Method and apparatus for allocating dynamic resources of an integrated access and backhaul node in a wireless communication system

Abstract

The present disclosure relates to a communication method and system for integrating a fifth generation (5G) communication system for supporting higher data rates beyond a fourth generation (4G) system with technologies for the Internet of Things (IoT). The present disclosure can be applied to intelligent services based on 5G communication technology and IoT-related technologies, such as smart home, smart building, smart city, smart car, connected car, healthcare, digital education, smart retail, security and safety services. The present disclosure discloses a method and apparatus for allocating resources of an IAB node.

Description

Technical Field

[0001] The present disclosure generally relates to wireless communication systems, and more particularly, to methods and apparatuses for dynamic resource allocation for integrated access and backhaul (IAB) nodes. Background Art

[0002] To meet the growing demand for wireless data services since the deployment of fourth-generation (4G) communication systems, efforts have been made to develop improved fifth-generation (5G) or pre-5G communication systems. Therefore, 5G or pre-5G communication systems are also referred to as "beyond 4G networks" or "post-long term evolution (LTE) systems". The 5G communication system is considered to be implemented in a higher frequency (millimeter wave (mmWave)) band (e.g., 60 gigahertz (GHz) band) in order to achieve higher data rates. To reduce the propagation loss of radio waves and increase the transmission distance, beamforming techniques, massive multiple-input multiple-output (MIMO) techniques, full-dimensional MIMO (FD-MIMO) techniques, array antenna techniques, analog beamforming techniques, and massive antenna techniques are discussed in 5G communication systems. In addition, in 5G communication systems, the development of system network improvements is ongoing based on advanced small cells, cloud radio access network (RAN), ultra-dense networks, device-to-device (D2D) communication, wireless backhaul technology, mobile network technology, cooperative communication technology, coordinated multi-point (CoMP) technology, and receiver-side interference cancellation technology. In 5G systems, hybrid frequency shift keying (FSK) and quadrature amplitude modulation (QAM) (FQAM) techniques, sliding window superposition decoding (SWSC) (as an advanced decoding modulation (ACM) technique), filter bank multi-carrier (FBMC) techniques, non-orthogonal multiple access (NOMA) techniques, and sparse code multiple access (SCMA) (as an advanced access technique) have been developed.

[0003] The Internet is now evolving into the Internet of Things (IoT), in which distributed entities in the IoT can exchange and process information without human intervention. As a combination of IoT technology and big data processing technology through connection to a cloud server, the Internet of Everything (IoE) has emerged. Since technical elements such as "sensing technology", "wired / wireless communication and network infrastructure", "service interface technology", and "security technology" are required for IoT implementation, sensor networks, machine-to-machine (M2M) communication technology, and machine type communication (MTC) technology have been recently studied. Such an IoT environment can provide intelligent Internet technology services, which create new value for human life by collecting and analyzing data generated among connected things. IoT can be applied to various fields including smart home, smart building, smart city, smart car or connected car, smart grid, healthcare field, smart home appliances, and advanced medical services through the integration and combination of existing information technology and various industrial applications.

[0004] To apply the 5G communication system to the IoT network, various attempts have been made. For example, technologies (such as sensor network technology, MTC technology, and M2M communication technology) can be implemented through beamforming, MIMO, and array antennas. Cloud RAN, as an application of the big data processing technology described above, can also be regarded as an example of the integration between 5G technology and IoT technology.

[0005] In addition, various studies have been conducted to utilize IAB technology, and thus it is also necessary to improve the resource allocation of IAB nodes. Summary of the Invention

[0006] Technical Problem

[0007] In the next-generation communication system, it is necessary to enhance the IAB operation of IAB nodes.

[0008] Technical Solution

[0009] This disclosure is made to solve the problems and disadvantages mentioned above and at least provide the advantages described below.

[0010] According to an aspect of the present disclosure, there is provided a method performed by an IAB node including a distributed unit (DU) and a mobile terminal (MT). The method includes: receiving, by the MT, from a base station a message configuring at least one slot format for the MT; receiving, by the MT, from the base station downlink control information (DCI) including a slot format indicator indicating a slot format from at least one slot format; and communicating, by the MT, with a network node in a slot based on the slot format indicated by the slot format indicator, where the slot includes 14 orthogonal frequency division multiplexing (OFDM) symbols having indices from 0 to 13, where the slot format includes a start portion, a middle portion, and an end portion, the start portion includes at least one uplink symbol, the middle portion includes at least one flexible symbol, the end portion includes at least one downlink symbol, and where the slot format is identified from a first slot format group including 8 or more flexible symbols, a second slot format group including 9 or more uplink symbols, a third slot format group including 8 or more downlink symbols, or a fourth slot format group including 6 uplink symbols and 6 flexible symbols or 6 downlink symbols.

[0011] According to another aspect of the present disclosure, a method performed by a base station including a Central Unit (CU) and a Distributed Unit (DU) is provided. The method includes: transmitting, by the DU, a message for configuring at least one slot format for an Inter-Access-Backhaul (IAB) node to the IAB node; transmitting, by the DU, a Downlink Control Information (DCI) to the IAB node, the DCI including a slot format indicator indicating a slot format from at least one slot format; and communicating, by the DU and the IAB node, in a slot based on the slot format indicated by the slot format indicator, where the slot includes 14 Orthogonal Frequency Division Multiplexing (OFDM) symbols having indexes from 0 to 13, where the slot format includes a start portion, a middle portion, and an end portion, the start portion includes at least one uplink symbol, the middle portion includes at least one flexible symbol, the end portion includes at least one downlink symbol, and where the slot format is identified from a first slot format group including 8 or more flexible symbols, a second slot format group including 9 or more uplink symbols, a third slot format group including 8 or more downlink symbols, or a fourth slot format group including 6 uplink symbols and 6 flexible symbols or 6 downlink symbols.

[0012] According to another aspect of the present disclosure, an IAB node including a DU and a Mobile Terminal (MT) is provided. The IAB node includes: a transceiver configured to transmit and receive signals; and a controller configured to: receive, by the MT, a message for configuring at least one slot format for the MT from a base station; receive, by the MT, a DCI from the base station, the DCI including a slot format indicator indicating a slot format from at least one slot format; and communicate, by the MT and a network node, in a slot based on the slot format indicated by the slot format indicator, where the slot includes 14 OFDM symbols having indexes from 0 to 13, where the slot format includes a start portion, a middle portion, and an end portion, the start portion includes at least one uplink symbol, the middle portion includes at least one flexible symbol, the end portion includes at least one downlink symbol, and where the slot format is identified from a first slot format group including 8 or more flexible symbols, a second slot format group including 9 or more uplink symbols, a third slot format group including 8 or more downlink symbols, or a fourth slot format group including 6 uplink symbols and 6 flexible symbols or 6 downlink symbols.

[0013] According to another aspect of the present disclosure, a base station including a CU and a DU is provided. The base station includes: a transceiver configured to transmit and receive signals; and a controller configured to: transmit, by the DU, a message for configuring at least one slot format for an IAB node to the IAB node; transmit, by the DU, DCI to the IAB node, the DCI including a slot format indicator indicating a slot format from at least one slot format; and communicate, by the DU with the IAB node in a slot based on the slot format indicated by the slot format indicator, where the slot includes 14 OFDM symbols having indices from 0 to 13, where the slot format includes a start portion, a middle portion, and an end portion, the start portion including at least one uplink symbol, the middle portion including at least one flexible symbol, the end portion including at least one downlink symbol, and where the slot format is identified from a first slot format group including 8 or more flexible symbols, a second slot format group including 9 or more uplink symbols, a third slot format group including 8 or more downlink symbols, or a fourth slot format group including 6 uplink symbols and 6 flexible symbols or 6 downlink symbols.

[0014] Advantageous effects of the invention

[0015] According to various embodiments of the present disclosure, IAB operations of IAB nodes can be efficiently enhanced. Brief description of the drawings

[0016] In the following description with reference to the accompanying drawings, the above and other aspects, features, and advantages of certain embodiments of the present disclosure will become more apparent, in which:

[0017] Figure 1 is a view illustrating a communication system in which an IAB operates according to an embodiment;

[0018] Figure 2 is a view schematically illustrating multiplexing in the time domain and frequency domain between an access link and a backhaul link in an IAB according to an embodiment;

[0019] Figure 3 is a view illustrating multiplexing in the time domain between an access link and a backhaul link in an IAB according to an embodiment;

[0020] Figure 4 is a view illustrating multiplexing in the frequency domain and spatial domain between an access link and a backhaul link in an IAB according to an embodiment;

[0021] Figure 5 is a view illustrating the structure of an IAB node according to an embodiment;

[0022] Figure 6is a view showing problems that occur when applying dynamic resource allocation for IAB;

[0023] Figure 7 is a view showing a terminal device according to an embodiment;

[0024] Figure 8 is a view showing a base station device according to an embodiment; and

[0025] Figure 9 is a view showing a device of an IAB node according to an embodiment. Detailed Description of the Invention

[0026] The present disclosure proposes a method for solving problems that occur when the transmission / reception directions of the DU and MT in an IAB node do not match during the operation of the IAB. In addition, the present disclosure proposes a time slot format for the smooth operation of the IAB node.

[0027] According to an embodiment of the present disclosure, when the data transmission / reception directions of the DU and MT of the IAB node do not match, the operation of the IAB node is defined according to the unidirectional transmission / reception characteristics, thereby avoiding problems that may occur in the IAB node. In addition, the IAB node can perform efficient communication based on the time slot format proposed for the operation of the IAB node.

[0028] Various embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. However, in the drawings, the same or similar elements are designated by the same or similar reference numerals as much as possible. In addition, detailed descriptions of known functions or configurations may be omitted.

[0029] When describing embodiments of the present disclosure, descriptions related to technical content well known in the art and not directly related to the present disclosure may be omitted. Such omission of unnecessary descriptions is intended to prevent confusion of the main idea of the present disclosure.

[0030] Similarly, in the drawings, some elements may be exaggerated or schematically illustrated. In addition, the size of each element may not fully reflect the actual size. In the drawings, the same or corresponding elements may be provided with the same reference numerals.

[0031] The advantages and features of the present disclosure and the ways to implement them will be apparent by referring to the embodiments described in detail below in conjunction with the accompanying drawings. However, the present disclosure is not limited to the embodiments set forth below, but can be implemented in various different forms. Only the following embodiments are provided to fully disclose the present disclosure and inform those skilled in the art of the scope of the present disclosure, and the present disclosure is only limited by the scope of the appended claims. Throughout the specification, the same or similar reference numerals designate the same or similar elements.

[0032] Here, it will be understood that aspects of the present disclosure may be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, a special purpose computer, or other programmable data processing apparatus to produce a machine, such that the instructions, which may be executed via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the present disclosure. These computer program instructions may also be stored in a computer-usable or computer-readable memory, which may direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-usable or computer-readable memory produce an article of manufacture including instruction means that implement the functions specified in one or more flowchart blocks. The computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer-implemented process, such that the instructions, when executed on the computer or other programmable apparatus, provide steps for implementing the functions specified in the present disclosure.

[0033] In addition, each block in the flowchart illustrations may represent a module, segment, or portion of code, which includes one or more executable instructions for implementing the specified logical function(s). It should also be noted that in some alternative implementations, the functions noted in the present disclosure may occur out of the order noted.

[0034] As used herein, the term "unit" refers to a software element or a hardware element that performs a predetermined function, such as a field programmable gate array (FPGA) or an application specific integrated circuit (ASIC). However, the meaning of "unit" is not always limited to software or hardware. A "unit" may be configured to be stored in an addressable storage medium or to execute on one or more processors. Thus, a "unit" includes, for example, software elements, object-oriented software elements, class elements or task elements, processes, functions, attributes, procedures, subroutines, program code segments, drivers, firmware, microcode, circuits, data, databases, data structures, tables, arrays, and parameters. The elements and functions provided by a "unit" may be combined into fewer elements or a single "unit", or be divided into a greater number of elements or a single "unit". In addition, the elements and "units" may be implemented to reproduce one or more CPUs within a device or a secure multimedia card.

[0035] Wireless communication systems have evolved from early voice-oriented services to broadband wireless communication systems that provide high-speed and high-quality packet data services according to communication standards such as the 3rd Generation Partnership Project (3GPP) High-Speed Packet Access (HSPA) standard, Long-Term Evolution (LTE) or Evolved Universal Terrestrial Radio Access (E-UTRA) standard, Advanced LTE (LTE-A) standard, LTE-Pro standard, 3GPP2 (3GPP2) High-Speed Packet Data (HRPD) standard, Ultra Mobile Broadband (UMB) standard, and Institute of Electrical and Electronics Engineers (IEEE) 802.16e standard.

[0036] As a representative example of a broadband wireless communication system, in an LTE system, the OFDM scheme is adopted in the downlink, and the Single-Carrier Frequency Division Multiple Access (SC-FDMA) scheme is adopted in the uplink. The uplink is the radio link by which a terminal, user equipment (UE), or mobile station (MS) transmits data or control signals to a base station, while the downlink is the radio link by which the base station transmits data or control signals to a terminal. In this multiple access method, the data or control information of each user is typically divided by performing dispatching and operations such that the time-frequency resources for the data or control information to be carried for each user do not overlap, that is, such that orthogonality is established.

[0037] As a future communication system after LTE, since the 5G (or New Radio (NR)) communication system should be able to freely reflect various requirements of users and service providers, it should support services that can meet various requirements simultaneously. Enhanced Mobile Broadband (eMBB), Massive Machine-Type Communication (mMTC), and Ultra-Reliable Low-Latency Communication (URLLC) are services considered for the 5G communication system.

[0038] The eMBB service aims to provide a data rate faster than that supported by existing LTE, LTE-A, or LTE-Pro services. For example, in a 5G communication system, from the perspective of a base station, eMBB should be able to provide a maximum transmission rate of 20 Gigabits per second (Gbps) in the downlink and 10 Gbps in the uplink. In addition, the 5G communication system should provide the maximum transmission rate and, at the same time, should provide an increased user-perceived terminal data rate. To meet these requirements, various transmission / reception technologies need to be improved, including more advanced multi-antenna (Multiple-Input Multiple-Output (MIMO)) transmission technologies. In addition, when the 5G communication system transmits signals using a maximum transmission bandwidth of 20 Megahertz (MHz) in the 2 GHz frequency band currently used by LTE, it uses a frequency bandwidth wider than 20 MHz in the 3 to 6 GHz or 6 GHz and higher frequency bands, thereby meeting the data transmission speed required in the 5G communication system.

[0039] In addition, the use of mMTC is being considered to support application services in 5G communication systems, such as IoT. To efficiently provide IoT, mMTC is required to support large-scale terminal access within a cell, improve terminal coverage, extend battery life, and reduce terminal costs. IoT has various sensors and various devices attached to it to provide communication functions and support a large number of terminals within a cell (e.g., 1,000,000 terminals per square kilometer (km2)). In addition, since terminals supporting mMTC are very likely to be located in shadow areas not covered by the cell due to the characteristics of the service, such as the basement of a building, a wider coverage range than other services provided by the 5G communication system is required. Since terminals supporting mMTC should be configured as low-cost terminals and since the batteries of the terminals are difficult to replace frequently, a very long battery life, such as 10 to 15 years, is required.

[0040] Finally, URLLC is a cellular-based wireless communication service used for mission-critical purposes. For example, its use can be considered in services related to remote control for robots or machinery, industrial automation, drones, telemedicine, and emergency alerts. Therefore, the communication provided by URLLC should support very low latency and very high reliability. For example, a service supporting URLLC should satisfy an air interface latency of less than 0.5 milliseconds and also have a -5 packet error rate of 10 or less. Therefore, for services supporting URLLC, the 5G system should provide a smaller transmission time interval (TTI) than other services and, to ensure the reliability of the communication link, should allocate wider resources in the frequency band.

[0041] The three 5G services (i.e., eMBB, URLLC, and mMTC) can be multiplexed and transmitted in one system. In this case, different transmission / reception techniques and transmission / reception parameters can be used between the services to meet the different requirements of each service.

[0042] In 5G, when a base station transmits and receives data to and from a terminal in a 6 GHz band or higher band (especially the mmWave band), the coverage range may be limited due to the attenuation of the propagation path. The above problem of limited coverage can be solved by closely placing multiple relay nodes between the propagation paths of the base station and the terminal, but the cost of installing optical cables for backhaul connections between the relays becomes expensive. Therefore, instead of installing optical cables between the relays, the broadband radio frequency resources available in mmWave are used to transmit and receive backhaul data between the relays, thus solving the cost problem associated with installing optical cables and using the mmWave band more efficiently.

[0043] As described above, the technology of using mmWave to transmit and receive backhaul data from the base station and ultimately transmit and receive access data to / from the terminal through multiple relays is called IAB. At this time, the relay node that transmits and receives data from the base station through the wireless backhaul is called an IAB node. In this case, the base station consists of a CU and a DU, and the IAB node consists of a DU and an MT. The CU manages the DUs of all IAB nodes connected to the base station through multiple hops.

[0044] The IAB node uses the same frequency band when receiving backhaul data from the base station and transmitting access data to the terminal and when receiving access data from the terminal and transmitting backhaul data to the base station. Due to the characteristics of the IAB node, the IAB node has a half-duplex constraint at any given moment. Therefore, as a method for reducing the transmission / reception delay caused by the unidirectional transmission / reception characteristics of the IAB node, when the IAB node is receiving, the backhaul data (downlink data from the DU of the parent IAB node to the MT of the IAB node and uplink data from the MT of the child IAB node to the DU of the IAB node) and the access data from the terminal (upstream data from the terminal to the IAB node) can be multiplexed and received in a frequency-division multiplexing (FDM) and / or space-division multiplexing (SDM) method.

[0045] In addition, when the IAB node is transmitting, the backhaul data (uplink data from the MT of the IAB node to the DU of the parent IAB node and downlink data from the DU of the IAB node to the MT of the child IAB node) and the access data to the terminal (downlink data from the IAB node to the terminal) can be multiplexed and transmitted using FDM and / or SDM. In this case, when the data transmission / reception directions of the DU and the MT in the IAB node do not match, it is necessary to define the operation of the IAB node according to the unidirectional transmission / reception characteristics. Therefore, in the present disclosure, the operation of the IAB node is provided.

[0046] Figure 1 is a view illustrating a communication system that operates IAB.

[0047] In Figure 1Among them, gNB 101 is a typical base station (such as an eNB or a gNB), and is referred to as a base station or a donor base station in this disclosure. IAB Node #1 111 and IAB Node #2 121 are IAB nodes that transmit and receive backhaul links in the mmWave band. The terminal (i.e., UE) 1 102 transmits and receives access data through gNB 101 and access link 103. IAB Node #1 111 transmits and receives backhaul data through gNB 101 and backhaul link 104. The terminal 2 112 transmits and receives access data through IAB Node #1 111 and access link 113. IAB Node #2 121 transmits and receives backhaul data through IAB Node #1 111 and backhaul link 114. Therefore, IAB Node #1 111 is a higher IAB node of IAB Node #2 121, and is also referred to as a Parent IAB node. IAB Node #2 121 is a lower IAB node of IAB Node #1 111, and is referred to as a Child IAB node. The terminal 3 122 transmits and receives access data through IAB Node #2 121 and access link 123.

[0048] Next, the measurement of the donor gNB for the IAB node or the terminal will be described.

[0049] When the terminal 2 112 or the terminal 3 122 performs measurements on a donor gNB or an IAB node that is not the serving IAB node but a neighboring donor gNB or an IAB node, coordination between the donor gNB and the IAB node may be required. That is, the donor gNB matches the measurement resources of the IAB node with an even number of hops or the measurement resources of the IAB node with an odd number of hops, so that the terminal does not waste resources when measuring neighboring IAB nodes or IAB base stations. The terminal can receive the configuration for measuring the synchronization signal block (SSB) / physical broadcast channel (PBCH) or the channel state information reference signal (CSI-RS) from the serving IAB node or base station through a high-layer signal to measure neighboring IAB nodes. If the terminal receives the configuration for measuring a neighboring base station through SSB / PBCH, then in the terminal, at least two SSB / PBCH measurement timing configurations (SMTCs) / frequencies can be configured for each measurement resource of the IAB node with an even number of hops or for each measurement resource of the IAB node with an odd number of hops. The terminal that receives the SMTC configuration can perform measurements on the IAB node with an even number of hops in one SMTC, and can perform measurements on the IAB node with an odd number of hops in another SMTC.

[0050] Next, the measurement of other IAB nodes for the IAB node or the donor gNB will be described.

[0051] To enable an IAB node to measure a donor gNB or an IAB node in another neighbor, coordination between the donor gNB and the IAB node may be required. That is, the donor gNB matches the measurement resources of the IAB nodes with an even number of hops or the measurement resources of the IAB nodes with an odd number of hops, so that the resource waste for one IAB node when measuring neighboring IAB nodes or IAB base stations can be minimized. An IAB node can receive the configuration for measuring SSB / PBCH or CSI-RS for neighboring IAB nodes from the serving IAB node or base station through a high-layer signal. If the IAB node receives the configuration for measuring neighboring base stations through SSB / PBCH, then in the IAB node, at least two SMTC / frequencies can be configured for each measurement resource of the IAB nodes with an even number of hops or for each measurement resource of the IAB nodes with an odd number of hops. The IAB node that receives the SMTC configuration can perform the measurement of the IAB nodes with an even number of hops in one SMTC, and can perform the measurement of the IAB nodes with an odd number of hops in another SMTC.

[0052] Next, in the IAB technology proposed in the present disclosure, the multiplexing of the backhaul link between the base station and the IAB node or between the first IAB node and the second IAB node and the multiplexing of the access link between the base station and the terminal or between the IAB node and the terminal within the radio resources will be described in more detail with reference to Figure 2 、 3 and 4.

[0053] Figure 2 is a view schematically illustrating the multiplexing between the access link and the backhaul link in IAB. Specifically, Figure 2 the upper part of Figure 2 illustrates that the IAB node is multiplexed in the time domain between the access link and the backhaul link.

[0054] In Figure 2 the radio resource 201 shown at the upper part of

[0055] Next, in Figure 2In the radio resources 211 shown in the lower part of [Figure / Illustration], the backhaul link 213 between the base station and the IAB node or between the first IAB node and the second IAB node and the access link 212 between the base station and the terminal or between the IAB node and the terminal are multiplexed in the frequency domain (i.e., using FDM). Therefore, data can be transmitted and received between the base station and the IAB node in the time domain when the base station or the IAB node transmits and receives data to and from the terminal, but due to the unidirectional transmission and reception characteristics of the IAB node, data transmission can only be performed in the same direction. That is, in the time domain when an IAB node receives data from the terminal, the IAB node can only receive backhaul data from another IAB node or the base station. In addition, in the time domain when an IAB node transmits data to the terminal, the IAB node can only transmit backhaul data to another IAB node or the base station.

[0056] In Figure 2 only TDM and FDM are described, but other types of multiplexing (i.e., SDM) in the spatial domain between the access link and the backhaul link are possible. Therefore, the access link and the backhaul link can be transmitted and received simultaneously through SDM, but like the FDM at the bottom of Figure 2 due to the unidirectional transmission / reception characteristics of the IAB node, data transmission can only be performed in the same direction in SDM. That is, in the time domain when an IAB node receives data from the terminal, the IAB node can only receive backhaul data from another IAB node or the base station. In addition, in the time domain when an IAB node transmits data to the terminal, the IAB node can only transmit backhaul data to another IAB node or to the base station.

[0057] Regarding which multiplexing scheme among TDM, FDM, and SDM described above is adopted, when the IAB node initially accesses the base station or a higher IAB node, the IAB node can transmit the ability of the multiplexing scheme to the base station or the higher IAB node, and then receive the same information from the corresponding base station or the higher IAB node through the system information or the radio resource control (RRC) signal. Alternatively, it can be received from the base station or the higher IAB node through the backhaul link after the initial access. The multiplexing scheme can support at least one of TDM, FDM, and SDM.

[0058] Next, Figure 3 is a view illustrating the multiplexing in the time domain between the access link and the backhaul link in the IAB.

[0059] Figure 3 The upper part of [Figure / Illustration] illustrates the process in which the IAB node 302 communicates with the parent IAB node 301, the child IAB node 303, and the terminal 304. In a more detailed description of the link between the nodes, the parent IAB node 301 is in the backhaul downlink (L P,DL)Transmit the backhaul downlink signal to the IAB node 302 in the middle, and the IAB node 302 transmits the backhaul uplink signal to the parent IAB node 301 in the backhaul uplink (L P,UL )The IAB node 302 transmits the access downlink signal to the terminal 304 in the access downlink (L A,DL ), and the terminal 304 transmits the access uplink signal to the IAB node 302 in the access uplink (L A,UL ). The IAB node 302 transmits the backhaul downlink signal to the child IAB node 303 in the backhaul downlink (L C,DL ), and the IAB child node 303 transmits the backhaul uplink signal to the IAB node 302 in the backhaul uplink (L C,UL ). In the above notations, "P" represents the backhaul link with the parent, "A" represents the access link with the terminal, "C" represents the backhaul link with the child, "DL" represents the downlink, and "UL" represents the uplink.

[0060] This link relationship is described based on the IAB node 302. From the perspective of the IAB child node 303, the node in the parent node relationship is the IAB node 302, and the IAB child node 303 may have another IAB child node in a lower layer. In addition, from the perspective of the parent IAB node 301, the node in the child node relationship is the IAB node 302, and the parent IAB node 301 may have another IAB parent node in a higher layer.

[0061] As discussed above, the signal includes data and control information, the channel for transmitting data and control information, the reference signal required for decoding data and control information, or the reference signal providing channel information.

[0062] Figure 3 The lower part of the figure illustrates the process in which all the above links are multiplexed in the time domain. The backhaul downlink (L P,DL ) 311, the backhaul downlink (L C,DL ) 313, the access downlink (L A,DL ) 316, the access uplink (L A,UL ) 315, the backhaul uplink (L C,UL ) 314, and the backhaul uplink (L P,UL ) 312 are multiplexed in a time series. The relationship between the links provided in the figure is an example, and any other relationship between the links can be applied.

[0063] Since the above - mentioned link is sequentially multiplexed in the time domain, it can be seen that this is the multiplexing scheme with the longest time for transmitting signals from the parent IAB node 301 via the IAB node 302 to the child IAB node 303 and also to the terminal. Therefore, as a method for reducing the delay when finally transmitting signals from the parent IAB node 301 to the terminal, methods such as multiplexing two backhaul links in the frequency domain or multiplexing a backhaul link and an access link or multiplexing in the spatial domain before simultaneous transmission can be considered.

[0064] Figure 4 It is a view showing the multiplexing in the frequency domain and spatial domain between the access link and the backhaul link in the IAB.

[0065] will be referred to Figure 4 to describe the method for reducing the time delay by multiplexing two backhaul links or multiplexing a backhaul link and an access link in the frequency domain or spatial domain.

[0066] Similar to Figure 3 , at the upper part of Figure 4 , the process of the IAB node 402 communicating with the parent IAB node 401, the child IAB node 403, and the terminal 404 is illustrated. In a more detailed description of the links between each node, the parent IAB node 401 transmits a backhaul downlink signal to the IAB node 402 in the backhaul downlink (L P,DL ), and the IAB node 402 transmits a backhaul uplink signal to the parent IAB node 401 in the backhaul uplink (L P,UL ). The IAB node 402 transmits an access downlink signal to the terminal 404 in the access downlink (L A,DL ), and the terminal 404 transmits an access uplink signal to the IAB node 402 in the access uplink (L A,UL ). The IAB node 402 transmits a backhaul downlink signal to the child IAB node 403 in the backhaul downlink (L C,DL ), and the IAB sub - node 403 transmits a backhaul uplink signal to the IAB node 402 in the backhaul uplink (L C,UL ). In the above notations, "P" represents the backhaul link with the parent, "A" represents the access link with the terminal, "C" represents the backhaul link with the child, "DL" represents the downlink, and "UL" represents the uplink.

[0067] This link relationship is described based on the IAB node 402. From the perspective of the IAB child node 403, the node in the parent node relationship is the IAB node 402, and the IAB child node 403 may have another IAB child node in a lower layer. In addition, from the perspective of the parent IAB node 401, the node in the child node relationship is the IAB node 402, and the parent IAB node 401 may have another IAB parent node in a higher layer.

[0068] As described above, the signal includes data and control information, a channel for transmitting data and control information, a reference signal required for decoding data and control information, or a reference signal for providing channel information.

[0069] Figure 4 The lower part of the figure illustrates a scheme for multiplexing the links described above in the frequency domain or the spatial domain.

[0070] As described above, since the IAB node has unidirectional transmission / reception characteristics at any given moment, the signals that can be multiplexed in the frequency domain or the spatial domain are limited. For example, when considering the unidirectional transmission / reception characteristics of the IAB node 402, the links that can be multiplexed in the time domain in which the IAB node can perform transmission are the backhaul uplink (L P,UL ) 412, the backhaul downlink (L C,DL ) 413, or the access downlink (L A,DL ) 416. Therefore, when the links are multiplexed in the frequency domain or the spatial domain, the IAB node 402 can transmit all the links in the same time domain (such as in 421). In addition, the links that can be multiplexed in the time domain in which the IAB node can receive are the backhaul downlink (L P,DL ) 411, the backhaul uplink (L C,UL ) 414, the access uplink (L A,UL ) 415, etc. Therefore, when the links are multiplexed in the frequency domain or the spatial domain, the IAB node 402 can receive all the links in the same time domain (as shown in 422).

[0071] The multiplexing of the links provided in the figure is an example, and it goes without saying that only two of the three links multiplexed in the frequency domain or the spatial domain can be multiplexed.

[0072] Next, the structure of the IAB node will be described.

[0073] In 5G, to support various services (such as, high-capacity transmission, low latency, high reliability, or a large number of IoT devices) and reduce the communication network installation cost (capital expenditure (CAPEX)), various types of base station structures most suitable for service requirements have been studied. In 4G LTE, to reduce CAPEX and effectively handle interference control, the cloud RAN (C-RAN) structure has been commercialized. In this cloud RAN structure, the data processing unit of the base station and the radio transmission / reception unit (or remote radio head (RRH)) are separated. The data processing unit is processed centrally, and only the radio transmission / reception unit is placed at the cell site. In the C-RAN structure, when transmitting baseband digital IQ data from the base station data processing unit to the radio transmission / reception unit, an optical link conforming to the Common Public Radio Interface (CPRI) standard is generally used. When data is transmitted to such a radio transmission / reception unit, a high data transmission rate is required. For example, a data transmission rate of 614.4 Mbps is required when transmitting 10 MHz Internet Protocol (IP) data, and a data transmission rate of 1.2 Gbps is required when transmitting 20 MHz IP data.

[0074] Therefore, in the 5G RAN structure, to relieve the huge load on the optical link, the base station is divided into a CU and a DU, and functional split is applied to the CU and the DU to achieve various structures. In 3GPP, the standardization of various functional split options between the CU and the DU is being promoted, and the options for functional split are divided according to the functions between protocol layers or within protocol layers, and there are a total of 8 options from option 1 to option 8. Among them, scenarios 2 and 7 are the structures first considered in the current 5G base station structure. In option 2, the Radio Resource Control (RRC) and Packet Data Convergence Protocol (PDCP) are located in the CU, and the Radio Link Control (RLC), Medium Access Control (MAC), Physical layer, and Radio Frequency (RF) are located in the DU. In option 7, the RRC, PDCP, RLC, MAC, and higher Physical layer are located in the CU, and the lower Physical layer is located in the DU. A structure with configuration flexibility can be adopted, in which the NR network protocol is separated and moved between the CU and the DU through the functional split as described above. Through this structure, flexible hardware implementation provides a cost-effective solution, and the separated structure between the CU and the DU enables adjustment of load management, real-time performance optimization, and Network Function Virtualization (NFV) / Software Defined Networking (SDN), and this configurable functional split has the advantage of being applicable to various applications (variable latency in transmission).

[0075] Reference will be made to Figure 5 describe the structure of the IAB node considering the split function. Figure 5 is a view schematically illustrating the structure of the IAB node.

[0076] In Figure 5In [description], gNB 501 consists of a CU and a DU, and the IAB node consists of a terminal function (or MT) for transmitting and receiving data on the parent node and the backhaul link and a base station function (or DU) for transmitting and receiving data on the child node and the backhaul link. In Figure 5 In [description], IAB node #1 502 is wirelessly connected to gNB 501 through one hop, and IAB node #2 503 is wirelessly connected to gNB 501 through two hops via IAB node #1 502.

[0077] As Figure 5 As shown in [description], the CU of gNB 501 not only controls (via 511 and 512) the DU of gNB 501, but also controls all IAB nodes wirelessly connected to gNB 501, that is, the DUs of IAB node #1 502 and IAB node #2 503. The CU can allocate radio resources to the DU so that the DU can transmit and receive data with the MT of the IAB node in the lower layer. The allocation of radio resources can be transmitted to the DU through system information, high-layer signals, or physical signals using the F1 application protocol (F1AP) interface. In this case, the radio resources can consist of downlink time resources, uplink time resources, and flexible time resources.

[0078] Hereinafter, the radio resource configuration will be described in detail based on IAB node #2 503. The downlink time resource is a resource for transmitting downlink control / data and signals from the DU of IAB node #2 503 to the MT of the IAB node. The uplink time resource is a resource for receiving uplink control / data and signals from the MT of the IAB node lower than the DU. The flexible time resource is a resource that can be used by the DU as a downlink time resource or an uplink time resource, and how the flexible time resource will be used can be indicated to the MT of the lower IAB node through the downlink control signal of the DU. After receiving the downlink control signal, the MT determines whether the flexible time resource will be used as a downlink time resource or an uplink time resource. When no downlink control signal is received, the MT does not perform transmission / reception operations. That is, the MT does not monitor, decode, or measure signals from resources in the downlink control channel. Among the above resources, the MT does not perform transmission / reception operations. That is, the MT does not monitor, decode, or measure signals from resources in the downlink control channel. For the downlink time resource, uplink time resource, and flexible time resource, two different types (or three different types including time resources that are not always available) of resources can be indicated from the CU to the DU.

[0079] The first type of resources is a soft type, and the CU can use F1AP (i.e., the interface between the CU and the DU) to set soft-type downlink time resources, uplink time resources, and flexible time resources for the DU of the IAB node #2 503. In this case, for the configured soft-type resources, the IAB node #1 as the parent IAB (or the DU of the parent IAB) of the IAB node #2 503 can explicitly (e.g., through the DCI format) or implicitly indicate whether the above resources are available or unavailable to the IAB node #2, which is the child IAB (or the DU of the child IAB). That is, when it is indicated that a specific resource is available, the DU of the IAB node #2 503 can use the resource for data transmission / reception with the MT of the lower IAB node. That is, the DU of the IAB node #2 503 can use the resource to perform transmission in the case of downlink resources or can perform reception in the case of uplink resources. If the resource is indicated to be unavailable, the IAB node #2 503 cannot use the resource for data transmission / reception with the MT of the lower IAB node. That is, the DU of the IAB node #2 503 cannot be transmitted or received using the resource.

[0080] The method of indicating the availability of soft type resources based on the DCI format will be described in more detail.The DCI format in this embodiment may include an availability indicator for indicating the availability of one or more consecutive uplink, downlink or flexible symbols.

[0081] In order to receive the DCI format, the IAB node #2 503 may receive in advance, through a high-layer signal from the CU or the parent IAB, at least one or more of the position information of the availability indicator indicating the availability of the IAB node #2, the table indicating the availability of time resources corresponding to a plurality of time slots, and information on a mapping relationship of the availability indicator from the DCI format together with the cell ID of the DU of the IAB node #2 503. The value (or indicator) indicating the availability of consecutive uplink symbols, downlink symbols, or flexible symbols within one time slot and the meaning of the value (or indicator) may be configured as shown in the following Table 1, where "DL" refers to downlink and "UL" refers to uplink.

[0082]

Table 1

[0083] Value Indication 0 No resource availability 1 DL resource available 2 UL resource available 3 DL and UL resources available 4 Flexible resource available 5 DL and flexible resources available 6 UL and flexible resources available 7 DL, UL and flexible resources available

[0084] When the above-mentioned availability indicator is indicated from the parent IAB to the IAB node #2 503 according to the DCI format and the IAB node #2 receives the indication, the following method can be considered as a method for interpreting the relationship between the downlink, uplink or flexible time resources configured by the DU of the IAB node #2 503 from the CU to the IAB DU and the aforementioned availability.

[0085] The first method is a method in which the number of values of the availability indicator included in the DCI format in the IAB DU is expected to match the number of time slots including the soft type resources composed of consecutive symbols configured by the CU. According to this method, it can be determined that the IAB DU is only applied to the time slots including the soft type resources.

[0086] The second method is that the number of values of the availability indicator included in the DCI format of the IAB DU is expected to match the number of all time slots configured by the CU (that is, the number of all time slots including hard / soft / unavailable (NA) types). At the same time, the IAB DU can determine that the availability is only applied to the time slots including the soft type, and can determine that the indicated utilization rate is not applied to the time slots including only the hard or NA type without the soft type.

[0087] In the first and second methods, the IAB DU can expect that the value indicating the availability matches the downlink resource, uplink resource, or flexible resource configured by the CU. For example, when there are only downlink soft resources or downlink hard resources in a time slot, it can be expected that only the value 1 in Table 1 above can be indicated for the IAB DU. Therefore, it can be expected that the values including the availability of the uplink soft resources among the values in the above table are not indicated.

[0088] Alternatively, the IAB DU can determine that in addition to indicating the value that the flexible resource is available in the flexible resources set by the CU, it can also indicate whether the downlink resource or the uplink resource is available. For example, in the case of flexible soft resources or flexible hard resources, it can be expected that the DU of the IAB node can indicate the value 1 or 2 instead of the value 4 in Table 1 above. In this case, according to the instruction of the parent IAB, it can be determined that the DU of the IAB node #2 can only use the uplink resource or the downlink resource, rather than using the flexible resource as the uplink resource or the downlink resource when judged by the IAB node #2.

[0089] Alternatively, the IAB DU is expected to indicate the value 0 in Table 1 in any hard / soft or NA resources set by the CU. In this case, the IAB DU determines that resource utilization is impossible in the hard / soft resources previously set by the CU, and the IAB DU assumes that the DU of the IAB node #2 is not available for data transmission or reception with the MT of the lower IAB node until it is indicated to be available by the DCI format, as in the case of the always unavailable resource type configured by the CU. Thereafter, when the availability is indicated again by the DCI format, the DU of the IAB node #2 can set the resource through the CU and utilize it when received by the DCI format.

[0090] The second type of resource is a hard type of resource, and the above resources are always utilized between the DU and the MT. That is to say, the DU of IAB node #2 can perform transmission when the resource is a downlink time resource, regardless of the transmission / reception operations of the MT of IAB node #2, and can perform reception when the resource is an uplink resource. When the resource is a flexible resource, the transmission or reception is performed according to the determination of the IAB DU (that is to say, the determination can be to match the DCI format that indicates whether the flexible resource is a downlink resource or an uplink resource to the MT of the lower IAB node).

[0091] The third type of resource is a resource that is always unavailable (always unused or always non - available), and the above resource is not available for the DU of IAB node #2 to perform data transmission and reception with the MT.

[0092] When downlink time resources, uplink time resources, flexible time resources, and reserved time resources are received from the CU to the DU as high - layer signals, the above types of resources are received together.

[0093] Next, the DU of gNB 501 is a typical base station, and the DU controls the MT of IAB node #1 502 to perform scheduling for transmitting and receiving data 521. The DU of IAB node #1 502 is a conventional base station, and the DU controls the MT of IAB node #2 503 to perform scheduling so that data can be transmitted and received 522.

[0094] Based on the radio resources allocated from the CU, the DU can indicate the radio resources so that data can be transmitted and received with the MT of the lower IAB node. The configuration of the radio resources can be transmitted to the MT through system information, high - layer signals, or physical signals. In this case, the radio resources can be composed of downlink time resources, uplink time resources, flexible time resources, and reserved time resources. The downlink time resource is a resource for transmitting downlink control / data and signals to the MT of the IAB node lower than the DU. The uplink time resource is a resource for receiving uplink control / data and signals from the MT of the IAB node lower than the DU.

[0095] The flexible time resource is a resource that can be used by the DU as a downlink time resource or an uplink time resource, and how the flexible time resource will be used can be indicated to the MT of the lower IAB node by the downlink control signal of the DU. After receiving the downlink control signal, the MT determines whether the flexible time resource will be used as a downlink time resource or an uplink time resource. When no downlink control signal is received, the MT does not perform transmission / reception operations. That is to say, the MT does not monitor, decode, or measure the signals from the resources in the downlink control channel.

[0096] The downlink control signal is signaled to the MT by a combination of a high-layer signal and a physical signal, and the MT can determine the slot format in a specific time slot by receiving the signaling. The slot format usually starts with a downlink symbol, has a flexible symbol in the middle, and ends with an uplink symbol (that is, has a structure of downlink-flexible-uplink (DFU) order). When only using the above slot format, the DU of the IAB node can perform downlink transmission at the start of the time slot, but the MT of the IAB node is only configured with the above slot format (i.e., DFU structure) from the parent IAB. Therefore, uplink transmission cannot be performed simultaneously (corresponding to slot format indices 0 to 55 in Table 2 below). Therefore, a slot format configured to start with an uplink symbol, place a flexible symbol in the middle, and end with a downlink symbol can be defined as shown in Table 2 below (corresponding to slot format indices 56 to 82 in Table 2 below). The slot format defined in Table 2 is transmitted to the MT using the downlink control signal and can be configured from the CU to the DU using F1AP. In Table 2, "D" is a downlink symbol, "U" is an uplink symbol, and "F" is a flexible symbol.

[0097] [Table 2]

[0098]

[0099]

[0100] The reserved time resource is a resource where the MT below the DU cannot transmit / receive data, and the MT does not perform transmission / reception operations in this resource. That is, the MT does not monitor, decode, or measure the signals from the resources in the downlink control channel.

[0101] Therefore, the MT in an IAB node is controlled by the DU in a higher IAB node to receive scheduling information for transmitting and receiving data, and the DU in the same IAB node is controlled by the CU of the gNB 501, so that the MT and DU in an IAB are controlled by different entities, making it difficult to perform coordination in real time.

[0102] Figure 6 It is a view showing the problems that occur when applying dynamic resource allocation for IAB.

[0103] Figure 6 It shows Figure 5 the state where the DU of IAB node #1 according to Figure 5 indicates the above resources to the MT of IAB node #2 and the CU of the gNB provides an instruction for resource allocation to the DU of IAB node #2, as Figure 6As shown in 601, both the DU and MT of IAB node #2 receive the same time resources as the flexible time resources. In this case, the MT of IAB node #2 determines the flexible time resources as downlink time resources or uplink time resources according to the instructions of the DU of IAB node #1. Subsequently, the MT of IAB node #2 can receive the downlink control / data channel and reference signals when determining the flexible time resources as downlink time resources according to the scheduling, or can transmit the uplink control / data channel and reference signals when determining the flexible time resources as uplink time resources. On the other hand, the DU of IAB node #2 can instruct the MT of the lower IAB node to determine the flexible time resources as uplink time resources and transmit the uplink control / data channel and reference signals, or can execute the instructions for receiving the downlink control / data channel and reference signals by determining the downlink time resources.

[0104] Therefore, according to the indication of the DU of IAB node #1 and the determination of the DU of IAB node #2, each of the MT and DU in IAB node #2 should determine and execute the transmission / reception in the flexible time resources. There may be cases where the one-way transmission / reception characteristics of the IAB node cannot be satisfied. For example, the MT of IAB node #2 can determine the flexible time resources as downlink time resources according to the indication of the DU of IAB node #1 to receive the downlink control / data channel and reference signals, and at the same time, the DU of IAB node #2 can transmit the downlink control / data channel and reference signals by determining the flexible time resources as downlink time resources. Therefore, when the MT of IAB node #2 needs to receive and transmit the DU, the one-way transmission / reception characteristics cannot be satisfied.

[0105] Therefore, in the present disclosure, a solution is provided for transmitting and receiving data on the backhaul link while satisfying the one-way transmission / reception characteristics of the IAB node when a conflict occurs between the transmission / reception of the MT and DU in the IAB node.

[0106] According to an embodiment, in Figure 6 when the DU of IAB node #1 has been assigned a specific time resource as a soft type from the CU and the time resource is not utilized by the DU of the parent IAB node (that is, IAB node #1), Figure 6 the MT of IAB node #2 determines that the time resource is not used for transmission / reception, so IAB node #2 can transmit and receive data by only considering the DU. That is, for the one-way transmission / reception characteristics, IAB node #2 can transmit / receive the DU of IAB node #2 without considering the transmission / reception of the MT of IAB node #2. Therefore, IAB node #2 can prioritize the transmission and reception of the DU over the transmission and reception of the MT.

[0107] Alternatively, when the DU of IAB node #2 is assigned as a specific time resource of the soft type from the CU, and the MT of the sub-IAB node explicitly or implicitly indicates not to use this time resource, IAB node #2 can consider only the MT for transmitting and receiving data. That is, for the unidirectional transmission / reception characteristic, IAB node #2 can transmit / receive the MT according to the scheduling of the DU of IAB node #1, without considering the transmission / reception of the DU of IAB node #2.

[0108] In addition, when one or more of the following conditions are met, the embodiments can be applied:

[0109] Condition 1 is the following: The DU of IAB node #1 is assigned as a specific time resource of the soft type from the Figure 6 CU therein, and this time resource is explicitly or implicitly instructed to the Figure 6 MT of IAB mode #2 such that this time resource is used by the DU of IAB node #1 which is the parent IAB node, such that the MT of IAB node #2 determines that this time resource is used for transmitting and receiving, or the DU of IAB node #1 is assigned as a specific time resource of the hard type from the CU; and / or

[0110] Condition 2 is the following: The DU of IAB node #2 is assigned as a specific time resource of the soft type from the CU, and the MT of the sub-IAB node can be explicitly or implicitly instructed to use this time resource, and alternatively, the DU of IAB node #2 is assigned as a specific time resource of the hard type from the CU.

[0111] If IAB node #2 determines that both Condition 1 and Condition 2 above are satisfied, then IAB node #2 can receive both the DU and MT of IAB node #2 in this time resource only when the MT of IAB node #2 is reception and the DU of IAB node #2 is reception, or the DU and MT of IAB node #2 can be transmitted simultaneously in this time resource only when the MT of IAB node #2 is transmission and the DU of IAB node #2 is transmission.

[0112] If IAB node #2 determines that both Condition 1 and Condition 2 are satisfied simultaneously, then according to the unidirectional transmission and reception characteristic of the IAB node, when the MT of IAB node #2 is transmission, the DU of IAB node #2 is reception or the MT of IAB node #2 is reception and the DU of IAB node #2 is transmission, IAB node #2 performs the transmission / reception of only one of the DU or MT.

[0113] In addition, the embodiments can be applied to implement a method of performing the transmission / reception of only one of the DU or MT.

[0114] The IAB node can determine whether to prioritize the transmission and reception of the DU or MT based on the priority rules. Therefore, when the transmission and reception of the DU or MT in an IAB node need to be performed simultaneously, which link transmission power or transmission should be prioritized can be determined based on the transmission channel or transmission information of the DU or MT, as Figure 6 described. For example, the priority rules for the transmission channel or transmission information can be determined as follows.

[0115] The first priority can include the synchronization signal, the tracking reference signal (TRS) for estimating the phase of the channel, or the synchronization signal or CSI-RS transmitted for discovering the IAB node.

[0116] The second priority can include the uplink control information, which includes the hybrid automatic repeat request acknowledgment (HARQ-ACK).

[0117] The third priority can include the uplink data channel, which includes the HARQ-ACK.

[0118] The fourth priority can include the downlink control information, the downlink data information, and / or the CSI-RS.

[0119] Therefore, the first priority can be the channel or information that should be prioritized, and the importance decreases compared to the next priority. The above priority rules are examples, and which information or channel should be prioritized can be determined differently, and the transmission priority as described above can be determined according to the standard. In the above, when the transmission power is limited, the transmission power is given first, or the transmission is always performed. On the contrary, not being prioritized means that when the transmission power is limited, the transmission power is reduced compared to the priority level, or the transmission is discarded.

[0120] The transmission channel or transmission information is the channel or information that can be transmitted in the backhaul uplink (L P,UL ) 412, the backhaul downlink (L C,DL ) 413, and the access downlink (L A,DL ) 416, and when the same channel or information is transmitted on two different links, the backhaul link may have priority, or the access link may have priority. In addition, the transmission waveform of the link can be configured as cyclic prefix (CP)-OFDM or discrete Fourier transform spread (DFT-S)-OFDM through high-layer signaling or X2 signaling. In the above case, when two different links are transmitted with different waveforms, DFT-S-OFDM may have priority over CP-OFDM.

[0121] A channel or link containing priority information gives priority to the MT or DU of the IAB node in terms of transmission power or transmission, and is transmitted and received, while other DUs or MTs that are not transmitted / received discard the transmission / reception.

[0122] As another priority rule, the transmission / reception with the parent IAB node can always be prioritized. That is, the MT of an IAB node can be prioritized. In this case, the DU of the IAB node should discard the transmission / reception with the MT of the child IAB node, or should be avoided through scheduling.

[0123] Alternatively, the transmission and reception with the child IAB node can always be prioritized as another priority rule. That is, a DU of an IAB node can be prioritized. In this case, the MT of the IAB node should discard the scheduling by the DU of the parent IAB node or the transmission / reception as instructed.

[0124] To implement the above embodiments, Figure 7 illustrates the transmitter, receiver, and controller of a terminal, and Figure 8 illustrates the transmitter, receiver, and controller of a base station. In addition, Figure 9 illustrates the device of an IAB node. When transmitting and receiving a backhaul link or an access link through an IAB node in a 5G communication system, it shows the base station (or donor base station) that performs transmission to and reception from the IAB node and the backhaul link through mmWave, and the transmission / reception method between the terminal that transmits / receives the IAB node and the access link.

[0125] Specifically, Figure 7 is a block diagram illustrating the internal structure of a terminal according to an embodiment. As Figure 7 shown, the terminal includes a terminal controller 701, a terminal receiver 702, and a terminal transmitter 703.

[0126] The terminal controller 701 can control a series of processes that the terminal can operate. For example, the transmission and reception of the access link with the IAB node can be controlled differently. The terminal receiver 702 and the terminal transmitter 703 can be collectively referred to as a transceiver. The transceiver can transmit and receive signals with the base station. The signals can include control information and data. For this purpose, the transceiver can include an RF transmitter that up-converts and amplifies the frequency of the transmitted signal and an RF receiver that amplifies the received signal with low noise and down-converts the frequency. In addition, the transceiver can receive signals through a wireless channel and output the signals to the terminal controller 701, and transmit the signals output from the terminal controller 701 through the wireless channel.

[0127] Figure 8is a block diagram illustrating the internal structure of a base station (donor base station) according to an embodiment. As Figure 8 shown, the base station includes a base station controller 801, a base station receiver 802, and a base station transmitter 803.

[0128] The base station controller 801 can control a series of processes so that the base station can operate. For example, the base station controller 801 can control the transmission and reception of the backhaul link with the IAB node differently from the transmission and reception of the access link of the IAB node. The base station receiver 802 and the base station transmitter 803 can be collectively referred to as a transceiver. The transceiver can transmit and receive signals with a terminal. The signals can include control information and data. To this end, the transceiver can include an RF transmitter that up-converts and amplifies the frequency of the transmitted signal and an RF receiver that amplifies the received signal with low noise and down-converts the frequency. In addition, the transceiver can receive signals through a wireless channel and output the signals to the base station controller 801, and transmit the signals output from the base station controller 801 through the wireless channel.

[0129] Figure 9 is a block diagram illustrating the internal structure of an IAB node according to an embodiment. As Figure 9 shown, the IAB node of the present disclosure includes a base station function controller 901, a base station function receiver 902, and a base station function transmitter 903 of the IAB node for performing transmission and reception with a lower IAB node through a backhaul link. The base station function controller 901, the base station function receiver 902, and the base station function transmitter 903 can be understood as the DU function or the DU part described above.

[0130] In addition, the IAB node can include a terminal function controller, a terminal function receiver 912, and a terminal function transmitter 913 of the IAB node for initial access to a higher IAB node and a donor base station, transmitting and receiving higher signals before transmitting and receiving through the backhaul link, and transmitting and receiving the backhaul link with the higher IAB node and the donor base station. The terminal function controller 911, the terminal function receiver 912, and the terminal function transmitter 913 can be understood as the MT function or the MT part described above.

[0131] The base station function controller 901 of the IAB node may control a series of processes so that the IAB node can operate like a base station. For example, the base station function controller 901 may perform the functions of the DU of the IAB node described above. The base station function controller 901 may control the transmission and reception of the backhaul link with the lower IAB node differently from the transmission and reception of the access link of the terminal. The base station function receiver 902 and the base station function transmitter 903 may be collectively referred to as a transceiver. The transceiver may transmit and receive signals with the lower IAB node and the terminal. The signals may include control information and data. To this end, the transceiver may include an RF transmitter that up-converts and amplifies the frequency of the transmitted signal and an RF receiver that amplifies the received signal with low noise and down-converts the frequency. In addition, the transceiver may receive a signal through a wireless channel, output the signal to the base station function controller 901, and transmit the signal output from the base station function controller 901 through the wireless channel.

[0132] The terminal function controller 911 of the IAB node may control a series of processes in which the lower IAB node can operate like a terminal to transmit and receive data with the donor base station or the higher IAB node, and may perform the MT function of the IAB node described above. For example, the terminal function controller 911 may control the transmission and reception of the backhaul link with the donor base station and the higher IAB node. The terminal function receiver 912 and the terminal function transmitter 913 may be collectively referred to as a transceiver. The transceiver may transmit and receive signals with the donor base station and the higher IAB node. The signals may include control information and data. To this end, the transceiver may include an RF transmitter that up-converts and amplifies the frequency of the transmitted signal and an RF receiver that amplifies the received signal with low noise and down-converts the frequency. In addition, the transceiver may receive a signal through a wireless channel and output the signal to the terminal function controller 911, and transmit the signal output from the terminal function controller 911 through the wireless channel.

[0133] Figure 9 The base station function controller 901 of the IAB node and the terminal function controller 911 of the IAB node included in the IAB node may be integrated with each other to be implemented as an IAB node controller 900. In this case, the IAB node controller 900 may control the functions of the DU and the MT together in the IAB node.

[0134] Although the present disclosure has been specifically shown and described with reference to certain embodiments of the present disclosure, those of ordinary skill in the art will understand that various changes may be made in form and detail without departing from the spirit and scope of the present disclosure as defined by the appended claims and their equivalents.

Claims

1. A method performed by an integrated access and backhaul (IAB) node including a distributed unit (DU) and a mobile terminal (MT) in a communication system, the method comprises: receiving, by the MT, downlink control information (DCI) for identifying a time slot format from at least one time slot format; and communicating, by the MT, in a time slot based on the time slot format, wherein one time slot includes 14 orthogonal frequency division multiplexing (OFDM) symbols having indices from 0 to 13, wherein the at least one time slot format is configured based on a first time slot format set and a second time slot format set, wherein the first time slot format set is defined by a first table below: wherein the second time slot format set is defined by a second table below: wherein in the first table and the second table, D is a downlink symbol, U is an uplink symbol, and F is a flexible symbol, wherein for a specific time resource for which the DU of the IAB node is configured as a soft type, in a case where the MT does not perform transmission or reception in the specific time resource, the DU performs transmission or reception in the specific time resource, and wherein the specific time resource is one of a downlink symbol, an uplink symbol, and a flexible symbol.

2. The method according to claim 1, wherein the MT and the DU are respectively configured with their own time slot formats, and wherein the time slot format for the DU is configured via F1 application protocol (F1AP) signaling.

3. The method according to claim 1, wherein based on information indicating the soft type received by the DU via F1AP signaling, the specific time resource is configured as the soft type.

4. A method performed by a base station in a communication system, the method comprises: transmitting, to an integrated access and backhaul (IAB) node, downlink control information (DCI) including information about a time slot format from at least one time slot format for a mobile terminal (MT) of the IAB node; and communicating, based on the time slot format, in a time slot, wherein one time slot includes 14 orthogonal frequency division multiplexing (OFDM) symbols having indices from 0 to 13, wherein the at least one time slot format is configured based on a first time slot format set and a second time slot format set, wherein the first time slot format set is defined by a first table below: wherein the second time slot format set is defined by a second table below: wherein in the first table and the second table, D is a downlink symbol, U is an uplink symbol, and F is a flexible symbol, wherein for a specific time resource for which the DU of the IAB node is configured as a soft type, in a case where transmission or reception has not occurred for the MT in the specific time resource, transmission or reception is available for the distributed unit (DU) of the IAB node in the specific time resource, and wherein the specific time resource is one of a downlink symbol, an uplink symbol, and a flexible symbol.

5. The method according to claim 4, further comprising sending information about the time slot format for the DU via F1 application protocol (F1AP) signaling.

6. The method according to claim 4 further includes sending, via F1AP signaling, information indicating the soft type to the DU to configure the specific time resource as the soft type.

7. An integrated access and backhaul (IAB) node in a wireless communication system, the IAB node including a distributed unit (DU) and a mobile terminal (MT), comprising: a transceiver; and a processor, coupled to the transceiver and configured to: receive, from the MT, downlink control information (DCI) for identifying a slot format from at least one slot format, and communicate in a slot based on the slot format by the MT, wherein one slot includes 14 orthogonal frequency division multiplexing (OFDM) symbols having indexes from 0 to 13, wherein the at least one slot format is configured based on a first set of slot formats and a second set of slot formats, wherein the first set of slot formats is defined by the following first table: wherein the second set of slot formats is defined by the following second table: wherein, in the first table and the second table, D is a downlink symbol, U is an uplink symbol, and F is a flexible symbol, wherein, for a specific time resource for which the DU of the IAB node is configured as the soft type, in a case where the MT does not perform transmission or reception in the specific time resource, the DU performs transmission or reception in the specific time resource, and wherein the specific time resource is one of a downlink symbol, an uplink symbol, and a flexible symbol.

8. The IAB node according to claim 7, wherein the MT and the DU are respectively configured with their own slot formats, and wherein the slot format for the DU is configured via F1 application protocol (F1AP) signaling.

9. The IAB node according to claim 7, wherein based on the information indicating the soft type received by the DU via F1AP signaling, the specific time resource is configured as the soft type.

10. A base station in a communication system, the base station comprising: a transceiver; and a processor, coupled to the transceiver and configured to: transmit downlink control information (DCI) including information about a slot format from at least one slot format of a mobile terminal (MT) for an integrated access and backhaul (IAB) node to the IAB node, and communicate in a slot based on the slot format, wherein one slot includes 14 orthogonal frequency division multiplexing (OFDM) symbols having indexes from 0 to 13, wherein the at least one slot format is configured based on a first set of slot formats and a second set of slot formats, wherein the first set of slot formats is defined by the following first table: wherein the second set of slot formats is defined by the following second table: wherein, in the first table and the second table, D is a downlink symbol, U is an uplink symbol, and F is a flexible symbol, Among them, for the DU of the IAB node, it is configured as a specific time resource of the soft type. When transmission or reception has not occurred for the MT in the specific time resource, transmission or reception is available for the distributed unit DU of the IAB node in the specific time resource, and Among them, the specific time resource is one of a downlink symbol, an uplink symbol, and a flexible symbol.

11. The base station according to claim 10, Among them, the processor is further configured to send information about the time slot format for the DU via F1 application protocol F1AP signaling.

12. The base station according to claim 10, Among them, the processor is further configured to send information indicating the soft type to the DU via F1AP signaling to configure the specific time resource as the soft type.

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