WO2019216715A1

WO2019216715A1 - Method and device for transmitting or receiving pdcch in wireless communication system

Info

Publication number: WO2019216715A1
Application number: PCT/KR2019/005669
Authority: WO
Inventors: 김태형; 김영범; 오진영; 최승훈
Original assignee: 삼성전자 주식회사
Priority date: 2018-05-11
Filing date: 2019-05-10
Publication date: 2019-11-14

Abstract

The present disclosure relates to a communication technique for converging a 5G communication system for supporting a higher data transfer rate beyond a 4G system with an IoT technology, and a system therefor. The present disclosure may be applied to intelligent services (for example, smart homes, smart buildings, smart cities, smart cars or connected cars, health care, digital education, retail business, security and safety-related services, etc.) on the basis of a 5G communication technology and an IoT-related technology. The present invention relates to a method for monitoring a control area by a terminal.

Description

Method and apparatus for transmitting / receiving PDCCH in wireless communication system

The present invention relates to a method and apparatus for transmitting and receiving a downlink control channel in a wireless communication system. The invention also relates to a method and apparatus for setting bandwidth portion.

In order to meet the increasing demand for wireless data traffic since the commercialization of 4G communication systems, efforts are being made to develop improved 5G communication systems or pre-5G communication systems. 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). 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 order to mitigate the path loss of radio waves in the ultra-high frequency band and increase the propagation distance of radio waves, beamforming, massive array multiple input / output (FD-MIMO), and FD-MIMO are used in 5G communication systems. Array antenna, analog beam-forming, and large scale antenna techniques are discussed. 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 The development of such technology is being done. In addition, in 5G systems, Hybrid FSK and QAM Modulation (FQAM) and Slide 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 (SCMA) are being developed.

Meanwhile, the Internet is evolving from a human-centered connection network in which humans create and consume information, and an Internet of Things (IoT) network that exchanges and processes information between distributed components such as things. The Internet of Everything (IoE) technology, which combines big data processing technology through connection with cloud servers and the like, is 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 can be provided that collect and analyze data generated from connected objects to create new value in human life. 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 information technology (IT) 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, technologies such as sensor network, machine to machine (M2M) and machine type communication (MTC) are implemented by techniques such as beamforming, MIMO, and array antenna, which are 5G communication technologies. will be. 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.

On the other hand, there is a need for a method for the terminal to monitor the control area.

An object of the present invention is to provide a method for the terminal to monitor the control area. It is also an object of the present invention to provide a method and apparatus for setting bandwidth portion.

According to an embodiment of the present invention, in a method of operating a terminal, receiving first information on the number of physical downlink control channel (PDCCH) candidates and second information on the number of control channel elements (CCEs) from a base station; If a failure occurs, transmitting a beam failure recovery (BFR) request message to the base station in the first slot to the base station, searching for a search area set of the first control area and a second control area related to the BFR in the second slot. Selecting a region set and monitoring control information for receiving a BFR response message in the search region set of the selected second control region, wherein the first control region and the second control in the second slot If the information on the PDCCH of the region does not satisfy at least one of the first condition according to the first information or the second condition according to the second information, the second agent. It is possible to provide a method characterized by selecting a search area set of a fish area first.

In addition, according to an embodiment of the present invention, in a terminal, it is connected to a transceiver and the transceiver, and the first information about the number of physical downlink control channel (PDCCH) candidate and the number of control channel elements (CCE) from the base station Receiving a second information and, when a connection failure occurs, transmits a beam failure recovery (BFR) request message to the base station in the first slot to the base station; A control unit for selecting a search region set of a related second control region and controlling to monitor control information for receiving a BFR response message in the selected search region set of the second control region, wherein the first slot in the second slot The information on the PDCCH of the first control region and the second control region may include at least one of a first condition according to the first information or a second condition according to the second information. If not satisfied, it is possible to provide a terminal characterized by preferentially selecting a search region set of the second control region.

In addition, according to an embodiment of the present invention, in the method of operation of the base station, transmitting first information on the number of physical downlink control channel (PDCCH) candidate and second information on the number of control channel element (CCE) to the terminal Receiving a beam failure recovery (BFR) request message from the terminal to the base station in a first slot, selecting a search region set of the first control region and a search region set of the second control region related to the BFR in a second slot And transmitting control information for receiving a BFR response message in a resource of a search region set of the selected second control region, wherein the PDCCH of the first control region and the second control region in the second slot If the information about does not satisfy at least one of the first condition according to the first information or the second condition according to the second information, the search area of the second control area may be reduced. It is possible to provide a method characterized in that the first priority is selected.

In addition, according to an embodiment of the present invention, in the base station, connected to the transceiver and the transceiver, the first information about the number of physical downlink control channel (PDCCH) candidate and the number of control channel elements (CCE) to the terminal Transmitting second information, receiving a beam failure recovery (BFR) request message from the terminal to the base station in a first slot, and searching for a second control region related to the BFR and a search region set of the first control region in the second slot A control unit for selecting a region set and transmitting control information for receiving a BFR response message from a resource of a discovery region set of the selected second control region, wherein the first control region and the If the information on the PDCCH of the second control region does not satisfy at least one of the first condition according to the first information or the second condition according to the second information, the second agent. A base station can be provided which selects a search area set of a predetermined area first.

According to an exemplary embodiment of the present disclosure, a method for efficiently monitoring a control region by a terminal and an apparatus therefor may be provided. In addition, according to an embodiment of the present invention can provide a method and apparatus for setting the bandwidth portion.

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

2 illustrates a frame, subframe, and slot structure in 5G.

3 is a diagram illustrating an example of bandwidth configuration in 5G.

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

5 illustrates a structure of a downlink control channel in 5G.

6 is a diagram illustrating a connection failure recovery procedure in 5G.

FIG. 7 is a diagram illustrating an example of reference signal configuration and control region configuration for a connection failure recovery procedure in 5G.

8 is a diagram illustrating a first embodiment of the present invention.

9 is a diagram illustrating Embodiment 1-1 of the present invention.

FIG. 10 is a diagram illustrating an example of bandwidth configuration in 5G. FIG.

11 is a diagram illustrating an example of setting a control region in 5G.

12 is a diagram illustrating an example of bandwidth configuration in 5G.

13 is a view showing a fourth embodiment of the present invention.

14 is a block diagram illustrating an internal structure of a terminal according to an embodiment of the present invention.

15 is a block diagram illustrating an internal structure of a base station according to an embodiment of the present invention.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. At this time, it should be noted that the same components in the accompanying drawings are represented by the same reference numerals as possible. In addition, detailed descriptions of well-known functions and configurations that may blur the gist of the present invention will be omitted.

In describing the embodiments herein, descriptions of technical contents that are well known in the technical field to which the present invention belongs and are not directly related to the present invention will be omitted. This is to more clearly communicate without obscure the subject matter of the present invention 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 fully reflect the actual size. The same or corresponding components in each drawing are given the same reference numerals.

Advantages and features of the present invention, and methods for achieving them will be apparent with reference to the embodiments described below in detail in conjunction with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but can be implemented in various forms. It is provided to fully convey the scope of the invention to those skilled in the art, and the present invention is defined only by the scope of the claims. Like reference numerals refer to like elements throughout.

At this point, 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 flow chart block (s). It creates a 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 'parts' may be combined into a smaller number of components and the 'parts' or further separated into additional components and the 'parts'. In addition, the components and '~' may be implemented to play one or more CPUs in the device or secure multimedia card.

In a 5G communication system, if a link quality between a base station and a terminal is not good, a link recovery procedure may be performed. If it is determined that the connection quality is not better than the predefined threshold, the terminal may transmit a BFR (Beam Failure Recovery) Request message to the base station. Control resource set to receive Physical Downlink Control Channel (PDCCH) for receiving Response message for BFR request message for a certain time after sending BFR request message Set; CORESET) can be monitored. In this case, the monitoring operation for the control area that has been previously monitored may vary depending on the operation of monitoring the specific control area (named control area-BFR) for receiving the response message for the BFR. For example, when monitoring both the control region _BFR and the existing control region at a specific time, it may exceed the maximum number of blind decoding or the number of CCEs. Accordingly, the terminal may selectively perform monitoring on a specific search space accordingly. The present invention proposes a method for monitoring the control area by the terminal after transmitting the BFR request message as a method for solving the above problem. In the present invention, the UE may control the monitoring operation for the control region differently according to whether a reference signal (RS) set for BFR determination is set from the base station. In addition, when simultaneously monitoring the control area-BFR and the existing control area, the search space set in the control area_BFR can be monitored first.

In the 5G communication system, a control region capable of transmitting a downlink control channel may be configured from a base station to a terminal through a master information block (MIB) or radio resource control (RRC) signaling transmitted through a physical broadcast channel (PBCH). The identifier ID may be assigned to '0' in the control area set to the MIB. The control area set to the MIB may be set to different parameters from the control area set to the RRC. Meanwhile, in the 5G communication system, an initial bandwidth part (BWP) for performing an initial access procedure may be set to the terminal, and the initial bandwidth part may be defined as the same frequency domain as the control region # 0. After the RRC connection, the UE may be notified of the bandwidth portion configuration information from the base station through the RRC signaling. The present invention proposes a terminal-specific RRC setting method for the control region # 0, and a method for setting the same control region as the control region # 0 to be monitored in different bandwidth parts. First, the same control area as the control area # 0 is set to the terminal-specific RRC. When specific fields are disabled for the control area set to the RRC, the control area is controlled to be the same as the control area # 0. You can think of it as a setting for an area. Alternatively, when the time / frequency region of the control region set to RRC is included in the time / frequency region of control region # 0, the control region set to RRC may be determined to be the same as the control region # 0. Next, a control area having a control area identifier of 0 is set in another bandwidth part. If the number of set bandwidth parts is less than 4, control area # 0 cannot be reset to RRC. If this is reset, the terminal may regard this as an error. If the set number of bandwidth portions is 4, the control region # 0 may be reset in another bandwidth portion through the terminal-specific RRC, and in this case, the terminal is the control region # 0 set in the RRC and the control region # 0 set in the MIB. You can override the setting.

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

As a representative example of the broadband wireless communication system, an LTE system employs an orthogonal frequency division multiplexing (OFDM) scheme in downlink (DL), and a single carrier frequency division multiple (SC-FDMA) in uplink (UL). Access) method is adopted. Uplink refers to a radio link through which a user equipment (UE) or mobile station (MS) transmits data or a control signal to a base station (eNode B or base station (BS)), and the downlink means a base station is a terminal. This refers to a wireless link that transmits data or control signals. In the multiple access scheme as described above, data or control information of each user is classified 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. do.

As a future communication system after LTE, that is, a 5G communication system should be able to freely reflect various requirements such as users and service providers, so that a service satisfying various requirements must be supported at the same time. 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 the data rate supported by LTE, LTE-A, or LTE-Pro. For example, in a 5G communication system, an eMBB should be able to provide a maximum data rate of 20 Gbps in downlink and a maximum data rate of 10 Gbps in uplink from a single base station. In addition, the 5G communication system should provide a maximum transmission rate and at the same time provide an increased user perceived data rate of the terminal. In order to meet these requirements, various transmission and reception technologies are required to be improved, including an improved multi-input multi-output (MIMO) transmission technology. 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 5G communication systems. In order to efficiently provide the Internet of Things, the mMTC requires large terminal access in a cell, improved terminal coverage, improved battery time, and reduced terminal cost. 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, the terminal supporting the mMTC is likely to be located in a shaded area that the cell does not cover, such as the basement of the building because of the nature of the service requires more coverage than other services provided by the 5G communication system. 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, very long battery life time (10-15 years) is required.

Finally, in the case of URLLC, it is a cellular-based wireless communication service used for a mission-critical purpose. 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 may be considered. Therefore, the communication provided by URLLC should provide very low latency and very high reliability. For example, a service that supports URLLC must satisfy air interface latency of less than 0.5 milliseconds, and at the same time 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. Is 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, the frame structure of the 5G system will be described in more detail with reference to the accompanying drawings.

FIG. 1 is a diagram illustrating a basic structure of a time-frequency region, which is a radio resource region in which data or a control channel is transmitted in a 5G system.

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

(E.g., 12) consecutive REs may constitute one resource block (RB, 104). One subframe 110 may consist of, for example, 14 OFDM symbols on the time axis (eg, when the subcarrier spacing is 15 KHz) and may correspond to a time of 1 ms.

2 illustrates a slot structure considered in a 5G system.

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

slot

202, 203 may be defined as 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 for subcarrier spacing. (204, 205). In the example of FIG. 2, a case where μ = 0 (204) and μ = 1 (205) are illustrated 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. In other words, the number of slots per one subframe according to the setting value μ for the subcarrier spacing (

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

) May vary. For each subcarrier spacing μ

And

Can be defined in Table 1 below.

TABLE 1

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

3 is a diagram illustrating an example of configuration of a bandwidth portion in a 5G communication system.

3 shows an example in which the terminal bandwidth 300 is set to two bandwidth parts, that is, bandwidth part # 1 301 and bandwidth part # 2 302. The base station may set one or a plurality of bandwidth parts to the terminal. And the base station can set the information in Table 2 below to the terminal for each bandwidth portion.

TABLE 2

In addition to the configuration information, various parameters related to the bandwidth portion may be set to the terminal. The information may be delivered to the terminal by the base station through higher layer signaling, for example, RRC signaling. At least one bandwidth portion among one or more configured bandwidth portions may be activated. Whether to activate the configured bandwidth portion may be delivered semi-statically from the base station through the RRC signaling or dynamically through the downlink control information (DCI).

The UE before the RRC connection may receive an initial bandwidth portion (Initial BWP) for the initial access from the base station through the MIB (Master Information Block). In more detail, the UE may transmit a PDCCH for receiving system information (remaining system information; RMSI or System Information Block 1; which may correspond to SIB1) required for initial access through the MIB in an initial access stage. Configuration information regarding a control resource set (CORESET) and a search space may be received. The control area and the search space set to the MIB may be regarded as an identifier (ID) 0, respectively. The base station may notify the terminal of setting information such as frequency allocation information, time allocation information, and numerology for the control region # 0 through the MIB. In addition, the base station may notify the terminal of 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 bandwidth portion for initial access. In this case, the identifier ID of the initial bandwidth portion may be regarded as zero.

The bandwidth portion supported by the 5G may be used for various purposes.

For example, when the bandwidth supported by the terminal is smaller than the system bandwidth, the bandwidth supported by the terminal may be supported by setting the bandwidth portion. For example, by setting the frequency location (eg, setting information 2 or locationAndBandwidth) of the bandwidth portion to the terminal in Table 2, the terminal can transmit and receive data at a specific frequency location within the system bandwidth.

As another example, the base station may set a plurality of bandwidth parts to the terminal for the purpose of supporting different neurology. For example, in order to support data transmission / reception using a subcarrier spacing of 15 kHz and a subcarrier spacing of 30 kHz to a user equipment, the base station may set two bandwidth portions to subcarrier spacing of 15 kHz and 30 kHz, respectively. Different bandwidth parts may be frequency division multiplexed, and when a user wants to transmit / receive data at a specific subcarrier interval, a bandwidth part set at a corresponding subcarrier interval may be activated.

As another example, for the purpose of reducing power consumption of the terminal, the base station may set a bandwidth portion 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, it may cause very large power consumption. In particular, it is very inefficient in terms of power consumption to monitor unnecessary downlink control channels with a large bandwidth of 100 MHz in the absence of traffic. In order to reduce power consumption of the terminal, the base station may set a bandwidth portion of a relatively small bandwidth, for example, a bandwidth portion of 20 MHz. In the absence of traffic, the terminal may perform a monitoring operation in the 20 MHz bandwidth portion, and when data is generated, may transmit and receive data in the bandwidth portion of 100 MHz according to the instruction of the base station.

In the method for setting the bandwidth portion, the terminals before the RRC connection (Connected) may receive the configuration information for the initial bandwidth portion (Initial Bandwidth Part) through the MIB (Master Information Block) in the initial connection step. In more detail, the terminal may include a control resource set for a downlink control channel through which downlink control information (DCI) for scheduling a system information block (SIB) may 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 bandwidth portion, and the terminal may receive a PDSCH through which the SIB is transmitted through the configured initial bandwidth portion. The initial bandwidth portion may be utilized for other system information (OSI), paging, and random access, in addition to receiving the SIB.

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

The SS / PBCH block refers to a physical layer channel block composed of a primary SS (PSS), a secondary SS (SSS), and a PBCH.

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

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

The terminal may detect the 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 monitor the control region # 0 assuming that the selected SS / PBCH block and the DMRS transmitted in the control region # 0 are quasi co located (QCL). The terminal may receive system information with downlink control information transmitted from the control region # 0. The UE may obtain configuration information related to a random access channel (RACH) required for initial access from the received system information. The UE may transmit a PRACH (Physical RACH) 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 that the terminal selected a certain block among the SS / PBCH blocks and monitor the control region # 0 associated with it.

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

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

The 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) is attached to the payload of the DCI message, and the CRC is scrambled with a Radio Network Temporary Identifier (RNTI) corresponding to the identity of the terminal. Different RNTIs are used according to the purpose of the DCI message, for example, UE-specific data transmission, power control command or random access response. That is, the RNTI is not explicitly transmitted but is included in the CRC calculation process. Upon receiving the DCI message transmitted on the PDCCH, the UE checks the CRC using the allocated RNTI and if the CRC check result is correct, the UE may know that the message is transmitted to the 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 (Random Access Response) 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. The DCI scheduling the 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. DCI format 0_0 with CRC scrambled with C-RNTI may include, for example, the information disclosed in Table 3 below.

TABLE 3

DCI format 0_1 may be used as a non-preparative DCI for scheduling a PUSCH, where the CRC may be scrambled with C-RNTI. DCI format 0_1 in which CRC is scrambled with C-RNTI may include, for example, information disclosed in Table 4 below.

TABLE 4

DCI format 1_0 may be used as a countermeasure DCI for scheduling PDSCH, where CRC may be scrambled with C-RNTI. DCI format 1_0 in which CRC is scrambled with C-RNTI may include, for example, information disclosed in Table 5 below.

TABLE 5

DCI format 1_1 may be used as a non-preparative DCI scheduling a PDSCH, where the CRC may be scrambled with C-RNTI. DCI format 1_1 in which CRC is scrambled with C-RNTI may include, for example, information disclosed in Table 6 below.

TABLE 6

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

4 is a diagram illustrating an example of a control region (Control Resource Set, CORESET) is transmitted in the downlink control channel in a 5G wireless communication system. 4 shows an example in which two control regions (control region # 1 401 and control region # 2 402) are set in the bandwidth portion 410 of the terminal on the frequency axis and one slot 420 on the time axis. Shows. The

control regions

401 and 402 may be set to specific frequency resources 403 within the entire terminal bandwidth portion 410 on the frequency axis. The time axis may be set to one or a plurality of OFDM symbols and may be defined as a control region set duration (404). In the example of FIG. 4, the control region # 1 401 is set to the length of two symbols of the control region, and the control region # 2 402 is set to the length of the control region of one symbol.

The control region in 5G described above may be configured by the base station through higher layer signaling (for example, system information, master information block (MIB), and radio resource control (RRC) signaling) to the terminal. Setting the control region to the terminal means providing information such as a control region identifier, a frequency position of the control region, and a symbol length of the control region. For example, the information disclosed in Table 7 may be included.

TABLE 7

In Table 7, tci-StatesPDCCH (simply named TCI state) configuration information includes one or more Synchronization Signal (SS) / PBCH (Physical Broadcast) in a QCL (Quasi Co Located) relationship with DMRS transmitted in a corresponding control region. It may include information of a channel block index or a channel state information reference signal (CSI-RS) index.

FIG. 5 is a diagram illustrating an example of basic units of time and frequency resources constituting a downlink control channel that can be used in 5G. Referring to FIG. 5, a basic unit of time and frequency resources constituting a control channel is named a Resource Element Group (REG) 503, and the REG 503 has one OFDM symbol 501 on the time axis and one PRB (on the frequency axis). Physical Resource Block 502), i.e., 12 subcarriers. 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. Referring to the REG 503 shown in FIG. 5 as an example, if the REG 503 may consist of 12 REs and the 1 CCE 504 consists of 6 REGs 503, the 1 CCE 504 It can be composed of 72 REs. When the downlink control region is set, the corresponding region may be composed of a plurality of CCEs 504, and a specific downlink control channel may be configured to one or more 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 the DCI, 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 1, 2, 4, 8, or 16 depending on the aggregation level (AL), and different CCEs may be used for link adaptation of the downlink control channel. Can be used to implement 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 has defined a search space indicating a set of CCEs for blind decoding. A search space is a set of downlink control channel candidates consisting of CCEs that a UE should attempt to decode on a given aggregation level, and various aggregations that make one bundle of 1, 2, 4, 8, and 16 CCEs. Since there is a level, the terminal has 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. A certain group of terminals or all terminals may examine a common search space of the PDCCH in order to receive cell common control information such as dynamic scheduling of paging information or a paging message. For example, PDSCH scheduling allocation information for transmission of SIB including cell information of a cell may be received by examining a common search space of a 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. Scheduling allocation information for the UE-specific PDSCH or PUSCH may be received 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 identity of the terminal 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). For example, the base station may include the number of PDCCH candidate groups at each aggregation level L, a monitoring period for the search space, a monitoring occasion in units of symbols in a slot for the search space, a search space type (common search space or a terminal-specific search space), and a corresponding search space. In the UE, a combination of DCI format and RNTI to be monitored and a control region index to monitor a search space may be set to the UE. For example, the information disclosed in Table 8 may be included.

TABLE 8

The base station may set one or a plurality of search space sets in the terminal according to the configuration information. For example, the base station may set the search space set 1 and the search space set 2 to the UE, and set the DCI format A scrambled with X-RNTI in the search space set 1 to be monitored in the common search space, and in the search space set 2 DCI format B scrambled with Y-RNTI may be configured to be monitored in the UE-specific search space.

According to the configuration information, 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 RNTIs specified above may follow the definitions and uses below.

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

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

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

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

P-RNTI (P-RNTI): For PDSCH scheduling, where paging is sent.

SI-RNTI (System Information RNTI): For 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): Purpose 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

The DCI formats specified above may follow the definition shown in Table 9 below.

TABLE 9

In 5G, as a plurality of search space sets may be set to different parameters (eg, parameters of Table 8), the set of search space sets monitored by the UE may vary at each time point. 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 in the terminal, the following conditions may be considered in the method of determining the search space set to be monitored by the terminal.

[Condition 1]

The number of PDCCH candidate groups that can be monitored per slot does not exceed X. The X value may vary depending on the subcarrier spacing, and may be defined, for example, in Table 10 below.

TABLE 10

In the above table, the subcarrier spacing may be defined as 15 · 2 ^μ kHz.

[Condition 2]

The number of CCEs constituting the total search space per slot (where the total search space means the total CCE set corresponding to the union region of the plurality of search space sets) does not exceed Y. The Y value may vary depending on the subcarrier spacing, and may be defined, for example, in Table 11 below.

TABLE 11

In the above table, the subcarrier spacing may be defined as 15 · 2 ^μ kHz.

For convenience of description, a situation that satisfies the

conditions

1 and 2 at a specific time point is defined as "condition A". Therefore, not satisfying condition A may mean not satisfying at least one of the

above conditions

1 and 2.

Depending on the setting of the search space sets of the base station, a case where the condition A described above is not satisfied may occur at a specific time point. If the condition A 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 the corresponding time point, and the base station may transmit the PDCCH to the selected search space set.

The following method may be followed as a method of selecting some search spaces from the entire set of search spaces.

If the condition A for the PDCCH is not satisfied at a specific time point (slot), the UE (or the base station) may search for the search space set in which the search space type is set to the common search space among the search space sets existing at the corresponding time point. -It can be selected in preference to a search space set set to a specific search space.

If all 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 the terminal-specific search space, a search space set having a low search space set index may have a higher priority. In consideration of priority, UE-specific search space sets may be selected within a range in which condition A is satisfied.

Next, explain the procedure for link recovery (also called Link Failure or Beam Failure Recovery (BFR)) of 5G communication systems.

6 is a diagram illustrating a connection recovery (BFR) procedure in a 5G communication system.

In step 601, the base station sets a periodic channel state information reference signal (CSI-RS) resource configuration index set for the purpose of detecting a link failure or a beam failure with higher layer signaling (eg, RRC signaling) to the terminal. q ₀ can be set. If the terminal is not provided with the configuration for q ₀ from the base station, the terminal is SS / PBCH block index or periodic CSI- indicated by the TCI states (corresponding to the TCI states of Table 7) set in the control areas The set q ₀ can be determined by the RS resource index. In step 602, the base station may set a threshold Q _out for the purpose of determining whether to fail the connection to the terminal by higher layer signaling (eg, RRC signaling). In step 603, the base station may configure a random access channel (RACH) resource for the purpose of transmitting a BFR request message to higher layer signaling (eg, RRC signaling) to the terminal. In step 604, the base station may configure a control area-BFR (CORESET-BFR) and a search space-BFR (SS-BFR) for receiving a PDCCH for a BFR response to higher layer signaling (eg, RRC signaling). At this time, the base station may be configured to monitor the DCI format scrambled with the C-RNTI as part of the configuration for the search space.

The UE may measure the connection quality in the CSI-RS resource (or SS / PBCH block) corresponding to the index in the q− ₀ set configured in step 601 (or determined by the TCI state of the control region). The terminal may compare the measured connection quality value with the threshold Q _out set in step 602. When the connection quality value in all the measurement resources set to q ₀ is not better than the threshold Q _out , the terminal may determine a link failure (Link Failure or Beam Failure).

If it is determined that the connection has failed, the terminal may transmit a BFR request message to one of the RACH resources configured in step 603 to the base station in step 605. If the terminal transmits the BFR request message to the base station in slot n, the terminal scrambled with C-RNTI based on the discovery space-BFR in the control region-BFR set in step 604 for a specific time from slot n + 4. Can be monitored.

When the base station receives the BFR request message from the terminal in step 605, the base station may transmit a BFR response message to the terminal (step 606). In this case, the base station may transmit the scrambled DCI to the control region-BFR and the search space-BFR configured in step 604 by the C-RNTI. The base station may newly activate the TCI states of the control regions set in the terminal through medium access control (MAC) Control Element (MAC) signaling to the terminal. Alternatively, the base station may notify the terminal of the reset of the control region by the RRC signaling.

When the UE is informed of the TCI reset or the control region reset of the control region by the BFR response message from the base station in step 606, the terminal may stop monitoring the control region-BFR and the search space-BFR set in step 604.

DETAILED DESCRIPTION Hereinafter, embodiments of the present invention will be described in detail with the accompanying drawings. Hereinafter, an embodiment of the present invention will be described using 5G as an example, but the embodiment of the present invention 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 invention may be applied to other communication systems through some modifications without departing from the scope of the present invention by the judgment of those skilled in the art.

In addition, in describing the present invention, when it is determined that a detailed description of a related function or configuration may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted. Terms to be described later are terms defined in consideration of functions in the present invention, and may be changed according to intentions or customs of users or operators. Therefore, the definition should be made based on the contents throughout the specification.

The first embodiment of the present invention proposes a control region and a search space monitoring method for a PDCCH reception by a UE in a process of restoring a connection after a connection failure occurs.

In the following, monitoring the control area may refer to a terminal operation for monitoring the control area and the search space set set in the control area.

FIG. 7 is a diagram illustrating an example of setting a control area for a connection recovery procedure and setting a resource for measurement for a connection failure detection purpose. In describing the following connection recovery procedure, reference may be made to the connection recovery procedure described with reference to FIG. 6.

First, an example of setting 720 of FIG. 7 will be described.

In the example of 720 of FIG. 7, the control region # 1 701 and the control region # 2 702 are set, and the TCI state corresponding to the TCI # 1 704 and the TCI # 2 705 is set. . In addition, a control region-BFR 703 is set for receiving a BFR response message after a connection failure occurs. The measurement resource q ₀ 706 is set for the purpose of connection failure detection, and the resource index set q ₀ 706 is a resource corresponding to the periodic CSI-RS # 1 707 and CSI-RS # 2 708. Contains an index. The terminal may measure resource regions corresponding to the CSI-RS # 1 707 and the CSI-RS # 2 708 for the purpose of detecting a connection failure. If it is determined that the connection quality of the CSI-RS # 1 707 and the CSI-RS # 2 708 are both smaller than the threshold Q _out , the terminal may transmit a BFR request message to the base station. After the UE transmits the BFR request message in slot n, the UE may monitor the preset control region-BFR 703 (and corresponding search space-BFR) in order to receive the BFR response message for a specific time from slot n + 4. .

In the example of 720, even when the terminal determines a connection failure (that is, the measurement quality of all the resources in the resource set q ₀ 706 is measured to be smaller than the threshold value), the terminal controls the control area # 1 (preset). 701, it is difficult to determine that the connection quality of the control region # 1 702, that is, the quality of the TCI # 1 704 and the TCI # 2 705, is also poor. This is between the CSI-RS # 1 707 and the CSI-RS # 2 708 in the resource set q- ₀ 706 and the TCI # 1 704 and TCI # 2 705 of the

control regions

704 and 705. This is because the UE does not know explicitly the correlation (or quasi co-located (QCL)). That is, according to some circumstances, even if the connection quality of all resources of the set resource set q- ₀ 706 is worse than the threshold value, the connection between the control area # 1 701 and the control area # 2 702 previously set The quality may be good enough to receive the PDCCH. Therefore, it is preferable that the terminal still monitors the other control region, the control region # 1 701 and the control region # 2 702 during the time of monitoring the control region-BFR 703 to recover the connection after detecting the connection failure. Can be.

First, an example of setting 730 of FIG. 7 will be described.

In the example of 730 of FIG. 7, the control region # 1 711 and the control region # 2 712 are set, and the TCI state corresponding to the TCI # 1 714 and the TCI # 2 715 is set. . In addition, a control region-BFR 713 is set for receiving a BFR response message after a connection failure occurs. In 730, it is assumed that a measurement resource q ₀ 716 for connection failure detection purpose is not set. Accordingly, the resource index set q ₀ 716 may be configured as a set of TCI states of each control region. That is, the set q ₀ 716 is a CSI-RS corresponding to TCI # 1 714 which is the TCI state of the control region # 1 711 and TCI # 2 715 which is the TCI state of the control region # 2 712. Or it may be configured in the same manner as the set of SS / PBCH index. For simplicity, in FIG. 7, the set q ₀ 716 is configured as an index set corresponding to TCI # 1 717 and TCI # 2 718. The terminal may measure resource regions corresponding to the TCI # 1 717 and the TCI # 2 718 for the purpose of detecting a connection failure. If it is determined that the connection quality of the TCI # 1 717 and the TCI # 2 708 are both smaller than the threshold Q _out , the terminal may transmit a BFR request message to the base station. After the UE transmits the BFR request message in slot n, the UE may monitor the preset control area-BFR 713 (and corresponding search space-BFR) to receive the BFR response message for a specific time from slot n + 4. .

In the example of 730, if the UE determines the connection failure (that is, the measurement quality of all the resources in the resource set q ₀ 716 is measured to be smaller than the threshold value), that is, control area # 1 (711), control area # The connection quality of 1 712, that is, the quality of TCI # 1 714 and TCI # 2 715 may also be poor. Therefore, while the terminal monitors the control region-BFR 713 for the restoration of the connection after detecting the connection failure, monitoring the other control regions (control region # 1 711 and control region # 2 712) rather than This may not be desirable because it corresponds to performing an unnecessary blind decoding operation for the UE.

For the above reason, whether or not the terminal continuously monitors the preset control regions that are being monitored before the connection failure is determined during the time interval during which the terminal monitors the control region-BFR, the configuration information of the base station; For example, the PDCCH monitoring operation of the terminal may vary depending on whether resource set q ₀ is set (or set content).

8 is a diagram illustrating a first embodiment of the present invention.

In step 801, the terminal may determine whether the base station receives configuration information on the resource set q ₀ for connection failure detection. If set q ₀ has been set, the UE can perform a “second PDCCH monitoring operation” in step 802. The second PDCCH monitoring operation may correspond to at least one of the following methods. If the set q ₀ is not set, the UE may perform a “first PDCCH monitoring operation” in step 803. The second PDCCH monitoring operation may be as follows.

For example, the first PDCCH monitoring operation and the second PDCCH monitoring operation may be as follows.

-During the time period for monitoring the control area-BFR, other monitoring areas (that is, the control areas that were monitored before the connection failure determination) are not monitored and only the monitoring of the control area-BFR is performed. Can be done.

<2nd PDCCH monitoring operation>

During the time interval for monitoring the control region-BFR, monitoring may be performed for other preset control regions (ie, control regions that were monitored before the connection failure determination).

As another example, the first PDCCH monitoring operation and the second PDCCH monitoring operation may be as follows.

-During the time zone for monitoring the control area-BFR, the control area where the search space type is set to the common search space among the other control areas that were previously set (ie, the control areas that were monitored before the connection failure determination) is monitored. can do.

<2nd PDCCH monitoring operation>

<2nd PDCCH monitoring operation>

In the first embodiment of the present invention, the monitoring operation for the PDCCH of the UE may be controlled differently according to the setting contents of the resource set q ₀ . For example, as a criterion for determining a control region to be additionally monitored during a time interval in which the UE monitors the control region-BFR, DMRS and the control region of the control region among the CSI-RS resources included in the resource set q ₀ configured for connection failure detection are determined. The presence or absence of QCL CSI-RS resources (or whether they correspond to the same CSI-RS resources as the RS indicated by TCI set in the same control region) may be considered.

9 is a diagram illustrating Embodiment 1-1 of the present invention.

In step 901, the terminal can determine whether the base station receives configuration information on the resource set q ₀ for connection failure detection.

If set q ₀ is set in step 901, the UE may determine whether the CSI-RS resource in QCL relation with DMRS of the control region exists in set q ₀ for the specific control region in step 902. If it is determined in step 902 that the CSI-RS resource having a QCL relationship with the DMRS of the control region exists in the set q ₀ , in step 903, the UE determines the corresponding control region determined in step 902 during the time interval for monitoring the control region-BFR. May not be monitored. If it is determined in step 902 that the CSI-RS resource in QCL relation with the DMRS of the control region does not exist in the set q ₀ , in step 904, the UE determines the corresponding control determined in step 902 during the time interval for monitoring the control region-BFR. You can monitor the area.

If the set q ₀ is not set, the terminal may monitor all other control areas that have been previously set during the time interval for monitoring the control area-BFR in step 905. Alternatively, the second PDCCH monitoring operation defined in the first embodiment may be performed.

The UE does not monitor the other control areas (that is, the control areas that were monitored before the connection failure determination) during the time interval for monitoring the control area-BFR, and always monitors the control area-BFR. Only monitoring can be performed.

During the time interval for monitoring the control region-BFR, the terminal selects a control region in which the search space type is set as the common search space among other preset control regions (that is, the control regions monitored before the connection failure determination). Can be monitored.

During the time interval for monitoring the control region-BFR, the terminal may also monitor other preset control regions (that is, control regions that were monitored before the connection failure determination).

Second Embodiment

If the UE monitors all or some of the other control areas (that is, the control areas monitored before the connection failure determination) during the time interval for monitoring the control area-BFR, a specific time point In this case, a case in which "condition A" described above is not satisfied may occur. In this case, in order to satisfy the condition A, the terminal may selectively monitor only a part of all the search space sets that are configured to be monitored (similarly, the base station may transmit the PDCCH to the selected part of the search space set).

[Method 1]

During the time interval during which the UE monitors the control region-BFR, when the terminal also monitors all or a portion of other preset control regions (that is, the control regions monitored before the connection failure determination), a specific time point ( If the condition A for the PDCCH is not satisfied in the slot (the slot 1) does not satisfy the condition of at least one of condition 1 or condition 2, that is, the number of candidate PDCCH candidates that can be monitored in a specific slot exceeds X in condition 1 Or at least one of the cases where the number of CCEs constituting the entire search space in a specific slot exceeds Y of condition 2), the UE and the base station may operate as follows.

The UE and the base station may select the search space set (that is, the search space-BFR) set in the control area-BFR among the search space sets to be monitored at the corresponding time point more preferentially than other search space sets. If condition A is satisfied even after the search space set set in the control region-BFR is satisfied, the terminal and the base station may further select the search space set set as the common search space. If condition A is satisfied even after selecting all the search spaces set as the common search space, the UE and the base station may further select the search space sets set as the UE-specific search space. In this case, when there are a plurality of search space sets configured as the 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-specific search space sets may be selected within a range in which the condition A is satisfied.

By the above method 1, the monitoring of the control region-BFR is prioritized, so that when a connection failure is detected, a recovery procedure can be performed more quickly.

[Method 2]

During the time interval during which the UE monitors the control region-BFR, when the terminal also monitors all or a portion of other preset control regions (that is, the control regions monitored before the connection failure determination), a specific time point ( If the condition A for the PDCCH is not satisfied in the slot), the UE and the base station may first select the search space set set as the common search space among the search space sets to be monitored at the corresponding time. If the condition A is satisfied even after selecting the search space set set as the common search space, the terminal and the base station set the search space set (that is, the search space-BFR) set in the control region-BFR as another terminal-specific search space. It can be selected in preference to a search space set. If condition A is satisfied even after the search space set set in the control region-BFR is satisfied, the terminal and the base station may further select the search space sets set as the terminal-specific search space. In this case, when there are a plurality of search space sets configured as the 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-specific search space sets may be selected within a range in which the condition A is satisfied.

Through the method 2, the monitoring of the common search space can be guaranteed as much as possible, so that various downlink control information that can be transmitted to the common search space can be received as much as possible. For example, communication with the base station can be continued using the DCI format scrambled with the C-RNTI transmitted to the common search space.

[Method 3]

During the time interval during which the UE monitors the control region-BFR, when the terminal also monitors all or a portion of other preset control regions (that is, the control regions monitored before the connection failure determination), a specific time point ( Slot) does not satisfy condition A for PDCCH,

The terminal and the base station may preferentially select a search space set having a search space type set as a common search space among search space sets to be monitored at a corresponding point of time, rather than a search space set configured as a terminal-specific search space. When all of the search space sets set as the common search space are selected (that is, when condition A is satisfied even after selecting all the search spaces set as the common search space), the terminal and the base station are configured as the search space set in the control region-BFR. The search space sets set to the terminal-specific search space may be selected including the set. 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 priority, UE-specific search space sets may be selected within a range in which condition A is satisfied.

Through the method 3, the monitoring of the common search space can be guaranteed as much as possible, so that various downlink control information that can be transmitted to the common search space can be received as much as possible. For example, communication with the base station can be continued using the DCI format scrambled with the C-RNTI transmitted to the common search space. In addition, the base station determines the priority of all UE-specific search spaces regardless of whether the search space set is set in the control region-BFR (that is, the search space set index is assigned according to the desired priority). Increased flexibility

Third Embodiment

10 is a diagram illustrating an example of bandwidth configuration.

The terminal may receive the initial bandwidth portion 1000 through the MIB from the base station. As described above, the initial bandwidth portion may correspond to the same frequency axis band as the control region # 0 1002 set in the MIB. The UE may further receive a bandwidth portion (eg, bandwidth portion # 1 1001 of FIG. 10) through UE-specific RRC signaling. In addition, the UE may additionally set a control region to be monitored in the corresponding bandwidth portion through UE-specific RRC signaling (eg, corresponding to control region # 1 of FIG. 10).

In the example of FIG. 10, the bandwidth portion # 1 1001 is set to include the initial bandwidth portion 1000. At this time, if the base station allows the terminal to monitor the control area # 0 (1002) (or the control area having the same settings as the control area # 0 (1002)) in the bandwidth portion # 1 (1001), the control area # 0 (1002) (or a control area having the same setting as the control area # 0 1002) should be able to be set as the control area of the bandwidth part # 1 1001. However, depending on the situation, it may be impossible to set the same control area as the control area set in the MIB to the terminal-specific RRC.

FIG. 11 is a diagram illustrating an example of a situation in which the same control region as the control region configured in the MIB cannot be set as the terminal-specific RRC. In FIG. 11, control region # 0 1101 indicates a control region set to MIB, and control region # 1 1102 indicates a control region set to terminal-specific RRC. According to FIG. 11, the control region # 0 1101 set to MIB may be set to 1-RB unit 1104 in frequency axis allocation, while the control region # 1 1102 is set to terminal-specific RRC. May be set in 6-RB units 1103. Therefore, in the example shown in FIG. 11, since the control region # 0 1101 set to MIB is allocated from the fifth RB, the control region # 1 1102 having the same frequency axis assignment is set to the terminal-specific RRC. It is impossible to do.

In order to solve the above problem, the second embodiment of the present invention proposes a method of setting the same control area as that of the MIB through UE-specific RRC signaling.

Before describing the embodiment, control region parameters that can be set by RRC signaling are described again (see Table 7 above).

TABLE 12

If the bandwidth portion (named bandwidth portion # 1) set to UE-specific RRC is configured to include the initial bandwidth portion (named bandwidth portion # 0), the bandwidth portion # 1 to MIB is set as follows. The control area, that is, the control area # 0 (or the control area having the same setting as the control area # 0 1002) can be set to monitor.

[Method 1]

The base station may set the control region to be monitored in the bandwidth portion # 1 to the terminal to the terminal-specific RRC. At this time, in order to set the control area having the same setting as the control area set to the MIB (that is, the control area # 0), the base station may set the control area to the terminal through RRC signaling. In this case, the base station may notify the terminal of only the control region identifier among the parameters of Table 12. If the terminal is notified of only the control region identifier among the control region configuration parameters by the RRC signaling from the base station, the terminal is referred to as a control region having the same configuration as the control region (ie, control region # 0) set in the MIB. Can be considered. Therefore, the terminal may monitor the control region having the same configuration as the control region # 0 in the bandwidth portion # 1.

[Method 2]

The base station may set the control region to be monitored in the bandwidth portion # 1 to the terminal to the terminal-specific RRC. At this time, in order to set the control area having the same setting as the control area set to the MIB (that is, the control area # 0), the base station may set the control area to the terminal through RRC signaling. In this case, the base station may not notify the terminal of only the frequency axis allocation information among the parameters of Table 12. If the terminal is not informed of the frequency axis resource allocation information among the control region configuration parameters by the RRC signaling from the base station, the terminal sets the same control region as the control region (ie, control region # 0) set in the MIB (the same configuration). Can be regarded as a control region with frequency axis allocation information). Therefore, the terminal may monitor the control region having the same configuration as the control region # 0 in the bandwidth portion # 1.

At this time, all of the remaining parameters except the frequency axis resource allocation information set to RRC may be set to be the same as the setting of the control region # 0 set to MIB. If a parameter other than the configuration of the control region # 0 is received, the terminal may determine the corresponding RRC configuration as an error.

Alternatively, the parameters other than the frequency axis resource allocation information and the TCI state setting information among the parameters set by the RRC may be set to be identical to the setting of the control region # 0 set as the MIB. If a parameter different from the configuration of the control region # 0 is received for the remaining parameters, the terminal may determine the corresponding RRC configuration as an error. In addition, the TCI state may be set to a set of reference signals (SS / PBCH block index or CSI-RS resource index) including an SS / PBCH block index associated with control region # 0 set to MIB.

[Method 3]

The base station may set the control region to be monitored in the bandwidth portion # 1 to the terminal to the terminal-specific RRC. At this time, in order to set the control area having the same setting as the control area (i.e., control area # 0) set as MIB, the base station sets the control area by the RRC signaling to the terminal. Only the terminal may not be notified. If the terminal is not informed of the frequency axis resource allocation information among the control region configuration parameters by the RRC signaling from the base station, the terminal sets the same control region as the control region (ie, control region # 0) set in the MIB (the same configuration). Can be regarded as a control region with frequency axis allocation information). Therefore, the terminal may monitor the control region having the same configuration as the control region # 0 in the bandwidth portion # 1.

[Method 4]

The base station may set the control region to be monitored in the bandwidth portion # 1 to the terminal to the terminal-specific RRC. At this time, in order to set the control area having the same setting as the control area (i.e., control area # 0) set as MIB, the base station sets the control area by the RRC signaling to the terminal. You can indicate to a particular state not used. Frequency axis allocation information for the control region may be notified to the terminal as a bitmap having a 45-bit size as follows.

frequencyDomainResources BIT STRING (SIZE (45)),

The base station may indicate all of the frequency axis allocation information to the terminal as '0' (that is, '0000 쪋 0').

If the terminal instructs all of the frequency axis resource allocation information as '0' among the control region configuration parameters by the RRC signaling from the base station, the terminal designates the corresponding control region set in the MIB (that is, the control region # 0). It can be regarded as a control area with the same setting (same frequency axis allocation information). Therefore, the terminal may monitor the control region having the same configuration as the control region # 0 in the bandwidth portion # 1.

Fourth Embodiment

In setting the control area in each bandwidth part, the base station cannot set the control area having the same identifier (ID) in different bandwidth parts. In the meantime, the terminal receives a control area having an ID of 0, that is, control area # 0, from the MIB in the initial access step. Therefore, a restriction may be generated in setting a control region having an ID of 0 in another bandwidth portion which is configured as a terminal-specific RRC instead of the initial bandwidth portion. The fourth embodiment of the present invention proposes a method of setting a control region having a control region ID of 0 as a terminal-specific RRC and replacing the control region # 0 set to the MIB.

Before describing an embodiment of the present invention, the setting of the bandwidth portion of 5G will be described in more detail.

12 is a diagram illustrating an example of bandwidth configuration.

The UE may be configured with up to four bandwidth parts by higher layer signaling, eg, UE-specific RRC signaling, from the base station. The number of bits of the bandwidth portion indicator (refer to [Table 4] and [Table 6]) of the DCI may be determined by the set number of bandwidth portions. In this case, the interpretation of the bandwidth indicator field may vary according to the number of bandwidth portions set to UE-specific RRC. If the number of bandwidth parts set to UE-specific RRC is less than four, the initial bandwidth part set to MIB may be automatically included as a bandwidth part which may be indicated by the bandwidth part indicator, and bits of '0' or '00' This may correspond to a field indicator (ie, equal to a bandwidth part ID of 0). That is, when the number of bandwidth portions set to UE-specific RRC is smaller than four, the initial bandwidth portion may be interpreted in the same manner as regarded as one of the set bandwidth portions. If the number of bandwidth parts set to UE-specific RRC is four, each of the four bandwidth parts set to RRC may correspond to a bit field of a bandwidth part indicator corresponding to 2 bits.

12 illustrates an example in which three

bandwidth parts

1201, 1202, and 1203 are configured as UE-specific RRCs. In this case, the terminal may assume that a total of four bandwidth parts including the initial bandwidth part 1200 are set, and may correspond to two-bit bandwidth part indicators, respectively. As shown in 1220 of FIG. 12, the initial bandwidth portion 1200 is '00', the bandwidth portion # 1 1201 is '01', the bandwidth portion # 2 1202 is '10', and the bandwidth portion # 3 1203 is Each may correspond to '11'.

12 illustrates an example in which 4

bandwidth parts

1205, 1206, 1207, and 1208 are set as UE-specific RRCs. In this case, the terminal may consider that a total of four bandwidth parts except for the initial bandwidth part 1200 is set, and may correspond to two-bit bandwidth part indicators, respectively. As in 1230 of FIG. 12, the bandwidth portion # 0 1205 is '00', the bandwidth portion # 1 1206 is '01', the bandwidth portion # 2 1207 is '10', and the bandwidth portion # 3 1208. May correspond to '11', respectively.

As described above, when the number of bandwidth portions set from the base station to the UE-specific RRC is less than 4, the terminal may regard the bandwidth portion set from the MIB as one of the automatically set bandwidth portions. At this time, since the initial bandwidth portion always includes the control region set from the MIB and the control region # 0 (the control region having the identifier ID 0), the terminal automatically includes the control region # 0 in setting the control region. . Therefore, it is impossible for the base station to set a control region having an identifier of 0 in another bandwidth part set to UE-specific RRC.

13 is a view showing a fourth embodiment of the present invention.

The UE may determine whether the number n _{BWP and RRC} of the bandwidth portion set to UE-specific RRC in step 1301 is greater than three. If n _{BWP and RRC} are greater than 3 in step 1301 _{, the UE} may receive a control region having an ID of 0 from the base station as UE-specific RRC in step 1302. When the control area with ID 0 is set, control area # 0 set to MIB is ignored and can be replaced with control area # 0 set to terminal-specific RRC. If n _{BWP, RRC} = 4 is less than or equal to 3 in step 1301 _{, the UE} cannot receive a control area of ID 0 from the base station as a UE-specific RRC in step 1303. If set, this can be considered an error.

The base station can always set the control region to another identifier except the identifier 0 in setting the control region in each bandwidth portion. The terminal does not expect that the control region whose identifier is 0 is set in the bandwidth portion set to the terminal-specific RRC.

If the terminal has received four bandwidth parts from the base station to the UE-specific RRC, and at least one bandwidth part is set to include the initial bandwidth part, it can follow the operation below.

If there is only one bandwidth portion (named bandwidth portion # 1) configured to include the initial bandwidth portion, the terminal may monitor the control region # 0 set to MIB in the bandwidth portion # 1. That is, the terminal may regard the control region # 0 as one of the control regions set in the bandwidth portion # 1. The base station may transmit the PDCCH through the control region # 0 when the bandwidth portion # 1 of the terminal is activated.

If there is only one bandwidth portion configured to include the initial bandwidth portion, the terminal selects the control region # 0 set as MIB in the bandwidth portion having the lowest (or higher) bandwidth portion index among the bandwidth portions including the initial bandwidth portion. Can be monitored. The base station may transmit the PDCCH through the control region # 0 when the bandwidth portion having the lowest (or the highest) bandwidth portion index among the bandwidth portions including the initial bandwidth portion among the bandwidth portions set for the terminal is activated. .

In order to perform the above embodiments of the present invention, a transmitter, a receiver, and a controller of the terminal and the base station are illustrated in FIGS. 14 and 15, respectively. A method of transmitting and receiving 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 according to the above embodiment is shown. Each part must operate according to the embodiment.

In detail, FIG. 14 is a block diagram illustrating an internal structure of a terminal according to an exemplary embodiment of the present invention. As shown in FIG. 14, the terminal of the present invention may include a terminal processor 1401, a receiver 1402, and a transmitter 1403.

The terminal processor 1401 may control a series of processes in which a terminal may operate according to the above-described embodiment of the present invention. For example, the monitoring method for the PDCCH and the method for reinterpreting the setting of the control region according to an embodiment of the present invention can be controlled differently. The terminal processor 1401 may be referred to as a controller or a controller and may include at least one processor. The terminal processing unit 1401 receives first information on the number of PDCCH candidates and second information on the number of control channel elements (CCEs) from the base station. Transmit a beam failure recovery (BFR) request message to the base station in a slot, select a search area set of a first control area and a search area set of a second control area related to the BFR in a second slot, and select the selected second control The control information for receiving the BFR response message may be controlled to be monitored in the discovery region set of the region. In addition, the terminal processing unit 101 may determine that information about the PDCCH of the first control region and the second control region in the second slot is one of a first condition according to the first information or a second condition according to the second information. If at least one is not satisfied, it is possible to control to select the search region set of the second control region first. In addition, the terminal processor 1401 may select a search area set of the second control area and then control to select a search space set in which the search space type is set as a common search space in the first control area. In addition, the terminal processing unit 1401 selects a search space set in which the search space type is set as a common search space, and then a search space having a low search space index among the search space sets in which the search space type is set as a terminal-specific search space. Can be controlled to select first. The information on the PDCCH includes the number of PDCCH candidates and the number of CCEs set in the first control region and the second control region, and the first condition is that the number of candidate PDCCH candidates is equal to or less than the number of PDCCHs according to the first information. The second condition includes that the set number of CCEs is equal to or less than the number of CCEs according to the second information.

The terminal receiver 1402 and the terminal may collectively be referred to as a transceiver in the embodiment of the present invention. The transceiver may transmit and receive a signal with the base station. The signal may include control information and data. To this end, the transceiver 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. Also, the transceiver may receive a signal through a wireless channel, output the signal to the terminal processor 1401, and transmit a signal output from the terminal processor 1401 through a wireless channel.

15 is a block diagram illustrating an internal structure of a base station according to an embodiment of the present invention. As shown in FIG. 15, the base station of the present invention may include a base station processor 1501, a receiver 1502, and a transmitter 1503.

The base station processor 1501 may control a series of processes to operate the base station according to the above-described embodiment of the present invention. For example, the PDCCH transmission method and the control region setting method according to the embodiment of the present invention can be controlled differently. The base station processor 1501 may be referred to as a controller or a controller and may include at least one processor.

The base station processor 1501 transmits first information on the number of physical downlink control channel (PDCCH) candidates and second information on the number of control channel elements (CCEs) to the terminal, and transmits the BFR from the terminal to the base station in a first slot. receiving a beam failure recovery request message, selecting a search area set of a first control area and a search area set of a second control area related to a BFR in a second slot, and selecting a search area set of the selected second control area The resource may be controlled to transmit control information for receiving a BFR response message.

In addition, the base station processor 1501 may determine that information about the PDCCH of the first control region and the second control region in the second slot is a first condition according to the first information or a second condition according to the second information. If at least one is not satisfied, it is possible to control to select the search region set of the second control region first. In addition, the base station processor 1501 may select a search area set of the second control area and then control to select a search space set in which the search space type is set as a common search space in the first control area. In addition, the base station processor 1501 selects a search space set in which the search space type is set as a common search space, and then searches for a search space having a low search space index among the search space sets in which the search space type is set to a terminal-specific search space. Can be controlled to select first. The information on the PDCCH includes the number of PDCCH candidates and the number of CCEs set in the first control region and the second control region, and the first condition is that the number of candidate PDCCH candidates is equal to or less than the number of PDCCHs according to the first information. The second condition includes that the set number of CCEs is equal to or less than the number of CCEs according to the second information.

The base station receiver 1502 and the base station transmitter 1503 may be collectively referred to as a transceiver in the embodiment of the present invention. The transceiver may transmit and receive a signal with the terminal. The signal may include control information and data. To this end, the transceiver 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. Also, the transceiver may receive a signal through a wireless channel, output the signal to the base station processor 1501, and transmit a signal output from the base station processor 1501 through a wireless channel.

On the other hand, the embodiments of the present invention disclosed in the specification and drawings are merely presented specific examples to easily explain the technical contents of the present invention and help the understanding of the present invention, and are not intended to limit the scope of the present invention. That is, it will be apparent to those skilled in the art that other modifications based on the technical idea of the present invention can be implemented. In addition, each of the above embodiments can be combined with each other if necessary to operate.

Claims

In the operation method of the terminal,

Receiving first information on the number of physical downlink control channel (PDCCH) candidates and second information on the number of control channel elements (CCEs) from the base station;

If a connection failure occurs, transmitting a beam failure recovery (BFR) request message to the base station in the first slot to the base station;

Selecting a search region set of the first control region and a search region set of the second control region associated with the BFR in the second slot; And

Monitoring control information for receiving a BFR response message in the search region set of the selected second control region,

If the information about the PDCCH of the first control region and the second control region in the second slot does not satisfy at least one of the first condition according to the first information or the second condition according to the second information, the And selecting a search area set of the second control area first.
The method of claim 1,

And selecting a search space set in which the search space type is set to a common search space in the first control region after selecting the search region set of the second control region.
The method of claim 2, wherein after selecting a search space set in which the search space type is set as a common search space, a search space having a low search space index is given priority among the search space sets in which the search space type is set as a terminal-specific search space. Selecting.
The method of claim 1,

The information on the PDCCH includes the number of PDCCH candidates and the number of CCEs set in the first control region and the second control region.

Wherein the first condition is that the set number of PDCCH candidates is less than or equal to the number of PDCCHs according to the first information, and the second condition is that the number of set CCEs is less than or equal to the number of CCEs according to the second information.
In the terminal,

A transceiver; And

It is connected to the transceiver and receives first information on the number of physical downlink control channel (PDCCH) candidates and second information on the number of control channel elements (CCEs) from the base station. Send a beam failure recovery (BFR) request message to the base station in slot 1, select a search range set of the first control region and a search region set of the second control region related to the BFR in the second slot, and select the selected second A control unit for controlling to monitor control information for receiving a BFR response message in the search region set of the control region,

If the information about the PDCCH of the first control region and the second control region in the second slot does not satisfy at least one of the first condition according to the first information or the second condition according to the second information, the And selecting the search area set of the second control area first.
The method of claim 5,

And selecting a search space set in which a search space type is set as a common search space in the first control region after selecting the search region set of the second control region.
The method of claim 6, wherein after selecting a search space set in which the search space type is set as a common search space, a search space having a low search space index is given priority among the search space sets in which the search space type is set as a terminal-specific search space. Selecting a terminal.
The method of claim 5,

The information on the PDCCH includes the number of PDCCH candidates and the number of CCEs set in the first control region and the second control region.

The first condition is that the number of candidate PDCCH candidates is less than or equal to the number of PDCCHs according to the first information, and the second condition is that the number of the set CCEs is less than or equal to the number of CCEs according to the second information.
In the operation method of the base station,

Transmitting first information on the number of physical downlink control channel (PDCCH) candidates and second information on the number of control channel elements (CCEs) to the UE;

Receiving a beam failure recovery (BFR) request message from the terminal to the base station in a first slot;

Selecting a search region set of the first control region and a search region set of the second control region associated with the BFR in the second slot; And

Transmitting control information for receiving a BFR response message in a resource of a search region set of the selected second control region,

If the information about the PDCCH of the first control region and the second control region in the second slot does not satisfy at least one of the first condition according to the first information or the second condition according to the second information, the And selecting a search area set of the second control area first.
The method of claim 9,

And selecting a search space set in which the search space type is set to a common search space in the first control region after selecting the search region set of the second control region.
The method of claim 10, wherein after selecting a search space set in which the search space type is set as a common search space, a search space having a low search space index is given priority among the search space sets in which the search space type is set as a terminal-specific search space. Selecting.
The method of claim 9,

The information on the PDCCH includes the number of PDCCH candidates and the number of CCEs set in the first control region and the second control region.

Wherein the first condition is that the set number of PDCCH candidates is less than or equal to the number of PDCCHs according to the first information, and the second condition is that the number of set CCEs is less than or equal to the number of CCEs according to the second information.
In the base station,

A transceiver; And

It is connected to the transceiver, and transmits the first information on the number of physical downlink control channel (PDCCH) candidate and the second information on the number of control channel element (CCE) to the terminal, the BFR from the terminal to the base station in the first slot receive a beam failure recovery request message, select a search region set of a first control region and a search region set of a second control region related to the BFR in a second slot, and select a search region set of the selected second control region A control unit for controlling to transmit control information for receiving a BFR response message from a resource,

If the information about the PDCCH of the first control region and the second control region in the second slot does not satisfy at least one of the first condition according to the first information or the second condition according to the second information, the And bases on selecting a search area set of the second control area.
The method of claim 13,

After selecting the search region set of the second control region, select a search space set in which the search space type is set to a common search space in the first control region,

Selecting a search space set in which the search space type is set as a common search space, and then selecting a search space having a low search space index among the search space sets in which the search space type is set to a terminal-specific search space; Base station.
The method of claim 13,

The information on the PDCCH includes the number of PDCCH candidates and the number of CCEs set in the first control region and the second control region.

Wherein the first condition is that the set number of PDCCH candidates is less than or equal to the number of PDCCHs according to the first information, and the second condition is that the number of set CCEs is less than or equal to the number of CCEs according to the second information.