KR20240026806A - Electronic device and method for indicating non-scheduling layer in fronthaul interface - Google Patents

Abstract

In embodiments, an electronic device of a radio unit (RU) includes at least one fronthaul transceiver, at least one radio frequency (RF) transceiver, and a combination of the at least one fronthaul transceiver and the at least one RF transceiver. It may include at least one processor. The at least one processor is a control plane (C-plane) including information about the resource area and UE (user equipment) identification information corresponding to a value indicating non-scheduling of the layer. ) may be configured to receive a message from a distributed unit (DU) through a fronthaul interface. The at least one processor may be configured to calculate a beamforming weight based on the C-plane message. The at least one processor may be configured to perform beamforming based on the beamforming weight.

Description

Electronic device and method for indicating non-scheduling layer in fronthaul interface {ELECTRONIC DEVICE AND METHOD FOR INDICATING NON-SCHEDULING LAYER IN FRONTHAUL INTERFACE}

This disclosure relates to a fronthaul interface. More specifically, the present disclosure relates to an electronic device and method for indicating a non-scheduling layer in a fronthaul interface.

As transmission capacity increases in wireless communication systems, function split, which functionally separates base stations, is being applied. Depending on the separation of functions, the base station can be divided into a distributed unit (DU) and a radio unit (RU). A fronthaul interface is defined for communication between DUs and RUs.

In embodiments, an electronic device of a radio unit (RU) includes at least one fronthaul transceiver, at least one radio frequency (RF) transceiver, and a combination of the at least one fronthaul transceiver and the at least one RF transceiver. It may include at least one processor. The at least one processor is a control plane (C-plane) including information about the resource area and UE (user equipment) identification information corresponding to a value indicating non-scheduling of the layer. ) may be configured to receive a message from a distributed unit (DU) through a fronthaul interface. The at least one processor may be configured to calculate a beamforming weight based on the C-plane message. The at least one processor may be configured to perform beamforming based on the beamforming weight.

In embodiments, 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 identify non-scheduling for a layer in the resource area. The at least one processor sends a control plane (C-plane) message including information about the resource area and UE (user equipment) identification information corresponding to a value indicating the non-scheduling of the layer. Can be configured to generate. The at least one processor may be configured to transmit the generated C-plane message to a radio unit (RU). The C-plane message may be related to beamforming weight in the RU.

In embodiments, a method performed by a radio unit (RU) includes information on a resource area and user equipment (UE) identification information corresponding to a value indicating non-scheduling of the layer. It may include an operation of receiving a control plane (C-plane) message from a distributed unit (DU) through a fronthaul interface. The method may include calculating a beamforming weight based on the C-plane message. The method may include performing beamforming based on the beamforming weight.

In embodiments, a method performed by a distributed unit (DU) may include identifying non-scheduling for a layer in a resource area. The method includes generating a control plane (C-plane) message including information about the resource area and UE (user equipment) identification information corresponding to a value indicating the non-scheduling of the layer. may include. The method may include transmitting the generated C-plane message to a radio unit (RU). The C-plane message may be related to beamforming weight in the RU.

1 shows a wireless communication system according to embodiments.
2A shows a fronthaul interface according to embodiments.
FIG. 2B illustrates a fronthaul interface of an open (O)-radio access network (RAN) according to embodiments.
FIG. 3A shows components of a distributed unit (DU) according to embodiments.
FIG. 3B shows components of a radio unit (RU) according to embodiments.
Figure 4 shows an example of function split between DU and RU, according to embodiments.
Figure 5A shows examples of downlink (DL) messages according to embodiments.
FIG. 5B shows examples of uplink (UL) messages according to embodiments.
Figure 6 shows an example of resource allocation for each layer according to one embodiment.
FIGS. 7A and 7B illustrate an example of beamforming using an indication of a non-scheduling layer according to an embodiment.
Figure 8 shows an example of beamforming weight for each resource area according to an embodiment.
FIG. 9 illustrates the functional configuration of a DU and a RU for beamforming using instructions from a non-scheduling layer according to an embodiment.
Figure 10 shows the operation flow of a DU for indicating a non-scheduling layer according to an embodiment.
Figure 11 shows the operation flow of an RU for indicating a non-scheduling layer according to an embodiment.
Figures 12A and 12B show examples of C-plane messages for indicating a non-scheduling layer according to one embodiment.

Terms used in the present disclosure are merely used to describe specific embodiments and may not be intended to limit the scope of other embodiments. Singular expressions may include plural expressions, unless the context clearly indicates otherwise. Terms used herein, including technical or scientific terms, may have the same meaning as generally understood by a person of ordinary skill in the technical field described in this disclosure. Among the terms used in this disclosure, terms defined in general dictionaries may be interpreted to have the same or similar meaning as the meaning they have in the context of related technology, and unless clearly defined in this disclosure, have an ideal or excessively formal meaning. It is not interpreted as In some cases, even terms defined in the present disclosure cannot be interpreted to exclude embodiments of the present disclosure.

In various embodiments of the present disclosure described below, a hardware approach method is explained as an example. However, since various embodiments of the present disclosure include technology using both hardware and software, the various embodiments of the present disclosure do not exclude software-based approaches.

Terms referring to signals used in the following description (e.g., packet, message, signal, information, signaling), terms referring to resources (e.g., section, symbol, slot, subframe ( subframe, radio frame, subcarrier, resource element (RE), resource block (RB), bandwidth part (BWP), opportunity), terminology for computational states (e.g. phase ( step, operation, procedure), terms referring to data (e.g. packet, message, user stream, information, bit, symbol, codeword) , a term referring to a channel, a term referring to network entities (distributed unit (DU), radio unit (RU), central unit (CU), control plane (CU-CP), user plane (CU-UP) ), O-DU (O-RAN (open radio access network) DU), O-RU (O-RAN RU), O-CU (O-RAN CU), O-CU-UP (O-RAN CU-CP ), O-CU-CP (O-RAN CU-CP)), terms referring to device components, etc. are examples for convenience of explanation. Accordingly, the present disclosure is not limited to the terms described below, and other terms having equivalent technical meaning may be used. In addition, terms such as '... part', '... base', '... water', and '... body' used hereinafter mean at least one shape structure or a unit that processes a function. It can mean.

In addition, in the present disclosure, the expressions greater than or less than may be used to determine whether a specific condition is satisfied or fulfilled, but this is only a description for expressing an example, and the description of more or less may be used. It's not exclusion. Conditions written as ‘more than’ can be replaced with ‘more than’, conditions written as ‘less than’ can be replaced with ‘less than’, and conditions written as ‘more than and less than’ can be replaced with ‘greater than and less than’. In addition, hereinafter, 'A' to 'B' means at least one of the elements from A to (including A) and B (including B).

The present disclosure describes various embodiments using terms used in some communication standards (e.g., 3rd Generation Partnership Project (3GPP), extensible radio access network (xRAN), and open-radio access network (O-RAN)), This is only an example for explanation, and various embodiments of the present disclosure can be easily modified and applied to other communication systems.

1 shows a wireless communication system according to embodiments.

Referring to FIG. 1, FIG. 1 illustrates a base station 110 and a terminal 120 as some of the nodes that use a wireless channel in a wireless communication system. Although FIG. 1 shows only one base station, the wireless communication system may further include other base stations that are the same or similar to base station 110.

The base station 110 is a network infrastructure that provides wireless access to the terminal 120. The base station 110 has coverage defined based on the distance at which signals can be transmitted. In addition to the base station, the base station 110 includes 'access point (AP)', 'eNodeB (eNB)', '5G node (5th generation node)', and 'next generation nodeB'. , gNB)', 'wireless point', 'transmission/reception point (TRP)', or other terms with equivalent technical meaning.

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

The terminal 120 includes 'user equipment (UE)', 'customer premises equipment (CPE)', 'mobile station', and 'subscriber station' in addition to the terminal. , may be referred to as a ‘remote terminal’, a ‘wireless terminal’, an electronic device’, or a ‘user device’ or other terms with equivalent technical meaning. .

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

A first antenna port and a second antenna port are said to be in a QCL relationship if the large-scale characteristics of the channel carrying the symbols on the first antenna port can be inferred from the channel carrying the symbols on the second antenna port. can be evaluated. For example, a wide range of characteristics include delay spread, doppler spread, doppler shift, average gain, average delay, and spatial receiver parameters. It may include at least one of:

In FIG. 1, both the base station 110 and the terminal 120 are depicted as performing beamforming, but embodiments of the present disclosure are not necessarily limited thereto. In some embodiments, the terminal may or may not perform beamforming. Additionally, the base station may or may not perform beamforming. That is, only one of the base station and the terminal may perform beamforming, or neither the base station nor the terminal may perform beamforming.

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

Conventionally, in a communication system where the cell radius of the base station is relatively large, each base station has a digital processing unit (or distributed unit (DU)) and a radio frequency (RF) processing unit (RF processing unit, or RU). It was installed to include the functions of a radio unit). However, as higher frequency bands are used in 4G (4 ^th generation) and/or subsequent communication systems (e.g., 5G) and cell coverage of base stations becomes smaller, the number of base stations to cover a specific area has increased. The installation cost burden on operators to install base stations has also increased. In order to minimize the installation cost of the base station, the DU and RU of the base station are separated, one or more RUs are connected to one DU through a wired network, and one or more RUs are deployed geographically distributed to cover a specific area. A structure has been proposed. Hereinafter, the deployment structure and expansion examples of the base station according to various embodiments of the present disclosure are described through FIGS. 2A and 2B.

2A shows a fronthaul interface according to embodiments. Fronthaul refers to the connection between entities between the wireless LAN and the base station, unlike backhaul between the base station and the core network. FIG. 2A shows an example of a fronthaul structure between a DU 210 and one RU 220, but this is only for convenience of explanation and the present disclosure is not limited thereto. In other words, the embodiment of the present disclosure can also be applied to the fronthaul structure between one DU and multiple RUs. For example, embodiments of the present disclosure can be applied to a fronthaul structure between one DU and two RUs. Additionally, embodiments of the present disclosure can also be applied to a fronthaul structure between one DU and three RUs.

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

As communication technology develops, mobile data traffic increases, and accordingly, the bandwidth requirement for the fronthaul between digital units and wireless units has increased significantly. In deployments such as C-RAN (centralized/cloud radio access network), DU performs functions for PDCP (packet data convergence protocol), RLC (radio link control), MAC (media access control), and PHY (physical). , the RU may be implemented to perform more functions for the PHY layer in addition to the radio frequency (RF) function.

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

The RU 220 may be responsible for lower layer functions of the wireless network. For example, the RU 220 may perform part of the PHY layer and RF functions. Here, the part of the PHY layer is one that is performed at a relatively lower level than the DU 210 among the functions of the PHY layer, for example, iFFT conversion (or FFT conversion), CP insertion (CP removal), and digital beamforming. It can be included. An example of this specific functional separation is detailed in Figure 4. RU 220 is 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. According to one embodiment, if the RU 220 complies with the O-RAN standard, it may be referred to as an O-RAN RU (O-RU). The RU 220 may be replaced with a second network entity for a base station (eg, gNB) in embodiments of the present disclosure, if necessary.

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

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

FIG. 2B illustrates a fronthaul interface of an open (O)-radio access network (RAN) according to embodiments. As a base station 110 according to distributed deployment, an eNB or gNB is exemplified.

Referring to FIG. 2B, the base station 110 may include an O-DU 251 and O-RUs 253-1, ..., 253-n. Hereinafter, for convenience of explanation, the operations and functions of the O-RU 253-1 may be understood as explanations for each of other O-RUs (eg, O-RU 253-n).

The O-DU 251 includes functions excluding functions exclusively assigned to the O-RU 253-1 among the functions of the base station (e.g., eNB, gNB) according to FIG. 4, which will be described later. It is a logical node that does. O-DU (251) can control the operation of O-RUs (253-1, ..., 253-n). The O-DU 251 may be referred to as a lower layer split (LLS) central unit (CU). The O-RU 253-1 is a logical node that includes a subset of the functions of a base station (e.g., eNB, gNB) according to FIG. 4, which will be described later. Real-time aspects of control plane (C-plane) communication and user plane (U-plane) communication with the O-RU 253-1 may be controlled by the O-DU 251.

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

In FIG. 2B, to explain O-RAN, the entities of the base station 110 are referred to as O-DU and O-RU. However, these names should not be construed as limiting the embodiments of the present disclosure. In the embodiments described through FIGS. 3A to 12B, it goes without saying that the operations of the DU 210 can be performed by the O-DU 251. The description of DU 210 may be applied to O-DU 251. Likewise, in the embodiments described through FIGS. 3A to 12B, of course, the operations of the RU 220 may be performed by the O-RU 253-1. The description of RU 220 may be applied to O-RU 253-1.

FIG. 3A shows components of a distributed unit (DU) according to embodiments. The configuration illustrated in FIG. 3A may be understood as the configuration of DU 210 in FIG. 2A (or O-DU 250 in FIG. 2B) as part of a base station. Terms such as '... unit' and '... unit' used hereinafter refer to a unit that processes at least one function or operation, which can be implemented through hardware, software, or a combination of hardware and software. there is.

Referring to FIG. 3A, the DU 210 includes a transceiver 310, a memory 320, and a processor 330.

The transceiver 310 may perform functions for transmitting and receiving signals in a wired communication environment. The transceiver 310 may include a wired interface for controlling direct connection between devices through a transmission medium (e.g., copper wire, optical fiber). For example, the transceiver 310 may transmit 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 unit (RU) through the transceiver 310. The DU 210 may be connected to a CU in a core network or distributed arrangement through the transceiver 310.

The transceiver 310 may perform functions for transmitting 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, when transmitting data, the transceiver 310 generates complex symbols by encoding and modulating the transmission bit stream. Additionally, when receiving data, the transceiver 310 restores the received bit stream by demodulating and decoding the baseband signal. Additionally, the transceiver 310 may include multiple transmission and reception paths. Additionally, according to one embodiment, the transceiver 310 may be connected to the core network or other nodes (eg, integrated access backhaul (IAB)).

The transceiver 310 can transmit and receive signals. For example, the transceiver 310 may transmit a management plane (M-plane) message. For example, the transceiver 310 may transmit a synchronization plane (management plane, S-plane) message. For example, the transceiver 310 may transmit a control plane (C-plane) message. For example, the transceiver 310 may transmit a user plane (U-plane) message. For example, transceiver 310 may receive a user plane message. Although only the transceiver 310 is shown in FIG. 3A, according to another implementation example, the DU 210 may include two or more transceivers.

The transceiver 310 transmits and receives signals as described above. Accordingly, all or part of the transceiver 310 may be referred to as a 'communication unit', a 'transmission unit', a 'reception unit', or a 'transmission/reception unit'. Additionally, in the following description, transmission and reception performed through a wireless channel are used to mean that processing as described above is performed by the transceiver 310.

Although not shown in FIG. 3A, the transceiver 310 may further include a backhaul transceiver for connection to the core network or another base station. The backhaul transceiver provides an interface to communicate with other nodes in the network. In other words, the backhaul transceiver converts the bit string transmitted from the base station to other nodes (e.g., other access nodes, other base stations, upper nodes, core networks, etc.) into physical signals, and the physical signals received from other nodes into bit strings. Convert.

The memory 320 stores data such as basic programs, application programs, and setting information for operation of the DU 210. Memory 320 may be referred to as a storage unit. The memory 320 may be comprised of volatile memory, non-volatile memory, or a combination of volatile memory and non-volatile memory. And, the memory 320 provides stored data according to the request of the processor 330.

The processor 330 controls the overall operations of the DU (210). The processor 380 may be referred to as a control unit. For example, the processor 330 transmits and receives signals through the transceiver 310 (or through the backhaul communication unit). Additionally, the processor 330 writes and reads data into the memory 320. Additionally, the processor 330 can perform protocol stack functions required by communication standards. Although only the processor 330 is shown in FIG. 3A, according to another implementation example, the DU 210 may include two or more processors.

The configuration of the DU 210 shown in FIG. 3A is only an example, and the example of the DU performing the embodiments of the present disclosure is not limited to the configuration shown in FIG. 3A. In some embodiments, some configurations may be added, deleted, or changed.

FIG. 3B shows components of a radio unit (RU) according to embodiments. The configuration illustrated in FIG. 3B may be understood as a configuration of the RU 220 of FIG. 2B or the O-RU 253-1 of FIG. 2B as part of a base station. Terms such as '... unit' and '... unit' used hereinafter refer to a unit that processes at least one function or operation, which can be implemented through hardware, software, or a combination of hardware and software. there is.

Referring to FIG. 3B, the RU 220 includes an RF transceiver 360, a fronthaul transceiver 365, a memory 370, and a processor 380.

The RF transceiver 360 performs functions for transmitting and receiving signals through a wireless channel. For example, the RF transceiver 360 upconverts the baseband signal into an RF band signal and transmits it through an antenna, and downconverts 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, etc.

The RF transceiver 360 may include multiple transmission and reception paths. Furthermore, the RF transceiver 360 may include an antenna unit. The RF transceiver 360 may include at least one antenna array comprised of multiple antenna elements. In terms of hardware, the RF transceiver 360 may be composed of digital circuits and analog circuits (eg, radio frequency integrated circuit (RFIC)). Here, the digital circuit and analog circuit can be implemented in one package. Additionally, the RF transceiver 360 may include multiple RF chains. The RF transceiver 360 may perform beamforming. The RF transceiver 360 may apply a beamforming weight to the signal to be transmitted and received in order to give directionality according to the settings of the processor 380. According to one embodiment, the RF transceiver 360 may include a radio frequency (RF) block (or RF unit).

According to one embodiment, the RF transceiver 360 may transmit and receive signals on a radio access network. For example, the RF transceiver 360 may transmit a downlink signal. Downlink signals include synchronization signal (SS), reference signal (RS) (e.g., cell-specific reference signal (CRS), demodulation (DM)-RS), system information (e.g., MIB, SIB, It may include remaining system information (RMSI), other system information (OSI), configuration message, control information, or downlink data. Also, for example, the RF transceiver 360 may receive an uplink signal. Uplink signals include random access-related signals (e.g., random access preamble (RAP) (or Msg1 (message 1)), Msg3 (message 3)), reference signals (e.g., sounding reference signal (SRS), DM) -RS), or power headroom report (PHR), etc. Although only the RF transceiver 360 is shown in FIG. 3B, according to another implementation example, the RU 220 may include two or more RF transceivers.

According to embodiments, RF transceiver 460 may transmit RIM-RS. The RF transceiver 460 may transmit a first type of RIM-RS (eg, RIM-RS type 1 of 3GPP) to notify detection of remote interference. The RF transceiver 460 may transmit a second type of RIM-RS (e.g., RIM-RS type 2 of 3GPP) to indicate the presence or absence of remote interference.

The fronthaul transceiver 365 can transmit and receive signals. According to one embodiment, the fronthaul transceiver 365 may transmit 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 (management 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 transmit a user plane (U-plane) message. For example, fronthaul transceiver 365 may receive user plane messages. Although only the fronthaul transceiver 365 is shown in FIG. 3B, according to another implementation example, the RU 220 may include two or more fronthaul transceivers.

The RF transceiver 360 and the fronthaul transceiver 365 transmit and receive signals as described above. Accordingly, all or part of the RF transceiver 360 and the fronthaul transceiver 365 may be referred to as a 'communication unit', a 'transmission unit', a 'reception unit', or a 'transceiver unit'. Additionally, in the following description, transmission and reception performed through a wireless channel are used to mean that the processing as described above is performed by the RF transceiver 360. In the following description, transmission and reception performed through a wireless channel are used to mean that the processing as described above is performed by the RF transceiver 360.

The memory 370 stores data such as basic programs, application programs, and setting information for operation of the RU 220. Memory 370 may be referred to as a storage unit. The memory 370 may be comprised of volatile memory, non-volatile memory, or a combination of volatile memory and non-volatile memory. And, the memory 370 provides stored data according to the request of the processor 380. According to one embodiment, memory 370 may include memory for conditions, commands, or setting values related to the SRS transmission method.

The processor 380 controls the overall operations of the RU (220). The processor 380 may be referred to as a control unit. For example, processor 380 transmits and receives signals through RF transceiver 360 or fronthaul transceiver 365. Additionally, the processor 380 writes and reads data into the memory 370. Additionally, the processor 380 can perform protocol stack functions required by communication standards. Although only the processor 380 is shown in FIG. 3B, according to another implementation example, the RU 220 may include two or more processors. The processor 380 is a set of instructions or code stored in the memory 370, which is a storage space that stores instructions/code or instructions/code that are at least temporarily residing in the processor 380, or the processor 380 It may be part of the circuitry that constitutes. Additionally, the processor 380 may include various modules for performing communication. The processor 380 may control the RU 220 to perform operations according to embodiments described later.

The configuration of the RU 220 shown in FIG. 3B is only an example, and the example of the RU that performs the embodiments of the present disclosure is not limited to the configuration shown in FIG. 3B. In some embodiments, some configurations may be added, deleted, or changed.

Figure 4 shows an example of function split between DU and RU, according to embodiments. As wireless communication technology develops (e.g., the introduction of ^{the 5th} generation (5G) communication system (or the introduction of the new radio (NR) communication system), the frequency bands used have further increased. As the cell radius of the base station becomes very small, The number of RUs required to be installed has further increased. Additionally, in the 5G communication system, the amount of data transmitted has increased by more than 10 times, and the transmission capacity of the wired network transmitted through the fronthaul has increased significantly. Factors mentioned above In the 5G communication system, the installation cost of the wired network can increase significantly. Therefore, in order to lower the transmission capacity of the wired network and reduce the installation cost of the wired network, some functions of the DU's modem are installed. 'Function split', which lowers the fronthaul transmission capacity by transferring it to the RU, can be used.

To reduce the burden on the DU, the role of the RU, which is responsible only for existing RF functions, can be expanded to include some functions of the physical layer. As the RU performs higher layer functions, the throughput of the RU increases, thereby increasing the transmission bandwidth in the fronthaul, and at the same time, the latency requirement constraints due to response processing can be lowered. Meanwhile, as the RU performs higher layer functions, the virtualization gain decreases, and the size, weight, and cost of the RU increase. Considering the trade-off of the advantages and disadvantages described above, it is necessary to implement optimal functional separation.

Referring to Figure 4, functional separations in the physical layer below the MAC layer are shown. In the case of downlink (DL), which transmits signals to the terminal through a wireless network, the base station sequentially performs channel encoding/scrambling, modulation, layer mapping, antenna mapping, RE mapping, digital beamforming (e.g. precoding), iFFT conversion/CP insertion, and RF conversion can be performed. In the case of uplink (UL), which receives signals from a terminal through a wireless network, the base station sequentially performs RF conversion, FFT conversion/CP removal, digital beamforming (pre-combining), and RE decoding. It can perform mapping, channel estimation, layer demapping, demodulation, and decoding/descrambling. Separation of uplink functions and downlink functions can be defined in various types depending on the need between vendors (vendors), discussions on specifications, etc. according to the trade-off described above.

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

According to one embodiment, when large-capacity signal processing is expected, such as FR 1 MMU, function separation at a relatively high layer (e.g., fourth function separation 420b) may be required to reduce fronthaul capacity. . In addition, separation of functions at too high a layer (e.g., the sixth function separation 430) may cause a burden on the implementation of the RU due to the complicated control interface and the inclusion of multiple PHY processing blocks within the RU. Appropriate separation of functions may be required depending on the arrangement and implementation method of the and RU.

According to one embodiment, when precoding of data received from the DU cannot be processed (i.e., when there is a limit to the precoding capability of the RU), the third function separation 420a or a lower function is performed. Separation (e.g., second functional separation 410) may be applied. Conversely, if there is a capability to process precoding of data received from the DU, the fourth functional separation 420b or a higher functional separation (e.g., the sixth functional separation 430) may be applied.

Hereinafter, in the present disclosure, unless otherwise specified, the embodiments include the third function separation 420a (which may be referred to as category A, CAT-A) or the fourth function separation 420a for performing beamforming processing in the RU. It is described based on functional separation 420b (which may be referred to as category B CAT-B). The O-RAN standard distinguishes between types of O-RUs depending on whether the precoding function is located on the interface of the O-DU or the O-RU interface. An O-RU in which precoding is not performed (i.e., low complexity) may be referred to as a CAT-A O-RU. The O-RU where precoding is performed may be referred to as a CAT-B O-RU.

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, sub-PHY refers to physical layer processing processed in the RU of the fronthaul interface. For example, the sub-PHY may include FFT/iFFT, digital beamforming, physical random access channel (PRACH) extraction and filtering. However, the above-described criteria do not exclude embodiments with other functional separations. The functional configuration, signaling or operation of FIGS. 5A to 12B described later may be applied not only to the third functional separation 420a or fourth functional separation 420b but also to other functional separations.

Embodiments of the present disclosure illustrate the specifications of eCPRI and O-RAN as fronthaul interfaces when transmitting messages between a DU (e.g., DU 210 in FIG. 2A) and RU (e.g., RU 220 in FIG. 2A). It is described negatively. The Ethernet payload of the message may include an eCPRI header, an O-RAN header, and additional fields. Hereinafter, various embodiments of the present disclosure will be described using the standard terms of eCPRI or O-RAN, but other expressions having equivalent meaning to each term may be used instead of the various embodiments of the present disclosure.

Fronthaul's transport protocol can be Ethernet and eCPRI, which are easy to share with networks. The eCPRI header and O-RAN header may be included in the Ethernet payload. The eCPRI header can be located in front of the Ethernet payload. The contents of the eCPRI header are as follows.

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

2) ecpriReserved (3 bits): This parameter is reserved for future use of eCPRI.

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

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

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

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

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

The eAxC identifier (ID) is 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'). Includes. Bit allocation of eAxC ID can be divided as follows.

1) DU_port ID: To distinguish processing units in O-DU, DU_port ID is used (e.g. different baseband cards). It is expected that the O-DU allocates bits for the DU_port ID and the O-RU attaches the same value to the UL U-plane message carrying the same sectionId data.

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

3) CC_ID: CC_ID distinguishes carrier components supported by O-RU.

4) RU_port ID: RU_port ID specifies logical flows such as data layer or spatial stream, and signal channels that require separate numerologies (e.g. PRACH) or special antenna allocation such as SRS. do.

The fronthaul application protocol is the control plane (C-plane), user plane (U-plane), synchronization plane (S-plane), and management plane (M). -plane) may be included.

The control plane may be configured to provide scheduling information and beamforming information through control messages. The control plane means real-time control between DU and RU. The user plane may contain IQ sample data transmitted between DU and RU. The user plane may include the user's downlink data (IQ data or SSB/RS), uplink data (IQ data or SRS/RS), or PRACH data. The weight vector of the above-described beamforming information may be multiplied by the user's data. Synchronization plane generally refers to the traffic between DU and RU to a synchronization controller (e.g. IEEE Grand Master). The synchronization plane may be related to timing and synchronization. The management plane refers to non-real-time control between DU and RU. The management plane may be related to initial setup, non-realtime reset or reset, and non-realtime report.

Messages in the control plane, i.e. C-plane messages, can be encapsulated based on a two-layer header approach. The first layer may consist of the eCPRI common header or IEEE 1914.3 common header, which contains fields used to indicate the message type. The second layer is the application layer, which contains fields required for control and synchronization. Within the application layer, a section defines the characteristics of U-plane data transmitted or received on a beam with one pattern ID. The section types supported within C-plane are as follows.

Section Type may indicate the purpose of the control message transmitted in the control plane. For example, the purpose of each Section Type is as follows.

1) sectionType=0: Used to indicate unused resource blocks or symbols in DL or UL.

2) sectionType=1: Used for most DL/UL wireless channels. Here, “most” refers to channels that do not require time or frequency offset, such as is required for mixed numerology channels.

3) sectionType=2: reserved for further use

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

5) sectionType=4: reserved for further use

6) sectionType=5: UE scheduling information. Delivers UE scheduling information so that RU can calculate BF weight in real time (O-RAN optional BF method)

7) sectionType=6: UE-specific channel information transmission. Periodically transmit UE channel information so that RU can calculate BF weight in real time (O-RAN optional BF method)

8) sectionType=7: Used for LAA support

C-plane messages may be exchanged between DUs (eg, DU 210, O-DU 251) and RUs (eg, RU 220, O-RU 253-1). The main purpose of C-plane messages is to transmit data-related control information (e.g., scheduling and beamforming commands) required for user data processing when the data-related control information is not provided through the M-plane. Messages may be transmitted separately for DL-related commands and UL-related commands. Hereinafter, C-plane messages for downlink are shown in FIG. 5A, and C-plane messages for uplink are shown in FIG. 5B.

Figure 5A shows examples of downlink (DL) messages according to embodiments. DU illustrates DU 210 in FIG. 2A. According to one embodiment, DU 210 may include O-DU 251. RU illustrates RU 220 in FIG. 2A. According to one embodiment, RU 220 may include O-RU 253-1.

Referring to FIG. 5A, in operation 501, the DU 210 may transmit C-plane messages to the RU 220. RU 220 may receive C-plane messages from DU 210. C-plane messages can be transmitted through the fronthaul interface. C-plane messages can be composed in symbol units. For example, each C-plane message may include scheduling information for downlink signals in one or more symbols. For example, C-plane messages are for downlink signals from symbol #M to symbol #N (i.e., symbol #M, symbol #M+1, ..., symbol #N-1, symbol #N). May include scheduling. Scheduling information may be referred to as sections. The DL C-Plane message describing multiple symbols is sent to the RU 220 a certain period of time before the end of the DL U-Plane reception window for the indicated start symbol (e.g. startSymbolId). is required to arrive at

A C-plane message may be associated with one or more layers. The layer may be associated with eAxC between DU 210 and RU 220. According to one embodiment, a C-plane message may be associated with one layer. The C-plane message may include scheduling information for the downlink data stream corresponding to the one layer. According to another embodiment, a C-plane message may be associated with multiple layers. The C-plane message may include scheduling information about downlink data streams corresponding to different layers.

In operation 503, the DU 210 may transmit U-plane messages for symbol #M to the RU 220. The DU 210 may transmit a U-plane message for each layer to the RU 220 at symbol #M. RU 220 may receive U-plane messages for symbol #M from DU 210. The U-plane messages may be transmitted through the fronthaul interface. The U-plane message, in the symbol #M, may include an IQ sample of downlink data to be transmitted from the upper node to the UE through the radio access network. The RU 220 may transmit a U-plane message related to the layer corresponding to the antenna to the UE through an antenna.

In operation 505, DU 210 may transmit U-plane messages for symbol #M+1 to RU 220. The DU 210 may transmit a U-plane message for each layer to the RU 220 at symbol #M+1. RU 220 may receive U-plane messages for symbol #M+1 from DU 210. The U-plane messages may be transmitted through the fronthaul interface. The U-plane message may include an IQ sample of downlink data to be transmitted from the upper node to the UE through the radio access network at the symbol #M+1. The RU 220 may transmit a U-plane message related to the layer corresponding to the antenna to the UE through an antenna. Although not shown in FIG. 5A, according to one embodiment, the DU 210 may transmit U-plane messages for symbols #M+2, ..., and #N-1 to the RU 220, respectively. That is, through operations 503 to 507, the DU 210 may transmit U-plane messages including downlink signals scheduled based on C-plane messages to the RU 220.

In operation 507, DU 210 may transmit U-plane messages for symbol #N to RU 220. The DU 210 may transmit a U-plane message for each layer to the RU 220 at symbol #N. RU 220 may receive U-plane messages for symbol #N from DU 210. The U-plane messages may be transmitted through the fronthaul interface. The U-plane message, at symbol #N, may include an IQ sample of downlink data to be transmitted from the upper node to the UE through the radio access network. The RU 220 may transmit a U-plane message related to the layer corresponding to the antenna to the UE through an antenna.

FIG. 5B shows examples of uplink (UL) messages according to embodiments. DU illustrates DU 210 in FIG. 2A. According to one embodiment, DU 210 may include O-DU 251. RU illustrates RU 220 in FIG. 2A. According to one embodiment, RU 220 may include O-RU 253-1.

Referring to FIG. 5B, in operation 551, the DU 210 may transmit C-plane messages to the RU 220. RU 220 may receive C-plane messages from DU 210. C-plane messages can be transmitted through the fronthaul interface. C-plane messages can be composed in symbol units. For example, each of the C-plane messages may include scheduling information for uplink signals in one or more symbols. For example, C-plane messages are for uplink signals from symbol #M to symbol #N (i.e., symbol #M, symbol #M+1, ..., symbol #N-1, symbol #N). May include scheduling. Scheduling information may be referred to as sections. The UL C-Plane message describing multiple symbols is a symbol (e.g., start symbol (e.g., startSymbolId)) than a sample of the uplink signal that arrives first at the antenna of the RU 220. It is required to arrive at RU 220 before a certain period of time.

A C-plane message may be associated with one or more layers. The layer may be associated with eAxC between DU 210 and RU 220. According to one embodiment, a C-plane message may be associated with one layer. The C-plane message may include scheduling information for the uplink data stream corresponding to the one layer. According to another embodiment, a C-plane message may be associated with multiple layers. The C-plane message may include scheduling information about uplink data streams corresponding to different layers.

In operation 553, the RU 220 may transmit U-plane messages for symbol #M to the DU 210. RU 220 may receive UL signals at symbol #M. The RU 220 may receive a UL signal related to a layer corresponding to the antenna through an antenna. The RU 220 may generate IQ sample data for UL signals received at symbol #M. The RU 220 may transmit a U-plane message for each layer to the DU 210 at symbol #M. DU 210 may receive U-plane messages for symbol #M from RU 220. The U-plane messages may be transmitted through the fronthaul interface. The U-plane message may include IQ sample data of the uplink signal in the symbol #M.

In operation 555, RU 220 may transmit U-plane messages for symbol #M+1 to DU 210. RU 220 may receive UL signals at symbol #M+1. The RU 220 may receive a UL signal related to a layer corresponding to the antenna through an antenna. RU 220 may generate IQ sample data for UL signals received at symbol #M+1. The RU 220 may transmit a U-plane message for each layer to the DU 210 at symbol #M+1. DU 210 may receive U-plane messages for symbol #M from RU 220. The U-plane messages may be transmitted through the fronthaul interface. The U-plane message may include IQ sample data of the uplink signal in the symbol #M. Although not shown in FIG. 5B, according to one embodiment, the RU 220 may transmit U-plane messages for symbols #M+2, ..., and #N-1 to the DU 210, respectively. That is, through operations 553 to 557, the RU 220 sends U-plane messages containing UL signals, received in a section scheduled based on C-plane messages, to the DU 210. Can be transmitted.

In operation 557, RU 220 may transmit U-plane messages for symbol #N to DU 210. RU 220 may receive UL signals at symbol #N. The RU 220 may receive a UL signal related to a layer corresponding to the antenna through an antenna. RU 220 may generate IQ sample data for UL signals received at symbol #N. The RU 220 may transmit a U-plane message for each layer to the DU 210 at symbol #N. DU 210 may receive U-plane messages for symbol #N from RU 220. The U-plane messages may be transmitted through the fronthaul interface. The U-plane message may include IQ sample data of the uplink signal at symbol #N.

Figure 6 shows an example of resource allocation for each layer according to one embodiment. Resources may be allocated across multiple layers and multiple resource blocks (RBs) within a symbol. DUs (e.g., DU 210, O-DU 251) may perform resource allocation. The scheduler of the DU 210 can allocate resources for downlink transmission of the RU (e.g., RU 220, O-RU 253-1) or uplink transmission of the UE (e.g., terminal 120). there is. DU 210 may indicate an allocated resource area through C-plane messages. IQ samples corresponding to the downlink transmission or the uplink transmission may be provided from the DU 210 to the RU 220 through U-plane messages. The U-plane message may include IQ sample data (hereinafter referred to as U-plane data) for each layer in the RU 220.

Referring to FIG. 6, the horizontal axis of the chart 600 represents the frequency domain. The vertical axis of the resource chart 600 represents layers. Resource allocation can be performed on an RB basis. U-plane messages are transmitted in resource blocks (“PRBs”), and data for each PRB may start at a byte boundary. If the end of the data in the PRB does not fall within a byte boundary due to the IQ bit width, zero bits may be added until the byte boundary is reached. Hereinafter, resource allocation in RB units is assumed in each layer.

Within a certain area of the frequency domain, resource allocation may be performed for each layer. A certain area of the frequency domain may be indicated by section information of the C-plane message. For example, U-plane data of layer #0 may be assigned to RB #0 (601) and RB #1 (603). U-plane data of layer #1 can be assigned to RB #0 (601) and RB #1 (603). U-plane data of layer #2 can be assigned to RB #0 (601), RB #1 (603), and RB #2 (605). U-plane data of layer #3 can be assigned to RB #0 (601), RB #1 (603), and RB #2 (605). U-plane data of layer #4 can be assigned to RB #0 (601). U-plane data of layer #5 can be assigned to RB #0 (601), RB #1 (603), RB #2 (605), and RB #3 (607).

Meanwhile, during a certain section of the frequency domain, an unscheduled area (hereinafter referred to as a non-scheduled area) exists. For example, RB #2 (605) and RB #3 (607) of layer #0 correspond to the non-scheduling area. RB #2 (605) and RB #3 (607) of layer #1 correspond to the non-scheduling area. RB #3 (607) of layer #2 corresponds to the non-scheduling area. RB #3 (607) of layer #3 corresponds to a non-scheduling area. RB #1 (603), RB #2 (605), and RB #3 (607) of layer #4 correspond to the non-scheduling area.

DU (e.g., DU 210, O-DU 251) can provide channel information for each UE. RUs (e.g., RU 220, O-RU 253-1) perform beamforming for co-scheduled UEs in specific resources (e.g., slots) based on channel information. Weights can be calculated. An identifier associated with each data section (e.g., ueId (user identifier) of a C-plane message) may be used for beamforming. If a channel-information-based beamforming method is used for at least one layer (or spatial stream), the DU 210 can configure all layers (or The same beamforming method should be used for spatial streams). For example, for scheduling information of the channel information-based beamforming method, section type 5 of the C-plane message can be used. One or more identifiers (e.g. ueIds) may be associated with a section of a C-plane message. The DU 210 may provide scheduling information for each layer to the RU 220 through a corresponding ueId.

FIGS. 7A and 7B illustrate an example of beamforming using an indication of a non-scheduling layer according to an embodiment. The beamforming may include channel information-based beamforming. The DU 210 may provide scheduling information for each layer to a RU (e.g., RU 220, O-RU 253-1) through a corresponding ueId. In FIGS. 7A and 7B, to explain scheduling information using ueId, the resource allocation shown in FIG. 6 is assumed.

Referring to FIG. 7A, the horizontal axis of the chart 700 represents the frequency domain. The vertical axis of the resource chart 700 represents layers. ueId can be allocated on a section basis. For example, section 710 may include RB #0 (601), RB #1 (603), RB #2 (605), and RB #3 (607).

According to one embodiment, a group configuration for multiple ports may be used to indicate a section. For example, Section Extension 10 (SE 10) of the O-RAN standard can be used for C-plane messages. C-plane section information for multiple ports (ie, layers or Tx/Rx paths) may be the same except for beam ID or UE IDs. If multiple ports share common section information within the RU 220, C-plane sections to be transmitted through the corresponding ports can be merged into one C-plane section through a representative port using SE 10. there is. For example, to merge C-plane sections, section extension information as shown in the table below may be added to the C-plane message.

'ef' can indicate the presence or absence of a section extension. For example, if 'ef' is 1, it may indicate the existence of a section extension field, and if 'ef' is 0, it may indicate the absence of a section extension field. 'extType' indicates the type of the extension field, and extLen' indicates the length in the extension field in bytes. 'numPortc' may indicate the number of ports (e.g., eAxC ports) (or the number of layers, the number of transmission/reception paths) indicated by the extension field. For example, through 6-bit, 'numPortc' can indicate up to 64 ports. 'beamGroupType' may indicate the type of beam grouping. If 'beamGroupType' is '00b', the beam ID of the section header can be used as a common beam ID for all ports. When 'beamGroupType' is '01b', 'numPortc' consecutive beam IDs or ueIds following the beam ID or ueId of the section header can be applied to ports according to 'numPortc'. When 'beamGroupType' is '10b', 'numPortc' consecutive or discontinuous beam IDs or ueIds following the beam ID or ueId of the section header can be applied to ports according to 'numPortc'. If 'beamGroupType' is '10b', the table below can be referred to.

The extension field may include as many beamIDs (or ueIds) as 'numPortc'. Single user and multi-user can be distinguished depending on whether there is overlap during scheduling within a designated frequency region (e.g., one or more RBs). For example, a C-plane message to which Table 2 is added can provide resource allocation for multiple UEs within the same section. That is, the C-plan message can correspond to a multi-user schedule. Resource allocation in FIG. 6 is performed for six layers within the same section and corresponds to MU-MIMO.

In chart 700, 'numPortc' may be 5. Scheduling information for a total of 6 ports can be provided through C-plane messages. For example, a C-plane message may include a message format according to Section Type 5 and Section Extension 10 of the O-RAN standard. Each port may represent a layer of MU-MIMO. The DU 210 can receive a ueId from each layer among the layers for MU-MIMO. For example, the ueId for layer #0 in section 710 may be set to 1. In section 710, the ueId for layer #1 may be set to 2. In section 710 the ueId for layer #2 may be set to 10. In section 710 the ueId for layer #3 may be set to 11. In section 710 the ueId for layer #4 may be set to 24. In section 710, the ueId for layer #5 may be set to 30. At this time, ueId may also be assigned to an area without actual U-plane data (e.g., RB #2 (605) of layer #0).

RU 220 may receive a C-plane message. RU 220 may identify section 710 . RU 220 may identify ueIds corresponding to section 710 . RU 220 may calculate beamforming weights for ueIds. For example, when K layers are commonly scheduled for MU-MIMO, the beamforming matrix W can be applied to frequency domain IQ data for the K layers. However, although the scheduled area for each layer is different, beamforming is performed assuming that the same frequency area is allocated to each layer, which may cause deterioration of beamforming performance.

In some frequency regions, at least one layer may not be scheduled. For example, in RB #0 (601), scheduling is performed for all layers, but in RB #2 (605), layer #2 of UE #2, layer #3 of UE #2, and layer # of UE #4 Scheduling for 5 is performed. At this time, the DU 210 may provide scheduling information to the RU 220. However, the DU 210 provides the RU 220 with information about unscheduled layers (e.g., layer #0, layer #1, layer #4) in a specific frequency region (e.g., RB #2 (605)). If not, the RU 220 cannot know whether the specific area is not scheduled, or is scheduled, but the RU 220 has not yet received the information. If RB #2 (605) assumes MU-MIMO beamforming for six layers as in RB #1, the beamforming weight is calculated based on both the unscheduled layer and the scheduled layer.

Beamforming weights for six layers can be calculated across RB #0 (601), RB #1 (603), RB #2 (605), and RB #3 (607). Even though the RBs of some layers are not scheduled, they are included as elements for calculating beamforming weights, so the beamforming weights may be derived unsuitably for actual scheduling results. In addition, since beamforming is calculated for a larger number of layers than the actual scheduled layers, the beamforming gain may decrease. In order to solve the above-described problem, the electronic device and method according to embodiments of the present disclosure improve the accuracy of the beamforming weight by indicating an unscheduled layer (hereinafter, a non-scheduling layer) in MU-MIMO beamforming. We propose a method to increase beamforming gain.

The DU 210 according to embodiments may transmit information for indicating a non-scheduling layer in beamforming for MU-MIMO to the RU 220. According to one embodiment, a specific value of ueId of the C-plane message of Section Type 5 of the O-RAN standard may be used to indicate a non-scheduling layer. In the scheduling information of the C-plane message of Section Type 5, ueId may indicate the layer. Instead of indicating the layer scheduled for MU-MIMO within the section, ueId may indicate a non-scheduled layer. For example, ueId may be 16-bit. If the value of ueId is 0x7FFF (=2 ¹⁵ -1) ('111 1111 1111 1111b'), the non-scheduling layer can be indicated. The DU 210 may identify an unscheduled layer, that is, a non-scheduled layer, and set the ueId for the non-scheduled layer to 0x7FFF. The RU 220 can identify the layer corresponding to the ueId set to 0x7FFF. The RU 220 may perform beamforming based on identifying that there is no U-plane data of the identified layer. Even if the RU 220 receives a U-plane message in the corresponding layer from the DU 210, the RU 220 may ignore the U-plane data.

Referring to FIG. 7B, the horizontal axis of the chart 750 represents the frequency domain. The vertical axis of the resource chart 700 represents layers. ueId can be allocated on a layer and RB basis. ueId=0x7FFF may be assigned for RB #2 (605) and RB #3 (607) of layer #0. ueId=0x7FFF may be assigned for RB #2 (605) and RB #3 (607) of layer #1. ueId=0x7FFF may be assigned for RB #3 (607) of layer #2. ueId=0x7FFF may be assigned for RB #3 (607) of layer #3. ueId=0x7FFF may be assigned for RB #1 (603), RB #2 (605), and RB #3 (607) of layer #4.

According to one embodiment, the DU 210 may indicate the non-scheduling layer to the RU 220 through section extension information in the C-plane message. For example, the DU 210 may transmit a C-plane message for layers #0 to layer #5 to the RU 220. The C-plane message may include scheduling information for RB #2 (605). The section extension information of the C-plane message includes 'numPortc=5' and may include 5 ueIds. The ueId and additional five ueIds included in the section area of the C-plane message may refer to layer #0, layer #1, layer #2, layer #3, layer #4, and layer #5, respectively. Each of the non-scheduling layers may have a predefined value. The value of ueId for layer #0 may be '0x7FFF'. The value of ueId for layer #1 may be '0x7FFF'. The value of ueId for layer #4 may be '0x7FFF'. Each of the actually scheduled layers may have a unique ueId value. The value of ueId for layer #2 may be '0x000A'. The value of ueId for layer #3 may be '0x000B'. The value of ueId for layer #5 may be '0x001E'.

According to another embodiment, the DU 210 may indicate a non-scheduling layer to the RU 220 through transmission of a C-plane message for each layer. For example, the DU 210 may transmit a C-plane message for layer #0 to the RU 220. Information in the header of the C-plane message (e.g., eAxC ID) may point to layer #0. The sections of the C-plane message point to RB #2 (605) and RB #3 (607), and the ueId of the C-plane message may be set to 0x7FFF. In this way, non-scheduling areas for each of layer #1, layer #2, layer #3, and layer #4 can be indicated.

The RU 220 may calculate beamforming weights based on jointly scheduled layers for MU-MIMO. Beamforming weights include a beamforming matrix and can be applied to IQ data in the frequency domain. RU 220 may identify a non-scheduling layer. The RU 220 may calculate the beamforming weight based on at least one layer different from the non-scheduling layer. For example, the RU 220 may calculate the beamforming weight 761 in RB #0 601 based on six ueIds. In RB #0 (601), MU-MIMO beamforming for six layers can be performed.

The RU 220 may calculate the beamforming weight 763 in RB #1 603 based on the five ueIds. In RB #1 603, layer #4 may be indicated as a non-scheduling layer. Here, the beamforming weight for layer #4 is not set to '0'. This means that before calculating the beamforming weight, the ueId for layer #4 is excluded from the array elements for calculating the beamforming weight. Therefore, the weight for layer #4 is not calculated. And, the RU 220 can calculate beamforming weights 763 for five layers. In RB #1 (603), MU-MIMO beamforming for five layers can be performed.

The RU 220 may calculate the beamforming weight 765 in RB #2 605 based on the three ueIds. In RB #2 605, layer #0, layer #1, and layer #4 may be indicated as non-scheduling layers. Here, the beamforming weight for layer #4 is not set to '0'. This means that before calculating the beamforming weight, the ueId for layer #4 is excluded from the array elements for calculating the beamforming weight. Therefore, beamforming weights for each of layer #0, layer #1, and layer #4 are not calculated. And the RU 220 can calculate beamforming weights 765 for three layers. In RB #1 (603), MU-MIMO beamforming for three layers can be performed.

The RU 220 may calculate the beamforming weight 767 in RB #3 607 based on the ueId of layer #5. The RU 220 may calculate the beamforming weight assuming a single user rather than MU-MIMO beamforming.

In FIG. 7B, 0x7FFF (=2 ¹⁵ -1) is illustrated as a predefined value of ueId to indicate a non-scheduled layer, but embodiments of the present disclosure are not limited thereto. For example, a value indicating a non-scheduled layer may be defined as a different value (e.g., 0x0FF (=255)). Additionally, in FIG. 7B, the value indicating the non-scheduled layer is described as being standardized in advance, but embodiments of the present disclosure are not limited thereto. For example, a value indicating a non-scheduled layer may be defined based on the M-plane parameter.

Figure 8 shows an example of beamforming weight for each resource area according to an embodiment. To explain the applied beamforming weight, in FIG. 8 the resource allocation shown in FIG. 6 and the ueIds in FIG. 7B are assumed.

Referring to FIG. 8, a chart 800 shows beamforming weights for each RB. Beamforming weights may include a beamforming matrix. The beamforming matrix may be calculated based on channel information according to specified criteria (e.g., minimum mean square error (MMSE), zero forcing (ZF)). The beamforming matrix may include factors for each layer. For example, in RB #0 (601), the RU (220) may obtain the beamforming weight (761) (W _RB0 ). The beamforming weight 761 (W _RB0 ) is calculated by receiving as input a matrix [h ₁ h ₂ h ₁₀ h ₁₁ h ₂₄ h ₃₀ ] consisting of 6 channel information. Each channel information corresponds to the scheduled ueId.

In an unscheduled layer, that is, an RB where a non-scheduling layer exists, the beamforming weight may be calculated in a different way. The beamforming weight calculation method according to the direction of the non-scheduling layer according to embodiments of the present disclosure does not consider the non-scheduling layer as an array element for the beamforming matrix. For example, in RB #1 (603), the RU (220) may obtain the beamforming weight (763). The beamforming weight 763 (W _RB1 ) is calculated by receiving as input a matrix [h ₁ h ₂ h ₁₀ h ₁₁ h ₃₀ ] consisting of 5 channel information. Since layer #4 is not scheduled, it is not provided as an input to the calculation of h ₂₄ beamforming weight 763, which is channel information for layer #4. Additionally, for example, the RU 220 may obtain a beamforming weight 765 in RB #2 605. The beamforming weight 763 (W _RB1 ) is calculated by receiving as input a matrix [h ₁ h ₂ h ₁₀ h ₁₁ h ₃₀ ] consisting of three channel information. Each channel information corresponds to a scheduled ueId. Since layer #0, layer #1, and layer #4 are not scheduled, h ₁ , h ₂ , and h ₂₄ , the channel information for layer #0, layer #1, and layer #4, are beamforming weights 763 It is not provided as input to the calculation of .

If the number of layers scheduled by the non-scheduling layer is one, the C-plane message formally indicates MU-MIMO beamforming, but the actually calculated beamforming weight may indicate SU-MIMO beamforming. For example, in RB #3 (607), the RU (220) may obtain the beamforming weight (767). The beamforming weight 763 (W _RB3 ) can be calculated with h ₃₀ , which is the channel of the scheduled ueId. Layer #0, Layer #1, Layer #2, Layer #3, and Layer #4 are not scheduled, so layers configured for MU-MIMO beamforming (e.g. Layer #0, Layer #1, Layer #2) , among layers #3, layer #4, and layer #5), h _300,000 , which is the channel information scheduled for layer #5, is also provided as input to the calculation of the beamforming weight 763.

Since different scheduling results are used for each RB, the beamforming weight may be calculated differently for each RB. Additionally, as mentioned for each RB in FIG. 8, channel information corresponding to the non-scheduling layer is not used as an input for beamforming weight calculation. The non-scheduling layer is a nulling layer in which only the beamforming weight is calculated for the layer to which no U-plane data is assigned by intentionally scheduling only the C-plane ueId without allocating U-plane data due to interference after scheduling. different. Additionally, since beamforming weights are not assigned to unnecessary layers, beamforming gain can be increased.

FIG. 9 illustrates the functional configuration of a DU and a RU for beamforming using instructions from a non-scheduling layer according to an embodiment. DU illustrates DU 210 in FIG. 2A. According to one embodiment, DU 210 may include O-DU 251. RU illustrates RU 220 in FIG. 2A. According to one embodiment, RU 220 may include O-RU 253-1.

Referring to FIG. 9, the DU 210 may include a scheduler 901, a modem 903, a C-plane processing unit 910a, and a U-plane processing unit 920a. The scheduler 901 may perform resource allocation. Resource allocation refers to scheduling of U-plane data, that is, signals to be transmitted on a wireless access network. Resource allocation can be performed on a layer and RB basis. The ueId of the C-plane message of Section Type 5 of the O-RAN standard may indicate the ueId assigned to the layer. According to one embodiment, the scheduler 901 may perform resource allocation based on ueId. The result of resource allocation can be distinguished by ueId. According to one embodiment, a specific value of ueId in a specific RB area may be used to indicate an unscheduled layer. For example, ueId pointing to 0x7FFF may point to an unscheduled layer.

The modem 903 may perform modulation and demodulation on signals to be transmitted on a wireless access network. The modem 903 may receive scheduled signals from the scheduler 901. The modem 903 may generate IQ sample data corresponding to scheduled signals. The signals may be provided to the RU 220 on the fronthaul interface in the form of U-plane messages. The modem 903 may provide IQ sample data to the U-plane processing unit 920a.

The C-plane processing unit 910a can generate a C-plane message. The C-plane processing unit 910a may generate a C-plane message based on the scheduling result received from the scheduler 901. According to one embodiment, the C-plane processing unit 910a may generate a C-plane message including a ueId to indicate an unscheduled layer. The C-plane processing unit 910a may transmit a C-plane message to the RU 220. The C-plane processing unit 910a may transmit a C-plane message to the C-plane processing unit 910b of the RU 220. C-plane messages may be provided on the fronthaul interface between DU 210 and RU 220.

The U-plane processing unit 920a may generate a U-plane message. The U-plane processing unit 920a may obtain IQ sample data from the modem 903. The U-plane processing unit 920a may generate a U-plane message including IQ sample data. The U-plane processing unit 920a may transmit a U-plane message to the RU 220. The U-plane processing unit 920a may transmit a U-plane message to the U-plane processing unit 920b of the RU 220. U-plane messages may be provided on the fronthaul interface between DU 210 and RU 220.

The RU 220 may include a C-plane processing unit 910b, a U-plane processing unit 920b, a beamforming weight generator 930, and a beamforming unit 940.

The C-plane processing unit 910b may receive a C-plane message from the DU 210. The C-plane processing unit 910b may receive a C-plane message from the C-plane processing unit 910a of the DU 210. The C-plane processing unit 910b can process the received C-plane message. According to one embodiment, the C-plane processing unit 910b may identify scheduling information of the C-plane message. The C-plane processing unit 910b can identify whether scheduling is performed for each layer in a designated frequency region (e.g., RB). The C-plane processing unit 910b may provide scheduling results to the beamforming weight generator 930. The C-plane processing unit 910b may provide ueId and information about ueId to the beamforming weight generator 930.

The U-plane processing unit 920b may receive a U-plane message from the DU 210. The U-plane processing unit 920b may receive a U-plane message from the U-plane processing unit 920a of the DU 210. The U-plane processing unit 910b can process the received U-plane message. The U-plane processing unit 920b may provide IQ sample data of the U-plane message to the beamforming weight generator 930.

The beamforming weight generator 930 may calculate the beamforming weight. Beamforming weights may be calculated at RU 220 based on channel estimates. According to one embodiment, the beamforming weight generator 930 may be configured not to generate beamforming weights for non-scheduling layers. The beamforming weight generator 930 may identify the scheduling layer. The beamforming weight generator 930 may identify a non-scheduling layer. According to one embodiment, the beamforming weight generator 930 may identify a non-scheduling layer based on the value of ueId. If ueId points to a value designated for non-scheduling (e.g., 0x7FFF or 0x00FF (=2 ⁸ -1) ('000 0000 1111 1111')), the beamforming weight generator 930 generates a section of the C-plane. Within this, it can be identified that the corresponding layer is not scheduled. Even if a plurality of layers for MU-MIMO are configured through the C-plane, the beamforming weight generator 930 does not calculate the beamforming weight for the plurality of layers, but only for at least one scheduled layer. Beamforming weights can be calculated. In other words, non-scheduling layers are not included as array elements in the beamforming weight matrix.

The beamforming unit 940 may perform beamforming. The beamforming unit 940 may apply beamforming weights. Beamforming weights may be applied to frequency domain IQ data for one or more layers. Beamforming weights can be applied to the IQ sample data of the U-plane message. The RU 220 may transmit downlink signals to which beamforming weights are applied through the beamforming unit 940. For example, the RU 220 may transmit downlink signals to the UE (e.g., the terminal 120).

In FIG. 9, DL U-plane data processing is described as an example, but embodiments of the present disclosure are not limited thereto. Embodiments of the present disclosure can also be applied to UL U-plane data processing. According to one embodiment, the U-plane processing unit 920a of the DU 210 may receive a U-plane message from the U-plane processing unit 920b of the RU 220. The U-plane message may include IQ sample data for the uplink signal.

Figure 10 shows the operation flow of a DU for indicating a non-scheduling layer according to an embodiment. DU illustrates DU 210 in FIG. 2A. According to one embodiment, DU 210 may include O-DU 251.

Referring to FIG. 10, in operation 1001, the DU 210 may identify non-scheduling for a layer in the resource region. The resource area is a time-frequency resource and may mean an RB area corresponding to a symbol. A resource area may be referred to as a data section. The DU 210 may identify an unscheduled layer, that is, a non-scheduled layer, in the RB area.

In operation 1003, the DU 210 may generate a C-plane message that includes UE identification information corresponding to information about the resource region and a value to indicate non-scheduling for the layer. Information about the resource area may include section information indicating the RB area corresponding to the symbol. Through the position of the starting PRB (eg, startPrbc) and the number of consecutive PRBs (eg, numPrbc), the C-plane message can indicate the resource area. UE identification information can be used for channel information-based beamforming. For scheduling of MU-MIMO beamforming, individual layers may correspond to UE identification information. UE identification information may include a ueId parameter to provide the label of the UE to which the section content applies. For example, the ueId parameter may be composed of 15-bit. According to one embodiment, the UE identification information points to a predefined value to indicate non-scheduling of a layer, or a preconfigured value to indicate non-scheduling of a layer (e.g., M-plane parameter ) can refer to. For example, if the value of the ueId parameter is 0x7FFF, non-scheduling of the layer corresponding to the ueId parameter may be indicated. For another example, if the last 8 bits of the bits of the ueId parameter indicate 255, non-scheduling of the layer corresponding to the ueId parameter may be indicated.

According to one embodiment, C-plane messages may be transmitted for each layer. The C-plane message may include scheduling information of the corresponding layer. For example, a C-plane message may have a message format of Section Type 5 of the O-RAN standard. To calculate beamforming weights for a layer, channel information related to UE identification information may be used. C-plane messages that contain scheduling information and other C-plane messages may be related to unscheduled layers. In the C-plane message, the ueId parameter included in the section information of the C-plane message of Section Type 5 may indicate non-scheduling. The C-plane message may indicate that the resource area is a non-scheduling area.

According to another embodiment, the C-plane message may include scheduling information for a plurality of layers. For example, a C-plane message may have a message format of Section Type 5 of the O-RAN standard. Additionally, the C-plane message may include section extension information (e.g., SE 10 of the O-RAN standard) for group configuration of multiple ports. The C-plane message may include UE identification information for each of a plurality of layers in the same resource area. At this time, the ueId parameter of UE identification information related to the non-scheduled layer may indicate non-scheduling. For example, when the unscheduled layer, that is, the non-scheduled layer, is the first layer, the ueId of the section information of the C-plane message may indicate non-scheduling. Additionally, for example, if the non-scheduled layer, that is, the non-scheduled layer, is not the first layer, within the section extension information of the C-plane message, the ueId corresponding to the order of the non-scheduled layer is non-scheduled. -Scheduling can be instructed.

At operation 1005, DU 210 may transmit a C-plane message. The DU 210 may transmit a C-plane message to the RU 220 through the fronthaul interface. The C-plane message can be used to calculate beamforming weights for beamforming in the RU 220.

Although not shown in FIG. 10, a U-plane message for signal transmission in the area scheduled by the C-plane message may be transmitted on the fronthaul interface. For example, in the case of downlink transmission, the DU 210 may transmit a U-plane message corresponding to a layer other than the non-scheduling layer to the RU 220 within the resource area of the C-plane. Additionally, for example, in the case of uplink transmission, the DU 210 Within the resource area of the C-plane, a U-plane message corresponding to a layer other than the non-scheduling layer may be received from the RU 220.

The indication of the non-scheduling layer may be used by the RU 220 to calculate a beamforming weight to be applied to the signal transmitted on the radio access network. As the indicated non-scheduling layer is excluded from the calculation of the beamforming weight, a beamforming weight suitable for actual scheduling can be obtained. Additionally, since allocation to unnecessary layers is not considered, beamforming gain can be increased.

Figure 11 shows the operation flow of an RU for indicating a non-scheduling layer according to an embodiment. RU illustrates RU 220 in FIG. 2A. According to one embodiment, RU 220 may include O-RU 253.

Referring to FIG. 11, in operation 1101, the RU 220 receives a C-plane message containing UE identification information corresponding to information on the resource area and a value for indicating non-scheduling for the layer. You can. Information about the resource area may include section information indicating the RB area corresponding to the symbol. Through the position of the starting PRB (eg, startPrbc) and the number of consecutive PRBs (eg, numPrbc), the C-plane message can indicate the resource area. UE identification information can be used for channel information-based beamforming. For scheduling of MU-MIMO beamforming, individual layers may correspond to UE identification information. UE identification information may include a ueId parameter to provide the label of the UE to which the section content applies. For example, the ueId parameter may be composed of 15-bit. According to one embodiment, the UE identification information points to a predefined value to indicate non-scheduling of a layer, or a preconfigured value to indicate non-scheduling of a layer (e.g., M-plane parameter ) can refer to. For example, if the value of the ueId parameter is 0x7FFF, non-scheduling of the layer corresponding to the ueId parameter may be indicated. For another example, if the last 8 bits of the bits of the ueId parameter indicate 255, non-scheduling of the layer corresponding to the ueId parameter may be indicated.

In operation 1103, the RU 220 may calculate beamforming weights based on the C-plane message. RU 220 may identify a non-scheduling layer based on the C-plane message. The RU 220 may identify at least one layer scheduled based on the C-plane message or another C-plane message. The RU 220 may calculate a beamforming weight for at least one scheduled layer by excluding the non-scheduled layer. That is, the indicated non-scheduling layer is not used as an input for calculating the beamforming weight.

According to one embodiment, C-plane messages may be transmitted for each layer. To calculate the beamforming weight for a layer, channel information related to UE identification information corresponding to the layer may be used. For example, a C-plane message may have a message format of Section Type 5 of the O-RAN standard. A C-plane message for at least one layer may indicate scheduling of the corresponding layer in the section. C-plane messages for the non-scheduling layer may indicate non-scheduling in the section. The ueId parameter included in the section information of the C-plane message for the non-scheduling layer may indicate non-scheduling. The section of the C-plane message may be a non-scheduling area.

According to another embodiment, the C-plane message may include scheduling information for a plurality of layers. For example, a C-plane message may have a message format of Section Type 5 of the O-RAN standard. Additionally, the C-plane message may include section extension information (e.g., SE 10 of the O-RAN standard) for group configuration of multiple ports. The C-plane message may include UE identification information for each of a plurality of layers in the same resource area. At this time, the ueId parameter of UE identification information related to the non-scheduled layer may indicate non-scheduling.

The RU 220 may calculate the beamforming weight based on the scheduled layer(s), excluding the non-scheduled layer, within a specific resource area. Beamforming weight refers to the arrangement of at least one scheduled layer. The array may include weight values to be applied to IQ data in each layer. The size of the array corresponds to the number of at least one scheduled layer. Therefore, even if the C-plane message indicates six layers, if the UE identification information of one layer indicates that one layer as a non-scheduling layer, the beamforming weight (W) for each of the five layers Can include weight values.

The RU 220 may calculate beamforming weights based on channel information. For example, the RU 220 may calculate a beamforming weight based on periodically provided channel information (e.g., channel information of the C-plane message of Section Type 6). Additionally, for example, the RU 220 may calculate a beamforming weight based on the channel information and scheduling information (e.g., section information of the C-plane message of Section Type 5). The RU 220 may calculate the beamforming weight based on channel information of the scheduled layer. At this time, if the value of ueId indicates non-scheduling, the RU 220 may ignore the channel information of the layer corresponding to the ueId. If the value of ueId does not indicate non-scheduling, the RU 220 may calculate a beamforming weight based on channel information of the layer corresponding to the ueId.

At operation 1105, RU 220 may perform beamforming. The RU 220 may perform beamforming based on the calculated beamforming weight. The RU 220 may transmit downlink signals through beamforming. The downlink signals may be transmitted on scheduled radio resources through C-plane messages. IQ sample data for the downlink signals may be provided to the RU 220 through a U-plane message for each layer. RU 220 may receive U-plane messages from DU 210. The weight value corresponding to a specific layer may be applied to the IQ sample data of the U-plane message corresponding to the specific layer. Here, a specific layer may be associated with ueId. According to one embodiment, when the ueId indicates non-scheduling, the RU 220 may not receive the U-plane message corresponding to the layer of the ueId, or may ignore or discard the U-plane message even if it is received.

In FIG. 11, beamforming of the RU 220 is described assuming downlink transmission, but embodiments of the present disclosure are not limited thereto. The instructions of the non-scheduling layer can also be applied for beamforming of UL signals. Based on the indication of the non-scheduling layer, a beamforming matrix for UEs jointly scheduled for MU-MIMO can be calculated.

Figures 12A and 12B show examples of C-plane messages for indicating a non-scheduling layer according to one embodiment. C-plane messages may have a message format according to Section Type 5 of the O-RAN standard. In Figure 12a, when SE 10 of the O-RAN standard is not used, a C-plane message 1200 to indicate a non-scheduling layer is described. In Figure 12b, when SE 10 of the O-RAN standard is used, a C-plane message to indicate a non-scheduling layer is described.

Referring to FIG. 12A, the C-plane message 1200 may include a transport header (eg, eCPRI header or IEEE 1914.3) information. Transport headers may include 'ecpriVersion', 'ecpriReserved, 'ecpriConcatenation', 'ecpriMessage', 'ecpriPayload', 'ecpriRtcid/ecpriPcid', and 'ecpriSeqid', as described above.

The C-plane message 1200 may include common header information. Common header information is 'dataDirection' indicating the data transmission direction of the base station (e.g. gNB), 'payloadVersion' indicating the valid payload protocol version of IEs in the application layer, and the channel between IQ data and air interface to be used in both DL and UL. It can include 'filterindex', which means the index for the filter (channel filter).

Common header information may include information to indicate the location of a time resource to which the message is applicable. The location of a time resource may be indicated by a frame, subframe, slot, or symbol. Common header information may include 'frameId' indicating a frame number, 'subframeId' indicating a subframe number, 'slotId' indicating a slot number, and 'startSymbolId' indicating a symbol number. The frame is determined based on arithmetic modulo 256. A subframe has units of 1ms included in a 10ms frame. Slot numbers are numbered within the subframe, and the maximum size can be 1, 2, 4, 8, or 16 depending on the numerology.

Common header information may include 'numberOfsections' indicating the number of data sections included in the C-plane message 1200. Common header information may include 'sectionType' that determines the characteristics of U-plane data. Common header information may include 'timeoffset', which defines the offset from the start of the slot to the start of the CP (cyclic prefix) as the number of samples (e.g., T _s = 1/30.72 MHz (megahertz)). Common header information may include 'frameStructure' that defines fast fourier transfer (FFT)/inverse FFT (iFFT) size and SCS. Common header information may include 'cpLength', which defines the CP length as the number of samples (e.g., T _s = 1/30.72 MHz (megahertz)).

C-plane message 1200 may include section information. Section information may include 'sectionId', which means a section identifier. When C-Plane and U-Plane coupling via 'sectionId' is used, 'sectionId' identifies an individual data section described by the data section description in the C-Plane message 1200. The purpose of 'sectionId' is to map a U-Plane data section to the corresponding C-Plane message 1200 (and section type) associated with the data. Section information is 'rb' indicating whether all RBs are used (every RB is used) or every other RB (every other RB) is used, 'symInc' indicating a symbol number increment command, and data 'startPrbc' to indicate the start PRB number of the data section description, 'numPrbc' to indicate the number of consecutive PRBs for each data section description, 'reMask' to define the RE mask in the PRB, 'numSymbol', which defines the number of PRACH (physical random access channel) repetitions or the number of symbols, 'ef', which indicates the extension flag, and 'ueId', which defines the beam pattern to be applied to U-plane data. It can be included.

In the channel information-based beamforming method, the DU 210 uses Section Type 6 C-plane message(s) to periodically (generally less often than every slot) channel information for each UE. can be provided. Next, on a slot-by-slot basis, the DU 210 can provide scheduling information using a Section Type 5 C-plane message that must be used together with channel information. RU 220 may calculate appropriate beamforming weights for co-scheduled UEs and specific slots. The RU 220 may use the latest available channel information for ueId for channel information-based beamforming operation. That is, the RU 220 can use channel information about 'ueId' available to the RU 220 at the end of the reception window of the C-plane message of Section Type 5.

Assume layer #2 in the resource allocation shown in Figure 6. Layer #2 is scheduled in RB #0 (601), RB #1 (603), and RB #2 (605), and is not scheduled in RB #3 (607). Therefore, the C-plane message may include two sections for layer #2. The first section for layer #2 (e.g. sectionId = xx) may include RB #0 (601), RB #1 (603), and RB #2 (605). To indicate RB #0 (601), RB #1 (603), and RB #2 (605), startPRBc may point to 0 and numPrbc may point to 3. The second section for layer #2 (e.g. sectionId = xx+1) may include RB #3 (607). To point to RB #3 (607), startPRBc can point to 3 and numPrbc can point to 1. Here, since the first section is a scheduled area, the ueId value may be assigned as 11. For example, ueId[14:0] may point to '11'. However, since the second section is an unscheduled area, the ueId value can be set to a value to indicate a non-scheduling layer. According to one embodiment, the DU 210 may set the ueId value to a value defined for the non-scheduling layer. For example, ueId[14:0] may point to '0x7FFF'. As another example, ueId[14:0] may point to '255'. According to another embodiment, the DU 210 may set some areas (eg, least significant bit (LSB) 8-bit) of the bits of ueId to a specific value to indicate a non-scheduling layer. DU 210 may not use all 15 bits for ueId, but may use some bits. For example, ueId[7:0] may point to '255'.

Referring to FIG. 12b, the C-plane message 1250 may include a transport header (eg, eCPRI header or IEEE 1914.3) information. The C-plane message 1250 may include common header information. C-plane message 1250 may include section information. For individual fields of the transport header information, common header information, and section information of the C-plane message 1250, the description of the C-plane message 1200 of FIG. 12A may be referred to.

C-plane message 1250 may include section extension information. Section extension information may have a format according to SE 10. For example, section expansion information may have the format shown in Table 2. Assume RB #1 (603) in the resource allocation shown in FIG. 6. For common resource allocation for layers in RB #1 603, a C-plane message 1250 including section extension information according to SE 10 may be provided to the RU 220. The DU 210 may indicate scheduling information for the first layer (e.g., layer #0) among six layers in RB #1 603 through section information of the C-plane message 1250. Scheduling information for the remaining layers (e.g., layer #1, layer #2, layer #3, layer #4, layer #5) may be indicated through section extension information of the C-plane message 1250. The remaining layers may be respectively (respectively) assigned to 2 ^nd port ueId, 3 ^rd port ueId, 4 ^th port ueId, 5 ^th port ueId, and 6 ^th port ueId according to SE 10.

At RB #1 603, UE #3 is not scheduled. In other words, RB #1 (603) of layer #4 is a non-scheduling area. To indicate a non-scheduling area in RB #1 (603), ueId can be set to a specified value. According to one embodiment, the DU 210 may set the value of ueId to a value defined for the non-scheduling layer. For example, ueId[14:0] may point to '0x7FFF'. As another example, ueId[14:0] may point to '255'. According to another embodiment, the DU 210 may set some areas (eg, least significant bit (LSB) 8-bit) of the bits of ueId to a specific value to indicate a non-scheduling layer. DU 210 may not use all 15 bits for ueId, but may use some bits. For example, ueId[7:0] may point to '255'.

In embodiments, an electronic device of a radio unit (RU) includes at least one fronthaul transceiver, at least one radio frequency (RF) transceiver, and a combination of the at least one fronthaul transceiver and the at least one RF transceiver. It may include at least one processor. The at least one processor is a control plane (C-plane) including information about the resource area and UE (user equipment) identification information corresponding to a value indicating non-scheduling of the layer. ) may be configured to receive a message from a distributed unit (DU) through a fronthaul interface. The at least one processor may be configured to calculate a beamforming weight based on the C-plane message. The at least one processor may be configured to perform beamforming based on the beamforming weight.

According to one embodiment, the beamforming weight may be an arrangement for at least one layer scheduled in the resource region. The array may include weight values to be applied to IQ (in-phase and quadrature-phase) data in each layer. The size of the array may correspond to the number of the at least one layer. The at least one layer may not include the layer for which the non-scheduling is indicated.

According to one embodiment, the beamforming weight may be calculated based on channel information received from the DU.

According to one embodiment, the C-plane message may include section extension information for group configuration of multiple ports. The section extension information may include UE identification information for each of the additional layers. The additional layers include the layer for which the non-scheduling is indicated, and UE identification information for the layer may be included in the section extension information.

According to one embodiment, the UE identification information may include a ueId parameter for providing a label of the UE to which section content is applied. The ueId parameter is 15-bit, and the value indicating the non-scheduling may be 0x7FFF, 0x00FF, or a value set by M-plane.

In embodiments, 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 identify non-scheduling for a layer in the resource area. The at least one processor sends a control plane (C-plane) message including information about the resource area and UE (user equipment) identification information corresponding to a value indicating the non-scheduling of the layer. Can be configured to generate. The at least one processor may be configured to transmit the generated C-plane message to a radio unit (RU). The C-plane message may be related to beamforming weight in the RU.

According to one embodiment, the beamforming weight may be an arrangement for at least one layer scheduled in the resource region. The array may include weight values to be applied to IQ (in-phase and quadrature-phase) data in each layer. The size of the array may correspond to the number of the at least one layer. The at least one layer may not include the layer for which the non-scheduling is indicated.

According to one embodiment, the at least one processor may be configured to transmit channel information to the RU. The channel information may be used for the beamforming weight.

According to one embodiment, the C-plane message may include section extension information for group configuration of multiple ports. The section extension information may include UE identification information for each of the additional layers. The additional layers include the layer for which the non-scheduling is indicated, and UE identification information for the layer may be included in the section extension information.

According to one embodiment, the UE identification information may include a ueId parameter for providing a label of the UE to which section content is applied. The ueId parameter is 15-bit, and the value indicating the non-scheduling may be 0x7FFF, 0x00FF, or a value set by M-plane.

In embodiments, a method performed by a radio unit (RU) includes information on a resource area and user equipment (UE) identification information corresponding to a value indicating non-scheduling of the layer. It may include an operation of receiving a control plane (C-plane) message from a distributed unit (DU) through a fronthaul interface. The method may include calculating a beamforming weight based on the C-plane message. The method may include performing beamforming based on the beamforming weight.

According to one embodiment, the beamforming weight may be an arrangement for at least one layer scheduled in the resource region. The array may include weight values to be applied to IQ (in-phase and quadrature-phase) data in each layer. The size of the array may correspond to the number of the at least one layer. The at least one layer may not include the layer for which the non-scheduling is indicated.

According to one embodiment, the beamforming weight may be calculated based on channel information received from the DU.

According to one embodiment, the C-plane message may include section extension information for group configuration of multiple ports. The section extension information may include UE identification information for each of the additional layers. The additional layers include the layer for which the non-scheduling is indicated, and UE identification information for the layer may be included in the section extension information.

According to one embodiment, the UE identification information may include a ueId parameter for providing a label of the UE to which section content is applied. The ueId parameter is 15-bit, and the value indicating the non-scheduling may be 0x7FFF, 0x00FF, or a value set by M-plane.

In embodiments, a method performed by a distributed unit (DU) may include identifying non-scheduling for a layer in a resource area. The method includes generating a control plane (C-plane) message including information about the resource area and UE (user equipment) identification information corresponding to a value indicating the non-scheduling of the layer. may include. The method may include transmitting the generated C-plane message to a radio unit (RU). The C-plane message may be related to beamforming weight in the RU.

According to one embodiment, the beamforming weight may be an arrangement for at least one layer scheduled in the resource region. The array may include weight values to be applied to IQ (in-phase and quadrature-phase) data in each layer. The size of the array may correspond to the number of the at least one layer. The at least one layer may not include the layer for which the non-scheduling is indicated.

According to one embodiment, the method may include an operation of the at least one processor transmitting channel information to the RU. The channel information may be used for the beamforming weight.

According to one embodiment, the C-plane message may include section extension information for group configuration of multiple ports. The section extension information may include UE identification information for each of the additional layers. The additional layers include the layer for which the non-scheduling is indicated, and UE identification information for the layer may be included in the section extension information.

According to one embodiment, the UE identification information may include a ueId parameter for providing a label of the UE to which section content is applied. The ueId parameter is 15-bit, and the value indicating the non-scheduling may be 0x7FFF, 0x00FF, or a value set by M-plane.

The electronic device and method according to embodiments of the present disclosure can improve beamforming performance in the RU by indicating an unscheduled layer on the fronthaul interface.

The effects that can be obtained from the present disclosure are not limited to the effects mentioned above, and other effects not mentioned can be clearly understood by those skilled in the art from the description below. will be.

Methods according to embodiments described in the claims or specification of the present disclosure may be implemented in the form of hardware, software, or a combination of hardware and software.

When implemented as software, a computer-readable storage medium that stores one or more programs (software modules) may be provided. One or more programs stored in a computer-readable storage medium are configured to be executable by one or more processors in an electronic device (configured for execution). One or more programs include instructions that cause the electronic device to execute methods according to embodiments described in the claims or specification of the present disclosure.

These programs (software modules, software) may include random access memory, non-volatile memory, including flash memory, read only memory (ROM), and electrically erasable programmable ROM. (electrically erasable programmable read only memory, EEPROM), magnetic disc storage device, compact disc-ROM (CD-ROM), digital versatile discs (DVDs), or other types of disk storage. It can be stored in an optical storage device or magnetic cassette. Alternatively, it may be stored in a memory consisting of a combination of some or all of these. Additionally, multiple configuration memories may be included.

In addition, the program may be distributed through a communication network such as the Internet, an intranet, a local area network (LAN), a wide area network (WAN), or a storage area network (SAN), or a combination thereof. It may be stored on an attachable storage device that is accessible. This storage device can be connected to a device performing an embodiment of the present disclosure through an external port. Additionally, a separate storage device on a communications network may be connected to the device performing embodiments of the present disclosure.

In the specific embodiments of the present disclosure described above, elements included in the disclosure are expressed in singular or plural numbers depending on the specific embodiment presented. However, singular or plural expressions are selected to suit the presented situation for convenience of explanation, and the present disclosure is not limited to singular or plural components, and even components expressed in plural may be composed of singular or singular. Even expressed components may be composed of plural elements.

Meanwhile, in the detailed description of the present disclosure, specific embodiments have been described, but of course, various modifications are possible without departing from the scope of the present disclosure.

Claims (20)

In the electronic device of the RU (radio unit),
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,
A control plane (C-plane) message containing information about the resource area and UE (user equipment) identification information corresponding to a value to indicate non-scheduling of the layer is sent to a distributed unit (DU). ) is received through the fronthaul interface,
Calculate a beamforming weight based on the C-plane message,
Configured to perform beamforming based on the beamforming weight,
Electronic devices.
In claim 1,
The beamforming weight is an arrangement for at least one layer scheduled in the resource region,
The array includes weight values to be applied to IQ (in-phase and quadrature-phase) data in each layer,
The size of the array corresponds to the number of the at least one layer,
The at least one layer does not include the layer for which the non-scheduling is indicated,
Electronic devices.
In claim 1,
The beamforming weight is calculated based on channel information received from the DU,
Electronic devices.
In claim 1,
The C-plane message includes section expansion information for group configuration of multiple ports,
The section extension information includes UE identification information for each of the additional layers,
The additional layers include the layer for which the non-scheduling is indicated, and UE identification information for the layer is included in the section extension information.
Electronic devices.
In claim 1,
The UE identification information includes an ueId parameter to provide a label of the UE to which the section content applies,
The ueId parameter is 15-bit, and the value indicating the non-scheduling is 0x7FFF, 0x00FF, or a value set by M-plane,
Electronic devices.
In the electronic device of a distributed unit (DU),
at least one transceiver; and
Comprising at least one processor coupled to the at least one transceiver,
The at least one processor,
In the resource area, identify non-scheduling for the layer,
Generating a control plane (C-plane) message including information about the resource area and UE (user equipment) identification information corresponding to a value indicating the non-scheduling of the layer,
Configured to transmit the generated C-plane message to a radio unit (RU),
The C-plane message is related to the beamforming weight in the RU,
Electronic devices.
In claim 6,
The beamforming weight is an arrangement for at least one layer scheduled in the resource region,
The array includes weight values to be applied to IQ (in-phase and quadrature-phase) data in each layer,
The size of the array corresponds to the number of the at least one layer,
The at least one layer does not include the layer for which the non-scheduling is indicated,
Electronic devices.
In claim 6,
The at least one processor is further configured to transmit channel information to the RU,
The channel information is used for the beamforming weight,
Electronic devices.
In claim 6,
The C-plane message includes section expansion information for group configuration of multiple ports,
The section extension information includes UE identification information for each of the additional layers,
The additional layers include the layer for which the non-scheduling is indicated, and UE identification information for the layer is included in the section extension information.
Electronic devices.
In claim 6,
The UE identification information includes an ueId parameter to provide a label of the UE to which the section content applies,
The ueId parameter is 15-bit, and the value indicating the non-scheduling is 0x7FFF, 0x00FF, or a value set by M-plane,
Electronic devices.
In the method performed by a radio unit (RU),
A control plane (C-plane) message containing information about the resource area and UE (user equipment) identification information corresponding to a value to indicate non-scheduling of the layer is sent to a distributed unit (DU). ), an operation of receiving through the fronthaul interface,
An operation of calculating a beamforming weight based on the C-plane message,
Including an operation of performing beamforming based on the beamforming weight,
method.
In claim 11,
The beamforming weight is an arrangement for at least one layer scheduled in the resource region,
The array includes weight values to be applied to IQ (in-phase and quadrature-phase) data in each layer,
The size of the array corresponds to the number of the at least one layer,
The at least one layer does not include the layer for which the non-scheduling is indicated,
method.
In claim 11,
The beamforming weight is calculated based on channel information received from the DU,
method.
In claim 11,
The C-plane message includes section expansion information for group configuration of multiple ports,
The section extension information includes UE identification information for each of the additional layers,
The additional layers include the layer for which the non-scheduling is indicated, and UE identification information for the layer is included in the section extension information.
method.
In claim 11,
The UE identification information includes an ueId parameter to provide a label of the UE to which the section content applies,
The ueId parameter is 15-bit, and the value indicating the non-scheduling is 0x7FFF, 0x00FF, or a value set by M-plane,
method.
In the method performed by a distributed unit (DU),
In the resource area, an operation to identify non-scheduling for a layer;
Generating a control plane (C-plane) message including information about the resource area and UE (user equipment) identification information corresponding to a value indicating the non-scheduling of the layer;
Including transmitting the generated C-plane message to a radio unit (RU),
The C-plane message is related to the beamforming weight in the RU,
method.
In claim 16,
The beamforming weight is an arrangement for at least one layer scheduled in the resource region,
The array includes weight values to be applied to IQ (in-phase and quadrature-phase) data in each layer,
The size of the array corresponds to the number of the at least one layer,
The at least one layer does not include the layer for which the non-scheduling is indicated,
method.
In claim 16,
The at least one processor further includes transmitting channel information to the RU,
The channel information is used for the beamforming weight,
method.
In claim 16,
The C-plane message includes section expansion information for group configuration of multiple ports,
The section extension information includes UE identification information for each of the additional layers,
The additional layers include the layer for which the non-scheduling is indicated, and UE identification information for the layer is included in the section extension information.
method.
In claim 16,
The UE identification information includes an ueId parameter to provide a label of the UE to which the section content applies,
The ueId parameter is 15-bit, and the value indicating the non-scheduling is 0x7FFF, 0x00FF, or a value set by M-plane,
method.

Images