KR101128527B1 - Method for minimizing packet losses in handover with different mobile networks - Google Patents

Abstract

The present invention relates to a method for minimizing packet loss during handover between heterogeneous networks. The present invention relates to a method for minimizing packet loss during a handover procedure through a home agent entity that manages IP mobility during handover between heterogeneous networks. By buffering and forwarding the handover to the mobile terminal, packet loss during handover between heterogeneous networks can be minimized.

Heterogeneous Network, Handover, Handover Notification Message, Home Agent Object, Data Forwarding

Description

Method for minimizing packet losses in handover with different mobile networks}

The present invention relates to a method for minimizing packet loss during handover between heterogeneous networks, and more particularly, to a handover technique between heterogeneous networks having different network environments.

The present invention is derived from the research conducted as part of the IT growth engine core technology development project of the Ministry of Knowledge Economy and the Ministry of Information and Telecommunications Research and Development. ].

The problem with handover between heterogeneous networks where UE (User Equipment) initiates handover is that packet loss to the mobile terminal may occur until the mobile terminal accesses the new network and completes the handover. Is the point.

1 and 2 are flowcharts illustrating a handover procedure between a conventional 3GPP network and a non-3GPP network. FIG. 1 is a flowchart illustrating a handover procedure from a conventional non-3GPP network to a 3GPP network. Is a flowchart illustrating a handover procedure from a 3GPP network to a non-3GPP network.

When the mobile terminal 10 accesses the first network 20 (S110) to receive a service, and determines the handover to the second network 30 (S120), when the handover procedure is started, the mobile terminal receives a second service. Attempts to access the network (S130), the path is changed by the second network (S140) and the handover procedure is completed.

Then, the IP connection between the mobile terminal and the second network (S150), the second network requests the resource release to the first network, the first network relays the resource release request to the mobile terminal between the mobile terminal and the first network The allocated resource is released (S160).

In the case of FIG. 1, the first network is a non-3GPP network, and the second network is a 3GPP network. In contrast, in FIG. 2, the first network is a 3GPP network and the second network is a non-3GPP network. 1 and 2 illustrate a 3GPP LTE system configuration as a 3GPP network.

However, in the conventional handover process, all packets transmitted to the mobile station as a destination are transmitted to the previous network (the first network) until the handover procedure is started and the handover procedure is completed. Since the wireless environment of the first network is degraded or disconnected and connected to a new network (second network), if a packet is continuously transmitted to the previous network that is bad or disconnected during the handover procedure, the packet is eventually lost. It was likely to cause.

Accordingly, the present inventors have studied a technique for minimizing packet loss during handover between heterogeneous networks having different network environments.

The present invention has been invented under the above-described purpose, and an object thereof is to provide a method capable of minimizing packet loss during handover between heterogeneous networks having different network environments.

According to an aspect of the present invention for achieving the above object, in the method for minimizing packet loss during handover between heterogeneous networks according to the present invention, a mobile terminal which determines a handover from a first network currently connected to a second network is a mobile terminal. When a Handover Indication message is transmitted to a Home Agent object that manages IP mobility of the home agent, the Home Agent object receiving the buffer is buffering data transmitted to the corresponding mobile terminal. When the mobile terminal accesses the second network and the handover procedure is completed, the mobile terminal forwards the buffered data.

According to an additional aspect of the present invention, in the packet loss minimization method in the handover between heterogeneous networks according to the present invention, the home agent entity receives and stores the remaining packet data not transmitted in the handover process from the first network. When the mobile terminal accesses the second network and the handover procedure is completed, the mobile terminal forwards the untransmitted residual packet data.

The present invention buffers data transmitted to a mobile station while performing a handover procedure through a Home Agent entity managing IP mobility during handover between heterogeneous networks, and forwards it to the mobile terminal after handover. It has a useful effect of minimizing packet loss during handover.

The present invention receives and stores the remaining packet data not transmitted in the handover process from the first network through a Home Agent entity that manages IP mobility during heterogeneous network handover. When the handover procedure is completed by accessing the network, the buffered data can be forwarded to minimize packet loss during the handover between heterogeneous networks.

In addition, data is buffered through the Home Agent object, which manages IP mobility, minimizing the impact on the handover procedure, and data recovery is easy because packet loss does not occur even when a new network connection fails. Simple.

In addition, there is no need for a separate tunnel for packet forwarding, and the packet buffering and forwarding procedures are performed independently of the handover, and thus do not affect the handover itself.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily understand and reproduce the present invention.

In the following description of the present invention, detailed descriptions of well-known functions or configurations will be omitted if it is determined that the detailed description of the embodiments of the present invention may unnecessarily obscure the gist of the present invention.

Prior to describing the present invention, terms used throughout the specification are defined. These terms are terms defined in consideration of functions in the embodiments of the present invention, and are terms that can be sufficiently modified according to the intention, convention, etc. of the user or operator, and the definitions of these terms are based on the contents throughout the specification of the present invention. Will have to be lowered.

Handover between heterogeneous networks means handover between two wireless networks having different network environments.

Handover Indication (Handover Indication) message is a home agent (HA: Home Agent) that manages the IP mobility of the mobile terminal by the mobile terminal that has decided to handover from the currently connected first network (old network) to the second network (new network). The home agent (HA) buffers data transmitted to the mobile station from the time when the message is received until the mobile station accesses the second network (new network).

3 and 4, a procedure for minimizing packet loss in a method for minimizing packet loss during handover between heterogeneous networks according to the present invention will be described. 3 is a flow chart according to an embodiment of a method for minimizing packet loss during handover between heterogeneous networks according to the present invention, and FIG. 4 is a flow chart according to another embodiment of a method for minimizing packet loss during handover between heterogeneous networks according to the present invention. to be.

3 is a diagram illustrating an example of a packet loss minimization procedure when a mobile terminal performs a handover from a non-3GPP network to a 3GPP network, and FIG. Illustrates an example of a packet loss minimization procedure in FIG.

In the case of FIG. 3, the old network (first network) is a non-3GPP network, the new network (second network) is a 3GPP network, and in FIG. 4, the old network (first network) is a 3GPP network, and a new network (second network). Network) is a non-3GPP network.

3 and 4 illustrate a 3GPP LTE system configuration as a 3GPP network. The 3GPP LTE system is an evolution of UTRA and UTRAN of a packet-based UMTS system, which is an asynchronous mobile communication system, and has a low round trip time of 10 ms or less, 100 Mbps of downlink, and 50 Mbps of uplink. Instead of using the existing circuit switched network, which guarantees high data transmission rate and low efficiency of network resources, the packet switched network is used to easily connect the PDN and the user terminal. As a technology, standardization of wireless access technology is in progress.

In particular, the network constituting the 3GPP LTE system is a structure in which an Evolved Packet Core (EPC) network, which is an evolved core network connecting an external network and a wireless access network, and an Evolved Universal Terrestrial Radio Access Network (EUTRAN) network, which is an evolved wireless access network, are matched. The UE (User Equipment), which is a terminal, is connected to the 3GPP LTE system through the nodes constituting these networks to provide a high-speed data transmission and a communication service capable of IP-based services. Here, the matching between the EPC and the EUTRAN is made through the S1 interface, and the matching between the eNBs in the EUTRAN is made of a mesh structure through the X2 interface.

The network elements that make up the EPC network are the System Architecture Evolution Access Gateway and the UE, which are in charge of access services between IP-based wired and wireless access networks, routing and forwarding packets, and gateway functions for connecting to external PDNs. Mobility Management Entity (MME) that performs mobility management and authentication, management of bearers, sessions, and non-access stratum (NAS) signaling control.

The access gateway performs IP-based access function and packet routing and forwarding of the wireless access network and the wired network through matching between the PDN gateway, which is in charge of the gateway function for connecting to an external PDN, and the 3GPP LTE system. It is composed of a serving gateway.

The network element constituting the EUTRAN network provides a radio access interface for radio transmission and reception between UEs in one or more cells, and manages and controls radio resources, and transmits and processes data through radio transmission and reception between UEs. It consists of an evolved Node B (eNB). The eNB performs a radio access function integrating the original role of RNC and Node B in UTRAN, which is a radio access network of the existing third generation UMTS.

As shown in the figure, when the mobile terminal 10 determines the handover to the second network 30 due to a bad or disconnected wireless environment of the first network 20 to which the mobile terminal 10 is currently connected, the mobile terminal notifies the handover step. In S210, a Handover Indication message is transmitted to a Home Agent (HA) entity 40 managing IP mobility of the mobile station.

Then, the home agent entity that receives the handover notification message from the mobile station buffers the data transmitted to the mobile station in the data buffering step (S220).

In this case, the home agent entity may be included in either the first network or the second network. For example, the home agent entity may be a packet data network (PDN) gateway of a 3GPP network.

The PDN gateway is responsible for a gateway function for connecting to an external PDN and includes a home agent (HA) function for managing IP mobility of a mobile terminal.

Then, when the mobile terminal accesses the second network and completes the handover procedure, the home agent entity forwards the data buffered to the mobile terminal in the data forwarding step (S230).

For example, in the data forwarding step (S230), the home agent entity may determine whether the handover procedure is completed by checking the IP connectivity between the mobile terminal and the second network.

If it is determined that the handover procedure is completed, the home agent entity forwards the data buffered by the buffering step S220 to the corresponding mobile terminal through the data forwarding step S230.

Accordingly, in this way, the packet loss minimization method for handover between heterogeneous networks according to the present invention is transmitted to a mobile terminal while performing a handover procedure through a Home Agent entity that manages IP mobility during handover between heterogeneous networks. By buffering the data, and forwarding it to the mobile terminal after handover, it is possible to minimize packet loss during handover between heterogeneous networks.

In addition, data is buffered through the Home Agent object, which manages IP mobility, minimizing the impact on the handover procedure, and data recovery is easy because packet loss does not occur even when a new network connection fails. Simple.

In addition, there is no need for a separate tunnel for packet forwarding, and the packet buffering and forwarding procedures are performed independently of the handover, and thus do not affect the handover itself.

On the other hand, according to an additional aspect of the present invention, the packet loss minimization method in the handover between heterogeneous networks according to the present invention may further include a residual packet receiving step (S225). In the remaining packet receiving step (S225), a Home Agent (HA) entity receiving a Handover Indication message from the mobile station requests to transmit the remaining packet data not transmitted in the handover process to the first network. Receive residual packet data from this.

When the mobile terminal accesses the second network and completes the handover procedure, the home agent (HA) entity receives the residual packet data received by the residual packet receiving step (S225) through the data forwarding step (S230). Forward more.

In this case, the residual packet data may be transmitted from the first network to the home agent entity through a PMIP (Proxy Mobile IP) tunnel generated between the first network and the home agent entity in the step of receiving the residual packet (S225).

In the PMIP regulations, mobility signaling, two-way tunnel for packet forwarding, security association (SA) creation and registration procedure between PMMA (PMMA) and home agent (HA), IP interface configuration of the mobile terminal, and Dynamic home discovery is defined.

During the handover process, a two-way tunnel for packet delivery defined in this PMIP rule is created between the first network and the home agent entity, and the remaining packet data is transmitted from the first network to the home agent entity. Unprocessed remaining packet data can be processed.

Meanwhile, the entity for transmitting the residual packet data to the home agent entity may be a serving gateway of a 3GPP network or an evolved packet data gateway (ePDG) of a non-3GPP network.

The Serving Gateway and evolved Packet Data Gateway (ePDG) perform IP-based access functions and routing and forwarding of packets on wireless and wired networks, so when handing over from a mobile terminal 3GPP network to a non-3GPP network, they belong to the 3GPP network. The remaining packet data is transmitted from the serving gateway to the home agent entity, and when the mobile terminal handovers from the non-3GPP network to the 3GPP network, the home agent (evolved packet data gateway) from the ePDG (evolved packet data gateway) belonging to the non-3GPP network Home Agent) can be implemented to send the remaining packet data to the object.

That is, the present embodiment receives and stores the remaining packet data not transmitted in the handover process from the first network through a Home Agent entity managing IP mobility during heterogeneous network handover. When the handover procedure is completed by accessing the second network, the packet loss during handover between heterogeneous networks can be minimized by forwarding untransmitted residual packet data.

As described above, the packet loss minimization method in the handover between heterogeneous networks according to the present invention is performed by a mobile terminal during a handover procedure through a Home Agent entity managing IP mobility in the handover between heterogeneous networks. By buffering the transmitted data and forwarding it to the mobile terminal after handover, packet loss during handover between heterogeneous networks can be minimized.

In addition, through the Home Agent entity that manages IP mobility during handover between heterogeneous networks, residual packet data not transmitted in the handover process is received and stored from the first network, and the corresponding mobile terminal is transferred to the second network. When the handover procedure is completed by accessing the data, the buffered data can be forwarded to minimize packet loss in the handover between heterogeneous networks.

In addition, data is buffered through the Home Agent object, which manages IP mobility, minimizing the impact on the handover procedure, and data recovery is easy because packet loss does not occur even when a new network connection fails. It is simple and does not require a separate tunnel formation for packet forwarding, and since the packet buffering and forwarding procedures are performed independently of the handover, the object of the present invention described above can be achieved without affecting the handover itself. have.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims. .

The present invention can be used industrially in the field of handover technology of the mobile terminal or its application technology.

1 is a flowchart illustrating a handover procedure from a conventional non-3GPP network to a 3GPP network.

2 is a flowchart illustrating a handover procedure from a conventional 3GPP network to a non-3GPP network.

3 is a flowchart according to an embodiment of a packet loss minimization method in a handover between heterogeneous networks according to the present invention.

4 is a flowchart according to another embodiment of a method for minimizing packet loss during heterogeneous network handover according to the present invention.

<Explanation of symbols for the main parts of the drawings>

10: mobile terminal 20: first network

30: second network 40: home agent object

Claims (9)

delete delete A handover notification step of transmitting a handover notification message to a home agent entity that manages IP mobility of the mobile terminal, which has determined handover from the first network to the second network; ; A data buffering step of the home agent entity receiving the handover notification message from the mobile terminal buffering data transmitted to the mobile terminal; The home agent entity receiving the handover notification message from the mobile station requests the first network to send the remaining packet data that has already been received to the first network before handover but has not been transmitted to the mobile station due to the handover. Residual packet receiving step of receiving; When the mobile terminal connects to the second network and the handover procedure is completed, the home agent entity transfers the data buffered by the data buffering step and the residual packet data received by the residual packet receiving step to the mobile terminal. A data forwarding step of forwarding; Packet loss minimization method in the handover between heterogeneous networks comprising a. The method of claim 3, wherein In the remaining packet receiving step: Residual packet data is transmitted from the first network to the home agent entity through the PMIP (PMIP) tunnel, packet loss minimization method in heterogeneous network handover. The method of claim 3, wherein In the data forwarding step: A method for minimizing packet loss during handover between heterogeneous networks, wherein the home agent entity determines whether the handover procedure is completed by checking the IP connectivity between the mobile station and the second network. The method according to claim 3 or 4, The home agent (Home Agent) entity is included in any one of the first network or the second network, packet loss minimization method during inter-network handover, characterized in that. The method of claim 6, The home agent (Home Agent) is a packet data network (PDN) gateway of the 3GPP network, packet loss minimization method during heterogeneous network handover, characterized in that. The method of claim 7, wherein The method for minimizing packet loss during handover between heterogeneous networks, wherein the entity for transmitting residual packet data to the home agent entity is a serving gateway of a 3GPP network. The method of claim 7, wherein The method for minimizing packet loss during handover between heterogeneous networks, wherein the entity for transmitting residual packet data to the home agent entity is an evolved packet data gateway (ePDG) in a non-3GPP network.

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