KR20190100042A - Method for bandwidth management part in communication system and apparatus for the same - Google Patents

Abstract

Disclosed are a method and apparatus for changing a bandwidth management part (BWP) in a communication system. According to the present invention, an operation method of a terminal comprises the steps of: receiving BWP change information from a base station at a BWP i; changing an operation BWP of the terminal from the BWP i to a BWP j even when the BWP change information is not completed, even when a procedure of transmitting and receiving first data in the BWP i is not completed; and performing a procedure of transmitting and receiving second data in the BWP j. Accordingly, the performance of the communication system can be improved.

Description

METHOD FOR BANDWIDTH MANAGEMENT PART IN COMMUNICATION SYSTEM AND APPARATUS FOR THE SAME

The present invention relates to a bandwidth part (BWP) operation technology in a communication system, and more particularly, to a BWP change and switch technology for preventing transmission delay of data and ensuring transmission reliability of data.

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

4G communication systems as well as frequency bands (for example, frequency bands below 6 GHz) of 4G communication systems for processing of rapidly increasing wireless data after commercialization of 4G communication systems (eg, communication systems supporting LTE). 5G communication systems (e.g., communication systems supporting NR) that use a higher frequency band (e.g., a frequency band of 6 GHz or more) than are considered. The 5G communication system may support Enhanced Mobile BroadBand (eMBB), Ultra-Reliable and Low Latency Communication (URLLC), and Massive Machine Type Communication (mMTC).

As the number of users increases, there is a need for a method for improving the quality of communication services. In order to improve the quality of the communication service, a method for reducing transmission delay, a method for improving reliability by improving the (re) transmission performance of data, and flexibility and scalability in consideration of the characteristics of the terminal and the characteristics of the communication service There is a need for a method for providing a communication service, a method for providing a communication service reflecting frequency operation regulation and frequency characteristics, and a method for transmitting high speed data (or high capacity data) according to a user's request.

In particular, when the data transmission procedure is not completed in the current BWP at the time of changing or switching the bandwidth part (BWP), BWP operation methods for preventing transmission delay of data and ensuring transmission reliability of data will be required.

An object of the present invention for solving the above problems is to provide a method and apparatus for operating bandwidth part (BWP) in a communication system.

A method of operating a terminal according to a first embodiment of the present invention for achieving the above object comprises the steps of: receiving BWP change information from a base station in BWP i; Changing the operation BWP of the terminal from BWP i to BWP j even when the BWP change time indicated by the BWP change information is not completed, even when the procedure of transmitting and receiving the first data in the BWP i is not completed; And performing a transmission / reception procedure of the second data in the BWP j, wherein the BWP i and the BWP j are different BWPs, and i and j are different integers.

Here, at the BWP change time point, the procedure of transmitting / receiving the first data may be terminated and the soft bit for the first data stored in the buffer of the terminal or the base station may be deleted.

Here, in the operation method of the terminal, when the transmission and reception procedure of the first data is suspended at the time of the BWP change, when the transmission and reception procedure of the second data is completed in the BWP j, the operation BWP in the BWP j to the BWP changing to i; And resuming a transmission / reception procedure of the reserved first date at the BWP i.

Here, the BWP change information may be received through at least one of an RRC message, a MAC CE, and a downlink control channel.

Here, the BWP change information may be received through a downlink control channel together with resource allocation information for the first data.

Here, the BWP change information may include a BWP change indicator indicating that a BWP change is requested, the BWP change time point, and information indicating a new BWP.

Here, the BWP change time point may be one of a slot start point, a subframe start point, a TTI start point, a GP end point, and an uplink transmission area start point.

Here, each of the transmission and reception procedures of the first data and the transmission and reception procedure of the second data may be performed with the base station or another terminal.

In accordance with a second aspect of the present invention, there is provided a method of operating a terminal, the method comprising: receiving first BWP change information from a base station at BWP i; At the first BWP change time point indicated by the first BWP change information, if the procedure for transmitting / receiving data in the BWP i is not completed, the data of the data in the BWP i without changing the BWP even after the first BWP change time point. Performing a transmission / reception procedure; And changing the operation BWP of the terminal from the BWP i to the BWP j when the transmission and reception of the data is completed in the BWP i, wherein the BWP i and the BWP j are different BWPs, and i and j is a different integer.

Here, the operation BWP may be changed from the BWP i to the BWP j after a preset interval from the completion time of the data transmission and reception procedure.

Here, the operation BWP may be changed from the BWP i to the BWP j at the second BWP change time point indicated by the second BWP change information received from the base station.

Here, the first BWP change information may be received through at least one of an RRC message, a MAC CE, and a downlink control channel.

Here, the first BWP change information may be received through a downlink control channel together with resource allocation information for the data.

Here, the first BWP change information may include a BWP change indicator indicating that a BWP change is requested, the first BWP change time point, and information indicating a new BWP.

Here, the first BWP change time point is a start time of a slot, a start time of a subframe, a start time of a TTI, a end time of a GP, and a start time of a data channel (for example, a start time of a transmission area of downlink data). , Start time point of a transmission region of uplink data).

A method of operating a terminal according to a third embodiment of the present invention for achieving the above object comprises the steps of: receiving BWP change information from a base station in BWP i; Changing an operation BWP of the terminal from BWP i to BWP j even when a BWP change time indicated by the BWP change information is not completed, even when a procedure for transmitting and receiving first data in the BWP i is not completed; Performing a transmission / reception procedure of the first data in the BWP j; And when the transmission / reception procedure of the first data is completed, performing the transmission / reception procedure of the second data in the BWP j, wherein the BWP i and the BWP j are different BWPs, and i and j are different from each other. Is an integer.

Here, the BWP change information may be received through at least one of an RRC message, a MAC CE, and a downlink control channel.

Here, the BWP change information may be received through a downlink control channel together with resource allocation information for the data.

Here, the BWP change information may include a BWP change indicator indicating that a BWP change is requested, the BWP change time point, and information indicating a new BWP.

Here, the BWP change time point may be one of a slot start point, a subframe start point, a TTI start point, a GP end point, and an uplink transmission area start point.

According to the present invention, the bandwidth part (BWP) may be changed based on preset BWP changing methods (eg, BWP switching methods). For example, even when the procedure of transmitting / receiving the first data in the current operating BWP is not completed at the time of changing the BWP, the communication node (eg, the base station and the terminal) may change the operating BWP to the new BWP. In the new BWP, a second data transmission / reception procedure may be performed. In this case, the transmission delay of the second data in the new BWP can be prevented.

In addition, when the transmission and reception procedure of the second data in the new BWP is completed, the communication node may change the operation BWP (for example, the new BWP) to the previous operation BWP, and the transmission and reception procedure of the first data held in the previous operation BWP may be changed. Can be done. In this case, transmission reliability of the first data can be improved.

Alternatively, even when the procedure of transmitting / receiving the first data in the current operating BWP is not completed at the time of changing the BWP, the communication node (for example, the base station and the terminal) may change the operating BWP to the new BWP, In the BWP, a procedure of transmitting and receiving first data may be performed first, and after the procedure of transmitting and receiving first data is completed, a procedure of transmitting and receiving second data may be performed in a new BWP. In this case, transmission reliability of the first data can be improved.

Alternatively, if the data transmission and reception procedure of the current operation BWP is not completed at the time of BWP change, the communication node may perform the data transmission and reception procedure at the current operation BWP without changing the BWP, and the data transmission and reception procedure at the current operation BWP. When is completed, the operation BWP can be changed to a new BWP. In this case, transmission reliability of data can be improved.

1 is a conceptual diagram illustrating a first embodiment of a communication system.
2 is a block diagram showing a first embodiment of a communication node constituting a communication system.
3 is a conceptual diagram illustrating a first embodiment of a communication system supporting a low delay service.
4 is a conceptual diagram illustrating a first embodiment of a communication system supporting an ultra low delay service.
5 is a conceptual diagram illustrating a first embodiment of downlink transmission delay in a communication system.
6 is a conceptual diagram illustrating a first embodiment of an uplink transmission delay in a communication system.
7 is a conceptual diagram illustrating a delay in downlink / uplink transmission in a communication system.
8 is a conceptual diagram illustrating a BWP according to bandwidth adaptation in a communication system.
9A and 9B are conceptual views illustrating a first embodiment of a downlink communication procedure according to BWP change method 1 in an FDD communication system.
FIG. 10 is a conceptual diagram illustrating a first embodiment of an uplink communication procedure according to BWP change method 1 in an FDD communication system.
11A is a conceptual diagram illustrating a first embodiment of a downlink communication procedure according to BWP change method 1 in a TDD communication system.
11B is a conceptual diagram illustrating a first embodiment of an uplink communication procedure according to BWP change method 1 in a TDD communication system.
12A and 12B are conceptual views illustrating a first embodiment of a downlink communication procedure according to a BWP change method 2 in an FDD communication system.
FIG. 13 is a conceptual diagram illustrating a first embodiment of an uplink communication procedure according to a BWP change method 2 in an FDD communication system.
14A is a conceptual diagram illustrating a first embodiment of a downlink communication procedure according to a BWP change method 2 in a TDD communication system.
14B is a conceptual diagram illustrating a first embodiment of an uplink communication procedure according to a BWP change method 2 in a TDD communication system.
15A and 15B are conceptual views illustrating a first embodiment of a downlink communication procedure according to a BWP change method 3 in an FDD communication system.
16 is a conceptual diagram illustrating a first embodiment of an uplink communication procedure according to a BWP change method 3 in an FDD communication system.
17A is a conceptual diagram illustrating a first embodiment of a downlink communication procedure according to a BWP change method 3 in a TDD communication system.
17B is a conceptual diagram illustrating a first embodiment of an uplink communication procedure according to BWP change method 3 in a TDD communication system.
18 is a conceptual diagram illustrating a first embodiment of a data (re) transmission procedure according to the BWP change method 3 in the communication system.
19 is a conceptual diagram illustrating a second embodiment of a data (re) transmission procedure according to the BWP change method 3 in the communication system.
20A and 20B are conceptual views illustrating a first embodiment of a downlink communication procedure according to a BWP change method 4 in an FDD communication system.
21 is a conceptual diagram illustrating a first embodiment of an uplink communication procedure according to a BWP change method 4 in an FDD communication system.
FIG. 22 is a conceptual diagram illustrating a first embodiment of a downlink and uplink communication procedure according to a BWP change method 4 in a TDD communication system.
23A is a conceptual diagram illustrating a first embodiment of a method of transmitting / receiving an SS / PBCH block in a communication system.
23B is a conceptual diagram illustrating a second embodiment of a method of transmitting / receiving an SS / PBCH block in a communication system.
24 is a conceptual diagram illustrating a first embodiment of a bitmap indicating a new BWP in a communication system.
FIG. 25 is a conceptual diagram illustrating a first embodiment of a BWP switching time point for downlink communication in a communication system.
FIG. 26 is a conceptual diagram illustrating a first embodiment of a BWP switching time point for uplink communication in a communication system.

As the present invention allows for various changes and numerous embodiments, particular embodiments will be illustrated in the drawings and described in detail in the written description. However, this is not intended to limit the present invention to specific embodiments, it should be understood to include all modifications, equivalents, and substitutes included in the spirit and scope of the present invention.

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

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

The terminology used herein is for the purpose of describing particular example embodiments only and is not intended to be limiting of the present invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In this application, the terms "comprise" or "have" are intended to indicate that there is a feature, number, step, operation, component, part, or combination thereof described in the specification, and one or more other features. It is to be understood that the present invention does not exclude the possibility of the presence or the addition of numbers, steps, operations, components, components, or a combination thereof.

Unless defined otherwise, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art. Terms such as those defined in the commonly used dictionaries should be construed as having meanings consistent with the meanings in the context of the related art and shall not be construed in ideal or excessively formal meanings unless expressly defined in this application. Do not.

Hereinafter, with reference to the accompanying drawings, it will be described in detail a preferred embodiment of the present invention. In the following description of the present invention, the same reference numerals are used for the same elements in the drawings and redundant descriptions of the same elements will be omitted.

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

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

Referring to FIG. 1, the communication system 100 includes a plurality of communication nodes 110-1, 110-2, 110-3, 120-1, 120-2, 130-1, 130-2, 130-3, 130-4, 130-5, 130-6). The plurality of communication nodes are 4G communication (e.g., long term evolution (LTE), LTE-A (advanced)), 5G communication (e.g., new radio (NR)) as defined in the 3rd generation partnership project (3GPP) standard. ) And so on. 4G communication may be performed in a frequency band of 6 GHz or less, and 5G communication may be performed in a frequency band of 6 GHz or more as well as a frequency band of 6 GHz or less.

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

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

Meanwhile, a plurality of communication nodes 110-1, 110-2, 110-3, 120-1, 120-2, 130-1, 130-2, 130-3, and 130-constituting the communication system 100. 4, 130-5, 130-6) may each have the following structure.

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

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

However, each component included in the communication node 200 may be connected through a separate interface or a separate bus around the processor 210, instead of the common bus 270. For example, the processor 210 may be connected to at least one of the memory 220, the transceiver 230, the input interface device 240, the output interface device 250, and the storage device 260 through a dedicated interface. .

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

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

Here, each of the base stations 110-1, 110-2, 110-3, 120-1, and 120-2 is a NodeB, an evolved NodeB, a gNB, and a base transceiver station. ), A radio base station, a radio transceiver, a radio access station, an access point, an access node, or the like. Each of the terminals 130-1, 130-2, 130-3, 130-4, 130-5, and 130-6 may be a user equipment (UE), a terminal, an access terminal, or a mobile device. It may be referred to as a mobile terminal, a station, a subscriber station, a mobile station, a portable subscriber station, a node, a device, or the like.

Meanwhile, each of the base stations 110-1, 110-2, 110-3, 120-1, and 120-2 may operate in different frequency bands or may operate in the same frequency band. Each of the plurality of base stations 110-1, 110-2, 110-3, 120-1, and 120-2 may be connected to each other through an ideal backhaul link or a non-ideal backhaul link. It may exchange information with each other via an ideal backhaul link or a non-ideal backhaul link. Each of the base stations 110-1, 110-2, 110-3, 120-1, and 120-2 may be connected to the core network through an ideal backhaul link or a non-idal backhaul link. Each of the plurality of base stations 110-1, 110-2, 110-3, 120-1, and 120-2 receives a signal received from the core network, corresponding terminal 130-1, 130-2, 130-3, 130. -4, 130-5, 130-6, and the signal received from the corresponding terminal (130-1, 130-2, 130-3, 130-4, 130-5, 130-6) core network Can be sent to.

In addition, each of the plurality of base stations 110-1, 110-2, 110-3, 120-1, and 120-2 may transmit MIMO (eg, single user (SU) -MIMO, multi-user (MU)-). MIMO, massive MIMO, etc., coordinated multipoint (CoMP) transmission, carrier aggregation (CA) transmission, transmission in unlicensed band, device to device communication (D2D) (or ProSe ( proximity services). Here, each of the plurality of terminals 130-1, 130-2, 130-3, 130-4, 130-5, and 130-6 is a base station 110-1, 110-2, 110-3, 120-1 , 120-2), and operations supported by the base stations 110-1, 110-2, 110-3, 120-1, and 120-2. For example, the second base station 110-2 may transmit a signal to the fourth terminal 130-4 based on the SU-MIMO scheme, and the fourth terminal 130-4 may transmit the signal based on the SU-MIMO scheme. The signal may be received from the second base station 110-2. Alternatively, the second base station 110-2 may transmit a signal to the fourth terminal 130-4 and the fifth terminal 130-5 based on the MU-MIMO scheme, and the fourth terminal 130-4 may be used. And each of the fifth terminals 130-5 may receive a signal from the second base station 110-2 by the MU-MIMO scheme.

Each of the first base station 110-1, the second base station 110-2, and the third base station 110-3 may transmit a signal to the fourth terminal 130-4 based on a CoMP scheme, and a fourth The terminal 130-4 may receive a signal from the first base station 110-1, the second base station 110-2, and the third base station 110-3 by the CoMP scheme. Each of the base stations 110-1, 110-2, 110-3, 120-1, and 120-2 is a terminal 130-1, 130-2, 130-3, and 130-4 belonging to its own cell coverage. 130-5, 130-6) and a CA can transmit and receive a signal based on the method. Each of the first base station 110-1, the second base station 110-2, and the third base station 110-3 controls the D2D between the fourth terminal 130-4 and the fifth terminal 130-5. Each of the fourth terminal 130-4 and the fifth terminal 130-5 may perform D2D under the control of each of the second base station 110-2 and the third base station 110-3. .

Next, methods for reducing transmission delay in a communication system will be described. Even when the method (for example, the transmission or reception of a signal) is performed among the communication nodes is described, the corresponding second communication node corresponds to the method (for example, the method performed in the first communication node). For example, the reception or transmission of a signal) may be performed. That is, when the operation of the terminal is described, the base station corresponding thereto may perform an operation corresponding to the operation of the terminal. In contrast, when the operation of the base station is described, the terminal corresponding thereto may perform an operation corresponding to the operation of the base station.

In the following embodiments, a communication node providing an enhanced service may include an enhanced mobile broadband device (eMBB) (eg, a communication node transmitting and receiving high capacity data) and a low latency enabled (LL) device (eg, reducing transmission delay). Feature-enabled communication nodes), Coverage Enhanced (CE) devices (for example, communication nodes that provide the ability to provide improved transmission distances), or low complexity (LC) devices (for example, to improve complexity) Communication node).

The eMBB device, LL device, CE device, and LC device may be devices that provide enhanced service / reliability. The device providing enhanced service / reliability may be a base station, repeater, or terminal. In addition, devices that provide improved service / reliability may be mounted on vehicles, trains, unmanned aerial vehicles (eg, drones), manned aircraft, and the like. In addition to the eMBB device, LL device, CE device, and LC device, a communication node providing reliability may perform the following embodiments.

A device providing enhanced service / reliability may operate as a transmitting device, a receiving device, or a relay device. In the downlink communication procedure, a base station can operate as a transmitting device and a terminal can operate as a receiving device. In an uplink communication procedure, a base station can operate as a receiving device and a terminal can operate as a transmitting device.

Meanwhile, in a communication system that provides a high capacity data service (e.g., eMBB service), a high quality voice call service, a high quality video call service, a sharing service of accurate / fast data in a dense living space, and data (e.g., For example, a high speed transmission service of image data) may be provided.

In addition, the communication system may provide a real-time interaction-based convergence service (eg, a low delay service or an ultra low delay service). For example, real-time interaction-based convergence services include vehicle-to-vehicle (V2X) communications services, drone communications services, telemedicine services, industrial Internet of Things services, augmented reality services, and virtual reality services for autonomous driving. It may include. The low latency service may be performed as follows.

3 is a conceptual diagram illustrating a first embodiment of a communication system supporting a low delay service.

Referring to FIG. 3, the communication system may include a base station 300, a first terminal 310, and a second terminal 320. The first terminal 310 may be an actuator, and the second terminal 320 may be a sensor node or a utility node. The base station 300 may include a layer 1 (L1), a layer 2 (L2), a layer 3 (L3), and an application layer (APP). The base station 300 may be connected to a mobile edge cloud (MEC) server. Cross-layering may be applied to the layers included in the base station 300. Each of the first terminal 310 and the second terminal 320 may include a layer 1 (L1), a layer 2 (L2), and a layer 3 (L3). In addition, each of the first terminal 310 and the second terminal 320 may further include a layer that performs an embedded computing function. Cross-layering may be applied to the layers included in each of the first terminal 310 and the second terminal 320.

The radio transmission delay may be classified into a direct radio transmission delay and an indirect radio transmission delay. To support high transmission speed, high transmission efficiency, short transmission delay, and robust data transmission in communication between communication nodes (e.g., base station 300, first terminal 310, second terminal 320). However, a strict time delay may be required.

In a communication system providing an ultra low delay service, a radio transmission delay may include a transmission processing delay, a radio link delay, and a reception processing delay. The transmission processing delay may include a transmission delay from the application layer APP to layer 1 (L1) (eg, L2 processing delay) and L1 processing delay. The reception processing delay may include an L1 processing delay and a transmission delay from layer 1 (L1) to the application layer (APP) (eg, L2 processing delay). The L1 processing delay may be determined based on the processing performance of the baseband and the processing performance of the radio frequency (RF).

4 is a conceptual diagram illustrating a first embodiment of a communication system supporting an ultra low delay service.

Referring to FIG. 4, the communication system may include a base station and a terminal. The base station may include layer 1 (L1), layer 2 (L2), layer 3 (L3), and application layer (APP). The base station may be connected with the MEC server. The terminal may include layer 1 (L1), layer 2 (L2), and layer 3 (L3). In addition, the terminal may further include an application layer (APP). Cross-layering may be applied to the layers included in the terminal.

For example, the requirement of one-way wireless transmission delay between communication nodes (eg, base station, terminal) may be within 0.2 ms, and one-way end-to-end between communication nodes. The requirement for radio transmission delay may be within 0.25 ms. The requirement of wireless retransmission delay between communication nodes may be within 0.5 ms, and the requirement of handover delay may be within 2 ms.

Depending on the start / end time of signal processing, one-way radio transmission delay, one-way end-to-end radio transmission delay, and radio retransmission delay may be defined.

Unidirectional radio transmission delay: The unidirectional radio transmission delay may be a time from when the transmitting end receives data from layer 2 (L2) until the transmitting end transmits the data to layer 2 (L2). For example, the unidirectional radio transmission delay may be defined as the layer 1 (L1) processing time of the transmitting end (e.g., modulation processing time, encoding processing time), the transmission time over the radio link, and the layer 1 of the receiving end ( L1) may include a processing time (eg, a demodulation processing time, a decoding processing time).

Unidirectional end-to-end wireless transmission delay: The unidirectional end-to-end wireless transmission delay may be the time from the point at which the transmitting end receives data from the application layer (APP) until the receiving end passes the data to the application layer (APP). For example, the unidirectional end-to-end radio transmission delay may include layer 2/3 (L2 / 3) processing time (eg, data header generation time) of the transmitting end, layer 1 (L1) processing time of the transmitting end, and over the wireless link. Transmission time, layer 1 (L1) processing time of the receiving end, and layer 2/3 (L2 / 3) processing time of the receiving end.

Radio retransmission delay: The radio retransmission delay is a preparation time point for retransmission based on a feedback signal (for example, acknowledgment (ACK), negative ACK (ACK)) for the data from the transmission time of the data in layer 1 (L1) of the transmitting end. May be time to For example, the radio retransmission delay may include a transmission time of data over a wireless link, a processing time of data at a layer 1 (L1) of a receiver, a transmission time of a feedback signal through a wireless link, and a feedback at layer 1 (L1) of a transmitter. May include the processing time of the signal.

In order to provide an ultra low delay service to a terminal in a communication system, a radio access delay and a handover service delay may be defined.

-Wireless access delay: In order to reduce battery consumption of the terminal, the operating state of the terminal may be defined as an inactive state and an active state, and the wireless access delay transitions from the inactive state to the active state of the terminal. May be time to complete. An inactive state may be referred to as an idle state and an active state may be referred to as a connected state.

Handover Service Delay: The handover service delay may be a time (eg, a mobility interruption time (MIT)) when data transmission and reception are interrupted during the execution of the handover procedure.

Meanwhile, the radio transmission delay may be classified into a downlink transmission delay and an uplink transmission delay. The downlink transmission delay may be as follows.

5 is a conceptual diagram illustrating a first embodiment of downlink transmission delay in a communication system.

Referring to FIG. 5, the downlink transmission delay may be classified into a unidirectional radio transmission (TX) delay, a radio retransmission delay, a unidirectional end-to-end radio transmission delay, and a radio access delay. T _{DL, 1} to T _{DL, 11} may be defined as shown in Table 1 below. Table 1 may indicate a mapping relationship between a functional element and a delay in downlink transmission. In Table 1, "end-to-end" may indicate "one-way end-to-end wireless transmission delay" in FIG. 5, and "one-way" in Table 1 may indicate "one-way wireless transmission delay" in FIG. In Table 1, "retransmission" may indicate "wireless retransmission delay" of FIG. 5, and "connection" in Table 1 may indicate "wireless connection delay" of FIG.

Meanwhile, the uplink transmission delay may be as follows.

6 is a conceptual diagram illustrating a first embodiment of an uplink transmission delay in a communication system.

Referring to FIG. 6, an uplink transmission delay may be classified into a unidirectional radio transmission (TX) delay, a radio retransmission delay, a unidirectional end-to-end radio transmission delay, and a radio access delay. T _{UL, 0} to T _{UL, 16} may be defined as shown in Table 2 below. Table 2 may show a mapping relationship between a functional element and a delay in uplink transmission. In Table 2, "end-to-end" may indicate "one-way end-to-end wireless transmission delay" in FIG. 6, and "one-way" in Table 2 may indicate "one-way wireless transmission delay" in FIG. In Table 2, "retransmission" may indicate "wireless retransmission delay" of FIG. 6, and "connection" in Table 2 may indicate "wireless connection delay" of FIG.

7 is a conceptual diagram illustrating a delay in downlink / uplink transmission in a communication system.

Referring to FIG. 7, the base station may transmit a control channel (CTRL) including a downlink (DL) grant to the terminal, and may transmit a data channel including downlink data scheduled by the DL grant to the terminal. The terminal may receive a control channel (CTRL) from the base station, and may check the DL grant included in the control channel (CTRL). The UE may receive a data channel by monitoring time-frequency resources indicated by the DL grant, and may acquire downlink data included in the data channel. However, when the downlink data is not successfully decoded, the terminal may transmit a NACK to the base station in response to the downlink data. When the NACK is received from the terminal, the base station may retransmit downlink data.

In uplink transmission, the base station may transmit a control channel (CTRL) including an uplink (UL) grant to the terminal. The terminal may receive a control channel (CTRL) from the base station, and may check the UL grant included in the control channel (CTRL). The terminal may transmit a data channel including uplink data to the base station through time-frequency resources indicated by the UL grant. The base station may receive a data channel by monitoring the time-frequency resources indicated by the UL grant, and may obtain uplink data included in the data channel. The base station may transmit a feedback signal (eg, ACK or NACK) according to the decoding result of the uplink data to the terminal.

The meanings of K0 to K4 and N0 to N4 in FIG. 7 may be as shown in Table 3 below. In Table 3 below, delay units of K0 to K4 may be TTIs, and delay units of N0 to N4 may be symbols.

1 Delay reduction method and bandwidth improvement method according to bandwidth adaptation

The bandwidth part (BWP) may indicate some bandwidth among system bandwidths operated in one cell. Bandwidth adaptation may mean adjusting / changing the location / size of an operating bandwidth for data transmission and reception through a change in operating parameters (eg, numerology). Bandwidth adaptation may be performed as follows.

8 is a conceptual diagram illustrating a BWP according to bandwidth adaptation in a communication system.

Referring to FIG. 8, the operating bandwidth may be changed or switched to "BWP 1 → BWP 2 → BWP 3 → BWP 2 → BWP 1" according to bandwidth adaptation. For example, the size of BWP 1 on the frequency axis may be 40 MHz, and BWP 1 may be set according to subcarrier spacing 15 kHz. The magnitude of BWP 2 on the frequency axis may be 10 MHz, and BWP 2 may be set according to the subcarrier spacing 15 kHz. The size of BWP 3 on the frequency axis may be 20 MHz, and BWP 3 may be set according to the subcarrier spacing 60 kHz.

Bandwidth adaptation can be useful for power saving or bandwidth reduction for intermittent services, change of center frequency for flexible scheduling, and change of subcarrier spacing for low latency services.

The base station may include a radio resource control (RRC) message (eg, an RRC configuration message, an RRC control message), a medium access control (MAC) control element (eg, a sub header included in the MAC CE). ) And a downlink control channel (eg, downlink control information (DCI) included in a physical downlink control channel (PDCCH)) may be used to transmit BWP configuration information to the terminal. The terminal may receive the BWP configuration information from the base station, and may communicate with the base station in the BWP indicated by the BWP configuration information.

The BWP setting information may include operating parameters (e.g., operation BWP identifier (or identifiable index), information indicating the location of the operating bandwidth, information indicating the size of the operating bandwidth, subcarrier interval applied to the operating bandwidth, CP ( cyclic prefix), numerology), transmission time and feedback time for (re) transmission of data, reception time of downlink control channel, time information (e.g., timing, frame duration) to which the current BWP is applied, It may include one or more of setting information of a new BWP (eg, next BWP), and a time interval (eg, timing, frame interval) to which the new BWP is applied.

The BWP change or switch (e.g., change or switch BWP for data (re) transmission) is at the point indicated by the information elements (e.g., change or switch point, new BWP index) included in the BWP configuration information. Can be performed. Alternatively, the BWP change or switching may be performed after a preset duration (eg, n slots or subframes) from the time point of receiving the BWP configuration information. Here, n may be an integer of 0 or more. "BWP change" may mean "BWP switching."

In addition, the terminal may change the BWP based on a preset BWP change pattern. For example, the UE may transmit and receive data with the base station in BWP2 after changing the operation BWP from BWP1 to BWP2 according to the BWP change pattern, and change the operation BWP from BWP2 to BWP3 according to the BWP change pattern and then change the base station from BWP3 to the base station. You can send and receive data. The BWP change pattern may be included in the BWP configuration information.

Meanwhile, the base station may set one or more BWP configuration information and corresponding BWP change information (eg, BWP change pattern) between the base station and the terminal. If the terminal receives the BWP change information (ie, BWP change pattern) from the base station, the terminal may override the new BWP change information to the previous BWP change information. The UE may perform a BWP change related operation based on the most recently received BWP change information.

On the other hand, when the BWP change time point overlaps with the transmission time point of the signal (eg, a signal transmitted according to a preset period or timing (eg, synchronization signal, reference signal, feedback on data transmission, retransmission data)), The terminal may not successfully receive the signal. We will need a way to change the BWP to solve this problem.

For example, when the base station transmits a synchronization signal in BWP 3, the terminal receives the corresponding synchronization signal in BWP 3 to obtain or maintain synchronization with the base station. Even when data is transmitted and received at BWP 2, the UE should change the operation BWP from BWP 2 to BWP 3 before the synchronization signal is received in order to receive the synchronization signal. However, if the data retransmission procedure is not completed in BWP 2 before the synchronization signal is received due to data retransmission, the UE may not successfully receive data when the operation BWP is changed from BWP 2 to BWP 3. We will need a way to change the BWP to solve this problem.

1.1 How to change BWP for data (re) transmission

A combination of one or more of the BWP change methods 1-4 described below can be used for the BWP change. For example, the BWP change method may vary according to a specific BWP, a specific terminal, a specific service, and specific requirements. The base station may transmit information indicating one or more BWP change methods supported by the base station among the BWP change methods 1-4 to the UE through at least one of an RRC message, a MAC CE, and a downlink control channel. The terminal may receive information indicating one or more BWP change methods supported by the base station from the base station and communicate using one or more BWP change methods supported by the base station (eg, downlink communication, uplink communication). , Sidelink (e-communication, communication in an unlicensed band) can be performed.

1.1.1 How to change BWP 1

The communication procedure may be terminated at the BWP change time regardless of whether data transmission or reception is completed. The communication node (for example, the base station and the terminal) may change the current operation BWP to a new BWP at the time of BWP change, and may perform a procedure of transmitting and receiving new data in the new operation BWP. That is, even when the transmission and reception of data is not completed, the communication node may not expect the data to be (re) transmitted, and perform the data transmission / reception operation (eg, buffering operation for the received data) in the previous operation BWP. You can't.

9A and 9B are conceptual views illustrating a first embodiment of a downlink communication procedure according to BWP change method 1 in a frequency division duplex (FDD) communication system.

9A and 9B, BWP i may be an UL BWP and BWP k and l may be DL BWP. Each of BWP i, k, and l may be a different BWP. On the time axis, the last slots shown in FIG. 9A may be contiguous with the start slots shown in FIG. 9B. That is, the HARQ response to the data DATA indicated by ① in FIG. 9A may be the FB indicated by ① in FIG. 9B. T _{DL, 3} , T _{DL, 4} , T _{DL, 5} , T _{DL, 6} , T _{DL, 7} , T _{DL, 8} , T _{DL, 9} , T _{DL, 10} , and T _{DL, 11} are each shown in FIG. 5. It can correspond to the illustrated T _{DL, 3} , T _{DL, 4} , T _{DL, 5} , T _{DL, 6} , T _{DL, 7} , T _{DL, 8} , T _{DL, 9} , T _{DL, 10} , and T _{DL, 11} have. The base station and the terminal may perform downlink communication in BWP l. When a change from BWP 1 to BWP k is required, the base station may transmit BWP change information indicating a change from BWP 1 to BWP k through at least one of an RRC message, a MAC CE, and a downlink control channel. For example, BWP change information may be included in DCI format 1_1.

The BWP change information includes information requesting a BWP change (hereinafter referred to as "BWP change indicator"), information indicating when to change the BWP (hereinafter referred to as "BWP change point"), and information indicating a new BWP ( For example, it may include one or more information from a BWP identifier (ID), a BWP index, a bitmap, and a BWP change pattern. The BWP change time point may include a start time of a slot that first arrives after transmission of a downlink control channel (eg, DCI) including BWP change information, a start time of a subframe, a start time of a transmission time interval (TTI), and a GP. It may be set to the end of the guard period, the start of the uplink transmission region, or the transmission of the downlink control channel.

The UE may receive the BWP change information from the base station by monitoring the downlink control channel, and may confirm that a change (for example, change from BWP 1 to BWP k) of the operation BWP is requested based on the BWP change information. . In addition, the terminal may check the BWP change time point based on the BWP change information. When the BWP change information is received, the terminal may transmit a response (for example, ACK or NACK) to the base station for the BWP change information. When an acknowledgment (ACK) for the BWP change information is received from the terminal, the base station may determine that the BWP change information has been successfully received at the terminal. If the base station does not receive an acknowledgment (ACK) for the BWP change information from the terminal, receives a negative response (NACK), or does not receive a response within a predefined time, the base station is the BWP change information It may be regarded as not received at the terminal. In this case, the base station may request BWP change by retransmitting BWP change information or transmitting new BWP change information to the UE. On the other hand, when a plurality of BWP change information is received, the terminal may change the BWP based on the information indicated by the most recent BWP change information.

The base station and the terminal may change the operation BWP at a time point set by the base station or a preset time point. For example, when the operation BWP is changed from BWP l to BWP k, the base station and the terminal may stop the downlink communication procedure from the transmission and reception time of the BWP change information to the BWP change time, and the operation BWP is the BWP k at BWP l. After changing to BWP k can perform a new downlink communication procedure.

Even when the procedure for transmitting / receiving data in BWP l is not completed, the UE may change the operation BWP from BWP l to BWP k. For example, when a negative ACK (NACK) for downlink data is transmitted to the base station at BWP l, the UE may not expect to retransmit the downlink data at BWP l, and the operation BWP is changed from BWP k to BWP k. Can be changed to In addition, since the UE does not expect the downlink data to be retransmitted in the BWP l, the terminal may stop the corresponding downlink communication operation (for example, the buffering operation). In this case, the UE may store data (for example, soft bits, log likelihood ratios) in the soft buffer and information for receiving the corresponding data (for example, HARQ process ID, redundancy version), and NDI (new). data indicator) can be dropped. The base station may terminate the transmission of the data, and may drop the data stored in the soft buffer and information for retransmission (eg, HARQ process ID, RV, NDI) for the data retransmission.

FIG. 10 is a conceptual diagram illustrating a first embodiment of an uplink communication procedure according to BWP change method 1 in an FDD communication system.

Referring to FIG. 10, BWP i and j may be UL BWP, and BWP 1 may be DL BWP. Each of BWP i, j, and l may be a different BWP. T _{UL, 5} , T _{UL, 6} , T _{UL, 7} , T _{UL, 8} , T _{UL, 9} , T _{UL, 10} , T _{UL, 11} , T _{UL, 12} , and T _{UL, 13} are shown in FIG. 6, respectively. It can correspond to the illustrated T _{UL, 5} , T _{UL, 6} , T _{UL, 7} , T _{UL, 8} , T _{UL, 9} , T _{UL, 10} , T _{UL, 11} , T _{UL, 12} , and T _{UL, 13} have. The base station and the terminal may perform uplink communication in BWP i. When a change from BWP i to BWP j is required, the base station may transmit BWP change information indicating a change from BWP i to BWP j through at least one of an RRC message, a MAC CE, and a downlink control channel. For example, BWP change information may be included in DCI format 1_1.

The BWP change information may include one or more of a BWP change indicator, a BWP change time point, and information indicating a new BWP (eg, BWP ID, BWP index, bitmap, BWP change pattern). The BWP change time point is a start point of a slot, a start point of a subframe, a start point of a TTI, an end point of a GP, and an uplink after the transmission of a downlink control channel (eg, DCI) including BWP change information. It may be set to the start time of the link transmission region or the transmission time of the downlink control channel.

The UE may receive the BWP change information from the base station by monitoring the downlink control channel, and may confirm that a change (eg, change from BWP i to BWP j) of the operation BWP is requested based on the BWP change information. . In addition, the terminal may check the BWP change time point based on the BWP change information. When the BWP change information is received, the terminal may transmit a response (for example, ACK or NACK) to the base station for the BWP change information. When an acknowledgment (ACK) for the BWP change information is received from the terminal, the base station may determine that the BWP change information has been successfully received at the terminal. If the base station does not receive an acknowledgment (ACK) for the BWP change information from the terminal, receives a negative response (NACK), or does not receive a response within a predefined time, the base station is the BWP change information It may be regarded as not received at the terminal. In this case, the base station may request BWP change by retransmitting BWP change information or transmitting new BWP change information to the UE. On the other hand, when a plurality of BWP change information is received, the terminal may change the BWP based on the information indicated by the most recent BWP change information.

The base station and the terminal may change the operation BWP at a time point set by the base station or a preset time point. For example, when the operation BWP is changed from BWP i to BWP j, the base station and the terminal may stop the uplink communication procedure from the transmission and reception time of the BWP change information to the BWP change time, and the operation BWP is the BWP i BWP j After changing to BWP j can perform a new uplink communication procedure.

Even when the procedure for transmitting / receiving data in the BWP i is not completed, the terminal may change the operation BWP from BWP i to BWP j. For example, when data that is not transmitted to the base station in the BWP i exists in the terminal (for example, when a NACK for uplink data is received from the base station, the terminal of the resource allocation information for retransmission of the uplink data In case of expecting reception, or when retransmission of a hybrid automatic repeat request (HARQ) response to downlink data is required, the terminal may transmit a corresponding uplink communication procedure (for example, retransmission of uplink data, retransmission of HARQ response). The operation BWP can be changed from BWP i to BWP j without performing.

Since the base station does not expect the uplink data to be retransmitted in the BWP i, the base station may stop the corresponding uplink communication operation (for example, the buffering operation). In this case, the base station receives the data stored in the soft buffer (eg, soft bits, LLR) and information for receiving the corresponding data and reassigning uplink data to the corresponding terminal (eg, HARQ process ID, RV, NDI). ) Can be discarded. The terminal may discard the data (eg, soft bits) stored in the soft buffer for transmission and the information (eg, HARQ process ID, RV, NDI) for transmission of the corresponding data.

FIG. 11A is a conceptual diagram illustrating a first embodiment of a downlink communication procedure according to BWP change method 1 in a time division duplex (TDD) communication system, and FIG. 11B is an uplink communication procedure according to BWP change method 1 in a TDD communication system. A conceptual diagram showing a first embodiment of the present invention.

11A and 11B, the subframe may be a self-contained subframe. The frame (eg, subframe) structure may be determined according to downlink control / data channel transmission, downlink data configuration, and uplink data configuration. Each of BWP i and j may be a different BWP.

The downlink communication procedure illustrated in FIG. 11A may be performed the same as or similar to the downlink communication procedure illustrated in FIG. 9A. For example, since the UE does not expect to perform retransmission of the downlink data, the operation BWP may be changed from BWP i to BWP j regardless of whether the current downlink communication procedure is completed. In addition, the terminal may stop the corresponding communication procedure (eg, buffering operation of the downlink data), and may perform a new downlink communication procedure with the base station in BWP j. Here, T _{DL, 3} , T _{DL, 4} , T _{DL, 5} , T _{DL, 6} , T _{DL, 7} , T _{DL, 8} , T _{DL, 9} , T _{DL, 10} , and T _{DL, 11} respectively T _{DL, 3} , T _{DL, 4} , T _{DL, 5} , T _{DL, 6} , T _{DL, 7} , T _{DL, 8} , T _{DL, 9} , T _{DL, 10} , and T _{DL, 11 shown} in 5 It can respond.

The uplink communication procedure illustrated in FIG. 11B may be performed the same as or similar to the uplink communication procedure illustrated in FIG. 10. For example, the UE may stop the uplink communication procedure (for example, retransmission of uplink data, retransmission of HARQ response) in BWP j, and change operation BWP from BWP j to BWP i at the time of BWP change. have. Since the base station does not expect the uplink data to be retransmitted in BWP j, the base station may stop the corresponding communication operation (for example, buffering operation in BWP j). Here, T _{UL, 5} , T _{UL, 6} , T _{UL, 7} , T _{UL, 8} , T _{UL, 9} , T _{UL, 10} , T _{UL, 11} , T _{UL, 12} , and T _{UL, 13} are shown in FIG. T _{UL, 5} , T _{UL, 6} , T _{UL, 7} , T _{UL, 8} , T _{UL, 9} , T _{UL, 10} , T _{UL, 11} , T _{UL, 12} , and T _{UL, 13 shown} in 6 It can respond.

Meanwhile, according to the BWP change method 1 described above, the BWP may be changed regardless of whether the current downlink / uplink communication procedure is completed. Therefore, implementation complexity (eg, the complexity of the buffering operation) for BWP change may not increase. However, when the BWP is changed while the downlink / uplink communication procedure is not completed, a transmission delay of data may occur, and transmission reliability of the communication system may be degraded.

1.1.2 BWP  Change method 2

If data transmission and reception is not completed at the time of BWP change, the communication node (for example, the base station and the terminal) may change the current BWP to a new BWP after completing the transmission and reception of data. In this case, the BWP change may be delayed.

12A and 12B are conceptual views illustrating a first embodiment of a downlink communication procedure according to a BWP change method 2 in an FDD communication system.

12A and 12B, BWP i may be an UL BWP, and BWP k and l may be DL BWP. Each of BWP i, k, and l may be a different BWP. On the time axis, the last slots shown in FIG. 12A may be contiguous with the start slots shown in FIG. 12B. That is, ① shown in FIG. 12A may be continuous with ① shown in FIG. 12B, and the HARQ response to data DATA indicated by ② shown in FIG. 12A may be FB indicated by ② in FIG. 12B. And (3) shown in FIG. 12A may be continuous with (3) shown in FIG. 12B.

T _{DL, 3} , T _{DL, 4} , T _{DL, 5} , T _{DL, 6} , T _{DL, 7} , T _{DL, 8} , T _{DL, 9} , T _{DL, 10} , and T _{DL, 11} are each shown in FIG. 5. It can correspond to the illustrated T _{DL, 3} , T _{DL, 4} , T _{DL, 5} , T _{DL, 6} , T _{DL, 7} , T _{DL, 8} , T _{DL, 9} , T _{DL, 10} , and T _{DL, 11} have. The base station and the terminal may perform downlink communication in BWP l. If a change from BWP l to BWP k is required, the base station may transmit BWP change information indicating a change in BWP (for example, from BWP l to BWP k) at least one of an RRC message, a MAC CE, and a downlink control channel. The above transmission is possible. For example, BWP change information may be included in DCI format 1_1. The BWP change information may include one or more of a BWP change indicator, a BWP change time point, and information indicating a new BWP (eg, BWP ID, BWP index, bitmap, BWP change pattern).

The UE may receive BWP change information (for example, change from BWP l to BWP k) by monitoring the downlink control channel, and request that a change from BWP l to BWP k is requested based on the BWP change information. You can check it. In addition, the terminal may check the BWP change time point based on the BWP change information. When the BWP change information is received, the terminal may transmit a response (for example, ACK or NACK) to the base station for the BWP change information. When an acknowledgment (ACK) for the BWP change information is received from the terminal, the base station may determine that the BWP change information has been successfully received at the terminal. If the base station does not receive an acknowledgment (ACK) for the BWP change information from the terminal, receives a negative response (NACK), or does not receive a response within a predefined time, the base station is the BWP change information It may be regarded as not received at the terminal. In this case, the base station may request BWP change by retransmitting BWP change information or transmitting new BWP change information to the UE. On the other hand, when a plurality of BWP change information is received, the terminal may change the BWP based on the information indicated by the most recent BWP change information.

The base station and the terminal may change the operation BWP at a time point set by the base station or a preset time point. For example, when the operation BWP is changed from BWP l to BWP k, when the downlink communication procedure at BWP l is not completed at the time of BWP change (for example, when a retransmission procedure of downlink data is performed). The base station and the terminal may not change the operation BWP from BWP l to BWP k at the time of BWP change. When the corresponding downlink communication procedure is completed in BWP l or when a predetermined change time expires regardless of the transmission result, the base station and the UE may change the operation BWP from BWP l to BWP k and a new downlink in BWP k. The communication procedure can be performed. That is, the BWP change may be delayed.

Here, the base station may retransmit at least one or more of the RRC message, MAC CE, and downlink control channel including the BWP change information after the downlink communication procedure is completed in the BWP l, the terminal after receiving the BWP change information The operation BWP can be changed from BWP l to BWP k. Alternatively, a communication interval (or timer) for completing transmission of downlink data between the base station and the terminal may be set in advance. In this case, the base station and the terminal may complete the downlink communication procedure in a preset communication period (or time), and change the operation BWP from BWP l to BWP k after the preset communication period (or timer) expires. . Alternatively, the base station and the terminal may change the operation BWP from BWP 1 to BWP k after a preset duration from the completion time of the downlink communication procedure. On the other hand, when a plurality of BWP change information is received, the terminal may change the BWP based on the information indicated by the most recent BWP change information.

According to "BWP change method 2", the BWP change may be delayed in the downlink transmission procedure. If the priority of the signal transmitted at the new BWP (eg BWP k) is higher than the priority of the signal transmitted at the current BWP (eg BWP l), then at the current BWP (eg BWP l) When the number of HARQ retransmissions is equal to the maximum number of retransmissions, or when the HARQ retransmission timer expires at the current BWP (for example, BWP l), the base station and the terminal are assigned to "BWP change method 1" instead of "BWP change method 2". Accordingly, the downlink transmission procedure can be stopped at the current BWP (eg, BWP l), and at the time of BWP change, the operation BWP is changed to a new BWP (eg, BWP k) at the current BWP (eg, BWP l). Can be changed to Here, the priority of a signal (eg, a synchronization signal, a reference signal, feedback on data transmission, system information) transmitted according to a specific period or timing may be higher than the priority of the data signal.

FIG. 13 is a conceptual diagram illustrating a first embodiment of an uplink communication procedure according to a BWP change method 2 in an FDD communication system.

Referring to FIG. 13, BWP i and j may be UL BWP, and BWP 1 may be DL BWP. Each of BWP i, j, and l may be a different BWP. T _{UL, 5} , T _{UL, 6} , T _{UL, 7} , T _{UL, 8} , T _{UL, 9} , T _{UL, 10} , T _{UL, 11} , T _{UL, 12} , and T _{UL, 13} are shown in FIG. 6, respectively. It can correspond to the illustrated T _{UL, 5} , T _{UL, 6} , T _{UL, 7} , T _{UL, 8} , T _{UL, 9} , T _{UL, 10} , T _{UL, 11} , T _{UL, 12} , and T _{UL, 13} have. The base station and the terminal may perform uplink communication in BWP i. If a change from BWP i to BWP j is required, the base station may transmit BWP change information indicating a change in BWP (for example, from BWP i to BWP j) at least one of an RRC message, a MAC CE, and a downlink control channel. The above transmission is possible. For example, BWP change information may be included in DCI format 1_1. The BWP change information may include one or more of a BWP change indicator, a BWP change time point, and information indicating a new BWP (eg, BWP ID, BWP index, bitmap, BWP change pattern).

The UE may receive BWP change information from the base station by monitoring the downlink control channel, and may confirm that a change from BWP i to BWP j is requested based on the BWP change information. In addition, the terminal may check the BWP change time point based on the BWP change information. When the BWP change information is received, the terminal may transmit a response (for example, ACK or NACK) to the base station for the BWP change information. When an acknowledgment (ACK) for the BWP change information is received from the terminal, the base station may determine that the BWP change information has been successfully received at the terminal. If the base station does not receive an acknowledgment (ACK) for the BWP change information from the terminal, receives a negative response (NACK), or does not receive a response within a predefined time, the base station is the BWP change information It may be regarded as not received at the terminal. In this case, the base station may request BWP change by retransmitting BWP change information or transmitting new BWP change information to the UE. On the other hand, when a plurality of BWP change information is received, the terminal may change the BWP based on the information indicated by the most recent BWP change information.

The base station and the terminal may change the operation BWP at a time point set by the base station or a preset time point. For example, when the operation BWP is changed from BWP i to BWP j, when data is not transmitted from the BWP i to the base station at the time of BWP change, for example, a NACK for uplink data is transmitted from the base station. When received, when the terminal expects to receive resource allocation information for retransmission of uplink data, or when retransmission of HARQ response for downlink data is required), the base station and the terminal perform the operation BWP at the time of BWP change. You can not change from i to BWP j. In this case, the base station and the UE may perform the uplink retransmission procedure for the corresponding data in BWP i, and the operation BWP is performed when the predetermined change time expires regardless of the completion of the uplink retransmission procedure or the transmission result. It is possible to change from i to BWP j, and to perform a new uplink communication procedure in BWP j. That is, the BWP change may be delayed.

Here, the base station may retransmit at least one or more of the RRC message, MAC CE, and downlink control channel including the BWP change information after the uplink communication procedure is completed in the BWP i, the terminal after receiving the BWP change information Operation BWP can be changed from BWP i to BWP j. Alternatively, a communication interval (or timer) for completing transmission of uplink data between the base station and the terminal may be preset. In this case, the base station and the terminal may complete the uplink communication procedure in a preset communication period (or time), and change the operation BWP from BWP i to BWP j after the preset communication period (or timer) expires. . Alternatively, the base station and the terminal may change the operation BWP from BWP i to BWP j after a preset duration from the completion time of the uplink communication procedure. On the other hand, when a plurality of BWP change information is received, the terminal may change the BWP based on the information indicated by the most recent BWP change information.

According to "BWP change method 2", the BWP change may be delayed in the uplink transmission procedure. If the priority of the signal transmitted at the new BWP (eg BWP j) is higher than the priority of the signal transmitted at the current BWP (eg BWP i), then at the current BWP (eg BWP i) If the number of HARQ retransmissions is equal to the maximum number of retransmissions, or if the HARQ retransmission timer expires at the current BWP (for example, BWP i), the base station and the terminal are assigned to "BWP change method 1" instead of "BWP change method 2". Accordingly, the uplink transmission procedure may be stopped at the current BWP (eg, BWP i), and at the time of BWP change, the operation BWP is changed to a new BWP (eg, BWP j) at the current BWP (eg, BWP i). Can be changed to Here, the priority of a signal (eg, a synchronization signal, a reference signal, feedback on data transmission, system information) transmitted according to a specific period or timing may be higher than the priority of the data signal.

FIG. 14A is a conceptual diagram illustrating a first embodiment of a downlink communication procedure according to a BWP change method 2 in a TDD communication system, and FIG. 14B is a first embodiment of an uplink communication procedure according to a BWP change method 2 in a TDD communication system. A conceptual diagram showing the.

14A and 14B, the subframe may be an SC subframe. The frame (eg, subframe) structure may be determined according to downlink control / data channel transmission, downlink data configuration, and uplink data configuration. Each of BWP i and j may be a different BWP.

The downlink communication procedure illustrated in FIG. 14A may be performed the same as or similar to the downlink communication procedure illustrated in FIG. 12A. For example, the base station and the terminal may not change the operation BWP from BWP i to BWP j when the downlink transmission procedure is not completed at the time of BWP change. In this case, when the downlink transmission procedure is completed in the BWP i or the predetermined change time expires regardless of the transmission result (for example, when the number of HARQ retransmissions in the BWP i is equal to the maximum number of transmissions, or in the BWP i When the HARQ retransmission timer expires), the base station and the terminal may change the operation BWP from BWP i to BWP j. Therefore, the BWP change may be delayed. Here, T _{DL, 3} , T _{DL, 4} , T _{DL, 5} , T _{DL, 6} , T _{DL, 7} , T _{DL, 8} , T _{DL, 9} , T _{DL, 10} , and T _{DL, 11} respectively T _{DL, 3} , T _{DL, 4} , T _{DL, 5} , T _{DL, 6} , T _{DL, 7} , T _{DL, 8} , T _{DL, 9} , T _{DL, 10} , and T _{DL, 11 shown} in 5 It can respond.

The uplink communication procedure illustrated in FIG. 14B may be performed the same as or similar to the uplink communication procedure illustrated in FIG. 13. For example, the base station and the terminal may not change the operation BWP from BWP i to BWP j when the uplink transmission procedure is not completed at the time of BWP change. In this case, the base station and the terminal may perform an uplink retransmission procedure for the corresponding data, and when the uplink retransmission procedure is completed, the operation BWP may be changed from BWP i to a new BWP j, and a new uplink in the new BWP j The communication procedure can be performed. That is, the BWP change may be delayed. Here, T _{UL, 5} , T _{UL, 6} , T _{UL, 7} , T _{UL, 8} , T _{UL, 9} , T _{UL, 10} , T _{UL, 11} , T _{UL, 12} , and T _{UL, 13} are shown in FIG. T _{UL, 5} , T _{UL, 6} , T _{UL, 7} , T _{UL, 8} , T _{UL, 9} , T _{UL, 10} , T _{UL, 11} , T _{UL, 12} , and T _{UL, 13 shown} in 6 It can respond.

After the downlink / uplink communication procedure is completed in the BWP i, the base station may retransmit at least one or more of an RRC message, MAC CE, and downlink control channel including the BWP change information, and the terminal receives the BWP change information. You can later change the operation BWP from BWP i to BWP j. Alternatively, a communication period (or a timer) for completing transmission of downlink / uplink data between the base station and the terminal may be preset. In this case, the base station and the terminal may complete the downlink / uplink communication procedure in the preset communication period, and change the operation BWP from BWP i to BWP j after the preset communication period expires. Alternatively, the base station and the terminal may change the operation BWP from BWP i to BWP j after a preset duration from the completion point of the downlink / uplink communication procedure. On the other hand, when a plurality of BWP change information is received, the terminal may change the BWP based on the information indicated by the most recent BWP change information.

In addition, when the BWP change information is received, the terminal may transmit a response (for example, ACK or NACK) to the base station for the BWP change information. When an acknowledgment (ACK) for the BWP change information is received from the terminal, the base station may determine that the BWP change information has been successfully received at the terminal. If the base station does not receive an acknowledgment (ACK) for the BWP change information from the terminal, receives a negative response (NACK), or does not receive a response within a predefined time, the base station is the BWP change information It may be regarded as not received at the terminal. In this case, the base station may request BWP change by retransmitting BWP change information or transmitting new BWP change information to the UE. On the other hand, when a plurality of BWP change information is received, the terminal may change the BWP based on the information indicated by the most recent BWP change information.

Meanwhile, according to the BWP change method 2 described above, a data transmission delay may not occur, and reliability of a communication system may not be degraded. However, the BWP change may be delayed, and a transmission delay of data (for example, data having a high priority) may occur in the new BWP.

1.1.3 BWP  Change method 3

Not only when the transmission and reception of data is completed at the time of BWP change but also when the transmission and reception of data are not completed, the communication node (for example, the base station and the terminal) may select an operation BWP (for example, BWP l) and a new BWP (eg, For example, it may be changed to BWP k), and a new data transmission / reception procedure may be performed at BWP k. However, when the transmission and reception of data in BWP l is not completed, the communication node may suspend (eg, suspend) a data transmission / reception procedure in BWP l from the time of BWP change. In this case, data stored in the soft buffer of the communication node (eg, soft bits, LLR) and information for resuming data transmission and reception (eg, HARQ process ID, RV, NDI) may be maintained without being discarded. When the new data transmission / reception procedure is completed at BWP k, the communication node may change the operation BWP from BWP k to BWP l, and resume the transmission / reception procedure of the data held at BWP l.

15A and 15B are conceptual views illustrating a first embodiment of a downlink communication procedure according to a BWP change method 3 in an FDD communication system.

15A and 15B, BWP i may be an UL BWP, and BWP k and l may be DL BWP. Each of BWP i, k, and l may be a different BWP. In the time axis, the last slots shown in FIG. 15A may be contiguous with the start slots shown in FIG. 15B. That is, resource allocation information for retransmission according to FB (eg, NACK) indicated by ① in FIG. 15A may be transmitted through the control channel CTRL indicated by ① in FIG. 15B. T _{DL, 3} , T _{DL, 4} , T _{DL, 5} , T _{DL, 6} , T _{DL, 7} , T _{DL, 8} , T _{DL, 9} , T _{DL, 10} , and T _{DL, 11} are each shown in FIG. 5. It can correspond to the illustrated T _{DL, 3} , T _{DL, 4} , T _{DL, 5} , T _{DL, 6} , T _{DL, 7} , T _{DL, 8} , T _{DL, 9} , T _{DL, 10} , and T _{DL, 11} have. The base station and the terminal may perform downlink communication in BWP l. If a change from BWP l to BWP k is required, the base station may transmit BWP change information indicating a change in BWP (for example, from BWP l to BWP k) at least one of an RRC message, a MAC CE, or a downlink control channel. The above transmission is possible. For example, BWP change information may be included in DCI format 1_1.

The BWP change information may include one or more of a BWP change indicator, a BWP change time point, and information indicating a new BWP (eg, BWP ID, BWP index, bitmap, BWP change pattern). The BWP change time point is a start point of a slot, a start point of a subframe, a start point of a TTI, an end point of a GP, and an uplink after the transmission of a downlink control channel (eg, DCI) including BWP change information. It may be set to the start time of the link transmission region or the transmission time of the downlink control channel.

The UE may receive BWP change information (for example, change from BWP l to BWP k) by monitoring the control channel and confirm that a change from BWP l to BWP k is requested based on the BWP change information. have. In addition, the terminal may check the BWP change time point based on the BWP change information. When the BWP change information is received, the terminal may transmit a response (for example, ACK or NACK) to the base station for the BWP change information. When an acknowledgment (ACK) for the BWP change information is received from the terminal, the base station may determine that the BWP change information has been successfully received at the terminal. If the base station does not receive an acknowledgment (ACK) for the BWP change information from the terminal, receives a negative response (NACK), or does not receive a response within a predefined time, the base station is the BWP change information It may be regarded as not received at the terminal. In this case, the base station may request BWP change by retransmitting BWP change information or transmitting new BWP change information to the UE. On the other hand, when a plurality of BWP change information is received, the terminal may change the BWP based on the information indicated by the most recent BWP change information.

The base station and the terminal may change the operation BWP at a time point set by the base station or a preset time point. For example, when the operation BWP is to be changed from BWP l to BWP k, the base station and the terminal may suspend (eg, suspend) the downlink communication procedure from the time of transmitting and receiving the BWP change information to the time of the BWP change. After BWP l is changed to BWP k, a new downlink communication procedure may be performed at BWP k.

Even when the procedure for transmitting / receiving data in BWP l is not completed, the UE may change the operation BWP from BWP l to BWP k. For example, when the NACK for the downlink data is transmitted from the BWP l to the base station, the terminal may change the operation BWP from BWP l to BWP k. In this case, the UE may expect that the downlink communication procedure held in BWP 1 will be resumed after the procedure for transmitting and receiving new data at BWP k is completed. Accordingly, the terminal may maintain the data stored in the soft buffer (eg, soft bit, LLR) and information for resuming data transmission and reception (eg, HARQ process ID, RV, NDI) without discarding it.

If the data transmission / reception procedure is not completed at BWP l, and the data transmission / reception procedure is completed at BWP k after the change from BWP l to BWP k, the base station changes the BWP change (for example, from BWP k to BWP l). The indicating BWP change information may be transmitted through at least one of an RRC message, a MAC CE, and a downlink control channel. The BWP change information may include one or more of a BWP change indicator, a BWP change time point, and information indicating a new BWP (eg, BWP ID, BWP index, bitmap, BWP change pattern).

The UE may receive BWP change information from the base station by monitoring the downlink control channel, and may confirm that a change from BWP k to BWP l is requested based on the BWP change information. In addition, the terminal may check the BWP change time point based on the BWP change information. When the BWP change information is received, the terminal may transmit a response (for example, ACK or NACK) to the base station for the BWP change information. When an acknowledgment (ACK) for the BWP change information is received from the terminal, the base station may determine that the BWP change information has been successfully received at the terminal. If the base station does not receive an acknowledgment (ACK) for the BWP change information from the terminal, receives a negative response (NACK), or does not receive a response within a predefined time, the base station is the BWP change information It may be regarded as not received at the terminal. In this case, the base station may request BWP change by retransmitting BWP change information or transmitting new BWP change information to the UE. On the other hand, when a plurality of BWP change information is received, the terminal may change the BWP based on the information indicated by the most recent BWP change information.

The base station and the terminal may change the operation BWP from BWP k to BWP l at the time of BWP change, and resume the transmission and reception procedure of the data suspended in BWP l. For example, a retransmission procedure of data at BWP l may be performed.

16 is a conceptual diagram illustrating a first embodiment of an uplink communication procedure according to a BWP change method 3 in an FDD communication system.

Referring to FIG. 16, BWP i and j may be UL BWP, and BWP 1 may be DL BWP. Each of BWP i, j, and l may be a different BWP. T _{UL, 5} , T _{UL, 6} , T _{UL, 7} , T _{UL, 8} , T _{UL, 9} , T _{UL, 10} , T _{UL, 11} , T _{UL, 12} , and T _{UL, 13} are shown in FIG. 6, respectively. It can correspond to the illustrated T _{UL, 5} , T _{UL, 6} , T _{UL, 7} , T _{UL, 8} , T _{UL, 9} , T _{UL, 10} , T _{UL, 11} , T _{UL, 12} , and T _{UL, 13} have. The base station and the terminal may perform uplink communication in BWP i. If a change from BWP i to BWP j is required, the base station may transmit BWP change information indicating a change in BWP (for example, from BWP i to BWP j) at least one of an RRC message, a MAC CE, and a downlink control channel. The above transmission is possible. The BWP change information may include one or more of a BWP change indicator, a BWP change time point, and information indicating a new BWP (eg, BWP ID, BWP index, bitmap, BWP change pattern).

The UE may receive BWP change information from the base station by monitoring the downlink control channel, and may confirm that a change from BWP i to BWP j is requested based on the BWP change information. In addition, the terminal may check the BWP change time point based on the BWP change information. When the BWP change information is received, the terminal may transmit a response (for example, ACK or NACK) to the base station for the BWP change information. When an acknowledgment (ACK) for the BWP change information is received from the terminal, the base station may determine that the BWP change information has been successfully received at the terminal. If the base station does not receive an acknowledgment (ACK) for the BWP change information from the terminal, receives a negative response (NACK), or does not receive a response within a predefined time, the base station is the BWP change information It may be regarded as not received at the terminal. In this case, the base station may request BWP change by retransmitting BWP change information or transmitting new BWP change information to the UE. On the other hand, when a plurality of BWP change information is received, the terminal may change the BWP based on the information indicated by the most recent BWP change information.

The base station and the terminal may change the operation BWP at a time point set by the base station or a preset time point. For example, when the operation BWP is changed from BWP i to BWP j, the base station and the terminal may suspend (eg, suspend) the uplink communication procedure from the transmission and reception time of the BWP change information to the BWP change time, and the BWP After i is changed to BWP j, a new uplink communication procedure may be performed in BWP j.

Even when the procedure for transmitting / receiving data in the BWP i is not completed, the base station and the terminal may change the operation BWP from BWP i to BWP j. For example, when data that is not transmitted to the base station in the BWP i exists in the terminal (for example, when a NACK for uplink data is received from the base station, the terminal of the resource allocation information for retransmission of the uplink data In case of expecting reception, or when retransmission of the HARQ response is required for downlink data, the UE suspends the corresponding uplink communication procedure (for example, retransmission of uplink data and retransmission of HARQ response). , BWP can be changed from BWP i to BWP j.

In this case, the base station may expect that the uplink communication procedure held in BWP i is resumed after the procedure for transmitting and receiving new data in BWP j is completed. Therefore, the base station discards the data stored in the soft buffer (eg, soft bits, LLR) and information for receiving the data and reallocating uplink data to the corresponding UE (eg, HARQ process ID, RV, NDI). I can keep it without doing it. The terminal may maintain data (eg, soft bits) stored in the soft buffer for transmission and information (eg, HARQ process ID, RV, NDI) for transmission of the corresponding data without discarding.

If the procedure for sending or receiving data in BWP i is not completed, and the procedure for sending and receiving data in BWP j is completed after changing from BWP i to BWP j, the base station changes the BWP (for example, from BWP j to BWP i). The indicating BWP change information may be transmitted through at least one of an RRC message, a MAC CE, and a downlink control channel. The BWP change information may include one or more of a BWP change indicator, a BWP change time point, and information indicating a new BWP (eg, BWP ID, BWP index, bitmap, BWP change pattern).

The UE may receive the BWP change information from the base station by monitoring the downlink control channel, and may confirm that a change from BWP j to BWP i is requested based on the BWP change information. In addition, the terminal may check the BWP change time point based on the BWP change information. When the BWP change information is received, the terminal may transmit a response (for example, ACK or NACK) to the base station for the BWP change information. When an acknowledgment (ACK) for the BWP change information is received from the terminal, the base station may determine that the BWP change information has been successfully received at the terminal. If the base station does not receive an acknowledgment (ACK) for the BWP change information from the terminal, receives a negative response (NACK), or does not receive a response within a predefined time, the base station is the BWP change information It may be regarded as not received at the terminal. In this case, the base station may request BWP change by retransmitting BWP change information or transmitting new BWP change information to the UE. On the other hand, when a plurality of BWP change information is received, the terminal may change the BWP based on the information indicated by the most recent BWP change information.

The base station and the terminal may change the operation BWP from BWP j to BWP i at the time of BWP change, and resume the transmission and reception procedure of the data suspended in the BWP i. For example, a retransmission procedure of data may be performed at BWP i.

Or, if the data transmission / reception procedure is not completed in BWP i, and the data transmission / reception procedure is completed in BWP j after changing from BWP i to BWP j, the base station and the terminal operate the BWP without signaling the BWP change information. You can change it to i. For example, the base station and the terminal may change the operation BWP from BWP j to BWP i after a preset duration from the completion of the data transmission / reception procedure in BWP j, and resume the transmission / reception procedure of the data held in BWP i. have. Here, the preset duration may be set by at least one of an RRC message, a MAC CE, and a downlink control channel.

17A is a conceptual diagram illustrating a first embodiment of a downlink communication procedure according to a BWP change method 3 in a TDD communication system, and FIG. 17B is a first embodiment of an uplink communication procedure according to a BWP change method 3 in a TDD communication system. A conceptual diagram showing the.

17A and 17B, the subframe may be an SC subframe. The frame (eg, subframe) structure may be determined according to downlink control / data channel transmission, downlink data configuration, and uplink data configuration. Each of BWP i and j may be a different BWP.

The downlink communication procedure illustrated in FIG. 17A may be performed the same as or similar to the downlink communication procedure illustrated in FIG. 15A. The base station and the terminal may change the operation BWP at a time point set by the base station or a preset time point. For example, when the operation BWP is changed from BWP i to BWP j, even if the data transmission and reception procedure is not completed in BWP i, the base station and the terminal may change the operation BWP from BWP i to BWP j, and BWP j In the new data transmission / reception procedure may be performed.

In this case, the terminal may expect that the downlink communication procedure held in the BWP i will resume after the transmission and reception procedure of the new data in the BWP j is completed. Accordingly, the terminal may maintain the data stored in the soft buffer (eg, soft bit, LLR) and information for resuming transmission and reception of the data (eg, HARQ process ID, RV, NDI) without discarding it. When the data transmission / reception procedure is completed in BWP j, the base station and the terminal may change the operation BWP from BWP j to BWP i, and may resume the transmission / reception procedure of the data held in BWP i. Here, T _{DL, 3} , T _{DL, 4} , T _{DL, 5} , T _{DL, 6} , T _{DL, 7} , T _{DL, 8} , T _{DL, 9} , T _{DL, 10} , and T _{DL, 11} respectively T _{DL, 3} , T _{DL, 4} , T _{DL, 5} , T _{DL, 6} , T _{DL, 7} , T _{DL, 8} , T _{DL, 9} , T _{DL, 10} , and T _{DL, 11 shown} in 5 It can respond.

The uplink communication procedure illustrated in FIG. 17B may be performed the same as or similar to the uplink communication procedure illustrated in FIG. 16. The base station and the terminal may change the operation BWP at a time point set by the base station or a preset time point. For example, when the operation BWP is changed from BWP i to BWP j, even if the data transmission and reception procedure is not completed in BWP i, the base station and the terminal may change the operation BWP from BWP i to BWP j, and BWP j In the new data transmission / reception procedure may be performed.

In this case, the base station may expect that the uplink communication procedure held in BWP i is resumed after the procedure for transmitting and receiving new data in BWP j is completed. Accordingly, the base station can maintain the data stored in the soft buffer (eg, soft bit, LLR) and information for resuming data transmission and reception (eg, HARQ process ID, RV, NDI) without discarding it. When the data transmission / reception procedure is completed in BWP j, the base station and the terminal may change the operation BWP from BWP j to BWP i, and may resume the transmission / reception procedure of the data held in BWP i. Here, T _{UL, 5} , T _{UL, 6} , T _{UL, 7} , T _{UL, 8} , T _{UL, 9} , T _{UL, 10} , T _{UL, 11} , T _{UL, 12} , and T _{UL, 13} are shown in FIG. T _{UL, 5} , T _{UL, 6} , T _{UL, 7} , T _{UL, 8} , T _{UL, 9} , T _{UL, 10} , T _{UL, 11} , T _{UL, 12} , and T _{UL, 13 shown} in 6 It can respond.

On the other hand, according to the BWP change method 3 described above, the reliability of the communication system may not be degraded. However, since the data retransmission procedure held at a specific BWP is resumed when the operation BWP of the communication node is changed back to the previous operation BWP (for example, when it comes back), a data transmission delay may occur and unnecessary data buffering may occur. Operation can degrade the performance of the communication system.

If the change cycle of the BWP is short in the communication system, the BWP change method 3 can be usefully used. The BWP change period may be preset between the base station and the terminal, and the base station and the terminal may change the operation BWP to a new BWP according to the BWP change period.

18 is a conceptual diagram illustrating a first embodiment of a data (re) transmission procedure according to the BWP change method 3 in the communication system.

Referring to FIG. 18, the BWP to which retransmission data is transmitted may be the same as the BWP to which original data is transmitted. For example, when data having HARQ process 1 is first transmitted in BWP 1, a retransmission procedure of data having HARQ process 1 is performed by a change procedure of “BWP 1 → BWP 2 → BWP 3 → BWP 2 → BWP 1”. And then performed at BWP 1. When data having HARQ process 2 is first transmitted in BWP 2, a retransmission procedure of data having HARQ process 2 may be performed in BWP 2 after a change procedure of “BWP 2 → BWP 3 → BWP 2” is performed. When the data having HARQ process 3 is first transmitted in BWP 3, the retransmission procedure of the data having HARQ process 3 is performed after the change procedure of “BWP 3 → BWP 2 → BWP 1 → BWP 2 → BWP 3” is performed. It can be performed in.

If the data retransmission procedure is performed in the same BWP, retransmission delay of data may occur due to the BWP change. To solve this problem, data retransmission procedures may be allowed to be performed at different BWPs. For example, if there are common frequency resources in BWP 1 and BWP 3, a retransmission procedure for data transmitted in BWP 1 (eg, initial data) may be performed in BWP 3 and transmitted in BWP 3. The retransmission procedure for data (eg, initial data) may be performed at BWP 1. In this case, the retransmission delay of data can be reduced.

19 is a conceptual diagram illustrating a second embodiment of a data (re) transmission procedure according to the BWP change method 3 in the communication system.

Referring to FIG. 19, if there are overlapping frequency resources (eg, common frequency resources) between BWP 1 and BWP 3, a retransmission procedure for data transmitted in BWP 1 may be performed in BWP 3. For example, the retransmission procedure for data transmitted in BWP 3 may be performed in BWP 1.

To this end, the base station may select either "information indicating that a retransmission procedure for data transmitted in BWP 1 is performed in BWP 3 (for example, information indicating resources allocated for data retransmission in BWP 3)" or "BWP." Information indicating that a retransmission procedure for data transmitted in 3 is performed in BWP 1 (for example, information indicating resources allocated for data retransmission in BWP 1), " RRC message, MAC CE, and downlink " It may be transmitted to the terminal through at least one of the control channels. The terminal may perform a data retransmission procedure in different BWPs based on the information received from the base station.

The UE may decode the DCI according to a control channel element (CCE) aggregation level by performing blind decoding on the downlink control channel. When a plurality of BWPs are used in the communication system, different control channel regions may be set in different BWPs. For example, a control resource set (CORESET) set in BWP 1 may be different from a CORESET set in BWP 3. If the data retransmission procedure is allowed to be performed in different BWPs (eg, BWP 1 and BWP 3), the UE may perform information (eg, resource allocation information) or uplink data for retransmission of downlink data. A downlink control channel may be received to receive information (eg, resource allocation information) for retransmission.

In this case, the base station uses the common frequency resources between the BWP 1 and BWP 3 information for retransmission of downlink data (for example, resource allocation information) or information for retransmission of uplink data (for example, resource allocation). Information), which can include a downlink control channel. Accordingly, the base station may configure the terminal to perform blind decoding on common frequency resources between BWP 1 and BWP 3. For example, the base station may preset a resource region (for example, common frequency resources between BWP 1 and BWP 3) on which blind decoding is performed, and may provide information indicating the set resource region to the RRC message, MAC CE, and the like. At least one of the downlink control channels may be transmitted to the terminal.

In addition, a separate CCE aggregation level may be set for the embodiment illustrated in FIG. 19 (eg, an embodiment in which a data retransmission procedure is performed in different BWPs). The CCE aggregation level for the embodiment shown in FIG. 19 is the CCE aggregation level for the embodiment shown in FIG. 18, the CCE aggregation level for the embodiment according to the BWP change method 1, and the embodiment according to the BWP change method 2. Can be set differently from the CCE aggregation level. The base station may transmit the CCE aggregation level for the embodiment illustrated in FIG. 19 to the terminal using at least one of an RRC message, a MAC CE, and a downlink control channel. The terminal may perform blind decoding on common resources between BWPs using the CCE aggregation level set by the base station.

Meanwhile, an uplink control channel (eg, an uplink control channel through which HARQ response and / or channel state information is transmitted) may exist in a BWP used for uplink data transmission. In this case, the uplink data channel set in the two BWPs may be configured / operated as an uplink control channel. Alternatively, a specific region in the BWP may be set / managed as an uplink control channel regardless of the BWP configuration. Alternatively, the terminal may transmit uplink control information together with uplink data through the uplink data channel.

3.1.4 How to Change BWP 4

Not only when the transmission and reception of data is completed at the time of BWP change but also when the transmission and reception of data are not completed, the communication node (for example, the base station and the terminal) may select an operation BWP (for example, BWP l) and a new BWP (eg, For example, it can be changed to BWP k). When transmission and reception of data is completed in BWP l, the communication node may perform a procedure of transmitting and receiving new data in BWP k. On the other hand, if the transmission and reception of data in BWP l is not completed, the communication node may perform the procedure of transmitting and receiving data in the previous operation BWP (ie, BWP l) continuously in the new (current) operation BWP (ie, BWP k). have.

20A and 20B are conceptual views illustrating a first embodiment of a downlink communication procedure according to a BWP change method 4 in an FDD communication system.

20A and 20B, BWP i may be an UL BWP, and BWP k and l may be DL BWP. Each of BWP i, k, and l may be a different BWP. On the time axis, the last slots shown in FIG. 20A may be contiguous with the start slots shown in FIG. 20B. That is, resource allocation information for retransmission according to FB (for example, NACK) indicated by ① in FIG. 20A may be transmitted through a control channel CTRL indicated by ① in FIG. 20B. T _{DL, 3} , T _{DL, 4} , T _{DL, 5} , T _{DL, 6} , T _{DL, 7} , T _{DL, 8} , T _{DL, 9} , T _{DL, 10} , and T _{DL, 11} are each shown in FIG. 5. It can correspond to the illustrated T _{DL, 3} , T _{DL, 4} , T _{DL, 5} , T _{DL, 6} , T _{DL, 7} , T _{DL, 8} , T _{DL, 9} , T _{DL, 10} , and T _{DL, 11} have. The base station and the terminal may perform downlink communication in BWP l. If a change from BWP l to BWP k is required, the base station may transmit BWP change information indicating a change in BWP (for example, from BWP l to BWP k) at least one of an RRC message, a MAC CE, and a downlink control channel. The above transmission is possible. For example, BWP change information may be included in DCI format 1_1.

The BWP change information may include one or more of a BWP change indicator, a BWP change time point, and information indicating a new BWP (eg, BWP ID, BWP index, bitmap, BWP change pattern). In addition, the BWP change information may further include resource allocation information for data (re) transmission in the new BWP.

The UE may receive BWP change information from the base station by monitoring the downlink control channel, and may confirm that a change from BWP 1 to BWP k is requested based on the BWP change information. In addition, the terminal may check resource allocation information at the BWP change time point and BWP k based on the BWP change information. When the BWP change information is received, the terminal may transmit a response (for example, ACK or NACK) to the base station for the BWP change information. When an acknowledgment (ACK) for the BWP change information is received from the terminal, the base station may determine that the BWP change information has been successfully received at the terminal. If the base station does not receive an acknowledgment (ACK) for the BWP change information from the terminal, receives a negative response (NACK), or does not receive a response within a predefined time, the base station is the BWP change information It may be regarded as not received at the terminal. In this case, the base station may request BWP change by retransmitting BWP change information or transmitting new BWP change information to the UE. On the other hand, when a plurality of BWP change information is received, the terminal may change the BWP based on the information indicated by the most recent BWP change information.

The base station and the terminal may change the operation BWP at a time point set by the base station or a preset time point. For example, when the operation BWP is changed from BWP l to BWP k, when the data transmission / reception procedure is completed in BWP l at the time of BWP change, the base station and the terminal may perform a new data transmission / reception procedure at BWP k. On the other hand, when the procedure for transmitting and receiving data at BWP l is not completed at the time of BWP change, the base station and the UE transmit a data transmission / reception procedure at the previous operation BWP (eg, BWP l) to a new (current) operation BWP (for example, , BWP k) may be performed continuously, and when the data transmission / reception procedure is completed, new data transmission / reception procedure may be performed in BWP k.

In this case, the UE may expect that the procedure of transmitting and receiving data in the previous operation BWP (eg, BWP 1) is continuously performed in the new (current) operation BWP (eg, BWP k). Accordingly, the terminal may store data (for example, data received in a BWPl data transmission / reception procedure) of the soft buffer after the BWP change point and information for continuously transmitting and receiving the data (for example, HARQ process ID). , RV, NDI) can be maintained without discarding. Here, the procedure of transmitting / receiving data in the previous operation BWP (eg, BWP l) may include resources indicated by BWP change information or resources set by the base station in the new (current) operation BWP (eg, BWP k). Can be performed using the

21 is a conceptual diagram illustrating a first embodiment of an uplink communication procedure according to a BWP change method 4 in an FDD communication system.

Referring to FIG. 21, BWP i and j may be UL BWP, and BWP 1 may be DL BWP. Each of BWP i, j, and l may be a different BWP. T _{UL, 5} , T _{UL, 6} , T _{UL, 7} , T _{UL, 8} , T _{UL, 9} , T _{UL, 10} , T _{UL, 11} , T _{UL, 12} , and T _{UL, 13} are shown in FIG. 6, respectively. It can correspond to the illustrated T _{UL, 5} , T _{UL, 6} , T _{UL, 7} , T _{UL, 8} , T _{UL, 9} , T _{UL, 10} , T _{UL, 11} , T _{UL, 12} , and T _{UL, 13} have. The base station and the terminal may perform uplink communication in BWP i. If a change from BWP i to BWP j is required, the base station may transmit BWP change information indicating a change in BWP (for example, from BWP i to BWP j) at least one of an RRC message, a MAC CE, and a downlink control channel. The above transmission is possible.

The BWP change information may include one or more of a BWP change indicator, a BWP change time point, and information indicating a new BWP (eg, BWP ID, BWP index, bitmap, BWP change pattern). In addition, the BWP change information may further include resource allocation information (eg, resource allocation information for HARQ response) for data (re) transmission in the new BWP. For example, BWP change information may be included in DCI format 1_1.

The UE may receive BWP change information from the base station by monitoring the downlink control channel, and may confirm that a change from BWP i to BWP j is requested based on the BWP change information. In addition, the UE may check resource allocation information at the time of BWP change and the new BWP based on the BWP change information. When the BWP change information is received, the terminal may transmit a response (for example, ACK or NACK) to the base station for the BWP change information. When an acknowledgment (ACK) for the BWP change information is received from the terminal, the base station may determine that the BWP change information has been successfully received at the terminal. If the base station does not receive an acknowledgment (ACK) for the BWP change information from the terminal, receives a negative response (NACK), or does not receive a response within a predefined time, the base station is the BWP change information It may be regarded as not received at the terminal. In this case, the base station may request BWP change by retransmitting BWP change information or transmitting new BWP change information to the UE. On the other hand, when a plurality of BWP change information is received, the terminal may change the BWP based on the information indicated by the most recent BWP change information.

The base station and the terminal may change the operation BWP at a time point set by the base station or a time point set in advance. For example, when the operation BWP is changed from BWP i to BWP j, when the data transmission / reception procedure of the BWP i is completed at the time of BWP change, the base station and the UE may perform the transmission / reception procedure of new data in BWP j. . On the other hand, if the data transmission and reception procedure in the BWP i is not completed at the time of the BWP change, the base station and the terminal is a new (current) operation BWP (for example, in the previous operation BWP (for example, BWP i) For example, BWP j) may be continuously performed, and when the data transmission / reception procedure is completed, new data transmission / reception procedure may be performed in BWP j.

In this case, the base station may expect that the procedure for transmitting and receiving data in the previous operation BWP (eg, BWP i) is performed continuously in the new (current) operation BWP (eg, BWP j). Therefore, the base station can maintain the data stored in the soft buffer after the BWP change time (for example, the data received in the procedure of transmitting / receiving the data of the BWP i). In addition, the base station does not discard information (eg, HARQ process ID, RV, NDI) for continuously performing resource allocation procedure and data retransmission procedure (eg, retransmission data transmission procedure) for the corresponding data retransmission. I can keep it without. In addition, the UE may maintain the data stored in the soft buffer for retransmission of the corresponding data and information for retransmission (for example, HARQ process ID, RV, NDI) in order to continuously perform the data transmission / reception procedure. Here, the procedure of transmitting and receiving data in the previous operation BWP (eg, BWP i) is performed in the new operation BWP (eg, BWP j) using resources indicated by the BWP change information or resources set by the base station. Can be.

FIG. 22 is a conceptual diagram illustrating a first embodiment of a downlink and uplink communication procedure according to a BWP change method 4 in a TDD communication system.

Referring to FIG. 22, a subframe may be an SC subframe. The frame (eg, subframe) structure may be determined according to downlink control / data channel transmission, downlink data configuration, and uplink data configuration. Each of BWP i and j may be a different BWP.

The downlink communication procedure illustrated in FIG. 22 may be performed the same as or similar to the downlink communication procedure illustrated in FIG. 20A. The base station and the terminal may change the operation BWP at a time point set by the base station or a preset time point. For example, when the operation BWP is changed from BWP i to BWP j, when the data transmission / reception procedure of the BWP i is completed at the time of BWP change, the base station and the UE may perform the transmission / reception procedure of new data in BWP j. . On the other hand, if the data transmission and reception procedure in the BWP i is not completed at the time of the BWP change, the base station and the terminal is a new (current) operation BWP (for example, in the previous operation BWP (for example, BWP i) For example, BWP j) may be continuously performed, and when the data transmission / reception procedure is completed, new data transmission / reception procedure may be performed in BWP j. Here, T _{DL, 3} , T _{DL, 4} , T _{DL, 5} , T _{DL, 6} , T _{DL, 7} , T _{DL, 8} , T _{DL, 9} , T _{DL, 10} , and T _{DL, 11} respectively T _{DL, 3} , T _{DL, 4} , T _{DL, 5} , T _{DL, 6} , T _{DL, 7} , T _{DL, 8} , T _{DL, 9} , T _{DL, 10} , and T _{DL, 11 shown} in 5 It can respond.

The uplink communication procedure shown in FIG. 22 may be performed the same as or similar to the uplink communication procedure shown in FIG. 21. The base station and the terminal may change the operation BWP at a time point set by the base station or a preset time point. For example, when the operation BWP is changed from BWP j to BWP i, when the transmission and reception of data in BWP j is completed at the time of BWP change, the base station and the terminal may perform a transmission and reception procedure of new data in BWP i. . On the other hand, when the procedure for transmitting and receiving data in BWP j is not completed at the time of BWP change, the base station and the terminal change the procedure for transmitting and receiving data in the previous operation BWP (eg, BWP j). For example, the BWP i) may be continuously performed, and when the data transmission / reception procedure is completed, the BWP i may perform the new data transmission / reception procedure.

Meanwhile, the data transmission delay according to the BWP change method 4 described above may be the same as the data transmission delay in the embodiment in which the BWP is not changed.

1.2 BWP  How to Order Changes

1.2.1 By Downlink Control Channel BWP  How to change

The BWP change information may be transmitted from the base station to the terminal using at least one of an RRC message, a MAC CE, and a downlink control channel. The BWP change information includes the BWP change indicator, when to change the BWP, information indicating a new BWP (for example, BWP ID, BWP index, bitmap, BWP change pattern), and resource allocation for data (re) transmission at the new BWP. It can include one or more of the information.

The terminal may receive the BWP change information from the base station, and may perform the BWP change operation based on information elements included in the BWP change information. For example, the UE may perform the BWP change operation at the BWP change time point indicated by the BWP change information. Alternatively, the terminal may perform the BWP change operation immediately after receiving the BWP change information. Or, if the BWP change information includes the BWP change pattern, the UE may perform the BWP change operation according to the BWP change pattern.

After changing the operation BWP to a new BWP, the base station and the terminal may transmit and receive data using the resources indicated by the resource allocation information included in the BWP change information. Alternatively, the base station and the terminal may transmit and receive data using the resources allocated in the previous operation BWP after changing the operation BWP to a new BWP. When the downlink control channel including the BWP change information is received, the UE may transmit a HARQ response (eg, ACK or NACK) to the base station for the BWP change information. The base station may receive a HARQ response from the terminal, and may determine whether the BWP change information was successfully received at the terminal based on the HARQ response. When an acknowledgment (ACK) for the BWP change information is received from the terminal, the base station may determine that the BWP change information has been successfully received at the terminal. If the base station does not receive an acknowledgment (ACK) for the BWP change information from the terminal, receives a negative response (NACK), or does not receive a response within a predefined time, the base station is the BWP change information It may be regarded as not received at the terminal. In this case, the base station may request BWP change by retransmitting BWP change information or transmitting new BWP change information to the UE. On the other hand, when a plurality of BWP change information is received, the terminal may change the BWP based on the information indicated by the most recent BWP change information.

1.2.2 timer based BWP  How to change

A timer for changing the BWP may be set, and the communication node (eg, the base station and the terminal) may change the operation BWP to a new BWP when the timer expires. The BWP change method based on a timer may be performed as follows.

Step 0: Initial setup and basic conditions

* The base station may transmit a message including an inactive timer value (for example, a message including an RRC message or MAC CE) to the terminal. Inactive timer value can be set before changing BWP.

* The terminal sets the inactive timer value and the internal timer value of the terminal to the initial value (for example, 0) set by the base station.

* The terminal may receive a downlink control channel from the base station.

Step 1: The terminal can receive the downlink control channel in the current BWP.

Step 1-1: If a DCI including BWP change information is not received, the UE may increase an internal timer value.

Step 1-2: When a DCI including BWP change information is received, the UE may maintain or initialize the internal timer value.

Step 2: The terminal can check whether the internal timer has expired.

* Step 2-1: when the internal timer value increased in step 1-1 is equal to the inactive timer value (for example, when the internal timer expires), the terminal transfers the operation BWP to the previous BWP or the default (or dedicated) Can change to BWP.

* Step 2-2: If the internal timer value increased in step 1-1 is different from the inactive timer value (for example, the internal timer is valid), the terminal can perform again from step 1.

According to the BWP change method based on the above-described timer, the UE may check whether the BWP change information is included in the downlink control channel by receiving the downlink control channel each time. That is, since the terminal always receives the downlink control channel, the load of the terminal may increase. To solve this problem, the terminal may set the frame number (eg, the previous frame number or the new frame number) as the inactive timer value at the time of change of the frame (eg, the frame number). The UE may change the operation BWP to the previous BWP or the basic BWP when the current frame number is the same as the inactive timer value. Alternatively, if the current frame number is different from the inactive timer value, the terminal may perform the process again from step 1.

1.3 BWP  Operation method

In a specific BWP, sidelink communication may be performed instead of downlink / uplink communication, in which case the transmission delay of data in the communication system may be reduced. BWP, frame structure, and related parameters (eg, subcarrier spacing, bandwidth, number of resource blocks) for sidelink communication may be set. The configuration information for the sidelink communication may be applied to the connection / termination procedure of the sidelink communication and the BWP change procedure in the sidelink communication after the BWP change.

The BWP change information may include configuration information for sidelink communication (eg, BWP for sidelink communication, frame structure, and related parameters). Configuration information for sidelink communication may be transmitted using one or more of an RRC message, a MAC CE, and a downlink control channel.

The BWP configured in the unlicensed band may be divided into one or more sub BWPs, and the terminal may perform a clear channel assessment (CCA) operation in each of the one or more sub BWPs. The terminal may determine a sub BWP capable of data transmission based on the result of the CCA operation, change the operation BWP to the determined sub BWP, and perform a data transmission / reception procedure in the changed sub BWP. The BWP change information may include configuration information for the CCA (eg, BWP on which CCA is performed, a data structure, and related parameters (eg, subcarrier interval, bandwidth, RB number)). The configuration information for the CCA may be transmitted using one or more of an RRC message, a MAC CE, and a downlink control channel.

Meanwhile, in a communication system, a base station may transmit a synchronization block / physical broadcast channel (SS / PBCH) block through a specific BWP. The UE may receive an SS / PBCH block at a specific BWP, and may acquire synchronization information and system information based on the SS / PBCH block. Here, the SS / PBCH block may be transmitted and received as follows.

23A is a conceptual diagram illustrating a first embodiment of a method of transmitting / receiving an SS / PBCH block in a communication system.

Referring to FIG. 23A, UE 1 may perform a connection establishment procedure with a base station in an initial BWP, and dedicated BWPs 1 and 2 for UE 1 may be set when a connection establishment procedure between UE 1 and a base station is completed. UE 1 may receive SS / PBCH block 1 from the base station in the first BWP.

The terminal 2 may perform a connection establishment procedure with the base station in the first BWP, and when the connection establishment procedure between the terminal 2 and the base station is completed, dedicated BWPs 1 and 2 for the terminal 2 may be set. The frequency band of the first BWP of the terminal 2 may be the same as the frequency band of the first BWP of the terminal 1. Terminal 2 may receive the SS / PBCH block 1 from the base station in the first BWP.

UE 3 may perform a connection establishment procedure with the base station in the first BWP, and when the connection establishment procedure between UE 3 and the base station is completed, dedicated BWPs 1 and 2 for UE 3 may be set. The frequency band of the first BWP of the terminal 3 may be different from the frequency band of the first BWP of the terminal 1 and the frequency band of the first BWP of the terminal 2. UE 3 may receive SS / PBCH block 3 from the base station in the first BWP.

When the initial BWPs of the terminals are different from each other, the base station may repeatedly transmit an SS / PBCH block including similar information through different BWPs. To solve this problem, the SS / PBCH block may be transmitted and received as follows.

23B is a conceptual diagram illustrating a second embodiment of a method of transmitting / receiving an SS / PBCH block in a communication system.

Referring to FIG. 23B, when the frequency band of the first BWP of the terminal 3 is different from the frequency band of the first BWP of the terminal 1 and the frequency band of the first BWP of the terminal 2, the base station receives the BWP change information indicating the change of the initial BWP. Can send to 3. The BWP change information may indicate to change the first BWP of the terminal 3 to the first BWP of the terminal 1 or the terminal 2. The terminal 3 may receive BWP change information from the base station, and may change the first BWP of the terminal 3 to the first BWP of the terminal 1 or the terminal 2 based on the BWP change information.

When the first BWP of UE 3 is changed, the base station may transmit SS / PBCH block 1 to UEs 1-3 through the same frequency band (eg, the first BWP), and UE 1-3 may transmit the same frequency band (eg For example, the first BWP) may receive the SS / PBCH block 1 from the base station.

On the other hand, when a plurality of BWPs are used in a communication system supporting sidelink communication or unlicensed band communication (eg, licensed-assistance access (LAA) communication, NR-based access to unlicensed spectrum (NR-U) communication) In a new BWP change procedure, a new BWP may be indicated as follows.

24 is a conceptual diagram illustrating a first embodiment of a bitmap indicating a new BWP in a communication system.

Referring to FIG. 24, in the BWP change procedure, the base station may transmit BWP change information including a bitmap indicating a new BWP to the terminal. The size of the bitmap may be 1 octet or more, and each of the bits included in the bitmap may match one BWP. For example, if eight BWPs are used in a communication system, each of D ₀ , D ₁ , D ₂ , D ₃ , D ₄ , D ₅ , D ₆ , and D ₇ may be BWP 1, BWP 2, BWP 3, May be mapped to BWP 4, BWP 5, BWP 6, and BWP 7. A bit set to "0" in the bitmap may indicate that the BWP mapped to the corresponding bit is deactivated, and a bit set to "1" in the bitmap may indicate that the BWP mapped to the corresponding bit is activated.

When the operation BWP of the terminal is required to be changed to BWP 4, the base station may set a bitmap as shown in Table 4 below, and may transmit BWP change information including the bitmap to the terminal.

The terminal may receive the BWP change information from the base station, and may confirm that D ₃ is set to "1" in the bitmap included in the BWP change information. In this case, the UE may change the operation BWP to BWP 4 indicated by the bitmap, and perform a data transmission / reception procedure in BWP 4. The BWP change time point may be a time point indicated by the BWP change information or a time point preset between the base station and the terminal. The BWP IDs may be sorted according to a preset rule (eg, ascending or descending order).

1.4 BWP transition point

1.4.1 When to switch BWPs in downlink communication procedure

FIG. 25 is a conceptual diagram illustrating a first embodiment of a BWP switching time point for downlink communication in a communication system.

Referring to FIG. 25, the base station may transmit "resource allocation information and BWP change information for downlink data" or "BWP change information" to the terminal through a downlink control channel (CTRL). The BWP change information may include a BWP change time point (eg, Alt 1, Alt 2, Alt 3, Alt 4). When the BWP change information is received, the terminal may transmit a response (for example, ACK or NACK) to the base station for the BWP change information. When an acknowledgment (ACK) for the BWP change information is received from the terminal, the base station may determine that the BWP change information has been successfully received at the terminal. An acknowledgment (ACK) for the BWP change information may be sent in the previous operation BWP (eg, BWP i) or the new operation BWP (eg, BWP j). If the base station does not receive an acknowledgment (ACK) for the BWP change information from the terminal, receives a negative response (NACK), or does not receive a response within a predefined time, the base station is the BWP change information It may be regarded as not received at the terminal. In this case, the base station may request BWP change by retransmitting BWP change information or transmitting new BWP change information to the UE. On the other hand, when a plurality of BWP change information is received, the terminal may change the BWP based on the information indicated by the most recent BWP change information.

Resource allocation information for HARQ response (eg, ACK or NACK) to the BWP change information may be transmitted through the downlink control channel together with the BWP change information. Or, if the resource allocation information and the BWP change information for the downlink data is transmitted through the downlink control channel, the HARQ response for the BWP change information may be replaced with a HARQ response for the downlink data. In this case, the HARQ response to the BWP change information may be omitted.

After the BWP change information is transmitted and received, the base station and the terminal may change the operation BWP from BWP i to BWP j in Alt 1, Alt 2, Alt 3, or Alt 4 below. Alt 1, Alt 2, Alt 3, or Alt 4 may be indicated by the BWP change information. Alternatively, Alt 1, Alt 2, Alt 3, or Alt 4 may be preconfigured between the base station and the terminal through an RRC signaling procedure, and the base station and the terminal are pre-configured Alt 1, Alt 2, Alt after transmitting and receiving BWP change information. You can change the behavior BWP from BWP i to BWP j at 3 or Alt 4.

Alt 1: The BWP may be changed to a new BWP at the boundary of the slot, subframe, or TTI (eg, starting point of the slot, subframe, or TTI). The base station provides information indicating that the BWP is to be changed at the boundary of the slot, subframe, or TTI (eg, starting point of the slot, subframe, or TTI) at least among the RRC message, the MAC CE, and the downlink control channel. One or more may be transmitted to the terminal. For example, when a downlink control channel including BWP change information is transmitted and received in slot #n, subframe #n, or TTI #n, the base station and the terminal are slot #n, subframe #n, or TTI #n. At the start of slot # n + 1, subframe # n + 1, or TTI # n + 1, the operation BWP may be changed from BWP i to BWP j.

Alternatively, the base station and the terminal may change the operation BWP (eg, BWP i) to a new BWP (eg, BWP j) before the time of transmission and reception of the downlink control channel including resource allocation information of uplink data. . In this case, the downlink control channel transmitted in the new BWP (eg, BWP j) may include resource allocation information for HARQ response for the downlink data transmitted in the previous operation BWP (eg, BWP i). Can be.

Alt 2: Radio frequency (RF) switching may be performed between downlink transmission and uplink transmission in a TDD communication system (or an unpaired spectrum). The BWP can be changed to a new BWP at the RF switching point. For example, the BWP may be changed to a new BWP at the start or end of a guard period (GP). The base station may transmit information indicating that the BWP is changed at the start point or end point of the GP to the terminal using at least one of an RRC message, a MAC CE, and a downlink control channel. The HARQ response to the downlink data in the previous operation BWP (eg, BWP i) may be transmitted in the new operation BWP (eg, BWP j). Resource allocation information for the HARQ response to the downlink data may be transmitted through the downlink control channel with the BWP change information.

Alt 3: BWP may be changed to a new BWP at the start of uplink transmission region (UL). For example, an HARQ response (FB) for downlink data is transmitted in a previous operation BWP (eg, BWP i), and an uplink transmission area (UL) is transmitted after an HARQ response (FB) for downlink data. If present, the base station and the terminal may change the operation BWP from BWP i to BWP j at the start of the uplink transmission region (UL).

The base station may transmit information indicating that the BWP is changed at the start of the uplink transmission region (UL) to the terminal using at least one of an RRC message, a MAC CE, and a downlink control channel. In addition, the resource allocation information for uplink data in the new operation BWP (eg, BWP j) may be transmitted through the downlink control channel in the previous operation BWP (eg, BWP i).

Alt 4: BWP may be changed to a new BWP at the boundary of a slot, subframe, or TTI (eg, starting point of the slot, subframe, or TTI). The base station provides information indicating that the BWP is to be changed at the boundary of the slot, subframe, or TTI (eg, starting point of the slot, subframe, or TTI) at least among the RRC message, the MAC CE, and the downlink control channel. One or more may be transmitted to the terminal. Here, the BWP may be changed after the slot, subframe, or TTI including the UL transmission region (UL).

For example, a downlink control channel including BWP change information is transmitted and received in slot #n, subframe #n, or TTI #n, and an uplink transmission region (UL) is slot # n + 1, subframe #n. If it belongs to +1 or TTI # n + 1, the base station and the UE change the operation BWP from BWP i to BWP j at the start of slot # n + 2, subframe # n + 2, or TTI # n + 2. Can be. The HARQ response for the uplink data transmitted in the previous operation BWP (eg, BWP i) may be transmitted in a new BWP (eg, BWP j).

1.4.2 BWP Transition Point in Uplink Communication Procedures

FIG. 26 is a conceptual diagram illustrating a first embodiment of a BWP switching time point for uplink communication in a communication system.

Referring to FIG. 26, the base station may transmit "resource allocation information and BWP change information for uplink data" or "BWP change information" to the terminal through a downlink control channel (CTRL). The BWP change information may include a BWP change time point (eg, Alt 1, Alt 2, Alt 3, Alt 4). When the BWP change information is received, the terminal may transmit a response (for example, ACK or NACK) to the base station for the BWP change information. When an acknowledgment (ACK) for the BWP change information is received from the terminal, the base station may determine that the BWP change information has been successfully received at the terminal. If the base station does not receive an acknowledgment (ACK) for the BWP change information from the terminal, receives a negative response (NACK), or does not receive a response within a predefined time, the base station is the BWP change information It may be regarded as not received at the terminal. In this case, the base station may request BWP change by retransmitting BWP change information or transmitting new BWP change information to the UE. On the other hand, when a plurality of BWP change information is received, the terminal may change the BWP based on the information indicated by the most recent BWP change information.

 The HARQ response to the BWP change information may be sent in a previous operation BWP (eg, BWP i) or a new operation BWP (eg, BWP j). Resource allocation information for HARQ response to the BWP change information may be transmitted through the downlink control channel together with the BWP change information. Alternatively, when resource allocation information and BWP change information for uplink data are transmitted through a downlink control channel, the HARQ response to the BWP change information may be replaced by transmission of uplink data. In this case, the HARQ response to the BWP change information may be omitted.

After the BWP change information is transmitted and received, the base station and the terminal may change the operation BWP from BWP i to BWP j in Alt 1, Alt 2, Alt 3, or Alt 4 below. Alt 1, Alt 2, Alt 3, or Alt 4 may be indicated by the BWP change information. Alternatively, Alt 1, Alt 2, Alt 3, or Alt 4 may be preconfigured between the base station and the terminal through an RRC signaling procedure, and the base station and the terminal are pre-configured Alt 1, Alt 2, Alt after transmitting and receiving BWP change information. You can change the behavior BWP from BWP i to BWP j at 3 or Alt 4.

Alt 1: RF switching may be performed between downlink transmission and uplink transmission in a TDD communication system (or unpaired spectrum). The BWP can be changed to a new BWP at the RF switching point. For example, the BWP may be changed to a new BWP at the start point or end point of the GP. The base station may transmit information indicating that the BWP is changed at the start point or end point of the GP to the terminal using at least one of an RRC message, a MAC CE, and a downlink control channel. In this case, the base station and the terminal may change the operation BWP from BWP i to BWP j at the start time or end time of the GP, and may perform an uplink communication procedure at BWP j. Resource allocation information for uplink data transmitted in BWP j may be transmitted through a downlink control channel in a previous operation BWP (eg, BWP i).

Alt 2: The BWP may be changed to a new BWP at the boundary of the slot, subframe, or TTI (eg, slot, subframe, or start time of the TTI). The base station provides information indicating that the BWP is to be changed at the boundary of the slot, subframe, or TTI (eg, slot, subframe, or starting point of the TTI) from among the RRC message, MAC CE, and downlink control channel. At least one or more may be transmitted to the terminal.

For example, a downlink control channel including resource allocation information and BWP change information for uplink data is transmitted and received in slot #n, subframe #n, or TTI #n, and uplink data is slot # n + 1. When the base station and the UE are transmitted and received using the resources indicated by the resource allocation information in the subframe # n + 1 or the TTI # n + 1, the base station and the terminal are slot # n + 1, the subframe # n + 1, or the TTI The operation BWP may be changed from BWP i to BWP j at the start of slot # n + 2 after # n + 1, subframe # n + 2, or TTI # n + 2. The base station and the terminal may perform an uplink communication procedure in BWP j.

Here, the base station may transmit resource allocation information for the HARQ response to the uplink data received at BWP i or the retransmission procedure of uplink data failed to be received at BWP i through a downlink control channel in BWP j. Or, the retransmission procedure of the uplink data failed to be received in BWP i may not be performed in BWP j.

Alt 3: If a downlink control channel including a HARQ response to uplink data or resource allocation information for retransmission of uplink data is transmitted in a previous operation BWP (eg, BWP i), the corresponding downlink control The channel may include resource allocation information for uplink data in a new operation BWP (eg, BWP j). Or, if a downlink control channel including resource allocation information for uplink data is transmitted in a new BWP (eg, BWP j), the corresponding downlink control channel is the previous operation BWP (eg, BWP i). May include resource allocation information for retransmission of uplink data that has failed transmission.

Alt 4: BWP may be changed to a new BWP at the boundary of a slot, subframe, or TTI (eg, starting point of the slot, subframe, or TTI). The base station provides information indicating that the BWP is to be changed at the boundary of the slot, subframe, or TTI (for example, at the beginning of the slot, subframe, or TTI), the RRC message, MAC CE, and downlink control channel. Can be transmitted to the terminal using at least one. Here, the BWP change may be changed at a slot, subframe, or slot, subframe, or TTI starting time point to which the UL transmission region (UL) belongs.

For example, a downlink control channel including BWP change information is transmitted and received in slot #n, subframe #n, or TTI #n, and an uplink transmission region (UL) is slot # n + 1, subframe #n. If it belongs to +1 or TTI # n + 1, the base station and the UE may change the BWP at the start of slot # n + 2, subframe # n + 2, or TTI # n + 2. Here, the base station may transmit resource allocation information for the HARQ response to the uplink data received at BWP i or the retransmission procedure of uplink data failed to be received at BWP i through a downlink control channel in BWP j.

1.5 How to Determine Candidate BWPs

For low latency and reliable data communication, communication nodes (eg, base stations and terminals) may perform measurement / reporting procedures of radio channel information for the BWP or candidate BWP to be switched. For example, the base station may manage the BWP to which the terminal performing communication in the current operating BWP can be switched. In addition, the base station may request the terminal to perform a measurement / report procedure of radio channel information for the candidate BWP as well as the current BWP used for communication between the base station and the terminal. For example, the base station may include a list of candidate BWPs, information indicating resources used for the measurement of radio channel status at the candidate BWP, and information indicating resources used for reporting the measurement result of radio channel status for the candidate BWP. Can be transmitted to the terminal.

When the execution of the measurement / reporting procedure of the radio channel information for the candidate BWP is requested, the terminal may measure the radio channel state in the candidate BWP and report the measurement result (ie, radio channel information) to the base station. The base station may receive a measurement result (ie, radio channel information) for the candidate BWP from the terminal, and switchable BWPs (eg, one or more candidates among candidate BWPs) based on the measurement result (ie, radio channel information). BWP) can be determined. The base station may inform the terminal of the switchable BWP. In addition, the base station may prepare in advance data allocation in the current operation BWP and the destination BWP (ie, switchable BWP) based on the measurement result (ie, radio channel information).

When the current BWP is switched to the candidate BWP determined by the base station, the communication node (eg, the base station and the terminal) may change the BWP based on the BWP change method 1-4 described above.

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

Examples of computer readable media include hardware devices that are specifically configured to store and execute program instructions, such as ROM, RAM, flash memory, and the like. Examples of program instructions include machine language code, such as produced by a compiler, as well as high-level language code that can be executed by a computer using an interpreter or the like. The hardware device described above may be configured to operate with at least one software module to perform the operations of the present invention, and vice versa.

Although described with reference to the embodiments above, those skilled in the art will understand that the present invention can be variously modified and changed without departing from the spirit and scope of the invention as set forth in the claims below. Could be.

Claims (20)

As an operation method of a terminal in a communication system,
Receiving BWP change information from a base station in bandwidth part (BWP) i;
Changing the operating BWP of the terminal from BWP i to BWP j even when the BWP change time indicated by the BWP change information is not completed, even when the procedure of transmitting and receiving the first data in the BWP i is not completed; ; And
Performing a transmission / reception procedure of second data in the BWP j,
The BWP i and the BWP j is a different BWP, i and j are different integers, the operation method of the terminal. The method according to claim 1,
The transmission and reception procedure of the first data is terminated at the BWP change time point, and a soft bit for the first data stored in a buffer of the terminal or the base station is deleted. The method according to claim 1,
The operation method of the terminal,
If the first data transmission and reception procedure is suspended at the BWP change time point, and the second data transmission and reception procedure is completed in the BWP j,
Changing the operation BWP from the BWP j to the BWP i; And
Resuming a transmission / reception procedure of the reserved first data at the BWP i. The method according to claim 1,
The BWP change information is received through at least one of a radio resource control (RRC) message, a medium access control (MAC) control element, and a downlink control channel. The method according to claim 1,
The BWP change information is received via a downlink control channel together with resource allocation information for the first data. The method according to claim 1,
The BWP change information includes a BWP change indicator indicating that a BWP change is requested, the BWP change time point, and information indicating a new BWP. The method according to claim 1,
The BWP change time point is one of a start time of a slot, a start time of a subframe, a start time of a transmission time interval (TTI), an end time of a guard period (GP), and a start time of an uplink transmission region. Way. The method according to claim 1,
The transmission and reception procedure of the first data and the transmission and reception procedure of the second data are each performed with the base station or another terminal. As an operation method of a terminal in a communication system,
Receiving first BWP change information from a base station in bandwidth part (BWP) i;
At the first BWP change time point indicated by the first BWP change information, if the procedure for transmitting / receiving data in the BWP i is not completed, the data of the data in the BWP i without changing the BWP even after the first BWP change time point. Performing a transmission / reception procedure; And
Changing the operating BWP of the terminal from BWP i to BWP j when the data transmission / reception procedure is completed in the BWP i;
The BWP i and the BWP j is a different BWP, i and j are different integers, the operation method of the terminal. The method according to claim 9,
The operation BWP is changed from the BWP i to the BWP j after a preset duration from the completion of the data transmission and reception procedure. The method according to claim 9,
The operation BWP is changed from the BWP i to the BWP j at a second BWP change time point indicated by the second BWP change information received from the base station. The method according to claim 9,
The first BWP change information is received via at least one of a radio resource control (RRC) message, a medium access control (MAC) control element (MAC), and a downlink control channel. The method according to claim 9,
The first BWP change information is received via a downlink control channel together with resource allocation information for the data. The method according to claim 9,
The first BWP change information includes a BWP change indicator indicating that a BWP change is requested, the first BWP change time point, and information indicating a new BWP. The method according to claim 9,
The first BWP change time point is one of a start time of a slot, a start time of a subframe, a start time of a transmission time interval (TTI), an end time of a guard period (GP), and a start time of an uplink transmission region. Method of operation. As an operation method of a terminal in a communication system,
Receiving BWP change information from a base station in bandwidth part (BWP) i;
Changing an operating BWP of the terminal from BWP i to BWP j even when the BWP change time indicated by the BWP change information is not completed, even when the procedure of transmitting and receiving the first data in the BWP i is not completed;
Performing a transmission / reception procedure of the first data in the BWP j; And
Performing transmission and reception of second data in the BWP j when the transmission and reception procedure of the first data is completed,
The BWP i and the BWP j is a different BWP, i and j are different integers, the operation method of the terminal. The method according to claim 16,
The BWP change information is received through at least one of a radio resource control (RRC) message, a medium access control (MAC) control element, and a downlink control channel. The method according to claim 16,
The BWP change information is received via a downlink control channel together with resource allocation information for the data. The method according to claim 16,
The BWP change information includes a BWP change indicator indicating that a BWP change is requested, the BWP change time point, and information indicating a new BWP. The method according to claim 16,
The BWP change time point is one of a start time of a slot, a start time of a subframe, a start time of a transmission time interval (TTI), an end time of a guard period (GP), and a start time of an uplink transmission region. Way.

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