KR20150101214A - method for obtaining IP addrss of mobile telecommunication terminal in LTE femtocell - Google Patents

Abstract

The present invention relates to a method for obtaining an IP address of a mobile telecommunication terminal in an LTE femto cell. The method for obtaining the IP address of the mobile telecommunication terminal in the LTE femto cell according to the embodiment of the present invention includes the steps of: storing a TEID after checking the TEID which is a bearer ID used in a data transmission between a femto base station and the mobile telecommunication terminal; determining whether the TEID of a GTP header is equal to a previously stored TEID; and determining a source IP address of uplink packet data as an IP address allocated in the corresponding mobile telecommunication terminal if the checked TEID is equal to the previously stored TEID.

Description

A method for obtaining an IP address of a mobile communication terminal in an LTE femtocell,

The present invention relates to a method for acquiring an IP address of a mobile communication terminal in an LTE femtocell, and more particularly, to an LTE femtocell acquiring an IP address of a mobile communication terminal from a signaling message and a data message of an S1 interface, And a method of acquiring an IP address of a communication terminal.

As is well known, a femto cell base station (hereinafter, simply referred to as a 'femto base station') is a very small mobile communication base station connected to a mobile communication core network through a broadband network installed in a house or an office. These femto base stations have various advantages such as expanding indoor coverage, improving call quality, and efficiently providing various wired / wireless convergence services.

In 3GPP LTE (Long Term Evolution), an evolved NodeB (eNB) and a home evolved NodeB (HeNB) have been defined. The eNB is a macro base station that manages a general macro cell and the home eNB is a femto base station that controls a femtocell. That is, 3GPP considers an environment in which a femto base station that can be connected to only a specific user is installed separately from an existing macro base station. At this time, the femto base station may be installed by a user or a provider for the purpose of increasing coverage, increasing capacity, or providing other differentiated services. The service coverage of a femto base station can be considered from a minimum of several meters to a maximum macro service coverage degree.

1 is a diagram illustrating a structure of a wireless communication network including a femto base station and a femto base station gateway. The wireless communication network according to FIG. 1 includes a mobile communication terminal (UE) 100, a local PDN gateway (L-PGW) 101 and a local serving gateway (L-SGW) A femto base station (HenB) 103, a macro base station (eNB) 108, a femto base station gateway (HeNB GW) 104, a mobile management entity (MME) A macro-serving gateway (S-GW) 106 in the core network, and a PDN gateway (P-GW) 107 in the core network.

In the above-described configuration, the macro base station 108 is a base station for managing macrocells, and is connected to the mobile communication terminal 100 via a wireless channel, and controls radio resources for the mobile communication terminal 100. [ For example, the macro base station 108 may generate necessary system control information in a macrocell and broadcast it, or may allocate radio resources to exchange data or control information with the mobile communication terminal 100.

In addition, the macro base station 108 may collect the channel measurement result information of the current cell and neighbor cells from the mobile communication terminal 100, determine the handover, and instruct the handover. The macro base station 108 for this purpose includes a control protocol such as a radio resource protocol related to radio resource management.

Next, the mobility management entity 105 manages a mobile communication terminal in an idle mode, and selects a PDN gateway and a serving gateway. In addition, the mobility management entity 106 performs functions related to roaming and authentication, and processes bearer signals generated in the mobile communication terminal 100. [

The serving gateway 106 serves as a mobility anchor when performing handover between base stations or between 3GPP wireless networks. The PDN gateway 107 allocates an IP address of the mobile communication terminal 100, performs a packet data related function of the core network, and acts as a mobile anchor when moving between a 3GPP wireless network and a non-3GPP wireless network. The PDN gateway 107 also determines the bearer band provided to the subscriber, and performs forwarding and routing functions on the packet data.

The femto base station 103 is connected to a core network such as the mobility management entity 105 via a radio network controller to provide mobile communication services to the mobile communication terminal 100. Here, the femtocell may also be referred to as a CSG cell (Closed Subscriber Group Cell), which refers to a cell that can only access terminals belonging to a specific group (i.e., CSG) registered in advance so as to be able to access the cell. Such a CSG cell may be a home cell or an enterprise / regional network cell installed in a narrow area, such as a private home, or a corporate / regional network cell installed in a large area for a specific organization.

The local serving gateway 102 is a serving gateway existing in the femto base station, and the local PDN gateway 107 is a PDN gateway existing in the femto base station. The femto base station gateway 104 performs a role of connecting the mobility management entity 105 and the femto base station 103. In this network, the mobile communication terminal 100 can access the core network through the macro base station 108 or the femto base station 103.

Meanwhile, in the LTE femtocell system, the IP address information allocated to the mobile communication terminal may be required.

However, in the LTE system, NAS (Non Access Stratum) messages including an IP address allocated to a mobile communication terminal are transmitted as encrypted control messages exchanged between a mobile communication terminal and an EPC (Evolved Packet Core) The IP address assigned to the mobile communication terminal can not be obtained.

10-2010-119349 (Title of the Invention: Method and apparatus for supporting local IP access in a wireless communication network including femtocells) * 10-2010-120259 (entitled " Control Plane Server < / RTI > in a Mobile Communication Network and Method of Controlling Connection Settings)

SUMMARY OF THE INVENTION The present invention has been conceived to solve the above-described problems, and it is an object of the present invention to provide a method and apparatus for receiving a signaling message and a data message of an S1 interface, which is a matching standard between an LTE femtocell and an EPC, And a method for acquiring an IP address of a mobile communication terminal in an LTE femtocell.

A method for acquiring an IP address of a mobile communication terminal in an LTE femtocell according to the present invention is performed by a femto base station and continuously analyzes a signaling message received through an S1 interface from a core network to generate a bearer ID to be used for data transmission between the femto base station and a mobile communication terminal (A) storing the TEID after confirming the TEID; (B) determining whether the TEID of the GTP header added to the uplink packet data received from the UE is equal to the TEID stored in the step (a) after checking the TEID of the GTP header added to the uplink packet data received from the UE, And determining (c) the source IP address of the uplink packet data as an IP address assigned to the mobile communication terminal when the stored TEID is identical.

In the above-described configuration, in the step (a), the TEID is extracted from an Initial context Setup Request message which is an S1 message.

In step (a), the extracted TEID is stored in a terminal IP address table, and the source IP address field of the address table is left blank. In step (c), if the TEID and the stored TEID are identical The source IP address of the uplink packet terminal is determined as the IP address assigned to the mobile communication terminal only when the source IP address field of the address table is empty.

According to the method of acquiring an IP address of a mobile communication terminal in an LTE femtocell of the present invention, an IP address of a mobile communication terminal can directly be obtained from a signaling message and a data message of an S1 interface without passing through an NAS PDU encrypted in the LTE femto base station . The obtained IP address of the mobile communication terminal can be utilized to reduce the load of the core network by directly transmitting IP traffic from the femtocell to the home network instead of the external network, that is, performing LIPA (Local IP Access).

1 illustrates a structure of a wireless communication network including a femto base station and a femto base station gateway.
2 is a sequence chart for explaining a process in which a mobile communication terminal accesses a femto base station and attaches to an EPC.
3 is a flowchart illustrating a process of acquiring and storing a TEID in an initial context setup request message transmitted from an EPC in a femto BS according to the present invention;
4 is a flowchart illustrating a process of extracting an IP address allocated to a mobile communication terminal in a data packet transmitted from a mobile communication terminal to an EPC in a femto BS according to the present invention.

Hereinafter, a method of acquiring an IP address of a mobile communication terminal in an LTE femtocell according to the present invention will be described in detail with reference to the accompanying drawings.

2 is a sequence chart for explaining a process of attaching the mobile communication terminal to the femto base station and attaching the mobile communication terminal to the femto base station. As shown in FIG. 2, in order to connect a mobile communication terminal (hereinafter referred to simply as a 'terminal') to a femto base station and attach it to an EPC, an RRC connection establishment procedure is first performed . If the RRC connection establishment is successful in this manner, the UE transmits an RRC Connection Setup Complete message to the femto base station, and the NAS 'Attach Request' message is included in the RRC message.

Next, the femto base station receives the RRC message from the UE and transmits an S1 control message including the NAS message (Attach Request) to the MME. Then, after the MME creates a session with the S-GW (Serving Gateway), the MME transmits an Initial Context Setup Request, which is an S1 control message including 'Attach Accept', as a response to the 'Attach Request' message to the femto base station. In this process, the femto base station receives an 'Attach Accept' message from the MME.

Next, the femto base station performs Initial Security Activation and receives capability information from the terminal through the RRC procedure. Next, the femto base station acquires the latest terminal capability from the terminal by performing the RRC connection reconfiguration procedure using the received terminal capability information.

Next, the femto base station transmits an Initial Context Setup Response, which is an S1 control message including the terminal capability information, to the MME. After the terminal generates a NAS-based connection completion message, a connection completion message or an Attach Complete message, the terminal encapsulates the generated message in the RRC-based direct transfer message and transmits it to the femto base station.

Next, the femto base station extracts the connection completion message, the connection completion message, or the attachment completion message from the Direct Transfer message, encapsulates the extracted message in an S1-AP based Uplink (NAS) Transport Message (UL) send.

Meanwhile, the MME transmits a bearer change request message, for example, a Modify Bearer Request message to the S-GW in the EPC in order to change the generated bearer, and the S-GW transmits a Modify Bearer Response message to the MME in response thereto Thus, UL / DL payload data can be transmitted and received between the terminal and the S-GW.

As described above, when the terminal enters the service area of the femto base station, it performs the process shown in FIG. 2 to receive an IP address to use from the EPC. In this process, the EPC establishes a bearer to be used for data transmission between the femto base station and the UE on the S1 interface. The ID of the bearer set in this way is called 'TEID'. This TEID is contained in the Initial Context Setup Request (Attach Accept) message, which is the S1 signaling message shown in FIG.

When the terminal transmits an IP packet to the EPC, the IP packet is first transmitted to the femto base station. Afterwards, the femto base station attaches a GTP (GPRS Tunneling Protocol) header to the IP packet and performs tunneling operation to communicate with the EPC. At this time, the TEID assigned by the EPC is attached to the GTP header.

Therefore, it is first detected through the Initial Context Setup Request message that a new bearer having the TEID is assigned to the UE, and if the TEID of the GTP header of the IP packet transmitted from the UE to the EPC is a new bearer, If the source IP address of the IP packet is extracted, the IP address of the terminal can be known.

FIG. 3 is a flowchart illustrating a process of acquiring and storing a TEID in an initial context setup request message transmitted from an EPC in a femto BS according to an embodiment of the present invention. And extracting an IP address allocated to the mobile communication terminal in the data packet.

First, as shown in FIG. 3, the femto base station continuously analyzes the signaling message received through the S1 interface from the EPC (step S10), and determines whether the received signaling message is an initial context setup request message (step S20). As a result of the determination in step S20, if the received signaling message is not the Initial context Setup Requests message, the process returns to step S10. If the received signaling message is correct, the process proceeds to step S30 to parse and confirm the TEID included therein (step S40) , And further performs step S40 to store the parsed TEID in the terminal IP address table. Leave the source IP address field blank in the address table.

Next, as shown in FIG. 4, when the uplink (UL) packet data is received from the terminal (step S100), the femto base station checks the TEID of the GTP header added to the packet, It is judged whether or not it is equal to the TEID stored in the address table (step S110).

If it is determined in step S110 that the confirmed TEID is equal to the TEID stored in the terminal IP address table, the process proceeds to step S120 to determine whether there is an IP address matched thereto.

If it is determined in step S110 that the confirmed TEID is not the same as the TEID stored in the terminal IP address table or if there is an IP address matching the corresponding TEID in step S120, The process returns to step S100.

On the other hand, if it is determined in step S110 that the confirmed TEID is equal to the TEID stored in the terminal IP address table and that there is no IP address matched with the corresponding TEID in step S120, the corresponding IP address is allocated to the terminal The source IP address of the uplink data packet obtained by parsing the source IP (step S130) is stored in the terminal IP address table (step S140).

Although the preferred embodiments of the method of acquiring an IP address of a mobile communication terminal in the LTE femtocell according to the present invention have been described in detail with reference to the accompanying drawings, it is to be understood that the invention is not limited to the above- Will be possible. Accordingly, the scope of the present invention should be determined by the following claims.

100: mobile communication terminal, 101: local serving gateway (L-SGW)
102: local PDN gateway (L-PGW), 103: femto base station,
104: femto base station gateway, 105: mobility management entity (MME),
106: Serving gateway (S-GW), 107: PDN gateway (P-GW)
108: macro base station

Claims (3)

Performed by a femto base station,
(A) continuously analyzing a signaling message received through the S1 interface from the core network to confirm and storing the TEID which is a bearer ID to be used for data transmission between the femto base station and the mobile communication terminal;
(B) determining whether the TEID of the GTP header added to the uplink packet data received from the UE is equal to the TEID stored in the step (a), and
(C) determining a source IP address of the uplink packet data as an IP address assigned to the mobile communication terminal when the determined TEID is equal to the stored TEID as a result of the determining in the step (b) The method comprising the steps of: acquiring an IP address of a mobile communication terminal in an LTE femtocell; The method according to claim 1,
Wherein the TEID is extracted from an initial context setup request message which is an S1 message in step (a). 3. The method of claim 2,
In the step (a), the extracted TEID is stored in a terminal IP address table, the source IP address field of the address table is left blank,
In the step (c), when the confirmed TEID is equal to the stored TEID, only when the source IP address field of the address table is blank, the source IP address of the uplink packet terminal is set to the IP address The method comprising the steps of: (a) receiving an IP address of a mobile communication terminal in an LTE femtocell;

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