KR20130107381A - Non access stratum based small data transmission - Google Patents

Abstract

PURPOSE: A non access stratum (NAS) based small data transmitting method is provided to efficiently transmit a small amount of machine type communication (MTC) data between user equipment (UE) and a service capability server (SCS) which are used for an MTC in a long term evolution (LTE) mobile communication network. CONSTITUTION: An evolved node B (eNodeB) (302) receives a service request NAS message which includes information from UE (301) (S310). The information indicates that the message includes a small amount of data. The eNodeB capsulates the NAS message. The eNodeB transmits the capsulated NAS message to a mobility management entity (MME) (303) through a control plane (S320). An NAS authentication/security procedure is performed (S330). The MME extracts a small amount of data from the NAS message, adds an identifier of UE, and delivers to an MTC interworking function (MTC-IWF) (305) (S340). In case identifier information of UE is delivered to an international mobile station identity (IMSI), the MTC-IWF changes identifier information of transmission UE into an external identifier in the IMSI.

Description

NAS-based small data transmission method {Non access stratum based Small data transmission}

The present invention relates to a data transmission method that can efficiently transmit a small amount of data through a Non Access Stratum (NAS) message in an EPS (Evolved Packet System), a LTE (Long Term Evolution) mobile communication network.

The mobile communication network consists of a radio access network (RAN) and a core network (Core network), and the 3G mobile communication core network includes a circuit switched (CS) domain and a packet switched (PS) domain. The LTE mobile communication core network includes only the packet switched domain.

A PS only subscription refers to a subscription for providing all services (e.g., packet bearer service, SMS) subscribed to by a user equipment (UE) through the packet switched domain only.

On the other hand, when transmitting and receiving a small amount of data, such as MTC, when applying the existing service processing scheme, there has been an overhead problem in the use of signaling resources.

The present invention devised to solve the above problems is to provide a NAS-based data transfer procedure that can efficiently transmit a small amount of MTC data between the UE and the SCS server used for MTC in LTE mobile communication network. .

In addition, an object of the present invention is to support an overload control function that can effectively cope with an overload situation that may occur due to an increase in MTC data traffic transmitted through a signaling radio bearer.

NAS-based small data transmission method according to an embodiment of the present disclosure provides a NAS-based data transfer procedure that can efficiently transmit a small amount of MTC data between the UE and the SCS server used for MTC in LTE mobile communication network. .

In addition, the NAS-based small data transmission method according to an embodiment of the present specification supports an overload control function that can effectively cope with an overload situation that may occur due to an increase in MTC data traffic transmitted through a signaling radio bearer.

As described above, the present invention provides a new data radio bearer by providing a NAS-based data transfer procedure through MTC IWF to efficiently transmit a small amount of MTC data between a UE and an SCS server used for MTC in an LTE mobile communication network. The effect is that a small amount of MTC data can be transmitted without a connection. In addition, since a large amount of UEs used for MTC may increase, a small amount of MTC data may be classified and processed in an overload situation of signaling radio bearers, thereby stably operating a network.

1 shows a 3GPP communication network structure diagram for MTC communication according to an embodiment of the present specification.
2 is a view showing a connection configuration of the control plane in the configuration of the present invention according to an embodiment of the present specification.
3 is a diagram illustrating a method of transmitting small data through a service request NAS message according to an embodiment of the present invention.
4 is a diagram illustrating a method of transmitting small data through a TAU NAS message or a new NAS according to an embodiment of the present invention.
FIG. 5 is a diagram illustrating a method of transmitting small data through a General NAS transport message according to an embodiment of the present invention.
FIG. 6 is a diagram illustrating a method for transmitting less mobile calls through a service request NAS message according to the present invention in an idle mode according to an embodiment of the present invention.
7 is a diagram illustrating an RRC connection establishment according to an embodiment of the present invention.

Hereinafter, some embodiments of the present invention will be described in detail with reference to exemplary drawings. In adding reference numerals to the components of each drawing, it should be noted that the same reference numerals are assigned to the same components as much as possible even though they are shown in different drawings. In the following description of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear.

In addition, in describing the component of this invention, terms, such as 1st, 2nd, A, B, (a), (b), can be used. These terms are intended to distinguish the constituent elements from other constituent elements, and the terms do not limit the nature, order or order of the constituent elements. When a component is described as being "connected", "coupled", or "connected" to another component, the component may be directly connected or connected to the other component, Quot; may be "connected," "coupled," or "connected. &Quot;

In the present specification, the description will be focused on LTE or LTE-A (LTE Advanced) communication. This is one embodiment of a packet switched domain, and embodiments of the present invention are applicable in the packet switched domain.

Machine type communication (MTC) is a form of data communication that represents machine to machine communication where one or more entities do not necessarily require human interaction.

1 shows a 3GPP communication network structure diagram for MTC communication according to an embodiment of the present specification.

In the 3GPP architecture for the MTC of FIG. 1, end-to-end communication between an MTC application in a mobile communication terminal (UE) and an MTC application in an application server (AS) of an external network of a mobile communication network is performed in a 3GPP system. And services are provided by the Service Capability Server (SCS). The Direct Model in the figure shows a model in which the AS directly connects to the operator network without using SCS to perform user plane communication with the UE.

The Indirect Model represents a model in which the AS indirectly connects to the operator's network through the services of the SCS to perform indirect user-plane communications with the UE or to use additional services such as device triggering.

Hybrid model represents the simultaneous use of direct and indirect models between AS and UE.

Looking at each individual constituting the present invention as follows.

UE (User Equipment) means a mobile communication terminal. In addition, the UE may host one or more MTC applications.

RAN (Radio Access Network) means a wireless access network.

MSC (Mobile Switching Center) means circuit switched based mobile switch.

The Serving GPRS Support Node (SGSN) refers to a packet-switched mobile switcher that performs mobility management (GSMN) functions, and the Gateway GPRS Support Node (GGSN) is an entity that provides interworking between a GPRS network and an external packet-switched network. to be.

A mobility management entity (MME) refers to an entity on a control plane for supporting a mobility management function in an evolved packet system (EPS).

S-GW (Serving Gateway) is a gateway that terminates the interface to the E-UTRAN, P-GW (PDN Gateway) is a gateway that terminates the interface to the PDN.

Service Capability Server (SCS) is an entity connected to a 3GPP network to communicate with UEs used for MTC, and is a device of Home Public Land Mobile Network (HPLMN) for device triggering. Connect with MTC IWF or SMS-SC. SCS can be used by one or more MTC applications.

The Short Message Service-Service Center (SMS-SC) is an entity that performs a function of relaying, storing, and transmitting a short message between an entity (e.g. UE) that transmits and receives a short message.

Home Subscriber Server (HSS) is a master database for users. It is an entity that contains subscription-related information needed to support session processing in network entities.

MTC-IWF (InterWorking Function) is an entity that performs a function of relaying or translating a signaling protocol used to operate a specific function in a mobile communication network through a Tsp with an SCS server.

In Figure 1 there are several reference points between the entities. In each case, Tsp is a reference point for control plane signaling between SCS and MTC IWF, and T4 is a reference point between SMS-SC and MTC IWF in a home mobile communication network.

Meanwhile, T5a is a reference point between MTC-IWF and serving SGSN, T5b is a reference point between MTC-IWF and serving MME, and T5c is a reference point between MTC-IWF and serving MSC. S6m is also a reference point between the MTC-IWF and the HSS / HLR.

As described above, UEs used for MTC periodically transmit and receive data with an MTC application server through a mobile communication network. In this case, the plurality of MTC devices have a feature of transmitting and receiving only a small amount of data (small data). In the long run, the number of UEs used for MTC to be accommodated through mobile networks is expected to exceed 100 times that of ordinary mobile terminals, requiring the efficient transmission of small amounts of data caused by large UEs used for MTC. There is.

In the LTE (Long Term Evolution) mobile communication network (EPS), data transmission is performed through a service request procedure. This is accompanied by the download and radio bearer establishment of the radio resource control (RRC) security context to the eNB. If the large UEs used for MTC are for one small data packet transmission, these procedures can result in inefficient radio resource utilization.

Techniques for solving this problem may be as follows.

First, a method of transmitting a small amount of MTC data using a generic NAS transport message of the LTE mobile communication network.

Generic NAS transport message is a NAS message used to carry protocol messages from various applications between the MME and the UE in an encapsulated form, and can carry a small amount of MTC data through the Generic NAS transport message. However, this method may be used only in the connected mode (EMM-Connected or ECM-Connected) in which the UE is attached to the EPS and there is a signaling connection between the UE and the MME. The signaling connection between the UE and the MME consists of an RRC connection and an S1-MME connection.

In another method, the UE transmits a small amount of MTC data using a new NAS message including MTC data.

In this method, a new NAS Packet Data Unit (PDU) includes Short Message Service (SMS) Relay Layer Protocol (RP) -DATA containing MTC data, or IP packets containing MTC data, and RRC Connection Setup Complete. Passed through the NAS container in the message. The message-type of the NAS message is a tracking area update request (TAU), and is transmitted through SMS-SC or SGW through MME without RRC context download and radio bearer setup. However, this method requires a separate processing procedure for distinguishing between new NAS message and TAU request message in MME, and must support SMS function or packet forwarding function of user plane in MME.

As described above, the conventional technology for transmitting a small amount of data in the LTE mobile communication network is performed through a service request procedure, and thus a radio resource is accompanied by an RRC security context and a radio bearer establishment. Consumption, UE can be attached to EPS, can only be used in EMM-Connected mode where there is a signaling connection between UE and MME, SMS message delivery function or user plane forwarding function to MME, etc. There was a problem that should support additional. In addition, due to the small amount of data transmission technology described above, when a large amount of signaling traffic increases, a separate overload control function is not provided, thereby causing overload or congestion due to a small data transmission through the signaling bearer. There was a problem that the network could become unstable.

In order to solve this problem, an object of the present specification is to provide a NAS-based data transfer procedure capable of efficiently transmitting a small amount of MTC data between an UE and an SCS server used for MTC in an LTE mobile communication network.

In addition, an object of the present invention is to support an overload control function that can effectively cope with an overload situation that may occur due to an increase in MTC data traffic transmitted through a signaling radio bearer.

2 is a view showing a connection configuration of the control plane in the configuration of the present invention according to an embodiment of the present specification.

While performing the network attach procedure, the UE may exchange an indication of a small amount of data transmission capability with the MME. The small amount of data transmission capability of the UE may be preconfigured with subscription information in the HSS. The small data information elements included in the subscription information include 'small transmission size', 'small number of data that can be sent in a chain', and 'small data transmission cycle'. ',' Received SCS server identifier 'and the like. The small data size may be used based on a maximum size of a typical SMS or a value corresponding to a maximum size of an Ethernet-based IP packet (about 1500 bytes) or a constant maximum payload size. If a small amount of data is standardized and used, the small amount of data may not be included in the subscription information.

The small number of data that can be chained at one time represents the maximum number of small amounts of data that can be chained and sent via NAS messages. If the application of the UE used for MTC wants to transmit a small amount of data, the small amount of data is fragmented into the small amount of data described above, concatenated into one NAS message, or sent. Multiple NAS messages may be sent with one small amount of data fragmented. When the application of the UE used for MTC fragments the small amount of data to be transmitted to the small amount of data described above, the small amount of data exceeds the maximum number of the small amount of data. The network can deliver this through the normal service request procedure, rather than through the NAS message.

A small amount of data transmission period / frequency indicates a period / frequency of sending and receiving a small amount of data without transmitting data on the user plane. When the UE or the network delivers data more frequently than a preconfigured small amount of data transmission period, the UE or the network may transmit the data through the general service request procedure instead of the NAS message.

While performing the Tracking Area Updater (TAU procedure), the UE may exchange an indication of a small amount of data transmission capability with the MME.

3 is a diagram illustrating a method of transmitting small data through a service request NAS message according to an embodiment of the present invention.

S310) When the UE 301 application (eg MTC application) wants to deliver a rarely occurring amount of data below the predefined data amount through the NAS message, the UE 301 services the eNodeB 302. Send the request NAS message encapsulated in an RRC message.

The NAS message may include an indication for indicating that the NAS message is a NAS message including a small amount of data. The UE 301 may display a NAS message display in which the NAS message includes a small amount of data by using device property information elements. In this case, the device attribute information may use a low priority access priority or may define and use a new information element.

Alternatively, the UE 301 may display a NAS message indication in which the NAS message includes a small amount of data by using a new protocol discriminator information element. Alternatively, the UE 301 may define a new NAS message type information for data transmission through a service request NAS message or display a NAS message indicating that the NAS message includes a small amount of data. Display information may be defined and displayed. Alternatively, the UE 301 may display the NAS message indication including the small amount of data in the NAS message in combination with the protocol identifier information and the NAS message type information. Alternatively, the UE 301 may display a NAS message indication in which the NAS message includes a small amount of data by defining new information elements. The NAS message may include the small amount of data. It may not include an indication to indicate that the containing NAS message.

The NAS message may be a plain text message or an encrypted message. In the case of encrypting a NAS message, the NAS message may be transmitted by including a key set identifier (KSI), a sequence number, and a message authentication code (MAC), and then decrypted by the MME 303.

The RRC message for establishing an RRC connection between the UE 301 and the eNodeB 302 is RRC Connection Request (UE-> eNodeB) (S710), RRC Connection Setup (eNodeB-> UE) (S720), and RRC ConnectionSetupComplete as shown in FIG. The message is delivered in the order of (UE-> eNodeB) (S730).

The RRC connection request includes S-TSI (S-Temporary Mobile Subscriber Identity). S-TMSI is a temporary mobile subscriber identifier for an efficient wireless signaling procedure and is composed of MMM (MME code) and M-TIMSI which is a mobile communication terminal identifier in MME 303.

If the UE 301 wants to send a small amount of data below a predefined data amount, the RRC establishment cause is 'MO DATA' used for user plane radio resource request or uplink signaling. Without setting, you can define and set new indicators to indicate sending a small amount of data through signaling. Alternatively, the cause of the RRC configuration can be set to MO Signaling. Even if the service request is for sending a small amount of data through signaling, if the UE 301 is set to NAS signaling low priority, the RRC setting cause can be set to 'Delay tolerant'. have.

If an overload occurs in the eNodeB 302 or exceeds the UE 301's small data transfer allowance or aggregated small data transfer allowance, a new indication to indicate sending a small amount of data. If the child is set, the eNodeB 302 may transmit an RRC Connection Reject message to the UE 301 for the RRC Connection Request. In case of RRC Connection Reject, it is possible to limit the communication for a certain time by setting the back off timer.

The eNodB transmits an RRC Connection Setup message to the UE 301 to allocate a signaling radio bearer component resource to be used by the UE 301, and the UE 301 transmits an RRC Connection Setup Complete message to inform the completion of the RRC connection. The Service Request NAS message including the small amount of data is sent in the Dedicated NAS Information field (DedicatedInfoNAS) of the RRC Connection Setup message.

S320) The eNodeB 302 forwards the NAS message to the MME 303. NAS messages are sent encapsulated in S1-AP: Intitial UE Message.

If an overload occurs in the MME 303, or if the UE 301's small data transfer allowance or aggregated small data transfer allowance is exceeded, this indicates that the NAS message is a NAS message containing a small amount of data. If it includes an indication to bet, the MME 303 may send a Service Request Reject message to the UE 301. In case of Service Request Reject due to overload, it is possible to limit the communication for a certain time by setting the back off timer.

Even if the MME 303 fails to process an indication to indicate that the NAS message is a NAS message containing a small amount of data, the Service Request Reject message may be transmitted to the UE 301, in which case the UE 301 may The general service request procedure can be used to transmit data.

If the service request NAS message is a NAS message that contains a small amount of data, the user plane radio bearer may not be set up (omit steps 4-12 in section 5.3.4.1 of 3GPP TS 23.401).

If the service request NAS message is a NAS message containing a small amount of data, the UE 301 or the network may release all EPS bearers. Alternatively, if the service request NAS message is a NAS message containing a small amount of data, the UE 301 or the network deactivates all EPS bearer contexts locally without peer to peer signaling between the network and the UE).

S330) 3GPP TS 23.401 The NAS authentication / security procedure of Section 5.3.10 may be performed. Step S330 may be omitted.

S340) The MME 303 extracts a small amount of data from the NAS message and adds an identifier of the UE 301 and transfers it to the MTC-IWF 305. In this case, when the identifier of the UE 301 uses the MSISDN, the identifier of the UE 301 which transmits a small amount of data may use the MSISDN, and when the external identifier other than the MSISDN is used, the IMSI may be used. Can be. Alternatively, when using an external identifier other than MSISDN, the external identifier may be used as it is.

The identifier of the SCS server that will receive the small amount of data may be communicated by the UE 301 with the small amount of data in the NAS message and used by the MME 303. Alternatively, the SCS (whether or not the UE 301 includes the small amount of data in the NAS message and does not forward it, or whether the UE 301 includes the small amount of data in the NAS message and forwards it, will not be able to send it. 306 The identifier of the server may be stored in the HSS 304 to use the information configured in the MME 303 on a network attach procedure, or may be stored in the HSS 304 so that the MME 303 may use the MTC-IWF ( 305 may use information obtained from the HSS 304 when performing data transmission. The information of the HSS 304 may use the SCS 306 server identifier information allowing device triggering to the UE 301 on the device triggering subscription information of the UE 301. The information of the HSS 304 may be separate subscription information for transmitting a small amount of data.

The address information of the MTC-IWF 305 to carry the message of the UE 301 may be preconfigured or stored in the HSS 304 and configured in the MME 303 on a network attach procedure, or the HSS 304 ), When the MME 303 wants to perform data transmission to the MTC-IWF 305, it can query from the HSS (304). As another method, the MME 303 may determine through a DNS query by using the external identifier information of the UE 301 retrieved from the HSS 304.

S350) When the identifier information of the UE 301 is transmitted to IMSI, the MTC-IWF 305 changes the identification information of the transmitting UE 301 from IMSI to external identifier information and receives the SCS (received with a small amount of data). 306) Deliver a small amount of data using the server identifier as the destination address. If the SCS 306 server identifier has not been received from the MME 303, the SCS 306 server identifier of the UE 301 or the MTC-IWF 305 preconfigured in the MTC-IWF 305 is sent to the HSS 304. The subscription information of the UE 301 is inquired, and a small amount of data is delivered using the received SCS 306 server identifier of the UE 301 as a reception address.

When the identifier information of the UE 301 is transmitted using external identifier information such as MSISDN, the MTC-IWF 305 uses external identifier information such as MSISDN as the identification information of the transmitting UE 301, and a small amount of data. A small amount of data is delivered using the SCS 306 server identifier received as the destination address. If the SCS 306 server identifier has not been received from the MME 303, the SCS 306 server identifier of the UE 301 or the MTC-IWF 305 preconfigured in the MTC-IWF 305 is sent to the HSS 304. The subscription information of the UE 301 is inquired, and a small amount of data is delivered using the received SCS 306 server identifier of the UE 301 as a reception address.

If the MTC-IWF 305 fails to transmit to the SCS 306 server, the MTC-IWF 305 may store a message to forward. Alternatively, if the MTC-IWF 305 fails to transmit to the SCS 306 server, if the MTC-IWF 305 supports SMS-SC and T4 interfaces, then the MTC-IWF 305 may be SMS-SC. You can also create a short message and send it to the SMS-SC for storage by the SMS-SC.

The MTC-IWF 305 generates CDR information including MSISDN or external identifier information and SCS 306 identification information.

S360) The MTC-IWF 305 forwards the delivery result report to the MME 303.

S370 ~ S380 MME 303 delivers the delivery result report to the UE (301). At this time, the delivery result report may use a Downlink NAS Transport NAS message. The NAS message including the delivery result report may be included in an RRC connection Release message. Alternatively, the above delivery result report may be sent in a new RRC message for delivery result report.

In the process of transmitting a small amount of data using the service request, the UE 301 may transmit a service request message and start an associated timer (e.g. T3417). In this case, when receiving a Downlink NAS Transport NAS message delivered as a delivery result report, the related timer may be stopped. Alternatively, a new service request confirmation message may be defined and delivered from the MME 303 to the UE 301, thereby stopping the related timer.

4 is a diagram illustrating a method of transmitting small data through a TAU NAS message or a new NAS according to an embodiment of the present invention.

S410) If the UE 401 application (eg MTC application) wants to deliver a rarely occurring amount of data less than or equal to the predefined data amount through the NAS message, the UE 401 may send a small amount of data to the eNodeB 402. NAS messages containing a large amount of data are encapsulated in RRC messages and sent. The NAS message may include an indication for indicating that the NAS message is a NAS message including a small amount of data. The UE 401 may display a NAS message display in which the NAS message includes a small amount of data by using device property information elements. In this case, the device attribute information may use a low priority access priority or may define and use a new information element.

Alternatively, the UE 401 may display a NAS message indication in which the NAS message includes a small amount of data using a new protocol discriminator information element. As another method, the UE 401 may define a new NAS message type information for data transmission through a TAU NAS message or a new NAS message type information for the NAS message display including the small amount of data. An information element may be defined and displayed. As another method, the UE 401 may define and display a NAS message type in which the NAS message includes a small amount of data by defining new NAS message type information.

Alternatively, the UE 401 may display the NAS message indication including the small amount of data in the NAS message in combination with the protocol identifier information and the NAS message type information. Alternatively, the UE 401 may define a new information element by displaying a NAS message indication in which the NAS message includes a small amount of data. The NAS message may not include an indication to indicate that the NAS message includes the small amount of data.

The NAS message may be a plain text message or an encrypted message. When encrypting a NAS message, it may be transmitted and sent including a Key Set Identifier (KSI), a sequence number, and a message authentication code (MAC), which may be decrypted by the MME 403.

RRC connection request includes S-TMSI. If the UE 401 wants to send a small amount of data below a predefined data amount, the RRC establishment cause may be set to 'MO Signaling' used in the TAU NAS message. Alternatively, the RRC configurator can define and set a new indicator to indicate sending a small amount of data through signaling. Even if the service request is for sending a small amount of data through signaling, if the UE 401 is set to NAS signaling low priority, the RRC setting cause can be set to 'Delay tolerant'. have.

If an overload occurs in the eNodeB 402, or exceeds the UE 401's small data transfer allowance or aggregated small data transfer allowance, a new indication to indicate sending a small amount of data. When setting the ruler, the eNodeB 402 may transmit an RRC Connection Reject message to the UE 401 for the RRC Connection Request. In case of RRC Connection Reject, it is possible to limit the communication for a certain time by setting the back off timer.

The eNodB transmits an RRC Connection Setup message to the UE 401 to allocate a signaling radio bearer configuration resource to be used by the UE 401, and the UE 401 transmits an RRC Connection Setup Complete message to inform the completion of the RRC connection. The TAU Request NAS message including the small amount of data may be included in the Dedicated NAS Information field (DedicatedInfoNAS) of the RRC Connection Setup message.

Alternatively, a new NAS message including the small amount of data may be included in the Dedicated NAS Information field (DedicatedInfoNAS) of the RRC Connection Setup message.

S420) The eNodeB 402 forwards the NAS message to the MME 403. NAS messages are sent encapsulated in S1-AP: Intitial UE Message.

If an overload occurs in the MME 403, or if the UE 401's small data transfer allowance or aggregated small data transfer allowance is exceeded, this indicates that the NAS message is a NAS message containing a small amount of data. The MME 403 may send a reject message via a TAU Reject message or a new NAS message or a reject message via a Downlink NAS Transport message to the UE 401 if it includes an indication to bet.

Reject Response to TAU Reject or New NAS Message Due to Overload If you receive a reject message via a NAS message or a Downlink NAS Transport message, you can also limit the communication for a certain period of time by setting a backoff timer.

If the MME 403 fails to process the indication to indicate that the NAS message is a NAS message containing a small amount of data, the reject message may be sent to the UE 401 via a TAU Reject message or a Downlink NAS Transport message. In this case, the UE 401 may enable data transmission through a general service request procedure.

S430) 3GPP TS 23.401 The NAS authentication / security procedure of Section 5.3.10 may be performed. Step 3 may be omitted.

S440-S460) is the same as step S340-S360 in FIG.

S470-S480) The MME 403 forwards the delivery result report to the UE 401. In this case, the delivery result report may use a Downlink NAS Transport NAS message. Alternatively, the delivery result report may use a TAU accept message. The NAS message including the delivery result report may be included in the RRC connection Release message. Alternatively, the above delivery result report may be sent in a new RRC message for delivery result report.

In the process of transmitting a small amount of data using the service request, the UE 401 may transmit a TAU request message or a new NAS message and start an associated timer (eg T3430). In this case, when receiving a Downlink NAS Transport NAS message delivered as a delivery result report, the related timer may be stopped. Alternatively, the TAU accept message may be transferred from the MME 403 to the UE 401 to stop the related timer.

FIG. 5 is a diagram illustrating a method for transmitting NAS transport message-less data according to an embodiment of the present invention. FIG.

In the idle mode, the UE 501 may transfer a small amount of MTC data using a NAS message between the UE 501 and the SCS 506 server used for MTC using the transmission method described in FIG. 3 or 4. Can be. In the connected (EMM-Connected or ECM-Connected) mode in which a signaling connection exists between the UE 501 and the MME 503, a small amount of data may be transmitted using a Generic NAS transport message.

S510) In the connected mode, when the UE 501 wants to deliver a rarely occurring amount of data below the predefined data amount in the UE (501 MTC application) through the NAS message, the UE 501 may send an eNodeB 502. ) Encapsulates a NAS message containing a small amount of data into an RRC message. The NAS message may include an indication for indicating that the NAS message is a NAS message including a small amount of data. The UE 501 may display a NAS message display in which the NAS message includes a small amount of data by using device property information elements. In this case, the device attribute information may use a low priority access priority or may define and use a new information element.

Alternatively, the UE 501 may define a new generic message container type and use a NAS message indication in which the NAS message includes a small amount of data.

The NAS message may be a plain text message or an encrypted message. In the case of encrypting a NAS message, it may be transmitted and sent including a Key Set Identifier (KSI), a sequence number, and a message authentication code (MAC), and then decrypted by the MME 503.

If an overload occurs in the eNodeB 502, or exceeds the UE 501's small data transfer allowance or aggregated small data transfer allowance, a new indication to indicate sending a small amount of data. If the child is set, the eNodeB 502 may delay or drop the RRC message described above.

S520. The eNodeB 502 forwards the NAS message to the MME 503. If an overload occurs in the MME 503, or exceeds the UE 501's small data transfer allowance or aggregated small data transfer allowance, this indicates that the NAS message is a NAS message containing a small amount of data. The MME 503 may send a reject message via the Downlink NAS Transport message to the UE 501 if it includes an indication to bet. The MME 503 may deliver an acknowledgment message after forwarding the message to the SCS 506 server without transmitting a rejection message through the Downlink NAS Transport message to the UE 501.

When receiving a reject message via a Downlink NAS Transport message due to overload, a backoff timer may be set to limit communication for a certain period of time. Even if the MME 503 fails to process an indication to indicate that the NAS message is a NAS message containing a small amount of data or via a Downlink NAS Transport message, a reject message may be sent to the UE 501, in which case The UE 501 may enable sending data through the general service request procedure.

S540-S560. It is the same as step S340-S360 of FIG.

S570- S580. The MME 503 delivers the delivery result report to the UE 501. At this time, the delivery result report may use a Downlink NAS Transport NAS message. The NAS message including the delivery result report may be included in an RRC connection Release message. Alternatively, the above delivery result report may be sent in a new RRC message for delivery result report.

In the process of transmitting a small amount of data using the service request, the UE 501 may transmit an Uplink NAS transport message and start a related timer. In this case, when receiving a Downlink NAS Transport NAS message delivered as a delivery result report, the related timer may be stopped.

FIG. 6 is a diagram illustrating a method for transmitting less mobile calls through a service request NAS message according to the present invention in an idle mode according to an embodiment of the present invention.

S610) Steps 1-5 of the device triggering procedure described in 3GPP TS 23.682 v.0.2.0, section 5.2.1 and mobile incoming little data can be initiated.

The device triggering payload may include MTC data to be delivered to the UE 601.

The MTC-IWF 605 selects T5 triggering through the MME 603 by using UE capabilities and serving MME capabilities that have been inquired from the HSS, and sends a trigger payload including device MTC data to the serving MME 603. To pass.

S620-S630) starts a paging procedure. The paging message may provide an indication that there is little data to send via the downlink NAS message. To do this, you can set the RRC cause to MO Signaling. Alternatively, the RRC configurator can define and set a new indicator to indicate sending a small amount of data through signaling.

In response to paging, the UE initiates a service request procedure.

When the MME 603 needs to transmit a small amount of data through a NAS message, the MME 603 receiving the service request message from the UE 601 may prevent the user plane radio bearer from being set up. (3GPP TS 23.401 5.3 Steps 4 through 12 in Section .4.1)

S650-S660) A small amount of data is transmitted to the UE 601 through a downlink NAS transport message.

S670-S680) Send Uplink NAS Transport delivery confirmation message. The UE 601 may forward with an indication to allow the eNodeB 602 to release the RRC connection.

S690-S699) delivers a delivery report to the SCS 606 server.

The above description is merely illustrative of the technical idea of the present invention, and those skilled in the art to which the present invention pertains may make various modifications and variations without departing from the essential characteristics of the present invention. Therefore, the embodiments disclosed in the present invention are intended to illustrate rather than limit the scope of the present invention, and the scope of the technical idea of the present invention is not limited by these embodiments. The scope of protection of the present invention should be construed according to the following claims, and all technical ideas falling within the scope of the same shall be construed as falling within the scope of the present invention.

Claims (1)

Receiving a service request NAS (non-access stratum) message including information indicating that the message includes a small amount of data from the terminal; And
And encapsulating the NAS message and transmitting the encapsulated NAS message to a mobility management entity through a control plane.

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