KR20200009911A - Method and apparatus for transmitting and receiving control information in wireless communication system - Google Patents

Abstract

The present disclosure relates to a method and apparatus for transmitting and receiving control information in a wireless communication system. According to some embodiments of the present invention, a method for transmitting control information may comprise the steps of: setting a control region for at least one terminal in consideration of a downlink control channel element to be searched by the at least one terminal; and providing information on the set control region.

Description

Method and apparatus for transmitting and receiving control information in a wireless communication system {METHOD AND APPARATUS FOR TRANSMITTING AND RECEIVING CONTROL INFORMATION IN WIRELESS COMMUNICATION SYSTEM}

The present disclosure relates to a wireless communication system, and more particularly, to a method and apparatus for smoothly providing a service in a wireless communication system. More specifically, the present invention relates to a method and apparatus for transmitting and receiving control information in a wireless communication system.

In order to meet the increasing demand for wireless data traffic since the commercialization of 4G communication system, efforts are being made to develop an improved 5G communication system or a pre-5G communication system. For this reason, a 5G communication system or a pre-5G communication system is called a system after a 4G network (Beyond 4G Network) or a system after an LTE system (Post LTE). The 5G communication system defined by 3GPP is called New Radio (NR) system. In order to achieve high data rates, 5G communication systems are being considered for implementation in the ultra-high frequency (mmWave) band (eg, such as the 60 Gigabit (60 GHz) band). In 5G communication system, beamforming, massive array multiple input / output (Full-Dimensional MIMO), and full dimensional multiple input / output (FD-MIMO) are used in 5G communication system to increase path loss mitigation of radio waves and increase transmission distance of radio waves. Array antenna, analog beam-forming, and large scale antenna techniques have been discussed and applied to NR systems. In addition, in order to improve the network of the system, 5G communication systems have advanced small cells, advanced small cells, cloud radio access network (cloud RAN), ultra-dense network (ultra-dense network) , Device to Device communication (D2D), wireless backhaul, moving network, cooperative communication, Coordinated Multi-Points (CoMP), and interference cancellation And other technology developments are being made. In addition, in 5G systems, Hybrid FSK and QAM Modulation (FQAM) and sliding window superposition coding (SWSC), Advanced Coding Modulation (ACM), and FBMC (Filter Bank Multi Carrier) and NOMA are advanced access technologies. Non-orthogonal multiple access and sparse code multiple access have been developed.

Meanwhile, the Internet has evolved from a human-centered connection network in which humans generate and consume information, and an Internet of Things (IoT) network that exchanges and processes information between distributed components such as things. Internet of Everything (IoE) technology, in which big data processing technology through connection with cloud servers and the like, is combined with IoT technology, is also emerging. In order to implement the IoT, technical elements such as sensing technology, wired / wireless communication and network infrastructure, service interface technology, and security technology are required, and recently, a sensor network for connection between things, a machine to machine , M2M), Machine Type Communication (MTC), etc. are being studied. In an IoT environment, intelligent Internet technology (IT) services that provide new value in human life by collecting and analyzing data generated from connected objects may be provided. IoT is a field of smart home, smart building, smart city, smart car or connected car, smart grid, health care, smart home appliances, advanced medical services, etc. through convergence and complex of existing IT (iInformation Technology) technology and various industries. It can be applied to.

Accordingly, various attempts have been made to apply the 5G communication system to the IoT network. For example, 5G communication such as a sensor network, a machine to machine (M2M), a machine type communication (MTC), and the like are implemented by techniques such as beamforming, MIMO, and array antennas. The application of cloud radio access network (cloud RAN) as the big data processing technology described above may be an example of convergence of 5G technology and IoT technology.

As described above and various services can be provided according to the development of the mobile communication system, there is a demand for a method for effectively providing these services.

The disclosed embodiment provides an apparatus and method capable of effectively providing a service in a wireless communication system.

According to an embodiment, a method of transmitting control information may include: setting a control region for at least one terminal in consideration of a downlink control channel element to be searched by at least one terminal; And providing information on the set control area.

1 is a diagram illustrating a basic structure of a time-frequency domain of a next generation mobile communication system according to an embodiment.
2 is a diagram illustrating a frame, subframe, and slot structure of a next generation mobile communication system according to an embodiment.
FIG. 3 is a diagram for describing a bandwidth part (BWP) setting of a next generation mobile communication system according to an exemplary embodiment.
4 is a diagram illustrating a control region setting of a downlink control channel of a next generation mobile communication system according to an embodiment.
5 is a diagram illustrating a structure of a downlink control channel of a next generation mobile communication system according to an embodiment.
6 is a diagram for describing a method of determining a maximum number of PDCCH candidate groups in a next generation mobile communication system according to an embodiment.
7 is a diagram for describing a method of calculating the maximum number of PDCCH candidate groups according to an embodiment.
8 is a diagram for describing a method of calculating the maximum number of PDCCH candidate groups according to another embodiment.
9 is a diagram illustrating an operation of a terminal according to an embodiment.
FIG. 10 is a diagram for describing a method of calculating the maximum number of PDCCH candidate groups according to another embodiment. FIG.
11 is a block diagram illustrating an internal structure of a terminal according to an embodiment.
12 is a block diagram illustrating an internal structure of a base station according to an embodiment.

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

In describing the embodiments, descriptions of technical contents that are well known in the technical field to which the present disclosure belongs and are not directly related to the present disclosure will be omitted. This is to more clearly communicate without obscure the subject matter of the present disclosure by omitting unnecessary description.

For the same reason, in the accompanying drawings, some components are exaggerated, omitted or schematically illustrated. In addition, the size of each component does not reflect the actual size entirely. The same or corresponding elements in each drawing are given the same reference numerals.

Advantages and features of the present disclosure, and methods of accomplishing the same will become apparent with reference to the embodiments described below in detail in conjunction with the accompanying drawings. However, the present disclosure is not limited to the embodiments disclosed below, but may be implemented in various forms, and the present embodiments are merely provided to make the present disclosure complete, and those of ordinary skill in the art to which the present disclosure belongs. It is provided to fully inform the scope of the invention, and the present disclosure is defined only by the scope of the claims. Like reference numerals refer to like elements throughout.

At this time, it will be understood that each block of the flowchart illustrations and combinations of flowchart illustrations may be performed by computer program instructions. Since these computer program instructions may be mounted on a processor of a general purpose computer, special purpose computer, or other programmable data processing equipment, those instructions executed through the processor of the computer or other programmable data processing equipment may be described in the flowchart block (s). It will create means to perform the functions. These computer program instructions may be stored in a computer usable or computer readable memory that can be directed to a computer or other programmable data processing equipment to implement functionality in a particular manner, and thus the computer usable or computer readable memory. It is also possible for the instructions stored in to produce an article of manufacture containing instruction means for performing the functions described in the flowchart block (s). Computer program instructions may also be mounted on a computer or other programmable data processing equipment, such that a series of operating steps may be performed on the computer or other programmable data processing equipment to create a computer-implemented process to create a computer or other programmable data. Instructions for performing the processing equipment may also provide steps for performing the functions described in the flowchart block (s).

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

In this case, the term '~ part' used in the present embodiment refers to software or a hardware component such as an FPGA or an ASIC, and '~ part' performs certain roles. However, '~' is not meant to be limited to software or hardware. '~ Portion' may be configured to be in an addressable storage medium or may be configured to play one or more processors. Thus, as an example, '~' means components such as software components, object-oriented software components, class components, and task components, and processes, functions, properties, procedures, and the like. Subroutines, segments of program code, drivers, firmware, microcode, circuits, data, databases, data structures, tables, arrays, and variables. The functionality provided within the components and the '~' may be combined into a smaller number of components and the '~' or further separated into additional components and the '~'. In addition, the components and '~' may be implemented to play one or more CPUs in the device or secure multimedia card. Also, in an embodiment, '~ unit' may include one or more processors.

Terms used to identify connection nodes, terms referring to network entities, terms referring to messages, terms referring to interfaces between network objects, and terms referring to various identification information used in the following description. Etc. are illustrated for convenience of description. Therefore, it is not limited to the terms used in the present disclosure, and other terms that refer to objects having equivalent technical meanings may be used.

For convenience of description below, the present disclosure uses terms and names defined in the specification for 5G or NR, LTE system in the disclosure. However, the present disclosure is not limited to these terms and names, and may be equally applied to systems conforming to other standards.

That is, in describing the embodiments of the present disclosure in detail, the communication standard set by the 3rd Generation Partnership Project (3GPP) will be the main target, but the main point of the present disclosure is also applicable to other communication systems having a similar technical background. Appropriate modifications may be made without departing from the scope of the present disclosure without departing from the scope of the present disclosure, which will be determined by those skilled in the art.

In the next generation mobile communication system (5G or NR system) in order to limit the complexity according to the physical downlink control channel (PDCCH) monitoring of the terminal to less than a certain number, the maximum number of PDCCH candidates and the maximum control channel element (CCE) There may be a limit on the number). If the UE is capable of Carrier Aggregation (CA) for four or more cells (or Component Carrier (CC) can also be used in the same sense), the UE monitors the PDCCH candidate group with the base station. Capability for the number of downlink cells N ^cap may be reported. The base station may set a control resource set and a search space in consideration of the capability reported from the terminal. In this case, when monitoring PDCCH for one or more cells by performing carrier aggregation, a method of determining a limit of the maximum number of PDCCH candidate groups and the maximum number of CCEs in each cell may be required.

According to an embodiment of the present disclosure, carrier aggregation is performed on cells configured with different subcarrier spacings, and a specific cell may schedule (ie, cross-schedule) another cell. In this case, a method of determining a limit of the maximum number of PDCCH candidates and the maximum number of CCEs may be proposed. The method according to the embodiment may include a method of determining based on a subcarrier interval of a cell to perform scheduling, a method of considering a subcarrier interval of a cell to which a scheduling is applied, and the like.

Wireless communication systems have moved away from providing earlier voice-oriented services, such as High Speed Packet Access (HSPA), Long Term Evolution (LTE) or Evolved Universal Terrestrial Radio Access (E-UTRA), LTE- Broadband that provides high-speed, high-quality packet data services such as communications standards such as Advanced (LTE-A), LTE-Pro, High Rate Packet Data (HRPD) in 3GPP2, Ultra Mobile Broadband (UMB), and IEEE 802.16e Evolving into a wireless communication system.

As a representative example of the above-mentioned broadband wireless communication system, an LTE system adopts an Orthogonal Frequency Division Multiplexing (OFDM) scheme in downlink (DL) and a single carrier frequency division in uplink (UL) Multiple Access). The uplink refers to a radio link through which a user equipment (UE) or mobile station (MS) transmits data or control signals to a base station (eNode B or base station (BS)). This refers to a wireless link that transmits data or control signals. In the above-described multiple access scheme, data or control information of each user can be distinguished by assigning and operating such that time-frequency resources for carrying data or control information for each user do not overlap each other, that is, orthogonality is established. have.

Next-generation mobile communication systems (5G or NR systems), which are future communication systems after LTE, should be able to freely reflect various requirements such as users and service providers, and therefore services that satisfy various requirements must be supported. Services considered for 5G communication systems include enhanced Mobile Broadband (eMBB), massive machine type communication (mMTC), Ultra Reliability Low Latency Communciation (URLLC), etc. There is this.

eMBB aims to provide a higher data rate than data rates supported by LTE, LTE-A, or LTE-Pro. For example, in a 5G communication system, an eMBB should be able to provide a peak data rate of 20 Gbps in downlink and a maximum transmission rate of 10 Gbps in uplink from one base station perspective. In addition, the next generation mobile communication system (5G or NR system) must provide the maximum transmission speed, and at the same time provide an increased user perceived data rate of the terminal. In order to meet such requirements, various transmission and reception techniques may be required, including an improved Multi Input Multi Output (MIMO) transmission technique. In addition, while transmitting signals using the maximum 20MHz transmission bandwidth in the 2GHz band used by the current LTE, 5G communication system uses a frequency bandwidth wider than 20MHz in the frequency band of 3 ~ 6GHz or 6GHz or more is required by 5G communication system It can satisfy the data transmission rate.

At the same time, mMTC is being considered to support application services such as the Internet of Thing (IoT) in next generation mobile communication systems (5G or NR systems). In mMTC, in order to efficiently provide the Internet of Things, it may be required to support connection of a large terminal in a cell, improve coverage of the terminal, improved battery time, and reduce the cost of the terminal. Since the IoT is attached to various sensors and various devices to provide a communication function, it must be able to support a large number of terminals (eg, 1,000,000 terminals / km 2) in a cell. In addition, due to the nature of the service, the terminal supporting mMTC is likely to be located in a shaded area that the cell does not cover, such as the basement of a building, thus providing more coverage than other services provided by next-generation mobile communication systems (5G or NR systems). You can ask. The terminal supporting the mMTC should be configured as a low-cost terminal, and because it is difficult to replace the battery of the terminal frequently, a very long battery life time (10-15 years) may be required.

Finally, in the case of URLLC, it may be a cellular-based wireless communication service used for a specific purpose (mission-critical). For example, remote control for robots or machinery, industrial automation, unmaned aerial vehicles, remote health care, emergency situations A service used for an emergency alert or the like may be considered. Thus, the communication provided by URLLC may have to provide very low latency and very high reliability. For example, a service supporting URLLC must satisfy an air interface latency of less than 0.5 milliseconds, and at the same time, may have a requirement of a packet error rate of 10-5 or less. Therefore, for services supporting URLLC, 5G systems must provide a smaller Transmit Time Interval (TTI) than other services, while at the same time designing a wide resource allocation in the frequency band to ensure the reliability of the communication link. May be required.

Three services of 5G, eMBB, URLLC, and mMTC can be multiplexed and transmitted in one system. In this case, different transmission / reception techniques and transmission / reception parameters may be used between services to satisfy different requirements of respective services.

Hereinafter, a frame structure of a next generation mobile communication system (5G or NR system) will be described in more detail with reference to the accompanying drawings.

1 is a diagram illustrating a basic structure of a time-frequency domain of a next generation mobile communication system according to an embodiment.

(도 1에서는 예시적으로 12로 도시되었다)개의 연속된 RE들은 하나의 자원 블록(Resource Block, RB, 104)을 구성할 수 있다. In FIG. 1, the horizontal axis represents the time domain and the vertical axis represents the frequency domain. In the time and frequency domain, the basic unit of the resource may be a resource element (RE, 101). The resource element 101 may be defined as one Orthogonal Frequency Division Multiplexing (OFDM) symbol 102 on the time axis and one Subcarrier 103 on the frequency axis. In the frequency domain

Consecutive REs (illustrated in FIG. 1 as 12 for example) may constitute one resource block (RB, 104).

2 is a diagram illustrating a frame, subframe, and slot structure of a next generation mobile communication system according to an embodiment.

2 illustrates an embodiment of a frame 200, a subframe 201, and a slot 202. In an embodiment, one frame 200 may be defined as 10 ms. In addition, one subframe 201 may be defined as 1ms, and thus, one frame 200 may include 10 subframes 201 in total.

)=14). 1 서브프레임(201)은 하나 또는 다수 개의 슬롯(202, 203)으로 구성될 수 있으며, 1 서브프레임(201)당 슬롯(202, 203)의 개수는 부반송파 간격에 대한 설정 값 μ(204, 205)에 따라 다를 수 있다. 도 2에서는 예시적으로, 부반송파 간격 설정 값으로 μ=0(204)인 경우와 μ=1(205)인 경우가 도시되어 있다. μ=0(204)일 경우, 1 서브프레임(201)은 1개의 슬롯(202)으로 구성될 수 있고, μ=1(205)일 경우, 1 서브프레임(201)은 2개의 슬롯(203)으로 구성될 수 있다. 즉 부반송파 간격에 대한 설정 값인 μ에 따라 1 서브프레임 당 슬롯 수(

)가 달라질 수 있고, 이에 따라 1 프레임 당 슬롯 수(

)가 달라질 수 있다. 각 부반송파 간격 설정 μ에 따른

및

는 아래의 표 1과 같이 정의될 수 있다.In an embodiment, one slot 202,203 may be defined with 14 OFDM symbols (i.e. number of symbols per slot (

) = 14). One subframe 201 may be composed of one or a plurality of slots 202 and 203, and the number of slots 202 and 203 per one subframe 201 is a set value μ (204, 205) for the subcarrier spacing. ) May vary. 2 exemplarily illustrates a case where μ = 0 (204) and μ = 1 (205) as subcarrier spacing values. If μ = 0 204, one subframe 201 may consist of one slot 202, and if μ = 1 205, one subframe 201 may be two slots 203. It may be configured as. That is, the number of slots per one subframe according to μ, the setting value for the subcarrier spacing (

) Can vary, so the number of slots per frame (

) May vary. For each subcarrier spacing μ

And

May be defined as shown in Table 1 below.

Hereinafter, a bandwidth part (BWP) setting of a next generation mobile communication system (5G or NR system) will be described in detail with reference to the accompanying drawings.

3 illustrates a BWP configuration of a next generation mobile communication system according to an exemplary embodiment.

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

In addition to the above-described configuration information, the base station may set various parameters related to the BWP to the terminal. The base station may deliver the above-described information to the terminal through higher layer signaling, for example, RRC signaling. At least one BWP may be activated among one or a plurality of configured BWPs. Whether to activate the configured BWP may be delivered from the base station to the terminal semi-statically through RRC signaling or dynamically through the DCI.

Before the RRC connection, the terminal may receive an initial BWP (Initial BWP) for initial access from the base station through a master information block (MIB). In more detail, the terminal may transmit a PDCCH to receive system information (remaining system information; RMSI or System Information Block 1; which may correspond to SIB1) required for initial access through the MIB in the initial access stage. It is possible to receive the setting information for the control area (Control Resource Set, CORESET) and the search space (Search Space). The control area and the search space, which are set as MIBs, may be regarded as IDs 0 respectively. The base station may notify the terminal of configuration information such as frequency allocation information, time allocation information, and numerology for the control region # 0 through the MIB. In addition, the base station may notify the terminal of the configuration information for the monitoring period and occasion for the control area # 0, that is, the configuration information for the search space # 0 through the MIB. The terminal may regard the frequency domain set as the control region # 0 obtained from the MIB as an initial BWP for initial access. At this time, the identifier ID of the initial BWP may be regarded as 0.

The configuration for the BWP supported by the aforementioned next generation mobile communication system (5G or NR system) can be used for various purposes.

In one embodiment, if the bandwidth supported by the terminal is smaller than the system bandwidth, the base station may support this through the above-described BWP configuration. For example, the base station may allow the terminal to transmit and receive data at a specific frequency position within the system bandwidth by setting the BWP position (setting information 2) of the above-mentioned [Table 2] to the terminal.

In another embodiment, the base station may set a plurality of BWP to the terminal to support different numerologies. For example, in order to support data transmission and reception using a subcarrier spacing of 15 kHz and a subcarrier spacing of 30 kHz to a specific terminal, the base station may set two BWPs to a subcarrier spacing of 15 kHz and 30 kHz, respectively. Different BWPs may be frequency division multiplexed. When data is to be transmitted and received at a specific subcarrier interval, the BWP set to the corresponding subcarrier interval may be activated.

In another embodiment, for the purpose of reducing power consumption of the terminal, the base station may set the BWP having a different size bandwidth to the terminal. For example, when the terminal supports a very large bandwidth, for example, a bandwidth of 100 MHz and always transmits and receives data in the corresponding bandwidth, very large power consumption may be caused. In particular, in the absence of traffic, monitoring unnecessary downlink control channels with a large bandwidth of 100 MHz may be very inefficient in terms of power consumption. In order to reduce power consumption of the terminal, the base station may set a relatively small bandwidth BWP, for example, 20 MHz BWP. In the absence of traffic, the UE may perform a monitoring operation at 20 MHz BWP, and when data is generated, may transmit and receive data to the 100 MHz BWP according to an instruction of the base station.

In the above-described method for configuring the BWP, UEs before RRC connection may receive configuration information on initial bandwidth part (BWP) through a master information block (MIB) in an initial access stage. In more detail, the UE controls a resource region for a downlink control channel through which downlink control information (DCI) for scheduling a system information block (SIB) can be transmitted from a MIB of a physical broadcast channel (PBCH). , CORESET) can be set. The bandwidth of the control region configured as MIB may be regarded as an initial BWP, and through the configured initial BWP, the terminal may receive a PDSCH through which SIB is transmitted. In addition to receiving the SIB, the initial BWP may be used for other system information (OSI), paging, and random access.

Hereinafter, an SS (Synchronization Signal) / PBCH block in a next generation mobile communication system (5G or NR system) will be described.

The SS / PBCH block refers to a physical layer channel block including a primary SS (PSS), a secondary SS (SSS), and a PBCH. More specifically, the SS / PBCH block may be defined as follows.

PSS: As a signal for downlink time / frequency synchronization, some information of a cell ID may be provided.

SSS: It is a standard of downlink time / frequency synchronization and provides remaining cell ID information not provided by the PSS. In addition, it may serve as a reference signal for demodulation of the PBCH.

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

SS / PBCH block: The SS / PBCH block may be a combination of PSS, SSS and PBCH. One or more SS / PBCH blocks may be transmitted within 5ms, and each SS / PBCH block transmitted may be identified by an index.

The terminal may detect the above-mentioned PSS and SSS in the initial access step, and may decode the PBCH. The UE may acquire the MIB from the PBCH, and receive the control region # 0 therefrom. The UE may assume that the selected SS / PBCH block and the demodulation RS (DMRS) transmitted in the control region # 0 are quasi co-located (QCL), and may perform monitoring on the control region # 0. The terminal may receive system information with downlink control information transmitted from the control region # 0. The UE may acquire configuration information related to a random access channel (RACH) required for initial access from the received system information. The terminal may transmit a Physical RACH (PRACH) to the base station in consideration of the SS / PBCH index selected by the terminal, and the base station receiving the PRACH may obtain information on the SS / PBCH block index selected by the terminal. From this, the base station can know the fact that the terminal has selected which of the SS / PBCH blocks and monitor the control region # 0 associated with it.

Hereinafter, downlink control information (hereinafter referred to as DCI) of a next generation mobile communication system (5G or NR system) will be described in detail.

Uplink data (or physical uplink shared channel (PUSCH)) or downlink data (or physical downlink shared channel (PDSCH)) in a next generation mobile communication system (5G or NR system) Scheduling information for may be delivered from the base station to the terminal through the DCI. The UE may monitor the DCI format for fallback and the DCI format for non-fallback with respect to the PUSCH or PDSCH. The countermeasure DCI format may be configured with a fixed field selected between the base station and the terminal, and the non-preparation DCI format may include a configurable field.

The above-described DCI may be transmitted through a physical downlink control channel (PDCCH) which is a physical downlink control channel through channel coding and modulation. A cyclic redundancy check (CRC) may be attached to the DCI message payload, and the CRC may be scrambled with a Radio Network Temporary Identifier (RNTI) corresponding to the identity of the terminal. Different RNTIs may be used depending on the purpose of the DCI message, for example, UE-specific data transmission, power control command or random access response. That is, the RNTI may be transmitted in a CRC calculation process without being explicitly transmitted. Upon receiving the DCI message transmitted on the PDCCH, the UE may check the CRC using the allocated RNTI. If the CRC check result is correct, the UE may know that the corresponding message is transmitted to the above-described UE.

For example, the DCI scheduling the PDSCH for the system information (SI) may be scrambled with the SI-RNTI. The DCI scheduling the PDSCH for the RAR message may be scrambled with the RA-RNTI. The DCI scheduling the PDSCH for the paging message may be scrambled with the P-RNTI. The DCI for notifying the slot format indicator (SFI) may be scrambled with the SFI-RNTI. The DCI for notifying transmit power control (TPC) may be scrambled with the TPC-RNTI. DCI scheduling UE-specific PDSCH or PUSCH may be scrambled with C-RNTI (Cell RNTI).

DCI format 0_0 may be used as a countermeasure DCI for scheduling a PUSCH, where the CRC may be scrambled with C-RNTI. In an embodiment, the DCI format 0_0 in which the CRC is scrambled with the C-RNTI may include the following information.

DCI format 0_1 may be used as a non-preparative DCI for scheduling PUSCH, where CRC may be scrambled with C-RNTI. In an embodiment, DCI format 0_1 in which CRC is scrambled with C-RNTI may include the following information.

DCI format 1_0 may be used as a countermeasure DCI for scheduling PDSCH, where CRC may be scrambled with C-RNTI. In an embodiment, the DCI format 1_0 in which the CRC is scrambled with the C-RNTI may include the following information.

DCI format 1_1 may be used as a non-preparative DCI scheduling a PDSCH, where the CRC may be scrambled with C-RNTI. In an embodiment, DCI format 1_1 in which CRC is scrambled with C-RNTI may include the following information.

Hereinafter, a downlink control channel in a next generation mobile communication system (5G or NR system) will be described in more detail with reference to the accompanying drawings.

4 is a diagram illustrating a control region setting of a downlink control channel of a next generation mobile communication system according to an embodiment. More specifically, FIG. 4 is a diagram illustrating an embodiment of a control area (Control Resource Set, CORESET) in which a downlink control channel is transmitted in a 5G wireless communication system.

Referring to FIG. 4, two control regions (control region # 1 401 and control region # 2 402) may be set in one slot 420 on the time axis of the BWP 410 of the terminal on the frequency axis. have. The control regions 401 and 402 may be set to specific frequency resources 403 within the entire terminal BWP 410 on the frequency axis. The control regions 401 and 402 may be set to one or a plurality of OFDM symbols on the time axis, which may be defined as a control region length (404). In FIG. 4, for example, the control region # 1 401 is set to a control region length of 2 symbols, and the control region # 2 402 is set to a control region length of 1 symbol.

The base station sets the control area of the next generation mobile communication system (5G or NR system) to the terminal through higher layer signaling (for example, system information, master information block (MIB), and radio resource control (RRC) signaling). Can be. Setting the control region to the terminal may mean providing information such as a control region identifier, a frequency position of the control region, a symbol length of the control region, and the like. In an embodiment, the control region setting may include the following information.

In [Table 7], tci-StatesPDCCH (hereinafter, referred to as 'TCI state') configuration information includes one or more SS (Synchronization Signal) / PBCHs having a QCL (Quasi Co Located) relationship with DMRS transmitted from a corresponding control region. (Physical Broadcast Channel) may include information of a block index or a channel state information reference signal (CSI-RS) index.

5 is a diagram illustrating a structure of a downlink control channel of a next generation mobile communication system according to an embodiment. More specifically, FIG. 5 illustrates a basic unit of time and frequency resources constituting a downlink control channel that can be used in 5G according to an embodiment. Referring to FIG. 5, a basic unit of time and frequency resources constituting a control channel may be defined as a resource element group (REG) 503. In addition, the REG 503 may be defined by one OFDM symbol 501 on the time axis and one Physical Resource Block 502 on the frequency axis, that is, 12 subcarriers. In an embodiment, the REG 503 may be concatenated to configure a downlink control channel allocation unit.

As shown in FIG. 5, when a basic unit to which a downlink control channel is allocated in 5G is referred to as a control channel element (CCE) 504, one CCE 504 may include a plurality of REGs 503. For example, referring to the REG 503 illustrated in FIG. 5, the REG 503 may include 12 REs. That is, in FIG. 5, if one CCE 504 consists of six REGs 503, one CCE 504 may consist of 72 REs. When the downlink control region is set, the corresponding region may be composed of a plurality of CCEs 504, and the specific downlink control channel is divided into one or a plurality of CCEs 504 according to an aggregation level (AL) in the control region. It can be mapped and sent. The CCEs 504 in the control region are divided by numbers, which may be assigned according to a logical mapping scheme.

The basic unit of the downlink control channel illustrated in FIG. 5, that is, the REG 503 may include both REs to which DCI is mapped and a region to which DMRS 505, which is a reference signal for decoding it, is mapped. As shown in FIG. 5, three DMRSs 505 may be transmitted in one REG 503.

The number of CCEs required to transmit the PDCCH may be variable depending on an aggregation level (AL), for example, 1, 2, 4, 8, 16, and the number of different CCEs may be linked to a downlink control channel. Can be used to implement link adaptation. For example, when AL = L, one downlink control channel may be transmitted through L CCEs.

The UE needs to detect a signal without knowing information about a downlink control channel, and may define a search space indicating a set of CCEs for blind decoding. The search space is a set of downlink control channel candidate groups (Candidates) consisting of CCEs that the UE should attempt to decode on a given aggregation level. Since there are various aggregation levels that make one bundle from 1, 2, 4, 8, and 16 CCEs, the UE may have a plurality of search spaces. A search space set may be defined as a set of search spaces at all set aggregation levels.

The search space may be classified into a common search space and a UE-specific search space. In an embodiment, a certain group of terminals or all terminals may examine the common search space of the PDCCH to receive cell common control information such as dynamic scheduling or paging messages for system information. For example, the UE may receive PDSCH scheduling allocation information for transmission of the SIB including carrier information of the cell by examining the common search space of the PDCCH. In the case of the common search space, since a certain group of terminals or all terminals must receive the PDCCH, it can be defined as a set of the promised CCE. On the other hand, the UE may receive the scheduling assignment information for the UE-specific PDSCH or PUSCH by examining the UE-specific search space of the PDCCH. The terminal-specific search space may be terminal-specifically defined as a function of the terminal's identity and various system parameters.

In 5G, the parameter for the search space for the PDCCH may be set from the base station to the terminal through higher layer signaling (eg, SIB, MIB, RRC signaling). In an embodiment, the base station determines the number of PDCCH candidate groups at each aggregation level L, the monitoring period for the search space, the monitoring occasion in the symbol unit in the slot for the search space, and the search space type (common search space or terminal-specific search space). , The combination of the DCI format and RNTI to be monitored in the corresponding search space, the control region index to monitor the search space, and the like can be set to the UE. In an embodiment, the above-described setting may include the following information.

Based on the above configuration information, the base station may set one or a plurality of search space sets in the terminal. In an embodiment, the base station may set the search space set 1 and the search space set 2 to the UE, or set to monitor the DCI format A scrambled by the X-RNTI in the search space set 1 in the common search space, and the search space set. DCI format B scrambled with Y-RNTI at 2 may be configured to be monitored in the UE-specific search space.

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

In the common search space, a combination of the following DCI format and RNTI can be monitored.

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

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

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

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

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

In the UE-specific search space, a combination of the following DCI format and RNTI may be monitored.

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

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

The stated RNTIs may follow the definitions and uses listed below.

C-RNTI (Cell RNTI): UE-specific PDSCH scheduling use

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

Configured Scheduling RNTI (CS-RNTI): Semi-statically configured UE-specific PDSCH scheduling use

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

P-RNTI (Paging RNTI): PDSCH scheduling for which paging is transmitted.

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

-INT-RNTI (Interruption RNTI): To inform whether or not pucturing for PDSCH

TPC-PUSCH-RNTI (Transmit Power Control for PUSCH RNTI): Use of power control command indication for PUSCH

TPC-PUCCH-RNTI (Transmit Power Control for PUCCH RNTI): Indication of power control command for PUCCH

TPC-SRS-RNTI (Transmit Power Control for SRS RNTI): To indicate power regulation command for SRS

In an embodiment, the above-described DCI formats may be defined as follows.

In 5G, a plurality of search space sets may be set to different parameters (eg, parameters of Table 8). Therefore, at each time point, the set of search space sets monitored by the terminal may vary. For example, if search space set # 1 is set to the X-slot period, search space set # 2 is set to the Y-slot period, and X and Y are different, the terminal searches for search space set # 1 and search space set # in a specific slot. You can monitor both, and you can monitor either Searchspace Set # 1 or Searchspace Set # 2 in a particular slot.

When a plurality of search space sets are configured for the terminal, the following conditions may be considered to determine the search space set that the terminal should monitor.

[Condition 1: Limit Maximum Number of PDCCH Candidates]

The number of PDCCH candidate groups that can be monitored per slot may not exceed M ^μ . M ^μ may be defined as the maximum number of PDCCH candidate groups per slot in a cell set to a subcarrier interval of 15 · 2 ^μ kHz, and may be defined as shown in Table 10 below.

[Condition 2: Limit Maximum Number of CCEs]

The number of CCEs constituting the total search space per slot (where the total search space may mean an entire CCE set corresponding to a union region of a plurality of search space sets) does not exceed C ^μ . C ^μ may be defined as the maximum number of CCEs per slot in a cell set to a subcarrier interval of 15 · 2 ^μ kHz, and may be defined as shown in Table 11 below.

For convenience of description, a situation in which both of the above-described conditions 1 and 2 are satisfied at a specific time point is exemplarily defined as “condition A”. Therefore, not satisfying condition A may mean not satisfying at least one of the above-described conditions 1 and 2.

Depending on the setting of the search space sets of the base station, a case may occur in which the above-described condition A is not satisfied at a specific time point. If the condition A described above is not satisfied at a specific time point, the UE may select and monitor only a part of the search space sets configured to satisfy the condition A at that time point, and the base station transmits the PDCCH to the selected search space set. Can be.

In an embodiment, the method of selecting some search spaces from the entire set of search spaces may include the following methods.

[Method 1]

If condition A for PDCCH is not satisfied at any point (slot),

The terminal (or the base station) may preferentially select a search space set in which a search space type is set as a common search space among search space sets existing at a corresponding point of time than a search space set configured as a terminal-specific search space.

If all of the search space sets set as the common search space are selected (that is, if condition A is satisfied even after selecting all the search spaces set as the common search space), the terminal (or the base station) is a terminal-specific search space. You can select search space sets that are set to. In this case, when there are a plurality of search space sets configured as a terminal-specific search space, a search space set having a low search space set index may have a higher priority. In consideration of the priority, the UE or the base station may select the UE-specific search space sets within a range where condition A is satisfied. That is, the UE may monitor some search space sets selected within the range where condition A is satisfied among the set total search space sets, and the base station may search for some selected searches within the range where condition A is satisfied among the set search space sets. The PDCCH of the UE may be transmitted in space sets.

Hereinafter, a method of determining the maximum PDCCH candidate group limit and the maximum CCE number limit in an environment operating with carrier aggregation (CA) will be described in detail.

If the UE is capable of carrier aggregation for four or more cells (or Component Carriers (CCs)), the UE has a capability for the number of downlink cells (N ^cap ) capable of monitoring the PDCCH candidate group with the base station. Capability can be reported.

In an embodiment, the terminal receives a cell configured with a total number of N ^μ subcarrier intervals from the base station, and the set cells are self-scheduled (where self-scheduling refers to control information indicating scheduling for a data channel and a corresponding channel). It is assumed that the control information corresponds to a cell operating in a transmission / reception of a scheduled data channel, which can be defined as an operation performed in the same cell. In this case, the UE may consider the PDCCH candidate group limit (M ^{total, μ} ) and the CCE number limit (C ^{total, μ} ) for the configured N ^μ cells as shown in [Equation 1] and [Equation 2].

이다. 예시적으로, [수학식 1]과 [수학식 2]의 M^total,μ 및 C^total,μ을 "제1제한"으로 정의한다. 즉, 제1제한은 서브캐리어 간격 μ로 설정된 하나 또는 복수 개의 셀들에 대하여 적용될 수 있는 최대 PDCCH 후보군 수 및 최대 CCE 수에 대한 제한을 의미할 수 있다. In [Equation 1] and [Equation 2] described above,

to be. For example, M ^{total, μ} of [Equation 1] and [Equation 2]. And C ^{total, μ} is defined as the "first limit." That is, the first limitation may mean a restriction on the maximum number of PDCCH candidate groups and the maximum number of CCEs that can be applied to one or a plurality of cells set to a subcarrier interval μ.

The terminal may receive a set of search spaces from the base station, at which time it can be expected not to exceed the first limit. That is, the terminal can be expected to monitor the search space consisting of the number of PDCCH candidate group of the maximum M ^{total, μ} and the number of CCE of the maximum C ^{total, μ} . The base station may set the search space sets so that the search space sets set in the cells in which the subcarrier interval is set to μ do not exceed the first limit. That is, the base station may configure the terminal so that the total number of PDCCH candidate groups constituting the search space sets set in the cells set to the subcarrier interval μ does not exceed M ^{total, μ} and the total CCE number does not exceed C ^{total, μ} .

Also illustratively, M ^{μ in} Table 10 and C ^μ in Table 11 are defined as “second limit”. That is, the second limit may mean a limit on the maximum number of PDCCH candidate groups and the maximum number of CCEs that can be applied to a specific cell set to a subcarrier interval μ. In setting the search space set for a specific cell, the base station may notify the UE of a search space setting exceeding the second limit (that is, when the condition A described above is not satisfied) at a specific time. The terminal may exceed the second limit when monitoring the search space of a specific cell at a specific time according to the search space setting of the base station. In this case, the terminal may selectively monitor a specific search space set based on the procedure of [Method 1] described above.

In an embodiment, the base station may set the search space set so that the secondary cell does not always exceed the second limit. The UE can expect the secondary cell to always set the search space set not exceeding the second limit.

If the UE is capable of carrier aggregation for four or more cells (or Component Carriers (CCs)), the UE has a capability for the number of downlink cells (N ^cap ) capable of monitoring the PDCCH candidate group with the base station. Capability can be reported.

Controlled scheduling is, instructions for scheduling on the data channel - By way of example, the UE had a total of N ^μ subcarriers interval from the base station to set the cell is set to μ, a cross with respect to the set total N ^μ cells - scheduling (where cross The cell where information is transmitted and the cell that transmits and receives the data channel scheduled by the control information can be defined as an operation performed in different cells), and the subcarrier intervals of the cells where cross-scheduling is performed are the same. Assume that they correspond to cells set to μ. In this case, the UE may consider the PDCCH candidate group limit (M ^{total, μ} ) and the CCE number limit (C ^{total, μ} ) as shown in Equation 3 and Equation 4 with respect to the set N ^μ cells. have.

6 is a diagram for describing a method of determining a maximum number of PDCCH candidate groups in a next generation mobile communication system according to an embodiment. More specifically, FIG. 6 is a diagram illustrating an embodiment to which the maximum number of PDCCH candidates and the maximum number of CCEs are applied in a carrier aggregation environment. In FIG. 6, self scheduling is considered.

이다. Referring to FIG. 6, a total of six cells (CC # 1 601, CC # 2 602, CC # 3 603, CC # 4 604, CC # 5 605, and CC # 6 ( 606). In the embodiment, CC # 1 601, CC # 2 602, CC # 3 603 are set to subcarrier spacing mu = 0 (ie 15 kHz), CC # 4 604, CC # 5 605 is set to subcarrier spacing mu = 1 (ie 30 kHz), and CC # 6 606 is set to subcarrier spacing mu = 2 (ie 60 kHz). Thus, in FIG. 6 by way of example,

to be.

The UE may report to the base station an N ^cap value that is a capability of the number of downlink cells capable of monitoring the PDCCH candidate group. For example, it is assumed that N ^cap = 4 in FIG. 6.

For cells CC # 1 601, CC # 2 602, and CC # 3 603 having μ = 0, a first limit value for the number of PDCCH candidate groups may be calculated as shown in Equation 5 below. .

For cells CC # 4 604 and CC # 5 605 having μ = 1, a first limit value for the number of PDCCH candidate groups may be calculated as shown in Equation 6 below.

For cells CC # 6 606 having μ = 2, a first limit value for the number of PDCCH candidate groups may be calculated as shown in Equation 7 below.

Referring to [Table 10], for the cells CC # 1 601, CC # 2 602, and CC # 3 603 having μ = 0, the second limit value for the number of candidate PDCCH groups is M ⁰ = 44, The second limit value for the number of PDCCH candidate groups for the cells CC # 4 604 and CC # 5 605 with μ = 1 is PDCCH candidate group for the cells CC # 6 606 with M ¹ = 36 and μ = 2. The second limit value for the number may be determined as M ² = 22.

Meanwhile, in the present embodiment, the limit value for the number of PDCCH candidate groups has been described as an example, but the CCE number limit (C ^{total, μ} ) may also be calculated by the same method.

As described above, in an embodiment, the present disclosure relates to a cell performing scheduling (ie, downlink control information for scheduling is transmitted in an environment operating in carrier aggregation in 5G and also in an environment operating in cross-scheduling). A cell to which the UE performs monitoring for the PDCCH and a cell to which scheduling is applied (that is, a cell in which data channel transmission and reception occurs according to scheduling information of received downlink control information) or the same If the subcarrier spacing of the cell for transmitting and receiving data channels based on the downlink control information is different, it may include a method for determining the maximum PDCCH candidate group limit and the maximum CCE number limit.

In the following description, for the sake of brevity, a limit value (M ^{total, mu} ) for the number of PDCCH candidate groups will be exemplarily described. However, the present disclosure can be equally applied to calculating the CCE number limit value (C ^{total, μ} ).

For simplicity of description in describing the present disclosure, a cell for performing scheduling is defined as a "first cell" and a cell to which scheduling information of the "first cell" is applied is defined as a "second cell".

Hereinafter, embodiments of the present disclosure will be described in detail with the accompanying drawings. Although the embodiment of the present disclosure has been described as an example based on a 5G system, the embodiment of the present disclosure may be applied to other communication systems having a similar technical background or channel form. For example, this may include LTE or LTE-A mobile communication and mobile communication technology developed after 5G. Accordingly, embodiments of the present disclosure may be applied to other communication systems through some modifications without departing from the scope of the present disclosure by the judgment of those skilled in the art.

In the description of the present disclosure, when it is determined that a detailed description of a related function or configuration may unnecessarily obscure the subject matter of the present disclosure, the detailed description thereof will be omitted. In addition, terms to be described below are terms defined in consideration of functions in the present disclosure, and may vary according to a user's or operator's intention or custom. Therefore, the definition should be made based on the contents throughout the specification.

<First Embodiment>

In the first embodiment of the present disclosure, the maximum PDCCH candidate group limit may be determined based on the subcarrier interval of the “first cell”.

More specifically, if the UE can perform carrier aggregation for four or more cells, the UE may report the capability for the number of downlink cells (N ^cap ) capable of monitoring the PDCCH candidate group to the base station.

으로 정의될 수 있다. 여기서 N^μ는 서브캐리어 간격이 μ로 설정된 셀의 개수를 의미할 수 있다. 각 셀들은 셀프-스케쥴링 또는 크로스-스케쥴링으로 설정되어 동작될 수 있다. 크로스-캐리어 스케쥴링으로 설정된 셀들은 서브캐리어 간격이 서로 다를 수 있다. 즉, "제1셀"의 서브캐리어 간격을 μ₁이라 하고, "제2셀"의 서브캐리어 간격을 μ₂라고 하였을 경우, μ₁ ≠ μ₂ 일 수 있다. The terminal may receive a plurality of cells for the purpose of carrier aggregation. For example, the terminal may receive a ^total of N ^total cells from the base station, where N ^total is

It can be defined as. Here, N ^μ may refer to the number of cells in which the subcarrier spacing is set to μ. Each cell may be configured and operated in self-scheduling or cross-scheduling. Cells configured for cross-carrier scheduling may have different subcarrier spacings. That is, when the subcarrier spacing of the "first cell" is referred to as μ ₁ and the subcarrier spacing of the "second cell" is referred to as μ ₂ , μ ₁ ≠ μ ₂ days Can be.

In this case, in the method for calculating a first limit (ie, the maximum number of PDCCH candidate groups that can be applied to one or a plurality of cells in which the subcarrier interval is set to μ), cross-scheduling is performed. is the sub-carrier interval of ₂ μ "second cell" is applied cross-it can be calculated by considering the subcarrier interval μ ₁ of the "first cell" to perform scheduling. That is, M ^{total, μ} may be calculated as shown in [Equation 8].

로 정의될 수 있으며,

은 셀프-스케쥴링이 적용되는 서브캐리어 간격이 μ인 셀의 수로 정의될 수 있고,

는 크로스-스케쥴링이 적용되는 "제2셀"에 해당하는 셀들 중에서, 해당하는 "제1셀"의 서브캐리어 간격이 μ인 셀들의 총 수로 정의될 수 있다.here

Can be defined as

Can be defined as the number of cells with subcarrier spacing μ to which self-scheduling is applied,

May be defined as the total number of cells having a subcarrier spacing μ of the corresponding “first cell” among cells corresponding to the “second cell” to which cross-scheduling is applied.

Similarly, at this time, in the method of calculating the second limit (the maximum number of PDCCH candidate groups that can be applied to a specific cell set to the subcarrier spacing μ), the cross-scheduling is applied. It can be calculated by considering a sub-carrier interval of ₁ μ "for performing a scheduling of the subcarrier interval μ _2, a cross" first cell "second cell. That is, the value of M ^μ2 of the “second cell” may be regarded as M ^μ1 .

Since the UE may perform PDCCH monitoring for the "second cell" in the search space set in the "first cell", the limit on the maximum number of PDCCH candidate groups is based on the subcarrier interval of the "first cell". It may be desirable to calculate.

7 is a diagram for describing a method of calculating the maximum number of PDCCH candidate groups according to an embodiment. More specifically, FIG. 7 is a diagram for describing a method of calculating the maximum number of PDCCH candidate groups according to the first embodiment of the present disclosure.

이다. 단말은 기지국에게 PDCCH 후보군을 모니터링할 수 있는 하향링크 셀의 수에 대한 능력 N^cap 값을 보고할 수 있다. 도 7에서, 예시적으로 N^cap = 4를 가정한다.Referring to FIG. 7, a total of six cells (CC # 1 701, CC # 2 702, CC # 3 703, CC # 4 704, CC # 5 705, and CC # 6 ( 706) is set to be exemplary. CC # 1 701, CC # 2 702 and CC # 3 703 are set to the subcarrier spacing μ = 0 (that is, 15 kHz), and CC # 4 704 and CC # 5 (705). ) Is set to subcarrier spacing mu = 1 (ie, 30 kHz), and CC # 6 706 is set to subcarrier spacing mu = 2 (ie, 60 kHz). Thus, referring to FIG. 7, by way of example,

to be. The terminal may report the capability N ^cap value for the number of downlink cells capable of monitoring the PDCCH candidate group to the base station. In FIG. 7, assume N ^cap = 4 by way of example.

Referring to FIG. 7, for example, CC # 1 701, CC # 3 703, CC # 5 705, and CC # 6 706 are assigned to cells in which scheduling may be performed by self-scheduling. The CC # 2 702 and the CC # 4704 may correspond to a cell in which scheduling may be performed by cross-scheduling. In this case, the “first cell” for cross-scheduling the CC # 2 702 and the CC # 4 704 may be the CC # 1 701.

The subcarrier spacing of CC # 1 701, which is the "first cell", and CC # 2 702, which is the "second cell," are equal to mu ₁ = mu ₂ = mu = 0, and the CC is the "first cell." The subcarrier spacing of # 1 701 and CC # 4 704, which is the " second cell, " may be different from each other by mu ₁ = 0 and mu ₂ = 1, respectively. At this time, when calculating M ^{total, μ} according to the first embodiment of the present disclosure, the subcarrier spacing between CC # 2 702 and CC # 4 702 corresponding to "second cell" is set to "first cell." M ^{total, μ} can be calculated based on the subcarrier spacing of CC # 1 701 corresponding to " That is, the subcarrier spacing of CC # 4704 corresponding to the "second cell" different from the "first cell" and the subcarrier spacing can be regarded as mu = 0, and M ^{total, mu} can be calculated. That is, when calculating M ^{total, 0,} as shown in FIG. 7, including CC # 4 (704), the total CC # 1 (701), CC # 2 (702), CC # 3 (703), CC Four cells of # 4 704 may be considered (707), and one cell of CC # 5 705 may be included except for CC # 4 704 when calculating M ^{total, 1} 708, one cell of CC # 6 706 may be included when calculating M ^{total, 2} (709).

Based on Equation 9, M ^{total, μ} The value can be calculated as follows.

Similarly, the second restriction on CC # 4 704 is not determined as M ¹ in consideration of the subcarrier spacing mu = 1 of CC # 4 704 which is the "second cell", but CC # 4 704 M ⁰ may be determined in consideration of the subcarrier spacing μ = 0 of CC # 1701 corresponding to the “first cell” of.

The terminal may receive a set of search spaces for each cell from the base station, and at this time, it may be expected not to exceed the first limit calculated based on the first embodiment. That is, the base station corresponds to cells having a subcarrier interval of μ while self-scheduling is performed to the terminal, and a “second cell” having a subcarrier interval of μ of a “first cell” that performs scheduling while cross-scheduling is performed. The total PDCCH candidate group constituting the search space sets set in the cells may be set not to exceed M ^{total, μ} .

In setting the search space set for a specific cell to the terminal, the base station sets a search space exceeding the second limit calculated based on the first embodiment described above (that is, does not satisfy the condition A described above). If applicable) can be notified. That is, the second limitation of the cells corresponding to the "second cell" to which the cross-scheduling is applied may be calculated from the subcarrier spacing of the "first cell" to cross-schedule the corresponding cell. The terminal may exceed the second limit when monitoring the search space of a specific cell at a specific time according to the search space setting of the base station. In this case, the terminal may selectively monitor the specific search space set based on the above-described procedure of [Method 1].

The base station may set the search space set so that the secondary cell does not always exceed the second limit. The UE can expect the secondary cell to always set the search space set not exceeding the second limit.

Second Embodiment

In the second embodiment of the present disclosure, the maximum PDCCH candidate group limit may be determined by dividing a set of cells for which cross-scheduling is performed and a set of cells for performing self-scheduling to calculate a first limit and a second limit, respectively. Further, in the embodiment, when calculating the first limit for the set of cells in which cross-scheduling is performed, the subcarrier interval and the "second cell" of the cell corresponding to the "first cell" among the cells in the set correspond to. A scaling factor Factor may be reflected in consideration of the ratio of subcarrier spacing of a cell.

More specifically, if the UE can perform carrier aggregation for four or more cells, the UE can report the capability of the number of downlink cells (N ^cap ) capable of monitoring the PDCCH candidate group to the base station. .

으로 정의될 수 있다. 여기서 N^μ는 서브캐리어 간격이 μ로 설정된 셀의 개수를 의미할 수 있다. 각 셀들은 셀프-스케쥴링 또는 크로스-스케쥴링으로 설정되어 동작될 수 있다. 크로스-캐리어 스케쥴링으로 설정된 셀들은 서브캐리어 간격이 동일하거나 또는 다를 수 있다. 즉, "제1셀"에 해당하는 셀의 서브캐리어 간격을 μ₁이라 하고, "제2셀"에 해당하는 셀의 서브캐리어 간격을 μ₂라고 하였을 경우, μ₁ ≠ μ₂ 일 수 있다. The terminal may receive a plurality of cells for the purpose of carrier aggregation. For example, the terminal may receive a ^total of N ^total cells from the base station, where N ^total is

It can be defined as. Here, N ^μ may refer to the number of cells in which the subcarrier spacing is set to μ. Each cell may be configured and operated in self-scheduling or cross-scheduling. Cells configured for cross-carrier scheduling may have the same or different subcarrier spacing. That is, when the subcarrier spacing of the cell corresponding to the "first cell" is called μ ₁ , and the subcarrier spacing of the cell corresponding to the "second cell" is defined as μ ₂ , μ ₁ ≠ μ ₂ Work Can be.

In an embodiment, the entire set of cells configured to perform carrier aggregation may be divided into a set of cells on which cross-scheduling is performed and a set of cells on which self-scheduling is performed. In this case, the cell corresponding to the “first cell” may be included in the set of cells where cross-scheduling is performed.

The cell corresponding to the "first cell" performing cross-scheduling may perform self-scheduling for itself as well as other cells corresponding to the "second cell". In this case, the cell corresponding to the "first cell" may be included in the set of cells in which cross-scheduling is performed even though self-scheduling is performed for itself. For simplicity, the set of cells in which cross-scheduling is performed is defined as a "first cell set" and the set of cells in which self-scheduling is performed as a "second cell set".

A method of calculating a first limit on a maximum number of PDCCH candidate groups for a "first cell set", the subcarrier interval of a cell corresponding to "the first cell" and a "second cell" among cells in the "first cell set"; Scaling factor may be reflected in consideration of the ratio of subcarrier spacing of the cell corresponding to the cell. For example, the first limit of the maximum number of PDCCH candidate groups for cells existing in the “first cell set” may be calculated as shown in Equation 10 below.

는 "제1셀집합" 내의 셀들 중에서 서브캐리어 간격이 μ인 셀의 총 수를 의미하고, μ₁은 "제1셀집합" 내의 "제1셀"에 해당하는 셀의 서브캐리어 간격에 해당할 수 있다. [수학식 10]에서 α^μ는 서브캐리어 간격이 μ인 셀에 적용하는 스케일링 인자에 해당한다. 예를 들어, "제1셀집합"내의 "제1셀"에 해당하는 셀의 서브캐리어 간격이 μ₁=0(즉 15kHz)일 때, 서브캐리어 간격이 μ=1(즉 30kHz)에 해당하는 "제1셀집합" 내의 셀들에 대하여 최대 PDCCH 후보군 수를 산출하는 과정에서, α=2에 해당하는 스케일링 인자를 곱하여 값을 도출할 수 있다.In Equation 10 above, N ^cap is the number of downlink cells capable of monitoring the PDCCH candidate group reported by the UE to the base station,

Denotes the total number of cells having a subcarrier spacing μ among the cells in the “first cell set”, and μ ₁ corresponds to the subcarrier spacing of the cell corresponding to the “first cell” in the “first cell set”. Can be. In Equation 10, α ^μ corresponds to a scaling factor applied to a cell having a subcarrier spacing μ. For example, when the subcarrier spacing of the cell corresponding to the "first cell" in the "first cell set" is μ ₁ = 0 (ie 15 kHz), the subcarrier spacing corresponds to μ = 1 (ie 30 kHz). In the process of calculating the maximum number of PDCCH candidate groups for cells in the “first cell set”, a value may be derived by multiplying a scaling factor corresponding to α = 2.

The reason for considering the scaling factor is that since the definition of the maximum number of PDCCH candidates per cell defined in Table 10 corresponds to the maximum number of PDCCH candidates per slot, the maximum number of PDCCH candidates for the same time interval (for example, 1 ms) is actually sub This is because the carrier spacing can vary greatly. The maximum number of PDCCH candidate groups per 1 ms according to each subcarrier interval is shown in Table 12 below.

That is, in consideration of the scaling factor, when the UE derives the maximum number of PDCCH candidate groups for each subcarrier interval based on the N ^cap value reported to the base station, the number of slots existing in the same time interval may be considered. This has the advantage of maximizing the scheduling flexibility of each cell while maximizing the possible blind decoding capabilities.

For example, when the subcarrier spacing of the cell corresponding to the "first cell" is smaller than the subcarrier spacing of the cell corresponding to the "second cell", for example, the "first cell" present in the "first cell set". It is assumed that the subcarrier spacing of the cell corresponding to "" is mu = 0 and the subcarrier spacing of the cell corresponding to "second cell" is mu = 1. Since the PDCCH monitoring for the "second cell" is performed in the "first cell", the subcarrier spacing of the PDCCH will follow [mu] = 0, which is the subcarrier spacing of the "first cell."

If the scaling factor is not considered, the maximum PDCCH candidate group limit of the cell corresponding to the "second cell" may be 36. In this case, since the subcarrier interval of the PDCCH is 15 kHz, the maximum PDCCH candidate group limit is 36 for 1 ms. Can be. However, as shown in [Table 12], since the maximum number of PDCCH candidates that can be monitored for 1 ms at 30 kHz may be 36 * 2 = 72, it may be limited to a relatively smaller maximum number of PDCCH candidates during the same time interval, which is soon to be achieved. Scheduling flexibility can be reduced. Therefore, even if the PDCCH is transmitted at 15 kHz, the maximum number of PDCCH candidate groups of a cell corresponding to a "second cell" whose scaling factor 2 is μ = 1 is calculated in consideration of the maximum possible number of PDCCH candidate groups during the unit time of the UE. May be more desirable to increase scheduling flexibility.

In another embodiment, when the subcarrier spacing of the cell corresponding to the "first cell" is greater than the subcarrier spacing of the cell corresponding to the "second cell", for example, the "first cell set" present in the "first cell set." Suppose that the subcarrier spacing of a cell corresponding to "cell" is mu = 1 and the subcarrier spacing of a cell corresponding to "second cell" is mu = 0. Since the PDCCH monitoring for the "second cell" is performed in the "first cell", the subcarrier spacing of the PDCCH follows the mu = 1 which is the subcarrier spacing of the "first cell".

If the scaling factor is not considered, the maximum PDCCH candidate group limit of the cell corresponding to the "second cell" may be 44. In this case, since the subcarrier interval of the PDCCH is 30 kHz, the maximum PDCCH candidate group number is 44 for 0.5 ms. That is, 1 ms corresponds to the maximum number of candidate PDCCH groups. However, as shown in Table 12, when the subcarrier interval is 15 kHz, since the maximum number of PDCCH candidate groups that can be monitored for 1 ms is 44, it corresponds to a relatively larger maximum number of PDCCH candidate groups during the same time interval. Therefore, considering the scaling for calculating the maximum possible number of PDCCH candidate groups for a unit time corresponding to 0.5 ms (length of one slot for 30 kHz) in consideration of the subcarrier interval 30 kHz of the PDCCH, it corresponds to the "second cell". It may be desirable to consider 44/2 = 22 rather than 44 as the maximum number of PDCCH candidates in a cell. As a result, when the subcarrier interval of the cell corresponding to the "first cell" is larger than the subcarrier interval of the cell corresponding to the "second cell", the maximum number of PDCCH candidate groups of the cell corresponding to the "second cell" for a unit time. The size of may be prevented from becoming too large, and thus, the UE may efficiently monitor the PDCCH.

로 산출될 수 있다. When calculating the second limit for the maximum number of PDCCH candidate groups for cells existing in the "first cell set", the scaling factor may be reflected in the same manner. That is, the second limit of the cell in which the subcarrier spacing in the "first cell set" is set to μ is

It can be calculated as

The first limit of the maximum number of PDCCH candidate groups for cells existing in the “second cell set” may be calculated as shown in Equation 11 below.

는 "제2셀집합" 내의 셀들 중에서 서브캐리어 간격이 μ인 셀의 총 수를 의미한다. "제2셀집합" 내에 존재하는 셀들에 대하여, 최대 PDCCH 후보군 수에 대한 제2제한은 스케일링 인자에 대한 고려를 하지 않고 그대로

와 동일할 수 있다.In Equation 11

Denotes the total number of cells of subcarrier spacing μ among the cells in the “second cell set”. For the cells present in the "second cell set", the second limit on the maximum number of PDCCH candidate groups remains as it is without considering the scaling factor.

May be the same as

8 is a diagram for describing a method of calculating the maximum number of PDCCH candidate groups according to another embodiment. More specifically, FIG. 8 is a diagram illustrating an embodiment of a method of calculating the maximum number of PDCCH candidate groups according to the second embodiment of the present disclosure.

이다. 단말은 기지국에게 PDCCH 후보군을 모니터링할 수 있는 하향링크 셀의 수에 대한 능력 N^cap 값을 보고할 수 있다. 도 8에서, 예시적으로 N^cap = 4를 가정한다.For example, in FIG. 8, a total of six cells (CC # 1 801, CC # 2 802, CC # 3 803, CC # 4 804, CC # 5 805, and CC # 6 (806)). CC # 1 801, CC # 2 802, and CC # 3 803 are set to subcarrier spacing μ = 0 (that is, 15 kHz), and CC # 4 804, CC # 5 (805). ) Is set to subcarrier spacing mu = 1 (ie, 30 kHz), and CC # 6 806 is set to subcarrier spacing mu = 2 (ie, 60 kHz). Thus, referring to FIG. 8, by way of example

to be. The terminal may report the capability N ^cap value for the number of downlink cells capable of monitoring the PDCCH candidate group to the base station. In FIG. 8, assume N ^cap = 4 by way of example.

Referring to FIG. 8, for example, CC # 1 801, CC # 3 803, CC # 5 805, and CC # 6 806 may be assigned to a cell in which scheduling may be performed by self-scheduling. CC # 2 802 and CC # 4 804 correspond to cells in which scheduling may be performed by cross-scheduling. In this case, the CC # 2 802 and CC # 4 804 cross each other. The scheduling “first cell” may be CC # 1 801. The subcarrier spacing between CC # 1 801, which is the "first cell", and CC # 2 802, which is "the second cell," is equal to mu ₁ = mu ₂ = mu = 0, and CC that is the "first cell". The subcarrier spacing of # 1 801 and CC # 4 804 which is the "second cell" may be different from each other by μ ₁ = 0 and μ ₂ = 1, respectively.

Based on the second embodiment of the present disclosure, in order to calculate the maximum number of PDCCH candidate groups, a cell (self-scheduling) and a set of cells in which cross-scheduling is performed (first cell set 840 of FIG. 8) are performed. It can be divided into a set (the second cell set 850 of FIG. 8). The first cell set 840 may include CC # 1 801, CC # 2 802, and CC # 4 804, and the second cell set 850 includes CC # 3 803 and CC #. 5 805 and CC # 6 806 may be included.

In the method for calculating the first limit 820 for the maximum number of PDCCH candidate groups for the "first cell set 840," according to Equation 10, among the cells in the "first cell set 840". Subcarrier spacing of cells corresponding to "first cell" (CC # 1 801) and subcarrier spacing of cells corresponding to "second cell" (CC # 2 802, CC # 4 804) By calculating the scaling factor in consideration of the ratio of, α ⁰ = 1, α ¹ = 2 can be calculated.

이고, 서브캐리어 간격이 μ=1인 셀의 수는

이다. 이에 따라 제1셀집합에 대한 제1제한(820)은 아래의 [수학식 12]와 같이 산출될 수 있다(807). Further, referring to FIG. 8, the number of cells in which the subcarrier spacing in the “first cell set 840” is μ = 0 is

And the number of cells with subcarrier spacing μ = 1

to be. Accordingly, the first limit 820 for the first cell set may be calculated as shown in Equation 12 below (807).

로 산출될 수 있다.In an embodiment, the scaling factor, α ^μ may also be considered in a method of calculating the second limit 830 for the maximum number of PDCCH candidate groups of cells in the “first cell set 840”, and CC # 1 (801). ), CC # 2 802, CC # 4 804, respectively.

It can be calculated as

가 될 수 있다. 따라서, 제1제한(820)은 아래의 [수학식 13]과 같이 산출될 수 있다.On the other hand, in the method of calculating the first limit 820 for the maximum number of PDCCH candidate groups for the "second cell set 850", it can be calculated according to [Equation 11] without considering the scaling factor. In this case, since there are one cell having μ = 0, one cell having μ = 1, and one cell having μ = 2 in the “second cell set 850”,

Can be Therefore, the first limit 820 may be calculated as shown in Equation 13 below.

이 될 수 있다.Meanwhile, the second limit 830 for the maximum number of PDCCH candidate groups of cells in the “second cell set 850” may also be calculated as defined in [Table 10] without considering the scaling factor, and CC # 3 803, CC # 5 805, and CC # 6 806, respectively.

This can be

를 넘지 않을 것을 기대할 수 있고, "제2셀집합" 내의 서브캐리어 간격이 μ인 셀들에 대하여

를 넘지 않을 것을 기대할 수 있다. 기지국은 단말에게 "제1셀집합" 내의 셀들에 대하여 탐색공간 세트들을 구성하는 총 PDCCH 후보군 수가

를 넘지 않도록 설정해줄 수 있고, "제1셀집합" 내의 서브캐리어 간격이 μ인 셀들에 대하여 탐색공간 세트들을 구성하는 총 PDCCH 후보군 수가

를 넘지 않도록 설정해줄 수 있다.In an embodiment, the terminal may receive a set of search spaces for each cell from the base station, and is calculated based on the second embodiment described above for each of the "first cell set" and the "second cell set." You can expect not to exceed the 1 limit. That is, the terminal may determine the maximum number of PDCCH candidate groups for all cells in the “first cell set”.

For cells with a subcarrier spacing μ in the " second cell set "

You can expect not to exceed. The base station determines the total number of PDCCH candidate groups constituting the search space sets for cells in the “first cell set” to the UE.

The number of PDCCH candidate groups constituting the search space sets for the cells having a subcarrier spacing μ in the “first cell set” may be set to not exceed.

You can set it to not exceed.

In setting the search space set for a specific cell, the base station sets the search space set configured with the number of PDCCH candidate groups exceeding the second limit calculated based on the above-described second embodiment at a specific time point (ie, the foregoing description). If a condition A is not satisfied). The terminal may determine whether the condition A is satisfied by applying different second limits depending on whether the cell to be monitored corresponds to the "first cell set" or the "second cell set."

The base station may set the search space set so that the secondary cell does not always exceed the second limit. The UE can expect the secondary cell to always set the search space set not exceeding the second limit.

<Example 2-1>

9 is a diagram illustrating an operation of a terminal according to an embodiment. More specifically, FIG. 9 is a diagram for describing an operation of a terminal according to embodiment 2-1 of the present disclosure.

In operation 901, the terminal may determine whether the cell to be monitored is a cell operating in cross-scheduling, that is, whether the cell corresponds to the "first cell set."

If the corresponding cell corresponds to the "first cell set", in step 902, the UE may apply an α ^μ M ^μ value in consideration of the scaling factor to the second limit on the maximum number of PDCCH candidate groups of the corresponding cell.

If the cell does not correspond to the "first cell set", in step 903, the UE may apply the M ^μ value without applying the scaling factor to the second limit on the maximum number of PDCCH candidate groups of the cell. .

In step 904, the UE may determine whether the maximum number of PDCCH candidate groups is exceeded based on the second limit value calculated for the cell. When monitoring the search space of a specific cell at a specific time according to the search space setting, if the second limit is exceeded, the terminal may selectively monitor the specific search space set based on the above-described procedure of [Method 1]. Can be.

Third Embodiment

In a third embodiment of the present disclosure, the terminal divides the set of cells on which cross-scheduling is performed and the set of cells on which self-scheduling is performed to determine the maximum PDCCH candidate number limit, respectively, the first limit and the second limit. Can be calculated. At this time, in order to calculate the first limit, the UE may first calculate a "per cell limit" for each cell set to carrier aggregation, and based on this value, the set of cells in which cross-scheduling is performed and self-scheduling The first limitation of the set of cells to be performed can be calculated.

은 아래의 [수학식 14]와 같이 정의될 수 있다.In an embodiment, the "per cell limit value" may be defined as a temporary value for the maximum number of PDCCH candidate groups determined in consideration of the capability N ^cap of the UE for each cell set to carrier aggregation. For example, "limit per cell" for the kth cell with the subcarrier spacing set to μ.

May be defined as in Equation 14 below.

은 서브캐리어 간격이 μ로 설정된 셀 그룹에 대한 최대 PDCCH 후보군 수(이하 "셀그룹당제한값"이라 한다)로 정의될 수 있다. 즉, "셀당제한값"은 서브캐리어 간격이 μ로 설정된 셀들에 대한 제한값을 서브캐리어 간격이 μ로 설정된 셀들의 수로 균등하게 나눈 값에 해당할 수 있다.In [Equation 14]

May be defined as the maximum number of PDCCH candidate groups (hereinafter, referred to as a "limit value per cell group") for a cell group in which the subcarrier interval is set to μ. That is, the "limit value per cell" may correspond to a value obtained by dividing a limit value for cells having a subcarrier interval of μ by the number of cells having a subcarrier interval of μ.

Based on the "per cell limit value" described above, the terminal may calculate a first limit of the set of cells on which cross-scheduling is performed and the set of cells on which self-scheduling is performed. In this case, when the first limit is calculated for the set of cells on which the cross-scheduling is performed, the UE corresponds to the subcarrier interval of the cell corresponding to the “first cell” among the cells in the set and corresponds to the “second cell”. The scaling factor may be reflected in consideration of the ratio of the subcarrier spacing of the cell.

More specifically, if the UE can perform carrier aggregation for four or more cells, the UE can report the capability of the number of downlink cells (N ^cap ) capable of monitoring the PDCCH candidate group to the base station. .

으로 정의될 수 있다. 여기서 N^μ는 서브캐리어 간격이 μ로 설정된 셀의 개수를 의미할 수 있다. The terminal may receive a plurality of cells for the purpose of carrier aggregation. For example, the terminal may receive a ^total of N ^total cells from the base station, where N ^total is

It can be defined as. Here, N ^μ may refer to the number of cells in which the subcarrier spacing is set to μ.

Each cell may be configured and operated in self-scheduling or cross-scheduling. Cells configured for cross-carrier scheduling may have the same or different subcarrier spacing. That is, when the subcarrier spacing of the cell corresponding to the "first cell" is called μ ₁ , and the subcarrier spacing of the cell corresponding to the "second cell" is defined as μ ₂ , μ ₁ ≠ μ ₂ Work Can be.

The entire set of cells configured to perform carrier aggregation may be divided into a set of cells on which cross-scheduling is performed and a set of cells on which self-scheduling is performed. In this case, the cell corresponding to the “first cell” may be included in the set of cells where cross-scheduling is performed. In an embodiment, the cell corresponding to the "first cell" performing cross-scheduling may perform self-scheduling for itself as well as other cells corresponding to the "second cell". In this case, the cell corresponding to the "first cell" may be included in the set of cells in which cross-scheduling is performed, even though self-scheduling is performed for itself. For simplicity, the set of cells in which cross-scheduling is performed is defined as a "first cell set" and the set of cells in which self-scheduling is performed as a "second cell set".

이 [수학식 14]에 기반하여 각각 산출될 수 있다.First for each cell set to carrier aggregation, the "per cell limit" for the kth cell where the subcarrier spacing is set to μ

Each of these may be calculated based on Equation 14.

와 "제1셀집합" 내의 셀들 중에서 "제1셀"에 해당하는 셀의 서브캐리어 간격과 "제2셀"에 해당하는 셀의 서브캐리어 간격의 비율을 고려한 스케일링 인자를 고려하여 산출될 수 있다. 예를 들어, "제1셀집합" 내에 존재하는 셀에 대하여 최대 PDCCH 후보군 수 제1제한은 아래의 [수학식 15]와 같이 산출될 수 있다.Next, in calculating the first limit for the maximum number of PDCCH candidate groups for the "first cell set", the first limit is the above-mentioned "limit per cell".

And a scaling factor in consideration of the ratio of the subcarrier spacing of the cell corresponding to the "first cell" and the subcarrier spacing of the cell corresponding to the "second cell" among the cells in the "first cell set". . For example, the first limit of the maximum number of PDCCH candidate groups for the cells existing in the “first cell set” may be calculated as shown in Equation 15 below.

In Equation 15, N ^cap denotes the number of downlink cells capable of monitoring the PDCCH candidate group reported by the terminal to the base station, and α ^μ corresponds to a scaling factor applied to a cell having a subcarrier interval μ. Corresponding.

For example, when the subcarrier spacing of the cell corresponding to the "first cell" in the "first cell set" is μ ₁ = 0 (ie 15 kHz), the subcarrier spacing corresponds to μ = 1 (ie 30 kHz). In the process of calculating the maximum number of PDCCH candidate groups for cells in the “first cell set”, the UE may derive a value by multiplying a scaling factor corresponding to α = 2.

로 산출될 수 있다.In an embodiment, when the UE calculates the second limit for the maximum number of PDCCH candidate groups for cells existing in the “first cell set”, the terminal may similarly reflect the above-described scaling factor. That is, the second limit of the cell in which the subcarrier spacing in the "first cell set" is set to μ is

It can be calculated as

을 이용하여 산출할 수 있다. 예컨대, 단말은 아래의 [수학식 16]과 같이 상술된 "셀당제한값"

을 이용할 수 있다.Or, for a cell existing in the "second cell set", the terminal sets the first limit of the maximum number of PDCCH candidate groups to the above-mentioned "limit per cell".

It can be calculated using. For example, the terminal may have the aforementioned "limit value per cell" as shown in Equation 16 below.

Can be used.

으로 결정될 수 있다.On the other hand, the second limit on the maximum number of PDCCH candidate groups for the cells present in the "second cell set" is as it is without considering the scaling factor.

Can be determined.

FIG. 10 is a diagram for describing a method of calculating the maximum number of PDCCH candidate groups according to another embodiment. FIG. More specifically, FIG. 10 is a diagram for describing an embodiment of a method of calculating the maximum number of PDCCH candidate groups according to the third embodiment of the present disclosure.

이다. 단말은 기지국에게 PDCCH 후보군을 모니터링할 수 있는 하향링크 셀의 수에 대한 능력 N^cap 값을 보고할 수 있다. 도 10에서, 예시적으로 N^cap = 4를 가정한다.Referring to FIG. 10, a total of six cells (CC # 1 (1001), CC # 2 (1002), CC # 3 (1003), CC # 4 (1004), CC # 5 (1005), and CC # 6 ( 1006)) is set as an example. CC # 1 (1001), CC # 2 (1002), and CC # 3 (1003) are set to subcarrier spacing μ = 0 (that is, 15 kHz), and CC # 4 (1004) and CC # 5 (1005). ), CC # 6 1006 is set to a subcarrier interval mu = 1 (ie, 30 kHz). Thus, referring to FIG. 10, by way of example,

to be. The terminal may report the capability N ^cap value for the number of downlink cells capable of monitoring the PDCCH candidate group to the base station. In FIG. 10, assume N ^cap = 4 by way of example.

Referring to FIG. 10, CC # 1 1001, CC # 3 1003, CC # 5 1005, and CC # 6 1006 correspond to cells in which scheduling may be performed by self-scheduling. # 2 1002 and CC # 4 1004 may correspond to a cell in which scheduling may be performed by cross-scheduling. In this case, the "first cell" for cross-scheduling the CC # 21002 and the CC # 41004 may be the CC # 11001. The subcarrier spacing of CC # 1 1001, which is a "first cell", and CC # 2 1002, which is a "second cell," is equal to mu ₁ = mu ₂ = mu = 0, and a CC that is a "first cell". The subcarrier spacing of # 1 1001 and CC # 4 1004 which is the "second cell" may be different from each other by μ ₁ = 0 and μ ₂ = 1, respectively.

At this time, according to the third embodiment of the present disclosure, when calculating the maximum number of PDCCH candidate groups, a set of cells on which cross-scheduling is performed (first cell set 1040 of FIG. 10) and self-scheduling are performed. It may be divided into a set of cells (second cell set 1050 of FIG. 10). The first cell set 1040 may include CC # 1 (1001), CC # 2 (1002), CC # 4 (1004), and the second cell set (1050) includes CC # 3 (1003) and CC #. 5 (1005), CC # 6 (1006) may be included.

은 아래의 [수학식 17]과 같이 산출될 수 있다.First, the limit per cell group (1060) for cells with subcarrier spacing μ = 0 and μ = 1.

May be calculated as shown in Equation 17 below.

From the above-described "limit per cell group value 1060", the "per limit per cell 1070" for each k-th cell whose subcarrier spacing is set to mu can be calculated as shown in Equation 18 below.

The terminal may calculate the first limit 1020 for the maximum number of PDCCH candidate groups for the first cell set 1040 from the calculated limit value per cell 1070. First, with respect to the scaling factor, the subcarrier spacing and the "second cell" of the cell (CC # 1 1001) corresponding to the "first cell" among the cells in the "first cell set 1040" according to [Equation 15]. When the scaling factor considering the ratio of the subcarrier spacing of the cells corresponding to the cell "CC # 2 1002 and CC # 4 1004" is calculated, α ⁰ = 1 and α ¹ = 2. Accordingly, the first limit 820 for the "first cell set 1040" may be calculated as shown in Equation 19 below (1007).

으로 산출될 수 있다.In the method for calculating the second limit 1030 for the maximum number of PDCCH candidate groups of cells in the “first cell set 1040”, the terminal may consider the scaling factor, α ^μ , where CC # 1 1001, CC # 2 (1002) and CC # 4 (1004) respectively

It can be calculated as.

Further, in the method of calculating the first limit 1020 for the maximum number of PDCCH candidate groups for the "second cell set 1050", the terminal does not consider the scaling factor and according to the above-described Equation 16, The first limit 1020 may be calculated as shown in Equation 20 below.

이 될 수 있다.In an embodiment, the second limit 1030 for the maximum number of PDCCH candidate groups of cells in the "second cell set 1050" may also be calculated as defined in Table 10 without considering the scaling factor, and CC # 3 (1003), CC # 5 (1005), CC # 6 (1006) respectively

This can be

를 넘지 않을 것을 기대할 수 있고, "제2셀집합" 내의 서브캐리어 간격이 μ인 셀들에 대하여

를 넘지 않을 것을 기대할 수 있다. The terminal may receive a set of search spaces for each cell from the base station, and does not exceed the first limit calculated based on the third embodiment described above for each of the "first cell set" and the "second cell set". You can expect not to. That is, the terminal may determine the maximum number of PDCCH candidate groups for all cells in the “first cell set”.

For cells with a subcarrier spacing μ in the " second cell set "

You can expect not to exceed.

를 넘지 않도록 설정해줄 수 있고, "제1셀집합" 내의 서브캐리어 간격이 μ인 셀들에 대하여 탐색공간 세트들을 구성하는 총 PDCCH 후보군 수가

를 넘지 않도록 설정해줄 수 있다.The base station determines the total number of PDCCH candidate groups constituting the search space sets for cells in the “first cell set” to the UE.

The number of PDCCH candidate groups constituting the search space sets for the cells having a subcarrier spacing μ in the “first cell set” may be set to not exceed.

You can set it to not exceed.

In setting the search space set for a specific cell to the terminal, the base station sets a search space set configured with the number of PDCCH candidate groups exceeding the second limit calculated based on the above-described third embodiment (that is, the above-described method). The condition A is not satisfied). The terminal may determine whether the condition A is satisfied by applying different second limits depending on whether the cell to be monitored corresponds to the “first cell set” or the “second cell set”. That is, the same operation as in the above-described second embodiment is applicable.

The base station may set the search space set so that the secondary cell does not always exceed the second limit. The UE can expect the secondary cell to always set the search space set not exceeding the second limit.

In the above-described first, second, and third embodiments, a method of calculating a limit value for the maximum number of PDCCH candidate groups has been described. However, this is merely an example, and the present disclosure provides a limit value for the maximum number of CCEs. The same may be applied to the calculation method.

Fourth Embodiment

Cells set to carrier aggregation may be set to one or more BWPs, and each subcarrier interval may be set for each BWP. In a fourth embodiment of the present disclosure, the maximum PDCCH candidate group number and the maximum CCE number are set when a plurality of subcarrier intervals are configured for one cell because cells configured as carrier aggregation are configured as one or more BWPs. It includes a method for determining the subcarrier interval of the cell to be assumed by the terminal to calculate the limit value.

[Method 1]

In an embodiment, the UE may regard the subcarrier interval of the currently active BWP for a specific cell as the subcarrier interval of the cell, and calculate the maximum PDCCH candidate group number and the maximum CCE number limit value based on this. . For example, BWP # 1 and BWP # 2 are set in cell A, the subcarrier spacing of BWP # 1 is μ1, the subcarrier spacing of BWP # 2 is μ2, and the BWP currently activated in cell A is BWP #. If 1, the terminal may regard the subcarrier spacing of cell A as μ1. The UE may determine the maximum PDCCH candidate group number and maximum CCE number limit value of the cell A based on this.

[Method 2]

In an embodiment, the UE may regard the largest (or smallest) subcarrier interval among the subcarrier intervals set for each BWP for a specific cell as the subcarrier interval of the corresponding cell, and based on the maximum PDCCH candidate group The number limit and the maximum CCE number limit can be calculated. For example, when the largest subcarrier interval is selected, BWP # 1 and BWP # 2 are set in cell A, the subcarrier spacing of BWP # 1 is μ1 = 0, and the subcarrier spacing of BWP # 2 is μ2 = 1. In this case, the UE may regard the subcarrier interval of cell A as μ2 = 1 regardless of the BWP currently activated in cell A. The UE may determine the maximum PDCCH candidate group number and maximum CCE number limit value of the cell A based on this.

[Method 3]

In an embodiment, the UE may regard the subcarrier interval set in the BWP to which the lowest index or the highest index is assigned for a specific cell as the subcarrier interval of the corresponding cell, and based on the maximum number of candidate PDCCH groups Limit and maximum CCE number limits can be calculated. For example, when BWP # 1 and BWP # 2 are set in cell A when the subcarrier interval of the BWP having the lowest index is selected, the UE determines whether BWP # 1 of BWP # 1 is independent of the BWP currently activated in cell A. The subcarrier spacing may be regarded as the subcarrier spacing of cell A. The UE may determine the maximum PDCCH candidate group number and maximum CCE number limit value of the cell A based on this.

To perform the above-described embodiments of the present disclosure, a transceiver, a memory, and a processor of the terminal and the base station are illustrated in FIGS. A transmission and reception method of a base station and a terminal for applying a method of transmitting and receiving downlink control channel and downlink control information in a 5G communication system corresponding to the above-described embodiment is shown. And the processor should operate according to the embodiment.

In detail, FIG. 11 is a block diagram illustrating an internal structure of a terminal according to an embodiment of the present disclosure. As shown in FIG. 11, a terminal of the present disclosure may include a processor 1101, a transceiver 1102, and a memory 1103. According to the aforementioned communication method of the terminal, the transceiver 1102, the memory 1103, and the processor 1101 of the terminal may operate. However, the components of the terminal are not limited to the above examples. For example, the terminal may include more components or fewer components than the aforementioned components. In addition, the transceiver 1102, the memory 1103, and the processor 1101 may be implemented in a single chip form.

The transceiver 1102 may transmit and receive signals with the base station. Here, the signal may include control information and data. To this end, the transceiver 1102 may be configured with an RF transmitter for up-converting and amplifying the frequency of the transmitted signal, and an RF receiver for low-noise amplifying and down-converting the received signal. However, this is only an embodiment of the transceiver 1102, and the components of the transceiver 1102 are not limited to the RF transmitter and the RF receiver. In addition, the transceiver 1102 may receive a signal through a wireless channel, output the signal to the processor 1101, and transmit a signal output from the processor 1101 through a wireless channel.

The memory 1103 may store programs and data necessary for the operation of the terminal. In addition, the memory 1103 may store control information or data included in a signal obtained from the terminal. The memory 1103 may be configured as a storage medium or a combination of storage media such as a ROM, a RAM, a hard disk, a CD-ROM, a DVD, and the like. In addition, the memory 1103 may be configured of a plurality of memories. In one embodiment, the memory 1103 may store a program for supporting beam based cooperative communication.

The processor 1101 may control a series of processes in which the terminal may operate according to the above-described embodiments of the present disclosure. For example, a method of calculating the maximum PDCCH candidate group limit and the maximum CCE number limit according to an exemplary embodiment of the present disclosure, and a monitoring operation for the PDCCH of the UE according to the present disclosure may be differently controlled.

12 is a block diagram illustrating an internal structure of a base station according to an embodiment of the present disclosure. As shown in FIG. 12, the base station of the present disclosure may include a processor 1201, a transceiver 1202, and a memory 1203. According to the communication method of the base station described above, the transceiver 1202, the memory 1203, and the processor 1201 of the base station may operate. However, the components of the base station are not limited to the above examples. For example, the base station may include more components or fewer components than the aforementioned components. In addition, the transceiver 1202, the memory 1203, and the processor 1201 may be implemented in a single chip form.

The transceiver 1202 may transmit and receive a signal with the terminal. The signal described above may include control information and data. To this end, the transceiver 1202 may be configured as an RF transmitter for up-converting and amplifying a frequency of a transmitted signal, and an RF receiver for low noise amplifying and down-converting a received signal. However, this is only an embodiment of the transceiver 1202, and the components of the transceiver 1202 are not limited to the RF transmitter and the RF receiver.

In addition, the transceiver 1202 may receive a signal through a wireless channel, output the signal to the processor 1201, and transmit a signal output from the processor 1201 through the wireless channel.

The memory 1203 may store programs and data necessary for the operation of the base station. In addition, the memory 1203 may store control information or data included in a signal obtained from a base station. The memory 1203 may be configured with a storage medium or a combination of storage media such as a ROM, a RAM, a hard disk, a CD-ROM, a DVD, and the like. The memory 1203 may also be composed of a plurality of memories. In one embodiment, the memory 1203 may store a program for supporting beam based cooperative communication.

The processor 1201 may control a series of processes to operate the base station according to the above-described embodiment of the present disclosure. For example, the method of calculating the maximum PDCCH candidate group limit and the maximum CCE number limit according to an exemplary embodiment of the present disclosure, and the control region and search space setting operation of the base station may be differently controlled.

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

If implemented in software, a computer readable storage medium or computer program product may be provided that stores one or more programs (software modules). One or more programs stored in a computer readable storage medium or computer program product are configured for execution by one or more processors in an electronic device. One or more programs include instructions that cause an electronic device to execute methods in accordance with embodiments described in the claims or specifications of this disclosure.

Such programs (software modules, software) may include random access memory, non-volatile memory including flash memory, Read Only Memory (ROM), and electrically erasable programmable ROM. (EEPROM: Electrically Erasable Programmable Read Only Memory), magnetic disc storage device, compact disc ROM (CD-ROM), digital versatile discs (DVDs) or other forms It can be stored in an optical storage device, a magnetic cassette. Or, it may be stored in a memory composed of some or all of these combinations. In addition, each configuration memory may be included in plural.

In addition, the program is accessed through a communication network composed of a communication network such as the Internet, an intranet, a local area network (LAN), a wide area network (WLAN), or a storage area network (SAN), or a combination thereof. It may be stored in an attachable storage device that is accessible. Such storage devices may be connected to devices that perform embodiments of the present disclosure through external ports. In addition, a separate storage device on the communication network may access a device that performs an embodiment of the present disclosure.

In the specific embodiments of the present disclosure described above, the components included in the present disclosure are expressed in the singular or plural, according to the specific embodiments presented. However, singular or plural expressions are selected to suit the circumstances presented for convenience of description, and the present disclosure is not limited to the singular or plural elements, and the constituent elements expressed in plural or singular may be used singularly or singularly. Even expressed components may be composed of a plurality.

On the other hand, the embodiments of the present disclosure disclosed in the specification and drawings are merely presented specific examples to easily explain the technical contents of the present disclosure and aid in understanding the present disclosure, and are not intended to limit the scope of the present disclosure. That is, it will be apparent to those skilled in the art that other modifications based on the technical spirit of the present disclosure can be implemented. In addition, each of the above-described embodiments may be combined with each other as necessary to operate. Embodiments may also be applied to other systems, such as LTE systems, 5G or NR systems, and the like.

Claims (1)

In the method for transmitting control information,
Setting a control region for the at least one terminal in consideration of a downlink control channel element to be searched by at least one terminal; And
Providing information about the set control area.

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