterogeneous network to which the cellular network and the first network, which is a heterogeneous network, are connected through a tunnel established between the terminal and the eBTS of the cellular network, The terminal requesting the handover when it is determined that the handover is necessary; An eBTS connected to the terminal through a tunnel; Upon receiving a request for setting up a tunnel for handover from the terminal, establishing a first tunnel with the terminal and requesting the eBTS to establish a second tunnel to connect the terminal and the eBTS through the first tunnel and the second tunnel. Handover device in a cellular communication system using a heterogeneous wireless network including eAP. In a heterogeneous network in which a cellular network and a first network, which is a heterogeneous network, are connected through a tunnel established between a terminal and an eBSC of a cellular network. The terminal requesting the handover when it is determined that the handover is necessary; An eBSC connected to the terminal through a tunnel; Upon receiving a request for establishing a tunnel for handover from the terminal, establishing a first tunnel with the terminal and requesting the eBSC to establish a second tunnel so that the terminal and the eBSC are connected through the first tunnel and the second tunnel. Handover device in a cellular communication system using a heterogeneous wireless network including eAP. In a heterogeneous network in which a cellular network and a first network, which is a heterogeneous network, are connected through a tunnel, A first process of the terminal determining whether handover is necessary; If it is determined that handover is necessary, a second process of establishing a first tunnel with the first network to create a new path to be used for data transmission after the handover; A third process of establishing a second tunnel connecting the first network and the cellular network; And a fourth process of performing data transmission / reception with the cellular network through the generated new path including the first tunnel and the second tunnel. 15. The method of claim 14, further comprising a fourth step of releasing a path before handover. In the heterogeneous network to which the cellular network and the first network, which is a heterogeneous network, are connected through a tunnel established between the terminal and the eBTS of the cellular network, A first step in which the eBTS is requested to generate a new path for handover from a terminal through an eAP; A second process of performing a new path generation through tunnel establishment with the terminal; A handover method in a cellular communication system using a heterogeneous wireless network comprising a third process of performing data transmission and reception with the terminal through the new path. 17. The method of claim 16, wherein the new path comprises a first tunnel established between the terminal and the eAP and a second tunnel established between the eAP and the eBTS. In a heterogeneous network in which a cellular network and a first network, which is a heterogeneous network, are connected through a tunnel established between a terminal and an eBSC of a cellular network. A first step in which the eBSC is requested to generate a new path for handover from a terminal through an eAP; A second process of performing a new path generation through tunnel establishment with the terminal; A handover method in a cellular communication system using a heterogeneous wireless network comprising a third process of performing data transmission and reception with the terminal through the new path. 19. The method of claim 18, wherein the new path comprises a first tunnel established between the terminal and the eAP and a second tunnel established between the eAP and the eBSC.

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