KR20170036956A - A Route Selection Scheme for WLAN Offloading Based on QoS Meseurement in EPC Network - Google Patents

Abstract

Provided is a method for selecting a WLAN offloading route according to QoS in an EPC network. The method includes the processes of: obtaining QoS information and selecting the route; performing the handover of UE to a WLAN network; and terminating a session with an E-UTRAN network. The process of performing the handover includes a WLAN offloading process and a handover process in an existing EPC network. Accordingly, the present invention can determine a proper handover traffic route through the measurement of QoS.

Description

[0001] The present invention relates to a method for selecting a WLAN offloading path according to QoS in an EPC network,

The present invention relates to a method for selecting a WLAN offload path according to QoS in an EPC network, and more particularly, to a method for selecting a WLAN offload path according to QoS, in order to solve a service quality guarantee problem caused by network overload occurring in WLAN offloading for an application service in an EPC network The present invention relates to a method of selecting a traffic route through a network.

Even if the 4G LTE and WLAN access networks continue to evolve, there is still a problem of service quality degradation due to service continuity and network conditions. 3GPP proposes MAPCON (Multi Access PDN Connectivity) and IFOM (IP Flow Mobility) as WLAN interworking technology to solve the overload problem of EPC (Evolved Packet Core) network. However, Quality is not guaranteed. In order to support network mobility and quality for application services in EPC environment, a method is needed

Accordingly, it is an object of the present invention to provide a WLAN offloading path selection method according to QoS in an EPC network that extends the functions of an existing IPv6 Header Option Routing Header and ICMPv6 (Internet Control Message Protocol version 6) message.

According to an aspect of the present invention, there is provided a method for selecting a WLAN offload path according to QoS in an EPC network, the method comprising: obtaining QoS information and selecting a path; performing a handover to a WLAN network by a UE; And terminating the session with the UTRAN network, wherein the handover process includes a process of WLAN offloading and a process of performing a handover in an existing EPC network.

According to the present invention, the modified WAG can check the network status through the QoS measurement in advance of the handover and determine a suitable handover traffic path through the measured information. And can be applied to provision of mobile application services that are becoming increasingly sophisticated.

1 is an overall system configuration diagram for explaining a traffic path selection technique according to an embodiment of the present invention.
FIG. 2 is a message flow diagram using a modified WAG according to an embodiment of the present invention. FIG. 2 is a diagram illustrating a process of selecting a path from a point in time when a UE is handed over to a WLAN network while a service is provided in an existing E-UTRAN network .
3 is a diagram illustrating an IPv6 option header extension according to an embodiment of the present invention.
4 is a flowchart illustrating a traffic path selection procedure for a modified WAG according to an exemplary embodiment of the present invention.

Hereinafter, an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

1 is an overall system configuration diagram for explaining a traffic path selection technique according to an embodiment of the present invention.

Referring to FIG. 1, a traffic path selection method according to an embodiment of the present invention is based on a result of collecting QoS information.

In the network environment of FIG. 1, the core network is the same as the existing EPC network. For the traffic path selection technique according to an embodiment of the present invention, a function is added to the WAG connecting the WLAN access network and the EPC network.

In the existing WAG, the UE only serves as a gate for the traffic transmitted through the WLAN access network. However, the modified WAG supports the WLAN offloading, and at the same time, the function of setting the path for the traffic using the QoS parameter information is added.

Even if the traffic route is designated through the WLAN offloading method, traffic overload may occur according to the network conditions, and the network service of lower quality than that of the previous E-UTRAN network may be provided. Therefore, in the proposed traffic path selection scheme, the WAG selects the path through the QoS information measured in the network when the UE performs the handover. When the WAG receives this information in advance, it is possible to predict the state of the network to which traffic is transmitted, so that it is possible to connect to the network in a smoother state.

FIG. 2 is a message flow diagram using a modified WAG according to an embodiment of the present invention. FIG. 2 is a diagram illustrating a process of selecting a path from a point in time when a UE is handed over to a WLAN network while a service is provided in an existing E-UTRAN network .

Referring to FIG. 2, the process of selecting a path from a point of time of handover to a WLAN network according to an embodiment of the present invention can be roughly divided into three processes. First, the first QoS information is obtained and a path is selected QoS information Query), a process of a second UE to hand over to a WLAN network, and finally, a process of terminating a session with an E-UTRAN network (Handover Completion). Here, the second handover process can be divided into two methods in detail. The WLAN offloading process (WLAN offloading handover) and the handover process in the existing EPC network (Basic Handover) are performed.

First, the process of requesting QoS information is performed in steps (1) to (7). In the initial state, an access bearer and a tunnel are generated up to the LTE interface of the UE and the P-GW.

A radio access bearer is created between the LTE interface and the eNB, and a PMIPv6 tunnel is generated between the eNB and the S-GW and between the GTP tunnel and the S-GW and the P-GW.

When a handover request is generated from the UE while the user is receiving the real-time service through the LTE network, the LTE interface is authenticated with the ePDG, the 3GPP AAA server, and the HSS after accessing the WAG.

Modified WAG is a process to acquire QoS information through both paths through ICMPv6 Message setup, and the collected information is stored in a cache entry.

In the cache entry, the QoS level for both paths is analyzed to determine the IP flow, and information about the flow determined by the HSS server and the UE is transmitted.

≪ 2-1 > in Fig. 2 is a handover process for WLAN offloading. When the HSS receives the notification about the IP flow determined by the HSS, the modified WAG requests the session connection.

The modified WAG sends the PBU message to the LMA (Local Mobility Anchor) of the PDN to which it belongs, registers the 3GPP AAA and LMA, and then transmits the PBA message to the modified WAG.

A radio access bearer between the WLAN interface and the modified WAG is created, a PMIPv6 tunnel is created between the modified WAG and the LMA of the PDN, and the IP connection between the UE and the CN is completed.

≪ 2-2 > in FIG. 2 is a handover procedure defined in the existing 3GPP TS 23.402. If it is determined that the service provision to the existing network is smooth rather than the WLAN offloading method using the previous QoS information in the modified WAG, the handover procedure is performed through this process, and the handover method is performed in the step [ 5) to (11).

Finally, when the handover procedure is completed in the <2-1> or <2-2> manner and the IP connection between the UE and the CN is established, a termination procedure for the existing LTE network session is performed.

The GTP tunnel between the LTE and the eNB, the GTP tunnel between the eNB and the S-GW, and the PMIPv6 tunnel between the S-GW and the P-GW are sequentially terminated, and the P-GW transmits a handover procedure completion message to the HSS in the P- .

The IP flow decision is performed in step (6) of FIG. Pre-QoS information of the user's application service is required prior to selecting the traffic route in the Modified WAG. In order to measure the QoS, the IPv6 header is extended and defined as shown in FIG.

The structure of the header according to an embodiment of the present invention is composed of a basic IPv6 header and an extension header, namely, a routing header and an ICMPv6 header.

The QoS measurement is performed on the network between the modified WAG and the CN and is divided into the measurement via the P-GW and the measurement via the Internet network without going through the EPC network.

The handover process in the modified WAG when the handover event occurs from the UE is shown in FIG.

modified When a handover event occurs in the WAG, it sets a timer for the corresponding traffic packet and stores it in the timer field of the cache entry.

In order to measure the QoS, two IPv6 Option Headers corresponding to the path passing through the P-GW and the WLAN offloading path are generated and transmitted to the CN.

Echo reply message, and stores the measured QoS information in an end-to-end delay field. QoS of each path is compared to set up the traffic path toward the smooth network state, notifying the HSS server and the UE, and completing the handover procedure.

When the QoS measurement of one side is delayed due to the network status, the traffic is transmitted to the path where the measurement is completed first, and the QoS measurement for the remaining path is continued until the previously set timer time is completed.

When the QoS measurement of the other path is completed, the QoS performance of the two paths stored in the cache entry is again compared and the path is reset. If QoS measurement is not performed until the timer time is completed, traffic is set up with the previously performed handover path and the handover procedure is completed.

Claims (2)

A method for selecting a WLAN offload path according to QoS in an EPC network for solving a service quality problem caused by network overload occurring when WLAN offload is applied to an application service in an EPC network,
The process of obtaining QoS information and selecting a path,
A process of the UE handing over to the WLAN network, and
And terminating the session with the E-UTRAN network,
Wherein the handover process comprises a WLAN offloading process and a handover process in an existing EPC network. The method as claimed in claim 1, wherein the WLAN off-
When receiving the notification of the IP flow determined by the HSS, the process of requesting the session connection with the modified WAG,
Transmitting a PBU message to a LMA (Local Mobility Anchor) of the PDN to which the modified WAG belongs, receiving the request, registering the 3GPP AAA and LMA, and transmitting the PBA message to the modified WAG, and
A radio access bearer between the WLAN interface and the modified WAG is created, a PMIPv6 tunnel is created between the modified WAG and the LMA of the PDN, and an IP connection between the UE and the CN is completed
And selecting a WLAN offload path according to the QoS in the EPC network.

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