WO2023014187A1

WO2023014187A1 - Method and apparatus for reducing bandwidth part switching delay time in wireless communication system

Info

Publication number: WO2023014187A1
Application number: PCT/KR2022/011695
Authority: WO
Inventors: 김재민; 지형주; 장영록
Original assignee: 삼성전자 주식회사
Priority date: 2021-08-06
Filing date: 2022-08-05
Publication date: 2023-02-09
Also published as: KR20230021972A

Abstract

The present disclosure provides a BWP switching method performed by a terminal in a wireless communication system. The method comprises the steps of: identifying a first bandwidth part (BWP) associated with a first communication direction and a plurality of BWPs associated with a second communication direction, the plurality of BWPs associated with the second communication direction including a second BWP and a third BWP having a bandwidth size greater than a bandwidth size of the second BWP, and center frequencies of the first BWP and the third BWP being same; receiving information indicating switching from the first BWP to the second BWP; and switching from the first BWP to the second BWP on the basis of the information, wherein a guard period required for the switching from the first BWP to the second BWP is determined on the basis of whether center frequencies of the second BWP and the third BWP are same and whether the second BWP and the third BWP overlap in a frequency domain.

Description

Method and apparatus for reducing bandwidth part change delay time in wireless communication system

The present disclosure relates to a method and apparatus for transmitting and receiving signals in a wireless communication system, and more particularly, to a method and apparatus for reducing a delay time occurring when changing a bandwidth part (BWP).

5G mobile communication technology defines a wide frequency band to enable fast transmission speed and new services. It can also be implemented in the ultra-high frequency band ('Above 6GHz') called Wave. In addition, in the case of 6G mobile communication technology, which is called a system after 5G communication (Beyond 5G), in order to achieve transmission speed that is 50 times faster than 5G mobile communication technology and ultra-low latency reduced to 1/10, tera Implementations in Terahertz bands (eg, such as the 3 Terahertz (3 THz) band at 95 GHz) are being considered.

In the early days of 5G mobile communication technology, there was a need for enhanced mobile broadband (eMBB), ultra-reliable low-latency communications (URLLC), and massive machine-type communications (mMTC). Beamforming and Massive MIMO to mitigate the path loss of radio waves in the ultra-high frequency band and increase the propagation distance of radio waves, with the goal of satisfying service support and performance requirements, and efficient use of ultra-high frequency resources Various numerology support (multiple subcarrier interval operation, etc.) and dynamic operation for slot format, initial access technology to support multi-beam transmission and broadband, BWP (Band-Width Part) definition and operation, large capacity New channel coding methods such as LDPC (Low Density Parity Check) code for data transmission and Polar Code for reliable transmission of control information, L2 pre-processing, and dedicated services specialized for specific services Standardization of network slicing that provides a network has been progressed.

Currently, discussions are underway to improve and enhance performance of the initial 5G mobile communication technology in consideration of the services that the 5G mobile communication technology was intended to support. NR-U (New Radio Unlicensed) for the purpose of system operation that meets various regulatory requirements in unlicensed bands ), NR terminal low power consumption technology (UE Power Saving), non-terrestrial network (NTN), which is direct terminal-satellite communication to secure coverage in areas where communication with the terrestrial network is impossible, positioning, etc. Physical layer standardization of the technology is in progress.

In addition, IAB (Industrial Internet of Things (IIoT)), which provides nodes for expanding network service areas by integrating wireless backhaul links and access links, to support new services through linkage and convergence with other industries (Industrial Internet of Things, IIoT) Integrated Access and Backhaul), Mobility Enhancement technology including conditional handover and Dual Active Protocol Stack (DAPS) handover, 2-step random access that simplifies the random access procedure (2-step RACH for Standardization in the field of air interface architecture/protocol for technologies such as NR) is also in progress, and 5G　baseline for grafting Network Functions Virtualization (NFV) and Software-Defined Networking (SDN) technologies Standardization in the field of system architecture/service is also in progress for an architecture (eg, service based architecture, service based interface), mobile edge computing (MEC) for which services are provided based on the location of a terminal, and the like.

When such a 5G mobile communication system is commercialized, the explosively increasing number of connected devices will be connected to the communication network, and accordingly, it is expected that the function and performance enhancement of the 5G mobile communication system and the integrated operation of connected devices will be required. To this end, augmented reality (AR), virtual reality (VR), mixed reality (MR), etc. to efficiently support extended reality (XR), artificial intelligence (AI) , AI) and machine learning (ML), new research on 5G performance improvement and complexity reduction, AI service support, metaverse service support, and drone communication will be conducted.

In addition, the development of such a 5G mobile communication system is a new waveform, Full Dimensional MIMO (FD-MIMO), and Array Antenna for guaranteeing coverage in the terahertz band of 6G mobile communication technology. , multi-antenna transmission technologies such as large scale antennas, metamaterial-based lenses and antennas to improve coverage of terahertz band signals, high-dimensional spatial multiplexing technology using Orbital Angular Momentum (OAM), RIS ( Reconfigurable Intelligent Surface) technology, as well as full duplex technology to improve frequency efficiency and system network of 6G mobile communication technology, satellite, and AI (Artificial Intelligence) are utilized from the design stage and end-to-end (End-to-End) -to-End) Development of AI-based communication technology that realizes system optimization by internalizing AI-supported functions and next-generation distributed computing technology that realizes complex services beyond the limits of terminal computing capabilities by utilizing ultra-high-performance communication and computing resources could be the basis for

An object of the present disclosure is to provide a method and method for reducing delay time occurring when a bandwidth part is changed in a wireless communication system through the disclosed embodiments.

In order to solve the above problems, an embodiment of the present disclosure provides a method performed by a terminal in a wireless communication system. The method includes identifying a first bandwidth part (BWP) associated with a first communication direction and a plurality of BWPs associated with a second communication direction, wherein the plurality of BWPs associated with the second communication direction are the second BWP and the second BWP. a third BWP having a bandwidth size greater than that of the BWP, and center frequencies of the first BWP and the third BWP are the same; Receiving information indicating a change from the first BWP to the second BWP; and changing from the first BWP to the second BWP based on the information, wherein a protection time required for changing from the first BWP to the second BWP is between the second BWP and the third BWP. It may be determined based on whether the center frequencies are the same and whether the second BWP and the third BWP overlap in the frequency domain.

In addition, an embodiment of the present disclosure provides a method performed by a base station in a wireless communication system. The method includes transmitting configuration information for configuring a first bandwidth part (BWP) associated with a first communication direction and a plurality of BWPs associated with a second communication direction to a terminal, wherein the plurality of BWPs associated with the second communication direction are A second BWP and a third BWP having a bandwidth size greater than that of the second BWP, wherein the center frequencies of the first BWP and the third BWP are the same; And transmitting, to the terminal, information indicating a change from the first BWP to the second BWP, wherein the first BWP is changed to the second BWP based on the information, and the first The guard time required for changing from the BWP to the second BWP is determined based on whether the center frequencies of the second BWP and the third BWP are the same and whether the second BWP and the third BWP overlap in the frequency domain. can

In addition, an embodiment of the present disclosure provides a terminal including a transceiver for transmitting and receiving signals in a wireless communication system, and a control unit connected to the transceiver. The control unit of the terminal identifies a first bandwidth part (BWP) associated with a first communication direction and a plurality of BWPs associated with a second communication direction, and the plurality of BWPs associated with the second communication direction determine the second BWP and the second communication direction. Includes a third BWP having a bandwidth size greater than that of the second BWP, center frequencies of the first BWP and the third BWP are the same, and indicates a change from the first BWP to the second BWP information is received, and based on the information, the first BWP is set to change to the second BWP, and the protection time required for changing from the first BWP to the second BWP is determined by the second BWP and the second BWP. It may be determined based on whether the center frequencies of the third BWP are the same and whether the second BWP and the third BWP overlap in the frequency domain.

In addition, an embodiment of the present disclosure provides a base station including a transceiver for transmitting and receiving signals in a wireless communication system, and a control unit connected to the transceiver. The control unit of the base station transmits configuration information for configuring a first bandwidth part (BWP) associated with a first communication direction and a plurality of BWPs associated with a second communication direction to the terminal, and the plurality of BWPs associated with the second communication direction. include a second BWP and a third BWP having a bandwidth size greater than the bandwidth size of the second BWP, the center frequencies of the first BWP and the third BWP are the same, and to the terminal, the It is configured to transmit information indicating a change from 1 BWP to the second BWP, and based on the information, the first BWP is changed to the second BWP, and the change from the first BWP to the second BWP The required guard time may be determined based on whether the center frequencies of the second BWP and the third BWP are the same and whether the second BWP and the third BWP overlap in the frequency domain.

The technical problems to be achieved in the embodiments of the present disclosure are not limited to the above-mentioned technical problems, and other technical problems not mentioned are clear to those skilled in the art from the description below. will be understandable.

According to various embodiments of the present disclosure, an apparatus and method capable of effectively providing a service in a wireless communication system may be provided.

In addition, according to an embodiment of the present disclosure, a delay time occurring when changing a bandwidth part can be reduced.

1 is a diagram showing the basic structure of a time-frequency domain in a 5G system.

2 is a diagram illustrating a frame, subframe, and slot structure in a 5G system.

3 is a diagram illustrating an example of setting a bandwidth part in a 5G system.

4 is a diagram illustrating an example of setting a control region of a downlink control channel in a 5G system.

5 is a diagram showing the structure of a downlink control channel in a 5G system.

6 is a diagram illustrating an example of a method for setting a bandwidth part according to some embodiments of the present disclosure.

7 is a diagram illustrating uplink and downlink settings according to an embodiment of the present disclosure.

8 is a diagram illustrating settings of an uplink bandwidth part and a downlink bandwidth part according to an embodiment of the present disclosure.

9 is a block diagram illustrating a procedure for reporting a UE capability from a UE to a base station according to an embodiment of the present disclosure.

10A is a diagram illustrating a bandwidth part configured by a terminal from a base station according to an embodiment of the present disclosure.

10B is a diagram illustrating a bandwidth part configured by a terminal from a base station according to an embodiment of the present disclosure.

11 is a diagram illustrating a bandwidth part configured by a terminal from a base station according to an embodiment of the present disclosure.

12 is a diagram illustrating a bandwidth part configured by a terminal from a base station according to an embodiment of the present disclosure.

13 is a diagram illustrating a bandwidth part configured by a terminal from a base station according to an embodiment of the present disclosure.

14 is a diagram illustrating a bandwidth part configured by a terminal from a base station according to an embodiment of the present disclosure.

15 is a diagram illustrating a bandwidth part configured by a terminal from a base station according to an embodiment of the present disclosure.

16 is a diagram illustrating a bandwidth part configured by a terminal from a base station according to an embodiment of the present disclosure.

17 is a diagram illustrating a bandwidth part configured by a terminal from a base station according to an embodiment of the present disclosure.

18 is a block diagram illustrating a procedure for determining a guard time generated when a terminal changes from downlink to uplink according to characteristics of a bandwidth part set by a base station according to an embodiment of the present disclosure.

19 is a block diagram illustrating a procedure for determining a guard time generated when a terminal changes from downlink to uplink according to characteristics of a bandwidth part set by a base station according to an embodiment of the present disclosure.

20 is an example of an operation flowchart of a terminal according to an embodiment of the present disclosure.

21 is a diagram illustrating a structure of a terminal in a wireless communication system according to an embodiment of the present disclosure.

22 is a diagram illustrating a structure of a base station in a wireless communication system according to an embodiment of the present disclosure.

Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings.

In describing the embodiments, descriptions of technical contents that are well known in the technical field to which the present disclosure pertains and are not directly related to the present disclosure will be omitted. This is to more clearly convey the gist of the present disclosure without obscuring it by omitting unnecessary description.

For the same reason, in the accompanying drawings, some components are exaggerated, omitted, or schematically illustrated. Also, the size of each component does not entirely reflect the actual size. In each figure, the same reference number is given to the same or corresponding component.

Advantages and features of the present disclosure, and methods of achieving them, will become clear with reference to the embodiments described below in detail in conjunction with the accompanying drawings. However, the present disclosure is not limited to the embodiments disclosed below and may be implemented in various different forms, only the present embodiments make the disclosure of the present disclosure complete, and common knowledge in the art to which the present disclosure belongs. It is provided to fully inform the person who has the scope of the disclosure, and the disclosure is only defined by the scope of the claims. Like reference numbers designate like elements throughout the specification. In addition, in describing the present disclosure, if it is determined that a detailed description of a related function or configuration may unnecessarily obscure the subject matter of the present disclosure, the detailed description will be omitted. In addition, terms to be described later are terms defined in consideration of functions in the present disclosure, which may vary according to intentions or customs of users or operators. Therefore, the definition should be made based on the contents throughout this specification.

Hereinafter, a base station is a subject that performs resource allocation of a terminal, and may be at least one of a gNode B, an eNode B, a Node B, a base station (BS), a wireless access unit, a base station controller, or a node on a network. The terminal may include a user equipment (UE), a mobile station (MS), a cellular phone, a smart phone, a computer, or a multimedia system capable of performing communication functions. In the present disclosure, downlink (DL) is a radio transmission path of a signal transmitted from a base station to a terminal, and uplink (UL) refers to a radio transmission path of a signal transmitted from a terminal to a base station. In addition, although a long-term evolution (LTE) or LTE-advanced (LTE-A) system may be described below as an example, embodiments of the present disclosure may be applied to other communication systems having a similar technical background or channel type. . For example, the 5th generation mobile communication technology (5G, new radio, NR) developed after LTE-A may be included in this, and the following 5G may be a concept including existing LTE, LTE-A and other similar services there is. In addition, the present disclosure can be applied to other communication systems through some modifications within a range that does not greatly deviate from the scope of the present disclosure as determined by those skilled in the art.

At this time, it will be understood that each block of the process flow chart diagrams and combinations of the flow chart diagrams can be performed by computer program instructions. These computer program instructions may be embodied in a processor of a general purpose computer, special purpose computer, or other programmable data processing equipment, so that the instructions executed by the processor of the computer or other programmable data processing equipment are described in the flowchart block(s). It creates means to perform functions. These computer program instructions may also be stored in a computer usable or computer readable memory that can be directed to a computer or other programmable data processing equipment to implement functionality in a particular way, such that the computer usable or computer readable memory The instructions stored in are also capable of producing an article of manufacture containing instruction means that perform the functions described in the flowchart block(s). The computer program instructions can also be loaded on a computer or other programmable data processing equipment, so that a series of operational steps are performed on the computer or other programmable data processing equipment to create a computer-executed process to generate computer or other programmable data processing equipment. Instructions for performing processing equipment may also provide steps for performing the functions described in the flowchart block(s).

Additionally, each block may represent a module, segment, or portion of code that includes one or more executable instructions for executing specified logical function(s). It should also be noted that in some alternative implementations it is possible for the functions mentioned in the blocks to occur out of order. For example, it is possible that two blocks shown in succession may in fact be performed substantially concurrently, or that the blocks may sometimes be performed in reverse order depending on their function.

At this time, the term '~unit' used in this embodiment means software or hardware components such as FPGA (Field Programmable Gate Array) or ASIC (Application Specific Integrated Circuit), and '~unit' performs certain roles. do. However, '~ part' is not limited to software or hardware. '~bu' may be configured to be in an addressable storage medium and may be configured to reproduce one or more processors. Therefore, as an example, '~unit' refers to components such as software components, object-oriented software components, class components, and task components, processes, functions, properties, and procedures. , subroutines, segments of program code, drivers, firmware, microcode, circuitry, data, databases, data structures, tables, arrays, and variables. Functions provided within components and '~units' may be combined into smaller numbers of components and '~units' or further separated into additional components and '~units'. In addition, components and '~units' may be implemented to reproduce one or more central processing units (CPUs) in a device or a secure multimedia card. Also, in the embodiment, '~ unit' may include one or more processors.

The wireless communication system has moved away from providing voice-oriented services in the early days and, for example, 3GPP's HSPA (High Speed Packet Access), LTE (Long Term Evolution or E-UTRA (Evolved Universal Terrestrial Radio Access)), LTE-Advanced (LTE-A), LTE-Pro, 3GPP2's High Rate Packet Data (HRPD), UMB (Ultra Mobile Broadband), and IEEE's 802.16e, a broadband wireless network that provides high-speed, high-quality packet data services. evolving into a communication system.

As a representative example of the broadband wireless communication system, in the LTE system, an Orthogonal Frequency Division Multiplexing (OFDM) method is employed in downlink (DL), and SC-FDMA (Single Carrier Frequency Division Multiplexing) in uplink (UL) Access) method is used. Uplink refers to a radio link in which a terminal (UE (User Equipment) or MS (Mobile Station)) transmits data or control signals to a base station (eNode B or base station (BS)), and downlink refers to a radio link in which a base station transmits data or a control signal to a terminal. A radio link that transmits data or control signals. The multiple access scheme as described above can distinguish data or control information of each user by allocating and operating time-frequency resources to carry data or control information for each user so that they do not overlap each other, that is, so that orthogonality is established. can

As a future communication system after LTE, that is, a 5G communication system, since it should be able to freely reflect various requirements such as users and service providers, a service that satisfies various requirements at the same time must be supported. Services considered for the 5G communication system include enhanced mobile broadband (eMBB), massive machine type communication (mMTC), ultra reliability low latency communication (URLLC), etc. there is

eMBB aims to provide a data transmission rate that is more improved than that supported by existing LTE, LTE-A or LTE-Pro. For example, in a 5G communication system, an eMBB must be able to provide a peak data rate of 20 Gbps in downlink and a peak data rate of 10 Gbps in uplink from the perspective of one base station. In addition, the 5G communication system should provide a maximum transmission rate and, at the same time, an increased user perceived data rate of the terminal. In order to satisfy these requirements, improvements in various transmission and reception technologies including a more advanced multi-input multi-output (MIMO) transmission technology are required. In addition, while signals are transmitted using a maximum 20MHz transmission bandwidth in the 2GHz band used by LTE, the 5G communication system uses a frequency bandwidth wider than 20MHz in a frequency band of 3 to 6GHz or 6GHz or higher, thereby providing data required by the 5G communication system. transmission speed can be satisfied.

At the same time, mMTC is being considered to support application services such as Internet of Things (IoT) in 5G communication systems. In order to efficiently provide the Internet of Things, mMTC requires access support for large-scale terminals within a cell, improved coverage of terminals, improved battery time, and reduced terminal cost. Since the Internet of Things is attached to various sensors and various devices to provide communication functions, it must be able to support a large number of terminals (eg, 1,000,000 terminals/km2) in a cell. In addition, since a terminal supporting mMTC is likely to be located in a shadow area that is not covered by a cell, such as the basement of a building due to the nature of the service, it may require a wider coverage than other services provided by the 5G communication system. A terminal supporting mMTC must be composed of a low-cost terminal, and since it is difficult to frequently replace a battery of the terminal, a very long battery life time such as 10 to 15 years may be required.

Finally, in the case of URLLC, it is a cellular-based wireless communication service used for a specific purpose (mission-critical). For example, remote control of robots or machinery, industrial automation, unmaned aerial vehicles, remote health care, emergency situations A service used for emergency alert or the like may be considered. Therefore, the communication provided by URLLC must provide very low latency and very high reliability. For example, a service supporting URLLC needs to satisfy an air interface latency of less than 0.5 milliseconds, and at the same time has a requirement of a packet error rate of 10 ^-5 or less. Therefore, for a service that supports URLLC, a 5G system must provide a smaller transmit time interval (TTI) than other services, and at the same time, a design that allocates wide resources in the frequency band to secure the reliability of the communication link. items may be requested.

The three services of 5G, namely eMBB, URLLC, and mMTC, can be multiplexed and transmitted in one system. At this time, different transmission/reception techniques and transmission/reception parameters may be used between services in order to satisfy different requirements of each service. Of course, 5G is not limited to the three services mentioned above.

[NR time-frequency resource]

Hereinafter, the frame structure of the 5G system will be described in more detail with reference to the drawings.

1 is a diagram showing the basic structure of a time-frequency domain, which is a radio resource domain in which data or control channels are transmitted in a 5G system.

1, the horizontal axis represents the time domain, and the vertical axis represents the frequency domain. The basic unit of resources in the time and frequency domains is a resource element (RE, 101), which is defined as 1 Orthogonal Frequency Division Multiplexing (OFDM) symbol 102 in the time axis and 1 subcarrier 103 in the frequency axis. It can be. in the frequency domain

(For example, 12) consecutive REs may constitute one resource block (Resource Block, RB, 104). In the time domain, 14 consecutive OFDM symbols may constitute one slot, and a time interval of 1 ms may constitute one subframe 110.

2 is a diagram illustrating a frame, subframe, and slot structure in a wireless communication system according to an embodiment of the present disclosure.

2 shows an example of a structure of a frame (Frame, 200), a subframe (Subframe, 201), and a slot (Slot, 202). One frame 200 may be defined as 10 ms. One subframe 201 may be defined as 1 ms, and therefore, one frame 200 may consist of a total of 10 subframes 201 . One slot (202, 203) may be defined as 14 OFDM symbols (that is, the number of symbols per slot (

)=14). One subframe 201 may consist of one or a plurality of

slots

202 and 203, and the number of

slots

202 and 203 per one subframe 201 is a set value for the subcarrier interval μ(204, 205 ) may vary. In an example of FIG. 2 , a case where μ=0 (204) and a case where μ=1 (205) are shown as the subcarrier interval setting value. When μ = 0 (204), 1 subframe 201 may consist of one slot 202, and when μ = 1 (205), 1 subframe 201 may consist of two slots 203 may consist of That is, the number of slots per 1 subframe according to the setting value μ for the subcarrier interval (

) may vary, and accordingly, the number of slots per frame (

) may vary. According to each subcarrier spacing setting μ

and

Can be defined in Table 1 below.

[Bandwidth Part (BWP)]

Next, the bandwidth part (BWP) setting in the 5G communication system will be described in detail with reference to the drawings.

3 is a diagram illustrating an example of setting a bandwidth portion in a wireless communication system according to an embodiment of the present disclosure.

3 shows an example in which the UE bandwidth 300 is set to two bandwidth parts, that is, bandwidth part # 1 (BWP # 1) 301 and bandwidth part # 2 (BWP # 2) 302. show The base station may set one or a plurality of bandwidth parts to the terminal, and may set the following information for each bandwidth part.

Of course, it is not limited to the above example, and various parameters related to the bandwidth part may be set in the terminal in addition to the setting information. The information may be transmitted from the base station to the terminal through higher layer signaling, for example, radio resource control (RRC) signaling. At least one bandwidth part among one or a plurality of set bandwidth parts may be activated. Whether or not the set bandwidth portion is activated may be semi-statically transmitted from the base station to the terminal through RRC signaling or dynamically transmitted through downlink control information (DCI).

According to some embodiments, a terminal before RRC (Radio Resource Control) connection may receive an initial bandwidth portion (Initial BWP) for initial access from a base station through a Master Information Block (MIB). More specifically, in the initial access step, the terminal receives system information (remaining system information; RMSI or System Information Block 1; may correspond to SIB1) necessary for initial access through the MIB. PDCCH for receiving can be transmitted Setting information on a control resource set (CORESET) and a search space may be received. The control area and search space set by MIB can be regarded as identity (ID) 0, respectively. The base station may notify the terminal of setting information such as frequency allocation information, time allocation information, and numerology for the control region #0 through the MIB. In addition, the base station may notify the terminal of configuration information about the monitoring period and occasion for control region #0, that is, configuration information about search space #0, through the MIB. The terminal may regard the frequency domain set as the control domain #0 acquired from the MIB as an initial bandwidth part for initial access. At this time, the identifier (ID) of the initial bandwidth part may be regarded as 0.

The setting for the portion of the bandwidth supported by 5G can be used for various purposes.

According to some embodiments, when the bandwidth supported by the terminal is smaller than the system bandwidth, it can be supported through the bandwidth portion setting. For example, the base station can transmit and receive data at a specific frequency position within the system bandwidth by setting the frequency position (configuration information 2) of the bandwidth part to the terminal.

Also, according to some embodiments, the base station may set a plurality of bandwidth parts to the terminal for the purpose of supporting different numerologies. For example, in order to support both data transmission and reception using a subcarrier spacing of 15 kHz and a subcarrier spacing of 30 kHz to a terminal, two bandwidth parts may be set to subcarrier spacings of 15 kHz and 30 kHz, respectively. Different bandwidth parts may be frequency division multiplexed, and when data is to be transmitted/received at a specific subcarrier interval, a bandwidth portion set at a corresponding subcarrier interval may be activated.

Also, according to some embodiments, for the purpose of reducing the power consumption of the terminal, the base station may set bandwidth parts having different sizes of bandwidth to the terminal. For example, when a terminal supports a very large bandwidth, for example, a bandwidth of 100 MHz and always transmits and receives data with the corresponding bandwidth, very large power consumption may occur. In particular, monitoring an unnecessary downlink control channel with a large bandwidth of 100 MHz in a non-traffic situation may be very inefficient in terms of power consumption. For the purpose of reducing power consumption of the terminal, the base station may set a bandwidth part of a relatively small bandwidth, for example, a bandwidth part of 20 MHz for the terminal. In a situation where there is no traffic, the terminal can perform a monitoring operation in the 20 MHz bandwidth part, and when data is generated, it can transmit and receive data in the 100 MHz bandwidth part according to the instructions of the base station.

In the method for setting the bandwidth part, terminals before RRC connection (Connected) can receive setting information on the initial bandwidth part (Initial Bandwidth Part) through a Master Information Block (MIB) in an initial access step. More specifically, the terminal is a control region (Control Resource Set, CORESET) can be set. The bandwidth of the control region set by the MIB may be regarded as an initial bandwidth portion, and the UE may receive a physical downlink shared channel (PDSCH) through which the SIB is transmitted through the initial bandwidth portion set. The initial bandwidth portion may be used for other system information (Other System Information, OSI), paging, and random access in addition to the purpose of receiving the SIB.

[Bandwidth Part (BWP) change]

When one or more bandwidth parts are configured for the terminal, the base station may instruct the terminal to change (or switch, transition) the bandwidth part using a Bandwidth Part Indicator field in the DCI. . For example, in FIG. 3, when the currently active bandwidth part of the terminal is bandwidth part #1 301, the base station may instruct the terminal with the bandwidth part #2 302 as a bandwidth part indicator in the DCI, and the terminal receives The bandwidth part change can be performed with the bandwidth part #2 302 indicated by the bandwidth part indicator in the DCI.

As described above, since the DCI-based bandwidth part change can be indicated by the DCI that schedules the PDSCH or PUSCH, when the UE receives the bandwidth part change request, the PDSCH or PUSCH scheduled by the corresponding DCI is grouped in the changed bandwidth part. It must be possible to receive or transmit without To this end, the standard stipulates a requirement for a delay time (T _BWP ) required when changing a bandwidth part, and may be defined, for example, as follows.

The requirement for the bandwidth portion change delay time may support type 1 or type 2 according to the capability of the terminal. The terminal may report the supportable bandwidth partial delay time type to the base station.

According to the above-mentioned requirement for the bandwidth portion change delay time, when the terminal receives the DCI including the bandwidth portion change indicator in slot n, the terminal changes to the new bandwidth portion indicated by the bandwidth portion change indicator in slot n+ It can be completed at a time no later than T _BWP , and transmission and reception for a data channel scheduled by the corresponding DCI can be performed in the changed new bandwidth part. When the base station wants to schedule the data channel with a new bandwidth part, it can determine the time domain resource allocation for the data channel in consideration of the bandwidth part change delay time (T _BWP ) of the terminal. That is, when scheduling a data channel with a new bandwidth part, in the method of determining time domain resource allocation for the data channel, the base station may schedule the corresponding data channel after the delay time for changing the bandwidth part. Accordingly, the terminal may not expect that the DCI indicating the bandwidth portion change indicates a slot offset value (K0 or K2) smaller than the bandwidth portion change delay time (T _BWP ).

If the terminal receives a DCI (for example, DCI format 1_1 or 0_1) indicating a change in bandwidth portion, the terminal receives the PDCCH including the DCI from the third symbol of the received slot, the time domain resource allocation indicator field in the corresponding DCI No transmission or reception may be performed during a time period corresponding to the start point of the slot indicated by the slot offset value (K0 or K2) indicated by . For example, if the terminal receives a DCI indicating a bandwidth portion change in slot n, and the slot offset value indicated by the corresponding DCI is K, the terminal moves from the third symbol of slot n to the previous symbol of slot n+K (i.e., the slot No transmission or reception may be performed until the last symbol of n+K-1).

[How to set transmission/reception parameters for each bandwidth part (BWP)]

Next, a method of setting parameters related to transmission and reception for each bandwidth part in 5G will be described.

The terminal may receive one or a plurality of bandwidth parts set from the base station, and parameters to be used for transmission and reception (eg, uplink data channel and control channel related setting information) may be additionally set for each set bandwidth part. For example, in FIG. 3, when the terminal is set to bandwidth part #1 (301) and bandwidth part #2 (302), the terminal can be set to transmit/receive parameter #1 for bandwidth part #1 (301), For the bandwidth part #2 (302), transmission/reception parameter #2 can be set. When bandwidth part #1 (301) is activated, the terminal can transmit/receive with the base station based on transmit/receive parameter #1, and when bandwidth part #2 (302) is activated, based on transmit/receive parameter #2. It can perform transmission and reception with the base station.

More specifically, the following parameters may be set from the base station to the terminal.

First, for the uplink bandwidth part, the following information may be set.

According to the above table, the terminal receives cell-specific (or cell common or common) transmission related parameters (e.g., Random Access Channel (RACH), Physical Uplink Control Channel (PUCCH) from the base station) ), uplink data channel (Physical Uplink Shared Channel) related parameters) can be set (corresponding to BWP-UplinkCommon). In addition, the UE receives UE-specific (or dedicated) transmission-related parameters (eg, PUCCH, PUSCH, unacknowledged-based uplink transmission (Configured Grant PUSCH), Sounding Reference Signal (SRS)) from the base station. ) related parameters) can be set (corresponding to BWP-UplinkDedicated).

Next, for the downlink bandwidth part, the following information can be set.

According to the above table, the terminal receives cell-specific (or cell common or common) parameters related to reception from the base station (eg, Physical Downlink Control Channel (PDCCH), Downlink Data Channel (Physical Downlink Shared Channel)) ) related parameters) can be set (corresponding to BWP-DownlinkCommon). In addition, the UE receives UE-specific (or dedicated) parameters related to reception from the base station (e.g., PDCCH, PDSCH, unacknowledgment-based downlink data transmission (Semi-persistent Scheduled PDSCH), radio link monitoring (Radio Link Monitoring) ; RLM) related parameters) can be set (corresponding to BWP-UplinkDedicated).

[SS/PBCH block]

Next, a Synchronization Signal (SS)/PBCH block in 5G will be described.

The SS/PBCH block may refer to a physical layer channel block composed of a Primary SS (PSS), a Secondary SS (SSS), and a PBCH. Specifically, it is as follows.

- PSS: This is a signal that is a standard for downlink time/frequency synchronization and provides some information of cell ID.

- SSS: serves as a standard for downlink time/frequency synchronization, and provides remaining cell ID information not provided by PSS. Additionally, it can serve as a reference signal for demodulation of PBCH.

- PBCH: Provides essential system information necessary for transmitting and receiving the data channel and control channel of the terminal. Essential system information may include search space-related control information indicating radio resource mapping information of a control channel, scheduling control information for a separate data channel through which system information is transmitted, and the like.

- SS/PBCH block: The SS/PBCH block consists of a combination of PSS, SSS, and PBCH. One or a plurality of SS/PBCH blocks may be transmitted within 5 ms, and each SS/PBCH block to be transmitted may be distinguished by an index.

The UE can detect the PSS and SSS in the initial access stage and decode the PBCH. The MIB can be obtained from the PBCH, and a control resource set (CORESET) #0 (which may correspond to a control region having a control region index of 0) can be set therefrom. The UE may perform monitoring for control region #0, assuming that the selected SS/PBCH block and demodulation reference signal (DMRS) transmitted in control region #0 are quasi co-located (QCL). The terminal may receive system information through downlink control information transmitted in control region #0. The terminal may obtain RACH (Random Access Channel) related setting information required for initial access from the received system information. The terminal may transmit a physical RACH (PRACH) to the base station in consideration of the selected SS/PBCH index, and the base station receiving the PRACH may obtain information on the SS/PBCH block index selected by the terminal. The base station can know that the terminal has selected a certain block among the SS/PBCH blocks and monitors the control region #0 related thereto.

[PDCCH: DCI related]

Next, downlink control information (DCI) in the 5G system will be described in detail.

Scheduling information for uplink data (or physical uplink shared channel (PUSCH)) or downlink data (or physical downlink shared channel (PDSCH)) in a 5G system is provided through DCI It is transmitted from the base station to the terminal. The UE may monitor the DCI format for fallback and the DCI format for non-fallback with respect to PUSCH or PDSCH. The contingency DCI format may be composed of a fixed field predefined between the base station and the terminal, and the non-preparation DCI format may include a configurable field.

DCI may be transmitted through a physical downlink control channel (PDCCH) through channel coding and modulation processes. A Cyclic Redundancy Check (CRC) is attached to the DCI message payload, and the CRC may be scrambled with a Radio Network Temporary Identifier (RNTI) corresponding to the identity of the UE. Different RNTIs may be used according to the purpose of the DCI message, eg, UE-specific data transmission, power control command, or random access response. That is, the RNTI is not transmitted explicitly but is included in the CRC calculation process and transmitted. Upon receiving the DCI message transmitted on the PDCCH, the UE checks the CRC using the allocated RNTI, and if the CRC check result is correct, the UE can know that the corresponding message has been transmitted to the UE.

For example, DCI scheduling a PDSCH for system information (SI) may be scrambled with SI-RNTI. A DCI scheduling a PDSCH for a Random Access Response (RAR) message may be scrambled with RA-RNTI. A DCI scheduling a PDSCH for a paging message may be scrambled with a P-RNTI. DCI notifying SFI (Slot Format Indicator) may be scrambled with SFI-RNTI. DCI notifying TPC (Transmit Power Control) can be scrambled with TPC-RNTI. DCI scheduling UE-specific PDSCH or PUSCH may be scrambled with C-RNTI (Cell RNTI).

DCI format 0_0 can be used as a fallback DCI for scheduling PUSCH, and in this case, CRC can be scrambled with C-RNTI. DCI format 0_0 in which CRC is scrambled with C-RNTI may include, for example, the following information.

DCI format 0_1 can be used as a non-backup DCI for scheduling PUSCH, and in this case, CRC can be scrambled with C-RNTI. DCI format 0_1 in which CRC is scrambled with C-RNTI may include, for example, the following information.

DCI format 1_0 can be used as a fallback DCI for scheduling PDSCH, and in this case, CRC can be scrambled with C-RNTI. DCI format 1_0 in which CRC is scrambled with C-RNTI may include, for example, the following information.

DCI format 1_1 can be used as a non-backup DCI for scheduling PDSCH, and in this case, CRC can be scrambled with C-RNTI. DCI format 1_1 in which CRC is scrambled with C-RNTI may include, for example, the following information.

Hereinafter, a method of allocating time domain resources for a data channel in a 5G communication system will be described.

The base station transmits a table for time domain resource allocation information for a downlink shared channel (PDSCH) and a physical uplink shared channel (PUSCH) to the terminal by higher layer signaling (eg, RRC signaling). For PDSCH, a table consisting of maxNrofDL-Allocations = 16 entries can be set, and for PUSCH, a table consisting of maxNrofUL-Allocations = 16 entries can be set. The time domain resource allocation information includes, for example, PDCCH-to-PDSCH slot timing (corresponding to a time interval in units of slots between the time of receiving the PDCCH and the time of transmitting the PDSCH scheduled by the received PDCCH, denoted as K0), or PDCCH-to-PUSCH slot timing (corresponding to the time interval in units of slots between the time when the PDCCH is received and the time when the PUSCH scheduled by the received PDCCH is transmitted, denoted as K2), PDSCH or PUSCH scheduled within the slot Information on the position and length of the start symbol, mapping type of PDSCH or PUSCH, etc. may be included. For example, information such as the table below may be notified from the base station to the terminal.

The base station may notify the terminal of one of the table entries for the time domain resource allocation information to the terminal through L1 signaling (eg, DCI) (eg, the 'time domain resource allocation' field in the DCI may be indicated). can). The terminal may obtain time domain resource allocation information for the PDSCH or PUSCH based on the DCI received from the base station.

[PDCCH: CORESET, REG, CCE, Search Space]

In the following, a downlink control channel in a 5G communication system will be described in more detail with reference to the drawings.

4 is a diagram showing an example of a control region (Control Resource Set, CORESET) in which a downlink control channel is transmitted in a 5G wireless communication system. 4 shows a UE bandwidth part 410 on the frequency axis and two control regions (control region # 1 401 and control region # 2 402) within 1 slot 420 on the time axis. Shows an example of what has been done. The

control regions

401 and 402 may be set to a specific frequency resource 403 within the entire terminal bandwidth portion 410 on the frequency axis. The time axis may be set to one or a plurality of OFDM symbols, and this may be defined as a control region length (Control Resource Set Duration, 404). Referring to the illustrated example of FIG. 4 , control region #1 (401) is set to a control region length of 2 symbols, and control region #2 (402) is set to a control region length of 1 symbol.

The control region in the aforementioned 5G may be set by the base station to the terminal through higher layer signaling (eg, system information, master information block (MIB), radio resource control (RRC) signaling). Setting the control region to the terminal means providing information such as a control region identifier (Identity), a frequency location of the control region, and a symbol length of the control region. For example, it may include the following information.

In Table 12, tci-StatesPDCCH (simply named TCI (Transmission Configuration Indication) state) configuration information is one or more SS (Synchronization Signal) in a Quasi Co Located (QCL) relationship with DMRS transmitted in the corresponding control area /PBCH (Physical Broadcast Channel) block index or CSI-RS (Channel State Information Reference Signal) index information may be included.

5 is a diagram showing an example of basic units of time and frequency resources constituting a downlink control channel that can be used in 5G. According to FIG. 5, the basic unit of time and frequency resources constituting the control channel can be referred to as a REG (Resource Element Group, 503), and the REG 503 is 1 OFDM symbol 501 on the time axis and 1 PRB on the frequency axis. (Physical Resource Block, 502), that is, it can be defined as 12 subcarriers. The base station may configure a downlink control channel allocation unit by concatenating the REGs 503.

As shown in FIG. 5, when a basic unit to which a downlink control channel is allocated in 5G is a Control Channel Element (CCE) 504, one CCE 504 may be composed of a plurality of REGs 503. Taking the REG 503 shown in FIG. 5 as an example, the REG 503 may consist of 12 REs, and if 1 CCE 504 consists of 6 REGs 503, 1 CCE 504 may consist of 72 REs. When a downlink control region is set, the corresponding region can be composed of a plurality of CCEs 504, and a specific downlink control channel is divided into one or a plurality of CCEs 504 according to an aggregation level (AL) in the control region. It can be mapped and transmitted. The CCEs 504 in the control area are identified by numbers, and at this time, the numbers of the CCEs 504 may be assigned according to a logical mapping method.

The basic unit of the downlink control channel shown in FIG. 5, that is, the REG 503, may include both REs to which DCI is mapped and a region to which the DMRS 505, which is a reference signal for decoding them, is mapped. As shown in FIG. 5, three DMRSs 505 may be transmitted within one REG 503. The number of CCEs required to transmit the PDCCH can be 1, 2, 4, 8, or 16 depending on the aggregation level (AL), and the different numbers of CCEs can be used for link adaptation of the downlink control channel. can be used to implement For example, when AL=L, one downlink control channel can be transmitted through L CCEs. A UE needs to detect a signal without knowing information about a downlink control channel. A search space representing a set of CCEs is defined for blind decoding. The search space is a set of downlink control channel candidates consisting of CCEs that the UE should attempt to decode on a given aggregation level, and various aggregations that make one group with 1, 2, 4, 8, and 16 CCEs Since there are levels, the terminal can have a plurality of search spaces. A search space set may be defined as a set of search spaces at all set aggregation levels.

The search space can be classified into a common search space and a UE-specific search space. A certain group of terminals or all terminals can search the common search space of the PDCCH in order to receive cell-common control information such as dynamic scheduling for system information or a paging message. For example, PDSCH scheduling allocation information for SIB transmission including cell operator information may be received by examining the common search space of the PDCCH. In the case of a common search space, since a certain group of terminals or all terminals must receive the PDCCH, it can be defined as a set of pre-promised CCEs. Scheduling assignment information for the UE-specific PDSCH or PUSCH may be received by examining the UE-specific search space of the PDCCH. The UE-specific search space may be defined UE-specifically as a function of the identity of the UE and various system parameters.

In 5G, a parameter for a search space for a PDCCH may be configured from a base station to a terminal through higher layer signaling (eg, SIB, MIB, RRC signaling). For example, the base station includes the number of PDCCH candidate groups at each aggregation level L, a monitoring period for the search space, a monitoring occasion in symbol units within a slot for the search space, a search space type (common search space or UE-specific search space), A combination of a DCI format and an RNTI to be monitored in the corresponding search space, a control region index to be monitored in the search space, and the like may be set to the terminal. For example, it may include the following information.

According to the setting information, the base station may set one or a plurality of search space sets for the terminal. According to some embodiments, the base station may set search space set 1 and search space set 2 to the terminal, set DCI format A scrambled with X-RNTI in search space set 1 to be monitored in a common search space, and search DCI format B scrambled with Y-RNTI in space set 2 can be configured to be monitored in a UE-specific search space.

According to the setting information, one or a plurality of search space sets may exist in a common search space or a terminal-specific search space. For example, search space set #1 and search space set #2 may be set as common search spaces, and search space set #3 and search space set #4 may be set as terminal-specific search spaces.

In the common search space, a combination of the following DCI format and RNTI can be monitored. Of course, it is not limited to the following examples.

- DCI format 0_0/1_0 with CRC scrambled by C-RNTI, CS-RNTI, SP-CSI-RNTI, RA-RNTI, TC-RNTI, P-RNTI, SI-RNTI

- DCI format 2_0 with CRC scrambled by SFI-RNTI

- DCI format 2_1 with CRC scrambled by INT-RNTI

- DCI format 2_2 with CRC scrambled by TPC-PUSCH-RNTI, TPC-PUCCH-RNTI

- DCI format 2_3 with CRC scrambled by TPC-SRS-RNTI

In the UE-specific search space, a combination of the following DCI format and RNTI may be monitored. Of course, it is not limited to the following examples.

- DCI format 0_0/1_0 with CRC scrambled by C-RNTI, CS-RNTI, TC-RNTI

- DCI format 1_0/1_1 with CRC scrambled by C-RNTI, CS-RNTI, TC-RNTI

The specified RNTIs may follow the following definitions and uses.

C-RNTI (Cell RNTI): Use of UE-specific PDSCH scheduling

TC-RNTI (Temporary Cell RNTI): Use for UE-specific PDSCH scheduling

CS-RNTI (Configured Scheduling RNTI): Use of semi-statically configured UE-specific PDSCH scheduling

RA-RNTI (Random Access RNTI): PDSCH scheduling in random access phase

P-RNTI (Paging RNTI): PDSCH scheduling purpose through which paging is transmitted

SI-RNTI (System Information RNTI): PDSCH scheduling purpose for transmitting system information

INT-RNTI (Interruption RNTI): used to inform whether pucturing for PDSCH

TPC-PUSCH-RNTI (Transmit Power Control for PUSCH RNTI): Used to indicate power control command for PUSCH

TPC-PUCCH-RNTI (Transmit Power Control for PUCCH RNTI): Use to indicate power control command for PUCCH

TPC-SRS-RNTI (Transmit Power Control for SRS RNTI): Used to indicate power control command for SRS

The aforementioned specified DCI formats may follow the definition below.

In 5G, the search space of the aggregation level L in the control region p and the search space set s can be expressed as Equation 1 below.

- L: aggregation level

-

: Carrier index

-

: Total number of CCEs present in the control area p

-

: slot index

-

: Number of PDCCH candidates at aggregation level L

-

= 0,...,

: PDCCH candidate group index of aggregation level L

- i=0,...,L-1

-

,

, and D=65537.

-

: terminal identifier

The value may correspond to 0 in the case of a common search space.

In the case of a UE-specific search space, the value may correspond to a value that changes according to the identity of the UE (C-RNTI or ID set for the UE by the base station) and the time index.

In 5G, as a plurality of search space sets can be set with different parameters (eg, parameters in Table 13), the set of search space sets monitored by the terminal at each point in time may be different. For example, if search space set #1 is set to an X-slot period and search space set #2 is set to a Y-slot period and X and Y are different, the terminal searches search space set #1 and search space set #1 in a specific slot. All space set #2 can be monitored, and one of search space set #1 and search space set #2 can be monitored in a specific slot.

[PDCCH: UE Capability Report]

Slot positions in which the above-described common search space and the terminal-specific search space are located are indicated by the monitoringSymbolsWitninSlot parameter in Table 13, and symbol positions in slots are indicated as a bitmap through the monitoringSymbolsWithinSlot parameter in Table 13. Meanwhile, a symbol position within a slot in which search space monitoring is possible by the terminal may be reported to the base station through the following UE capabilities.

- Terminal capability 1 (hereinafter referred to as FG 3-1). As shown in Table 15-1 below, when there is one MO monitoring occasion (MO) for the type 1 and type 3 common search space or the UE-specific search space in the slot, the corresponding MO location is the slot It means the ability to monitor the corresponding MO when located within the first 3 symbols within. This UE capability is a mandatory capability that all UEs supporting NR must support, and whether or not this capability is supported is not explicitly reported to the base station.

[Table 15-1]

- Terminal capability 2 (hereafter referred to as FG 3-2). As shown in Table 15-2 below, when there is one monitoring occasion (MO) in a slot for a common search space or a UE-specific search space, regardless of the start symbol position of the corresponding MO, the UE capability It means the ability to monitor. This terminal capability can be selectively supported by the terminal (optional), and whether or not this capability is supported is explicitly reported to the base station.

[Table 15-2]

- Terminal capability 3 (hereafter referred to as FGs 3-5, 3-5a, 3-5b). As shown in Table 15-3 below, the UE capability indicates a pattern of MOs that can be monitored by the UE when a plurality of monitoring occasions (MOs) exist in a slot for a common search space or a UE-specific search space. do. The above-described pattern consists of a starting inter-symbol interval X between different MOs and a maximum symbol length Y for one MO. The combination of (X,Y) supported by the terminal may be one or a plurality of {(2,2), (4,3), (7,3)}. This terminal capability can be selectively supported by the terminal (optional), and whether or not this capability is supported and the above-described (X,Y) combination are explicitly reported to the base station.

[Table 15-3]

The UE may report whether or not to support UE capability 2 and/or UE capability 3 and related parameters to the BS. The base station may perform time axis resource allocation for a common search space and a terminal-specific search space based on the reported terminal capabilities. When allocating the resource, the base station may prevent the terminal from locating the MO in a position where monitoring is impossible.

[PDCCH: BD/CCE limit]

When a plurality of search space sets are configured for a terminal, the following conditions may be considered in a method for determining a search space set to be monitored by a terminal.

If the UE has set the value of monitoringCapabilityConfig-r16, which is upper layer signaling, to r15monitoringcapability, the UE can monitor the number of PDCCH candidate groups that can be monitored and the total search space (here, the total search space is the number corresponding to the union area of a plurality of search space sets). The maximum value for the number of CCEs constituting the entire CCE set) is defined for each slot, and if the value of monitoringCapabilityConfig-r16 is set to r16monitoringcapability, the UE determines the number of PDCCH candidates that can be monitored and the total search space ( Here, the total search space means the entire set of CCEs corresponding to the union area of a plurality of search space sets). The maximum value for the number of CCEs constituting each span is defined.

[Condition 1: Limit the maximum number of PDCCH candidates]

As described above, when M ^μ , the maximum number of PDCCH candidates that can be monitored by the UE according to the setting value of higher layer signaling, is defined on a slot-by-slot basis in a cell set to a subcarrier interval of 15 2 ^μ kHz, Table 16-1 and can follow Table 16-2 below when defined based on span.

[Table 16-1]

[Table 16-2]

[Condition 2: Limit the maximum number of CCEs]

As described above, C ^μ , the maximum number of CCEs constituting the entire search space (here, the entire search space means the entire set of CCEs corresponding to the union area of a plurality of search space sets) according to the setting value of higher layer signaling, is In a cell with a carrier interval of 15 2 ^μ kHz, when defined on a slot basis, Table 16-3 follows, and when defined on a span basis, Table 16-4 below may be followed.

[Table 16-3]

[Table 16-4]

For convenience of explanation, a situation in which both

conditions

1 and 2 are satisfied at a specific point in time is defined as “condition A”. Accordingly, not satisfying condition A may mean not satisfying at least one of

conditions

1 and 2 above.

[PDCCH: Overbooking]

Depending on the setting of search space sets of the base station, a case in which condition A is not satisfied may occur at a specific point in time. When condition A is not satisfied at a specific time point, the terminal may select and monitor only a part of search space sets configured to satisfy condition A at that time point, and the base station may transmit a PDCCH to the selected search space set.

As a method of selecting some search spaces from the set of all set search spaces, the following method may be followed.

If condition A for the PDCCH is not satisfied at a specific time point (slot), the UE (or the base station) selects a search space set whose search space type is set to a common search space among search space sets existing at that time point. - Priority can be given to a search space set set as a specific search space.

When all search space sets set as the common search space are selected (that is, when condition A is satisfied even after all search spaces set as the common search space are selected), the terminal (or the base station) terminal-specific search space Search space sets set to can be selected. In this case, when there are a plurality of search space sets set as the terminal-specific search space, a search space set having a lower search space set index may have a higher priority. In consideration of priority, UE-specific search space sets may be selected within a range satisfying condition A.

[Regarding device capability reporting]

In LTE and NR, the terminal may perform a procedure for reporting the capability supported by the terminal to the corresponding base station while connected to the serving base station. In the description below, this is referred to as a UE capability report.

The base station may transmit a UE capability inquiry message requesting a capability report to a UE in a connected state. The message may include a UE capability request for each radio access technology (RAT) type of the base station. The request for each RAT type may include supported frequency band combination information. In addition, in the case of the terminal capability inquiry message, UE capabilities for each RAT type may be requested through one RRC message container transmitted by the base station, or the base station sends a terminal capability inquiry message including a terminal capability request for each RAT type. It can be included multiple times and delivered to the terminal. That is, in one message, the UE capability inquiry is repeated multiple times, and the UE can construct and report a corresponding UE capability information message multiple times. In the next-generation mobile communication system, a UE capability request for MR-DC (Multi-RAT dual connectivity) including NR, LTE, and EN-DC (E-UTRA-NR dual connectivity) can be requested. In addition, although the terminal capability inquiry message is generally initially transmitted after the terminal connects to the base station, the base station may request it under any condition when necessary.

In the above step, the terminal receiving the UE capability report request from the base station configures the terminal capability according to the RAT type and band information requested from the base station. Below is a summary of how the UE configures UE capabilities in the NR system.

1. If the terminal receives a list of LTE and/or NR bands from the base station as a UE capability request, the terminal configures a band combination (BC) for EN-DC and NR stand alone (SA). That is, BC candidate lists for EN-DC and NR SA are configured based on the bands requested to the base station through FreqBandList. In addition, bands have priorities in the order described in FreqBandList.

2. If the base station sets the "eutra-nr-only" flag or the "eutra" flag to request UE capability reporting, the terminal completely removes those for NR SA BCs from the configured BC candidate list. This operation may occur only when the LTE base station (eNB) requests the "eutra" capability.

3. After that, the terminal removes fallback BCs from the candidate list of BCs configured in the above step. Here, the fallback BC means a BC that can be obtained by removing a band corresponding to at least one SCell from any BC, and since the BC before removing the band corresponding to at least one SCell can already cover the fallback BC, can be omitted. This step also applies to MR-DC, ie LTE bands as well. The remaining BCs after this step are the final "candidate BC list".

4. The terminal selects BCs to be reported by selecting BCs suitable for the requested RAT type from the final "candidate BC list". In this step, the terminal configures the supportedBandCombinationList in a predetermined order. That is, the terminal configures the BC and UE capabilities to be reported according to the order of the preset rat-Type. (nr -> eutra-nr -> eutra). In addition, featureSetCombination is configured for the configured supportedBandCombinationList, and a list of "candidate feature set combination" is configured in the candidate BC list from which the list for fallback BC (including capabilities of the same or lower level) is removed. The above "candidate feature set combination" includes both feature set combinations for NR and EUTRA-NR BC, and can be obtained from the feature set combination of the UE-NR-Capabilities and UE-MRDC-Capabilities containers.

5. In addition, if the requested rat Type is eutra-nr and has an effect, featureSetCombinations is included in both containers of UE-MRDC-Capabilities and UE-NR-Capabilities. However, the feature set of NR includes only UE-NR-Capabilities.

After the terminal capabilities are configured, the terminal transmits a terminal capability information message including the terminal capabilities to the base station. Based on the terminal capabilities received from the terminal, the base station then performs appropriate scheduling and transmission/reception management for the corresponding terminal.

[Related to TDD DL-UL setting]

6 is a diagram illustrating an example of a method for configuring uplink and downlink resources in a 5G wireless communication system according to an embodiment of the present disclosure.

Referring to FIG. 6 , a slot 601 may include 14 symbols 602 . Uplink-downlink configuration of symbols/slots in the 5G communication system can be set in three steps. First, uplink-downlink of real balls/slots can be set semi-statically in symbol units through cell specific configuration information 610 through system information. Specifically, cell-specific uplink-downlink configuration information through system information may include uplink-downlink pattern information and reference subcarrier information. Uplink-downlink pattern information includes a pattern period (periodicity, 603), the number of consecutive downlink slots from the start of each pattern (611), the number of symbols in the next slot (612), and consecutive uplink slots from the end of the pattern. The number 613 and the number of symbols 614 of the next slot may be indicated. At this time, slots and symbols not indicated as uplink and downlink may be determined as flexible slots/symbols.

Second, through user characteristic configuration information through dedicated upper layer signaling, flexible slots or

slots

621 and 622 including flexible symbols are the number of consecutive downlink symbols from the start symbol of each slot. (623, 625) and the number of consecutive uplink symbols (624, 626) from the end of the slot, or may be indicated as downlink in all slots or uplink in all slots.

Also, finally, in order to dynamically change downlink signal transmission and uplink signal transmission intervals, symbols indicated as flexible symbols in each slot (ie, symbols not indicated as downlink and uplink) ) may indicate whether each is a downlink symbol, an uplink symbol, or a flexible symbol through slot format indicators (SFI, 631, 632) included in the downlink control channel. there is. As for the slot format indicator, one index can be selected from [Table 17] in which an uplink-downlink configuration of 14 symbols in one slot is set as shown in the following table.

[Table 17]

[Related to XDD DL-UL settings]

5G mobile communication service introduced additional coverage expansion technology compared to LTE communication service, but the actual coverage of 5G mobile communication service can use a TDD system suitable for services with a high proportion of downlink traffic. In addition, as the center frequency increases to increase the frequency band, the coverage of the base station and the terminal decreases, so coverage enhancement is a key requirement for 5G mobile communication services. In particular, in order to support a service in which the transmit power of the terminal is generally lower than the transmit power of the base station and the proportion of downlink traffic is high, and because the proportion of downlink is higher than that of uplink in the time domain, the coverage improvement of the uplink channel is 5G It is a core requirement of mobile communication service. As a method of physically improving the coverage of an uplink channel between a base station and a terminal, there may be a method of increasing a time resource of an uplink channel, lowering a center frequency, or increasing transmit power of a terminal. However, changing the frequency may have limitations because the frequency band is determined for each network operator. In addition, increasing the maximum transmission power of the terminal may have restrictions because the maximum value is determined to reduce interference, that is, the maximum transmission power of the terminal is determined by regulation.

Therefore, in order to improve the coverage of the base station and the terminal, uplink and downlink resources can be divided in the frequency domain as in the FDD system, rather than dividing the ratio in the time domain according to the ratio of uplink and downlink traffic in the TDD system. . In one embodiment, systems that can flexibly divide uplink resources and downlink resources in the time domain and frequency domain include an XDD system, a flexible TDD system, a hybrid TDD system, a TDD-FDD system, a hybrid TDD-FDD system, and a subband full It may be referred to as a duplex system, a full duplex system, and the like, and for convenience of description, an XDD system will be described in the present disclosure. According to one embodiment, X in XDD may mean time or frequency.

7 is a diagram illustrating an uplink-downlink configuration of an XDD system in which uplink and downlink resources are flexibly divided in a time domain and a frequency domain according to an embodiment of the present disclosure.

Referring to FIG. 7, the uplink-downlink configuration 700 of the entire XDD system from the point of view of the base station is each symbol or slot 702 according to the traffic ratio of uplink and downlink with respect to the entire frequency band 701 Each resource can be configured to be flexibly allocated. In this case, a guard band 705 may be allocated between the downlink resource 703 and the uplink resource 704 in the frequency domain. The guard band 705 reduces interference to reception of an uplink channel or signal due to out-of-band emission generated when a base station transmits a downlink channel or signal in a downlink resource 703. can be assigned as a way to

Terminal 1 710 and Terminal 2 720, which generally have more downlink traffic than uplink traffic, can be allocated more downlink resources compared to uplink resources by setting the base station. For example, a downlink to uplink resource ratio may be 4:1 in the time domain. Terminal 3 730, which operates at the cell edge and lacks uplink coverage, can be allocated a smaller number of downlink resources compared to uplink resources by setting the base station. For example, a downlink to uplink resource ratio may be 1:4 in the time domain. In this way, to Terminal 4 740, which operates relatively in the cell center and has a lot of downlink traffic, more downlink resources are allocated in the time domain to increase downlink transmission efficiency, and operates relatively at the cell edge and lacks uplink coverage. More uplink resources may be allocated to UEs in the time domain.

8 shows an example of an uplink-downlink configuration method in an XDD system.

In the XDD system, necessary resources can be set according to the uplink-downlink configuration configuration according to the situation of the terminal. For example, referring to FIG. 801, an uplink-downlink configuration can be set in the frequency domain and time domain through different uplink-downlink settings for each frequency band part (BWP). The base station and the terminal can basically change frequency domain resources through BWP change, and can change uplink-downlink settings in the frequency domain and time domain by changing time domain resources through uplink-downlink configuration associated with BWP. there is. As another example, referring to FIG. 811, an uplink-downlink configuration configured from a base station may be configured by dividing the frequency axis for one or more symbols/slots. That is, 2D uplink-downlink configuration information can be set, and resources for symbols/slots can be set using a 2D slot format indicator (SFI). As another example, referring to FIG. 821, uplink-downlink configuration may be performed in combination with each other instead of uplink-downlink configuration in the time domain for each BWP. As the BWP is changed, the uplink-downlink configuration of the time domain is not changed together, but the uplink-downlink configuration of the time domain can be changed separately from the BWP.

[Bandwidth Part (BWP) Change Delay Time]

In 5G, a terminal may receive one or a plurality of bandwidth parts set from a base station, and may receive setting information of various system parameters necessary for uplink transmission or downlink reception for each set bandwidth part. The terminal may receive a bandwidth part activation setting or indicator from the base station, and the terminal may perform transmission/reception operations with the base station based on system parameters set in the activated bandwidth part.

Since parameters related to transmission and reception can be set for each bandwidth part, the terminal can change the parameters related to transmission and reception by changing the bandwidth part. For example, if the terminal has transmission/reception parameter #1 set in bandwidth part #1 and transmission/reception parameter #2 is set in bandwidth part #2, the terminal performs a change from bandwidth part #1 to bandwidth part #2 If so, this may involve changing from transmit/receive parameter #1 to transmit/receive parameter #2. As such, the terminal may perform a transmission/reception parameter change through a bandwidth part change. The base station may instruct the terminal to change the bandwidth part for various purposes, for example, the purpose of reducing power consumption of the terminal, the purpose of extending coverage, the purpose of reducing latency, and the purpose of improving throughput. It is possible to perform transmission and reception with the base station with transmission and reception parameters optimized for the purpose.

In a conventional TDD system, even if a UE receives uplink transmission scheduling in a process of receiving a downlink signal, the UE may have to wait for an upcoming uplink slot or change to a bandwidth part with many uplink resources. If the bandwidth part is changed to change the setting information of the transmission/reception parameters described above, a delay time according to the change of the bandwidth part is basically accompanied. For example, the bandwidth part change delay time (T _BWP ) described in Table 3 may be requested. The delay time for changing the bandwidth part may include DCI decoding time, RF (Radio Frequency) and BB (Baseband) parameter modification time (including center frequency adjustment process), time to apply the new parameter indicated, etc. , but not limited to the above description. Accordingly, an operation of changing transmission/reception parameter settings of the terminal may be inefficient, and as a result, uplink transmission of the terminal may be delayed or coverage performance may deteriorate.

Meanwhile, the terminal may change from a downlink symbol to an uplink symbol based on transmission/reception parameter information set through higher signaling (eg, RRC Reconfiguration message) from the base station (hereinafter, downlink symbol -> uplink symbol switching). In general, when performing downlink symbol->uplink symbol switching, different guard periods may be required according to the size of a cell area in order to reduce interference between two links. For example, if one symbol is about 33 μs based on a 30 kHz subcarrier spacing and 2 or 4 symbols are required as a guard time, a guard time of 66 μs or 198 μs may be required. On the other hand, according to Table 3, the terminal received an instruction to change from the downlink of bandwidth part # 1 to the uplink of bandwidth part # 2 by higher signaling (eg, RRC Reconfiguration message) or downlink control indicator (DCI) from the base station In this case, a bandwidth part change delay time of 1 ms for Type 1 and 2.5 ms for Type 2 based on the 30 kHz subcarrier interval may be required. In the above example, the bandwidth part change delay time may be about 5 to 40 times longer than the downlink symbol -> uplink symbol protection time, which may cause uplink transmission delay and degradation of uplink coverage performance.

The bandwidth part change delay time may require a relatively long time or a short time depending on how much a parameter among parameters set in the bandwidth part is changed. For example, if the terminal changes the bandwidth part, the location of the bandwidth part and the center frequency, bandwidth or numerology of the bandwidth part (for example, Cyclic Prefix length or subcarrier When an interval (subcarrier spacing; SCS, etc.) is changed, this may require a relatively long bandwidth part change delay time from the terminal. On the other hand, when only other transmit/receive related parameters are changed while the center frequency and bandwidth or numerology of the bandwidth part remain the same, only a relatively short delay time for changing the bandwidth part of the terminal may be required. Likewise, different guard times may be applied according to the difference between the downlink symbol->uplink symbol guard time and the degree of sharing of bandwidth resources and the difference between the center frequencies of the downlink resource and the uplink resource.

Hereinafter, a method for reducing a delay time required for BWP change will be described through an embodiment proposed in the present disclosure.

The first embodiment describes a method of defining UE capability information for BWP switching and reporting the information by the UE to the base station. For example, the BWP switching information may include whether or not the UE supports BWP switching, BWP switching type information, and/or the maximum number of changeable BWPs.

9 is a diagram illustrating UE capability report signaling according to an embodiment of the present disclosure.

Referring to FIG. 9 , a base station 901 may request a terminal capability report from a terminal 902 (905), and the terminal 902 may report terminal capability information to the base station (910) at the request of the base station. there is. The corresponding UE capability information may include capability information related to BWP switching. A method of configuring capability information related to the BWP switching may be as follows.

For example, the terminal may report to the base station whether or not the BWP switching of the method proposed in the present disclosure is supported as capability information. If, a terminal that does not support BWP switching of the scheme proposed in this disclosure may operate according to the conventional BWP switching scheme.

[Table 18] and [Table 19] are examples of UE capability information according to an embodiment of the present disclosure.

Referring to the examples of [Table 18] and [Table 19], bwp-SwitchingDelay may mean a bandwidth part delay time type that can be supported according to the capabilities of the UE. For example, type 1 or type 2 may be reported as bwp-SwitchingDelay . Alternatively, a new type such as type 3 may be reported. A bandwidth part change delay time corresponding to each type may be predefined. In addition, maxNumber-bwp-Switching may mean the maximum number of bandwidth parts that the terminal can change from existing bandwidth parts. For example, if maxNumber-bwp-Switching is defined as 6, it may mean that the UE can change the BWP to one of up to 6 different bandwidth parts.

The names of the parameters described above are only examples, and are not limited to the names described in this embodiment.

[Table 18]

[Table 19]

The second embodiment proposes a method of reducing a delay time required for changing from a downlink bandwidth part to an uplink bandwidth part when a terminal receives a plurality of uplink bandwidth parts from a base station.

The plurality of uplink bandwidth parts configured by the terminal from the base station may include at least one upper uplink bandwidth part and at least one lower uplink bandwidth part. One of the at least one higher uplink bandwidth part may have the same center frequency as the downlink bandwidth part. Also, the lower uplink bandwidth part may refer to a bandwidth part having a smaller size than an upper uplink bandwidth part having the same center frequency as the downlink bandwidth part.

For example, a method of operating a lower uplink bandwidth part having the same center frequency as the upper uplink bandwidth part and having frequency resources overlapping with the upper uplink and downlink bandwidth parts may be considered.

When the terminal receives one downlink bandwidth part and a plurality of uplink bandwidth parts from the base station, the lower uplink bandwidth part has the same center frequency as the upper uplink bandwidth part and the frequency resources are all overlapped. It is possible to reduce the delay time required to change from the downlink bandwidth part to the uplink bandwidth part by operating.

10A and 10B are diagrams illustrating an example of setting a bandwidth part according to an embodiment of the present disclosure.

According to an embodiment of the present disclosure, a terminal may be configured with one downlink bandwidth part and a plurality of uplink bandwidth parts through higher layer signaling from a base station. 10A and 10B show an example in which downlink bandwidth part #1, uplink bandwidth part #1, uplink bandwidth part #1-1, and uplink bandwidth part #2 are configured.

Referring to FIG. 10A, a terminal receives one downlink bandwidth part #1 (1005a), two upper uplink bandwidth parts #1 and #2 (1010a, 1020a), and one lower uplink bandwidth part (1015a) from a base station. can be set. At this time, the lower uplink bandwidth part # 1-1 (1015a) may have the following characteristics:

- The lower uplink bandwidth part #1-1 (1015a) may be set to have the same center frequency as the downlink bandwidth part #1 (1005a) and the upper uplink bandwidth part #1 (1010a). And, the bandwidth size of the lower uplink bandwidth part #1-1 (1015a) may be formed within the downlink bandwidth part #1 (1005a) and the upper uplink bandwidth part #1 (1010a).

In the setting information of the lower uplink bandwidth part #1-1 (1015a), as part of the setting information of the upper uplink bandwidth part #1 (1010a), parameters related to transmission and reception (e.g., see Tables 2, 4, and 5) may be included in whole or in part.

While receiving a downlink signal through downlink bandwidth part #1 (1005a), the terminal may be instructed to change to a new uplink bandwidth part, for example, lower uplink bandwidth part #1-1 (1015a) through DCI. there is. The contents of the bandwidth part change indicator will be described in detail in the fourth embodiment.

Referring to FIG. 10B, while receiving a downlink signal in downlink bandwidth part #1 (1005b), the UE may be instructed to change to a lower uplink bandwidth part #1-1 (1015b) through DCI (1030b). . At this time, the remaining part of the previously set downlink bandwidth part # 1 may be deactivated (1025b), and downlink symbol -> uplink symbol protection time (ie, change/switching from downlink symbol to uplink symbol) After the guard time for) elapses, the lower uplink bandwidth #1-1 (1015b) may be activated.

When the UE changes from the downlink bandwidth part #1 (1005b) to the higher uplink bandwidth part #1 (1010b), the guard period required is the unit of μs. It may be shorter than the bandwidth part change delay time (BWP switching delay) in ms units required when changing to the bandwidth part # 2 (1020b).

When the UE changes from the downlink bandwidth part # 1 (1005b) to the lower uplink bandwidth part # 1-1 (1015b), a guard period in symbol units is required and / or downlink bandwidth part # 1 (1005b ) to the upper uplink bandwidth part # 1 (1010b), the same guard period as the required guard period may be applied.

The maximum number of lower uplink bandwidth parts that can be configured in the terminal may be determined through a capability report of the terminal or may not be related to the capability report.

As another example, a method of operating a lower uplink bandwidth part having a center frequency different from that of the upper uplink bandwidth part and having frequency resources overlapping with the upper uplink and downlink bandwidth parts may be considered. .

When the terminal receives one downlink bandwidth part and a plurality of uplink bandwidth parts from the base station, the lower uplink bandwidth part has a center frequency different from the upper uplink bandwidth part and the frequency resources are all overlapped. By operating the part, the delay time required to change from the downlink bandwidth part to the uplink bandwidth part can be reduced.

11 is a diagram illustrating an example of setting a bandwidth part according to an embodiment of the present disclosure.

According to an embodiment of the present disclosure, a terminal may be configured with one downlink bandwidth part and a plurality of uplink bandwidth parts through higher layer signaling from a base station. 11 is an example in which downlink bandwidth part #1 1105, uplink upper bandwidth part #1 1110, uplink upper bandwidth part #2 1125, and uplink lower bandwidth part #1-2 1120 are set. shows

Referring to FIG. 11, the terminal receives one downlink bandwidth part #1 1105 from the base station, two upper uplink bandwidth parts #1 1110 and #2 1125, and one lower uplink bandwidth part # 1-2 (1120) can be set. At this time, the lower uplink bandwidth part # 1-2 1120 may have the following characteristics:

- The lower uplink bandwidth part #1-2 (1120) may be set to have a center frequency different from that of the downlink bandwidth part #1 (1105) and the upper uplink bandwidth part #1 (1110). And, the bandwidth size of the lower uplink bandwidth part #1-2 (1120) may be formed within the downlink bandwidth part #1 (1105) and the upper uplink bandwidth part #1 (1110).

In the setting information of the lower uplink bandwidth part # 1-2 (1120), as part of the setting information of the upper uplink bandwidth part # 1 (1110), parameters related to transmission and reception (e.g., see Tables 2, 4, and 5) may be included in whole or in part.

While receiving a downlink signal through downlink bandwidth part #1 1105, the terminal may be instructed to change to a new uplink bandwidth part, for example, a lower uplink bandwidth part # 1-2 1120 through DCI. there is. The contents of the bandwidth part change indicator will be described in detail in the fourth embodiment.

As shown in 1130 of FIG. 11, while receiving a downlink signal in downlink bandwidth part # 1 1105, the terminal may be instructed to change to lower uplink bandwidth part # 1-2 1120 through DCI ( 1130). At this time, the remaining part of the previously set downlink bandwidth part # 1 may be deactivated (1115), and the downlink symbol -> uplink symbol guard period (Guard Period) (ie, from downlink symbol to uplink symbol After the guard time for change/switching) has elapsed, the lower uplink bandwidth #1-2 1120 can be activated.

When the UE changes from the downlink bandwidth part #1 1105 to the lower uplink bandwidth parts #1-2 1120, a guard period in symbol units (μs) may be required, which means that the UE It may be shorter than the required bandwidth part change delay time (BWP switching delay) in units of ms when changing from bandwidth part #1 1105 to higher uplink bandwidth part #2 1125.

As another example, a method of operating a lower uplink bandwidth part having a center frequency different from that of the upper uplink bandwidth part and having frequency resources partially overlapping with the upper uplink and downlink bandwidth parts may be considered. there is.

When a terminal receives one downlink bandwidth part and a plurality of uplink bandwidth parts from a base station, the lower uplink bandwidth part has a center frequency different from that of the upper uplink bandwidth part, and the frequency resources partially overlap. By operating the bandwidth part, a delay time required for changing from a downlink bandwidth part to an uplink bandwidth part can be reduced.

12 is a diagram illustrating an example of setting a bandwidth part according to an embodiment of the present disclosure.

According to an embodiment of the present disclosure, a terminal may be configured with one downlink bandwidth part and a plurality of uplink bandwidth parts through higher layer signaling from a base station. 12 is an example in which downlink bandwidth part #1 1205, upper uplink bandwidth part #1 1210, upper uplink bandwidth part #2 1225, and lower uplink bandwidth parts #1-3 1220 are set. shows

Referring to FIG. 12, a terminal receives one downlink bandwidth part #1 1205 from a base station, two upper uplink bandwidth parts #1 1210 and #2 1225, and one lower uplink bandwidth part #1 -3 (1220) can be set. At this time, the lower uplink bandwidth part # 1-3 1220 may have the following characteristics:

- The lower uplink bandwidth part #1-3 (1220) may be set to have a center frequency different from that of the downlink bandwidth part #1 (1205) and the upper uplink bandwidth part #1 (1215). And, the bandwidth size of the lower uplink bandwidth part #1-3 (1220) may partially overlap with the downlink bandwidth part #1 (1205) and the upper uplink bandwidth part #1 (1210).

In the setting information of the lower uplink bandwidth part #1-3 (1220), as part of the setting information of the upper uplink bandwidth part #1 (1210), parameters related to transmission and reception (e.g., see Tables 2, 4, and 5) may be included in whole or in part.

While receiving a downlink signal through downlink bandwidth part #1 1205, the terminal may be instructed to change to a new uplink bandwidth part, for example, a lower uplink bandwidth part #1-3 1220 through DCI. there is. The contents of the bandwidth part change indicator will be described in detail in the fourth embodiment.

As shown in 1230 of FIG. 12, while receiving a downlink signal in downlink bandwidth part #1 1205, the UE may be instructed to change to lower uplink bandwidth part #1-3 1220 through DCI ( 1230). At this time, the remaining part of the previously set downlink bandwidth part # 1 may be deactivated (1215), and downlink symbol -> uplink symbol guard period (ie, from downlink symbol to uplink symbol After the guard time for change/switching) has elapsed, the lower uplink bandwidth #1-3 1220 can be activated.

When the terminal changes from the downlink bandwidth part #1 1205 to the lower uplink bandwidth parts #1-3 1220, a guard period in symbol units (e.g., μs) may be required, which means that the terminal When changing from downlink bandwidth part #1 1205 to higher uplink bandwidth part #2 1225, it may be shorter than the required bandwidth part change delay time (BWP switching delay) in ms.

As another example, a method of operating a lower uplink bandwidth part having a center frequency different from that of the upper uplink bandwidth part and having frequency resources that do not overlap with the upper uplink and downlink bandwidth parts may be considered. .

When the terminal receives one downlink bandwidth part and a plurality of uplink bandwidth parts from the base station, the lower uplink bandwidth part has a center frequency different from the upper uplink bandwidth part and the frequency resources do not overlap. By operating the part, the delay time required to change from the downlink bandwidth part to the uplink bandwidth part can be reduced.

13 is a diagram illustrating an example of setting a bandwidth part according to an embodiment of the present disclosure.

According to an embodiment of the present disclosure, a terminal may be configured with one downlink bandwidth part and a plurality of uplink bandwidth parts through higher layer signaling from a base station. 13 is an example in which downlink bandwidth part #1 1305, upper uplink bandwidth part #1 1310, upper uplink bandwidth part #2 1325, and lower uplink bandwidth parts #1-4 1320 are set. shows

Referring to FIG. 13, a terminal receives one downlink bandwidth part #1 1305 from a base station, two upper uplink bandwidth parts #1 1310 and #2 1325, and one lower uplink bandwidth part #1 -4 (1320) can be set. At this time, the lower uplink bandwidth parts # 1-4 1320 may have the following characteristics:

- The lower uplink bandwidth part #1-4 (1320) may be set to have a center frequency different from that of the downlink bandwidth part #1 (1405) and the upper uplink bandwidth part #1 (1315). Also, the bandwidth size of the lower uplink bandwidth part #1-4 (1320) may be formed so as not to overlap with the downlink bandwidth part #1 (1305) and the upper uplink bandwidth part #1 (1310).

In the setting information of the lower uplink bandwidth part # 1-4 (1320), as part of the setting information of the upper uplink bandwidth part # 1 (1310), parameters related to transmission and reception (e.g., see Tables 2, 4, and 5) may be included in whole or in part.

While receiving a downlink signal through downlink bandwidth part #1 1305, the terminal may be instructed to change to a new uplink bandwidth part, for example, lower uplink bandwidth parts # 1-4 1320 through DCI. there is. The contents of the bandwidth part change indicator will be described in detail in the fourth embodiment.

As shown in 1330 of FIG. 13, while receiving a downlink signal in downlink bandwidth part # 1 1305, the terminal may be instructed to change to lower uplink bandwidth parts # 1-4 1320 through DCI ( 1330). At this time, the remaining part of the previously set downlink bandwidth part # 1 may be deactivated (1315), and the downlink symbol -> uplink symbol guard period (ie, from downlink symbol to uplink symbol After the guard time for changing/switching) has elapsed, the lower uplink bandwidths #1-4 1320 can be activated.

When the UE changes from the downlink bandwidth part #1 1305 to the lower uplink bandwidth parts #1-4 1320, a symbol unit (e.g., μs) guard period may be required, which means that the UE When changing from downlink bandwidth part #1 1305 to higher uplink bandwidth part #2 1325, it may be shorter than the required bandwidth part change delay time (BWP switching delay) in ms.

For convenience of description, the second embodiment has been described focusing on an example of changing from a downlink bandwidth part to an uplink bandwidth part when one downlink bandwidth part and a plurality of uplink bandwidth parts are set, but the scope of the present disclosure is not limited thereto. Accordingly, when one uplink bandwidth part and a plurality of downlink bandwidth parts are set, it can be applied to an example of changing from an uplink bandwidth part to a downlink bandwidth part, of course.

The third embodiment proposes a method of reducing a delay time required for a terminal to receive a plurality of downlink bandwidth parts from a base station and change from a downlink bandwidth part to an uplink bandwidth part.

The plurality of downlink bandwidth parts configured by the terminal from the base station may include at least one upper downlink bandwidth part and at least one lower downlink bandwidth part. One of the at least one upper downlink bandwidth part may have the same center frequency as the uplink bandwidth part. Also, the lower uplink bandwidth part may refer to a bandwidth part having a smaller size (or smaller or equal to) that of an upper downlink bandwidth part having the same center frequency as the uplink bandwidth part. For example, a method of operating a lower downlink bandwidth part having the same center frequency as the upper downlink bandwidth part and having frequency resources overlapping with the upper downlink bandwidth part may be considered.

When the terminal receives a plurality of downlink bandwidth parts and one uplink bandwidth part from the base station, the lower downlink bandwidth part has the same center frequency as the upper downlink bandwidth part and the frequency resources overlap with the lower downlink bandwidth part It is possible to reduce the delay time required to change from the downlink bandwidth part to the uplink bandwidth part by operating.

14 is a diagram illustrating an example of setting a bandwidth part according to an embodiment of the present disclosure.

According to an embodiment of the present disclosure, a terminal may be configured with a plurality of downlink bandwidth parts and one uplink bandwidth part through higher layer signaling from a base station. 14 shows an example in which downlink bandwidth part #1 1405, upper uplink bandwidth part #1 1415, and lower downlink bandwidth part #1-1 1410 are configured.

Referring to FIG. 14, a terminal receives one upper downlink bandwidth part #1 1405, a lower downlink bandwidth part #1-1 1410, and one upper uplink bandwidth part #1 1415 from a base station. can be set. At this time, the lower downlink bandwidth part # 1-1 1410 may have the following characteristics:

- The lower downlink bandwidth part #1-1 (1410) may be set to have the same center frequency as the upper downlink bandwidth part #1 (1405) and the uplink bandwidth part #1 (1415). Also, the bandwidth size of the lower downlink bandwidth part #1-1 (1410) may overlap with the upper downlink bandwidth part #1 (1405).

In the setting information of the lower downlink bandwidth part #1-1 (1410), as part of the setting information of the upper downlink bandwidth part #1 (1405), parameters related to transmission and reception (e.g., see Tables 2, 4, and 5) may be included in whole or in part.

While receiving a downlink signal through downlink bandwidth part #1 1405, the UE may be instructed to change to a new downlink bandwidth part, for example, lower downlink bandwidth part #1-1 1410 through DCI. there is. The contents of the bandwidth part change indicator will be described in detail in the fourth embodiment.

15 illustrates an example of setting a bandwidth part according to an embodiment of the present disclosure.

Referring to FIG. 15, while receiving a downlink signal in downlink bandwidth part #1 1505 as shown in 1520 of FIG. 15, the terminal changes to lower downlink bandwidth part #1-1 1510 through DCI. can be instructed (1520).

The terminal may receive a downlink signal from the lower downlink bandwidth part #1-1 (1510) activated through DCI, and when all time resources of the lower downlink bandwidth part #1-1 (1510) are exhausted, the downlink Link symbol -> uplink symbol guard period (ie, guard period for changing/switching from downlink symbol to uplink symbol) (1525), after which uplink bandwidth part # 1 (1530) is activated It can be.

The uplink bandwidth part #1 1530 has the same frequency resources as the preset higher uplink bandwidth part #1 1515 and has increased time resources, and can reduce delay time for uplink transmission of the terminal.

At this time, resources other than the time and frequency resources of the lower downlink bandwidth part #1-1 (1510) and the uplink bandwidth part #1 in the existing upper downlink bandwidth part #1 can be utilized by other users.

When the terminal changes from the lower downlink bandwidth part #1-1 (1510) to the uplink bandwidth part #1 (1530), a symbol unit (e.g., μs) guard period may be required, which means that the terminal It may be shorter than the bandwidth part change delay time (BWP switching delay) in ms units required when changing the bandwidth part itself.

The maximum number of lower downlink bandwidth parts that can be configured in the terminal may be determined through a capability report of the terminal or may not be related to the capability report.

As another example, a method of operating a lower downlink bandwidth part having a center frequency different from that of the upper downlink bandwidth part and having frequency resources completely or partially overlapping with the upper downlink bandwidth part may be considered.

When a terminal receives a plurality of downlink bandwidth parts and one uplink bandwidth part from a base station, the lower downlink bandwidth part has a center frequency different from that of the upper downlink bandwidth part and the frequency resources overlap in whole or in part. By operating the link bandwidth part, the delay time required to change from the downlink bandwidth part to the uplink bandwidth part can be reduced.

16 is a diagram illustrating an example of setting a bandwidth part according to an embodiment of the present disclosure.

According to an embodiment of the present disclosure, a terminal may be configured with a plurality of downlink bandwidth parts and one uplink bandwidth part through higher layer signaling from a base station. 16 shows an example in which the upper downlink bandwidth part #1 1605, the lower downlink bandwidth parts #1-2 1615, and the upper uplink bandwidth part #1 1610 are configured.

Referring to FIG. 16, a terminal receives one upper downlink bandwidth part #1 1605, lower downlink bandwidth parts #1-2 1615, and one upper uplink bandwidth part #1 1610 from a base station. can be set. At this time, the lower downlink bandwidth part # 1-2 1615 may have the following characteristics:

- The lower downlink bandwidth part #1-2 (1615) may be set to have a center frequency different from that of the upper downlink bandwidth part #1 (1605) and the uplink bandwidth part #1 (1610). In addition, the bandwidth size of the lower downlink bandwidth part #1-2 (1615) may overlap with the upper downlink bandwidth part #1 (1605) in whole or in part.

In the setting information of the lower downlink bandwidth part #1-2 (1615), as part of the setting information of the upper downlink bandwidth part #1 (1605), parameters related to transmission and reception (e.g., see Tables 2, 4, and 5) may be included in whole or in part.

While receiving a downlink signal through downlink bandwidth part #1 1605, the terminal may be instructed to change to a new downlink bandwidth part, for example, lower downlink bandwidth part #1-2 1615 through DCI. there is. The contents of the bandwidth part change indicator will be described in detail in the fourth embodiment.

As shown in 1620 of FIG. 16, while receiving a downlink signal in the upper downlink bandwidth part #1 1605, the UE may be instructed to change to the lower downlink bandwidth part #1-2 1615 through DCI. (1620).

The UE can receive a downlink signal in the lower downlink bandwidth part #1-2 activated through DCI, and when the time resources of the lower downlink bandwidth part #1-2 are exhausted, downlink symbol -> uplink After the symbol guard period 1625 (that is, the guard period for changing/switching from a downlink symbol to an uplink symbol) passes, the uplink bandwidth part # 1 1630 may be activated.

The uplink bandwidth part #1 1630 has the same frequency resources as the preset higher uplink bandwidth part #1 1610 and has increased time resources, and can reduce the delay time for uplink transmission of the terminal.

At this time, resources other than the time and frequency resources of the lower downlink bandwidth parts #1-2 and the uplink bandwidth part #1 in the existing upper downlink bandwidth part #1 can be utilized by other users.

When the UE changes from the lower downlink bandwidth part #1-2 1615 to the uplink bandwidth part #1 1630, a guard period in symbol units (e.g., μs) may be required, which means that the UE It may be shorter than the bandwidth part change delay time (BWP switching delay) in ms units required when changing the bandwidth part itself.

As another example, a method of operating a lower downlink bandwidth part having a center frequency different from that of the upper downlink bandwidth part and having frequency resources that do not overlap with the upper downlink bandwidth part may be considered.

When the terminal receives a plurality of downlink bandwidth parts and one uplink bandwidth part from the base station, the lower downlink bandwidth part has a center frequency different from the upper downlink bandwidth part and the frequency resources do not overlap. By operating the part, the delay time required to change from the downlink bandwidth part to the uplink bandwidth part can be reduced.

17 is a diagram illustrating an example of setting a bandwidth part according to an embodiment of the present disclosure.

According to an embodiment of the present disclosure, a terminal may be configured with a plurality of downlink bandwidth parts and one uplink bandwidth part through higher layer signaling from a base station. 17 shows an example in which the upper downlink bandwidth part #1 1705, the lower downlink bandwidth parts #1-3 1715, and the upper uplink bandwidth part #1 1710 are configured.

Referring to FIG. 17, a terminal receives one upper downlink bandwidth part #1 1705, lower downlink bandwidth parts #1-3 1715, and one upper uplink bandwidth part #1 1710 from a base station. can be set. At this time, the lower downlink bandwidth part # 1-3 1715 may have the following characteristics:

- The lower downlink bandwidth part #1-3 (1715) can be set to have a center frequency different from that of the upper downlink bandwidth part #1 (1705) and the uplink bandwidth part #1 (1710). And, the lower downlink bandwidth part #1 (1715). The bandwidth size of the link bandwidth part #1-3 (1715) may not overlap with the upper downlink bandwidth part #1 (1705).

In the setting information of the lower downlink bandwidth part #1-3 (1715), as part of the setting information of the upper downlink bandwidth part #1 (1705), parameters related to transmission and reception (e.g., see Tables 2, 4, and 5) may be included in whole or in part.

While receiving a downlink signal through downlink bandwidth part #1 1705, the UE may be instructed to change to a new downlink bandwidth part, for example, lower downlink bandwidth part #1-3 1715 through DCI. there is. The contents of the bandwidth part change indicator will be described in detail in the fourth embodiment.

As shown in 1720 of FIG. 17, while receiving a downlink signal in the upper downlink bandwidth part #1 1705, the UE may be instructed to change to the lower downlink bandwidth part #1-3 1715 through DCI. (1720).

The UE may receive a downlink signal from the lower downlink bandwidth part #1-3 1715 activated through DCI, and when all time resources of the lower downlink bandwidth part #1-3 are exhausted, the downlink symbol- >Uplink bandwidth part # 1 1730 can be activated after the uplink symbol guard period 1725 (that is, the guard time for changing/switching from a downlink symbol to an uplink symbol) has elapsed .

The uplink bandwidth part #1 1730 has the same frequency resources as the preset higher uplink bandwidth part #1 1710 and has increased time resources, and can reduce the delay time for uplink transmission of the terminal.

At this time, resources other than the time and frequency resources of the uplink bandwidth part #1 in the existing upper downlink bandwidth part #1 can be utilized by other users.

When the UE changes from the lower downlink bandwidth part #1-3 1715 to the uplink bandwidth part #1 1730, a symbol unit (e.g., μs) guard period may be required, which means that the UE It may be shorter than the bandwidth part change delay time (BWP switching delay) in ms units required when changing the bandwidth part itself.

For convenience of description, the third embodiment has been described focusing on an example of changing from a downlink bandwidth part to an uplink bandwidth part when a plurality of downlink bandwidth parts and one uplink bandwidth part are set, but the scope of the present disclosure is not limited thereto. Accordingly, when a plurality of uplink bandwidth parts and one downlink bandwidth part are set, it can be applied to an example of changing from an uplink bandwidth part to a downlink bandwidth part, of course.

The fourth embodiment describes a method in which the base station instructs the terminal to activate the lower downlink bandwidth part or the uplink bandwidth part in the second and third embodiments. Specifically, a method of indicating a lower bandwidth part by reinterpreting the BWP indicator field in the existing DCI will be described.

For example, N upper bandwidth parts may be set for the terminal, and each upper bandwidth part may be composed of M lower bandwidth parts. The bandwidth part change indicator in the DCI may indicate a combination of an upper bandwidth part index and a lower bandwidth part index. For example, when N upper bandwidth parts and M lower bandwidth parts are set,

A DCI field corresponding to bits may indicate a specific upper or lower bandwidth field to be activated.

As another example, if a total of L bandwidth parts are set,

A specific bandwidth part to be activated may be indicated by a BWP indicator field in DCI corresponding to bits. In this case, L may mean the sum of the number of upper bandwidth parts and the number of lower bandwidth parts.

The embodiments and/or methods proposed in this disclosure may be performed in combination with each other. In addition, an operation of one embodiment may be performed as part of another embodiment or replaced with some methods of another embodiment.

18 is a block diagram illustrating a procedure for determining a guard time generated when a terminal changes from downlink to uplink according to characteristics of a bandwidth part set by a base station according to an embodiment of the present disclosure. Operations of FIG. 18 may be performed based on the second embodiment of the present disclosure.

In step 1801, the terminal may receive setting information on a higher bandwidth part. In step 1802, the terminal may receive setting information for a lower bandwidth part.

Steps

1801 and 1802 may be combined and performed as one step.

In step 1803, the terminal can determine whether to change from the upper downlink bandwidth part to the lower uplink bandwidth part. Changes to the bandwidth part can be triggered in various ways. For example, the terminal may receive an activation message for a specific bandwidth part from the base station through higher layer signaling, and if the indicated bandwidth part corresponds to a bandwidth part different from the currently activated bandwidth part, the bandwidth part can be changed. can As another example, the terminal may receive an activation indicator for a specific bandwidth part from the base station through L1 signaling (e.g., DCI), and if the indicated bandwidth part corresponds to a bandwidth part different from the currently activated bandwidth part, Bandwidth part can be changed. For another example, when a timer for the bandwidth part expires, the terminal may change the bandwidth part to a default bandwidth part. For another example, the terminal may receive a preset pattern for a bandwidth part to be activated at a specific time point from the base station, and periodically change the bandwidth part according to time based on the setting information.

When it is determined in step 1803 that BWP change is to be performed, in step 1805, the terminal may determine whether or not the center frequency of the instructed lower uplink bandwidth part coincides with that of the upper uplink bandwidth part.

If it is determined that the center frequencies match in step 1805, the terminal can determine whether or not the lower uplink bandwidth part resource instructed in step 1806 completely overlaps within the upper uplink bandwidth part resource.

If, in step 1806, the lower uplink bandwidth part resource completely overlaps within the upper uplink bandwidth part resource, a value X may be applied as a downlink->uplink protection time to the UE (1807), which is defined in Table 3 It may be shorter than the bandwidth part change delay time. As an example, the value of X may be in symbol units (e.g., μs).

If the bandwidth part resources do not overlap in step 1806, the value Y may be applied as the downlink->uplink protection time (1808), which may be shorter than the bandwidth part change delay time defined in Table 3, and X of 1807 It can be greater than or equal to the value. As an example, the Y value may be in symbol units (e.g., μs).

If the center frequencies do not match in step 1805, the terminal can determine whether the lower uplink bandwidth part resource indicated in step 1809 completely overlaps within the upper uplink bandwidth part resource.

At this time, if the resources completely overlap, the Z value can be applied as the downlink->uplink protection time in 1810, which is shorter than the bandwidth part change delay time defined in Table 3 and greater than or equal to the Y value of 1808. . As an example, the Z value may be in symbol units (e.g., μs).

If the resources do not completely overlap in step 1809, the terminal may perform a determination as to whether the lower uplink bandwidth part resource indicated in step 1811 partially coincides with the upper uplink bandwidth part resource.

If it is determined that the lower uplink bandwidth part resource indicated in step 1811 partially matches the upper uplink bandwidth part resource, the terminal may apply M value as the downlink->uplink guard time in step 1813, This may be shorter than the bandwidth part change delay time defined in Table 3 and greater than or equal to the Z value of 1810. As an example, the M value may be a symbol unit (e.g., μs).

If they do not partially match in step 1811, the UE may apply N as the downlink->uplink protection time in step 1812, which may be shorter than the bandwidth part change delay time defined in Table 3, and may be shorter than the M value of 1813. can be greater than or equal to As an example, the N value may be a symbol unit (e.g., μs).

The terminal can expect that no transmission/reception is performed during the guard time for changing/switching from downlink to uplink.

19 is a block diagram illustrating a procedure for determining a guard time generated when a terminal changes from downlink to uplink according to characteristics of a bandwidth part set by a base station according to an embodiment of the present disclosure. Operations of FIG. 19 may be performed based on the third embodiment of the present disclosure.

In step 1901, the terminal may receive setting information on a higher bandwidth part. In step 1902, the terminal may receive setting information for a lower bandwidth part.

Steps

1901 and 1902 may be combined and performed as one step.

In step 1903, the terminal can determine whether to change from the upper downlink bandwidth part to the lower downlink bandwidth part. Changes to the bandwidth part can be triggered in various ways. For example, the terminal may receive an activation message for a specific bandwidth part from the base station through higher layer signaling, and if the indicated bandwidth part corresponds to a bandwidth part different from the currently activated bandwidth part, the bandwidth part can be changed. can As another example, the terminal may receive an activation indicator for a specific bandwidth part from the base station through L1 signaling (e.g., DCI), and if the indicated bandwidth part corresponds to a bandwidth part different from the currently activated bandwidth part, Bandwidth part can be changed. For another example, when a timer for the bandwidth part expires, the terminal may change the bandwidth part to a default bandwidth part. For another example, the terminal may receive a preset pattern for a bandwidth part to be activated at a specific time point from the base station, and periodically change the bandwidth part according to time based on the setting information.

When it is determined in step 1903 that a change is to be performed, the terminal may determine whether the center frequency of the lower downlink bandwidth part instructed in step 1905 coincides with the upper uplink bandwidth part.

If it is determined that the center frequencies coincide in step 1905, the terminal may determine whether or not the lower downlink bandwidth part resource instructed in step 1906 completely overlaps within the upper downlink bandwidth part resource.

If, in step 1906, the lower downlink bandwidth part resource completely overlaps within the upper downlink bandwidth part resource, when the UE changes from the lower downlink bandwidth part to the upper uplink bandwidth part thereafter, the X value may be applied as a guard time ( 1907), which may be shorter than the bandwidth part change delay time defined in Table 3. As an example, the value of X may be in symbol units (e.g., μs).

If the bandwidth part resources do not overlap in step 1906, when the terminal changes from the lower downlink bandwidth part to the upper uplink bandwidth part, the Y value may be applied as the guard time (1908), which is the bandwidth part defined in Table 3 It may be shorter than the change delay time, and may be greater than or equal to the X value of 1907. As an example, the Y value may be in symbol units (e.g., μs).

If the center frequencies do not match in step 1905, the terminal can determine whether the lower downlink bandwidth part resource indicated in step 1909 completely overlaps within the upper downlink bandwidth part resource.

At this time, if the resources completely overlap, the Z value can be applied as a guard time when the terminal changes from the lower downlink bandwidth part to the upper uplink bandwidth part in 1910, which is more than the bandwidth part change delay time defined in Table 3. It is shorter and can be greater than or equal to the Y value of 1908. As an example, the Z value may be in symbol units (e.g., μs).

If the resources do not completely overlap in step 1909, the terminal may perform a determination as to whether the lower downlink bandwidth part resource indicated in step 1911 partially matches the upper downlink bandwidth part resource.

If it is determined that the lower downlink bandwidth part resource indicated in step 1911 partially matches the upper downlink bandwidth part resource, the terminal protects the guard time when changing from the lower downlink bandwidth part to the upper uplink bandwidth part in step 1913 As a result, an M value may be applied, which may be shorter than the bandwidth part change delay time defined in Table 3 and greater than or equal to the Z value of 1910. As an example, the M value may be a symbol unit (e.g., μs).

If they do not partially match in step 1911, the terminal may apply a guard time N value when the terminal changes from a lower downlink bandwidth part to a higher uplink bandwidth part in 1912, which is longer than the bandwidth part change delay time defined in Table 3. It may be shorter, and may be greater than or equal to the M value of 1913. As an example, the M value may be a symbol unit (e.g., μs).

The terminal can expect that no transmission/reception is performed during the guard time for changing/switching from the lower downlink bandwidth part to the upper uplink bandwidth part.

20 is an example of an operation flowchart of a terminal according to an embodiment of the present disclosure. The terminal and/or the base station may perform the above-described embodiments and/or methods proposed in the present disclosure based on FIG. 20 .

20 is only an example to help understanding of the present disclosure, and does not limit the scope of the present disclosure. The operation sequences of FIG. 20 may be interchanged, or two or more steps may be merged and performed as one step. Also, some steps may be omitted in some cases.

The terminal may check a first BWP associated with the first communication direction and a plurality of BWPs associated with the second communication direction (S2010). To configure the BWP, the base station may transmit configuration information about the BWP to the terminal. For example, when the first communication direction is downlink, the second communication direction may be uplink. Alternatively, when the first communication direction is uplink, the second communication direction may be downlink.

For example, the plurality of BWPs associated with the second communication direction may include a second BWP and a third BWP. In this case, the center frequencies of the first BWP and the third BWP are the same, and the third BWP may have a bandwidth size larger than that of the second BWP. Also, the plurality of BWPs associated with the second communication direction may include a fourth BWP that does not overlap with the third BWP in a frequency domain.

For example, the plurality of BWPs associated with the second communication direction may consist of one or more upper BWPs (e.g., a third BWP) and one or more lower BWPs (e.g., a second BWP). Also, each higher BWP may include one or more lower BWPs.

The terminal may receive information indicating a change from the first BWP to the second BWP (S2020). The base station may transmit information indicating a change from the first BWP to the second BWP to the terminal.

For example, information indicating a change from the first BWP to the second BWP may be included in DCI. For example, the number of bits of the information field indicating BWP change in the DCI may be determined based on the number of upper BWPs and the number of lower BWPs. As another example, the number of bits of the information field indicating BWP change in the DCI may be determined based on the number of BWPs configured for the terminal.

The terminal may change from the first BWP to the second BWP based on the information (S2030). Specifically, the terminal may deactivate the first BWP from the time of receiving the information, and activate the second BWP after a protection time required for changing from the first BWP to the second BWP passes.

The guard time required for changing from the first BWP to the second BWP depends on whether the center frequencies of the second BWP and the third BWP are the same and whether the second BWP and the third BWP overlap in the frequency domain. can be determined based on

For example, when the center frequencies of the second BWP and the third BWP are the same, a first guard time may be required to change from the first BWP to the second BWP. When the center frequencies of the second BWP and the third BWP are different, a second guard time may be required to change from the first BWP to the second BWP. In this case, the second protection time may be longer than or equal to the first protection time. For example, the guard time may be a symbol unit (e.g., μs).

For example, when the center frequencies of the second BWP and the third BWP are different and the second BWP completely overlaps the third BWP in the frequency domain, to change from the first BWP to the second BWP A third guard time may be required. When the center frequencies of the second BWP and the third BWP are different and the second BWP partially overlaps the third BWP in the frequency domain, fourth protection for change from the first BWP to the second BWP Time may be required. In this case, the third protection time may be shorter than or equal to the fourth protection time. For example, the guard time may be a symbol unit (e.g., μs).

For example, the guard time required for changing from the first BWP to the second BWP may be shorter than the guard time required for changing from the first BWP to the fourth BWP. For example, the guard time required for changing from the first BWP to the second BWP may be a symbol unit (e.g., μs), and the guard time required for changing from the first BWP to the fourth BWP may be a slot unit (e.g., ms).

The terminal may transmit capability information related to BWP change to the base station. That is, the base station may receive capability information related to BWP change from the terminal. For example, the capability information related to the BWP change may include a delay time type required for the BWP change and information on the maximum number of BWPs changeable by the terminal.

The above-described embodiments and/or methods proposed in the present disclosure may be performed by the terminal of FIG. 21 and the base station of FIG. 22.

Referring to FIG. 21 , a terminal may include a terminal receiving unit 2100 and a transceiver that refers to a terminal transmitting unit 2110, a memory (not shown), and a terminal processing unit 2105 (or a terminal control unit or processor). According to the communication method of the terminal described above, the transmission/

reception units

2100 and 2110 of the terminal, the memory and the terminal processing unit 2105 may operate. However, the components of the terminal are not limited to the above-described examples. For example, a terminal may include more or fewer components than the aforementioned components. In addition, the transceiver, memory, and processor may be implemented in a single chip form.

The transmitting/receiving unit may transmit/receive signals with the base station. Here, the signal may include control information and data. To this end, the transceiver unit may include an RF transmitter for up-converting and amplifying the frequency of a transmitted signal, and an RF receiver for low-noise amplifying a received signal and down-converting the frequency. However, this is only one embodiment of the transceiver, and components of the transceiver are not limited to the RF transmitter and the RF receiver.

Also, the transceiver may receive a signal through a wireless channel, output the signal to the processor, and transmit the signal output from the processor through the wireless channel.

The memory may store programs and data required for operation of the terminal. In addition, the memory may store control information or data included in signals transmitted and received by the terminal. The memory may include a storage medium such as a ROM, a RAM, a hard disk, a CD-ROM, and a DVD, or a combination of storage media. Also, there may be a plurality of memories.

In addition, the processor may control a series of processes so that the terminal can operate according to the above-described embodiment. For example, the processor (control unit) may be configured to identify a first bandwidth part (BWP) associated with the first communication direction and a plurality of BWPs associated with the second communication direction. At this time, the plurality of BWPs associated with the second communication direction include a second BWP and a third BWP having a bandwidth size greater than that of the second BWP, and the center frequencies of the first BWP and the third BWP are the same. can do. In addition, the processor (control unit) may be set to receive information indicating a change from the first BWP to the second BWP, and to change the first BWP to the second BWP based on the information. The guard time required for changing from the first BWP to the second BWP depends on whether the center frequencies of the second BWP and the third BWP are the same and whether the second BWP and the third BWP overlap in the frequency domain. can be determined based on There may be a plurality of processors, and the processors may perform component control operations of the terminal by executing a program stored in a memory.

Referring to FIG. 22 , a base station may include a base station receiving unit 2200 and a transmitting/receiving unit that refers to a base station transmitting unit 2210, a memory (not shown), and a base station processing unit 2205 (or a base station control unit or processor). According to the communication method of the base station described above, the transmission/

reception units

2200 and 2210 of the base station, the memory and the base station processing unit 2205 can operate. However, components of the base station are not limited to the above-described examples. For example, a base station may include more or fewer components than those described above. In addition, the transceiver, memory, and processor may be implemented in a single chip form.

The transmission/reception unit may transmit/receive signals with the terminal. Here, the signal may include control information and data. To this end, the transceiver unit may include an RF transmitter for up-converting and amplifying the frequency of a transmitted signal, and an RF receiver for low-noise amplifying a received signal and down-converting the frequency. However, this is only one embodiment of the transceiver, and components of the transceiver are not limited to the RF transmitter and the RF receiver.

The memory may store programs and data necessary for the operation of the base station. In addition, the memory may store control information or data included in signals transmitted and received by the base station. The memory may include a storage medium such as a ROM, a RAM, a hard disk, a CD-ROM, and a DVD, or a combination of storage media. Also, there may be a plurality of memories.

The processor may control a series of processes so that the base station operates according to the above-described embodiment of the present disclosure. For example, the processor (control unit) transmits configuration information for configuring a first bandwidth part (BWP) associated with the first communication direction and a plurality of BWPs associated with the second communication direction to the terminal, and to the terminal, the first BWP It can be set to transmit information indicating a change from to the second BWP. At this time, the plurality of BWPs associated with the second communication direction include a second BWP and a third BWP having a bandwidth size greater than that of the second BWP, and the center frequencies of the first BWP and the third BWP are the same. can do. Also, based on the information, the first BWP may be changed to the second BWP. The guard time required for changing from the first BWP to the second BWP depends on whether the center frequencies of the second BWP and the third BWP are the same and whether the second BWP and the third BWP overlap in the frequency domain. can be determined based on There may be a plurality of processors, and the processors may perform a component control operation of the base station by executing a program stored in a memory.

Methods according to the embodiments described in the claims or specification of the present disclosure may be implemented in the form of hardware, software, or a combination of hardware and software.

When implemented in software, a computer readable storage medium storing one or more programs (software modules) may be provided. One or more programs stored in a computer-readable storage medium are configured for execution by one or more processors in an electronic device. The one or more programs include instructions that cause the electronic device to execute methods according to embodiments described in the claims or specification of the present disclosure.

Such programs (software modules, software) may include random access memory, non-volatile memory including flash memory, read only memory (ROM), and electrically erasable programmable ROM. (EEPROM: Electrically Erasable Programmable Read Only Memory), magnetic disc storage device, Compact Disc-ROM (CD-ROM), Digital Versatile Discs (DVDs), or other forms of It can be stored on optical storage devices, magnetic cassettes. Alternatively, it may be stored in a memory composed of a combination of some or all of these. In addition, each configuration memory may be included in multiple numbers.

In addition, the program accesses through a communication network such as the Internet, an Intranet, a Local Area Network (LAN), a Wide LAN (WLAN), or a Storage Area Network (SAN), or a communication network composed of a combination thereof. It can be stored on an attachable storage device that can be accessed. Such a storage device may be connected to a device performing an embodiment of the present disclosure through an external port. In addition, a separate storage device on a communication network may be connected to a device performing an embodiment of the present disclosure.

In the specific embodiments of the present disclosure described above, components included in the disclosure are expressed in singular or plural numbers according to the specific embodiments presented. However, the singular or plural expressions are selected appropriately for the presented situation for convenience of explanation, and the present disclosure is not limited to singular or plural components, and even components expressed in plural are composed of the singular number or singular. Even the expressed components may be composed of a plurality.

On the other hand, the embodiments of the present disclosure disclosed in the present specification and drawings are only presented as specific examples to easily explain the technical content of the present disclosure and help understanding of the present disclosure, and are not intended to limit the scope of the present disclosure. That is, it is obvious to those skilled in the art that other modifications based on the technical idea of the present disclosure are possible. In addition, each of the above embodiments can be operated in combination with each other as needed. For example, a base station and a terminal may be operated by combining parts of one embodiment of the present disclosure and another embodiment. For example, a base station and a terminal may be operated by combining parts of the first embodiment and the second embodiment of the present disclosure. In addition, although the above embodiments have been presented based on the FDD LTE system, other modifications based on the technical idea of the above embodiment may be implemented in other systems such as a TDD LTE system, 5G or NR system.

Meanwhile, the order of description in the drawings for explaining the method of the present disclosure does not necessarily correspond to the order of execution, and the order of precedence may be changed or executed in parallel.

Alternatively, drawings describing the method of the present disclosure may omit some components and include only some components within a range that does not impair the essence of the present disclosure.

In addition, the method of the present disclosure may be executed by combining some or all of the contents included in each embodiment within the scope of not detracting from the essence of the disclosure.

Various embodiments of the present disclosure have been described above. The foregoing description of the present disclosure is for illustrative purposes, and the embodiments of the present disclosure are not limited to the disclosed embodiments. Those of ordinary skill in the art to which the present disclosure belongs will be able to understand that it can be easily modified into other specific forms without changing the technical spirit or essential features of the present disclosure. The scope of the present disclosure is indicated by the following claims rather than the detailed description above, and all changes or modifications derived from the meaning and scope of the claims and equivalent concepts should be interpreted as being included in the scope of the present disclosure. do.

Claims

In a method performed by a terminal in a wireless communication system,

Identifying a first bandwidth part (BWP) associated with a first communication direction and a plurality of BWPs associated with a second communication direction, wherein the plurality of BWPs associated with the second communication direction include a second BWP and a bandwidth of the second BWP a third BWP having a bandwidth size greater than the bandwidth size, and center frequencies of the first BWP and the third BWP are the same;

Receiving information indicating a change from the first BWP to the second BWP; and

Changing from the first BWP to the second BWP based on the information,

The guard time required for changing from the first BWP to the second BWP depends on whether the center frequencies of the second BWP and the third BWP are the same and whether the second BWP and the third BWP overlap in the frequency domain. determined based on the method.
According to claim 1,

When the center frequencies of the second BWP and the third BWP are the same, a first guard time is required to change from the first BWP to the second BWP;

When the center frequencies of the second BWP and the third BWP are different, a second guard time is required to change from the first BWP to the second BWP, and

wherein the second guard time is greater than or equal to the first guard time.
In claim 1,

The center frequencies of the second BWP and the third BWP are different,

When the second BWP completely overlaps the third BWP in the frequency domain, a third guard time is required to change from the first BWP to the second BWP,

When the second BWP partially overlaps the third BWP in the frequency domain, a fourth guard time is required to change from the first BWP to the second BWP, and

wherein the third guard time is less than or equal to the fourth guard time.
According to claim 1,

The plurality of BWPs associated with the second communication direction include a fourth BWP that does not overlap with the third BWP in a frequency domain;

The guard time required for changing from the first BWP to the second BWP is shorter than the guard time required for changing from the first BWP to the fourth BWP.
According to claim 1,

Further comprising the step of transmitting capability information related to BWP change,

The method characterized in that the capability information related to the BWP change includes a delay time type required for the BWP change and information on the maximum number of BWPs changeable by the terminal.
According to claim 1,

The plurality of BWPs are composed of one or more upper BWPs and one or more lower BWPs, each upper BWP including one or more lower BWPs,

Information indicating a change from the first BWP to the second BWP is included in downlink control information (DCI), and

Characterized in that the number of bits of the field indicating the information in the DCI is determined based on the number of the upper BWPs and the number of the lower BWPs.
According to claim 1,

Further comprising the step of receiving setting information for BWP,

The step of changing from the first BWP to the second BWP,

deactivating the first BWP from the time of receiving the information; and

and activating the second BWP after the guard time has elapsed.
In a method performed by a base station in a wireless communication system,

Transmitting configuration information for configuring a first bandwidth part (BWP) associated with a first communication direction and a plurality of BWPs associated with a second communication direction to a terminal, the plurality of BWPs associated with the second communication direction being second BWPs and a third BWP having a bandwidth size greater than that of the second BWP, wherein center frequencies of the first BWP and the third BWP are the same; and

Transmitting information indicating a change from the first BWP to the second BWP to the terminal,

Based on the information, the first BWP is changed to the second BWP, and

The guard time required for changing from the first BWP to the second BWP depends on whether the center frequencies of the second BWP and the third BWP are the same and whether the second BWP and the third BWP overlap in the frequency domain. determined based on the method.
According to claim 8,

When the center frequencies of the second BWP and the third BWP are the same, a first guard time is required to change from the first BWP to the second BWP;

When the center frequencies of the second BWP and the third BWP are different, a second guard time is required to change from the first BWP to the second BWP, and

wherein the second guard time is greater than or equal to the first guard time.
In paragraph 8,

The center frequencies of the second BWP and the third BWP are different,

When the second BWP completely overlaps the third BWP in the frequency domain, a third guard time is required to change from the first BWP to the second BWP,

When the second BWP partially overlaps the third BWP in the frequency domain, a fourth guard time is required to change from the first BWP to the second BWP, and

wherein the third guard time is less than or equal to the fourth guard time.
According to claim 8,

Further comprising receiving, from the terminal, capability information related to BWP change,

The method characterized in that the capability information related to the BWP change includes a delay time type required for the BWP change and information on the maximum number of BWPs changeable by the terminal.
According to claim 8,

The plurality of BWPs are composed of one or more upper BWPs and one or more lower BWPs, each upper BWP including one or more lower BWPs,

Information indicating a change from the first BWP to the second BWP is included in downlink control information (DCI), and

Characterized in that the number of bits of the field indicating the information in the DCI is determined based on the number of the upper BWPs and the number of the lower BWPs.
In the terminal of the wireless communication system,

Transmitting and receiving unit for transmitting and receiving signals; and

Including a control unit connected to the transceiver,

The control unit,

Check a first bandwidth part (BWP) associated with the first communication direction and a plurality of BWPs associated with the second communication direction, wherein the plurality of BWPs associated with the second communication direction are a second BWP and a bandwidth size of the second BWP. It includes a third BWP having a larger bandwidth size, and the center frequencies of the first BWP and the third BWP are the same,

Receiving information indicating a change from the first BWP to the second BWP, and

It is set to change from the first BWP to the second BWP based on the information, and

The guard time required for changing from the first BWP to the second BWP depends on whether the center frequencies of the second BWP and the third BWP are the same and whether the second BWP and the third BWP overlap in the frequency domain. The terminal, which is determined based on.
According to claim 13,

When the center frequencies of the second BWP and the third BWP are the same, a first guard time is required to change from the first BWP to the second BWP;

When the center frequencies of the second BWP and the third BWP are different and the second BWP completely overlaps the third BWP in the frequency domain, a second guard time for changing from the first BWP to the second BWP is required,

When the center frequencies of the second BWP and the third BWP are different and the second BWP partially overlaps the third BWP in the frequency domain, third protection for a change from the first BWP to the second BWP time required, and

A terminal characterized in that the first guard time < the second guard time < the third guard time.
In a base station of a wireless communication system,

Transmitting and receiving unit for transmitting and receiving signals; and

Including a control unit connected to the transceiver,

The control unit,

Transmits configuration information for setting a first bandwidth part (BWP) associated with a first communication direction and a plurality of BWPs associated with a second communication direction to a terminal, wherein the plurality of BWPs associated with the second communication direction are configured to include a second BWP and A third BWP having a bandwidth size greater than that of the second BWP, the center frequencies of the first BWP and the third BWP being the same, and

It is set to transmit information indicating a change from the first BWP to the second BWP to the terminal,

Based on the information, the first BWP is changed to the second BWP, and

The guard time required for changing from the first BWP to the second BWP depends on whether the center frequencies of the second BWP and the third BWP are the same and whether the second BWP and the third BWP overlap in the frequency domain. Base station, determined based on.