KR20190098693A - Methods for processing Uplink user data of relay node and Apparatuses thereof - Google Patents

Abstract

The present invention relates to methods for processing uplink user data of a relay node and apparatuses thereof, which are based on an integrated access and backhaul (IAB) using a 5G NR wireless communication technology. According to an embodiment of the present invention, in a method for a relay node to process uplink user data, the method for processing uplink user data of the relay node comprises: a step of receiving the uplink user data from a terminal; a step of using logic channel identification information associated with an RLC PDU of the uplink user data to induce a UE-bearer-ID; a step of selecting a backhaul RLC channel for transmitting the uplink user data based on one or more of the UE-bearer-ID and a donor base station address information; and a step of transmitting the uplink user data to the donor base station or another relay node via the selected backhaul RLC channel.

Description

Method for processing uplink user data of relay node and Apparatuses example}

 The present disclosure relates to an integrated access and backhaul (IAB) based data processing method and apparatus using 5G NR wireless communication technology.

In wireless communication systems, relay technology has been used to extend cell coverage using additional network nodes.

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

In other words, 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 of the configuration is indicated and configured through static OAM (Operations, administration and management). As a result, a plurality of hop relays could not be configured.

In addition, in the case of supporting the multi-hop relay through the conventional LTE technology, data cannot be divided and processed through a plurality of relay nodes, and signaling and data processing on the IP layer may increase delay.

In order to solve this problem, research on a technique 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 is to propose 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 proposes an RRC message processing method 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.

According to an embodiment of the present invention, in a method in which a relay node processes uplink user data, the method includes receiving uplink user data from a terminal and performing logical channel identification information associated with an RLC PDU of uplink user data. Deriving a UE bearer identifier (UE-bearer-ID), selecting a backhaul RLC channel for transmitting uplink user data based on at least one of the UE bearer identifier and donor base station address information, and selecting the selected backhaul RLC channel. It provides a method comprising the step of transmitting uplink user data to the donor base station or another relay node.

In addition, an embodiment of the present invention provides a relay node for processing uplink user data, comprising: a receiver for receiving uplink user data from a terminal and a terminal bearer identifier using logical channel identification information associated with an RLC PDU of uplink user data; A control unit for deriving a 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 donor uplink user data through a selected backhaul RLC channel Provided is 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, thereby providing an effect of effectively classifying and processing data according to terminal-specific or service-specific requirements.

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

1 is a diagram schematically illustrating a structure of an NR wireless communication system to which an embodiment of the present invention may be applied.
2 is a view for explaining a frame structure in an NR system to which the present embodiment can be applied.
3 is a diagram for describing a resource grid supported by a radio access technology to which the present embodiment can be applied.
FIG. 4 is a diagram for describing 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) illustrate a relay node start up procedure in a LTE technology.
9 is a diagram illustrating an RRC connection establishment procedure using a relay node according to an embodiment.
10 is a flowchart for describing an operation of relaying an RRC message by a relay node according to an embodiment.
11 is a diagram illustrating a protocol structure in which an RRC message is delivered according to an embodiment.
12 is a signal diagram illustrating a procedure of transmitting an RRC message to a base station according to an embodiment.
FIG. 13 is a flowchart illustrating an operation of transmitting uplink user data by a relay node according to an embodiment.
14 is a diagram illustrating a protocol structure for transmitting uplink user data according to an embodiment.
FIG. 15 is a diagram illustrating a protocol structure for transmitting uplink user data in a donor base station having a single structure according to an embodiment.
16 is a diagram illustrating a protocol structure in which uplink user data is delivered according to an embodiment.
17 is a diagram illustrating a protocol structure in which uplink user data is delivered according to an embodiment.
18 is a diagram illustrating a protocol structure in which uplink user data is delivered according to an embodiment.
19 is a diagram illustrating a protocol structure in which uplink user data is delivered 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 invention 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 shown in different drawings. In addition, in describing the technical idea, when it is determined that a detailed description of a related well-known configuration or function may obscure the gist of the present invention, the detailed description may be omitted.

In addition, in describing the components of the exemplary embodiments, terms such as first, second, A, B, (a), and (b) may be used. These terms are only to distinguish the components from other components, and the terms are not limited in nature, order, order, or number of the components. If a component is described as being "connected", "coupled" or "connected" to another component, that component may be directly connected to or connected to that other component, but between components It is to be understood that the elements may be "interposed" or each component may be "connected", "coupled" or "connected" through other components.

In addition, terms and technical names used in the present specification are for explaining a specific embodiment, and technical ideas are not limited to the terms. Unless otherwise defined, the terms described below may be interpreted as meanings generally understood by those skilled in the art to which the technical idea belongs. When the term is an incorrect technical term that does not accurately express the technical idea, it should be replaced with a technical term that can be understood by those skilled in the art. In addition, the general terms used herein should be interpreted as defined in the dictionary, or according to the context before and after, and should not be interpreted in an excessively reduced sense.

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

Meanwhile, the terminal in the present specification is a comprehensive concept of a device including a wireless communication module for communicating with a base station in a wireless communication system, and includes a UE in WCDMA, LTE, HSPA, and IMT-2020 (5G or New Radio). (User Equipment), of course, should be interpreted as a concept that includes a mobile station (MS), a user terminal (UT), a subscriber station (SS), a wireless device, and the like in GSM. In addition, the terminal may be a user portable device such as a smart phone according to a usage form, and may mean a vehicle, a device including a wireless communication module in a vehicle, and the like in a V2X communication system. In addition, in the case of a machine type communication (Machine Type Communication) system may mean an MTC terminal, an M2M terminal equipped with a communication module to perform machine type communication.

A base station or a cell of the present specification refers to an end point that communicates with a terminal in terms of a network, and includes a Node-B, an evolved Node-B, an eNB, a gNode-B, a Low Power Node, and an LPN. Sector, site, various types of antenna, base transceiver system (BTS), access point, access point (for example, transmission point, reception point, transmission point and reception point), relay node ), A mega cell, a macro cell, a micro cell, a pico cell, a femto cell, a remote radio head (RRH), a radio unit (RU), and a small cell.

Since the various cells listed above have a base station for controlling each cell, the base station may be interpreted in two meanings. 1) the device providing the mega cell, the macro cell, the micro cell, the pico cell, the femto cell, the small cell in relation to the wireless area, or 2) the wireless area itself. In 1) all devices that provide a given radio area are controlled by the same entity or interact with each other to cooperatively configure the radio area to the base station. According to the configuration of the wireless area, a point, a transmission point, a transmission point, a reception point, and the like become one embodiment of a base station. In 2), the base station may indicate the radio area itself that receives or transmits a signal from the viewpoint of the user terminal or the position of a neighboring base station.

In the present specification, a cell refers to a component carrier having a coverage of a signal transmitted from a transmission / reception point or a signal transmitted from a transmission point or a transmission / reception point, and the transmission / reception point itself. Can be.

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

The uplink and the downlink transmit and receive control information through a control channel such as a physical downlink control channel (PDCCH), a physical uplink control channel (PUCCH), a physical downlink shared channel (PDSCH), a physical uplink shared channel (PUSCH), and the like. Data is transmitted and received by configuring the same data channel. Hereinafter, a situation in which a signal is transmitted and received through a channel such as PUCCH, PUSCH, PDCCH, and PDSCH is described as 'transmit and receive PUCCH, PUSCH, PDCCH, and PDSCH'. do.

For clarity, the following description focuses on the 3GPP LTE / LTE-A / NR (New RAT) communication system, but the technical features are not limited thereto.

After researching 4G (4th-Generation) communication technology, 3GPP is conducting research on 5G (5th-Generation) communication technology to meet the requirements of ITU-R next generation wireless access technology. Specifically, 3GPP is conducting research on a new NR communication technology separate from LTE-A pro and 4G communication technology, in which LTE-Advanced technology is enhanced to meet the requirements of ITU-R as 5G communication technology. LTE-A pro and NR both appear to be submitted in 5G communication technology, but for the convenience of description, the following describes the embodiments of the present invention mainly on NR.

Operational scenarios in NR defined various operational scenarios by adding considerations to satellites, automobiles, and new verticals in the existing 4G LTE scenarios.In terms of services, they have eMBB (Enhanced Mobile Broadband) scenarios and high terminal density. Supports a range of mass machine communication (MMTC) scenarios that require low data rates and asynchronous connections, and Ultra Reliability and Low Latency (URLLC) scenarios that require high responsiveness and reliability and support high-speed mobility. .

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

<NR system general>

1 is a diagram schematically illustrating a structure of an NR system to which the present embodiment may be applied.

Referring to FIG. 1, an NR system is divided into a 5G core network (5GC) and an NR-RAN part, and the NG-RAN controls a user plane (SDAP / PDCP / RLC / MAC / PHY) and a user equipment (UE). It consists of gNB and ng-eNBs providing a 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. The 5GC may be configured to include an access and mobility management function (AMF) that is in charge of a control plane such as a terminal access and mobility control function, and a user plane function (UPF), which is in charge of a control function in user data. NR includes support for sub-6 GHz frequency bands (FR1, Frequency Range 1) and 6 GHz and higher frequency bands (FR2, Frequency Range 2).

gNB means a base station providing the NR user plane and control plane protocol termination to the terminal, ng-eNB means a base station providing the E-UTRA user plane and control plane protocol termination to the terminal. The base station described in the present specification should be understood to mean gNB and ng-eNB, and may be used to mean gNB or ng-eNB.

<NR Waveforms, Neutral and Frame Structures>

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

On the other hand, in NR, since the requirements for data rate, delay rate, and coverage are different for each of the three scenarios described above, it is necessary to efficiently satisfy the requirements for each scenario through a 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 neuron is determined based on sub-carrier spacing and cyclic prefix (CP), based on 15khz as shown in Table 1 below.

The value is used as an exponent value of 2 and is changed 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, the NR's pneumoroller may be classified into five types according to the subcarrier spacing. This is different from the fixed subcarrier spacing of LTE, which is one of 4G communication technologies, to be 15 kHz. Specifically, the subcarrier spacing used for data transmission in NR is 15, 30, 60, 120khz, and the subcarrier spacing used for synchronization signal transmission is 15, 30, 12, 240khz. In addition, the extended CP is applied only to the 60khz subcarrier interval. On the other hand, the frame structure (frame) in NR is a frame having a length of 10ms consisting of 10 subframes having the same length of 1ms is defined. One frame may be divided into half frames of 5 ms, and each half frame includes five subframes. In the case of a 15khz subcarrier interval, one subframe consists of one slot, and each slot consists of 14 OFDM symbols. 2 is a view for explaining a frame structure in an NR system to which the present embodiment can be applied.

Referring to FIG. 2, the slot is fixedly configured with 14 OFDM symbols in the case of a normal CP, but the length of the slot may vary depending on the subcarrier spacing. For example, in the case of a newerology with a 15khz subcarrier spacing, the slot has a length of 1 ms and the same length as the subframe. On the contrary, in the case of a numerology having a 30khz subcarrier spacing, the slot includes 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 with a fixed time length, the slot is defined by the number of symbols, the time length may vary according to the subcarrier interval.

Meanwhile, NR defines a basic unit of scheduling as a slot, and also introduces a mini slot (or subslot or non-slot based schedule) to reduce transmission delay of a radio section. The use of a wide subcarrier spacing shortens the length of one slot in inverse proportion, thereby reducing the transmission delay in the radio section. The mini slot (or sub slot) is for efficient support for the URLLC scenario and can be scheduled in units of 2, 4, and 7 symbols.

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

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

<NR Physical Resource>

With regard to physical resources in NR, antenna ports, resource grids, resource elements, resource blocks, bandwidth parts, etc. are considered Can be.

The antenna port is defined such that the channel on which the symbol is carried on the antenna port can be inferred from the channel on which another symbol on the same antenna port is carried. If the large-scale property of a channel carrying a symbol on one antenna port can be deduced from the channel carrying the symbol on another antenna port, then the two antenna ports are quasi co-located or QC / QCL. quasi co-location relationship. Here, the broad characteristics include one or more of delay spread, Doppler spread, frequency shift, average received power, and received timing.

3 is a diagram for describing a resource grid supported by a radio access technology to which the present embodiment can be applied.

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

The resource block is composed 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 shown in FIG. 3, one resource block may vary in size depending on the subcarrier spacing. In addition, the NR defines "Point A" serving as a common reference point for the resource block grid, a common resource block, a virtual resource block, and the like.

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

In NR, unlike LTE, where 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 the NR, as shown in FIG. 4, the bandwidth part can be designated within the carrier bandwidth and used by the terminal. In addition, the bandwidth part is associated with one neuralology and consists of a subset of consecutive common resource blocks and can be dynamically activated over time. The UE is configured with up to four bandwidth parts, respectively, uplink and downlink, and data is transmitted and received using the bandwidth part activated at a given time.

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

<NR initial connection>

In NR, the UE performs a cell search and random access procedure to access and communicate with a base station.

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

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, an SSB is composed of a primary synchronization signal (PSS) and a secondary synchronization signal (SSS), which occupy one symbol and 127 subcarriers, respectively, three OFDM symbols, and a PBCH spanning 240 subcarriers.

The terminal monitors the SSB in the time and frequency domain to receive the SSB.

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

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

On the other hand, 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 even where the center of the system band is not, and when supporting broadband operation, a plurality of SSBs may be transmitted in the frequency domain. Accordingly, the terminal monitors the SSB using a synchronization raster, which is a candidate frequency position for monitoring the SSB. The carrier raster and the synchronization raster, which are the center frequency position information of the channel for initial access, are newly defined in the NR, and the synchronization raster has a wider frequency interval than the carrier raster, and thus supports fast SSB search of the terminal. Can be.

The UE may acquire the MIB through the PBCH of the SSB. The Master Information Block (MIB) includes minimum information for the UE to receive the remaining system information (RMSI) that the network broadcasts. In addition, the PBCH is information about the position of the first DM-RS symbol in the time domain, information for the UE to monitor SIB1 (for example, SIB1 neuronological 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 neuronological information is equally applied to message 2 and message 4 of the random access procedure for accessing the base station after the terminal completes the cell search procedure.

The aforementioned RMSI means System Information Block 1 (SIB1), and SIB1 is broadcast periodically (ex, 160 ms) in a cell. SIB1 includes information necessary for the UE to perform an initial random access procedure and is periodically transmitted through the PDSCH. In order to receive the SIB1, the UE needs to receive the information of the neuterology used for the SIB1 transmission and the control resource set (CORESET) information used for the scheduling of the SIB1 through the PBCH. The UE checks scheduling information on SIB1 using SI-RNTI in CORESET and acquires SIB1 on PDSCH according to the scheduling information. The remaining SIBs other than SIB1 may be transmitted periodically or may be transmitted at 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, when the cell search is completed, the terminal transmits a random access preamble for random access to the base station. The random access preamble is transmitted on the PRACH. Specifically, the random access preamble is transmitted to the base station through a PRACH composed of consecutive 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 a UE performs 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 indicate to which UE 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, a Random Access-Radio Network Temporary Identifier (RA-RNTI).

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

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

In this 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). May be interpreted as meaning used in the past or present, or various meanings used in the future.

LTE relay technology

In LTE technology, relay technology has been used for the purpose of extending cell coverage through the use of an additional network node called a relay node (RN). The LTE RN relays user plane data and control plane data at the IP packet level. In addition, a service is provided only through a single RN between a donor base station (Denor eNB, DeNB) serving a relay node and a terminal. 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 data of the terminal 700 to the gateway 730. The terminal 700 includes an L1 physical layer and an L2 layer, IP, TCP / UDP, App. It is organized in 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.

FIG. 8 is a diagram illustrating a relay node start-up procedure in LTE technology.

In the LTE relay technology, the RN startup procedure of FIGS. 8A and 8B for initiating RN operation is used to configure the necessary parameters for the RN.

8 (A) and 8 (B), after the RN 800 is powered on (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 serving the RN 800, the RN 800 needs to identify which cell supports the RN 800 operation. If the RN 800 already knows accessible cells, phase I may be omitted and phase II may be performed immediately.

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

Phase I: Attach for RN preconfiguration.

The RN 800 connects to the E-UTRAN / EPC as a terminal at power up (S815), and retrieves an initial configuration parameter including a list of DeNB cells from the RN OAM 850 (S825). After the operation S825 is completed, the RN 800 disconnects from the network as a terminal (S835) and triggers Phase II described below. The MME 820 performs S-GW and P-GW 830 selection 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 relaying operation (S806).

 When DeNB 810 starts to establish bearer for S1 / X2, RN 800 starts to establish S1 and X2 connections with DeNB 810. In addition, the DeNB 810 initiates an RN reconfiguration procedure through RRC signaling for an RN specific parameter (S807). (The RN connects to a DeNB selected from the list acquired during Phase 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.)

The DeNB 810 performs an S1 eNB configuration update procedure when the configuration data is updated to the RN connection after performing S1 setup with the RN 800 (S808) (S809). In addition, after performing the X2 setup with the RN 800 (S811), the DeNB 810 updates the 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 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 such, since the RN of the conventional LTE relay technology supports only a single hop relay, the configuration of the relay is mostly provided through a static OAM. From the perspective of the terminal, the RN acts as a base station, and the RN recognizes the donor base station as a core network entity and forms a terminal context in the RN. Therefore, the RN is configured by indicating most of the configuration through the static OAM, and only the radio configuration (for example, the RN subframe configuration) specific to the entire RN device has been indicated and configured 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 the service requirements for each terminal. If there is a desire to support a multi-hop relay through the conventional LTE technology, there is a problem in that there is no method for processing data separately through a plurality of relay nodes. In addition, signaling and data processing on the upper IP layer has a problem that can increase the delay.

High layer functionalsplit

Next-generation wireless access networks (hereinafter referred to as NR or 5G or NG-RAN for ease of explanation) are distributed with centralized nodes (hereafter referred to as central units (CUs) for ease of explanation) to support efficient network deployment. Nodes (hereinafter referred to as DUs (Distributed Units for convenience)) may be provided separately. That is, the base station may be configured divided into CU and DU in a logical or physical aspect. In the present disclosure, the base station is a base station to which the NR technology is applied and may be referred to as gNB 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 logical nodes hosting RRC, SDAP and PDCP protocols. Alternatively, CU means a logical node hosting RRC and upper layer L2 protocol (PDCP). The 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 means a logical node hosting the RLC, MAC and PHY layers. The operation of the DU is partly 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 connected to 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.) Connected to a 5G Core network (5GC) via an NG interface.

The 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). . CU and DU are connected via F1 interface. (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 such, the F1 interface is an interface providing an interconnection between the CU and the DU, and the F1AP (The F1 Application Protocol) is used to provide a signaling procedure on the interface.

For EN-DC, the S1-U interface and X2-C interface for one base station consisting 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.) The DU connected to the CU is visible to other base stations and the 5GC as only one base station (The gNB-CU and connected gNB-DUs are only visible to other gNBs and the 5GC as a gNB).

NR (New Radio) based relay

3GPP is working on the initial specification for 5G wireless communication technology (NR) to meet various requirements of technological development. In NR, which can use high frequency bands, the use of relay technology can be increased due to the higher bandwidth and use of multi-beam systems compared to LTE. This makes it easier for operators to build a dense network of self-backhauled NR cells that provide their own backhaul function. However, millimeter wave bands can have the disadvantage of experiencing severe short-term blocking. In addition, small coverage and beam operations in the millimeter wave band may need to be connected to base stations connected to wired / fiber via multi-hop relays. In this case, the terminal cannot be connected to a base station connected to a wired / optical line by using a relay technology according to the conventional LTE technology. In particular, as multi-hop relays must process data in multi-hop, it can be difficult to use for delay-sensitive 5G service transmission. Accordingly, research on various protocol structures for satisfying service quality in multi-hop is necessary, but no specific technology has been presented.

Accordingly, the present disclosure proposes an NR relay structure that can effectively divide data into quality requirements for each terminal or service by configuring a plurality of hop relays. In addition, under the NR relay structure, a specific procedure and apparatus for connecting a terminal to a base station through a multi-hop relay node are proposed.

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

The donor base station herein refers to a radio network node (or base station or gNB or part of gNB) that terminates an interface to a core network (NG interface (eg, N2, N3 interface)). 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 a base station, a CU, a DU, a core network node (AMF, UPF, etc.) using an NR radio technology. The donor base station may be composed of one CU and one or more DUs in the same manner as the NR base station. The donor base station may be replaced with 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. IAB nodes can configure backhaul to other NR nodes using NR radio technology. In addition, IAB nodes are not physically connected to other NR nodes via wired / optical lines. The IAB node may be replaced with various terms such as a relay node, an NR-RN, an NR relay, or an integrated node. Hereinafter, the description will be given 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 can be replaced by various terms such as an IAB backhaul interface, a U-IAB interface, and a Ui interface.

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

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

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

The prober described with reference to FIG. 9 may be applied to various protocol structures described below. In FIG. 9, for convenience of explanation, the terminal and the donor base station transmit and receive data through two hops (eg, IAB 1 and IAB 2). This is for convenience of description only, and may be equally applicable to any IAB node number.

Referring to FIG. 9, the donor base station 903 performs a connection setup operation with the IAB nodes IAB 2 and 902 directly connected through the air 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 the IAB 1 901, and initiates a random access operation to the IAB 1 901 (S920). The IAB 1 901 transmits a response to the random access preamble in the random access response message to the terminal 900 (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 connected to the terminal 900 or the IAB 1 901 or the IAB 2 902 on the backhaul interface between the IAB 2 902 and the donor base station 903 through an RRC connection reconfiguration procedure with the IAB 2 902. A signaling radio bearer for control message transmission is configured (S935). Also, the donor base station 903 transmits a control message of the terminal 900 or the IAB 1 901 on the interface of the IAB 1 901 and the donor base station 903 through an RRC connection reconfiguration procedure with the IAB 1 901. A signaling radio bearer is configured (S940).

The donor base station 903 transmits an RRC connection setup message to the terminal 900 to set up an RRC connection 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 an RRC connection setup complete message through the IAB 1 901 and / or the IAB 2 902. In step 903, the process transmits to step 903.

When the donor base station 903 completes the RRC connection setup with the terminal 900, the donor base station 903 performs signaling with the core network entity (S955). Through this, the PDU session ID, the S-NSSAI, the QFI (QoS flow indicator), and the QoS profile associated with the QFI to be configured in the terminal 900 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 the IAB 1 901, the IAB 2 902, and the terminal 900 (S965 and S970). The donor base station 903 transmits an RRC connection reconfiguration message to configure a radio resource in the terminal 900 (S970). The terminal 900 transmits an RRC connection reconfiguration complete message to notify confirmation of the radio resource configuration (S975).

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

Hereinafter, each step described in FIG. 9 will be described in detail by dividing step by step.

1) Connection setup of IAB node (IAB 2) directly connected to donor base station via air interface

If the IAB node is directly connected to the donor base station through an air 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 cell, the IAB node may establish an RRC connection to the donor base station to perform network registration. The IAB node may extract an initial configuration parameter containing a donor base station cell list from the (IAB) OAM for preconfiguration of the IAB node. Thereafter, for the IAB operation, the IAB node may select a cell having the best radio quality among the cells included in the donor base station cell list, establish an RRC connection through the cell, and perform IAB node operation.

For example, the IAB node and the cells of the IAB node may be configured by the IAB OAM. The cell configuration of the IAB node and the IAB node may be performed together when extracting an initial configuration parameter including a donor base station cell list from the IAB OAM, or may be performed in a phase II process of performing network registration as an IAB node. Or may be preconfigured in an IAB node.

As another example, radio resource configuration for the IAB node and the cells of the IAB node may be indicated and configured by the donor base station. The radio resource configuration operation may be performed in phase I when 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 a multi-hop topology, the donor base station may control the radio resource of the IAB node for efficient radio resource control. As a result, when the terminal accesses the donor base station and transmits and receives data, the IAB nodes can effectively classify / process user data traffic between the terminal and the donor base station according to QoS parameters.

As another example, the IAB node sends an interface setup request message between the IAB node and the donor base station to the donor base station. For convenience of explanation, the interface between the IAB node and the donor base station is 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 a terminal and a donor base station. If the donor base station is divided into a CU and a DU, the F3 interface may represent an interface between an access IAB node serving a terminal and a donor base station DU, or an interface between an access IAB node serving a terminal and a donor base station CU.

Similar to the F1AP (F1 Application Protocol) of the F1 interface, which is an interface between the CU and the DU, a higher layer protocol may be provided to provide a signaling procedure between a donor base station and an IAB node on the F3 interface. It is written as (F3 Application Protocol). For example, the interface setup request message between the IAB node and the donor base station described above represents an F3AP message used for exchanging application level data necessary for the IAB node and the donor base station to operate correctly on the F3 interface.

The F3 interface setup request message includes a cell list configured in the IAB node. Alternatively, the F3 interface setup request message may include a cell list configured at the IAB node and ready to be activated, or a candidate cell list that may 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 an NG setup or gNB configuration update procedure with a 5G core network (5GC).

The donor base station sends 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 configure in the IAB node. Alternatively, the F3 interface setup response message may include a cell list to be activated among the cell list or candidate cell list to be activated in the IAB node. 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 the cells become operational.

2) connection setup of an IAB node (IAB 1) connected via a radio interface provided by another IAB node (ex, IAB 2)

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

For example, in order to preconfigure 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 the cell list of another IAB node, except for the donor base station cell list, from the IAB OAM. Alternatively, the IAB node may be a donor base station cell list from the IAB OAM, a cell list of another IAB node, an active cell list of another IAB node, a cell list of adjacent IAB nodes, an active cell list of adjacent IAB nodes, 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 an IAB node may be extracted.

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

As another example, the donor base station may indicate / configure preconfiguration information or configuration information of the IAB node connected to the donor base station through another IAB node to the IAB node through an RRC message. For example, the preconfiguration information or configuration information may be a donor base station cell list, a cell list of another IAB node, an active cell list of another IAB node, a cell list of an adjacent IAB node, an active cell list of an adjacent IAB node, a neighbor IAB. At least one of a cell list of a node, a neighbor cell list, and a neighbor cell list associated with an IAB node may be included. The aforementioned RRC message may be included in an RRC connection release message or an RRC connection reconfiguration message. The donor base station may release the RRC connection of the IAB node. Subsequently, for an IAB operation, the IAB node (or terminal) may select a cell having the best radio quality among the cells included in the received cell list, establish an RRC connection through the corresponding cell, and perform an IAB node operation.

If the IAB node performs the same cell selection / reselection operation as the IDLE mode general terminal, it is likely to select / reselect the cell with the best radio quality or to select / reselect the cell with the highest 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.

For example, in selecting / reselecting a cell included in the received cell list, the IAB node may select / reselect in consideration of whether the donor base station is provided by each cell or the number of hops to the donor base station. Specifically, when the IAB node performs an operation for cell selection / reselection, information or donor for indicating whether the cell is a cell provided by the donor base station to a cell selection criterion (or cell reselection criterion / cell ranking criterion). One or more of adjustment parameters / offsets / scaling values depending on the number of hops to the base station may be included (added or subtracted). The parameter additionally applied to the above-described cell selection criteria may be applied to one of the following cell selection / cell reselection criteria parameters.

The following equation shows an example of the 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 refers to the values in the table below, and Qoffset _temp refers to offset parameters that can be applied as needed. Parameters additionally applied according to the present disclosure may be subtracted or added in each of the above-described equations.

Meanwhile, the above-described donor base station cell list, a cell list of another IAB node, a parameter for cell selection / cell reselection of an IAB node (for example, information indicating whether or not the cell is provided by the donor base station, up to the donor base station) One or more of information for indicating the number of connection hops, additional parameters) and 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 with an IAB node.

Alternatively, the above-described donor base station cell list, a cell list of another IAB node, a parameter for cell selection / cell reselection of the IAB node (for example, information 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 the NR, broadcasted at a fixed period, the system is divided into other system information (RMSI) rather than the minimum system information and the minimum system information that the terminal can always receive. The minimum system information is broadcast in a fixed period and includes basic information required for initial access, and is divided into a master information block transmitted on a BCH and a system information block type 1 transmitted on a DL-SCH. Can be. On the other hand, other system information (RMSI) is provided with a period and scheduling information that is 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) on-deamand based on the minimum system information. For example, other system information may be received in the process of performing random access. For example, other system information may be received during the RRC connection setup process.

Alternatively, the above-described donor base station cell list, a cell list of another IAB node, a parameter for cell selection / cell reselection of the IAB node (for example, information indicating whether the cell is provided by the donor base station, up to the donor base station) One or more of information for indicating the number of connection hops, additional parameters) and 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.

Alternatively, the above-described donor base station cell list, a cell list of another IAB node, a parameter for cell selection / cell reselection of the IAB node (for example, information indicating whether the cell is provided by the donor base station, up to the donor base station) One or more of information for indicating the number of connection hops, additional parameters) and initial configuration parameters of the IAB node may be transmitted by the donor base station to the IAB node through an F3AP message.

In addition, the above-described donor base station cell list, cell list of other IAB nodes, and cell selection / cell reselection of IAB nodes may be used when the IAB node experiences a radio link failure (for example, when the connected IAB node is a higher IAB node). Detecting a failure in the radio link to the node), an IAB node may be used to perform cell selection / reselection / link selection for connection recovery to the donor base station. For example, if an IAB node detects a radio link failure, the IAB node reestablishes the connection to the donor base station through another cell. This procedure may be provided through a general cell selection procedure or may perform cell selection among cells provided via an alternate path pre-configured by the donor base station. The donor base station may configure information on the IAB node to perform reconfiguration first to support fast recovery when any IAB node detects a radio link failure through an RRC dedicated message. The information includes one or more of priority cells, priority cell lists, priority frequencies, reset candidate cells, reset candidate cell lists, donor base station cell lists, cell lists of other IAB nodes, and connection hops to donor base stations per cell. It may include. If the IAB node detects a radio link failure to the donor base station or higher IAB node, it reestablishes the connection to the donor base station using the corresponding information. For example, the IAB node may perform cell selection with priority 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 the broadcast system information. When the radio link of an IAB node is reestablished, the number of connection hops to the donor base station of another IAB node connected to the IAB node changes. The donor base station transmits information for modifying the number of connection hops to each donor base station of each IAB node or a cell accommodated by each IAB node to each IAB node, and the corresponding IAB node receives the information and stores the changed information. The information may be indicated from the donor base station to the IAB node through an RRC message or an F3AP message.

Meanwhile, the terminal may also perform cell selection / cell reselection by prioritizing 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. 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 terminal attempts to access the network (for example, triggers transmission of outgoing data from the IDLE terminal), the terminal is an IAB 1 node. Initiate a random access procedure. The MAC entity of the terminal transmits the random access preamble to the IAB 1 node. That is, the terminal recognizes the IAB 1 node as a base station and transmits a random access preamble.

4) Random access response

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

5) Send RRC connection request message

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

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

For example, the IAB 1 node may transmit an RRC connection request message by including the uplink RRC message. As another example, the IAB 1 node may send 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 uplink RRC message transmission. As another example, the F3AP message transmitted by the IAB 1 node to the donor base station through the F3 interface may include information on at least one of a terminal identifier and signaling bearer type (eg SRB0, SRB 1, SRB2) in addition to the RRC connection request message. . For example, the message transmitted by the IAB 1 node to the donor base station may include the C-RNTI. Or, the terminal identifier is a valid C-RNTI transmitted by the terminal to the IAB 1 node, RA-RNTI included when the terminal transmits a random access preamble for contention-based random access, and Temporary C assigned by the IAB 1 through a random access response message. -RNTI, IAB 1 may be one or more of the RA-RNTI information and the C-RNTI of the terminal confirmed through the random access response message. Through this, the donor base station may acquire the C-RNTI assigned by the access IAB node of the terminal, and uniquely identify the terminal together with IAB node information and / or cell identification information to perform radio resource control. For another example, the terminal identifier may be an I-RNTI allocated by the IAB1 node. The I-RNTI may uniquely identify a terminal context of the corresponding terminal as identification information for identifying the inactive state terminal. For another example, the IAB 1 node may transmit a new terminal identifier (denoted as IAB-RNTI for convenience of description) to uniquely identify the terminal accommodated at the donor base station to the donor base station. The donor base station may uniquely identify the terminal through the IAB-RNTI and the IAB node information. For another example, the message transmitted by the IAB 1 node to the donor base station may include an IAB UE F3AP ID for uniquely identifying the terminal association through the F3 interface.

In a contention-based random access, since a terminal selects a random access preamble by itself, there is a possibility that more than one terminal simultaneously transmits 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 additional contention resolution steps are required. To this end, the IAB node or the donor base station may indicate to the terminal which transmission of the terminal is actually received.

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

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

For example, the IAB 1 node stores / buffers / stores / maintains an RRC connection request message (CCCH SDU) until an RRC connection setup message is received from a donor base station.

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

As another example, the donor base station stores the C-RNTI of the terminal as a temporary C-RNTI as a terminal context. After receiving the RRC connection setup complete message from the terminal sets the value of the temporary C-RNTI to C-RNTI.

As another example for this purpose, the IAB 1 node stores / buffers / stores / maintains the C-RNTI received from the UE. After receiving the RRC connection setup message from the donor base station sets the value of the temporary C-RNTI to C-RNTI. Or, when receiving the RRC connection setup complete message from the terminal, sets the value of the temporary C-RNTI to C-RNTI.

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

The donor base station may configure SRB1 for the terminal that has transmitted the RRC connection request message to the IAB 1 node / IAB 2 node and 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 necessary configuration information in the IAB1 node / IAB2 node to the IAB 1 node / IAB 2 node. For example, the configuration information may include mapping information for mapping and transmitting signaling radio bearer data of each terminal to a radio bearer / RLC bearer between interfaces.

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 UE and the F3AP message of the IAB 1 node to the IAB 1 node, which is the access IAB node of the UE, and then the RRC message of the UE 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, the access IAB node of the IAB 1 node, through the corresponding signaling radio bearer. 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 transmits an RRC message or an F3AP message including mapping information for transmitting the RRC message of the terminal to the SRB1 between the IAB 1 node and the donor base station to the IAB 1 node which is the access IAB node of the terminal. Can be sent via As another example, the donor base station may include an RRC including mapping information between an incoming RLC channel including an RRC message of a terminal received from a corresponding IAB 1 node and an outgoing RLC channel transmitted to a donor base station to an IAB 2 node that is an access IAB node of an IAB 1 node. Message or F3AP message can be sent. Through this, the RRC message of each terminal may be transmitted by being distinguished 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) RRC connection setup message transmission from donor base station to terminal

The donor base station transmits an RRC connection setup message to the terminal through the IAB2 node and the IAB1 node. The RRC connection setup message transmitted from 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) UE sends RRC connection setup complete message to donor base station through IAB node 1

If the CCCH SDU is included in the MSG3 and the PDCCH transmission is addressed by the UE's temporary C-RNTI, if the MAC PDU is successfully decoded, the UE if the UE contention resolution identity in the MAC CE matches the CCCH SDU sent to the MSG3 Consider that competition is successful. The terminal 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 sent 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 complete message may be included in the F3AP message and transmitted through the SRB.

On the other hand, when the terminal identifier is used as C-RNTI (16 bits), there is a very low possibility of collision. 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 the possibility that a C-RNTI that is duplicated / collided / contended in cells provided by multiple IAB nodes housed in a donor base station is used. The node identifier may be used together with the terminal identifier assigned by the C-RNTI or IAB 1 node as the terminal identifier so that collision does not occur. The node identifier may be assigned when the IAB node establishes a connection setup / access to the donor node. The node identifier may be assigned to the IAB node at the donor base station via the RRC message.

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

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

10) Core Network Signaling

The donor base station performs signaling with the core network entity when the RRC connection establishment with the terminal is completed. For example, the donor base station sends an NGAP initial UE message to the core network through an NG interface between the base station and the AMF to receive an initial terminal context setup message, and establishes a terminal context. Perform the procedure. Through this, the PDU session ID, the S-NSSAI, the QFI (QoS flow indicator), and the QoS profile associated with the QFI to be configured in the terminal 900 are received from the core network entity. It can be used with any of the signaling messages described in the 3GPP TS 38.413 NGAP protocol.

11 ~ 12) Data radio bearer configuration for corresponding terminal in IAB 1 node / IAB 2 node

When the donor base station configures a data radio bearer (DRB) with a terminal and transmits and receives data, the donor base station may configure configuration information required by the IAB 1 node / IAB 2 node 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 with 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 transmitting data for each data radio bearer of each terminal by mapping the data to the radio bearer / RLC bearer between interfaces. For example, it may include mapping information for transmitting data for each data radio bearer of each terminal to an interface between an IAB 1 node and an IAB 2 node and an interface between an IAB 2 node and a donor base station. The information may be indicated to the IAB node through an F3AP message between the donor base station and the IAB node.

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

13 ~ 14) Radio resource configuration to UE through RRC connection reconfiguration procedure

The donor base station configures a radio resource (such as a radio bearer configuration) in the terminal through an RRC connection reconfiguration message. The terminal sends a confirmation message about this.

As described above, the terminal and the IAB nodes donor base station establishes a connection through a relay operation, and transmits and receives an RRC message.

Hereinafter, the operation of the relay node (IAB node) for transmitting the RRC message of the terminal to the donor base station in more detail. For example, the RRC message transmitted by the terminal may be delivered to the donor base station through a signaling radio bearer, and may be delivered in an F3AP message. In the present embodiment, a description will be made of the uplink RRC message, but may also be applied to the downlink RRC message. In addition, the relay node below describes the above-described IAB node by way of example, but is not limited thereto.

10 is a flowchart for describing an operation of relaying an RRC message by a relay node according to an embodiment.

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

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

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

In the signaling radio bearer configured, ciphering is performed in 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 an RRC message through radio access with the terminal.

The relay node may perform the step of transmitting the RRC message to a 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 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 Tunnelling Protocol (GTP) Tunnel Endpoint Identifier (TEID) or a donor base station IP address received from 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, the F3AP message may further include at least one of terminal identification information and signaling radio bearer identification information.

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

11 is a diagram illustrating a protocol structure in which an RRC message is delivered according to an embodiment.

Referring to FIG. 11, the donor base station 1130 assumes a separation structure between a CU and a DU, but may be applied even when the separation structure is not. That is, the structure of the donor base station 1130 is not limited.

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

If necessary, the IAB 2 1110 and the IAB 1 1120 classify the RRC message transmitted including the Adaptation entity. The RRC message is included in the payload of the F3AP message and can be delivered through the SRB.

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

IAB nodes may be divided into MT parts and DU parts, and the MT part may be recognized as a function similar to a terminal in terms of a donor base station or an connected IAB node. The DU part is recognized as a function similar to a DU base station in terms of a terminal or an 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 1231, and the 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).

The IAB 1 1210 DU part receives payload 1 transmitted from the IAB 2 1200 MT part. Payload 1 represents a PDCP PDU containing 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 further includes IAB 2 1200 F3AP UE ID and Adaptation layer information. Payload 2 of 1241 includes PDCP, F3AP, Payload 1.

DU 1221 of donor base station 1220 learns a particular message type (F3AP message of IAB node). Then remove the header of the adaptation layer and encapsulate payload 2 (including the I3 node's F3AP message) in its own F1AP message (S1245) (Donor-DU learns the specific message type (F3AP message of IAB-node). 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 includes a F1AP message (eg, DL IAB F1AP) that includes routing information for payload 2 and payload 2 (eg, IAB 1 address, donor base station CU address, etc.). (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).

DU 1221 of donor base station 1220 extracts payload 2 from the received F1AP message (eg, DL IAB F1AP message) and adds an adaptation layer header containing the necessary 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).

The DU 1221 of the donor base station 1220 transmits an encapsulated downlink F3AP message (transmission of a DL RRC message inside payload 2) as an IAB 1 1210 MT part through an 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 from an IAB node) according to a specific SRB or message type indicator, and confirms that the F3AP message is for itself with routing information in the adaptation header. . Thereafter, the IAB 1 1210 MT part removes the header of the adaptation layer and delivers an F3AP message including an RRC message for the IAB 2 1200 after the receiver processing of the PDCP layer 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.The IAB-node 1 DU part extracts the RRC message from F3-AP message).

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

As described above, the relay node transmits the RRC message to the donor base station through the SRB by including the RRC message in the F3AP message.

Hereinafter, a protocol structure of a relay node supporting the above-described operation will be described. For convenience of explanation, hereinafter, the user plane protocol structure will be described through an uplink data transmission operation. This is just for convenience of explanation, and the same method may be applied to the control plane protocol structure. In addition, the following describes a protocol structure through two hops, but a structure through a hop set to any number is included in the scope of the present disclosure.

FIG. 13 is a flowchart illustrating an operation of transmitting uplink user data by a relay node according to an embodiment.

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

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

The relay node may perform a step of selecting 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 (S1320). For example, the relay node may select a backhaul RLC channel mapped to the corresponding UE bearer identifier using the derived UE bearer identifier. Alternatively, the relay node may select a backhaul RLC channel to transmit uplink user data using donor base station address information. For example, the donor base station address information may be a GPRS Tunnelling Protocol (GTP) Tunnel endpoint identifier (TEID) or a donor base station IP address received from 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, backhaul RLC channel mapping information is required to select a backhaul RLC channel using at least one of the above-described terminal bearer identifier and donor base station address information. 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 of 1 or more) mapping information between at least one of the terminal bearer identifier and the donor base station address information and the 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 the logical channel configuration information of the RRC message. That is, the relay node may configure the backhaul RLC channel using the logical channel configuration information of the RRC message.

The relay node may perform the step of transmitting uplink user data to the donor base station or another relay node through the selected backhaul RLC channel (S1330). The relay node may transmit information including at least one of terminal bearer identifier, donor base station address information, logical channel identification information, and mapping information between logical channel identification information and backhaul RLC channel in uplink user data in the adaptation entity of the relay node. . For example, in transmitting the uplink user data through the backhaul RLC channel, the relay node may add UE bearer identifier information to the uplink user data. Adding the 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 may be additionally included in the uplink user data transmitted, so that the donor base station or another relay node may use the corresponding information.

Meanwhile, the relay node further includes receiving an RRC connection request message from the terminal and transmitting the RRC connection request message to the donor base station through a signaling radio bearer or an F3AP message before receiving the uplink user data from the terminal. can do. As described with reference to FIGS. 10 to 12, the relay node may include the RRC message of the UE in the F3AP message and transmit the same 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 may process the uplink user data by 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 transmit corresponding uplink user data and transmits it through the selected backhaul RLC channel.

Hereinafter, various examples of the aforementioned protocol for transmitting uplink user data will be described with reference to the accompanying drawings. For convenience of explanation, hereinafter, a relay node will be described as an IAB node.

14 is a diagram illustrating a protocol structure for transmitting uplink user data according to an embodiment.

Referring to FIG. 14, the IAB 2 1410 receives uplink user data through the DRB from the UE 1400. The IAB 2 1410 derives the UE bearer identifier by 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 to transmit uplink user data based on at least one of a terminal bearer identifier and donor base station address information.

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

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

FIG. 15 is a diagram illustrating a protocol structure for transmitting uplink user data in a donor base station having a single structure according to an embodiment.

Referring to FIG. 15, the protocol structure of FIG. 14 is the same as that of the terminal 1400, the IAB 2 1410, and the IAB 1 1420. 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. In addition, the transmission path and operation of uplink user data are the same as in FIG.

An embodiment of a protocol structure for performing L3 forwarding at an IAB node

16 is a diagram illustrating a protocol structure in which uplink user data is delivered according to an embodiment.

Referring to FIG. 16, (each) IAB nodes 1610 and 1620 may forward user data at L3 (IP layer) similar 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 should support not only the layer 2 function but also the higher layer functions of the layer 3 or more. For example, the IAB 1 1610 may configure / reconfigure a radio connection parameter to the terminal 1600 through an RRC connection reconfiguration message to the terminal 1600. In this manner, the IAB 1 1610 supporting the layer 3 may control a cell having a cell identifier owned by it, and may make the terminal 1600 look like a normal base station. However, in this case, in processing user data, there is a problem in that a delay for processing an IP packet may be increased in addition to the layer 2 processing.

User data forwarding between IAB nodes (ex, between IAB 1 and IAB 2) is done via the GTP-U (or GTP-U / UDP / IP, or GTP-C, GTP / SCTP protocol if control plane data) protocols. Can be. Through this, it may be possible to process traffic that is differentiated / differentiated for each radio bearer per user (or per flow). For example, the IAB nodes 1610 and 1620 may distinguish this 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. Typically, the GTP-TEID is an information for unambiguously identifying the tunnel endpoint at the receiving GTP-U protocol entity and locally assigns a TEID to be used by the transmitting side at the receiving side of the GTP tunnel. At 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 the user data which becomes 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 transmit the TEID to the access IAB node serving the terminal along with the donor base station IP address. In this case, the TEID and the IP address may be delivered through an RRC message or an F3AP message.

As another example, the IAB nodes 1610 and 1620 may include 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 SRB type can be distinguished through the mapping information for one or more. For example, the IAB nodes 1610 and 1620 may receive the uplink user data associated with the PDU session ID and the QFI of the corresponding terminal from the terminal 1600, map them to the GTP-TEID, and transmit them to the donor base station.

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

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

An embodiment of a protocol structure for performing L3 forwarding at a first hop IAB node connected to a terminal and performing L2 forwarding at another IAB node

17 is a diagram illustrating a protocol structure in which uplink user data is delivered according to an embodiment.

Referring to FIG. 17, the first hop IAB node 1710 constituting a direct wireless connection with the terminal 1600 may allow user data to be forwarded in L3 (IP layer) similarly to the conventional LTE RN. To this end, the first hop IAB nodes IAB 1 and 1710 having a direct wireless connection with the terminal 1600 should support not only the layer 2 function but also the higher layer functions of the layer 3 or more. 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 the layer 3 may control a cell having a cell identifier owned by it, and may make the terminal 1600 look like a normal base station. However, in this case, there is a problem in that a delay for processing an IP packet may be increased in addition to the 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 the control plane data, GTP-C, GTP User data can be transferred via the protocol. For example, the first hop IAB node 1710 and the donor base station 1730 having a direct wireless connection with the terminal 1600 may process traffic classified by user (or flow) by radio bearer per user through GTP TEID. May be possible. In another example, the IAB node 1710 and the donor base station 1730 may include a GTP TEID, a transport layer address (eg, a donor base station IP address), a PDU session ID, an S-NSSAI, a QoS flow indicator (QFI), an associated QoS profile, Traffic per user radio bearer can be distinguished through mapping information on one or more of DSCP, drb-identity and SRB type. For example, the first hop IAB node 1710 receives the uplink user data associated with the PDU session ID and the QFI of the corresponding terminal from the terminal 1600 and maps it to the GTP-TEID and the donor base station IP address to classify the donor base station. Can transmit As another example, when the first hop IAB node 1710 classifies 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. And uplink user data associated with the logical channel identification information mapped to the QFI or the terminal bearer identifier, may be transmitted to the donor base station by mapping it to the GTP-TEID and the donor base station IP address.

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 based on L2. 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 is processed with the corresponding data through a corresponding QoS parameter / profile (e.g., one or more 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 the 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 the data for each terminal, the terminal identifier for the terminal-specific classification may be added and transmitted in the transmitting SDAP entity or the adaptation layer entity above the SDAP. The IAB 2 node 1720 may select a flow / data mapped based on the added terminal identifier. The receiving SDAP entity or the adaptation layer entity higher than the SDAP may remove the terminal identifier for distinguishing the terminal and transmit the terminal identifier to the higher layer.

Alternatively, the IAB 2 node 1720 of FIG. 17 may operate without the SDAP layer. That is, the IAB 2 node 1720 may forward user data in the PDCP layer. Through this, data forwarding for distinguishing a radio bearer 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 distinguished for each terminal, the terminal may be transmitted by adding a terminal identifier for distinguishing between terminals in the transmitting SDAP entity or the adaptation layer entity between the SDAP and the PDCP entity or the PDCP entity. In step 1720, the radio bearer is selected based on this, and the terminal identifier for the terminal-specific identification 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 the SDAP layer and the PDCP layer. The user data may be forwarded on an adaptation layer or an RLC layer or an RLC layer or an RLC layer and an MAC layer on the MAC layer. Through this, data forwarding for distinguishing a radio bearer / RLC bearer / logical channel may be performed. However, since the IAB 2 node 1720 cannot be distinguished for each terminal, the terminal bearer identifier for the terminal-specific identification in the adaptation layer entity or RLC layer entity on the transmitting RLC or the adaptation layer entity or MAC entity on the RLC layer and the MAC layer. You can send by adding The IAB 2 node 1720 selects a radio bearer that is mapped based on a UE bearer identifier, and an adaptation layer entity or RLC layer entity or RLC layer entity on the receiving RLC of the donor base station 1730 or an adaptation layer entity or MAC on the RLC layer and the MAC layer. The terminal bearer identifier for entity-specific identification must be removed from the entity and transmitted to the upper layer.

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

- IAB  Perform L2 forwarding on node-1 ( RLC  On top Adaptation Layer  Protocol architecture for application)

18 is a diagram illustrating a protocol structure in which uplink user data is delivered according to an embodiment. 19 is a diagram illustrating a protocol structure in which uplink user data is delivered according to an embodiment.

As illustrated in FIG. 18, the IAB nodes 1810 and 1820 may separate and forward user data in a 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 on the RLC layer and forward the user data separately on the 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 forward the user data separately on the RLC layer.

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

If there is an adaptation layer above the RLC layer as shown in FIG. 18, a first hop IAB node (IAB) capable of directly wirelessly connecting a terminal-specific RLC bearer (or radio bearer) with the terminal 1600 (for uplink data). RLC bearer (or radio bearer) on the interface between IAB nodes (between IAB 1 and IAB 2) or RLC bearer (or radio bearer) between IAB nodes 1810 and 1820 and donor base station 1830 in the adaptation layer entity of 1, 1810. ). Here, the RLC bearer (RLC channel) represents a lower layer part of the radio bearer configuration consisting of the RLC and the logical channel configuration. In the uplink data transmission through the IAB node, for example, a logical connection or a corresponding channel between a transmitting RLC entity of IAB 1 and a receiving RLC entity of IAB 2 on a wireless backhaul interface between IAB 1 and IAB 2. For convenience of description, in the present specification, an RLC bearer and a radio bearer may be used interchangeably. For example, an RLC bearer may be referred to as a radio bearer, and a radio bearer may be referred to 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 limitation on the number of RLC bearers (or radio bearers) that can be provided on an interface between IAB nodes (between IAB 1 and IAB 2) or on an interface between IAB nodes and donor base stations (between IAB 2 and DgNB), the UE RLC bearer (or radio bearer) on the per-device RLC bearer (or radio bearer) and IAB node (between IAB 1 and IAB 2) interface in the adaptation layer entity of the first hop IAB node (IAB 1) having a direct radio connection Can be configured to map 1 to 1. For example, the 1-to-1 mapping configuration may be configured by the donor base station through an RRC message to the IAB 1 node. As another example, the 1-to-1 mapping configuration may be configured by the donor base station through an F3AP message to an IAB 1 node. 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 terminal and the RLC bearer (or radio bearer) between the IAB node and the donor base station (between IAB 2 and DgNB) may be configured in a one-to-one manner. For example, the 1-to-1 mapping configuration may be configured by the donor base station transmitting an RRC message to the IAB 2 node. As another example, the 1-to-1 mapping configuration may be configured by the donor base station through an F3AP message to an IAB 2 node. 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 limit on the number of RLC bearers (or radio bearers) that can be provided on an interface between IAB nodes (between IAB 1 and IAB 2) or on an interface between IAB nodes and donor base stations (between IAB 2 and DgNB), the UE RLC bearer (or radio bearer) on the per-device RLC bearer (or radio bearer) and IAB node (between IAB 1 and IAB 2) interface in the adaptation layer entity of the first hop IAB node (IAB 1) having a direct radio connection Or, it is necessary to map the RLC bearer (or radio bearer) between UE-specific RLC bearer (or radio bearer) and donor base station (between IAB 2 and DgNB) at an intermediate IAB node (IAB 2) to N: 1. . Where N represents any natural number.

There is currently a limit on the maximum number of radio bearers (or the maximum number of radio bearers that a terminal can provide) between a terminal and a base station. For example, in LTE, the maximum number of DRBs that can be provided is eight. In the case of NR, the maximum number of DRBs that can be provided is only 32. Therefore, when an IAB node accepts a plurality of IAB nodes and terminals and relays them to a donor base station, if the maximum number of DRBs that an IAB node can provide is equal to the maximum number of DRBs that a general terminal can provide, There may be a problem in that the number of RLC bearings / wireless bearers mapped to a radio bearer and a terminal capable of providing a relay between IAB nodes or between an IAB node and a donor base station may occur.

For example, assume the following situation. A node IAB 1 is connected to a terminal-1, a terminal-2, and a terminal-3, and three radio bearers (wireless bearing-1, wireless bearer-2, and wireless bearer-3) are configured in the terminal-1. In addition, two radio bearers (wireless bearing-a and radio bearing-b) are configured in the terminal-2. The terminal-3 is composed of two radio bearers (a radio bearer A and a radio bearer B). In addition, there is no terminal directly connected to the IAB 2 node, and there is no IAB node directly connected to IAB 2 in addition to IAB 1. There is no terminal directly connected to the donor base station, and there is no directly connected IAB node other than IAB 2.

In the above assumption, the number of transmitting RLC entities of the terminal-1 is three, the number of transmitting RLC entities of the terminal-2 is two, and the number of transmitting RLC entities of the terminal 3 is two for uplink data processing. The number of receiving RLC entities of the IAB 1 node peered to this is three (terminal-1 peering entity), two (terminal-2 peering entity), and two (terminal-3 peering entity). The donor base station may determine the number of transmitting RLC entities for data transmission from node IAB 1 to node IAB 2. For example, the number of radio bearers / RLC bearers capable of the same packet forwarding process may be determined according to radio bearers / RCL bearer types / attributes to be provided for each terminal. For example, the radio bearer 1 of the terminal-1, the radio bearer-a of the terminal-2, and the radio bearer-A of the terminal-3 may perform the same packet forwarding process (for example, a default bearer of the same PDU session, or the same). If service provisioning is a radio bearer, three radio bearers / RLC bearers are routed from the IAB-1 node to the IAB 2 node (or one RLC bearer on the interface between the IAB 2 nodes at the IAB 1 node). Can be processed / delivered by mapping to. This may be provided in 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 to the IAB 2 node (for convenience of description). May be mapped to RLC entity-11). Receive RLC entity (RLC-RXa) peered to transmit RLC entity (RLC-TXa) of UE-2 radio bearer-a at node IAB-1 maps to the same transmit RLC entity (RLC entity-11) to node IAB 2 Can be. The receiving RLC entity (RLC-RXA) peered to the transmitting RLC entity (RLC-TXA) of the UE-3 radio bearer-A at the IAB 1 node is mapped 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 distinguished 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 UE and the transmitting RLC entity of the IAB 1 node peered to the receiving RLC entity of the IAB 2 node is determined for each logical channel identification information. It can be provided in conjunction with. For example, the donor base station may provide this by configuring mapping information between logical channel identification information of a specific radio bearer / RLC bearer of a specific terminal and logical channel identification information of an RLC bearer on a radio interface between IAB-1 and IAB 2 in IAB1. have. This may be indicated to the IAB-1 node at the donor base station via an RRC message or an F3AP message. The donor base station may indicate configuration information including mapping information corresponding to an IAB node when an RRC message is instructed to the terminal in order to configure a radio resource for the terminal. For example, when the donor base station transmits the RRC reconfiguration message of the terminal to the terminal through the IAB node, the donor base station may include mapping information corresponding to the IAB node through the F3AP message including the corresponding RRC reconfiguration message.

Alternatively, the RLC entity in the terminal may be distinguished by radio bearer identification information associated with the PDCP entity. For example, the donor base station instructs / configures IAB 1 mapping information between 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 a radio interface between IAB 1 and IAB 2. Thereby, radio bearer identification information associated with the PDCP entity may be provided.

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

As another method, as shown in FIGS. 15 to 17, when the first hop IAB node transmits data for each radio bearer of the terminal to the donor base station through the GTP TEID, the RLC entity (or RLC configuration information) of the terminal at the IAB1 node. May be mapped to a GTP TEID to transmit a radio bearer for each terminal. The mapping between the TEID in the IAB1 node and the transmitting RLC entity of the IAB 1 node peered to the receiving RLC entity of the IAB 2 node may be provided by linking the logical channel identification information with the GTP TEID and the donor base station IP address. As an example, the donor base station converts mapping information between a TEID mapped to a specific radio bearer / RLC bearer of a specific terminal, a donor base station IP address, and logical channel identification information (or radio bearer identification information) on the radio interface between IAB 1 and IAB 2 to IAB 1. Can be directed / configured. This information may be provided included in the adaptation layer configuration information on the RRC message for IAB 1 radio resource configuration. Or it may be provided included in the RLC configuration information on the RRC message for IAB 1 radio resource configuration. Or it may be provided included in the logical channel configuration information on the RRC message for IAB 1 radio resource configuration. Or it may be provided included in the F3AP message transmitted to the IAB 1 node. The configuration information / mapping information includes a terminal identifier, a TEID associated with a radio bearer identifier / logical channel identification information of the terminal, a logical channel identification for an RLC bearer on a radio interface between an IAB 1 and an IAB 2 mapped to a donor base station IP address. Information (or radio bearer identification information). The mapping information may be indicated to the IAB 1 node at 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 1 node when instructing the RRC message to the terminal to configure a radio resource to the terminal. For example, when the donor base station transmits the RRC reconfiguration message of the terminal to the terminal through the IAB node, the donor base station may include mapping information corresponding to the IAB node 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) per terminal at an intermediate IAB node (IAB 2) located at an intermediate IAB node (between IAB 1 and IAB 2)) is connected between an IAB node and a donor base station. Information for mapping to an 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 process at the IAB node (IAB 2) located in the middle according to the radio bearer / RCL bearing type / property to be provided for each terminal. Alternatively, the donor base station may perform the same packet forwarding process at the IAB node (IAB 2) located in the middle according to the radio bearer / RCL bearer type / attribution provided by the IAB node (IAB 1) connected to the lower layer. The number can be determined.

In uplink data transmission, the RLC entity (or RLC configuration information) in the terminal may be distinguished 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 a IAB node to a next hop IAB node (or a donor base station when the next hop is a donor base station) may be provided through logical channel identification information. Can be. As an example, the donor base station may provide this information by indicating / configuring mapping information between logical channel identification information of a specific radio bearer / RLC bearer of a specific terminal and logical channel identification information of an RLC bearer on a radio interface between an IAB 2 and a donor base station to the IAB 2. Can be. This may be indicated to the IAB 2 node at the donor base station via 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 to configure a radio resource to the terminal.

Alternatively, the RLC entity in the terminal may be distinguished by radio bearer identification information associated with the PDCP entity. For example, the donor base station instructs / configures IAB 2 with mapping information between 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 an air interface between IAB 1 and IAB 2. This can be provided by.

The mapping information may be included in the adaptation layer configuration information. The mapping information may include a terminal identifier, radio bearer identifier / logical channel identification information of the 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 be. The IAB-2 may deliver the corresponding MAC entity to the corresponding data 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 logical channel identification information of an RLC bearer on an air interface between IAB 1 and IAB 2 and logical channel identification information of an RLC bearer on an air interface between an IAB 2 and a donor base station may be configured in IAB 2. The mapping information may be indicated to the IAB 2 node at the donor base station 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 UE to configure radio resources to the UE, configuration information including mapping information corresponding to the IAB 2 node is transmitted through the F3AP message. Can be directed.

Alternatively, the RLC entity in the terminal may be distinguished by radio bearer identification information associated with the PDCP entity. As an example, the donor base station configures, in IAB 2, mapping information between the radio bearer identification 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. This can be provided by. The IAB 2 may add one or more pieces of information 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 transmits data of the radio bearer of the terminal to the donor base station through the GTP TEID, the IAB2 node is an RLC entity (or RLC configuration information) of the terminal. A radio bearer for each terminal may be classified and transmitted using the GTP TEID mapped to the donor base station IP address. In the adaptation layer, the IAB1 node adds a TEID and a donor base station IP address on a header for user data (for example, an IP packet) through a radio bearer for each terminal. The adaptation layer of the IAB 2 node may transmit the TEID and the donor base station IP address in association with the logical channel identification information of the transmitting RLC entity. For example, the donor base station may instruct / configure IAB 2 with 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 the IAB 2 and the donor base station. Can be. This information may be provided included in the adaptation layer configuration information on the RRC message for IAB 2 radio resource configuration. Or it may be provided included in the RLC configuration information on the RRC message for IAB 2 radio resource configuration. Or it may be provided included in the logical channel configuration information on the RRC message for IAB 2 radio resource configuration. Or it may be provided included in the F3AP message between the donor base station and the IAB2 node. The configuration information / mapping information includes a terminal identifier, a TEID associated with a radio bearer identifier / logical channel identification information of the terminal, a logical channel identification for an RLC bearer on a radio interface between an IAB 2 and a donor base station mapped to a donor base station IP address. Information (or radio bearer identification information). The mapping information may be indicated to the IAB 2 node at the donor base station through an RRC message or an F3AP message. When the donor base station instructs the terminal in the RRC message to configure the radio resource, 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  Under Adaptation Layer  Application) Protocol Structure Example

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

If an adaptation layer is configured between the MAC and RLC layers (or if the adaptation function is provided using the MAC header on the MAC layer), the UE and the donor base station have PDCP entities per radio bearer, and are not ordinary redundant bearers. The radio bearer needs to configure an RLC entity equal to the number of radio bearers between the terminal and the base station in the IAB node because the PDCP entity is mapped one-to-one to the RLC entity.

This allows the IAB node to send MAC SDUs belonging to different radio bearers (or belonging to different logical channels) in one terminal over 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. Multiplexing can be used.

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

The IAB node multiplexes MAC SDUs belonging to different radio bearers (or different logical channels) of different terminals on 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. Can be.

For example, a UE ID and radio bearer identification information (data radio bearer identification information) for data (for example, an RLC PDU) received by a transmitting adaptation layer entity from an RLC entity (RLC bearer) configured for each radio bearer per terminal, or Adds a header including SRB identification information) / logical channel identification information. The transmission adaptation entity forwards the data with the header added to the transmission MAC entity, and identifies the logical channel associated with the transmission MAC entity by using one or more of a terminal identifier (UE ID) and radio bearer identification information / logical channel identification information. Information can be added on the MAC header. The message with the MAC header added is transmitted by multiplexing on 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 may identify the logical channel identification information associated with the terminal identifier (UE ID) and one or more of the radio bearer identification information / logical channel identification information to classify and process data for each radio bearer for each terminal. . The receiving MAC entity processes the received data and forwards it to the receiving adaptation layer entity. The receiving adaptation layer entity delivers data (RLC PDU) (removing the adaptation header) to the receiving RLC entity mapped to the terminal identifier and the radio bearer identifier / logical channel identification.

As another example, when the MAC entity provides the transmission adaptation layer function, a header field including a terminal identifier (UE ID) in the transmitting MAC entity for data (eg, an RLC PDU) received from an RLC entity configured for each radio bearer per terminal. Add In addition, the MAC header may include logical channel identification information associated with the MAC header using at least one of a terminal identifier (UE ID) and radio bearer identification information (data radio bearer identification information or SRB identification information) and logical channel identification information in the transmitting MAC entity. Add to phase This is multiplexed over 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 may classify and process data for each radio bearer for each terminal through logical channel identification information associated with the at least one information using a terminal identifier (UE ID) and radio bearer identification information / logical channel identification information. The receiving MAC entity processes the received data and then transfers the data (RLC PDU) to the receiving RLC entity (removing the adaptation header) which is mapped to the terminal identifier and radio bearer identifier / logical channel identification.

There is currently a limit on 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 eight. In the case of NR, the maximum number of DRBs that can be provided is only 32. Therefore, when an IAB node accepts a plurality of IAB nodes and terminals and relays them to a donor base station, if the maximum number of DRBs that an IAB node can provide is equal to the maximum number of DRBs that a general terminal can provide, the IAB node There may be a problem in that the number of terminals and radio bearers capable of providing a relay between an IAB node or between an IAB node and a donor base station is limited.

For example, a radio bearer on a radio interface between a first hop IAB node (IAB 1) having a direct radio connection with a terminal in a terminal may be a radio bearer on a radio interface between an IAB node and an IAB node or between an IAB node and a donor base station. Can be mapped to bearers.

For example, assume the following situation.

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

In this case, the number of transmitting RLC entities to terminal-1 is three, the number of transmitting RLC entities at terminal-2 is two, and the number of transmitting RLC entities at terminal-3 is two for uplink data processing. The number of receiving RLC entities of the peered IAB 1 node is three, two, and two, respectively. The donor base station may determine the number of transmitting RLC entities from node IAB 1 to node IAB 2. For example, the number of radio bearers capable of the same packet forwarding process may be determined according to the radio bearer type to be provided for each terminal. For example, the radio bearer 1 of the terminal-1, the radio bearer-a of the terminal-2, and the radio bearer-A of the terminal-3 may perform the same packet forwarding process (for example, a 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 to the IAB 2 node (for convenience of description). May be mapped to RLC entity-11). The receiving RLC entity (RLC-RXa) peered to the transmitting RLC entity (RLC-TXa) of the UE-2 radio bearer-a at the IAB 1 node may be mapped to the same transmitting RLC entity (RLC entity-11) to the IAB 2 node. Can be. The receiving RLC entity (RLC-RXA) peered to the transmitting RLC entity (RLC-TXA) of the UE-3 radio bearer-A at the IAB 1 node may be mapped to the same transmitting RLC entity (RLC entity-11) to the IAB 2 node. Can be.

The RLC entity in the terminal may be distinguished 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 per terminal 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. For example, the donor base station may provide this by configuring 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 in IAB 1.

Alternatively, the RLC entity in the terminal may be distinguished by radio bearer identification information associated with the PDCP entity. As an example, the donor base station may provide this by configuring mapping information between radio bearer identification information of a terminal and logical channel identification information on a radio interface between IAB 1 and IAB 2 in IAB 1. This may be indicated to the IAB 1 node at the donor base station via the RRC message. When the donor base station instructs the RRC message for configuring a radio resource to the terminal, 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 may separate the data by RLC bearer / radio bearer / logical channel identification information, and buffer / store / process the data to transmit the received adaptation layer to the associated UE-specific RLC bearer.

Similar to the method described above, an RLC bearer on an interface between IAB nodes (between IAB 1 and IAB 2) (or UE-specific RLC bearer at an intermediate IAB node (IAB 2)) is connected between an IAB node and a donor base station (IAB 2 and DgNB). There is also a method of configuring information for mapping to the RLC bearer.

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

Alternatively, the RLC entity in the terminal may be distinguished by radio bearer identification information associated with the PDCP entity. For example, the donor base station configures IAB 1 by mapping mapping information between 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 a radio interface between IAB 1 and IAB 2. Can provide.

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

As an example, the donor base station adaptation layer entity may deliver 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 may separate the data by RLC bearer / radio bearer / logical channel identification information, and buffer / store / process the data to transmit the received adaptation layer to the associated UE-specific RLC bearer.

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

Alternatively, the RLC entity in the terminal may be distinguished by radio bearer identification information associated with the PDCP entity. As an example, the donor base station configures the radio bearer identification information of the RLC bearer on the radio interface between the IAB 1 and the IAB 2 and the mapping information between the logical channel identification information (or radio bearer identification information) on the radio interface between the IAB 2 and the donor base station on the IAB 2. This can be provided by. The IAB 2 may add the mapping information 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 scheme described above are applied, the terminal can effectively transmit and receive data by establishing a connection to the base station through a multi-hop relay node under the control of the donor base station.

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 illustrating a configuration of a relay node 2000 according to another embodiment.

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

The controller 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 higher layer connection may mean F3AP (F3 Application Protocol).

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

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

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

The transmitter 2020 may add 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 refer to a GPRS Tunnelling Protocol (GTP) Tunnel Endpoint Identifier (TEID) or a donor base station IP address received from 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, 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 UE in the payload of the F3AP and delivers the RRC message to the donor base station through the signaling radio bearer. In addition, in order to transmit via the signaling radio bearer, the donor base station performs siphering on the PDCP entity.

In addition, the receiving unit 2030 may receive the uplink user data from the terminal in the method of processing the uplink user data.

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

The controller 2010 may select 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. 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 for transmitting uplink user data using donor base station address information. For example, the donor base station address information may be a GPRS Tunnelling Protocol (GTP) Tunnel endpoint identifier (TEID) or a donor base station IP address received from 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 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, backhaul RLC channel mapping information is required to select a backhaul RLC channel using at least one of the above-described terminal bearer identifier and donor base station address information. 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 of 1 or more) mapping information between at least one of the terminal bearer identifier and the donor base station address information and the 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 the logical channel configuration information of the RRC message. That is, the controller 2010 can configure the backhaul RLC channel using the logical channel configuration information of the RRC message.

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

Meanwhile, the reception unit 2030 may receive an RRC connection request message from the terminal before receiving the uplink user data from the terminal. In addition, 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 comprise the step.

In addition, the control unit 2010 includes the RRC message of the terminal necessary to perform the above-described embodiment in the F3AP message and delivers the information through the SRB, and uses the logical channel identification information to transmit the uplink user data of the terminal to the backhaul RLC. Controls the overall operation of the relay node 2000 for transmission over 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 disclosure with a terminal, another relay node, and a donor base station.

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

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

In the case of a hardware implementation, the method according to the 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), a processor, a controller, a microcontroller, a microprocessor, and the like.

In the case of an implementation by firmware or software, the method according to the 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 a memory unit and driven by a processor. The memory unit may be located inside or outside the processor, and may exchange data with the processor by various known means.

In addition, the terms "system", "processor", "controller", "component", "module", "interface", "model" and "unit" described above generally refer to computer-related entity hardware, hardware and software. May mean a combination, software, or running software. For example, the aforementioned components may be, but are not limited to, a process driven by a processor, a processor, a controller, a control processor, an object, an execution thread, a program, and / or a computer. For example, both an application running on a controller or processor and a controller or processor can be components. One or more components can reside within a process and / or thread of execution and a component can be located on one system or deployed on more than one system.

The above description and the accompanying drawings are merely illustrative of the technical idea, and a person of ordinary skill in the art may combine, separate, substitute, and substitute the components without departing from the essential characteristics of the present technology. Many modifications and variations, including variations, are possible. Accordingly, the embodiments disclosed herein are not intended to limit the present invention, but to describe the present invention, and the scope of the present invention is not limited thereto. The scope of protection of the technical idea should be interpreted by the claims, and all technical ideas within the equivalent scope should be interpreted as being included in the scope of the present specification.

Claims (20)

In the relay node processing uplink user data,
Receiving uplink user data from a terminal;
Deriving a UE bearer identifier (UE-bearer-ID) by using logical channel identification information associated with an RLC PDU of the uplink user data;
Selecting a backhaul RLC channel for transmitting the uplink user data based on at least one of the terminal bearer identifier and donor base station address information; And
Transmitting the uplink user data to the donor base station or another relay node through the selected backhaul RLC channel. The method of claim 1,
The relay node,
And an integrated access and backhaul (IAB) node connected to the terminal through wireless access and connected to the other relay node or the donor base station through a wireless backhaul. The method of claim 1,
The donor base station address information,
And a donor base station (GTP) Tunnel Endpoint Identifier (TEID) or a donor base station IP address received from the donor base station. The method of claim 1,
Selecting the backhaul RLC channel,
And selecting the backhaul RLC channel based on backhaul RLC channel mapping information included in a terminal context setup message of the terminal received from the donor base station. The method of claim 4, wherein
The backhaul RLC channel mapping information is
And at least one of the terminal bearer identifier and the donor base station address information and N: 1 (N is a natural number of 1 or more) mapping information between the backhaul RLC channel. The method of claim 4, wherein
The backhaul RLC channel mapping information is
And mapping information between the terminal bearer identifier and the donor base station address information. The method of claim 1,
The backhaul RLC channel is,
And configured according to the logical channel configuration information of the RRC message. The method of claim 1,
The transmitting step,
The uplink user data includes at least one of the terminal bearer identifier, the donor base station address information, the logical channel identification information, and mapping information between the logical channel identification information and the backhaul RLC channel in the adaptation entity of the relay node. And transmitting. The method of claim 1,
Before the step of receiving the uplink data,
Receiving an RRC connection request message from the terminal; And
Sending the RRC connection request message to the donor base station via a signaling radio bearer or an F3AP message. The method of claim 9,
The signaling radio bearer or F3AP message,
And the donor base station address information in an adaptation entity. In a relay node for processing uplink user data,
Receiving unit for receiving uplink user data from the terminal;
Deriving a UE bearer identifier (UE-bearer-ID) by using the logical channel identification information associated with the RLC PDU of the uplink user data,
A control unit for selecting a backhaul RLC channel for transmitting the uplink user data based on at least one of the terminal bearer identifier and donor base station address information; And
And a transmitter configured to transmit the uplink user data to the donor base station or another relay node through the selected backhaul RLC channel. The method of claim 11,
The relay node,
And a relay node connected to the terminal through wireless access and connected to the other relay node or the donor base station through a wireless backhaul. The method of claim 11,
The donor base station address information,
And a donor base station IP address or a GPRS Tunnelling Protocol (GTP) Tunnel Endpoint Identifier (TEID) received from the donor base station. The method of claim 11,
The control unit,
And the backhaul RLC channel is selected based on backhaul RLC channel mapping information included in a terminal context setup message of the terminal received from the donor base station. The method of claim 14,
The backhaul RLC channel mapping information is
And at least one of the terminal bearer identifier and donor base station address information and N: 1 (N is a natural number of 1 or more) mapping information between the backhaul RLC channel. The method of claim 14,
The backhaul RLC channel mapping information is
And relaying information between the terminal bearer identifier and the donor base station address information. The method of claim 11,
The backhaul RLC channel is,
And a relay node configured according to the logical channel configuration information of the RRC message. The method of claim 11,
The transmitting unit,
The uplink user data includes at least one of the terminal bearer identifier, the donor base station address information, the logical channel identification information, and mapping information between the logical channel identification information and the backhaul RLC channel in the adaptation entity of the relay node. Relay node, characterized in that for transmitting. The method of claim 11,
When the receiver receives the RRC connection request message from the terminal,
The transmitter transmits the RRC connection request message to the donor base station through a signaling radio bearer or an F3AP message. The method of claim 19,
The signaling radio bearer or F3AP message,
Relay node, characterized in that configured to include the donor base station address information in the adaptation entity.

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