WO2015020270A1

WO2015020270A1 - Mobile communication system and method supporting circuit-switched fallback

Info

Publication number: WO2015020270A1
Application number: PCT/KR2013/009883
Authority: WO
Inventors: 우주인; 이화근; 김재현; 김진봉; 김현직; 박경렬; 구재형; 박병창
Original assignee: 주식회사 케이티
Priority date: 2013-08-06
Filing date: 2013-11-04
Publication date: 2015-02-12
Also published as: AP2016009040A0; KR102129901B1; KR20150017264A

Abstract

A mobile communication system, which includes a long term evolution (LTE) network, connected to a plurality of circuit switched (CS) domain provider networks, for providing a circuit switched fallback (CSFB), comprises: an eNodeB for receiving a connection request from a terminal; and a mobility management entity (MME) for storing a table in which provider identification information, a tracking area (TA) and a location area (LA) on the terminal are matched, receiving the connection request from the eNodeB and sending, with reference to the table, a request for a location update for the terminal to an MSC which covers the LA corresponding to the provider identification information of the provider to which the terminal subscribes and the TA where the terminal is currently located

Description

Mobile communication system and method that supports circuit switched fallback

The present invention relates to circuit switched fallback (CSFB), and more particularly, to a system and method for supporting circuit switched fallback in an LTE network connected to each circuit network operated by a plurality of operators.

In general, voice service of LTE (Long Term Evolution) network that provides data service uses self-circuit network to perform circuit switched fallback within a single operator. 3GPP standard considers only CSFB to a circuit network operated by a single operator. have. In the case where multiple operators use one LTE network, the base station and the MME may not know which circuit network the CSFB should be performed even if the CSFB is to be operated by the circuit network operated by each operator.

An object of the present invention is to provide a mobile communication system for providing a CSFB in a situation where a plurality of CS domain operator networks and a single LTE network are connected.

According to an aspect of the present invention, in a mobile communication system including a Long Term Evolution (LTE) network connected to a plurality of CS (Circuit Switched) domain operator network to provide a Circuit Switched FallBack (CSFB), the connection request from the terminal ENodeB for receiving; And a table in which operator identification information, a tracking area (TA), and a location area (LA) of the terminal are matched, receive the connection request from the eNodeB, refer to the table, and the operator of the operator to which the terminal is subscribed. A mobile communication system including an MME for requesting a location update for the terminal is provided to the MSC in charge of the identification information and the LA corresponding to the TA where the terminal is currently located.

When the MME receives a paging request from the MSC according to an outgoing call request of another terminal, the MME transmits a paging request to the eNodeB, and the eNodeB includes frequency information of a NodeB corresponding to the MSC according to the paging request. By sending an access message to the terminal, the terminal may be handed over from the eNodeB to the NodeB.

When the MME receives the message requesting the CSFB from the terminal after transmitting the paging request to the eNodeB, the MME transmits to the eNodeB the SPID inserting the operator identification flag in a predetermined unused bit, the eNodeB An access message including frequency information corresponding to the operator identification flag included in the SPID may be transmitted to the terminal.

The MME may perform an authentication process according to the connection request and extract the SPID from a message received from a home subscriber server (HSS) during the authentication process.

According to another aspect of the present invention, a method for supporting a CSFB in a mobile communication system including a Long Term Evolution (LTE) network connected to a plurality of CS (Circuit Switched) domain operator network to provide a Circuit Switched FallBack (CSFB) The method comprising: receiving, by an eNodeB, a connection request from a terminal and transmitting the connection request to a mobility management entity (MME); Generating, by the MME, a table in which operator identification information, a tracking area (TA), and a location area (LA) of the terminal are matched; And requesting, by the MME, a location update request for the terminal to an MSC in charge of LA corresponding to the operator identification information of the operator to which the terminal is subscribed to and the TA where the terminal is currently referred to by referring to the table. Support methods are provided.

The CSFB supporting method may further include: receiving, by the MME, a paging request from the MSC according to an outgoing call request of another terminal; Sending, by the MME, a paging request to the eNodeB; And allowing the terminal to handover from the eNodeB to the NodeB by transmitting an access message including the frequency information of the NodeB corresponding to the MSC to the terminal according to the paging request.

After the MME transmits a paging request to the eNodeB, when the MME receives a message requesting a CSFB from the UE, transmitting a SPID in which the operator identification flag is inserted into a predetermined unused bit to the eNodeB. The method may further include, wherein the eNodeB transmits an access message including frequency information of a NodeB corresponding to the MSC to the terminal according to the paging request, so that the terminal is handed over from the eNodeB to the NodeB. The eNodeB may be a step of transmitting an access message including frequency information corresponding to the service provider identification flag included in the SPID to the terminal.

In the CSFB supporting method, after the eNodeB receives a connection request from a terminal and transmits the connection request to an MME, the MME performs an authentication process according to the connection request, and a message received from a home SSUBSCRIBER server (HSS) during the authentication process. The method may further include extracting the SPID from the.

As described above, according to the present invention, a circuit switched fallback may be provided for each circuit network operated by a plurality of operators connected to a single LTE network.

1 is a block diagram illustrating a mobile communication system in accordance with an embodiment of the present invention.

2 is a flowchart illustrating an attach process for providing circuit switched fallback in a mobile communication system according to an embodiment of the present invention.

3 is a call processing flowchart illustrating a process before a terminal is handed over when a calling terminal transmits a terminal to an idle terminal in a mobile communication system according to an embodiment of the present invention.

The present invention may be variously modified and have various embodiments, and specific embodiments will be illustrated in the drawings and described in detail with reference to the accompanying drawings. However, this is not intended to limit the present invention to specific embodiments, it should be understood to include all modifications, equivalents, and substitutes included in the spirit and scope of the present invention.

Also, in the present specification, when one component is referred to as "transmitting a signal" to another component, the one component may be directly connected to the other component to transmit a signal, but there is a specially opposite description. It is to be understood that unless otherwise, the signal may be transmitted in the intermediary with another component.

1 is a block diagram illustrating a mobile communication system according to an embodiment of the present invention.

Referring to FIG. 1, a user equipment (UE) 100 accesses a Long Term Evolution (LTE) network 200 when using a data service, and receives a CS service (eg, a voice service as well as an image). When using the service, Short Message Service (SMS), LoCation Services (LCS), and Unstructured Supplementary Service Data (USSD), the first carrier network 110 and the UMTS Terrestrial Radio Access Network (UTRAN) CS (Circuit Switched) network 2 is connected to the operator network 120. As such, the mobile communication system includes an LTE network 130, which is not capable of circuit-switched communication, and a UTRAN network, such as WCDMA / GSM, capable of circuit-switched communication.

Here, the terminal 100 is a terminal that supports Circuit Switched Fallback (CSFB).

The CSFB is the first operator network 110 when a mobile originate (MO) call or an MT (Mobile Terminate) call is generated while the terminal 100 serving in the LTE cell area is in the LTE cell. Alternatively, the mobile terminal 100 provides a CS service by handing over the terminal 100 to the second provider network 120.

The LTE network 130 is a network that supports only a packet switch (PS) scheme and is connected to the first operator network 110 and the second operator network 120 to the terminal 100 joined to each operator network. Provide mobile communication services.

LTE network 130 includes an eNodeB 132, a Mobility Management Entity (MME) 134, and a Home Subscriber Server (HSS) 136.

The eNodeB 132 is a base station apparatus of a wireless access network of LTE, and provides a paging request for CSFB and a direct connection function to a target cell capable of CS service.

The HSS 136 stores subscriber information including a Subscriber Profile ID (SPID). In addition, the HSS 136 may perform an authentication process in response to receiving the subscriber authentication request message in association with the MME 134, and may transmit an authentication information response message including the SPID to the MME 134.

The MME 134 stores a mapping table in which a tracking area (TA) and a location area (LA) are mapped. In this case, the general mapping table as shown in Table 1 maps only the TA and the LA, and the conventional MME determines the LA corresponding to the specific TA by referring to the mapping table and connects the terminal 100 to the CS network corresponding to the corresponding LA. The CSFB may be performed as much as possible.

Table 1

TA	LA
TA1	LA1
TA1	LA2

However, when a plurality of

carrier networks

110 and 120 are connected to the LTE network 130, there may be a plurality of LAs mapped to a specific TA, and which CSFB should be made through the MSC corresponding to one of the plurality of LAs. Cannot be determined by a conventional MME.

The MME 134 according to an embodiment of the present invention stores a mapping table mapping operator network identification information and TA and LA. That is, the MME 134 may store a mapping table according to Table 2 below.

TABLE 2

Operator Network Identification Information	TA	LA
First business identity flag	TA1	LA1
Second business operator identification flag	TA1	LA2

In this case, the operator network identification information is preset identification information for identifying each provider network.

The MME 134 may advance the CSFB according to the TA where the terminal 100 is located and the LA mapped with the operator identification flag of the operator network to which the terminal 100 is subscribed, with reference to the mapping table as shown in Table 1.

In addition, the MME 134 may insert an operator identification flag into a predetermined bit among bits set as unused bits of the SPID and transmit the same to the eNodeB 132. For example, the MME 134 may transmit to the eNodeB 132 an Initial Context Modification Request that includes the SPID with the operator identification flag inserted.

In addition, the eNodeB 132 receives and stores the SPID from the MME 134, and when the CSFB is triggered later, inserts the frequency information corresponding to the operator identification flag included in the SPID into the RRCConnection Release Message, to the terminal 100. RRCConnection Release Message can be sent. Therefore, the terminal 100 attempts handover to the NodeB of the operator network to which the terminal 100 is subscribed according to the frequency information included in the RRCConnection Release Message. If the eNodeB 132 does not have a SPID in which an operator identification flag is inserted, the eNodeB 132 should include frequency information of all provider network NodeBs corresponding to the location of the terminal 100 in the RRCConnection Release Message. Accordingly, the terminal 100 causes a delay as the handover attempts according to the frequency information. Therefore, the mobile communication system according to an embodiment of the present invention can prevent the additional delay from occurring by making the terminal 100 attempt to handover only to the NodeB of the provider network.

The first provider network 110 and the second provider network 120 are networks supporting both a circuit switch (CS) scheme and a packet switched scheme, and include NodeBs 112 and 122, SGSNs 114 and 124, and Mobile switching center (MSC) 116, 126.

Here, NodeBs 112 and 122 are wireless access networks in the first operator network 110 and the second operator network 120, and are based on Asynchronous Transfer Mode (ATM), and the terminal 100 and the mobile communication core network (Core Network). It is located between) to transmit data and control information.

The MSCs 116 and 126 are connected to the MME 134 to provide a location update function of the terminal 100 to support the CSFB.

Communication interfaces used in each path from the terminal 100 via the NodeB 112, SGSN 114, and MSC 116 are described in detail in the known 3GPP standard, and thus, the general description of the communication interfaces is described herein. Detailed description thereof will be omitted.

2 is a flowchart illustrating an attach process for providing a circuit switched fallback in a mobile communication system according to an embodiment of the present invention.

Referring to FIG. 2, in step 210, the terminal 100 transmits an Attach Request to the MME 134.

In step 220, an attach procedure including an authentication and a location update process of the terminal 100 is performed. At this time, according to the LTE standard of the 3GPP, the Attach Procedure is known to include the authentication, location update, Context Setup, Modify Bearer process corresponding to the LTE network, step 220 is a process corresponding to the location update process of the LTE standard This can be done. Therefore, the details of the authentication and location update process of the LTE standard is a known matter, so a detailed description thereof will be omitted. At this time, the MME 134 may receive an Authentication Information Answer message including subscriber information from the HSS 136 during the authentication process defined in the standard, and may extract the SPID included in the subscriber information.

In step 230, the MME 134 requests a location update to the MSC corresponding to the LA matching the TA where the terminal 100 is located among the LAs of the operator network to which the terminal 100 subscribes, referring to the table according to Table 2 (Location Update). Send Request). For example, when the terminal 100 is located in TA1 and is a terminal receiving a service of the first provider network, the MME 134 may have an MSC corresponding to a carrier identification flag corresponding to the first operator and LA1 matching TA1. The location update request may be sent to 116.

In step 240, the MSC 116 performs a location update process of the operator's network to which the terminal 100 subscribes. At this time, the location update process of the operator network, which is the CS domain, is designated as a standard and is well known, and thus detailed description thereof will be omitted.

In step 250, the MSC 116 sends a Location Update Accept to the MME 134 upon completion of the location update.

In step 260, a context setup and modify bearer process according to the LTE standard is performed.

Therefore, the mobile communication system according to an embodiment of the present invention uses a table in which a carrier identification flag, TA, and LA are matched, so that the terminal 100 joins in a situation where a plurality of CS domain provider networks and a single LTE network are interworked. The attach process may be performed to the CS domain provider network.

3 is a call processing flowchart illustrating a process before a terminal is handed over when the calling terminal transmits the terminal to the idle terminal in the mobile communication system according to an embodiment of the present invention.

Referring to FIG. 3, in step 310, a paging signal is received according to a call connection request of an originating terminal, and the MME 134 transmits a paging signal to the eNodeB 132.

In step 320, the eNodeB 132 transmits a paging signal to the terminal 100, receives a paging response from the terminal 100, and transmits an Initial UE Message (Extended Service Request) to the MME 134.

In step 330, the MME 134 inserts a carrier identification flag into a bit predetermined in the SPID.

In step 340, the MME 134 transmits an Initial Context Modification Request to the eNodeB 132 indicating that the CSFB is required for the terminal 100. At this time, the Initial Context Modification Request may include an SPID including a business operator identification flag.

In step 350, the eNodeB 132 extracts and stores the SPID included in the Initial Context Modification Request.

In step 360, the eNodeB 132 transmits an Initial Context Modification Response to the MME 134.

In step 370, the eNodeB 132 performs a bearer modification process and transmits a UE Context release Request to the MME 134 indicating that the CSFB is triggered.

In step 380, the MME 134 transmits a UE context release command to the MME 134 requesting the progress of the CSFB.

In step 390, the eNodeB 132 transmits an RRCConnection message including frequency information corresponding to the carrier identification flag included in the SPID to the terminal 100. At this time, the eNodeB 132 may store frequency information corresponding to each operator identification flag in advance.

In step 395, the eNodeB 132 transmits UE Context release Complete to the MME 134.

Thereafter, the terminal 100 may be handed over to the NodeB 112 of the first provider network 110 or the second provider network 120 according to a known standard by referring to frequency information included in the RRCConnection Release Message. The terminal 100 transmits a paging response signal to the MSC 116 of the calling terminal through the NodeB 112 after the handover, and a call setup process between the calling terminal and the terminal 100 is performed.

Accordingly, the terminal 100 may receive only frequency information of a single operator through an RRCConnection Release Message, and may be connected to the NodeB 112 according to the corresponding frequency information. If the eNodeB 132 does not perform the process of storing the SPID, the eNodeB 132 cannot identify the CS domain operator of the terminal 100. Accordingly, the eNodeB 132 includes the frequency information for all operators in the RRCConnection Release Message to the terminal 100 and transmits it, and the terminal 100 attempts to sequentially connect to the NodeB 112 according to each frequency information. And there is a delay. Accordingly, the mobile communication system according to an embodiment of the present invention can reduce the delay incurred in the process of connecting with the NodeB 112 of the terminal 100 in the CSFB process when the multi-service provider network and a single LTE network is interworking. have.

So far I looked at the center of the embodiment for the present invention. Many embodiments other than the above-described embodiments are within the claims of the present invention. Those skilled in the art will appreciate that the present invention can be implemented in a modified form without departing from the essential features of the present invention. Therefore, the disclosed embodiments should be considered in descriptive sense only and not for purposes of limitation. The scope of the present invention is shown in the claims rather than the foregoing description, and all differences within the scope will be construed as being included in the present invention.

Claims

In a mobile communication system including a Long Term Evolution (LTE) network connected to a plurality of CS (Circuit Switched) domain operator network to provide a Circuit Switched FallBack (CSFB),

An eNodeB receiving a connection request from a terminal; And

Store a table matched with the carrier identification information, the tracking area (TA) and the location area (LA) for the terminal, and receives the connection request from the eNodeB to identify the operator of the operator subscribed to the terminal by referring to the table A mobility management entity (MME) for requesting a location update for the terminal to an MSC in charge of the LA corresponding to the TA where the terminal is currently located;

Mobile communication system comprising a.
According to claim 1,

When the MME receives a paging request from the MSC according to the outgoing call request of the other terminal, and transmits a paging request to the eNodeB,

The eNodeB transmits an access message including frequency information of NodeB controlled by the MSC to the terminal according to the paging request, so that the terminal is handed over from the eNodeB to the NodeB.
The method of claim 2,

When the MME receives the message requesting the CSFB from the terminal after transmitting the paging request to the eNodeB, and transmits the SPID to which the operator identification flag is inserted in a predetermined unused bit to the eNodeB,

The eNodeB is a mobile communication system, characterized in that for transmitting the access message containing the frequency information of the NodeB corresponding to the carrier identification flag included in the SPID to the terminal.
The method of claim 3, wherein

The MME performs an authentication process according to the connection request, and the mobile communication system, characterized in that for extracting the SPID from the message received from the HSS (HOME SUBSCRIBER SERVER) during the authentication process.
A method of supporting a CSFB in a mobile communication system including a Long Term Evolution (LTE) network connected to a plurality of CS (Circuit Switched) domain operator networks and providing a Circuit Switched FallBack (CSFB),

receiving, by the eNodeB, a connection request from a terminal and transmitting the connection request to a mobility management entity (MME);

Generating, by the MME, a table in which operator identification information, a tracking area (TA), and a location area (LA) of the terminal are matched; And

Requesting, by the MME, a location update request for the terminal to an MSC in charge of an LA corresponding to the operator identification information of the operator to which the terminal is subscribed to and the TA where the terminal is currently located with reference to the table;

CSFB support method comprising a.
The method of claim 5,

Receiving, by the MME, a paging request from the MSC according to an outgoing call request of another terminal;

Sending, by the MME, a paging request to the eNodeB; And

The eNodeB transmitting an access message including the frequency information of the NodeB controlled by the MSC according to the paging request to the terminal so that the terminal is handed over from the eNodeB to the NodeB;

CSFB support method further comprising.
The method of claim 6,

After the MME transmits a paging request to the eNodeB, when the MME receives a message requesting a CSFB from the UE, transmitting a SPID in which the operator identification flag is inserted into a predetermined unused bit to the eNodeB.

Include more,

The eNodeB transmits an access message including the frequency information of the NodeB controlled by the MSC according to the paging request to the terminal so that the terminal is handed over from the eNodeB to the NodeB, the eNodeB to the SPID And transmitting an access message including the frequency information of the NodeB corresponding to the service provider identification flag to the terminal.
The method of claim 7, wherein

After the eNodeB receives the connection request from the terminal and transmits to the MME,

And performing, by the MME, an authentication process according to the connection request, and extracting the SPID from a message received from a HSS (HOME SUBSCRIBER SERVER) during the authentication process.