KR20210077621A - Method and apparatus for transmitting and receiving data in fronthaul - Google Patents

Abstract

A method for transmitting and receiving data in a fronthaul and a device thereof are disclosed. An operating method of a first communication node comprises the following steps of: sending a first control plane message including first resource allocation information of first type data to a second communication node; transmitting a first user plane message including the first type data to the second communication node in resources indicated by the first resource allocation information; and transmitting a second control plane message including second resource allocation information of second type data and a preemption indicator indicating that the second type data is transmitted using preempted resources to the second communication node when the second type data is generated.

Description

Method and apparatus for transmitting and receiving data in fronthaul {METHOD AND APPARATUS FOR TRANSMITTING AND RECEIVING DATA IN FRONTHAUL}

The present invention relates to a technology for transmitting and receiving data in a communication system, and more particularly, to a technology for transmitting and receiving URLLC (Ultra-Reliable and Low Latency Communication) data in a fronthaul.

With the development of information and communication technology, various wireless communication technologies are being developed. Representative wireless communication technologies include long term evolution (LTE) and new radio (NR) defined in 3rd generation partnership project (3GPP) standards. LTE may be one of 4G (4th Generation) wireless communication technologies, and NR may be one of 5G (5th Generation) wireless communication technologies.

4G communication system as well as a frequency band of a 4G communication system (eg, a frequency band of 6 GHz or less) for processing of wireless data that increases rapidly after commercialization of a 4G communication system (eg, a communication system supporting LTE) A 5G communication system (eg, a communication system supporting NR) using a frequency band higher than the frequency band of (eg, a frequency band of 6 GHz or more) is being considered. The 5G communication system may support enhanced Mobile BroadBand (eMBB), Ultra-Reliable and Low Latency Communication (URLLC), and Massive Machine Type Communication (mMTC).

On the other hand, the O-RAN (open-radio access network) alliance (alliance) defines a fronthaul (fronthaul) interface. The fronthaul interface may be an interface between an O-RAN distributed unit (O-DU) constituting a base station (eg, eNB, gNB) and an O-RAN radio unit (O-RU). The O-DU may be referred to as a lower layer split-central unit (LLS-CU), and the O-RU may be referred to as a lower layer split-distributed unit (LLS-DU). LLS-CU and LLS-DU may be terms used in 3rd generation partnership project (3GPP).

A preemption operation may be performed for transmission of URLLC data in the fronthaul. For example, the O-DU may transmit a first control plane message including resource allocation information for eMBB data to the O-RU. After that, when transmission of URLLC data is required, the O-DU may reconfigure a resource for URLLC data among resources allocated for eMBB data, and reset resource allocation information (eg, a preempted resource). indicating information) may be transmitted to the O-RU. Different control plane messages (eg, a first control plane message and a second control plane message) are received at the O-RU, but some resources associated with the different control plane messages may be the same. In this case, the O-RU may regard the second control plane message as an error message. Therefore, URLLC transmission may not be performed.

An object of the present invention for solving the above problems is to provide a method and an apparatus for transmitting and receiving URLLC (Ultra-Reliable and Low Latency Communication) data using resources preempted in the fronthaul. have.

In order to achieve the above object, a method of operating a first communication node according to a first embodiment of the present invention includes transmitting a first control plane message including first resource allocation information of first type data to a second communication node. step, transmitting a first user plane message including the first type data in the resources indicated by the first resource allocation information to the second communication node, when the second type data occurs, the second transmitting, to the second communication node, a second control plane message including second resource allocation information of type data and a preemption indicator indicating that the second type data is transmitted using preempted resources; and sending a second user plane message including the second type data in the preempted resources indicated by two resource allocation information to the second communication node, wherein the preempted resources are the first resources It overlaps with the resources indicated by the allocation information.

Here, the first user plane message, the second control plane message, and the second user plane message may be transmitted to transmit data for generating or processing OFDM symbols transmitted to the user terminal in the same slot, When the second user plane message is transmitted for symbol #k among the symbols constituting the same slot, the second control plane message is transmitted before transmission of the second user plane message for the symbol #k. and the first user plane message may be transmitted before or after transmission of the second user plane message for the symbol #k.

Here, when the transmission of the second user plane message is completed, the remaining user plane messages for the first type data are transmitted after the transmission of the second user plane message is completed, and the second user plane message including the first resource allocation information 1 It can be processed according to the control information indicated by the control plane message.

Here, the second user plane message may further include the preemption indicator.

Here, the preemption indicator may be included in a transport header of the second control plane message.

Here, the preemption indicator may be included in at least one of an application header and a section of the second control plane message.

Here, the preemption indicator may be included in the section extension of the second control plane message.

Here, the first communication node may be an O-DU, the second communication node may be an O-RU, and communication between the O-DU and the O-RU may be performed using the fronthaul interface. have.

Here, the first type data may be eMBB data, and the second type data may be URLLC data.

In order to achieve the above object, a method of operating a first communication node according to a second embodiment of the present invention includes transmitting a first control plane message including first resource allocation information of first type data to a second communication node. step, receiving a first user plane message including the first type data in the resources indicated by the first resource allocation information from the second communication node, when the second type data occurs, the second transmitting, to the second communication node, a second control plane message including second resource allocation information of type data and a preemption indicator indicating that the second type data is transmitted using preempted resources; and receiving, from the second communication node, a second user plane message including the second type data in the preempted resources indicated by second resource allocation information, wherein the preempted resources are the first resource It overlaps with the resources indicated by the allocation information.

Here, the first user plane message, the second control plane message, and the second user plane message may be transmitted to transfer data for OFDM symbols received from a user terminal in the same slot, and the second When a user plane message is transmitted for symbol #k among the symbols constituting the same slot, the second control plane message may be transmitted before transmission of the second user plane message for the symbol #k, The first user plane message may be transmitted before or after transmission of the second user plane message for the symbol #k.

Here, the second user plane message may further include the preemption indicator.

Here, the preemption indicator may be included in a transport header of the second control plane message.

Here, the preemption indicator may be included in at least one of an application header and a section of the second control plane message.

Here, the preemption indicator may be included in the section extension of the second control plane message.

Here, the first communication node may be an O-DU, the second communication node may be an O-RU, and communication between the O-DU and the O-RU may be performed using the fronthaul interface. In addition, the first type data may be eMBB data, and the second type data may be URLLC data.

A second communication node according to a third embodiment of the present invention for achieving the above object includes a processor, a memory in electronic communication with the processor, and instructions stored in the memory, the instructions being executed by the processor , the instructions indicate that the second communication node receives, from the first communication node, a first control plane message including first resource allocation information of first type data, and is indicated by the first resource allocation information. Receive a first user plane message including the first type data from the resources from the first communication node, and use the second resource allocation information of the second type data and the resources to which the second type data is preempted. Receiving a second control plane message including a preemption indicator indicating to be transmitted from the first communication node, and including the second type data in the preempted resources indicated by the second resource allocation information and cause receiving a second user plane message from the first communication node, wherein the pre-empted resources overlap with the resources indicated by the first resource allocation information.

Here, the preemption indicator may be included in a transport header of the second control plane message.

Here, the preemption indicator may be included in at least one of an application header and a section of the second control plane message.

Here, the preemption indicator may be included in the section extension of the second control plane message.

According to the present invention, Ultra-Reliable and Low Latency Communication (URLLC) data in the fronthaul can be transmitted/received based on a preemption method. For example, when transmission of URLLC data is requested during transmission of enhanced Mobile BroadBand (eMBB) data, a control plane message including resource allocation information of URLLC data and a preemption indicator may be transmitted. The preemption indicator may indicate that some resources among resources allocated for eMBB data are preempted for transmission of URLLC data. By using the preemption indicator, the control plane message may not be considered an error message, and the transmission of URLLC data may be supported. Accordingly, the performance of the communication system can be improved.

1 is a conceptual diagram illustrating a first embodiment of a communication system.
2 is a block diagram showing a first embodiment of a communication node constituting a communication system.
3 is a block diagram illustrating a first embodiment of a base station supporting LLS in a communication system.
4 is a conceptual diagram illustrating respective functions of O-DU and O-RU in a communication system.
5 is a flowchart illustrating a first embodiment of a method for transmitting and receiving downlink data in a communication system.
6 is a flowchart illustrating a first embodiment of a method for transmitting and receiving uplink data in a communication system.
7 is a conceptual diagram illustrating a first embodiment of a data transmission method based on a preemption method in a communication system.
8 is a flowchart illustrating a first embodiment of a method for transmitting URLLC data in a communication system.
9 is a flowchart illustrating a second embodiment of a method for transmitting URLLC data in a communication system.

Since the present invention can have various changes and can have various embodiments, specific embodiments are illustrated in the drawings and described in detail. However, this is not intended to limit the present invention to specific embodiments, and it should be understood to include all modifications, equivalents and substitutes included in the spirit and scope of the present invention.

Terms such as first, second, etc. may be used to describe various elements, but the elements should not be limited by the terms. The above terms are used only for the purpose of distinguishing one component from another. For example, without departing from the scope of the present invention, a first component may be referred to as a second component, and similarly, a second component may also be referred to as a first component. and/or includes a combination of a plurality of related listed items or any of a plurality of related listed items.

When a component is referred to as being “connected” or “connected” to another component, it is understood that the other component may be directly connected or connected to the other component, but other components may exist in between. it should be On the other hand, when it is said that a certain element is "directly connected" or "directly connected" to another element, it should be understood that no other element is present in the middle.

The terms used in the present application are only used to describe specific embodiments, and are not intended to limit the present invention. The singular expression includes the plural expression unless the context clearly dictates otherwise. In the present application, terms such as “comprise” or “have” are intended to designate that a feature, number, step, operation, component, part, or combination thereof described in the specification exists, but one or more other features It should be understood that this does not preclude the existence or addition of numbers, steps, operations, components, parts, or combinations thereof.

Unless defined otherwise, all terms used herein, including technical and scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Terms such as those defined in a commonly used dictionary should be interpreted as having a meaning consistent with the meaning in the context of the related art, and should not be interpreted in an ideal or excessively formal meaning unless explicitly defined in the present application. does not

Hereinafter, preferred embodiments of the present invention will be described in more detail with reference to the accompanying drawings. In describing the present invention, in order to facilitate the overall understanding, the same reference numerals are used for the same components in the drawings, and duplicate descriptions of the same components are omitted.

A communication system to which embodiments according to the present invention are applied will be described. The communication system to which the embodiments according to the present invention are applied is not limited to the contents described below, and the embodiments according to the present invention can be applied to various communication systems. Here, a communication system may be used in the same sense as a communication network (network).

1 is a conceptual diagram illustrating a first embodiment of a communication system.

1, the communication system 100 is a plurality of communication nodes (110-1, 110-2, 110-3, 120-1, 120-2, 130-1, 130-2, 130-3, 130-4, 130-5, 130-6). A plurality of communication nodes 4G communication (eg, long term evolution (LTE), LTE-A (advanced)), 5G communication (eg, NR (new radio)) defined in the 3rd generation partnership project (3GPP) standard ) can be supported. 4G communication may be performed in a frequency band of 6 GHz or less, and 5G communication may be performed in a frequency band of 6 GHz or more as well as a frequency band of 6 GHz or less.

For example, a plurality of communication nodes for 4G communication and 5G communication is a CDMA (code division multiple access) based communication protocol, WCDMA (wideband CDMA) based communication protocol, TDMA (time division multiple access) based communication protocol, FDMA (frequency division multiple access) based communication protocol, OFDM (orthogonal frequency division multiplexing) based communication protocol, Filtered OFDM based communication protocol, CP (cyclic prefix)-OFDM based communication protocol, DFT-s-OFDM (discrete) Fourier transform-spread-OFDM) based communication protocol, OFDMA (orthogonal frequency division multiple access) based communication protocol, SC (single carrier)-FDMA based communication protocol, NOMA (Non-orthogonal multiple access), GFDM (generalized frequency) Division multiplexing)-based communication protocol, FBMC (filter bank multi-carrier)-based communication protocol, UFMC (universal filtered multi-carrier)-based communication protocol, SDMA (Space Division Multiple Access)-based communication protocol, etc. can be supported. .

In addition, the communication system 100 may further include a core network. When the communication system 100 supports 4G communication, the core network may include a serving-gateway (S-GW), a packet data network (PDN)-gateway (P-GW), a mobility management entity (MME), and the like. have. When the communication system 100 supports 5G communication, the core network may include a user plane function (UPF), a session management function (SMF), an access and mobility management function (AMF), and the like.

On the other hand, a plurality of communication nodes (110-1, 110-2, 110-3, 120-1, 120-2, 130-1, 130-2, 130-3, 130- 4, 130-5, 130-6) may each have the following structure.

2 is a block diagram showing a first embodiment of a communication node constituting a communication system.

Referring to FIG. 2 , the communication node 200 may include at least one processor 210 , a memory 220 , and a transceiver 230 connected to a network to perform communication. In addition, the communication node 200 may further include an input interface device 240 , an output interface device 250 , a storage device 260 , and the like. Each component included in the communication node 200 may be connected by a bus 270 to communicate with each other.

However, each of the components included in the communication node 200 may not be connected to the common bus 270 but to the processor 210 through an individual interface or an individual bus. For example, the processor 210 may be connected to at least one of the memory 220 , the transceiver 230 , the input interface device 240 , the output interface device 250 , and the storage device 260 through a dedicated interface. .

The processor 210 may execute a program command stored in at least one of the memory 220 and the storage device 260 . The processor 210 may mean a central processing unit (CPU), a graphics processing unit (GPU), or a dedicated processor on which methods according to embodiments of the present invention are performed. Each of the memory 220 and the storage device 260 may be configured as at least one of a volatile storage medium and a non-volatile storage medium. For example, the memory 220 may be configured as at least one of a read only memory (ROM) and a random access memory (RAM).

Referring back to FIG. 1 , the communication system 100 includes a plurality of base stations 110 - 1 , 110 - 2 , 110 - 3 , 120 - 1 and 120 - 2 , and a plurality of terminals 130 - 1, 130-2, 130-3, 130-4, 130-5, 130-6). base station (110-1, 110-2, 110-3, 120-1, 120-2) and terminal (130-1, 130-2, 130-3, 130-4, 130-5, 130-6) The comprising communication system 100 may be referred to as an “access network”. Each of the first base station 110-1, the second base station 110-2, and the third base station 110-3 may form a macro cell. Each of the fourth base station 120-1 and the fifth base station 120-2 may form a small cell. The fourth base station 120-1, the third terminal 130-3, and the fourth terminal 130-4 may belong to the cell coverage of the first base station 110-1. The second terminal 130-2, the fourth terminal 130-4, and the fifth terminal 130-5 may belong to the cell coverage of the second base station 110-2. The fifth base station 120-2, the fourth terminal 130-4, the fifth terminal 130-5, and the sixth terminal 130-6 may belong to the cell coverage of the third base station 110-3. have. The first terminal 130-1 may belong to the cell coverage of the fourth base station 120-1. The sixth terminal 130-6 may belong to the cell coverage of the fifth base station 120-2.

Here, each of the plurality of base stations 110-1, 110-2, 110-3, 120-1, 120-2 is a NodeB (NodeB), an advanced NodeB (evolved NodeB), a base transceiver station (BTS), Radio base station (radio base station), radio transceiver (radio transceiver), access point (access point), access node (node), RSU (road side unit), RRH (radio remote head), TP (transmission point), TRP ( transmission and reception ooint), eNB, gNB, and the like.

Each of the plurality of terminals 130-1, 130-2, 130-3, 130-4, 130-5, 130-6 is a user equipment (UE), a terminal, an access terminal, and a mobile Terminal (mobile terminal), station (station), subscriber station (subscriber station), mobile station (mobile station), portable subscriber station (portable subscriber station), node (node), device (device), Internet of Things (IoT) It may be referred to as a device, a mounted device (such as mounted module/device/terminal or on board device/terminal).

Meanwhile, in a communication system, a base station (eg, eNB, gNB) may support a fronthaul interface. Here, the fronthaul interface may be a fronthaul interface defined in an open-radio access network (O-RAN) alliance. In this case, the base station may be composed of an O-RAN distributed unit (O-DU) and one or more O-RAN radio units (O-RU). Communication between the O-DU and one or more O-RUs may be performed through a fronthaul interface. The fronthaul interface may support mixed numerology. The O-DU may be a lower layer split-central unit (LLS-CU) specified in 3GPP, and the O-RU may be a lower layer split-distributed unit (LLS-DU) specified in 3GPP.

Next, communication methods in the fronthaul will be described. Even when a method (eg, transmission or reception of a signal) performed in a first communication node among communication nodes is described, a corresponding second communication node is a method (eg, a method corresponding to the method performed in the first communication node) For example, reception or transmission of a signal) may be performed. That is, when the operation of the O-DU is described, the corresponding O-RU may perform the operation corresponding to the operation of the O-DU. Conversely, when the operation of the O-RU is described, the corresponding O-DU may perform the operation corresponding to the operation of the O-RU.

3 is a block diagram illustrating a first embodiment of a base station supporting lower layer split (LLS) in a communication system.

Referring to FIG. 3 , the base station 300 may include an O-DU 311 , an O-RU #1 321 , an O-RU #2 322 , and the like. For example, the base station 300 may include a plurality of O-RUs. Communication between the O-DU 311 and the O-RUs 321 and 322 may be performed through a fronthaul interface. The fronthaul interface may include an LLS-control plane and an LLS-user plane.

The O-DU 311 may be a logical node that performs a radio link control (RLC) layer function, a medium access control (MAC) layer function, and a high-physical (PHY) layer function. The O-DU 311 may control the plurality of O-RUs 321 and 322 . Each of the O-RUs 321 and 322 may be a logical node that performs a low-PHY layer function and a radio frequency (RF) processing function. The O-RUs 321 and 322 may transmit/receive control information and/or data by performing communication with the O-DU 311 . The control information may be real-time control information. The data may be user plane data. The O-RUs 321 and 322 may operate based on the control of the O-DU 311 .

4 is a conceptual diagram illustrating respective functions of O-DU and O-RU in a communication system.

Referring to FIG. 4 , the O-DU includes a rate matching function, a coding function, a scrambling function, a modulation function, a layer mapping function, and a precoding function. , a resource element (RE) mapping function, an IQ compression function, and the like. The precoding function may not be performed in a specific mode (eg, bypass mode). For example, when the precoding function is performed in the O-RU, the precoding function may not be performed in the O-DU. The IQ compression function may be selectively performed.

O-RU has OFDM phase compensation function, IQ decompression function, precoding function, digital beamforming function, IFFT (inverse fast Fourier transform) and CP (cyclic prefix) addition function, digital -Analog conversion function, analog beamforming function, etc. can be performed. IQ decompression function, precoding function, digital beamforming function, and analog beamforming function may be selectively performed.

O-RUs may be classified into O-RU category A and O-RU category B. An O-RU belonging to O-RU category A may not support the precoding function. O-RUs belonging to O-RU category B may support the precoding function. Both O-RU category A and O-RU category B may selectively perform a digital beamforming function and/or an analog beamforming function.

Data (eg, user plane data) may be transmitted/received in the fronthaul interface based on RE and/or physical resource block (PRB). In the embodiments below, data may mean "user plane data" or "user plane message", and a message including control information may mean "control plane message". A method of transmitting and receiving downlink data using the fronthaul interface may be as follows.

5 is a flowchart illustrating a first embodiment of a method for transmitting and receiving downlink data in a communication system.

Referring to FIG. 5 , a base station may be configured with an O-DU and one or more O-RUs. Communication between the O-DU and the O-RU(s) may be performed using a fronthaul interface. The O-DU may be the O-DU 311 shown in FIG. 3 and may perform the function(s) shown in FIG. 4 . The O-RU may be the O-RUs 321 and 322 illustrated in FIG. 3 , and may perform function(s) illustrated in FIG. 4 .

The O-DU sends a message (eg, a control plane message) including control information for transmission of data (eg, user plane message) for slot #n using a fronthaul interface before transmission of the corresponding data. It can be transmitted to the O-RU (S501). The O-RU may receive control information from the O-DU through the fronthaul interface. Here, n may be a natural number. The control information may be used to inform the O-RU how to process the data. For example, the control information may include scheduling information, beamforming information, and the like.

One control plane message may include control information for a plurality of user plane messages. A plurality of control plane messages may be transmitted for one slot. Also, a plurality of user plane messages may be transmitted for one slot. When O-RU category A is supported, control plane messages having different extended antenna carrier (eAxC) IDs for each stream may be transmitted. When O-RU category B is supported, control plane messages having different eAxC IDs for each layer may be transmitted. When different numerologies (eg, FFT size, subcarrier (SC) spacing, CP length, etc.) are used, different control plane messages may be used. One control plane message may include a plurality of sections, and different beams may be used for each section.

The O-DU may transmit data for slot #n to the O-RU (S502). The data received by the O-RU in step S502 may be processed based on the control information received in step S501. Each data may include data for each symbol (eg, OFDM symbol #0, #1, #2, ..., #N-1) transmitted in slot #n, and Multiple user plane messages may be sent to N may be a natural number. A control plane message may be transmitted for each slot, and a user plane message associated with the corresponding control plane message may be transmitted in units of symbols. Each data may include IQ data for generation of an OFDM symbol.

When the transmission/reception operation of downlink data for slot #n is completed, the transmission/reception operation of downlink data for slot #n+1 may be performed. For example, in step S503, the O-DU may transmit a message including control information on downlink data for slot #n+1 to the O-RU using the fronthaul interface, and the O-RU Corresponding control information may be received through the hall interface. The data received in step S504 may be processed based on the control information received in step S503. Each data may include data for each symbol transmitted in slot #n+1. For one slot, a plurality of user plane messages may be transmitted from O-DU to O-RU using the fronthaul interface.

6 is a flowchart illustrating a first embodiment of a method for transmitting and receiving uplink data in a communication system.

Referring to FIG. 6 , a base station may be configured with an O-DU and one or more O-RUs. Communication between the O-DU and the O-RU(s) may be performed using a fronthaul interface. The O-DU may be the O-DU 311 shown in FIG. 3 and may perform the function(s) shown in FIG. 4 . The O-RU may be the O-RUs 321 and 322 illustrated in FIG. 3 , and may perform function(s) illustrated in FIG. 4 .

The O-DU transmits a message (eg, control plane message) including control information for transmission of data (eg, user plane message) for slot #n to the O-RU using the fronthaul interface. can be (S601). The O-RU may receive control information from the O-DU through the fronthaul interface. Here, n may be a natural number. The control information may be used to inform the O-RU how to process the data. For example, the control information may include scheduling information, beamforming information, and the like.

One control plane message may include control information for a plurality of user plane messages. A plurality of control plane messages may be transmitted for one slot. Also, a plurality of user plane messages may be transmitted for one slot. If different numerologies are used (eg, FFT size, SC interval, CP length, etc.), different control plane messages may be used. One control plane message may include a plurality of sections, and different beams may be used for each section.

The O-RU may transmit data for slot #n to the O-DU (S602). The data transmitted in step S602 may be processed based on the control information received in step S601. Each data may include data for each symbol (eg, OFDM symbols #0, #1, #2, ..., #N-1) received in slot #n. A plurality of user plane messages may be transmitted for one slot. N may be a natural number. A control plane message may be transmitted for each slot, and a user plane message associated with the corresponding control plane message may be transmitted in units of symbols. The data may include IQ data obtained by the O-RU processing the OFDM symbol received from the user terminal.

When the uplink data transmission/reception operation for the slot #n is completed, the uplink data transmission/reception operation for the slot #n+1 may be performed. For example, in step S603, the O-DU may transmit a message including control information on uplink data for slot #n+1 to the O-RU using the fronthaul interface, and the O-RU Corresponding control information may be received through the hall interface. The data transmitted in step S604 may be processed based on the control information received in step S603. Each data may include data for each symbol received in slot #n+1. A plurality of user plane messages for one slot may be transmitted from the O-RU to the O-DU using the fronthaul interface.

The aforementioned control plane message may include a plurality of sections. Resources using the same beam identifier (eg, beamId) may be included in the same section. The identifier of each of the sections may be a section ID. The section ID may be used for section matching in the user plane message associated with the control plane message. User plane data (eg, user plane message) may include IQ data for generation of OFDM symbols. One user plane message may include IQ data for one OFDM symbol. One control plane message may include control information for a plurality of OFDM symbols.

The 5G communication system may support enhanced Mobile BroadBand (eMBB), Ultra-Reliable and Low Latency Communication (URLLC), and Massive Machine Type Communication (mMTC). In the embodiments below, the eMBB data may be data transmitted/received based on eMBB requirements, the URLLC data may be data transmitted/received based on URLLC requirements, and the mMTC data may be data transmitted/received based on the mMTC requirements. It may be data that is transmitted and received. Low latency requirements can be important in the transmission procedure of URLLC data.

After resources in one slot are scheduled for transmission of specific data (eg, eMBB data), transmission of URLLC data may be requested in resources scheduled for specific data. In this case, some resources from the scheduled resources may be preempted for transmission of URLLC data. That is, when data is transmitted in one slot, some resources may be reallocated for transmission of other data.

7 is a conceptual diagram illustrating a first embodiment of a data transmission method based on a preemption method in a communication system.

Referring to FIG. 7 , frequency band #1 in slot #n may be allocated for eMBB data of UE #1, and frequency band #2 in slot #n may be allocated for eMBB data of UE #2. The base station may transmit the eMBB data to the terminal #1 and the terminal #2 by using the resources allocated in the slot #n. During the transmission of eMBB data, URLLC data for terminal #3 may be generated in the base station. In this case, the base station may reset (eg, reallocate) specific resources for URLLC data in slot #n, and may transmit URLLC data to UE #3 instead of eMBB data using specific resources. That is, specific resources may be reserved for transmission of URLLC data.

When the data transmission method based on the aforementioned preemption method is applied to the fronthaul, the O-DU may transmit a first control plane message including resource allocation information of the first type data to the O-RU. The first control plane message may be transmitted prior to transmission of the user plane message for slot #n. The first type data may be eMBB data. The resource allocation information of the first type data may indicate resources allocated for the first type data in slot #n.

The O-DU may transmit to the O-RU a first user plane message including the first type data to be transmitted by the O-RU to the user terminal in slot #n. During transmission of the first type data, the second type data may be generated in the O-DU. The second type data may be URLLC data. In this case, the O-DU may reconfigure specific resources for the second type data among the resources allocated for the first type data in the slot #n, and use specific resources in the slot #n instead of the first type data The second type data may be transmitted to . In addition, the O-DU may transmit a second control plane message including resource allocation information of the second type data to the O-RU. The resource allocation information included in the second control plane message may indicate specific resources in slot #n. That is, the second control plane message may indicate that specific resources are preempted for transmission of second type data in slot #n.

The O-RU may receive the first control plane message and the second control plane message from the O-DU, and based on the processing result of the first control plane message and the second control plane message, data (eg, For example, a user plane message including first type data and/or second type data) may be obtained. However, according to the O-RAN standard, when different control plane messages (eg, different sections included in different control plane messages) include information on the same resources, different control planes At least one of the messages may be considered an error message. In this case, the data transmission/reception procedure may not be successfully performed.

In the method of transmitting data based on the above-mentioned preemption method, some resources among the resources indicated by the second control plane message are the same as some of the resources among the resources indicated by the first control plane message, so the O-RU is The second control plane message may be considered an error message. In this case, transmission of URLLC data using the fronthaul may not be supported.

When the first control plane message for the first type data and the second control plane message for the second type data are transmitted, in order to support the URLLC data transmission in the fronthaul, the second control plane message does not correspond to an error message. There needs to be a way to tell what isn't. For example, the O-DU may inform that the second control plane message is a control plane message including information of reconfiguration resources (eg, reallocated resources).

8 is a flowchart illustrating a first embodiment of a method for transmitting URLLC data in a communication system.

Referring to FIG. 8 , a base station may be configured with an O-DU and one or more O-RUs. Communication between the O-DU and the O-RU(s) may be performed using a fronthaul interface. The O-DU may be the O-DU 311 shown in FIG. 3 and may perform the function(s) shown in FIG. 4 . The O-RU may be the O-RUs 321 and 322 illustrated in FIG. 3 , and may perform function(s) illustrated in FIG. 4 .

The O-DU may transmit a first control plane message including resource allocation information for slot #n to the O-RU (S801). The first control plane message may be transmitted before the start of slot #n (or before transmission of a specific symbol). The first control plane message includes resource allocation information for first type data (eg, eMBB data) of terminal #1 shown in FIG. 7 and resource allocation for first type data of terminal #2 shown in FIG. 7 . may contain information. The O-RU may receive the first control plane message from the O-DU, and may check resource allocation information included in the first control plane message.

The O-DU may transmit a first user plane message including the first type data for slot #n to the O-RU (S802-1). The first user plane message received by the O-RU in step S802-1 is to be processed based on control information (eg, resource allocation information or data processing method) included in the first control plane message received in step S801. can During transmission of the first type data in the slot #n, the second type data (eg, URLLC data) may occur in the O-DU. In this case, the O-DU transmits the second type data to specific resources (eg, resource elements (REs) or physical resource block (PRB) in symbol #K) among the resources constituting the slot #n. can be reset for The O-DU may transmit a second control plane message including resource allocation information of the second type data to the O-RU (S802-2). The second control plane message may further include a preemption indicator indicating that a preemption operation is enabled. For example, the preemption indicator may indicate that the second type data scheduled by the second control plane message is transmitted in preempted resources according to the preemption scheme. The preemption indicator may be referred to as a “URLLC indicator”.

The second control plane message may be transmitted prior to transmission of the second type of data. For example, the second control plane message may be transmitted before the transmission time of the corresponding second type data in slot #n. After transmitting the second control plane message, the O-DU may transmit second type data (eg, a user plane message) scheduled by the second control plane message to the O-RU (S802-3). The user plane message including the second type data shown in FIG. 7 is transmitted before the O-RU transmits a specific symbol (eg, symbol #K) generated based on the corresponding second type data to the user terminal. can be transmitted. The user plane message transmitted in step S802-3 may further include a preemption indicator indicating that the preemption operation is enabled. For example, the preemption indicator may indicate that the second type data included in the user plane message is transmitted from preempted resources according to the preemption method. The preemption indicator transmitted in step S802-3 may be the same as or similar to the preemption indicator transmitted in step S802-2. When the transmission of the second type data is completed, the O-DU may transmit a user plane message including the remaining first type data for the slot #n to the O-RU (S802-1).

Meanwhile, the O-RU processes the user plane message including the first type data received from the O-DU based on the control information (eg, resource allocation information or data processing method) included in the first control plane message. can do. During reception of the user plane message including the first type data, the O-RU may receive a second control plane message. The O-RU may determine that data scheduled by the second control plane message (eg, second type data) is transmitted according to the preemption method based on the preemption indicator included in the second control plane message. For example, the O-RU transmits data (eg, second type data) of which some resources are different among resources scheduled by the first control plane message based on the preemption indicator included in the second control plane message. It can be judged that it is preempted for Therefore, even if some resources among the resources indicated by the second control plane message are the same as some of the resources indicated by the first control plane message, the O-RU regards the second control plane message as an error message. Instead, the received second user plane message may be processed based on control information (eg, resource allocation information or data processing method) included in the second control plane message.

If "the second control plane message does not include a preemption indicator, and some resources among the resources indicated by the second control plane message are the same as some of the resources indicated by the first control plane message" , the O-RU may regard the second control plane message as an error message, and user plane data received based on control information (eg, resource allocation information or data processing method) included in the first control plane message. can be processed

The O-RU receives the second type data (eg, the second type data from the O-DU) based on the control information (eg, resource allocation information or data processing method) included in the second control plane message. containing user plane messages). Here, the user plane message may further include a preemption indicator as well as the second type data. In this case, the O-RU may determine that the user plane message including the preemption indicator is related to the second control plane message including the preemption indicator. That is, the O-RU may determine that the second type data is transmitted using the preempted resources indicated by the second control plane message. When the reception of the user plane message including the second type data is completed, the O-RU receives the user plane message from the O-DU based on the control information (eg, resource allocation information or data processing method) included in the first control plane message. The remaining first type data received may be processed.

When the data transmission procedure for slot #n is completed, the data transmission procedure for slot #n+1 may be performed. The O-DU and the O-RU may transmit/receive first type data by performing steps S803 and S804. Step S803 may be performed the same or similar to step S801 as described above, and step S804 may be performed identically or similarly to step S802-1 described above.

9 is a flowchart illustrating a second embodiment of a method for transmitting URLLC data in a communication system.

Referring to FIG. 9 , a base station may be configured with an O-DU and one or more O-RUs. Communication between the O-DU and the O-RU(s) may be performed using a fronthaul interface. The O-DU may be the O-DU 311 shown in FIG. 3 and may perform the function(s) shown in FIG. 4 . The O-RU may be the O-RUs 321 and 322 illustrated in FIG. 3 , and may perform function(s) illustrated in FIG. 4 .

The O-DU may transmit a first control plane message including resource allocation information for slot #n to the O-RU (S901). The first control plane message may be transmitted before the start of slot #n (or before reception of a specific symbol). The first control plane message includes resource allocation information for first type data (eg, eMBB data) of terminal #1 shown in FIG. 7 and resource allocation for first type data of terminal #2 shown in FIG. 7 . may contain information. The O-RU may receive the first control plane message from the O-DU, and may check resource allocation information included in the first control plane message.

The O-RU processes the OFDM symbol received from the user terminal in slot #n based on control information (eg, resource allocation information or data processing method) included in the first control plane message to obtain first type data ( For example, a user plane message including the first type data) may be generated, and the user plane message including the first type data may be transmitted to the O-DU ( S902-1 ). The O-DU may receive first type data for slot #n from the O-RU. The O-DU may need to receive second type data (eg, URLLC data) while receiving first type data in slot #n. In this case, the O-DU may reconfigure specific resources (eg, REs or PRBs in symbol #K) among the resources constituting the slot #n for reception of the second type data. The O-DU may transmit a second control plane message including resource allocation information of the second type data to the O-RU (S902-2). The second control plane message may further include a preemption indicator indicating that the preemption operation is enabled. For example, the preemption indicator may indicate that the second type data scheduled by the second control plane message is transmitted in preempted resources according to the preemption scheme.

The second control plane message may be transmitted from the O-DU to the O-RU before a specific symbol (eg, symbol #K) associated with the second type data is received from the user terminal to the O-RU. For example, the second control plane message may be transmitted before symbol #K transmitted from the user terminal in slot #n is received by the O-RU. The O-RU may receive a second control plane message from the O-DU during transmission of the first type data. The O-RU may determine that data scheduled by the second control plane message (eg, second type data) is transmitted according to the preemption method based on the preemption indicator included in the second control plane message. For example, the O-RU transmits data (eg, second type data) of which some resources are different among resources scheduled by the first control plane message based on the preemption indicator included in the second control plane message. It can be judged that it is preempted for Therefore, even if some resources among the resources indicated by the second control plane message are the same as some of the resources indicated by the first control plane message, the O-RU regards the second control plane message as an error message. After processing the OFDM symbol received from the user terminal based on control information (eg, resource allocation information or data processing method) included in the second control plane message, the user plane message including the second type data is generated. and may transmit a user plane message including the second type data to the O-DU.

If "the second control plane message does not include a preemption indicator, and some resources among the resources indicated by the second control plane message are the same as some of the resources indicated by the first control plane message" , the O-RU may regard the second control plane message as an error message, and based on the control information (eg, resource allocation information or data processing method) included in the first control plane message, A processing operation, an operation for generating a user plane message including the first type data, and an operation for transmitting to the O-DU may be performed.

After receiving the second control plane message, the O-RU processes the received OFDM symbol based on the control information (eg, resource allocation information or data processing method) included in the second control plane message, followed by the second type Data (eg, a user plane message including the second type data) may be generated, and the user plane message including the second type data may be transmitted to the O-DU (S902-3). The second type data may be transmitted to the O-DU after the O-RU receives and processes a specific symbol (eg, symbol #K) shown in FIG. 7 . Here, the user plane message may further include a preemption indicator as well as the second type data. In this case, the O-DU receiving the user plane message may determine that the user plane message including the preemption indicator is related to the second control plane message including the preemption indicator. That is, the O-DU may determine that the second type data is transmitted using the preempted resources indicated by the second control plane message, and based on the resource allocation information included in the second control plane message, the second You can check that the type data has been processed properly. When the transmission of the second type data is completed, the O-RU may generate the remaining first type data based on the resource allocation information included in the first control plane message and transmit it to the O-DU (S902-1).

When the data transmission procedure for slot #n is completed, the data transmission procedure for slot #n+1 may be performed. The O-DU and the O-RU may transmit/receive first type data by performing steps S903 and S904. Step S903 may be performed the same or similar to step S901 as described above, and step S904 may be performed the same as or similar to step S902-1 described above.

Meanwhile, in the above-described embodiments shown in FIGS. 8 and/or 9 , the first control plane message (eg, the first control plane message transmitted in step S801 and/or step S901) is the first type data (eg, eMBB data) may include resource allocation information for transmission. The resource allocation information may include resource allocation information for UE #1 and resource allocation information for UE #2. One slot may consist of N symbols, and J+K PRBs may be used for data transmission. For example, J PRBs from among J+K PRBs may be allocated to UE #1, and K PRBs from among J+K PRBs may be allocated to UE #2. UE #1 and UE #2 may use different beams. In a fronthaul message (eg, a control plane message and/or a data plane message), a first section may include information elements for UE #1. In the fronthaul message (eg, control plane message and/or data plane message), the second section may include information elements for terminal #2. The first control plane message may be set as shown in Table 1 below.

After the transmission/reception procedure of the first control plane message defined in Table 1 is completed, first type data (eg, transmitted in step S802-1 shown in FIG. 8 and/or step S902-1 shown in FIG. 9 ) A first user plane message including data of a first type) may be sent. One first user plane message may include IQ data for one symbol. The first user plane message transmitted to transmit data for symbol #n may be set as shown in Table 2 below. n may be one of 0 to N-1, and N may be a natural number.

During the transmission of the first type data, it may be necessary to transmit the second type data (eg, URLLC data) for the terminal #3. In this case, the O-DU may reallocate specific resources (eg, REs or PRBs in symbol #k) allocated for UE #1 and UE #2 to UE #3 in a preemptive manner. The O-DU is a second control plane message (eg, step S802-2 shown in FIG. 8 and/or FIG. 8) including reallocated resource information (eg, resource allocation information for second type data). The second control plane message transmitted in step S902-2 shown in FIG. 9) may be transmitted to the O-RU. The second control plane message may include a preemption indicator as well as resource allocation information.

The preemption indicator may indicate that the preemption operation is enabled. For example, the preemption indicator may indicate that the second type data scheduled by the second control plane message is transmitted in preempted resources according to the preemption scheme. The preemption indicator may be included in an eCPRI transport header, an application common header, and/or a reserved area within a section. Certain information elements in the fronthaul message may be used to indicate preemption indicators. Alternatively, a new information element indicating a preemption indicator may be added to the fronthaul message. The second control plane message may be set as shown in Table 3 below.

After the transmission/reception procedure of the second control plane message defined in Table 3 is completed, the second type data (eg, transmitted in step S802-3 shown in FIG. 8 and/or step S902-3 shown in FIG. 9 ) A second user plane message including the second type data) may be sent. One second user plane message may include IQ data for one symbol. The second user plane message transmitted to transmit data for symbol #K may be set as shown in Table 4 below. After the transmission/reception procedure of the second user plane message is completed, the remaining first user plane messages may be transmitted and processed based on information elements included in the first control plane message.

Meanwhile, the section type of the control plane message provided by the fronthaul interface may be as shown in Table 5 below.

Section type 5 and section type 6 may be types related to each other. The O-RU may generate a beam using scheduled UE information based on the section type 5 message and the section type 6 message and channel information for the corresponding UE(s). When a section type 5 message and a section type 6 message are used, a "UE channel information based real time beamforming method" among beamforming methods may be used. When a section type 1 message or a section type 3 message is used, a beam index transmission method, a real-time weight transmission method, or a beam attribute transmission method may be used among beamforming methods.

Next, a fronthaul message (eg, a control plane message and/or a user plane message) including a preemption indicator will be described. The size of the preemption indicator may be 1 bit or more. If necessary, bit(s) representing additional information may be allocated.

The preemption indicator may be included in an eCPRI transport header, an application common header, and/or a spare area within a section. Certain information elements within the message may be used to indicate preemption indicators. Alternatively, a new information element indicating a preemption indicator may be added to the message.

(1) Method 1: The spare area included in the eCPRI transport header is used for the preemption indicator.

All fronthaul messages may include an eCPRI transport header. The preemption indicator may be allocated to a reserved area of the eCPRI transport header. The eCPRI transport header including the preemption indicator may be configured as shown in Table 6 below. Bits 4-6 of the first octet in the existing eCPRI transport header may be used as ecpriReserved. Some bits (eg, bit 4) of ecpriReserved may be used as a preemption indicator. Based on method 1, a preemption indicator may be added to the control plane message and the user plane message.

(2) Method 2: An application header (eg, application common header) or a spare area included in a section is used for a preemption indicator.

Fields (eg, information elements) included in the application header and/or section may differ depending on the section type. When section type 1 is used, a spare area included in the application header of the control plane message may be used to indicate a preemption indicator. This may be referred to as “Method 2-1”. Method 2-1 may be applied not only to the section type 1 message but also to all fronthaul messages having the same or similar spare area to the spare area of the section type 1 message. Based on method 2-1, the section type 1 message (eg, control plane message) may include information elements defined in Tables 7 to 9 below.

In another embodiment, a specific bit included in a section of a section type 1 message (eg, a control plane message) may be used to indicate a preemption indicator. This may be referred to as “Method 2-2”. When a spare area exists in a section of a section type 1 message, a specific bit in the spare area may be set as a preemption indicator. When a spare area does not exist in a section of a section type 1 message, bit(s) indicating a preemption indicator may be added to the corresponding section. It may be desirable for the fronthaul message to have a 32-bit boundary. When a preemption indicator is added to a section, a 32-bit boundary can be aligned using an additional spare area.

Method 2-2 may be applied not only to the section type 1 message but also to all fronthaul messages having the same or similar spare area to the spare area of the section type 1 message. Based on method 2-2, a section type 1 message (eg, a control plane message) may include information elements defined in Tables 10 to 12 below. For example, a preemption indicator may be added to a section of a section type 1 message, and a 32-bit boundary may be aligned by adding a spare area having a size of 31 bits to the section.

As another embodiment, when a spare area exists in a section type 3 message (eg, a control plane message), a specific bit in the spare area may be used to indicate a preemption indicator. This may be referred to as “Method 2-3”. Based on method 2-3, the section type 3 message may include information elements defined in Tables 13 to 15 below.

In another embodiment, when a section type 0 message (eg, a control plane message) is used, a specific bit of an application header of the section type 0 message and/or a reserved area included in the section may be used to indicate a preemption indicator. can In this case, the preemption indicator may be included in at least one of an application header and a section. This may be referred to as “Method 2-4”. Based on method 2-4, the section type 3 message may include information elements defined in Tables 16 to 18 below.

As another embodiment, when a section type 5 message (eg, a control plane message) is used, a spare area included in an application header of the section type 5 message may be used to indicate a preemption indicator. This may be referred to as “Method 2-5”. Since the reserved area exists in the application header of the section type 5 message, the preemption indicator may be allocated to a specific bit in the reserved area. When using a section type 5 message, relevant channel information may be delivered by a section type 6 message. When preempted data (eg, URLLC data) is transmitted using a section type 5 message, the O-DU transmits a section type 6 message including channel information about the preempted resource before transmission of the section type 5 message. can Based on Method 2-5, the section type 5 message may include information elements defined in Tables 19 to 21 below.

(3) Method 3: Forward the preemption indicator using a newly defined section extension.

A section extension containing additional information for each section can be added to all control plane messages. Section extension including the preemption indicator may be set as shown in Table 22 below. All types of control plane messages (eg, a section type 1 message, a section type 0 message, a section type 3 message, a section type 5 message, and/or a section type 6 message) further extend the section extension defined in Table 22. may include In the existing control plane message, the value of the ef field may be set to 1, and in this state, the existing control plane message may be extended by including the section extension defined in Table 22 in the existing control plane message.

Alternatively, a new section type 8, 9, 10, 11, or 12 message including “existing section type 0, 1, 3, 5, or 6 message + section extension defined in Table 22” may be defined.

In Table 22, extType may indicate a newly defined extension type number (eg, 0x8). In Table 22, extLen may indicate an extended length. For example, extLen may be set to 1. A bit indicating a preemption indicator may be added to the section extension, and a 15-bit reserved area may be set to align a 32-bit boundary.

The methods according to the present invention may be implemented in the form of program instructions that can be executed by various computer means and recorded in a computer-readable medium. The computer-readable medium may include program instructions, data files, data structures, and the like, alone or in combination. The program instructions recorded on the computer-readable medium may be specially designed and configured for the present invention, or may be known and available to those skilled in the art of computer software.

Examples of computer-readable media include hardware devices specially configured to store and carry out program instructions, such as ROM, RAM, flash memory, and the like. Examples of program instructions include not only machine language codes such as those generated by a compiler, but also high-level language codes that can be executed by a computer using an interpreter or the like. The hardware device described above may be configured to operate as at least one software module to perform the operations of the present invention, and vice versa.

Although it has been described with reference to the above embodiments, it will be understood by those skilled in the art that various modifications and changes can be made to the present invention without departing from the spirit and scope of the present invention as set forth in the claims below. will be able

Claims (1)

A method of operating a first communication node in a communication system supporting a fronthaul interface, the method comprising:
transmitting a first control plane message including first resource allocation information of first type data to a second communication node;
transmitting a first user plane message including the first type data in the resources indicated by the first resource allocation information to the second communication node;
When the second type data is generated, the second resource allocation information of the second type data and the second type data including a preemption indicator indicating that the second type data is transmitted using preempted (preempted) resources sending a second control plane message to the second communication node; and
sending a second user plane message including the second type data in the preempted resources indicated by the second resource allocation information to the second communication node;
The method of operation of the first communication node, wherein the preempted resources overlap the resources indicated by the first resource allocation information.

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