CN116783950A - Method and apparatus for performing communication for transmission of IAB node in wireless communication system - Google Patents

Abstract

Methods and apparatus are provided for transmitting signals by an Integrated Access and Backhaul (IAB) node including an integrated access and backhaul mobile terminal (IAB-MT) and an integrated access and backhaul (IAB-DU) Distributed Unit (DU) via a backhaul link between a parent IAB node and a child IAB node in a wireless communication system. The method comprises the following steps: receiving signaling information indicating a timing scheme to be applied to the IAB-MT from a parent IAB node; and transmitting, by the IAB-MT, a signal to the parent IAB node in the backhaul uplink and transmitting, by the IAB-DU, a signal to the child IAB node in the backhaul downlink, in a case where the indicated timing scheme is a first timing scheme in which the transmission timing of the IAB-MT coincides with the transmission timing of the IAB-DU, wherein the transmission timing at which the IAB-MT transmits the signal and the transmission timing at which the IAB-DU transmits the signal are set identically.

Description

Method and apparatus for performing communication for transmission of IAB node in wireless communication system

Technical Field

The present disclosure relates to wireless communication systems. More particularly, the present disclosure relates to methods and apparatus for performing communications in an Integrated Access and Backhaul (IAB) node.

Background

In order to meet the rapid increase in demand for wireless data traffic since the fourth generation (4G) communication systems became available, efforts are continually being made to develop enhanced fifth generation (5G) communication systems or pre-5G (pre-5G) communication systems. For this reason, the 5G communication system or the pre-5G communication system is also called a super 4G network communication system or a Long Term Evolution (LTE) after-system.

In order to obtain a higher transmission rate, it is considered to implement the upper 5G communication system at an ultra-high frequency band (millimeter (mm) wave), for example, at 60 GHz. In order to alleviate the path loss on the ultra-high frequency band and increase the arrival range of radio waves, the following technique is considered for the 5G communication system: beamforming, massive multiple-input multiple-output (MIMO), full-dimensional MIMO (FD-MIMO), array antennas, analog beamforming, and massive antennas.

Various techniques for 5G communication systems with enhanced networks are also under development, such as evolved or advanced small cells, cloud radio access networks (cloud RANs), ultra dense networks, device-to-device (D2D) communications, wireless backhaul, active networks, cooperative communications, coordinated multipoint (CoMP), and interference cancellation.

There are various other schemes under development for 5G systems, such as hybrid Frequency Shift Keying (FSK) and Quadrature Amplitude Modulation (QAM) (FQAM) as well as Sliding Window Superposition Coding (SWSC) as Advanced Code Modulation (ACM) schemes, and Filter Bank Multicarrier (FBMC), non-orthogonal multiple access (NOMA) and Sparse Code Multiple Access (SCMA) as advanced access schemes.

The internet is evolving from an artificially-centered, connected network that is established by humans and consumes information to the internet of things (IoT) that communicates and processes information between things or other distributed components. Another technology is internet of everything (IoE), which is a combination of big data processing technology and IoT technology through, for example, a connection with a cloud server.

In order to implement IoT, technical elements such as sensing technology, wired/wireless communication and network infrastructure, service interface technology, and security technology are required. There are recent ongoing studies on inter-object connection technologies such as sensor networks, machine-to-machine (M2M) or Machine Type Communication (MTC).

Intelligent Internet Technology (IT) services may be provided in IoT environments that collect and analyze data generated by interconnected things, creating new value for human life. Through the conversion or integration of existing Information Technology (IT) technology and various industries, ioT may have various applications such as smart homes, smart buildings, smart cities, smart or networked automobiles, smart grids, health or smart home appliance industries, or state-of-the-art medical services.

Accordingly, various attempts are being made to use 5G communication systems for IoT. For example, 5G communication techniques such as sensor networks, M2M, and MTC may be implemented by techniques including beamforming, MIMO, and array antennas. Applying the cloud RAN as the big data processing technique described above may be regarded as an example of aggregation between 5G technology and IoT technology.

Recently, various researches have been made to utilize Integrated Access and Backhaul (IAB) technology, and accordingly there is a need to improve dual access of an IAB node.

The foregoing information is provided merely as background information to aid in the understanding of the disclosure. As to whether any of the above is suitable as prior art with respect to the present disclosure, no decision has been made nor is any claim made.

Disclosure of Invention

[ problem ]

Aspects of the present disclosure are to address at least the problems and/or disadvantages described above and to provide at least the advantages described below. Accordingly, one aspect of the present disclosure is to provide a communication method and apparatus for efficient transmission of Integrated Access and Backhaul (IAB) nodes in a wireless communication system.

Another aspect of the present disclosure is to provide a communication method and apparatus for enabling efficient transmission of an IAB node, which is a Radio Access Network (RAN) node supporting a new air interface (NR) backhaul link for an IAB node, which is different from an NR access link for a User Equipment (UE), in a wireless communication system.

Another aspect of the present disclosure is to provide a communication method and apparatus in a wireless communication system in which a Distributed Unit (DU) included in an IAB node and a Mobile Terminal (MT) simultaneously transmit signals to a parent IAB node or a child IAB node in different resources.

Another aspect of the present disclosure is to provide a communication method and apparatus in a wireless communication system that facilitates interference cancellation in a parent IAB node and a child IAB node when the parent IAB node and the child IAB node receive signals transmitted simultaneously by the IAB nodes in different resources.

Another aspect of the present disclosure is to provide a communication method and apparatus in a wireless communication system that aligns slot timing between a DU and an MT during signaling of the DU and the MT included in an IAB node.

Additional aspects will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the presented embodiments.

[ technical solution ]

According to an aspect of the present disclosure, there is provided a method for transmitting a signal by an integrated access and backhaul mobile terminal (IAB-MT) and an integrated access and backhaul (IAB-DU) Distributed Unit (DU) via a backhaul link between a parent IAB node and a child IAB node in a wireless communication system. The method comprises the following steps: receiving signaling information indicating a timing scheme to be applied to the IAB-MT from a parent IAB node; and transmitting, by the IAB-MT, a signal to the parent IAB node in the backhaul uplink and transmitting, by the IAB-DU, a signal to the child IAB node in the backhaul downlink, in a case where the indicated timing scheme is a first timing scheme in which a transmission timing of the IAB-MT coincides with a transmission timing of the IAB-DU, wherein the transmission timing at which the IAB-MT transmits the signal and the transmission timing at which the IAB-DU transmits the signal are set identically (identity).

According to another aspect of the present disclosure, there is provided an IAB node for transmitting a signal via a backhaul link between a parent IAB node and a child IAB node in a wireless communication system. The IAB node comprises: an IAB-MT configured to receive signaling information from a parent IAB node indicating a timing scheme to be applied to the IAB-MT and to transmit a signal to the parent IAB node in a backhaul uplink; and an IAB-DU configured to transmit a signal to the sub-IAB node in the backhaul downlink, wherein, in the case where the indicated timing scheme is a first timing scheme in which a transmission timing of the IAB MT coincides with a transmission timing of the IAB DU, a transmission timing at which the IAB-MT transmits the signal and a transmission timing at which the IAB-DU transmits the signal are set identically.

According to another aspect of the present disclosure, there is provided an IAB node for transmitting a signal via a backhaul link between a parent IAB node and a child IAB node in a wireless communication system. The IAB node comprises: at least one transceiver; and a controller coupled to the at least one transceiver, the controller configured to: signaling information indicating a timing scheme to be applied is received from a parent IAB node, and in the case where the indicated timing scheme is a first timing scheme in which a transmission timing of an IAB MT of the IAB node coincides with a transmission timing of an IAB DU of the IAB node, a signal is transmitted to the parent IAB node in a backhaul uplink and a signal is transmitted to a child IAB node in a backhaul downlink, wherein the transmission timing at which the IAB-MT transmission signal is located and the transmission timing at which the IAB-DU transmission signal is located are set identically.

According to another aspect of the present disclosure, there is provided a method for receiving a signal by a parent IAB node via a backhaul link between the parent IAB node and an IAB node in a wireless communication system. The method comprises the following steps: transmitting signaling information indicating a timing scheme to be applied to an IAB node to the IAB node including the IAB-MT and the IAB-DU; and receiving a signal from the IAB-MT via the backhaul link in a case where the indicated timing scheme is a first timing scheme in which a transmission timing of the IAB-MT coincides with a transmission timing of the IAB-DU, wherein the transmission timings of the IAB-MT and the IAB-DU are identically set based on the signaling information.

In accordance with another aspect of the present disclosure, a parent Integrated Access and Backhaul (IAB) node is provided for receiving a signal via a backhaul link between the parent IAB node and the IAB node in a wireless communication system. The parent IAB node includes: at least one transceiver, and a controller coupled to the at least one transceiver, the controller configured to: transmitting signaling information indicating a timing scheme to be applied to the IAB node from the IAB node including the IAB-MT and the IAB-DU; and receiving a signal from the IAB-MT via the backhaul link in a case where the indicated timing scheme is a first timing scheme in which the transmission timing of the IAB-MT coincides with the transmission timing of the IAB-DU, wherein the transmission timings of the IAB-MT and the IAB-DU are set identically based on the signaling information.

Other aspects, advantages, and salient features of the disclosure will become apparent to those skilled in the art from the following detailed description, which, taken in conjunction with the annexed drawings, discloses various embodiments of the disclosure.

Drawings

The above and other aspects, features, and advantages of certain embodiments of the present disclosure will become more apparent when the following detailed description is considered in conjunction with the accompanying drawings in which:

fig. 1 is a schematic diagram illustrating a wireless communication system in which an Integrated Access and Backhaul (IAB) node operates in accordance with an embodiment of the present disclosure;

fig. 2A and 2B are diagrams illustrating Time Division Multiplexing (TDM) and Frequency Division Multiplexing (FDM) between access links and backhaul links of an IAB node, respectively, according to various embodiments of the present disclosure;

fig. 3A and 3B are diagrams illustrating TDM between access links and backhaul links of an IAB node according to various embodiments of the present disclosure;

fig. 4A and 4B are diagrams illustrating FDM and Space Division Multiplexing (SDM) between access links and backhaul links of an IAB node according to various embodiments of the present disclosure;

fig. 5 is a diagram illustrating a structure of an IAB node according to an embodiment of the present disclosure;

fig. 6 is a diagram illustrating a communication method for simultaneous transmission and reception of a Mobile Terminal (MT) and a Distributed Unit (DU) included in an IAB node in a wireless communication system according to an embodiment of the present disclosure;

Fig. 7 is a diagram illustrating a communication method for aligning backhaul link transmission timing among IAB nodes in a wireless communication system according to an embodiment of the present disclosure;

fig. 8 illustrates a flowchart of the operation of a next generation Node B (gNB)/parent IAB Node in a wireless communication system according to an embodiment of the disclosure;

fig. 9 is a flowchart illustrating an operation of an IAB node in a wireless communication system according to an embodiment of the present disclosure;

fig. 10 is a block diagram showing a configuration of a User Equipment (UE) according to an embodiment of the present disclosure;

fig. 11 is a block diagram showing a configuration of a gNB according to an embodiment of the disclosure; and is also provided with

Fig. 12 is a block diagram showing a configuration of an IAB node according to an embodiment of the present disclosure.

Like reference numerals are used throughout the drawings to denote like elements.

Detailed Description

The following description is provided with reference to the accompanying drawings in order to assist in a comprehensive understanding of the various embodiments of the disclosure as defined by the claims and their equivalents. It includes various specific details to aid in understanding, but these specific details should be considered exemplary only. Accordingly, one of ordinary skill in the art will recognize that various changes and modifications of the various embodiments described herein can be made without departing from the scope and spirit of the present disclosure. In addition, descriptions of well-known functions and constructions may be omitted for clarity and conciseness.

The terms and words used in the following description and claims are not limited to literal meanings, but are used only by the inventors to enable a person to clearly and consistently understand the present disclosure. Accordingly, it will be apparent to those skilled in the art that the following descriptions of the various embodiments of the present disclosure are provided for illustration only and not for the purpose of limiting the disclosure as defined by the appended claims and their equivalents.

It should be understood that the singular forms "a", "an" and "the" include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to a "component surface" includes reference to one or more such surfaces.

In describing embodiments of the present disclosure, techniques that are well known in the art to which the present disclosure pertains and that are not directly related to the present disclosure will not be described. This is intended to clearly convey the subject matter of the present disclosure without making any ambiguity by avoiding unnecessary descriptions.

For the same reason, some components shown in the drawings are exaggerated, omitted, or schematically shown, and the drawn size of each component does not exactly reflect its actual size. In each drawing, the same reference numerals are assigned to the same or corresponding parts.

Advantages and features of the present disclosure and methods of accomplishing the same may become apparent by reference to the embodiments described in detail below in conjunction with the accompanying drawings. However, the present disclosure may be implemented in various ways not limited to the embodiments set forth herein. Rather, by providing such embodiments, the present disclosure is thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art, and the present disclosure is defined only by the appended claims. Like reference numerals refer to like elements throughout the specification.

It will be understood that each block of the flowchart illustrations and/or block diagrams, and any combination of blocks in the flowchart illustrations and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be loaded onto a processor of a general purpose computer, special purpose computer, or other programmable data processing apparatus to produce a machine, such that the instructions which execute via the processor of the computer or other programmable data processing apparatus create means for implementing the functions/acts specified in the flowchart and/or block diagram block or blocks. These computer program instructions may also be stored in a computer usable or computer-readable memory that can 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 function/act specified in the flowchart and/or block diagram block or blocks. The computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operations to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions/acts specified in the flowchart and/or block diagram block or blocks.

Further, the respective block diagrams may illustrate portions of modules, segments, or code that include one or more executable instructions for performing specific logic functions. Further, it should be noted that the functions of the respective blocks may be performed in a different order among several modifications. For example, two consecutive blocks may be performed in sequence, simultaneously, or in reverse order according to their functions.

As used herein, the term "unit" means, but is not limited to, a software or hardware component, such as a Field Programmable Gate Array (FPGA) or an application-specific integrated circuit (ASIC), that performs certain tasks. The units may advantageously be configured to reside on the addressable storage medium and configured to execute on one or more processors. Thus, by way of example, a unit may include components, such as software components, object-oriented software components, class components and task components, procedures, functions, properties, programs, subroutines, segments of degree code, drivers, firmware, microcode, circuitry, data, databases, data structures, tables, arrays, and variables. The functionality provided for in the components and "units" may be combined into fewer components and "units" or further separated into additional components and "units. Furthermore, the components and "units" may be implemented to execute on one or more Central Processing Units (CPUs) or secure multimedia cards in a device.

Wireless communication systems have been developed that go beyond the original voice-centric services to provide high-speed high-quality packet data services, such as various communication standards including, for example, high-speed packet access (HSPA) of the third generation partnership project (3 GPP), long Term Evolution (LTE) (or evolved universal terrestrial radio access (E-UTRA)), high-speed packet data (HRPD) of LTE-advanced (LTE-a) and LTE-Pro, and 3GPP2, ultra Mobile Broadband (UMB), and Institute of Electrical and Electronics Engineers (IEEE) 802.16E.

LTE systems, which are a major example of broadband wireless communication systems, take the form of Orthogonal Frequency Division Multiplexing (OFDM) for the downlink and single carrier frequency division multiple access (SC-FDMA) for the Uplink (UL). UL refers to a radio link over which User Equipment (UE) (terminal or Mobile Station (MS)) transmits data or control signals to next generation node B (or eNode B or Base Station (BS)), and DL refers to a radio link over which base station transmits data or control signals to UE. In the multiple access scheme, data or control information of different users are distinguished from each other by allocating and managing non-overlapping time-frequency resources (i.e., having orthogonality therebetween) for transmission of the data or control information of the different users.

Since the LTE-advanced communication system, i.e., the fifth generation (5G) (or new air interface (NR)) system should freely reflect various requirements from users and service providers, services satisfying the various requirements should be simultaneously supported. Services considered for 5G communication systems include enhanced mobile broadband (EMBB), large-scale machine-type communication (mctc), and ultra-reliable low latency communication (URLLC).

The goal of the eMBB is to provide a much higher data rate than supported by conventional LTE, LTE-A or LTE-Pro. For example, a 5G communication system should be able to provide data rates of up to 20Gbps on DL and up to 10Gbps on UL from the perspective of a single gNB. In addition to the maximum data rate, the 5G communication system should also provide an increased user perceived data rate. To meet these requirements, advances in various transmission and reception techniques including Multiple Input Multiple Output (MIMO) are needed. Although signals are transmitted at a transmission bandwidth of up to 20MHz at 2GHz in the current LTE, a frequency bandwidth wider than 20MHz is used at or above 3 to 6GHz in the 5G communication system, thereby satisfying a data rate required in the 5G communication system.

Furthermore, mctc is considered to support application services in 5G communication systems, such as internet of things (IoT). To achieve efficient IoT, mctc requires support: access from a large number of UEs within a cell, improved coverage of UEs, extended battery life, and reduced cost of UEs. IoT devices perform communication functions by attaching to various sensors and devices, and should be able to support a huge number of UEs (e.g., 1,000,000UEs/km ² ). Furthermore, mctc-enabled UEs require wider coverage than in other services in view of the nature of the service, since there is a high likelihood that they are placed in shadow areas not covered by cells, such as the basement of a building. Mctc-enabled UEs should be low cost and have very long battery lives, such as 10 to 15 years, because their batteries are difficult to replace frequently.

Finally, URLLC is a mission critical, cellular-based wireless communication service. Such as URLLC may be considered a service for remote control of robots or machines, industrial information, unmanned aerial vehicles, remote healthcare, and emergency alerts. Accordingly, URLLC should provide communication with very low latency and very high reliability. For example, a service supporting URLLC should meet an air interface latency of less than 0.5 ms and have a latency of 10 ^-5 Or lower packet error rate requirements. Thus, for services supporting URLLC, the 5G system should be designed to provide smaller Transmission Time Intervals (TTIs) than other services and allocate wide band resources to ensure reliability of the communication link.

Three services of the 5G system, namely emmbb, URLLC, and mctc, can be multiplexed in a single system. To meet the different requirements of these services, different transmission and reception techniques and different transmission and reception parameters may be used for these services.

In 5G systems, coverage may be limited by propagation path attenuation when the gNB transmits or receives data to or from the UE in a frequency band above 6GHz, particularly in the millimeter wave (mmWave) frequency band, and in the 3 to 6GHz frequency band. Although the problem caused by limited coverage can be solved by densely deploying a plurality of relays (or relay nodes) in the propagation path between the gNB and the UE, it becomes a troublesome problem to generate a very high cost in installing an optical cable for backhaul connection between the relays. Accordingly, using broadband radio resources available in mmWave without installing fiber optic cables between relays may result in elimination of the cost problem of installing fiber optic cables and more efficient use of mmWave bands.

As described above, a technique of transmitting and receiving backhaul data to and from the gNB through at least one relay node in mmWave and 3 to 6GHz bands and finally transmitting and receiving data as access data to and from the UE is called Integrated Access and Backhaul (IAB). A relay node that transmits and receives data to and from the gNB over a wireless backhaul is referred to as an IAB node. The gNB (or BS, also known as IAB host) includes a Central Unit (CU) and a Distributed Unit (DU), and the IAB node includes a DU and a Mobile Terminal (MT). A CU manages DUs of all IAB nodes connected to the gNB through multi-hops.

The IAB node uses different frequency bands or the same frequency band when receiving backhaul data from the gNB and transmitting access data to the UE and when receiving access data from the UE and transmitting backhaul data to the BS. When the same frequency band is used, the IAB node has unidirectional transmission/reception characteristics (half duplex limitation) at one time. Accordingly, in order to reduce transmission/reception delay caused by unidirectional transmission/reception characteristics of the IAB node, the IAB node may multiplex backhaul data (e.g., assuming that a parent IAB node, an IAB node as a relay node, and a child IAB node are connected through a radio backhaul link, DL data of a DU from the parent IAB node to an MT of the IAB node and UL data of a DU from the child IAB node MT to the IAB node) and access data from a UE (UL data from the UE to the IAB node) (e.g., in Frequency Division Multiplexing (FDM) and/or Space Division Multiplexing (SDM)). The relationship between the parent node and the IAB node and the relationship between the child node and the IAB node may be referred to 3gpp TS 38.300 section 4.7 integrated access and backhaul. During transmission, the IAB node may also multiplex backhaul data (UL data from the MT of the IAB node to the DU of the parent IAB node and DL data from the DU of the IAB node to the MT of the child IAB node) and access data to the UE (DL data from the IAB node to the UE) (in FDM and/or SDM).

When a DU of a parent IAB node receives a signal from an MT of an IAB node, transmission of the DU from the IAB node to the MT of a child IAB node may interfere with signal reception at the DU of the parent IAB node. Further, when the MT of the child IAB node receives a signal from the DU of the IAB node, transmission of the DU from the MT of the IAB node to the parent IAB node may interfere with signal reception at the MT of the child IAB node.

In order to eliminate interference during simultaneous transmissions of MTs and DUs from an IAB node, a method of aligning slot timing between simultaneous transmissions of DUs and MTs from an IAB node is applied in the present disclosure such that interference to reception at a DU of a parent IAB may be uniform across all symbols of a DU slot. Furthermore, the interference to reception at the MT to the sub-IAB node may be uniform across all symbols of the MT slot. In this case, since the influence of interference on the entire DU slot or MT slot is the same, the signal in the slot can be recovered by estimating the interference in a specific symbol of the DU slot of the parent IAB or MT slot of the child IAB node and canceling the estimated interference in all symbols of the DU slot of the IAB node or MT slot of the child IAB node. Accordingly, the present disclosure proposes a method of applying the same transmission timing according to the unidirectional transmission/reception characteristics in the case of simultaneous transmission as described above, and related operations of the IAB node.

Fig. 1 is a schematic diagram illustrating a wireless communication system in which an IAB node operates according to an embodiment of the present disclosure.

Referring to fig. 1, a gNB is a typical BS (e.g., eNB or gNB) and may also be referred to as an eNB, BS, hosting gNB, or hosting IAB in this disclosure. The first IAB node (IAB node # 1) 111 and the second IAB node (IAB node # 2) 121 are IAB nodes that transmit and receive signals on the backhaul link 114 in the mmWave frequency band and the 3 to 6GHz frequency band. The first UE (UE 1 1) 102 sends and receives access data to and from the gNB 101 over the access link 103. The IAB node #1 111 transmits and receives backhaul data to and from the gNB 101 on the backhaul link 104. The second UE (UE 2) 112 sends and receives access data to and from the IAB node #1 111 on the access link 113. The IAB node #2 121 transmits and receives backhaul data to and from the IAB node #1 111 on the backhaul link 114. Accordingly, IAB#1 111 is a parent IAB, also referred to as IAB#2 121, and IAB#2 121 is a child IAB, also referred to as IAB#1 111, of a lower IAB. The third UE (UE 3) 122 sends and receives access data to and from the IAB node #2 121 on the access link 123. In fig. 1, backhaul links 104 and 114 may be radio backhaul links.

Now, measurements made at the UE on the IAB node or the home gNB will be described.

In order for UE 2 112 or UE 3 122 to be able to perform measurements on neighboring home gnbs or IAB nodes instead of serving IAB nodes, cooperation between the home gnbs and the IAB nodes may be required. That is, the home gNB may match measurement resources between IAB nodes with even-numbered hop-ordering (even-numbered hop orders) or with odd-numbered hop-ordering, thereby enabling the UE to perform measurements on neighboring IAB nodes or gnbs with minimal resource consumption. The UE may receive configuration information from the serving IAB node or the gNB through higher layer signaling (higher layer signal) indicating that the UE measures a Synchronization Signal Block (SSB)/Physical Broadcast Channel (PBCH) or a channel state information reference signal (CSI-RS) for measurement of the neighbor IAB. When a UE is configured to measure neighbor gnbs through SSB/PBCH (may also be referred to as "SS/PBCH" or "SSB"), the UE may be configured with two SS/PBCH measurement timing configurations per frequency (SMTC) for measurement resources for an IAB node with even-numbered hopping ordering or an IAB node with odd-numbered hopping ordering. Upon receiving the configuration information, the UE may measure the IABs with even-numbered hop-ordering with one SMTC and measure the IAB nodes with odd-numbered hop-ordering with another SMTC.

Measurements of another IAB node at an IAB node or a home gNB will be described below.

In order for the IAB node to be able to perform measurements on the neighboring hosting gNB or IAB node, cooperation between the hosting gNB and the IAB node may be required. That is, the home gNB may match measurement resources between IAB nodes with even-numbered hop-ordering or with odd-numbered hop-ordering, thereby enabling an IAB node to perform measurements on neighboring IAB nodes or IAB gnbs with minimal resource consumption. The IAB node may receive configuration information from a serving IAB node or a gNB through higher layer signaling, which information indicates that the IAB node measures SS/PBCH or CSI-RS for measurement of neighboring IAB nodes. When an IAB node is configured to measure neighbor gnbs through SSB/PBCH, the UE may be configured with two SMTCs per frequency for measurement resources for an IAB with even-numbered hop-ordering or an IAB node with odd-numbered hop-ordering. Upon receiving the configuration information, the IAB node may measure the IAB with an even-numbered hop-ordering with one SMTC and measure the IAB with an odd-numbered hop-ordering with another SMTC.

Multiplexing of access links between a gNB and an IAB node or between an IAB node and a gNB and a UE or between an IAB node and a UE in radio resources according to the IAB technology proposed in the present disclosure will be described in detail below with reference to FIGS. 2A, 2B, 3A, 3B, 4A and 4B.

Fig. 2A and 2B are diagrams illustrating examples of resource multiplexing between access links and backhaul links in an IAB node according to various embodiments of the disclosure.

Fig. 2A is a diagram illustrating an example of resource Time Division Multiplexing (TDM) between an access link and a backhaul link in an IAB node. Fig. 2B is a diagram illustrating an example of resource Frequency Division Multiplexing (FDM) between an access link and a backhaul link in an IAB node.

Referring to fig. 2A, in radio resources 201, a backhaul link 203 between a gNB and an IAB node or between an IAB node and an access link 202 between a gNB and a UE or between an IAB node and a UE are multiplexed in TDM. Accordingly, when resources are multiplexed between an access link and a backhaul link in an IAB node in TDM as shown in fig. 2A, data is not transmitted and received between the gbb and the IAB node in a time region where the gbb or the IAB node transmits and receives data to and from the UE, and the gbb or the IAB node does not transmit and receive data to and from the UE in a time region where data is transmitted and received between the gbb and the IAB node.

Referring to fig. 2B, in radio resources 211, backhaul links 213 between the gNB and the IAB nodes or between the IAB nodes and access links 212 between the gNB and the UE or between the IAB nodes and the UE are multiplexed with FDM. Therefore, although data can be transmitted and received between the gNB and the IAB in a time zone in which the gNB or the IAB node transmits and receives data to and from the UE, only data transmission in the same direction is possible due to the unidirectional transmission/reception characteristics of the IAB node. For example, in a time region where the first IAB node receives data from the UE, the first IAB node may receive only backhaul data from another IAB node or the gNB. Further, in a time region where the first IAB node transmits data to the UE, the first IAB node may transmit backhaul data only to another IAB node or the gNB.

Although only TDM and FDM are described as multiplexing schemes in the examples of fig. 2A and 2B, space Division Multiplexing (SDM) between the access link and the backhaul link is also available. Thus, although transmission/reception can be performed with SDM on the access link and the backhaul link, only data transmission in the same direction is possible in view of unidirectional transmission/reception characteristics of the IAB node, as in FDM shown in fig. 2B. For example, in a time region where the first IAB node receives data from the UE, the first IAB node may receive only backhaul data from another IAB node or the gNB. Further, in a time region where the first IAB node transmits data to the UE, the first IAB node may transmit backhaul data only to another IAB node or the gNB.

When an IAB node initially accesses a gNB or a higher IAB node, the IAB node may transmit information indicating which of TDM, FDM, and SDM is used to the gNB or the higher IAB node (e.g., a parent IAB node) in capability information on the multiplexing scheme. Alternatively, the IAB node may later receive information from the gNB or higher IAB node indicating which of TDM, FDM, and SDM to use, through higher layer signaling (higher layer signals), such as system information or Radio Resource Control (RRC) information. Alternatively, after initial access, the IAB node may receive information on the backhaul link from the gNB or higher layer IAB node indicating which of TDM, FDM, and SDM to use. Alternatively, after the capability information is sent to the gNB or higher IAB node, the determination as to which multiplexing scheme to use may depend on the implementation of the IAB, and the IAB node may report the multiplexing scheme to be used in a particular time slot or radio frame to the gNB or higher IAB node over a particular time period or continuously over backhaul or higher layer signaling.

Although the multiplexing scheme between the access link and the backhaul link has been mainly described in the examples of fig. 2A and 2B, the same multiplexing scheme may be applied between the backhaul links. For example, MT (backhaul link) and DU (backhaul link or access link) of one IAB node may be multiplexed by the methods described in the examples of fig. 2A and 2B, as described below.

Fig. 3A and 3B are diagrams illustrating TDM between an access link and a backhaul link in resources in an IAB node according to various embodiments of the present disclosure; .

Fig. 3A illustrates a process by which an IAB node 302 communicates with a parent node 301, a child IAB node 303, and a UE 304. The links between nodes will be described in more detail. Parent node 301 is in backhaul downlink L _P,DL 311 to the IAB node 302, and the IAB node 302 is on the backhaul UL L _P,UL A backhaul UL signal is sent on 312 to parent node 301. IAB node 302 accessing DL L _A,DL 316 sends an access DL signal to the UE 304 and the UE 304 is accessing UL L _A,UL An access UL signal is sent 315 to the IAB node 302. IAB node 302 on backhaul DL L _C,DL 313 to transmit backhaul DL signals to the sub-IAB node 303 and the sub-IAB node 303 is on backhaul UL L _C,UL A backhaul UL signal is sent on 314 to the IAB node 302. In the examples of fig. 3A and 3B, the subscript P refers to the backhaul link with the parent, the subscript a refers to the access link with the UE, and the subscript C refers to the backhaul link with the child.

The link relationships of fig. 3A have been described from the perspective of the IAB node 302. From the perspective of the child IAB node 303, the parent node is IAB node 302, and there may be another lower child IAB node for the child IAB node 303. From the perspective of parent node 301, the child node is an IAB node 302, and there may be another IAB parent node above parent node 301.

Each of the backhaul UL/DL signal and the access UL/DL signal may include at least one of data and control information, a channel carrying the data and control information, a Reference Signal (RS) required for data and control information decoding, or an RS required for obtaining channel information.

Fig. 3B shows an example of multiplexing all of the above links in TDM. In the example of fig. 3B, backhaul DL L _P,DL 311. Backhaul DL L _C,DL 313. Accessing DL L _A,DL 316. Accessing UL L _A,UL 315. Backhaul UL L _C,UL 314 and backhaul UL L _P,UL 312 are multiplexed in time order. The precedence relationships of links in the examples of fig. 3A and 3B are examples only, and any other precedence relationships may be applied.

Since these links are multiplexed in time order in TDM, this is the most time-consuming multiplexing scheme to send signals from parent 301 through IAB node 302 to child IAB node 303 and to UE 304. Thus, to reduce the delay in the final transmission of signals from parent node 301 into UE 304, a method of multiplexing with FDM or SDM between backhaul links or between backhaul links and access links for simultaneous transmission may be considered.

Fig. 4A and 4B are diagrams illustrating examples of FDM and SDM between access links and backhaul links in an IAB node according to various embodiments of the disclosure.

With reference to fig. 4A and 4B, a method of reducing latency by multiplexing between backhaul links or between backhaul links and access links with FDM or SDM will be described.

Similar to fig. 3A, fig. 4A illustrates a process in which an IAB node 402 communicates with a parent node 401, a child IAB node 403, and a UE 404. The links between nodes will be described in more detail. Parent node 401 is in backhaul DL L _P,DL 411 sends a backhaul DL signal to the IAB node 402 and the IAB node 402 is on a backhaul UL L _P,UL 412 transmit a backhaul UL signal to parent node 401. IAB node 402 is accessing DL L _A,DL 416 sends an access DL signal to the UE 404, and the UE 404 is accessing UL L _A,UL An access UL signal is sent 415 to the IAB node 402. IAB node 402 on backhaul DL L _C,DL 413 to transmit backhaul DL signal to the sub-IAB node 403, and the sub-IAB node403 on backhaul UL L _C,UL A backhaul UL signal is sent on 414 to the IAB node 402. In the examples of fig. 4A and 4B, the subscript P refers to the backhaul link with the parent, the subscript a refers to the access link with the UE, and the subscript C refers to the backhaul link with the child.

The link relationship of fig. 4A is depicted from the perspective of the IAB node 402. From the perspective of the child IAB node 403, the parent node is the IAB node 402, and there may be another child IAB node below the child IAB node 403. From the perspective of parent node 401, the child node is an IAB node 402, and there may be another IAB parent node above parent node 401.

Each of the backhaul UL/DL signal and the access UL/DL signal may include at least one of data and control information, a channel carrying the data and control information, an RS required for data and control information decoding, or an RS required for obtaining channel information.

Fig. 4B shows FDM or SDM.

As described above, the IAB node has unidirectional transmission/reception characteristics at one time, and thus signals that can be multiplexed in FDM or SDM are limited. For example, considering the unidirectional transmission/reception characteristics of the IAB node 402, the backhaul UL L may be multiplexed in the time region available for transmission from the IAB node 402 _P,UL 412. Backhaul DL L _C,DL 413 and access DL L _A,DL 416. Accordingly, when links are multiplexed in FDM or SDM, the IAB node 402 may transmit signals on all links in the same time region, as indicated by reference numeral 421. Furthermore, backhaul DL L can be multiplexed in a time region available for reception at the IAB node 402 _P,DL 411. Backhaul UL L _C,UL 414 and access UL L _A,UL 415. Accordingly, when links are multiplexed in FDM or SDM, the IAB node 402 may receive signals on all links in the same time region.

The link multiplexing in the embodiments of fig. 4A and 4B is only an example, and it is apparent that only two of the three links may be multiplexed with FDM or SDM. That is, the IAB node may transmit/receive signals by multiplexing some of the links available for multiplexing.

Now, the structure of the IAB node will be described.

Various types of gNB structures optimized for service requirements have been studied to support various services in 5G systems, such as high capacity transmission, low latency high reliability transmission, or large scale MTC, and to reduce capital expenditure (CAPEX). In 4G LTE, a cloud RAN (C-RAN) architecture has been commercialized, in which the radio processor and the radio transceiver (or Remote Radio Head (RRH)) of the BS are separated and the radio processor is centralized, while the radio transceiver exists at a cell site, thereby reducing CAPEX and efficiently controlling interference. In the C-RAN architecture, a Common Public Radio Interface (CPRI) optical link is typically used when the radio processor of the BS transmits baseband digital in-phase and quadrature-phase (IQ) data to the radio transceiver. A large data capacity is required when transmitting data to the radio transceiver. For example, 614.4Mbps is required for 10MHz Internet Protocol (IP), and 1.2Gbps is required for 20MHz IP data. Thus, the 5G RAN structure is designed such that the gNB is divided into CUs and DUs to reduce the huge load of the optical link, and functional split is applied to CUs and DUs to have various structures. The 3GPP is working on various function split options between CUs and DUs, and these function split options perform function splitting between protocol layers or within protocol layers. There are a total of 8 options, namely option 1 through option 8. Wherein option 2 and option 7 are considered to have priority in the current 5G gNB structure. In option 2, the RRC layer and Packet Data Convergence Protocol (PDCP) layer are located in the CU, and the Radio Link Control (RLC) layer, medium Access Control (MAC) layer, physical (PHY) layer, and Radio Frequency (RF) layer are located in the DUs. In option 7, the RRC layer, PDCP layer, RLC layer, MAC layer, and higher PHY layer are located in the CU, and the lower PHY layer is located in the DU. A structure for splitting and moving NR network protocols with deployment flexibility can be implemented between CUs and DUs through the above functional splitting. The flexible hardware implementation based on this architecture provides a cost-effective solution, the CU-DU splitting architecture enables load management, implementation of performance optimized tuning, and Network Function Virtualization (NFV)/Software Defined Network (SDN), and the configurable function splitting is applicable to various application examples (variable latency in transmission).

Accordingly, the structure of the IAB node considering the above-described function splitting will be described with reference to fig. 5.

Fig. 5 is a diagram schematically illustrating a structure of an IAB node according to an embodiment of the present disclosure.

Referring to fig. 5, the gNB 501 includes CUs and DUs, and each of the IAB nodes has a UE function (MT) for transmitting and receiving data to and from a parent node over a backhaul link and a gNB function (DU) for transmitting and receiving data to and from a child node over the backhaul link. In fig. 5, the IAB node #1 502 is wirelessly connected to the gNB 501 by one hop, and the IAB node #2 503 is wirelessly connected to the gNB 501 by two hops via the IAB node #1 502.

Referring to fig. 5, a CU of the gNB 501 may control DUs of all IAB nodes (i.e., IAB node #1 and IAB node # 2) wirelessly connected to the gNB 501 and DUs of the gNB 501, as indicated by reference numerals 511 and 512. The CUs of the gNB 501 may allocate radio resources to these DUs so that they transmit/receive data to/from MTs of the IAB nodes below these DUs. The radio resource allocation may be sent to the DU via an F1 application protocol (F1 AP) interface by a higher layer signal (e.g., system information or RRC information or physical layer signal). For F1AP, reference may be made to 3gpp TS 38.473. The radio resources may include DL time resources, UL time resources, flexible time resources, and the like.

The radio resource configuration will be described in detail in the context of IAB node #2 503. The DL time resource is a resource in which the DU of the IAB node #2 503 transmits a DL control/data signal to the MT of the lower IAB node. The UL time resource is a resource in which the DU of the IAB node #2 503 receives UL control/data signals from the MT of the lower IAB node. The flexible time resource is a resource that can be used as a DL time resource or an UL time resource by the DU, and how to use the flexible time resource can be indicated to the MT of the lower IAB node through a DL control signal from the DU. Upon receiving the DL control signal, the MT of the lower IAB node may determine whether to use the flexible time resource as a DL time resource or a UL time resource. When the MT of the lower IAB node fails to receive the DL control signal, the MT of the lower IAB node does not perform a transmission/reception operation. That is, the MT does not monitor or decode DL control channels in the resources or does not measure signals in the resources. The MT of the lower IAB node does not perform a transmission/reception operation in the resource. For DL time resources, UL time resources, and flexible time resources, a CU may indicate to a DU two different types (or three different types including always unavailable time resources).

The first type is a soft type. The CUs of the gNB 501 may configure soft-type DL time resources, UL time resources, and flexible time resources to the DUs of the IAB node #2 503 through the F1AP (interface between the CUs and DUs). The IAB node #1 502 of the parent IAB (or the DU of the parent IAB) as the IAB node #2 503 may explicitly (e.g., via a Downlink Control Information (DCI) format) or implicitly indicate whether the configured soft-type resource is available or not available to the IAB node #2 503 as the child IAB node (or the DU of the child IAB node). That is, when a specific resource is indicated as available, the DU of the IAB node #2 503 may use the resource for transmitting/receiving data to/from the MT of the lower IAB node. That is, when the resource is a DL resource, the DU of the IAB node #2 503 may perform transmission, and when the resource is a UL resource, the DU of the IAB node #2 503 may perform reception. When the resource is indicated as unavailable, the IAB node #2 503 may transmit/receive data to/from the MT of the lower IAB node without using the resource. That is, the DU of the AB node #2 503 does not transmit or receive signals in the resources.

The method of indicating the availability of soft-type resources through the DCI format will be described in more detail. The DCI format in this embodiment may include an availability indicator to indicate the availability of one or more consecutive UL symbols, DL symbols, or flexible symbols.

For receiving the DCI format, the IAB node #2 503 may initially receive information about the position of an availability indicator (indicating availability for the IAB node # 2) in the DCI format, a table indicating availability of time resources corresponding to a plurality of slots, or a mapping relation of the availability indicator together with a cell Identifier (ID) of the IAB node #2 503 from a CU or a parent IAB node through a higher layer signal. The values (or indications) indicating the availability of consecutive UL symbols, DL symbols or flexible symbols in one slot and the meaning of these values (or indications) may be configured as illustrated in table 1 below.

TABLE 1

Upon the IAB node #2 503 receiving the above-described indication of the availability indicator in the DCI format from the parent IAB node, the DU of the IAB node #2 503 may explain the relationship between DL time resources, UL time resources, or flexible time resources configured by the CU for the IAB DU and the above-described availability by the following method.

The first method is that the number of values indicating availability contained in the availability indicator of the intended DCI format of the IAB DU is equal to the number of soft-type slots configured by the CU, including consecutive symbols. According to this method, the IAB DU can determine that the availability is only applicable to slots comprising a soft type.

The second method is that the number of values indicating availability contained in the availability indicator of the intended DCI format of the IAB DU is equal to the number of all slots configured by the CU, i.e. all slots including the hard/soft/unavailable (NA) type. In this embodiment, the IAB DU may determine that the availability is applicable only to timeslots including a soft type and the indicated availability is not applicable to timeslots including only a hard type or a NA type and not including a soft type.

In the first and second methods, the IAB DU may expect the meaning of the value indicating availability to match DL resources, UL resources or flexible resources configured by the CU. For example, when there are only DL soft resources or DL hard resources in a slot, the IAB DU may expect that only a value of 1 in table 1 may be indicated. Thus, the IAB node may expect that among the various values of table 1, a value including the availability of UL soft resources is not indicated.

Further, the IAB DU may determine, at least for flexible resources configured by the CU, whether the flexible resources are used as DL resources or UL resources in addition to a value indicating that the flexible resources are available. For example, with respect to flexible soft resources or flexible hard resources, the IAB node may expect that the indicated value may be 1 or 2 in table 1 instead of the value 4. In this case, the DU of the IAB node #2 may determine that the flexible resource may be used only for UL or DL by an indication from the parent IAB node instead of according to the determination result of the IAB node # 2.

Furthermore, the IAB DU contemplates that the value 0 in table 1 may be indicated for any hard/soft or NA resources configured by the CU. In this case, the IAB DU determines that hard/soft resources configured by the CU are not available, and until the resources are indicated by the DCI format later, these resources are not available for transmitting and receiving data to and from the MT of the lower IAB node by the DU of the IAB node #2, just as the always unavailable resource types configured by the CU. Thereafter, when the DCI format indicates that these resources are available again, the DU of IAB node #2 may use these resources as configured by the CU and indicated by the DCI format.

The second type is a hard type in which the above-described resources are always used between the DU and the MT. That is, when the resource is a DL time resource, the DU of the IAB node #2 may perform transmission, and when the resource is a UL resource, the DU of the IAB node #2 may perform reception regardless of transmission and reception of the MT of the IAB node # 2. When the resource is a flexible resource, the IAB DU may perform transmission or reception according to a determination result of the IAB DU, that is, according to a DCI format indicating whether the flexible resource is a DL resource or a UL resource to an MT of a lower IAB node.

The third type is a type that is not available at any time (not used at all or not always available), and the DU of the IAB node #2 can transmit/receive data to/from the MT without using these resources.

In the above type, the DU may also receive information about the above type when signaling DL time resources, UL time resources, flexible time resources, and reserved time resources through higher layer signals from the CU.

Referring to fig. 5, the DU of the gNB 501 performs a normal gNB operation and performs scheduling to control the MT of the IAB node #1 to transmit and receive data (521). The DU of the IAB node #1 502 performs a normal gNB operation and performs scheduling, thereby controlling the MT of the IAB node #2 503 to transmit/receive data (522).

The DU may indicate radio resources to transmit/receive data to/from the MT of the IAB node to the MT of the lower IAB node based on radio resources configured by the CU. The configuration of radio resources may be transmitted to the MT through system information, higher layer signals, or physical layer signals. The radio resources may include DL time resources, UL time resources, flexible time resources, etc., and reserved time resources. The DL time resource is a resource in which a DU transmits a DL control/data signal to an MT of a lower IAB node. The UL time resource is a resource in which a DU receives UL control/data signals from an MT of a lower IAB node. The flexible time resource is a resource that can be used as a DL time resource or UL time resource of the DU, and how to use the flexible time resource for the MT of the lower IAB node can be indicated by a DL control signal from the DU. Upon receiving the DL control signal, the MT may determine whether to use the flexible time resource as a DL time resource or a UL time resource. Upon failure to receive the DL control signal, the MT does not perform a transmission/reception operation. That is, the MT does not monitor or decode DL control channels in the resources or does not measure signals in the resources.

The DL control signal may be signaled to the MT in the form of a combination of higher layer signals and physical layer signals, and the MT may receive signaling to determine a slot format in a particular slot. The slot format may be configured to begin substantially with DL symbols, include flexible symbols in the middle, and end with UL symbols (e.g., in a D-F-U structure). When only the above slot format is used, the DU of the IAB node may perform DL transmission at the beginning of the slot. However, since the MT of the IAB node is configured with the same slot format (i.e., D-F-U structure) by the parent IAB node, the MT of the IAB node may not perform UL transmission at the same time (corresponding to slot format indexes 0 to 55 in table 2 below). As an example, slot formats configured to start with UL symbols, include flexible symbols in the middle, and end with DL symbols (corresponding to slot format indexes 56 to 96 in table 2 below) are illustrated in table 2 below. The slot format illustrated in table 2 below may be transmitted to the MT through a DL control signal, and the slot format may be configured for DUs by a CU using the F1 AP.

TABLE 2

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The reserved time resources are resources in which data can not be transmitted/received to/from a lower MT of the DU, and the MT does not perform a transmission/reception operation in these resources. That is, the MT does not monitor or decode DL control channels in the resources or does not measure signals in the resources.

Accordingly, the MT of one IAB node receives scheduling and transmits/receives data under the control of the DU of the higher IAB node, and the DU of the IAB node is controlled by the CU of the gNB 501. Since the MT and the DU of one IAB are controlled by different entities, it is difficult to coordinate the MT and the DU in real time.

All possible simultaneous transmission and reception scenarios between the MT and DU of the IAB node will be described below.

Fig. 6 is a diagram illustrating a communication method for simultaneous transmission and reception between an MT and a DU of an IAB node in a wireless communication system according to an embodiment of the present disclosure.

Referring to fig. 6, simultaneous transmission and reception between an MT and a DU of an iab node means that an MT transmission or reception signal and a DU transmission or reception signal are simultaneously performed according to the multiplexing scheme described in fig. 2A and 2B.

Referring to fig. 6, reference numeral 601 denotes both MT and DU of one IAB node, respectively, transmitting signals. In case 601, a signal transmitted by an MT of an IAB node may be received by a DU of a parent IAB node or a gNB over a backhaul UL, as described with reference to fig. 3A, 3B, 4A, 4B, and 5. In case 601, a signal transmitted by a DU of an IAB node may be received by an MT of a sub-IAB node through a backhaul DL or may be received by an access UE through an access DL, as described with reference to fig. 3A, 3B, 4A, 4B, and 5.

Reference numeral 602 denotes an IAB node, both MT and DU respectively receiving signals. In case 602, the signal received by the MT of the IAB node may be a signal transmitted by a DU of a parent IAB node or a gNB through a backhaul DL, as described with reference to fig. 3A, 3B, 4A, 4B, and 5. In case 602, the signal simultaneously received by the DUs of the IAB node may be a signal transmitted by the MT of the sub-IAB node through the backhaul UL or may be a signal transmitted by the access UE through the access UL, as described with reference to fig. 3A, 3B, 4A, 4B, and 5.

Reference numeral 603 denotes an MT and DU of the IAB node to transmit and receive signals, respectively. That is, the MT of the IAB node may receive a signal and the DU of the IAB node may transmit a signal at the same time. In case 603, the signal received by the MT of the IAB node may be a signal transmitted by a DU of a parent IAB node or a gNB through a backhaul DL, as described with reference to fig. 3A, 3B, 4A, 4B, and 5. Further, in case 603, the signal simultaneously transmitted by the DUs of the IAB node may be received by the MT of the sub-IAB node through the backhaul DL or by the access UE through the access DL, as described with reference to fig. 3A, 3B, 4A, 4B, and 5.

Reference numeral 604 denotes an MT and DU of the IAB node to transmit and receive signals, respectively. That is, in case 603, the MT of the IAB node may transmit a signal, and the DU of the IAB node may simultaneously receive a signal. In case 604, a signal transmitted by an MT of an IAB node may be received by a DU of a parent IAB node or a gNB over a backhaul UL, as described with reference to fig. 3A, 3B, 4A, 4B, and 5. Further, in case 604, the signal simultaneously received by the DUs of the IAB node may be a signal transmitted by the MTs of the sub-IAB nodes through the backhaul UL or may be a signal transmitted by the access UE through the access UL, as described with reference to fig. 3A, 3B, 4A, 4B, and 5.

In this disclosure, embodiments will be provided for a method of aligning slot timing in a situation where both MT and DU of one IAB node transmit signals in case 601, and related procedures of a parent IAB node and an IAB node. The embodiments described below also apply to cases 602, 603 and 604 and case 601.

Fig. 7 is a diagram illustrating an embodiment of aligning backhaul transmission timing among IAB nodes in a wireless communication system according to an embodiment of the present disclosure.

Referring to fig. 7, a method of aligning DL transmission timing between DUs of an IAB node and a method of aligning DL transmission timing of a DU of one IAB node with UL transmission timing of an MT of an IAB node will be described. For the convenience of the present disclosure, aligning DL transmission timing between DUs of an IAB node in a slot i is referred to as case #1 timing, and aligning DL transmission timing of a DU of one IAB node with UL transmission timing of an MT of an IAB node in a slot i is referred to as case #6 timing. In the present disclosure, alignment of timing between a and B may refer to placing a time difference between first symbols of a and B within a Cyclic Prefix (CP) duration value corresponding to a subcarrier interval when a and B have the same subcarrier interval, and placing a time difference between first symbols of a and B within a CP duration value corresponding to a larger subcarrier interval when a and B have different subcarrier intervals.

Referring to FIG. 7, T _g The switching time between the DU DL transmission 714 and the DU UL reception 715 in the IAB1 701 as the gNB/parent IAB node is shown. The alignment between the timing of DL transmission 722 of IAB2 702 and the timing of DU DL transmission 714 of the gNB/parent IAB node IAB1 701 will be described, i.e., case #1 timing will be described. MT at propagation delay T of IAB2 702 ₁ After which a DU DL transmission 714 from IAB1 701 is received (716). The IAB2 702 may assume that the timing difference between the DU DL transmission 714 and DL reception 716 of the MT of the IAB2 702 is (e.g., (N) _TA /2+N _delta +T _delta ·G _step )·T _c To estimate the propagation delay time T ₁ 。N _TA Is the UL Timing Advance (TA) provided by IAB1 701. T (T) _delta Is provided by IAB1 701. IAB2 702 may receive N from IAB1 701 in a MAC signal _TA And T _delta 。N _delta And G _step Is a constant defined in the 5H system for frequency range 1 (FR 1) and frequency range 2 (FR 2). For FR1, for example, N _delta = -70528 and G _step For FR2, for example, =64,N _delta = -17444 and G _step ＝32。

The case #1 timing of IAB2 702 may be applied by applying the above timing difference based on DL reception 716 of the MT of IAB2 702. For timing of UL transmission 721 of IAB2 702, IAB2 702 is earlier than DL reception 716 of MT of IAB2 702 by UL TA N _TA Starts UL transmission 721 at the time of (c). That is, the timing of UL transmission 721 applied in the case #1 timing is adjusted in the same manner as the UL transmission timing adjustment procedure applied by the UE.

A case #6 timing scheme for aligning the timing of UL transmission 731 of the MT of IAB2 702 with the timing of DL transmission 732 of the DU of IAB2 702 will be described. In the present disclosure, three methods are presented.

First method

In the first method, the timing reference of UL transmission 731 of the MT is aligned (based on the timing of DL transmission 732 of DUs of IAB2 702. When IAB1 701 indicates IAB2 702 application #6 timing, IAB2 702 may align the timing of UL transmission 731 of the MT of IAB2 702 with the timing of DL transmissions 722 and 732 of the DUs of IAB2 702 determined by application #1 timing. However, over time, the timing of DL transmission 732 of the DU to be referenced may be less accurate. In the first approach, four schemes are proposed to maintain accuracy.

In a first approach, IAB2 702 may receive a timer value set by a higher layer signal. When IAB2 702 is instructed to time with application #6, IAB2 702 may count the timer. Only if the timer is not exceeded, IAB2 702 may apply case #6 timing (i.e., align the timing of MT UL transmission 731 with the timing of DU DL transmission 732). Upon exceeding the timer and expiration of the timer, the IAB2 702 may apply the case #1 case without continuing to apply the case #6 timing (i.e., based on the UL TA N _TA The timing of MT UL transmission 721).

In the second scheme, the IAB1 701 may indicate/provide information including a value required to adjust the DL transmission timing of the DU of the IAB2 702, thereby maintaining accuracy of the DL transmission timing of the DU to be referred to. The IAB2 702 may receive the indicated/providedInformation to adjust the timing of DU DL transmissions 722 and 732. For example, the indicated/provided information (value) may be a difference between the timing of the DU DL transmission 714 of IAB1 701 and the timing of the MT DL reception 716 of IAB2 702 (e.g., T in fig. 7) ₁ )。

In the third scheme, when the IAB2 702 receives the indicated/provided information (value) for adjusting the timing of the DU DL transmissions 722 and 732 within the set timer, the IAB2 702 applies the above second scheme, resets the timer count to 0, and performs the timer count again. The IAB2 702 applies the first scheme when no indicated/provided information (value) for adjusting the DU DL transmission timing within the set timer is received.

In the fourth scheme, even when the IAB2 702 is timed in the first method using the case #6, the IAB2 702 can receive the UL TA N from the IAB1 701 through the MAC signal _TA And T _delta . Instead of N _TA Timing applied to MT UL transmission 721, IAB2 702 may use N _TA The timing of the DU DL transmission 722 of IAB2 702 described by the contact #1 timing is aligned with the timing of the DU DL transmission 714 of IAB1 701. As described, N may not be _TA The timing applied to MT UL transmission 721, and the timing of MT UL transmission 731 may be aligned with the timing of DU DL transmission 732 according to case #6 timing.

The IAB2 702 may not receive the UL TA N previously received from the IAB1 701 or received from the IAB1 701 while applying the first scheme _TA Applied to MT UL transmission timing, or may not be expected to receive UL TA N _TA 。

An embodiment of signaling the IAB2 702 of the application case #1 timing or #6 timing by the IAB1 701 will be described. Before this, traffic (traffic) conditions of IAB2 702, in which simultaneous transmission of DUs and MTs is required, may be reported to IAB1 701. For example, the traffic condition may be information about a buffer status of UL/DL traffic or information about a buffer status of UL/DL traffic during a specific period of time (or a specific slot).

-signaling 1: bitmap information indicating whether case #6 timing or case #1 timing is applied to each slot by a higher layer signal, periodicity information, duration information, information on slots in which case #6 cannot be applied, and the like.

-signaling 2: including a higher layer signal of signaling 1 and a DL control signal indicating whether the higher layer signal is activated.

Signaling 3: including higher layer signals of a set of signaling 1 and DL control signals indicating one signaling 1 in the set.

Signaling 4: the bit field of the DL control signal of the UL data channel by the MT of the schedule IAB2 702 indicates whether case #6 timing is applied.

The IAB2 702 may receive signaling through a separate signaling scheme or a combination of signaling schemes and determine whether to apply case #1 timing or case #6 timing.

Second method

In the second method, UL transmission timing of MT with reference to (or based on) IAB2 702 aligns with DL transmission timing of DU.

When IAB1 701 indicates that IAB2 702 applies case #6 timing through the signaling scheme described in the first method, IAB1 701 may additionally indicate UL TA N for case #6 timing _TA And IAB2 702 may be configured to apply the additional UL TA N _TA And determining UL transmission timing of the MT and aligning DL transmission timing of the DU based on the determined UL transmission timing of the MT. For DL transmission timing of DUs, IAB1 701 may transmit T independent of the timing indication for case #1 _delta Additional T of (2) _delta . IAB2 702 may receive the UL TA and extra T timed for case #6 from IAB1 701 in the MAC signal _delta 。

Third method

In the third method, the IAB1 701 configures whether the IAB2 702 is to apply the first method or the second method through a higher layer signal. The IAB2 702 may receive a higher layer signal and apply case #6 timing by applying either the first method or the second method as configured by the higher layer signal.

In the case where the IAB2 702 alternately switches between the case #1 timing and the case #6 timing according to the instruction of the IAB1 701, when the UL transmission timing of the MT of the IAB2 702 advances by the case #1 timing or retreats by the case #6 timing, the UL transmission period based on the case #1 timing may overlap with the UL transmission period based on the case #6 timing. To address the overlap problem, IAB1 701 may indicate to IAB2 702 a guard period between the UL transmission period based on the case #1 timing and the UL transmission period based on the case #6 timing, and IAB2 702 may receive the indication. Alternatively, the IAB2 702 may report a required guard period between the UL transmission period based on the case #1 timing and the UL transmission period based on the case #6 timing, and the IAB1 701 may receive the report.

Fig. 8 illustrates a flowchart of the operation of a gNB/parent IAB node in a wireless communication system according to an embodiment of the disclosure.

Referring to fig. 8, in operation 801, IAB1 701 transmits information related to case #1 timing and case #6 timing to IAB2 702 of fig. 7 according to an embodiment of the present disclosure described in fig. 7, and receives necessary information from IAB2 702. The information related to the case #1 timing and the case #6 timing may be higher layer signals, signaling information, MAC signals, or the like, which the IAB1 701 provides to the IAB2 702 in the first to third methods. The necessary information may be various types of information reported to the IAB1 701 by the IAB2 702 in the first to third methods, such as information on traffic conditions and information on guard periods. In operation 802, IAB1 701 receives a signal from IAB2 702 on the backhaul UL by applying a case #1 timing or a case #6 timing according to an embodiment of the present disclosure described with reference to fig. 7.

Fig. 9 is a flowchart illustrating an operation of an IAB node in a wireless communication system according to an embodiment of the present disclosure.

Referring to fig. 9, in operation 901, according to an embodiment of the present disclosure described in fig. 7, IAB2 702 of fig. 7 receives information related to case #1 timing and case #6 timing of IAB1 701 of fig. 7, and transmits necessary information to IAB1 701. In operation 902, according to an embodiment of the present disclosure described with reference to fig. 7, IAB2 702 transmits a signal to IAB1 701 on the backhaul UL and to a lower (sub) IAB node on the backhaul DL or to an access UE on the access DL by applying the case #1 timing or the case #6 timing.

To perform the above-described embodiments of the present disclosure, fig. 10 and 11 show the transmitter, receiver, and processor of the UE and the gNB, respectively. The transmitter and receiver may be referred to as transceivers. Fig. 12 also shows the apparatus of the IAB node. In the 5G communication system described in the above embodiments, when signals are transmitted and received over the backhaul link or over the access link by the IAB node, a method of transmitting and receiving signals by a gNB (home gNB) transmitting and receiving signals to and from the IAB node and by a UE transmitting and receiving signals to and from the IAB node is described. To perform the method, the transmitter, receiver, and processor of each of the gNB, the UE, and the IAB node may operate according to an embodiment.

Fig. 10 is a diagram illustrating a configuration of a UE according to an embodiment of the present disclosure.

Referring to fig. 10, a UE of the present disclosure may include a processor 1001, a receiver 1002, and a transmitter 1003.

The processor 1001 may control a series of processes in which the UE operates according to the aforementioned embodiments of the present disclosure (alone or in combination) shown in fig. 1, 2A, 2B, 3A, 3B, 4A, 4B, 5, 6, 7, and 8. For example, the processor 1001 may control access link transmission and reception to and from the IAB node differently according to embodiments of the present disclosure. In embodiments of the present disclosure, the receiver 100 and the transmitter 1003 may be collectively referred to as a transceiver. The transceiver may transmit and receive signals to and from the gNB. The signal may include at least one of control information and data. To this end, the transceiver may include an RF transmitter for up-converting and amplifying the frequency of the transmitted signal and an RF receiver for low noise amplifying and down-converting the received signal. Further, the transceiver may receive a signal on a radio channel and output the received signal to the processor 1001, and may transmit a signal received from the processor 1001 on the radio channel.

Fig. 11 is a diagram showing a configuration of a gNB (host gNB) according to an embodiment of the present disclosure.

Referring to fig. 11, a gNB of the present disclosure may include a processor 1101, a receiver 1102, and a transmitter 1103.

The processor 1101 may control a series of processes in which the gNB operates in accordance with the embodiments of the present disclosure illustrated in fig. 1, 2A, 2B, 3A, 3B, 4A, 4B, 5, 6, 7, and 8 described above. For example, the processor 1101 may control backhaul link transmission and reception and access link transmission reception to and from an IAB node differently according to embodiments of the present disclosure. In embodiments of the present disclosure, the receiver 1102 and the transmitter 1103 may be collectively referred to as a transceiver. The transceiver transmits/receives signals to/from the UE or the (sub) IAB node. The signal may include at least one of control information and data. To this end, the transceiver may include an RF transmitter for up-converting and amplifying the frequency of the transmitted signal and an RF receiver for low noise amplifying and down-converting the received signal. Further, the transceiver may receive signals on a radio channel and output the received signals to the processor 1101, and may transmit signals received from the processor 1101 on the radio channel.

Fig. 12 is a diagram illustrating a configuration of an IAB node according to an embodiment of the present disclosure.

Referring to fig. 12, an IAB node of the present disclosure may include a gNB function controller 1201, a gNB function receiver 1202, and a gNB function transmitter 1203 for transmission and reception to and from a lower (child) IAB node on the backhaul link. Further, the IAB node may comprise a UE function controller 1211, a UE function receiver 1212 and a UE function transmitter 1213 for initial access to the higher (parent) IAB node and/or the hosting gNB, transmission and reception of higher layer signals prior to transmission and reception on the backhaul link, and transmission and reception to and from the higher (parent) IAB node and/or the hosting gNB on the (radio) backhaul link.

According to embodiments of the present disclosure, the gcb function controller 1201 of the IAB node may control a series of processes in which the IAB node operates like a gcb. For example, the gNB function controller 1201 may perform the functions of a DU of an IAB node as described above. For example, the gNB function controller 1201 may control transmission and reception to and from a lower IAB node on the backhaul link and transmission and reception to and from the UE on the access link differently. In embodiments of the present disclosure, the gNB function receiver 1202 and the gNB function transmitter 1203 may be collectively referred to as a first transceiver. The first transceiver may transmit/receive signals to/from the UE or a lower (sub) IAB node. The signal may include at least one of control information and data. To this end, the first transceiver may include an RF transmitter for up-converting and amplifying the frequency of the transmitted signal and an RF receiver for low noise amplifying and down-converting the received signal. Further, the first transceiver may receive a signal on a radio channel and output the received signal to the gNB function controller 1201, and may transmit a signal received from the gNB function controller 1201 on the radio channel.

According to embodiments of the present disclosure, the UE function controller 1211 of the IAB node may control a series of procedures in which a lower (child) IAB node may operate like a UE for data transmission and reception to and from the home gcb or a higher (parent) IAB node. For example, the UE function controller 1211 may perform the functions of the MT of the IAB node as described above. For example, the UE functional controller 1211 may control the transmission and reception to and from the hosting gNB and/or higher (parent) IAB nodes on the (radio) backhaul link differently. In embodiments of the present disclosure, the UE function receiver 1212 and the UE function transmitter 1213 may be collectively referred to as a second transceiver. The second transceiver may transmit and receive signals to and from the host gNB and the higher (parent) IAB node. The signal may include at least one of control information and data. To this end, the second transceiver may include an RF transmitter for up-converting and amplifying the frequency of the transmitted signal and an RF receiver for low noise amplifying and down-converting the received signal. Further, the second transceiver may receive a signal on a radio channel and output the received signal to the UE function controller 1211, and may transmit a signal received from the UE function controller 1211 on the radio channel.

The nb function controller 1201 of the IAB node and the UE function controller 1211 of the IAB node in fig. 12 may be integrated as an IAB node controller. In this case, the IAB node controller 1200 may control the functions of the DU and the MT together in the IAB node. The gNB function controller 1201, the UE function controller 1211, and the IAB node controller may be implemented as at least one processor. The first transceiver and the second transceiver may be provided separately or may be provided as one integrated transceiver.

While the present disclosure has been shown and described with reference to various embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present disclosure as defined by the appended claims and their equivalents.

Claims (15)

1. A method for transmitting signals by an Integrated Access and Backhaul (IAB) Mobile Terminal (MT) and an IAB Distributed Unit (DU) via a backhaul link between a parent IAB node and a child IAB node in a wireless communication system, the method comprising:

receiving signaling information indicating a timing scheme to be applied to the IAB-MT from the parent IAB node; and

in the case where the indicated timing scheme is a first timing scheme in which the transmission timing of the IAB MT coincides with the transmission timing of the IAB DU, a signal is transmitted by the IAB-MT to the parent IAB node in a backhaul uplink and a signal is transmitted by the IAB-DU to the child IAB node in a backhaul downlink,

Wherein the transmission timing at which the IAB-MT transmits the signal and the transmission timing at which the IAB-DU transmits the signal are set identically.

2. The method of claim 1, wherein the transmission timing of the IAB-MT is set identically based on the transmission timing of the IAB-DU.

3. The method of claim 1, wherein the signaling information is received using a Medium Access Control (MAC) signal.

4. The method of claim 1, wherein the indicated timing scheme is set in units of time slots.

5. The method of claim 1, further comprising transmitting, by the IAB MT, a signal based on information about a Timing Advance (TA) received from the parent IAB node if the indicated timing scheme is a second timing scheme using TA applied to uplink transmission of the IAB-MT.

6. An Integrated Access and Backhaul (IAB) node for transmitting a signal via a backhaul link between the IAB node and a child IAB node in a wireless communication system, the IAB node comprising:

an IAB Mobile Terminal (MT) configured to:

receiving signaling information indicating a timing scheme to be applied to the IAB-MT from the parent IAB node; and

Transmitting a signal to the parent IAB node in a backhaul uplink; and

an IAB Distributed Unit (DU) configured to transmit signals to the sub-IAB nodes in a backhaul downlink,

wherein, in the case where the indicated timing scheme is a first timing scheme in which the transmission timing of the IAB MT coincides with the transmission timing of the IAB DU, the transmission timing at which the IAB-MT transmits the signal and the transmission timing at which the IAB-DU transmits the signal are set identically.

7. The IAB node according to claim 6, adapted to operate according to one of claims 2 to 5.

8. An Integrated Access and Backhaul (IAB) node for transmitting a signal via a backhaul link between the IAB node and a child IAB node in a wireless communication system, the IAB node comprising:

at least one transceiver; and

a controller coupled with the at least one transceiver, the controller configured to:

the parent IAB node receives signaling information indicating a timing scheme to be applied; and

in the case where the indicated timing scheme is a first timing scheme in which the transmission timing of the IAB MT of the IAB node coincides with the transmission timing of the IAB DU of the IAB node, transmitting a signal to the parent IAB node in a backhaul uplink and transmitting a signal to the child IAB node in a backhaul downlink,

Wherein the transmission timing at which the IAB-MT transmits the signal and the transmission timing at which the IAB-DU transmits the signal are set identically.

9. The IAB node of claim 8, wherein a transmission timing of the IAB-MT is set identically based on a transmission timing of the IAB-DU.

10. The IAB node of claim 8, wherein the signaling information is received using a Medium Access Control (MAC) signal.

11. The IAB node of claim 8, wherein the indicated timing scheme is set in units of slots.

12. The IAB node of claim 8, wherein, if the indicated timing scheme is a second timing scheme using a Timing Advance (TA) applied to uplink transmission of the IAB-MT, the controller is configured to transmit a signal based on information about a TA received from the parent IAB node.

13. A method for receiving a signal by a parent Integrated Access and Backhaul (IAB) node via a backhaul link between the parent node and an IAB node in a wireless communication system, the method comprising:

transmitting signaling information indicating a timing scheme to be applied to the IAB node including an IAB Mobile Terminal (MT) and an IAB Distributed Unit (DU); and

In the case where the indicated timing scheme is a first timing scheme in which the transmission timing of the IAB MT coincides with the transmission timing of the IAB DU, the signal is received from the IAB-MT via the backhaul link,

wherein the transmission timings of the IAB-MT and the IAB-DU are set identically based on the signaling information.

14. The method of claim 13, wherein the signaling information is received using a Medium Access Control (MAC) signal, and

wherein the indicated timing scheme is set in units of time slots.

15. A parent Integrated Access and Backhaul (IAB) node for receiving a signal via a backhaul link between the parent IAB node and an IAB node in a wireless communication system, the parent IAB node comprising:

at least one transceiver; and

a controller coupled with the at least one transceiver, the controller configured to:

transmitting signaling information indicating a timing scheme to be applied to an IAB node from the IAB node including an IAB Mobile Terminal (MT) and an IAB Distributed Unit (DU); and

in the case where the indicated timing scheme is a first timing scheme in which the transmission timing of the IAB MT coincides with the transmission timing of the IAB DU, the signal is received from the IAB-MT via the backhaul link,

Wherein the transmission timings of the IAB-MT and the IAB-DU are set identically based on the signaling information.