KR102322380B1 - Methods for processing Uplink user data of relay node and Apparatuses thereof - Google Patents

Abstract

The present disclosure relates to an IAB (Integrated Access and Backhaul)-based data processing method and apparatus utilizing 5G NR wireless communication technology. An embodiment provides a method for a relay node to process uplink user data, the step of receiving uplink user data from a terminal and a terminal bearer identifier ( UE-bearer-ID), selecting a backhaul RLC channel to transmit uplink user data based on at least one of a terminal bearer identifier and donor base station address information, and receiving uplink user data through the selected backhaul RLC channel It provides a method and apparatus comprising the step of transmitting to a donor base station or another relay node.

Description

A method for processing uplink user data in a relay node and an apparatus therefor

The present disclosure relates to an IAB (Integrated Access and Backhaul)-based data processing method and apparatus utilizing 5G NR wireless communication technology.

In a wireless communication system, the relay technology is used for the purpose of extending cell coverage by using additional network nodes.

Therefore, the relay technology to which the conventional LTE technology is applied supports data transfer at the IP packet level of the relay node, and only one relay node is configured to transfer the IP packet between the terminal and the base station.

That is, the relay technology to which the conventional LTE technology is applied provides only a single-hop relay function to provide a simple service, and most configurations are directed and configured through static operations, administration and management (OAM). Accordingly, a multi-hop relay could not be configured.

In addition, in the case of supporting multi-hop relay through the conventional LTE technology, data could not be separately processed through a plurality of relay nodes, and there is a problem in that signaling and data processing above the IP layer may increase delay.

In order to solve this problem, research on a technology for accurately delivering user data to a base station by configuring a multi-hop is required.

In the background described above, an embodiment of the present disclosure proposes a relay structure for transmitting uplink user data of a terminal to a donor base station through a backhaul RLC channel when a plurality of relay hops are configured.

In addition, an embodiment intends to propose a method of processing an RRC message for relaying an RRC message through one or more hops while maintaining security between a terminal and a base station in a multi-hop relay structure.

An embodiment devised in the above-mentioned problem is a method for a relay node to process uplink user data, the step of receiving uplink user data from a terminal and logical channel identification information associated with the RLC PDU of the uplink user data deriving a terminal bearer identifier (UE-bearer-ID) using It provides a method comprising transmitting uplink user data to a donor base station or another relay node through the

In addition, in an embodiment, in a relay node for processing uplink user data, a terminal bearer identifier ( UE-bearer-ID), a control unit that selects a backhaul RLC channel for transmitting uplink user data based on at least one of a terminal bearer identifier and donor base station address information, and a donor of uplink user data through the selected backhaul RLC channel It provides a relay node including a transmitter for transmitting to a base station or another relay node.

The present disclosure dynamically configures a plurality of relay hops to provide an effect of effectively classifying and processing data according to requirements for each terminal or service.

In addition, the present disclosure provides an effect of preventing the delay of signaling and data processing above the IP layer while maintaining the security of the RRC message transmitted in the relay structure.

1 is a diagram schematically illustrating a structure of an NR wireless communication system to which this embodiment can be applied.
2 is a diagram for explaining a frame structure in an NR system to which this embodiment can be applied.
3 is a diagram for explaining a resource grid supported by a radio access technology to which this embodiment can be applied.
4 is a diagram for explaining a bandwidth part supported by a radio access technology to which the present embodiment can be applied.
5 is a diagram exemplarily illustrating a synchronization signal block in a radio access technology to which the present embodiment can be applied.
6 is a diagram for explaining a random access procedure in a radio access technology to which the present embodiment can be applied.
7 is a diagram illustrating an example of a relay-based user plane protocol structure in LTE technology.
8(A) and 8(B) are diagrams illustrating a relay node startup (RN startup) procedure in LTE technology.
9 is a diagram for explaining an RRC connection establishment procedure using a relay node according to an embodiment.
10 is a flowchart illustrating an operation in which a relay node transmits an RRC message according to an embodiment.
11 is a diagram exemplarily illustrating a protocol structure through which an RRC message is transmitted according to an embodiment.
12 is a signal diagram illustrating a procedure for transmitting an RRC message to a base station according to an embodiment.
13 is a flowchart illustrating an operation in which a relay node transmits uplink user data according to an embodiment.
14 is a diagram exemplarily illustrating a protocol structure through which uplink user data is transmitted according to an embodiment.
15 is a diagram exemplarily illustrating a protocol structure through which uplink user data is transmitted in a donor base station having a single structure according to an embodiment.
16 is a diagram exemplarily illustrating a protocol structure through which uplink user data is transmitted according to an embodiment.
17 is a diagram exemplarily illustrating a protocol structure through which uplink user data is transmitted according to an embodiment.
18 is a diagram exemplarily illustrating a protocol structure through which uplink user data is transmitted according to an embodiment.
19 is a diagram exemplarily illustrating a protocol structure through which uplink user data is transmitted according to an embodiment.
20 is a block diagram illustrating a configuration of a relay node according to an embodiment.

Hereinafter, some embodiments of the present technical idea will be described in detail with reference to exemplary drawings. In adding reference numerals to components of each drawing, the same components may have the same reference numerals as much as possible even though they are indicated in different drawings. In addition, in describing the present technical idea, if it is determined that a detailed description of a related known configuration or function may obscure the gist of the present technical idea, the detailed description may be omitted.

In addition, in describing the components of the present embodiments, terms such as first, second, A, B, (a), (b), etc. may be used. These terms are only for distinguishing the elements from other elements, and the essence, order, order, or number of the elements are not limited by the terms. When it is described that a component is “connected”, “coupled” or “connected” to another component, the component may be directly connected or connected to the other component, but other components may be interposed between each component. It will be understood that each component may be “interposed” or “connected”, “coupled” or “connected” through another component.

In addition, terms and technical names used in this specification are for describing specific embodiments, and technical ideas are not limited to the terms. The terms described below may be interpreted as meanings generally understood by those of ordinary skill in the technical field to which the present technical idea belongs, unless otherwise defined. When the term is an incorrect technical term that does not accurately express the present technical idea, it should be understood by being replaced with a technical term that can be correctly understood by those skilled in the art. In addition, the general terms used in this specification should be interpreted according to the definition in the dictionary or according to the context before and after, and should not be interpreted in an excessively reduced meaning.

A wireless communication system in the present specification refers to a system for providing various communication services such as voice and data packets using radio resources, and may include a terminal, a base station, and a core network.

The embodiments disclosed below may be applied to a wireless communication system using various wireless access technologies. For example, the present embodiments are CDMA (code division multiple access), FDMA (frequency division multiple access), TDMA (time division multiple access), OFDMA (orthogonal frequency division multiple access), SC-FDMA (single carrier frequency division multiple access) It can be applied to various wireless access technologies, such as CDMA may be implemented with a radio technology such as universal terrestrial radio access (UTRA) or CDMA2000. TDMA may be implemented with a radio technology such as global system for mobile communications (GSM)/general packet radio service (GPRS)/enhanced datarates for GSM evolution (EDGE). OFDMA may be implemented with a wireless technology such as Institute of Electrical and Electronics Engineers (IEEE) 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802-20, and evolved UTRA (E-UTRA). IEEE 802.16m is an evolution of IEEE 802.16e, and provides backward compatibility with a system based on IEEE 802.16e. UTRA is part of the universal mobile telecommunications system (UMTS). 3rd generation partnership project (3GPP) long term evolution (LTE) is a part of evolved UMTS (E-UMTS) that uses evolved-UMTSterrestrial radio access (E-UTRA), and employs OFDMA in the downlink and SC- in the uplink. FDMA is employed. As such, the present embodiments may be applied to currently disclosed or commercialized radio access technologies, or may be applied to radio access technologies currently under development or to be developed in the future.

On the other hand, in the present specification, a terminal is a generic concept meaning a device including a wireless communication module that performs communication with a base station in a wireless communication system, and is a UE in WCDMA, LTE, HSPA, and IMT-2020 (5G or New Radio). (User Equipment), of course, should be interpreted as a concept including all of MS (Mobile Station), UT (User Terminal), SS (Subscriber Station), wireless device, etc. in GSM. In addition, the terminal may be a user portable device, such as a smart phone, depending on the type of use, and in the V2X communication system may mean a vehicle, a device including a wireless communication module in the vehicle, and the like. In addition, in the case of a machine type communication system, it may mean an MTC terminal, an M2M terminal, etc. equipped with a communication module to perform machine type communication.

A base station or cell in the present specification refers to an end that communicates with a terminal in terms of a network, a Node-B (Node-B), an evolved Node-B (eNB), gNode-B (gNB), a Low Power Node (LPN), Sector, site, various types of antennas, base transceiver system (BTS), access point, point (eg, transmission point, reception point, transmission/reception point), relay node (Relay Node) ), mega cell, macro cell, micro cell, pico cell, femto cell, RRH (Remote Radio Head), RU (Radio Unit), and small cell (small cell), etc.

In the various cells listed above, since there is a base station controlling each cell, the base station can be interpreted in two meanings. 1) in relation to the radio area, it may be the device itself providing a mega cell, a macro cell, a micro cell, a pico cell, a femto cell, or a small cell, or 2) may indicate the radio area itself. In 1), the devices providing a predetermined radio area are controlled by the same entity, or all devices interacting to form a radio area cooperatively are directed to the base station. A point, a transmission/reception point, a transmission point, a reception point, etc. become an embodiment of a base station according to a configuration method of a wireless area. In 2), the radio area itself in which the signal is received or transmitted from the viewpoint of the user terminal or the neighboring base station may be indicated to the base station.

In the present specification, a cell is a component carrier having a coverage of a signal transmitted from a transmission/reception point or a coverage of a signal transmitted from a transmission/reception point, and the transmission/reception point itself. can

Uplink (Uplink, UL, or uplink) refers to a method of transmitting and receiving data by the terminal to and from the base station, and downlink (Downlink, DL, or downlink) refers to a method of transmitting and receiving data to and from the terminal by the base station do. A downlink may mean a communication or communication path from a multi-transmission/reception point to a terminal, and an uplink may mean a communication or communication path from the terminal to a multi-transmission/reception point. In this case, in the downlink, the transmitter may be a part of multiple transmission/reception points, and the receiver may be a part of the terminal. Also, in the uplink, the transmitter may be a part of the terminal, and the receiver may be a part of the multi-transmission/reception point.

The uplink and downlink transmit and receive control information through a control channel such as a Physical Downlink Control CHannel (PDCCH), a Physical Uplink Control CHannel (PUCCH), etc., and a Physical Downlink Shared CHannel (PDSCH), a Physical Uplink Shared CHannel (PUSCH), etc. Data is transmitted and received by configuring the same data channel. Hereinafter, a situation in which signals are transmitted and received through channels such as PUCCH, PUSCH, PDCCH and PDSCH may be expressed in the form of 'transmitting and receiving PUCCH, PUSCH, PDCCH and PDSCH'. do.

For clarity of explanation, the present technical idea is mainly described below for a 3GPP LTE/LTE-A/NR (New RAT) communication system, but the present technical features are not limited thereto.

After research on 4G (4th-Generation) communication technology, 3GPP is conducting research on 5G (5th-Generation) communication technology to meet the requirements of ITU-R's next-generation wireless access technology. Specifically, 3GPP is conducting research on LTE-A pro, which improved LTE-Advanced technology to meet the requirements of ITU-R as a 5G communication technology, and new NR communication technology separate from 4G communication technology. LTE-A pro and NR are both expected to be submitted as 5G communication technology, but hereinafter, for convenience of description, the present embodiments will be described focusing on NR.

In the NR operation scenario, various operation scenarios were defined by adding consideration of satellites, automobiles, and new verticals to the existing 4G LTE scenarios. It is deployed in a range and supports the mMTC (Massive Machine Communication) scenario that requires a low data rate and asynchronous connection, and the URLLC (Ultra Reliability and Low Latency) scenario that requires high responsiveness and reliability and supports high-speed mobility. .

To satisfy this scenario, NR discloses a wireless communication system to which a new waveform and frame structure technology, low latency technology, mmWave support technology, and forward compatible technology are applied. In particular, the NR system presents various technical changes in terms of flexibility to provide forward compatibility. The main technical features will be described with reference to the drawings below.

<Normal NR system>

1 is a diagram schematically illustrating a structure of an NR system to which this embodiment can be applied.

1, the NR system is divided into a 5G Core Network (5GC) and an NR-RAN part, and the NG-RAN controls the user plane (SDAP/PDCP/RLC/MAC/PHY) and UE (User Equipment) It consists of gNBs and ng-eNBs that provide planar (RRC) protocol termination. The gNB interconnects or gNBs and ng-eNBs are interconnected via an Xn interface. gNB and ng-eNB are each connected to 5GC through the NG interface. 5GC may be configured to include an Access and Mobility Management Function (AMF) in charge of a control plane such as terminal access and mobility control functions, and a User Plane Function (UPF) in charge of a control function for user data. NR includes support for both frequency bands below 6 GHz (FR1, Frequency Range 1) and frequency bands above 6 GHz (FR2, Frequency Range 2).

gNB means a base station that provides NR user plane and control plane protocol termination to a terminal, and ng-eNB means a base station that provides E-UTRA user plane and control plane protocol termination to a terminal. The base station described in this specification should be understood as encompassing gNB and ng-eNB, and may be used as a meaning to refer to gNB or ng-eNB separately if necessary.

<NR Waveform, Pneumologic and Frame Structure>

In NR, a CP-OFDM waveform using a cyclic prefix is used for downlink transmission, and CP-OFDM or DFT-s-OFDM is used for uplink transmission. OFDM technology is easy to combine with MIMO (Multiple Input Multiple Output), and has advantages of using a low-complexity receiver with high frequency efficiency.

Meanwhile, in NR, since the requirements for data rate, delay rate, coverage, etc. are different for each of the three scenarios described above, it is necessary to efficiently satisfy the requirements for each scenario through the frequency band constituting an arbitrary NR system. . To this end, a technique for efficiently multiplexing a plurality of different numerology-based radio resources has been proposed.

값이 2의 지수 값으로 사용되어 지수적으로 변경된다.Specifically, the NR transmission numerology is determined based on sub-carrier spacing and cyclic prefix (CP), and is based on 15 kHz as shown in Table 1 below.

The value is used as an exponent value of 2 to change exponentially.

subcarrier spacing Cyclic prefix Supported for data Supported for synch 0 15 Normal Yes Yes One 30 Normal Yes Yes 2 60 Normal, Extended Yes No 3 120 Normal Yes Yes 4 240 Normal No Yes

As shown in Table 1 above, the NR pneumatology can be divided into five types according to the subcarrier spacing. This is different from that the subcarrier interval of LTE, one of the 4G communication technologies, is fixed at 15 kHz. Specifically, subcarrier intervals used for data transmission in NR are 15, 30, 60, and 120 kHz, and subcarrier intervals used for synchronization signal transmission are 15, 30, 12, 240 kHz. In addition, the extended CP is applied only to the 60khz subcarrier interval. On the other hand, as for the frame structure in NR, a frame having a length of 10 ms is defined, which is composed of 10 subframes having the same length of 1 ms. One frame can be divided into half frames of 5 ms, and each half frame includes 5 subframes. In the case of a 15 kHz subcarrier interval, one subframe consists of one slot, and each slot consists of 14 OFDM symbols. 2 is a diagram for explaining a frame structure in an NR system to which this embodiment can be applied.

Referring to FIG. 2 , a slot is fixedly composed of 14 OFDM symbols in the case of a normal CP, but the length of the slot may vary according to a subcarrier interval. For example, in the case of a numerology having a 15 kHz subcarrier interval, the slot is 1 ms in length and is composed of the same length as the subframe. On the other hand, in the case of numerology having a 30 kHz subcarrier interval, a slot consists of 14 OFDM symbols, but two slots may be included in one subframe with a length of 0.5 ms. That is, the subframe and the frame are defined to have a fixed time length, and the slot is defined by the number of symbols, so that the time length may vary according to the subcarrier interval.

On the other hand, NR defines a basic unit of scheduling as a slot, and also introduces a mini-slot (or a sub-slot or a non-slot based schedule) to reduce transmission delay in a radio section. When a wide subcarrier interval is used, the length of one slot is shortened in inverse proportion, so that transmission delay in a radio section can be reduced. The mini-slot (or sub-slot) is for efficient support of the URLLC scenario and can be scheduled in units of 2, 4, or 7 symbols.

Also, unlike LTE, NR defines uplink and downlink resource allocation at a symbol level within one slot. In order to reduce HARQ delay, a slot structure capable of transmitting HARQ ACK/NACK directly within a transmission slot is defined, and this slot structure is named as a self-contained structure and will be described.

NR is designed to support a total of 256 slot formats, of which 62 slot formats are used in Rel-15. In addition, a common frame structure constituting an FDD or TDD frame is supported through a combination of various slots. For example, a slot structure in which all symbols of a slot are set to downlink, a slot structure in which all symbols are set to uplink, and a slot structure in which downlink symbols and uplink symbols are combined are supported. In addition, NR supports that data transmission is scheduled to be distributed in one or more slots. Accordingly, the base station may inform the terminal whether the slot is a downlink slot, an uplink slot, or a flexible slot using a slot format indicator (SFI). The base station may indicate the slot format by indicating the index of the table configured through UE-specific RRC signaling using SFI, and may indicate dynamically through DCI (Downlink Control Information) or statically or semi-statically through RRC. may be

<NR Physical Resources>

In relation to a physical resource in NR, an antenna port, a resource grid, a resource element, a resource block, a bandwidth part, etc. are considered can be

An antenna port is defined such that a channel on which a symbol on an antenna port is carried can be inferred from a channel on which another symbol on the same antenna port is carried. When the large-scale property of a channel carrying a symbol on one antenna port can be inferred from a channel carrying a symbol on another antenna port, the two antenna ports are QC/QCL (quasi co-located or QC/QCL) quasi co-location). Here, the wide range characteristic includes one or more of delay spread, Doppler spread, frequency shift, average received power, and received timing.

3 is a diagram for explaining a resource grid supported by a radio access technology to which this embodiment can be applied.

Referring to FIG. 3 , in the resource grid, since NR supports a plurality of numerologies on the same carrier, a resource grid may exist according to each numerology. In addition, the resource grid may exist according to an antenna port, a subcarrier interval, and a transmission direction.

A resource block consists of 12 subcarriers, and is defined only in the frequency domain. In addition, a resource element is composed of one OFDM symbol and one subcarrier. Accordingly, as in FIG. 3 , the size of one resource block may vary according to the subcarrier interval. In addition, NR defines "Point A" serving as a common reference point for a resource block grid, a common resource block, a virtual resource block, and the like.

4 is a diagram for explaining a bandwidth part supported by a radio access technology to which the present embodiment can be applied.

In NR, unlike LTE in which the carrier bandwidth is fixed at 20Mhz, the maximum carrier bandwidth is set from 50Mhz to 400Mhz for each subcarrier interval. Therefore, it is not assumed that all terminals use all of these carrier bandwidths. Accordingly, in NR, as shown in FIG. 4 , a bandwidth part may be designated within the carrier bandwidth and used by the terminal. In addition, the bandwidth part is associated with one numerology and is composed of a subset of continuous common resource blocks, and may be dynamically activated according to time. A maximum of four bandwidth parts are configured in the terminal, respectively, in uplink and downlink, and data is transmitted/received using the activated bandwidth part at a given time.

In the case of a paired spectrum, the uplink and downlink bandwidth parts are set independently, and in the case of an unpaired spectrum, to prevent unnecessary frequency re-tunning between downlink and uplink operations For this purpose, the downlink and uplink bandwidth parts are set in pairs to share a center frequency.

<NR Initial Connection>

In NR, the terminal accesses the base station and performs a cell search and random access procedure in order to perform communication.

Cell search is a procedure in which the UE synchronizes the cell of the corresponding base station using a synchronization signal block (SSB) transmitted by the base station, obtains a physical layer cell ID, and obtains system information.

5 is a diagram exemplarily illustrating a synchronization signal block in a radio access technology to which the present embodiment can be applied.

Referring to FIG. 5, the SSB consists of a primary synchronization signal (PSS) and a secondary synchronization signal (SSS) occupying 1 symbol and 127 subcarriers, respectively, and a PBCH spanning 3 OFDM symbols and 240 subcarriers.

The UE receives the SSB by monitoring the SSB in the time and frequency domains.

SSB can be transmitted up to 64 times in 5ms. A plurality of SSBs are transmitted using different transmission beams within 5 ms, and the UE performs detection on the assumption that SSBs are transmitted every 20 ms when viewed based on one specific beam used for transmission. The number of beams that can be used for SSB transmission within 5 ms time may increase as the frequency band increases. For example, up to 4 SSB beams can be transmitted in 3 GHz or less, and SSB can be transmitted using up to 8 different beams in a frequency band of 3 to 6 GHz and up to 64 different beams in a frequency band of 6 GHz or more.

Two SSBs are included in one slot, and the start symbol and the number of repetitions within the slot are determined according to the subcarrier interval as follows.

On the other hand, the SSB is not transmitted at the center frequency of the carrier bandwidth, unlike the SS of the conventional LTE. That is, the SSB may be transmitted in a place other than the center of the system band, and a plurality of SSBs may be transmitted in the frequency domain when wideband operation is supported. Accordingly, the UE monitors the SSB using a synchronization raster, which is a candidate frequency location for monitoring the SSB. The carrier raster and synchronization raster, which are the center frequency location information of the channel for initial access, are newly defined in NR, and the synchronization raster has a wider frequency interval than the carrier raster, so that the terminal can support fast SSB search. can

The UE may acquire the MIB through the PBCH of the SSB. MIB (Master Information Block) includes minimum information for the terminal to receive the remaining system information (RMSI, Remaining Minimum System Information) broadcast by the network. In addition, the PBCH includes information on the position of the first DM-RS symbol in the time domain, information for the UE to monitor SIB1 (eg, SIB1 neurology information, information related to SIB1 CORESET, search space information, PDCCH related parameter information, etc.), offset information between the common resource block and the SSB (the position of the absolute SSB in the carrier is transmitted through SIB1), and the like. Here, the SIB1 neurology information is equally applied to messages 2 and 4 of the random access procedure for accessing the base station after the UE completes the cell search procedure.

The aforementioned RMSI means SIB1 (System Information Block 1), and SIB1 is broadcast periodically (ex, 160 ms) in the cell. SIB1 includes information necessary for the UE to perform an initial random access procedure, and is periodically transmitted through the PDSCH. In order for the UE to receive SIB1, it must receive neurology information used for SIB1 transmission and CORESET (Control Resource Set) information used for scheduling SIB1 through the PBCH. The UE checks scheduling information for SIB1 by using SI-RNTI in CORESET, and acquires SIB1 on PDSCH according to the scheduling information. SIBs other than SIB1 may be transmitted periodically or may be transmitted according to the request of the terminal.

6 is a diagram for explaining a random access procedure in a radio access technology to which the present embodiment can be applied.

Referring to FIG. 6 , upon completion of cell search, the terminal transmits a random access preamble for random access to the base station. The random access preamble is transmitted through the PRACH. Specifically, the random access preamble is transmitted to the base station through a PRACH consisting of continuous radio resources in a specific slot that is periodically repeated. In general, when a UE initially accesses a cell, a contention-based random access procedure is performed, and when performing random access for beam failure recovery (BFR), a contention-free random access procedure is performed.

The terminal receives a random access response to the transmitted random access preamble. The random access response may include a random access preamble identifier (ID), a UL grant (uplink radio resource), a temporary C-RNTI (Temporary Cell - Radio Network Temporary Identifier), and a Time Alignment Command (TAC). Since one random access response may include random access response information for one or more terminals, the random access preamble identifier may be included to inform which terminal the included UL Grant, temporary C-RNTI, and TAC are valid. The random access preamble identifier may be an identifier for the random access preamble received by the base station. The TAC may be included as information for the UE to adjust uplink synchronization. The random access response may be indicated by a random access identifier on the PDCCH, that is, RA-RNTI (Random Access - Radio Network Temporary Identifier).

Upon receiving the valid random access response, the terminal processes information included in the random access response and performs scheduled transmission to the base station. For example, the UE applies the TAC and stores the temporary C-RNTI. In addition, data stored in the buffer of the terminal or newly generated data is transmitted to the base station by using the UL grant. In this case, information for identifying the terminal should be included.

Finally, the terminal receives a downlink message for contention resolution.

In the present specification, frequencies, frames, subframes, resources, resource blocks, regions, bands, subbands, control channels, data channels, synchronization signals, various reference signals, various signals, and various messages related to NR (New Radio) in the present specification can be interpreted in various meanings used in the past or present or used in the future.

LTE relay technology

In LTE technology, the relay technology was used for the purpose of extending cell coverage through the use of an additional network node called a relay node (RN). LTE RN relayed user plane data and control plane data at the IP packet level. In addition, a service was provided only through one RN between a donor eNB (DeNB), which is a base station serving a relay node, and the UE. That is, only relay through a single hop was supported between the UE and the DeNB.

7 is a diagram illustrating an example of a relay-based user plane protocol structure in LTE technology.

Referring to FIG. 7 , the terminal 700 communicates with the donor base station 720 through the relay node 710 . The donor base station 720 transmits the data of the terminal 700 to the gateway 730 . The terminal 700 includes L1 physical layer and L2 layer, IP, TCP/UDP, App. composed of layers. The relay node 710 is connected to the terminal 700 through the L1 and L2 layers, and is connected to the donor base station 720 through the GTP-u layer above the IP layer to transmit and receive data. To this end, the relay protocol in LTE technology is configured as shown in FIG. 7 .

8 is a diagram illustrating a relay node startup (RN startup) procedure in LTE technology.

In the LTE relay technology, the RN startup procedure of FIGS. 8 (A) and 8 (B) for starting the RN operation is used to configure the parameters required for the RN.

8(A) and 8(B), after the RN 800 turns on the power (S805), the RN 800 performs a two-step start procedure. When the RN 800 is powered on, it has two steps because the RN 800 does not know which cell is allowed for network attach. Since not all base stations support RN 800 to serve RN 800 , RN 800 needs to identify which cells support RN 800 operation. If the RN 800 already knows accessible cells, phase I may be omitted and phase II may be immediately performed.

Hereinafter, Phase I will be described with reference to FIG. 8(A).

Phase I: Attach for RN preconfiguration.

The RN 800 accesses the E-UTRAN/EPC as a terminal upon power-up (S815), and searches for initial configuration parameters including a list of DeNB cells from the RN OAM 850 (S825). After the operation S825 is completed, the RN 800 separates from the network as a terminal (S835), and triggers Phase II described below. The MME 820 selects the S-GW and the P-GW 830 for the RN 800 as a general terminal. (The RN attaches to the E-UTRAN/EPC as a UE at power-up and retrieves initial configuration parameters, including the list of DeNB cells, from RN OAM. After this operation is complete, the RN detaches from the network as a UE and triggers Phase II. The MME performs the S-GW and P-GW selection for the RN as a normal UE.)

Hereinafter, Phase II will be described with reference to FIG. 8(B).

Phase II: Attach for RN operation.

Referring to FIG. 8B , the RN 800 connects to the DeNB 810 selected from the list collected in Phase I to start the relay operation (S806).

When the DeNB 810 starts to establish a bearer for S1/X2, the RN 800 starts to establish an S1 and X2 connection with the DeNB 810. In addition, the DeNB 810 initiates the RN reconfiguration procedure through RRC signaling for the RN specific parameter (S807). (The RN connects to a DeNB selected from the list acquired duringPhase I to start relay operations. After the DeNB initiates setup of bearer for S1/X2, the RN initiates the setup of S1 and X2 associations with the DeNB. In addition, the DeNB may initiate an RN reconfiguration procedure via RRC signaling for RN-specific parameters.)

After performing the S1 setup with the RN 800 (S808), the DeNB 810 performs an S1 eNB configuration update procedure when the configuration data is updated through the RN connection (S809). In addition, after performing X2 setup with the RN 800 ( S811 ), the DeNB 810 updates cell information by performing an X2 eNB configuration update procedure ( S812 ). (After the S1 setup, the DeNB performs the S1 eNB Configuration Update procedure(s), if the configuration data for the DeNB is updated dueto the RN attach. After the X2 setup, the DeNB performs the X2 eNB Configuration Update procedure(s) to update the cell information). In Phase II, ECGIs of RN cells are configured by RN OAM (In this phase the RN cells' ECGIs are configured by RN OAM).

When the Phase II phase is completed, the RN 800 starts to operate as a relay (S813).

As described above, since the RN of the conventional LTE relay technology only supported single-hop relay, most of the configuration for the relay was provided through a static OAM. From the viewpoint of the terminal, the RN acts as a base station, and the RN recognizes the donor base station as a core network entity and configures the terminal context in the RN. Therefore, most of the configuration of the RN is indicated and configured through static OAM, and only a specific radio configuration (eg, RN subframe configuration) for the entire RN device was configured and instructed by the decision of the donor base station. Accordingly, when multi-hop is supported between the terminal and the base station (donor base station), it is difficult to efficiently configure according to the service requirements for each terminal. If it is intended to support multi-hop relay through the conventional LTE technology, there is also a problem in that there is no method of processing data by dividing the data through a plurality of relay nodes. In addition, signaling and data processing above the IP layer have a problem that may increase delay.

High layer functional split structure

The next-generation radio access network (hereinafter, referred to as NR, 5G, or NG-RAN for convenience of description) is distributed with a centralized node (hereinafter, referred to as CU (Central Unit) for convenience of description) to support efficient network construction. It may be provided separately as a node (hereinafter, referred to as a DU (Distributed Unit) for convenience). That is, the base station may be configured by being divided into CUs and DUs in logical or physical terms. A base station in the present disclosure is a base station to which NR technology is applied and may be denoted as gNB in order to distinguish it from an LTE base station (eNB). In addition, NR technology may be applied to the base station, the donor base station, and the relay node unless otherwise described below.

CU refers to a logical node hosting RRC, SDAP, and PDCP protocols. Alternatively, CU means a logical node hosting RRC and higher layer L2 protocol (PDCP). A CU controls the operation of one or more DUs. The CU terminates the F1 interface associated with the DU. (gNB Central Unit (gNB-CU): a logical node hosting RRC, SDAP and PDCP protocols, and controls the operation of one or more gNB-DUs. The gNB-CU also terminates F1 interface connected with the gNB-DU.)

DU refers to a logical node hosting the RLC, MAC, and PHY layers. The operation of the DU is partially controlled by the CU. One DU supports one or a plurality of cells. One cell is supported by only one DU. The DU terminates the F1 interface associated with the CU (gNB Distributed Unit (gNB-DU): a logical node hosting RLC, MAC and PHY layers, and its operation is partly controlled by gNB-CU. One gNB-DU supportsone or multiplecells .One cell is supportedby only one gNB-DU.The gNB-DU terminates F1 interface connected with the gNB-CU.)

(The NG-RAN consists of a set of gNBs connected to the 5GC through the NG.)

Base stations may be interconnected through the Xn interface. (gNBs can be interconnected through the Xn.) A base station may consist of one CU and DUs. (A gNB may consist of a gNB-CU and gNB-DUs) . (A gNB-CU and a gNB-DU is connected via F1 logical interface.) One DU is connected to only one CU. (One gNB-DU is connected to only one gNB-CU). (For NG-RAN, the NG and Xn-C interfaces for a gNB consisting of a gNB-CU and gNB- DUs, terminate in the gNB-CU.)

As described above, the F1 interface is an interface that provides interconnection between a CU and a DU, and the F1 Application Protocol (F1AP) is used to provide a signaling procedure on the corresponding interface.

For EN-DC, the S1-U interface and X2-C interface for one base station composed of CU and DU are terminated at the CU. (For EN-DC, the S1-U and X2-C interfaces for a gNB consisting of a gNB-CU and gNB-DUs, terminate in the gNB-CU.) other gNBs and the 5GC as a gNB).

New Radio (NR) based relay

3GPP is working on initial specifications for 5G wireless communication technology (NR) to satisfy various requirements according to technological development. In NR, which can use a high frequency band, the use of relay technology may increase due to the use of a higher bandwidth and a multi-beam system compared to LTE. This allows operators to more easily build a dense network of self-backhauled NR cells that provide their own backhaul function. However, the millimeter wave band may suffer from severe short-term blocking. In addition, small coverage of millimeter wave band and beam operation may require connection to a base station connected to a wire/fiber through a multi-hop relay. In this case, it was impossible to connect the terminal to the base station connected to the wired/optical line using the relay technology according to the conventional LTE technology. In particular, multi-hop relay may be difficult to use for delay-sensitive 5G service transmission as data needs to be processed in multi-hop. Accordingly, it is necessary to study various protocol structures to satisfy the quality of each service in multi-hop, but a specific technique for this is not presented.

Accordingly, the present disclosure intends to propose an NR relay structure capable of effectively classifying data according to quality requirements for each terminal or service by configuring a plurality of hop relays. In addition, it is intended to propose a specific procedure and apparatus for a terminal to connect to a base station through a multi-hop relay node under the NR relay structure.

The embodiments disclosed below may be practiced individually or in combination of some or all of each. In addition, for convenience of understanding, a case in which NR access to an NR terminal is relayed to an NR base station (donor base station) through NR-based wireless self-backhauling will be described below for convenience of understanding. However, this is only an example for description, and each of the embodiments described below may be applied to a case of relaying LTE access to an LTE terminal to an LTE base station (donor base station) through NR-based wireless self-backhauling.

A donor base station in the present specification means a radio network node (or base station or gNB or part of gNB) that terminates an interface (NG interface, for example, N2, N3 interface) to the core network. The donor base station may be physically connected to the core network or another base station through a wired/optical line. In addition, the donor base station may configure a backhaul with other NR nodes such as base stations, CUs, DUs, and core network nodes (AMF, UPF, etc.) using NR radio technology. The donor base station may consist of one CU and one or more DUs, similarly to the NR base station. The donor base station may be replaced by various terms such as IAB-DN, DgNB, DN, and Donor base station.

Meanwhile, an integrated access and backhaul (IAB) node refers to a node that supports access to a terminal and wireless self-backhauling using NR radio technology. An IAB node may configure a backhaul to another NR node using NR radio technology. Also, the IAB node cannot be physically connected to other NR nodes through wired/optical lines. The IAB node may be replaced by various terms such as relay node, NR-RN, NR relay, and integration node. Hereinafter, it will be described as a relay node or an IAB node.

In addition, the Un interface represents an interface between an IAB node and an IAB node or an interface between an IAB node and a donor base station. The Un interface may be replaced by various terms such as IAB backhaul interface, U-IAB interface, and Ui interface.

When a terminal wants to access a donor base station through a multi-hop IAB node, the IAB nodes must be able to effectively classify user data traffic between the terminal and the donor base station and process/deliver it. For example, the IAB node should be able to determine a next hop and transmit the uplink data to the next hop so that the uplink data belonging to a specific radio bearer received from a specific terminal can be classified and delivered to the donor base station. For another example, the IAB node determines a next hop so that downlink data belonging to a specific radio bearer of a specific UE received from a specific donor base station can be classified and processed/delivered to the corresponding UE, and the corresponding downlink data is delivered to the next hop. should be able

In order to implement this operation, the multi-hop IAB node and the donor base station must perform RRC connection establishment. That is, similar to the RN startup procedure described in FIG. 8 , the IAB node may perform a procedure for configuring parameters necessary for the IAB node in order to start the IAB node operation.

9 is a diagram for explaining an RRC connection establishment procedure using a relay node according to an embodiment.

The procedure described with reference to FIG. 9 may be applied in various protocol structures described below. In FIG. 9, for convenience of explanation, a case in which the terminal and the donor base station transmit and receive data through two hops (eg, IAB 1, IAB 2) will be mainly described. This is only for convenience of description, and may be equally applied to a case including an arbitrary number of IAB nodes.

Referring to FIG. 9 , a donor base station 903 performs a connection setup operation with IAB nodes IAB 2 and 902 that are directly connected through a wireless interface ( S910 ). When the connection setup operation is completed, the donor base station 903 performs a connection setup operation with other IAB nodes IAB 1 and 901 (S915).

The terminal 900 transmits a random access preamble to IAB 1 901 and initiates a random access operation to IAB 1 901 (S920). IAB 1 901 transmits a response to the random access preamble to the terminal 900 in a random access response message (S925). The terminal 900 transmits an RRC connection request message to initiate an RRC connection establishment procedure with the donor base station 903 (S930). The donor base station 903 is the terminal 900 or IAB 1 901 or IAB 2 902 on the backhaul interface between the IAB 2 902 and the donor base station 903 through the IAB 2 902 and the RRC connection reconfiguration procedure. Configures a signaling radio bearer for transmitting a control message of (S935). In addition, the donor base station 903 is the IAB 1 901 and the RRC connection reconfiguration procedure through the IAB 1 901 and the donor base station 903 interface on the terminal 900 or the IAB 1 901 for the control message transmission. A signaling radio bearer is configured (S940).

The donor base station 903 sets up an RRC connection to the terminal 900 by transmitting an RRC connection setup message to the terminal 900 (S945). The terminal 900 sets up an RRC connection with the donor base station 903 using the received RRC connection setup message, and sends the RRC connection setup complete message to the donor base station through IAB 1 901 and/or IAB 2 902. It transmits to (903) (S950).

When the RRC connection setup with the terminal 900 is completed, the donor base station 903 performs signaling with the core network entity (S955). Through this, the PDU session ID to be configured in the terminal 900, S-NSSAI, QoS flow indicator (QFI), and QoS profile information associated with the QFI are received from the core network entity. Thereafter, the donor base station 903 performs a radio resource configuration procedure for distinguishing and relaying data radio bearers for IAB 1 901 and IAB 2 902 and the terminal 900 (S965, S970). The donor base station 903 configures radio resources in the terminal 900 by transmitting an RRC connection reconfiguration message (S970). The terminal 900 notifies confirmation of radio resource configuration by transmitting an RRC connection reconfiguration complete message (S975).

As described above, through the relay node (IAB node), the terminal and the donor base station establish an RRC connection and configure a radio resource (radio bearer).

Hereinafter, each step described with reference to FIG. 9 will be described in more detail by dividing it by step.

1) Connection setup of the IAB node (IAB 2) directly connected to the donor base station through the wireless interface

If the IAB node is directly connected to the donor base station through a wireless interface, the IAB node may establish an RRC connection to the donor base station to perform network registration. For example, if the IAB node selects a cell provided by the donor base station and is connected to the donor base station through the corresponding cell, the IAB node may establish an RRC connection to the donor base station to perform network registration. The IAB node may extract initial configuration parameters including the donor base station cell list from the (IAB) OAM for preconfiguration of the IAB node. Afterwards, for the IAB operation, the IAB node may select a cell having the best radio quality from among the cells included in the donor base station cell list, establish an RRC connection through the corresponding cell, and perform the IAB node operation.

As an example, the IAB node and cells of the IAB node may be configured by IAB OAM. The cell configuration of the IAB node and the IAB node may be performed together when the initial configuration parameters including the donor base station cell list are extracted from the IAB OAM, or may be performed during the phase II process of network registration as an IAB node thereafter. Alternatively, it may be pre-configured in the IAB node.

As another example, the radio resource configuration for the IAB node and the cells of the IAB node may be configured as directed by the donor base station. The radio resource configuration operation may be performed in phase I in which the IAB node performs network registration as a terminal. Alternatively, the radio resource configuration operation may be performed in phase II of performing network registration as an IAB node. Alternatively, the radio resource configuration operation may be performed and configured when triggered by the donor base station. If the NR-based IAB node supports the multi-hop topology, the donor base station may control the radio resources of the IAB node for efficient radio resource control. Through this, when the terminal accesses the donor base station and transmits and receives data, the IAB nodes can effectively classify user data traffic between the terminal and the donor base station according to QoS parameters and process/deliver them.

As another example, the IAB node transmits an interface setup request message between the IAB node and the donor base station to the donor base station. For convenience of description, the interface between the IAB node and the donor base station is hereinafter referred to as an F3 interface. This is for convenience of description and may be replaced with any other name. The F3 interface may represent an interface between an access IAB node (e.g. first hop IAB node) serving the terminal and a donor base station. If the donor base station is separated into a CU and a DU, the F3 interface may indicate an interface between an access IAB node serving the terminal and the donor base station DU, or an interface between an access IAB node serving the terminal and the donor base station CU.

Similar to the F1 Application Protocol (F1AP) of the F1 interface, which is an interface between the CU and the DU, an upper layer protocol for providing a signaling procedure between the donor base station and the IAB node on the F3 interface may be provided, and for convenience of explanation, this is referred to as the F3AP (F3 Application Protocol) is used. For example, the above-described interface setup request message between the IAB node and the donor base station indicates an F3AP message used for exchanging application-level data required for the IAB node and the donor base station to operate properly on the F3 interface.

The F3 interface setup request message includes a list of cells configured in the IAB node. Alternatively, the F3 interface setup request message may include a list of cells configured in the IAB node and ready to be activated or a list of candidate cells that can be configured/activated. The F3 interface setup request message may be included in the uplink RRC message and transmitted. For example, the uplink RRC message may be an RRC setup complete message or a UL Information Transfer message or a UE assistant Information message.

The donor base station guarantees connectivity to the core network. For this reason, the donor base station may perform NG setup or gNB Configuration update procedure with 5GC (5G Core network).

The donor base station transmits an F3 interface setup response message between the IAB node and the donor base station to the IAB node. The F3 interface setup response message may include a list of cells to be configured in the IAB node. Alternatively, the F3 interface setup response message may include a cell list to be activated among the cell list to be activated in the IAB node or the candidate cell list. The F3 interface setup response message may be included in the downlink RRC message and transmitted. For example, the downlink RRC message may be an RRC connection reconfiguration message or a DL Information Transfer message. If the IAB node succeeds in activating the cell, the activated cell becomes operational (the cells become operational).

2) Connection setup of an IAB node (IAB 1) connected through a wireless interface provided by another IAB node (ex, IAB 2)

If the IAB node is connected to the donor base station through another IAB node, the IAB node may establish an RRC connection to the donor base station through the other IAB node and perform network registration. For example, if an IAB node selects a (activated) cell provided by another IAB node and connects to a donor base station through another IAB node, the IAB node establishes an RRC connection to the donor base station through the other IAB node and registers the network. can be performed.

For example, for preconfiguration of an IAB node connected to a donor base station through another IAB node, the IAB node may extract an initial configuration parameter including a cell list of another IAB node in addition to the donor base station cell list from the IAB OAM. Alternatively, the IAB node may extract an initial configuration parameter including a cell list of another IAB node except for the donor base station cell list from the IAB OAM. Alternatively, the IAB node is a donor base station cell list from the IAB OAM, a cell list of another IAB node, an activated cell list of another IAB node, a cell list of an adjacent IAB node, an activated cell list of an adjacent IAB node, a cell of a neighboring IAB node An initial configuration parameter including at least one of a list, a neighbor cell list, and a neighbor cell list associated with the IAB node may be extracted.

Thereafter, for the IAB operation, the IAB node may select a cell having the best radio quality from among the cells included in the received cell list, establish an RRC connection through the corresponding cell, and perform the IAB node operation.

As another example, the donor base station may indicate/configure pre-configuration information or configuration information of the IAB node connected to the donor base station through another IAB node to the IAB node through the RRC message. For example, the pre-configuration information or configuration information may include a donor base station cell list, a cell list of another IAB node, an activated cell list of another IAB node, a cell list of an adjacent IAB node, an activated cell list of an adjacent IAB node, a neighboring IAB It may include information on at least one of a cell list of a node, a list of neighboring cells, and a list of neighboring cells associated with the IAB node. The aforementioned RRC message may be included in the RRC connection release message or the RRC connection reconfiguration message. The donor base station may release the RRC connection of the IAB node. Thereafter, for the IAB operation, the IAB node (or terminal) may select a cell having the best radio quality from among the cells included in the received cell list, establish an RRC connection through the corresponding cell, and perform the IAB node operation.

If the IAB node performs the same cell selection/reselection operation as the IDLE mode general terminal, there is a possibility of selecting/reselecting the cell with the best radio quality or selecting/reselecting the cell with the best radio quality on the priority frequency. high. However, in order to efficiently perform the relay operation, it may be desirable to consider whether the selected/reselected cell is a cell provided by the donor base station or the number of hops to the donor base station.

As an example for this, in selecting/reselecting a cell included in the received cell list, the IAB node may select/reselect in consideration of whether each cell provides a donor base station or the number of hops to the donor base station. Specifically, when the IAB node performs an operation for cell selection/reselection, information for indicating whether a corresponding cell is a cell provided by a donor base station in a cell selection criterion (or a cell reselection criterion/cell ranking criterion) or a donor At least one of an adjustment parameter/offset/scaling value according to the number of hops to the base station may be considered (added or subtracted). A parameter additionally applied to the above-described cell selection criterion may be applied and used to one of the following cell selection/cell reselection criterion parameters.

The following formula shows an example of a cell selection reference value.

Srxlev = Q _rxlevmeas - (Q _rxlevmin + Q _{rxlevminoffset} ) - Pcompensation - Qoffset _temp

Squal = Q _qualmeas - (Q _qualmin + Q _{qualminoffset} ) - Qoffset _temp

Each parameter means a value in the table below, and Qoffset _temp means an offset parameter that can be applied as needed. A parameter additionally applied according to the present disclosure may be subtracted or added to each of the above-described equations.

On the other hand, the above-described donor base station cell list, cell list of another IAB node, parameters for cell selection / cell reselection of the IAB node (eg, information for indicating whether the cell is provided by the donor base station, up to the donor base station Information for indicating the number of connection hops, additional parameters) and one or more of the initial configuration parameters of the IAB node may be broadcast through system information of a cell provided by a donor base station or a cell provided by an IAB node.

Or, the above-mentioned donor base station cell list, cell list of another IAB node, parameters for cell selection / cell reselection of the IAB node (eg, information for indicating whether the cell is provided by the donor base station, up to the donor base station) Information for indicating the number of connection hops, additional parameters) and one or more of the initial configuration parameters of the IAB node may be provided through additional system information/On demand system information.

Specifically, in NR, it is divided into minimum system information that is broadcast at a fixed period and can always be received by the terminal, and other system information (RMSI) that is not minimum system information. Minimum system information is broadcast at a fixed period and includes basic information necessary for initial access. can On the other hand, other system information (RMSI) provides the period and scheduling information broadcast by the system information block type 1 (SystemInformationBlockType1). The information of the donor base station provided for the IAB node may not be essential minimum system information. Accordingly, the terminal may acquire other system information (RMSI) in an on-demand method based on the minimum system information. For example, other system information may be received in the process of performing random access. For another example, other system information may be received in the RRC connection establishment process.

Or, the aforementioned donor base station cell list, cell list of another IAB node, parameters for cell selection/cell reselection of the IAB node (eg, information for indicating whether a cell is provided by the donor base station, up to the donor base station) Information for indicating the number of connection hops, additional parameters) and one or more of the initial configuration parameters of the IAB node may be transmitted by the donor base station to the IAB node through a dedicated RRC message. For example, the dedicated RRC message transmitted by the base station may be an RRC connection release message or an RRC connection reconfiguration message.

Or, the above-mentioned donor base station cell list, cell list of another IAB node, parameters for cell selection / cell reselection of the IAB node (eg, information for indicating whether the cell is provided by the donor base station, up to the donor base station) Information for indicating the number of connection hops, additional parameters) and one or more of the initial configuration parameters of the IAB node may be transmitted by the donor base station to the IAB node through the F3AP message.

In addition, the above-described donor base station cell list, cell list of other IAB nodes, and parameters for cell selection/cell reselection of the IAB node are determined when the IAB node experiences radio link failure (eg, the IAB node in the connected state is the upper IAB node), the IAB node can be used to perform cell selection/reselection/link selection for connection recovery to the donor base station. For example, if the IAB node detects a radio link failure, the IAB node re-establishes the connection to the donor base station through another cell. This procedure may be provided through a normal cell selection procedure, or cell selection may be performed among cells provided through an alternate path pre-configured by the donor base station. When an arbitrary IAB node detects a radio link failure through an RRC-only message, the donor base station may configure the IAB node with information to prioritize reconfiguration to support fast recovery. The information includes at least one of a priority cell, a priority cell list, a priority frequency, a reset candidate cell, a reset candidate cell list, a donor base station cell list, a cell list of another IAB node, and the number of connection hops to the donor base station for each cell. may include When the IAB node detects a radio link failure to the donor base station or upper IAB node, it re-establishes a connection to the donor base station using the corresponding information. For example, the IAB node may preferentially perform cell selection among the indicated cells. As another example, the IAB node may select the indicated cell by checking the physical cell identifier of each cell through broadcast system information. When the radio link of the IAB node is reset, the number of connection hops to the donor base station of another IAB node connected to the IAB node is changed. The donor base station transmits information for modifying the number of connection hops to the donor base station of each IAB node or the cell accommodated by each IAB node, and the corresponding IAB node receives it, changes and stores the information. Corresponding information may be indicated from the donor base station to the IAB node through an RRC message or an F3AP message.

On the other hand, the terminal also prioritizes the cell based on parameters such as information for indicating whether the cell is provided by the donor base station and information for indicating the number of connection hops to the donor base station. Cell selection/cell reselection may be performed. have.

3) Random access preamble transmission

When the IDLE state terminal selects a cell associated with the IAB 1 node according to the cell selection/cell reselection criteria, when the corresponding terminal attempts network access (eg, triggering outgoing data transmission from the IDLE terminal), the terminal is IAB 1 node to start the random access procedure. The MAC entity of the terminal transmits a random access preamble to the IAB 1 node. That is, the terminal recognizes the IAB 1 node as the base station and transmits the random access preamble.

4) Random access response

The UE transmitting the contention-based random access preamble starts a random access response window at the start of the first PDCCH occurrence after a specific symbol duration fixed from the end of the preamble transmission. While the random access response window is operating, the UE monitors the PDCCH for the random access response identified by the RA-RNTI. When the UE receives the random access response message identified by the RA-RNTI in the PDCCH monitoring process, the UE performs the rest of the random access procedure using the corresponding response message.

5) Send RRC connection request message

The UE transmits an RRC connection request message to IAB 1 node.

The IAB 1 node transmits an RRC connection request message to the donor base station through the IAB 2 node.

As an example, the IAB 1 node may transmit an RRC connection request message in an uplink RRC message. As another example, the IAB 1 node may transmit an RRC connection request message through a signaling radio bearer (eg, a signaling radio bearer configured for SRB0 or SRB1/SRB2 configured for any signaling radio bearer). The RRC connection request message may be included in the F3AP message transmitted by the IAB 1 node to the donor base station through the F3 interface and transmitted through the signaling radio bearer. The F3AP message for this may be an application level message for transmitting an uplink RRC message. As another example, the F3AP message transmitted by the IAB 1 node to the donor base station through the F3 interface may include information about one or more of a terminal identifier and a signaling bearer type (eg SRB0, SRB 1, SRB2) in addition to the RRC connection request message. . For example, a message transmitted by the IAB 1 node to the donor base station may include a C-RNTI. Alternatively, the terminal identifier is a valid C-RNTI transmitted by the terminal to the IAB 1 node, an RA-RNTI included when the terminal transmits a random access preamble for contention-based random access, and a Temporary C allocated by IAB 1 through a random access response message. -RNTI and IAB 1 may be one or more of the RA-RNTI information and the C-RNTI of the UE confirmed through the random access response message. Through this, the donor base station acquires the C-RNTI allocated by the access IAB node of the terminal, and uniquely identifies the terminal together with IAB node information and/or cell identification information to control radio resources. As another example, the terminal identifier may be an I-RNTI allocated by the IAB1 node. The I-RNTI is identification information for identifying an inactive state terminal and may uniquely identify a terminal context of the corresponding terminal. As another example, the IAB node 1 may transmit a new terminal identifier (IAB-RNTI for convenience of description) capable of uniquely identifying the terminal accepted by the donor base station to the donor base station. The donor base station can uniquely identify the terminal through the IAB-RNTI and IAB node information. For another example, the message transmitted by the IAB 1 node to the donor base station may include the IAB UE F3AP ID for uniquely identifying the UE association through the F3 interface.

In the contention-based random access, since the UE selects the random access preamble by itself, there is a possibility that one or more UEs simultaneously transmit the same random access preamble. In this case, confirmation by the base station that has received the random access preamble may not be sufficient, and an additional contention resolution step is required. To this end, the IAB node or the donor base station may indicate to the terminal which terminal transmission is actually received.

When the terminal transmits the MAC PDU through the uplink radio resource allocated by the random access response, the terminal includes the identification information of the terminal in the MAC PDU. If the UE has a valid C-RNTI, the C-RNTI MAC CE is included in the MAC PDU. For example, message 3 (MSG3) contains a C-RNTI. IAB 1 node may include a C-RNTI when transmitting an RRC connection request message to a donor base station in order to support centralized control of radio resources of connected IAB nodes. If the UE does not have a valid C-RNTI, for example, when a CCCH message (RRC connection request message) is transmitted, a CCCH SDU including identification information of the UE is included in the MAC PDU.

After that, when the UE detects the C-RNTI through the PDCCH or if the UE receives the same UE contention resolution identity MAC CE as the CCCH SDU transmitted previously, the UE considers that the random access procedure is successful.

As an example for this, the IAB node 1 stores/buffers/stores/maintains the RRC connection request message (CCCH SDU) until it receives the RRC connection setup message from the donor base station.

As another example for this, the IAB node 1 may receive an RRC connection request message (CCCH SDU) together when receiving the RRC connection setup message from the donor base station.

As another example for this, the donor base station stores the C-RNTI of the terminal as a temporary C-RNTI as the terminal context. Thereafter, upon receiving the RRC connection setup complete message from the terminal, the value of the temporary C-RNTI is set to the C-RNTI.

As another example for this, the IAB 1 node stores/buffers/stores/maintains the C-RNTI received from the terminal. After receiving the RRC connection setup message from the donor base station, the value of the temporary C-RNTI is set to the C-RNTI. Alternatively, upon receiving the RRC connection setup complete message from the terminal, the value of the temporary C-RNTI is set to the C-RNTI.

6~7) Signaling radio bearer configuration for transmitting the control message of the corresponding terminal or IAB node to the IAB 1 node / IAB 2 node

The donor base station configures SRB1 for the terminal that has transmitted the RRC connection request message to the IAB 1 node/IAB 2 node, and may transmit data (RRC message) through the corresponding signaling radio bearer between the donor base station and the terminal.

To this end, the donor base station may configure the configuration information required in the IAB1 node/IAB2 node in the IAB1 node/IAB2 node. For example, the configuration information may include mapping information for mapping data for each signaling radio bearer of each terminal to a radio bearer/RLC bearer between interfaces and transmitting the data.

For example, the donor base station configures SRB1 between the IAB 1 node and the donor base station to transmit the RRC message of the terminal and the F3AP message of the IAB 1 node to the IAB 1 node, which is the access IAB node of the terminal, and the RRC message of the terminal through the corresponding signaling radio bearer. and the F3AP message of the IAB 1 node may be transmitted to the donor base station. As another example, the donor base station configures SRB1 between the IAB 2 node and the donor base station to transmit the RRC message of the IAB 1 node and the F3AP message of the IAB 2 node to the IAB 2 node, which is the access IAB node of the IAB 1 node. The RRC message of the IAB 1 node and the F3AP message of the IAB2 node may be transmitted to the donor base station. As another example, the donor base station maps the RRC message of the corresponding terminal to the IAB 1 node, which is the access IAB node of the terminal, to SRB1 between the IAB 1 node and the donor base station and transmits the RRC message or F3AP message including mapping information to the corresponding signaling radio bearer can be transmitted via As another example, the donor base station is the access IAB node of the IAB 1 node, the IAB 2 node, the incoming RLC channel including the RRC message of the terminal received from the IAB 1 node, and the outgoing RLC channel transmitted to the donor base station RRC including mapping information message or F3AP message. Through this, the RRC message of each terminal may be separately transmitted between the IAB 1 node and the IAB 2 node, and between the IAB 2 node and the donor base station.

If necessary, steps 6 to 7 may be performed simultaneously with step 8 or after step 8.

8) Transmission of RRC connection setup message from donor base station to terminal

The donor base station transmits the RRC connection setup message to the terminal through the IAB2 node and the IAB1 node. The RRC connection setup message transmitted by the donor base station to the terminal may be transmitted to the IAB 1 node or the IAB 2 node through the SRB. The RRC connection setup message may be included in the F3AP control message between the donor base station and the IAB 1 node and transmitted to the IAB 1 node through the SRB.

9) The terminal transmits the RRC connection setup complete message to the donor base station through the IAB node 1

If the CCCH SDU is included in MSG3 and the PDCCH transmission is addressed by the temporary C-RNTI of the UE, if the MAC PDU is successfully decoded, if the UE contention resolution identity in the MAC CE matches the CCCH SDU transmitted to MSG3, the UE considers the competition resolution to be successful. The UE sets the value of the temporary C-RNTI to C-RNTI.

The terminal transmits an RRC connection setup complete message to the donor base station through the IAB node1. The RRC connection setup complete message may be transmitted from the IAB node 1 to the IAB node 2 or the donor base station through the SRB. In this case, the RRC connection setup completion message may be included in the F3AP message and transmitted through the SRB.

On the other hand, if the terminal identifier is used as C-RNTI (16 bits), the probability of collision occurrence is very low. Therefore, as an example of the aforementioned terminal identifier, the C-RNTI allocated by the IAB-1 node may be used. However, there is also a possibility that overlapping/collision/contention C-RNTIs are used in cells provided by a plurality of IAB nodes accommodated in the donor base station. In order to prevent collision, a node identifier may be used in addition to the terminal identifier allocated by the C-RNTI or IAB 1 node as the terminal identifier. The corresponding node identifier may be assigned when the IAB node establishes/attempts to access the donor node. The node identifier may be assigned to the IAB node in the donor base station through the RRC message.

When a terminal wants to access a donor base station through a multi-hop IAB node, the IAB nodes must be able to effectively classify user data traffic between the terminal and the donor base station and process/deliver it. For example, the IAB node should be able to determine a next hop so that uplink data belonging to a specific radio bearer received from a specific terminal can be delivered to a donor base station, and be able to forward the corresponding data to the next hop.

For another example, the IAB node must be able to determine the next hop and forward the data to the next hop so that the downlink data belonging to a specific radio bearer of a specific terminal received from a specific donor base station can be classified and processed/delivered to the corresponding terminal. do.

10) Core network signaling

When the donor base station completes RRC connection establishment with the terminal, it performs signaling with the core network entity. For example, the donor base station sends an NGAP initial UE message to the core network through the NG interface between the base station and the AMF, receives the initial terminal context setup message, and sets the terminal context. Core network signaling carry out the procedure Through this, the PDU session ID to be configured in the terminal 900, S-NSSAI, QoS flow indicator (QFI), and QoS profile information associated with the QFI are received from the core network entity. One of any signaling messages described in 3GPP TS 38.413 NGAP protocol may be used.

11~12) Configure a data radio bearer for the corresponding terminal in the IAB 1 node/IAB 2 node

When the donor base station configures a data radio bearer (DRB) with the terminal to transmit/receive data, the IAB 1 node/IAB 2 node may configure the necessary configuration information in the IAB 1 node/IAB 2 node. The terminal is a terminal that has transmitted the RRC connection request message, and transmits and receives data to and from the donor base station through the configured DRB.

To this end, the configuration information configured in the IAB 1 node and/or the IAB 2 node may include mapping information for mapping data for each data radio bearer of each terminal to the radio bearer/RLC bearer between interfaces and transmitting the data. For example, mapping information for mapping data for each data radio bearer of each terminal to the interface between the IAB 1 node and the IAB 2 node and the IAB 2 node and the donor base station may include mapping information for transmission. Corresponding information may be indicated to the IAB node through the F3AP message between the donor base station and the IAB node.

Steps 11 to 12 may be performed simultaneously with step 13 or after step 13 .

13~14) Configure radio resources in the terminal through the RRC connection reconfiguration procedure

The donor base station configures radio resources (radio bearer configuration, etc.) in the terminal through the RRC connection reconfiguration message. The terminal sends a confirmation message for this.

As described above, the terminal and the donor base station of the IAB nodes establish a connection through a relay operation and transmit/receive an RRC message.

Hereinafter, the operation of the relay node (IAB node) that transmits the RRC message of the terminal to the donor base station will be described in more detail. For example, the RRC message transmitted by the terminal may be delivered to the donor base station through the signaling radio bearer, and may be delivered by being included in the F3AP message. In this embodiment, the uplink RRC message will be mainly described, but it may also be applied to the downlink RRC message. In addition, the relay node below will be described as an example of the above-described IAB node, but is not limited thereto.

10 is a flowchart illustrating an operation in which a relay node transmits an RRC message according to an embodiment.

Referring to FIG. 10 , in a method of processing an RRC message, the relay node may perform the step of establishing a signaling radio bearer or higher layer connection with a donor base station ( S1000 ). The relay node may establish a connection with the donor base station and may establish a signaling radio bearer. Alternatively, the relay node may establish a higher layer connection with the donor base station. For example, the upper layer connection may mean F3 Application Protocol (F3AP).

For example, the relay node refers to an integrated access and backhaul (IAB) node that is connected to the terminal through radio access and is connected to another relay node or a donor base station through wireless backhaul. Alternatively, the relay node may refer to an IAB node connected to another relay node or a donor base station through wireless backhaul. That is, here, the relay node may be an IAB node that performs direct connection with the terminal through radio access, or an IAB node that is not directly connected to the terminal by being located in the middle of the relay path or on the side of the donor base station.

The relay node may receive mapping information from a donor base station to establish a signaling radio bearer or higher layer connection. For example, the relay node may establish a connection using mapping information between the logical channel identification information of the terminal and the backhaul RLC channel received from the donor base station.

For the signaling radio bearer to be configured, ciphering is performed between the PDCP entity of the relay node and the PDCP entity of the donor base station.

On the other hand, the relay node may perform the step of receiving the RRC message transmitted from the terminal (S1010). For example, the relay node receives the RRC message through radio access with the terminal.

The relay node may perform the step of transmitting the RRC message to the donor base station or another relay node using a signaling radio bearer or a higher layer protocol (S1020). For example, the relay node may transmit the donor base station address information by adding the address information of the donor base station to the F3AP message including the RRC message in the adaptation entity of the relay node. Here, the address information of the donor base station may mean a GPRS Tunneling Protocol (GTP) tunnel endpoint identifier (TEID) received from the donor base station or an IP address of the donor base station.

In addition, the RRC message received from the terminal may be added to the payload of the F3AP message and transmitted through the signaling radio bearer. In addition to this, the F3AP message may further include at least one of terminal identification information and signaling radio bearer identification information.

Through this, the relay node includes the RRC message of the terminal in the payload of the F3AP and transmits it to the donor base station through the signaling radio bearer. In addition, in order to transmit through the signaling radio bearer, the donor base station performs ciphering in the PDCP entity.

11 is a diagram exemplarily illustrating a protocol structure through which an RRC message is transmitted according to an embodiment.

Referring to FIG. 11 , although the donor base station 1130 assumes a separate structure of CU and DU, it can be applied even when the donor base station 1130 does not have a separate structure. That is, there is no limitation on the structure of the donor base station 1130 .

The RRC and PDCP of the terminal 1100 are connected to the RRC and PDCP layers of the donor base station 1130 , and the RLC of the terminal 1100 is associated with the RLC layer of the IAB 2 1110 . The terminal 1100 transmits an RRC message to the incoming RLC entity of the IAB 2 1110 through the RLC entity associated with the SRB between the terminal 1100 and the donor base station 1130 . IAB 2 1110 is linked with the donor base station 1130 through F3-AP, and transfers the RRC message of the terminal 1100 to IAB 1 1120 through the SRB between the IAB 2 1110 and the donor base station 1130. do. IAB 1 (1120) is a backhaul RLC channel between IAB 2 (1110) and IAB 1 (1120) linked to an SRB (MT's SRB in the drawing) for transmitting the RRC message of the terminal is IAB 1 (1120) and the donor base station (1130) It is mapped to an inter-backhaul RLC channel to deliver the RRC message of the terminal 1100 .

If necessary, IAB 2 (1110) and IAB 1 (1120) separate and process the transmitted RRC message including the Adaptation entity. The RRC message may be included in the payload of the F3AP message and delivered through the SRB.

12 is a signal diagram illustrating a procedure for transmitting an RRC message to a base station according to an embodiment. In FIG. 12 , a case in which the MT (Mobile Terminate) part of IAB 2 is connected to the donor base station will be described as an example. Accordingly, IAB 2 is recognized similarly to the terminal from the standpoint of IAB 1, and the above-described RRC message transfer procedure may be applied.

IAB nodes may be divided into an MT part and a DU part, and the MT part is recognized as a function similar to a terminal in terms of a donor base station or a connected IAB node. The DU part is recognized as a function similar to that of the DU base station in terms of the terminal or the connected IAB node. As described above, the DU base station represents a logical node hosting the RLC, MAC, and PHY layers.

Referring to FIG. 12 , IAB 1 ( 1210 ) receives an RRC connection request message from IAB 2 ( 1200 ) ( S1230 ). The IAB 2 (1200) MT part performs normal cell search and cell selection, and transmits an "RRC connection request" to the IAB 1 (1210) DU part. The RRC message is encapsulated as shown in 1231, and payload 1 transmitted to the donor base station includes PDCP and RRC data (IAB-node2 MT part performs normal cell discovery and cell selection and sends "RRC connection request" to IAB-node1 DU part).

IAB 1 (1210) DU part receives payload 1 transmitted from IAB 2 (1200) MT part. Payload 1 indicates a PDCP PDU including an RRC message.

The DU part of IAB 1 1210 generates an F3AP message (ie, an initial UL RRC message) for carrying payload 1 (S1235) (IAB-node1 DU part generates F3AP message (ie the initial UL RRC Message) to carry the RRC message sent from IAB-node2 MT part).

The MT part of the IAB 1 1210 transmits the encapsulated uplink F3AP message to the DU 1221 of the donor base station 1220 through the SRB (S1240) (IAB-node1 MT part transmits the encapsulated uplink F3AP message to Donor- DU via SRB). The uplink F3AP message 1241 additionally includes IAB 2 1200 F3AP UE ID and Adaptation layer information. Payload 2 of 1241 includes PDCP, F3AP, and payload 1.

The DU 1221 of the donor base station 1220 learns a specific message type (the F3AP message of the IAB node). Then it removes the header of the adaptation layer and encapsulates payload 2 (including the F3AP message of the IAB node) in its own F1AP message (S1245) (Donor-DU learns the specific message type (F3AP message of IAB-node). Then it removes the header of adaptation layer, and encapsulates the payload2 (including the F3AP message of IAB-node) in its own F1AP message).

The DU 1221 of the donor base station 1220 transmits the F1AP message 1251 including the F3AP message of the IAB 1 1210 to the CU 1222 of the donor base station 1220 (S1250) (Donor-DU sends its F1AP message which contains the IAB-node1's F3AP message towards the donor-CU).

The CU 1222 of the donor base station 1220 decapsulates the F1AP message 1251 received from the DU 1221 of the donor base station 1220 and then obtains payload 2. The CU 1222 of the donor base station 1220 obtains an "RRC connection request" message in payload 2 through additional decapsulation (S1255) (After decapsulation of the F1AP message received from Donor-DU, Donor-CU get payload2, and obtains the "RRC connection request" message inside payload2 through further decapsulation).

The CU 1222 of the donor base station 1220 sends a F1AP message (eg, DL IAB F1AP) including payload 2 and routing information for payload 2 (eg, IAB 1 address, donor base station CU address, etc.) message transmission) to the DU 1221 of the donor base station 1220 (S1260) (Donor-CU sends the F1AP message (eg DL IAB F1AP message transfer) which contains payload2 towards the Donor-DU and routing information (eg, IAB-node 1 address, Donor-CU address, etc.) for the payload2).

The DU 1221 of the donor base station 1220 extracts payload 2 from the received F1AP message (eg, DL IAB F1AP message), and adds an adaptation layer header including essential routing information for payload 2 (S1265)(Donor-DU extract payload2 from the received F1AP message (eg DL IAB F1AP message transfer), and adds the adaptation layer header which includes essential routing information for payload2).

DU 1221 of donor base station 1220 transmits downlink F3AP message (DL RRC message transmission inside payload 2) encapsulated in IAB 1 1210 MT part via SRB (S1270) (Donor-DU transmits) the encapsulated downlink F3AP message (DL RRC message transfer, inside payload2) towards IAB-node1 MT part via SRB).

The MT part of IAB 1 1210 learns a specific message type (F3AP message of the IAB node) according to a specific SRB or message type indicator, and the F3AP message is the routing information of the adaptation header. Confirm that the F3AP message is for itself. . Thereafter, the IAB 1 (1210) MT part removes the header of the adaptation layer, and after receiver processing of the PDCP layer, the F3AP message including the RRC message for the IAB 2 (1200) is transferred to the IAB 1 (1210) DU part ( S1280)(IAB-node1 MT part learns the specific message type (F3AP message of IAB-node) according to the specific SRB or the message type indicator, and knows that the F3AP message is for itself from the routing information in the adaptation header. Then IAB-node 1 MT part removes the header of adaptation layer, and forwards the F3AP message which contains the RRC message for IAB-node 2 after receiver processing of the PDCP layer to IAB-node 1 DU part. part extracts the RRC message from F3-AP message).

The DU part of IAB 1 (1210) extracts an RRC message from the F3AP message (IAB-node1 DU parts send the RRC message (RRC connection setup) towards IAB-node 2).

As described above, the relay node includes the RRC message in the F3AP message and transmits it to the donor base station through the SRB.

Hereinafter, a protocol structure of a relay node supporting the above-described operation will be described. For convenience of description, the user plane protocol structure will be described below through an uplink data transmission operation. This is only for convenience of description, and the same method may be applied to the control plane protocol structure. In addition, although a protocol structure through two hops will be described below, a structure through hops set to an arbitrary number is also included in the scope of the present disclosure.

13 is a flowchart illustrating an operation in which a relay node transmits uplink user data according to an embodiment.

Referring to FIG. 13 , in a method of processing uplink user data, the relay node may perform a step of receiving uplink user data from the terminal ( S1300 ). As described above, the relay node may refer to an integrated access and backhaul (IAB) node that is connected to the terminal through radio access and is connected to another relay node or a donor base station through wireless backhaul. Alternatively, the relay node may refer to an IAB node connected to another relay node by wireless backhaul and also to a donor base station by wireless backhaul. The relay node receives uplink user data transmitted by the terminal to the donor base station.

The relay node may perform the step of deriving a terminal bearer identifier (UE-bearer-ID) by using logical channel identification information associated with the RLC PDU of uplink user data (S1310). When the uplink user data is received, the relay node extracts the terminal bearer identifier by using the logical channel identification information associated with the RLC PDU. That is, the relay node may check the terminal bearer identifier by using the logical channel identification information. As an example, the terminal bearer identifier may indicate a PDU session ID and a QoS flow indicator (QFI) indicated to identify the bearer of the corresponding terminal from the donor base station. As another example, the terminal bearer identifier may indicate a radio bearer identifier (drb-identiy) indicated to identify the bearer of the corresponding terminal from the donor base station. As another example, the terminal bearer identifier may indicate a GPRS Tunneling Protocol (GTP) tunnel endpoint identifier (TEID) allocated and indicated to identify a bearer of a corresponding terminal from a donor base station.

The relay node may select a backhaul RLC channel through which uplink user data will be transmitted based on at least one of the terminal bearer identifier and the donor base station address information (S1320). For example, the relay node may select a backhaul RLC channel mapped to the corresponding terminal bearer identifier by using the derived terminal bearer identifier. Alternatively, the relay node may select a backhaul RLC channel for transmitting uplink user data by using the donor base station address information. For example, the donor base station address information may be a GPRS Tunneling Protocol (GTP) tunnel endpoint identifier (TEID) received from the donor base station or an IP address of the donor base station. That is, the relay node may receive and store donor base station address information in advance.

Meanwhile, the relay node may select the backhaul RLC channel based on the backhaul RLC channel mapping information included in the terminal context setup message of the terminal received from the donor base station. That is, in order to select a backhaul RLC channel using at least one of the above-described terminal bearer identifier and donor base station address information, backhaul RLC channel mapping information is required. The relay node may receive backhaul RLC channel mapping information from the donor base station.

For example, the backhaul RLC channel mapping information may include N:1 (N is a natural number greater than or equal to 1) mapping information between at least one of a terminal bearer identifier and donor base station address information and a backhaul RLC channel. Alternatively, the backhaul RLC channel mapping information may include mapping information between the terminal bearer identifier and the donor base station address information.

Meanwhile, the backhaul RLC channel may be configured according to logical channel configuration information of the RRC message. That is, the relay node may configure the backhaul RLC channel by using the logical channel configuration information of the RRC message.

The relay node may transmit the uplink user data to the donor base station or another relay node through the selected backhaul RLC channel (S1330). The relay node transmits, in the uplink user data, at least one of the terminal bearer identifier, the donor base station address information, the logical channel identification information, and the mapping information between the logical channel identification information and the backhaul RLC channel in the adaptation entity of the relay node. . For example, when transmitting uplink user data through a backhaul RLC channel, the relay node may additionally add terminal bearer identifier information to uplink user data. The operation of adding terminal bearer identifier information may be performed in the adaptation entity of the relay node. Alternatively, the donor base station address information and the above-described mapping information are additionally included in the transmitted uplink user data, so that the donor base station or other relay node can utilize the corresponding information.

On the other hand, before the relay node receives the uplink user data from the terminal, the step of receiving the RRC connection request message from the terminal and the step of transmitting the RRC connection request message to the donor base station through a signaling radio bearer or F3AP message further include can do. As described with reference to FIGS. 10 to 12 , the relay node may include the RRC message of the terminal in the F3AP message and transmit it through the SRB. The signaling radio bearer or F3AP message may be configured to include donor base station address information in the adaptation entity.

As described above, when the uplink user data transmitted from the terminal to the donor base station is received, the relay node can classify and process the uplink user data using various information such as logical channel identification information and mapping information. That is, the relay node determines a donor base station or another relay node to which the uplink user data is to be transmitted, and transmits it through the selected backhaul RLC channel.

Hereinafter, various examples of the protocol for transmitting uplink user data described above will be described with reference to the drawings. For convenience of description, the relay node will be described below as an IAB node.

14 is a diagram exemplarily illustrating a protocol structure through which uplink user data is transmitted according to an embodiment.

Referring to FIG. 14 , the IAB 2 1410 receives uplink user data from the terminal 1400 through the DRB. The IAB 2 1410 derives a UE bearer identifier using logical channel identification information associated with the RLC PDU of the received uplink user data. In addition, the relay node selects a backhaul RLC channel through which uplink user data is to be transmitted based on at least one of the terminal bearer identifier and the donor base station address information.

The received uplink user data is transferred to the IAB 1 1420 through the MT part. In order to transmit uplink user data to IAB 1 1420 , IAB 2 1410 selects a backhaul RLC channel. In addition, IAB 2 (1410) is a terminal bearer identifier, donor base station 1430 address information, logical channel identification information, and mapping information between logical channel identification information and backhaul RLC channel in addition to the uplink user data transmitted to IAB 1 (1420). It may include at least one piece of information.

IAB 1 1420 transfers a message including uplink user data received from IAB 2 1410 to the DU 1431 of the donor base station 1430 . The DU 1431 of the donor base station 1430 delivers it to the CU 1432 through the IP layer.

15 is a diagram exemplarily illustrating a protocol structure through which uplink user data is transmitted in a donor base station having a single structure according to an embodiment.

Referring to FIG. 15 , the protocol structure of FIG. 14 and the terminal 1400 , IAB 2 1410 , and IAB 1 1420 are the same. However, the donor base station 1500 may not be divided into CU/DU. That is, the donor base station may perform operations from the SDAP layer to the MAC layer in one logical node. Other than that, the transmission path and operation of the uplink user data are the same as those of FIG. 14 and thus are omitted.

- Protocol structure embodiment for performing L3 forwarding in the IAB node

16 is a diagram exemplarily illustrating a protocol structure through which uplink user data is transmitted according to an embodiment.

Referring to FIG. 16 , (each) IAB nodes 1610 and 1620 may forward user data in L3 (IP layer) similarly to the conventional LTE RN. To this end, the first hop IAB nodes (IAB-1, 1610) having a direct wireless connection with the terminal 1600 must support a layer 2 function as well as a layer 3 or higher layer function. For example, IAB 1 1610 may configure/reconfigure a radio connection parameter to the terminal 1600 through an RRC connection reconfiguration message to the terminal 1600 . Through this, IAB 1 1610 supporting layer 3 can control a cell having its own cell identifier, and can make the terminal 1600 look like a normal base station. However, in this case, in processing user data, there is a problem that a delay for processing an IP packet may increase in addition to the layer 2 processing.

User data forwarding between IAB nodes (ex, between IAB 1 and IAB 2) is performed through GTP-U (or GTP-U/UDP/IP, if control plane data, GTP-C, GTP/SCTP protocol is used) protocol. can be Through this, differentiated/differentiated traffic processing for each radio bearer (or per flow) per user may be possible. For example, the IAB nodes 1610 and 1620 may identify them through the GTP TEID. To this end, the IAB nodes 1610 and 1620 may receive the GTP-TEID and the donor base station IP address as donor base station address information in advance. Normally, the GTP-TEID is information for unambiguously identifying the tunnel endpoint in the receiving GTP-U protocol entity, and the receiving side of the GTP tunnel locally allocates the TEID to be used by the transmitting side. In each network node, one GTP-U tunnel is identified with one TEID, one IP address, and one UDP port number. The TEID indicates the tunnel to which user data, which is the payload in the GTP-U tunnel, belongs.

In the present invention, the donor base station may allocate a TEID mapped to the terminal bearer identifier and deliver it to the access IAB node serving the terminal together with the donor base station IP address. In this case, the TEID and IP address may be transmitted through an RRC message or an F3AP message.

For another example, IAB nodes (1610, 1620) GTP TEID, PDU session ID, S-NSSAI, QoS flow indicator (QFI), QoS profile (eg 5QI, allocation and retention priority, Guaranteed Flow Bit Rate, Maximum Flow Bit Rate), DSCP, drb-identity, and mapping information for one or more of the SRB type can be used to distinguish them. For example, the IAB nodes 1610 and 1620 may receive the PDU session ID of the corresponding terminal and the uplink user data associated with the QFI from the terminal 1600 , map it to the GTP-TEID, and transmit it separately to the donor base station.

User data forwarding between IAB nodes (1610, 1620) and donor base station (DgNB) is via GTP-U (or GTP-U/UDP/IP, if control plane data, GTP-C, GTP/SCTP protocol is used) protocol. can be done Through this, differentiated/differentiated traffic processing for each radio bearer (or per flow) per user may be possible. For example, this may be identified through the GTP TEID. As another example, this may be distinguished through mapping information for one or more of GTP TEID, PDU session ID, S-NSSAI, and QFI.

As an example, the above-described mapping information may be indicated to the IAB node through OAM. As another example, the above-described mapping information may be indicated to the IAB node by the donor base station through an RRC message. As another example, the above-described mapping information may be indicated to the IAB node by the donor base station through the F3AP message. As another example, the above-described mapping information includes E-RAB, PDU session resource information (eg, PDU session ID, S-NSSAI, etc.), QFI/QCI, associated QoS profile, Diffserv code point (DSCP), TEID, Transport layer Address (eg, donor base station IP address), drb-identity, and mutual mapping information between one or more of SRB type may be included. Specifically, for example, it may include QFI and Transport layer Information (TEID, Transport layer Address) mapping information. Alternatively, it may include mapping information between DSCP and radio bearer identification information (drb-identity or SRB type). Alternatively, it may include mapping information between QFI and radio bearer identification information (drb-identity or SRB type). Accordingly, PDU session resource information (eg, PDU session ID, S-NSSAI, etc.) included in the GTP-U header, QFI/QCI, associated QoS profile, Diffserv code point (DSCP), TEID, Transport layer Address, drb A field including one or more of -identity and SRB type information is associated with one flow/bearer on the interface between the IAB nodes or the interface between the IAB and the donor base station. And PDU session resource information (eg, PDU session ID, S-NSSAI, etc.), QFI / QCI, associated QoS profile, DSCP (Diffserv code point), TEID, Transport layer Address, at least one of drb-identity and SRB type The information may be used to identify a radio bearer of the air interface between the terminal and the IAB node. As an example, the IAB nodes 1610 and 1620 receive the uplink user data associated with the PDU session ID and QFI of the corresponding terminal from the terminal 1600, map it to the GTP-TEID, the donor base station IP address, and transmit it separately to the donor base station. can

- Protocol structure embodiment for performing L3 forwarding in the first hop IAB node connected to the terminal and L2 forwarding in other IAB nodes

17 is a diagram exemplarily illustrating a protocol structure through which uplink user data is transmitted according to an embodiment.

Referring to FIG. 17 , the first hop IAB node 1710 configuring a direct wireless connection with the terminal 1600 may forward user data in L3 (IP layer) similarly to the conventional LTE RN. To this end, the first hop IAB nodes (IAB 1, 1710) having a direct wireless connection with the terminal 1600 must support a layer 2 function as well as an upper layer function of a layer 3 or higher. For example, IAB 1 1710 may configure/reconfigure radio connection parameters to the terminal 1600 through an RRC connection reconfiguration message. Through this, the IAB 1 1710 supporting layer 3 can control a cell having its own cell identifier, and can make the terminal 1600 look like a normal base station. However, in this case, there is a problem that a delay for IP packet processing may increase in addition to layer 2 processing.

Between the first hop IAB node 1710 and the donor base station 1730 having a direct wireless connection with the terminal 1600, GTP-U (or GTP-U/UDP/IP, if control plane data, GTP-C, GTP) User data can be transmitted through the /SCTP protocol) protocol. For example, the first hop IAB node 1710 and the donor base station 1730 having a direct radio connection with the terminal 1600 process differentiated/differentiated traffic for each radio bearer (or per flow) per user through the GTP TEID. may be possible For another example, the IAB node 1710 and the donor base station 1730 are GTP TEID, Transport layer Address (eg donor base station IP address), PDU session ID, S-NSSAI, QoS flow indicator (QFI), associated QoS profile, Through mapping information on at least one of DSCP, drb-identity, and SRB type, it is possible to classify traffic for each radio bearer for each user. For example, the first hop IAB node 1710 receives the PDU session ID and QFI of the corresponding terminal from the terminal 1600, and maps it to the GTP-TEID and the donor base station IP address, and classifies it as a donor base station. can be transmitted As another example, when the first hop IAB node 1710 divides and forwards user data in the RLC layer as shown in FIGS. 18 to 19 , the first hop IAB node 1710 receives the PDU session ID of the corresponding terminal from the terminal 1600. It is possible to receive uplink user data associated with logical channel identification information mapped to QFI or terminal bearer identifier, and map it to GTP-TEID and donor base station IP address, and then transmit it to the donor base station.

Meanwhile, user data forwarding of the IAB nodes IAB 2 and 1720 rather than the first hop IAB node 1710 having a direct wireless connection with the terminal 1600 may be performed on an L2-based basis. For example, as shown in FIG. 17 , user data may be forwarded in the SDAP layer. Through this, data forwarding that satisfies QoS for each flow can be performed. Each QoS flow processes corresponding data forwarding through a corresponding QoS parameter/profile (eg, one or more parameters of 5G QoS Identifier, Allocation and Retention Priority, Guaranteed Flow Bit Rate, Maximum Flow Bit Rate, and Reflective QoS Attribute) may be performed, and may be mapped to a DRB according to a QoS profile associated with a QoS flow indicator (QFI). However, since the IAB 2 node 1720 may not be able to distinguish data for each terminal, the transmission SDAP entity or the adaptation layer entity above the SDAP may add a terminal identifier for classification for each terminal and transmit. The flow/data mapped based on the terminal identifier added in the IAB 2 node 1720 may be selected. The receiving SDAP entity or the adaptation layer entity above the SDAP may remove the UE identifier for identification for each UE and transmit it to a higher layer.

Alternatively, the IAB 2 node 1720 of FIG. 17 may operate without an SDAP layer. That is, the IAB 2 node 1720 may forward user data in the PDCP layer. Through this, data forwarding that distinguishes radio bearers can be performed, and ciphering and/or integrity protection can be provided in each link. However, since the IAB 2 node 1720 may not be able to distinguish each terminal, the transmission SDAP entity or the adaptation layer entity between the SDAP and the PDCP entity or the PDCP entity adds a terminal identifier for each terminal and transmits, and the IAB 2 node In step 1720, a mapped radio bearer is selected based on this, and a UE identifier for identification for each UE is removed from the receiving SDAP entity or the adaptation layer entity between the SDAP and the PDCP entity or the PDCP entity and transmitted to the upper layer.

Alternatively, the IAB 2 node 1720 of FIG. 17 may operate without an SDAP layer and a PDCP layer. In addition, user data may be forwarded on an adaptation layer above RLC or on an RLC layer or an adaptation layer on an RLC layer and a MAC layer or on a MAC layer. Through this, data forwarding that distinguishes the radio bearer/RLC bearer/logical channel may be performed. However, since the IAB 2 node 1720 cannot distinguish each terminal, an adaptation layer entity above the transmission RLC or an RLC layer entity or an adaptation layer entity on the RLC layer and the MAC layer or a MAC entity for each terminal is a terminal bearer identifier. can be sent by adding The IAB 2 node 1720 selects a mapped radio bearer based on the terminal bearer identifier, and an adaptation layer entity or RLC layer entity above the receiving RLC of the donor base station 1730 or an adaptation layer entity on the RLC layer and the MAC layer or MAC layer The UE must remove the UE bearer identifier for identification by UE from the entity and transmit it to a higher layer.

Alternatively, L2 forwarding in the IAB 2 node 1720 may be provided with reference to embodiments described below (IAB node performing L2 forwarding-1, IAB node performing L2 forwarding-2). Details will be described in the following examples.

- IAB Perform L2 forwarding on node-1 ( RLC on top adaptation Layer Protocol structure example for application)

18 is a diagram exemplarily illustrating a protocol structure through which uplink user data is transmitted according to an embodiment. 19 is a diagram exemplarily illustrating a protocol structure through which uplink user data is transmitted according to an embodiment.

As shown in FIG. 18 , the IAB nodes 1810 and 1820 may forward user data by dividing the user data from the layer 2 entity (sub layer 2 entity).

For example, the IAB nodes 1810 and 1820 may divide and forward user data in the RLC layer. For another example, as shown in FIG. 18 , the IAB nodes 1810 and 1820 may place an adaptation layer above the RLC layer to classify and forward user data on the corresponding adaptation layer. For another example, as shown in FIG. 19 , the IAB nodes 1910 and 1920 may place an adaptation layer below the RLC layer (or above the MAC layer) and divide and forward user data on the RLC layer.

Meanwhile, for convenience of description, a method in which the terminal transmits uplink data to the donor base station through the IAB node will be described. This is for convenience of description and downlink data transmission may be provided similarly.

If the adaptation layer exists above the RLC layer as shown in FIG. 18, a first hop IAB node (IAB) that enables direct radio connection of an RLC bearer (or radio bearer) for each UE to the UE 1600 (for uplink data) 1, 1810) RLC bearer (or radio bearer) on the interface between IAB nodes (between IAB 1 and IAB 2) in the adaptation layer entity of 1, 1810, or RLC bearer (or radio bearer) between IAB nodes 1810, 1820 and the donor base station 1830 ) needs to be mapped. Here, the RLC bearer (RLC channel) indicates a lower layer part of the radio bearer configuration consisting of RLC and logical channel configuration. In uplink data transmission through the IAB node, for example, on the wireless backhaul interface between IAB 1 and IAB 2, a logical connection or a corresponding channel between the transmitting RLC entity of IAB 1 and the receiving RLC entity of IAB 2 is indicated. For convenience of description, in this specification, an RLC bearer and a radio bearer may be used interchangeably. For example, an RLC bearer may be denoted as a radio bearer, and a radio bearer may be denoted as an RLC bearer. The RLC bearer may be replaced with a radio bearer, and the radio bearer may be replaced with an RLC bearer.

If there is no specific limit to the number of RLC bearers (or radio bearers) that can be provided on the interface between IAB nodes (between IAB 1 and IAB 2) or between the IAB node and the donor base station (between IAB 2 and DgNB), the terminal RLC bearer (or radio bearer) on the interface between RLC bearer (or radio bearer) per UE and IAB node (between IAB 1 and IAB 2) in the adaptation layer entity of the first hop IAB node (IAB 1) having direct radio connection with can be configured to map one-to-one. For example, the one-to-one mapping configuration may be configured by the donor base station to the IAB 1 node through an RRC message. As another example, the one-to-one mapping configuration may be configured by the donor base station to the IAB 1 node through an F3AP message. As another example, the one-to-one mapping configuration may be configured by indicating mapping information from the OAM to the IAB 1 node.

Alternatively, the RLC bearer (or radio bearer) for each UE and the RLC bearer (or radio bearer) between the IAB node and the donor base station (between IAB 2 and the DgNB) may be configured to be mapped one-to-one. As an example, the one-to-one mapping configuration may be configured by the donor base station transmitting an RRC message to the IAB 2 node. As another example, the one-to-one mapping configuration may be configured by the donor base station to the IAB 2 node through an F3AP message. As another example, the one-to-one mapping configuration may be configured by indicating mapping information from the OAM to the IAB 1 node.

If there is a specific limitation on the number of RLC bearers (or radio bearers) that can be provided on the interface between the IAB nodes (between IAB 1 and IAB 2) or between the IAB node and the donor base station (between IAB 2 and the DgNB), the terminal In the adaptation layer entity of the first hop IAB node (IAB 1) having a direct radio connection with or between the RLC bearer (or radio bearer) for each UE and the donor base station (between IAB 2 and DgNB) in the IAB node (IAB 2) located in the middle, it is necessary to map the RLC bearer (or radio bearer) to N:1. . Here, N represents any natural number.

Currently, there is a restriction on the maximum number of radio bearers that can be provided between the terminal and the base station (or the maximum number of radio bearers that the terminal can provide). For example, in LTE, the maximum number of DRBs that can be provided is 8. In the case of NR, the maximum number of DRBs that can be provided is only 32. Therefore, when the IAB node accommodates multiple IAB nodes and terminals and relays them to the donor base station, if the maximum number of DRBs that the IAB node can provide is the same as the maximum number of DRBs that the general terminal can provide, the IAB node and A problem of limiting the number of RLC bearers/radio bearers mapped to a UE capable of providing relay between IAB nodes or between an IAB node and a donor base station and a radio bearer may occur.

For example, let's assume the following situation: IAB 1 node is connected to terminal-1, terminal-2, and terminal-3, and three radio bearers (radio bearer-1, radio bearer-2, radio bearer-3) are configured in terminal-1. And, two radio bearers (radio bearer-a, radio bearer-b) are configured in terminal-2. And, two radio bearers (radio bearer-A, radio bearer-B) are configured in terminal-3. And, there is no terminal directly connected to the IAB 2 node, and there is no IAB node directly connected to the IAB 2 other than IAB 1. There is no terminal directly connected to the donor base station, and there is no IAB node directly connected to IAB 2 other than IAB 2.

In the above assumption, for uplink data processing, the number of transmit RLC entities of UE-1 is three, the number of transmit RLC entities of UE-2 is two, and the number of transmit RLC entities of UE3 is two. The number of receiving RLC entities of the peered IAB 1 node is 3 (terminal-1 peering entity), 2 (terminal-2 peering entity), and 2 (terminal-3 peering entity), respectively. The donor base station may determine the number of transmitting RLC entities for data transmission from the IAB 1 node to the IAB 2 node. For example, the number of radio bearers/RLC bearers capable of the same packet forwarding processing may be determined according to the type/property of the radio bearer/RCL bearer to be provided for each UE. For example, radio bearer-1 of terminal-1, radio bearer-a of terminal-2, and radio bearer-A of terminal-3 are radio bearers capable of the same packet forwarding processing (eg, the default bearer of the same PDU session, or the same If the service provision is a radio bearer), three radio bearers/RLC bearers are used as one transmitting RLC entity from the IAB -1 node to the IAB 2 node (or one RLC bearer on the interface between the IAB 1 nodes and the IAB 2 nodes) You can process/pass data by mapping to . This may be provided by the adaptation layer entity. Accordingly, the receiving RLC entity (RLC-RX1) peered from the IAB 1 node to the transmitting RLC entity (RLC-TX1) of the UE-1 radio bearer-1 is one transmitting RLC entity (for convenience of description) to the IAB 2 node. RLC entity-11). The receiving RLC entity (RLC-RXa) peered to the transmitting RLC entity (RLC-TXa) of the UE-2 radio bearer-a in the IAB-1 node maps to the same transmitting RLC entity (RLC entity-11) to the IAB2 node can be The receiving RLC entity (RLC-RXA) peered to the transmitting RLC entity (RLC-TXA) of UE-3 radio bearer-A in the IAB 1 node maps to the same transmitting RLC entity (RLC entity-11) to the IAB-2 node can be

Meanwhile, in the uplink data transmission, the RLC entity (or RLC configuration information) in the terminal may be identified by logical channel identification information. Therefore, the mapping between the receiving RLC entity of the IAB 1 node peered to the RLC entity of the specific radio bearer/RLC bearer of the specific terminal and the transmitting RLC entity of the IAB 1 node peered to the receiving RLC entity of the IAB 2 node is each logical channel identification information. can be provided in conjunction with For example, the donor base station may provide this by configuring the mapping information between the logical channel identification information of a specific radio bearer / RLC bearer of a specific terminal and the logical channel identification information of the RLC bearer on the radio interface between IAB-1 and IAB 2 in IAB 1. have. This may be indicated to the IAB-1 node in the donor base station through an RRC message or an F3AP message. The donor base station may indicate configuration information including mapping information corresponding to the IAB node when instructing the RRC message to the terminal in order to configure radio resources in the terminal. For example, when the donor base station transmits the RRC reconfiguration message of the corresponding terminal to the terminal through the IAB node, the corresponding mapping information to the IAB node may be included through the F3AP message including the corresponding RRC reconfiguration message.

In another method, the RLC entity in the UE may be identified by radio bearer identification information associated with the PDCP entity. For example, the donor base station instructs/configures mapping information between the radio bearer identification information of a specific radio bearer/RLC bearer of a specific terminal and logical channel identification information (or radio bearer identification information) on the radio interface between IAB 1 and IAB 2 to IAB 1. By doing so, it is possible to provide radio bearer identification information associated with the PDCP entity.

The UE radio bearer identification information associated with the PDCP entity may be provided by being included in the adaptation layer configuration information on the RRC message for IAB 1 radio resource configuration. Alternatively, the UE radio bearer identification information associated with the PDCP entity may be provided by being included in the RLC configuration information on the RRC message for IAB 1 radio resource configuration. Alternatively, the terminal radio bearer identification information associated with the PDCP entity may be provided by being included in the logical channel configuration information on the RRC message for IAB 1 radio resource configuration. Alternatively, the UE radio bearer identification information associated with the PDCP entity may be included and provided in the F3AP message transmitted to the IAB1 node. The configuration information/mapping information includes the terminal identifier, the radio bearer identifier/logical channel identification information of the corresponding terminal, and logical channel identification information (or radio bearer identification information) for the RLC bearer on the radio interface between IAB 1 and IAB 2 mapped thereto. may include Mapping information may be indicated to the IAB 1 node in the donor base station through an RRC message or an F3AP message. When the donor base station instructs the terminal an RRC message to configure radio resources to the terminal, the donor base station may indicate configuration information including mapping information corresponding to the IAB 1 node. For example, when the donor base station transmits the RRC reconfiguration message of the corresponding terminal to the terminal through the IAB node, the corresponding mapping information to the IAB node may be included through the F3AP message including the corresponding RRC reconfiguration message.

As another method, when the first hop IAB node classifies data for each radio bearer of the terminal through GTP TEID as shown in FIGS. 15 to 17 and transmits it to the donor base station, the RLC entity (or RLC configuration information) of the terminal in the IAB1 node is mapped to the GTP TEID, so that the radio bearer for each terminal can be classified and transmitted. The mapping between the TEID in the IAB1 node and the sending RLC entity of the IAB 1 node peered to the receiving RLC entity of the IAB 2 node may be provided by associating the GTP TEID and the donor base station IP address with logical channel identification information. For example, the donor base station is a TEID mapped to a specific radio bearer / RLC bearer of a specific terminal, and the logical channel identification information (or radio bearer identification information) on the radio interface between the donor base station IP address and IAB 1 and IAB 2 Mapping information between IAB 1 can be instructed/configured in . The corresponding information may be provided by being included in the adaptation layer configuration information on the RRC message for IAB 1 radio resource configuration. Alternatively, it may be provided by being included in the RLC configuration information on the RRC message for IAB 1 radio resource configuration. Alternatively, it may be provided by being included in the logical channel configuration information on the RRC message for IAB 1 radio resource configuration. Alternatively, it may be provided included in the F3AP message transmitted to the IAB 1 node. The corresponding configuration information/mapping information includes the terminal identifier, the TEID associated with the radio bearer identifier/logical channel identification information of the corresponding terminal, the donor base station IP address, and the logical channel identification for the RLC bearer on the radio interface between IAB 1 and IAB 2 mapped thereto. information (or radio bearer identification information). Mapping information may be indicated to the IAB 1 node in the donor base station through an RRC message or an F3AP message. When the donor base station instructs the terminal an RRC message to configure radio resources to the terminal, the donor base station may indicate configuration information including mapping information corresponding to the IAB 1 node. For example, when the donor base station transmits the RRC reconfiguration message of the corresponding terminal to the terminal through the IAB node, the corresponding mapping information to the IAB node may be included through the F3AP message including the corresponding RRC reconfiguration message.

Similar to the method described above, an RLC bearer (or RLC bearer (or radio bearer) for each UE in the IAB node (IAB 2) located in the middle) on the interface between the IAB nodes (between IAB 1 and IAB 2) is performed between the IAB node and the donor base station. Information for mapping to the RLC bearer (or radio bearer) (between IAB 2 and DgNB) is required. For example, the donor base station may determine the number of radio bearers/RLC bearers capable of the same packet forwarding processing in the IAB node (IAB 2) located in the middle according to the radio bearer/RCL bearer type/attribute to be provided for each terminal. Alternatively, the donor base station is a radio bearer/RLC bearer capable of the same packet forwarding processing in the intermediate IAB node (IAB 2) according to the radio bearer/RCL bearer type/property provided by the IAB node (IAB 1) connected to the lower layer. number can be determined.

In uplink data transmission, the RLC entity (or RLC configuration information) in the terminal may be identified by logical channel identification information. Therefore, mapping information for instructing to transmit data belonging to a specific radio bearer/RLC bearer of a specific terminal from the IAB node to the next hop IAB node (or the donor base station if the next hop is a donor base station) is provided through logical channel identification information. can For example, the donor base station provides mapping information between the logical channel identification information of a specific radio bearer/RLC bearer of a specific terminal and the logical channel identification information of the RLC bearer on the radio interface between IAB 2 and the donor base station to IAB 2 by instructing/configuring it. can This may be indicated to the IAB 2 node in the donor base station through an RRC message or an F3AP message. The donor base station may indicate configuration information including mapping information corresponding to the IAB node when instructing the terminal an RRC message to configure radio resources to the terminal.

In another method, the RLC entity in the UE may be identified by radio bearer identification information associated with the PDCP entity. For example, the donor base station instructs/configures mapping information between the radio bearer identification information of a specific radio bearer/RLC bearer of a specific terminal and logical channel identification information (or radio bearer identification information) on the air interface between IAB 1 and IAB 2 to IAB 2 This can be provided by

The mapping information may be provided by being included in the adaptation layer configuration information. The mapping information includes the terminal identifier, the radio bearer identifier/logical channel identification information of the corresponding terminal, and logical channel identification information (or radio bearer identification information) for the RLC bearer on the radio interface between the IAB-2 and the donor base station mapped thereto. can IAB-2 may transmit the corresponding data to the corresponding MAC entity according to the mapping information according to the configured mapping information.

The donor base station adaptation layer entity may transmit the corresponding data to the associated PDCP entity based on the terminal identifier and logical channel identification information (or radio bearer identification information) included in the received data.

As another example, mapping information between the logical channel identification information of the RLC bearer on the radio interface between IAB 1 and IAB 2 and the logical channel identification information of the RLC bearer on the radio interface between IAB 2 and the donor base station may be configured in IAB 2. Mapping information may be indicated from the donor base station to the IAB 2 node through an RRC message or an F3AP message. This is when the donor base station instructs the IAB 1 node through the RRC message or when the RRC message is instructed to the terminal to configure radio resources to the terminal, the configuration information including the mapping information corresponding to the IAB 2 node is transmitted through the F3AP message. can direct

In another method, the RLC entity in the UE may be identified by radio bearer identification information associated with the PDCP entity. For example, the donor base station configures mapping information between the radio bearer identification information of the RLC bearer on the radio interface between IAB 1 and IAB 2 and the logical channel identification information (or radio bearer identification information) on the radio interface between IAB 2 and the donor base station in IAB 2. This can be provided by IAB 2 may add one or more pieces of information to the corresponding data to the header according to the configured mapping information, and deliver the header-added data to the corresponding MAC entity. The donor base station adaptation layer entity may transmit the corresponding data to the associated PDCP entity based on the terminal bearer identifier and logical channel identification information (or radio bearer identification information) included in the received data.

As another method, as shown in FIGS. 15 to 17 , when the first hop IAB node classifies data for each radio bearer of the terminal through GTP TEID and transmits it to the donor base station, the IAB2 node is the RLC entity of the terminal (or RLC configuration information) Using the GTP TEID mapped to and the donor base station IP address, the radio bearer for each terminal can be classified and transmitted. The IAB1 node adds the TEID and the donor base station IP address to the header for user data (eg, IP packet) through the radio bearer for each terminal in the adaptation layer and transmits it. The adaptation layer of the IAB 2 node may transmit the TEID and the donor base station IP address by linking the logical channel identification information of the transmitting RLC entity. For example, the donor base station may indicate/configure mapping information between a TEID mapped to a specific radio bearer/RLC bearer of a specific terminal and logical channel identification information (or radio bearer identification information) on the radio interface between IAB 2 and the donor base station. can The corresponding information may be provided by being included in the adaptation layer configuration information on the RRC message for IAB 2 radio resource configuration. Alternatively, it may be provided by being included in the RLC configuration information on the RRC message for IAB 2 radio resource configuration. Alternatively, it may be provided by being included in logical channel configuration information on the RRC message for IAB 2 radio resource configuration. Alternatively, it may be provided by being included in the F3AP message between the donor base station and the IAB2 node. The corresponding configuration information/mapping information includes the terminal identifier, the TEID associated with the radio bearer identifier/logical channel identification information of the corresponding terminal, the donor base station IP address, and the logical channel identification for the RLC bearer on the radio interface between IAB 2 and the donor base station mapped thereto. information (or radio bearer identification information). Mapping information may be indicated to the IAB 2 node in the donor base station through an RRC message or an F3AP message. When the donor base station instructs the terminal to an RRC message to configure radio resources, the donor base station may indicate configuration information including mapping information corresponding to the IAB 2 node through the F3AP message.

- IAB Perform L2 forwarding on node-2 ( RLC in the lower adaptation Layer Application) Protocol Structure Example

As another example, if an adaptation layer is configured between the MAC and RLC layer as shown in FIG. 19 (or if an adaptation function is provided using a MAC header on the MAC layer), a radio bearer for each UE is directly connected to the UE for uplink data. In the adaptation layer entity of the first hop IAB node (IAB 1) with The number of RLC entities (RLC bearers) of radio bearers on the IAB inter-node interface or the number of RLC entities (or number of RLC bearers) of radio bearers between the IAB node and the donor base station is the number of RLC entities per radio bearer (RLC per UE) of the IAB 1 node. number of bearers). For example, IAB 1 node is connected to UE-1 and UE-2, UE-1 is configured with two radio bearers and UE-2 has three radio bearers. And, it is assumed that there is no terminal directly connected to IAB 2 node, and there is no IAB node directly connected to IAB 2 other than IAB 1. If there is no terminal directly connected to the donor base station and there is no IAB node directly connected to IAB-2 other than IAB-2, the number of RLC entities in terminal 1 is 2 and the number of RLC entities in terminal 2 is 3 for uplink data processing. And the number of receiving RLC entities of the IAB 1 node receiving the data of the terminal 1 and the terminal 2 becomes 5 by adding 2 and 3. The number of RLC entities transmitting from the IAB 1 node to the IAB 2 node is also 5. The number of receiving RLC entities of the IAB 2 node is also 5. The number of transmitting RLC entities from the IAB 2 node to the donor base station is also 5, and the number of receiving RLC entities of the donor base station is also 5. The number of RLC bearers on each interface is the same.

If an adaptation layer is configured between the MAC and RLC layer (or an adaptation function is provided using a MAC header on the MAC layer), the UE and the donor base station have a PDCP entity for each radio bearer, Since the radio bearer is mapped one-to-one to the PDCP entity to the RLC entity, it is necessary to configure an RLC entity equal to the number of radio bearers between the UE and the base station in the IAB node as well.

Through this, the IAB node transmits MAC SDUs belonging to different radio bearers (or belonging to different logical channels) within one terminal on the interface between the IAB node and the IAB node or on the interface between the IAB node and the donor base station through the same transport channel. It can be transmitted by multiplexing.

The IAB node may multiplex and transmit MAC SDUs of different terminals through the same transport channel on the interface between the IAB node and the IAB node or on the interface between the IAB node and the donor base station.

The IAB node transmits MAC SDUs belonging to different radio bearers (or belonging to different logical channels) of different terminals through the same transmission channel on the interface between the IAB node and the IAB node or on the interface between the IAB node and the donor base station. can

For example, a UE identifier (UE ID) and radio bearer identification information (data radio bearer identification information or SRB identification information)/a header including logical channel identification information is added. The transmission adaptation entity transmits the header-added data to the transmission MAC entity, and identifies the logical channel associated therewith using at least one of a UE ID and radio bearer identification information/logical channel identification information in the transmission MAC entity. Information can be added on the MAC header. A message to which the MAC header is added is transmitted by multiplexing through the same transport channel on the interface between the IAB node and the IAB node or on the interface between the IAB node and the donor base station. The receiving MAC entity can use one or more of the UE ID and radio bearer identification information/logical channel identification information to check the logical channel identification information associated therewith to classify and process data for each radio bearer for each UE. . The receiving MAC entity processes the received data and forwards it to the receiving adaptation layer entity. The reception adaptation layer entity transmits data (RLC PDU) (with the adaptation header removed) to the reception RLC entity mapped to the UE identifier and the radio bearer identifier/logical channel identification information.

As another example, when the MAC entity provides the transmission adaptation layer function, for data (eg, RLC PDU) received from the RLC entity configured for each radio bearer for each UE, a header field including a UE identifier (UE ID) in the transmitting MAC entity add In addition, by using one or more of a terminal identifier (UE ID) and radio bearer identification information (data radio bearer identification information or SRB identification information)/logical channel identification information in the transmitting MAC entity, logical channel identification information associated therewith is stored in the MAC header add on top This is multiplexed and transmitted through the same transmission channel on the interface between the IAB node and the IAB node or on the interface between the IAB node and the donor base station. The receiving MAC entity can use at least one of a UE identifier (UE ID) and radio bearer identification information/logical channel identification information to classify and process data for each radio bearer per UE through logical channel identification information associated therewith. After processing the received data, the receiving MAC entity transfers data (RLC PDU) to the receiving RLC entity mapped to the UE identifier and radio bearer identifier/logical channel identification information (with the adaptation header removed).

Currently, there is a limit to the maximum number of radio bearers that can be provided between the terminal and the base station. For example, in LTE, the maximum number of DRBs that can be provided is 8. In the case of NR, the maximum number of DRBs that can be provided is only 32. Therefore, when the IAB node accommodates multiple IAB nodes and terminals and relays them to the donor base station, if the maximum number of DRBs that the IAB node can provide is the same as the maximum number of DRBs that the general terminal can provide, the IAB node A problem may occur in that the number of terminals and radio bearers that can provide relays between the and the IAB node or between the IAB node and the donor base station is limited.

As an example to solve this problem, a radio bearer on the air interface between the first hop IAB node (IAB 1) having a direct radio connection with the terminal in the terminal is set as a radio bearer on the air interface between the IAB node and the IAB node, or between the IAB node and the donor base station. It can be mapped to a bearer.

For example, let's assume the following situation:

Terminal-1, terminal-2, and terminal-3 are connected to the IAB 1 node, and three radio bearers (radio bearer-1, radio bearer-2, radio bearer-3) are configured in terminal-1. And, two radio bearers (radio bearer-a, radio bearer-b) are configured in terminal-2. And, two radio bearers (radio bearer-A, radio bearer-B) are configured in terminal-3. And, there is no terminal directly connected to the IAB 2 node, and there is no IAB node directly connected to the IAB 2 other than IAB 1. There is no terminal directly connected to the donor base station, and there is no IAB node directly connected to IAB 2 other than IAB 2.

In this case, for uplink data processing, the number of transmission RLC entities in UE-1 is 3, the number of transmission RLC entities in UE-2 is 2, and the number of transmission RLC entities in UE-3 is 2. The number of receiving RLC entities of the peered IAB 1 node is 3, 2, and 2, respectively. The donor base station may determine the number of transmitting RLC entities from the IAB 1 node to the IAB 2 node. For example, the number of radio bearers capable of performing the same packet forwarding process may be determined according to the type of radio bearer to be provided for each UE. For example, radio bearer-1 of terminal-1, radio bearer-a of terminal-2, and radio bearer-A of terminal-3 are radio bearers capable of the same packet forwarding processing (eg, the default bearer of the same PDU session, or the same If the service provision is a radio bearer), the three radio bearers may be mapped to one RLC entity when transmitting from the IAB 1 node to the IAB 2 node. Accordingly, the receiving RLC entity (RLC-RX1) peered from the IAB 1 node to the transmitting RLC entity (RLC-TX1) of the UE-1 radio bearer-1 is one transmitting RLC entity (for convenience of description) to the IAB 2 node. RLC entity-11). The receiving RLC entity (RLC-RXa) peered to the transmitting RLC entity (RLC-TXa) of the UE-2 radio bearer-a in the IAB 1 node is to be mapped to the same transmitting RLC entity (RLC entity-11) to the IAB 2 node. can The receiving RLC entity (RLC-RXA) peered to the transmitting RLC entity (RLC-TXA) of UE-3 radio bearer-A in the IAB 1 node is to be mapped to the same transmitting RLC entity (RLC entity-11) to the IAB 2 node. can

In the terminal, the RLC entity may be identified by logical channel identification information. Therefore, the mapping between the RLC entity of the IAB 1 node peered to the RLC entity of the radio bearer for each UE and the RLC entity of the IAB 1 node peered to the RLC entity of the IAB 2 node may be provided through logical channel identification information. As an example, the donor base station may provide mapping information between logical channel identification information of the terminal and logical channel identification information on the air interface between IAB 1 and IAB 2 by configuring in IAB 1 .

In another method, the RLC entity in the UE may be identified by radio bearer identification information associated with the PDCP entity. For example, the donor base station may provide this by configuring the mapping information between the radio bearer identification information of the terminal and the logical channel identification information on the radio interface between IAB 1 and IAB 2 in IAB 1. This may be indicated to the IAB 1 node in the donor base station through the RRC message. When the donor base station instructs the UE to an RRC message for configuring radio resources, the donor base station may indicate configuration information including mapping information corresponding to the IAB 1 node through the F3AP message.

For example, the donor base station adaptation layer entity may transmit the corresponding data to the associated RLC entity based on the terminal identifier or logical channel identification information (or radio bearer identification information) included in the received data. As another example, the adaptation layer divides data for each RLC bearer/radio bearer/logical channel identification information and buffers/stores/processes it, so that the reception adaptation layer can deliver it to the RLC bearer for each associated UE.

Similar to the method described above, the RLC bearer on the interface between the IAB nodes (between IAB 1 and IAB 2) (or the RLC bearer for each UE in the IAB node (IAB 2) located in the middle) is transferred between the IAB node and the donor base station (IAB 2 and DgNB). Inter) There is also a method of configuring information for mapping to the RLC bearer.

In the uplink data transmission, the RLC entity (or RLC configuration information) in the terminal may be identified by logical channel identification information. Therefore, mapping information for instructing to transmit data belonging to a specific radio bearer/RLC bearer of a specific terminal from the IAB node to the next hop IAB node (or the donor base station if the next hop is a donor base station) is provided through logical channel identification information. can For example, the donor base station may provide this by configuring the mapping information between the logical channel identification information of a specific radio bearer / RLC bearer of a specific terminal and the logical channel identification information of the RLC bearer on the radio interface between IAB 2 and the donor base station in IAB 2. . This may be indicated to the IAB 2 node in the donor base station through an RRC message or an F3AP message. Alternatively, when the donor base station instructs the RRC message to the terminal in order to configure radio resources to the terminal, the donor base station may indicate configuration information including mapping information to the IAB node through the F3AP message.

In another method, the RLC entity in the UE may be identified by radio bearer identification information associated with the PDCP entity. For example, the donor base station configures mapping information between the radio bearer identification information of a specific radio bearer/RLC bearer of a specific terminal and logical channel identification information (or radio bearer identification information) on the radio interface between IAB 1 and IAB 2 in IAB 1 can provide

This may be provided by being included in the adaptation layer configuration information. The corresponding configuration information/mapping information includes the terminal identifier or radio bearer identifier/logical channel identification information of the corresponding terminal, and logical channel identification information (or radio bearer identification information) for the RLC bearer on the radio interface between the IAB 2 node and the donor base station mapped thereto. may include. IAB 2 may deliver the corresponding data to the corresponding MAC entity according to the configured mapping information.

For example, the donor base station adaptation layer entity may transmit the corresponding data to the associated RLC entity based on the terminal identifier or logical channel identification information (or radio bearer identification information) included in the received data. As another example, the adaptation layer divides data for each RLC bearer/radio bearer/logical channel identification information and buffers/stores/processes it, so that the reception adaptation layer can deliver it to the RLC bearer for each associated UE.

As another example, mapping information between the logical channel identification information of the RLC bearer on the radio interface between IAB 1 and IAB 2 and the logical channel identification information of the RLC bearer on the radio interface between IAB 2 and the donor base station can be provided by configuring in IAB 2. This may be indicated to the IAB 2 node in the donor base station through the RRC message. Alternatively, when the donor base station instructs the IAB 1 node through the RRC message or when instructing the RRC message to configure the radio resource to the terminal, configuration information including mapping information corresponding to the IAB 2 node may be indicated.

In another method, the RLC entity in the UE may be identified by radio bearer identification information associated with the PDCP entity. For example, the donor base station configures mapping information between the radio bearer identification information of the RLC bearer on the radio interface between IAB 1 and IAB 2 and the logical channel identification information (or radio bearer identification information) on the radio interface between IAB 2 and the donor base station in IAB 2. This can be provided by IAB 2 may add mapping information to the corresponding data to the header according to the configured mapping information and deliver it to the corresponding MAC entity. The donor base station adaptation layer entity may transmit the corresponding data to the associated PDCP entity based on the terminal identifier or logical channel identification information (or radio bearer identification information) included in the received data.

When the protocol structure and the RRC message processing method described above are applied, there is an effect that the terminal can effectively establish a connection to the base station through a multi-hop relay node under the control of the donor base station to transmit and receive data.

Hereinafter, a configuration of a relay node capable of performing some or all of the above-described embodiments will be briefly described once again with reference to the drawings.

20 is a diagram showing the configuration of a relay node 2000 according to another embodiment.

Referring to FIG. 20 , a relay node 2000 for processing an RRC message includes a control unit 2010 that establishes a signaling radio bearer or higher layer connection with a donor base station, and a receiver 2030 that receives an RRC message transmitted from the terminal and RRC and a transmitter 2020 for transmitting the message to a donor base station or another relay node using a signaling radio bearer or a higher layer protocol.

The control unit 2010 may establish a connection with the donor base station and set up a signaling radio bearer. Alternatively, the controller 2010 may establish a higher layer connection with the donor base station. For example, the upper layer connection may mean F3 Application Protocol (F3AP).

For example, the relay node 2000 refers to an integrated access and backhaul (IAB) node that is connected to a terminal through radio access and is connected to another relay node or a donor base station through wireless backhaul. Alternatively, the relay node 2000 may refer to an IAB node connected to another relay node or a donor base station through wireless backhaul. That is, here, the relay node 2000 may be an IAB node that performs direct connection with the terminal through radio access, or an IAB node that is not directly connected to the terminal by being located in the middle of the relay path or on the side of the donor base station.

The receiver 2030 may receive mapping information from a donor base station to establish a signaling radio bearer or higher layer connection. For example, the controller 2010 may establish a connection using mapping information between the logical channel identification information of the terminal and the backhaul RLC channel received from the donor base station. For the signaling radio bearer to be configured, ciphering is performed between the PDCP entity of the relay node 2000 and the PDCP entity of the donor base station.

In addition, the receiver 2030 receives the RRC message through radio access with the terminal.

The transmitter 2020 may transmit the donor base station's address information to the F3AP message including the RRC message in the adaptation entity of the relay node. Here, the address information of the donor base station may mean a GPRS Tunneling Protocol (GTP) tunnel endpoint identifier (TEID) received from the donor base station or an IP address of the donor base station.

In addition, the RRC message received from the terminal may be added to the payload of the F3AP message and transmitted through the signaling radio bearer. In addition to this, the F3AP message may further include at least one of terminal identification information and signaling radio bearer identification information.

Through this, the transmitter 2020 includes the RRC message of the terminal in the payload of the F3AP and transmits it to the donor base station through the signaling radio bearer. In addition, in order to transmit through the signaling radio bearer, the donor base station performs ciphering in the PDCP entity.

Also, the receiver 2030 may receive uplink user data from the terminal in a method of processing uplink user data.

The controller 2010 may derive a UE-bearer-ID by using logical channel identification information associated with an RLC PDU of uplink user data. For example, when uplink user data is received, the controller 2010 extracts a terminal bearer identifier by using logical channel identification information associated with the RLC PDU. That is, the controller 2010 may check the terminal bearer identifier by using the logical channel identification information.

The controller 2010 may select a backhaul RLC channel to transmit uplink user data based on at least one of a terminal bearer identifier and donor base station address information. For example, the controller 2010 may select a backhaul RLC channel mapped to the corresponding terminal bearer identifier by using the derived terminal bearer identifier. Alternatively, the controller 2010 may select a backhaul RLC channel through which uplink user data is to be transmitted using the donor base station address information. For example, the donor base station address information may be a GPRS Tunneling Protocol (GTP) tunnel endpoint identifier (TEID) received from the donor base station or an IP address of the donor base station. That is, the controller 2010 may receive and store donor base station address information in advance.

Meanwhile, the controller 2010 may select a backhaul RLC channel based on the backhaul RLC channel mapping information included in the terminal context setup message of the terminal received from the donor base station. That is, in order to select a backhaul RLC channel using at least one of the above-described terminal bearer identifier and donor base station address information, backhaul RLC channel mapping information is required. The receiver 2030 may receive backhaul RLC channel mapping information from the donor base station.

For example, the backhaul RLC channel mapping information may include N:1 (N is a natural number greater than or equal to 1) mapping information between at least one of a terminal bearer identifier and donor base station address information and a backhaul RLC channel. Alternatively, the backhaul RLC channel mapping information may include mapping information between the terminal bearer identifier and the donor base station address information.

Meanwhile, the backhaul RLC channel may be configured according to logical channel configuration information of the RRC message. That is, the controller 2010 may configure the backhaul RLC channel by using the logical channel configuration information of the RRC message.

The transmitter 2020 may transmit uplink user data to a donor base station or another relay node through the selected backhaul RLC channel. The transmitter 2020 transmits at least one of the terminal bearer identifier, the donor base station address information, the logical channel identification information, and the mapping information between the logical channel identification information and the backhaul RLC channel in the adaptation entity of the relay node to the uplink user data. can be transmitted including For example, when transmitting uplink user data through a backhaul RLC channel, the controller 2010 may additionally add terminal bearer identifier information to uplink user data. The operation of adding terminal bearer identifier information may be performed in the adaptation entity of the relay node. Alternatively, the donor base station address information and the above-described mapping information are additionally included in the transmitted uplink user data, so that the donor base station or other relay node can utilize the corresponding information.

Meanwhile, the receiver 2030 may receive an RRC connection request message from the terminal before receiving uplink user data from the terminal. Also, the transmitter 2020 may transmit the RRC connection request message to the donor base station through a signaling radio bearer or an F3AP message. It may further include the step of

In addition to this, the controller 2010 includes the RRC message of the terminal necessary for performing the above-described embodiment in the F3AP message and delivers it through the SRB, and backhaul RLC uplink user data of the terminal by using the logical channel identification information. Controls the overall operation of the relay node 2000 for transmission through the channel.

The transmitter 2020 and the receiver 2030 are used to transmit and receive signals, messages, and data necessary for carrying out the above-described present disclosure with the terminal, other relay nodes, and donor base stations.

The above-described embodiments may be supported by standard documents disclosed in at least one of IEEE 802, 3GPP and 3GPP2, which are wireless access systems. That is, steps, configurations, and parts not described in order to clearly reveal the technical idea of the present embodiments may be supported by the above-described standard documents. In addition, all terms disclosed in this specification can be explained by the standard documents disclosed above.

The above-described embodiments may be implemented through various means. For example, the present embodiments may be implemented by hardware, firmware, software, or a combination thereof.

In the case of implementation by hardware, the method according to the present embodiments may include one or more Application Specific Integrated Circuits (ASICs), Digital Signal Processors (DSPs), Digital Signal Processing Devices (DSPDs), Programmable Logic Devices (PLDs), FPGAs (Field Programmable Gate Arrays), may be implemented by a processor, controller, microcontroller, microprocessor, and the like.

In the case of implementation by firmware or software, the method according to the present embodiments may be implemented in the form of an apparatus, procedure, or function for performing the functions or operations described above. The software code may be stored in the memory unit and driven by the processor. The memory unit may be located inside or outside the processor, and may transmit and receive data to and from the processor by various known means.

In addition, the terms "system", "processor", "controller", "component", "module", "interface", "model", "unit", etc. as described above generally refer to computer-related entities hardware, hardware and software. may mean a combination, software, or software in execution. For example, the aforementioned component may be, but is not limited to being, a process run by a processor, a processor, a controller, a controlling processor, an object, a thread of execution, a program, and/or a computer. For example, both an application running on a controller or processor and a controller or processor can be a component. One or more components may reside within a process and/or thread of execution, and components may reside on one machine or be distributed across two or more machines.

The above description and the accompanying drawings are merely illustrative of the spirit of the present technology, and those of ordinary skill in the art may combine, separate, substitute and Various modifications and variations such as changes are possible. Therefore, the embodiments disclosed in the present specification are not intended to limit the present technical idea but to explain, and the scope of the present technical idea is not limited by these embodiments. The scope of protection of the present technical idea should be interpreted by the claims, and all technical ideas within the equivalent range should be interpreted as being included in the scope of the present specification.

Claims (20)

A method for a relay node to process uplink user data, the method comprising:
Receiving uplink user data from the terminal;
mapping the uplink user data to a GPRS Tunneling Protocol (GTP) tunnel;
determining a backhaul RLC channel to transmit the uplink user data; and
Transmitting the uplink user data to a donor base station or another relay node through the backhaul RLC channel,
The backhaul RLC channel is
It is determined based on the donor base station address information of the donor base station,
The donor base station address information,
Included in the terminal context setup message of the terminal received from the donor base station,
The transmitting step is
A method of transmitting donor base station address information in the uplink user data in the adaptation entity of the relay node. The method of claim 1,
The relay node is
An integrated access and backhaul (IAB) node connected to the terminal through radio access and connected to the other relay node or the donor base station through wireless backhaul. delete delete The method of claim 1,
The GTP tunnel and the backhaul RLC channel are
A method characterized in that N:1 (N is a natural number greater than or equal to 1) is mapped. delete delete delete delete delete In the relay node processing uplink user data,
a receiver for receiving uplink user data from the terminal;
mapping the uplink user data to a GPRS Tunneling Protocol (GTP) tunnel;
a control unit for determining a backhaul RLC channel through which the uplink user data is to be transmitted; and
A transmitter for transmitting the uplink user data to a donor base station or another relay node through the backhaul RLC channel,
The backhaul RLC channel is
It is determined based on the donor base station address information of the donor base station,
The donor base station address information,
Included in the terminal context setup message of the terminal received from the donor base station,
The transmitter is
A relay node for transmitting donor base station address information in the uplink user data in the adaptation entity of the relay node. 12. The method of claim 11,
The relay node is
The relay node, characterized in that it is an IAB (Integrated access and backhaul) node connected to the terminal through radio access and connected to the other relay node or the donor base station through wireless backhaul. delete delete 12. The method of claim 11,
The GTP tunnel and the backhaul RLC channel are
Relay node, characterized in that N:1 (N is a natural number greater than or equal to 1) is mapped. delete delete delete delete delete

Images