Method and device for securing base station resiliency in wireless communication system

Abstract

When a failure occurs in a specific DU of a base station or when a change in a device or software is required for the specific DU, interruption of a communication and a service provided by the specific DU may occur. In order to prevent such service interruption, it is necessary to secure base station resiliency. Accordingly, the present specification proposes embodiments related to a method and a device for securing base station resiliency in a wireless communication system.

Description

Method and device for securing base station resiliency in wireless communication systems

[0001] The present invention relates to wireless communications, and more particularly, to a method and device for securing base station resiliency in a wireless communications system.

[0002] As the importance of wireless communications increases with the proliferation of smart devices, the impact of wireless communication service disruptions is also growing. To address this, ongoing discussions are underway on operational automation, including automatic network recovery, such as with Self-Organizing Networks (SON). One of the challenges in implementing automatic recovery for base station equipment can be attributed to the limitations of the fronthaul configuration, which links DUs and RUs. Existing LTE and previous generations of fronthaul were configured with 1:1 connections between DU ports and RU ports, rather than a network configuration. However, starting with 5G, the fronthaul interface utilizes general-purpose network technologies such as Ethernet and IP / UDP, allowing multiple DUs and RUs to be interconnected through a fronthaul network utilizing switches or routers.

[0003] If a specific DU experiences a failure, or if a device or software change is required for that DU, services and communications provided by that DU may be interrupted. To prevent such service interruptions, base station resiliency must be ensured.

[0004] According to one embodiment, a method performed by a base station in a wireless communication system is proposed, the method comprising: receiving configuration information from a management system, wherein the configuration information includes at least a part of an eAxC (extended Antenna-Carrier) identifier, an AxC (Antenna Carrier) identifier, and address information of a first DU (Distributed Unit) utilized for connection of a first RU (Radio Unit), and performing a fronthaul connection between a second DU and the first RU based on the configuration information, wherein the base station includes the first DU, the second DU, and the first RU, and the second DU is a spare DU without an RU connected before the fronthaul connection with the first RU.

[0005] Here, the above configuration information can be transmitted via a management plane message.

[0006] Here, the base station receives a state transition message from the management system, and based on the management system, the base station transitions the state of the first DU to a standby state and transitions the state of the second DU to an active state, and the base station can perform a fronthaul connection between the second DU in the active state and the first RU.

[0007] Here, before the base station receives the configuration information and the state transition message, the base station may set the second DU to a standby state, and the base station may transmit a standby message to the management system.

[0008] Here, the state transition message may be transmitted in response to the waiting message.

[0009] Here, the standby message may include at least some of a first indicator indicating whether the spare DU exists within the base station, a second indicator indicating a status of the spare DU, and a third indicator indicating whether the spare DU is in an activatable standby state.

[0010] According to another embodiment, a base station is provided, comprising: one or more memories storing commands; one or more transceivers; and one or more processors connecting the one or more memories and the one or more transceivers, wherein the one or more processors execute the commands to receive configuration information from a management system, wherein the configuration information includes at least a portion of an eAxC (extended Antenna-Carrier) identifier of a first DU (Distributed Unit) utilized for connection of a first RU (Radio Unit), an AxC (Antenna Carrier) identifier, and address information of the first RU, and performs a fronthaul connection between a second DU and the first RU based on the configuration information, wherein the base station includes the first DU, the second DU, and the first RU, and wherein the second DU is a spare DU that has no RU connected before the fronthaul connection with the first RU.

[0011] Here, the above configuration information can be transmitted via a management plane message.

[0012] Here, the base station receives a state transition message from the management system, and based on the management system, the base station transitions the state of the first DU to a standby state and transitions the state of the second DU to an active state, and the base station can perform a fronthaul connection between the second DU in the active state and the first RU.

[0013] Here, before the base station receives the configuration information and the state transition message, the base station may set the second DU to a standby state, and the base station may transmit a standby message to the management system.

[0014] Here, the state transition message may be transmitted in response to the waiting message.

[0015] Here, the standby message may include at least some of a first indicator indicating whether the spare DU exists within the base station, a second indicator indicating a status of the spare DU, and a third indicator indicating whether the spare DU is in an activatable standby state.

[0016] According to another embodiment, a device is proposed, comprising at least one computer-readable medium comprising instructions that are executed by at least one processor for controlling a base station, the device being configured to receive configuration information from a management system, wherein the configuration information includes at least a portion of an eAxC (extended Antenna-Carrier) identifier of a first DU (Distributed Unit) utilized for connection of a first RU (Radio Unit), an AxC (Antenna Carrier) identifier, and address information of the first RU, and wherein the device is configured to perform a fronthaul connection between a second DU and the first RU based on the configuration information, wherein the base station includes the first DU, the second DU, and the first RU, and the second DU is a spare DU that has no RU connected before the fronthaul connection with the first RU.

[0017] Here, the above configuration information can be transmitted via a management plane message.

[0018] Here, the recording medium is configured such that the base station receives a state transition message from the management system, and based on the management system, the recording medium is configured such that the base station transitions the state of the first DU to a standby state and transitions the state of the second DU to an active state, and the recording medium can be configured such that the base station performs a fronthaul connection between the second DU in the active state and the first RU.

[0019] Here, before the base station receives the configuration information and the state transition message, the recording medium may be configured to cause the base station to set the second DU to a standby state, and the recording medium may be configured to cause the base station to transmit a standby message to the management system.

[0020] Here, the state transition message may be transmitted in response to the waiting message.

[0021] Here, the standby message may include at least some of a first indicator indicating whether the spare DU exists within the base station, a second indicator indicating a status of the spare DU, and a third indicator indicating whether the spare DU is in an activatable standby state.

[0022] According to this specification, it is possible to automatically respond to a failure of base station equipment corresponding to a DU by using spare DU resources, and provide continuous service without service interruption.

[0023] The effects that can be achieved through specific examples of this specification are not limited to the effects listed above. For example, a person with ordinary skill in the relevant technical field may understand or derive various technical effects from this specification. Accordingly, the specific effects of this specification are not limited to those explicitly described herein, but may include various effects that can be understood or derived from the technical features of this specification.

[0024] The following drawings are intended to illustrate specific examples of the present specification. The names of specific devices and the names of specific signals, messages, and fields depicted in the drawings are provided for illustrative purposes only, and the technical features of this specification are not limited to the specific names used in the drawings.

[0025] FIG. 1 illustrates an example of a wireless communication system to which embodiments of the present specification can be applied.

[0026] FIG. 2 illustrates an example of a front-hole interface to which embodiments of the present specification may be applied.

[0027] FIG. 3 illustrates an example of a fronthaul interface of an open (O)-RAN (radio access network) to which embodiments of the present specification can be applied.

[0028] Figure 4 illustrates the functional configuration of a distributed unit (DU) to which embodiments of the present specification can be applied.

[0029] FIG. 5 illustrates an example of a functional configuration of a radio unit (RU) to which embodiments of the present specification can be applied.

[0030] Figure 6 illustrates an example of function split between DU and RU to which embodiments of the present specification may be applied.

[0031] Figure 7 illustrates an example of an option for functional separation to which embodiments of the present specification may be applied.

[0032] FIG. 8 illustrates an example of a configuration of a Distributed Unit (DU), a Radio Unit (RU), and a management system to which embodiments of the present specification can be applied.

[0033] Figure 9 illustrates an example of a method for securing base station resiliency to which embodiments of the present specification can be applied.

[0034] FIG. 10 is a flowchart illustrating an example of a method for securing base station resiliency to which embodiments of the present specification can be applied.

[0035] FIG. 11 is a flowchart of another example of a method for securing base station resiliency to which embodiments of the present specification can be applied.

[0036] FIG. 12 is a flowchart of an example of a method performed by a base station to which embodiments of the present specification can be applied.

[0037] The present invention is susceptible to various modifications and embodiments. Specific embodiments are illustrated in the drawings and described in detail in the detailed description. However, this is not intended to limit the present invention to specific embodiments, but rather to encompass all modifications, equivalents, and alternatives falling within the spirit and technical scope of the present invention. Throughout the description of each drawing, similar reference numerals have been used to designate similar components.

[0038] Although the terms "first," "second," "A," "B," etc. may be used herein to describe various components, the components should not be limited by these terms. These terms are used solely to distinguish one component from another. For example, without departing from the scope of the present invention, the first component could be referred to as the second component, and similarly, the second component could also be referred to as the first component. Furthermore, the term "and / or" includes any combination of multiple related listed items or any one of multiple related listed items.

[0039] When a component is referred to as being "connected" or "connected" to another component, it should be understood that it may be directly connected or connected to that other component, but that there may be other components intervening. Conversely, when a component is referred to as being "directly connected" or "connected" to another component, it should be understood that there are no other components intervening.

[0040] The terminology used herein is for the purpose of describing specific embodiments only and is not intended to limit the present invention. The singular expression includes the plural expression unless the context clearly indicates otherwise. In this specification, it should be understood that the terms "comprises" or "has" indicate the presence of a feature, number, step, operation, component, part, or combination thereof described in the specification, but do not exclude in advance the possibility of the presence or addition of one or more other features, numbers, steps, operations, components, parts, or combinations thereof.

[0041] Unless otherwise defined, the terms used herein, including technical or scientific terms, have the same meanings commonly understood by those of ordinary skill in the art to which the present invention pertains. Terms defined in commonly used dictionaries should be interpreted as having meanings consistent with their meanings within the context of the relevant technology, and will not be interpreted in an idealized or overly formal sense unless explicitly defined herein.

[0042] Hereinafter, a preferred embodiment according to the present invention will be described in detail with reference to the attached drawings.

[0043] Although this specification describes various embodiments using terms used in some communication standards (e.g., 3rd Generation Partnership Project (3GPP), extensible radio access network (xRAN), open-radio access network (O-RAN), etc.), these are merely examples for explanation. Various embodiments of the present disclosure can be easily modified and applied to other communication systems.

[0044] FIG. 1 illustrates an example of a wireless communication system to which embodiments of the present specification can be applied.

[0045] Referring to FIG. 1, FIG. 1 illustrates a base station (110) and a terminal (120) as some of the nodes utilizing a wireless channel in a wireless communication system. Although FIG. 1 illustrates only one base station, the wireless communication system may further include other base stations identical or similar to the base station (110).

[0046] A base station (110) is a network infrastructure that provides wireless access to a terminal (120). The base station (110) has coverage defined based on the distance at which a signal can be transmitted. In addition to a base station, the base station (110) may be referred to as an access point (AP), an eNodeB (eNB), a 5th generation node, a next generation nodeB (gNB), a wireless point, a transmission / reception point (TRP), or other terms having equivalent technical meanings. In addition, the base station (110) may also mean a base station of a next-generation wireless communication system after 5G.

[0047] The terminal (120) is a device used by a user and communicates with the base station (110) via a wireless channel. The link from the base station (110) to the terminal (120) is referred to as a downlink (DL), and the link from the terminal (120) to the base station (110) is referred to as an uplink (UL). In addition, although not shown in FIG. 1, the terminal (120) and another terminal may communicate with each other via a wireless channel. In this case, the link between the terminal (120) and another terminal (device-to-device link, D2D) is referred to as a sidelink, and the sidelink may be used interchangeably with the PC5 interface. In some other embodiments, the terminal (120) may be operated without the involvement of a user. In one embodiment, the terminal (120) is a device that performs machine type communication (MTC) and may not be carried by the user. Additionally, according to one embodiment, the terminal (120) may be an NB (narrowband)-IoT (internet of things) device.

[0048] The terminal (120) may be referred to as a user equipment (UE), a customer premises equipment (CPE), a mobile station, a subscriber station, a remote terminal, a wireless terminal, an electronic device, a user device, or other terms having an equivalent technical meaning.

[0049] The base station (110) can perform beamforming with the terminal (120). The base station (110) and the terminal (120) can transmit and receive wireless signals in a relatively low frequency band (e.g., FR 1 (frequency range 1) of NR). In addition, the base station (110) and the terminal (120) can transmit and receive wireless signals in a relatively high frequency band (e.g., FR 2 (or, FR 2-1, FR 2-2, FR 2-3), FR 3 of NR), millimeter wave (mmWave) band (e.g., 28 GHz, 30 GHz, 38 GHz, 60 GHz, etc.)). To improve channel gain, the base station (110) and the terminal (120) can perform beamforming. Here, the beamforming can include transmission beamforming and reception beamforming. The base station (110) and the terminal (120) can impart directionality to the transmitted or received signal. To this end, the base station (110) and the terminal (120) can select serving beams through a beam search or beam management procedure. After the serving beams are selected, subsequent communication can be performed through resources that have a QCL relationship with the resource that transmitted the serving beams.

[0050] If large-scale characteristics of a channel carrying a symbol on a first antenna port can be inferred from a channel carrying a symbol on a second antenna port, the first antenna port and the second antenna port can be evaluated to have a QCL relationship. For example, the large-scale characteristics may include at least one of delay spread, Doppler spread, Doppler shift, average gain, average delay, and a spatial receiver parameter.

[0051] Although both the base station (110) and the terminal (120) are described as performing beamforming in FIG. 1, the embodiments of the present disclosure are not necessarily limited thereto. In some embodiments, the terminal may or may not perform beamforming. Furthermore, the base station may or may not perform beamforming. That is, either only one of the base station and the terminal may perform beamforming, or neither the base station nor the terminal may perform beamforming.

[0052] In this specification, a beam refers to a spatial flow of a signal in a wireless channel, and is formed by one or more antennas (or antenna elements), and this forming process may be referred to as beamforming. Beamforming may include at least one of analog beamforming and digital beamforming (e.g., precoding). Reference signals transmitted based on beamforming may include, for example, a demodulation-reference signal (DM-RS), a channel state information-reference signal (CSI-RS), a synchronization signal / physical broadcast channel (SS / PBCH), and a sounding reference signal (SRS). In addition, as a configuration for each reference signal, an IE such as a CSI-RS resource or an SRS-resource may be used, and this configuration may include information associated with the beam. Information associated with a beam may mean whether the configuration (e.g., a CSI-RS resource) uses the same spatial domain filter as another configuration (e.g., another CSI-RS resource within the same CSI-RS resource set) or a different spatial domain filter, or whether it is quasi-co-located (QCL) with a reference signal, and if so, what type it is (e.g., QCL type A, B, C, D).

[0053] In the past, in communication systems with relatively large cell radius of base stations, each base station was installed to include the functions of a digital processing unit (or distributed unit (DU)) and a radio frequency (RF) processing unit (or radio unit (RU)). However, as higher frequency bands are used in 4G (4th generation) and / or subsequent communication systems (e.g., 5G) and the cell coverage of base stations becomes smaller, the number of base stations to cover a specific area has increased. The burden of installation costs on operators for installing base stations has also increased. In order to minimize the installation cost of base stations, a structure has been proposed in which the DU and RU of a base station are separated, one or more RUs are connected to one DU via a wired network, and one or more RUs are geographically distributed to cover a specific area. Hereinafter, base station deployment structures and expansion examples according to various embodiments of the present disclosure are described.

[0054] FIG. 2 illustrates an example of a fronthaul interface to which embodiments of the present disclosure may be applied. Unlike the backhaul between a base station and a core network, fronthaul refers to the entity between a wireless LAN and a base station. FIG. 2 illustrates an example of a fronthaul structure between a DU (210) and one RU (220), but this is merely for convenience of explanation and the present disclosure is not limited thereto. In other words, embodiments of the present disclosure may also be applied to a fronthaul structure between one DU and multiple RUs and / or a fronthaul structure between multiple DUs and multiple RUs. For example, embodiments of the present disclosure may be applied to a fronthaul structure between one DU and two RUs. Furthermore, embodiments of the present disclosure may also be applied to a fronthaul structure between one DU and three RUs.

[0055] Referring to FIG. 2, the base station (110) may include a DU (210) and an RU (220). A fronthaul (215) between the DU (210) and the RU (220) may be operated via an Fx interface. For the operation of the fronthaul (215), an interface such as an enhanced common public radio interface (eCPRI) or radio over ethernet (ROE) may be used, for example.

[0056] As communications technology advances, mobile data traffic increases, significantly increasing the bandwidth requirements for the fronthaul between the digital unit and the radio unit. In deployments such as C-RAN (centralized / cloud radio access network), the DU performs functions for the packet data convergence protocol (PDCP), radio link control (RLC), media access control (MAC), and physical layer (PHY), while the RU can be implemented to perform additional functions for the PHY layer in addition to its radio frequency (RF) functions.

[0057] The DU (210) may be responsible for upper layer functions of a wireless network. For example, the DU (210) may perform functions of the MAC layer and a part of the PHY layer. Here, a part of the PHY layer refers to functions performed at a higher level among the functions of the PHY layer, and may include, for example, channel encoding (or channel decoding), scrambling (or descrambling), modulation (or demodulation), and layer mapping (or layer demapping). According to an embodiment, if the DU (210) complies with the O-RAN standard, it may be referred to as an O-DU (O-RAN DU). The DU (210) may be replaced with a first network entity for a base station (e.g., gNB) in embodiments of the present disclosure, if necessary.

[0058] The RU (220) may be responsible for lower layer functions of a wireless network. For example, the RU (220) may perform a part of the PHY layer, an RF function. Here, a part of the PHY layer refers to functions of the PHY layer that are performed at a relatively lower level than the DU (210), and may include, for example, iFFT transformation (or FFT transformation), CP insertion (or CP removal), and digital beamforming. An example of such specific functional separation is described in detail in FIG. 6. The RU (220) may be referred to as an access unit (AU), an access point (AP), a transmission / reception point (TRP), a remote radio head (RRH), a radio unit (RU), or other terms having equivalent technical meanings thereto. According to one embodiment, if the RU (220) complies with the O-RAN standard, it may be referred to as an O-RU (O-RAN RU). RU (220) may be replaced with a second network entity for a base station in embodiments of the present disclosure as needed.

[0059] Although FIG. 2 illustrates that the base station (110) includes a DU (210) and a RU (220), the embodiments of the present disclosure are not limited thereto. The base station according to the embodiments may be implemented in a distributed deployment according to a centralized unit (CU) configured to perform functions of upper layers of an access network (e.g., packet data convergence protocol (PDCP), radio resource control (RRC)) and a distributed unit (DU) configured to perform functions of lower layers. At this time, the distributed unit (DU) may include the digital unit (DU) and radio unit (RU) of FIG. 1. Between a core (e.g., 5GC (5G core) or NGC (next generation core)) network and a radio network (RAN), the base station may be implemented in a structure in which the CU, DU, and RU are arranged in that order. The interface between the CU and the distributed unit (DU) may be referred to as an F1 interface.

[0060] A centralized unit (CU) can be connected to one or more DUs and can be responsible for functions at a higher layer than the DU. For example, the CU can be responsible for functions at the RRC (radio resource control) and PDCP (packet data convergence protocol) layers, while the DU and RU can be responsible for functions at lower layers. The DU can perform some functions (high PHY) of the RLC (radio link control), MAC (media access control), and PHY (physical) layers, while the RU can be responsible for the remaining functions (low PHY) of the PHY layer. In addition, for example, a digital unit (DU) can be included in a distributed unit (DU) depending on the implementation of a distributed deployment of the base station. Hereinafter, unless otherwise defined, the operations of DU (digital unit) and RU are described, but various embodiments of the present disclosure can be applied to both a base station arrangement including a CU and an arrangement in which the DU is directly connected to the core network (i.e., a base station in which the CU and DU are integrated into one entity (e.g., an NG-RAN node)).

[0061] Figure 3 illustrates an example of a fronthaul interface of an open (O)-RAN (radio access network) to which embodiments of the present disclosure may be applied. As a base station (110) according to a distributed deployment, an eNB or gNB may be exemplified.

[0062] Referring to FIG. 3, the base station (110) may include an O-DU (310) and O-RUs (320-1, ..., 320-n). Hereinafter, for convenience of explanation, the operation and function of the O-RU (320-1) may be understood as a description of each of the other O-RUs (e.g., O-RU (320-n)).

[0063] The O-DU (310) is a logical node that includes functions, excluding functions exclusively assigned to the O-RU (320-1), among the functions of the base station according to FIG. 6 described below. The O-DU (310) can control the operation of the O-RUs (320-1, ..., 320-n). The O-DU (310) may be referred to as an LLS (lower layer split) CU (central unit). The O-RU (320-1) is a logical node that includes a subset of the functions of the base station according to FIG. 6 described below. Real-time aspects of control plane (C-plane) communication and user plane (U-plane) communication with the O-RU (320-1) can be controlled by the O-DU (310).

[0064] The O-DU (310) can communicate with the O-RU (320-1) through an LLS interface. The LLS interface corresponds to a fronthaul interface. The LLS interface refers to a logical interface between the O-DU (310) and the O-RU (320-1) that utilizes lower layer functional split (i.e., intra-PHY based functional split). The LLS-C between the O-DU (310) and the O-RU (320-1) provides the C-plane through the LLS interface. The LLS-U between the O-DU (310) and the O-RU (320-1) provides the U-plane through the LLS interface.

[0065] In FIG. 3, entities of the base station (110) are described as O-DU and O-RU to explain the O-RAN. However, these names are not to be construed as limiting the embodiments of the present disclosure. In the embodiments disclosed in this specification, it goes without saying that the operations of the DU (210) of FIG. 2 can be performed by the O-DU (310) of FIG. 3. That is, the description of the DU (210) can be applied to the O-DU (310). Similarly, in the embodiments disclosed in this specification, it goes without saying that the operations of the RU (220) of FIG. 2 can be performed by the O-RU (320-1) of FIG. 3. The description of the RU (220) can be applied to the O-DU (320-1).

[0066] Fig. 4 illustrates the functional configuration of a distributed unit (DU) to which embodiments of the present specification may be applied. The configuration illustrated in Fig. 4 may be understood as the configuration of the DU (210) of Fig. 2 (or the O-DU (310) of Fig. 3) as part of a base station. Terms such as "...unit" and "...unit" used hereinafter refer to a unit that processes at least one function or operation, and may be implemented by hardware, software, or a combination of hardware and software.

[0067] Referring to FIG. 4, DU (210) includes a transceiver (410), memory (420), and processor (430).

[0068] The transceiver (410) can perform functions for transmitting and receiving signals in a wired communication environment. The transceiver (410) can include a wired interface for controlling direct connection between devices via a transmission medium (e.g., copper wire, optical fiber, etc.). For example, the transceiver (410) can transmit an electrical signal to another device via copper wire, or perform conversion between an electrical signal and an optical signal. The DU (210) can communicate with a radio unit (RU) via the transceiver (410). The DU (210) can be connected to a core network or a CU in a distributed arrangement via the transceiver (410).

[0069] The transceiver (410) may perform functions for transmitting and receiving signals in a wireless communication environment. For example, the transceiver (410) may perform a conversion function between a baseband signal and a bit stream according to the physical layer specifications of the system. For example, when transmitting data, the transceiver (410) generates complex symbols by encoding and modulating the transmitted bit stream. In addition, when receiving data, the transceiver (410) restores the received bit stream by demodulating and decoding the baseband signal. In addition, the transceiver (410) may include multiple transmission and reception paths. In addition, according to one embodiment, the transceiver (410) may be connected to the core network or other nodes (e.g., an integrated access backhaul (IAB).

[0070] The transceiver (410) can transmit and receive signals. For example, the transceiver (410) can transmit management plane (M-plane) messages. In addition, the transceiver (410) can transmit management plane (S-plane) messages. In addition, the transceiver (410) can transmit control plane (C-plane) messages. In addition, the transceiver (410) can transmit user plane (U-plane) messages. In addition, the transceiver (410) can receive user plane messages. Although only the transceiver (410) is illustrated in FIG. 4, according to other implementation examples, the DU (210) may include two or more transceivers.

[0071] The transceiver (410) transmits and receives signals as described above. Accordingly, all or part of the transceiver (410) may be referred to as a "communication unit," a "transmitter," a "receiver," or a "transmitter-receiver unit." Furthermore, in the following description, transmission and reception performed via a wireless channel are used to mean that the transceiver (410) performs the processing described above.

[0072] Although not illustrated in FIG. 4, the transceiver (410) may further include a backhaul transceiver for connection to the core network or other base stations. The backhaul transceiver provides an interface for communicating with other nodes within the network. That is, the backhaul transceiver converts a bit stream transmitted from the base station to other nodes, such as other access nodes, other base stations, upper nodes, the core network, etc., into a physical signal, and converts a physical signal received from other nodes into a bit stream.

[0073] The memory (420) stores data such as basic programs, application programs, and setting information for the operation of the DU (210). The memory (420) may be referred to as a storage unit. The memory (420) may be composed of volatile memory, nonvolatile memory, or a combination of volatile memory and nonvolatile memory. In addition, the memory (420) provides stored data upon request from the processor (430).

[0074] The processor (430) controls the overall operations of the DU (210). The processor (430) may be referred to as a control unit. For example, the processor (430) transmits and receives signals through the transceiver (410) (or through the backhaul communication unit). In addition, the processor (430) records and reads data from the memory (420). In addition, the processor (430) may perform the functions of the protocol stack required by the communication standard. Although only the processor (430) is illustrated in FIG. 4, the DU (210) may include two or more processors according to other implementation examples.

[0075] The configuration of DU (210) illustrated in FIG. 4 is merely an example, and examples of DUs performing embodiments of the present disclosure are not limited to the configuration illustrated in FIG. 4. In some embodiments, some configurations may be added, deleted, or changed.

[0076] Fig. 5 illustrates an example of the functional configuration of a radio unit (RU) to which embodiments of the present specification can be applied. The configuration illustrated in Fig. 5 can be understood as a configuration of the RU (220) of Fig. 2 or the O-RU (320-1) of Fig. 3 as part of a base station. Terms such as "... unit" and "... unit" used hereinafter mean a unit that processes at least one function or operation, and this can be implemented by hardware, software, or a combination of hardware and software.

[0077] Referring to FIG. 5, RU (220) includes an RF transceiver (510), a fronthaul transceiver (520), a memory (530), and a processor (540).

[0078] The RF transceiver (510) performs functions for transmitting and receiving signals via a wireless channel. For example, the RF transceiver (510) upconverts a baseband signal into an RF band signal and transmits it via an antenna, and downconverts an RF band signal received via the antenna into a baseband signal. For example, the RF transceiver (510) may include a transmit filter, a receive filter, an amplifier, a mixer, an oscillator, a DAC, an ADC, and the like.

[0079] The RF transceiver (510) may include multiple transmission and reception paths. Furthermore, the RF transceiver (510) may include an antenna unit. The RF transceiver (510) may include at least one antenna array composed of multiple antenna elements. In terms of hardware, the RF transceiver (510) may be composed of digital circuits and analog circuits (e.g., a radio frequency integrated circuit (RFIC)). Here, the digital circuits and analog circuits may be implemented in a single package. In addition, the RF transceiver (510) may include multiple RF chains. The RF transceiver (510) may perform beamforming. The RF transceiver (510) may apply beamforming weights to a signal to be transmitted and received in order to impart directionality to the signal according to the settings of the processor (540). According to one embodiment, the RF transceiver (510) may include an RF (radio frequency) block (or RF unit).

[0080] According to one embodiment, the RF transceiver (510) can transmit and receive signals on a radio access network. For example, the RF transceiver (510) can transmit a downlink signal. The downlink signal can include a synchronization signal (SS), a reference signal (RS) (e.g., a cell-specific reference signal (CRS), a demodulation (DM)-RS), system information (e.g., a MIB, a SIB, remaining system information (RMSI), other system information (OSI)), a configuration message, control information, or downlink data. In addition, for example, the RF transceiver (510) can receive an uplink signal. The uplink signal may include a random access related signal (e.g., a random access preamble (RAP) (or Msg1 (message 1)), Msg3 (message 3)), a reference signal (e.g., a sounding reference signal (SRS), DM-RS), or a power headroom report (PHR). Although only the RF transceiver (510) is illustrated in FIG. 5, according to another implementation example, the RU (220) may include two or more RF transceivers.

[0081] The fronthaul transceiver (520) can transmit and receive signals. According to one embodiment, the fronthaul transceiver (520) can transmit and receive signals on the fronthaul interface. For example, the fronthaul transceiver (520) can receive a management plane (M-plane) message. For example, the fronthaul transceiver (520) can receive a management plane (S-plane) message. For example, the fronthaul transceiver (520) can receive a control plane (C-plane) message. For example, the fronthaul transceiver (520) can transmit a user plane (U-plane) message. For example, the fronthaul transceiver (520) can receive a user plane message. Although only the fronthaul transceiver (520) is illustrated in FIG. 5, according to another implementation example, the RU (220) may include two or more fronthaul transceivers.

[0082] The RF transceiver (510) and the fronthaul transceiver (520) transmit and receive signals as described above. Accordingly, all or part of the RF transceiver (510) and the fronthaul transceiver (520) may be referred to as a "communication unit," a "transmitter," a "receiver," or a "transmitter-receiver unit." In addition, in the following description, transmission and reception performed through a wireless channel are used to mean that the processing described above is performed by the RF transceiver (510).

[0083] The memory (530) stores data such as basic programs, application programs, and setting information for the operation of the RU (220). The memory (530) may be referred to as a storage unit. The memory (530) may be configured as volatile memory, non-volatile memory, or a combination of volatile memory and non-volatile memory. In addition, the memory (530) provides the stored data according to a request from the processor (540). According to one embodiment, the memory (530) may include a memory for conditions, commands, or setting values ​​related to the SRS transmission method.

[0084] The processor (540) controls the overall operations of the RU (220). The processor (540) may be referred to as a control unit. For example, the processor (540) transmits and receives signals through the RF transceiver (510) or the fronthaul transceiver (520). In addition, the processor (540) records and reads data in the memory (530). In addition, the processor (540) may perform functions of a protocol stack required by a communication standard. Although only the processor (540) is illustrated in FIG. 5, the RU (220) may include two or more processors according to other implementation examples. The processor (540) may be a set of instructions or codes stored in the memory (530), and may be a storage space that stores instructions / codes or instructions / codes that are at least temporarily residing in the processor (540), or may be a part of the circuitry that constitutes the processor (540). Additionally, the processor (540) may include various modules for performing communication. The processor (540) may control the RU (220) to perform operations according to the embodiments described below.

[0085] The configuration of RU (220) illustrated in FIG. 5 is merely an example, and examples of RUs performing embodiments of the present disclosure are not limited to the configuration illustrated in FIG. 5. In some embodiments, some configurations may be added, deleted, or changed.

[0086] Figure 6 illustrates an example of function splitting between DUs and RUs to which embodiments of the present disclosure can be applied. As wireless communication technology advances, the frequency bands used have increased further. As the cell radius of a base station has become significantly smaller, the number of RUs required for installation has also increased further. Furthermore, in 5G communication systems, the amount of data transmitted has increased by a factor of up to ten, significantly increasing the transmission capacity of the wired network transmitted to the fronthaul. Due to the factors described above, the installation cost of the wired network in the 5G communication system may increase significantly. Therefore, in order to reduce the transmission capacity of the wired network and the installation cost of the wired network, function splitting can be utilized to transfer some of the functions of the DU's modem to the RU, thereby reducing the transmission capacity of the fronthaul.

[0087] To reduce the burden on the DU, the role of the RU, which is traditionally solely responsible for RF functions, can be expanded to include some physical layer functions. As the RU performs higher-layer functions, its throughput increases, which can increase transmission bandwidth in the fronthaul while reducing latency requirements due to response processing. However, as the RU performs higher-layer functions, virtualization gains decrease, and the RU's size, weight, and cost increase. Considering the trade-offs between the advantages and disadvantages described above, implementing an optimal functional separation is required.

[0088] Referring to Figure 6, the functional separation in the physical layer below the MAC layer is illustrated. For the downlink (DL) that transmits a signal to a terminal through a wireless network, the base station can sequentially perform channel encoding / scrambling, modulation, layer mapping, antenna mapping, RE mapping, digital beamforming (e.g., precoding), iFFT transform / CP insertion, and RF transform. For the uplink (UL) that receives a signal from a terminal through a wireless network, the base station can sequentially perform RF transform, FFT transform / CP removal, digital beamforming (pre-combining), RE demapping, channel estimation, layer demapping, demodulation, and decoding / descrambling. The separation of uplink and downlink functions can be defined in various types depending on the needs of vendors, discussions in standards, etc., according to the above-mentioned trade-offs.

[0089] In the first functional separation (610), the RU performs the RF function, and the DU performs the PHY function. The first functional separation is one in which the PHY function is not substantially implemented in the RU, and may be referred to as Option 8, for example. In the second functional separation (620), the RU performs iFFT conversion / CP insertion in the DL of the PHY function and FFT conversion / CP removal in the UL, and the DU performs the remaining PHY functions. As an example, the second functional separation (620) may be referred to as Option 7-1. In the third functional separation (630), the RU performs iFFT conversion / CP insertion in the DL of the PHY function, FFT conversion / CP removal in the UL, and digital beamforming, and the DU performs the remaining PHY functions. As an example, the third functional separation (630) may be referred to as Option 7-2x Category A. In the fourth functional separation (635), the RU performs up to digital beamforming in both the DL and UL, and the DU performs upper PHY functions after the digital beamforming. For example, the fourth functional separation (635) may be referred to as Option 7-2x Category B. In the fifth functional separation (640), the RU performs up to RE mapping (or RE demapping) in both the DL and UL, and the DU performs upper PHY functions after RE mapping (or RE demapping). For example, the fifth functional separation (640) may be referred to as Option 7-2. In the sixth functional separation (650), the RU performs up to modulation (or demodulation) in both the DL and UL, and the DU performs upper PHY functions after modulation (or demodulation). For example, the sixth functional separation (650) may be referred to as Option 7-3. In the seventh functional separation (660), the RU performs encoding / scrambling (or decoding / descrambling) in both the DL and UL, and the DU performs subsequent upper PHY functions up to modulation (or demodulation). For example, the seventh functional separation (660) may be referred to as Option 6.Options for functional separation can be categorized as shown in Fig. 7. Fig. 7 illustrates an example of options for functional separation to which embodiments of the present specification can be applied.

[0090] In one embodiment, when a large amount of signal processing is expected, such as in the FR 1 MMU, functional separation at a relatively high layer (e.g., the fourth functional separation (635)) may be required to reduce fronthaul capacity. In addition, functional separation at too high a layer (e.g., the sixth functional separation (650)) may complicate the control interface and cause a burden on the implementation of the RU due to the inclusion of a large number of PHY processing blocks within the RU. Therefore, appropriate functional separation may be required depending on the arrangement and implementation method of the DU and the RU.

[0091] In one embodiment, if the DU cannot process precoding of data received from it (i.e., if the RU has limited precoding capability), the third functional separation (630) or a lower functional separation (e.g., the second functional separation (620)) may be applied. Conversely, if the DU has the capability to process precoding of data received from it, the fourth functional separation (635) or a higher functional separation (e.g., the sixth functional separation (650)) may be applied.

[0092] Hereinafter, embodiments in the present disclosure are described based on the third functional separation (630) (which may be referred to as category A (CAT-A)) or the fourth functional separation (635) (which may be referred to as category B (CAT-B)) for performing beamforming processing in an RU unless otherwise specified. The O-RAN standard distinguishes the types of O-RUs depending on whether the precoding function is located at the interface of the O-DU or the O-RU interface. An O-RU that does not perform precoding (i.e., has low complexity) may be referred to as a CAT-A O-RU. An O-RU that performs precoding may be referred to as a CAT-B O-RU.

[0093] Hereinafter, the term "upper-PHY" refers to physical layer processing handled in the DU of the fronthaul interface. For example, the upper-PHY may include FEC encoding / decoding, scrambling, and modulation / demodulation. Hereinafter, the term "lower-PHY" refers to physical layer processing handled in the RU of the fronthaul interface. For example, the lower-PHY may include FFT / iFFT, digital beamforming, PRACH (physical random access channel) extraction, and filtering. However, the above-described criteria do not exclude embodiments through other functional separations. The functional configuration, signaling, or operation of the embodiments of the present specification may be applied not only to the third functional separation (630) or the fourth functional separation (635), but also to other functional separations.

[0094] Embodiments of the present disclosure exemplarily describe the standards of eCPRI and O-RAN as fronthaul interfaces when transmitting messages between a DU (e.g., DU (210) of FIG. 2) and an RU (e.g., RU (220) of FIG. 2). The Ethernet payload of a message may include an eCPRI header, an O-RAN header, and additional fields. Hereinafter, various embodiments of the present disclosure are described using standard terms of eCPRI or O-RAN, but other expressions having equivalent meanings to each term may be used instead in various embodiments of the present disclosure.

[0095] The fronthaul transport protocol can use Ethernet and eCPRI, which are easy to share with networks. The Ethernet payload can include an eCPRI header and an O-RAN header. The eCPRI header can be located at the beginning of the Ethernet payload. The contents of the eCPRI header are as follows.

[0096] 1) ecpriVersion (4 bits): This parameter indicates the eCPRI protocol version.

[0097] 2) ecpriReserved (3 bits): This parameter is reserved for further use by eCPRI.

[0098] 3) ecpriConcatenation (1 bit): This parameter indicates when eCPRI concatenation is in use.

[0099] 4) ecpriMessage (1 byte): This parameter indicates the type of service carried by the message type. For example, the parameter indicates an IQ data message, a real-time control data message, or a transmission network delay measurement message.

[0100] 5) ecpriPayload (2 bytes): This parameter indicates the byte size of the payload portion of the eCPRI message.

[0101] 6) ecpriRtcid / ecpriPcid (2 bytes): This parameter is the eAxC (extended antenna-carrier) identifier (eAxC ID) and identifies a specific data flow associated with each C-plane (ecpriRtcid) or U-plane (ecpriPcid) message.

[0102] 7) ecpriSeqid (2 bytes): This parameter provides unique message identification and ordering at both levels. The first octet of this parameter is a sequence ID used to identify the order of messages within the eAxC message stream. The sequence ID is used to ensure that all messages are received and to reorder out-of-order messages. The second octet of this parameter is a subsequence ID. The subsequence ID is used to ensure ordering and implement reordering when radio-transport-level (eCPRI or IEEE-1914.3) fragmentation occurs.

[0103] The eAxC identifier (ID) includes a band and sector identifier ('BandSector_ID'), a component carrier identifier ('CC_ID'), a spatial stream identifier ('RU_Port_ID'), and a distributed unit identifier ('DU_Port_ID'). The bit allocation of the eAxC ID can be distinguished as follows.

[0104] 1) DU_port ID: The DU_port ID is used to distinguish processing units (e.g., different baseband cards) in the O-DU. The O-DU is expected to allocate bits for the DU_port ID, and the O-RU is expected to attach the same value to the UL U-plane message carrying the same sectionId data.

[0105] 2) BandSector_ID: Aggregated cell identifier (band and sector distinction supported by O-RU).

[0106] 3) CC_ID: CC_ID identifies the carrier component supported by the O-RU.

[0107] 4) RU_port ID: The RU_port ID specifies logical flows such as data layer or spatial streams, and signaling channels that require separate numerologies (e.g., PRACH) or special antenna allocation such as SRS.

[0108] The application protocol of the fronthaul may include a control plane (C-plane), a user plane (U-plane), a synchronization plane (S-plane), and a management plane (M-plane).

[0109] The control plane may be configured to provide scheduling information and beamforming information via control messages. The control plane refers to real-time control between DUs and RUs. The user plane may include IQ sample data transmitted between DUs and RUs. The user plane may include user downlink data (IQ data or SSB / RS), uplink data (IQ data or SRS / RS), or PRACH data. A weight vector of the beamforming information described above may be multiplied by the user's data. The synchronization plane generally refers to traffic between DUs and RUs for a synchronization controller (e.g., IEEE grand master). The synchronization plane may be related to timing and synchronization. The management plane refers to non-real-time control between DUs and RUs. The management plane may be related to initial setup, non-realtime reset or reset, and non-realtime report.

[0110] Control plane messages, or C-plane messages, can be encapsulated based on a two-layer header approach. The first layer can consist of the eCPRI common header or the IEEE 1914.3 common header, which contains fields used to indicate the message type. The second layer is the application layer, which contains fields necessary for control and synchronization. Within the application layer, sections define the characteristics of U-plane data transmitted or received on a beam with a single pattern ID. The following section types are supported within the C-plane:

[0111] Section Type can indicate the purpose of control messages transmitted on the control plane. For example, the purposes of each Section Type are as follows.

[0112] 1) sectionType=0: Used to indicate resource blocks or symbols not used in DL or UL.

[0113] 2) sectionType=1: Used for most DL / UL wireless channels. Here, "most" refers to channels that do not require time or frequency offsets, such as those required for mixed numerology channels.

[0114] 3) sectionType=2: reserved for further use

[0115] 4) sectionType=3: PRACH and mixed-numerology channels. Channels that require a time or frequency offset or differ from the nominal SCS value(s).

[0116] 5) sectionType=4: reserved for further use

[0117] 6) sectionType=5: UE scheduling information. Transmits UE scheduling information so that the RU can perform real-time BF weight calculations (O-RAN optional BF method).

[0118] 7) sectionType=6: Transmits UE-specific channel information. Periodically transmits UE channel information to enable the RU to perform real-time BF weight calculations (O-RAN optional BF method).

[0119] 8) sectionType=7: Used for LAA support

[0120] 9) sectionType=8: Used for ACK / NACK Feedback

[0121] Hereinafter, the method / example / configuration proposed in this specification is described in more detail.

[0122] As the importance of wireless communications increases with the proliferation of smart devices, the impact of wireless communication service disruptions is also growing. To address this, ongoing discussions are underway on operational automation, including automatic network recovery, such as with Self-Organizing Networks (SON). One of the challenges in implementing automatic recovery for base station equipment can be attributed to the limitations of the fronthaul configuration, which links DUs and RUs. Existing LTE and previous generations of fronthaul were configured with 1:1 connections between DU ports and RU ports, rather than a network configuration. However, starting with 5G, the fronthaul interface utilizes general-purpose network technologies such as Ethernet and IP / UDP, allowing multiple DUs and RUs to be interconnected through a fronthaul network utilizing switches or routers. Figure 8 illustrates an example configuration of a DU (Distributed Unit), RU (Radio Unit), and management system to which embodiments of the present disclosure can be applied. Referring to Figure 8, base station equipment for mobile communication services can be operated through a management system for managing base station equipment, with DU and RU interconnected through a fronthaul (or fronthaul network).

[0123] For example, in the configuration of FIG. 8, if a failure occurs for a specific DU, or if a change in the device or software for that specific DU is required, the services and communications provided by that specific DU may be interrupted. To prevent such service interruptions, securing base station resiliency is necessary.

[0124] Accordingly, the present specification proposes a method for configuring a fronthaul between a spare DU and an RU by transmitting information about an RU linked to a specific DU to a spare DU when a failure of a specific DU is detected through a management system in order to secure base station resiliency. In addition, the present specification proposes a method for operating a communication system without service interruption by switching the DU so that the spare DU provides information that was provided through the specific DU when a task affecting the service, such as DU replacement or software change, is required, and performing tasks such as replacing a specific DU or changing the software of a specific DU. In the present specification, the management system may be a device located inside or outside the base station, or may be a module including a processor that executes a command capable of implementing a function of the management system proposed in the present specification and a memory that stores the command.

[0125] Figure 9 illustrates an example of a method for securing base station resiliency to which embodiments of the present specification can be applied.

[0126] Referring to Fig. 9, a plurality of DUs including DU_1 and DU_2 are managed by a management system, and the plurality of DUs are connected to a plurality of RUs such as RU_1, RU_2, etc. via a fronthaul network. Here, as an example, it is assumed that DU_1 is connected to RU_1, and DU_2 is connected to RU_2. When the management system detects a failure of DU_2 or detects / judges the need for DU equipment replacement / software change, the management system can transmit the information necessary for linking RU_2 to a spare DU (DU_spare) and set the spare DU and RU_2 to be linked with each other. Through this, the service previously provided by DU_2 can be continuously provided by the spare DU, and thus, the service continuity of the communication system can be secured.

[0127] Figure 10 is a flowchart illustrating an example of a method for securing base station resiliency to which embodiments of the present disclosure may be applied. Figure 10 assumes a structure in which one RU and one DU within a base station are interconnected, but the example of Figure 10 can also be applied to a structure in which multiple RUs and multiple DUs within a base station are interconnected.

[0128] Referring to Figure 10, a management system generally connected to base station equipment can monitor the status and performance of the base station equipment. Here, a spare DU (DU_spare) is additionally configured in the base station equipment and can be linked to the management system and a fronthaul network.

[0129] Referring to Figure 10, the management system establishes a management plane with a DU, an RU, and a spare DU (DU_spare) (S1010). Here, the management plane refers to non-real-time control between the DU and the RU, and may be related to initial setup, non-realtime reset or reset, non-realtime report, etc.

[0130] In connection with the establishment of the above management plane, each component may exchange management plane messages with each other. For example, the base station equipment may be linked to the management system, and may transmit management plane messages from the DU and DU_spare to the management system. Here, the management plane messages may include basic performance information, fault-related information, etc. of the base station equipment or the DU or RU. In addition, the management plane messages may include at least some of the following information.

[0131] - Information on eAxC (extended antenna-carrier) used for RU and fronthaul interworking

[0132] - RU address (MAC or IP)

[0133] - Indicator for whether DU spare support is provided: Indicates whether DU_spare function is supported (e.g., 1: supported, 0: not supported)

[0134] - DU's spare status indicator: Indicates whether it can be used as a spare DU (e.g., 1: available, 0: not available)

[0135] For example, the management system can determine whether a node is a spare DU, i.e., DU_spare, based on an indicator indicating whether the DU supports spareness. Furthermore, the management system can determine whether a node is currently a usable spare DU, i.e., DU_spare, based on a DU's spare status indicator.

[0136] After the management plane is established, the management system detects a failure of the DU (S1020). Based on the failure detection, the management system can transmit configuration information to the spare DU (S1030). Here, the configuration information may include at least a portion of the eAxC (extended Antenna-Carrier) ID, AxC (Antenna Carrier) ID, and RU address information (MAC address, IP address, VLAN ID, etc.) used for RU linkage.

[0137] Based on the above configuration information, the spare DU and the RU (i.e., the RU linked with the DU where the failure was detected) are fronthaul connected / fronthaul linked (S1040). The spare DU and RU connected to the fronthaul can continuously provide the services provided by the DU and RU where the failure occurred.

[0138] Figure 11 is a flowchart illustrating another example of a method for securing base station resiliency to which embodiments of the present disclosure may be applied. Figure 11 assumes a structure in which one RU and one DU within a base station are interconnected, but the example of Figure 11 can also be applied to a structure in which multiple RUs and multiple DUs within a base station are interconnected.

[0139] Referring to Figure 11, a management system generally connected to base station equipment can monitor the status and performance of the base station equipment. Here, a spare DU (DU_spare) is additionally configured in the base station equipment and can be linked to the management system and a fronthaul network.

[0140] Referring to Fig. 11, the management system establishes a management plane with a DU, an RU, and a spare DU (DU_spare) (S1110). Here, the management plane refers to non-real-time control between the DU and the RU, and may be related to initial setup, non-realtime reset or reset, non-realtime report, etc.

[0141] In connection with the establishment of the above management plane, each component may exchange management plane messages with each other. For example, the base station equipment may be linked to the management system, and may transmit management plane messages from the DU and DU_spare to the management system. Here, the management plane messages may include basic performance information, fault-related information, etc. of the base station equipment or the DU or RU. In addition, the management plane messages may include at least some of the following information.

[0142] - Information on eAxC (extended antenna-carrier) used for RU and fronthaul interworking

[0143] - RU address (MAC or IP)

[0144] - Indicator for whether DU spare support is provided: Indicates whether DU_spare function is supported (e.g., 1: supported, 0: not supported)

[0145] - DU's spare status indicator: Indicates whether it can be used as a spare DU (e.g., 1: available, 0: not available)

[0146] For example, the management system can determine whether a node is a spare DU, i.e., DU_spare, based on an indicator indicating whether the DU supports spareness. Furthermore, the management system can determine whether a node is currently a usable spare DU, i.e., DU_spare, based on a DU's spare status indicator.

[0147] The above management system may transmit configuration information to a spare DU based on the above failure detection (S1120). Here, the configuration information may include at least a portion of the eAxC (extended Antenna-Carrier) ID, AxC (Antenna Carrier) ID, and RU address information (MAC address, IP address, VLAN ID, etc.) used for RU linkage.

[0148] The above-mentioned spare DU applies the above-mentioned configuration information and enters a standby state (S1130). Thereafter, the spare DU transmits a standby message to the management system (S1140). The standby message may include an identifier for the spare DU and information / indicator indicating that the spare DU is in a standby state. Through this, the management system can determine that the spare DU is in a standby state. Here, the standby state may be a state that can be converted to an active state.

[0149] Here, the standby message may be a message indicating the status of multiple DUs within the base station. For example, the standby message may indicate the status of all DUs within the base station. At this time, the standby message may include an indicator indicating whether there is a spare DU (DU_spare) within the base station or whether the spare DU is supported, an indicator indicating the status of the spare DU, an indicator indicating whether the spare DU is in an active standby state, etc.

[0150] The management system transmits a state transition message to the DU and the spare DU (S1150). The state transition message may include at least some of an identifier of the receiving side and a command / indicator / information for changing / switching the state of the receiving side. For example, when there are multiple spare DUs, the state transition message may include an identifier for identifying a specific spare DU among the multiple spare DUs and a command / indicator / information for changing / switching the state. As another example, the state transition message may include only a command / indicator / information for changing / switching the state, and the receiving side that receives the message may change its own state.

[0151] Each of the above DU and the spare DU switches its state based on the state transition message (S1160). Here, the spare DU in the standby state can switch to the active state. Additionally, the DU in the active state can switch to the standby state.

[0152] Based on the above configuration information, the spare DU and the RU (i.e., the RU linked with the DU that has switched to the standby state) are fronthaul connected / fronthaul linked (S1170). The spare DU and RU connected to the fronthaul can continuously provide the services provided by the DU and RU that have switched to the standby state.

[0153] Figure 12 is a flowchart illustrating an example of a method performed by a base station to which embodiments of the present disclosure may be applied. The base station may include a specific DU, a specific RU connected to the specific DU via fronthaul, and a spare DU.

[0154] Referring to Fig. 12, the base station receives configuration information from the management system (S1210). Here, the configuration information may include at least a portion of the eAxC (extended Antenna-Carrier) ID, AxC (Antenna Carrier) ID, and address information (MAC address, IP address, VLAN ID, etc.) of a specific DU used for specific RU linkage and the specific RU. In addition, the configuration information may be information transmitted to the spare DU. In addition, the spare DU may be a DU without a connected RU.

[0155] Although not illustrated in Figure 12, the management system may transmit the configuration information based on a determination of whether the configuration information should be transmitted. For example, the management system may determine that an error has occurred in the specific DU and / or that a spare DU has entered a standby state. At this time, the management system may determine whether the configuration information should be transmitted and transmit the configuration information.

[0156] The base station performs a fronthaul connection between the spare DU and the specific RU based on the configuration information (S1220). Here, the spare DU and the specific RU can provide the service provided by the specific DU and the specific RU.

[0157] The claims set forth in this specification may be combined in various ways. For example, the technical features of the method claims of this specification may be combined to implement a device, and the technical features of the device claims of this specification may be combined to implement a method. Furthermore, the technical features of the method claims and the technical features of the device claims of this specification may be combined to implement a device, and the technical features of the method claims and the technical features of the device claims of this specification may be combined to implement a method. Furthermore, the embodiments set forth in this specification may be combined as long as they are not mutually incompatible.

Claims

1. A method performed by a base station in a wireless communication system, Receive configuration information from the management system, The above configuration information includes at least a part of the eAxC (extended Antenna-Carrier) identifier of the first DU (Distributed Unit) used for connection of the first RU (Radio Unit), the AxC (Antenna Carrier) identifier, and the address information of the first RU, and Based on the above configuration information, a fronthaul connection is performed between the second DU and the first RU, The base station includes the first DU, the second DU, and the first RU, A method characterized in that the second DU is a spare DU that has no RU connected before the fronthaul connection with the first RU.

2. In paragraph 1, A method characterized in that the above configuration information is transmitted via a management plane message.

3. In paragraph 1, The above base station receives a status transition message from the above management system, Based on the above management system, the base station switches the state of the first DU to a standby state and switches the state of the second DU to an active state, A method characterized in that the base station performs a fronthaul connection between the second DU and the first RU in the active state.

4. In paragraph 3, Before the base station receives the configuration information and the state transition message, the base station sets the second DU to a standby state, A method characterized in that the base station transmits a waiting message to the management system.

5. In paragraph 4, A method characterized in that the above state transition message is transmitted in response to the above waiting message.

6. In paragraph 4, A method characterized in that the standby message includes at least some of a first indicator indicating whether the spare DU exists within the base station, a second indicator indicating a status of the spare DU, and a third indicator indicating whether the spare DU is in an active standby state.

7. The base station, One or more memories that store instructions; one or more transmitters and receivers; and One or more processors connecting the one or more memories and the one or more transceivers, wherein the one or more processors execute the instructions, Receive configuration information from the management system, The above configuration information includes at least a part of the eAxC (extended Antenna-Carrier) identifier of the first DU (Distributed Unit) used for connection of the first RU (Radio Unit), the AxC (Antenna Carrier) identifier, and the address information of the first RU, and Based on the above configuration information, a fronthaul connection is performed between the second DU and the first RU, The base station includes the first DU, the second DU, and the first RU, A device characterized in that the second DU is a spare DU without a connected RU before the fronthaul connection with the first RU.

8. In paragraph 7, A device characterized in that the above configuration information is transmitted via a management plane message.

9. In paragraph 7, The above base station receives a status transition message from the above management system, Based on the above management system, the base station switches the state of the first DU to a standby state and switches the state of the second DU to an active state, A device characterized in that the base station performs a fronthaul connection between the second DU and the first RU in the active state.

10. In paragraph 9, Before the base station receives the configuration information and the state transition message, the base station sets the second DU to a standby state, A device characterized in that the base station transmits a waiting message to the management system.

11. In paragraph 10, A device characterized in that the above state transition message is transmitted in response to the above waiting message.

12. In paragraph 10, A device characterized in that the standby message includes at least some of a first indicator indicating whether the spare DU exists within the base station, a second indicator indicating a status of the spare DU, and a third indicator indicating whether the spare DU is in an active standby state.

13. At least one computer-readable recording medium containing instructions based on being executed by at least one processor controlling a base station, configured to receive configuration information from the management system; The above configuration information includes at least a part of the eAxC (extended Antenna-Carrier) identifier of the first DU (Distributed Unit) used for connection of the first RU (Radio Unit), the AxC (Antenna Carrier) identifier, and the address information of the first RU, and It is configured to perform a fronthaul connection between the second DU and the first RU based on the above configuration information, The base station includes the first DU, the second DU, and the first RU, A device characterized in that the second DU is a spare DU without a connected RU before the fronthaul connection with the first RU.

14. In paragraph 13, A device characterized in that the above configuration information is transmitted via a management plane message.

15. In paragraph 13, The above recording medium is configured such that the base station receives a status transition message from the management system, Based on the above management system, the recording medium is configured to cause the base station to switch the state of the first DU to a standby state and switch the state of the second DU to an active state, A device characterized in that the recording medium is configured to enable the base station to perform a fronthaul connection between the second DU and the first RU in the active state.

16. In paragraph 15, Before the base station receives the configuration information and the state transition message, the recording medium is configured to cause the base station to set the second DU to a standby state, A device characterized in that the recording medium is configured to cause the base station to transmit a waiting message to the management system.

17. In paragraph 16, A device characterized in that the above state transition message is transmitted in response to the above waiting message.

18. In paragraph 16, A device characterized in that the standby message includes at least some of a first indicator indicating whether the spare DU exists within the base station, a second indicator indicating a status of the spare DU, and a third indicator indicating whether the spare DU is in an active standby state.

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