KR102337555B1 - Method and apparatus for transmitting and receiving data using multilink - Google Patents

Abstract

The present disclosure relates to a communication technique that converges a 5G communication system for supporting a higher data rate after a 4G system with IoT technology, and a system thereof. The present disclosure provides intelligent services (eg, smart home, smart building, smart city, smart car or connected car, healthcare, digital education, retail business, security and safety related services, etc.) based on 5G communication technology and IoT-related technology. ) can be applied to
A communication method using multi-link in a wireless communication system according to various embodiments of the present disclosure includes: acquiring multi-link control information; distributing transmission data to each link based on the multi-link control information; and simultaneously or selectively transmitting the distributed transmission data to each link. However, it is not limited to the above embodiment, and other embodiments are possible.

Description

Method and apparatus for transmitting and receiving data using multi-link in a wireless communication system {METHOD AND APPARATUS FOR TRANSMITTING AND RECEIVING DATA USING MULTILINK}

The present invention relates to a multilink network transmission system capable of transmitting data simultaneously or selectively using a plurality of network paths composed of the same or heterogeneous RAT (Radio Access Technology) in a wireless communication system.

Efforts are being made to develop an improved 5G communication system or pre-5G communication system in order to meet the increasing demand for wireless data traffic after commercialization of the 4G communication system. For this reason, the 5G communication system or the pre-5G communication system is called a system after the 4G network (Beyond 4G Network) communication system or the LTE system after (Post LTE). In order to achieve a high data rate, the 5G communication system is being considered for implementation in a very high frequency (mmWave) band (eg, such as a 60 gigabyte (60 GHz) band). In order to alleviate the path loss of radio waves and increase the propagation distance of radio waves in the ultra-high frequency band, in the 5G communication system, beamforming, massive MIMO, and Full Dimensional MIMO (FD-MIMO) are used. ), array antenna, analog beam-forming, and large scale antenna technologies are being discussed. In addition, for network improvement of the system, in the 5G communication system, an evolved small cell, an advanced small cell, a cloud radio access network (cloud radio access network: cloud RAN), an ultra-dense network (ultra-dense network) , Device to Device communication (D2D), wireless backhaul, moving network, cooperative communication, Coordinated Multi-Points (CoMP), and interference cancellation Technology development is underway. In addition, in the 5G system, FQAM (Hybrid FSK and QAM Modulation) and SWSC (Sliding Window Superposition Coding), which are advanced coding modulation (Advanced Coding Modulation: ACM) methods, and FBMC (Filter Bank Multi Carrier), NOMA, which are advanced access technologies, (non orthogonal multiple access), and sparse code multiple access (SCMA) are being developed.

On the other hand, the Internet is evolving from a human-centered connection network where humans create and consume information to an Internet of Things (IoT) network that exchanges and processes information between distributed components such as objects. Internet of Everything (IoE) technology, which combines big data processing technology through connection with cloud servers, etc. with IoT technology, is also emerging. In order to implement IoT, technology elements such as sensing technology, wired and wireless communication and network infrastructure, service interface technology, and security technology are required. , M2M), and MTC (Machine Type Communication) are being studied. In the IoT environment, an intelligent IT (Internet Technology) service that collects and analyzes data generated from connected objects and creates new values in human life can be provided. IoT is a field of smart home, smart building, smart city, smart car or connected car, smart grid, health care, smart home appliance, advanced medical service, etc. can be applied to

Accordingly, various attempts are being made to apply the 5G communication system to the IoT network. For example, technologies such as sensor network, machine to machine (M2M), and MTC (Machine Type Communication) are implemented by 5G communication technologies such as beamforming, MIMO, and array antenna. will be. The application of cloud radio access network (cloud RAN) as the big data processing technology described above can be said to be an example of convergence of 5G technology and IoT technology.

It is a technology for distributing and aggregating multiple links of LTE and WiFi paths in the transport layer. A method for properly merging is known.

In the existing multi-link distribution and merging technology, it is difficult to quickly reflect the link status of different access networks in the transport layer or the application layer, and it is applicable only to the TCP of the transport layer or the HTTP protocol of the application layer, so the supported protocols are limited. to be.

Accordingly, an object of the present invention is to provide a multi-link support system that can effectively utilize the transmission paths of a plurality of access networks in a 4G network and a next-generation mobile communication network such as 5G, which is currently under standard discussion.

A communication method using a multi-link in a wireless communication system according to an embodiment of the present invention includes: obtaining multi-link control information; distributing transmission data to each link based on the multi-link control information; It may include transmitting the distributed transmission data to each link simultaneously or selectively.

In a wireless communication system supporting multi-link according to an embodiment of the present invention, an electronic device acquires a transceiver for transmitting and receiving a signal, and multi-link control information, and based on the multi-link control information, transmits data, respectively. It may include at least one processor that distributes the distributed transmission data to the links of , and controls to transmit the distributed transmission data to each link simultaneously or selectively.

According to various embodiments of the present disclosure, path selection may be enabled according to an operator's operation policy, an application flow type, and a state of each access network path. Accordingly, it is possible to distribute and merge traffic through multi-links regardless of the type of the transport layer or the application layer, thereby providing load balancing and transmission speed improvement of a specific access network. In addition, it is possible to provide the access network status, flow, and subscriber information of the wireless network, and path selection and merging according to the operator policy.

1 is a diagram illustrating the concept of a multilink support system according to an embodiment of the present invention.
FIG. 2 illustrates an example in which the multi-link support system according to an embodiment of the present invention is applied to a cellular wireless network including 4G and 5G links.
3 is a diagram illustrating a packet header format of a multilink adaptation layer of a multilink support system according to an embodiment of the present invention.
4A is a diagram for explaining a change in a connection state of a terminal in a multilink support system according to an embodiment of the present invention.
4B is a diagram illustrating a specific example of a change in a connection state of a terminal in a multilink support system according to an embodiment of the present invention.
4C is a diagram for explaining an operation option according to a connection state of a terminal in a multilink support system according to an embodiment of the present invention.
5 is a flowchart illustrating a process of initial connection to a 4G network according to an embodiment of the present invention.
6 is a flowchart illustrating a process in which a second connection is made to 5G in a state in which there is a 4G connection according to an embodiment of the present invention.
7A is a diagram illustrating a part of Attach Request message content of a NAS (Non-Access Stratum) message.
7B is a diagram illustrating the configuration of a UE network capability information element.
7C is a diagram illustrating a part of the MS network capability value field.
8A is a flowchart illustrating a multilink data transmission method according to an embodiment of the present invention.
8B is a flowchart illustrating a method for receiving multilink data according to an embodiment of the present invention.
9A is a diagram illustrating an example of control information exchange between MLAP layers according to an embodiment of the present invention.
9B is a diagram illustrating a first type of control message according to an embodiment of the present invention.
9C is a diagram illustrating a second type of control message according to an embodiment of the present invention.
10A is a diagram illustrating another example of control information exchange between MLAP layers according to an embodiment of the present invention.
10B is a diagram illustrating an extended NAS message according to an embodiment of the present invention.
10c is a diagram defining a message type for a newly defined multilink management according to an embodiment of the present invention.
10D is a diagram illustrating a configuration of a Link status change information element according to an embodiment of the present invention.
10E is a diagram illustrating a value of a Link status change information element according to an embodiment of the present invention.
10f is a diagram showing the configuration of a path characteristic feedback information element according to an embodiment of the present invention.
10g is a view showing the value of a path characteristic feedback information element according to an embodiment of the present invention.
11 is a diagram illustrating another example of control information exchange between MLAP layers according to an embodiment of the present invention.
12A is a diagram schematically illustrating a configuration of an electronic device supporting multi-link according to an embodiment of the present invention.
12B is a diagram illustrating components of a multilink adaptation layer in a multilink support system according to an embodiment of the present invention.
13A is a diagram illustrating an example of measuring unidirectional delay for each link in a multilink support system according to an embodiment of the present invention.
13B is a diagram illustrating another example of measuring unidirectional delay for each link in a multilink support system according to an embodiment of the present invention.
14A is a diagram illustrating an example of a traffic distribution scheme of a multilink support system according to an embodiment of the present invention.
14B is a diagram illustrating another example of a traffic distribution scheme of a multilink support system according to an embodiment of the present invention.
15 is a flowchart illustrating a method of reordering received data in a multilink support system according to an embodiment of the present invention.

Hereinafter, the present invention will be described with reference to the accompanying drawings. The present invention can be made various changes and can have various embodiments, specific embodiments are illustrated in the drawings and the related detailed description is described. However, this is not intended to limit the present invention to specific embodiments, and should be understood to include all modifications and/or equivalents or substitutes included in the spirit and scope of the present invention. In connection with the description of the drawings, like reference numerals have been used for like components.

Expressions such as “including” or “may include” that may be used in the present invention indicate the existence of the disclosed function, operation, or component, and do not limit one or more additional functions, operations, or components. In addition, in the present invention, terms such as "comprises" or "have" are intended to designate that the features, numbers, steps, operations, components, parts, or combinations thereof described in the specification exist, but one or more It is to be understood that this does not preclude the possibility of addition or presence of other features or numbers, steps, operations, components, parts, or combinations thereof.

In the present invention, expressions such as “or” include any and all combinations of words listed together. For example, "A or B" may include A, may include B, or may include both A and B.

In the present invention, expressions such as "first," "second," "first," or "second," may modify various elements of the present invention, but do not limit the elements. For example, the above expressions do not limit the order and/or importance of corresponding components. The above expressions may be used to distinguish one component from another. For example, both the first user device and the second user device are user devices, and represent different user devices. For example, without departing from the scope of the present invention, a first component may be referred to as a second component, and similarly, a second component may also be referred to as a first component.

When an element is referred to as being “connected” or “connected” to another element, it is understood that it may be directly connected or connected to the other element, but other elements may exist in between. it should be On the other hand, when it is said 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.

Terms used in the present invention are only used to describe specific embodiments, and are not intended to limit the present invention. The singular expression includes the plural expression unless the context clearly dictates otherwise.

Unless defined otherwise, all terms used herein, including technical and scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Terms such as those defined in commonly used dictionaries should be interpreted as having a meaning consistent with the meaning in the context of the related art, and should not be interpreted in an ideal or excessively formal meaning unless explicitly defined in the present invention. does not

In the present invention, 4G and 5G are described as the first link and the second link as an example of the multi-link, but the present invention is not limited thereto, and it can be constructed using various RATs (Radio Access Technology) of the same or different types. You will understand well.

An "electronic device" in the present invention may include a user device and a core device supporting a multilink adaptation layer.

1 is a diagram illustrating the concept of a multilink support system according to an embodiment of the present invention.

There are a plurality of links (Link-A, Link-B, and Link-C) 110 in a specific section between the user node 100 and the Internet 120 that provides application services, and there are multiple links located on both sides of these links. Link adaptation layers 105 and 115 may utilize multiple links to provide data transmission in a number of ways. Here, the plurality of links (Link-A, Link-B, and Link-C) 110 is the same type or different types of radio access technology (Radio Access Technology) (eg, LTE, 5G, WiFi) It can be provided using

FIG. 2 illustrates an example in which the multi-link support system according to an embodiment of the present invention is applied to a cellular wireless network including 4G and 5G links.

There are two links 210 through a 4G NB (Node B) 215 and a 5G NB 220 between a user equipment (UE), for example, a terminal 200 and a core equipment 230 , and these Multilink Adaptation Protocol (MLAP) 205 and 230 serving as a multilink adaptation layer to provide a multilink service through a link are included in the terminal 200 and the core device 230 . The terminal 200 may receive an application service from the Internet 235 using the two links 210 .

MLAP deployed in the core network may be included in the Gateway (GW) node of the core of 4G or 5G. For convenience of explanation, an Evolved Packet Core (EPC) node of the core network including MLAP, which is a multi-link adaptation layer, is later for convenience of explanation. Let's call it ML-GW.

According to an embodiment of the present invention, the MLAP layer of the receiving end may estimate the path characteristics for each link and transmit it to the MLAP layer of the transmitting end. In addition, the MLAP layer of the transmitter may perform flow-based or packet-based path selection. The path selection may be determined according to policy information, subscriber information, ISP information, service and content type as well as path characteristic information. Also, the MLAP layer of the terminal may acquire radio state information for each link and share it with the MLAP of the core device. The radio state information may also be used for path selection of the MLAP layer. On the other hand, the terminal or the core device may operate as a transmitting end or a receiving end, respectively, depending on whether it is an uplink or a downlink.

MLAP operations of the transmitting end and the receiving end according to various embodiments of the present invention will be described below. In the present specification, it is assumed that both the terminal and the core device are capable of supporting multilink, and whether to support multilink may be determined through initial NAS signaling. For backward compatibility, the MLAP layer bypasses if one side is not supported. In a state in which both are supported, the MLAP layer creates an MLAP entity for each bearer of each terminal.

The following shows the function of the MLAP entity of the transmitter.

- Sequence numbering: MLAP SN (Sequence Number) management

- Time stamping: timestamp information can be added as an option

- Header compression (ROHC)

- Add MLAP header: Add header containing MLAP SN information

- Multi-link routing: Perform multi-link routing such as splitting/switching according to the current link connection status and policy

The operation of the MLAP entity of the transmitter to perform the above function is as follows.

- Link selection: Determines the link and operation option to be used according to link preference for service, available link, UE status, operation policy, etc.

- Header compression (ROHC): Since MLAP header processing is impossible in PDCP, ROHC is performed in advance in the MLAP layer. In PDCP, ROHC is not performed if the MLAP header is present.

- MLAP header processing: MLAP header is added in the format shown in FIG. 3 below

- Multi-link routing: distribution of data traffic based on path characteristic information provided by the MLAP entity at the receiving end

3 is a diagram illustrating a packet header format of a multilink adaptation layer of a multilink support system according to an embodiment of the present invention. As an example, the content of the field may be as follows.

- D/C (1 bit): data or control

- State (2 bits): single-link or multi-link, etc.

- R: Reserved

- MLAP SN (18 bits): MLAP sequence number

- (Optional Timestamp field can be added)

The following shows the functions of the MLAP entity at the receiving end.

- Path monitoring: Calculate bandwidth or delay of each link

- Link availability monitoring: monitoring for newly available or unusable links

- Remove MLAP header: Remove MLAP header and update related information

- Reordering: Reordering the entire packet according to the MLAP SN

- Header decompression: Compressed header decompression

The operation of the MLAP entity at the receiving end to perform the above function is as follows.

- Path monitoring: Estimate link bandwidth. Relative one-way delay per link can be calculated when Timestamp option is added

- Link availability monitoring: By repeatedly measuring the radio signal and connection status of each link, it is possible to determine which links are newly available or unavailable.

- Reordering: Perform reordering based on MLAP SN

The MLAP entity of the receiving end may determine the path state and link state and transmit it to the MLAP entity of the receiving end. A detailed information delivery method will be described in detail below.

4A is a diagram for explaining a change in a connection state of a terminal in a multilink support system according to an embodiment of the present invention.

In a multi-link system, a separate radio resource control (RRC) exists for each link, and thus connection management is managed separately for each link. However, the connection state of the terminal may be integrated and managed as shown in FIG. 4A .

The Disconnected state 400 indicates a state in which neither 4G nor 5G is connected. When the connection to either 4G or 5G is completed, the terminal in the disconnected state 400 enters the connected state 405, and it manages which link it is attached to as a separate internal variable. The connection state is the same as the existing RRC/ECM (EPS Session Management) state, and there are Idle and Connected states for each link.

4B is a diagram illustrating a change in a terminal state in more detail. Each transition step (1 to 8) of the diagram occurs when the following event occurs.

1: 4G attach/service request in 4G and 5G idle state

2: 5G attach/service request in 4G and 5G idle state

3: 4G connection, 5G attach/service request in 5G idle state

4: 4G attach/service request in 4G idle, 5G connected state

5: 4G detach/inactivity/RLF in 4G and 5G connected state

6: 5G detach/inactivity/RLF in 4G and 5G connected state

7: 4G connection, 4G detach/inactivity/RLF in 5G idle state

8: 4G idle, 5G detach/inactivity/RLF in 5G connection state

FIG. 4C shows operation options that can be performed when actual traffic occurs based on the change (transition) of the terminal state.

For example, if only one link is attached (eg, 4G EMM-Registered or 5G EMM-Registered), transmission is performed if the corresponding link is RRC-Connected, and paging is performed if the link is RRC-Idle. (radio) Allocates resources.

On the other hand, both links may be attached. If both links are RRC-Connected, data transmission can be split and performed. If one is Connected and the other is Idle, options such as i) transmitting data only through the connected link, ii) waking up the idle link while transmitting data through Connected (paging), and performing splitting when both are connected do. Lastly, if both are idle, options such as i) waking up only one link and performing data transmission based on user preference and policy, and ii) performing splitting after both paging are possible.

According to an embodiment of the present invention, the attachment procedure of a link that is first connected and a link that is additionally connected in a state in which any one link is connected is slightly different.

5 is a flowchart illustrating a process of initial connection to a 4G network according to an embodiment of the present invention.

In step 541 , the UE 500 may establish a 4G RRC connection with the 4G-NB 505 . In step 543, the terminal 500 may transmit an attach request to the 4G-NB 505, and in step 545, the 4G-NB 505 sends an initial UE message including information of the attach request to the NG-MME (New It may be transmitted to a Generation-Mobility Management Entity) 515 . The attach request and the initial UE message may further include terminal capability information (ML-Capability) related to multilink support.

In step 547, the NG-MME 515 may detect that it is the first connection, check the ML-capability included in the Attach Request message, and proceed with ML-activation. And, in steps 549 and 551, the 4G-NAS processing block of the NG-MME 515 may interwork with the HSS 530 to perform a network authentication process. And, in step 553, the NG-MME 515 may complete the 4G-NAS setup with the terminal 500. In step 555, the NG-MME 515 may inform the HSS 530 that the corresponding UE has accessed itself.

Thereafter, in steps 557 to 563, the NG-MME 515 transmits a Create Session Request to the ML-GW 520, thereby 4G bearer through the ML-GW 520 and the P-GW 525. (bearer) can be created. In step 565, the NG-MME 515 may transmit an initial context setup request to the 4G-NB 505, and the 4G-NB 505 upon receiving it may transmit an Attach Accept to the terminal 500 in step 567. . The 4G-NB 505 may transmit an initial context setup response to the NG-MME 515 in step 569, and the terminal 500 may transmit an Attach Complete to the NG-MME 515 in step 571. Thereafter, the NG-MME 515 may perform bearer modification with the ML-GW 520 in step 573 .

6 is a flowchart illustrating a process in which a second connection is made to 5G in a state in which there is a 4G connection according to an embodiment of the present invention.

In step 641 , the UE 600 may establish a 5G RRC connection with the 5G-NB 610 . In step 643, the terminal 600 may transmit an attach request to the 5G-NB 610, and in step 645, the 5G-NB 610 sends an initial UE message including information of the attach request to the NG-MME (New Generation-Mobility Management Entity) 615 . The attach request and the initial UE message may further include terminal capability information (ML-Capability) related to multilink support.

In step 647 , the NG-MME 615 may check ML-capability included in the Attach Request message to internally perform 4G connection and link addition. In steps 649 and 651, the 5G-NAS processing block of the NG-MME 615 can perform a network authentication process in conjunction with the HSS 630 in a similar manner, and in step 653, the 5G-NAS setup with the terminal 600 is performed. can be completed

In this case, the NG-MME 615 detects that it is the second connection, and does not send a session creation request to the ML-GW 620 . Instead, the NG-MME 615 binds to the existing 4G connection by performing a newly defined Create Link step with the ML-GW 620 in steps 655 and 657, and lower E-RAB (E-UTRAN Radio Access Bearer) ) can only create connections. The NG-MME 615 may send and receive Create Link request and response messages with the ML-GW 620 , and the messages are a terminal identifier (eg, UE-IP) and a 4G bearer identifier (eg, 4G EPS Bearer ID). ) may be included. That is, the ML-GW 620 may bind the 5G link to the existing 4G bearer by checking the ID of the UE and the 4G bearer ID included in the message.

In step 659 , the NG-MME 615 may transmit an initial context setup request to the 5G-NB 610 , and the 5G-NB 605 receiving it may transmit an Attach Accept to the terminal 600 in step 661 . . The 5G-NB 610 may transmit an initial context setup response to the NG-MME 615 in step 663 , and the terminal 600 may transmit an Attach Complete to the NG-MME 615 in step 665 . Thereafter, the NG-MME 615 may perform bearer modification with the ML-GW 620 in step 667 . The NG-MME 615 may send and receive Modify Bearer request and response messages with the ML-GW 620 , and the messages may include information indicating that the ML-Service has been aggregated.

7A to 7C are diagrams illustrating examples of NAS message extension for ML-capability delivery of a terminal.

In the Attach Request, the ML-capability information of the UE can be delivered to the NG-MME by extending the existing NAS message.

7A shows a part of the Attach Request message content of the existing NAS message. Here, the information element 700 indicating UE network capability consists of three fields as shown in FIG. 7B . A part of the MS network capability value field 705 of FIG. 7B is shown in FIG. 7C. In this case, the ML-capability item of the UE may be added by using the last spare bits 710 of FIG. 7C . For example, instead of spare bits, ML-capability may be expressed as follows.

<ML/1>

0: Mobile station does not support Multilink functionality

1: Mobile station supports Multilink functionality

8A is a flowchart illustrating a multi-link data transmission method of an electronic device operating as a transmitter according to an embodiment of the present invention. As described above, the electronic device may include a terminal as well as a core device.

In step 800, the electronic device may acquire multi-link control information. The MLAP layer of the terminal and the core device may exchange multilink control information to efficiently select a path.

The multilink control information may include radio state information and path characteristic information. The radio state information may include link-failure, link-availability, and signal strength of a radio link, and the path characteristic information may include available bandwidth and delay information of each link.

The radio state information can be collected by the link state analyzer of the terminal MLAP and delivered to the MLAP layer of the core device, which quickly informs the MLAP layer of the core device of the change in the state of the radio link, so that if necessary, the packet transmission path can be quickly transferred to another path. in order to be able to change it.

On the other hand, the path characteristic information is collected by monitoring each link in the path characteristic estimation unit of the MLAP at the receiving end, and the information is transmitted to the transmitting end so that the MLAP at the transmitting end selects a transmission path for each packet or flow in a direction that maximizes the transmission effect. it is for

Meanwhile, the multi-link control information may further include at least one of policy information, subscriber information, flow information, Internet service provider (ISP) information, and service type information.

Various methods of obtaining the multilink control information will be described in detail below.

In step 805, the electronic device may distribute data traffic to each link based on the acquired multi-link control information. Various embodiments of distributing the data traffic will be described below.

In step 810, the electronic device may transmit the distributed data traffic to each link.

8B is a flowchart illustrating a method for receiving multi-link data by an electronic device according to an embodiment of the present invention.

In step 820, the electronic device may acquire multi-link control information. This is the same as previously described with reference to FIG. 8A.

In step 825, the electronic device may receive data traffic through each link based on the acquired multi-link control information.

In step 830, the electronic device may reorder the received traffic using an MLAP sequence number.

9A is a diagram illustrating an example of control information exchange between MLAP layers according to an embodiment of the present invention.

9A shows an example of control information exchange using only in-band signaling. In this method, radio state information and path characteristic information collected by the terminal 900 are exchanged with the ML-GW 915 only through in-band signaling between the MLAP layers 905 and 920 of the transmitting and receiving ends. For example, the path characteristic information may use the control message format (Type 1) of FIG. 9B, and the radio state information collected by the terminal may use the control message format (Type 2) of FIG. 9C.

The meaning of each field in FIG. 9B is as follows.

D/C (1 bit): data or control

Type (2 bits): 3GPP or Non-3GPP feedback, etc.

LN (3 bits): Number of links

BW (16 bits): bandwidth (in Mbps)

The meaning of each field in FIG. 9C is as follows.

D/C (1 bit): data or control

Type (2 bits): 3GPP or Non-3GPP

LN (3 bits): number of links

LID (8 bits): Link ID

A or F: (newly detected) link-availability or (newly detected) link-failure

10A is a diagram illustrating another example of control information exchange between MLAP layers according to an embodiment of the present invention.

10A shows an example of control information exchange using only (2) NAS messages. The MLAP 1005 of the terminal 1000 transmits the collected radio state information and path characteristic information to the NG-MME 1010 using only the NAS message, and the NG-MME 1010 transmits this information to the ML-GW 1015 ) shows an example of control information exchange delivered to the MLAP 1020.

For this method, it is necessary to extend the existing NAS message. First, as shown in FIG. 10B , multilink management 1030 is added by using a reserved field to an existing protocol discriminator value.

10c is a view showing a definition (1035) of a message type for the newly defined multilink management, and may include, for example, two message types: Link status change and Path characteristic feedback. Here, the Link status change message may be for transmitting radio state information, and the Path characteristic feedback message may be for transmitting path characteristic information.

The configuration of the information element of the link status change may be, for example, as shown in FIG. 10D. 10E shows an example of a value of a Link status change information element. Fields LID(1) to LID(k) are IDs of links newly classified as available or failure. For example, LS(1) to LS(k) may represent 0000 if available and 0001 if failure, so that the state of the newly changed link may be transmitted.

The configuration of the information element of the path characteristic feedback may be, for example, as shown in FIG. 10f. 10g shows an example of the value of the Path characteristic feedback information element. Fields LID(1) to LID(n) indicate the ID of each link, and BW(1) to BW(n) may record bandwidth information of each corresponding link.

11 is a diagram illustrating another example of control information exchange between MLAP layers according to an embodiment of the present invention.

11 shows an example of control information exchange using both a NAS message and an in-band message. The MLAP 1105 of the terminal 1100 transmits the collected radio state information to the MLAP 1120 of the ML-GW 1115 through the NG-MME 1110 using the NAS message (ML-S1), and the path The characteristic information is transmitted to the MLAP 1120 using an in-band message (ML-S2). For example, the ML-S1 NAS message may use the Link status change information element value shown in FIG. 10E , and the ML-S2 in-band message may use the Type 1 control message format of FIG. 9B .

12B is a diagram schematically illustrating the configuration of an electronic device supporting multi-link according to an embodiment of the present invention. As described above, the electronic device may include a terminal and a core device.

The electronic device may include a transceiver 1200 and at least one processor 1205 .

The transceiver 1200 may transmit/receive a signal to/from an external device wirelessly and/or by wire under the control of the at least one processor 1205 .

The at least one processor 1205 may perform an operation for multi-link data transmission/reception according to various embodiments of the present disclosure. The at least one processor 1205 may perform the multi-link connection operation described with reference to FIGS. 5 and 6 or the multi-link data transmission/reception operation described with reference to FIGS. 8A and 8B . In this case, at least one processor 1205 may include an MLAP processing unit 1210 for performing the multi-link data transmission/reception operation.

12B is a diagram illustrating components of a multilink adaptation layer in a multilink support system according to an embodiment of the present invention. 12B is a diagram schematically illustrating a logical configuration of an MLAP layer included in the MLAP processing unit 1210 of FIG. 12A .

According to various embodiments of the present disclosure, the MLAP layer includes a link status analysis unit 1220 for analyzing a radio state of a link and a path characteristic estimation unit 1225 for estimating characteristics of each path. ), and may include a path management unit (Path Management) 1230 for managing the link state and path characteristics for each path. The Signaling Control 1235 of the MLAP layer may play a role of sharing multilink control information between the terminal and the corresponding MLAP layer of the core device. The MLAP layer may also include a path control unit 1240 that selects a path for each packet or flow based on the state information for each path provided from the path management unit 1230, and transmits data packets and control signals. and a packet processing unit 1245 for MLAP layer processing upon reception and a packet reordering unit 1250 for managing the ordering of received data packets.

Hereinafter, detailed operations of the path characteristic estimator performed by the MLCP layer at the receiving end and path selection for each packet and path selection for each flow performed by the MLCP layer at the transmitting end according to an embodiment of the present invention will be described in detail.

One of the important factors in path characteristic information is available bandwidth information. This is because the available bandwidth information is used to determine which path and how much is appropriate to distribute packets to each path. As an example, in an embodiment of the present invention, instead of directly estimating the available bandwidth of a radio link, the reception speed of a packet arriving at the receiving end may be measured and the value may be used instead of the available bandwidth value.

The packet reception rate can be calculated as follows.

The packet reception rate measured at time tk is calculated as follows.

Here, n is the number of packets received in the interval [tk-1, tk], and sj is the size of the j-th packet.

The packet reception rate measured at time k is calculated as follows.

Here, 0 ≤ a < 1 is an adjustable parameter, for example, 1/8 may be used.

Meanwhile, another important information among the path characteristics is delay information. Delay information for each path can be used for packet distribution to reduce packet reordering, and can also be used for packet distribution according to specific policies and QoS requirements.

13A shows an example of a method of measuring unidirectional delay for each link. First, the MLAP of the transmitting end (eg, the ML-GW 1305) may record the transmission time ts in the option field of the MLAP header or tail and transmit it. Then, the MLAP of the receiving end (eg, the terminal 1300) can calculate the one-way delay time d by subtracting the transmission time ts from the packet reception time tr.

In the case of a TCP-based application packet, unidirectional delay may be estimated by using the TCP time stamp option as shown in FIG. 13B. When the App server 1310 records and transmits the transmission time ts in the TCP time stamp, the ML-GW 1305 may deliver it to the terminal 1300 . The MLAP of the terminal 1300 may calculate a one-way delay time d(dx + dy) by subtracting the transmission time ts from the packet reception time tr. In this case, although the estimated one-way delay time is different from the actual one-way delay between the ML-GW 1305 and the terminal 1300, the delay between the App server 1310 and the ML-GW 1305 is the terminal 1300 ) and the ML-GW 1305 may be used when it is not relatively large compared to the delay.

14A is a diagram illustrating path selection for each flow as an example of a traffic distribution method of a multilink support system according to an embodiment of the present invention, and FIG. 14B is a diagram illustrating traffic of a multilink support system according to an embodiment of the present invention. As another example of the distribution method, it is a diagram showing path selection for each packet.

Path selection for each flow is to select a specific flow to be transmitted through a specific path according to operator policy, subscriber information, flow information, and/or service type. To this end, the MLAP of the core device obtains various other information that can be used for path selection, such as policy information, subscriber information, ISP information, and/or service type information, through interworking with other core nodes such as PCRF, HSS, and ANDSF. may be

Path selection per flow does not transmit packets of one flow to different paths at the same time. On the other hand, in path selection for each packet, packets belonging to one flow are dynamically split by using a plurality of paths. The main purpose of this method of packet distribution is to increase throughput by using multiple links. Here, the important thing is to minimize the distribution algorithm that determines how many packets to send to which link and out-of-packets received from a plurality of links.

For path selection for each packet, various distribution algorithms such as Weighted Round-Robin (WRR), which distributes packets to a specific path by a fraction of a specific weight, can be used. Although a detailed algorithm is not described herein, a generic packet distribution method based on available bandwidth is described as an example. If there are two paths P1 and P2, and the available bandwidths of each path are A1 and A2, then the algorithm operation is as follows.

- Estimate A1 and A2, the respective available bandwidth of path P1 and P2

- Compute following expected values

- Upon arrival of each packet

Sends packets over path P1 with probability

Sends packets over path P2 with probability

A generic algorithm based on bandwidth and delay can be described as follows.

- Estimate A1 and A2, the respective available bandwidth of path P1 and P2

- Compute following expected values

- Estimate RTT or one-way delay D1 and D2 of each path

- Compute the following

- Upon arrival of each packet

Sends packets over path P1 with probability

Sends packets over path P2 with probability

In addition, when the difference in path characteristics between a plurality of links is out of a predetermined range, it is possible to select the best path to transmit the packet, otherwise it is possible to distribute the packet according to the two distribution methods mentioned above.

15 is a flowchart illustrating a method of reordering received data in a multilink support system according to an embodiment of the present invention.

The MLAP layer at the receiving end re-orders the packets coming through multiple paths using the MLAP sequence number. The receiving end waits for packet reception in step 1500 , and checks whether a reordering timer expires in step 1505 . For example, if N=3, when the timer expires for the third time in a row, all packets in the reordering buffer are released to the upper layer as shown in step 1525, otherwise the timer is reset as shown in step 1515 Each time it expires, k preset packets can be released to the upper layer. Here, k may be any changeable value, for example, may be set to 1.

When a new packet arrives before the reordering timer expires in step 1505, the MLAP sequence is aligned with the packet received in step 1520, and in step 1525, the rearrangement is completed, i.e., the ordered packet is delivered to the upper layer. You can restart the rearrangement timer.

Each of the above-described components of the electronic device according to various embodiments of the present disclosure may be composed of one or more components, and the name of the corresponding component may vary depending on the type of the electronic device. An electronic device according to various embodiments of the present disclosure may be configured to include at least one of the above-described components, and some components may be omitted or may further include additional other components. In addition, since some of the components of the electronic device according to various embodiments of the present disclosure are combined to form a single entity, the functions of the components prior to being combined may be performed identically.

The terms “~ unit”, “device” or “module” used in various embodiments of the present invention refer to, for example, a unit including one or a combination of two or more of hardware, software, or firmware. can mean The terms “unit”, “device” or “module” are used interchangeably with terms such as, for example, unit, logic, logical block, component or circuit ( can be used interchangeably). A “part”, “device” or “module” may be a minimum unit of an integrally formed component or a part thereof. A “unit”, “device” or “module” may be a minimum unit or a part of performing one or more functions. A “part”, “device” or “module” may be implemented mechanically or electronically. For example, "~ unit", "device" or "module" according to various embodiments of the present invention is known or to be developed in the future, an ASIC (application-specific integrated circuit) chip, an FPGAs (field field) that performs certain operations. - It may include at least one of programmable gate arrays and programmable-logic devices.

Embodiments of the present disclosure disclosed in the present specification and drawings are merely provided for specific examples to easily explain the technical content of the present disclosure and help the understanding of the present disclosure, and are not intended to limit the scope of the present disclosure. Therefore, the scope of the present disclosure should be construed as including all changes or modifications derived from the technical spirit of the present disclosure in addition to the embodiments disclosed herein as being included in the scope of the present disclosure.

Claims (14)

In a communication method of a transmission device using a multi-link in a wireless communication system,
obtaining multilink control information from a multilink adaptation protocol (MLAP) layer of a receiving device by an MLAP layer of the transmitting device;
determining whether a difference in characteristic values between a plurality of multilinks is greater than a threshold value;
When the difference in the characteristic value is not greater than the threshold value, determining, by the MLAP layer of the transmission device, transmission data distribution to the plurality of multilinks based on the multilink control information - the plurality of multilink is associated with a plurality of radio access technology (RAT) types;
simultaneously transmitting the distributed transmission data through the plurality of multi-links; and
selecting one path from the plurality of multilinks when the difference between the characteristic values is greater than the threshold value; and
transmitting data through the selected path; A communication method comprising a.
The method of claim 1,
The multi-link control information includes radio state information and path characteristic information of each link,
The radio state information of each link includes information related to at least one of signal strength, link-availability, and link-failure,
The path characteristic information of each link comprises information related to at least one of an available bandwidth and a path delay.
3. The method of claim 2,
The multi-link control information further comprises at least one of policy information, subscriber information, flow information, Internet service provider (ISP) information, and service type information.
3. The method of claim 2,
The determining step is
and determining distribution of the transmission data in units of data flows based on the multi-link control information.
The method of claim 1,
The determining step is
and determining distribution of the transmission data in units of data packets based on the multi-link control information.
The method of claim 1,
receiving data simultaneously or selectively through each link based on the multi-link control information; and
reordering the received data; Communication method, characterized in that it further comprises.
The method of claim 1,
The multilink control information is a communication method, characterized in that it is obtained using at least one of in-band signaling and NAS (Non-Access Stratum) signaling.
In an electronic device including a multilink adaptation protocol (MLAP) layer in a wireless communication system supporting multilink, the electronic device comprising:
a transceiver for transmitting and receiving a signal; and
Obtaining multilink control information from the MLAP layer of the receiving device, checking whether a difference in a characteristic value between a plurality of multilinks is greater than a threshold value, and if the difference in the characteristic value is not greater than the threshold value, the The MLAP layer of the electronic device determines transmission data distribution to the plurality of multilinks based on the multilink control information, wherein the plurality of multilinks includes a plurality of radio access technology (RAT) types and related, controlling the transceiver to transmit the distributed transmission data to the plurality of multilinks simultaneously, and when the difference in the characteristic value is greater than the threshold value, select one path from the plurality of multilinks; at least one processor controlling data to be transmitted through the selected path; An electronic device comprising a.
9. The method of claim 8,
The multi-link control information includes radio state information and path characteristic information of each link,
The radio state information of each link includes information related to at least one of signal strength, link-availability, and link-failure,
The electronic device according to claim 1, wherein the path characteristic information of each link includes information related to at least one of an available bandwidth and a path delay.
10. The method of claim 9,
The multi-link control information further includes at least one of policy information, subscriber information, flow information, Internet service provider (ISP) information, and service type information.
9. The method of claim 8,
the at least one processor,
and determining distribution of the transmission data in units of data flows based on the multi-link control information.
9. The method of claim 8,
the at least one processor,
and determining distribution of the transmission data in units of data packets based on the multi-link control information.
9. The method of claim 8,
The at least one processor,
and controlling to receive data simultaneously or selectively through each link based on the multi-link control information, and reordering the received data.
9. The method of claim 8,
The multilink control information is obtained by using at least one of in-band signaling and NAS (Non-Access Stratum) signaling.

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