Apparatus and method for front-haul transmission in wireless communication systems

Abstract

This disclosure relates to 4G (4G) such as LTE (Long Term Evolution). th 5G (5th Generation) communication systems to support higher data transmission rates th According to an embodiment of the present disclosure, a digital unit (DU) device in a wireless communication system includes a transceiver and at least one processor, the at least one processor is configured to set a section extension field including additional information, and transmit a first control message including the section extension field to a radio unit (RU) via a fronthaul interface, the first control message being used to schedule a terminal in a control plane.

Description

Technical Field

[0001] The present disclosure generally relates to wireless communication systems, and more specifically, to an apparatus and method for transmitting multiple sub-carrier spacing signals in a fronthaul of a wireless communication system.

Background Art

[0002] 4G(4 th generation) After the commercialization of communication systems, in order to meet the increasing demand for wireless data traffic, efforts have been made to develop improved 5G(5 th generation) communication systems or pre-5G communication systems. For this reason, 5G communication systems or pre-5G communication systems are called communication systems Beyond 4G Network or Post LTE systems after the 4G network.

[0003] To achieve high data transmission rates, the 5G communication system is considered to be implemented in the millimeter wave (mmWave) band (for example, the 60 gigahertz (60 GHz) band, etc.). In order to mitigate the path loss of radio waves in the millimeter wave band and increase the transmission distance of radio waves, in the 5G communication system, beamforming, massive MIMO (multiple input multiple output), full dimensional MIMO (FD-MIMO), array antenna, analog beamforming and large scale antenna technologies have been discussed.

[0004] Furthermore, in order to improve the system's network, 5G communication systems are undergoing technological development, including advanced small cells, cloud radio access networks (cloud RAN), ultra-dense networks, device-to-device communication (D2D), wireless backhaul, moving networks, cooperative communication, CoMP (Coordinated Multi-Points), and interference cancellation.

[0005] In addition, 5G systems have seen the development of advanced coding modulation (ACM) methods such as FQAM (Hybrid Frequency Shift Keying and Quadrature Amplitude Modulation) and SWSC (Sliding Window Superposition Coding), as well as advanced access technologies such as FBMC (Filter Bank Multi Carrier), NOMA (Non Orthogonal Multiple Access), and SCMA (Sparse Code Multiple Access).

[0006] As transmission capacity increases in wireless communication systems, function splitting is being applied to functionally separate base stations. Through function splitting, a base station can be separated into a DU (digital unit) and an RU (radio unit), a fronthaul is defined for communication between the DU and the RU, and transmission via the fronthaul is required. [Overview of the Initiative] [Problems that the invention aims to solve]

[0007] Based on the above discussion, this disclosure provides an apparatus and method for transmitting multiplexed subcarrier signals over a fronthaul interface.

[0008] Furthermore, this disclosure provides apparatus and methods relating to a novel form of section type and configuration for providing mixed numerology-related information.

[0009] Furthermore, this disclosure provides a frame format for section extensions and associated apparatus and methods for transmitting mixed numerology-related information. [Means for solving the problem]

[0010] According to one embodiment of the present disclosure, the operation method of a digital unit (DU) in a wireless communication system includes the steps of setting a section extension field containing additional information and transmitting a first control message containing the section extension field to a radio unit (RU) via a fronthaul interface, the first control message may be used to schedule a terminal on the control plane.

[0011] According to one embodiment of the present disclosure, the operation method of a radio unit (RU) in a wireless communication system includes the process of receiving a first control message from a digital unit (DU) via a fronthaul interface, the section extension field including additional information, the section extension field being set by the DU, and the first control message being used to schedule a terminal on a control plane.

[0012] According to one embodiment of the present disclosure, a digital unit (DU) device in a wireless communication system includes a transceiver and at least one processor, the at least one processor configured to set a section extension field containing additional information and to transmit a first control message containing the section extension field to a radio unit (RU) via a fronthaul interface, the first control message may be used to schedule a terminal on a control plane.

[0013] According to one embodiment of the present disclosure, a radio unit (RU) in a wireless communication system includes a transceiver and at least one processor, the at least one processor configured to receive a first control message from a digital unit (DU) via a fronthaul interface, the section extension field including additional information, the section extension field being set by the DU, and the first control message being used to schedule a terminal on a control plane. [Effects of the Invention]

[0014] According to an apparatus and method in one embodiment of the present disclosure, mixed numerology-related information is provided via a new type of section, thereby enabling effective operation of the DU (digital unit) and RU (radio unit) interfaces.

[0015] The effects obtained by this disclosure are not limited to those mentioned above, and any other effects not mentioned above will be clearly understood by a person with ordinary skill in the art to which this disclosure pertains from the following description.

Brief Description of Drawings

[0016] [Figure 1A] It is a diagram showing a wireless communication system according to an embodiment of the present disclosure. [Figure 1B] It is a diagram showing an example of a fronthaul structure by functional separation of a base station according to an embodiment of the present disclosure. [Figure 2] It is a diagram showing the configuration of a DU (Digital Unit) according to an embodiment of the present disclosure. [Figure 3] It is a diagram showing the configuration of a RU (Radio Unit) according to an embodiment of the present disclosure. [Figure 4] It is a diagram showing an example of functional separation (function split) according to an embodiment of the present disclosure. [Figure 5] It is a diagram showing an example of a BWP configuration according to an embodiment of the present disclosure. [Figure 6A] It is a diagram showing examples of various new forms of section types and configurations according to an embodiment of the present disclosure. [Figure 6B] It is a diagram showing other examples of various new forms of section types and configurations according to an embodiment of the present disclosure. [Figure 6C] It is a diagram showing still other examples of various new forms of section types and configurations according to an embodiment of the present disclosure. [Figure 6D] It is a diagram showing still other examples of various new forms of section types and configurations according to an embodiment of the present disclosure. [Figure 7] It is a diagram showing an example of the connection between a DU and a RU according to an embodiment of the present disclosure.

Modes for Carrying Out the Invention

[0017] The terms used in this disclosure are merely used to describe specific embodiments and are not intended to limit the scope of other embodiments. Singular expressions can include plural expressions unless the context clearly indicates a different meaning. Terms used herein, including technical or scientific terms, can have the same meaning as generally understood by those having ordinary knowledge in the technical field described in this disclosure. Among the terms used in this disclosure, terms defined in a general dictionary can be interpreted as having the same or similar meaning as their meaning in the context of the related art, and are not interpreted as having an ideal or overly formal meaning unless clearly defined in this disclosure. In some cases, even terms defined in this disclosure cannot be interpreted so as to exclude embodiments of this disclosure.

[0018] In various embodiments of the disclosure described below, a hardware approach is illustrated as an example. However, since various embodiments of the disclosure include techniques that use both hardware and software, various embodiments of the disclosure do not exclude software-based approaches.

[0019] The following terms used in the explanation are illustrative examples for the sake of clarity, including terms referring to signals (e.g., message, information, preamble, signal, signaling, sequence, stream), resources (e.g., symbol, slot, subframe, radio frame, subcarrier, RE (resource element), RB (resource block), BWP (bandwidth part), occasion), operational states (e.g., step, operation, procedure), data (e.g., packet, user stream, information, bit, symbol, codeword), channels, control information (e.g., DCI (downlink control information), MAC CE (medium access control element), RRC (radio resource control) signaling), network entities, and device components. Therefore, this disclosure is not limited to the terms described below, and other terms with equivalent technical meanings may be used.

[0020] Furthermore, while the expressions "greater than" or "less than" may be used in this disclosure to determine whether a particular condition is satisfied or fulfilled, this is merely an example and does not preclude the use of "greater than or equal to" or "less than or equal to." Conditions described as "greater than or equal to" may be replaced with "greater than," conditions described as "less than or equal to" may be replaced with "less than," and conditions described as "greater than or equal to and less than" may be replaced with "greater than and less than."

[0021] This disclosure uses terminology from certain communication standards (e.g., 3GPP® (3rd Generation Partnership Project), xRAN (extensible radio access network), O-RAN (open-radio access network)) to describe various embodiments, but these are merely illustrative examples. Various embodiments of this disclosure can be easily modified and applied to other communication systems.

[0022] Figure 1A illustrates a wireless communication system according to various embodiments of the present disclosure. Figure 1A illustrates a base station 110, terminal 120, and terminal 130 as part of a node utilizing a radio channel in the wireless communication system. Although Figure 1A illustrates only one base station, other base stations identical or similar to base station 110 may be further included.

[0023] Base station 110 is network infrastructure that provides wireless connectivity to terminals 120 and 130. Base station 110 has coverage defined in a predetermined geographical area based on the distance over which it can transmit signals. In addition to base station, base station 110 can also be referred to as "access point (AP)", "eNodeB (eNB)", "5G node (5th generation node)", "next generation nodeB (gNB)", "wireless point", "transmission / reception point (TRP)", or other terms with equivalent technical meaning.

[0024] Terminals 120 and 130 are devices used by the user and communicate with base station 110 via a radio channel. The link from base station 110 to terminal 120 or terminal 130 is called a downlink (DL), and the link from terminal 120 or terminal 130 to base station 110 is called an uplink (UL). Terminals 120 and 130 can also communicate with each other via a radio channel. In this case, the link between terminals 120 and 130 (device-to-device link; D2D) is called a sidelink, and the sidelink may be used interchangeably with the PC5 interface. In some cases, at least one of terminals 120 and 130 can be operated without user involvement. That is, at least one of terminals 120 and 130 may be a device that performs machine-type communication (MTC) and may not be carried by the user. Each of terminals 120 and 130 may be referred to as "terminal," "user equipment (UE)," "customer premises equipment (CPE)," "mobile station," "subscriber station," "remote terminal," "wireless terminal," "electronic device," or "user device," or any other term with equivalent technical meaning.

[0025] Base station 110, terminal 120, and terminal 130 can perform beamforming. The base station and terminals can transmit and receive radio signals in a relatively low frequency band (e.g., FR1 (frequency range 1) of NR). Also, the base station and terminals can transmit and receive radio signals in a relatively high frequency band (e.g., FR2 of NR, millimeter wave (mmWave) band (e.g., 28GHz, 30GHz, 38GHz, 60GHz)). In some embodiments, base station 110 can communicate with terminal 110 within the frequency range corresponding to FR1. In some embodiments, base station 120 can communicate with terminal 120 within the frequency range corresponding to FR2. In this case, to improve channel gain, base station 110, terminal 120, and terminal 130 can perform beamforming. Here, beamforming can include transmit beamforming and receive beamforming. That is, base station 110, terminal 120, and terminal 130 can give directivity to the transmitted or received signal. To this end, the base station 110 and terminals 120 and 130 can select a serving beam by beam search or beam management procedures. After the serving beam is selected, communication may take place between the resource that transmitted the serving beam and resources that are in a QCL relationship with it.

[0026] The first and second antenna ports can be described as being in a QCL relationship if the large-scale characteristics of the channel that transmitted symbols on the first antenna port can be inferred from the channel that transmitted symbols on the second antenna port. For example, the large-scale characteristics may include at least one of the following: delay spread, Doppler spread, Doppler shift, average gain, average delay, and spatial receiver parameter.

[0027] Although Figure 1A illustrates that both the base station and the terminal perform beamforming, the various embodiments of this disclosure are not necessarily limited to this. In some embodiments, the terminal may or may not perform beamforming. Similarly, the base station may or may not perform beamforming. In other words, only one of the base station or the terminal may perform beamforming, or neither the base station nor the terminal may perform beamforming.

[0028] In this disclosure, a beam refers to the spatial flow of a signal in a radio channel, formed by one or more antennas (or antenna elements), and such a formation process can be called beamforming. Beamforming can include analog beamforming and digital beamforming (e.g., precoding). Reference signals transmitted based on beamforming can include, for example, DM-RS (demodulation-reference signal), CSI-RS (channel state information-reference signal), SS / PBCH (synchronization signal / physical broadcast channel), and SRS (sounding reference signal). Furthermore, IEs such as CSI-RS resource or SRS-resource can be used as configurations for each reference signal, and such configurations can include information associated with the beam. The information associated with the beam can indicate whether the configuration in question (e.g., a CSI-RS resource) uses the same spatial domain filter as other configurations (e.g., other CSI-RS resources within the same CSI-RS resource set), or uses a different spatial domain filter, or which reference signal it is quasi-co-located with, and if so, what type of QCL it is (e.g., QCL type A, B, C, D).

[0029] Traditionally, in communication systems with relatively large base station cell radii, each base station was installed to include both a digital processing unit (DU) and an RF (radio frequency) processing unit (RU). However, 4G (4th In the 2000 generation and / or subsequent communication systems, high frequency bands are used, resulting in smaller base station cell radii and an increased number of base stations required to cover a specific area, which in turn increases the installation costs for operators. To minimize base station installation costs, a structure has been proposed in which the base station's DU and RU are separated, with one or more RUs connected to a single DU via a wired network, and one or more RUs are geographically distributed to cover a specific area. Below, with reference to Figure 1B, examples of base station configurations and extensions according to various embodiments of this disclosure will be described.

[0030] Figure 1B shows examples of fronthaul structures with functional isolation of base stations according to various embodiments of this disclosure. Unlike backhaul, which is between the base station and the core network, fronthaul refers to the space between the wireless LAN and the base station.

[0031] Referring to Figure 1B, base station 110 can include DU160 and RU180. The fronthaul 170 between DU160 and RU180 is F x It can be operated via an interface. For the operation of the fronthaul 170, interfaces such as eCPRI (enhanced common public radio interface) and ROE (radio over ethernet) may be used.

[0032] As communication technology advances, mobile data traffic increases, significantly raising the bandwidth requirements for the fronthaul between digital and radio units. In configurations like C-RAN (centralized / cloud radio access network), the DU (Digital Unit) can be implemented to perform functions related to the PDCP (packet data convergence protocol), RLC (radio link control), MAC (media access control), and PHY (physical) layers, while the RU (Radio Unit) can perform more functions related to the PHY layer in addition to RF (radio frequency) functions.

[0033] The DU160 can perform higher-layer functions of a wireless network. For example, the DU160 can perform MAC layer functions and parts of the PHY layer. Here, parts of the PHY layer refer to functions performed at a higher level of the PHY layer, and may include, for example, channel encoding (or channel decoding), scrambling (or descrambling), modulation (or demodulation), and layer mapping (or layer demapping). According to one embodiment, if the DU160 conforms to the O-RAN standard, it may be referred to as O-DU (O-RAN DU). The DU160 may, as necessary, be represented in place of a first network entity for a base station (e.g., gNB) in embodiments of this disclosure.

[0034] The RU180 can handle lower-layer functions of a wireless network. For example, the RU180 can perform some of the PHY layer functions, specifically RF functions. Here, "some of the PHY layer functions" refers to functions performed at a relatively lower level than those of the DU160, and may include, for example, IFFT conversion (or FFT conversion), CP insertion (CP rejection), and digital beamforming. Specific examples of such functional separation are described in detail in Figure 4. The RU180 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 with equivalent technical meaning. In one embodiment, if the RU180 conforms to the O-RAN standard, it may be referred to as an O-RU (O-RAN RU). The DU180 may, as necessary, be used in place of a second network entity for a base station (e.g., gNB) in embodiments of this disclosure.

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

[0036] A CU (centralized unit) is connected to one or more DUs and can perform functions at higher layers than the DUs. For example, a CU can perform functions at the RRC (radio resource control) and PDCP (packet data convergence protocol) layers, while the DU and RU can perform functions at lower layers. A DU can perform functions at the RLC (radio link control), MAC (media access control), and some functions at the PHY (physical) layer (high PHY), while the RU can perform the remaining functions at the PHY layer (low PHY). Also, as an example, a DU (digital unit) may be included in a DU (distributed unit) through the implementation of a distributed base station deployment. Hereafter, unless otherwise defined, the operation of DUs (digital units) and RUs will be described, but the various embodiments of this disclosure can be applied to either base station deployments including CUs or deployments in which DUs are directly connected to the core network without CUs (i.e., CUs and DUs are integrated and implemented in a single entity).

[0037] Figure 2 shows the configuration of a radio unit (DU) in a wireless communication system according to one embodiment of the present disclosure. The configuration illustrated in Figure 2 is part of a base station and can be understood as the configuration of DU160 in Figure 1B. The terms "~unit" and "~device" used hereafter refer to a unit that processes at least one function or operation, which may be implemented in hardware, software, or a combination of hardware and software.

[0038] Referring to Figure 2, the DU160 includes a communication unit 210, a storage unit 220, and a control unit 230.

[0039] The communication unit 210 can perform functions for sending and receiving signals in a wired communication environment. The communication unit 210 may include a wired interface for controlling direct connections between devices via a transmission medium (e.g., copper wire, optical fiber). For example, the communication unit 210 can transmit electrical signals to other devices via copper wire or perform conversions between electrical signals and optical signals. The communication unit 210 may be connected to a radio unit (RU). The communication unit 210 may be connected to a core network or to a distributed CU.

[0040] The communication unit 210 can also perform functions for sending and receiving signals in a wireless communication environment. For example, the communication unit 210 can perform conversion functions between baseband signals and bit sequences according to the system's physical layer specifications. For example, when transmitting data, the communication unit 210 generates complex symbols by encoding and modulating the transmitted bit sequence. When receiving data, the communication unit 210 restores the received bit sequence by demodulating and decoding the baseband signal. The communication unit 210 can also include a number of transmission and reception paths. Furthermore, according to one embodiment, the communication unit 210 may be connected to a core network or to other nodes (e.g., an IAB (integrated access backhaul)).

[0041] The communication unit 210 can transmit and receive signals. For this purpose, the communication unit 210 may include at least one transceiver. For example, the communication unit 210 can transmit synchronization signals, reference signals, system information, messages, control messages, streams, control information, or data. The communication unit 210 can also perform beamforming.

[0042] The communication unit 210 transmits and receives signals as described above. Therefore, all or part of the communication unit 210 can be referred to as the "transmitting unit," the "receiving unit," or the "transmitting / receiving unit." In the following explanation, transmission and reception performed via the wireless channel are used to mean that the communication unit 210 performs the processing described above.

[0043] Although not shown in Figure 2, the communication unit 210 may further include a backhaul communication unit for connecting to the core network or other base stations. The backhaul communication unit provides an interface for communicating with other nodes in the network. That is, the backhaul communication unit converts bit streams transmitted from the base station to other nodes, such as other connecting nodes, other base stations, higher-level nodes, and the core network, into physical signals, and converts physical signals received from other nodes into bit streams.

[0044] The storage unit 220 stores data such as the basic program for the operation of the DU160, application programs, and configuration information. The storage unit 220 may include memory. The storage unit 220 may consist of volatile memory, non-volatile memory, or a combination of volatile and non-volatile memory. The storage unit 220 then provides the stored data in response to requests from the control unit 230.

[0045] The control unit 230 controls the overall operation of the DU160. For example, the control unit 230 transmits and receives signals via the communication unit 210 (or via the backhaul communication unit). The control unit 230 also records and reads data from the storage unit 220. Furthermore, the control unit 230 can perform the functions of the protocol stack required by the communication standard. To this end, the control unit 230 may include at least one processor.

[0046] According to one embodiment, the control unit 230 may include a message setting unit. The message setting unit included in the control unit 230 can set section extension fields. The control unit 230 can control the transmitting and receiving unit to transmit control messages to the RU170. According to one embodiment, the control unit 230 can control the DU160 to perform the operation according to one embodiment described later.

[0047] The configuration of DU160 shown in Figure 2 is merely an example, and the configuration shown in Figure 2 does not limit the examples of DUs that perform one embodiment of the present disclosure. According to one embodiment, some configurations may be added, deleted, or modified.

[0048] Figure 3 shows the configuration of a radio unit (RU) in a wireless communication system according to one embodiment of the present disclosure. The configuration illustrated in Figure 3 is part of a base station and can be understood as the configuration of RU180 in Figure 1B. The terms "~unit" and "~device" used hereafter refer to a unit that processes at least one function or operation, which may be implemented in hardware, software, or a combination of hardware and software.

[0049] Referring to Figure 3, RU180 includes a communication unit 310, a storage unit 320, and a control unit 330.

[0050] The communication unit 310 performs functions for transmitting and receiving signals via a wireless channel. For example, the communication unit 310 upconverts a baseband signal to an RF band signal and transmits it via an antenna, and downconverts the RF band signal received via the antenna back to a baseband signal. For example, the communication unit 310 may include a transmit filter, a receive filter, an amplifier, a mixer, an oscillator, a DAC (digital to analog converter), an ADC (analog to digital converter), and so on.

[0051] Furthermore, the communication unit 310 can include a number of transmit and receive paths. Moreover, the communication unit 310 can include an antenna unit. The communication unit 310 can include at least one antenna array composed of a number of antenna elements. From a hardware standpoint, the communication unit 310 can consist of digital and analog circuits (e.g., an RFIC (radio frequency integrated circuit)). Here, the digital and analog circuits can be implemented in a single package. The communication unit 310 can also include a number of RF chains. The communication unit 310 can perform beamforming. The communication unit 310 can apply a beamforming weight to a signal to give the signal to be transmitted or received a directivity setting in the control unit 330. According to one embodiment, the communication unit 310 can include an RF (radio frequency) block (or RF unit).

[0052] Furthermore, the communication unit 310 can transmit and receive signals. For this purpose, the communication unit 210 may include at least one transceiver. The communication unit 310 can transmit downlink signals. Downlink signals may include synchronization signals (SS), reference signals (RS) (e.g., CRS (cell-specific reference signal), DM (demodulation)-RS), system information (e.g., MIB, SIB, RMSI (remaining system information), OSI (other system information)), configuration messages, control information, or downlink data. The communication unit 310 can also receive uplink signals. Uplink signals may include random access-related signals (e.g., random access preamble (RAP) (or Msg1 (message 1)), Msg3 (message 3)), reference signals (e.g., SRS (sounding reference signal), DM-RS), or power headroom reports (PHR).

[0053] The communication unit 310 transmits and receives signals as described above. Therefore, all or part of the communication unit 310 can be referred to as the "transmitting unit," the "receiving unit," or the "transmitting / receiving unit." In the following explanation, transmission and reception performed via the wireless channel are used to mean that the communication unit 310 performs the processing described above.

[0054] The storage unit 320 stores data such as the basic program for the operation of the RU180, application programs, and configuration information. The storage unit 320 may consist of volatile memory, non-volatile memory, or a combination of volatile and non-volatile memory. The storage unit 320 then provides the stored data in response to requests from the control unit 330. According to one embodiment, the storage unit 320 may include memory for conditions, instructions, or settings related to the SRS transmission method.

[0055] The control unit 330 controls the overall operation of the RU180. For example, the control unit 330 transmits and receives signals via the communication unit 310. The control unit 330 also records and reads data from the storage unit 320. Furthermore, the control unit 330 can perform the functions of the protocol stack required by the communication standard. To this end, the control unit 330 may include at least one processor. In some embodiments, the control unit 330 can be configured to receive control messages that include section extension fields set in the DU. Also in some embodiments, the control unit 330 may be configured to receive parameters related to mixed numerology via control messages. According to one embodiment, the control unit 330 can control the RU170 to perform the operation according to one embodiment described later.

[0056] Figure 4 shows an example of function splitting in a wireless communication system according to one embodiment of the present disclosure. As wireless communication technology develops (e.g., 5G (5 thWith the introduction of 5G communication systems (or NR (new radio) communication systems), the number of RUs required for installation has increased further due to the increased frequency bandwidth and the extremely small cell radius of base stations. In addition, with 5G communication systems, the amount of data transmitted has increased more than tenfold, and the transmission capacity of the wired network transmitted in the fronthaul has increased significantly. Due to these factors, the installation cost of wired networks in 5G communication systems can increase very significantly. Therefore, in order to reduce the transmission capacity of the wired network and reduce the installation cost of the wired network, a technology has been proposed that reduces the transmission capacity of the fronthaul by handing over some functions of the DU's modem to the RU, and such a technology can be called "function split".

[0057] To reduce the burden on the DU, a method is considered to extend the role of the RU, which is currently only responsible for RF functions, to include some physical layer functions. In this case, the higher the layer functions the RU performs, the greater the processing load of the RU, which increases the transmission bandwidth in the fronthaul and may reduce the constraints on delay time requirements due to response processing. On the other hand, the higher the layer functions the RU performs, the less virtualization gain there is, and the larger / heavy / cost of the RU increases. Considering the trade-offs of the above advantages and disadvantages, it is necessary to implement the optimal functional separation.

[0058] Referring to Figure 4, the functional separation at the physical layers below the MAC layer is illustrated. In the case of downlink (DL), which transmits signals to terminals over a wireless network, the base station can sequentially perform channel encoding / scrambling, modulation, layer mapping, antenna mapping, RE mapping, digital beamforming (e.g., precoding), IFFT conversion / CP insertion, and RF conversion. In the case of uplink (UL), which receives signals from terminals over a wireless network, the base station can sequentially perform RF conversion, FFT conversion / CP rejection, digital beamforming (pre-combining), RE demapping, channel estimation, layer demapping, demodulation, and decoding / discrambling. The separation of uplink and downlink functions can be defined in various types depending on the trade-offs described above, the needs between vendors, and the discussions in standards.

[0059] The first functional separation 405 can be the separation of RF and PHY functions. The first functional separation is one in which the PHY function within the RU is not implemented, and can be referred to as Option 8, for example. The second functional separation 410 is one in which the RU performs IFFT conversion / CP insertion at DL (downlink) and FFT conversion / CP removal at UL (uplink) of the PHY function, and the DU performs the remaining PHY function. For example, the second functional separation 410 can be referred to as Option 7-1. The third functional separation 420a is one in which the RU performs IFFT conversion / CP insertion at DL and FFT conversion / CP removal and digital beamforming at UL of the PHY function, and the DU performs the remaining PHY function. For example, the third functional separation 420a can be referred to as Option 7-2x Category A. The fourth functional separation 420b is one in which the RU performs digital beamforming at both DL and UL, and the DU performs the higher-level PHY function after digital beamforming. For example, the fourth function separation 420b can be referred to as Option 7-2x Category B. The fifth function separation 425 has the RU perform RE mapping (or RE demapping) in both DL and UL, and the DU perform the higher-level PHY functions after RE mapping (or RE demapping). For example, the fifth function separation 425 can be referred to as Option 7-2. The sixth function separation 430 has the RU perform modulation (or demodulation) in both DL and UL, and the DU perform the higher-level PHY functions after modulation (or demodulation). For example, the sixth function separation 430 can be referred to as Option 7-3. The seventh function separation 440 has the RU perform encoding / scrambling (or decoding / discrambling) in both DL and UL, and the DU perform the higher-level PHY functions after modulation (or demodulation). For example, the seventh function separation 440 can be referred to as Option 6.

[0060] According to one embodiment, when large-capacity signal processing is expected, such as in an FR1 MMU (massive MIMO unit), functional isolation at a relatively high layer (e.g., fourth functional isolation 420b) may be required to reduce fronthaul capacitance. On the other hand, functional isolation at an excessively high layer (e.g., sixth functional isolation 430) can complicate the control interface and include a large number of PHY processing blocks within the RU, potentially burdening the implementation of the RU. Therefore, appropriate functional isolation may be required depending on the arrangement and implementation method of the DU and RU.

[0061] According to one embodiment, if the precoding of data received from the DU cannot be processed (i.e., the RU's precoding capability is limited), a third functional isolation 420a or lower (e.g., a second functional isolation 410) may be applied. Conversely, if the RU has the capability to process the precoding of data received from the DU, a fourth functional isolation 420b or higher (e.g., a sixth functional isolation 430) may be applied. Hereinafter, unless otherwise specified, an embodiment in this disclosure will be described based on a third functional isolation 420a (category A) or a fourth functional isolation 420b (category B) for beamforming processing in the RU, but this does not preclude the configuration of embodiments using other functional isolations. The functional configurations, signaling, or operations described in Figures 5 to 7 below may apply not only to the third functional isolation 420a or the fourth functional isolation 420b but also to other functional isolations.

[0062] One embodiment of this disclosure illustrates the use of eCPRI and O-RAN standards as fronthaul interfaces during message transmission between a DU (e.g., DU160 in Figure 1B) and an RU (e.g., RU180 in Figure 1B). The Ethernet payload of the message may include an eCPRI header, an O-RAN header, and additional fields. Hereafter, one embodiment of this disclosure will be described using eCPRI or O-RAN standard terminology, but other expressions with equivalent meanings may be used in place of one embodiment of this disclosure.

[0063] The fronthaul transport protocol can be Ethernet or eCPRI, which are easily shared across the network. The Ethernet payload may include an eCPRI header and an O-RAN header. The eCPRI header may be located at the front end of the Ethernet payload. The contents of the eCPRI header are as follows:

[0064] - ecpriVersion(4 bits):0001b(fixed value) - ecpriReserved(3 bits):0000b(fixed value) - ecpriConcatenation(1 bit):0b(fixed value) - ecpriMessage(1 byte):Message type - ecpriPayload(2 bytes):Payload size in bytes - ecpriRtcid / ecpriPcid (2 bytes): x, y, and z may be configured by the management plane (M-plane). The relevant field can indicate the transmission path of a control message according to one embodiment during multi-layer transmission (eAxC (extended Antenna-carrier) in eCPRI).

[0065] - CU_Port_ID (x bits): Identifies the channel card. Can include the modem as well (2 bits for channel card, 2 bits for modem). - BandSector_ID(y bits): Distributed by Cell / Sector - CC_ID (z bits): Differentiated by Component carrier - RU_Port_ID(w bits): Distinguished by layer, T, antenna, etc. - ecpriSeqid (2 bytes): Sequence IDs are managed separately for ecpriRtcid / ecpriPcid, and both Sequence ID and subsequence ID are managed separately. Radio-transport-level fragmentation is possible using the subsequence ID (this differs from application-level fragmentation). The fronthaul application protocol may include the control plane (C-plane), user plane (U-plane), synchronization plane (S-plane), and management plane (M-plane).

[0066] The control plane may be configured to provide scheduling and beamforming information via control messages. The user plane may include user downlink data (IQ data or SSB (synchronization signal block) / RS), uplink data (IQ data or SRS / RS), or PRACH (physical random access channel) data. The weighted vector of the beamforming information described above may be multiplied by the user data. The synchronization plane may be associated with timing and synchronization. The management plane may be associated with initial setup, non-realtime reset or reset, and non-realtime reporting.

[0067] Section Types are defined to define the types of messages transmitted on the control plane. A Section Type can indicate the purpose of a control message transmitted on the control plane. For example, the purposes of different Section Types are as follows:

[0068] - sectionType=0:DL idle / guard periods - Tx blanking application for power saving - sectionType=1: Map BF index or weight (O-RAN mandatory BF (beamforming) method) to the RE of DL / UL channels. - sectionType=2:reserved - sectionType=3: Map beamforming index or weight to the RE (resource element) of PRACH and mixed-numerology channels. - sectionType=4:reserved - sectionType=5: Transmit UE scheduling information so that the RU can perform real-time BF weight calculation (O-RAN optional BF method) - sectionType=6: Periodically transmit UE channel information so that the RU can perform real-time BF weight calculation (O-RAN optional BF method) - sectionType=7: Used for LAA support

[0069] In this disclosure, “numerology” is used as a term meaning a variable or set of variables related to the structure of a physical signal. Numerology can represent at least one of various variables that cause changes in a physical signal, such as subcarrier spacing, symbol duration, cyclic prefix (CP) duration, fast Fourier transform (FFT), sampling rate, subframe length, and frame length. Therefore, “mixed numerology” describes a situation in which various physical structures coexist, and “supporting mixed numerology” means that a single base station or system provides different physical structures from each other. Thus, “numerology” can be referred to as “configuration,” “physical layer configuration,” “frame configuration,” “configuration,” “signal structure,” “physical layer structure,” “frame structure,” or another name with equivalent technical meaning.

[0070] In NR, as the frequency bandwidth used increases, terminal and base station signaling becomes broadband. Due to limitations in terminal capabilities, there may be cases where such broadband signaling cannot be supported. To compensate for this, the concept of a bandwidth part (BWP) was introduced. A BWP can be defined as a continuous set of physical resource blocks (PRBs) selected from a continuous set of common resource blocks (CRBs) given a given carrier and a given numerology.

[0071] For signaling purposes, multiple BWPs can be configured, and a numerology can be configured individually for each BWP. Common resource blocks can be indexed (starting from 0) from the lowest frequency of the carrier band, and a resource grid can be defined using common resource blocks as units. The bandwidth portion can be indicated relative to the CRB with the lowest index, and the CRB with the lowest index, CRB 0, can be called point A. BWPs defined within a common resource block can be defined by the distance from point A, i.e., the offset value, and the number of physical resource blocks (PRB) occupied by the bandwidth portion.

[0072] The subcarrier spacing (SCS) refers to the frequency bandwidth occupied by a single symbol. The subcarrier spacing and symbol length are inversely proportional, and an appropriate SCS can be set depending on the channel state and the type of service provided. SCS stands for subcarrier spacing. In OFDM (orthogonal frequency division multiplex) systems, the frequency spacing of a single modulation symbol corresponds to the subcarrier spacing. A base station allocating resources can determine the FFT size based on the number of subcarriers in the bandwidth determined by the SCS. In other words, SCS is related to the FFT size.

[0073] A mixed numerology system, or multiple numerologies system, can describe a system in which multiple numerologies exist within a single carrier bandwidth. A mixed numerology system can describe a case in which, when several bandwidth parts (BWPs) exist within a single carrier bandwidth, the numerologies corresponding to each BWP (e.g., subcarrier spacing (SCS)) are different from each other.

[0074] NR aims for ultra-reliable and low-latency communications (URLLC) in data transmission. Mixed numerology is one example that can support such URLLC, as it allows for diverse numerology configurations and adaptive adjustment of symbol spacing for URLLC.

[0075] Figure 5 shows an example of a BWP configuration according to one embodiment of the present disclosure. This is only one embodiment, and the BWP configuration with symbols shown in Figure 5 does not limit the scope of the present invention. An example of a BWP configuration when the carrier bandwidth is 100 MHz is shown. There may be multiple bandwidth values ​​for the BWP (e.g., 100 MHz, 80 MHz, 50 MHz, 40 MHz, 20 MHz, 10 MHz), and the symbols may differ depending on the numerology value (e.g., 15 kHz, 30 kHz, 60 kHz).

[0076] Referring to Figure 5, a 100 MHz carrier bandwidth can consist of one or more BWPs for each symbol. The BWP configurations can be represented by symbols of the corresponding numerology with different sizes and positions. As shown in Figure 5, SSB can also have a numerology different from the numerology of the corresponding BWP, and this case can also be considered an example of mixed numerology.

[0077] For example, in the cell setup step, the DU can determine 30 kHz as the representative numerology by the management plane (M-plane). The first symbol 501 may consist of a BWP with a 30 kHz numerology and a 100 MHz bandwidth. The second symbol 503 may consist of a BWP with a 15 kHz numerology value and a 20 MHz bandwidth. The third symbol 505 may consist of a BWP with a 60 kHz numerology value and a 60 MHz bandwidth. A mixed numerology system can refer to a system in which, within a single carrier bandwidth, different numerologies are used, such as the second symbol 503 and the third symbol 505, in addition to the BWP with a representative numerology of 30 kHz, as in the first symbol 501.

[0078] For signal transmission via fronthaul based on xRAN / ORAN, a mixed numerology may be configured as in the example above. If a mixed numerology is configured, the DU needs to transmit the mixed numerology and related information to the RU. The information related to the mixed numerology may include the SCS, FFT size, CP (cyclic prefix) length, BWP size, and the BWP's position within frequency (frequency offset). In the cell configuration step, the DU can determine one numerology value as the nominal numerology. The FFT size and CP length defined by the nominal numerology can also be determined as nominal values.

[0079] Section Types are defined to define the types of messages transmitted on the control plane. Section Types can be categorized based on the message's purpose.

[0080] For example, Section type 3 can be used for messages to transmit information about PRACH and mixed numerology channels. Specifically, the information included in section type 3 is as follows:

[0081] Common Header Fields - dataDirection(data direction(gNB Tx / Rx)) field:1 bit - payloadVersion(payload version) field:3 bits - value = ”1” shall be set(1 st protocol version for payload and time reference format) - filterIndex(filter index) field:4 bits - frameId(frame identifier) ​​field:8 bits - subframeId(subframe identifier) field:4 bits - slotID(slot identifier) field:6 bits - startSymbolid(start symbol identifier) field:6 bits - numberOfsections(number of sections) field:8 bits - sectionType(section type) field:8 bits - value = ”3” shall be set - timeOffset(time offset) field:16 bits - frameStructure(frame structure) field:8 bits - cpLength(cyclic prefix length) field:16 bits - udCompHdr(user data compression header) field:8 bits - Section Fields - sectionID(section identifier) field:12 bits - rb(resource block identifier) field:1 bit - symInc(symbol number increment command) field:1 bit - startPrbc(starting PRB of data section description) field:10 bits - numPrbc(number of contiguous PRBs per data section description) field:8 bits - reMask(resource element mask) field:12 bits - numSymbol(number of symbols) field:4 bits - ef(extension flag) field:1 bit - beamId(beam identifier) ​​field:15 bits - freqOffset(frequency offset) field:24 bits - reserved(reserved for future use) field:8 bits

[0082] Section type 1 can be used to map the BF index or weight (O-RAN mandatory BF (beamforming) method) to the RE of the DL / UL channel, and specifically may include the following information:

[0083] Common Header Fields - dataDirection(data direction(gNB Tx / Rx)) field:1 bit - payloadVersion(payload version) field:3 bits - value = ”1” shall be set(1 st protocol version for payload and time reference format) - filterIndex(filter index) field:4 bits - frameId(frame identifier) ​​field:8 bits - subframeId(subframe identifier) ​​field:4 bits - slotID(slot identifier) ​​field:6 bits - startSymbolid(start symbol id) field:6 bits - numberOfsections(number of sections) field:8 bits - sectionType(section type) field:8 bits - value = ”1” shall be set - udCompHdr(user data compression header) field:8 bits - reserved(reserved for future use) field:8 bits

[0084] Section Fields - sectionId(section identifier) field:12 bits - rb(resource block identifier) field:1 bit - symInc(symbol number increment command) field:1 bit startPrbc(starting PRB of data section description) field:10 bits - numPrbc(number of contiguous PRBs per data section description) field:8 bits - reMask(resource element mask) field:12 bits - numSymbol(number of symbols) field:4 bits - ef(extension flag) field:1 bit - beamId(beam identifier) field:15 bits

[0085] Section Type 5 can be used to transmit UE scheduling information (O-RAN optional BF method) so that the RU can perform real-time BF weight calculations, and specifically can include the following information:

[0086] - Common Header Fields - dataDirection(data direction(gNB Tx / Rx)) field:1 bit - payloadVersion(payload version) field:3 bits - value = ”1” shall be set(1 st protocol version for payload and time reference format) - filterIndex(filter index) field:4 bits - frameId(frame identifier) ​​field:8 bits - subframeId(subframe identifier) ​​field:4 bits - slotID(slot identifier) ​​field:6 bits - startSymbolid(start symbol identifier) ​​field:6 bits - numberOfsections(number of sections) field:8 bits - sectionType(section type) field:8 bits - value = ”5” shall be set - udCompHdr(user data compression header) field:8 bits - reserved(reserved for future use) field:8 bits

[0087] Section Fields - sectionID(section identifier) ​​field:12 bits - rb(resource block identifier) ​​field:1 bit - symInc(symbol number increment command) field:1 bit - startPrbc(starting PRB of data section description) field:10 bits - numPrbc(number of contiguous PRBs per data section description) field:8 bits - reMask(resource element mask) field:12 bits - numSymbol(number of symbols) field:4 bits - ef(extension flag) field:1 bit -ueId(UE identifier) ​​field:15 bits

[0088] In the case of Section Type 6, it can be used to periodically transmit UE channel information (O-RAN optional BF method) so that the RU can perform real-time BF weight calculations, and specifically can include the following information:

[0089] Common Header Fields - dataDirection(data direction(gNB Tx / Rx)) field:1 bit - payloadVersion(payload version) field:3 bits - value = ”1” shall be set(1 st protocol version for payload and time reference format) - filterIndex(filter index) field:4 bits - frameId(frame identifier) field:8 bits - subframeId(subframe identifier) field:4 bits - slotID(slot identifier) field:6 bits - startSymbolid(start symbol identifier) field:6 bits - numberOfsections(number of sections) field:8 bits - sectionType(section type) field:8 bits - value = ”6” shall be set - numberOfUEs(number of UE-specific channel information data sets) field:8 bits - reserved(reserved for future use) field:8 bits

[0090] Section Fields - ef(extension flag) field:1 bit - ueId(UE identifier) field:15 bits - regularizationFactor(regularization factor used for MMSE reception) field:16 bits - reserved(reserved for future use) field:4 bits - rb(resource block identifier) ​​field:1 bit - symInc(symbol number increment command) field:1 bit - startPrbc(starting PRB of data section description) field:10 bits - numPrbc(number of contiguous PRBs per data section description) field:8 bits - ciIsample(channel information value, in-phase sample) field:16 bits - ciQsample(channel information value, quadrature sample) field:16 bits

[0091] When transmitting information to the RU via an allocation area or BWP that uses only the representative numerology predetermined in the cell setup step, the DU can transmit information to the RU via C-plane section types 1, 5, and 6. When transmitting information to the RU via an allocation area or BWP that uses numerology other than the representative numerology predetermined in the cell setup step, the DU can transmit information to the RU via section type 3, which may include values ​​associated with the other numerology, FFT size, and information associated with the position in the frequency domain. In other words, when mixed numerology is used, the DU can use C-plane section type 3 to transmit information via numerology other than the representative numerology.

[0092] However, as shown in Figure 5, the assignment information using representative numerology or the FFT size or frequency position of the BWP may be assigned differently from the previous symbol and / or slot. If the assignment information using representative numerology or the FFT size or frequency position of the BWP is assigned differently from the previous symbol and / or slot, the assignment information must be sent via C-plane section type 3. This is because the current standard includes information associated with the FFT size or frequency position (offset) of the BWP only in C-plane section type 3. In this case, C-plane section type 3 must be sent from DU to RU using a separate Ethernet message from C-plane section type 1. This is because only one type of C-plane section type can be sent via a single Ethernet message.

[0093] If assignment information using representative numerology, or if the FFT size or frequency position of a BWP is assigned differently from the previous symbol and / or slot, and the assignment information is transmitted via C-plane section type 1, it may become difficult to determine the new FFT size and frequency position of the BWP in question. Resource block (RB) information transmitted via C-plane section type 1 corresponds to information composed of physical resource blocks (PRB). Since a PRB represents the RB within a single BWP, if several BWPs exist, it may be difficult to represent the position of a BWP within the overall carrier bandwidth based solely on the PRB value.

[0094] In addition, if assignment information using representative numerology or an assignment where the FFT size or frequency position of a BWP differs from the previous symbol and / or slot, and the assignment information is transmitted in C-plane section type 5 or C-plane section type 6, it may be difficult for the RU to determine the new FFT size and frequency position of the BWP in question. C-plane section types 1 and 3 can only use beam ID-based beamforming weighting, while C-plane section types 5 and 6 can only use UE (user equipment) ID-based beamforming weighting. Since only C-plane section type 3 can transmit mixed numerology-related information as described above, if a particular RB or BWP uses UE ID-based beamforming weighting without using representative numerology, C-plane section types 5 and 6 may be unable to determine information about the RB and BWP in question (e.g., numerology, FFT size value, frequency position, CP length, etc.). In other words, in systems using mixed numerology, it is difficult for the DU to transmit information to the RU via multiple BWPs depending on the C-plane section types 5 and 6, so C-plane section type 3 must be used. However, since C-plane section type 3 only uses a beam ID-based beamforming weighting scheme, situations may arise where it is difficult for the DU to transmit UE ID-based beamforming weights and channel-related information that must be transmitted to the RU via C-plane section types 5 and 6.

[0095] As mentioned above, information related to mixed numerology is included only in section type 3. Therefore, there was a problem when it became necessary to transmit information related to mixed numerology.

[0096] For example, there may be cases where information is sent using mixed numerology when sending a message using section type 1. In this case, although the DU needs to send information related to other numerology to the RU, section type 1 does not contain information that can indicate the numerology, thus necessitating a change in section type. When the section type is changed, the DU must compose and send a new Ethernet message. In this case, the DU must, of course, compose a different form of eCPRI header and include it in the Ethernet payload frontend. As another example, there is a problem in that mixed numerology cannot be supported when sending a message using section type 5 or 6. That is, the information that can be sent by section type 5 or section type 6 (e.g., UE ID-based beamforming weighting values ​​and channel-related information related to MU-MIMO) can only be used when using only one representative numerology.

[0097] According to various embodiments of this disclosure, the overhead of separate signaling can be reduced by providing information related to mixed numerology to the RU through section extension without changing the section type of the DU. Furthermore, for MU-MIMO, it is possible to use a UE ID-based beamforming weighting scheme in systems using mixed numerology. Figures 6A to 6D illustrate various embodiments of providing information related to mixed numerology by section extension as described above.

[0098] Figures 6A to 6D illustrate examples of section extension information according to various embodiments of the present disclosure. Figures 6A to 6D show a section extension frame format for conveying mixed numerology-related information.

[0099] Referring to Figure 6, section extension information can include various types of information for constructing mixed numerology. Information for constructing mixed numerology can represent resource allocation relationships by various SCSs in the frequency domain or time domain (e.g., relationships between BWPs with different SCSs as shown in Figure 5). In one embodiment, information for constructing mixed numerology can include information associated with the frame structure. Information associated with the frame structure can include subcarrier spacing, FFT size, CP length, information for indicating the resource grid, and symbol position information.

[0100] Information for constructing a mixed numerology may include frequency information. Information associated with the above frequencies may include information indicating the position of the bandwidth, the center frequency of the BWP, the position of the BWP center frequency on the resource grid, or information associated with the frequency offset.

[0101] The information used to construct the mixed numerology may include time information. The information associated with the above frequencies may include the number of symbols in the slot to which the BWP using the mixed numerology is assigned, or the position of symbols in the slot.

[0102] Referring to Figure 6A, the information for constituting a mixed numerology according to one embodiment of the present disclosure may include extType, extLen, frameStructure, and frequencyOffset. extType can indicate the type of extension. ef indicates the extension flag, and if ef is 1, it means that other extension fields exist. extLen can indicate the length of a section extension. frameStructure can define the frame structure. It can be represented by 8 bits, the first 4 bits can indicate the magnitude of the FFT (fast fourier transform) / IFFT (inverse fast fourier transform), and the second 4 bits can indicate the subcarrier spacing and the number of slots per subframe. frequencyOffset can indicate an offset value for indicating the position of the BWP contained in the CRB.

[0103] Referring to Figure 6B, information for configuring mixed numerology according to one embodiment of the present disclosure may include extType, ef, extLen, subCarrierSpacing, fftSize, CpLength, bwpCenterFrequency, bwpSize, and symbolMap. extType may indicate the type of extension. ef may indicate the extension flag, where ef = 1 means that other extension fields exist. extLen may indicate the length of a section extension. subCarrierSpacing may indicate the subcarrier spacing value and the number of slots per subframe. fftSize may indicate the magnitude value of the FFT (fast fourier transform) / IFFT (inverse fast fourier transform). CpLength may indicate the length (duration) of the CP per symbol. bwpCenterFrequency may indicate the center frequency value of the BWP using mixed numerology. bwpSize may indicate the size of the BWP using mixed numerology. symbolMap may indicate the symbol position within a slot of the BWP using mixed numerology.

[0104] Referring to Figure 6C, the information for configuring the mixed numerology according to one embodiment of the present disclosure may include extType, ef, extLen, scsType, fftType, cpType, bwpCenter, and symbolMap. extType may indicate the type of extension. ef indicates the extension flag, where ef = 1 means that other extension fields exist. extLen may indicate the length of a section extension. scsType may be represented by 3 bits and may indicate the subcarrier interval value and the number of slots per subframe. fftType may be represented by 3 bits and may indicate the magnitude value of the FFT (fast fourier transform) / IFFT (inverse fast fourier transform). cpType may be represented by 2 bits and may indicate the duration of the CP per symbol as an index value of one of normal short CP, normal long CP, or extended CP. bwpCenter may indicate the position of the center frequency of the BWP using the mixed numerology as the RE value of the resource grid included in the CRB. The symbolMap can indicate the symbol positions within the slots of a BWP that uses mixed numerology. Of course, the bit size of each parameter in this embodiment may be larger or smaller than the values ​​expressed in this embodiment.

[0105] Referring to Figure 6D, information for configuring mixed numerology according to one embodiment of the present disclosure may include extType, extLen, frameStructure, frequencyOffset, cpLength, and symbolMap. extType can indicate the type of extension. ef indicates the extension flag, where ef = 1 means that other extension fields exist. extLen can indicate the length of a section extension. frameStructure can define the frame structure. It can be represented by 8 bits, the first 4 bits can indicate the magnitude of the FFT (fast fourier transform) / IFFT (inverse fast fourier transform), and the second 4 bits can indicate the subcarrier interval and the number of slots per subframe. frequencyOffset can indicate an offset value for indicating the position of BWPs contained in the CRB. CpLength can indicate the length (duration) of CPs per symbol. symbolMap can indicate the symbol positions within the slots of BWPs using mixed numerology.

[0106] Figures 6A to 6D described above are merely examples of information for constituting the mixed numerology of the present invention and do not limit the scope of the rights. In other words, the information for constituting the mixed numerology according to one embodiment of the present disclosure may consist of some combinations of the parameters described above.

[0107] As described above, in a fronthaul using the xRAN / ORAN standard, in a system based on mixed numerology, the DU must use section type 3 to transmit information related to other numerology systems that are not the representative numerology system. The DU can use other section types depending on the type and method of information being transmitted, and if it attempts to transmit information using a section type other than section type 3, and another numerology system that is not the representative numerology system is configured, the information related to it cannot be transmitted by that other section type. Therefore, the DU needs to define new frame formats for other section types so that they can also include information related to other numerology systems that are not the representative numerology system.

[0108] In one embodiment, the section extension format may include additional information for mixed numerology. This additional information may include parameters such as subCarrierSpacing, fftSize, CpLength, bwpCenterFrequency, bwpSize, and symbolMap.

[0109] In one embodiment, the section extension format may include additional information for mixed numerology. This additional information may include parameters such as scsType, fftType, cpType, bwpCenter, and symbolMap. In one embodiment, the section extension format may include additional information for mixed numerology. This additional information may include parameters such as frameStructure, frequencyoffset, cpLength, and symbolMap.

[0110] In one embodiment, the section extension format may include additional information for mixed numerology. This additional information may include some of the parameters described above.

[0111] In one embodiment, section extension formats may be additionally defined in sections 1, 5, and 6. By additionally defining fields for related information in sections 1, 5, and 6 to transmit information about mixed numerology, the process of separately transmitting numerology-related information by section 3 can be omitted when the DU transmits information by sections 1, 5, and 6, by transmitting the numerology-related information together with the numerology-related information. This can provide effective information transmission and reception between the DU and RU by omitting unnecessary signaling.

[0112] For example, if the DU uses a beamforming scheme that utilizes UE IDs, the DU can send control messages to the RU via section type 5. In this case, if the control message sent via section type 5 includes other numerologies that are not representative numerologies, information related to these other numerologies may be sent to the RU along with the UE ID.

[0113] As another example, when a DU wants to send channel status and related information to a RU, it can send a control message to the RU using section type 6. In this case, if a numerology other than the representative numerology is configured in the control message sent by section type 6, information related to the above other numerology may be sent along with the channel status (ciIsample, ciQsample).

[0114] Figure 7 shows an example of a connection between a DU and an RU according to one embodiment of the present disclosure. A DU can be connected to various RUs. Each RU may have different characteristics, performance, and capabilities.

[0115] Referring to Figure 7, a DU can be connected to multiple RUs. In this case, the RUs can be referred to as O-RUs according to the O-RAN standard. A DU can be connected to X O-RUs. A DU can be connected to O-RU #0, O-RU #1, O-RU #2, ..., up to O-RU #X-1.

[0116] In one embodiment, some of the O-RUs can receive control messages containing extended section fields set by the DU. In another embodiment, some of the O-RUs can receive some of the parameters (subCarrierSpacing, fftSize, CpLength, bwpCenterFrequency, bwpSize, symbolMap or scsType, fftType, cpType, bwpCenter, symbolMap or frameStructure, frequencyoffset, cpLength, symbolMap) or parameters associated with them as information contained in the extended section fields. In yet another embodiment, other parts of the O-RUs can receive some of the parameters or parameters associated with them that are different from those received by the O-RUs described above. In yet another embodiment, other parts of the O-RUs can receive all of the parameters. The DU can set each RU with parameters of the control plane.

[0117] While the present invention describes a DU for configuring mixed numerology and an RU for configuring resource allocation or a resource grid by mixed numerology, it can be understood that a structure in which the DU of this disclosure is connected to RUs that do not support mixed numerology is also an embodiment of this disclosure. That is, in one embodiment, some of the O-RUs may also receive control messages that do not include the extended section fields for mixed numerology as in the conventional. It can also be understood that a DU identifying RUs that do not support mixed numerology and configuring the corresponding control messages is also an embodiment of this disclosure.

[0118] According to one embodiment of the present disclosure, the operation method of a digital unit (DU) in a wireless communication system includes the steps of setting a section extension field containing additional information and transmitting a first control message containing the section extension field to a radio unit (RU) via a fronthaul interface, the first control message may be used to schedule a terminal on the control plane.

[0119] In one embodiment, the additional information may include parameters indicating mixed-numerology-related information.

[0120] In one embodiment, the method further includes the steps of setting the section extension field to include a parameter representing the mixed numerology-related information, and transmitting a first control message including the section extension field including the parameter representing the mixed numerology-related information, wherein the first control message including the section extension field including the parameter representing the mixed numerology-related information may be used on the control plane to schedule terminals.

[0121] In one embodiment, the first control message corresponds to the control messages of Section Types 1, 5, and 6 of the O-RAN (open-radio access network), and the first control message may include scheduling information for the terminal.

[0122] In one embodiment, the above parameter may include at least one of the following: subcarrier spacing (SCS) of the BWP constituting the mixed numerology, the size of the FFT (fast Fourier transform), the length of the CP, the center frequency of the BWP, the size of the BWP, and the symbol map.

[0123] In one embodiment, the above parameter may include at least one of the subcarrier spacing (SCS), fast Fourier transform (FFT) size, CP length, symbol map, and center frequency position of the BWP constituting the mixed numerology.

[0124] In one embodiment, the above parameter may include at least one of the subcarrier spacing (SCS), fast Fourier transform (FFT) size, CP length, symbol map, and frequency offset value of the BWP constituting the mixed numerology.

[0125] According to one embodiment of the present disclosure, the operation method of a radio unit (RU) in a wireless communication system includes the process of receiving a first control message from a digital unit (DU) via a fronthaul interface, the section extension field including additional information, the section extension field being set by the DU, and the first control message being used to schedule a terminal on a control plane.

[0126] In one embodiment, the additional information may include parameters indicating mixed-numerology-related information.

[0127] In one embodiment, the process further includes receiving a first control message which includes a section extension field which includes a parameter that represents mixed numerology-related information, wherein the section extension field is configured to include a parameter that represents the mixed numerology-related information, and the first control message which includes a section extension field which includes a parameter that represents the mixed numerology-related information may be used to schedule a terminal on the control plane.

[0128] In one embodiment, the first control message corresponds to the control messages of Section Types 1, 5, and 6 of the O-RAN (open-radio access network), and the first control message may include scheduling information for the terminal.

[0129] In one embodiment, the above parameter may include at least one of the following: subcarrier spacing (SCS) of the BWP constituting the mixed numerology, the size of the FFT (fast Fourier transform), the length of the CP, the center frequency of the BWP, the size of the BWP, and the symbol map.

[0130] In one embodiment, the above parameter may include at least one of the subcarrier spacing (SCS), fast Fourier transform (FFT) size, CP length, symbol map, and center frequency position of the BWP constituting the mixed numerology.

[0131] In one embodiment, the above parameter may include at least one of the subcarrier spacing (SCS), fast Fourier transform (FFT) size, CP length, symbol map, and frequency offset value of the BWP constituting the mixed numerology.

[0132] According to one embodiment of the present disclosure, a digital unit (DU) device in a wireless communication system includes a transceiver and at least one processor, the at least one processor configured to set a section extension field containing additional information and to transmit a first control message containing the section extension field to a radio unit (RU) via a fronthaul interface, the first control message may be used to schedule a terminal on a control plane.

[0133] In one embodiment, the additional information may include parameters indicating mixed-numerology-related information.

[0134] In one embodiment, the at least one processor is configured to set the section extension field to include a parameter representing the mixed numerology-related information, and to transmit a first control message including the section extension field including the parameter representing the mixed numerology-related information, the first control message including the section extension field including the parameter representing the mixed numerology-related information may be used in the control plane to schedule terminals.

[0135] In one embodiment, the first control message corresponds to the control messages of Section Types 1, 5, and 6 of the O-RAN (open-radio access network), and the first control message may include scheduling information for the terminal.

[0136] In one embodiment, the above parameter may include at least one of the following: subcarrier spacing (SCS) of the BWP constituting the mixed numerology, the size of the FFT (fast Fourier transform), the length of the CP, the center frequency of the BWP, the size of the BWP, and the symbol map.

[0137] In one embodiment, the above parameter may include at least one of the subcarrier spacing (SCS), fast Fourier transform (FFT) size, CP length, BWP center frequency position, and symbol map of the BWP constituting the mixed numerology.

[0138] In one embodiment, the above parameters may include at least one of the subcarrier spacing (SCS), fast Fourier transform (FFT) size, CP length and frequency offset value, and symbol map of the BWP constituting the mixed numerology.

[0139] According to one embodiment of the present disclosure, a radio unit (RU) in a wireless communication system includes a transceiver and at least one processor, the at least one processor configured to receive a first control message from a digital unit (DU) via a fronthaul interface, the section extension field including additional information, the section extension field being set by the DU, and the first control message being used to schedule a terminal on a control plane.

[0140] In one embodiment, the additional information may include parameters indicating mixed-numerology-related information.

[0141] In one embodiment, the at least one processor is further configured to receive a first control message comprising a section extension field comprising parameters representing mixed numerology-related information, wherein the section extension field is set to include parameters representing the mixed numerology-related information, and the first control message comprising the section extension field comprising parameters representing the mixed numerology-related information may be used to schedule a terminal on the control plane.

[0142] In one embodiment, the first control message corresponds to the control messages of Section Types 1, 5, and 6 of the O-RAN (open-radio access network), and the first control message may include scheduling information for the terminal.

[0143] In one embodiment, the above parameter may include at least one of the following: subcarrier spacing (SCS) of the BWP constituting the mixed numerology, the size of the FFT (fast Fourier transform), the length of the CP, the center frequency of the BWP, the size of the BWP, and the symbol map.

[0144] In one embodiment, the above parameter may include at least one of the subcarrier spacing (SCS), fast Fourier transform (FFT) size, CP length, BWP center frequency position, and symbol map of the BWP constituting the mixed numerology.

[0145] In one embodiment, the above parameter may include at least one of the subcarrier spacing (SCS), fast Fourier transform (FFT) size, CP length, symbol map, and frequency offset value of the BWP constituting the mixed numerology.

Claims

1. A method performed by a distributed unit (DU) in a wireless communication system, The process includes transmitting a control message containing information about mixed numerology to a radio unit (RU), The information relating to the mixed numerology includes information relating to the frame structure, information relating to the frequency offset, and information relating to the length of the CP (cyclo prefix). The type of the control message is a method that includes a section type 5 relating to UE (user equipment) scheduling information or a section type 6 relating to channel information.

2. The information regarding the frame structure consists of 8 bits. The first four bits of the aforementioned eight bits represent the size of the FFT (fast fourer transform) / IFFT (inverse fast fourer transform). The method according to claim 1, wherein the second 4 bits of the 8 bits indicate the subcarrier spacing.

3. The method according to claim 1 or 2, wherein the information relating to the length of the CP indicates the length of the CP per symbol.

4. The method according to any one of claims 1 to 3, wherein the control message is a message for identifying beamforming.

5. The control message further includes an extension flag (ef), an extension type (extType), and an extension length (extLen), The aforementioned extension flag includes 1 bit, The method according to any one of claims 1 to 4, wherein the extension type indicates that the section extension of the control message is related to mixed numerology.

6. A method performed by a radio unit (RU) in a wireless communication system, The process includes receiving a control message from a distributed unit (DU) containing information about mixed numerology, The information relating to the mixed numerology includes information relating to the frame structure, information relating to the frequency offset, and information relating to the length of the CP (cyclo prefix). The type of the control message is a method that includes a section type 5 relating to UE (user equipment) scheduling information or a section type 6 relating to channel information.

7. The information regarding the frame structure consists of 8 bits. The first four bits of the aforementioned eight bits represent the size of the FFT (fast fourer transform) / IFFT (inverse fast fourer transform). The method according to claim 6, wherein the second four bits of the eight bits indicate the subcarrier spacing.

8. The method according to claim 6 or 7, wherein the information relating to the length of the CP is the length of the CP per symbol.

9. The method according to any one of claims 6 to 8, wherein the control message is a message for identifying beamforming.

10. The control message further includes an extension flag (ef), an extension type (extType), and an extension length (extLen), The aforementioned extension flag includes 1 bit, The method according to any one of claims 6 to 9, wherein the extension type indicates that the section extension of the control message is related to mixed numerology.

11. A distributed unit (DU) of a wireless communication system, At least one transceiver, and It includes at least one processor operably connected to the at least one transceiver, The at least one processor is configured to perform the method described in any one of claims 1 to 5.

12. A radio unit (RU) of a wireless communication system, At least one transceiver, and It includes at least one processor operably connected to the at least one transceiver, The at least one processor is configured to perform the method described in any one of claims 6 to 10.

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