Base station and control method

Abstract

This base station includes a distribution unit and a radio unit. The distribution unit comprises: a reception unit that receives a channel state information report from the radio unit; a control unit that generates, on the basis of the channel state information report, codebook information including an index designating a codebook type, an index designating a space configuration, an index designating a compression scheme, and an index designating a codebook for a beamforming weight compressed using the compression scheme; and a transmission unit that transmits a control plane message including the codebook information to the radio unit.

Description

Base Station and Control Method

[0001] The present invention relates to a base station and a control method in a wireless communication system.

[0002] In a wireless communication system based on the 3GPP (registered trademark) standard, namely NR (New Radio) (also referred to as "5G") and a successor system of NR (e.g., "6G"), technologies that meet requirements such as a large-capacity system, high data transmission speed, low latency, simultaneous connection of a large number of terminals, low cost, power saving, etc. are being studied (e.g., Non-Patent Document 1).

[0003] In 5G, massive MIMO (Multiple Input Multiple Output) technology plays an important role in realizing high-speed and large-capacity communication. In massive MIMO, beamforming is performed using a large number of antenna elements to efficiently transmit signals to terminals. Here, in order to realize beamforming, a beamforming weight, which is a precoding matrix based on the channel state information of each terminal, is required.

[0004] Also, in the architecture of O-RAN (Open-Radio Access Network), the distributed unit (O-DU (Distribution Unit)) and the radio unit (O-RU (Radio Unit)) in the base station communicate via a fronthaul. In the existing specification, the beamforming weight calculated by the O-DU is transmitted to the O-RU by the control plane, and the O-RU executes beamforming using the beamforming.

[0005] 3GPP TS 38.300 V18.3.0 (2024-09) 3GPP TS 38.214 V18.3.0 (2024-09)

[0006] In large-scale massive MIMO systems, the sheer volume of beamforming weight data creates a problem that strains the fronthaul bandwidth between the distributed units (O-DUs) and the radio units (O-RUs). Therefore, O-RAN is considering the use of codebook-based dynamic beamforming (CDBF), where the O-DUs transmit codebook information, which contains less information than the beamforming weights, to the O-RUs.

[0007] However, in order to efficiently utilize the fronthaul bandwidth, it is necessary to transmit codebook information efficiently, but currently, O-RAN does not specify a method for transmitting codebook information from O-DU to O-RU using the CDBF method.

[0008] The present invention has been made in view of the above points, and aims to efficiently transmit codebook information from a distributed unit (O-DU) to a wireless unit (O-RU) in codebook-based beamforming.

[0009] According to the disclosed technology, a base station is provided, comprising a distributed unit and a radio unit, wherein the distributed unit includes a receiving unit that receives a channel status information report from the radio unit, a control unit that generates codebook information based on the channel status information report, including an index specifying a codebook type, an index specifying a spatial configuration, an index specifying a compression method, and an index specifying a codebook for beamforming weights compressed using the compression method, and a transmitting unit that transmits a control plane message including the codebook information to the radio unit.

[0010] According to the disclosed technology, codebook information in codebook-based beamforming can be efficiently transmitted from an O-DU to a radio unit (O-RU).

[0011] This figure shows an example configuration of a wireless communication system in an embodiment of the present invention (1). This figure shows an example configuration of a wireless communication system in an embodiment of the present invention (2). This figure shows an example of a logical architecture in O-RAN. This figure is for explaining a conventional beamforming method. This figure shows an example of a sequence diagram in an embodiment of the present invention. This figure shows an example of codebook information in an embodiment of the present invention (1). This figure is for explaining a wideband codebook in an embodiment of the present invention. This figure is for explaining a subband codebook in an embodiment of the present invention. This figure shows an example of codebook information in an embodiment of the present invention (2). This figure shows an example of an additional field in an embodiment of the present invention (1). This figure shows an example of an additional field in an embodiment of the present invention (2). This figure shows an example of the functional configuration of a base station 10 and a network node 30 in an embodiment of the present invention. This figure shows an example of the functional configuration of a terminal 20 in an embodiment of the present invention. This figure shows an example of the hardware configuration of a base station 10 and a terminal 20 in an embodiment of the present invention. This figure shows an example of the configuration of a vehicle 2001 in an embodiment of the present invention.

[0012] Embodiments of the present invention will be described below with reference to the drawings. Note that the embodiments described below are examples, and the embodiments to which the present invention applies are not limited to those described below.

[0013] In the operation of the wireless communication system according to the embodiment of the present invention, existing technologies may be used as appropriate. However, such existing technologies may be, for example, existing LTE or existing NR, but are not limited to existing LTE or NR.

[0014] Furthermore, in the embodiments of the present invention described below, terms such as SS (Synchronization signal), PSS (Primary SS), SSS (Secondary SS), PBCH (Physical broadcast channel), PRACH (Physical random access channel), PDCCH (Physical Downlink Control Channel), PDSCH (Physical Downlink Shared Channel), PUCCH (Physical Uplink Control Channel), and PUSCH (Physical Uplink Shared Channel), which are used in existing LTE systems, will be used. This is for convenience of description, and similar signals, functions, etc., may be called by other names. Also, the above terms in NR correspond to NR-SS, NR-PSS, NR-SSS, NR-PBCH, NR-PRACH, etc. However, even if a signal is used in NR, it is not necessarily explicitly stated as "NR-".

[0015] Furthermore, in the embodiments of the present invention, the duplex system may be a TDD (Time Division Duplex) system, an FDD (Frequency Division Duplex) system, or any other system (for example, a Flexible Duplex).

[0016] Furthermore, in embodiments of the present invention, "configuring" wireless parameters means that predetermined values ​​are pre-configured, or that wireless parameters notified from the base station 10 or terminal 20 are configured. Also, in the following description, " / " means "and / or" unless otherwise specified, or unless it is clear from the context that it has a different meaning.

[0017] Figure 1 shows an example configuration (1) of a wireless communication system according to an embodiment of the present invention. The wireless communication system according to an embodiment of the present invention includes a base station 10 and a terminal 20, as shown in Figure 1. Figure 1 shows one base station 10 and one terminal 20, but this is an example, and there may be multiple base stations 10 and terminals 20.

[0018] Base station 10 is a communication device that provides one or more cells and communicates wirelessly with terminal 20. The physical resources of the wireless signal are defined in the time domain and the frequency domain. The time domain may be defined by the number of OFDM (Orthogonal Frequency Division Multiplexing) symbols, and the frequency domain may be defined by the number of subcarriers or resource blocks. Base station 10 transmits synchronization signals and system information to terminal 20. Synchronization signals are, for example, NR-PSS and NR-SSS. System information is transmitted, for example, in NR-PBCH and is also called broadcast information. Synchronization signals and system information may also be called SSB (SS / PBCH block). As shown in Figure 1, base station 10 transmits control signals or data to terminal 20 via DL (Downlink) and receives control signals or data from terminal 20 via UL (Uplink). Both base station 10 and terminal 20 are capable of transmitting and receiving signals using beamforming. Furthermore, both the base station 10 and the terminal 20 can apply MIMO (Multiple Input Multiple Output) communication to DL or UL. Also, both the base station 10 and the terminal 20 may communicate via Carrier Aggregation (CA) through secondary cells (SCell) and primary cells (PCell). Additionally, the terminal 20 may communicate via Dual Connectivity (DC) through the primary cell of base station 10 and the primary secondary cell group cell (PSCell) of another base station 10.

[0019] Terminal 20 is a communication device equipped with wireless communication capabilities, such as a smartphone, mobile phone, tablet, wearable device, or M2M (Machine-to-Machine) communication module. As shown in Figure 1, Terminal 20 receives control signals or data from the base station 10 via DL and transmits control signals or data to the base station 10 via UL, thereby utilizing various communication services provided by the wireless communication system. Terminal 20 also receives various reference signals transmitted from the base station 10 and performs propagation path quality measurement based on the reception results of said reference signals.

[0020] Furthermore, various requirements are being considered for the next generation of 6G. For example, these requirements may include ultra-broadband communication, mission-critical communication, ultra-massive connection, universal coverage, intelligent connection, and ubiquitous sensing.

[0021] Furthermore, these requirements may include ultra-high-speed communication, large-capacity communication, ultra-wide coverage, ultra-low power consumption, low cost, ultra-low latency, ultra-high reliability communication, ultra-high connectivity, and sensing.

[0022] To meet these requirements, the new concept aims for extensibility (e.g., making it more effective for future use), ease of operation, customizability (e.g., making it easier to operate), and sustainability (e.g., cost reduction, a more robust configuration, and resilience). Furthermore, guaranteed communication, ensuring a minimum level of performance at all times, is being considered.

[0023] Figure 2 shows an example configuration (2) of a wireless communication system according to an embodiment of the present invention. Figure 2 shows an example configuration of a wireless communication system when DC (Dual connectivity) is performed. As shown in Figure 2, a base station 10A that will be an MN (Master Node) and a base station 10B that will be an SN (Secondary Node) are provided. Base stations 10A and 10B are each connected to the core network. Terminal 20 can communicate with both base station 10A and base station 10B.

[0024] A cell group provided by base station 10A, which is an MN (Mobile Network), is called an MCG (Master Cell Group), and a cell group provided by base station 10B, which is an SN (Mobile Network), is called an SCG (Secondary Cell Group). In a data center, an MCG consists of one PCell and one or more SCells, and an SCG consists of one PSCell (Primary SCG Cell) and one or more SCells.

[0025] Figure 3 shows an example of the logical architecture in O-RAN. As shown in Figure 3, at base station 10, distributed units (O-DUs) and radio units (O-RUs) are connected via an open fronthaul interface (which may also be simply called a fronthaul interface). This interface transmits and receives control signals, user data, and synchronization signals in the Open FH CUS-Plane, and management signals in the Open FH M-Plane. Furthermore, the Service Management and Orchestration (SMO), which manages and integrates services, communicates with the O-RUs via the Open FH M-Plane, with the O-DUs via the O1 interface, and with the O-Cloud via the O2 interface. Furthermore, in SMO, the non-real-time control unit (Non-RT (Real Time) RIC (RAN Intelligent Controller)) communicates with the near-real-time control unit (Near-RT (Real Time) RIC) via the A1 interface. The control plane (O-CU-CP) and user plane (O-CU-UP) of the O-CU (Central Unit) communicate with the O-DU via the F1-c and F1-u interfaces, respectively. The Near-RT RIC communicates with the O-DU and O-CU-CP, etc., via the E2 interface.

[0026] O-DU, O-CU, O-RU, SMO, and RIC may be deployed on the same base station, on different base stations, or in different locations other than base stations (nearby, remote, etc.). They may be treated as base station equipment or as network nodes. Furthermore, O-DU and O-CU may be deployed on a virtualization infrastructure and may be denoted as vDU (virtual DU) and vCU (virtual CU), for example.

[0027] Figure 4 is a diagram illustrating a conventional beamforming method. As shown in Figure 4, in a conventional beamforming method, the O-DU performs SRS channel estimation based on the SRS (Sounding Reference Signal) received from the O-RU, and calculates the beamforming weight (BFW) based on the estimated SRS channel information. Next, the O-DU transmits the calculated BFW to the O-RU via the fronthaul between the O-DU and the O-RU using the control plane signal.

[0028] In a massive MIMO (Multiple Input Multiple Output) environment, the sheer volume of BFW data becomes a problem, as it strains the fronthaul bandwidth. To address this, O-RAN is considering the use of Codebook-based Dynamic Beamforming (CDBF), which transmits codebook information (which contains less information than the beamforming weights) from the O-DU to the O-RU. However, in order to efficiently utilize the fronthaul bandwidth, it is necessary to transmit the codebook information efficiently, but currently, O-RAN does not specify a method for transmitting codebook information from the O-DU to the O-RU using the CDBF method.

[0029] (Example) This example describes a procedure for efficiently transmitting codebook information from an O-DU to a radio unit (O-RU) in codebook-based beamforming. Here, in the sequence diagram, requests / instructions / notifications / reports transmitted and received by the O-DU and O-RU may be messages that include requests / instructions / notifications / reports. Furthermore, multiple methods shown in the example and its modifications may be used in combination.

[0030] (Example 1) Example 1 describes a procedure for storing and transmitting codebook information in codebook-based beamforming in a control plane message between the O-DU and O-RU. Figure 5 is a diagram showing an example of a sequence diagram in an embodiment of the present invention. The processing of each step will be described below.

[0031] S101: O-DU10A sends an instruction to O-RU10B to transmit a Channel State Information - Reference Signal (CSI-RS).

[0032] S102: O-RU10B transmits a channel status information reference signal (CSI-RS) to terminal 20 in response to the transmission instruction received in S101.

[0033] S103: Terminal 20 uses the channel status information reference signal (CSI-RS) received in S102 to perform channel estimation and generates a channel status information report (CSI Report) that includes a Rank Indicator (RI) and a Pre-coding Matrix Indicator (PMI) indicating the transmission rank in MIMO (see Non-Patent Document 2).

[0034] S104: Terminal 20 sends the generated channel status information report (CSI Report) to O-RU10B.

[0035] S105: O-RU10B transmits the channel status information report (CSI Report) received in S104 to O-DU10A.

[0036] S106: Based on the channel status information report (CSI Report) received in S105, the O-DU10A selects the optimal cobook type and spatial configuration.

[0037] S107: Based on the information selected in S106, O-DU10A determines the index of the codebook, and generates codebook information including the index and the like. Here, the codebook information may be generated, for example, by expanding the control plane message of the existing specification and setting information related to the codebook in the newly defined section extension (section extension) area.

[0038] FIG. 6 is a diagram showing an example (1) of codebook information in an embodiment of the present invention. As shown in FIG. 6, the structure of the section extension including the codebook information defines the field name and size (unit: bit).

[0039] extType is information indicating the type of the section extension, and a newly defined value (ZZ) indicating codebook information is set.

[0040] extLen indicates the length of the extension (in bytes).

[0041] codebookTypeIndex is an index for specifying the codebook type, and may be, for example, an index indicating codebook types such as Type I and Type II defined in Section 5.2.2.2 of Non-Patent Document 2. Type I may be a type for single-user MIMO, and Type II may be a type for multi-user MIMO.

[0042] spacialConfigIndex is an index for specifying the spatial configuration.

[0043] rankIndicator is a rank indicator.

[0044] reserved is a reserved area for future use and the like.

[0045] codebookIndex1 is an index of the wideband codebook (details will be described later).

[0046] The subbandSize is the size of the subband (in units of PRB (Physical Resource Block)).

[0047] The codebookIndex2 is the index of the subband codebook (details will be described later).

[0048] The portToAntennaMapping is the mapping information between the CSI-RS port and the antenna.

[0049] The padding is the bits padded to align the extension to a 4-byte boundary.

[0050] Here, in the codebook information, both codebookIndex1 and codebookIndex2 may be included, or only one of them may be included. O-DU10A may determine the rankIndicator based on the RI included in the CSI Report. O-DU10A may determine codebookIndex1 / codebookIndex2 based on the PMI included in the CSI Report.

[0051] FIG. 7 is a diagram for explaining the wideband codebook in the embodiment of the present invention. The index (codebookTypeIndex1) of the wideband codebook shown in FIG. 6 is an index that specifies the codebook for the precoding matrix (i.e., BFW) applied to the entire band. In FIG. 7, as an example, it is assumed that the wideband codebook includes an index for entry 0 corresponding to the precoding matrix with the beam indicating the left direction and an index for entry 1 corresponding to the precoding matrix with the beam indicating the right direction.

[0052] O-DU10A evaluates the channel state based on the channel state information report (CSI Report) received from the terminal 20 and determines the direction of the optimal beam (i.e., entry 0 or entry 1). Further, for example, when O-DU10A selects entry 0, it sets "0" in codebookindex1, and when it selects entry 1, it sets "1" in codebookindex1.

[0053] Figure 8 is a diagram illustrating a subband codebook in an embodiment of the present invention. The subband codebook index (codebookTypeIndex2) shown in Figure 6 divides the entire bandwidth into multiple subbands and includes an index that specifies the codebook corresponding to the precoding matrix applied to each subband. The subband codebook index (codebookTypeIndex2) may be used, for example, when frequency-selective fading is present. In Figure 8, as an example, an index corresponding to the precoding matrix indicating the beam direction is assigned to each subband into which the entire bandwidth is divided. Here, the index is configured to include an index for entry 0, which corresponds to the precoding matrix indicating the beam is pointing to the left, and an index for entry 1, which corresponds to the precoding matrix indicating the beam is pointing to the right. Based on the channel status information report (CSI Report) received from terminal 20, O-DU10A evaluates the channel status and determines the optimal beam direction (i.e., entry 0 or entry 1) for subband 0, which is the frequency band of the first half, and subband 1, which is the frequency band of the second half. For example, codebookindex2 may be written as [index for subband 0 (0 or 1), index for subband 1 (0 or 1)]. Also, for example, if O-DU10A selects entry 0 for subband 0 and entry 1 for subband 1, codebookindex2 will be set to [0, 1]. Note that the number of entries (2) and the number of subbands (2) are just examples, and values ​​of 3 or more are also possible.

[0054] Based on the channel status information report (CSI Report) received from terminal 20, O-DU10A evaluates the channel status and determines the optimal beam direction (i.e., entry 0 or entry 1) for each subband. Furthermore, for example, if O-DU10A selects entry 0 in subband 0 and entry 1 in subband 1, it sets codebookindex2 to [0, 1].

[0055] Let's return to the sequence diagram in Figure 5 and explain.

[0056] S108: O-DU10A sends a control plane message to O-RU10B containing the codebook information generated in S107. Here, the control plane message may include information (ef bit) in the message header indicating that it contains a section extension.

[0057] S109: O-RU10B obtains the information necessary for calculating the beamforming weight from the codebook information received in S108 and calculates the beamforming weight.

[0058] Here, for example, O-RU10B may identify the codebook type and spatial configuration to be used based on the codebookTypeIndex and spatialConfigIndex included in the codebook information. O-RU10B may also calculate beamforming weights for each subband using codebookIndex1 and codebookIndex2 included in the codebook information. Furthermore, O-RU10B may perform mapping from the CSI-RS port to the antenna using the portToAntennaMapping information included in the codebook information.

[0059] S110: O-RU10B may perform control related to communication with terminal 20 by CDBF by applying the beamforming weight calculated in S109 to the user plane data and performing beamforming.

[0060] The following describes variations of the embodiments. Multiple variations may be applied in combination.

[0061] (Modification 1-1) Utilization of existing specification section extensions O-DU10A may set the codebook information in an area that extends a section extension defined in the existing specification (e.g., section extension 10) in the control plane message. In addition, O-DU10A may appropriately set the position / length of the fields in the section extension in order to maintain compatibility with the existing specification.

[0062] Figure 9 shows an example (1) of codebook information in an embodiment of the present invention. As shown in Figure 9, a field (cdbfFlag) containing a flag indicating the use of CDBF (for example, set to 1 when used) and a field (codebookinfo) containing CDBF codebook information are added to a section extension defined in the existing specifications (for example, section extension 10, etc.) as information indicating fields for CDBF (Codebook-based Dynamic Beamforming).

[0063] In S107 of Figure 5, O-DU10A may set the index of the determined codebook in the aforementioned field (codebookinfo) which has been added to the section extension defined in the existing specification. Here, information other than the codebook index may be set in the field of the section extension defined in the existing specification, or it may be set in a field that has been added in the same way as the field containing the CDBF codebook information (codebookinfo).

[0064] (Modification 1-2) Capability information regarding codebook types and spatial configurations O-RU10B may, for example, after the startup of the base station 10, transmit capability information to O-DU10A, including information regarding the codebook types supported by O-RU10B (codebook-types-supported) and information regarding the spatial configuration (cdbf-spatial-configs-supported), for example, using a message in the management plane (M-plane).

[0065] Furthermore, in S106 of Figure 5, O-DU10A may select the optimal codebook type and spatial configuration based on the channel status information report (CSI Report) received in S105 and the capability information received from O-RU10B, and then determine the codebook index in S107.

[0066] (Modification 1-3) Configuration information regarding the codebook types and spatial configurations to be used O-DU10A may send configuration information to O-RU10B, including information regarding the codebook types used in O-RU10B (codebook-types-used) and information regarding the spatial configuration (cdbf-spatial-configs-used), for example, using a message on the management plane (M-plane).

[0067] Furthermore, O-DU10A may use the capability information described in Modification Example 2 to select, for example, the codebook type and spatial configuration to be used from among the codebook types and spatial configurations supported by O-RU10B, and then set the configuration information.

[0068] (Modification 1-4) Efficiency improvement for BFW calculation The O-RU10B may perform BFW calculation using an FPGA (Field Programmable Gate Array) / DSP (Digital Signal Processor).

[0069] O-RU10B may cache previously calculated BWFs and reuse the cached BWFs for the same codebook information.

[0070] The O-RU10B may use a multi-core processor / GPU (Graphics Processing Unit) to simultaneously perform BFW calculations for multiple terminals / subbands.

[0071] (Example 2) Example 2 describes a procedure for performing information compression on codebook information in codebook-based beamforming, and then storing and transmitting the compressed codebook information in a control plane message between O-DU10A and O-RU10B.

[0072] O-DU10A and O-RU10B may be assumed to specify the compression method used when compressing the codebook information in the section extension containing codebook information, as described in Example 1. This section extension may be a newly defined section extension for sending and receiving codebook information, as shown in Figure 6, or it may be an existing section extension that has been extended for sending and receiving codebook information, as shown in Modification 1-1.

[0073] Figure 10 shows an example (1) of an additional field in an embodiment of the present invention. As shown in Figure 10, a field (compressionMethod) specifying the compression method used when compressing codebook information may be added, for example, to the section extension containing codebook information shown in Figure 6. Here, the wideband codebook index (codebookindex1) and subband codebook index (codebookindex2) in Figure 6 become codebook indexes compressed by the specified compression method.

[0074] Furthermore, the compression method may be specified in the compressionMethod field using 3 bits, as shown below. For example, if 000 is specified, the codebook index will not be compressed. • 000: No compression • 001: Differential coding • 010: Run-length coding • 011: Huffman coding • 100: Arithmetic coding

[0075] Furthermore, O-RU10B may, for example, after the startup of base station 10, transmit capability information regarding the codebook information compression methods supported by O-RU10B to O-DU10A, for example, using a management plane (M-plane) message. For example, such capability information may include a parameter (supportedCompressionMethods) that declares a list of compression methods (compressionMethod) supported by O-RU10B.

[0076] Based on the capability information received from O-RU10B, O-DU10A may determine the compression method to use and send information about the compression method to O-RU10B, for example, using a message in the management plane (M-plane). For example, if O-RU10B only supports run-length coding as a capability, O-DU10A may select run-length coding. Alternatively, if O-RU10B supports multiple compression methods as a capability, O-DU10A may determine the compression method based on the priority of compression methods set in O-DU10A / O-RU10B. The correspondence between the 3-bit value of the compression method and the specific compression method may be declared to O-RU10B via M-Plane or similar prior to operation, so that O-DU10A and O-RU10B have a common understanding. Furthermore, when changing the compression method indicated by the 3 bits of the compressionMethod, or when supporting a new compression method, the O-DU10A and O-RU10B may share the same configuration information by notifying the O-RU10B again of the compression method correspondence. Similarly, the compression level (compressionLevel), which will be described later, may also be shared after the change.

[0077] (Example 3) Example 3 describes a procedure for storing and transmitting codebook information from multiple terminals in a control plane message.

[0078] O-DU10A and O-RU10B may assume that a section extension containing codebook information includes codebook information for multiple terminals. Here, the section extension may be a newly defined section extension for sending and receiving codebook information, as shown in Figure 6, or it may be an existing section extension that has been extended for sending and receiving codebook information, as shown in Modification 1-1. Furthermore, O-DU10A and O-RU10B may determine multiple terminals to which codebook information will be sent collectively based on channel status information (CSI) reports received from multiple terminals.

[0079] Figure 11 shows an example (2) of additional fields in an embodiment of the present invention. As shown in Figure 11, a field specifying the number of terminals to transmit codebook information in bulk (numOfUEs), information common to multiple terminals (commonInfo), and information different for each terminal (ueSpecificInfo) may be added to the section extension containing codebook information, as shown in Figure 6.

[0080] commonInfo may include, for example, the following information: • compressionMethod: The compression method used in common across all devices • codebookType: The codebook type used in common across all devices Also, ueSpecificInfo may include, for example, the following information: Here, there are corresponding codebookIndex1 and codebookindex2 for each ueID. • ueID: Device identifier • codebookIndex1: Compressed wideband codebook index • codebookIndex2: Compressed subband codebook index

[0081] (Variation 3-1) O-DU10A and O-RU10B may assume that compression is performed on the entire ueSpecificInfo, including, for example, uncompressed codebook indexes (codebookindex1 / codebookindex2), rather than on each codebook index. Alternatively, O-DU10A and O-RU10B may assume that the ueSpecificInfo contains information that is compressed collectively for all terminals' codebookindex1 and information that is compressed collectively for all terminals' codebookindex2.

[0082] (Variation 3-2) In addition to Variation 3-1, O-DU10A and O-RU10B may assume that compression is performed on the entire ueSpecificInfo, including the uncompressed codebook indexes (codebookindex1 / codebookindex2) for multiple consecutive time points. Alternatively, O-DU10A and O-RU10B may assume that the ueSpecificInfo contains information obtained by compressing the codebookindex1 of all terminals together for multiple consecutive time points, and information obtained by compressing the codebookindex2 of all terminals together.

[0083] (Modification 3-3) In Example 3, Modification 3-1, and Modification 3-2, O-DU10A and O-RU10B may assume that the codebook index (codebookindex1 / codebookindex2) is not compressed when transmitting codebook information from multiple terminals in a batch. Here, information indicating no compression (e.g., 000) may be specified in the field specifying the compression method (compressionMethod), or the field specifying the compression method may not be included in the section extension.

[0084] (Modification 3-4) O-DU10A and O-RU10B may be configured to notify the identifiers of multiple terminals and the value of the codebook index (codebookindex1 / codebookindex2) if the codebook index (codebookindex1 / codebookindex2) is the same value for multiple terminals. In other words, instead of notifying the codebook index (codebookindex1 / codebookindex2) for each terminal, it may be configured to notify the identifiers of multiple terminals and the value of a single codebook index (codebookindex1 / codebookindex2). This makes it possible to compress the codebook index information to be notified.

[0085] (Example 4) Example 4 describes the procedure for adjusting the compression ratio and other parameters when compressing codebook information.

[0086] (Example 4-1) Addition of Compression Parameters O-DU10A and O-RU10B may be assumed to include compression parameters in their section extensions for sending and receiving codebook information, specifying settings for the compression method, such as a compression level indicating the strength of the compression. For example, in a certain compression method (e.g., Huffman coding), the compression level may be an integer value from 0 to 9, where a higher value indicates a higher compression ratio. O-RU10B can appropriately restore (decompress) the compressed codebook information based on the value set for the parameter.

[0087] Furthermore, O-RU10B may, for example, after the startup of base station 10, transmit capability information regarding the compression levels supported by O-RU10B to O-DU10A, for example, using a management plane (M-plane) message. For example, this capability information may include a parameter (supportedCompressionLevels) that declares the range / list of compression levels supported by O-RU10B. For example, the range / list of compression levels supported by O-RU10B may be a continuous value from 0 to 9, or a list of discrete values ​​such as [0,2,5,9]. Also, O-DU10B may notify O-DU10A of the range / list of compression levels set according to the network's operational requirements / hardware capabilities using M-Plane. This allows O-DU10A to dynamically select a compression level and notify O-RU10B of the selected compression level in a section extension.

[0088] Furthermore, regarding the combination of compression method and compression level, the supported compression levels for each compression method may be declared in a table or similar format. For example, when O-RU10B reports capability information to O-DU10A using M-Plane, it may indicate combinations such as "supports compressionLevel=0 to 5 for Huffman coding (compressionMethod=011b)" and "supports compressionLevel=6 to 9 for arithmetic coding (100b)". This allows O-DU10A and O-RU10B to correctly understand the correspondence between compression method and compression level.

[0089] (Example 4-2) Dynamic change of compression ratio according to network conditions The O-DU10A may monitor the network bandwidth / latency conditions and adaptively change the compression method / compression level, etc. For example, if the network is congested, the O-DU10A may select a compression method with a higher compression ratio (e.g., Huffman coding or arithmetic coding). Also, if the network is not congested, the O-DU10A may reduce the compression ratio to reduce the processing load on the O-RU10B.

[0090] (Example 4-3) Coordination between O-DU10A and O-RU10B O-DU10A may dynamically adjust the compression method / compression level according to the network conditions (such as congestion) and notify O-RU10B by including the adjusted settings in the section extension related to the codebook information.

[0091] O-RU10B may perform beamforming weight (BFW) calculations using the decompressed codebook information based on the compression method and compression level included in the received section extension.

[0092] (Example 4-4) Introduction of a compression algorithm using machine learning O-DU10A and O-RU10B may perform highly efficient compression and decompression of codebook information using a pre-shared machine learning model. In addition, O-DU10A and O-RU10B may periodically update the parameters of the machine learning model in order to maintain the accuracy / efficiency of compression and decompression.

[0093] (Examples 4-5) Data volume reduction by optimizing the bit size of the codebook index O-DU10A and O-RU10B may reduce the amount of data by dynamically adjusting the bit size of the codebook index (e.g., codebookindex1 / codebookindex2) according to the network conditions (e.g., congestion). O-DU10A and O-RU10B may also assume that the section extension for codebook information includes a field (bitWidth) indicating the bit size of the codebook index (e.g., codebookindex1 / codebookindex2). O-DU10A and O-RU10B may also assume that if the value of the codebook index (codebookindex1 / codebookindex2) does not change from the value transmitted last time, a bit indicating that it has not changed is transmitted instead. For example, 0 may be transmitted as the bit indicating that it has not changed, and the codebook index may always be a bit sequence that starts with 1. Furthermore, O-DU10A and O-RU10B may assume that the difference between the previously transmitted value and the value of the codebook index (codebookindex1 / codebookindex2) will be transmitted. For example, if the difference is 2 bits or less (e.g., -1,0,1,2), the amount of data may be reduced by notifying the difference. In this case, information indicating that it is a difference notification may also be sent to O-RU10B.

[0094] (Example 4-6) Combination of Compression Methods O-DU10A and O-RU10B may use a combination of multiple compression methods (e.g., differential coding and Huffman coding) to achieve a high compression ratio. For example, O-DU10A may notify O-RU10B of information regarding the two types of compression methods to be used, and information indicating that the two types of compression methods will be used in combination. In addition, O-DU10A and O-RU10B may use an algorithm that automatically selects the optimal compression method according to the characteristics of the codebook information.

[0095] (Example 4-7) Error Detection / Correction O-DU10A and O-RU10B may assume that a parity bit or CRC is added to the compressed codebook information. Alternatively, O-DU10A and O-RU10B may assume that an error correction algorithm (e.g., Hamming code, Reed-Solomon code) is applied to the compressed codebook information. This enables error detection and correction, thereby improving the reliability of data transmission.

[0096] (Effects) In the above-described embodiment / modification, it is possible to reduce the bandwidth usage of the fronthaul by compressing the codebook information, transmitting the codebook information to multiple terminals in a batch, and adjusting the compression ratio adaptively. In other words, it is possible to efficiently transmit the codebook information in codebook-based beamforming from the distributed unit (O-DU10A) to the wireless unit (O-RU10B).

[0097] (Device Configuration) Next, an example of the functional configuration of the base station 10, network node 30, and terminal 20 that perform the processing and operations described above will be explained. The base station 10, network node 30, and terminal 20 include the functions to perform the embodiments described above. However, the base station 10, network node 30, and terminal 20 may each be equipped with only some of the functions in the embodiments.

[0098] <Base Station 10 and Network Node 30> Figure 12 shows an example of the functional configuration of a base station 10 and a network node 30. As shown in Figure 12, the base station 10 has a transmitting unit 110, a receiving unit 120, a setting unit 130, and a control unit 140. The functional configuration shown in Figure 12 is merely an example. The functional classifications and names of the functional units can be anything as long as they can perform the operations according to the embodiment of the present invention. The network node 30 may have the same functional configuration as the base station 10. Furthermore, a network node 30 having multiple different functions on the system architecture may be composed of multiple network nodes 30 separated by function.

[0099] The transmitting unit 110 includes the function of generating a signal to be transmitted to the terminal 20 or other network node 30 and transmitting the signal by wire or wireless. The receiving unit 120 includes the function of receiving various signals transmitted from the terminal 20 or other network node 30 and obtaining information from the received signal, for example, information from a higher layer. A communication unit including the transmitting unit 110 and the receiving unit 120 may be configured.

[0100] The setting unit 130 stores pre-configured setting information and various setting information to be transmitted to the terminal 20 in a storage device, and reads them from the storage device as needed.

[0101] The control unit 140 performs the processing described in the embodiment. The signal transmission function in the control unit 140 may be included in the transmission unit 110, and the signal reception function in the control unit 140 may be included in the reception unit 120.

[0102] Furthermore, the base station 10 may include a distributed unit (O-DU), a radio unit (O-RU), and a central unit (O-CU). Also, the SMO, the non-real-time control device (Non-RT RIC) in the SMO, and the near-real-time control device (Near-RT RIC) may be functions of the network node 30. In addition, the O-DU, O-RU, O-CU, SMO, Non-RT RIC, and Near-RT RIC may each have a transmitting unit 110, a receiving unit 120, a setting unit 130, and a control unit 140, and the transmitting unit 110 and the receiving unit 120 may communicate with each other.

[0103] <Terminal 20> Figure 13 is a diagram showing an example of the functional configuration of terminal 20. As shown in Figure 13, terminal 20 has a transmitting unit 210, a receiving unit 220, a setting unit 230, and a control unit 240. The functional configuration shown in Figure 13 is merely an example. The names of the functional categories and functional units can be anything as long as they can perform the operations according to the embodiment of the present invention. In addition, the communication device that becomes the resource holder may have a functional configuration similar to that of terminal 20.

[0104] The transmitting unit 210 creates a transmission signal from the transmission data and transmits the transmission signal wirelessly. The receiving unit 220 wirelessly receives various signals and obtains signals from higher layers from the received physical layer signals. The receiving unit 220 also has the function of receiving NR-PSS, NR-SSS, NR-PBCH, DL / UL control signals or reference signals transmitted from the network node 30. A communication unit including the transmitting unit 210 and the receiving unit 220 may be configured.

[0105] The setting unit 230 stores various setting information received from the network node 30 by the receiving unit 220 in its storage device and reads it from the storage device as needed. The setting unit 230 also stores pre-configured setting information.

[0106] The control unit 240 performs the processing described in the embodiment. The signal transmission function in the control unit 240 may be included in the transmission unit 210, and the signal reception function in the control unit 240 may be included in the reception unit 220.

[0107] (Hardware Configuration) The block diagrams (Figures 12 and 13) used in the description of the above embodiments show functional units. These functional blocks (components) are realized by any combination of at least one of hardware and software. Furthermore, the method of realizing each functional block is not particularly limited. That is, each functional block may be realized using one device that is physically or logically coupled, or it may be realized using two or more physically or logically separated devices that are directly or indirectly connected (for example, using wired or wireless connections). A functional block may be realized by combining the above one device or the above multiple devices with software.

[0108] Functions include, but are not limited to, judgment, decision, determination, calculation, calculation, processing, derivation, investigation, exploration, confirmation, reception, transmission, output, access, resolution, selection, selection, establishment, comparison, assumption, expectation, assumption, broadcasting, notifying, communicating, forwarding, configuring, reconfiguring, allocating (mapping), and assigning. For example, a functional block (configuration part) that enables transmission is called a transmitting unit or transmitter. In all cases, as mentioned above, the method of implementation is not particularly limited.

[0109] For example, the network node 30, terminal 20, etc. in one embodiment of the present disclosure may function as a computer that processes the wireless communication method of the present disclosure. Figure 14 is a diagram showing an example of the hardware configuration of a base station 10 and terminal 20 according to one embodiment of the present disclosure. The network node 30 may have the same hardware configuration as the base station 10. The above-mentioned base station 10 and terminal 20 may be physically configured as a computer device including a processor 1001, a storage device 1002, an auxiliary storage device 1003, a communication device 1004, an input device 1005, an output device 1006, a bus 1007, etc.

[0110] In the following explanation, the term "device" can be read as "circuit," "device," "unit," etc. The hardware configuration of the base station 10 and terminal 20 may include one or more of the devices shown in the figure, or it may be configured without some of the devices.

[0111] Each function in the base station 10 and terminal 20 is realized by loading predetermined software (programs) onto hardware such as the processor 1001 and storage device 1002, which allows the processor 1001 to perform calculations, control communication by the communication device 1004, and control at least one of data reading and writing in the storage device 1002 and auxiliary storage device 1003.

[0112] The processor 1001 controls the entire computer, for example, by running an operating system. The processor 1001 may consist of a central processing unit (CPU) that includes interfaces with peripheral devices, control devices, arithmetic units, registers, etc. For example, the control unit 140, control unit 240, etc., described above may be implemented by the processor 1001.

[0113] Furthermore, the processor 1001 reads programs (program code), software modules, or data from at least one of the auxiliary storage device 1003 and the communication device 1004 into the storage device 1002, and executes various processes accordingly. The program used is one that causes the computer to execute at least a part of the operations described in the above embodiment. For example, the control unit 140 of the base station 10 shown in Figure 12 may be implemented by a control program stored in the storage device 1002 and operated by the processor 1001. Also, for example, the control unit 240 of the terminal 20 shown in Figure 13 may be implemented by a control program stored in the storage device 1002 and operated by the processor 1001. Although the above-described processes have been explained as being executed by one processor 1001, they may be executed simultaneously or sequentially by two or more processors 1001. The processor 1001 may be implemented by one or more chips. The program may also be transmitted from the network via a telecommunications line.

[0114] The storage device 1002 is a computer-readable recording medium and may consist of at least one of the following: ROM (Read Only Memory), EPROM (Erasable Programmable ROM), EEPROM (Electrically Erasable Programmable ROM), RAM (Random Access Memory), etc. The storage device 1002 may also be called a register, cache, main memory, etc. The storage device 1002 can store executable programs (program code), software modules, etc., for implementing a communication method according to one embodiment of the present disclosure.

[0115] The auxiliary storage device 1003 is a computer-readable recording medium and may consist of at least one of the following: an optical disc such as a CD-ROM (Compact Disc ROM), a hard disk drive, a flexible disk, a magneto-optical disk (e.g., a compact disk, a digital multipurpose disk, a Blu-ray® disk), a smart card, flash memory (e.g., a card, a stick, a key drive), a floppy® disk, a magnetic strip, etc. The above-mentioned storage medium may also be a database, server, or other suitable medium that includes at least one of the storage device 1002 and the auxiliary storage device 1003.

[0116] The communication device 1004 is hardware (transmitting / receiving device) for communicating between computers via at least one of a wired network and a wireless network, and is also referred to as a network device, network controller, network card, communication module, etc. The communication device 1004 may be configured to include, for example, a high-frequency switch, duplexer, filter, frequency synthesizer, etc., in order to implement at least one of frequency division duplex (FDD) and time division duplex (TDD). For example, the transmitting and receiving antenna, amplifier section, transmitting and receiving section, transmission path interface, etc., may be implemented by the communication device 1004. The transmitting and receiving section may be implemented in a physically or logically separated manner, with a transmitting section and a receiving section.

[0117] The input device 1005 is an input device that accepts input from an external source (e.g., a keyboard, mouse, microphone, switch, button, sensor, etc.). The output device 1006 is an output device that outputs to an external source (e.g., a display, speaker, LED lamp, etc.). The input device 1005 and the output device 1006 may be configured as an integrated unit (e.g., a touch panel).

[0118] Furthermore, each device, such as the processor 1001 and the storage device 1002, is connected by a bus 1007 for communicating information. The bus 1007 may be configured using a single bus, or different buses may be configured for each device.

[0119] Furthermore, the base station 10 and terminal 20 may be configured to include hardware such as a microprocessor, a digital signal processor (DSP), an ASIC (Application Specific Integrated Circuit), a PLD (Programmable Logic Device), and an FPGA (Field Programmable Gate Array), and some or all of each functional block may be realized by such hardware. For example, the processor 1001 may be implemented using at least one of these hardware components.

[0120] Figure 15 shows an example of the configuration of vehicle 2001. As shown in Figure 15, vehicle 2001 includes an operating unit 2002, a steering unit 2003, an accelerator pedal 2004, a brake pedal 2005, a shift lever 2006, front wheels 2007, rear wheels 2008, an axle 2009, an electronic control unit 2010, various sensors 2021 to 2029, an information service unit 2012, and a communication module 2013. Each aspect / embodiment described in this disclosure may be applied to a communication device mounted on vehicle 2001, for example, to the communication module 2013.

[0121] The operating unit 2002 consists of, for example, an engine, a motor, or a hybrid of an engine and a motor. The steering unit 2003 includes at least a steering wheel (also called a handle) and is configured to steer at least one of the front wheels and the rear wheels based on the operation of the steering wheel, which is operated by the user.

[0122] The electronic control unit 2010 consists of a microprocessor 2031, memory (ROM, RAM) 2032, and communication ports (IO ports) 2033. Signals from various sensors 2021 to 2029 installed in the vehicle 2001 are input to the electronic control unit 2010. The electronic control unit 2010 may also be called an ECU (Electronic Control Unit).

[0123] Signals from various sensors 2021 to 2029 include current signals from current sensor 2021 for sensing motor current, front and rear wheel rotation speed signals acquired by rotation speed sensor 2022, front and rear wheel air pressure signals acquired by air pressure sensor 2023, vehicle speed signals acquired by vehicle speed sensor 2024, acceleration signals acquired by acceleration sensor 2025, accelerator pedal depression signals acquired by accelerator pedal sensor 2029, brake pedal depression signals acquired by brake pedal sensor 2026, shift lever operation signals acquired by shift lever sensor 2027, and detection signals acquired by object detection sensor 2028 for detecting obstacles, vehicles, pedestrians, etc.

[0124] The Information Service Unit 2012 consists of various devices for providing (outputting) various types of information such as driving information, traffic information, and entertainment information, including a car navigation system, audio system, speakers, television, and radio, and one or more ECUs that control these devices. The Information Service Unit 2012 uses information acquired from external devices via a communication module 2013, etc., to provide various multimedia information and multimedia services to the occupants of the vehicle 2001. The Information Service Unit 2012 may include input devices that accept input from the outside (e.g., keyboard, mouse, microphone, switch, button, sensor, touch panel, etc.) and output devices that perform output to the outside (e.g., display, speaker, LED lamp, touch panel, etc.).

[0125] The driver assistance system unit 2030 consists of various devices that provide functions to prevent accidents or reduce the driver's workload, such as millimeter-wave radar, LiDAR (Light Detection and Ranging), cameras, positioning locators (e.g., GNSS), map information (e.g., high-definition (HD) maps, autonomous vehicle (AV) maps), gyro systems (e.g., IMU (Inertial Measurement Unit), INS (Inertial Navigation System)), AI (Artificial Intelligence) chips, and AI processors, as well as one or more ECUs that control these devices. The driver assistance system unit 2030 also transmits and receives various information via the communication module 2013 to realize driver assistance functions or autonomous driving functions.

[0126] The communication module 2013 can communicate with the microprocessor 2031 and components of the vehicle 2001 via its communication port. For example, the communication module 2013 sends and receives data via the communication port 2033 between the moving parts 2002, steering parts 2003, accelerator pedal 2004, brake pedal 2005, shift lever 2006, front wheels 2007, rear wheels 2008, axle 2009, the microprocessor 2031 and memory (ROM, RAM) 2032 in the electronic control unit 2010, and sensors 2021-29 provided in the vehicle 2001.

[0127] The communication module 2013 is a communication device that can be controlled by the microprocessor 2031 of the electronic control unit 2010 and can communicate with external devices. For example, it can send and receive various types of information with external devices via wireless communication. The communication module 2013 may be located either inside or outside the electronic control unit 2010. The external device may be, for example, a base station or a mobile station.

[0128] The communication module 2013 may transmit at least one of the following to an external device via wireless communication: signals from the various sensors 2021-2028 input to the electronic control unit 2010, information obtained based on said signals, and information based on input from an external source (user) obtained via the information service unit 2012. The electronic control unit 2010, the various sensors 2021-2028, the information service unit 2012, etc., may also be called input units that accept input. For example, the PUSCH transmitted by the communication module 2013 may include the information based on the above input.

[0129] The communication module 2013 receives various information (traffic information, signal information, inter-vehicle information, etc.) transmitted from an external device and displays it on the information service unit 2012 provided in the vehicle 2001. The information service unit 2012 may also be called an output unit, which outputs information (for example, outputs information to devices such as displays and speakers based on the PDSCH (or data / information decoded from the PDSCH) received by the communication module 2013). The communication module 2013 also stores the various information received from the external device in a memory 2032 that can be used by the microprocessor 2031. Based on the information stored in the memory 2032, the microprocessor 2031 may control the operating unit 2002, steering unit 2003, accelerator pedal 2004, brake pedal 2005, shift lever 2006, front wheels 2007, rear wheels 2008, axles 2009, sensors 2021-2029, etc., provided in the vehicle 2001.

[0130] <Notes> (Note 1) A base station comprising a distributed unit and a radio unit, wherein the distributed unit comprises: a receiving unit that receives a channel status information report from the radio unit; a control unit that generates codebook information including an index specifying a codebook type, an index specifying a spatial configuration, an index specifying a compression method, and an index specifying a codebook for beamforming weights compressed using the compression method; and a transmitting unit that transmits a control plane message including the codebook information to the radio unit. (Note 2) A base station comprising a distributed unit and a radio unit, wherein the distributed unit comprises: a receiving unit that receives a channel status information report from each terminal from the radio unit; a control unit that generates codebook information including the number of terminals of a plurality of terminals to which codebook information is transmitted collectively, common information common to the plurality of terminals, and an index specifying a codebook for beamforming weights for each of the plurality of terminals; and a transmitting unit that transmits a control plane message including the codebook information to the radio unit. (Note 3) The base station according to Note 2, wherein the common information includes information specifying a compression method for compressing the index that specifies the codebooks for the beamforming weights. (Note 4) The base station according to Note 1 or Note 2, wherein the index that specifies the codebooks for the beamforming weights includes at least one of: an index that specifies the codebooks for beamforming weights across the entire band and an index that specifies the codebooks for beamforming weights for each subband. (Note 5) The base station according to Note 1 or Note 2, wherein the control unit adjusts the bit size of the index that specifies the codebooks for the beamforming weights according to the degree of network congestion.(Appendix 6) A control method performed by a base station including a distributed unit and a radio unit, comprising: receiving a channel status information report from the radio unit; generating codebook information based on the channel status information report, including an index specifying a codebook type; an index specifying a spatial configuration; an index specifying a compression method; an index specifying a codebook for beamforming weights compressed using the compression method; and transmitting a control plane message including the codebook information to the radio unit.

[0131] Any of the above appendices enables efficient transmission of codebook information from the distributed unit (O-DU) to the radio unit (O-RU) in codebook-based beamforming.

[0132] (Supplement to Embodiments) Embodiments of the present invention have been described above, but the disclosed invention is not limited to such embodiments, and those skilled in the art will understand various modifications, alterations, alternatives, substitutions, etc. Specific numerical examples have been used to facilitate understanding of the invention, but unless otherwise specified, these numerical values ​​are merely examples, and any appropriate values ​​may be used. The division of items in the above description is not essential to the present invention, and matters described in two or more items may be combined as needed, and matters described in one item may be applied to matters described in another item (as long as they do not contradict each other). The boundaries of functional units or processing units in the functional block diagram do not necessarily correspond to the boundaries of physical parts. The operation of multiple functional units may be physically performed by one part, or the operation of one functional unit may be physically performed by multiple parts. The processing procedures described in the embodiments may be rearranged as long as they do not contradict each other. For the convenience of explaining the processing, the base station 10 and terminal 20 have been described using functional block diagrams, but such devices may be realized in hardware, software, or a combination thereof. The software operated by the processor of the base station 10 according to an embodiment of the present invention and the software operated by the processor of the terminal 20 according to an embodiment of the present invention may be stored in any suitable storage medium such as random access memory (RAM), flash memory, read-only memory (ROM), EPROM, EEPROM, register, hard disk (HDD), removable disk, CD-ROM, database, server, or other appropriate storage medium.

[0133] Furthermore, notification of information is not limited to the embodiments described herein and may be carried out by other means. For example, notification of information may be carried out by physical layer signaling (e.g., DCI (Downlink Control Information), UCI (Uplink Control Information)), upper layer signaling (e.g., RRC (Radio Resource Control) signaling, MAC (Medium Access Control) signaling), broadcast information (MIB (Master Information Block), SIB (System Information Block)), other signals, or combinations thereof. Also, RRC signaling may be called RRC messages, and may be, for example, RRC Connection Setup messages, RRC Connection Reconfiguration messages, etc.

[0134] Each aspect / embodiment described in this disclosure refers to LTE (Long Term Evolution), LTE-A (LTE-Advanced), SUPER 3G, IMT-Advanced, 4G (4th generation mobile communication system), 5G (5th generation mobile communication system), 6th generation mobile communication system (6G), xth generation mobile communication system (xG) (xG (where x is, for example, an integer or decimal)), FRA (Future Radio Access), NR (new Radio), New radio access (NX), Future generation radio access (FX), W-CDMA (registered trademark), GSM (registered trademark), CDMA2000, UMB (Ultra Mobile Broadband), IEEE 802.11 (Wi-Fi (registered trademark)), IEEE 802.16 (WiMAX (registered trademark)), IEEE 802.20 may apply to at least one system utilizing UWB (Ultra-WideBand), Bluetooth®, or other appropriate systems, and to next-generation systems extended, modified, created, or defined based thereon. Alternatively, multiple systems may be applied in combination (e.g., a combination of at least one of LTE and LTE-A with 5G).

[0135] The processing procedures, sequences, flowcharts, etc., of each aspect / embodiment described herein may be reordered, provided they are consistent with each other. For example, the methods described herein present various step elements in an exemplary order and are not limited to that specific order.

[0136] In this specification, specific operations performed by the base station 10 may, in some cases, be performed by its upper node. In a network consisting of one or more network nodes having a base station 10, it is clear that various operations performed for communication with the terminal 20 can be performed by the base station 10 and at least one of the other network nodes (for example, an MME or S-GW, but not limited to these). Although the above example illustrates the case where there is one other network node besides the base station 10, the other network node may be a combination of multiple other network nodes (for example, an MME and an S-GW).

[0137] The information or signals described in this disclosure may be output from a higher layer (or lower layer) to a lower layer (or higher layer). They may also be input and output via multiple network nodes.

[0138] Input and output information may be stored in a specific location (e.g., memory) or managed using a management table. Input and output information may be overwritten, updated, or appended to. Output information may be deleted. Input information may be transmitted to other devices.

[0139] The determination in this disclosure may be made by a value represented by one bit (0 or 1), by a Boolean value (true or false), or by a numerical comparison (for example, a comparison with a predetermined value).

[0140] Software should be broadly interpreted to mean instructions, instruction sets, code, code segments, program code, programs, subprograms, software modules, applications, software applications, software packages, routines, subroutines, objects, executable files, execution threads, procedures, functions, and so on, whether they are called software, firmware, middleware, microcode, hardware description languages, or by any other name.

[0141] Furthermore, software, instructions, information, etc., may be transmitted and received via a transmission medium. For example, if software is transmitted from a website, server, or other remote source using at least one of wired technology (such as coaxial cable, fiber optic cable, twisted pair, or digital subscriber line (DSL)) and wireless technology (such as infrared or microwave), then at least one of these wired and wireless technologies is included in the definition of a transmission medium.

[0142] The information, signals, etc. described in this disclosure may be represented using any of the various different techniques. For example, the data, instructions, commands, information, signals, bits, symbols, chips, etc. that may be referred to throughout the above description may be represented by voltage, current, electromagnetic waves, magnetic fields or magnetic particles, optical fields or photons, or any combination thereof.

[0143] In addition, terms used in this disclosure and terms necessary for understanding this disclosure may be replaced with terms having the same or similar meanings. For example, at least one of the channel and symbol may be a signal (signaling). Also, a signal may be a message. Furthermore, a component carrier (CC) may be called a carrier frequency, cell, frequency carrier, etc.

[0144] The terms “system” and “network” as used in this disclosure are interchangeable.

[0145] Furthermore, the information, parameters, etc., described in this disclosure may be expressed using absolute values, relative values ​​from a given value, or other corresponding information. For example, wireless resources may be indicated by an index.

[0146] The names used for the parameters described above are not restrictive in any way. Furthermore, the formulas and other expressions using these parameters may differ from those expressly disclosed in this disclosure. Various channels (e.g., PUCCH, PDCCH, etc.) and information elements can be identified by any suitable name, and therefore, the various names assigned to these various channels and information elements are not restrictive in any way.

[0147] In this disclosure, terms such as "Base Station (BS)", "wireless base station", "base station equipment", "fixed station", "NodeB", "eNodeB (eNB)", "gNodeB (gNB)", "access point", "transmission point", "reception point", "transmission / reception point", "cell", "sector", "cell group", "carrier", and "component carrier" may be used interchangeably. Base stations may also be referred to by terms such as macrocell, small cell, femtocell, and picocell.

[0148] A base station can accommodate one or more (e.g., three) cells. If a base station accommodates multiple cells, the entire coverage area of ​​the base station can be divided into multiple smaller areas, each of which may also be provided with communication services by a base station subsystem (e.g., a Remote Radio Head (RRH)). The terms “cell” or “sector” refer to part or all of the coverage area of ​​at least one of the base station and / or base station subsystems that provide communication services in that coverage.

[0149] In this disclosure, the transmission of information by a base station to a terminal may be interpreted as the base station instructing the terminal to perform control or operation based on the information.

[0150] In this disclosure, terms such as "Mobile Station (MS)," "user terminal," "User Equipment (UE)," and "terminal" may be used interchangeably.

[0151] A mobile station may also be referred to by those skilled in the art as a subscriber station, mobile unit, subscriber unit, wireless unit, remote unit, mobile device, wireless device, wireless communication device, remote device, mobile subscriber station, access terminal, mobile terminal, wireless terminal, remote terminal, handset, user agent, mobile client, client, or several other appropriate terms.

[0152] At least one of the base station and the mobile station may be called a transmitting device, a receiving device, a communication device, etc. At least one of the base station and the mobile station may also be a device mounted on a mobile body, the mobile body itself, etc. The mobile body refers to a movable object, and its speed of movement is arbitrary. This also includes the case when the mobile body is stationary. The mobile body includes, but is not limited to, vehicles, transport vehicles, automobiles, motorcycles, bicycles, connected cars, excavators, bulldozers, wheel loaders, dump trucks, forklifts, trains, buses, handcarts, rickshaws, ships and other watercraft, airplanes, rockets, satellites, drones (registered trademark), multicopters, quadcopters, balloons, and items mounted on them. The mobile body may also be a mobile body that moves autonomously based on operation commands. It may be a vehicle (e.g., a car, an airplane, etc.), an unmanned mobile body (e.g., a drone, an autonomous vehicle, etc.), or a robot (manned or unmanned). Furthermore, at least one of the base station and the mobile station may include devices that do not necessarily move during communication operations. For example, at least one of the base station and the mobile station may be an IoT (Internet of Things) device such as a sensor.

[0153] Furthermore, the term "base station" in this disclosure may be interpreted as "user terminal." For example, the various aspects / embodiments of this disclosure may be applied to a configuration in which communication between a base station and a user terminal is replaced with communication between multiple terminals 20 (which may be called, for example, D2D (Device-to-Device), V2X (Vehicle-to-Everything), etc.). In this case, the terminals 20 may have the functions that the base station 10 has. Also, terms such as "uplink" and "downlink" may be interpreted as terms corresponding to terminal-to-terminal communication (for example, "side"). For example, uplink channel, downlink channel, etc., may be interpreted as side channel.

[0154] Similarly, the term "user terminal" in this disclosure may be replaced with "base station." In this case, the base station may be configured to have the same functions as the user terminal described above.

[0155] As used in this disclosure, the terms “determining” and “determining” may encompass a wide variety of actions. “Determining” may include, for example, judging, calculating, computing, processing, deriving, investigating, looking up, searching, or inquiring (e.g., searching in a table, database, or other data structure), or ascertaining. “Determining” may also include receiving (e.g., receiving information), transmitting (e.g., sending information), inputting, outputting, or accessing (e.g., accessing data in memory). Furthermore, "judgment" and "decision" can include considering something as having been "judged" or "decided" after resolving, selecting, choosing, establishing, comparing, etc. In other words, "judgment" and "decision" can include considering something as having been "judged" or "decided" after some action. Also, "judgment (decision)" can be reinterpreted as "assuming," "expecting," or "considering."

[0156] The terms “connected,” “coupled,” or any variation thereof, mean any direct or indirect connection or coupling between two or more elements, and may include the presence of one or more intermediate elements between two elements that are “connected” or “coupled” with each other. The coupling or connection between elements may be physical, logical, or a combination thereof. For example, “connection” may be reinterpreted as “access.” As used in this disclosure, two elements may be considered to be “connected” or “coupled” with each other using at least one of one or more wires, cables, and printed electrical connections, and, in some non-limiting and non-exclusive examples, electromagnetic energy having wavelengths in the radio frequency domain, microwave domain, and optical (both visible and invisible) domain.

[0157] The reference signal can also be abbreviated as RS (Reference Signal), and may be called a pilot depending on the applicable standard.

[0158] In this disclosure, the phrase "based on" does not mean "based solely on" unless otherwise specified. In other words, the phrase "based on" means both "based solely on" and "based at least on."

[0159] Any reference to elements using the designations “first,” “second,” etc., as used in this disclosure does not generally limit the quantity or order of those elements. These designations may be used in this disclosure as a convenient way to distinguish between two or more elements. Accordingly, references to the first and second elements do not imply that only two elements may be employed, or that the first element must precede the second element in any way.

[0160] In the configuration of each of the above devices, "means" may be replaced with "part," "circuit," "device," etc.

[0161] Where the terms “include,” “including,” and variations thereof are used in this disclosure, these terms are intended to be inclusive, as is the term “comprising.” Furthermore, the term “or” as used in this disclosure is not intended to mean exclusive OR.

[0162] In this disclosure, if articles are added through translation, such as a, an, and the in English, this disclosure may include the fact that the noun following these articles is plural.

[0163] In this disclosure, the term "A and B are different" may mean "A and B are different from each other." The term may also mean "A and B are each different from C." Terms such as "separate" and "combine" may be interpreted similarly to "different."

[0164] Each aspect / embodiment described in this disclosure may be used individually, in combination, or switched between as needed during implementation. Furthermore, notification of specific information (e.g., notification that "X is") is not limited to explicit notification, but may also be implicit (e.g., by not providing such notification).

[0165] Although the present disclosure has been described in detail above, it will be clear to those skilled in the art that the present disclosure is not limited to the embodiments described herein. The present disclosure can be implemented in modified and altered forms without departing from the intent and scope of the present disclosure as defined by the claims. Therefore, the descriptions in the present disclosure are illustrative and not intended to be restrictive in any way.

[0166] 10 Base station 110 Transmitter 120 Receiver 130 Setting unit 140 Control unit 20 Terminal 210 Transmitter 220 Receiver 230 Setting unit 240 Control unit 30 Network node 1001 Processor 1002 Storage device 1003 Auxiliary storage device 1004 Communication device 1005 Input device 1006 Output device

Claims

1. A base station comprising a distributed unit and a radio unit, wherein the distributed unit includes: a receiving unit that receives a channel status information report from the radio unit; a control unit that generates codebook information based on the channel status information report, including: an index that specifies a codebook type; an index that specifies a spatial configuration; an index that specifies a compression method; and an index that specifies a codebook for beamforming weights compressed using the compression method; and a transmitting unit that transmits a control plane message including the codebook information to the radio unit.

2. A base station comprising a distributed unit and a radio unit, wherein the distributed unit includes: a receiving unit that receives channel status information reports from each terminal from the radio unit; a control unit that generates codebook information including the number of terminals of a plurality of terminals to which codebook information is transmitted collectively based on the channel status information reports; common information that is common among the plurality of terminals; and an index that specifies a codebook for the beamforming weight of each of the plurality of terminals; and a transmitting unit that transmits a control plane message including the codebook information to the radio unit.

3. The base station according to claim 2, wherein the common information includes information specifying a compression method for compressing an index that specifies a codebook for the beamforming weights.

4. The base station according to claim 1 or 2, wherein the index specifying the codebook for the beamforming weights includes at least one of: an index specifying the codebook for beamforming weights across the entire bandwidth; and an index specifying the codebook for beamforming weights for each subband.

5. The base station according to claim 1 or 2, wherein the control unit adjusts the bit size of the index that specifies the codebook for the beamforming weight according to the degree of network congestion.

6. A control method performed by a base station including a distributed unit and a radio unit, comprising: receiving a channel status information report from the radio unit; generating codebook information based on the channel status information report, including an index specifying a codebook type; an index specifying a spatial configuration; an index specifying a compression method; an index specifying a codebook for beamforming weights compressed using the compression method; and transmitting a control plane message including the codebook information to the radio unit.

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