KR20180082163A - Terminal apparatus and method of cs fallback, base station and method for supporting cs fallback - Google Patents

Abstract

According to an embodiment of the present invention, disclosed is a circuit switched (CS) fallback method using a terminal. The CS fallback method comprises the steps of: receiving CS paging through a first operator network in a state of being connected to the first operator network; transmitting a radio resource control (RRC) access request message to a base station of the first operator network, and transmitting, to the base station, a public land mobile network (plmn) identifier of a second operator network to which a terminal has joined from a plmn identifier list received from the base station; receiving frequency information corresponding to the plmn identifier of the second operator network and an RRC connection release message from the base station; and responding to the CS paging on the basis of the received frequency information.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a terminal device and a CS fallback method using the same, and a base station and a CS fallback supporting method using the same.

The present invention relates to the field of communications. More specifically, the present invention relates to a method of CS fallback of a terminal and a method of supporting CS fallback of a base station.

Network fallback (hereinafter, referred to as CS fallback) in the 3GPP Evolved Packet System refers to a method of allocating resources in a long term evolution (LTE) Evolved UMTS Terrestrial Radio Access Network (E-UTRAN) (UEs) in a service area can receive a Circuit Switched (CS) service (e.g., a voice service, a video service, a short message service) by using network resources in a Circuit Switched (CS) (SMS), Location Services (LCS), and Unstructured Supplementary Service Data (USSD).

The CS fallback function is used when the CS service can not be provided through the EPS network.

For reference, EPS is a network in the form of all IP networks (All IP Network, AIPN), and it needs to be linked with IP Multimedia Subsystem (IMS) network in order to provide services such as voice and SMS. Therefore, if the EPS network does not support the IMS service or the IMS function can not be used, the CS fallback function should be used. The CS fallback function should be provided not only in the network but also in the terminal.

In the EPS network, the SGs interface is defined between the Mobility Management Entity (MME), which provides the mobility management function for the CS fallback function, and the MSC server. The SGs interface provides mobility management messages for the CS fallback function as well as sending / receiving of incoming / outgoing SMS messages. Specifically, a mobility management process such as a Combined EPS / IMSI Attach process for the CS fallback function, a Combined TA / LA (Tracking Area / Location Area) update process and a Detach process, a paging process from the MSC server to the MME for the CS fallback service, ) Process, and a process of transmitting an SMS message to / from the terminal or through the SGs interface.

A terminal device according to an embodiment of the present invention and a CS fallback method therefor, a base station and a CS fallback support method using the same, are intended to enable quick CS fallback of a terminal.

Also, a terminal device according to an embodiment of the present invention, a CS fallback method therefor, a base station and a CS fallback support method using the same can be applied to an LTE service in a network shared network, CS service in order to enable the use of the CS service.

A CS fallback method according to an embodiment of the present invention includes:

CLAIMS 1. A CS (circuit switched) fallback method by a terminal, the method comprising: receiving CS (circuit switched) paging through a first provider network in a state connected to a first provider network; And transmits a radio resource control (RRC) access request message to the base station of the first provider network, and transmits a plmn identifier of the second provider network, which is included in the public land mobile network (plmn) Transmitting to a base station; Receiving an RRC connection release message from the base station and frequency information corresponding to a plmn identifier of the second network; And responding to the CS paging based on the received frequency information.

The first provider network may be network-shared with the second provider network.

Wherein the step of transmitting the RRC connection request message and the plmn identifier of the second network includes: receiving an RRC connection setup message from the base station in response to the RRC connection request message; And transmitting a plmn identifier of the second network and an RRC connection setup completion message to the BS in response to the RRC connection setup message.

The step of receiving the frequency information may include receiving an RRC connection release message including the frequency information from the base station in response to the RRC connection setup completion message.

The step of responding to the CS paging may include a step of releasing the connection with the base station and accessing the base station of the second provider network based on the frequency information.

The plmn identifier list may include plmn identifiers of providers that share the first provider network.

A CS fallback support method according to another embodiment of the present invention includes:

A method of supporting CS fallback by a base station, the method comprising: broadcasting a plmn identifier list including a plmn identifier of a service provider network belonging to the service provider network to a cell area; Transmitting CS paging to a terminal located in the cell area; Receiving a plmn identifier from the terminal; And transmitting the frequency information corresponding to the received PLMN identifier to the UE so that the UE can respond to the CS paging.

The CS fallback support method may further include storing a plmn identifier of a provider network to which the service provider belongs and a plmn identifier of another provider network that shares the provider network to which the provider belongs.

A base station apparatus according to an embodiment of the present invention includes:

A memory for storing a plmn identifier list including a plmn identifier of a provider network to which the terminal belongs and a plmn identifier of another provider network that shares a provider network to which the provider network belongs; A broadcasting unit for broadcasting the PLMN identifier list to a cell area; And transmitting CS paging to a terminal located in the cell area, receiving one of the PLMN identifiers from the terminal, transmitting frequency information corresponding to the received PLMN identifier to the terminal, And a communication unit for enabling a response to the request.

A terminal apparatus according to an embodiment of the present invention, a CS fallback method therefor, and a base station and a CS fallback support method using the same can enable rapid CS fallback of a terminal.

Also, a terminal device according to an embodiment of the present invention, a CS fallback method therefor, a base station and a CS fallback support method using the same can be applied to an LTE service in a network shared network, CS service can be made available.

However, the terminal device according to an embodiment of the present invention and the CS fallback method, the base station, and the CS fallback support method using the terminal device according to the present invention are not limited to the above- May be understood by those skilled in the art to which the present invention belongs.

1 is a schematic diagram for explaining CS fallback according to an embodiment of the present invention.
2 is a flowchart for explaining CS fallback according to an embodiment of the present invention.
3 is a flowchart for explaining the operation of each configuration for CS fallback according to an embodiment of the present invention.
4 is an exemplary diagram showing a SIB1 message broadcast by a base station.
5 is an exemplary diagram showing an RRC connection setup completion message that the UE transmits to the base station.
6 is an exemplary diagram showing an RRC connection release message transmitted to a terminal that is a base station.
7 is a block diagram illustrating a configuration of a base station according to an embodiment of the present invention.

While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. It is to be understood, however, that the intention is not to limit the invention to the specific embodiments, but on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the accompanying drawings. In addition, numerals (e.g., first, second, etc.) used in the description of the present invention are merely an identifier for distinguishing one component from another.

Also, in this specification, when an element is referred to as being "connected" or "connected" with another element, the element may be directly connected or directly connected to the other element, It should be understood that, unless an opposite description is present, it may be connected or connected via another element in the middle.

In the present specification, a component represented by 'unit', 'module', or the like refers to a case where two or more components are combined into one component, or one component is divided into two or more ≪ / RTI > In addition, each of the components to be described below may additionally perform some or all of the functions of the other components in addition to the main functions of the component itself, and some of the main functions And may be performed entirely by components.

Hereinafter, exemplary embodiments according to the technical idea of the present invention will be described with reference to the drawings.

1 is a schematic diagram for explaining CS fallback according to an embodiment of the present invention.

In FIG. 1, reference numeral 115 denotes a cell area of the base station 110 of the first provider, and reference numeral 125 denotes a core network of the first provider. At least one of the cell area 115 of the base station 110 and the core network 125 of the first business entity is referred to as a first business network. Reference numeral 215 denotes a cell area of the base station 210 of the second business entity, and 225 denotes a core network of the second business entity. At least one of the cell area 215 of the base station 210 and the core network 225 of the second business entity is referred to as a second business network.

The terminal 300 is a terminal that is subscribed to the second business network, and can receive services in the first business network that the second business entity shares with the network. For example, the terminal 300 can receive the LTE data service in the first provider network.

The MS 300 is connected to the BS 110 of the first provider network and performs CS paging (hereinafter referred to as CS paging), which is transmitted through the MSC 220, the MME 120 and the BS 110, To the second provider network to which the user belongs through the CS fallback.

The terminal 300 accesses the base station 210 of the second provider according to the CS fallback and receives a CS service, for example, a voice service, a video service, a short message service, a location service, have.

The base station 110 transmits the frequency information of the second network to the terminal 300 so that the terminal 300 can quickly perform the CS fallback in accordance with the technical idea of the present invention. Will be described with reference to the following.

2 is a flowchart for explaining CS fallback according to an embodiment of the present invention.

In step S210, the terminal 300 receives the CS paging from the base station 110. [ Also, the terminal 300 may receive a public land mobile network (PLMN) identifier list from the base station 110. The plmn identifier list may include a plmn identifier of the first carrier to which the base station 110 belongs and a plmn identifier of another carrier that shares the first carrier network.

In step S220, the MS 300 confirms the plmn identifier of the second carrier to which the MS 300 belongs in the plmn identifier list as the CS paging is received, and transmits the RRC connection request message and the confirmed plmn identifier to the BS 110 do.

The terminal 300 is in an idle state in the cell area of the base station 110 and can transmit an RRC connection request message to the base station 110 of the first provider when the CS paging is received.

In step S230, after the RRC connection is approved, the terminal 300 receives the RRC connection release message and the frequency information corresponding to the plmn identifier of the second provider from the base station 110. [

The base station 110 may previously store frequency information corresponding to all plmn identifiers included in the plmn identifier list. Accordingly, the base station 110 may extract the frequency information corresponding to the plmn identifier received from the terminal 300 in step S220, and transmit the extracted frequency information to the terminal 300. [

In step S240, the terminal 300 can access the second provider network and receive the CS service based on the received frequency information.

According to an embodiment of the present invention, frequency information is transmitted from the base station 110 to the terminal 300, so that the terminal 300 does not need to perform a separate operation for checking the frequency for CS fallback, Bags can be made available.

3 is a flowchart for explaining the operation of each configuration in CS fallback according to an embodiment of the present invention.

In step S30, the MS 300 receives CS paging through the MSC 220 of the second business entity, the MME 120 of the first business entity, and the BS 110.

In step S31, the first base station 110 broadcasts an SIB1 message to the cell area. The SIB1 message may include a plmn identifier of a third party that shares the first provider's plmn identifier with the first provider's network, for example, the second provider. Depending on the implementation, the order of steps S30 and S31 may be changed.

4 is a diagram illustrating an SIB1 message broadcasted by the base station 110. As shown in FIG. 4, the SIB1 message may include a list of PLMN identifiers 400. FIG.

3, in step S32, the MS 300 transmits an RRC connection request message to the BS 110 according to CS paging. In step S33, the MS 300 receives an RRC connection setup message .

In step S34, the terminal 300 determines whether the first business network is in a shared state, that is, whether the second business entity to which the first business network is affiliated shares the first business network. The terminal 300 can check whether the plmn identifier of the second provider exists in the plmn identifier list.

If the first business entity network is not shared, that is, if the second business entity does not share the first business entity network, the RRC connection establishment completion message is transmitted to the base station 110 in step S35.

In step S36, when the first business entity network is shared, that is, when the second business entity is sharing the first business entity network, the terminal 300 transmits an RRC connection setup completion message together with the plmn identifier of the second business entity To the base station 110. The RRC connection establishment completion message may include an extended service request for the CS response. 5 shows an RRC connection setup completion message that the MS 300 transmits to the BS 110. As shown in FIG. 5, the RRC connection setup complete message includes the PLMN identifier information 500 of the second operator can do.

In step S37, the BS 110 transmits an initial UE message including an extended service request to the MME 120. In step S38, the MME 120 requests the MSC 220 to perform a service.

In step S39, the BS 110 stores the PLMN identifier received from the UE 300 in step S36, and receives the S1-AP initial UE context setup request from the MME 120 in step S40. The S1-AP initial UE context setup request may include a message allowing or disallowing a CS fallback trigger. In step S41, the base station 110 transmits an S1-AP initial UE context setup response message to the MME 120. [

In step S42, the base station 110 determines whether a CS fallback trigger is allowed from the MME 120, and if not, transmits an RRC connection release message to the terminal 300 in step S43. In this case, since the CS fallback trigger is not allowed from the MME 120, the frequency information is not included in the RRC disconnect message.

In step S44, if the CS fallback trigger is allowed, the base station 110 transmits an RRC disconnect message including frequency information for CS fallback to the UE 110. [ 6 shows an RRC connection release message transmitted from the BS 110 to the MS 300. As shown in FIG. 6, the RRC connection release message includes frequency information 600 to be connected to the MS 300 .

In step S45, the base station 110 transmits the S1-AP UE Context Release Request to the MME 120, and receives the S1-AP UE Context Release Response from the MME 120 in step S46.

In step S47, the MS 300 searches for a frequency based on the frequency information received from the BS 110. In step S48, the MS 300 transmits data to the MSC 220, Proceed with the setup process. After step S48, the terminal 300 can receive a CS service through the base station 120 and the MSC 220. [

7 is a block diagram showing a part of the configuration of the base station 110 according to an embodiment of the present invention.

Referring to FIG. 7, a base station 110 according to an embodiment of the present invention may include a memory 111, a broadcasting unit 113, a communication unit 115, and a control unit 117.

The memory 111, the broadcasting unit 113, the communication unit 115, and the control unit 117 may be implemented by at least one processor and may operate according to programs stored in the memory 111. [

The memory 111 stores a plmn identifier list including a plmn identifier of the provider network to which it belongs and a plmn identifier of another provider network that shares the provider network to which the plmn identifier belongs. Also, the memory 111 may previously store frequency information corresponding to each plmn identifier included in the plmn identifier list.

The broadcasting unit 113 broadcasts a plmn identifier list to the cell area.

The communication unit 115 transmits CS paging to the terminal 300 located in the cell area when the CS paging for one of the terminals 300 is received from the MME 120, And receives one of the plmn identifiers in response.

If the CS trigger is allowed by the MME 120, the communication unit 115 transmits the frequency information corresponding to the plmn identifier received from the terminal 300 to the terminal 300, CS service can be provided as a basis.

Meanwhile, the embodiments of the present invention described above can be written in a program that can be executed in a computer, and the created program can be stored in a medium.

The medium may include, but is not limited to, storage media such as magnetic storage media (e.g., ROM, floppy disks, hard disks, etc.), optical reading media (e.g., CD ROMs,

It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present invention as defined by the following claims. You will understand. It is therefore to be understood that the above-described embodiments are illustrative in all aspects and not restrictive.

110, 210: base station
111: Memory
113: Broadcasting section
115:
117:
120: MME
220: MSC
300: terminal

Claims (9)

In a CS (circuit switched) fallback method by a terminal,
Receiving CS (circuit switched) paging through a first network in a first network connected to the first network;
And transmits a radio resource control (RRC) access request message to the base station of the first provider network, and transmits a plmn identifier of a second provider network, which is included in the list of public land mobile network (plmn) Transmitting to a base station;
Receiving an RRC connection release message from the base station and frequency information corresponding to a plmn identifier of the second network; And
And responding to the CS paging based on the received frequency information.
The method according to claim 1,
And the first provider network is network-shared with the second provider network.
The method according to claim 1,
Wherein the step of transmitting the RRC connection request message and the PLMN identifier of the second network includes:
Receiving an RRC connection setup message from the base station in response to the RRC connection request message; And
And transmitting a PLMN identifier of the second network and an RRC connection setup completion message to the BS in response to the RRC connection setup message.
The method of claim 3,
Wherein the step of receiving the frequency information comprises:
And receiving an RRC connection release message including the frequency information from the base station in response to the RRC connection setup completion message.
5. The method of claim 4,
Wherein the responding to the CS paging comprises:
Releasing the connection with the base station and connecting to the base station of the second provider network based on the frequency information.
The method according to claim 1,
The plmn identifier list includes:
And the PLMN identifiers of the providers sharing the first provider network.
A method for supporting CS fallback by a base station,
Broadcasting a plmn identifier list including a plmn identifier of a network of a service provider to the cell area;
Transmitting CS paging to a terminal located in the cell area;
Receiving a plmn identifier from the terminal; And
And transmitting the frequency information corresponding to the received PLMN identifier to the UE to allow the UE to respond to the CS paging.
8. The method of claim 7,
The CS fallback supporting method includes:
Further comprising the step of storing a plmn identifier of a provider network to which the terminal belongs and a plmn identifier of another provider network that shares the provider network to which the provider belongs.
A memory for storing a plmn identifier list including a plmn identifier of a provider network to which the terminal belongs and a plmn identifier of another provider network that shares a provider network to which the provider network belongs;
A broadcasting unit for broadcasting the PLMN identifier list to a cell area; And
Wherein the mobile terminal transmits CS paging to a terminal located in the cell region, receives one of the PLMN identifiers from the terminal, transmits frequency information corresponding to the received PLMN identifier to the terminal, Wherein the base station apparatus comprises:

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