KR20210039868A - Method and apparatus for configuring signaling radio bearer for integrated system of backhole and access hole - Google Patents

Abstract

The present disclosure relates to a communication technique that converges a 5G communication system for supporting a higher data rate after a 4G system with IoT technology, and a system thereof. The present disclosure can be applied to an intelligent service (for example, smart home, smart building, smart city, smart car or connected car, healthcare, digital education, retail business, security and safety related services, and the like) based on 5G communication technology and IoT-related technology. In addition, the present disclosure relates to a method for establishing a wireless bearer and a device for performing the same. Therefore, the present invention is capable of providing an improved method for establishing the wireless bearer and the device for performing the same.

Description

Signal radio bearer setup method and apparatus for integrated backhaul and access hole systems {METHOD AND APPARATUS FOR CONFIGURING SIGNALING RADIO BEARER FOR INTEGRATED SYSTEM OF BACKHOLE AND ACCESS HOLE}

The present invention relates to a method for setting up a radio bearer. The present invention relates to a method for setting up a radio bearer for a backhaul and access hole integration system.

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

Meanwhile, the Internet is evolving from a human-centered connection network in which humans create and consume information, to an Internet of Things (IoT) network that exchanges and processes information between distributed components such as objects. IoE (Internet of Everything) technology, which combines IoT technology with big data processing technology through connection with cloud servers, etc., is also emerging. In order to implement IoT, technological elements such as sensing technology, wired/wireless communication and network infrastructure, service interface technology, and security technology are required. , M2M), and MTC (Machine Type Communication) technologies are being studied. In the IoT environment, intelligent IT (Internet Technology) services that create new value in human life by collecting and analyzing data generated from connected objects can be provided. IoT is the field of smart home, smart building, smart city, smart car or connected car, smart grid, healthcare, smart home appliance, advanced medical service, etc. through the convergence and combination of existing IT (information technology) technology and various industries. Can be applied to.

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

A technical problem to be achieved in an embodiment of the present invention is to provide an improved method for setting up a radio bearer and an apparatus for performing the same. In addition, a technical problem to be achieved in an embodiment of the present invention is to provide a method for configuring a split SRB3 for transmission of a control signal of an IAB node in an integrated access backhaul (IAB) system, and the control signal of an IAB node is an NR Uu interface of an IAB parent. Although it may be transmitted through, in order to ensure connection robustness, a method of connecting to an LTE master node (MN) is provided.

According to an embodiment of the present invention, there is provided a control signal processing method in a wireless communication system, the method comprising: receiving a first control signal transmitted from a base station; Processing the received first control signal; And transmitting a second control signal generated based on the processing to the base station.

The technical problems to be achieved in the embodiments of the present invention are not limited to the above-mentioned technical problems, and other technical problems that are not mentioned are clear to those of ordinary skill in the technical field to which the present invention belongs from the following description. It will be understandable.

According to an embodiment of the present invention, it is possible to provide an improved method for setting up a radio bearer and an apparatus for performing the same.

In addition, according to an embodiment of the present invention, a method for configuring a split SRB of an IAB node may be provided, and in this case, a method and apparatus for providing connection robustness using an LTE MN may be provided.

1 is a diagram illustrating a structure of an LTE system according to an embodiment of the present invention.
2 is a diagram showing a radio protocol structure of an LTE system according to an embodiment of the present invention.
3 is a diagram showing the structure of a next-generation mobile communication system according to an embodiment of the present invention.
4 is a diagram showing a radio protocol structure of a next-generation mobile communication system according to an embodiment of the present invention.
5 is a block diagram illustrating an internal structure of a terminal according to an embodiment of the present invention.
6 is a block diagram showing the configuration of a base station according to an embodiment of the present invention.
FIG. 7 is a diagram illustrating a process in which an MN directly requests the establishment of a split SRB3 to a secondary node (SN) according to an embodiment of the present invention, and the SN confirms the establishment of a split srb3 and transfers it back to the MN.
8 is a situation in which the SgNB is added to the UE without the presence of the split SRB3 according to an embodiment of the present invention, and additionally, when the eNB requests the configuration of the split SRB3 according to the determination of the SN, the eNB is the MCG of the split SRB3 ( master cell group) is a diagram showing a process of determining and responding to the part and instructing the UE to set up.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. In this case, it should be noted that the same components in the accompanying drawings are indicated by the same reference numerals as possible. In addition, detailed descriptions of known functions and configurations that may obscure the subject matter of the present invention will be omitted.

In describing the embodiments herein, descriptions of technical contents that are well known in the technical field to which the present invention pertains and are not directly related to the present invention will be omitted. This is to more clearly convey the gist of the present invention by omitting unnecessary description.

For the same reason, some elements in the accompanying drawings are exaggerated, omitted, or schematically illustrated. In addition, the size of each component does not fully reflect the actual size. The same reference numerals are assigned to the same or corresponding components in each drawing.

Advantages and features of the present invention, and a method of achieving them will become apparent with reference to the embodiments described below in detail together with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but may be implemented in various different forms, and only these embodiments make the disclosure of the present invention complete, and the general knowledge in the technical field to which the present invention pertains. It is provided to completely inform the scope of the invention to the possessor, and the invention is only defined by the scope of the claims. The same reference numerals refer to the same elements throughout the specification.

At this time, it will be appreciated that each block of the flowchart diagrams and combinations of the flowchart diagrams may be executed by computer program instructions. Since these computer program instructions can be mounted on the processor of a general purpose computer, special purpose computer or other programmable data processing equipment, the instructions executed by the processor of the computer or other programmable data processing equipment are described in the flowchart block(s). It creates a means to perform functions. These computer program instructions can also be stored in computer-usable or computer-readable memory that can be directed to a computer or other programmable data processing equipment to implement a function in a particular way, so that the computer-usable or computer-readable memory It is also possible for the instructions stored in the flow chart to produce an article of manufacture containing instruction means for performing the functions described in the flowchart block(s). Since computer program instructions can also be mounted on a computer or other programmable data processing equipment, a series of operating steps are performed on a computer or other programmable data processing equipment to create a computer-executable process to create a computer or other programmable data processing equipment. It is also possible for instructions to perform processing equipment to provide steps for executing the functions described in the flowchart block(s).

In addition, each block may represent a module, segment, or part of code that contains one or more executable instructions for executing the specified logical function(s). In addition, it should be noted that in some alternative execution examples, the functions mentioned in the blocks may occur out of order. For example, two blocks shown in succession may in fact be executed substantially simultaneously, or the blocks may sometimes be executed in the reverse order depending on the corresponding function.

In this case, the term'~ unit' used in this embodiment refers to software or hardware components such as FPGA or ASIC, and'~ unit' performs certain roles. However,'~ part' is not limited to software or hardware. The'~ unit' may be configured to be in an addressable storage medium, or may be configured to reproduce one or more processors. Thus, as an example,'~ unit' refers to components such as software components, object-oriented software components, class components, and task components, processes, functions, properties, and procedures. , Subroutines, segments of program code, drivers, firmware, microcode, circuits, data, databases, data structures, tables, arrays, and variables. Components and functions provided in the'~ units' may be combined into a smaller number of elements and'~ units', or may be further separated into additional elements and'~ units'. In addition, components and'~ units' may be implemented to play one or more CPUs in a device or a security multimedia card.

A term for identifying an access node used in the following description, a term for network entities, a term for messages, a term for an interface between network objects, a term for various identification information And the like are illustrated for convenience of description. Accordingly, the present invention is not limited to the terms described below, and other terms referring to objects having an equivalent technical meaning may be used.

For convenience of description below, the present invention uses terms and names defined in the 3GPP 3rd Generation Partnership Project Long Term Evolution (LTE) standard. However, the present invention is not limited by the terms and names, and may be equally applied to systems conforming to other standards.

In various embodiments of the present invention, the MN may be interpreted as a master base station, and the SN may be interpreted as a secondary base station. In addition, in various embodiments of the present invention, the MN and the SN may be interpreted as different base stations and base stations using different radio access technologies (RATs), and in some cases, may be used as base stations using the same RAT. MN and SN may be classified using a general expression such as a first base station and a second base station.

In addition, in various embodiments of the present invention, the eNB and the gNB may be referred to as a base station, and may be classified using a general expression such as a first base station and a second base station in order to distinguish between the eNB and the gNB.

1 is a diagram illustrating a structure of an LTE system according to an embodiment of the present invention.

Referring to Figure 1, as shown in the radio access network of the LTE system is a next-generation base station (Evolved Node B, hereinafter ENB, Node B or base station) (1-05, 1-10, 1-15, 1-20) and It may be composed of a mobility management entity (Mobility Management Entity, MME) (1-25) and an S-GW (1-30, Serving-Gateway). User Equipment (hereinafter referred to as UE or UE) 1-35 may access an external network through ENBs 1-05 to 1-20 and S-GWs 1-30.

In FIG. 1, ENBs 1-05 to 1-20 may correspond to an existing node B of the UMTS system. The ENB is connected to the UE (1-35) through a radio channel and can perform a more complex role than the existing Node B. In the LTE system, all user traffic including real-time services such as VoIP (Voice over IP) through the Internet protocol can be serviced through a shared channel. Accordingly, there is a need for a device for scheduling by collecting state information such as a buffer state, an available transmission power state, and a channel state of the UEs, and the ENBs 1-05 to 1-20 may be in charge of this. One ENB can typically control multiple cells. For example, in order to implement a transmission rate of 100 Mbps, the LTE system may use orthogonal frequency division multiplexing (OFDM) in a 20 MHz bandwidth, for example, as a radio access technology. In addition, an adaptive modulation and coding (AMC) scheme for determining a modulation scheme and a channel coding rate according to the channel state of the terminal may be applied. The S-GW 1-30 is a device that provides a data bearer, and may create or remove a data bearer under the control of the MME 1-25. The MME 1-25 is a device responsible for various control functions as well as a mobility management function for the terminal 1-35, and may be connected to a plurality of base stations 1-05 to 1-20.

2 is a diagram showing a radio protocol structure of an LTE system according to an embodiment of the present invention.

Referring to Figure 2, the radio protocol of the LTE system is a packet data convergence protocol (Packet Data Convergence Protocol, PDCP) (2-05, 2-40), radio link control (Radio Link Control, RLC) in the terminal and the ENB, respectively. 2-10, 2-35), medium access control (MAC) (2-15, 2-30). PDCP (2-05, 2-40) may be in charge of operations such as IP header compression/restore. The main functions of PDCP (2-05, 2-40) can be summarized as follows.

-Header compression and decompression (ROHC only)

-Transfer of user data

-In-sequence delivery of upper layer PDUs at PDCP re-establishment procedure for RLC AM

-Order reordering function (For split bearers in DC (only support for RLC AM): PDCP PDU routing for transmission and PDCP PDU reordering for reception)

-Duplicate detection of lower layer SDUs at PDCP re-establishment procedure for RLC AM

-Retransmission of PDCP SDUs at handover and, for split bearers in DC, of PDCP PDUs at PDCP data-recovery procedure, for RLC AM

-Encryption and decryption function (Ciphering and deciphering)

-Timer-based SDU discard in uplink.

Radio Link Control (RLC) (2-10, 2-35) can perform an automatic repeat request (ARQ) operation by reconfiguring a PDCP packet data unit (PDU) to an appropriate size. . The main functions of RLC (2-10, 2-35) can be summarized as follows.

-Data transfer function (Transfer of upper layer PDUs)

-ARQ function (Error Correction through ARQ (only for AM data transfer))

-Concatenation, segmentation and reassembly of RLC SDUs (only for UM and AM data transfer)

-Re-segmentation of RLC data PDUs (only for AM data transfer)

-Reordering of RLC data PDUs (only for UM and AM data transfer)

-Duplicate detection (only for UM and AM data transfer)

-Error detection function (Protocol error detection (only for AM data transfer))

-RLC SDU discard function (RLC SDU discard (only for UM and AM data transfer))

-RLC re-establishment

The MACs 2-15 and 2-30 are connected to several RLC layer devices configured in one terminal, and may perform an operation of multiplexing RLC PDUs to MAC PDUs and demultiplexing RLC PDUs from MAC PDUs. The main functions of MAC (2-15, 2-30) can be summarized as follows.

-Mapping between logical channels and transport channels

-Multiplexing/demultiplexing of MAC SDUs belonging to one or different logical channels into/from transport blocks (TB) delivered to/from the physical layer on transport channels

-Scheduling information reporting

-Hybrid automatic repeat request (HARQ) function (Error correction through HARQ)

-Priority handling between logical channels of one UE

-Priority handling between UEs by means of dynamic scheduling

-MBMS service identification

-Transport format selection

-Padding function

The physical layer (2-20, 2-25) channel-codes and modulates upper layer data, converts it into OFDM symbols, and transmits it to the radio channel, or demodulates the OFDM symbol received through the radio channel, decodes the channel, and delivers it to the upper layer. You can do the action.

3 is a diagram showing the structure of a next-generation mobile communication system according to an embodiment of the present invention.

3, the radio access network of the next-generation mobile communication system (hereinafter referred to as NR or 2g) includes a next-generation base station (New Radio Node B, hereinafter referred to as NR gNB or NR base station) (3-10) and a next-generation radio core network (New Radio Core). Network, NR CN) (3-05). Next-generation radio user equipment (New Radio User Equipment, NR UE or terminal) 3-15 may access an external network through NR gNB 3-10 and NR CN 3-05.

In FIG. 3, the NR gNB 3-10 may correspond to an Evolved Node B (eNB) of an existing LTE system. The NR gNB 3-10 is connected to the NR UE 3-15 through a radio channel and can provide a service superior to that of the existing Node B. In a next-generation mobile communication system, all user traffic can be serviced through a shared channel. Accordingly, there is a need for an apparatus for scheduling by collecting state information such as a buffer state, an available transmit power state, and a channel state of the UEs, and the NR NB 3-10 may be in charge of this. One NR gNB can control multiple cells. In the next-generation mobile communication system, in order to implement ultra-high-speed data transmission compared to the current LTE, a bandwidth greater than the current maximum bandwidth may be applied. In addition, an orthogonal frequency division multiplexing (OFDM) technique may be used as a radio access technique, and an additional beamforming technique may be applied. In addition, an adaptive modulation and coding method (hereinafter referred to as AMC) for determining a modulation scheme and a channel coding rate according to a channel state of the terminal may be applied. The NR CN (3-05) may perform functions such as mobility support, bearer configuration, and quality of service (QoS) configuration. The NR CN (3-05) is a device responsible for various control functions as well as a mobility management function for a terminal, and may be connected to a plurality of base stations. In addition, the next-generation mobile communication system can be linked with the existing LTE system, and the NR CN (3-05) can be connected to the MME (3-25) through a network interface. The MME 3-25 may be connected to the eNB 3-30, which is an existing base station.

4 is a diagram showing a radio protocol structure of a next-generation mobile communication system according to an embodiment of the present invention.

Referring to FIG. 4, radio protocols of the next-generation mobile communication system include NR Service Data Adaptation Protocol (SDAP) (4-01, 4-45) and NR PDCP (4-05, respectively) in a terminal and an NR base station. 4-40), NR RLC (4-10, 4-35), NR MAC (4-15, 4-30).

The main functions of the NR SDAP (4-01, 4-45) may include some of the following functions.

- Transfer of user plane data

- Mapping between a QoS flow and a data radio bearer (DRB) for both DL and UL for uplink and downlink

- Marking QoS flow ID for uplink and downlink (marking QoS flow ID in both DL and UL packets)

- A function of mapping a relective QoS flow to a data bearer for uplink SDAP PDUs (reflective QoS flow to DRB mapping for the UL SDAP PDUs).

For SDAP layer devices, the UE uses a radio resource control (RRC) message for each PDCP layer device, bearer or logical channel, whether to use the header of the SDAP layer device or whether to use the function of the SDAP layer device. Can be set. When the SDAP header is set, the terminal includes a non-access layer (Non-Access Stratum, NAS) QoS (Quality of Service) reflection setting 1-bit indicator (NAS reflective QoS) and an access layer (Access Stratum, AS) QoS of the SDAP header. With the reflection configuration 1-bit indicator (AS reflective QoS), it is possible to instruct the UE to update or reconfigure mapping information for the uplink and downlink QoS flows and data bearers. The SDAP header may include QoS flow ID information indicating QoS. QoS information can be used as data processing priority, scheduling information, etc. to support smooth service.

The main functions of NR PDCP (4-05, 4-40) may include some of the following functions.

-Header compression and decompression (ROHC only)

-Transfer of user data

-In-sequence delivery of upper layer PDUs

-Out-of-sequence delivery of upper layer PDUs

-Order reordering function (PDCP PDU reordering for reception)

-Duplicate detection of lower layer SDUs

-Retransmission of PDCP SDUs

-Encryption and decryption function (Ciphering and deciphering)

-Timer-based SDU discard in uplink.

In the above description, the reordering function of the NR PDCP device may mean a function of reordering PDCP PDUs received from a lower layer in order based on a PDCP sequence number (SN). The reordering function (reordering) of the NR PDCP device may include a function of transferring data to an upper layer in a rearranged order, or may include a function of directly transferring data without considering the order, and the order is rearranged and lost. It may include a function of recording lost PDCP PDUs, may include a function of reporting a status of lost PDCP PDUs to a transmitting side, and a function of requesting retransmission of lost PDCP PDUs. have.

The main functions of the NR RLC (4-10, 4-35) may include some of the following functions.

-Data transfer function (Transfer of upper layer PDUs)

-In-sequence delivery of upper layer PDUs

-Out-of-sequence delivery of upper layer PDUs

-ARQ function (Error Correction through ARQ)

-Concatenation, segmentation and reassembly of RLC SDUs

-Re-segmentation of RLC data PDUs

-Reordering of RLC data PDUs

-Duplicate detection

-Protocol error detection

-RLC SDU discard function

-RLC re-establishment

In the above description, in-sequence delivery of the NR RLC device may mean a function of sequentially delivering RLC SDUs received from a lower layer to an upper layer. When one RLC SDU is originally divided into several RLC SDUs and received, the in-sequence delivery function of the NR RLC device may include a function of reassembling and delivering it.

In-sequence delivery of the NR RLC device may include a function of rearranging received RLC PDUs based on an RLC sequence number (SN) or a PDCP sequence number (SN). It may include a function of recording lost RLC PDUs, may include a function of reporting a status of lost RLC PDUs to a transmitting side, and a function of requesting retransmission of lost RLC PDUs. have.

In-sequence delivery of the NR RLC device may include a function of sequentially delivering only RLC SDUs prior to the lost RLC SDU to a higher layer when there is a lost RLC SDU.

The in-sequence delivery function of the NR RLC device may include a function of sequentially delivering all RLC SDUs received before the timer starts to a higher layer if a predetermined timer expires even if there is a lost RLC SDU. have.

In-sequence delivery of the NR RLC device may include a function of sequentially delivering all RLC SDUs received so far to a higher layer if a predetermined timer expires even if there is a lost RLC SDU.

The NR RLC device may process RLC PDUs in an order of reception regardless of the sequence number (Out-of sequence delivery) and deliver them to the NR PDCP device.

When the NR RLC device receives a segment, it may receive segments stored in a buffer or to be received at a later time, reconfigure it into one complete RLC PDU, and then transmit it to the NR PDCP device.

The NR RLC layer may not include a concatenation function, and may perform a function in the NR MAC layer or may be replaced with a multiplexing function of the NR MAC layer.

In the above description, out-of-sequence delivery of the NR RLC device may mean a function of directly delivering RLC SDUs received from a lower layer to an upper layer regardless of an order. Out-of-sequence delivery of the NR RLC device may include a function of reassembling and delivering when one RLC SDU is originally divided into several RLC SDUs and received. Out-of-sequence delivery of the NR RLC device may include a function of storing RLC SNs or PDCP SNs of received RLC PDUs, arranging the order, and recording the lost RLC PDUs.

NR MAC (4-15, 4-30) can be connected to multiple NR RLC layer devices configured in one device, and the main functions of NR MAC (4-15, 4-30) include some of the following functions. can do.

-Mapping between logical channels and transport channels

-Multiplexing and demultiplexing function (Multiplexing/demultiplexing of MAC SDUs)

-Scheduling information reporting

-HARQ function (Error correction through HARQ)

-Priority handling between logical channels of one UE

-Priority handling between UEs by means of dynamic scheduling

-MBMS service identification

-Transport format selection

-Padding function

The NR PHY layer (4-20, 4-25) channel-codes and modulates upper layer data, converts it into OFDM symbols, and transmits it to the radio channel, or demodulates and channel-decodes OFDM symbols received through the radio channel to the upper layer. You can perform the transfer operation.

5 is a block diagram illustrating an internal structure of a terminal according to an embodiment of the present invention.

Referring to the drawing, the terminal includes a radio frequency (RF) processing unit 5-10, a baseband processing unit 5-20, a storage unit 5-30, and a control unit 5-40. I can. In addition, the control unit 5-40 may further include a multiple connection processing unit 5-42.

The RF processing unit 5-10 performs a function of transmitting and receiving a signal through a wireless channel such as band conversion and amplification of a signal. That is, the RF processing unit 5-10 up-converts the baseband signal provided from the baseband processing unit 5-20 into an RF band signal and transmits it through an antenna, and the RF band signal received through the antenna Is down-converted to a baseband signal. For example, the RF processing unit 5-10 may include a transmission filter, a reception filter, an amplifier, a mixer, an oscillator, a digital to analog convertor (DAC), an analog to digital convertor (ADC), and the like. I can. In the drawing, only one antenna is shown, but the terminal may include a plurality of antennas. In addition, the RF processing unit 5-10 may include a plurality of RF chains. Furthermore, the RF processing unit 5-10 may perform beamforming. For the beamforming, the RF processing unit 5-10 may adjust a phase and a magnitude of each of signals transmitted/received through a plurality of antennas or antenna elements. In addition, the RF processing unit may perform MIMO, and may receive multiple layers when performing the MIMO operation.

The baseband processing unit 5-20 performs a function of converting between a baseband signal and a bit stream according to the physical layer standard of the system. For example, when transmitting data, the baseband processing unit 5-20 generates complex symbols by encoding and modulating a transmission bit stream. In addition, when receiving data, the baseband processing unit 5-20 restores a received bit stream through demodulation and decoding of the baseband signal provided from the RF processing unit 5-10. For example, in the case of the OFDM (orthogonal frequency division multiplexing) method, when transmitting data, the baseband processor 5-20 generates complex symbols by encoding and modulating a transmission bit stream, and subcarriers the complex symbols. After mapping to, OFDM symbols are constructed through an inverse fast Fourier transform (IFFT) operation and a cyclic prefix (CP) insertion. In addition, when receiving data, the baseband processing unit 5-20 divides the baseband signal provided from the RF processing unit 5-10 in units of OFDM symbols, and maps them to subcarriers through fast Fourier transform (FFT). After restoring the received signals, the received bit stream is restored through demodulation and decoding.

The baseband processing unit 5-20 and the RF processing unit 5-10 transmit and receive signals as described above. Accordingly, the baseband processing unit 5-20 and the RF processing unit 5-10 may be referred to as a transmission unit, a reception unit, a transmission/reception unit, a transceiver, or a communication unit. Furthermore, at least one of the baseband processing unit 5-20 and the RF processing unit 5-10 may include a plurality of communication modules to support a plurality of different wireless access technologies. In addition, at least one of the baseband processing unit 5-20 and the RF processing unit 5-10 may include different communication modules to process signals of different frequency bands. For example, the different wireless access technologies may include a wireless LAN (eg, IEEE 802.11), a cellular network (eg, LTE), and the like. In addition, the different frequency bands may include a super high frequency (SHF) (eg, 2.NRHz, NRhz) band, and a millimeter wave (eg, 60GHz) band.

The storage unit 5-30 stores data such as a basic program, an application program, and setting information for the operation of the terminal. In particular, the storage unit 5-30 may store information related to a second access node performing wireless communication using a second wireless access technology. In addition, the storage unit 5-30 provides stored data according to the request of the control unit 5-40.

The controller 5-40 controls overall operations of the terminal. For example, the control unit 5-40 transmits and receives signals through the baseband processing unit 5-20 and the RF processing unit 5-10. In addition, the control unit 5-40 writes and reads data in the storage unit 5-40. To this end, the control unit 5-40 may include at least one processor. For example, the controller 5-40 may include a communication processor (CP) that controls communication and an application processor (AP) that controls an upper layer such as an application program. In addition, the controller 5-40 may control an operation of a terminal or an entity corresponding thereto according to various embodiments of the present disclosure.

6 is a block diagram showing the configuration of a base station according to an embodiment of the present invention.

As shown in the figure, the base station includes an RF processing unit 6-10, a baseband processing unit 6-20, a backhaul communication unit 6-30, a storage unit 6-40, and a control unit 6-50. It may include. The control unit 6-50 may further include a multiple connection processing unit 6-52.

The RF processing unit 6-10 performs a function for transmitting and receiving a signal through a wireless channel such as band conversion and amplification of a signal. That is, the RF processing unit 6-10 up-converts the baseband signal provided from the baseband processing unit 6-20 to an RF band signal, and then transmits it through an antenna, and an RF band signal received through the antenna. Is down-converted to a baseband signal. For example, the RF processing unit 6-10 may include a transmission filter, a reception filter, an amplifier, a mixer, an oscillator, a DAC, an ADC, and the like. In the drawing, only one antenna is shown, but the first access node may include a plurality of antennas. In addition, the RF processing unit 6-10 may include a plurality of RF chains. Furthermore, the RF processing unit 6-10 may perform beamforming. For the beamforming, the RF processing unit 6-10 may adjust a phase and a magnitude of each of signals transmitted and received through a plurality of antennas or antenna elements. The RF processing unit may perform a downlink MIMO operation by transmitting one or more layers.

The baseband processing unit 6-20 performs a function of converting between a baseband signal and a bit string according to the physical layer standard of the first wireless access technology. For example, when transmitting data, the baseband processing unit 6-20 generates complex symbols by encoding and modulating a transmission bit stream. In addition, when receiving data, the baseband processing unit 6-20 restores a received bit stream through demodulation and decoding of the baseband signal provided from the RF processing unit 6-10. For example, in the case of the OFDM scheme, when transmitting data, the baseband processor 6-20 generates complex symbols by encoding and modulating a transmission bit stream, mapping the complex symbols to subcarriers, and then IFFT OFDM symbols are configured through calculation and CP insertion. In addition, when receiving data, the baseband processing unit 6-20 divides the baseband signal provided from the RF processing unit 6-10 in units of OFDM symbols, and reconstructs signals mapped to subcarriers through FFT operation. After that, the received bit stream is restored through demodulation and decoding. The baseband processing unit 6-20 and the RF processing unit 6-10 transmit and receive signals as described above. Accordingly, the baseband processing unit 6-20 and the RF processing unit 6-10 may be referred to as a transmission unit, a reception unit, a transmission/reception unit, a transceiver, a communication unit, or a wireless communication unit.

The backhaul communication unit 6-30 provides an interface for performing communication with other nodes in the network. That is, the backhaul communication unit 6-30 converts a bit stream transmitted from the base station to another node, for example, an auxiliary base station, a core network, etc., into a physical signal, and converts the physical signal received from the other node into a bit stream. Convert to

The storage unit 6-40 stores data such as a basic program, an application program, and setting information for the operation of the base station. In particular, the storage unit 6-40 may store information on bearers allocated to the connected terminal, measurement results reported from the connected terminal, and the like. In addition, the storage unit 6-40 may store information that is a criterion for determining whether to provide or stop providing multiple connections to the terminal. In addition, the storage unit 6-40 provides stored data according to the request of the control unit 6-50.

The controller 6-50 controls overall operations of the base station. For example, the control unit 6-50 transmits and receives signals through the baseband processing unit 6-20 and the RF processing unit 6-10 or through the backhaul communication unit 6-30. In addition, the control unit 6-50 writes and reads data in the storage unit 6-40. To this end, the controller 6-50 may include at least one processor. In addition, the controller 6-50 may control an operation of a base station or an entity corresponding thereto according to various embodiments of the present disclosure.

In the existing SRB3, only the measurement report, failure report, and RRCReconfigurationComplete message can be transmitted. In the embodiment of the present invention, in the split SRB3, not only the above RRC message but also an additional ULTransfer message can be transmitted. This message is a new RRC message and can be used for transmitting an encapsulated UE RRC message or an F1AP message.

If the UE RRC encapsulates, the following three messages may be encapsulated.

- RRC messages can encapsulate the following 3 types of messages

>> NAS message

>> FIAP

>> The terminal selects and transmits an appropriate container according to the type of message to encapsulate (conventionally, only NAS containers exist)

In the method proposed in the embodiment of the present invention, F1-AP traffic that controls the distributed unit (DU) part of the IAB node is through a dedicated container of the RRC layer, which is the control signal layer of the mobile termination (MT) part of the same IAB node. It can be delivered to the RRC layer of the connected IAB donor node through the RRC PDU.

In addition, in this case, the RRC PDU including the F1-AP may be transmitted through a dedicated RRC message carrying UL traffic of the F1-AP, and the F1-AP DL traffic transmitted from the RRC of the corresponding IAB donor node is dedicated. It can be transmitted from a donor node to a corresponding IAB node through an RRC message.

In various embodiments of the present invention, a corresponding UL dedicated RRC message and a DL dedicated RRC message may be transmitted between an IAB donor and a specific IAB node through SRB3 and split SRB 3.

In the process of creating the split SRB3, there may be a process in which the MN directly requests the establishment of the split SRB3 from the SN, and the SN confirms the establishment of the split SRB3 and transmits it back to the MN.

In the following FIG. 7, DU and MT may be objects included in one IAB node.

When the first MT attempts to access the LTE eNB as an MN, it requests a connection request including rach operation. When the eNB receives the connection request, the eNB may obtain information (eg, T-MSI) corresponding to the UE ID of the UE and transmit it to the MME or subscription management entity of the core network (CN). The corresponding entity (MME and/or subscription management entity) confirms that this terminal is an IAB MT as internal subscription information, and if confirmed, confirms that it is an IAB MT to the eNB and transmits it. For example, the CN entity may transmit to the eNB by setting an indicator indicating that the IAB MT or a new information field indicating the same.

The eNB that has received the information indicating that the terminal is the IAB MT from the CN entity, the frequency information and node information of the gNB that can be used through the X2 interface to identify the gNB capable of IAB operation in the vicinity (can be referred to as gNB-related information) Receive. The eNB may deliver the measurement configuration for the NR frequency to the UE based on information related to the gNB capable of IAB operation.

The UE may perform measurement on the NR frequency based on the measurement configuration received from the eNB, and may transmit measurement information to the eNB. Based on the measurement information received from the UE, the eNB may select an NR gNB corresponding to the SgNB to determine SN addition and perform the SN addition procedure. In this process, the eNB may transmit an SN addition request message to the selected gNB. The SN addition request message may include configuration information of the corresponding MT and an indicator requesting split SRB3 establishment. In this case, the eNB may send this request after it has already determined that it is possible to establish an MCG RLC channel or bearer to be used for split SRB3. Upon receiving the SN addition request message, the gNB determines whether it is possible to establish split SRB3, and can transmit the result back to the eNB. The gNB may transmit an SN addition request ack message including the determination result. At this time, possible information can be transmitted including information on whether only SRB3 can be established, whether split SRB3 can be established, or whether SRB3 itself can be established at all.

As an example, the type of split SRB currently requested in the SgNB addition request message may include the type of srb3, or srb1&3, or srb 2&3, or srb 1&2&3 as follows.

[Table 1]

In the corresponding SgNB addition request acknowledge message, as response information on the type of split srb received, information on the type of the accepted split srb may be transmitted including srb3 or srb1&3, or srb 2&3, or srb 1&2&3. The following shows the SgNB addition request acknowledge message reflecting the above contents.

[Table 2]

When the gNB sends the information as shown in Table 2 to the eNB, it may include radio bearer configuration information to be used for split SRB 3 and secondary cell group (SCG) RLC channel configuration information.

When the eNB receives the SgNB addition request acknowledge message, it may transmit an LTE RRCConnectionReconfiguration message including MCG RLC channel configuration information of split SRB3 to the UE. At this time, the NR RRC reconfiguration message may be encapsulated and delivered to this message, and the radio bearer configuration information and SCG RLC channel configuration information of the split SRB3 transmitted by the gNB may be attached to the encapsulated part. Upon receiving the information, the UE establishes srb3 and establishes an MCG RLC channel corresponding to split SRB3. The SRB3 configuration information may include PDCP configuration information associated with SRB3. The PDCP configuration information may include configuration information on which RLC channel to use. The UE may configure PDCP for split SRB3 based on the PDCP configuration information.

After the UE establishes the split SRB3, if the F1-AP message is transmitted from the DU, after including the corresponding F1-AP data in the dedicated part of the RRC of the MT, the F1-AP message is sent to the RRC message according to the configuration information of the PDCP. Can be transmitted with.

In another embodiment, referring to FIG. 8, in a situation in which SgNB is added to the terminal without the presence of split srb3 already, when additionally requesting the eNB to configure split SRB3 according to the determination of the SN, the eNB is the mcg part of the split srb3. In this case, the user determines and responds to and instructs the terminal to set up.

When the first MT attempts to access the LTE eNB as an MN, it requests a connection request including rach operation. When the eNB receives the connection request, the eNB may obtain information (eg, T-MSI) corresponding to the UE ID of the UE and transmit it to the MME or subscription management entity of the core network. The corresponding entity (MME and/or subscription management entity) confirms that this terminal is an IAB MT as internal subscription information, and if confirmed, confirms that it is an IAB MT to the eNB and transmits it. For example, the CN entity may transmit to the eNB by setting an indicator indicating that the IAB MT or a new information field indicating the same.

The eNB that has received the information indicating that the terminal is the IAB MT from the CN entity, the frequency information and node information of the gNB that can be used through the X2 interface to identify the gNB capable of IAB operation in the vicinity (can be referred to as gNB-related information) Receive. The eNB may deliver the measurement configuration for the NR frequency to the UE based on information related to the gNB capable of IAB operation.

The UE may perform measurement on the NR frequency based on the measurement configuration received from the eNB, and may transmit measurement information to the eNB. Based on the measurement information received from the UE, the eNB may select an NR gNB corresponding to the SgNB to determine SN addition and perform the SN addition procedure.

The eNB may transmit an SN addition request message to the selected gNB. The SN addition request message may include configuration information of the corresponding MT. Through this, the gNB can determine whether to add itself as an SN. The gNB may transmit a response message including the determination result to the eNB. If it is decided to add, the gNB may be referred to as sgNB hereinafter. The response message may be an SN addition request acknowledge. If necessary, the SgNB may establish SRB3 and transmit an NR RRC message including SRB3 setup information to the eNB.

Upon receiving the SN addition request acknowledge and the information contained therein, the eNB may transmit the LTE RRCconnectionReconfiguration message including the configuration information of the corresponding LTE RRC and the NR RRC configuration information created by the SgNB to the UE. If the SN decides to establish SRB3 and delivers the configuration information to the NR RRC message, the UE may establish SRB3 based on this information.

After that, if the gNB decides to establish split SRB3, the gNB may send split SRB3 request information to the eNB. In this process, the gNB may request the eNB to establish the MCG RLC channel/bearer part of split SRB3 by using the SN modification required message.

As an example, the type of split SRB currently requested in the SgNB modification required message can be delivered by including the type of srb3, srb1&3, or srb 2&3, or srb 1&2&3 as follows. In addition, when the eNB decides to establish split SRB3 in this message, the PDCP information of SRB3 and SCG RLC configuration information to be used are also included and transmitted to the eNB through an NR RRC message.

[Table 3]

When the eNB receives this message, it determines the establishment of the MCG RLC bearer of the split SRB3, and if it decides to establish, it delivers the corresponding MCG RLC channel / bearer configuration information to the terminal. At this time, the MCG RLC channel / bearer addition configuration information may be delivered to the terminal through the LTE RRCconnectionReconfiguration message. Along with this, the PDCP configuration information and SCG RLC configuration information of SRB3 sent by the SgNB in the NR RRC message may also be encapsulated in the NR part in the LTE RRCconnectionReconfiguation message and transmitted. The MCG RLC channel information may be SRB index to be linked and RLC configuration information.

The UE receiving the LTE message may establish SRB3 using the PDCP configuration information and SCG RLC channel information of SRB3 included in the NR RRC message. In addition, the MCG RLC channel used in the split part of SRB3 included in the LTE RRC message part is linked to SRB3 to add an MCG RLC channel, and an RLC channel is established based on the RLC configuration information. Through this, a split SRB3 can be established. In this case, the PDCP configuration information given from the SgNB may include configuration information on which RLC channel is to be used among MCG/SCG RLC.

If the UE receives the LTE RRC message and succeeds in establishing split SRB3, it may transmit an LTE RRCconnectionReconfigurationComplete message to the eNB. When the eNB receives this message, it may transmit the NR RRC reconfiguration complete message to the SgNB again. When delivering this NR RRC message, the RRC message can be delivered using the SgNB modification confirm message as an X2 message. At this time, the SgNB modification configm message may include an indicator of success of establishing split srb3.

After the UE establishes the split SRB3, when the F1-AP message is transmitted from the DU, after including the corresponding F1-AP data in the dedicated part of the RRC of the MT, the bearer selected among MCG/SCG bearers according to the configuration information of the PDCP Transfer to.

7 or 8, when the eNB receives information about the split srb3 from the SgNB and transmits the information to the UE as an LTE RRCConnectionReconfiguration message, the SgNB through the PDCP configuration information of split srb3 included in the NR part of the message It is possible to set which RLC channel / bearer to transmit F1-AP data through. That is, an indicator of whether to use the MCG or SCG bearer of srb3 may be given as PDCP configuration information. Alternatively, an indicator of whether to use the primary path or secondary path of split srb3 can be given as PDCP configuration information.

In another embodiment, by setting the UL-DataSplitThreshold value, when the data size of the buffer is larger than the threshold value, the first path of the primary path or the secondary path may be used. If the size is smaller than the threshold, only the primary path of split srb3 can be used. In this case, the NR RRC may determine the primary path as the SCG path or the MCG. If the primary path is determined as SCG, the pdcp data split threshold value is a default value, and 0 can be given. In this case, the F1-AP traffic may be transmitted through a path receiving the UL grant first among MCG or SCG RLC bearer. If the primary path is determined as MCG, infinity can be given using the pdcp data split threshold value as the default value. In this case, F1-AP traffic can be delivered only through the MCG path.

As another method, the primary path of split srb3 is determined as SCG, and in the case of UL data split threshold _ SRB3, the definition is sent to the secondary path when the data size of the buffer is smaller than the threshold value, and if it is larger than the threshold value, the primary path It can be configured to use the path that received the UL grant first among the secondary paths. If the default setting value is an infinity value, F1-AP traffic can always be transmitted through a secondary path, that is, an MCG link. Of course, the default threshold values can be any value depending on the implementation of the network. As another method, the NR RRC may indicate a primary path, a secondary path, and bidirectional transmission (in this case, a path to which the UL grant comes first is used) through PDCP configuration.

As another method, the UE can transmit the F1-AP traffic in a good direction by determining the quality of both MCG/SCG links regardless of the configuration in the PDCP.

If the primary path of split srb3 has CG failure (MCG or SCG failure) including link failure, the UE can itself change the primary path to another path in which no failure has occurred.

In addition, the embodiments disclosed in the present specification and drawings are merely provided specific examples for easy explanation and understanding of the present invention, and are not intended to limit the scope of the present invention. Therefore, the scope of the present invention should be construed that all changes or modified forms derived based on the technical features of the present invention in addition to the embodiments disclosed herein are included in the scope of the present invention.

Claims (1)

In the control signal processing method in a wireless communication system,
Receiving a first control signal transmitted from a base station;
Processing the received first control signal; And
And transmitting a second control signal generated based on the processing to the base station.

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