KR102421645B1 - Method and apparatus for transmitting downlink data and uplink data in nb-iot system - Google Patents

Abstract

A method is provided for a network node to transmit downlink data. The network node generates downlink data for a terminal in a radio resource control (RRC) idle state. When the size of the downlink data is smaller than a reference value, the network node inserts the downlink data into a first paging message for transitioning the terminal to the RRC connected state. And the network node transmits the first paging message to the terminal through the base station.

Description

METHOD AND APPARATUS FOR TRANSMITTING DOWNLINK DATA AND UPLINK DATA IN NB-IOT SYSTEM

The present invention relates to a method and apparatus for transmitting downlink data and uplink data in a narrowband (NB)-IoT (internet of things) system.

NB (narrowband)-IoT (internet of things) refers to an Internet of Things system whose standardization work is in progress by the 3rd generation partnership project (3GPP), an international standard organization. NB-IoT is based on the existing long term evolution (LTE) system.

The characteristics of NB-IoT can be summarized in two ways. One of them is that the number of terminals is huge, and the other is that the amount of data that each terminal transmits and receives with the network is small.

While the existing LTE system requires a data transmission rate of tens to 100 Mbps or more depending on the characteristics of the service, NB-IoT has a characteristic that only a small amount of data is transmitted/received periodically (non).

In order for a terminal to access a network and receive a service, a number of message procedures between the base station and the terminal and a number of message procedures between the backbone network and the terminal are performed. The interface between the base station and the terminal is defined by a radio resource control (RRC) protocol, and the interface between the network and the terminal is defined by a non-access stratum (NAS) protocol.

The base station uses S1 application protocol (S1AP) to send and receive NAS messages to and from the network.

The NB-IoT system is making an effort to minimize the system load generated by this control message procedure. However, since the NB-IoT system borrows the procedure of the existing LTE system as it is, it still uses a complicated message procedure.

An object to be solved by the present invention is to provide a method and apparatus for simplifying a control message procedure for an NB-IoT system.

According to an embodiment of the present invention, a method is provided for a network node to transmit downlink data. The downlink data transmission method includes: generating downlink data for a terminal in a radio resource control (RRC) idle state; inserting the downlink data into a first paging message for transitioning the terminal to an RRC connected state when the size of the downlink data is smaller than a reference value; and transmitting the first paging message to the terminal through a base station.

The generating of the downlink data may include generating the downlink data having a non-access stratum (NAS) protocol data unit (PDU) form.

The downlink data included in the first paging message may be inserted into an RRC paging message by the base station that has received the first paging message.

Inserting the downlink data into the first paging message may include generating the first paging message for a narrowband (NB)-internet of things (IOT) system.

The generating of the downlink data may include applying integrity protection and encryption based on a NAS (non-access stratum) security key to the downlink data.

Also, according to another embodiment of the present invention, a method for transmitting uplink data by a terminal in a radio resource control (RRC) idle state is provided. The method for transmitting uplink data includes: generating uplink data; inserting the uplink data into an uplink common control channel (CCCH) message using the same resource as an RRC connection request message when the size of the uplink data is smaller than a reference value; and transmitting the uplink CCCH message to the base station.

Inserting the uplink data into the uplink CCCH message includes: generating the uplink CCCH message; and inserting the uplink data in the form of a non-access stratum (NAS) message into the uplink CCCH message.

The inserting of the uplink data into the uplink CCCH message may include inserting the identifier of the terminal into the uplink CCCH message.

The uplink data included in the uplink CCCH message may be inserted into an S1 application protocol (S1AP) message to be transmitted to a network node by the base station receiving the uplink CCCH message.

When the validity of the uplink data included in the S1AP message is verified through the identifier of the terminal by the network node that has received the S1AP message, the uplink data is can be delivered to the destination.

Inserting the uplink data into the uplink CCCH message may include generating the uplink CCCH message for a narrowband (NB)-internet of things (IOT) system.

Also, according to another embodiment of the present invention, a network node for a narrowband (NB)-IOT (internet of things) system is provided. The network node may include: a memory; and a processor controlling the memory.

The processor generates downlink data for a terminal in an RRC idle state in which a radio resource control (RRC) connection with a base station is released, and S1AP for transitioning the downlink data to an RRC connected state (S1 application protocol) may be inserted into a paging message, and the S1AP paging message may be transmitted to the base station.

According to an embodiment of the present invention, the control message procedure for the NB-IoT system can be simplified.

In addition, according to an embodiment of the present invention, downlink data and uplink data can be efficiently transmitted in the NB-IoT system.

1A and 1B are diagrams illustrating an attach procedure.
FIG. 2 is a diagram specifically illustrating an attach request procedure illustrated in FIG. 1A .
3 is a diagram illustrating a control message flow when data to be transmitted to a terminal in an RRC idle state is generated by a network.
4 is a diagram illustrating a downlink data transmission method according to an embodiment of the present invention.
5 is a diagram illustrating a procedure for a case in which data to be transmitted to a network by a terminal is generated.
6 is a diagram illustrating a method for transmitting uplink data according to an embodiment of the present invention.
7 is a diagram illustrating a computing device according to an embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those of ordinary skill in the art to which the present invention pertains can easily implement them. However, the present invention may be embodied in several different forms and is not limited to the embodiments described herein. And in order to clearly explain the present invention in the drawings, parts irrelevant to the description are omitted, and similar reference numerals are attached to similar parts throughout the specification.

In this specification, duplicate descriptions of the same components will be omitted.

Also, in this specification, when it is said that a certain element is 'connected' or 'connected' to another element, it may be directly connected or connected to the other element, but another element in the middle. It should be understood that there may be On the other hand, in the present specification, when it is mentioned that a certain element is 'directly connected' or 'directly connected' to another element, it should be understood that the other element does not exist in the middle.

In addition, the terms used herein are used only to describe specific embodiments, and are not intended to limit the present invention.

Also in this specification, the singular expression may include the plural expression unless the context clearly dictates otherwise.

Also, in this specification, terms such as 'include' or 'have' are only intended to designate that the features, numbers, steps, operations, components, parts, or combinations thereof described in the specification exist, and one or more It should be understood that the existence or addition of other features, numbers, steps, acts, components, parts, or combinations thereof, is not precluded in advance.

Also in this specification, the term 'and/or' includes a combination of a plurality of listed items or any of a plurality of listed items. In this specification, 'A or B' may include 'A', 'B', or 'both A and B'.

Also in the present specification, a terminal is a mobile terminal, a mobile station, an advanced mobile station, a high reliability mobile station, a subscriber station, It may also refer to a portable subscriber station, an access terminal, user equipment (UE), machine type communication device (MTC), etc., and may refer to a mobile terminal, a mobile station, an advanced It may include all or part of the functions of an established mobile station, a high-reliability mobile station, a subscriber station, a portable subscriber station, an access terminal, a user equipment, an MTC, and the like.

Also in the present specification, a base station (BS: base station) is an advanced base station (advanced base station), a high reliability base station (HR-BS), a Node B (NB: node B), an advanced Node B ( eNB: evolved node B), NR (new radio) Node B (eg, gNB), access point, radio access station, base transceiver station, MMR (mobile multihop relay) -BS, a relay station serving as a base station, a high reliability relay station serving as a base station, a repeater, a macro base station, a small base station, a femto base station, a home node B (HNB: home node B) , may refer to home eNB (HeNB), pico base station, micro base station, etc., advanced base station, HR-BS, NodeB, eNB, gNB, access point, radio access station, transceiver base station, MMR-BS, repeater, It may include all or part of the functions of a high-reliability repeater, repeater, macro base station, small base station, femto base station, HNB, HeNB, pico base station, micro base station, and the like.

Hereinafter, a method of operating the NB-IoT control message will be described. A description will be given of a technique for controlling a radio resource control (RRC) message and an S1 application protocol (S1AP) message for the NB-IoT system.

1A and 1B are diagrams illustrating an attach procedure. And Figure 2 is a diagram specifically showing the attach request procedure illustrated in Figure 1a.

In order for the terminal to access the network and receive a service, an attach procedure must be performed. The attach procedure is a procedure for a specific terminal to access a network, and is a procedure for determining whether a corresponding terminal is a valid terminal based on an identifier of the terminal stored in the network and granting access. The attach procedure consists of a total of two steps, one of which is to establish a wireless connection between the terminal and the base station, and the other is to perform a procedure such as authentication through a context exchange between the terminal and the network. Specifically, the attach procedure is defined as shown in FIGS. 1A and 1B below.

1A and 1B, network nodes (eg, a terminal (UE), a base station (eNB), a new mobility management entity (MME), an old MME/SGSN (serving general packet radio service support node)), and an equipment identity register (EIR) ), serving GW (gateway), PDN (packet data network) GW, PCRF (policy and charging rules function), HSS (home subscriber server), etc.) performed by the attach procedure is exemplified. Specifically, the procedures after the procedures illustrated in FIG. 1A are illustrated in FIG. 1B .

In particular, '1. Attach Request' procedure will be described in detail with reference to FIG. 2 .

The terminal (UE) transmits an RRC connection request message (eg, RRCConnectionRequest) to the base station (eNB) in order to request a wireless connection. Specifically, the terminal may transmit an RRCConnectionRequest message to the base station using signaling radio bearer (SRB)0, transparent mode (TM), and common control channel (CCCH).

The base station allocates radio resources to the terminal through an RRC connection establishment message (eg, RRCConnectionSetup) in response to the terminal's RRC connection request message. Specifically, the base station may transmit an RRCConnectionSetup message to the terminal using SRB0, TM, and CCCH.

When the terminal normally receives the RRC connection establishment message (eg, RRCConnectionSetup), it transmits an RRC connection establishment completion message (eg, RRCConnectionSetupComplete) to the base station in response to this. Specifically, the terminal may transmit the RRCConnectionSetupComplete message to the base station using SRB1bis, acknowledged mode (AM), and dedicated control channel (DCCH). In this case, the terminal includes a NAS message (eg, AttachRequest) for requesting a network connection in the RRC connection setup completion message (eg, RRCConnectionSetupComplete).

When the base station receives the RRC connection setup completion message (eg, RRCConnectionSetupComplete), the corresponding NAS message (eg, AttachRequest) is included in the S1AP message (eg, InitialUEMessage) and then the network (eg, evolved packet core (EPC), MME) ) is sent to

On the other hand, '3. Identification Request' procedure to '6. The 'Ciphered Options Request' procedure is a procedure between the terminal and the network, and is a procedure to check whether the terminal is valid or not. If this verification is successful, the '17. Initial Context Setup Request or Downlink NAS transport with Attach Accept' procedure or '19. Through the 'RRC connection Reconfiguration Complete' procedure, resources for transmitting and receiving actual user data are allocated and the procedure is terminated.

When the base station successfully receives the RRCConnectionSetupComplet message, the terminal is in an RRC connected state. This means that an RRC connection between the terminal and the base station is established.

When the attached terminal no longer receives the service, since there is no need to be connected to the base station, the RRC connection is released. In this case, the terminal is in the RRC idle (idle) state.

Since the UE in the RRC idle state is already in a state in which it is confirmed to the network through the attach procedure, when the UE in the RRC idle state performs access again, '3. Identification Request' procedure to '6. Ciphered Options Request' procedure is skipped.

Hereinafter, a procedure until the terminal in the RRC idle state receives a service (eg, data transmission/reception) will be described.

For two reasons, the UE in the RRC idle state transitions to the RRC connected state. One of them is a case in which data to be transmitted to the terminal exists by the network, and the other is a case in which the terminal itself determines that data should be transmitted to the network. For example, if the terminal is an electricity meter in the home, the former reason may correspond to a request from the server collecting electricity metering information to report the usage for a specific period to a specific terminal, and the latter reason may be a predefined This may correspond to a case in which the terminal determines that data should be transmitted at the reporting time (eg, the end of the month, etc.).

1. When data is generated from the network

3 is a diagram illustrating a control message flow when data to be transmitted to a terminal in an RRC idle state is generated by a network.

The network (eg, EPC) transmits a paging message to the base station (eg, eNB) in order to transition the UE in the RRC idle state to the RRC connected state.

The base station transmits an RRC paging message to the terminal (eg, UE) based on the paging message received from the network.

When the terminal receives the RRC paging message from the base station, it recognizes that the terminal itself needs to reconnect to the network. And 'RRCConnectionRequest' procedure to '10. After the 'InitialcontextSetupResponse' procedure is performed, the terminal receives downlink data from the network.

On the other hand, '7. InitialContextSetupRequest' procedure to '10. InitialContextSetupResponse' procedure is valid for LTE system. In the case of the NB-IoT system, '7. InitialContextSetupRequest' procedure to '10. InitialContextSetupResponse' procedure can be omitted.

Hereinafter, a method of simplifying the above procedures for the NB-IoT system will be described.

4 is a diagram illustrating a downlink data transmission method according to an embodiment of the present invention.

When the network (eg, EPC) transmits the paging message after recognizing that there is data (eg, first user data) to be transmitted to the terminal, the first user data may be included in the paging message.

When the base station (eg, eNB) receives the paging message from the network, the first user data included in the paging message may be included in the RRC paging message.

The terminal (eg, UE) receives the RRC paging message including the first user data from the base station. As a result, the terminal may receive downlink data using only the paging message.

Meanwhile, user data included in the paging message may have the same form as a NAS protocol data unit (PDU) defined in an existing standard (technical specification). This means that user data can be transmitted in any NAS message format.

The paging message is defined in 3GPP TS 36.331 (RRC) and 3GPP TS 36.413 (S1AP). A new paging message structure based on the S1AP paging message/RRC paging message defined in V13.3.0 is shown in Table 1 (S1AP paging) and Table 2 (RRC paging) below.

IE /Group Name Presence Range IE type and reference Semantics description Criticality Assigned Criticality Message Type M 9.2.1.1 YES ignore UE Identity Index value M 9.2.3.10 YES ignore UE Paging Identity M 9.2.3.13 YES ignore Paging DRX O 9.2.1.16 YES ignore CN Domain M 9.2.3.22 YES ignore List of TAIs One YES ignore >TAI List Item One .. <maxnoofTAIs> EACH ignore >>TAI M 9.2.3.16 - CSG Id List 0..1 GLOBAL ignore >CSG Id One .. <maxnoofCSGId> 9.2.1.62 - Paging Priority O 9.2.1.78 YES ignore UE Radio Capability for Paging O 9.2.1.98 YES ignore Assistance Data for Paging O 9.2.1.103 YES ignore Paging eDRX Information O 9.2.1.111 YES ignore Extended UE Identity Index Value O 9.2.3.46 YES ignore NB-IoT Paging eDRX Information O 9.2.1.115 YES ignore NAS PDU O 1..(maxPDU size) OCTET STRING YES ignore

The S1AP paging message for the downlink data transmission method illustrated in FIG. 4 may further include the 'NAS PDU' illustrated in Table 1, compared to the existing S1AP paging message.

Paging-NB ::= SEQUENCE {
pagingRecordList-r13 PagingRecordList-NB-r13 OPTIONAL, -- Need ON
systemInfoModification-r13 ENUMERATED {true} OPTIONAL, -- Need ON
systemInfoModification-eDRX-r13 ENUMERATED {true} OPTIONAL, -- Need ON
nonCriticalExtension SEQUENCE {} OPTIONAL
}

PagingRecordList-NB-r13 ::= SEQUENCE (SIZE (1..maxPageRec)) OF PagingRecord-NB-r13

PagingRecord-NB-r13 ::= SEQUENCE {
ue-Identity-r13 PagingUE-Identity,
dedicatedInfoNAS - r13 DedicatedInfoNAS
}

DedicatedInfoNAS ::= OCTET STRING

The RRC paging message for the downlink data transmission method illustrated in FIG. 4 may further include 'dedicatedInfoNAS-r13 DedicatedInfoNAS' illustrated in Table 2, compared to the existing RRC paging message.

Specifically, the NAS PDU configured in the S1AP paging message is mapped to the dedicatedInfoNAS-r13 parameter in the RRC paging message.

Due to the characteristics of the paging message, since multiple terminals may receive the same paging message, the NAS PDU of the S1AP paging message may be a packet to which NAS-level integrity protection and encryption are applied.

A method for a network node (eg, EPC) to transmit downlink data will be described as follows.

A network node (eg, EPC) may generate downlink data for a UE in an RRC idle state. Specifically, the network node (eg, EPC) may generate downlink data in the form of a NAS PDU. A network node (eg, EPC) may apply integrity protection and encryption based on a NAS security key to downlink data.

The network node (eg, EPC) may insert downlink data into a paging message for transitioning the UE to the RRC connected state. Specifically, when the size of downlink data (eg, a small amount of data) is smaller than the reference value, the network node (eg, EPC) may insert the downlink data into a paging message (eg, S1AP paging message). Specifically, the network node (eg, EPC) may generate a paging message for the NB-IOT system. Meanwhile, when the size of downlink data is larger than the reference value, the network node (eg, EPC) may perform the procedure illustrated in FIG. 3 .

A network node (eg, EPC) may transmit a paging message to the terminal through the base station. Specifically, downlink data included in the paging message of the network node (eg, EPC) may be inserted into the RRC paging message by the base station receiving the paging message of the network node (eg, EPC).

2. When data is generated from the terminal

5 is a diagram illustrating a procedure for a case in which data to be transmitted to a network by a terminal is generated.

A procedure for a case in which the UE in the RRC idle state transitions to the RRC connected state at the request of the UE (eg, the procedure illustrated in FIG. 5) and when the UE in the RRC idle state transitions to the RRC connected state by the request of the network The procedure for (eg, the procedure illustrated in FIG. 3) is almost similar, except that there is a difference in the paging message procedure (eg, the '1. paging' procedure and the '2. paging' procedure illustrated in FIG. 3).

Hereinafter, the UE omits the RRC connection establishment procedure (eg, '3. RRCConnectionRequest' procedure to '5. RRCConnectionSetupComplete' procedure) illustrated in FIG. 5 and directly transmits uplink data using only the RRC message. A method for transmitting uplink data will be described. . However, the size limitation of the uplink CCCH message among the RRC messages is not considered.

In order for the UE in the RRC idle state to transition to the RRC connection state, the first message that the UE in the RRC idle state transmits to the base station is an RRC connection request message (eg, RRCConnectionRequest), and the RRC connection request message (eg, RRCConnectionRequest) is based on the RRC standard. It belongs to the commercial uplink CCCH classification.

The RRC connection request message (eg, RRCConnectionRequest) is a message used to establish a wireless connection between the terminal and the base station, and includes the identifier (eg, ID) of the terminal or the reason why the terminal requests the connection.

6 is a diagram illustrating a method for transmitting uplink data according to an embodiment of the present invention.

As illustrated in FIG. 6 , an RRC data transfer request message (eg, RRCDataTransferRequest) according to an embodiment of the present invention may be used instead of the RRC connection request message (eg, RRCConnectionRequest). The RRC data transfer request message (eg, RRCDataTransferRequest) corresponds to a new uplink CCCH message. The structure of the RRC data transfer request message (eg, RRCDataTransferRequest) is shown in Table 3 below.

RRCDataTransferRequest ::= SEQUENCE {
dedicatedInfoNAS - r13 DedicatedInfoNAS
}

Specifically, the terminal (eg, UE) transmits an RRC data transfer request message (eg, RRCDataTransferRequest) including uplink data to the base station (eg, eNB). For example, the terminal may transmit uplink data in the form of a NAS message based on the dedicatedInfoNAS-r13 parameter to the base station. The NAS message based on the dedicatedInfoNAS-r13 parameter may include a terminal identifier (eg, international mobile subscriber identity (IMSI), international mobile station equipment identity (IMEI), etc.) so that the terminal can be identified by the network.

When the base station receives the RRC data transfer request message (eg, RRCDataTransferRequest) from the terminal, the information included in the RRC data transfer request message (eg, RRCDataTransferRequest) is included in the S1AP message (eg, UplinkNASTransport) and then the network (eg, EPC). Here, the UplinkNASTransport message may correspond to the InitialUEMessage message.

The network verifies the validity of the data included in the NAS message (or S1AP message) using the identifier of the terminal included in the NAS message (or S1AP message) (eg, UplinkNASTransport, InitialUEMessage) received from the base station, and the NAS message (or S1AP message) message) to the final destination.

A method for transmitting uplink data by a UE in an RRC idle state will be described as follows.

The terminal may generate uplink data.

When the size of uplink data (eg, a small amount of data) is smaller than the reference value, the UE may insert the uplink data into an uplink CCCH message (eg, RRCDataTransferRequest) using the same resource as the RRC connection request message. Specifically, the UE may generate an uplink CCCH message for the NB-IOT system, and may insert uplink data in the form of a non-access stratum (NAS) message into the uplink CCCH message. The UE may insert its own identifier into the uplink CCCH message. Meanwhile, when the size of uplink data is larger than the reference value, the terminal may perform the procedure illustrated in FIG. 5 .

The terminal may transmit an uplink CCCH message to the base station. Information (eg, uplink data, terminal identifier, etc.) included in the uplink CCCH message may be inserted into the S1AP message to be transmitted to the network node (eg, EPC) by the base station receiving the uplink CCCH message. When the validity of the uplink data included in the S1AP message is verified through the terminal identifier by the network node (eg, EPC) that has received the S1AP message, the uplink data is transmitted to the uplink data by the network node (eg, EPC). can be delivered to the destination of

7 is a diagram illustrating a computing device according to an embodiment of the present invention. The computing device TN100 of FIG. 7 may be a base station, a terminal, or an EPC described herein. Alternatively, the computing device TN100 of FIG. 7 may be a wireless device, a network node, a transmitter, or a receiver.

In the embodiment of FIG. 7 , the computing device TN100 may include at least one processor TN110 , a transmission/reception device TN120 connected to a network to perform communication, and a memory TN130 . Also, the computing device TN100 may further include a storage device TN140 , an input interface device TN150 , an output interface device TN160 , and the like. Components included in the computing device TN100 may be connected by a bus TN170 to communicate with each other.

The processor TN110 may execute a program command stored in at least one of the memory TN130 and the storage device TN140. The processor TN110 may mean a central processing unit (CPU), a graphics processing unit (GPU), or a dedicated processor on which methods according to an embodiment of the present invention are performed. The processor TN110 may be configured to implement procedures, functions, and methods described in connection with an embodiment of the present invention. The processor TN110 may control each component of the computing device TN100 .

Each of the memory TN130 and the storage device TN140 may store various information related to the operation of the processor TN110 . Each of the memory TN130 and the storage device TN140 may be configured as at least one of a volatile storage medium and a non-volatile storage medium. For example, the memory TN130 may include at least one of a read only memory (ROM) and a random access memory (RAM).

The transceiver TN120 may transmit or receive a wired signal or a wireless signal. In addition, the computing device TN100 may have a single antenna or multiple antennas.

On the other hand, the embodiment of the present invention is not implemented only through the apparatus and/or method described so far, and a program for realizing a function corresponding to the configuration of the embodiment of the present invention or a recording medium in which the program is recorded may be implemented. And, such an implementation can be easily implemented by those skilled in the art from the description of the embodiments of the present invention described above.

Although the embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements by those skilled in the art using the basic concept of the present invention as defined in the following claims are also presented. It belongs to the scope of the invention.

Claims (13)

delete delete delete delete delete A method for transmitting uplink data by a terminal in a radio resource control (RRC) idle state, the method comprising:
generating uplink data;
inserting the uplink data into an uplink common control channel (CCCH) message using the same resource as an RRC connection request message when the size of the uplink data is smaller than a reference value; and
Transmitting the uplink CCCH message to the base station in the RRC idle state
including,
The uplink CCCH message is transmitted when there is no RRC connection with the base station, and is a message different from the RRC connection request message. 7. The method of claim 6,
Inserting the uplink data into the uplink CCCH message comprises:
generating the uplink CCCH message; and
Inserting the uplink data in the form of a non-access stratum (NAS) message into the uplink CCCH message
Uplink data transmission method. 7. The method of claim 6,
Inserting the uplink data into the uplink CCCH message comprises:
inserting the identifier of the terminal into the uplink CCCH message
Uplink data transmission method. 7. The method of claim 6,
The uplink data included in the uplink CCCH message is inserted into an S1 application protocol (S1AP) message to be transmitted to a network node by the base station receiving the uplink CCCH message
Uplink data transmission method. 10. The method of claim 9,
When the validity of the uplink data included in the S1AP message is verified through the identifier of the terminal by the network node that has received the S1AP message, the uplink data is delivered to the destination
Uplink data transmission method. 7. The method of claim 6,
Inserting the uplink data into the uplink CCCH message comprises:
NB (narrowband) - comprising the step of generating the uplink CCCH message for the Internet of Things (IOT) system
Uplink data transmission method. delete delete

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