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

Abstract

The present disclosure relates to a quasi-fifth generation (5G) or 5G communication system that will be provided to support higher data rates than fourth generation (4G) communication systems such as long term evolution (LTE). A method for operating a radio unit (RU) of a base station is provided. The method includes sending a first message including a value indicating a maximum number of masks for a 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 within the resource region to which the same beam is applied.

Description

Technical Field

[0001] The present disclosure relates to a wireless communication system, 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 Art

[0002] To meet the growing demand for wireless data traffic following the commercialization of the fourth-generation (4G) communication system, efforts are underway to develop advanced fifth-generation (5G) or pre-5G communication systems. These systems are referred to as "beyond 4G" network communication systems or post-Long Term Evolution (LTE) systems.

[0003] To achieve high data rates, 5G communication systems are being considered for implementation in extremely high-frequency millimeter wave (mmWave) bands (e.g., 28 GHz or 60 GHz bands). To mitigate propagation path loss and extend propagation distances in these extremely high frequency bands, 5G communication systems are being considered using beamforming, massive multiple-input multiple-output (MIMO), full-dimensional (FD) MIMO, array antennas, analog beamforming, and massive antenna technologies.

[0004] In addition, for network enhancement of the system, 5G communication systems are developing technologies such as evolved small cells, advanced small cells, cloud radio access networks (RAN), ultra-dense networks, device-to-device (D2D) communication, wireless backhaul, mobile networks, collaborative communications, coordinated multi-point (CoMP), and receive interference cancellation.

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

[0006] As transmission capacity in wireless communication systems increases, functional splitting (FSP) is being applied to 5G systems to functionally separate base stations. Through functional splitting, base stations are divided into a digital unit (DU) and a radio unit (RU), with the RU operating under the control of the DU.

[0007] The above information is provided as background information only to assist with an understanding of the present disclosure. No determination has been made, and no assertion is made, as to whether any of the above might be applicable as prior art to the present disclosure. Summary of the Invention

[0008] Solution to the problem

[0009] Aspects of the present disclosure are to address at least the above-mentioned problems and / or disadvantages and to provide at least the advantages described below. Therefore, one aspect of the present disclosure is to provide an apparatus and method for efficiently controlling a radio unit (RU) of a base station in a wireless communication system.

[0010] Another aspect of the present disclosure is to provide an apparatus and method for effectively managing resources of RUs of a base station in a wireless communication system.

[0011] Another aspect of the present disclosure is to provide an apparatus and method for preventing memory waste of a RU of a base station in a wireless communication system.

[0012] Additional aspects will be set forth in part in the description which follows and, in part, will be apparent from the description, or may be learned by practice of the presented embodiments.

[0013] According to one aspect of the present disclosure, a method for operating a radio unit (RU) of a base station in a wireless communication system is provided. The method includes sending a first message including a value indicating a maximum number of masks for a 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 within the resource region to which the same beam is applied.

[0014] According to another aspect of the present disclosure, a method for operating a digital unit (DU) of a base station in a wireless communication system is provided. The method includes: receiving a first message from a radio unit (RU) including a value indicating a maximum number of masks for a resource region; and transmitting a second message generated based on the value to the RU, wherein the mask may indicate resources within the resource region to which the same beam is applied.

[0015] According to another aspect of the present disclosure, a radio unit (RU) of a base station in a wireless communication system is provided. The RU includes a transceiver and at least one processor connected to the transceiver. The at least one processor can be configured to send a first message including a value indicating a maximum number of masks for a resource region to a digital unit (DU), and receive a second message generated based on the value from the DU, wherein the mask can indicate resources within the resource region to which the same beam is applied.

[0016] According to another aspect of the present disclosure, a digital unit (DU) of a base station in a wireless communication system is provided. The DU includes a transceiver and at least one processor connected to the transceiver. The at least one processor can be configured to receive a first message including a value indicating a maximum number of masks for a resource region from a radio unit (RU), and to send a second message generated based on the value to the RU, wherein the mask may indicate resources within the resource region to which the same beam is applied.

[0017] Apparatuses and methods according to various embodiments may prevent unnecessary waste of resources in a radio unit (RU) of a base station.

[0018] Other aspects, advantages, and salient features of the disclosure will become apparent to those skilled in the art from the following detailed description, which, taken in conjunction with the annexed drawings, discloses various embodiments of the disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The above and other aspects, features and advantages of certain embodiments of the present disclosure will become more apparent through the following description in conjunction with the accompanying drawings, in which:

[0020] Figure 1A A wireless communication system according to an embodiment of the present disclosure is shown;

[0021] Figure 1B An example of a fronthaul structure of a base station with functional division according to an embodiment of the present disclosure is shown;

[0022] Figure 2 shows a configuration of a digital unit (DU) in a wireless communication system according to an embodiment of the present disclosure;

[0023] Figure 3 shows a configuration of a radio unit (RU) in a wireless communication system according to an embodiment of the present disclosure;

[0024] Figure 4 An example of functional division in a wireless communication system according to an embodiment of the present disclosure is shown;

[0025] Figure 5 An example of a beam that can be formed in an RU of a base station in a wireless communication system according to an embodiment of the present disclosure is shown;

[0026] Figure 6 An example of a resource element (RE) mask in a wireless communication system according to an embodiment of the present disclosure is shown;

[0027] Figure 7 An example of a memory space for storing mask values in a wireless communication system according to an embodiment of the present disclosure is shown;

[0028] Figure 8 is a flowchart illustrating the operation of an RU in a wireless communication system according to an embodiment of the present disclosure;

[0029] Figure 9 is a flowchart illustrating an operation of a digital unit (DU) in a wireless communication system according to an embodiment of the present disclosure; and

[0030] Figure 10 Schematic diagram illustrating signal exchange between a DU and a RU in a wireless communication system according to an embodiment of the present disclosure.

[0031] The same reference numbers are used throughout the drawings to denote the same elements. DETAILED DESCRIPTION

[0032] The following description with reference to the accompanying drawings is provided to facilitate a comprehensive understanding of the various embodiments of the present disclosure as defined by the claims and their equivalents. The following description includes various specific details to assist understanding, but these details are to be regarded as exemplary only. Therefore, those skilled in the art will recognize that various changes and modifications may be made to the various embodiments described herein without departing from the scope and spirit of the present disclosure. In addition, descriptions of well-known functions and configurations may be omitted for clarity and brevity.

[0033] The terms and words used in the following description and claims are not limited to the bibliographical meanings, but are merely used by the inventor to enable a clear and consistent understanding of the disclosure. Therefore, it should be apparent to those skilled in the art that the following description of various embodiments of the present disclosure is provided for illustration purposes only and is not intended to limit the present disclosure as defined by the appended claims and their equivalents.

[0034] It should be understood that the singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to "a component surface" includes reference to one or more of such surfaces.

[0035] The following will describe various embodiments of the present disclosure based on a hardware approach. However, various embodiments of the present disclosure include technologies using both hardware and software, and therefore, the various embodiments of the present disclosure do not exclude the software aspect.

[0036] The present disclosure relates to an apparatus and method for managing resources of a radio unit (RU) of a base station including a digital unit (DU) and at least one radio unit (RU) in a wireless communication system. Specifically, the present disclosure describes a technique for managing memory resources of a RU of a base station in a wireless communication system.

[0037] Hereinafter, terms used herein relating to signals (e.g., message, information, preamble, signal, signaling, sequence, and stream), terms relating to resources (e.g., symbol, slot, subframe, radio frame, subcarrier, resource element (RE), resource block (RB), bandwidth part (BWP), and opportunity), terms relating to operating states (e.g., operation and procedure), terms relating to data (e.g., user stream, orthogonal (IQ) data, information, bit, symbol, and codeword), terms relating to channels, terms relating to control information (e.g., downlink control information (DCI), medium access control control element (MAC CE), and radio resource control (RRC) signaling), terms relating to network entities, terms relating to elements of devices, etc., are for convenience of description. Therefore, the present disclosure is not limited to the terms described later, and other terms with equivalent technical meanings may be used.

[0038] In the following description, the terms "physical channel" and "signal" may be used interchangeably with "data" or "control signal." For example, the term "physical downlink shared channel" (PDSCH) 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 "transmitting data or a signal through a physical channel."

[0039] In addition, in the present disclosure, although the expression "greater than" or "less than" has been used to determine whether a specific condition is satisfied or achieved, this does not exclude the expression "equal to or greater than" or "equal to or less than." Under the above conditions, the expression "equal to or greater than" can be replaced with "greater than," the expression "equal to or less than" can be replaced with "less than," and the expression "equal to or greater than and less than" can be replaced with "greater than and equal to or less than."

[0040] In addition, the present disclosure will use terms used in some communication standards (e.g., 3rd Generation Partnership Project (3GPP), Scalable Radio Access Network (xRAN), or Open Radio Access Network (O-RAN)) to describe various embodiments, but this is only an example for description. Various embodiments can be easily modified and applied to other communication systems.

[0041] Figure 1A A wireless communication system according to an embodiment of the present disclosure is shown.

[0042] refer to Figure 1A , shows a base station 110, a terminal 120, and a terminal 130 as some of the nodes using a radio channel in a wireless communication system. Figure 1A Only one base station is shown, but another base station that is the same as or similar to the base station 110 may additionally be included.

[0043] Base station 110 is a network infrastructure that provides wireless connectivity to terminals 120 and 130. Base station 110 has a coverage area, defined as a specific geographic area, based on the distance over which base station 110 can transmit signals. In addition to "base station," base station 110 may also be referred to as an "access point (AP)," "eNodeB (eNB)," "fifth generation (5G) node," "next generation NodeB (gNB)," "radio point," "transmit / receive point (TRP)," or other technically equivalent terms.

[0044] Each of the terminals 120 and 130 is a device used by a user and communicates with the base station 110 through a radio channel. In some cases, at least one of the terminals 120 and 130 can operate without user participation. 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. In addition to the term "terminal", each of the terminals 120 and 130 may be referred to as a "user equipment (UE)", "mobile station", "subscriber station", "remote terminal", "wireless terminal", "user device" or other terms with equivalent technical meanings.

[0045] The base station 110, the terminal 120, and the terminal 130 can transmit and receive wireless signals in the millimeter wave (mmWave) frequency band (e.g., 28 GHz, 30 GHz, 38 GHz, or 60 GHz). In this case, in order to improve the channel gain, the base station 110, the terminal 120, and the terminal 130 can perform beamforming. Beamforming can include transmit beamforming and receive beamforming. That is, the base station 110, the terminal 120, and the terminal 130 can give directionality to the transmitted or received signals. To this end, the base station 110 and the terminals 120 and 130 can select the service beams 112, 113, 121, and 131 through a beam search or management process. After selecting the service beams 112, 113, 121, and 131, subsequent communications can be performed through resources having a quasi-co-location (QCL) relationship with the resources to which the service beams 112, 113, 121, and 131 are transmitted.

[0046] If a large-scale characteristic of a channel carrying symbols on a first antenna port can be inferred from a channel carrying symbols on a second antenna port, it can be determined that a QCL relationship exists between the first antenna port and the second antenna port. For example, the large-scale characteristic may include at least one of delay spread, Doppler spread, Doppler shift, average gain, average delay, and spatial receiver parameters.

[0047] In the present disclosure, a beam refers to the spatial flow of a signal in a radio channel and can be formed by one or more antennas (or antenna elements), and the formation 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, an information element (IE) such as a CSI-RS resource or an SRS resource can be used as a configuration for each reference signal, and the configuration can include information associated with the beam. The information associated with the beam can indicate whether the corresponding configuration (e.g., CSI-RS resource) uses the same spatial domain filter as another configuration (e.g., another CSI-RS resource in 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 it is QCL), information about the QCL type (e.g., QCL type A, B, C, or D).

[0048] When storing the beam profile during the RU initialization process, the base station can store the common beam vector and the corresponding precoding vector in the order of layers. Applying a common weight vector (precoder) to each terminal when the corresponding terminal in all terminals (i.e., users) is regarded as one layer can be understood as forming a common beam applied to all terminals. In addition, applying a specific precoder for multiple layers to each terminal can be understood as single-user beamforming for each terminal. At the same time, even if the precoder is applied to the terminal, the signals sent to some terminals can be spatially distinguished from the signals sent to other terminals. In this case, the application of the precoder can be understood as multi-user beamforming.

[0049] Typically, in a communication system in which the cell radius of a base station is relatively large, each base station includes the functions of a digital processing unit (or digital unit (DU)) and a radio frequency (RF) processing unit (or radio unit (RU)). However, since high frequency bands are used and the cell radius of base stations is reduced in fourth generation (4G) communication systems and / or subsequent communication systems, the number of base stations covering a specific area increases, and the increase in the number of base stations increases the installation cost of operators. In order to minimize the installation cost of a base station, 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 through a wired network, and one or more RUs are deployed to be geographically distributed to cover a specific area. Hereinafter, reference will be made to Figure 1B Described are examples of deployment structures and extensions of base stations according to various embodiments.

[0050] Figure 1B An example of a fronthaul structure divided according to the functions of a base station according to an embodiment of the present disclosure is shown. Unlike the backhaul between the base station and the core network, the fronthaul refers to the link between entities, that is, the link between the wireless local area network (LAN) and the base station.

[0051] refer to Figure 1B , the base station 110 may include a DU 160 and a RU 180. The fronthaul 170 between the DU 160 and the RU 180 may be operated through an Fx interface. For example, interfaces such as an enhanced Common Public Radio Interface (eCPRI) and Radio over Ethernet (ROE) may be used for the fronthaul 170 operation.

[0052] Advances in communications technology have increased mobile data traffic, necessitating a significant increase in the bandwidth required for fronthaul between digital units and radio units. In deployments such as centralized / cloud radio access networks (C-RAN), the DU can be implemented to perform packet data convergence protocol (PDCP), radio link control (RLC), medium access control (MAC), and physical layer (PHY) functions, and the RU can be implemented to perform PHY layer functions in addition to radio frequency (RF) functions.

[0053] The DU 160 can perform the functions of the upper layers in the wireless network. For example, the DU 160 can perform the functions of the MAC layer and some functions of the PHY layer. Here, some functions of the PHY layer refer to functions performed at a higher level among the functions of the PHY layer, and may include, for example, channel coding (or channel decoding), scrambling (or descrambling), modulation (or demodulation), and layer mapping (or layer demapping). According to an embodiment, if it complies with the O-RAN standard, the DU 160 may be referred to as an "O-RAN DU (O-DU)". In an embodiment, the DU 160 may be replaced by the first network entity for a base station (e.g., a gNB) as needed.

[0054] The RU 180 may perform functions of lower layers in a wireless network. For example, the RU 180 may perform some functions of the PHY layer and RF functions. Here, some functions of the PHY layer refer to functions performed at a relatively lower level than the DU 160 among the functions of the PHY layer, and may include, for example, inverse fast Fourier transform (IFFT) / fast Fourier transform (FFT) conversion, cyclic prefix (CP) addition / removal, and digital beamforming. Figure 4A detailed example of functional division is described in detail. The RU 180 may be referred to as an "access unit (AU)", "access point (AP)", "transmission / reception point (TRP)", "remote radio head (RRH)", "radio radio unit (RU)", or other terms with equivalent technical meanings. According to an embodiment, if the RU 180 complies with the O-RAN standard, it may be referred to as an "O-RAN RU (O-RU)". In an embodiment, the DU 180 may be replaced by a second network entity for a base station (e.g., a gNB) as needed.

[0055] Although already Figure 1B , it is described that the base station includes a DU and a RU, but various embodiments are not limited thereto. In some embodiments, the base station can be implemented in a distributed deployment according to a centralized unit (CU) configured to perform functions of upper layers of the access network (e.g., Packet Data Convergence Protocol (PDCP) and RRC) and a distributed unit (DU) configured to perform functions of lower layers. In this case, the distributed unit (DU) may include Figure 1B The digital unit (DU) and radio unit (RU) shown. The base station can be implemented in a structure in which the CU, DU, and RU are sequentially arranged between the core (e.g., 5G core (5GC) or next generation core (NGC)) network and the radio network (RAN). The interface between the CU and the distributed unit (DU) can be called the "F1 interface".

[0056] A centralized unit (CU) can be connected to one or more DUs and can perform functions of upper layers other than the DU. For example, the CU can perform the functions of the radio resource control (RRC) and packet data convergence protocol (PDCP) layers, and the DU and RU can perform the functions of the lower layers. The DU can perform some functions of the radio link control (RLC), media access control (MAC), and physical layer (PHY) (high PHY), and the RU can perform the remaining functions of the PHY layer (low PHY). In addition, for example, depending on the implementation method of the distributed deployment of the base station, the digital unit (DU) can be included in the distributed unit (DU). Hereinafter, although the operations of the digital unit (DU) and the RU will be described unless otherwise defined, the various embodiments can be applied to both the deployment of a base station including a CU and the deployment in which the DU is directly connected to the core network in the absence of a CU (i.e., the CU and the DU are integrated into one entity).

[0057] Figure 2 The configuration of a DU in a wireless communication system according to an embodiment of the present disclosure is shown.

[0058] Figure 2 The configuration shown can be understood as Figure 1BHereinafter, the terms "unit," "device," etc., denote a unit for processing at least one function or operation and may be implemented as hardware, software, or a combination thereof.

[0059] refer to Figure 2 , the DU 160 includes a communication unit 210 , a storage unit 220 , and a controller 230 .

[0060] The communication unit 210 can perform the function of sending and receiving signals in a wired communication environment. The communication unit 210 may include a wired interface for controlling direct connections between devices through a transmission medium (e.g., copper wire or optical fiber). For example, the communication unit 210 can send an electrical signal to another device through a copper wire, or can perform conversion between electrical and optical signals. The communication unit 210 can be connected to a radio unit (RU). The communication unit 210 can be connected to a core network, or can be connected to a CU in a distributed deployment.

[0061] The communication unit 210 can perform the functions of sending and receiving signals in a wireless communication environment. For example, the communication unit 210 can perform the conversion function between the baseband signal and the bit stream according to the physical layer standard of the system. For example, when sending data, the communication unit 210 generates complex symbols by encoding and modulating the sending bit stream. In addition, when receiving data, the communication unit 210 recovers the received bit stream by demodulating and decoding the baseband signal. In addition, the communication unit 210 may include multiple transmit / receive paths. In addition, according to an embodiment, the communication unit 210 may be connected to a core network or may be connected to other nodes (e.g., integrated access backhaul (IAB)).

[0062] Communication unit 210 can transmit and receive signals. To this end, communication unit 210 may include at least one transceiver. For example, communication unit 210 can transmit synchronization signals, reference signals, system information, messages, control messages, streams, control information, data, etc. In addition, communication unit 210 can perform beamforming.

[0063] The communication unit 210 transmits and receives signals as described above. Therefore, all or part of the communication unit 210 may be referred to as a "transmitter," a "receiver," or a "transceiver." Furthermore, in the following description, transmission and reception performed through a radio channel will be used to encompass the operations performed by the communication unit 210 as described above.

[0064] Although not in Figure 2Although not shown in FIG, the communication unit 210 may also include a backhaul communication unit for connecting to the core network or another base station. The backhaul communication unit provides an interface for performing communication with other nodes in the network. That is, the backhaul communication unit converts a bit stream transmitted from the base station to another node such as another access node, another base station, an upper node, or the core network into a physical signal, and converts a physical signal received from another node into a bit stream.

[0065] The storage unit 220 stores data such as basic programs, application programs, and configuration 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 thereof. In addition, the storage unit 220 provides the stored data in response to a request from the controller 230. Depending on the embodiment, the storage unit 220 may store scheduling information (e.g., beam information and antenna port information) and stream information (e.g., eAxC) for each stream.

[0066] The controller 230 controls the overall operation of the DU 160. For example, the controller 230 sends and receives signals via the communication unit 210 (or backhaul communication unit). Furthermore, the controller 230 records data in the storage unit 220 and reads data from the storage unit 220. Furthermore, the controller 230 can execute the functions of the protocol stack required by the communication standard. To this end, the controller 230 may include at least one processor. In some embodiments, the controller 230 may include a control message generator for generating control messages including resource allocation information for scheduling multiple layers and a flow identification unit for sending control messages. The control message generator and the flow identification unit may be a set of instructions or codes stored in the storage unit 230, and may be instructions / code that at least temporarily reside in the controller 230 or in a memory space storing instructions / code, or may be part of the circuitry constituting the controller 230. According to various embodiments, the controller 230 may control the DU 160 to perform operations according to various embodiments described later.

[0067] Figure 2 The configuration of the DU 160 shown is merely exemplary, and the DU implementing various embodiments is not limited thereto. That is, according to various embodiments, some elements may be added to or removed from the above configuration, or some elements therein may be modified.

[0068] Figure 3 The configuration of an RU in a wireless communication system according to an embodiment of the present disclosure is shown.

[0069] Figure 3 The configuration shown can be understood as Figure 1BHereinafter, the terms "unit," "device," etc., represent a unit for processing at least one function or operation and may be implemented as hardware, software, or a combination thereof.

[0070] refer to Figure 3 , the RU 180 includes a communication unit 310 , a storage unit 320 , and a controller 330 .

[0071] The communication unit 310 can perform functions for transmitting and receiving signals through a radio channel. For example, the communication unit 310 up-converts a baseband signal into an RF band signal, transmits the signal through an antenna, and down-converts the RF band signal received through the antenna into a baseband signal. For example, the communication unit 310 may include a transmit filter, a receive filter, an amplifier, a mixer, an oscillator, a digital-to-analog converter (DAC), an analog-to-digital converter (ADC), and the like.

[0072] In addition, the communication unit 310 may include multiple transmit / receive paths. In addition, the communication unit 310 may include an antenna unit. The communication unit 310 may include at least one antenna array including multiple antenna elements. In terms of hardware, the communication unit 310 may be configured as a digital circuit and an analog circuit (e.g., a radio frequency integrated circuit (RFIC)). The digital circuit and the analog circuit may be implemented as a single package. In addition, the communication unit 310 may include multiple RF chains. The communication unit 310 may perform beamforming. The communication unit 310 may apply beamforming weights to the signal according to the configuration of the controller 330 so as to give directionality to the signal to be transmitted / received. According to an embodiment, the communication unit 310 may include a radio frequency (RF) block (or RF unit).

[0073] In addition, the communication unit 310 can send and receive signals. To this end, the communication unit 310 may include at least one transceiver. The communication unit 310 can send downlink signals. Downlink signals may include synchronization signals (SS), reference signals (RS) (e.g., cell-specific reference signals (CRS) and demodulation (DM)-RS), system information (e.g., master information block (MIB), system information block (SIB), residual system information (RMSI), and other system information (OSI)), configuration messages, control information, or downlink data. In addition, the communication unit 310 can receive uplink signals. Uplink signals may include random access-related signals (e.g., random access preamble (RAP), message 1 (Msg1), or message 3 (Msg3)), reference signals (e.g., sounding reference signal (SRS) or DM-RS), and power headroom report (PHR).

[0074] The communication unit 310 transmits and receives signals as described above. Therefore, all or part of the communication unit 310 may be referred to as a "transmitter," a "receiver," or a "transceiver." Furthermore, in the following description, transmission and reception performed via a radio channel will be used to encompass the operations performed by the communication unit 310 as described above.

[0075] The storage unit 320 stores data such as basic programs, application programs, and configuration information for the operation of the RU 180. The storage unit 320 can be configured as a volatile memory, a non-volatile memory, or a combination thereof. In addition, the storage unit 320 provides the stored data in response to a request from the controller 330.

[0076] 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. Furthermore, the controller 330 stores data in the storage unit 320 and reads data from the storage unit 320. Furthermore, the controller 330 may execute the functions of the protocol stack required by the communication standard. To this end, the controller 330 may include at least one processor. The controller 330 may include various modules for performing communication. According to various embodiments, the controller 330 may control the RU 180 to perform operations according to various embodiments described later.

[0077] Figure 4 An example of functional division in a wireless communication system according to an embodiment of the present disclosure is shown.

[0078] The development of wireless communication technology (for example, the introduction of the fifth generation (5G) communication system or the new radio (NR) communication system) has brought about an increase in the used frequency band, and due to the significant reduction in the radius of the base station cell, the number of RUs that need to be installed has further increased. In addition, the amount of data transmitted in the 5G communication system has increased by 10 times or more, so the transmission capacity of the wired network sent through the fronthaul has greatly increased. These factors may lead to a substantial increase in the installation cost of the wired network in the 5G communication system. Therefore, in order to reduce the transmission capacity of the wired network and reduce the installation cost of the wired network, a technology for reducing the transmission capacity of the fronthaul by transferring some functions of the DU's modem to the RU has been proposed, and this technology can be called "functional splitting".

[0079] To reduce the burden on the DU, consideration is being given to expanding the role of the RU, which previously performed only RF functions, to include some physical layer functions. In this scenario, when the RU performs higher-level functions, its throughput increases, which can increase transmission bandwidth in the fronthaul and reduce latency constraints imposed by response procedures. At the same time, when the RU performs higher-level functions, virtualization gains decrease, and the size, weight, and cost of the RU increase. The trade-offs between these advantages and disadvantages must be considered to achieve an optimal functional partition.

[0080] Figure 4 The functional division in the physical layer of the MAC layer or lower layer is shown. In the case of a downlink (DL) that sends a signal to a terminal through a wireless network, the base station can sequentially perform channel coding / scrambling, modulation, layer mapping, antenna mapping, RE mapping, digital beamforming (e.g., precoding), IFFT conversion / CP addition, and RF conversion. In the case of an uplink (UL) that receives a signal from a terminal through a wireless network, the base station can sequentially perform RF conversion, FFT conversion / CP removal, digital beamforming (e.g., precombining), RE demapping, channel estimation, layer demapping, demodulation, and decoding / descrambling. According to the above trade-offs, the division between uplink functions and downlink functions can be defined in various types depending on necessity, discussions between vendors on specifications, and the like.

[0081] refer to Figure 4, the first functional partition 405 can be a partition between RF functions and PHY functions. The first functional partition is intended to enable the PHY functions to be basically not implemented in the RU, and can be referred to as, for example, "Option 8". The second functional partition 410 can enable the RU to perform, among the PHY functions, IFFT conversion / CP addition in DL and FFT conversion / CP removal in UL, and can enable the DU to perform the remaining PHY functions. For example, the second functional partition 410 can be referred to as "Option 7-1". The third functional partition 420a can enable the RU to perform, among the PHY functions, IFFT conversion / CP addition in DL and FFT conversion / CP removal in UL and digital beamforming, and can enable the DU to perform the remaining PHY functions. For example, the third functional partition 420a can be referred to as "Option 7-2x Category A". The fourth functional partition 420b can enable the RU to perform digital beamforming in both DL and UL, and can enable the DU to perform more PHY functions after digital beamforming. For example, the fourth functional partition 420b can be referred to as "Option 7-2x Category B". The fifth functional division 425 may enable the RU to perform RE mapping (or RE demapping) in both DL and UL, and may enable the DU to perform further PHY functions after RE mapping (or RE demapping). For example, the fifth functional division 425 may be referred to as "option 7-2". The sixth functional division 430 may enable the RU to perform modulation (or demodulation) in both DL and UL, and may enable the DU to perform further PHY functions after modulation (or demodulation). For example, the sixth functional division 430 may be referred to as "option 7-3". The seventh functional division 440 may enable the RU to perform encoding / scrambling (or decoding / descrambling) in both DL and UL, and may enable the DU to perform further PHY functions after modulation (or demodulation). For example, the seventh functional division 440 may be referred to as "option 6".

[0082] According to an embodiment, if it is expected to process large-capacity signals (such as the FR1 MMU), functional division in a relatively higher layer (e.g., the fourth functional division 420b) may be required to reduce the capacity of the fronthaul. In addition, functional division in an excessively high layer (e.g., the sixth functional division 430) may require a complex control interface and may burden the RU implementation because multiple PHY processing blocks are included in the RU. Therefore, depending on the deployment and implementation of the DU and RU, appropriate functional division may be required.

[0083] According to an embodiment, if the precoding of the data received from the DU cannot be processed (i.e., if the RU has limited precoding capabilities), the third functional partition 420a or the functional partition below it (e.g., the second functional partition 410) may be applied. On the other hand, if the precoding of the data received from the DU can be processed, the fourth functional partition 420b or the functional partition above it (e.g., the sixth functional partition 430) may be applied. Hereinafter, although various embodiments will be described based on the third functional partition 420a or the fourth functional partition 420b unless otherwise specified in this disclosure, this is not intended to exclude the configuration of embodiments through other functional partitions. For example, the embodiment to be described below may be applied to the case of the sixth functional partition 430 (option 7-3).

[0084] Figure 5 An example of a beam that can be formed in an RU of a base station in a wireless communication system according to an embodiment of the present disclosure is shown.

[0085] refer to Figure 5 , the RU includes an antenna array 510 including a plurality of antenna elements. The RU can perform beamforming using the antenna array 510. 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 from each other. 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 may be related to the number of RF chains of the RU.

[0086] For example, in the case where three beams such as the first beam 520a, the second beam 520b, and the third beam 520c can be formed simultaneously, the beams can be applied to corresponding resources as follows: Figure 6 shown.

[0087] Figure 6 An example of a resource element (RE) mask in a wireless communication system according to an embodiment of the present disclosure is shown.

[0088] Figure 6 A case where three beams are used in a resource region including 14 symbols and 12 REs is shown. Figure 6 The resource regions shown may be referred to as “sections”, “resource blocks (RBs)” or other terms having equivalent technical meanings.

[0089] The RU maps the beam to the resource according to the control of the DU. In other words, the RU transmits the signal transmitted through the resource through the beam under the control of the DU. In this case, one segment can be mapped to a single beam. However, the beam to be applied may be different between resources belonging to one RB or one segment. For example, referring to Figure 6 , the first beam may be mapped to REs 600, 601, 602, 603, 604, 605, 607, 608, and 610 with indices 0 to 5, 7, 8, and 10, the second beam may be mapped to REs 606 and 609 with indices 6 and 9, and the third beam may be mapped to RE 611 with index 11. In other words, beamforming may be performed such that signals mapped to the 2nd, 5th, and 8th subcarriers are transmitted through the first beam, signals mapped to the 6th and 9th subcarriers are transmitted through the second beam, and signals mapped to the 11th subcarrier are transmitted through the third beam. In this case, since one partition is mapped to a single beam, a masking method may be used to indicate that beams are mapped to some resources (e.g., REs or carriers) in one partition.

[0090] For example, the DU may indicate that the first beam is mapped to Figure 6 The segment shown provides a mask value of "111111011010" for the first beam. 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 can be expressed as "reMask_B," and the mask for the third beam can be expressed as "reMask_C." The exclusive OR (XOR) operation of the three listed mask values results in "111111111111."

[0091] Using the above-mentioned mask value, the RU can determine the REs or subcarriers among the REs in the segments to which the first beam, the second beam, and the third beam are applied based on the bit pattern of the mask value. The RU can allocate a memory space for storing at least one mask value received from the DU, and can store at least one mask value in the allocated memory space. Thereafter, in the case of transmitting a signal through the segment, the RU can use the mask value and the beam information to perform beamforming for the corresponding RE. In this case, the mask value can be stored so as to be paired with the segment information (e.g., a segment identifier (ID)). For example, if Figure 6 If three masks are received, you may need Figure 7 The memory space shown.

[0092] Figure 7An example of a memory space for storing mask values in a wireless communication system according to an embodiment of the present disclosure is shown.

[0093] refer to Figure 7 , first space 701 is allocated to store the segment ID value and mask value of the first beam, second space 702 is allocated to store the segment ID value and mask value of the second beam, and third space 703 is allocated to store the segment ID value and mask value of the third beam. In other words, if three mask values are received, memory space is required to store at least three mask values and three segment ID values.

[0094] At the same time, the DU uses control signaling to control the RU. Control messages received from the DU are stored in the RU and then decoded. In this case, C-plane messages can be stored in units of a specific time (e.g., one time slot or 14 symbols). If a number of messages exceeding the available memory capacity of the RU is received within a specific time unit, some of the messages may be lost and their decoding may fail. Here, the control message sent from the DU may be a control (C) plane message.

[0095] To prevent the situation where the number of messages sent exceeds the available memory capacity, the RU can report the available memory capacity to the DU. Therefore, the DU can send control messages taking into account the available memory capacity of the RU. In this case, the message sent from the RU can be a management (M) plane message.

[0096] If there is no operation to indicate the available memory capacity of the RU, the DU can send control messages without considering the available memory capacity of the RU. In this case, the RU is required to allocate memory space based on the maximum size of the message that can be sent by the DU. For example, in the case of RE masking, since 12 REs are included in one segment, it is expected that a control message including up to 12 mask values can be received. Preparing for up to 12 mask values and ensuring memory space for storing up to 12 mask values may lead to an increase in RU implementation costs.

[0097] Furthermore, securing memory space for storing 12 mask values may result in unnecessary waste of memory space. In the downlink channel currently defined in the fifth generation (5G) New Radio (NR) standard, the downlink combinations that can be assigned to one segment may not be infinite. The combinations shown in Table 1 can be considered, although they may vary depending on the specific implementation.

[0098]

Table 1

[0099] Channel combination Number of channels 1 PDSCH+PDSCH DMRS 2 2 PDSCH+PT-RS 2 3 PDSCH+CSI-RS 2 4 PDSCH DMRS+CSI-RS 2 5 PDSCH+PDSCH DMRS+CSI-RS 3 6 PDSCH+PT-RS+CSI-RS 3 7 DMRS for PDSCH+PDCCH 2 8 SSS+PBCH 2

[0100] Considering the combinations shown in Table 1 above, the maximum number of transmittable channels in one sector is 3. In this case, securing memory space for storing four or more mask values may result in a waste of memory space because no more than three beams are used in one sector.

[0101] Furthermore, if there is no operation to indicate the available memory capacity of the RU, the DU may send a message whose size exceeds the available memory capacity of the RU. In this case, at least a portion of the message may not be stored, and its decoding may fail. For example, if the DU sends a control message including three mask values while the RU has guaranteed memory space to store only two mask values, decoding of the control message may fail.

[0102] Figure 8 is a flowchart illustrating the operation of an RU in a wireless communication system according to an embodiment of the present disclosure.

[0103] Figure 8 A method of operating the RU 180 of the base station 110 is shown.

[0104] refer to Figure 8 In method 800, in operation 801, the RU transmits a message including a value indicating the maximum number of RE masks. Here, the maximum number of RE masks can be understood as the number of pairs between mask values and segment ID values that can be stored in the RU. That is, the RU transmits a value corresponding to the capacity of the memory space that can be allocated for storing RE mask values in the memory to the DU.

[0105] In operation 803, the RU may receive a message for controlling the RU. The RU may store the received message in a memory space. For example, the message may include scheduling information associated with the RU's operation. Specifically, the message may include at least one RE mask value. The RU may obtain information included in the message by decoding the message stored in the memory space.

[0106] Figure 9 is a flowchart illustrating an operation of a digital unit (DU) in a wireless communication system according to an embodiment of the present disclosure.

[0107] Figure 9 A method of operating the DU 170 of the base station 110 is shown.

[0108] refer to Figure 9In method 900, in operation 901, the DU receives a message from the RU including a value indicating the maximum number of RE masks. Here, the maximum number of RE masks can be understood as the number of pairs between mask values and segment ID values that the RU can store. That is, the DU receives a value corresponding to the capacity of the memory space that can be allocated for storing RE mask values in the memory from the RU.

[0109] In operation 903, the DU transmits a message for controlling the RU. For example, the message may include scheduling information associated with the operation of the RU. In this case, 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 so that beams exceeding the number of RE masks corresponding to the value received in operation 901 are not used in one segment.

[0110] Figure 10 Schematic diagram illustrating signal exchange between a DU and a RU in a wireless communication system according to an embodiment of the present disclosure.

[0111] Figure 10 Shown Figure 8 The operation of RU 180 is shown and Figure 9 A specific example of the operation of DU 160 is shown.

[0112] refer to Figure 10 RU 180 may transmit an M-plane message 1002 to DU 160. M-plane message 1002 may include information regarding the status or resources of RU 180. For example, 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. M-plane message 1002 may be transmitted during or after the process of establishing an initial connection between RU 180 and DU 160. Thereafter, DU 160 may transmit a C-plane message 1004 for controlling the operation of RU 180. For example, C-plane message 1004 may include scheduling information (e.g., RE mask) for the operation of RU 180.

[0113] exist Figure 10 In the process shown, the M-plane message 1002 may also include the information shown in Table 2 below.

[0114]

Table 2

[0115]

[0116]

[0117] exist Figure 10 In the process shown, the C-plane message 1004 may be configured as shown in Table 3, Table 4, Table 5, or Table 6 below.

[0118]

Table 3

[0119]

[0120]

[0121]

[0122] In Table 3, the value of the parameter "ef" of the octet 23 determines whether segment extension is performed. If "ef=0", segment extension is not performed, and if "ef=1", segment extension is performed, that is, "reMask" is added. In other words, segment extension can be performed to add "reMask". In this case, when generating and transmitting the C-plane message, the DU performs segment extension in consideration of the available memory capacity of the RU. For example, if segment extension is not performed even once, the octet 23 includes "ef=0", the octet 21 and the octet 22 include "reMask=111111111111", which indicates that only one beam is used in the corresponding segment.

[0123] According to the segment type, the message structure in Table 3 can be changed to the message structure shown in the following Table 4 or 5. Table 4 shows a message according to segment type "0", Table 5 shows a message according to segment type "1", and Table 6 shows a message according to segment type "3".

[0124]

Table 4

[0125]

[0126]

[0127]

[0128]

[0129]

Table 5

[0130]

[0131]

[0132]

[0133]

Table 6

[0134]

[0135]

[0136]

[0137] As described in various embodiments above, the RU provides the DU with information about the maximum number of storable RE masks so that the control message can be generated and sent within the available memory capacity of the RU. That is, the information about the maximum number of RE masks can be understood as a value indicating information about the available memory capacity.

[0138] Therefore, according to another embodiment, the maximum number of RE masks can be replaced with information that explicitly or implicitly indicates the available memory capacity. The available memory capacity to be signaled can be the total available memory capacity for storing control messages, or can be the available memory capacity that can be allocated to a specific information item (e.g., RE mask value). The specific information item can be information about the RE mask or other information.

[0139] In addition, according to another embodiment, the value indicating the maximum number of RE masks can be replaced with a value related to the number of other parameters besides the RE mask. Since the number of RE masks can be repeatedly included in the control message, the maximum number of RE masks can affect the memory capacity. Therefore, the number of other parameters that can be repeatedly included in the control message can be reported in parallel with the RE mask or as a replacement. However, even for non-repeated parameters, information indicating whether memory space is allocated for storing the parameter can be reported. In other words, a value indicating its presence or absence can be used instead of its number.

[0140] The methods disclosed in the claims and / or the methods according to various embodiments described in this disclosure may be implemented by hardware, software, or a combination of hardware and software.

[0141] When the method is implemented by software, a computer-readable storage medium for storing one or more programs (software modules) can be provided. The one or more programs stored in the computer-readable storage medium can be configured to be executed by one or more processors within the electronic device. At least one program may include instructions that cause the electronic device to perform the method according to the various embodiments of the present disclosure defined by the appended claims and / or disclosed herein.

[0142] The program (software module or software) may be stored in a non-volatile memory (including random access memory and flash memory, read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), magnetic disk storage, compact disk read-only memory (CD-ROM), digital versatile disk (DVD) or other types of optical storage devices or cassette tapes). Alternatively, any combination of some or all of them may form the memory in which the program is stored. In addition, a plurality of such memories may be included in the electronic device.

[0143] In addition, the program can be stored in an attachable storage device that can access the electronic device through a communication network (such as the Internet, an intranet, a local area network (LAN), a wide area LAN (WLAN), and a storage area network (SAN), or a combination thereof. Such a storage device can access the electronic device through an external port. In addition, a separate storage device on a communication network can access the portable electronic device.

[0144] In the above detailed embodiments of the present disclosure, the elements included in the present disclosure are expressed in the singular or plural, depending on the detailed embodiment presented. However, for ease of description, the singular or plural form is appropriately selected for the presented situation, and the present disclosure is not limited to elements expressed in the singular or plural. Therefore, an element expressed in the plural may also include a single element, or an element expressed in the singular may also include multiple elements.

[0145] While the disclosure has been shown and described with reference to various embodiments, it will be understood by those skilled in the art that various changes in form and details may be made without departing from the spirit and scope of the disclosure as defined by the appended claims and their equivalents.

Claims

1. A method performed by a radio unit (RU) in a wireless communication system, the method comprising: sending a first message to a digital unit DU, the first message comprising a value indicating a maximum number of resource element RE masks of a segment; as well as receiving a second message generated based on the value from the DU, wherein the maximum number of RE masks for the segment is the number of at least one pair of RE masks and segment identifiers ID that can be stored in the RU, and The RE mask indicates at least one RE associated with a beam in the segment.

2. The method according to claim 1, further comprising: At least one value of the RE mask included in the second message is stored in units of time.

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

4. The method according to claim 1, in, The first message further includes at least one of a value indicating a maximum number of segments per symbol or a value indicating a maximum number of segments per slot, and The second message includes a value indicating the number of RE masks that is equal to or smaller than the maximum number of RE masks.

5. The method according to claim 1, wherein The first message is sent during the process of establishing an initial connection between the RU and the DU.

6. The method according to claim 1, in, The first message includes a management plane (M-plane) message, The second message includes a control plane (C-plane) message and includes segment extension information, and The segment extension information includes information indicating the RE mask and is associated with one of segment type 0, segment type 1 or segment type 3.

7. A method performed by a digital unit (DU) in a wireless communication system, the method comprising: receiving a first message from a radio unit RU, the first message comprising a value indicating a maximum number of resource elements RE mask of a segment; as well as sending a second message generated based on the value to the DU, wherein the maximum number of RE masks for the segment is the number of at least one pair of RE masks and segment identifiers ID that can be stored in the RU, and The RE mask indicates at least one RE associated with a beam in the segment.

8. The method according to claim 7, wherein: The second message is based on an available memory capacity of the RU.

9. The method according to claim 7, in, The first message further includes at least one of a value indicating a maximum number of segments per symbol or a value indicating a maximum number of segments per slot, and The second message includes a value indicating the number of RE masks that is equal to or smaller than the maximum number of RE masks.

10. The method according to claim 7, wherein: The first message is received during a process of establishing an initial connection between the RU and the DU.

11. The method according to claim 7, in, The first message includes a management plane (M-plane) message, The second message includes a control plane (C-plane) message and includes segment extension information, and The segment extension information includes information indicating the RE mask and is associated with one of segment type 0, segment type 1 or segment type 3.

12. The method according to claim 7, further comprising: A value indicating the maximum number of RE masks for the segment is stored.

13. A radio unit (RU) in a wireless communication system, the RU comprising: transceiver; one or more processors; A memory, coupled to the transceiver and the one or more processors, stores instructions executable by the one or more processors individually or collectively to cause the RU to implement one of claims 1 to 6.

14. A digital unit (DU) in a wireless communication system, the DU comprising: transceiver; one or more processors; A memory, coupled to the transceiver and the one or more processors, stores instructions executable by the one or more processors, individually or collectively, to cause the DU to implement one of claims 7 to 12.

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