Electronic device and method for providing frequency offset in fronthaul interface

Abstract

According to an embodiment, a method performed by a radio frequency unit (RU) may include an operation of receiving a control plane (C plane) message including frame structure information for indicating frequency offset information and subcarrier spacing (SCS) from a distributed unit (DU). The method may include an operation of identifying a frequency offset factor among a plurality of frequency offset factors. The method may include an operation of obtaining a frequency offset value corresponding to a product of the frequency offset information, the SCS, and the frequency offset factor. The method may include transmitting a downlink signal based on the frequency offset value. The plurality of frequency offset factors may include "0.5" and "0.25".

Description

Technical Field

[0001] The present disclosure generally relates to fronthaul interfaces. More specifically, the present disclosure relates to electronic devices and methods for providing frequency offset in fronthaul interfaces. Background Art

[0002] As transmission capacity increases in wireless communication systems, a function split that functionally separates base stations is applied. According to such a function split, a base station can be divided into a distributed unit (DU) and a radio unit (RU). A fronthaul interface is generally defined for communication between the DU and the RU.

[0003] The above information is presented 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 information may be applicable as prior art with respect to the present disclosure. Summary of the invention

[0004] Technical Solution According to an embodiment, a method performed by a radio unit (RU) may include: receiving a control plane (C-plane) message including frequency offset information and frame structure information indicating a subcarrier spacing (SCS) from a distributed unit (DU). The method may include identifying a frequency offset factor among a plurality of frequency offset factors. The method may include acquiring a frequency offset value corresponding to a product of the frequency offset information, the SCS, and the frequency offset factor. The method may include sending a downlink signal based on the frequency offset value. The plurality of frequency offset factors may include "0.5" and "0.25".

[0005] According to an embodiment, a method performed by a distributed unit (DU) may include: determining frequency offset information related to a frequency offset factor among a plurality of frequency offset factors. The method may include sending a control plane (C-plane) message including segment information for a downlink signal, the frequency offset information, and frame structure information indicating a subcarrier spacing (SCS) to a radio frequency unit (RU). The frequency offset factor may be provided to the RU by a management plane (M-plane) message or the C-plane message. The frequency offset value applied to the downlink signal may correspond to the product of the frequency offset information, the SCS, and the frequency offset factor. The plurality of frequency offset factors may include "0.5" and "0.25".

[0006] According to an embodiment, an electronic device of a radio frequency unit (RU) may include: at least one fronthaul transceiver; at least one radio frequency (RF) transceiver; at least one processor coupled to the at least one fronthaul transceiver and the at least one RF transceiver. The at least one processor may be configured to receive a control plane (C-plane) message including frequency offset information and frame structure information indicating a subcarrier spacing (SCS) from a distributed unit (DU). The at least one processor may be configured to identify a frequency offset factor among a plurality of frequency offset factors. The at least one processor may be configured to obtain a frequency offset value corresponding to a product of the frequency offset information, the SCS, and the frequency offset factor. The at least one processor may be configured to send a downlink signal based on the frequency offset value. The plurality of frequency offset factors may include "0.5" and "0.25".

[0007] According to an embodiment, an electronic device of a distributed unit (DU) may include at least one transceiver and at least one processor coupled to the at least one transceiver. The at least one processor may be configured to determine frequency offset information related to a frequency offset factor among a plurality of frequency offset factors. The at least one processor may be configured to send a control plane (C-plane) message including segment information for a downlink signal, the frequency offset information, and frame structure information for indicating a subcarrier spacing (SCS) to a radio frequency unit (RU). The frequency offset factor may be provided to the RU by a management plane (M-plane) message or the C-plane message. The frequency offset value applied to the downlink signal may correspond to the product of the frequency offset information, the SCS, and the frequency offset factor. The plurality of frequency offset factors may include "0.5" and "0.25". BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1 A wireless communication system according to an embodiment is shown.

[0009] Figure 2a A fronthaul interface according to an embodiment is shown.

[0010] Figure 2b An open radio access network (O-RAN) fronthaul interface according to an embodiment is shown.

[0011] Figure 3a A functional configuration of a distributed unit (DU) according to an embodiment is shown.

[0012] Figure 3b A functional configuration of a radio frequency unit (RU) according to an embodiment is shown.

[0013] Figure 4An example of functional division between DU and RU according to an embodiment is shown.

[0014] Figure 5 The difference in grid units between ARFCN (Absolute Radio Frequency Channel Number) and GSCN (Global Synchronization Channel Number) according to an embodiment is shown.

[0015] Figure 6 An example of offset compensation of a synchronization signal block (SSB) having a center frequency different from the center frequency of the bandwidth according to an embodiment is shown.

[0016] Figure 7 An example of a control plane (C-plane) message according to an embodiment is shown.

[0017] Figure 8 An example of section extension information according to an embodiment is shown.

[0018] Figure 9a An example is shown for signaling between a DU and a RU using a frequency offset factor through a management plane (M-plane) message and a C-plane message to provide a frequency offset according to an embodiment.

[0019] Figure 9b An example is shown for signaling between the DU and the RU using a frequency offset factor through a C-plane message to provide a frequency offset according to an embodiment.

[0020] Fig.10 An example of signal processing of RUs in a hybrid parameter set channel according to an embodiment is shown. DETAILED DESCRIPTION

[0021] Hereinafter, the terms used in the present disclosure are only used to better describe a certain embodiment, and may not be intended to limit the scope of other embodiments. Singular expressions may include plural expressions, unless the context clearly stipulates otherwise. The terms used herein (including technical terms and scientific terms) may have the same meaning as the meanings generally understood by those skilled in the art to which the present disclosure belongs. The terms defined in the general dictionary among the terms used in the present disclosure may be interpreted as having the same or similar meanings as those in the context of the relevant field, and unless clearly defined in the present disclosure, they are not interpreted as ideal or overly formal meanings. In some cases, even the terms defined in the present disclosure may not be interpreted as excluding embodiments of the present disclosure.

[0022] In various examples of the present disclosure described below, a hardware method will be described as an example. However, since various embodiments of the present disclosure may include techniques utilizing both hardware-based methods and software-based methods, the various embodiments are not intended to exclude software-based methods.

[0023] As used in the following description, terms referring to a combination (e.g., merge, group, combine, aggregate, join, integrate, unify), terms referring to a signal (e.g., packet, message, signal, information, signaling), terms referring to a resource (e.g., segment, symbol, slot, subframe, radio frame, subcarrier, resource element (RE), resource block (RB), bandwidth part (BWP), opportunity), terms referring to an operating state (e.g., step, operation, process), terms referring to data (e.g., packet, message, user stream, information, bit, symbol, symbol, codeword), ), terms referring to channels, terms referring to network entities (e.g., distributed unit (DU), radio unit (RU), control unit (CU), control plane (CU-CP), user plane (CU-UP), O-DU (O-RAN (Open Radio Access Network) DU), O-RU (O-RANRU), O-CU (O-RANCU), O-CU-UP (O-RANCU-CP), O-CU-CP (O-CU-CP)), terms referring to components of a device, etc. are exemplified for ease of explanation. Therefore, the present disclosure is not limited to the terms described below, and other terms with equivalent technical meanings may be used for this purpose. In addition, as used hereinafter, terms such as, for example, "~part", "~section", "~unit", "~module", "~main body", etc. may refer to at least one shape of a structure or unit for processing a specific function.

[0024] Throughout this disclosure, expressions such as "greater than" or "less than" may be used to determine whether a particular condition is met or completed, but it is merely a description for expressing an example and is not intended to exclude the meaning of "greater than or equal to" or "less than or equal to". A condition described as "greater than or equal to" may be replaced with "greater than", a condition described as "less than or equal to" may be replaced with "less than", and a condition described as "greater than or equal to and less than" may be replaced with "greater than and less than or equal to", respectively. In addition, hereinafter, "A" to "B" may refer to at least one of the elements from A (including A) to B (including B). hereinafter, "C" and / or "D" may refer to at least one of "C" or "D", i.e., {"C", "D" or "C" and "D"}.

[0025] Although the present disclosure uses terms used in some communication standards (e.g., 3GPP (3rd Generation Partnership Project), xRAN (Extensible Radio Access Network), O-RAN (Open Radio Access Network)) to describe various embodiments, they are only examples for description. Various embodiments of the present disclosure can be easily modified and applied to other communication systems.

[0026] The present disclosure provides electronic devices and methods for providing more accurate units of frequency offset.

[0027] In addition, the present disclosure provides an apparatus and method for adaptively adjusting a frequency offset factor, which is a unit for expressing a frequency offset on a fronthaul interface.

[0028] In addition, the present disclosure provides an electronic device and method for compensating for the difference in grid units between ARFCN (Absolute Radio Frequency Channel Number) and GSCN (Global Synchronization Channel Number) on a fronthaul interface.

[0029] In addition, the present disclosure provides an apparatus and method for providing a frequency offset factor through a management plane (M-plane) message on a fronthaul interface.

[0030] In addition, the present disclosure provides an apparatus and method for providing a frequency offset factor through a control plane (C-plane) message on a fronthaul interface.

[0031] According to the electronic device and method of the embodiments of the present disclosure, by adaptively adjusting the frequency offset factor on the fronthaul interface, a numerology can more accurately compensate for the frequency offset between channels with different numerologies.

[0032] Effects that can be obtained by the present disclosure are not limited to the above-mentioned effects, and other effects not mentioned herein can be clearly understood from the following description by a person having ordinary knowledge in the technical field to which the present disclosure belongs.

[0033] Figure 1 A wireless communication system according to an embodiment is shown.

[0034] Reference Figure 1 , Figure 1 A base station 110 and a terminal 120 are shown as a part of a node using a wireless channel in a wireless communication system. Figure 1 Only one base station is shown, but the wireless communication system may also include another base station that is the same as or similar to the base station 110 .

[0035] The base station 110 is a network infrastructure for providing wireless access to the terminal 120. The base station 110 has a coverage range defined based on the distance at which a signal can be transmitted. In addition to the term "base station", the base station 110 may also be referred to as an "access point (AP)", "eNodeB (eNB)", "fifth generation node (5G node)", "next generation node B (gNB)", "radio point", "transmission / reception point (TRP)" or other terms having technical meanings equivalent thereto.

[0036] The terminal 120 is a device used by a user and performs communication with the base station 110 through a wireless channel. A link from the base station 110 to the terminal 120 is called a downlink (DL), and a link from the terminal 120 to the base station 110 is called an uplink (UL). Figure 1 Although not shown in the figure, the terminal 120 and another terminal may perform communication with each other through a wireless channel. In this case, the device-to-device (D2D) link between the terminal 120 and another terminal may be referred to as a side link, and the side link may be used interchangeably with the PC5 interface. In some other embodiments, the terminal 120 may operate without any user involvement. According to an embodiment, the terminal 120 is a device that performs machine type communication (MTC) and may not be carried by a user. In addition, according to an embodiment, the terminal 120 may be a narrowband (NB) Internet of Things (IoT) device.

[0037] In addition to the term "terminal", terminal 120 may be referred to as "user equipment (UE)", "customer premises equipment (CPE)", "mobile station", "subscriber station", "remote terminal", "wireless terminal", "electronic device", "user device" or other terms having substantially the same technical meaning as those.

[0038] The base station 110 may perform beamforming with the terminal 120. The base station 110 and the terminal 120 may transmit and receive wireless signals in a relatively low frequency band, such as frequency range 1 (FR 1) of NR. In addition, the base station 110 and the terminal 120 may transmit and receive wireless signals in a relatively high frequency band, such as FR 2 (or FR 2-1 and FR 2-1) of NR and millimeter wave bands (e.g., 28 GHz, 30 GHz, 38 GHz, and 60 GHz). In order to improve channel gain, the base station 110 and the terminal 120 may perform beamforming. Here, beamforming may include transmit beamforming and receive beamforming. The base station 110 and the terminal 120 may assign directivity to a transmit signal or a receive signal. To this end, the base station 110 and the terminal 120 may select a service beam through a beam search or a beam management process. After selecting the service beam, subsequent communication may be performed using a resource having a QCL relationship with a resource to which the service beam has been transmitted.

[0039] If large-scale characteristics of a channel carrying symbols on a first antenna port can be inferred from a channel carrying symbols on a second antenna port, the first antenna port and the second antenna port can be evaluated as a QCL relationship. For example, the large-scale characteristics may include at least one of delay spread, Doppler spread, Doppler shift, average gain, average delay, and spatial receiver parameters.

[0040] Although Figure 1It is shown that both the base station 110 and the terminal 120 perform beamforming, but the embodiments of the present disclosure are not necessarily limited thereto. In some embodiments, the terminal may or may not perform beamforming. In addition, the base station may or may not perform beamforming. That is, only one of the base station and the terminal may perform beamforming, or both the base station and the terminal may not perform beamforming.

[0041] In the present disclosure, the term "beam" refers to a spatial stream of a signal in a wireless channel, and may be formed by one or more antennas (or antenna elements), and the formation process may be referred to as beamforming. Beamforming may include at least one of analog beamforming or digital beamforming (e.g., precoding). For example, reference signals transmitted based on beamforming may include 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, for example, CSI-RS resources or SRS resources may be used as configurations for each reference signal, and such configurations may include information associated with the beam. The information associated with the beam may mean whether the corresponding configuration (e.g., CSI-RS resource) uses the same spatial domain filter as another configuration (e.g., other CSI-RS resources in the same CSI-RS resource set) or a different spatial domain filter, or with which reference signal it is quasi-co-located (QCLed), and if QCLed, what type (e.g., QCL type A, B, C, or D).

[0042] In a conventional communication system having a relatively large cell radius of a base station, each base station is installed such that the base station includes the functions of a digital processing unit (or distributed unit, DU) and a radio frequency (RF) processing unit (or radio frequency unit, RU). However, as high frequency bands are used in 4G (fourth generation) systems and / or subsequent communication systems (e.g., 5G), and the cell coverage of base stations is reduced, the number of base stations used to cover a specific area increases. The installation cost burden of operators installing these base stations has also increased. In order to minimize the installation cost of the base station, a structure has been proposed in which the DU and RU are separated from one or more RUs connected to one DU through a wired network, and one or more topologically distributed RUs are arranged to cover a specific area. In the following, reference is made to Figure 2a to Figure 2b Describe examples of deployment structures and extensions of base stations according to various embodiments of the present disclosure.

[0043] Figure 2a 1 shows a fronthaul interface according to an embodiment. Unlike the backhaul between the base station and the core network, the fronthaul refers to the entities between the radio access network (RAN) and the base station. Figure 2aAn example of a forward haul structure between one RU 220 and one DU 210 is shown, but it is only for ease of description, and the present disclosure is not limited thereto. In other words, the embodiments of the present disclosure may be applied to a forward haul structure between one DU and multiple RUs. For example, the embodiments of the present disclosure may be applied to a forward haul structure between one DU and two RUs. In addition, the embodiments of the present disclosure may be applied to a forward haul structure between one DU and three RUs.

[0044] Reference Figure 2a , the base station 110 may include a DU 210 and a RU 220. A fronthaul 215 between the DU 210 and the RU 220 may be operated via an Fx interface. For the operation of the fronthaul 215, for example, an interface such as an enhanced common radio interface (eCPRI), a radio over Ethernet (ROE), etc. may be used.

[0045] With the further development of communication technology, mobile data services have increased, and then the bandwidth requirements required for fronthaul between digital units and radio frequency units have increased significantly. In deployments such as centralized / cloud radio access networks (C-RAN), DU can be implemented to perform functions for packet data convergence protocol (PDCP), radio link control (RLC), medium access control (MAC), and physical (PHY), and in addition to radio frequency (RF) functions, RU can also be implemented to perform functions for the PHY layer.

[0046] DU 210 may be responsible for the upper layer functions of the wireless network. For example, DU 210 may perform the functions of the MAC layer and a part of the PHY layer. Here, a part of the PHY layer performed at a relatively high level of the functions of the PHY layer may include, for example, channel coding (or channel decoding), scrambling (or descrambling), modulation (or demodulation), layer mapping (or layer demapping), etc. According to an embodiment, when DU 210 complies with the O-RAN standard, it may be referred to as O-RAN DU (O-DU). In an embodiment of the present disclosure, DU 210 may be represented as being replaced with a first network entity of a base station (e.g., gNB) as needed.

[0047] The RU 220 may be responsible for lower layer functions of the wireless network. For example, the RU 220 may perform a portion of the PHY layer and an RF function. Here, a portion of the PHY layer performed at a relatively lower level than the DU 210 of the functions of the PHY layer may include, for example, inverse fast forward transform (iFFT) (or fast forward transform (FFT)), cyclic prefix (CP) addition (or CP removal), and digital beamforming. Figure 4, an example of this specific functional split will be described in more detail. RU 220 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 technical meanings equivalent thereto. According to an embodiment, when RU 220 complies with the O-RAN standard, it may be referred to as an O-RAN RU (O-RU). In an embodiment of the present disclosure, RU 220 may be replaced with a second network entity of a base station (e.g., gNB) as needed.

[0048] Although Figure 2a The base station 110 is described as including the DU 210 and the RU 220, but the embodiments of the present disclosure are not limited thereto. The base station according to the embodiment may be implemented in a distributed deployment based on a centralized unit (CU) configured to perform functions of a higher layer of an additional network (e.g., packet data convergence protocol (PDCP), radio resource control (RRC)) and a distributed unit (DU) configured to perform functions of a lower layer. In this case, the distributed unit (DU) may include Figure 1 The base station may be implemented in a structure in which the CU, DU, and RU are arranged in sequence between the core (e.g., 5G core (5GC) or next generation core (NGC)) network and the radio access network (RAN). The interface between the CU and the distributed unit (DU) may be referred to as an F1 interface.

[0049] A centralized unit (CU) may be connected to one or more DUs to be responsible for functions at a higher layer than the DU. For example, the CU may be responsible for functions of the radio resource control (RRC) and packet data convergence protocol (PDCP) layers, and the DU and RU may be responsible for functions of lower layers. The DU may perform some functions of the radio link control (RLC), media access control (MAC), and physical (PHY) layers (e.g., high PHY), and the RU may be responsible for the remaining functions of the PHY layer (e.g., low PHY). In addition, for example, depending on the implementation of a distributed deployment of a base station, a digital unit (DU) may be included in a distributed unit (DU). In the following, unless otherwise defined, the operations of the digital unit (DU) and the RU are described, but various embodiments of the present disclosure may be applied to any one of a base station deployment including a CU or a deployment in which the DU is directly connected to a core network (i.e., the CU and the DU are implemented as entities integrated into one base station (e.g., an NG-RAN node)).

[0050] Figure 2b A fronthaul interface of an open radio access network (O-RAN) according to an embodiment is shown. An eNB or gNB is shown as a base station 110 in a distributed deployment.

[0051] Reference Figure 2b , the base station 110 may include an O-DU 251 and O-RUs 253-1, ..., 253-n. Hereinafter, for ease of description, the operation and function of the O-RU 253-1 may be understood as a description of each other O-RU (eg, O-RU 253-n).

[0052] DU 251 is comprised of the following Figure 4 The O-DU 251 may control the operations of the O-RUs 253-1, ..., 253-n. The O-DU 251 may be referred to as a lower layer segmentation (LLS) centralized unit (CU). The O-RU 253-1 is a logical node including functions of a base station (e.g., eNB, gNB) other than functions specifically assigned to the O-RU 253-1. The O-DU 251 may control the operations of the O-RUs 253-1, ..., 253-n. The O-DU 251 may be referred to as a lower layer segmentation (LLS) centralized unit (CU). The O-RU 253-1 is a node including functions described below. Figure 4 A logical node that performs a subset of the functionality of a base station (e.g., eNB, gNB). The real-time aspects of control plane communication and user plane communication with the O-RU 253-1 can be controlled by the O-DU 251.

[0053] DU 251 can communicate with O-RU 253-1 via an LLS interface. The LLS interface corresponds to a fronthaul interface. The LLS interface refers to a logical interface between O-DU 251 and O-RU 253-1 using lower layer functional splitting (i.e., based on functional splitting within PHY). LLS-C between O-DU 251 and O-RU 253-1 provides a C-plane through the LLS interface. LLS-U between O-DU 251 and O-RU 253-1 provides a U-plane through the LLS interface.

[0054] exist Figure 2b In the present disclosure, the entities of the base station 110 have been described as O-DU and O-RU in order to describe the O-RAN. However, this name should not be construed as limiting the embodiments of the present disclosure. Figures 3a to 9b In the described embodiments, it will be appreciated that the operations of DU 210 may be performed by O-DU 251. The description of DU 210 may be applied to O-DU 251. Figures 3a to 9b In the described embodiment, it will be appreciated that the operations of RU 220 may be performed by O-RU 253-1. The description of RU 220 may be applied to O-DU 253-1.

[0055] Figure 3a A functional configuration of a distributed unit (DU) according to an embodiment is shown. Figure 3a The configuration shown in can be understood as Figure 2a DU 210 (or Figure 2b The configuration of the O-DU 250) is a part of the base station. Hereinafter, as used herein, the terms "unit", "processor / processor" and the like refer to a unit that processes at least one function or operation, which can be implemented by hardware or software, or a combination of hardware and software.

[0056] Reference Figure 3a , the DU 210 includes a transceiver 310 , a memory 320 , and a processor 330 .

[0057] The transceiver 310 may perform functions for sending and receiving signals in a wired communication environment. The transceiver 310 may include a wired interface for controlling a direct connection between a device and another device through a transmission medium (e.g., copper wire, optical fiber). For example, the transceiver 310 may send an electrical signal to another device through a copper wire or perform conversion between an electrical signal and an optical signal. The DU 210 may communicate with a radio frequency unit (RU) through the transceiver 310. The DU 210 may be connected to a core network or a CU in a distributed deployment via the transceiver 310.

[0058] The transceiver 310 may also perform functions for sending and receiving signals in a wireless communication environment. For example, the transceiver 310 may perform a conversion function between a baseband signal and a bit stream according to the physical layer standard of the system. For example, once data is sent, the transceiver 310 generates complex symbols by encoding and modulating the transmission bit stream. In addition, once data is received, the transceiver 310 recovers the received bit stream by demodulating and decoding the baseband signal. In addition, the transceiver 310 may include multiple transmit / receive paths. In addition, according to an embodiment, the transceiver 310 may be connected to a core network or other nodes (e.g., an integrated access backhaul (IAB)).

[0059] The transceiver 310 may send and receive signals. For example, the transceiver 310 may send a management plane (M-plane) message. For example, the transceiver 310 may send a synchronization plane (S-plane) message. For example, the transceiver 310 may send a control plane (C-plane) message. For example, the transceiver 310 may send a user plane (U-plane) message. For example, the transceiver 310 may receive a user plane message. Figure 3a Only the transceiver 310 is shown in FIG. 2 , but according to another embodiment, the DU 210 may include two or more transceivers.

[0060] As described above, the transceiver 310 transmits and receives signals. Therefore, all or part of the transceiver 310 may be referred to as a "communication unit", "transmission unit", "reception unit", or "transmission / reception unit". In addition, in the following description, transmission and reception performed via a wireless channel are used as meanings including the processing performed by the transceiver 310 as described above.

[0061] although Figure 3a Although not shown in the figure, the transceiver 310 may also include a backhaul transceiver connected to the core network or another base station. The backhaul transceiver provides an interface for performing communication with other nodes in the network. That is, the backhaul transceiver may convert a bit stream sent from the base station to another node (e.g., another access node, another base station, an upper node, a core network, etc.) into a physical signal, and may convert a physical signal received from another node into a bit stream.

[0062] The memory 320 stores data such as, for example, basic programs, application programs, setting information, etc., used for the operation of the DU 210. The memory 320 may be referred to as a storage unit. The memory 320 may include a volatile memory, a nonvolatile memory, or a combination of a volatile memory and a nonvolatile memory. In addition, the memory 320 provides stored data according to a request of the processor 330.

[0063] The processor 330 may control the overall operation of the DU 210. The processor 380 may be referred to as a controller. For example, the processor 330 transmits and receives signals through the transceiver 310 (or through a backhaul communication unit). In addition, the processor 330 records data in the memory 320 and reads data from the memory 320. In addition, the processor 330 may perform the functions of the protocol stack required by the communication standard. Although in Figure 3a Only processor 330 is shown in FIG. 2 , but according to other implementations, DU 210 may include two or more processors.

[0064] Figure 3a The configuration of the DU 210 shown is only an example, and examples of DUs that implement embodiments of the present disclosure are not limited to Figure 3a In some embodiments, some configurations may be added, deleted or modified.

[0065] Figure 3b A functional configuration of a radio frequency unit (RU) according to an embodiment is shown. Figure 3b The configuration shown can be understood as a part of a base station. Figure 2b RU 220 or Figure 2b Hereinafter, the terms "unit", "processor / device" and the like refer to a unit that processes at least one function or operation, which may be implemented by hardware or software or a combination of hardware and software.

[0066] Reference Figure 3b , RU 220 includes an RF transceiver 360 , a fronthaul transceiver 365 , a memory 370 , and a processor 380 .

[0067] The RF transceiver 360 performs functions for transmitting and receiving signals via a wireless channel. For example, the RF transceiver 360 may up-convert a baseband signal into an RF band signal, and then transmit the baseband signal through an antenna, and down-convert the RF band signal received through the antenna into a baseband signal. For example, the RF transceiver 360 may include a transmit filter, a receive filter, an amplifier, a mixer, an oscillator, a DAC, an ADC, and the like.

[0068] The RF transceiver 360 may include multiple transmit / receive paths. In addition, the RF transceiver 360 may include an antenna unit. The RF transceiver 360 may include at least one antenna array having multiple antenna elements. In terms of hardware, the RF transceiver 360 may include digital circuits and analog circuits (e.g., radio frequency integrated circuits (RFIC)). Here, the digital circuits and the analog circuits may be implemented as a single package. In addition, the RF transceiver 360 may include multiple RF chains. The RF transceiver 360 may perform beamforming. The RF transceiver 360 may apply beamforming weights to signals to be transmitted / received so as to present directivity according to the settings of the signals by the processor 380. According to an embodiment, the RF transceiver 360 may include a radio frequency block (or RF unit).

[0069] According to an embodiment, the RF transceiver 360 may send and receive signals through a wireless access network. For example, the RF transceiver 360 may send a downlink signal. The downlink signal may include a synchronization signal (SS), a reference signal (RS) (e.g., a cell-specific reference signal (CRS), a demodulation (DM)-RS), system information (e.g., MIB, SIB, remaining system information (RMSI), other system information (OSI)), a configuration message, control information, downlink data, etc. For example, the RF transceiver 360 may receive an uplink signal. The uplink signal may include a random access-related signal (e.g., a random access preamble (RAP) (or Msg1 (message 1), Msg3 (message 3)), a reference signal (e.g., a sounding reference signal (SRS), DM-RS), or a power headroom report (PHR), etc. Although in Figure 3b Only the RF transceiver 360 is shown in FIG. 2 , but according to another example of implementation, the RU 220 may include two or more RF transceivers.

[0070] The fronthaul transceiver 365 may send and receive signals. According to an embodiment, the fronthaul transceiver 365 may send and receive signals on the fronthaul interface. For example, the fronthaul transceiver 365 may receive a management plane (M-plane) message. For example, the fronthaul transceiver 365 may receive a synchronization plane (S-plane) message. For example, the fronthaul transceiver 365 may receive a control plane (C-plane) message. For example, the fronthaul transceiver 365 may send a user plane (U-plane) message. For example, the fronthaul transceiver 365 may receive a user plane message. Although in Figure 3b Only the fronthaul transceiver 365 is shown in FIG. 2 , but according to another example of implementation, the RU 220 may include two or more fronthaul transceivers.

[0071] As described above, the RF transceiver 360 and the fronthaul transceiver 365 transmit and receive signals. Therefore, all or part of the RF transceiver 360 and the fronthaul transceiver 365 may be referred to as a "communication unit", "transmission unit", "reception unit" or "transmission / reception unit". In addition, in the following description, transmission and reception performed through a wireless channel may be used as a meaning including the processing performed by the RF transceiver 360 as described above. In the following description, transmission and reception performed through a wireless channel may be used as a meaning including the processing performed by the RF transceiver 360 as described above.

[0072] The memory 370 stores data such as basic programs, application programs, and setting information for the operation of the RU 220. The memory 370 may be referred to as a storage unit. The memory 370 may include a volatile memory, a nonvolatile memory, or a combination of a volatile memory and a nonvolatile memory. In addition, the memory 370 provides the stored data according to a request from the processor 380. According to an embodiment, the memory 370 may include a memory for conditions, instructions, or setting values ​​related to the SRS transmission scheme.

[0073] The processor 380 controls the overall operation of the RU 220. The processor 380 may be referred to as a controller. For example, the processor 380 sends and receives signals through the RF transceiver 360 or the fronthaul transceiver 365. In addition, the processor 380 records data in the memory 370 and reads data from the memory 370. In addition, the processor 380 may perform the functions of the protocol stack required by the communication standard. Although in Figure 3bOnly the processor 380 is shown in the figure, but according to another example of implementation, the RU 220 may include two or more processors. The processor 380 may be a storage device for storing therein instructions or codes at least temporarily residing in the processor 380 as an instruction set or code stored in the memory 370, or may be a part of the circuit configuring the processor 380. In addition, the processor 380 may include various modules for performing communication. The processor 380 may control the RU 220 to perform operations according to the embodiments to be described below.

[0074] Figure 3b The configuration of RU 220 shown is only an example and is not intended to be construed as Figure 3b The examples of RUs configured to perform embodiments of the present disclosure are not limited thereto. In some embodiments, some configurations may be added, deleted, or changed.

[0075] Figure 4 An example of functional splitting between DU and RU according to an embodiment is shown. With the further development of wireless communication technology (for example, the introduction of 5G communication systems (or new radio (NR) communication systems)), the frequency bands in use have further increased. As the cell radius of the base station becomes very small, the number of RUs that need to be installed further increases. In addition, in the 5G communication system, the amount of data transmitted has greatly increased by 10 times or more, significantly increasing the transmission capacity of the wired network transmitted to the fronthaul. Due to the above factors, the installation cost of the wired network in the 5G communication system can be greatly increased. Therefore, in order to reduce the transmission capacity of the wired network and reduce the installation cost of the wired network, this "functional split" can be used to reduce the transmission capacity of the fronthaul by transferring some functions of the modem in the DU to the RU.

[0076] To reduce the burden on the DU, the role of the RU, which is only responsible for traditional RF functions, can be extended to some functions of the physical layer. As the RU performs higher-layer functions, the throughput of the RU increases, so that the transmission bandwidth in the fronthaul can be increased, while the constraints on latency requirements are reduced due to response processing. At the same time, as the RU performs higher-layer functions, the virtualization gain decreases, and the size, weight, and cost of the RU may increase. Considering the trade-offs of the above advantages and disadvantages, it is necessary to achieve optimal functional segmentation.

[0077] Reference Figure 4, showing the functional division in the physical layer below the MAC layer. In the case of downlink (DL) sending 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, RF conversion, etc. In the case of uplink (UL) receiving 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, decoding / descrambling, etc. The separation of uplink functions and downlink functions can be defined in various types according to the above-mentioned tradeoffs by necessity between vendors, discussions in the specification, etc.

[0078] In the first functional partition 405, the RU performs the RF function and the DU performs the PHY function. The first functional partition in which the PHY function in the RU is not substantially implemented can be referred to as, for example, option 8. In the second functional partition 410, the RU performs iFFT conversion / CP addition in the DL of the PHY function and performs FFT conversion / CP removal in the UL, and the DU performs the remaining PHY functions. For example, the second functional partition 410 can be referred to as option 7-1. In the third functional partition 420a, the RU performs iFFT conversion / CP addition in the DL of the PHY function and performs FFT conversion / CP removal and digital beamforming in the UL, and the DU performs the remaining PHY functions. For example, the third functional partition 420a can be referred to as option 7-2x category A. In the fourth functional partition 420b, the RU performs digital beamforming in both DL and UL, and the DU performs upper layer PHY functions after digital beamforming. For example, the fourth functional partition 420b can be referred to as option 7-2x category B. In the fifth functional partition 425, the RU performs RE mapping (or RE demapping) in both DL and UL, and the DU performs upper layer PHY functions after RE mapping (or RE demapping). For example, the fifth functional partition 425 can be referred to as option 7-2. In the sixth functional partition 430, the RU performs modulation (or demodulation) in both DL and UL, and the DU performs higher layer PHY functions after modulation (or demodulation). For example, the sixth functional partition 430 can be referred to as option 7-3. In the seventh functional partition 440, the RU performs encoding / scrambling (or decoding / descrambling) in both DL and UL, and the DU performs higher layer PHY functions after modulation (or demodulation). As an example, the seventh functional partition 440 can be referred to as option 6.

[0079] According to an embodiment, when a large amount of signal processing is expected (such as FR 1 MMU), functional partitioning at a relatively high level (e.g., the fourth functional partitioning 420b) may be required to reduce the fronthaul capacity. In addition, functional partitioning at an excessively high level (e.g., the sixth functional partitioning 430) may complicate the control interface and include multiple PHY processing blocks within the RU, which may impose a significant burden on the implementation of the RU, and therefore, depending on the deployment and implementation scheme of the DU and the RU, appropriate functional partitioning may be required.

[0080] According to an embodiment, when it is impossible to process precoding of data received from the DU (i.e., when there is a limitation on the precoding capability of the RU), the third functional partition 420a or a lower-level functional partition thereof (e.g., the second functional partition 410) may be applied. Conversely, when there is a capability to process precoding of data received from the DU, the fourth functional partition 420b or a higher-level functional partition thereof (e.g., the sixth functional partition 430) may be applied.

[0081] Hereinafter, unless otherwise specified, embodiments of the present disclosure are described based on the third functional partition 420a (which may be referred to as "category A, CAT-A") or the fourth functional partition 420b (which may be referred to as "category B, CAT-B") for performing beamforming in the RU. In the O-RAN standard, the type of O-RU is distinguished according to whether the precoding function is located at the interface of the O-DU or at the interface of the O-RU. An O-RU in which precoding is not performed (i.e., with low complexity) may be referred to as a CAT-AO-RU. An O-RU in which precoding is performed may be referred to as a CAT-B O-RU.

[0082] Hereinafter, upper PHY refers to physical layer processing processed in the DU of the fronthaul interface. For example, the upper PHY may include FEC encoding / decoding, scrambling, and modulation / demodulation. Hereinafter, lower PHY refers to physical layer processing processed in the RU of the fronthaul interface. For example, the lower PHY may include FFT / iFFT, digital beamforming, and physical random access channel (PRACH) extraction and filtering. However, the above standards are not intended to exclude embodiments by other functional partitioning. The following description will be Figures 5 to 10 The functional configuration, signaling, or operation may be applied not only to the third functional partition 420a or the fourth functional partition 420b but also to other functional partitions.

[0083] Embodiments of the present disclosure describe when a DU (e.g., Figure 2a DU 210) and RU (e.g., Figure 2aWhen sending messages between RU 220 of the present invention, eCPRI and O-RAN are examples of specifications of the fronthaul interface. The Ethernet payload of the message may include an eCPRI header, an O-RAN header, and additional fields. In the following, standard terms of eCPRI or O-RAN are used to describe various embodiments of the present disclosure, but other expressions having the same meaning as the corresponding terms may be used to replace the various embodiments of the present disclosure.

[0084] As the transmission protocol for fronthaul, Ethernet and eCPRI, which are easy to share with the network, can be used. The eCPRI header and O-RAN header can be included in the Ethernet payload. The eCPRI header can be located before the Ethernet payload. The content of the eCPRI header is as follows.

[0085] 1) ecpriVersion (4 bits): This parameter indicates the eCPRI protocol version.

[0086] 2) ecpriReserved (3 bits): This parameter is reserved for further use of eCPRI.

[0087] 3) ecpriConcatenation (1 bit): This parameter indicates when eCPRI concatenation is used.

[0088] 4) ecpriMessage (1 byte): This parameter indicates the type of service carried by the message type. For example, the parameter indicates an IQ data message, a real-time control data message, or a transport network delay measurement message.

[0089] 5) ecpriPayload (2 bytes): This parameter indicates the byte size of the payload portion of the eCPRI message.

[0090] 6) ecpriRtcid / ecpriPcid (2 bytes): This parameter is the eAxC (Extended Antenna Carrier) Identifier (eAxCID) and identifies the specific data stream associated with each C-Plane (ecpriRtcid) or U-Plane (ecpriPcid) message.

[0091] 7) ecpriSeqid (2 bytes): This parameter provides unique message identification and order at two levels. The first octet of this parameter is the sequence ID used to identify the order of messages within the eAxC message stream, and the sequence ID is used to identify that all messages have been received and to realign out-of-order messages. The second octet of this parameter is the subsequence ID. When radio transmission level segmentation (eCPRI or IEEE-1914.3) occurs, the subsequence ID is used to identify the order and enable reordering.

[0092] The eAxC identifier (ID) includes a band and sector identifier ("BandSector_ID"), a component carrier identifier ("CC_ID"), a spatial stream identifier ("RU_Port_ID"), and a distributed unit identifier ("DU_Port_ID"). The bit allocation of the eAxC ID can be classified as follows.

[0093] 1) DU_port ID: DU_port ID is used to distinguish processing units in O-DU (e.g., other baseband cards). It is expected that O-DU allocates bits for DU_port ID and O-RU appends the same value to UL U-Plan message carrying the same sectionId data.

[0094] 2) BandSector_ID: Aggregate cell identifier (separates the frequency bands and sectors supported by the O-RU).

[0095] 3) CC_ID: CC_ID distinguishes the carrier component supported by the O-RU.

[0096] 4) RU_port ID: The RU_port ID specifies logical flows such as data layers or spatial streams, and logical flows such as signal channels that require special antenna allocations such as separate parameter sets (e.g., PRACH) or SRS.

[0097] The fronthaul application protocol may include the control plane (C-plane), the user plane (U-plane), the synchronization plane (S-plane) and the management plane (M-plane).

[0098] The control plane can be configured to provide scheduling information and beamforming information through control messages. The control plane refers to real-time control between the DU and the RU. The user plane may include IQ sampling data transmitted between the DU and the RU. The user plane may include the user's downlink data (IQ data or synchronization signal block (SSB) / reference signal (RS)), uplink data (IQ data or SRS / RS) or physical random access channel (PRACH) data. The weight vector of the above beamforming information can be multiplied by the user data. The synchronization plane generally refers to the service between the DU and the RU for the synchronization controller (e.g., IEEE Advanced Master Device). The synchronization plane may be related to timing and synchronization. The management plane refers to non-real-time control between the DU and the RU. The management plane may be related to initial setup, non-real-time reset or reset, and non-real-time reporting.

[0099] The control plane message, i.e., the C-plane message, can be encapsulated based on a two-layer header method scheme. The first layer can consist of an eCPRI common header or an IEEE 1914.3 common header including a field for indicating the message type. The second layer is an application layer including fields necessary for control and synchronization. In the application layer, a segment defines the characteristics of the U-plane data transmitted or received in a beam with one pattern ID. The segment types supported in the C-plane are as follows.

[0100] The section type may indicate the use of a control message sent in the control plane. For example, the use of each section type is as follows.

[0101] 1) Segment type = 0: used to indicate resource blocks or symbols that are not used in DL or UL.

[0102] 2) Segment type = 1: used for most DL / UL radio channels. Here, the term "most" refers to channels that do not require time or frequency offset, such as required for hybrid parameter set channels.

[0103] 3) Segment Type = 2: Reserved for further use.

[0104] 4) Segment type = 3: PRACH and mixed parameter set channels, which require time or frequency offset or are different from the nominal SCS value.

[0105] 5) Segment Type = 4: Reserved for further use.

[0106] 6) Segment type = 5: UE scheduling information, sending UE scheduling information to enable RU to perform real-time BF weight calculation (O-RAN optional BF solution).

[0107] 7) Segment type = 6: UE-specific channel information transmission, UE channel information is sent regularly so that RU can perform real-time BF weight calculation (O-RAN optional BF solution).

[0108] 8) Segment type = 7: used for LAA support.

[0109] 9) Segment type = 8: used for ACK / NACK feedback.

[0110] In 5G NR, PRBs in which each PRB includes the same number of subcarriers are defined for all parameter sets. A PRB may include 12 subcarriers. A parameter set refers to a subcarrier spacing (SCS) and a symbol length in an orthogonal frequency division multiplexing (OFDM) system. Since the SCS may be different for each parameter set, a hybrid parameter set may be used in the time domain and the frequency domain, respectively. For example, a hybrid parameter set may be used for URLLC transmission. In addition, for example, when the parameter sets of data in FR 2 (or FR 2-1 or FR 2-2), such as the parameter sets of the physical downlink shared channel (PDSCH) and the synchronization signal block (SSB), are different, a hybrid parameter set may be used.

[0111] Figure 5 The difference in grid units between ARFCN (Absolute Radio Frequency Channel Number) and GSCN (Global Synchronization Channel Number) according to an embodiment is shown.

[0112] Reference Figure 5 , the frequency domain 500 may include candidates 510 for bandwidth center frequencies according to a channel grid. Each candidate for bandwidth center frequencies may be numbered based on the ARFCN. The frequency domain 5300 may include candidates 520 for SSB center frequencies according to a synchronization grid. Each candidate for SSB center frequencies may be numbered based on the GSCN.

[0113] Global frequency grid definition F REF , which is a set of RF reference frequencies. The RF reference frequencies can be used to identify the location of RF channels, SSBs, and other elements in the signal. A global frequency grid is defined for all frequencies in the range of 0 to 100 GHz. The granularity of the global frequency grid is The RF reference frequency may be specified based on the NR absolute radio frequency channel number (NR-ARFCN). For example, NREF corresponding to the NR-ARFCN and F corresponding to the RF reference frequency REF The relationship between is shown in the following equation and table.

[0114] <Equation 1>

[0115]

[0116] The synchronization grid may indicate the frequency position of the SSB. When there is no explicit signaling of the synchronization block position, it indicates the frequency position of the SSB that can be used by the UE for system acquisition. A global synchronization grid is defined for all frequencies. The frequency position of the SSB together with the corresponding digital GSCN is defined as the SSB. REFFor example, the positions of the candidates 520 of the synchronization signal (eg, SSB) according to the frequency range may be defined as shown in the following table.

[0117]

[0118] A standalone (SA) system is a system that operates the control plane (C-plane) and the user plane (U-plane) in the same RAN node. The center frequency used to transmit the SSB corresponding to the C-plane refers to the SS REF , but the center frequency of the system bandwidth (or bandwidth portion) corresponding to the user plane is F REF As mentioned above, SS REF is the unit of GSCN, and F REF are different units of the ARFCN.

[0119] In the FR 2 band, the unit of ARFCN is 60kHz, while the unit of GSCN is 17.28 MHz, so when the center frequency between the two channels is different, a frequency offset may occur between the two physical channels. For example, the frequency band of FR 2 may be the n257 band (26.50 GHz to 29.50 GHz), the n258 band (24.25 GHz to 27.50 GHz), the n260 band (37.00GHz to 40.00 GHz), or the n261 band (27.25 GHz to 28.35 GHz). In the frequency band of FR 2, SSB transmission may use a parameter set of 240 kHz. At the same time, the maximum SCS of data transmission within the frequency band of FR 2 is 120 kHz. However, the above-mentioned grid difference and SCS difference require more detailed units of frequency offset correction. The frequency compensation value can be expressed by the following equation.

[0120] <Equation 2>

[0121] in, SCS representing SSB, SS for SSB REF ,and Indicates F REF , which is the center frequency of the channel bandwidth. For example, in the n257 band, the frequency offset per GSCN according to the search for SSB with an SCS of 240 kHz can be expressed as follows.

[0122]

[0123] Figure 6An example of offset compensation for a synchronization signal block (SSB) having a center frequency different from the center frequency of the system bandwidth according to an embodiment is shown.

[0124] Reference Figure 6 , a model is assumed in which the center frequency of the system bandwidth 653 (hereinafter, referred to as the bandwidth center frequency 651) and the center frequency of the SSB (hereinafter, referred to as the SSB center frequency 655) are different. The bandwidth center frequency 651 is f 0 , and the SSB center frequency 655 is f ssb The difference between the two center frequencies is 657 d (Frequency difference)(=f sb -f 0 ).

[0125] Difference "f d " can include SCS based on SSB ( ) multiple part and fractional part. The multiple part refers to the part of the SCS of the SSB that is an integer multiple of the center frequency difference. The fractional part can be a part of the SCS of the SSB in the center frequency difference. That is, the fractional part can be the product of the SCS of the SSB and a fraction less than 1 (or a fraction with a magnitude less than 1). The multiple part can be expressed as ( ), and the decimal part can be represented by ( or )express. can be defined as having According to the 3GPP standard (eg, Section 5.4 of 3GPP TS 38.211), a bandwidth center frequency 651 is used for uplink conversion of SSB, and thus the time domain of SSB can be developed by the following equation.

[0126] <Equation 3>

[0127] <Equation 4>

[0128] <Equation 5>

[0129] here, Represents the SSB signal converted from the frequency domain to the time domain. Indicates l The cyclic prefix (CP) length of the symbol. Indicates the inverse fast forward transform (IFFT) size. Indicates the sampling rate (in seconds). Indicates that the frequency is shifted by RE offset The SSB signal in the time domain. That is, .

[0130] Referring to Equation 5, if the component of the system bandwidth ( ) and the frequency conversion component ( ) is the frequency relative to the center frequency of the system bandwidth ( ) is shifted by the correction value ( ). The frequency shift component identified from the frequency offset ( ) can also be corrected in the time domain. Depending on the functional partitioning of the O-RAN (eg, the third functional partitioning 420a or the fourth functional partitioning 420b), the correction in the time domain can be performed in the RU.

[0131] For correction in RU, O-RAN standard provides frequency offset (freqOffset) field in segment type "3" and segment extension type "15". DU can provide frequency offset value to RU through C-plane message. Here, freqOffset field can be defined as follows.

[0132] <Equation 6>

[0133] Here, "Δf" refers to the SCS provided in the frame structure. "freqOffset" is the value of the freqOffset field of the C-plane message. The value of the freqOffset field of the C-plane message expresses the frequency offset value as the number of counting units by considering a part of the SCS as a counting unit. In the following, the ratio indicating a part of the SCS may be referred to as a frequency offset factor (or fractional frequency offset). As an example, in Equation 6, the frequency offset factor is 0.5. The product of the frequency offset factor and the SCS may be referred to in units of offset. For example, for an SSB with an SCS of 240 kHz, the DU may recognize an offset unit of 120 kHz to the RU. However, since the ARFCN is a unit of 60 kHz, it is difficult for an offset unit of 120 kHz to indicate a sufficient frequency offset. For example, looking back at Table 3 above, by the separation of GSCN and ARFCN and the S REF and F REF The resolution difference between the two is 0.25 units. size.

[0134] In FR 2 (or FR 2-1), the channel grid of ARFCN is 60 kHz, but since the parameter set of SCS is 240 kHz, frequency compensation in units of 60 / 240 = (1 / 4) is required. In addition, considering the FR 2-2 band introduced in Release 17, in a band supporting SCS of 480 kHz and SCS of 960 kHz, frequency compensation requires an offset unit more detailed than "0.5" of Equation 6 (e.g., 0.25, 0.125).

[0135] In an embodiment of the present disclosure, a method for providing all possible frequency compensation values ​​to RU through the O-RAN standard by analyzing the occurrence range of the frequency compensation value is proposed. In particular, in a FR2 SA (standalone) system, when the center frequency between the SSB and the system bandwidth is different, as an example case, the frequency offset compensation of the unit requiring more detailed support will be described.

[0136] Figure 7 An example 700 of a control plane (C-plane) message according to an embodiment is shown. Figure 7 , "sectionType=3" for a hybrid parameter set channel is shown. However, the section type indicating "3" is only an example, and another section type may be used to provide a frequency offset (eg, "freqOffset" in the ORAN standard).

[0137] Reference Figure 7 , the C-plane message may include a transport header (e.g., an eCPRI header or IEEE 1914.3 information). As described above, the transport header may include "ecpriVersion", "ecpriReserved", "ecpriConcatenation", "ecpriMessage", "ecpriPayload", "ecpriRtcid / ecpriPcid", and "ecpriSeqid".

[0138] The C-plane message may include common header information. The common header information may include a "data direction" indicating a data transmission direction of a base station (e.g., gNB), a "payload version" indicating a payload protocol version of an IE in an application layer, and a "filter index" indicating an index of a channel filter between IQ data and an air interface to be used in both DL and UL.

[0139] The common header information may include information for indicating the location of the time resource to which the message applies. The location of the time resource may be indicated by a frame, a subframe, a time slot, or a symbol. The common header information may include a "frameId" indicating a frame number, a "subframeId" indicating a subframe number, a "slotId" indicating a time slot number, and a "startSymbolId" indicating a symbol number. The frame is determined based on a 256 modulo operation. A subframe consists of 1ms units included in a 10ms frame. The time slot number is numbered within a subframe, and its maximum size may be 1, 2, 4, 8, or 16 depending on the parameter set.

[0140] The common header information may include a "numberOfsection" indicating the number of data sections included in the C-plane message. The common header information may include a "sectionType" that determines the characteristics of the U-plane data. The common header information may include a "timeoffset" that defines the start of the time slot to the start of the cyclic prefix (CP) with the number of samples (e.g., Ts=1 / 30.72 MHz). The common header information may include a "frameStructure" that defines the Fast Fourier Transform (FFT) / iFFT (inverse FFT) size and the SCS. The common header information may include a "cpLength" that defines the CP length with the number of samples (e.g., Ts=1 / 30.72 MHz).

[0141] "frameStructure" included in the common header information defines the frame structure. "frameStructure" may indicate the FFT / iFFT size and SCS. For example, for the frame structure, the following table may be referred to.

[0142]

[0143] The first part of "frameStructure" (e.g., the most significant bits (MSB) 4 bits) may indicate a parameter of "FFT size". The "FFT size" parameter defines the FFT / iFFT size used to process all IQ data related to the C-plane message. The second part of "frameStructure" (e.g., the least significant bits (LSB) 4 bits) may indicate a "μ" parameter. Considering the LTE standard (e.g., TS 36.211) and the NR standard (e.g., TS 38.211), the "μ" parameter defines the number of time slots per 1 ms (millisecond) subframe and SCS. At the same time, the "FFT size" parameter provided is for the convenience of calculation, rather than strictly indicating the time-frequency conversion method of the RU.

[0144] For the "FFT Size" parameter, refer to the table below.

[0145]

[0146] For the "μ" parameter, please refer to the table below.

[0147]

[0148] In the above table, for NR PRACH, 1.25 kHz and 5 kHz can be supported. For Narrowband (Nb)-IoT (Internet of Things) PRACH, 3.75 kHz can be supported. For LTE PRACH, 15 kHz, 7.5 kHz and 1.25 kHz can be supported. For LTE PRACH, 1.25 kHz and 7.5 kHz can be supported.

[0149] The C-plane message may include segment information. The segment information may include a "sectionId" indicating a segment identifier. When using the C-plane and U-plane coupled by "sectionId", "sectionId" identifies a single data segment described by the data segment description in the C-plane message. The purpose of "sectionId" is to map the U-plane data segment to the corresponding C-plane message (and segment type) associated with the data. The segment information may include "rb" indicating whether all RBs are used (use each RB) or whether all other RBs are used (each other RB), "symInc" indicating a symbol number increment command, "startPrbc" indicating the number of starting PRBs described in the data segment, "numPrbc" indicating the number of consecutive PRBs described in each data segment, "reMask" defining the RE mask in the PRB, "numSymbol" defining the number of repetitions or symbols of the physical random access channel (PRACH) to which segment control is applied, "ef" indicating an extension flag, and "beamId" defining the beam pattern to be applied to the U-plane data. The segment information may include frequency offset information that defines a frequency offset of a carrier center frequency in a specific unit (hereinafter referred to as an offset unit), namely, "freqOffset". The offset unit corresponds to the product of the SCS and a fractional value. Here, the fractional value may be referred to as a frequency offset factor. The frequency span due to "frameStructure", "freqOffset", "startPrbc", "numPrbc", and "rb" of the C-plane message does not exceed the channel bandwidth configured for the eAxC of the M-plane.

[0150] The value indicated by the bit of the frequency offset information defines the frequency offset used for the carrier center frequency in units of offset before additional filtering (e.g., in the case of PRACH) and FFT processing (in the case of UL). The frequency offset should be consistent for each data segment (the segment cannot use reMask to allow different frequency offsets for different REs of a PRB).

[0151] In some embodiments, the frequency offset information included in the C-plane message can be used to identify the frequency offset value based on the M-plane message. The M-plane message can indicate the frequency offset factor. The M-plane message can include information for indicating the frequency offset factor. For example, the frequency offset factor provided by the M-plane message can be 0.5. In addition, for example, the frequency offset factor provided by the M-plane message can be 0.25. In addition, for example, the frequency offset factor provided by the M-plane message can be 0.125.

[0152] According to an embodiment, the frequency offset value may be determined based on the following equation.

[0153] <Equation 7>

[0154] "frequency_offset" indicates the frequency offset value to be applied. "Δf" indicates the SCS provided by the frame structure information of the C-plane message. "freqOffset" represents the value of the bit of the frequency offset information received from the C-plane message. "fractFreqMode" indicates information for indicating the frequency offset factor included in the M-plane message. Here, the DU can send information for indicating the frequency offset factor to the RU through the optional multi-vendor function of the O-RAN standard in the M-plane. For example, the "fractFreqMode" information can be added as an "optimal multi-vendor" item.

[0155] As an example, the frequency offset information may be composed of 24 bits. These 24 bits indicate a signed integer. When the 24 bits indicate 0, it may indicate that there is no offset; when the value of the 24 bits is in the range of 0x000001 to 0x7FFFFF (0x represents a hexadecimal number, and F represents 15), the frequency offset information may indicate a positive frequency offset; and when the value of the 24 bits is in the range of 0x800000 to 0xFFFFFF, the frequency offset information may indicate a negative frequency offset.

[0156] In some other embodiments, the frequency offset information included in the C-plane message may be used to identify the frequency offset value based on the frame structure information included in the C-plane message. The frame structure information included in the C-plane message may include FFT information for indicating the FFT / iFFT size for IQ data processing and parameter set information for indicating the SCS. As described above, Table 4 may be used for frame structure information. Table 5 may be used for FFT information. However, unlike Table 6, the parameter set information may indicate the frequency offset factor as well as the SCS. For example, according to an embodiment, the following table may be used for parameter set information.

[0157]

[0158] When the value of the bit of the parameter set information is 2, the SCS may be 60 kHz, and the frequency factor may be 0.5. However, when the value of the bit of the parameter set information is 7 (=0111b), the SCS may be 60 kHz, and the frequency factor may be 0.25. In addition, for example, when the value of the bit of the parameter set information is 3, the SCS may be 120 kHz, and the frequency factor may be 0.5. However, when the value of the bit of the parameter set information is 8 (=1000b), the SCS may be 120 kHz, and the frequency factor may be 0.25. In addition, for example, when the value of the bit of the parameter set information is 4, the SCS may be 240 kHz, and the frequency factor may be 0.5. However, when the value of the bit of the parameter set information is 9 (=1001b), the SCS may be 240 kHz, and the frequency factor may be 0.25. In addition, for example, when the value of the bit of the parameter set information is 5, the SCS may be 480 kHz, and the frequency factor may be 0.5. However, when the value of the bit of the parameter set information is 10 (=1010b), the SCS may be 480kHz and the frequency factor may be 0.25. In addition, for example, when the value of the bit of the parameter set information is 6, the SCS may be 960kHz and the frequency factor may be 0.5. However, when the value of the bit of the parameter set information is 11 (=1011b), the SCS may be 960kHz and the frequency factor may be 0.25. The value of the bit of the parameter set information may indicate the frequency factor. Table 7 above may be represented by the following equation.

[0159] <Equation 8>

[0160] "frameStructure[4:7]" indicates the LSB 4-bits of the frame structure information, and also indicates a bit for indicating the SCS. "frequency_offset" indicates a frequency offset value to be applied. "Δf" indicates the SCS provided by the frame structure information of the C-plane message. "freqOffset" indicates the value of a bit of the frequency offset information received from the C-plane message.

[0161] As an example, the frequency offset information may include 24 bits. The 24 bits indicate a coded integer. When the 24 bits indicate 0, it indicates no offset, and when the value of the 24 bits is in the range of 0x000001 to 0x7FFFFF, the frequency offset information may indicate a positive frequency offset, and when the value of the 24 bits is in the range of 0x800000 to 0xFFFFFF, the frequency offset information may indicate a negative frequency offset.

[0162] Table 7 above is merely an example of frame structure information for defining an additional offset factor and is not intended to be interpreted as limiting the embodiments. As shown in Table 7, not all of the reserved bits in Table 4 are used to indicate additional SCS (480 kHz, 960 kHz) and frequency offset factors, but only some of the reserved bits in Table 4 can be used to indicate frequency offset factors. For example, the value of the bit used to indicate the SCS can provide various frequency offset factors (e.g., 0.5, 0.25) only for situations where an additional frequency offset factor (e.g., 240 kHz, 480 kHz, 960 kHz) is required.

[0163]

[0164] As another example, the value of the bit indicating the SCS may provide various frequency offset factors (eg, 0.5, 0.25, 0.125) only for cases where an additional frequency offset factor (eg, 240 kHz, 480 kHz, 960 kHz) is required.

[0165]

[0166] When the SCS bit indicates 10, the SCS may be 240 kHz and the frequency shift factor may be 0.125. When the SCS bit indicates 11, the SCS may be 480 kHz and the frequency shift factor may be 0.125.

[0167] In Tables 7 to 9 above, the range of field values ​​for the bits indicating the SCC (e.g., frameStructure[4:7]) indicates the frequency offset factor. In Tables 7 to 9, the field values ​​indicate the frequency offset factor regardless of the value of the SCS. However, the range of possible frequency offset factors may depend on the SCS. In other words, the candidate values ​​of the required frequency offset factor may vary depending on which SCS is used. For example, when the SCS is 120 kHz, only a frequency offset factor of 0.5 may be used. As another example, when the SCS is 480 kHz, frequency offset factors with values ​​of 0.5, 0.25, and 0.125 may be used. For example, the field value may indicate the SCS and the frequency offset factor according to the following table and equation.

[0168]

[0169] <Equation 9>

[0170] According to an additional embodiment, the frequency offset factor indicated by the field value of the bit used to indicate the SCS may be associated with the SCS provided by the field value. The frequency offset factor used may be fixed according to the provided SCS. For example, when the field value of the bit used to indicate the SCS indicates an SCS of 240 kHz, the frequency offset may be 0.5 and 0.25. For another example, when the field value of the bit used to indicate the SCS indicates an SCS of 480 kHz, the frequency offset may be 0.25 and 0.125. For another example, when the field value of the bit used to indicate the SCS indicates an SCS of 960 kHz, the frequency offset may be 0.125 and 0.0625.

[0171] Within the same technical scope, some elements in Tables 7 to 10 may be omitted, or other mapping columns may be added.

[0172] exist Figure 7 In the embodiment, the frequency offset information included in the segment information of the C-plane message is described as an example, but the frequency offset information can be included not only in the segment information but also in the segment extension information. Figure 8 In the description, segment extension information including frequency offset information will be described.

[0173] Figure 8 An example 800 of segment extension information according to an embodiment is shown. Figure 8, segment extension information for hybrid parameter set information is shown. The C-plane message may include segment information and segment extension information. Here, the segment type of the segment information may be "5" or "6". The C-plane message may be used for UE scheduling information (segment type = 5), or may be used for sending UE specific channel information (segment type = 6).

[0174] Reference Figure 8 , the section extension information may include "extType" providing the extension type, which provides additional parameters. The section extension information may include "ef" to indicate whether there is another extension or whether the current extension field is the last extension. The section extension information may include "extLen" which provides the length of the section extension in 32-bit (or 4-byte) words.

[0175] The segment extension information may include a "frameStructure" for indicating a frame structure (e.g., Figure 7 The segment extension information may include "cpLength". "cpLength" is the number of samples used to define the CP length (for example, Ts = 1 / 30.72 MHz (megahertz)). The segment extension information may include "freqOffset". "freqOffset" according to an embodiment defines the frequency offset of the carrier center frequency before additional filtering (for example, in the case of PRACH) and FFT processing (in the case of UL) in units of frequency offset factor. Meanwhile, when the segment extension information is applied to segment type 6 ("sectionType = 6"), the value of "FFT size" in frameStructure and cpLength may be set to "0".

[0176] According to an embodiment, the frequency offset information indicated by the section extension information may indicate a frequency offset based on a reference Figure 7 The frequency offset value of the mentioned scheme (e.g., Equation 7 to Equation 9, Table 7 to Table 10). The frequency offset value corresponds to the product of the SCS value of the frequency offset information indicated by the segment extension information and the frame structure information indicated by the segment extension information and the frequency offset factor. According to an embodiment, the frequency offset factor may be set based on the M-plane message. For example, for the M-plane message, the "fractFreqMode" information as an "optimal multi-vendo" item may indicate the frequency offset factor. According to an embodiment, the frequency offset factor may be set based on the C-plane message. For example, the LSB 4-bits of the frame structure information of the C-plane message may indicate the frequency offset factor.

[0177] Figure 9a An example of using a frequency offset factor to signal between a DU and a RU to provide a frequency offset through a management plane (M-plane) message and a C-plane message according to an embodiment is shown. Figure 2a According to an embodiment, the DU 210 may include an O-DU 251. Figure 2a According to an embodiment, the RU 220 may include an O-RU 253.

[0178] Reference Figure 9a In operation S901, the DU 210 may determine a frequency offset factor. The frequency offset factor may be used to determine an offset unit for indicating a frequency position of a lowest resource element resource element (RE) #0 of a lowest resource block (RB #0) relative to a center frequency. The offset unit may be determined by a product of the frequency offset factor and the SCS. According to an embodiment, the frequency offset factor may be 0.5. According to an embodiment, the frequency offset factor may be 0.25. According to an embodiment, the frequency offset factor may be 0.125.

[0179] The frequency offset value indicates the actual frequency distance from the center frequency to RE#0 of the allocated RB#0. However, the center frequency is determined in ARFCN units while RE is determined in SCS units, so the SCS units may not be sufficient to accurately display the frequency offset value. Therefore, the DU 210 according to the embodiment provides the frequency offset factor to the RU 220 through the mode information. The frequency offset factor implies a fractional value applied to the SCS to indicate the frequency offset value.

[0180] In operation S903, DU 210 may send a management plane (M-plane) message to RU 220. The M-plane message may include mode information. The mode information may indicate a frequency offset factor. According to an embodiment, the M-plane message may indicate a frequency offset factor through an optional multi-vendor function of the M-plane of the O-RAN standard. For example, "fractFreqMode" information may be added as a "best multi-vendor" item. For example, when the "fractFreqMode" information is 0, the frequency offset factor is 0.5. When the "fractFreqMode" information is 1, the frequency offset factor is 0.25. When the "fractFreqMode" information is 2, the frequency offset factor is 0.125. The value 3, 4, 5, 6, or 7 of the "fractFreqMode" information may be reserved for further use.

[0181] In operation S905, DU 210 may send a control plane (C-plane) message to RU 220. The C-plane message may include frequency offset information and parameter set information. The C-plane message may include frequency offset information. The frequency offset information may indicate the frequency domain from the carrier center frequency to the lowest RE resource element of the lowest RB in an offset unit. Here, the offset unit corresponds to the product of the frequency offset factor determined in operation S901 and the SCS provided by the parameter set information of the C-plane message. The C-plane message may include parameter set information. The parameter set information refers to a bit for indicating the SCS among the bits of the frame structure information of the C-plane message. The value of the bit for indicating the SCS may indicate the SCS by referring to Tables 6 to 10.

[0182] In operation S907, the RU 220 may obtain a frequency offset value, which is a product of the SCS provided by the C-plane message, the frequency offset factor provided by the mode information of the M-plane message, and the frequency offset information provided by the C-plane message.

[0183] In operation S909, the RU 220 may send a downlink signal. The RU 220 may generate an OFDM signal. The RU 220 may generate a downlink signal by modulation and up-conversion in the center frequency of the OFDM signal. The RU 220 may send a downlink signal to a user equipment (UE) in a cell. The RU 220 may send a downlink signal based on a frequency offset value. According to an embodiment, the downlink signal may include a synchronization signal. For example, the frequency band in which the downlink signal is transmitted may be FR 2 (or FR 2-1 or FR 2-2). The SCS of the synchronization signal may be 240 kHz, 480 kHz, or 960 kHz.

[0184] Figure 9b An example of using a frequency offset factor to signal between a DU and a RU to provide a frequency offset through a C-plane message according to an embodiment is shown. Figure 2a According to an embodiment, the DU 210 may include an O-DU 251. Figure 2a According to an embodiment, the RU 220 may include an O-RU 253.

[0185] Reference Figure 9b, in operation S951, DU 210 may send a control plane message to RU 220. The C-plane message may include frequency offset information and parameter set information. The C-plane message may include frequency offset information. The frequency offset information may indicate the frequency domain from the carrier center frequency to the lowest resource element (RE#0) of the lowest resource block (RB#0) in an offset unit. Here, the offset unit corresponds to the product of the frequency offset factor determined in step S901 and the SCS provided by the parameter set information of the C-plane message. The C-plane message may include parameter set information. The parameter set information refers to a bit used to indicate the SCS among the bits of the frame structure information of the C-plane message. The value of the bit used to indicate the SCS may indicate the SCS by referring to Tables 7 to 10.

[0186] In operation S953, the RU 220 may identify a value of the parameter set information. The parameter set information of the C-plane message according to an embodiment may indicate a frequency offset factor. The frequency offset factor may be used to determine an offset unit for indicating a frequency position of a lowest resource element (RE) of a lowest resource block (RB) relative to a center frequency. The offset unit is a product of a frequency offset factor and an SCS. According to an embodiment, the frequency offset factor may be 0.5. According to an embodiment, the frequency offset factor may be 0.25. According to an embodiment, the frequency offset factor may be 0.125.

[0187] The frequency offset value indicates the actual frequency distance from the center frequency to RE#0 of the allocated RB#0. However, the center frequency is determined in ARFCN units, while RE is determined in SCS units, so the SCS unit may not be sufficient to accurately display the frequency offset value. Therefore, the DU 210 according to the embodiment provides the frequency offset factor to the RU 220 through the parameter set information of the C-plane message. The frequency offset factor refers to a fractional value applied to the SCS to indicate the frequency offset value.

[0188] In operation S955, the RU 220 may identify an offset determination method. The offset determination method may depend on an offset factor. The offset determination method specifies a frequency offset factor. The RU 220 may identify the frequency offset factor based on a value of a bit of the parameter set information. According to an embodiment, the value of a bit of the parameter set information may indicate a frequency offset factor and an SCS. Based on a range to which the value of the bit of the parameter set information belongs, the RU 220 may identify the frequency offset factor. For example, the RU 220 may identify the offset determination method according to Equation 7. In addition, for example, the RU 220 may identify the offset determination method according to Equation 8. In addition, for example, the RU 220 may identify the offset determination method according to Equation 9.

[0189] In operation S957, the RU 220 may obtain a frequency offset value. The frequency offset value is the product of the SCS provided by the C-plane message, the frequency offset factor provided by the mode information of the M-plane message, and the frequency offset information provided by the C-plane message. The RU 220 may obtain the frequency offset value based on the offset determination method of operation S955. The RU 220 may obtain the frequency offset value based on the frequency offset factor identified in operation S955.

[0190] In operation S959, the DU 210 may send a downlink signal to the RU 220. The RU 220 may generate an OFDM signal. The RU 220 may generate a downlink signal by modulation and up-conversion in the center frequency of the OFDM signal. The RU 220 may send a downlink signal to a user equipment (UE) in the cell. The RU 220 may send the downlink signal based on a frequency offset value. According to an embodiment, the downlink signal may include a synchronization signal. For example, the frequency band in which the downlink signal is transmitted may be FR 2 (or FR 2-1 or FR 2-2). The SCS of the synchronization signal may be 240 kHz, 480 kHz, or 960 kHz.

[0191] exist Figures 7 to 9b In the embodiment of providing the frequency offset through the C-plane message, the embodiment of the present disclosure has been described, but the embodiments of the present disclosure are not limited thereto. According to another embodiment, the frequency offset factor may be indicated only by the M-plane message. The frequency offset factor substantially configured by the M-plane message may be 0.5, 0.25, or 0.125. The frequency offset factor substantially configured by the M-plane message may depend on the center of the SCS or the substantially configured channel bandwidth.

[0192] Fig.10 An example 1000 of signal processing of RUs in a hybrid parameter set channel according to an embodiment is shown. The RUs are shown Figure 2a According to an embodiment, the RU 220 may include an O-RU 253.

[0193] Reference Fig.10 , the RU may perform IFFT and add CP to the data signal 1011. The RU may perform filtering. The RU may perform IFFT and add CP to the synchronization signal 1013 (eg, SSB). Before performing filtering, the RU may perform compensation 1030 on the frequency converted component.

[0194] In FR2, the unit for searching the center frequency of the data signal 1011 is 60 kHz. In FR 2, the unit for searching the synchronization signal 1013 is 17280 kHz. According to the 3GPP standard, up-conversion of the synchronization signal 1013 is performed based on the carrier center frequency, and the carrier center frequency is identified in units of 60 kHz. Therefore, in the distance between the center frequency of the synchronization signal 1013 and the center frequency of the data signal 1011, in addition to the part distinguished by the multiple of the SCS, there may also be a remaining part. This remaining part is subject to compensation.

[0195] As described by Equations 3 to 5, the compensation target ( ) corresponds to a time-frequency conversion. Therefore, compensation 1030 can be performed in RU. From Equation 5, it can be seen that from the system bandwidth component ( ) and the frequency shift component ( ), the frequency can be relative to the center frequency of the system bandwidth ( ) offset correction value ( ).

[0196] The RU may receive frequency offset information from the DU via a fronthaul interface of the O-RAN. The RU may identify a frequency offset value based on the frequency offset information. The RU may determine a compensation component (e.g., a frequency offset component ( )). The RU may perform compensation 1030 on the synchronization signal 1013 based on the compensation component. For example, the RU may multiply the sampling unit in the time unit by To perform compensation 1030 of the synchronization signal 1013. The RU may perform filtering after compensation of the synchronization signal 1013.

[0197] The RU may perform up-conversion 1050 on the composite signal including the filtered data signal and the filtered synchronization signal. The up-conversion 1050 may be performed based on a carrier frequency (or a carrier center frequency). For example, the RU may perform up-conversion 1050 by multiplying the composite signal by The RU may output a downlink signal after performing up-conversion 1050.

[0198] According to an embodiment of the present disclosure, the RU may obtain an accurate frequency offset by using a frequency offset factor of a message received from the DU instead of using a fixed frequency offset factor.

[0199] According to an embodiment, a method performed by a radio unit (RU) may include: receiving a control plane (C-plane) message including frequency offset information and frame structure information for indicating a subcarrier spacing (SCS) from a distributed unit (DU). The method may include identifying a frequency offset factor among a plurality of frequency offset factors. The method may include acquiring a frequency offset value corresponding to a product of the frequency offset information, the SCS, and the frequency offset factor. The method may include sending a downlink signal based on the frequency offset value. The plurality of frequency offset factors may include "0.5" and "0.25".

[0200] According to an embodiment, the method may further include receiving a management plane (M-plane) message including pattern information indicating the frequency shift factor from the DU.

[0201] According to an embodiment, the frame structure information may include a bit indicating the SCS. When the value of the bit belongs to a first range, the identified frequency offset factor may be "0.5". When the value of the bit belongs to a second range different from the first range, the identified frequency offset factor may be "0.5".

[0202] According to an embodiment, the plurality of frequency offset factors may further include "0.125" and "0.0625".

[0203] According to an embodiment, the segment type of the C-plane message may be segment type 3 for a physical random access channel (PRACH) and a hybrid parameter set channel, and the frame structure information may be included in the segment information of the C-plane message. Alternatively, the segment type of the C-plane message may be segment type 5 for user equipment (UE) scheduling information or segment type 6 for transmitting UE channel information, and the frame structure information may be included in the segment extension information of the C-plane message.

[0204] According to an embodiment, a method performed by a distributed unit (DU) may include: determining frequency offset information related to a frequency offset factor among a plurality of frequency offset factors. The method may include sending a control plane (C-plane) message including segment information for a downlink signal, frequency offset information, and frame structure information for indicating a subcarrier spacing (SCS) to a radio frequency unit (RU). The frequency offset factor may be provided to the RU by a management plane (M-plane) message or a C-plane message. The frequency offset value applied to the downlink signal may correspond to the product of the frequency offset information, the SCS, and the frequency offset factor. The plurality of frequency offset factors may include "0.5" and "0.25".

[0205] According to an embodiment, the method may further include sending an M-plane message to the RU. The M-plane message may include pattern information indicating a frequency offset factor.

[0206] According to an embodiment, the frame structure information may include a bit indicating the SCS. When the value of the bit belongs to a first range, the identified frequency offset factor may be "0.5". When the value of the bit belongs to a second range different from the first range, the identified frequency offset factor may be "0.5".

[0207] According to an embodiment, the plurality of frequency offset factors may further include "0.125" and "0.0625".

[0208] According to an embodiment, the segment type of the C-plane message may be segment type 3 for a physical random access channel (PRACH) and a hybrid parameter set channel, and the frame structure information may be included in the segment information of the C-plane message. Alternatively, the segment type of the C-plane message may be segment type 5 for user equipment (UE) scheduling information or segment type 6 for transmitting UE channel information, and the frame structure information may be included in the segment extension information of the C-plane message.

[0209] According to an embodiment, the electronic device of the radio frequency unit (RU) may include at least one fronthaul transceiver, at least one radio frequency (RF) transceiver, and at least one processor coupled to the at least one fronthaul transceiver and the at least one RF transceiver. The at least one processor may be configured to receive a control plane (C-plane) message including frequency offset information and frame structure information indicating a subcarrier spacing (SCS) from a distributed unit (DU). The at least one processor may be configured to identify a frequency offset factor among a plurality of frequency offset factors. The at least one processor may be configured to obtain a frequency offset value corresponding to the product of the frequency offset information, the SCS, and the frequency offset factor. The at least one processor may be configured to send a downlink signal based on the frequency offset value. The plurality of frequency offset factors may include "0.5" and "0.25".

[0210] According to an embodiment, the at least one processor may be further configured to receive a management plane (M-plane) message including pattern information indicating a frequency shift factor from the DU.

[0211] According to an embodiment, the frame structure information may include a bit indicating the SCS. When the value of the bit belongs to a first range, the identified frequency offset factor may be "0.5". When the value of the bit belongs to a second range different from the first range, the identified frequency offset factor may be "0.5".

[0212] According to an embodiment, the plurality of frequency offset factors may further include "0.125" and "0.0625".

[0213] According to an embodiment, the segment type of the C-plane message may be segment type 3 for a physical random access channel (PRACH) and a hybrid parameter set channel, and the frame structure information may be included in the segment information of the C-plane message. Alternatively, the segment type of the C-plane message may be segment type 5 for user equipment (UE) scheduling information or segment type 6 for transmitting UE channel information, and the frame structure information may be included in the segment extension information of the C-plane message.

[0214] According to an embodiment, the electronic device of the distributed unit (DU) may include at least one transceiver and at least one processor coupled to the at least one transceiver. The at least one processor may be configured to determine frequency offset information related to a frequency offset factor among a plurality of frequency offset factors. The at least one processor may be configured to send a control plane (C-plane) message including segment information for a downlink signal, frequency offset information, and frame structure information for indicating a subcarrier spacing (SCS) to a radio frequency unit (RU). The frequency offset factor may be provided to the RU by a management plane (M-plane) message or a C-plane message. The frequency offset value applied to the downlink signal may correspond to the product of the frequency offset information, the SCS, and the frequency offset factor. Multiple frequency offset factors may include "0.5" and "0.25".

[0215] According to an embodiment, at least one processor may be further configured to send an M-plane message to the RU. The M-plane message may include pattern information indicating a frequency offset factor.

[0216] According to an embodiment, the frame structure information may include a bit indicating the SCS. When the value of the bit belongs to a first range, the identified frequency offset factor may be "0.5". When the value of the bit belongs to a second range different from the first range, the identified frequency offset factor may be "0.5".

[0217] According to an embodiment, the plurality of frequency offset factors may further include "0.125" and "0.0625".

[0218] According to an embodiment, the segment type of the C-plane message may be segment type 3 for a physical random access channel (PRACH) and a hybrid parameter set channel, and the frame structure information may be included in the segment information of the C-plane message. Alternatively, the segment type of the C-plane message may be segment type 5 for user equipment (UE) scheduling information or segment type 6 for transmitting UE channel information, and the frame structure information may be included in the segment extension information of the C-plane message.

[0219] The methods according to various embodiments described in the specification or claims of the present disclosure may be implemented in hardware, software, or a combination of hardware and software.

[0220] When implemented as software, a computer-readable storage medium storing one or more programs (software modules) may be provided. One or more programs stored in the computer-readable storage medium are configured to be executed by one or more processors in an electronic device. One or more programs include instructions that cause the electronic device to perform the method according to the embodiment described in the specification or claims of the present disclosure.

[0221] These programs (software modules or software) may be stored in random access memory, nonvolatile memory including flash memory, read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), magnetic disk storage device, compact disk ROM (CD-ROM), digital versatile disk (DVD), other types of optical storage devices, magnetic tape cassettes, etc. Alternatively, it may be stored in a memory configured by a combination of some or all of these. In addition, a plurality of corresponding constituent memories may be included.

[0222] In addition, the program may be stored in an attachable storage device accessible via a communication network, such as, for example, the Internet, an intranet, a local area network (LAN), a wide area network (WLAN), or a storage area network (SAN), or a communication network configured with a combination of these. Such a storage device may access the device executing the embodiments of the present disclosure via an external port. In addition, a separate storage device on the communication network may access the device executing the embodiments of the present disclosure.

[0223] In the above specific embodiments of the present disclosure, the elements included in the present disclosure are expressed in singular or plural form, depending on the specific embodiments presented. However, for ease of description, the singular form or plural form is selected to suit the situation in which it is presented, and the present disclosure is not limited to the singular elements or plural elements presented, and the components expressed in plural may be configured in singular form, or the components expressed in singular may be configured in plural form.

[0224] While specific embodiments have been described in the detailed description of the present disclosure, it will be apparent that many variations are possible without departing from the scope of the present disclosure.

Claims

1. A method performed by a radio frequency unit RU, the method comprising: Receiving a control plane message including frequency offset information and frame structure information indicating a subcarrier spacing SCS from a distributed unit DU, the control plane being the C plane; identifying a frequency offset factor among a plurality of frequency offset factors; Acquire a frequency offset value corresponding to a product of the frequency offset information, the SCS, and the frequency offset factor; as well as sending a downlink signal based on the frequency offset value, Among them, the multiple frequency offset factors include "0.5" and "0.25".

2. The method according to claim 1, further comprising: A management plane message including mode information indicating the frequency offset factor is received from the DU, where the management plane is the M-plane.

3. The method according to claim 1, in, The frame structure information includes a bit indicating the SCS, wherein, in the case where the value of the bit belongs to the first range, the identified frequency shift factor is "0.5", and Wherein, when the value of the bit belongs to a second range different from the first range, the identified frequency shift factor is "0.5".

4. The method according to claim 1, in, The multiple frequency offset factors also include "0.125" and "0.0625".

5. The method according to claim 1, in, The segment type of the C-plane message is segment type 3 for a physical random access channel PRACH and a hybrid parameter set channel, and the frame structure information is included in the segment information of the C-plane message, or The segment type of the C-plane message is segment type 5 for user equipment UE scheduling information or segment type 6 for sending UE channel information, and the frame structure information is included in the segment extension information of the C-plane message.

6. A method performed by a distributed unit DU, the method comprising: determining frequency offset information associated with a frequency offset factor among a plurality of frequency offset factors; as well as Sending a control plane message including segment information for a downlink signal, the frequency offset information, and frame structure information for indicating a subcarrier spacing SCS to a radio frequency unit RU, the control plane being the C plane, The frequency offset factor is provided to the RU by a management plane message or a C-plane message, and the management plane is the M-plane. wherein the frequency offset value applied to the downlink signal corresponds to the product of the frequency offset information, the SCS and the frequency offset factor, and Among them, the multiple frequency offset factors include "0.5" and "0.25".

7. The method according to claim 6, further comprising: Sending the M-plane message to the RU, The M-plane message includes mode information indicating the frequency offset factor.

8. The method according to claim 6, in, The frame structure information includes a bit indicating the SCS, wherein, in the case where the value of the bit belongs to the first range, the identified frequency shift factor is "0.5", and Wherein, when the value of the bit belongs to a second range different from the first range, the identified frequency shift factor is "0.5".

9. The method according to claim 6, in, The multiple frequency offset factors also include "0.125" and "0.0625".

10. The method according to claim 6, in, The segment type of the C-plane message is segment type 3 for a physical random access channel PRACH and a hybrid parameter set channel, and the frame structure information is included in the segment information of the C-plane message, or The segment type of the C-plane message is segment type 5 for user equipment UE scheduling information or segment type 6 for sending UE channel information, and the frame structure information is included in the segment extension information of the C-plane message.

11. An electronic device of a radio frequency unit RU, the electronic device comprising: at least one fronthaul transceiver; at least one radio frequency (RF) transceiver; at least one processor coupled to the at least one fronthaul transceiver and the at least one RF transceiver, Wherein, the at least one processor is configured to: Receiving a control plane message including frequency offset information and frame structure information indicating a subcarrier spacing SCS from a distributed unit DU, the control plane being the C plane; identifying a frequency offset factor among a plurality of frequency offset factors; Acquire a frequency offset value corresponding to a product of the frequency offset information, the SCS, and the frequency offset factor; and sending a downlink signal based on the frequency offset value, Among them, the multiple frequency offset factors include "0.5" and "0.25".

12. The electronic device according to claim 11, wherein: The at least one processor is configured to perform the method according to one of claims 2 to 5.

13. An electronic device of a distributed unit DU, the electronic device comprising: at least one fronthaul transceiver; at least one radio frequency (RF) transceiver; at least one processor coupled to the at least one fronthaul transceiver and the at least one RF transceiver, Wherein, the at least one processor is configured to: determining frequency offset information associated with a frequency offset factor among a plurality of frequency offset factors; and Sending a control plane message including segment information for a downlink signal, the frequency offset information, and frame structure information for indicating a subcarrier spacing SCS to a radio frequency unit RU, the control plane being the C plane, The frequency offset factor is provided to the RU by a management plane message or a C-plane message, and the management plane is the M-plane. wherein the frequency offset value applied to the downlink signal corresponds to the product of the frequency offset information, the SCS and the frequency offset factor, and Among them, the multiple frequency offset factors include "0.5" and "0.25".

14. The electronic device according to claim 13, wherein: The at least one processor is configured to perform the method according to one of claims 7 to 10.

Images