KR20230071674A - Apparatus and method for power saving of fronthaul transmission in wireless communication system - Google Patents

Abstract

The present disclosure relates to a 5^th generation (5G) or pre-5G communication system for supporting a higher data transmission rate after a 4^th generation (4G) communication system, such as long-term evolution (LTE). According to embodiments of the present invention, an apparatus of a distributed unit (DU) in a wireless communication system comprises: a transmitter; and one or more processors engaged with the transmitter. The one or more processors can be configured to identify whether there is no downlink scheduling information and an uplink scheduling information on a designated slot, and, if there is no downlink scheduling information and no uplink scheduling information on the designated slot, identify a segment where there is no downlink control plane (C-plane) message, no uplink C-plane message, and no downlink user plane (U-plane) message, and generate a control signal for turning off the power of the transmitter of the DU within the segment.

Description

APPARATUS AND METHOD FOR POWER SAVING OF FRONTHAUL TRANSMISSION IN WIRELESS COMMUNICATION SYSTEM

The present disclosure relates generally to wireless communication systems, and more particularly to apparatuses and methods for power saving in fronthaul transmission in wireless communication systems.

Efforts are being made to develop an improved 5th generation ( ^5G ) communication system or a pre-5G communication system in order to meet the growing demand for wireless data traffic after the commercialization of a 4th generation (4G ⁾ communication system. For this reason, the 5G communication system or the pre-5G communication system is called a beyond 4G network communication system or a long term evolution (LTE) system and a post LTE system.

In order to achieve a high data rate, implementation of the 5G communication system in an ultra-high frequency band is being considered. In order to mitigate the path loss of radio waves and increase the propagation distance of radio waves in the ultra-high frequency band, beamforming, massive multi-input multi-output (MIMO), and full-dimensional multi-input multi-output are used in 5G communication systems. (full dimensional MIMO, FD-MIMO), array antenna, analog beam-forming, and large scale antenna technologies are being discussed.

In addition, to improve the network of the system, in the 5G communication system, an evolved small cell, an advanced small cell, a cloud radio access network (cloud RAN), and an ultra-dense network , device to device communication (D2D), wireless backhaul, moving network, cooperative communication, coordinated multi-points (CoMP), and interference cancellation etc. are being developed.

In addition, in the 5G system, FQAM (hybrid frequency shift keying and quadrature amplitude modulation) and SWSC (sliding window superposition coding), which are advanced coding modulation (ACM) methods, and FBMC (filter bank multi carrier), an advanced access technology ), non-orthogonal multiple access (NOMA), and sparse code multiple access (SCMA) are being developed.

As transmission capacity increases in a wireless communication system, function split that functionally separates base stations is being applied. According to the functional separation, the base station can be divided into a digital unit (DU) and a radio unit (RU), and a front haul for communication between the DU and RU is defined, and transmission through the front haul is required . A method for reducing unnecessary power waste in fronthaul transmission between DUs and RUs is required.

Based on the above discussion, the present disclosure proposes an apparatus and method for power saving in an O (open)-radio access network (RAN)-based fronthaul interface in a wireless communication system.

In addition, the present disclosure proposes an apparatus and method for turning power off and on based on scheduling information of a distributed unit (DU) in an O-RAN based fronthaul interface in a wireless communication system.

In addition, the present disclosure proposes an apparatus and method for turning power off and on based on scheduling information of a distributed unit (RU) in an O-RAN based fronthaul interface in a wireless communication system.

According to embodiments of the present disclosure, a method performed by a distributed unit (DU) in a wireless communication system includes a process of identifying whether there is no downlink scheduling information and uplink scheduling information for a designated slot, and in the designated slot , when there is no downlink scheduling information and uplink scheduling information, a downlink control plane (C-plane) message, an uplink control plane message, and a downlink user plane (U-plane) It may include identifying a section without a message and generating a control signal for turning off the power of the transmitter of the DU within the section.

According to embodiments of the present disclosure, a method performed by a radio unit (RU) includes a process of identifying whether there is no uplink scheduling information for a designated slot, and a process for identifying whether there is no uplink scheduling information for the designated slot In this case, it may include identifying a section in which there is no uplink user plane (U-plane) message and generating a control signal for turning off the power of the transmitter of the RU in the section.

According to embodiments of the present disclosure, an apparatus of a distributed unit (DU) in a wireless communication system includes a transmitter and at least one processor coupled to the transmitter, and the at least one processor comprises a downlink for a designated slot. It identifies whether there is no link scheduling information and uplink scheduling information, and if there is no downlink scheduling information and uplink scheduling information for the designated slot, a downlink control plane (C-plane) message, uplink It may be configured to identify a section without a link control plane message and a downlink user plane (U-plane) message, and generate a control signal for powering off the transmitter of the DU within the section.

According to embodiments of the present disclosure, an apparatus of a radio unit (RU) in a wireless communication system includes a transmitter and at least one processor coupled to the transmitter, and the at least one processor includes an uplink for a designated slot. Identify whether there is no link scheduling information, identify a section in which there is no uplink user plane (U-plane) message when there is no uplink scheduling information for the designated slot, and within the section, the RU It can be configured to generate a control signal to power off the transmitter of the.

An apparatus and method according to embodiments of the present disclosure enable efficient power saving by turning power off and on based on scheduling information in an O-RAN based fronthaul interface.

An apparatus and method according to embodiments of the present disclosure enable efficient power saving by turning power off and on for a section in which neither a control plane message nor a user plane message is transmitted in a wireless communication system.

In addition, the effects obtainable through this document are not limited to the effects mentioned above, and other effects not mentioned will become clear to those skilled in the art from the description below. can be understood

1A illustrates a wireless communication system according to various embodiments of the present disclosure.
1B illustrates an example of a fronthaul structure according to functional separation of base stations according to various embodiments of the present disclosure.
2 illustrates a configuration of a digital unit (DU) according to various embodiments of the present disclosure.
3 illustrates a configuration of a radio unit (RU) according to various embodiments of the present disclosure.
4 shows an example of function splitting.
5A illustrates a scheduling scenario in an O-RAN based fronthaul interface according to embodiments of the present disclosure.
5B illustrates an example of a base station structure in an O-RAN based fronthaul interface according to embodiments of the present disclosure.
6 illustrates examples of protocol structures of messages in an O-RAN based fronthaul interface according to embodiments of the present disclosure.
7 illustrates an example of a structure of an O-DU (O-RAN DU) in an O-RAN based fronthaul interface according to an embodiment of the present disclosure.
8 illustrates an example of information input to a power saving device and an output signal in an O-RAN based fronthaul interface according to embodiments of the present disclosure.
9 illustrates an example of a transmission period of a control plane message and a user plane message in an O-RAN based fronthaul interface according to an embodiment of the present disclosure.
10 illustrates an example of a power saving period in an O-RAN based fronthaul interface according to embodiments of the present disclosure.
11 is a flowchart for power saving in a power saving device in an O-RAN based fronthaul interface according to an embodiment of the present disclosure.
12 is a flowchart for power saving in a power saving device of a DU in an O-RAN based fronthaul interface according to an embodiment of the present disclosure.
13 is a flowchart for power saving in a power saving device of an RU in an O-RAN based fronthaul interface according to an embodiment of the present disclosure.
In connection with the description of the drawings, the same or similar reference numerals may be used for the same or similar elements.

Terms used in the present disclosure are only used to describe a specific embodiment, and may not be intended to limit the scope of other embodiments. Singular expressions may include plural expressions unless the context clearly dictates otherwise. Terms used herein, including technical or scientific terms, may have the same meaning as commonly understood by one of ordinary skill in the art described in this disclosure. Among the terms used in the present disclosure, terms defined in general dictionaries may be interpreted as having the same or similar meanings as those in the context of the related art, and unless explicitly defined in the present disclosure, ideal or excessively formal meanings. not be 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 access method is described as an example. However, since various embodiments of the present disclosure include technology using both hardware and software, various embodiments of the present disclosure do not exclude software-based access methods.

Terms used in the following description to indicate signals (e.g., message, information, preamble, signal, signaling, sequence, stream), and terms indicating paths (e.g., port) . slot), subframe, radio frame, subcarrier, RE (resource element), RB (resource block), BWP (bandwidth part), opportunity), operation state Terminology (e.g. step, operation, procedure), term referring to data (e.g. packet, user stream, information, bit, symbol, codeword) (codeword)), term referring to channel, term referring to control information (e.g., downlink control information (DCI), medium access control control element (MAC CE), radio resource control (RRC) signaling), network object (network object) Entities), terms referring to components of a device, and the like are illustrated for convenience of description. Accordingly, the present disclosure is not limited to the terms described below, and other terms having equivalent technical meanings may be used.

In addition, in the present disclosure, an expression of more 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 more or less description not to exclude Conditions described as 'above' may be replaced with 'exceeds', conditions described as 'below' may be replaced with 'below', and conditions described as 'above and below' may be replaced with 'above and below'.

In addition, the present disclosure provides various embodiments using terms used in some communication standards (eg, 3rd Generation Partnership Project (3GPP), extensible radio access network (xRAN), and open)-radio access network (ORAN). However, this is only an example for explanation Various embodiments of the present disclosure can be easily modified and applied to other communication systems.

In the present disclosure, a 'slot' may have different meanings depending on a supported communication system. In the NR communication system, 'slot' refers to 14 symbols (or group of symbols). Unlike the NR communication system, the 3GPP standard of LTE refers to 7 symbols for 'slot'. A 'slot' in GSM is a time slot, and 8 time slots correspond to one timed division multiplexing access (TDMA) frame. In other words, the meaning of a slot may be different depending on the communication system. For example, in an LTE communication system, a “slot” has a correlation with an LTE “transmission time interval (TTI)” defined by 3GPP.

1A illustrates a wireless communication system according to various embodiments of the present disclosure. 1 illustrates a base station 110, a terminal 120, and a terminal 130 as some of nodes using a radio channel in a wireless communication system. Although FIG. 1 shows only one base station, other base stations identical or similar to the base station 110 may be further included.

Base station 110 is a network infrastructure that provides wireless access to terminals 120 and 130 . The base station 110 has coverage defined as a certain geographical area based on a distance over which signals can be transmitted. The base station 110 includes 'access point (AP)', 'eNodeB (eNB)', '5G node (5th generation node)', 'next generation nodeB (next generation nodeB)' in addition to the base station. , gNB)', 'wireless point', 'transmission/reception point (TRP)', or other terms having equivalent technical meaning.

Each of the terminal 120 and terminal 130 is a device used by a user and communicates with the base station 110 through a radio channel. A link from the base station 110 to the terminal 120 or terminal 130 is downlink (DL), and a link from the terminal 120 or terminal 130 to the base station 110 is uplink (UL) ) is referred to as Also, the terminal 120 and the terminal 130 may perform communication through a mutual wireless channel. In this case, a device-to-device link (D2D) between the terminal 120 and the terminal 130 is referred to as a sidelink, and the sidelink may be used interchangeably with the PC5 interface. In some cases, at least one of the terminal 120 and the terminal 130 may be operated without user involvement. That is, at least one of the terminal 120 and the terminal 130 is a device that performs machine type communication (MTC) and may not be carried by a user. Each of the terminal 120 and the terminal 130 includes 'user equipment (UE)', 'customer premises equipment' (CPE), 'mobile station', and 'subscription' other than the terminal. 'subscriber station', 'remote terminal', 'wireless terminal', 'electronic device', or 'user device' or any other term having an equivalent technical meaning. term can be referred to.

The base station 110, the terminal 120, and the terminal 130 may perform beamforming. The base station and the terminal can transmit and receive radio signals in a relatively low frequency band (eg, frequency range 1 (FR1) of NR). In addition, the base station and the terminal can transmit and receive radio signals in a relatively high frequency band (eg, FR2 of NR, mmWave band (eg, 28 GHz, 30 GHz, 38 GHz, 60 GHz)). In some embodiments, the base station 110 may perform communication with the terminal 110 within a frequency range corresponding to FR1. In some embodiments, the base station may perform communication with the terminal 120 within a frequency range corresponding to FR2. At this time, in order to improve the channel gain, the base station 110, the terminal 120, and the terminal 130 may perform beamforming. Here, beamforming may include transmit beamforming and receive beamforming. That is, the base station 110, the terminal 120, and the terminal 130 may give directivity to a transmitted signal or a received signal. To this end, the base station 110 and the terminals 120 and 130 may select serving beams through a beam search or beam management procedure. After the serving beams are selected, communication may be performed through a resource having a QCL relationship with a resource transmitting the serving beams.

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

In FIG. 1A, it is shown that both the base station and the terminal perform beamforming, but various embodiments of the present disclosure are not necessarily limited thereto. In some embodiments, a UE may or may not perform beamforming. Also, the base station may or may not perform beamforming. That is, only one of the base station and the terminal may perform beamforming, or both the base station and the terminal may not perform beamforming.

Although the base station 110, terminal 120, and terminal 130 are exemplified in FIG. 1A, embodiments of the present disclosure may also be applied to an integrated access and backhaul (IAB) node as a newly introduced relay node. The base station-related description described in this disclosure may be applied to a DU of an IAB node, and the terminal-related description described in this disclosure may be applied to a mobile terminal (MT) of an IAB node in the same or similar manner.

In the present disclosure, a beam refers to a spatial flow of a signal in a radio 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 analog beamforming and digital beamforming (eg, precoding). Reference signals transmitted based on beamforming include, for example, a demodulation-reference signal (DM-RS), a channel state information-reference signal (CSI-RS), and a synchronization signal/physical broadcast channel (SS/PBCH). , may include a sounding reference signal (SRS). In addition, as a configuration for each reference signal, an IE such as a CSI-RS resource or an SRS-resource may be used, and this configuration may include information associated with a beam. Beam-related information refers to whether a corresponding configuration (eg, CSI-RS resource) uses the same spatial domain filter as another configuration (eg, another CSI-RS resource within the same CSI-RS resource set) or different It may mean whether a spatial domain filter is used, or which reference signal is quasi-co-located (QCL), and if so, what type (eg, QCL type A, B, C, or D).

Conventionally, in a communication system in which the cell radius of a base station is relatively large, each base station includes a digital processing unit (or DU (digital unit)) and a radio frequency (RF) processing unit (RF processing unit, or RU (radio unit)). It was installed to include the functions of unit)). However, as a high frequency band is used in 4G ( ^4th generation) and/or later communication systems and the cell radius of base stations decreases, the number of base stations to cover a specific area increases, and it is difficult to install the increased base stations. The burden of installation costs on business operators has 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 geographically distributed RUs are deployed to cover a specific area structure has been proposed. Hereinafter, arrangement structures and extension examples of base stations according to various embodiments of the present disclosure are described with reference to FIG. 1B.

1B illustrates an example of a fronthaul structure according to functional separation of base stations according to various embodiments of the present disclosure. Unlike backhaul between a base station and a core network, fronthaul refers to between entities between a wireless LAN and a base station. 1B shows an example of a fronthaul structure between DU 160 and one RU 180, but this is only for convenience of description and the present disclosure is not limited thereto. In other words, an embodiment of the present disclosure may also be applied to a fronthaul structure between one DU and a plurality of RUs. For example, an embodiment of the present disclosure may be applied to a fronthaul structure between one DU and two RUs. In addition, an embodiment of the present disclosure may be applied to a fronthaul structure between one DU and three RUs.

Referring to FIG. 1B, the base station 110 may include a DU 160 and an RU 180. The fronthaul 170 between the DU 160 and the RU 180 may be operated through an F _x interface. For operation of the fronthaul 170 between the DU 160 and the RU 180, interfaces such as eCPRI (enhanced common public radio interface) and ROE (radio over ethernet) may be used.

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

The DU 160 may be in charge of higher layer functions of a wireless network. For example, the DU 160 may perform a function of a MAC layer and a part of a PHY layer. Here, a 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), layer mapping (layer mapping) (or layer demapping). According to an embodiment, when the DU 160 complies with the O-RAN standard, it may be referred to as an O-DU (O-RAN DU). The DU 160 may be replaced with a first network entity for a base station (eg, gNB) in embodiments of the present disclosure, if necessary.

The RU 180 may be in charge of lower layer functions of a wireless network. For example, the RU 180 may perform part of a PHY layer and an RF function. Here, part of the PHY layer is performed at a relatively lower level than the DU 160 among the functions of the PHY layer. For example, IFFT conversion (or FFT conversion), CP insertion (CP removal), digital beamforming can include An example of this specific functional separation is detailed in FIG. 4 . The RU 180 includes an 'access unit (AU)', an 'access point (AP)', a 'transmission/reception point (TRP)', and a 'remote radio head (RRH)'. ) ', 'radio unit (RU)' or other terms having equivalent technical meaning. According to one embodiment, when the RU 180 complies with the O-RAN standard, it may be referred to as an O-RU (O-RAN RU). The RU 180 may be replaced with a second network entity for a base station (eg, gNB) in embodiments of the present disclosure, if necessary.

Although a base station is described as including a DU and an RU in FIG. 1B, various embodiments of the present disclosure are not limited thereto. In some embodiments, the base station is configured to perform a function of a centralized unit (CU) configured to perform a function of upper layers (eg, packet data convergence protocol (PDCP), RRC) of an access network and a lower layer It can be implemented as a distributed deployment according to a distributed unit (DU). In this case, a distributed unit (DU) may include a digital unit (DU) and a radio unit (RU) of FIG. 1 . Between a core (eg, 5G core (5GC) or next generation core (NGC)) network and a radio network (RAN), base stations may be implemented in a structure in which CU, DU, and RU are arranged in order. An interface between a CU and a distributed unit (DU) may be referred to as an F1 interface.

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

2 illustrates a configuration of a digital unit (DU) in a wireless communication system according to various embodiments of the present disclosure. The configuration illustrated in FIG. 2 can be understood as a configuration of the DU 160 in FIG. 1B as part of a base station. Terms such as '... unit' and '... unit' used below refer to a unit that processes at least one function or operation, which may be implemented by hardware or software, or a combination of hardware and software. there is.

Referring to FIG. 2 , the DU 160 includes a communication unit 210, a storage unit 220, and a control unit 230.

The communication unit 210 may perform functions for transmitting and receiving signals in a wired communication environment. The communication unit 210 may include a wired interface for controlling a direct connection between devices through a transmission medium (eg, copper wire or optical fiber). For example, the communication unit 210 may transmit an electrical signal to another device through a copper wire or perform conversion between an electrical signal and an optical signal. The communication unit 210 may be connected to a radio unit (RU). The communication unit 210 may be connected to a core network or to a distributed CU.

The communication unit 210 may perform functions for transmitting and receiving signals in a wireless communication environment. For example, the communication unit 210 may perform a conversion function between a baseband signal and a bit string according to the physical layer standard of the system. For example, during data transmission, the communication unit 210 generates complex symbols by encoding and modulating a transmission bit stream. In addition, upon receiving data, the communication unit 210 restores the received bit stream by demodulating and decoding the baseband signal. Also, the communication unit 210 may include a plurality of transmission/reception paths. Also, according to an embodiment, the communication unit 210 may be connected to a core network or connected to other nodes (eg, integrated access backhaul (IAB)).

The communication unit 210 may transmit and receive signals. To this end, the communication unit 210 may include at least one transceiver. For example, the communication unit 210 may transmit a synchronization signal, a reference signal, system information, a message, a control message, a stream, control information, or data. Also, the communication unit 210 may perform beamforming.

The communication unit 210 transmits and receives signals as described above. Accordingly, all or part of the communication unit 210 may be referred to as a 'transmitting unit', a 'receiving unit' or a 'transceiving unit'. In addition, in the following description, transmission and reception performed through a radio channel are used to mean that the above-described processing is performed by the communication unit 210.

Although not shown in FIG. 2 , the communication unit 210 may further include a backhaul communication unit for connecting to a core network or another base station. The backhaul communication unit provides an interface for communicating with other nodes in the network. That is, the backhaul communication unit converts a bit string transmitted from a base station to another node, for example, another access node, another base station, an upper node, a core network, etc., into a physical signal, and converts a physical signal received from another node into a bit string. convert

The storage unit 220 stores data such as a basic program for operation of the DU 160, an application program, and setting information. The storage unit 220 may include a memory. The storage unit 220 may include volatile memory, non-volatile memory, or a combination of volatile and non-volatile memories. And, the storage unit 220 provides the stored data according to the request of the control unit 230.

The controller 230 controls overall operations of the DU 160. For example, the control unit 230 transmits and receives signals through the communication unit 210 (or through the backhaul communication unit). Also, the control unit 230 writes and reads data in the storage unit 220 . In addition, the control unit 230 may perform functions of a protocol stack required by communication standards. To this end, the controller 230 may include at least one processor.

The configuration of the DU 160 shown in FIG. 2 is only an example, and an example of a DU performing various embodiments of the present disclosure is not limited from the configuration shown in FIG. 2 . According to various embodiments, some configurations may be added, deleted, or changed.

3 illustrates a configuration of a radio unit (RU) in a wireless communication system according to various embodiments of the present disclosure. The configuration illustrated in FIG. 3 may be understood as a configuration of the RU 180 in FIG. 1B as part of a base station. Terms such as '... unit' and '... unit' used below refer to a unit that processes at least one function or operation, which may be implemented by hardware or software, or a combination of hardware and software. there is.

Referring to FIG. 3 , the RU 180 includes a communication unit 310, a storage unit 320, and a control unit 330.

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

Also, the communication unit 310 may include a plurality of transmission/reception paths. Furthermore, the communication unit 310 may include an antenna unit. The communication unit 310 may include at least one antenna array composed of a plurality of antenna elements. In terms of hardware, the communication unit 310 may include a digital circuit and an analog circuit (eg, a radio frequency integrated circuit (RFIC)). Here, the digital circuit and the analog circuit may be implemented in one package. Also, the communication unit 310 may include a plurality of RF chains. The communication unit 310 may perform beamforming. The communication unit 310 may apply a beamforming weight to the signal in order to give the signal to be transmitted and received a direction according to the setting of the control unit 330 . According to an embodiment, the communication unit 310 may include a radio frequency (RF) block (or RF unit).

Also, the communication unit 310 may transmit and receive signals. To this end, the communication unit 310 may include at least one transceiver. The communication unit 310 may transmit a downlink signal. The downlink signal includes a synchronization signal (SS), a 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, the communication unit 310 may receive an uplink signal. The uplink signal includes a random access related signal (e.g., random access preamble (RAP) (or Msg1 (message 1)), Msg3 (message 3)), a reference signal (e.g., SRS (sounding reference signal), DM) -RS), or a power headroom report (PHR).

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

The storage unit 320 stores data such as a basic program for operation of the RU 180, an application program, and setting information. The storage unit 320 may include volatile memory, non-volatile memory, or a combination of volatile and non-volatile memories. And, the storage unit 320 provides the stored data according to the request of the control unit 330. According to an embodiment, the storage unit 320 may include a memory for conditions, commands, or setting values related to the SRS transmission method.

The controller 330 controls overall operations of the RU 180. For example, the control unit 330 transmits and receives signals through the communication unit 310 . Also, the control unit 330 writes and reads data in the storage unit 320 . Also, the control unit 330 may perform protocol stack functions required by communication standards. To this end, the controller 330 may include at least one processor. In some embodiments, the controller 330 may configure the SRS to be transmitted to the DU 160 based on an antenna number. Also, in some embodiments, the control unit 330 may be configured to transmit the SRS to the DU 160 after uplink transmission. The control unit 330 is a command set or code stored in the storage unit 320, and the condition command or set value according to the SRS transmission method is a command/code or command/code that is at least temporarily residing in the control unit 330. It may be a storage space for storing , or a part of circuitry constituting the control unit 330 . Also, the controller 330 may include various modules for performing communication. According to various embodiments, the control unit 330 may control the RU 180 to perform operations according to various embodiments described below.

4 shows an example of function splitting. As wireless communication technology develops (e.g., 5G ( ^5th generation) communication system (or introduction of NR (new radio) communication system), the frequency band used increases more and more, and the cell radius of the base station becomes very small), The number of RUs required to be installed further increased In addition, in the 5G communication system, the amount of transmitted data increased by more than 10 times, and the transmission capacity of the wired network transmitted through the fronthaul greatly increased. Therefore, in order to reduce the transmission capacity of the wired network and the installation cost of the wired network, some functions of the modem of the DU may be significantly increased in the 5G communication system. Technologies have been proposed to lower the transmission capacity of the fronthaul by transferring to , and these technologies may be referred to as 'function split'. The present disclosure has been described with respect to a 5G communication system, but is not limited thereto, and 6G (6 ^th generation) can be equally or similarly applied to communication systems.

In order to reduce the burden of the DU, a method of extending the role of the RU responsible for only the RF function to some functions of the physical layer is considered. In this case, as the RU performs functions of a higher layer, the throughput of the RU increases, so the transmission bandwidth in the fronthaul increases, and at the same time, delay time requirement constraints due to response processing may be lowered. On the other hand, as the RU performs higher layer functions, the virtualization gain decreases and the size/weight/cost of the RU increases. Considering the trade-off of the advantages and disadvantages described above, it is desired to implement an optimal functional separation.

Referring to FIG. 4 , functional separations in the physical layer below the MAC layer are shown. In the case of downlink (DL) transmitting a signal to a terminal through a wireless network, the base station sequentially performs channel encoding/scrambling, modulation, layer mapping, antenna mapping, RE mapping, digital beamforming (eg, precoding), IFFT conversion/CP insertion, and RF conversion can be performed. In the case of uplink (UL) receiving 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 decoder. Mapping, channel estimation, layer demapping, demodulation, and decoding/desscrambling can be performed. Separation of uplink functions and downlink functions may be defined in various types according to the need between vendors, discussions on standards, and the like according to the above-described trade-off.

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

According to an embodiment, when large-capacity signal processing is expected, such as in the FR1 MMU, function separation in a relatively high layer (eg, the fourth function separation 420b) may be required to reduce fronthaul capacity. In addition, since functional separation (eg, the sixth functional separation 430) in a too high layer can cause a burden on the implementation of the RU due to the complexity of the control interface and the inclusion of a large number of PHY processing blocks in the RU, the DU Appropriate separation of functions may be required according to the arrangement and implementation method of the RU and the RU.

According to an embodiment, when precoding of data received from the DU cannot be processed (ie, when there is a limit to the precoding capability of the RU), the third function separation 420a or lower function Separation (eg, second functional separation 410 ) may be applied. Conversely, if it has the ability to process precoding of data received from the DU, the fourth functional separation 420b or higher functional separation (eg, the sixth functional separation 430) may be applied. Hereinafter, embodiments in the present disclosure are described based on the third functional separation 420a (category A) or the fourth functional separation 420b (category B) for performing the beamforming process in the RU unless otherwise limited. However, configuration of an embodiment through different functional separations is not excluded. The functional configuration, signaling, or operation of FIGS. 5A to 13 described below may be applied not only to the third functional separation 420a or the fourth functional separation 420b but also to other functional separations.

In the embodiments of the present disclosure, when transmitting a message between a DU (eg, DU 160 of FIG. 1B) and an RU (eg, RU 180 of FIG. 1B), eCPRI and O-RAN standards are exemplified as fronthaul interfaces. is described negatively. An eCPRI header, an O-RAN header, and additional fields may be included in the Ethernet payload of the message. Hereinafter, various embodiments of the present disclosure are described using standard terms of eCPRI or O-RAN, but other expressions having equivalent meanings to each term may be substituted for various embodiments of the present disclosure.

As the fronthaul transport protocol, Ethernet and eCPRI, which are easy to share with the network, can be used. An eCPRI header and an O-RAN header may be included in the Ethernet payload. The eCPRI header may be positioned in front of the Ethernet payload. The contents of the eCPRI header are as follows.

l ecpriVersion (4 bits): 0001b (fixed value)

l ecpriReserved (3 bits): 0000b (fixed value)

l ecpriConcatenation (1 bit): 0b (fixed value)

l ecpriMessage (1 byte): Message type

l ecpriPayload (2 bytes): Payload size in bytes

l ecpriRtcid / ecpriPcid (2 bytes): x, y, z may be configured through a management plane (M-plane). This field may indicate a transmission path (extended antenna-carrier (eAxC) in eCPRI) of a control message according to various embodiments during multi-layer transmission.

n CU_Port_ID (x bits): Identifies the channel card. Can be distinguished including Modem (2 bits for channel card, 2 bits for Modem)

n BandSector_ID (y bits): Divided according to Cell/Sector

n CC_ID (z bits): classified according to component carrier

n RU_Port_ID (w bits): classified according to layer, T, antenna, etc.

l ecpriSeqid (2 bytes): Sequence ID is managed for each ecpriRtcid/ecpriPcid, and Sequence ID and subsequence ID are separately managed. Radio-transport-level fragmentation is possible using Subsequence ID (different from Application-level fragmentation)

Fronthaul application protocols include a control plane (C-plane), a user plane (U-plane), a synchronization plane (S-plane), and a management plane (M -plane) may be included.

The control plane may be configured to provide scheduling information and beamforming information through a control message. The user plane may include user downlink data (IQ data or SSB/RS), uplink data (IQ data or SRS/RS), or PRACH data. The above-described weight vector of beamforming information may be multiplied by user data. A sync plane can be related to timing and synchronization. The management plane may be related to initial setup, non-realtime reset or reset, and non-realtime report.

To define the type of message transmitted in the control plane, a Section Type is defined. Section Type may indicate the purpose of a control message transmitted in the control plane. For example, the purpose of each section type is as follows.

n sectionType=0: DL idle/guard periods - Used for Tx blanking for power saving

n sectionType=1: Maps BF index or weight (O-RAN mandatory BF method) to RE of DL/UL channel

n sectionType=2: reserved

n sectionType = 3: Mapping beamforming index or weight to PRACH and RE of mixed-numerology channel

n sectionType=4: reserved

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

n sectionType=6: Periodically transmits UE channel information so that RU can calculate real-time BF weight (O-RAN optional BF method)

n sectionType=7: used for LAA support

The eCPRI-based fronthaul interface currently used in O-RAN supports the LTE communication system and the NR communication system. As it becomes possible to support multi-cell with a small number by virtualizing DUs, other communication systems may also be required for a scheme to be supported by DUs. According to embodiments of the present disclosure, an eCPRI-based fronthaul interface may support global system for mobile communications (GSM). Hereinafter, in the present disclosure, GSM is exemplified as another communication system, but the application of other communication schemes (eg, wideband code division multiple access (WCDMA), code division multiple access (CDMA), etc.) is not excluded.

GSM is a second generation communication standard and is a communication method based on timed division multiplexing access (TDMA). CPRI supports GSM. Based on the fronthaul interface of CPRI, a method for applying GSM to eCPRI of O-RAN is described.

5A illustrates a scheduling scenario in an O-RAN based fronthaul interface according to embodiments of the present disclosure.

Referring to FIG. 5A, it is assumed that a downlink control plane (C-plane) message is transmitted (501). The downlink control plane message may be transmitted from the O-DU 510 to the O-RU 520. For example, the downlink control plane message may be a downlink control plane message from slot #M to slot #N. After the downlink control plane message is transmitted, the O-DU 510 may transmit a downlink user plane message to the O-RU 520. For example, the downlink user plane message message may be a downlink user plane message from slot #M to slot #N.

Assume that an uplink control plane (C-plane) message is transmitted (503). An uplink control plane message may be transmitted from the O-DU 510 to the O-RU 520. For example, the uplink control plane message may be an uplink control plane message from slot #M to slot #N. After the uplink control plane message is transmitted, the O-RU 510 may transmit an uplink user plane message to the O-DU 520. For example, the uplink user plane message may be an uplink user plane message from slot #M to slot #N.

5B illustrates an example of a base station structure in an O-RAN based fronthaul interface according to embodiments of the present disclosure.

Referring to FIG. 5B, in an O-RAN-based fronthaul interface, a base station structure includes an O-DU 510 and one or more O-RUs 520-1 to 520-N (eg, O-RU #1, O-RU #2, ??, O-RU #N), and the O-DU 510 and one or more O-RUs 520-1 to 520-N have one or more front holes ( 530-1 to 530-N). That is, the O-DU 510 may be connected through each O-RU and a corresponding front hole.

Hereinafter, a description of each of the one or more O-RUs 520-1 to 520-N may be applied to the description of the O-RU 520. Also, a description of each of the one or more front holes 530 - 1 to 530 -N may be applied to the front hole 530 .

According to an embodiment, the O-RAN-based fronthaul interface may correspond to option 7-2x in the functional separation of FIG. 4 . Specifically, the O-DU 510 may perform a high-PHY function for at least one of NR or LTE, and the O-RU 520 may perform a low-PHY function for at least one of NR or LTE. . The high-PHY function may include scrambling (or descrambling), modulation (or demodulation), layer mapping (or channel estimation), and RE mapping (or RE demapping). The low-PHY functions may include iFFT and CP addition (or FFT and CP removal), DAC (or ADC).

The fronthaul 530 may be a path through which data corresponding to an O-RAN packet is transferred between the O-DU 510 and the O-RU 520.

The O-DU 510 may transmit a downlink (DL) message. Specifically, the O-DU 510 may transmit a downlink (DL) message to the O-RU 520. The downlink message may be a message including a packet corresponding to a downlink control plane (DL C-plane). The downlink message may be a message including a packet corresponding to the uplink control plane (UL C-plane). The downlink message may be a message including a packet corresponding to a downlink user plane (DL user plane, DL U-plane). The downlink message may be a message including a packet corresponding to the synchronization plane. The downlink message may be a message including a packet corresponding to the management plane.

O-RU 520 may transmit an uplink message. Specifically, the O-RU 520 may transmit an uplink message to the O-DU 510. The uplink message may include a packet corresponding to the uplink user plane. An uplink message may include a packet corresponding to a sync plane. The uplink message may be a message including a packet corresponding to the management plane.

In the 5G or 6G band, due to the high-frequency characteristics, the radio wave coverage is short, so more base stations must be installed to overcome the small coverage compared to 4G communication and the straightness of radio waves. The high density of base stations causes an increase in power consumption in cellular networks. Therefore, a plan for power saving is required during base station operation. For energy saving, embodiments of the present disclosure propose an apparatus and method for power saving in a fronthaul between an O-DU and an O-RU of an O-RAN based base station.

Embodiments of the present disclosure propose a power saving apparatus and method for power saving by generating a control signal for turning off the power of a transmitter when radio resources are not allocated. For example, embodiments of the present disclosure propose a power saving apparatus and method for identifying a case in which a radio resource is not allocated based on acquired scheduling information and turning off power. Specifically, in embodiments of the present disclosure, when data corresponding to a downlink control plane packet, data corresponding to an uplink control plane packet, and downlink user plane packet do not all exist, power of a transmitter is turned off. A power saving device and method are proposed. Hereinafter, a power saving method is described through FIGS. 6 to 13 .

6 illustrates examples of protocol structures of messages in an O-RAN based fronthaul interface according to embodiments of the present disclosure. Specifically, FIG. 6 shows a message protocol structure 610 of each of a control plane (C-plane) and a user plane (U-plane) and a protocol structure of a synchronization plane (S-plane) ( 620) is shown.

Referring to FIG. 6, the message protocol structure 610 of each of the control plane and the user plane includes an Ethernet L1 layer, an Ethernet L2 layer + virtual local area network (VLAN), an internet protocol (IP) layer (optional), It may include a user datagram protocol (UDP) layer (optional), and an enhanced common public radio interface (eCPRI)/radio over ethernet (ROE) layer.

The protocol structure 620 of the synchronization plane (S-plane) may include an Ethernet L1 layer, an Ethernet L2 layer, a precision time protocol (PTP) layer, and a synchronous ethernet (SyncE) layer.

In an O-RAN-based fronthaul interface, application protocols include a control plane (C-plane), a user plane (U-plane), a synchronization plane (S-plane), and It may include a management plane (M-plane).

A message related to the control plane may be a message providing scheduling information and beamforming information. For example, a message related to scheduling information may be a message including section ID information, beam ID information, or UE ID information. A message related to the control plane may be transmitted through a message protocol structure 610 of each of the control plane (C-plane) and the user plane (U-plane).

The message related to the user plane may be a message including user downlink data (IQ data or SSB/RS), uplink data (IQ data or SRS/RS), or PRACH data. A message related to the user plane may be transmitted through the message protocol structure 610 of each of the control plane (C-plane) and the user plane (U-plane).

Messages related to sync planes may relate to timing and synchronization. For example, a message related to a synchronization plane may be a message including data transmitted to match synchronization between O-DUs and O-RUs. A message related to the synchronization plane may be transmitted through a protocol structure 620 of a synchronization plane (S-plane).

Messages related to the management plane may be messages related to initial setup, non-realtime reset or reset, and non-realtime report.

7 illustrates an example of a structure of an O-DU (O-RAN DU) in an O-RAN based fronthaul interface according to an embodiment of the present disclosure.

Referring to FIG. 7 , in an O-RAN-based fronthaul interface, a base station may be composed of an O-DU 510 and one or more O-RUs 520-1 to 520-N, and an O-DU ( 510) and one or more O-RUs 520-1 to 520-N may be connected through one or more front holes 530-1 to 530-N. In addition, the O-DU 510 includes a media access control (MAC) scheduler 710, a control plane message generator 720, and a user plane message generator 730, one or more eCPRI/ROEs 740-1 to 740- N), one or more Ethernet L2+VLANs (750-1 to 750 to N), sync plane message 751, management plane message 753, one or more eMACs (ethernet media access controllers) (760-1 to 760 -N), one or more PHY (physical) transmitters 770-1 to 770-N, and one or more optical transmitters 780-1 to 780-N. In addition, the O-DU 510 may include an O-DU power saving engine 790.

Hereinafter, a description of each of the one or more O-RUs 520-1 to 520-N may be applied to the description of the O-RU 520. Also, a description of each of the one or more front holes 530 - 1 to 530 -N may be applied to the front hole 530 . In addition, a description of each of the one or more eCPRI/ROEs 740-1 to 740-N may be applied as a description of the eCPRI/ROE 740. Also, a description of each of the one or more Ethernet L2+VLANs 750-1 to 750~N may be applied to the description of the Ethernet L2+VLAN 750. Also, a description of each of the one or more eMACs 760-1 to 760-N may be applied to the eMAC 760. In addition, a description of each of the one or more PHY transmitters 770-1 to 770-N may be applied as a description of the PHY transmitter 770. Also, a description of each of the one or more optical transmitters 780-1 to 780-N may be applied to the optical transmitter 780.

The control plane message may be generated based on scheduling information obtained from the MAC scheduler 710 . Also, the user plane message may be generated based on scheduling information obtained from the MAC scheduler 710. For example, the downlink control plane message may be generated based on the downlink scheduling information 711 for slot #N obtained from the MAC scheduler 710. In addition, the uplink control plane message may be generated based on the uplink scheduling information 711 for slot #N obtained from the MAC scheduler 710. For another example, the downlink user plane message may be generated based on the downlink control plane message 723 received from the control plane message generator 720 . Hereinafter, 1. transmission of control plane messages, 2. transmission of user plane messages, and 3. transmission of synchronization plane messages and management plane messages are described.

1. Transmission of Control Plane Messages

The control plane message for slot #N may be generated based on downlink or uplink scheduling information 711 for slot #N obtained from the MAC scheduler 710 .

For example, the control plane message generator 720 may generate a downlink control plane message for slot #N based on the downlink scheduling information 711 for slot #N obtained from the MAC scheduler 710. there is. Specifically, the control plane message generator 720 may identify the presence or absence of downlink scheduling information based on the downlink scheduling information 711 for slot #N obtained from the MAC scheduler 710. As the control plane message generator 720 identifies the presence or absence of downlink scheduling information based on the downlink scheduling information 711 for slot #N, the information for slot #N based on the presence or absence of the identified downlink scheduling information. A downlink control plane message may be generated.

For another example, the control plane message generator 720 may generate an uplink control plane message for slot #N based on uplink scheduling information 711 for slot #N obtained from the MAC scheduler 710. can Specifically, the control plane message generator 720 may identify the presence or absence of uplink scheduling information based on the uplink scheduling information 711 for slot #N obtained from the MAC scheduler 710 . As the control plane message generator 720 identifies the presence or absence of uplink scheduling information, it may generate an uplink control plane message for slot #N based on the identified presence or absence of uplink scheduling information.

The control plane message generator 720 may transmit the downlink control plane message for the generated slot #N to the eCPRI/ROE 740 (721). In addition, the control plane message generator 720 may transmit the downlink control plane message for the generated slot #N to the user plane message generator 730 (723). The downlink user plane message for slot #N may be generated based on the downlink control plane message for slot #N transmitted to the user plane message generator 730 . In addition, the control plane message generator 720 may transmit an uplink control plane message for the generated slot #N to the eCPRI/ROE 740 (721).

1) When there is downlink scheduling information

When the control plane message generator 720 identifies that there is downlink scheduling information (based on the downlink scheduling information for slot #N obtained from the MAC scheduler 710, it identifies that there is downlink scheduling information) case). As the control plane message generator 720 identifies that there is downlink scheduling information, the control plane message generator 720 may generate a downlink control plane message for slot #N.

The generated downlink control plane message for slot #N may be transmitted to the O-RU 520 for allocating downlink resources for slot #N. For example, the downlink control plane message for the generated slot #N may be transmitted to the O-RU 520 through the fronthaul 530. Specifically, the downlink control plane message for the generated slot #N is eCPRI/ROE 740, Ethernet L2 + VLAN 750, eMAC 760, PHY transmitter 770, optical transmitter 780, and front It can be transmitted to the O-RU 520 through the hole 530.

Also, the generated downlink control plane message for slot #N may be transmitted to the user plane message generator 730 to generate a downlink user plane message for slot #N (723).

2) When there is uplink scheduling information

When the control plane message generator 720 identifies that there is uplink scheduling information for slot #N (based on the uplink scheduling information for slot #N obtained from the MAC scheduler 710, the uplink scheduling information Suppose that it identifies that there is). If the control plane message generator 720 has uplink scheduling information for slot #N, the control plane message generator 720 may generate an uplink control plane message for slot #N.

The generated uplink control plane message for slot #N may be transmitted to the O-RU 520 in order to allocate uplink resources for slot #N. For example, the uplink control plane message for the generated slot #N may be transmitted to the O-RU 520 through the fronthaul 530. Specifically, the uplink control plane message for the generated slot #N is eCPRI/ROE 740, Ethernet L2 + VLAN 750, eMAC 760, PHY transmitter 770, optical transmitter 780, and front It can be transmitted to the O-RU 520 through the hole 530.

3) When there is no downlink scheduling information

When the control plane message generator 720 identifies that there is no downlink scheduling information for slot #N (based on the downlink scheduling information for slot #N obtained from the MAC scheduler 710, the downlink scheduling information Assume there is no identification). If the control plane message generator 720 does not have downlink scheduling information for slot #N, the control plane message generator 720 does not generate a downlink control plane message for slot #N.

Since the downlink control plane message for slot #N is not generated, the downlink control plane message for slot #N is not transmitted to the O-RU 520 . The downlink control plane message for slot #N is transmitted through eCPRI/ROE 740, Ethernet L2+VLAN 750, eMAC 760, PHY transmitter 770, optical transmitter 780, and fronthaul 530. It is not transmitted to the O-RU 520 through

4) When there is no uplink scheduling information

When the control plane message generator 720 identifies that there is no uplink scheduling information for slot #N (based on the uplink scheduling information for slot #N obtained from the MAC scheduler 710, the uplink scheduling information Assume there is no identification). If the control plane message generator 720 does not have uplink scheduling information for slot #N, the control plane message generator 720 does not generate an uplink control plane message for slot #N.

Since the uplink control plane message for slot #N is not generated, the uplink control plane message for slot #N is not transmitted to the O-RU 520 . Uplink control plane messages for slot #N are sent through eCPRI/ROE 740, Ethernet L2+VLAN 750, eMAC 760, PHY transmitter 770, optical transmitter 780, and fronthaul 530. It is not transmitted to the O-RU 520 through

2. Sending User Plane Messages

1) When there is downlink scheduling information

When the control plane message generator 720 identifies that there is downlink scheduling information (based on the downlink scheduling information for slot #N obtained from the MAC scheduler 710, it identifies that there is downlink scheduling information) case). As control plane message generator 720 identifies that there is downlink scheduling information, user plane message generator 730 can generate a downlink user plane message for slot #N. Specifically, the user plane message generator 730 may generate a downlink user plane message for slot #N based on the received downlink control plane message 723 for slot #N.

The downlink user plane message for the generated slot #N may be transmitted to the O-RU 520. For example, the generated downlink user plane message for slot #N may be transmitted to the O-RU 520 through the fronthaul 530. Specifically, the downlink user plane message for the generated slot #N is eCPRI/ROE 740, Ethernet L2 + VLAN 750, eMAC 760, PHY transmitter 770, optical transmitter 780, and front It can be transmitted to the O-RU 520 through the hole 530.

2) When there is uplink scheduling information

When the control plane message generator 720 identifies that there is uplink scheduling information for slot #N (based on the uplink scheduling information for slot #N obtained from the MAC scheduler 710, the uplink scheduling information Assume that it is identified that there is). As the control plane message generator 720 identifies that there is uplink scheduling information for slot #N, the control plane message generator 720 may generate an uplink control plane message for slot #N.

The O-RU 520 may generate an uplink user plane message for slot #N based on the received uplink control plane message for slot #N. As such, if there is uplink scheduling information, since the O-RU 520, not the O-DU 510, generates and transmits the uplink user plane message for slot #N, the O-DU 510 It is not the subject of creation and transmission of user plane messages.

3) When there is no downlink scheduling information

When the control plane message generator 720 identifies that there is no downlink scheduling information for slot #N (based on the downlink scheduling information for slot #N obtained from the MAC scheduler 710, the downlink scheduling information Assume there is no identification). As control plane message generator 720 identifies that there is no downlink scheduling information for slot #N, control plane message generator 720 does not generate a downlink control plane message for slot #N. Also, the user plane message generator 730 does not generate a downlink user plane message for slot #N. Specifically, since the downlink control plane message for slot #N is not generated by the control plane message generator 720, the generated downlink control plane message for slot #N is transmitted to the user plane message generator 730. It doesn't work. Accordingly, since there is no downlink control plane message for slot #N transmitted, the user plane message generator 730 cannot generate a downlink user plane message for slot #N.

Since the downlink control plane message and downlink user plane message for slot #N are not generated, the downlink control plane message and downlink user plane message for slot #N are not transmitted to the O-RU 520 . Specifically, downlink control plane messages for slot #N are eCPRI/ROE 740, Ethernet L2 + VLAN 750, eMAC 760, PHY transmitter 770, optical transmitter 780, and fronthaul ( 530) is not transmitted to the O-RU 520.

Also, since the downlink user plane message for slot #N is not generated, the downlink user plane message for slot #N is not transmitted to the O-RU 520 . Specifically, downlink user plane messages for slot #N are eCPRI/ROE 740, Ethernet L2 + VLAN 750, eMAC 760, PHY transmitter 770, optical transmitter 780, and fronthaul ( 530) is not transmitted to the O-RU 520.

4) When there is no uplink scheduling information

When the control plane message generator 720 identifies that there is no uplink scheduling information for slot #N (based on the uplink scheduling information for slot #N obtained from the MAC scheduler 710, the uplink scheduling information Assume there is no identification). If there is no uplink scheduling information for slot #N, the control plane message generator 720 does not generate an uplink control plane message for slot #N.

Since the uplink control plane message for slot #N is not generated, the uplink control plane message for slot #N is not transmitted to the O-RU 520 . Specifically, the uplink control plane message for slot #N is eCPRI/ROE 740, Ethernet L2 + VLAN 750, eMAC 760, PHY transmitter 770, optical transmitter 780, and fronthaul ( 530) is not transmitted to the O-RU 520.

3. Transmission of sync plane messages and management plane messages

Sync plane messages are generated by sync plane message generator 751 and management plane messages are generated by management plane message generator 753 . The sync plane message is transmitted to O-RU 520 through Ethernet L2+VLAN 750, eMAC 760, PHY transmitter 770, optical transmitter 780, and fronthaul 530. In addition, the management plane message is transmitted to the O-RU 520 through the Ethernet L2+VLAN 750, the eMAC 760, the PHY transmitter 770, the optical transmitter 780, and the fronthaul 530.

When there is no downlink scheduling information and uplink scheduling information for slot #N, the downlink control plane message, uplink control plane message, and downlink user plane message for slot #N are transmitted to the O-RU 520 It doesn't work. Also, if fronthaul 530 is not used for transmission of sync plane messages and management plane messages, sync plane messages and management plane messages are not sent to O-RU 520 . Even though no messages are transmitted, leaving the PHY transmitter 770 and the optical transmitter 780 powered on may result in wasted power. Therefore, when there is no downlink scheduling information and uplink scheduling information, a power saving method is proposed by generating a control signal to turn off the power of the transmitter. Specifically, when the power saving device 790 identifies that there is no downlink scheduling information and uplink scheduling information and identifies that fronthaul is not used for transmission of sync plane messages and management plane messages, the power of the transmitter We propose a way to save power by generating a control signal that turns off the power.

Although the present disclosure describes a method of power saving by generating a control signal to turn off the power of a transmitter, other methods of power saving are also possible. For example, the power of the transmitter may be cut off. For another example, the current transmitted to the transmitter may be blocked. As another example, power supplied to the transmitter may be reduced. As another example, only some of the transmitters may be powered off. As another example, it is possible to change the route.

In FIG. 8 , types of information input to the power saving device 790 to save power are described.

8 illustrates an example of information input to a power saving device and an output signal in an O-RAN based fronthaul interface according to embodiments of the present disclosure.

Referring to FIG. 8 , the power saving device 790 may obtain scheduling information 791 for slot #N. For example, the power saving device 790 may obtain downlink scheduling information for slot #N from the MAC scheduler 710 . The power saving device 790 may identify the presence or absence of downlink scheduling information based on the acquired downlink scheduling information for slot #N. For another example, the power saving device 790 may obtain uplink scheduling information for slot #N from the MAC scheduler 710 . The power saving device 790 may identify the presence or absence of uplink scheduling information based on the acquired uplink scheduling information for slot #N.

When there is no downlink scheduling information and uplink scheduling information, the power saving device 790 executes a power saving operation. In the power saving operation, the power saving device 790 generates a control signal to turn off the power of the PHY transmitter 770 and the optical transmitter 780 in order to save power for a section without downlink scheduling information and uplink scheduling information. means to do Although the method of power saving by generating a control signal to turn off the power of the transmitter has been described, it is also possible to save power in other ways. For example, the power of the transmitter may be cut off. For another example, the current transmitted to the transmitter may be blocked. As another example, power supplied to the transmitter may be reduced. As another example, only some of the transmitters may be powered off. As another example, it is possible to change the route.

The power saving device 790 may obtain the delay parameter 820 . The delay parameter 820 may include a control plane delay parameter and a user plane delay parameter. Also, the delay parameter of the control plane may include a delay parameter of the control plane for downlink. Also, the delay parameters of the control plane may include delay parameters of the control plane for uplink. Also, the user plane delay parameter may include a user plane delay parameter for downlink.

The downlink control plane message for slot #N has a start point. And, the downlink control plane message for slot #N has an end point. The time between the start of the downlink control plane message for slot #N and the end of the downlink control plane message for slot #N may be referred to as a transmission window for the downlink control plane message for slot #N.

In addition, the uplink control plane message for slot #N has a start point. And, the uplink control plane message for slot #N has an end point. The time between the start of the uplink control plane message for slot #N and the end of the uplink control plane message for slot #N can be referred to as the transmission window for the uplink control plane message for slot #N.

In addition, the downlink user plane message for slot #N has a start point. And, the downlink user plane message for slot #N has an end point. The time between the start of the downlink user plane message for slot #N and the end of the downlink user plane message for slot #N may be referred to as a transmission window for the downlink user plane message for slot #N.

The delay parameter 820 may include a delay parameter corresponding to the start time of the downlink control plane message for slot #N. Also, the delay parameter 820 may include a delay parameter corresponding to an end point of the downlink control plane message for slot #N. A transmission window of a downlink control plane message for slot #N may be obtained based on a delay parameter corresponding to a start time and a delay parameter corresponding to an end time of the downlink control plane message for slot #N.

Also, the delay parameter 820 may include a delay parameter corresponding to the start time of the uplink control plane message for slot #N. Also, the delay parameter 820 may include a delay parameter corresponding to an end time of an uplink control plane message for slot #N. A transmission window of an uplink control plane message for slot #N may be obtained based on a delay parameter corresponding to a start time and a delay parameter corresponding to an end time of the uplink control plane message for slot #N.

In addition, the delay parameter 820 may include a delay parameter corresponding to the start time of the downlink user plane message for slot #N. Also, the delay parameter 820 may include a delay parameter corresponding to an end point of the downlink user plane message for slot #N. A transmission window of a downlink user plane message for slot #N may be obtained based on a delay parameter corresponding to a start time and a delay parameter corresponding to an end time of the downlink user plane message for slot #N.

The power saving device 790 may obtain indication information 830 about whether the fronthaul 530 is used for transmission of sync plane or management plane messages. Specifically, the power saving device 790 may identify whether the front haul 530 is used for transmission of a sync plane message based on the indication information 830 . In addition, the power saving device 790 may identify whether the fronthaul 530 is used for transmission of the management plane message, based on the indication information 830 . For example, it is assumed that the power saving device 790 identifies that the fronthaul 530 is used for transmission of a sync plane message based on the indication information 830 of the fronthaul 530 . If the power saving device 790 identifies that the fronthaul 530 is used for transmission of the sync plane message based on the indication information 830, the power saving device 790 may use the PHY transmitter 770 and the optical transmitter ( 780) does not generate a control signal to power off. This is because when fronthaul 530 is used for transmission of sync plane messages, power savings for control plane and user plane messages are unnecessary. The power saving device 790 may perform a power saving operation according to embodiments of the present disclosure when the front haul 530 is not used to transmit a sync plane message.

Also, it is assumed that the fronthaul 530 identifies that the power saving device 790 identifies that the fronthaul 530 is used for transmission of management plane messages based on the indication information 830 . If the power saver 790 identifies that the fronthaul 530 is used for transmission of the management plane message based on the indication information 830, the power saver 790 may use the PHY transmitter 770 and the optical transmitter ( 780) does not generate a control signal to power off. This is because when fronthaul 530 is used for transmission of management plane messages, power savings for control plane and user plane messages are unnecessary. The power saving device 790 may execute a power saving operation according to embodiments of the present disclosure when it is not used for a management plane message. That is, the power saving device 790, when the fronthaul 530 is not used for transmission of the sync plane message, in a section in which the downlink control plane message, the uplink control plane message, and the downlink user plane do not exist. A control signal for reducing power may be generated.

That is, when the fronthaul 530 is not used for transmission of any one of the synchronization plane message and the management plane message, the power saving device 790 determines whether the downlink control plane message, the uplink control plane message, and the downlink user A control signal for reducing power in a section where no plane exists may be generated.

For another example, the power saving device 790 determines whether the fronthaul 530 is the sync plane or the management plane based on the information 830 on whether the fronthaul 530 is used for transmission of sync plane or management plane messages. Assume that you have identified that it is not used for transmission of management plane messages. Upon identifying that fronthaul 530 is not being used for transmission of sync plane or management plane messages, power saving device 790 may execute a power saving operation. The power saving device 790 may execute a power saving operation based on the acquired downlink/uplink scheduling information 791 for slot #N. The power saving device 790 may perform a power saving operation when there is no downlink scheduling information and uplink scheduling information. In the power saving operation, the power saving device 790 generates a control signal to turn off the power of the PHY transmitter 770 and the optical transmitter 780 in order to save power for a section without downlink scheduling information and uplink scheduling information. means to do

The power saving device 790 may obtain a normalization time 840 . The normalization time 840 means a time taken from when the power is turned on to normalization when the power is turned on. The normalization time 840 can be used to determine when the PHY transmitter 770 and the optical transmitter 780 are turned on. For example, suppose that the power of the PHY transmitter 770 and the optical transmitter 780 is turned off based on the downlink/uplink scheduling information 791 for slot #N (downlink and uplink for slot #N). If it identifies that there is no uplink scheduling information). When the power is turned off, if it is identified that there is downlink scheduling information for slot #N+1, the PHY transmitter 770 and the optical transmitter 780 transmit a downlink control plane message for slot #N+1. ) should be turned on. When the power is turned off, if it is identified that there is downlink scheduling information for slot #N+1, the PHY transmitter 770 and the optical transmitter 780 transmit information about the downlink user plane message for slot #N+1. ) should be turned on. When the power is turned off, if it is identified that there is uplink scheduling information for slot #N+1, the PHY transmitter 770 and the optical transmitter 780 transmit an uplink control plane message for slot #N+1. ) should be turned on.

Even after the power is turned on, time is required until the PHY transmitter 770 and the optical transmitter 780 are normalized so that they can transmit messages. Specifically, even after the power is turned on, the power of the PHY transmitter 770 and the optical transmitter 780 is turned on ahead of the time it takes for the device to wake up (840) before the earliest time among the messages for slot #N+1. need something

The power saving device 790 may transmit a control signal 850 to turn power on or off. Power saving device 790 is used to save power. For example, the power saving device 790 saves power by generating a control signal to turn off the PHY transmitter 770 and the optical transmitter 780 when the PHY transmitter 770 and the optical transmitter 780 are not in use. used to save Specifically, when the PHY transmitter 770 and the optical transmitter 780 are not used, this means that there is no downlink scheduling information and uplink scheduling information for slot #N, so a downlink control plane message for slot #N, This may mean a time when an uplink control plane message and a downlink user plane message are not transmitted to the O-RU 520 . In addition, the power saving device 790 needs to turn on the power of the PHY transmitter 770 and the optical transmitter 780 when the PHY transmitter 770 and the optical transmitter 780 are used. Specifically, when the PHY transmitter 770 and the optical transmitter 780 are used, it may mean when there is downlink scheduling information and a downlink control plane message is transmitted to the O-RU 520. In addition, when the PHY transmitter 770 and the optical transmitter 780 are used, it may mean that there is downlink scheduling information and a downlink user plane message is transmitted to the O-RU 520. In addition, when the PHY transmitter 770 and the optical transmitter 780 are used, it may mean when there is uplink scheduling information and an uplink control plane message is transmitted to the O-RU 520. 9 to 10, examples of scenarios for power saving are described.

9 illustrates an example of a transmission period of a control plane message and a user plane message in an O-RAN based fronthaul interface according to embodiments of the present disclosure. Referring to FIG. 9, a transmission window 910 of a downlink control plane message for slot #N, a transmission window 920 of an uplink control plane message for slot #N, and a downlink user plane for slot #N It can be seen that the transmission window 930 of the message is shown.

A transmission window of messages for slot #N may be determined based on the acquired delay parameter 820 of the control plane/user plane. For example, the transmission window 910 of the downlink control plane message for slot #N is based on the acquired delay parameter of the downlink control plane, and the start time point 911 of the downlink control plane message for slot #N. ) and the end point 913 of the downlink control plane message for slot #N. For another example, the transmission window 920 of the uplink control plane message for slot #N is based on the obtained delay parameter of the uplink control plane, the start time of the uplink control plane message for slot #N ( 921) and an end point 923 of the uplink control plane message for slot #N. For another example, the transmission window 930 of the downlink user plane message for slot #N is the start time of the downlink user plane message for slot #N based on the obtained delay parameter of the downlink user plane. 931 and an end point 933 of the downlink user plane message for slot #N.

For example, when the power saving device 790 identifies that there is no downlink scheduling information and uplink scheduling information for slot #N based on the downlink/uplink scheduling information 791 for slot #N. Let's assume When it is identified that there is no downlink scheduling information and uplink scheduling information for slot #N, since there is no downlink scheduling information and uplink scheduling information for slot #N, the downlink control plane message and uplink information for slot #N No link control plane message is generated, and no downlink control plane message is generated, so no downlink user plane message is generated. If the downlink control plane message, uplink control plane message, and downlink user plane message are not generated, the downlink control plane message, uplink control plane message, and downlink user plane message are sent to the O-RU 520 Since it is not transmitted to, the PHY transmitter 770 and the optical transmitter 780 are not used. When the PHY transmitter 770 and the optical transmitter 780 are not in use, the power saving device 790 can save power by generating a control signal to turn off the power of the PHY transmitter 770 and the optical transmitter 780. .

If the downlink control plane message, the uplink control plane message, and the downlink user plane message are not all generated, the downlink control plane message, the uplink control plane message, and the downlink user plane message are all sent to the PHY transmitter 770. and not transmitted via the optical transmitter 780. This period can be defined as a period 940 in which there is no message for slot #N. For this period, the power saving device 790 may save power by generating a control signal to turn off the power of the PHY transmitter 770 and the optical transmitter 780 . Hereinafter, the start time 941 and the end time 943 of the interval 940 without a message are described.

1. Start point (941) of the section (940) with no message

Since there is no downlink scheduling information and uplink scheduling information for slot #N, the power saving device 790 generates a control signal to turn off the power of the PHY transmitter 770 and the optical transmitter 780 to save power. Assume a case (when no downlink control plane message, uplink control plane message, and downlink user plane message for slot #N are generated). In order to save power, the power saving device 790 is required to identify the start point 941 of the period 940 in which there is no message for slot #N. This is because it is related to the timing of turning off the power of the PHY transmitter 770 and the optical transmitter 780 for slot #N. Considering that there is scheduling information for slot #N-1, the start point 941 of the period 940 in which there is no message for slot #N is the start point 911 of the downlink control plane message for slot #N. ), the start time 921 of the uplink control plane message for slot #N, and the start time 931 of the downlink user plane message for slot #N. Considering that there is scheduling information for slot #N-1 means that there is downlink scheduling information and uplink scheduling information for slot #N-1, so the downlink control plane message and uplink control for slot #N This means that a case in which either a plane message or a downlink user plane message is generated is considered.

2. End point (943) of the section (940) with no message

Assume that there is downlink scheduling information and uplink scheduling information for slot #N+1, and the power saving device 790 needs to generate a control signal for powering on the PHY transmitter 770 and the optical transmitter 780. Fault (if at least one of the downlink control plane message for slot #N+1, the uplink control plane message, or the downlink user plane message is generated). In order to identify the power-on time, the power saving device 790 is required to identify the end time 943 of the period 940 where there is no message for slot #N. This is because it is related to the power-on timing of the PHY transmitter 770 and the optical transmitter 780 for slot #N+1. Considering that there is scheduling information for slot #N+1, the end point 943 of the no-message period 940 is the end point 913 of the downlink control plane message for slot #N, slot #N The earliest point in time 913 among the end point 923 of the uplink control plane message for slot #N and the end point 933 of the downlink user plane message for slot #N. Considering that there is scheduling information for slot #N+1 means that there is downlink scheduling information and uplink scheduling information for slot #N+1, a downlink control plane message for slot #N+1, and uplink scheduling information for slot #N+1 This means that a case in which either a link control plane message or a downlink user plane message is generated is considered.

A time point at which the power saving device 790 turns off the power of the PHY transmitter 770 and the optical transmitter 780 for slot #N may correspond to the start time point 941 of the message-free period 940 . However, the time at which the power saving device 790 turns on the power of the PHY transmitter 770 and the optical transmitter 780 for slot #N+1 is determined only by the end time 943 of the period 940 without a message. Can't. After turning on the power of the PHY transmitter 770 and the optical transmitter 780 for slot #N+1, during the time until the PHY transmitter 770 and the optical transmitter 780 stabilize to transmit messages, the PHY This is because transmitter 770 and optical transmitter 780 may not operate properly.

Referring to FIG. 10 below, based on the period in which there is no message in the power saving device 790 and the time until the PHY transmitter 770 and the optical transmitter 780 are stabilized to transmit messages, slot #N+1 The time to turn off and turn on the power of the PHY transmitter 770 and the optical transmitter 780 is described.

10 illustrates an example of a power saving period in an O-RAN based fronthaul interface according to embodiments of the present disclosure.

For example, assume that there is no downlink scheduling information and uplink scheduling information for slot #N (1001) and that there is downlink scheduling information and uplink scheduling information for slot #N+1 (1009). . At this time, the power saving period 1007 of the PHY transmitter 770 and the optical transmitter 780 for slot #N is described. Specifically, when the PHY transmitter 770 and optical transmitter 780 for slot #N are turned off (1003) and when the PHY transmitter 770 and optical transmitter 780 for slot #N are turned on ( 1005) is described.

1. Transmission window of messages for slot #N

A transmission window of messages for slot #N may be determined based on the acquired delay parameter 820 of the control plane/user plane. The transmission window 910 of the downlink control plane message for slot #N is the start time point 911 of the downlink control plane message for slot #N and the end time point 913 for the downlink control plane message for slot #N. It consists of The transmission window 920 of the uplink control plane message for slot #N is the start time point 921 of the uplink control plane message for slot #N and the end time point 923 for the uplink control plane message for slot #N. It consists of The transmission window 930 of the downlink user plane message for slot #N is the start time point 931 of the downlink user plane message for slot #N and the end time point 933 for the downlink user plane message for slot #N. It consists of

2. Transmission window of messages for slot #N+1

A transmission window of messages for slot #N+1 may be determined based on the acquired delay parameter 820 of the control plane/user plane. The transmission window 1010 of the downlink control plane message for slot #N+1 is the start time of the downlink control plane message for slot #N+1 and the end time of the downlink control plane message for slot #N+1. It consists of The transmission window 1020 of the uplink control plane message for slot #N+1 is the start time of the uplink control plane message for slot #N+1 and the end time of the uplink control plane message for slot #N+1. It consists of The transmission window 1030 of the downlink user plane message for slot #N+1 is the start time of the downlink user plane message for slot #N+1 and the end time of the downlink user plane message for slot #N+1. It consists of

3. When to turn off the power of the PHY transmitter 770 and the optical transmitter 780 (1003)

Since there is no downlink scheduling information and uplink scheduling information for slot #N, the power saving device 790 generates a control signal to turn off the power of the PHY transmitter 770 and the optical transmitter 780 to save power. Assume a case (when no downlink control plane message, uplink control plane message, and downlink user plane message for slot #N are generated). In order to save power, it is required to identify when to turn off the power of the PHY transmitter 770 and the optical transmitter 780 for slot #N (1003). This is related to the start point 941 of the interval 940 in which there is no message for slot #N. Specifically, the power-off time 1003 is the start time 911 of the downlink control plane message for slot #N, corresponding to the start time 941 of the period 940 in which there is no message for slot #N. , the start time 921 of the uplink control plane message for slot #N, and the start time 931 of the downlink user plane message for slot #N.

4. When to turn on the power of the PHY transmitter 770 and the optical transmitter 780 (1005)

Assume that there is downlink scheduling information and uplink scheduling information for slot #N+1, and the power saving device 790 needs to generate a control signal for powering on the PHY transmitter 770 and the optical transmitter 780. Fault (if at least one of the downlink control plane message for slot #N+1, the uplink control plane message, or the downlink user plane message is generated). To identify the power-on time, it is required to identify the power-on time 1005 of the PHY transmitter 770 and optical transmitter 780 for slot #N. This is related to the end point 943 of the interval 940 in which there is no message for slot #N. In addition, after turning on the power of the PHY transmitter 770 and the optical transmitter 780 for slot #N + 1, the time until the PHY transmitter 770 and the optical transmitter 780 stabilize to transmit messages ( 1040). Time 1040 after PHY transmitter 770 and optical transmitter 780 for slot #N+1 turn on, until PHY transmitter 770 and optical transmitter 780 stabilize to transmit messages may be based on the time 840 it takes for the device to wake up. The PHY transmitter 770 and the optical transmitter 780 transmit a message at the end point 943 of the period 940 in which there is no message for slot #N at the time point 1005 when the power of the optical transmitter 780 is turned on. It may be a value (1041) obtained by subtracting the time (1040) until stabilization so as to be stable. After turning on the power of the PHY transmitter 770 and the optical transmitter 780 for slot #N+1, for a time period until the PHY transmitter 770 and the optical transmitter 780 stabilize to transmit messages (1040 ), the PHY transmitter 770 and the optical transmitter 780 may not operate properly.

11 is a flowchart for power saving in a power saving device in an O-RAN based fronthaul interface according to an embodiment of the present disclosure.

In operation 1110, the power saving device 790 monitors scheduling information for the slot. For example, the power saving device 790 may obtain downlink/uplink scheduling information 791 for a slot. When there is scheduling information (1111), the power saving device 790 maintains the power-on state (1180) of the PHY transmitter 770 and the optical transmitter 780. If there is no scheduling information (1113), the power saving device 790 should check whether the fronthaul 530 is used for transmission of a sync plane or management plane message.

At operation 1120, power saving device 790 checks whether fronthaul 530 is used for transmission of sync plane or management plane messages. For example, based on the information 830 whether the fronthaul 530 is used for transmission of sync plane or management plane messages, the power saving device 790 determines whether the fronthaul 530 is the sync plane or the management plane. It can identify whether it is used for transmission of messages. If the power saver 790 identifies 1121 that the fronthaul 530 is used for transmission of sync plane or management plane messages, the power saver 790 transmits power to the PHY transmitter 770 and the optical transmitter 780. Maintain the power-on state (1180). If the power saver 790 identifies 1123 that the fronthaul 530 is not used for transmission of sync plane or management plane messages, the power saver 790 calculates a period without messages.

In operation 1130, the power saving device 790 calculates a period without messages. For example, the interval without a message is calculated based on the start time of the interval without a message and the end point of the interval without a message. The start time of the message-free interval should be the latest of the start time of the downlink control plane message, the start time of the uplink control plane message, and the start time of the downlink user plane message. In addition, the end time of the interval without messages should be the earliest among the end time of the downlink control plane message, the end time of the uplink control plane message, and the end time of the downlink user plane message.

In operation 1140, the power saving device 790 determines whether a time point obtained by subtracting the time required for the device to wake up 840 from the end point of the no-message section is later than the start time point of the no-message section. This is because power can be saved for a section based on a time point obtained by subtracting the time required for the device to wake up (840) from the start point of the no-message section to the end point of the no-message section. If the time at which the device wakes up (840) is subtracted from the end of the no-message section (1141) before the start of the no-message section (1141), the power saving device 790 connects the PHY transmitter 770 and the optical transmitter 780 remains turned on (1180). If the time point after subtracting the time it takes for the device to wake up (840) from the end of the no-message section is later than the start of the no-message section (1143), the power saving device 790 determines the current time of the no-message section. Identifies whether it is a starting point or not.

In operation 1150, the power saving device 790 identifies whether the current time is the start of the no-message interval. If the current time is not the start point of the no-message section (1151), the power saving device 790 maintains the PHY transmitter 770 and the optical transmitter 780 in a powered-on state (1180). When the current time is the start time of the no-message section (1153), the power saving device 790 sends a power-off control signal for the PHY transmitter 770 and the optical transmitter 780 in a power-off state (1160). generate

In operation 1170, the power saving device 790 identifies whether the current time is the end of the no-message interval minus the time it takes the device to wake up 840. If the current time is the time it takes for the device to wake up (840) at the end of the message-free interval (1171) at the end of the no-message interval, the power saving device (790) operates on the PHY transmitter (770) and the optical transmitter (780). For the power-on state (1180), a power-on control signal is generated. If the current time is not the time it takes for the device to wake up (840) at the end of the message-less section (1173), the power-off state (1160) is maintained.

12 is a flowchart for power saving in a power saving device of a DU in an O-RAN based fronthaul interface according to an embodiment of the present disclosure.

In operation 1210, the power saving device 790 of the DU may identify whether there is no downlink scheduling information and uplink scheduling information. For example, it is assumed that the power saving device 790 of the DU acquires downlink scheduling information and uplink scheduling information 791 for slot #N. The power saving device 790 of the DU may identify whether there is no downlink scheduling information and uplink scheduling information based on the obtained downlink scheduling information and uplink scheduling information 791 for slot #N.

In operation 1230, the power saving device 790 of the DU identifies a period in which there are no downlink control plane messages, uplink control plane messages, and downlink user plane messages. For example, it is assumed that a period 940 without a downlink control plane message for slot #N, an uplink control plane message for slot #N, and a downlink user plane message for slot #N is identified. The start time of the period 940 with no control plane message for slot #N is the start time 911 of the downlink control plane message for slot #N and the start time of the uplink control plane message for slot #N ( 921), and the start time point 931 of the downlink user plane message for slot #N, which is the latest time point 921. In addition, the end time 943 of the period 940 with no message for slot #N is the end time 913 of the downlink control plane message for slot #N and the uplink control plane message for slot #N. This is the earliest time 913 among the end time 923 and the end time 933 of the downlink user plane message for slot #N.

In operation 1250, the power saving device 790 of the DU generates a control signal for powering off the transmitter of the DU in a period without a downlink control plane message, an uplink control plane message, and a downlink user plane message. do. For example, the PHY transmitter of the DU in a period 940 without a downlink control plane message for slot #N, an uplink control plane message for slot #N, and a downlink user plane message for slot #N ( 770) and the optical transmitter 780 may be assumed to generate a control signal for powering off.

13 is a flowchart for power saving in a power saving device of an RU in an O-RAN based fronthaul interface according to an embodiment of the present disclosure.

In operation 1310, the power saving device of the RU may identify whether there is no uplink scheduling information. For example, the power saving device of the RU may obtain uplink scheduling information based on the uplink control plane message received from the DU. For example, the power saving device of the RU may obtain uplink scheduling information for slot #N based on an uplink control plane message received from the DU for slot #N. Based on the scheduling information acquisition, the power saving device of the RU may identify whether there is no uplink scheduling information based on the acquired uplink scheduling information for slot #N for slot #N.

In operation 1330, the power saving device of the RU identifies a period in which there is no uplink user plane message. For example, it is assumed that a section in which there is no uplink user plane message for slot #N is identified. A period in which there is no uplink user plane message for slot #N is equal to a transmission window for uplink user plane messages for slot #N.

In operation 1350, the power saving device of the RU generates a control signal for powering off the transmitter in a period in which there is no uplink user plane message. For example, it may be assumed that a control signal for turning off power of a PHY transmitter and an optical transmitter of the RU is generated within a period in which there is no uplink user plane message for slot #N.

According to embodiments of the present disclosure, a method performed by a distributed unit (DU) in a wireless communication system includes a process of identifying whether there is no downlink scheduling information and uplink scheduling information for a designated slot, and in the designated slot , when there is no downlink scheduling information and uplink scheduling information, a downlink control plane (C-plane) message, an uplink control plane message, and a downlink user plane (U-plane) It may include identifying a section without a message and generating a control signal for turning off the power of the transmitter of the DU within the section.

According to an embodiment, the start time of the interval is the start time of the interval without the downlink control plane message, the start time of the interval without the uplink control plane message, and the start of the interval without the downlink user plane message. It may correspond to the latest time point among time points.

According to an embodiment, the end time of the interval is the end time of the interval without the downlink control plane message, the end point of the interval without the uplink control plane message, and the end of the interval without the downlink user plane message. It may be determined based on the earliest time point among the time points.

According to an embodiment, the end point of the interval may be determined based on a time from when the power of the transmitter of the DU is turned on until the transmitter of the DU is stabilized to transmit a message.

According to an embodiment, a process of obtaining information on whether a fronthaul between the DU and a radio unit (RU) is used for transmission of a synchronization plane message and whether the fronthaul is used for transmission of a management plane message; and , When the fronthaul is not used for transmission of the synchronization plane message and the fronthaul is not used for transmission of the management plane message, generating a control signal for turning off the power of the transmitter of the DU within the interval can include

According to an embodiment, the transmitter of the DU may include a physical (PHY) transmitter and an optical transmitter.

According to embodiments of the present disclosure, a method performed by a radio unit (RU) includes a process of identifying whether or not there is uplink scheduling information for a designated slot, and when there is no uplink scheduling information for the designated slot , identifying a section in which there is no uplink user plane (U-plane) message, and generating a control signal for powering off the transmitter of the RU within the section.

According to an embodiment, the start time of the section corresponds to the start time of the section without the uplink user plane message, and the end time of the section is determined based on the end time of the section without the uplink user plane message. can

According to an embodiment, the end point of the interval may be determined based on a time from when the power of the transmitter of the RU is turned on until the transmitter of the RU stabilizes to transmit a message.

According to an embodiment, a process of obtaining information about whether a fronthaul between a distributed unit (DU) and the RU is used for transmission of a synchronization plane message and whether the fronthaul is used for transmission of a management plane message; and , When the fronthaul is not used for transmission of the synchronization plane message and the fronthaul is not used for transmission of the management plane message, generating a control signal for turning off the power of the transmitter of the RU within the interval can include

According to an embodiment, the transmitter of the RU may include a physical (PHY) transmitter and an optical transmitter.

According to embodiments of the present disclosure, an apparatus of a distributed unit (DU) in a wireless communication system includes a transmitter and at least one processor coupled to the transmitter, and the at least one processor comprises a downlink for a designated slot. It identifies whether there is no link scheduling information and uplink scheduling information, and if there is no downlink scheduling information and uplink scheduling information for the designated slot, a downlink control plane (C-plane) message, uplink It may be configured to identify a section without a link control plane message and a downlink user plane (U-plane) message, and generate a control signal for powering off the transmitter of the DU within the section.

According to an embodiment, the start time of the interval is the start time of the interval without the downlink control plane message, the start time of the interval without the uplink control plane message, and the start of the interval without the downlink user plane message. It may correspond to the latest time point among time points.

According to an embodiment, the end time of the interval is the end time of the interval without the downlink control plane message, the end point of the interval without the uplink control plane message, and the end of the interval without the downlink user plane message. It may be determined based on the earliest time point among the time points.

According to an embodiment, the end point of the interval may be determined based on a time from when the power of the transmitter of the DU is turned on until the transmitter of the DU is stabilized to transmit a message.

According to an embodiment, the at least one processor determines whether a fronthaul between the DU and a radio unit (RU) is used for transmission of a sync plane message and whether the fronthaul is used for transmission of a management plane message. Control signal for obtaining information and turning off the power of the transmitter of the DU in the interval when the fronthaul is not used for transmission of the sync plane message and the fronthaul is not used for transmission of the management plane message It can be configured to generate.

According to an embodiment, the transmitter of the DU may include a physical (PHY) transmitter and an optical transmitter.

According to embodiments of the present disclosure, an apparatus of a radio unit (RU) in a wireless communication system includes a transmitter and at least one processor coupled to the transmitter, and the at least one processor includes an uplink for a designated slot. Identify whether there is no link scheduling information, identify a section in which there is no uplink user plane (U-plane) message when there is no uplink scheduling information for the designated slot, and within the section, the RU It can be configured to generate a control signal to power off the transmitter of the.

According to an embodiment, the start time of the section corresponds to the start time of the section without the uplink user plane message, and the end time of the section is determined based on the end time of the section without the uplink user plane message. can

According to an embodiment, the end point of the interval may be determined based on a time from when the power of the transmitter of the RU is turned on until the transmitter of the RU stabilizes to transmit a message.

According to an embodiment, the at least one processor determines whether a fronthaul between a distributed unit (DU) and the RU is used for transmission of sync plane messages and whether the fronthaul is used for transmission of management plane messages. Control for obtaining information about the RU and turning off the power of the transmitter of the RU within the interval when the fronthaul is not used for transmission of the sync plane message and the fronthaul is not used for transmission of the management plane message It may be configured to generate a signal.

According to an embodiment, the transmitter of the RU may include a physical (PHY) transmitter and an optical transmitter.

Methods according to the 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 in software, a computer readable storage medium storing one or more programs (software modules) may be provided. One or more programs stored in a computer-readable storage medium are configured for execution by one or more processors in an electronic device. The 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.

Such 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 It can be stored on optical storage devices, magnetic cassettes. Alternatively, it may be stored in a memory composed of a combination of some or all of these. In addition, each configuration memory may be included in multiple numbers.

In addition, the program is provided 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 communication network consisting of a combination thereof. It can be stored on an attachable storage device that can be accessed. Such a storage device may be connected to a device performing an embodiment of the present disclosure through an external port. In addition, a separate storage device on a communication network may be connected to a device performing an embodiment of the present disclosure.

In the specific embodiments of the present disclosure described above, components included in the disclosure are expressed in singular or plural numbers according to the specific embodiments presented. However, the singular or plural expressions are selected appropriately for 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 are composed of the singular number or singular. Even the expressed components may be composed of a plurality.

Meanwhile, in the detailed description of the present disclosure, specific embodiments have been described, but various modifications are possible without departing from the scope of the present disclosure. Therefore, the scope of the present disclosure should not be limited to the described embodiments and should not be defined by the scope of the claims described below as well as those equivalent to the scope of these claims.

Claims (20)

In a method performed by a distributed unit (DU) in a wireless communication system,
Identifying whether there is no downlink scheduling information and uplink scheduling information for a designated slot;
When there is no downlink scheduling information and uplink scheduling information for the designated slot, a downlink control plane (C-plane) message, an uplink control plane message, and a downlink user plane (user plane, U-plane) process of identifying a section without a message;
and generating a control signal for powering off a transmitter of the DU within the interval.
The method according to claim 1, wherein the start time of the interval is the start time of the interval without the downlink control plane message, the start time of the interval without the uplink control plane message, and the start time of the interval without the downlink user plane message How to respond at the latest point in time.
The method according to claim 1, wherein the end time of the period is the end time of the period without the downlink control plane message, the end time of the period without the uplink control plane message, and the end time of the period without the downlink user plane message method determined based on the earliest point in time.
The method of claim 3, wherein the end time of the interval is determined based on a time from when the transmitter of the DU is powered on until the transmitter of the DU is stabilized to transmit a message.
The method according to claim 1, further comprising the steps of: obtaining information on whether a fronthaul between the DU and a radio unit (RU) is used for transmission of a synchronization plane message and whether the fronthaul is used for transmission of a management plane message;
When the fronthaul is not used for transmission of the synchronization plane message and the fronthaul is not used for transmission of the management plane message, generating a control signal to power off the transmitter of the DU within the interval How to include.
The method of claim 1, wherein the transmitter of the DU includes a physical (PHY) transmitter and an optical transmitter.
In a method performed by a radio unit (RU) in a wireless communication system,
identifying whether or not there is uplink scheduling information for a designated slot;
Identifying a section in which there is no uplink user plane (U-plane) message for the designated slot when there is no uplink scheduling information;
And generating a control signal for powering off the transmitter of the RU within the period.
The method according to claim 7, wherein the starting time of the interval corresponds to the starting time of the interval without the uplink user plane message,
The end time of the interval is determined based on the end time of the interval without the uplink user plane message.
The method of claim 8, wherein the end time of the interval is determined based on a time from when the power of the transmitter of the RU is turned on until the transmitter of the RU stabilizes to transmit a message.
The method according to claim 7, further comprising the steps of: obtaining information on whether a fronthaul between a distributed unit (DU) and the RU is used for transmission of a synchronization plane message and whether the fronthaul is used for transmission of a management plane message;
When the fronthaul is not used for transmission of the synchronization plane message and the fronthaul is not used for transmission of the management plane message, generating a control signal for powering off the transmitter of the RU within the interval How to include.
In the apparatus of a distributed unit (DU) in a wireless communication system,
transmitter and
at least one processor coupled with the transmitter;
The at least one processor,
Identifying whether there is no downlink scheduling information and uplink scheduling information for a designated slot;
When there is no downlink scheduling information and uplink scheduling information for the designated slot, a downlink control plane (C-plane) message, an uplink control plane message, and a downlink user plane (user plane, U-plane) identify a section without messages,
An apparatus configured to generate a control signal for powering off a transmitter of the DU within the interval.
The method according to claim 11, wherein the start time of the interval is the start time of the interval without the downlink control plane message, the start time of the interval without the uplink control plane message, and the start time of the interval without the downlink user plane message The device corresponding to the latest point in time.
The method according to claim 11, wherein the end time of the period is the end time of the period without the downlink control plane message, the end time of the period without the uplink control plane message, and the end time of the period without the downlink user plane message device determined based on the earliest point in time.
The apparatus of claim 13, wherein the end point of the interval is determined based on a time from when the transmitter of the DU is powered on until the transmitter of the DU is stabilized to transmit a message.
The method according to claim 11, wherein the at least one processor,
Obtaining information on whether a fronthaul between the DU and a radio unit (RU) is used for transmission of a sync plane message and whether the fronthaul is used for transmission of a management plane message;
When the fronthaul is not used for transmission of the sync plane message and the fronthaul is not used for transmission of the management plane message, a control signal for powering off the transmitter of the DU within the interval is configured to generate Device.
The apparatus of claim 11 , wherein the transmitter of the DU includes a physical (PHY) transmitter and an optical transmitter.
In the device of a radio unit (RU) in a wireless communication system,
transmitter and
at least one processor coupled with the transmitter;
The at least one processor,
Identify whether there is no uplink scheduling information for a designated slot,
For the designated slot, when there is no uplink scheduling information, identifying a section without an uplink user plane (U-plane) message;
Device configured to generate a control signal for powering off the transmitter of the RU within the period.
The method according to claim 17, wherein the starting time of the interval corresponds to the starting time of the interval without the uplink user plane message,
The end time of the section is determined based on the end time of the section without the uplink user plane message.
The apparatus of claim 18, wherein the end point of the interval is determined based on a time from when the power of the transmitter of the RU is turned on until the transmitter of the RU stabilizes to transmit a message.
The method according to claim 17, wherein the at least one processor,
Obtaining information on whether a fronthaul between a distributed unit (DU) and the RU is used for transmission of sync plane messages and whether the fronthaul is used for transmission of management plane messages;
When the fronthaul is not used for transmission of the sync plane message and the fronthaul is not used for transmission of the management plane message, a control signal for powering off the transmitter of the RU within the interval is configured to generate Device.

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