KR20050079407A - Method for providing soft handover using communication state information in wireless internet system - Google Patents

Abstract

1. TECHNICAL FIELD OF THE INVENTION

The present invention relates to a soft handover method using communication status information in a wireless Internet system and a computer-readable recording medium having recorded thereon a program for realizing the method.

2. The technical problem to be solved by the invention

According to the present invention, when a mobile node (MN) moves from one subnet to another subnet in a wireless Internet system, it notifies a communication state information server and a counterpart node (CN) so that the counterpart node (CN) communicates with the communication state information server. A soft handover method using communication status information in a wireless Internet system and a program for realizing the method for recording a soft handover by allowing a binding update to be performed by a query / response with Its purpose is to provide a computer-readable recording medium.

3. Summary of the Solution of the Invention

The present invention provides a soft handover method using communication state information in a wireless Internet system, wherein a mobile node (MN) detects its own subnet movement and is assigned a mobile address (COA) from an external agent (FA). step; A movement notification step of the mobile node (MN) informing its movement by transmitting the assigned mobile address (COA) to a communication status information server; A mobile station for updating the location information of the mobile node MN using the mobile address COA received from the mobile node MN and notifying the counterpart node CN by the presence information server. Notification step; And a first binding update step of the counterpart node CN obtaining a current location information of the mobile node MN from the communication state information server and performing a binding update.

4. Important uses of the invention

The present invention is used in a wireless Internet service system.

Description

Soft handover method using communication status information in wireless internet system {METHOD FOR PROVIDING SOFT HANDOVER USING COMMUNICATION STATE INFORMATION IN WIRELESS INTERNET SYSTEM}

The present invention relates to a soft handover method using communication state information in a wireless Internet system, and a computer-readable recording medium having recorded thereon a program for realizing the method.

Mobile Internet Protocol (MIP) is a standard protocol for supporting the mobility of IP due to the movement of a terminal. The mobile Internet protocol (MIP) allows a user to use the Internet seamlessly even when the terminal moves out of the network area to another network. Protocol. That is, if any terminal physically changes its access location on the Internet, routing information related to the terminal is changed, and packets transmitted using the routing information before the change cannot be properly delivered. Mobile IP is to solve this problem.

In the Mobile IP Protocol (MIP), a mobile node registers its home address with a home agent (HA). When moving to an external network, a mobile node may call a COA (Care-Of Address) from a foreign agent (FA). It is based on a method of assigning a temporary IP address to a home agent (HA).

At this time, the mobile node is a terminal that changes the access point from one network or subnetwork to another network, and can communicate without changing its IP address. That is, a home agent (HA) of a home network that generates and maintains location information of a mobile node tunnels a packet transmitted to the mobile node and delivers the packet to an external agent currently registered with the mobile node. The Foreing Agent (FA) provides a routing service to a registered mobile node, and decapsulates and transmits data transmitted by being tunneled by the home agent of the mobile node to the mobile node. Here, tunneling refers to an environment (transport channel) in which an IP packet can be carried on another IP packet.

In addition, a care-of address (COA) is an address assigned to manage a mobile node in the external network when the mobile node is connected to an external network. This address will change again when the mobile node moves to another external network. That is, a care-of address (COA) is an address required when a home agent (HA) forwards a packet to a mobile node, and may be referred to as an address at the end of a tunnel. The transmitted packet is a care-of address ) Is finally passed to the mobile node.

On the other hand, the operation process of the mobile IP protocol is largely composed of three mechanisms: agent discovery, registration, and routing. The agent discovery process is performed by a mobile node in its current location. If the mobile node is out of the home link, the registration process is a process of obtaining its own care-of address (COA) when the mobile node leaves the home link. Home Agent). Looking at the operation of the mobile IP protocol (Mobile IP) in more detail with reference to Figure 1 and 2 as follows.

First, a Home Agent (HA) 13 and a Foreign Agent (FA) 12 periodically broadcast an Agent Advertisement (Advertisement) message to inform themselves of which network (102). If the mobile node (MN) 11 does not receive the Agent Advertisement message, it requests an external agent (FA) 12 to send an Agent Advertisement message through an Agent Solicitation message. It may also be 101.

On the other hand, when the mobile node (MN) 11 receives an agent advertisement message, it determines whether it is currently in the home network or in which external network. As a result of the determination, if the mobile node (MN) 11 is in a home network, it operates without a mobile service, and if the mobile node (MN) 11 moves to an external network, a care-of address (COA) is obtained (202, 203). Register with its home agent (HA) 13 (103, 104, 204, 205). If the mobile node (MN) 11 returns to the home network while the mobile node (MN) 11 is registered in the external network, the mobile node (MN) 11 registers with a registration request message and a registration reply. Deletes the information registered in the home agent (HA) (information registered as being in an external network) through the message. In this case, a care-of address (COA) may be determined by an agent advertisement message of a foreign agent (FA) or a dynamic host configuration protocol (DHCP).

Thereafter, the home agent (HA) 13 recognizes the network identifier of the mobile node (MN) 11 and registers the packet transmitted to the mobile node (MN) 11 by the mobile node (MN) 11. Tunneling to a care-of address (COA) (105, 206). At this time, the termination of the tunnel is either the foreign agent (FA) 12 or the mobile node (MN) 11. When the terminal is an external agent (FA) 12, the foreign agent (FA) 12 extracts and transmits a packet to be delivered to the mobile node (MN) 11 from packets received through various paths. In the packet transmission in the reverse direction, the foreign agent (FA) 12 acts as a router of the mobile node (MN) 11 and transmits directly to the destination without using tunneling.

On the other hand, in order for the counter node (CN) 14 to know the location of the mobile node (MN) 11, it exchanges packets with the mobile node (MN) 11 to determine the address of the mobile node (MN) 11, In this case, the binding information must be found to update the binding information (207). That is, the counterpart node 14 transmits data to the home agent 13 until the binding information of the mobile node MN 11 is updated, and changes the traffic path when the binding update is completed. (208).

However, in the conventional method as described above, when the counter node (CN) 14 transmits data to the mobile node (MN) 11, it passes through the home agent (HA) 13 and the foreign agent (FA) 12. Since triangular routing occurs, there is a problem that data transmission is delayed.

In addition, in the conventional method, when a handover occurs due to the movement of the mobile node (MN) 11, a new care-of address (COA) is informed to the external network router which previously belonged to, and the new node has a new care-of-care (COA). The binding information had to be updated by telling the binding information of Of Address). Therefore, in the conventional handover method, if the movement of the mobile node (MN) 11 occurs frequently, the update of binding information occurs frequently, resulting in loss of data and inefficiency of handover. there was.

The present invention has been proposed to solve the above problems, and when the mobile node (MN) is moved from one subnet to another subnet in a wireless Internet system to notify the communication status information server and the counterpart node (CN) Soft hand using communication status information in a wireless Internet system for allowing the counterpart node CN to perform a binding update by query / response with the communication status information server, so that a softer handover is performed. An object of the present invention is to provide an over method and a computer-readable recording medium having recorded thereon a program for realizing the method.

The method of the present invention for achieving the above object, in a soft handover method using communication state information in a wireless Internet system, the mobile node (MN) detects its own subnet movement and the mobile address from the foreign agent (FA) A mobile address assignment step of being assigned a COA; A movement notification step of the mobile node (MN) informing its movement by transmitting the assigned mobile address (COA) to a communication status information server; A mobile station for updating the location information of the mobile node MN using the mobile address COA received from the mobile node MN and notifying the counterpart node CN by the presence information server. Notification step; And a first binding update step of the counterpart node CN obtaining the current location information of the mobile node MN from the communication state information server and performing a binding update.

The method may further include a second binding update step of receiving a binding update signal from the mobile node (MN) by the home agent (HA), performing binding update accordingly, and returning a binding response. It features.

On the other hand, the present invention, the wireless Internet system having a processor, the mobile node (MN) detects the movement of its own subnet and a mobile address assignment function that is assigned a mobile address (COA) from the foreign agent (FA); A movement notification function of the mobile node (MN) informing its movement by transmitting the assigned movement address (COA) to a communication status information server; A mobile station for updating the location information of the mobile node MN using the mobile address COA received from the mobile node MN and notifying the counterpart node CN by the presence information server. Notification function; And a computer-readable recording program for realizing a first binding update function of obtaining the current position information of the mobile node MN by the counterpart node CN from the communication state information server and performing a binding update. Provide the medium.

In addition, the present invention records a program for further realizing a second binding update function in which a home agent HA receives a binding update signal from the mobile node MN, performs binding update accordingly, and returns a binding response. Provide a computer readable recording medium.

The above objects, features and advantages will become more apparent from the following detailed description taken in conjunction with the accompanying drawings. Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

3 is a diagram illustrating an embodiment of communication status information used in the present invention.

Presence information (Presence Information) is a function for informing the other party's online access state between users who want to communicate with each other, is defined in the IETF (Internet Engineering Task Force) RFC 2778. In the format of the presence information, as shown in FIG. 3, the current location of the user is stored in the communication address field 33 in the communication status information tuple 31, and the state ( status) field 32 stores the user's status, such as online, offline, on the go, on the job.

Meanwhile, a Presence Information server managing such Presence Information registers / maintains the current location of a user who is online and informs other users of the Presence Information, thereby enabling immediate communication service. . As shown in FIG. 4, an appropriate number may exist according to the number of subnets or nodes, and follow the same structure as that of a domain name system (DNS).

At this time, the address information for a specific subnet is retained by a specific Presence Information Server, and each Presence Information Server includes the IP of the mobile node based on the MAC address of the UE. The address (fixed) and the care-of address (COA) tuple of the movement are stored to correspond to each other.

On the other hand, the process of searching for an address in the communication information server (Presence Information) server, the counterpart node (CN) 14 of the mobile node (MN) 11 to the communication status information (Presence Information) server 43 to which it belongs; Begin by sending a query requesting location information. A query for requesting location information of the mobile node (MN) 11 is carried out by the mobile node (MN) 11 via a master communication status information server and a root communication status information server 41. It is transmitted to the communication status information (Presence Information) server 42 to which it belongs.

Then, the communication status information server 42 to which the mobile node (MN) 11 belongs responds to the master communication status information server and the root communication status information (Presence Information) in response to the location information query. The server 41 returns to the counter node 14 via the server 41. A soft handover method using communication state information in a wireless Internet system according to the present invention will be described in detail with reference to FIG. 5.

5 is a signal flow diagram of an embodiment of a soft handover method using communication status information in a wireless Internet system according to the present invention.

First, when the mobile node (MN) 51 moves from one subnet to another subnet, it requests an external agent (FA) 52 to transmit an agent advertisement message using an agent solicitation message. (501).

When the mobile node (MN) 51 receives an agent advertisement message from the foreign agent 52 (502) and detects that the mobile node has moved to the external network (502), the foreign agent (FA) After receiving a care-of address (COA) from the 52, it transmits it to the communication information server 53 to notify its movement. Then, the presence information server 53 updates the location information of the mobile node (MN) 51 and informs the counterpart node (CN) 55 of this (503).

Then, the counterpart node (CN) 55 obtains current location information of the mobile node (MN) 51 from the communication state information server 53 through the above-described location information query / response process (504). . Accordingly, the counterpart node (CN) 55 may perform a binding update from the position information COA of the changed mobile node (MN) 51 even if it does not receive a packet from the mobile node (MN) 51 (505). ). Thus, the first packet may be sent 506 directly to the mobile node (MN) 51 without tunneling.

Subsequently, packet transmission and reception using the routing header is performed between the mobile node (MN) 51 and the counterpart node (CN) 55 in the same manner as before (507).

Meanwhile, the mobile node (MN) 51 may continue communication with the home agent (HA) 54 after updating the location information of the communication state information server 53. Then, the packet transmitted while the counterpart node 55 performs the binding update may be delivered by tunneling. This is to minimize the loss of packets which may occur even if the binding update of the counterpart node (CN) 55 occurs momentarily.

The method of the present invention as described above may be implemented as a program and stored in a computer-readable recording medium (CD-ROM, RAM, ROM, floppy disk, hard disk, magneto-optical disk, etc.). Since this process can be easily implemented by those skilled in the art will not be described in more detail.

The present invention described above is capable of various substitutions, modifications, and changes without departing from the spirit of the present invention for those skilled in the art to which the present invention pertains. It is not limited by the drawings.

As described above, according to the present invention, when the mobile node MN moves from one subnet to another subnet in the wireless Internet system, the mobile node CN notifies the communication status information server and the counterpart node CN so that the counterpart node CN moves. Even if the binding update from the node MN is not performed, a care-of-address (COA) of the mobile node MN may be obtained by performing a query / response with the communication state information server, and the binding update may be performed. There is an effect that can improve the quality of service by making a softer handover.

In addition, according to the present invention, since the counterpart node CN does not have to bypass traffic through the home agent HA in order to obtain the binding information, it is possible to prevent deterioration of the quality of a voice call and the like. There is an effect that can additionally provide a location based service using the location information of the communication state information server.

1 is a signal flow diagram of an embodiment of a handover method in a wireless Internet system according to a conventional method.

2 is a diagram illustrating a handover method in a wireless Internet system according to a conventional method.

3 is a diagram illustrating an embodiment of communication status information used in the present invention.

4 is a diagram illustrating an embodiment of a communication status information server used in the present invention.

5 is a signal flow diagram of an embodiment of a soft handover method using communication status information in a wireless Internet system according to the present invention;

* Explanation of symbols on the main parts of the drawing

51: mobile node (MN) 52: foreign agent (FA)

53: Presence Information Server

54: home agent (HA) 55: partner node (CN)

Claims (6)

A soft handover method using communication status information in a wireless internet system, A mobile address assignment step of the mobile node MN detecting its own subnet movement and being assigned a mobile address COA from an external agent FA; A movement notification step of the mobile node (MN) informing its movement by transmitting the assigned mobile address (COA) to a communication status information server; A mobile station for updating the location information of the mobile node MN using the mobile address COA received from the mobile node MN and notifying the counterpart node CN by the presence information server. Notification step; And A first binding update step of performing, by the counterpart node CN, a binding update by obtaining current location information of the mobile node MN from the communication state information server; Soft handover method using communication status information in a wireless Internet system comprising a. The method of claim 1, A second binding update step in which a home agent HA receives a binding update signal from the mobile node MN, performs binding update accordingly, and returns a binding response; Soft handover method using the communication status information in the wireless Internet system further comprising. The method according to claim 1 or 2, The movement notification step, Internet Protocol (IP) based on the MAC access address of the mobile node MN using the mobile address COA received from the mobile node MN by the presence information server. Storing an address and a care-of address (COA) so as to correspond to each other; And Notifying, by the presence information server, of the location information update of the mobile node MN to the counterpart node CN; Soft handover method using communication status information in a wireless Internet system comprising a. The method according to claim 1 or 2, The first binding update step, As the counterpart node CN is notified of the location information update of the mobile node MN from the communication status information server, a query for requesting the location information of the mobile node MN is sent to the communication status information server. Transmitting; The communication state information server returning a response including the location information of the mobile node (MN) to the counterpart node (CN) according to the query; And Obtaining, by the counterpart node CN, current location information of the mobile node MN according to a response from the communication state information server, and performing binding update; Soft handover method using communication status information in a wireless Internet system comprising a. In a wireless Internet system with a processor, A mobile address assignment function in which the mobile node MN detects its own subnet movement and is assigned a mobile address COA from an external agent FA; A movement notification function of the mobile node (MN) informing its movement by transmitting the assigned movement address (COA) to a communication status information server; A mobile station for updating the location information of the mobile node MN using the mobile address COA received from the mobile node MN and notifying the counterpart node CN by the presence information server. Notification function; And A binding update function in which the counterpart node CN obtains current location information of the mobile node MN from the communication state information server and performs binding update; A computer-readable recording medium having recorded thereon a program for realizing this. The method of claim 5, A second binding update function in which a home agent HA receives a binding update signal from the mobile node MN, performs binding update accordingly, and returns a binding response; A computer-readable recording medium that records a program for further realization.