Apparatus and method for managing resources of a base station radio unit in a wireless communication system - Patents.com

Abstract

This disclosure relates to 4G (4G) such as LTE (Long Term Evolution). th 5G (5th Generation) communication systems to support higher data transmission rates th The present disclosure relates to a 5G (fifth generation) or pre-5G communication system. The present disclosure relates to a method for managing resources of a radio unit (RU) of a base station, and the method includes transmitting a first message including a value indicating a maximum number of masks for one resource region to a digital unit (DU), and receiving a second message generated based on the value from the DU, and the mask may indicate resources to which the same beam is applied within the resource region.

Description

[Technical field]

[0001] The disclosure relates generally to wireless communication systems, and more particularly to an apparatus and method for managing resources of a radio unit (RU) of a base station in a wireless communication system. [Background technology]

[0002] 4G(4 th Since the commercialization of the 5G (5G) communication system, improved 5G (5G) has been developed to meet the increasing demand for wireless data traffic. th Efforts are being made to develop 5G (Next Generation) or pre-5G communication systems. For this reason, 5G or pre-5G communication systems are referred to as Beyond 4G Network communication systems or Post-LTE (Long Term Evolution) systems.

[0003] To achieve high data transmission rates, 5G communication systems are being considered for implementation in ultra-high frequency (mmWave) bands (e.g., 60 GHz bands, etc.). To mitigate the path loss of radio waves in ultra-high frequency bands and increase the transmission distance of radio waves, beamforming, massive multiple input multiple output (massive MIMO), full dimensional MIMO (FD-MIMO), array antennas, analog beam-forming, and large scale antenna technologies are being discussed for 5G communication systems.

[0004] In addition, to improve the system network, technologies being developed for the 5G communication system include advanced small cell, cloud radio access network (cloud RAN), ultra-dense network, device to device communication (D2D), wireless backhaul, moving network, cooperative communication, coordinated multi-points (CoMP), and receive interference cancellation.

[0005] In addition, advanced coding modulation (ACM) methods such as FQAM (hybrid frequency shift keying and quadrature amplitude modulation) and SWSC (sliding window superposition coding), as well as advanced access technologies such as FBMC (filter bank multi carrier), NOMA (non-orthogonal multiple access), and SCMA (sparse code multiple access) are being developed for the 5G system.

[0006] In 5G systems, function split is being applied to separate base stations functionally in response to the increase in transmission capacity in wireless communication systems. With function split, a base station is separated into a digital unit (DU) and a radio unit (RU), and the RU operates under the control of the DU. Summary of the Invention [Problem to be solved by the invention]

[0007] Based on the above discussion, the present disclosure provides an apparatus and method for effectively controlling a radio unit (RU) of a base station in a wireless communication system.

[0008] The present disclosure also provides an apparatus and method for effectively managing resources of a RU of a base station in a wireless communication system.

[0009] The present disclosure also provides an apparatus and method for preventing memory waste in a RU of a base station in a wireless communication system. [Means for solving the problem]

[0010] According to various embodiments of the present disclosure, a method for operating a radio unit (RU) of a base station in a wireless communication system includes transmitting a first message including a value indicating a maximum number of masks for one resource region to a digital unit (DU), and receiving a second message generated based on the value from the DU, wherein the mask may indicate resources to which the same beam is applied within the resource region.

[0011] According to various embodiments of the present disclosure, a method for operating a DU (digital unit) of a base station in a wireless communication system includes a step of receiving a first message from a RU (radio unit) including a value indicating a maximum number of masks for one resource region, and a step of transmitting a second message generated based on the value to the RU, wherein the mask may indicate resources to which the same beam is applied within the resource region.

[0012] According to various embodiments of the present disclosure, a radio unit (RU) of a base station in a wireless communication system includes a transceiver and at least one processor connected to the transceiver, the at least one processor transmits a first message including a value indicating a maximum number of masks for one resource region to a digital unit (DU), and receives a second message generated based on the value from the DU, the mask indicating resources to which the same beam is applied within the resource region. According to various embodiments of the present disclosure, a radio unit (DU) of a base station in a wireless communication system includes a transceiver and at least one processor connected to the transceiver, the at least one processor receiving a first message including a value indicating a maximum number of masks for one resource region from a radio unit (RU), and transmitting a second message generated based on the value to the RU, the mask indicating resources to which the same beam is applied within the resource region. Effect of the Invention

[0013] Apparatus and methods according to various embodiments of the present disclosure can prevent unnecessary resource waste in a radio unit (RU) of a base station. The effects obtained by the present disclosure are not limited to the effects mentioned above, and other effects not mentioned can be clearly understood by a person having ordinary skill in the technical field to which the present disclosure pertains from the following description. [Brief description of the drawings]

[0014] [Figure 1A] FIG. 1 illustrates a wireless communication system in accordance with various embodiments of the present disclosure. [Figure 1B] A diagram showing an example of a fronthaul structure with functional separation of a base station according to various embodiments of the present disclosure. [Diagram 2] A diagram showing the configuration of a DU (digital unit) in a wireless communication system according to various embodiments of the present disclosure. [Diagram 3] A diagram showing the configuration of a radio unit (RU) in a wireless communication system according to various embodiments of the present disclosure. [Figure 4] FIG. 2 illustrates an example of function split in a wireless communication system according to various embodiments of the present disclosure. [Diagram 5] A diagram showing examples of beams that can be formed by a RU of a base station in a wireless communication system according to various embodiments of the present disclosure. [Figure 6] A figure showing an example of a resource element (RE) mask in a wireless communication system according to various embodiments of the present disclosure. [Figure 7] FIG. 2 illustrates an example memory space for storing mask values ​​in a wireless communication system according to various embodiments of the present disclosure. [Figure 8] 5 is a flowchart illustrating the operation of a RU in a wireless communication system according to various embodiments of the present disclosure. [Figure 9] 4 is a flowchart illustrating the operation of a digital unit (DU) in a wireless communication system according to various embodiments of the present disclosure. [Figure 10] A diagram illustrating signal exchange between a DU and a RU in a wireless communication system according to various embodiments of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] The terms used in this disclosure are merely used to describe certain embodiments and are not intended to limit the scope of other embodiments. A singular expression may include a plural expression unless the context clearly indicates a different meaning. Terms used herein, including technical or scientific terms, may have the same meaning as commonly understood by a person having ordinary skill in the technical field described in this disclosure. Terms used in this disclosure that are defined in a general dictionary may be interpreted as meanings that are the same as or similar to the meanings in the context of the relevant art, and are not interpreted as ideal or overly formal meanings unless clearly defined in this disclosure. In some cases, even terms defined in this disclosure cannot be interpreted to exclude embodiments of the present disclosure.

[0016] In the various embodiments of the present disclosure described below, a hardware approach is described as an example, but since the various embodiments of the present disclosure include techniques using both hardware and software, the various embodiments of the present disclosure do not exclude a software-based approach.

[0017] Hereinafter, the present disclosure relates to an apparatus and method for managing resources of a base station's RU (radio unit), which includes a DU (digial unit) and at least one RU (radio unit) in a wireless communication system. In particular, the present disclosure describes a technique for managing memory resources of a base station's RU in a wireless communication system.

[0018] In the following explanation, the following terms are used: terms referring to signals (e.g., message, information, preamble, signal, signaling, sequence, stream), terms referring to resources (e.g., symbol, slot, subframe, radio frame, subcarrier, resource element (RE), resource block (RB), bandwidth part (BWP), occasion), terms indicating operation states (e.g., step, operation, procedure), terms referring to data (e.g., user stream, IQ data, information, bit, symbol, codeword), terms referring to channels, terms referring to control information (e.g., downlink control information (DCI), medium access control element (CE), radio resource control (RRC) signaling), network entity (NE), The terms referring to a device entity, the terms referring to components of a device, etc. are exemplified for convenience of explanation. Therefore, the present disclosure is not limited to the terms described below, and other terms having equivalent technical meanings may be used.

[0019] In the following description, the terms physical channel and signal may be used interchangeably with data or control signals. For example, PDSCH (physical downlink shared channel) is a term that refers to a physical channel through which data is transmitted, but PDSCH may also be used to refer to data. That is, in this disclosure, the expression "transmitting a physical channel" may be interpreted as being equivalent to the expression "transmitting data or signals via a physical channel."

[0020] In addition, in this disclosure, expressions such as "more than" or "less than" are used to determine whether a particular condition is satisfied or fulfilled, but this is merely a description to express one example and does not exclude descriptions such as "more than" or "less than." A condition described as "more than" can be replaced with "more than," a condition described as "less than," and a condition described as "more than and less than" can be replaced with "more than and less than."

[0021] In addition, the present disclosure describes various embodiments using terms used in some communication standards (e.g., 3GPP (3rd Generation Partnership Project), xRAN (extensible radio access network), O-RAN (open-radio access network)), but this is merely an example for the purpose of explanation. Various embodiments of the present disclosure may be easily modified and applied to other communication systems.

[0022] FIG 1 illustrates a wireless communication system according to various embodiments of the present disclosure. FIG 1 illustrates a base station 110, a terminal 120, and a terminal 130 as some of the nodes that use wireless channels in the wireless communication system. Although FIG 1 illustrates only one base station, other base stations identical or similar to the base station 110 may also be included.

[0023] The base station 110 is a network infrastructure that provides wireless connectivity to the terminals 120 and 130. The base station 110 has coverage defined in a given geographical area based on the distance over which a signal can be transmitted. The base station 110 may be called an "access point (AP)", "eNodeB (eNB)", "5th generation node", "next generation nodeB (gNB)", "wireless point", "transmission / reception point (TRP)", or other terms having an equivalent technical meaning, in addition to a base station.

[0024] Each of the terminals 120 and 130 is a device used by a user and communicates with the base station 110 via a wireless channel. In some cases, at least one of the terminals 120 and 130 can be operated without the involvement of a user. That is, at least one of the terminals 120 and 130 is a device that performs machine type communication (MTC) and may not be carried by a user. Each of the terminals 120 and 130 may be referred to as a "user equipment (UE)", a "mobile station", a "subscriber station", a "remote terminal", a "wireless terminal", or a "user device" or other terms having an equivalent technical meaning, in addition to a terminal.

[0025] The base station 110, the terminal 120, and the terminal 130 can transmit and receive radio signals in the millimeter wave (mmWave) band (e.g., 28 GHz, 30 GHz, 38 GHz, and 60 GHz). In this case, the base station 110, the terminal 120, and the terminal 130 can perform beamforming to improve channel gain. Here, beamforming can include transmit beamforming and receive beamforming. That is, the base station 110, the terminal 120, and the terminal 130 can provide directivity to a transmit signal or a receive signal. To this end, the base station 110 and the terminals 120 and 130 can select serving beams 112, 113, 121, and 131 through a beam search or beam management procedure. After the serving beam 112, 113, 121, 131 is selected, subsequent communications may be conducted via resources that are in a quasi co-located (QCL) relationship with the resources that transmitted the serving beam 112, 113, 121, 131.

[0026] A first antenna port and a second antenna port may be said to be in a QCL relationship if the large-scale characteristics of the channel carrying symbols on the first antenna port can be inferred from the channel carrying symbols on the second antenna port. For example, the large-scale characteristics may include at least one of a delay spread, a Doppler spread, a Doppler shift, an average gain, an average delay, and a spatial receiver parameter.

[0027] In the present disclosure, a beam indicates a spatial flow of a signal in a wireless channel and is formed by one or more antennas (or antenna elements), and such a forming process can be referred to as beamforming. Beamforming can include analog beamforming and digital beamforming (e.g., precoding). Reference signals transmitted based on beamforming can 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, IEs such as a CSI-RS resource or an SRS-resource can be used as a configuration for each reference signal, and such a configuration can include information associated with the beam. The information associated with the beam may indicate whether the configuration (e.g., a CSI-RS resource) uses the same spatial domain filter as other configurations (e.g., other CSI-RS resources in the same CSI-RS resource set) or a different spatial domain filter, or which reference signal it is quasi-co-located with, and if so, what type (e.g., QCL type A, B, C, D).

[0028] When the base station stores a beam profile during the RU initialization process, it may store a common beam vector and each precoding vector in the order of each layer. Treating each of all terminals (i.e., users) as one layer and applying a weight vector (precoder) common to each terminal may be understood as forming a common beam applied to all terminals. Also, applying a specific precoder for multi-layers to each terminal may be understood as single-user beamforming for each terminal. Meanwhile, even if a precoder is applied to a terminal, signals transmitted to some terminals may be spatially distinguished from signals transmitted to other terminals. In this case, application of the corresponding precoder may be understood as multi-user beamforming.

[0029] In the past, in communication systems where the cell radius of base stations was relatively large, each base station was installed to include the functions of a digital processing unit (or DU (digital unit)) and an RF (radio frequency) processing unit (or RU (radio unit)). th In the 1990s (1991-1992) and / or later communication systems, high frequency bands have been used, and as the cell radius of base stations has become smaller, the number of base stations to cover a specific area has increased, and the burden of installation costs on operators to install the increased number of base stations has increased. In order to minimize the installation costs 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 distributed geographically to cover a specific area. Hereinafter, a base station arrangement structure and an extension example according to various embodiments of the present disclosure will be described with reference to FIG. 1B.

[0030] 1B shows an example of a fronthaul structure based on functional separation of a base station according to various embodiments of the present disclosure. Unlike a backhaul between a base station and a core network, a fronthaul refers to an entity between a wireless LAN and a base station.

[0031] Referring to FIG. 1B, the base station 110 may include a DU 160 and an RU 180. A fronthaul 170 between the DU 160 and the RU 180 may include a x For operation of the fronthaul 170, an interface such as enhanced common public radio interface (eCPRI) or radio over ethernet (ROE) may be used.

[0032] As communication technology develops, mobile data traffic increases, which in turn significantly increases the bandwidth requirements for the fronthaul between digital and wireless units. In a deployment such as C-RAN (centralized / cloud radio access network), the DU performs functions related to PDCP (packet data convergence protocol), RLC (radio link control), MAC (media access control), and PHY (physical), while the RU may be implemented to perform more functions related to the PHY layer in addition to radio frequency (RF) functions.

[0033] The DU 160 may be responsible for higher layer functions of a wireless network. For example, the DU 160 may perform a MAC layer function and a part of a PHY layer. Here, the part of the PHY layer refers to a function of the PHY layer that is performed at a higher step, 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 160 complies with the O-RAN standard, it may be referred to as an "O-DU (O-RAN DU)". The DU 160 may be expressed as a first network entity for a base station (e.g., gNB) in the embodiments of the present disclosure as necessary.

[0034] The RU 180 may be responsible for lower layer functions of a wireless network. For example, the RU 180 may perform a part of the PHY layer and an RF function. Here, the part of the PHY layer refers to a function of the PHY layer that is performed at a step relatively lower than the DU 160, and may include, for example, IFFT / FFT transformation, CP insertion / removal, and digital beamforming. An example of such a specific functional separation is described in detail in FIG. 4. The RU 180 may be referred to as an "access unit (AU)", "access point (AP)", "transmission / reception point (TRP)", "remote radio head (RRH)", "radio unit (RU)", or other terms having an equivalent technical meaning. According to an embodiment, if the RU 180 complies with the O-RAN standard, it may be referred to as an "O-RU (O-RAN RU)". The RU 180 may be expressed as a second network entity for a base station (e.g., gNB) in the embodiments of the present disclosure, as necessary.

[0035] Although FIG. 1B illustrates the base station including a DU and an RU, various embodiments of the present disclosure are not limited thereto. In some embodiments, the base station may be implemented in a distributed deployment with a centralized unit (CU) configured to perform functions of upper layers (e.g., packet data convergence protocol (PDCP), RRC) of an access network and a distributed unit (DU) configured to perform functions of lower layers. In this case, the distributed unit (DU) may include a digital unit (DU) and a radio unit (RU) in FIG. 1B. Between a core (e.g., 5G core (5GC) or next generation core (NGC)) network and a radio network (RAN), the base station may be implemented in a structure in which a CU, a DU, and a RU are arranged in this order. The interface between the CU and the distributed unit (DU) may be referred to as an F1 interface.

[0036] A centralized unit (CU) is connected to one or more DUs and can handle functions of a higher layer than the DU. For example, the CU can handle functions of the radio resource control (RRC) and packet data convergence protocol (PDCP) layers, and the DU and RU can handle functions of lower layers. The DU can perform radio link control (RLC), media access control (MAC), and some functions of the physical layer (high PHY), and the RU can handle the remaining functions of the PHY layer (low PHY). In addition, as an example, a digital unit (DU) can be included in a distributed unit (DU) depending on the implementation of a distributed arrangement of a base station. Hereinafter, unless otherwise defined, the operation of a digital unit (DU) and an RU will be described, but various embodiments of the present disclosure can be applied to either a base station arrangement including a CU or an arrangement in which a DU is directly connected to a core network without a CU (i.e., a CU and a DU are integrated and implemented as one entity). 2 shows a configuration of a DU in a wireless communication system according to various embodiments of the present disclosure. The configuration illustrated in FIG. 2 is a part of a base station, and may be understood as the configuration of the DU 160 in FIG. 1B. Terms such as "module" and "device" used below refer to a unit that processes at least one function or operation, which may be implemented in hardware or software, or a combination of hardware and software.

[0037] Referring to FIG. 2, the DU 160 includes a communication unit 210, a storage unit 220, and a control unit 230. The communication unit 210 can perform functions for transmitting and receiving signals in a wired communication environment. The communication unit 210 can include a wired interface for controlling a direct connection between devices via a transmission medium (e.g., copper wire, optical fiber). For example, the communication unit 210 can transmit an electrical signal to another device via a copper wire, or convert between an electrical signal and an optical signal. The communication unit 210 can be connected to a radio unit (RU). The communication unit 210 can be connected to a core network or a CU in a distributed configuration.

[0038] The communication unit 210 may also perform a function for transmitting and receiving signals in a wireless communication environment. For example, the communication unit 210 may perform a conversion function between a baseband signal and a bit string according to a physical layer standard of a system. For example, when transmitting data, the communication unit 210 generates complex symbols by encoding and modulating a transmission bit string. Also, when receiving data, the communication unit 210 recovers a received bit string by demodulating and decoding a baseband signal. Also, the communication unit 210 may include multiple transmission and reception paths. Also, according to an embodiment, the communication unit 210 may be connected to a core network or to another node (e.g., an integrated access backhaul (IAB)).

[0039] The communication unit 210 can transmit and receive signals. To this end, the communication unit 210 can include at least one transceiver. For example, the communication unit 210 can transmit a synchronization signal, a reference signal, system information, a message, a control message, a stream, control information, or data. In addition, the communication unit 210 can perform beamforming.

[0040] The communication unit 210 transmits and receives signals as described above. Therefore, all or part of the communication unit 210 can be referred to as a "transmitter," a "receiver," or a "transmitter / receiver." In the following description, transmission and reception via a wireless channel are used to include the above-mentioned processing performed by the communication unit 210.

[0041] Although not shown in FIG 2, the communication unit 210 may further include a backhaul communication unit for connection to a core network or other base stations. The backhaul communication unit provides an interface for communication with other nodes in the network. That is, the backhaul communication unit converts a bit string transmitted from the base station to other nodes, such as other access nodes, other base stations, upper nodes, and core networks, into a physical signal, and converts a physical signal received from other nodes into a bit string.

[0042] The storage unit 220 stores data such as basic programs, application programs, and setting information for the operation of the DU 160. The storage unit 220 may include a memory. The storage unit 220 may be configured as a volatile memory, a non-volatile memory, or a combination of a volatile memory and a non-volatile memory. The storage unit 220 provides the stored data in response to a request from the control unit 230. According to an embodiment, the storage unit 220 may store scheduling information (e.g., beam information, antenna port information) and flow information (e.g., eAxC) for each stream.

[0043] The control unit 230 controls the overall operation of the DU 160. For example, the control unit 230 transmits and receives signals via the communication unit 210 (or via the backhaul communication unit). The control unit 230 also records and reads data in the memory unit 220. The control unit 230 can perform the function of a protocol stack required by a communication standard. To this end, the control unit 230 can include at least one processor. In some embodiments, the control unit 230 can include a control message generator including resource allocation information for multi-layer scheduling and a flow identifier for transmitting the corresponding control message. The control message generator and the flow identifier can be an instruction set or code stored in the memory unit 230, and can be an instruction / code that at least temporarily resides in the control unit 230 or a memory space that stores the instruction / code, or can be part of a circuit that constitutes the control unit 230. According to various embodiments, the control unit 230 can control the DU 160 to perform operations according to various embodiments described below.

[0044] The configuration of the DU 160 shown in Fig. 2 is merely an example, and examples of the DU performing various embodiments of the present disclosure are not limited to the configuration shown in Fig. 2. That is, according to various embodiments, some configurations may be added, deleted, or changed.

[0045] Fig. 3 shows a configuration of an RU in a wireless communication system according to various embodiments of the present disclosure. The configuration illustrated in Fig. 3 is a part of a base station, and may be understood as the configuration of RU 180 in Fig. 1B. Terms such as "unit" and "device" used below refer to a unit that processes at least one function or operation, and may be implemented in hardware or software, or a combination of hardware and software.

[0046] Referring to FIG. 3, the RU 180 includes a communication unit 310 , a storage unit 320 , and a control unit 330 . The communication unit 310 performs a function of transmitting and receiving signals through a wireless channel. For example, the communication unit 310 up-converts a baseband signal to an RF band signal and transmits the signal through an antenna, and down-converts an RF band signal received through the antenna to a baseband signal. For example, the communication unit 310 may include a transmission filter, a reception filter, an amplifier, a mixer, an oscillator, a DAC, an ADC, etc.

[0047] Also, the communication unit 310 may include a number of transmission and reception paths. Furthermore, the communication unit 310 may include an antenna unit. The communication unit 310 may include at least one antenna array including a number of antenna elements. In terms of hardware, the communication unit 310 may be configured with a digital circuit and an analog circuit (e.g., RFIC (radio frequency integrated circuit)). Here, the digital circuit and the analog circuit may be implemented as one package. Also, the communication unit 310 may include a number of RF chains. The communication unit 310 may perform beamforming. The communication unit 310 may apply a beamforming weight to a signal to be transmitted or received in order to give the signal directivity according to the setting of the control unit 330. According to an embodiment, the communication unit 310 may include an RF (radio frequency) block (or RF unit).

[0048] In addition, the communication unit 310 can transmit and receive signals. To this end, the communication unit 310 can include at least one transceiver. The communication unit 310 can transmit downlink signals. The downlink signals can include a synchronization signal (SS), a reference signal (RS) (e.g., CRS (cell-specific reference signal), DM (demodulation)-RS), system information (e.g., MIB, SIB, RMSI (remaining system information), OSI (other system information)), a configuration message, control information, downlink data, etc. In addition, the communication unit 310 can receive uplink signals. 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), etc.

[0049] The communication unit 310 transmits and receives signals as described above. Therefore, all or part of the communication unit 310 can be referred to as a "transmitter," a "receiver," or a "transmitter / receiver." In the following description, transmission and reception performed via a wireless channel are used to include the above-mentioned processing performed by the communication unit 310.

[0050] The storage unit 320 stores data such as basic programs, application programs, and setting information for the operation of the RU 180. The storage unit 320 may be configured as a volatile memory, a non-volatile memory, or a combination of a volatile memory and a non-volatile memory. The storage unit 320 provides the stored data in response to a request from the control unit 330.

[0051] The controller 330 controls the overall operation of the RU 180. For example, the controller 330 transmits and receives signals via the communication unit 310. The controller 330 also records and reads data in the memory unit 320. The controller 330 can perform the functions of a protocol stack required by a communication standard. To this end, the controller 330 can include at least one processor. The controller 330 can include various modules for performing communication. According to various embodiments, the controller 330 can control the terminal to perform operations according to various embodiments described below.

[0052] FIG. 4 illustrates an example of function split in a wireless communication system according to various embodiments of the present disclosure. As wireless communication technology develops (e.g., 5G (5 th With the introduction of the 5G (5G generation) communication system (or new radio (NR) communication system), the number of RUs required to be installed has increased as the frequency bands used have increased and the cell radius of base stations has become very small. In addition, the amount of data transmitted in the 5G communication system has increased by more than 10 times, and the transmission capacity of the wired network transmitted in the fronthaul has increased significantly. Due to these factors, 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 reduce the installation cost of the wired network, a technology has been proposed to transfer some of the functions of the DU modem to the RU to reduce the transmission capacity of the fronthaul, and this technology can be called "function split."

[0053] In order to reduce the burden on the DU, a method is being considered to expand the role of the RU, which is responsible for only RF functions, to some of the physical layer functions. In this case, the higher the layer function the RU performs, the higher the RU's processing volume increases, the greater the transmission bandwidth in the fronthaul, and the lower the constraints on latency requirements due to response processing. On the other hand, the higher the layer function the RU performs, the less the virtualization gain is, and the larger / weight / cost of the RU increases. It is necessary to implement optimal functional separation by considering the trade-off between the above advantages and disadvantages.

[0054] Referring to FIG. 4, functional separation in the physical layer below the MAC layer is illustrated. In the case of a downlink (DL) transmitting a signal to a terminal via a wireless network, a base station may sequentially perform channel encoding / scrambling, modulation, layer mapping, antenna mapping, RE mapping, digital beamforming (e.g., precoding), IFFT transformation / CP insertion, and RF conversion. In the case of an uplink (UL) receiving a signal from a terminal via a wireless network, a base station may sequentially perform RF conversion, FFT transformation / CP removal, digital beamforming (pre-combining), RE demapping, channel estimation, layer demapping, demodulation, and decoding / descrambling. The separation of the uplink function and the downlink function may be defined into various types according to the needs of vendors, standard discussions, etc., depending on the above-mentioned trade-off.

[0055] The first function separation 405 may be a separation of an RF function and a PHY function. The first function separation is such that the PHY function is not actually implemented in the RU, and may be referred to as Option 8, for example. The second function separation 410 is such that the RU performs IFFT conversion / CP insertion in DL and FFT conversion / CP removal in UL of the PHY function, and the DU performs the remaining PHY functions. For example, the second function separation 410 may be referred to as Option 7-1. The third function separation 420a is such that the RU performs IFFT conversion / CP insertion in DL of the PHY function, and FFT conversion / CP removal and digital beamforming in UL, and the DU performs the remaining PHY functions. For example, the third function separation 420a may be referred to as Option 7-2x Category A. The fourth function separation 420b is such that the RU performs up to digital beamforming in both DL and UL, and the DU performs higher PHY functions after digital beamforming. For example, the fourth function separation 420b may be referred to as Option 7-2x Category B. In the fifth function separation 425, the RU performs up to RE mapping (or RE demapping) in both DL and UL, and the DU performs higher PHY functions after RE mapping (or RE demapping). As an example, the fifth function separation 425 may be referred to as Option 7-2. In the sixth function separation 430, the RU performs up to modulation (or demodulation) in both DL and UL, and the DU performs higher PHY functions after modulation (or demodulation). As an example, the sixth function separation 430 may be referred to as Option 7-3. In the seventh function separation 440, the RU performs up to encoding / scrambling (or decoding / descrambling) in both DL and UL, and the DU performs higher PHY functions after modulation (or demodulation). As an example, the seventh function separation 440 may be referred to as Option 6.

[0056] According to an embodiment, when large-capacity signal processing is expected, such as in the FR1 MMU, functional separation at a relatively high layer (e.g., fourth functional separation 420b) may be required to reduce fronthaul capacity. In addition, functional separation at an excessively high layer (e.g., sixth functional separation 430) may complicate the control interface and include many PHY processing blocks in the RU, which may cause a burden on the implementation of the RU, so appropriate functional separation may be required depending on the arrangement and implementation method of the DU and RU.

[0057] According to an embodiment, when the RU is unable to process precoding of data received from the DU (i.e., when the RU has limited precoding capability), the third function separation 420a or a lower function separation (e.g., the second function separation 410) may be applied. Conversely, when the RU is capable of processing precoding of data received from the DU, the fourth function separation 420b or a higher function separation (e.g., the sixth function separation 430) may be applied. Hereinafter, various embodiments in the present disclosure will be described based on the third function separation 420a or the fourth function separation 420b unless otherwise limited, but the configuration of embodiments based on other function separations is not excluded. For example, in the case of the sixth function separation 430 (Option 7-3), the embodiments described below may also be applied.

[0058] FIG. 5 illustrates an example of beams that can be formed by a RU of a base station in a wireless communication system according to various embodiments of the present disclosure. The RU includes an antenna array 510 including a plurality of antenna elements. Using the antenna array 510, the RU can perform beamforming. For example, the RU can form a first beam 520a, a second beam 520b, a third beam 520c, a fourth beam 520d, and a fifth beam 520e having different directions. Depending on the hardware capabilities of the RU, two or more of the first beam 520a, the second beam 520b, the third beam 520c, the fourth beam 520d, and the fifth beam 520e can be formed simultaneously. The number of beams that can be formed simultaneously can be related to the number of RF chains of the RU.

[0059] For example, when three beams such as a first beam 520a, a second beam 520b, and a third beam 520c can be formed simultaneously, the beams can be applied by resource as shown in FIG. 6 below. FIG. 6 illustrates an example of a resource element (RE) mask in a wireless communication system according to various embodiments of the present disclosure. FIG. 6 illustrates a case where three beams are used in a resource region including 14 symbols and 12 REs. The resource region as shown in FIG. 6 can be referred to as a "section," "resource block (RB)," or other term having an equivalent technical meaning.

[0060] The RU maps the beam to the resource according to the control of the DU. In other words, the RU transmits the signal to be transmitted through the resource according to the control of the DU via the beam. At this time, one section may be mapped to one beam. However, beams applied to resources belonging to one RB or one section may be different from each other. For example, as shown in FIG. 6, a first beam may be mapped to REs 600, 601, 602, 603, 604, 605, 607, 608, 610 having indexes 0 to 5, 7, 8, 10, a second beam may be mapped to REs 606, 609 having indexes 6, 9, and a third beam may be mapped to RE 611 having index 11. In other words, the signals mapped to the 2nd, 5th, and 8th subcarriers may be beamformed to be transmitted through the first beam, the signals mapped to the 6th and 9th subcarriers may be beamformed to be transmitted through the second beam, and the signals mapped to the 11th subcarrier may be beamformed to be transmitted through the third beam. In this case, one section is mapped to one beam, and masking techniques may be used to express that the beam is mapped to some resources (e.g., REs or carriers) within one section.

[0061] For example, a DU can provide a mask value of "111111011010" for the first beam, indicating that the first beam is mapped to a section as shown in Figure 6. Similarly, the mask value for the second beam can be expressed as "000000100100", and the mask value for the third beam can be expressed as "000000000001". Here, the mask for the first beam can be expressed as "reMask_A", the mask for the second beam as "reMask_B", and the mask for the third beam as "reMask_C". The XOR (exclusive or) operation result of the three mask values ​​arranged in order is "111111111111".

[0062] Using the above mask value, the RU can determine which RE or subcarrier among the REs in the section the first beam, second beam, or third beam is applied to based on the bit pattern of the mask value. The RU allocates memory space for storing at least one mask value received from the DU, and stores at least one mask value in the allocated memory space. Thereafter, when transmitting a signal through the corresponding section, the RU can perform beamforming for each RE using the mask value and beam information. At this time, the mask value may be stored as a pair with section information (e.g., section ID). For example, when three masks are received as shown in FIG. 6, memory space as shown in FIG. 7 may be required.

[0063] 7 shows an example of memory space for storing mask values ​​in a wireless communication system according to various embodiments of the present disclosure. Referring to FIG. 7, a first space 701 is allocated for storing section ID values ​​and mask values ​​for a first beam, a second space 702 is allocated for storing section ID values ​​and mask values ​​for a second beam, and a third space 703 is allocated for storing section ID values ​​and mask values ​​for a third beam. That is, if three mask values ​​are received, a memory space capable of storing at least three mask values ​​and three section ID values ​​is required.

[0064] Meanwhile, the DU controls the RU using control signaling. The control message received from the DU is stored in the RU and then decoded. At this time, the stored C-plane message may be stored in a predetermined time unit (e.g., one slot or 14 symbols). If a quantity of messages that exceeds the memory capacity used by the RU is received within a predetermined time unit, some of the messages may be lost and decoding may fail. Here, the control message transmitted from the DU may be a C (control)-plane message.

[0065] In order to prevent a situation in which a message is transmitted in an amount that exceeds the available memory capacity, the RU can report the available memory capacity to the DU, so that the DU can transmit a control message taking into account the available memory capacity of the RU. Here, the message transmitted from the RU may be an M(management)-plane message.

[0066] If there is no operation to inform the RU of the available memory capacity, the DU can send a control message without considering the available memory capacity of the RU. In this case, the RU needs to allocate memory space according to the maximum size of the message that the DU can send. For example, in the case of an RE mask, since one section contains 12 REs, it is possible to expect to receive a control message containing up to 12 mask values. Securing memory space capable of storing up to 12 mask values ​​in preparation for the maximum 12 mask values ​​may increase the implementation cost of the RU.

[0067] Furthermore, reserving memory space capable of storing 12 mask values ​​may result in unnecessary waste of memory space. Currently, the combinations that can be assigned within one section of a downlink channel defined in the 5G (5th generation) NR (new radio) standard may not be infinite. Depending on the specific implementation, the following combinations [Table 1] may be considered. [Table 1]

[0068] When the combinations in Table 1 above are considered, the maximum number of channels that can be transmitted in one section is 3. In this case, since more than three beams are not used in one section, reserving memory space capable of storing four or more mask values ​​may result in a waste of memory space.

[0069] Also, in the absence of an action to inform the RU of the available memory capacity, the DU may transmit a message whose size exceeds the available memory capacity of the RU. In this case, at least a part of the message may not be stored and decoding may fail. For example, if the RU reserves only memory space that can store two mask values, but the DU transmits a control message containing three mask values, decoding of the control message may fail.

[0070] 8 is a flow chart 800 illustrating the operation of an RU in a wireless communication system according to various embodiments of the present disclosure. FIG. 8 illustrates a method of operation of an RU 180 of a base station 110.

[0071] 8, in operation 801, the RU transmits a message including a value indicating the maximum RE mask number. Here, the maximum RE mask number can be understood to be the number of pairs of mask value and section ID value that can be stored in the RU. That is, the RU transmits to the DU a value corresponding to the amount of memory space that can be allocated for storing RE mask values ​​in the memory.

[0072] In operation 803, the RU receives a message for controlling the RU. The RU can store the received message in a memory space. For example, the message can include scheduling information associated with the operation of the RU. Specifically, the message can include at least one RE mask value. The RU can obtain the information included in the message by decoding the message stored in the memory space.

[0073] 9 is a flow chart 900 illustrating the operation of a digital unit (DU) in a wireless communication system according to various embodiments of the present disclosure. FIG. 9 illustrates an operation method of the DU 160 of the base station 110.

[0074] 9, in operation 901, the DU receives a message including a value indicating a maximum RE mask number from the RU. Here, the maximum RE mask number can be understood to be the number of pairs of mask value and section ID value that can be stored in the RU. That is, the DU receives a value from the RU corresponding to the amount of memory space that can be allocated for storing RE mask values ​​in the memory.

[0075] In operation 903, the DU sends a message for controlling the RU. For example, the message may include scheduling information associated with the operation of the RU. The DU may limit the size of the message based on the value received in operation 901. To this end, in the scheduling operation, the DU may perform scheduling such that more beams than the number of RE masks corresponding to the value received in operation 901 are not used in one section.

[0076] 10 illustrates a signal exchange between a DU and a RU in a wireless communication system according to various embodiments of the present disclosure. FIG 10 illustrates a specific example of the operation of the RU 180 according to FIG 8 and the operation of the DU 160 according to FIG 9.

[0077] Referring to FIG. 10, the RU 180 transmits an M-plane message 1002 to the DU 160. The M-plane message 1002 includes information on the status or resources of the RU 180. For example, the M-plane message 1002 may include at least one of "max-sections-per-symbol" indicating the maximum number of sections per symbol, "max-sections-per-slot" indicating the maximum number of sections per slot, and "max-remask-per-section" indicating the maximum number of RE masks per section. The M-plane message 1002 may be transmitted during a procedure for the RU 180 and the DU 160 to set up an initial connection or after completing a procedure for setting up a connection. Then, the DU 160 transmits a C-plane message 1004 to control the operation of the RU 180. For example, the C-plane message 1004 may include scheduling information (e.g., RE mask) for the operation of the RU 180.

[0078] In the procedure illustrated in FIG. 10, the M-plane message 1002 may further include information such as the following Table 2. [Table 2]

[0079] In the procedure illustrated in FIG. 10, the C-plane message 1004 may be configured as shown in Table 3, Table 4, Table 5, or Table 6 below. [Table 3] TIFF0007652506000004.tif55170

[0080] In Table 3, whether or not section extension is performed is determined by the "ef" parameter value in octet 23. If "ef=0", section extension is not performed, and if "ef=1", section extension is performed, i.e., "reMask" is added. In other words, section extension can be performed to add "reMask". At this time, when generating and transmitting a C-plane message, the DU performs section extension taking into account the available memory capacity of the RU. For example, if section extension is never performed, octet 23 contains "ef=0", and at the same time, octets 21 and 22 contain "reMask=11111111111", which means that only one beam is used in the corresponding section.

[0081] The message structure of Table 3 can be modified as shown in Table 4 or Table 5 below depending on the section type. Table 4 below shows a message for section type 0, Table 5 below shows a message for section type 1, and Table 6 below shows a message for section type 3. [Table 4] TIFF0007652506000006.tif75170 [Table 5] TIFF0007652506000008.tif40170 [Table 6] TIFF0007652506000010.tif87165

[0082] As in the various embodiments described above, the RU provides information on the maximum number of RE masks that can be stored in the DU, so that a control message can be generated and transmitted without exceeding the available memory capacity of the RU. That is, the information on the maximum number of RE masks can be understood as a value for informing the available memory capacity.

[0083] Therefore, according to other embodiments, the maximum number of RE masks may be replaced by information that explicitly or implicitly indicates the available memory capacity, where the available memory capacity signaled may be the total available memory capacity for storing control messages or the available memory capacity that can be allocated for a specific information item (e.g., RE mask value), where the specific information item may be information for the RE mask or other information.

[0084] Also, according to another embodiment, the value indicating the maximum number of RE masks may be replaced with a value associated with the number of other parameters other than the RE masks. Since the number of RE masks may be repeatedly included in the control message, the maximum number of RE masks affects the memory capacity. Therefore, the number value of other parameters that may be repeatedly included in the control message may be reported in parallel with or instead of the RE mask. However, even for non-repetitive parameters, information for informing whether or not memory space for storing the parameter can be allocated may be reported. That is, a value indicating the presence or absence, rather than the number, may be used.

[0085] The methods according to the embodiments described in the claims or specification of the present disclosure may be implemented in the form of hardware, software, or a combination of hardware and software.

[0086] In the case of a software implementation, a computer-readable storage medium may be provided that stores one or more programs (software modules). The one or more programs stored in the computer-readable storage medium are configured for execution by one or more processors in an electronic device. The one or more programs include instructions that cause the electronic device to execute a method according to the embodiments described in the claims or specification of the present disclosure.

[0087] Such programs (software modules, software) may be stored in random access memory, non-volatile memory including flash memory, read only memory (ROM), electrically erasable programmable read only memory (EEPROM), magnetic disc storage device, compact disc-ROM (CD-ROM), digital versatile discs (DVDs) or other forms of optical storage, magnetic cassette, or in a memory configured as a combination of some or all of them. Also, each of the constituent memories may include multiple pieces.

[0088] The program may also be stored in an attachable storage device that can be accessed through a communication network such as the Internet, an Intranet, a local area network (LAN), a wide area network (WAN), or a storage area network (SAN), or a combination thereof. Such a storage device can be accessed by an apparatus that performs an embodiment of the present disclosure through an external port. Also, a separate storage device on the communication network can be accessed by an apparatus that performs an embodiment of the present disclosure.

[0089] In the specific embodiments of the present disclosure described above, the components included in the disclosure are expressed in the singular or plural form according to the specific embodiments presented. However, the expressions singular or plural are selected to suit the circumstances presented for the convenience of explanation, and the present disclosure is not limited to the singular or plural components, and the components expressed in the plural form may be composed in the singular form, and the components expressed in the singular form may be composed in the plural form.

[0090] Meanwhile, although the detailed description of the present disclosure has been given with respect to specific embodiments, it is of course possible to make various modifications without departing from the scope of the present disclosure. Therefore, the scope of the present disclosure should not be limited to the described embodiments, but should be determined by not only the claims set forth below, but also equivalents thereto. [Explanation of symbols]

[0091] 110 base station 120 terminals 130 terminals 160 DU 170 Front Hall 180RU 210 Communications Department 220 Storage section 230 Control Unit 310 Communications Department 320 Storage section 330 Control Unit

Claims

1. A method performed by a radio unit (RU) in a wireless communication system, comprising: transmitting a first message including a value indicating a maximum number of a plurality of resource element (RE) masks for the section to a digital unit (DU); receiving, from the DU, a second message generated based on the value; The maximum number of the plurality of RE masks is the maximum number of pairs of an RE mask and a section ID (identifier), The RE mask indicates at least one RE associated with one beam within the section.

2. The method comprises: The method of claim 1 , further comprising the step of: storing at least one value of the RE mask included in the second message by time unit.

3. The method of claim 1 , wherein the second message is based on an available memory capacity of the RU.

4. The first message further includes at least one of a value indicating a maximum number of the sections per symbol or a value indicating a maximum number of the sections per slot; The method of claim 1 , wherein the second message includes a value indicating a number of RE masks that is less than or equal to a maximum number of the plurality of RE masks.

5. The method of claim 1 , wherein the first message is transferred during an initial connection procedure of the RU and the DU.

6. The first message includes a management-plane message; The second message includes a control-plane message; The second message further includes section extension information including information indicating the RE mask; The method of claim 1 , wherein the section extension information is associated with one of section type 0, section type 1, or section type 3.

7. A method performed by a digital unit (DU) in a wireless communication system, comprising: receiving a first message from a radio unit (RU), the first message including a value indicating a maximum number of resource element (RE) masks for the section; transmitting to the RU a second message generated based on the value; The maximum number of the plurality of RE masks is the maximum number of pairs of an RE mask and a section ID (identifier), The RE mask indicates at least one RE associated with one beam within the section.

8. The second message is The method of claim 7, based on the available memory capacity of the RU.

9. The first message further includes at least one of a value indicating a maximum number of the sections per symbol or a value indicating a maximum number of the sections per slot; The method of claim 7 , wherein the second message includes a value indicating a number of RE masks that is less than or equal to a maximum number of the plurality of RE masks.

10. The method of claim 7 , wherein the first message is received during an initial connection procedure of the RU and the DU.

11. The first message includes a management-plane message; The second message includes a control-plane message; The second message further includes section extension information including information indicating the RE mask; The method of claim 7 , wherein the section extension information relates to one of section type 0, section type 1, or section type 3.

12. The method according to claim 1, The method of claim 7 , further comprising the step of: storing at least one value of the RE mask included in the second message on a time basis.

13. A radio unit (RU) in a wireless communication system, Transceiver and A controller coupled to the transceiver, The RU, wherein the controller is configured to implement any one of claims 1 to 6.

14. A distributed unit (DU) in a wireless communication system, Transceiver and A controller coupled to the transceiver, The DU, wherein the controller is configured to implement any one of claims 7 to 12.

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