Method and device for transmitting and receiving downlink control channel

Abstract

A method for receiving a physical downlink control channel (PDCCH) by a user equipment (UE) through a search space (SS) set in a wireless communication system is disclosed. The method includes sending first information related to the number of X time slots and second information related to the number of at least one Y time slot, and receiving the PDCCH through a UE-specific SS (USS) set in at least one Y time slot based on the first information and the second information. At least one Y time slot is included in the X time slot, and X and Y are positive integers.

Description

Technical Field

[0001] The present disclosure relates to a method and apparatus for transmitting and receiving a downlink control channel, and more particularly, to a method and apparatus for configuring a physical downlink control channel (PDCCH) monitoring duration, so as to reduce power consumption of a user equipment in monitoring the PDCCH. Background Art

[0002] As more and more communication devices require greater communication services in line with the current trend, the next-generation fifth-generation (5G) system is needed to provide enhanced wireless broadband communication compared to the traditional LTE system. In the next-generation 5G system, communication scenarios are divided into enhanced mobile broadband (eMBB), ultra-reliable and low-latency communication (URLLC), massive machine type communication (mMTC), etc.

[0003] In this article, eMBB is a next-generation mobile communication scenario characterized by high spectral efficiency, high user experience data rate, and peak data rate, URLLC is a next-generation mobile communication scenario characterized by ultra-high reliability, ultra-low latency, and ultra-high availability (e.g., vehicle-to-everything (V2X), emergency services, and remote control), and mMTC is a next-generation mobile communication scenario characterized by low cost, low energy, short packets, and massive connections (e.g., the Internet of Things (IoT)). Summary of the invention

[0004] Technical issues

[0005] An object of the present disclosure is to provide a method for transmitting and receiving a downlink control channel and an apparatus thereof.

[0006] Those skilled in the art will understand that the objectives that can be achieved by the present disclosure are not limited to what has been specifically described above, and the above and other objectives that can be achieved by the present disclosure can be clearly understood from the following detailed description.

[0007] Technical Solution

[0008] According to one aspect of the present disclosure, a method for receiving a physical downlink control channel (PDCCH) by a user equipment (UE) through a search space (SS) set in a wireless communication system is provided, including: transmitting first information related to the number of X time slots and second information related to the number of at least one Y time slot, and receiving a first PDCCH through a UE-specific SS (USS) set in at least one Y time slot based on the first information and the second information. The at least one Y time slot may be included in the X time slot, and X and Y may be positive integers.

[0009] The second PDCCH may be received through a common SS (CSS) set within X slots.

[0010] The set of CSSs to be monitored in the Y time slot may be determined to have a higher priority than the set of USSs to be monitored in the Y time slot.

[0011] The first information and the second information may be transmitted through capability information represented as (X, Y) which is a combination of the number of X time slots and the number of at least one Y time slot.

[0012] The X time slots may be consecutive, and at least one Y time slot may be consecutive.

[0013] The start time slot of at least one Y time slot may not be aligned with the start time slot of the X time slot.

[0014] In another aspect of the present invention, a user equipment (UE) is provided herein, which is used to receive a physical downlink control channel (PDCCH) through a search space (SS) set in a wireless communication system, and the user equipment includes at least one transceiver; at least one processor; and at least one memory, the at least one memory being operably connected to the at least one processor and configured to store instructions, which when executed, cause the at least one processor to perform operations. The operations include: sending first information related to the number of X time slots and second information related to the number of at least one Y time slot through at least one transceiver, and receiving a first PDCCH through a UE-specific SS (USS) set in at least one Y time slot based on the first information and the second information through at least one transceiver. At least one Y time slot may be included in the X time slot, and X and Y may be positive integers.

[0015] The second PDCCH may be received through a common SS (CSS) set within X slots.

[0016] The set of CSSs to be monitored in the Y time slot may be determined to have a higher priority than the set of USSs to be monitored in the Y time slot.

[0017] The first information and the second information may be transmitted through capability information represented as (X, Y) which is a combination of the number of X time slots and the number of at least one Y time slot.

[0018] The X time slots may be consecutive, and at least one Y time slot may be consecutive.

[0019] The start time slot of at least one Y time slot may not be aligned with the start time slot of the X time slot.

[0020] In another aspect of the present disclosure, a device for receiving a physical downlink control channel (PDCCH) through a search space (SS) set in a wireless communication system is provided herein, comprising: at least one processor; at least one memory, the at least one memory being operably connected to the at least one processor and configured to store instructions, the instructions causing the at least one processor to perform operations when executed. The operations include sending first information related to the number of X time slots and second information related to the number of at least one Y time slot, and receiving PDCCH through a UE-specific SS (USS) set within at least one Y time slot based on the first information and the second information. At least one Y time slot may be included in the X time slot, and X and Y may be positive integers.

[0021] In another aspect of the present disclosure, a computer-readable storage medium is provided herein, including at least one computer program, the at least one computer program causing at least one processor to perform operations. The operations include: sending first information related to the number of X time slots and second information related to the number of at least one Y time slot; and receiving a physical downlink control channel (PDCCH) through a UE-specific search space (USS) set within at least one Y time slot based on the first information and the second information. At least one Y time slot may be included in the X time slot, and X and Y may be positive integers.

[0022] In another aspect of the present disclosure, a method for transmitting a physical downlink control channel (PDCCH) through a search space (SS) set by a base station (BS) in a wireless communication system is provided herein, comprising: receiving first information related to the number of X time slots and second information related to the number of at least one Y time slot; and transmitting the PDCCH through a UE-specific SS (USS) set within at least one Y time slot based on the first information and the second information. The at least one Y time slot may be included in the X time slot, and X and Y may be positive integers.

[0023] In another aspect of the present disclosure, a base station (BS) is provided herein for transmitting a physical downlink control channel (PDCCH) through a search space (SS) set in a wireless communication system, the base station comprising at least one transceiver; at least one processor; and at least one memory, the at least one memory being operably connected to the at least one processor and configured to store instructions, the instructions causing the at least one processor to perform operations when executed. The operations include: receiving first information related to the number of X time slots and second information related to the number of at least one Y time slot through at least one transceiver; and transmitting PDCCH through a UE-specific SS (USS) set within at least one Y time slot through at least one transceiver based on the first information and the second information. At least one Y time slot may be included in the X time slot, and X and Y may be positive integers.

[0024] Beneficial Effects

[0025] According to the present disclosure, the number of blind decodings can be reduced by extending the PDCCH monitoring gap of the UE.

[0026] As a result, the UE can achieve power saving and reduce the load of performing blind decoding multiple times in a short period of time.

[0027] Those skilled in the art will recognize that the effects that can be achieved using the present disclosure are not limited to the contents that have been specifically described above, and other advantages of the present disclosure will be more clearly understood from the following detailed description in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 illustrates physical channels in a 3rd Generation Partnership Project (3GPP) system as an exemplary wireless communication system and a general signal transmission method using the same;

[0029] Figure 2 illustrates the radio frame structure;

[0030] Figure 3 illustrating a resource grid during the duration of a time slot;

[0031] Figure 4 illustrates an exemplary mapping of physical channels in time slots;

[0032] Figure 5 Figure 1 shows the transmission process of the physical channel;

[0033] Figure 6 , Figure 7 , Figure 8 is a diagram illustrating a physical downlink control channel (PDCCH) in an NR system;

[0034] Fig. 9is a diagram for explaining an overall operation process of a UE and a BS according to an embodiment of the present disclosure;

[0035] Fig.10 and Fig.11 is a diagram for explaining a PDCCH monitoring gap according to an embodiment of the present disclosure;

[0036] Fig.12 An exemplary communication system applicable to the present disclosure is illustrated;

[0037] Fig.13 illustrates an exemplary wireless device suitable for use with the present disclosure; and

[0038] Fig.14 An exemplary vehicle or autonomous vehicle suitable for use with the present disclosure is shown. DETAILED DESCRIPTION

[0039] The following technology can be used in various wireless access systems, such as code division multiple access (CDMA), frequency division multiple access (FDMA), time division multiple access (TDMA), orthogonal frequency division multiple access (OFDMA), single carrier frequency division multiple access (SC-FDMA), etc. CDMA can be implemented as a radio technology such as Universal Terrestrial Radio Access (UTRA) or CDMA2000. TDMA can be implemented as a radio technology such as Global System for Mobile Communications (GSM) / General Packet Radio Service (GPRS) / Enhanced Data Rates for GSM Evolution (EDGE). OFDMA can be implemented as a radio technology such as Institute of Electrical and Electronics Engineers (IEEE) 802.11 (Wireless Fidelity (Wi-Fi)), IEEE 802.16 (Worldwide Interoperability for Microwave Access (WiMAX)), IEEE 802.20, Evolved UTRA (E-UTRA), etc. UTRA is part of Universal Mobile Telecommunications System (UMTS). 3rd Generation Partnership Project (3GPP) Long Term Evolution (LTE) is a part of Evolved UMTS (E-UMTS) using E-UTRA, and LTE Advanced (LTE-A) is an evolution of 3GPP LTE. 3GPP New Radio or New Radio Access Technology (NR) is an evolved version of 3GPP LTE / LTE-A.

[0040] Although the following description is given in the context of a 3GPP communication system (e.g., NR) for clarity, the technical spirit of the present disclosure is not limited to the 3GPP communication system. For background technology, the terms and abbreviations used in the present disclosure refer to technical specifications (e.g., 38.211, 38.212, 38.213, 38.214, 38.300, 38.331, etc.) published before the present disclosure.

[0041] 5G communication involving a new radio access technology (NR) system will be described below.

[0042] The three key requirement areas for 5G are (1) enhanced mobile broadband (eMBB), (2) massive machine-type communications (mMTC), and (3) ultra-reliable and low-latency communications (URLLC).

[0043] Some use cases may require optimization in multiple dimensions, while others may focus on just one key performance indicator (KPI). 5G supports this variety of use cases in a flexible and reliable manner.

[0044] eMBB goes far beyond basic mobile Internet access and covers rich interactive work, media and entertainment applications in the cloud or augmented reality (AR). Data is one of the key drivers of 5G, and in the 5G era, we may see no dedicated voice services for the first time. In 5G, it is expected that voice is simply processed as an application using the data connection provided by the communication system. The main driving force for the increased traffic is the increase in content size and the number of applications that require high data rates. As more devices are connected to the Internet, streaming services (audio and video), interactive video, and mobile Internet connections will continue to be more widely used. Many of these applications require always-on connections to push real-time information and notifications to users. Cloud storage and applications for mobile communication platforms are increasing rapidly. This applies to both work and entertainment. Cloud storage is a specific use case that drives the growth of uplink data rates. 5G will also be used for remote work in the cloud, which requires much lower end-to-end latency when done using a tactile interface in order to maintain a good user experience. Entertainment (e.g., cloud gaming and video streaming) is another key driver for increased demand for mobile broadband capacity. Entertainment is very important on smartphones and tablets anywhere, including high mobility environments such as trains, cars and airplanes. Another use case is AR and information search for entertainment, which requires very low latency and large amounts of real-time data.

[0045] One of the most anticipated 5G use cases is the ability to actively connect embedded sensors in every field, i.e. mMTC. It is expected that there will be 20.4 billion potential Internet of Things (IoT) devices by 2020. In industrial IoT, 5G is one of the areas that will play a key role in enabling smart cities, asset tracking, smart utilities, agriculture, and secure infrastructure.

[0046] URLLC includes services that will transform industries utilizing ultra-reliable / available low-latency links, such as remote control of critical infrastructure and self-driving vehicles. Reliability and latency levels are critical for smart grid control, industrial automation, robotics, drone control and coordination, etc.

[0047] Now, multiple use cases in a 5G communication system including an NR system will be described in detail.

[0048] 5G can complement fiber-to-the-home (FTTH) and cable-based broadband (or cable data service interface specification (DOCSIS)) as a means of delivering streams at data rates ranging from hundreds of megabits per second to gigabits per second. Such high speeds are needed for television broadcasts with resolutions of 4K (6K, 8K, and higher) or above, as well as virtual reality (VR) and AR. VR and AR applications mainly include immersive sports games. Specific applications may require special network configurations. For example, for VR games, gaming companies may have to integrate core servers with network operators' edge network servers in order to minimize latency.

[0049] The automotive industry is expected to become a very important new driver for 5G, where many use cases are used for mobile communications in vehicles. For example, entertainment for passengers requires mobile broadband with both high capacity and high mobility, as future users will expect to continue their good quality connection independently of their location and speed. Other use cases for the automotive industry are AR dashboards. These displays overlay information on what the driver sees through the front window, identifying objects in the dark and telling the driver the distance and movement of objects. In the future, wireless modules will enable communication between the vehicles themselves, between the vehicle and the supporting infrastructure, and between the vehicle and other connected devices (e.g., those carried by pedestrians). Safety systems can guide drivers in alternative courses of action to allow them to drive more safely and reduce the risk of accidents. The next stage will be remote-controlled or self-driving vehicles. These require very reliable, very fast communication between different self-driving vehicles and between vehicles and infrastructure. In the future, self-driving vehicles will perform all driving activities, while the driver will focus on the elusive traffic anomalies in the vehicle itself. The technical needs of self-driving vehicles require ultra-low latency and ultra-high reliability, raising traffic safety to a level that people cannot achieve.

[0050] Smart cities and smart homes (often referred to as smart societies) will be embedded with dense wireless sensor networks. Distributed networks of smart sensors will identify conditions for cost and energy efficiency maintenance in cities or homes. A similar setup can be done for each home, where temperature sensors, window and heating controls, burglar alarms, and home appliances are all wirelessly connected. Many of these sensors are typically characterized by low data rates, low power, and low cost, but real-time high-definition (HD) video may be required for monitoring in certain types of equipment, for example.

[0051] The consumption and distribution of energy (including heat or gas) is becoming highly decentralized, creating a need for automatic control of very distributed sensor networks. Smart grids interconnect these sensors, using digital information and communication technologies to collect and act on information. This information can include information about the behavior of suppliers and consumers, allowing smart grids to improve the efficiency, reliability, economy, and sustainability of the production and distribution of fuels such as electricity in an automated manner. Smart grids can be viewed as another sensor network with low latency.

[0052] The health sector has many applications that can benefit from mobile communications. Communication systems enable telemedicine that provides remote clinical health care. It helps eliminate distance barriers and can improve access to medical services that are not always available in remote rural communities. It is also used to save lives in critical care and emergency situations. Wireless sensor networks based on mobile communications can provide remote monitoring and sensors for parameters such as heart rate and blood pressure.

[0053] Wireless and mobile communications are becoming increasingly important for industrial applications. Wires are expensive to install and maintain, and the possibility of replacing them with reconfigurable wireless links is an attractive opportunity for many industries. However, achieving this requires wireless connections to work with similar latency, reliability, and capacity as cables, and to simplify their management. Low latency and very low probability of error are new requirements that need to be addressed with 5G.

[0054] Finally, logistics and freight tracking are important use cases for mobile communications, which enable tracking of inventory and packages anytime, anywhere by using location-based information systems. Logistics and freight tracking use cases typically require lower data rates but require wide coverage and reliable location information.

[0055] Figure 1 Illustrated is a diagram of physical channels in a 3GPP system and a general signal transmission method using the physical channels.

[0056] When the UE is powered on or enters a new cell, the UE performs an initial cell search (S11). The initial cell search involves the acquisition of synchronization with the BS. To this end, the UE receives a synchronization signal block (SSB) from the BS. The SSB includes a primary synchronization signal (PSS), a secondary synchronization signal (SSS), and a physical broadcast channel (PBCH). The UE synchronizes its timing with the BS and obtains information such as a cell identifier (ID) based on the PSS / SSS. In addition, the UE can obtain information broadcast in the cell by receiving a PBCH from the BS. During the initial cell search, the UE can also monitor the DL channel status by receiving a downlink reference signal (DL RS).

[0057] After the initial cell search, the UE may acquire more detailed system information by receiving a physical downlink control channel (PDCCH) and a physical downlink shared channel (PDSCH) corresponding to the PDCCH (S12).

[0058] Subsequently, in order to complete the connection to the BS, the UE may perform a random access procedure with the BS (S13 to S16). Specifically, the UE may send a preamble on a physical random access channel (PRACH) (S13), and may receive a PDCCH and a random access response (RAR) to the preamble on a PDSCH corresponding to the PDCCH (S14). The UE may then send a physical uplink shared channel (PUSCH) by using the scheduling information in the RAR (S15), and perform a contention resolution procedure including receiving a PDCCH and a PDSCH signal corresponding to the PDCCH (S16).

[0059] When the random access procedure is performed in two steps, steps S13 and S15 may be performed as one step (wherein message A is transmitted by the UE), and steps S14 and S16 may be performed as one step (wherein message B is transmitted by the BS).

[0060] After the above process, in the general UL / DL signal transmission process, the UE can receive PDCCH and / or PDSCH from the BS (S17), and send a physical uplink shared channel (PUSCH) and / or a physical uplink control channel (PUCCH) to the BS (S18). The control information sent by the UE to the BS is generally referred to as uplink control information (UCI). UCI includes hybrid automatic repeat and request acknowledgment / negative acknowledgment (HARQ-ACK / NACK), scheduling request (SR), channel state information (CSI), etc. CSI includes channel quality indicator (CQI), precoding matrix index (PMI), rank indication (RI), etc. Typically, UCI is sent on PUCCH. However, if control information and data should be sent at the same time, control information and data can be sent on PUSCH. In addition, upon receiving a request / command from the network, the UE can send UCI on PUSCH irregularly.

[0061] Figure 2 The radio frame structure is shown.

[0062] In NR, UL and DL transmissions are configured in frames. Each radio frame has a length of 10 milliseconds and is divided into two half-frames of 5ms. Each half-frame is divided into five 1ms subframes. A subframe is divided into one or more time slots, and the number of time slots in a subframe depends on the subcarrier spacing (SCS). Depending on the cyclic prefix (CP), each time slot includes 12 or 14 OFDM (A) symbols. When a normal CP is used, each time slot includes 14 OFDM symbols. When an extended CP is used, each time slot includes 12 OFDM symbols. Symbols may include OFDM symbols (or CP-OFDM symbols) and SC-FDMA symbols (or discrete Fourier transform-extended OFDM (DFT-s-OFDM) symbols).

[0063] Table 1 exemplarily illustrates that the number of symbols per slot, the number of slots per frame, and the number of slots per subframe vary according to SCS in the normal CP case.

[0064] [Table 1]

[0065] SCS(15*2^u) Nslotsymb Nframe,uslot Nsubframe,uslot 15KHz(u=0) 14 10 1 30KHz(u=1) 14 20 2 60KHz(u=2) 14 40 4 120KHz(u=3) 14 80 8 240KHz(u=4) 14 160 16

[0066] *Nslotsymb: number of symbols in a slot

[0067] *Nframe,uslot: number of time slots in a frame

[0068] *Nsubframe,uslot: number of time slots in a subframe

[0069] Table 2 illustrates that the number of symbols per slot, the number of slots per frame, and the number of slots per subframe vary according to SCS in the extended CP case.

[0070] [Table 2]

[0071] SCS(15*2^u) Nslotsymb Nframe,uslot Nsubframe,uslot 60KHz(u=2) 12 40 4

[0072] The frame structure is only an example, and the number of subframes, the number of time slots, and the number of symbols in the frame can be changed in various ways. In the NR system, different OFDM (A) parameter sets (e.g., SCS, CP length, etc.) can be configured for multiple cells aggregated for one UE. Therefore, the (absolute time) duration of a time resource (e.g., a subframe, a time slot, or a transmission time interval (TTI)) consisting of the same number of symbols (for convenience, referred to as a time unit (TU)) can be configured differently between aggregated cells.

[0073] In NR, various parameter sets (or SCS) can be supported to support various fifth generation (5G) services. For example, with an SCS of 15kHz, wide areas in traditional cellular bands can be supported, while with an SCS of 30kHz or 60kHz, dense urban areas, lower latency, and wide carrier bandwidths can be supported. With an SCS of 60kHz or higher, bandwidths greater than 24.25kHz can be supported to overcome phase noise.

[0074] The NR band can be defined by two types of frequency ranges (FR1 and FR2). FR1 and FR2 can be configured as described in Table 3 below. FR2 can be millimeter wave (mmW).

[0075] [Table 3]

[0076] Frequency range specification Corresponding frequency range Subcarrier spacing FR1 450MHz-7125MHz 15,30,60kHz FR2 24250MHz-52600MHz 60,120,240kHz

[0077] Figure 3 The resource grid during the duration of a time slot is illustrated. A time slot includes multiple symbols in the time domain. For example, a time slot includes 14 symbols in the normal CP case and 12 symbols in the extended CP case. A carrier includes multiple subcarriers in the frequency domain. A resource block (RB) can be defined by multiple (e.g., 12) consecutive subcarriers in the frequency domain. A bandwidth part (BWP) can be defined by multiple consecutive (physical) RBs ((P)RBs) in the frequency domain and corresponds to a parameter set (e.g., SCS, CP length, etc.). A carrier can include up to N (e.g., 5) BWPs. Data communication can be performed in an active BWP, and a UE can only activate one BWP. Each element in the resource grid can be called a resource element (RE) to which a complex symbol can be mapped.

[0078] Figure 4 An exemplary mapping of physical channels in time slots is illustrated.

[0079] DL control channel, DL or UL data and UL control channel can all be included in one time slot. For example, the first N symbols in the time slot (hereinafter referred to as the DL control region) can be used to send the DL control channel, and the last M symbols in the time slot (hereinafter referred to as the UL control region) can be used to send the UL control channel. N and M are integers equal to or greater than 0. The resource area (hereinafter referred to as the data area) between the DL control area and the UL control area can be used for DL ​​data transmission or UL data transmission. A time gap for DL ​​to UL or UL to DL switching can be defined between the control area and the data area. PDCCH can be sent in the DL control area, and PDSCH can be sent in the DL data area. Some symbols when switching from DL to UL in the time slot can be configured as time gaps.

[0080] Now, a detailed description will be given of the physical channels.

[0081] UL channel structure

[0082] The UE transmits a relevant signal to the BS on a UL channel to be described later, and the BS receives a relevant signal from the UE through the UL channel to be described later.

[0083] (1) Physical Uplink Control Channel (PUCCH)

[0084] The PUCCH carries UCI, HARQ-ACK and / or Scheduling Request (SR), and is divided into a short PUCCH and a long PUCCH according to a PUCCH transmission length.

[0085] The UCI includes the following information.

[0086] -SR: Information used to request UL-SCH resources.

[0087] -HARQ-ACK: A response to a DL data packet (e.g., codeword) on the PDSCH. HARQ-ACK indicates whether the DL data packet has been successfully received. In response to a single codeword, a 1-bit HARQ-ACK may be sent. In response to two codewords, a 2-bit HARQ-ACK may be sent. The HARQ-ACK response includes a positive ACK (abbreviated as ACK), a negative ACK (NACK), a discontinuous transmission (DTX), or NACK / DTX. The term HARQ-ACK is used interchangeably with HARQ ACK / NACK and ACK / NACK.

[0088] -CSI: Feedback information for DL ​​channels. Feedback information related to Multiple Input Multiple Output (MIMO) includes RI and PMI.

[0089] Table 4 illustrates an exemplary PUCCH format. Based on PUCCH transmission duration, the PUCCH format may be divided into short PUCCH (formats 0 and 2) and long PUCCH (formats 1, 3, and 4).

[0090] [Table 4]

[0091]

[0092] PUCCH format 0 conveys up to 2 bits of UCI and is mapped in a sequence-based manner for transmission. Specifically, the UE sends a specific UCI to the BS by sending one of multiple sequences on the PUCCH of PUCCH format 0. Only when the UE sends a positive SR, the UE sends the PUCCH of PUCCH format 0 in the PUCCH resources used for the corresponding SR configuration. PUCCH format 1 conveys up to 2 bits of UCI and spreads the modulation symbols of the UCI in the time domain with an orthogonal cover code (OCC) (which is configured differently depending on whether frequency hopping is performed). DMRS is transmitted in symbols in which modulation symbols are not transmitted (i.e., transmitted in time division multiplexing (TDM)).

[0093] PUCCH format 2 conveys more than 2 bits of UCI, and the modulation symbols of DCI are sent with DMRS in frequency division multiplexing (FDM). DMRS are located in symbols #1, #4, #7, and #10 of a given RB with a density of 1 / 3. Pseudo-noise (PN) sequences are used for DMRS sequences. For 2-symbol PUCCH format 2, frequency hopping can be activated.

[0094] PUCCH format 3 does not support UE multiplexing in the same PRBS and conveys UCI of more than 2 bits. In other words, the PUCCH resources of PUCCH format 3 do not include OCC. The modulation symbols and DMRS are transmitted in TDM.

[0095] PUCCH format 4 supports multiplexing of up to 4 UEs in the same PRBS and conveys more than 2 bits of UCI. In other words, the PUCCH resources of PUCCH format 3 include OCC. The modulation symbols and DMRS are transmitted in TDM.

[0096] (2) Physical Uplink Shared Channel (PUSCH)

[0097] The PUSCH carries UL data (e.g., UL shared channel transport block (UL-SCH TB)) and / or UL control information (UCI), and is transmitted based on a cyclic prefix-orthogonal frequency division multiplexing (CP-OFDM) waveform or a discrete Fourier transform-spread-orthogonal frequency division multiplexing (DFT-s-OFDM) waveform. When the PUSCH is transmitted based on the DFT-s-OFDM waveform, the UE transmits the PUSCH by applying transform precoding. For example, when transform precoding is not allowed (e.g., transform precoding is disabled), the UE may transmit the PUSCH based on the CP-OFDM waveform. When transform precoding is allowed (e.g., transform precoding is enabled), the UE may transmit the PUSCH based on the CP-OFDM waveform or the DFT-s-OFDM waveform. PUSCH transmission may be dynamically scheduled by a UL grant in the DCI, or may be semi-statically scheduled based on higher layer (e.g., RRC) signaling (and / or layer 1 (L1) signaling (e.g., PDCCH)) (configured grant). PUSCH transmission may be performed on a codebook basis or a non-codebook basis.

[0098] Figure 5 It is a diagram for explaining HARQ-ACK transmission timing and PUSCH transmission timing and an assignment method.

[0099] HARQ-ACK is information indicating whether the UE has successfully received the physical DL channel. When the physical DL channel is successfully received, the UE feeds back an acknowledgement (ACK) to the BS and, otherwise, the UE feeds back a negative ACK (NACK) to the BS. In NR, HARQ supports 1-bit HARQ-ACK feedback per transport block. Figure 5 An example of HARQ-ACK timing K1 is illustrated.

[0100] exist Figure 5 In, K0 represents the number of slots from the slot with the PDCCH carrying DL assignment (i.e., DL grant) to the slot with the corresponding PDSCH transmission, K1 represents the number of slots from the slot with the PDSCH to the slot with the corresponding HARQ-ACK transmission, and K2 represents the number of slots from the slot with the PDCCH carrying UL grant to the slot with the corresponding PUSCH transmission. That is, K0, K1, K2 can be simply summarized as shown in Table 5 below.

[0101] [Table 5]

[0102] A B K0 DL Scheduling DCI Corresponding DL data transmission K1 DL data reception Corresponding HARQ-ACK K2 UL Scheduling DCI Corresponding UL data transmission

[0103] The BS can provide HARQ-ACK feedback timing to the UE dynamically through DCI or semi-statically through RRC signaling. The NR system supports different minimum HARQ processing times for UEs. The HARQ processing time includes the delay between the DL data reception timing and the corresponding HARQ-ACK transmission timing and the delay between the UL grant reception timing and the corresponding UL data transmission timing. The UE sends information about its minimum HARQ processing time capability to the BS. From the UE's perspective, HARQ ACK / NACK feedback signals for multiple DL transmissions in the time domain can be sent in one UL data / control region. The timing between DL data reception and the corresponding ACK is indicated by the DCI.

[0104] Unlike LTE systems that perform transport block (TB)-based or codeword-based HARQ processes, NR systems support code block group (CBG)-based transmissions for single-bit / multi-bit HARQ-ACK feedback. TBs can be mapped to one or more code blocks (CBs) according to their size. For example, during the channel coding process, a cyclic redundancy check (CRC) code is attached to the TB. If the CRC-attached TB is not larger than a specific size, the CRC-attached TB corresponds to one CB. However, if the CRC-attached TB is larger than a specific size, the CRC-attached TB is divided into multiple CBs. In the NR system, the UE can be configured to receive CBG-based transmissions and can schedule retransmissions to carry a subset of all CBs of the TB.

[0105] refer to Figure 5 , the UE may detect the PDCCH in time slot #n. The PDCCH includes DL scheduling information (e.g., DCI format 1_0 and / or DCI format 1_1). The PDCCH indicates a DL assignment-to-PDSCH offset K0 and a PDSCH-to-HARQ-ACK reporting offset K1. For example, DCI format 1_0 and DCI format 1_1 may include the following information.

[0106] - Frequency domain resource assignment: indicates RB resources (eg, one or more (non-)contiguous RBs) assigned to the PDSCH.

[0107] - Time domain resource assignment: Indicates K0 and the starting position (eg, OFDM symbol index) and length (eg, number of OFDM symbols) of the PDSCH in a time slot.

[0108] -PDSCH-to-HARQ_feedback timing indicator: indicates K1.

[0109] - HARQ process number (4 bits): indicates the HARQ process identification (ID) of the data (eg, PDSCH or TB).

[0110] - PUCCH resource indicator (PRI): indicates a PUCCH resource to be used for UCI transmission among a plurality of PUCCH resources in a PUCCH resource set.

[0111] Next, the UE can receive the PDSCH in time slot #(n+K0) according to the scheduling information of time slot #n, and then send UCI on the PUCCH in time slot #(n+K1). The UCI includes a HARQ-ACK response to the PDSCH. In the case where the PDSCH is configured to carry a maximum of one TB, the HARQ-ACK response can be configured as 1 bit. In the case where the PDSCH is configured to carry a maximum of two TBs, if spatial bundling is not configured, the HARQ-ACK response can be configured as two bits, and if spatial bundling is configured, it can be configured as one bit. When time slot #(n+K1) is designated as the HARQ-ACK transmission timing for multiple PDSCHs, the UCI sent in time slot #(n+K1) includes HARQ-ACK responses to multiple PDSCHs.

[0112] refer to Figure 5 , the UE may detect the PDCCH in time slot #n. The PDCCH includes UL scheduling information (eg, DCI format 0_0 and / or DCI format 0_1). DCI format 0_0 and DCI format 0_1 ​​may include the following information.

[0113] - Frequency domain resource assignment: indicates the RB set assigned to the PUSCH.

[0114] -Time domain resource assignment: indicates the slot offset K2 and the starting position (eg, symbol index) and length (eg, number of OFDM symbols) of the PUSCH in the slot. The starting symbol and length may be indicated by a start and length indicator value (SLIV) or may be indicated separately.

[0115] Thereafter, the UE may transmit the PUSCH in slot #(n+k2) according to the scheduling information of slot #n. Here, the PUSCH includes the UL-SCH TB.

[0116] DL channel structure

[0117] The eNB transmits a relevant signal to the UE on a DL channel described later, and the UE receives a relevant signal from the eNB on the DL channel.

[0118] (1) Physical Downlink Shared Channel (PDSCH)

[0119] PDSCH carries DL data (e.g., DL shared channel transport block (DL-SCH TB)) and adopts modulation schemes such as quadrature phase shift keying (QPSK), 16-ary quadrature amplitude modulation (16QAM), 64-ary QAM (64QAM) or 256-ary QAM (256QAM). TB is encoded as a codeword. PDSCH can deliver up to two codewords. The codewords are subjected to scrambling and modulation mapping separately, and the modulation symbols from each codeword are mapped to one or more layers. OFDM signals are generated by mapping each layer to resources together with DMRS, and the OFDM signals are sent through corresponding antenna ports.

[0120] (2) Physical Downlink Control Channel (PDCCH)

[0121] PDCCH delivers DCI. For example, PDCCH (i.e., DCI) can carry information about the transmission format and resource allocation of the DL shared channel (DL-SCH), resource allocation information of the uplink shared channel (UL-SCH), paging information about the paging channel (PCH), system information about DL-SCH, information about resource allocation of higher-layer control messages (such as RAR sent on PDSCH), transmit power control commands, information about activation / release of configured scheduling, etc. DCI includes a cyclic redundancy check (CRC). Depending on the owner or purpose of the PDCCH, the CRC is masked with various identifiers (IDs) (e.g., radio network temporary identifiers (RNTI)). For example, if the PDCCH is for a specific UE, the CRC is masked by the UE ID (e.g., cell RNTI (C-RNTI)). If the PDCCH is used for a paging message, the CRC is masked by the paging RNTI (P-RNTI). If the PDCCH is used for system information (e.g., system information block (SIB)), the CRC is masked by the system information RNTI (SI-RNTI). When the PDCCH is used for RAR, the CRC is masked by a random access RNTI (RA-RNTI).

[0122] PDCCH uses a fixed modulation scheme (e.g., QPSK). One PDCCH includes 1, 2, 4, 8, or 16 control channel elements (CCEs) depending on its aggregation level (AL). One CCE includes 6 resource element groups (REGs), each REG being defined by one OFDM symbol by one (P)RB.

[0123] Figure 6 The figure shows an exemplary structure of a REG. Figure 6 In FIG. 1 , D represents an RE to which DCI is mapped, and R represents an RE to which DMRS is mapped. DMRS is mapped to RE#1, RE#5, and RE#9 along the frequency direction in one symbol.

[0124] The PDCCH is transmitted in a control resource set (CORESET). A CORESET corresponds to a set of physical resources / parameters for delivering PDCCH / DCI in a BWP. For example, a CORESET is defined as a set of REGs with a given set of parameters (e.g., SCS, CP length, etc.). A CORESET may be configured by system information (e.g., a master information block (MIB)) or UE-specific higher layer signaling (e.g., RRC signaling). For example, the following parameters / information may be used to configure a CORESET, and multiple CORESETs may overlap each other in the time / frequency domain.

[0125] -controlResourceSetId: indicates the ID of the CORESET.

[0126] -frequencyDomainResources: Indicates the frequency domain resources of the CORESET. The frequency domain resources are indicated by a bitmap, and each bit of the bitmap corresponds to an RB group (i.e., six consecutive RBs). For example, the most significant bit (MSB) of the bitmap corresponds to the first RB group of the BWP. The RB group corresponding to the bit set to 1 is allocated as the frequency domain resource of the CORESET.

[0127] -Duration: Indicates the time region resource of CORESET. It indicates the number of consecutive OFDMA symbols in CORESET. For example, the duration is set to one of 1 to 3.

[0128] -cce-REG-MappingType: indicates the CCE to REG mapping type. Both interleaved and non-interleaved types are supported.

[0129] -precoderGranularity: Indicates the precoder granularity in the frequency domain.

[0130] -tci-StatesPDCCH: Provides information indicating the transmission configuration indication (TCI) state for PDCCH (eg, TCI-StateID). TCI state is used to provide a quasi-co-location relationship between (one or more) DL RSs in an RS set (TCI state) and a PDCCH DMRS port.

[0131] -tci-PresentInDCI: Indicates whether the TCI field is included in the DCI.

[0132] -pdcch-DMRS-ScramblingID: Provides information for initializing the PDCCH DMRS scrambling sequence.

[0133] For each CORESET, the precoder granularity in the frequency domain is set to one of the following via higher layer signaling:

[0134] -sameAsREG-bundle: It is equal to the REG bundle size in the frequency domain.

[0135] -allContiguousRBs: This is equal to the number of contiguous RBs in the frequency domain within CORESET.

[0136] The REGs of a CORESET are numbered in a time-first mapping manner, that is, the REGs are numbered sequentially in ascending order, starting from 0 for the first OFDM symbol of the lowest numbered RB in the CORESET.

[0137] The CCE to REG mapping for CORESET can be of interleaved type or non-interleaved type. Figure 7 (a) is a diagram illustrating non-interleaved CCE-REG mapping, and Figure 7 (b) is a diagram illustrating interleaved CCE-REG mapping.

[0138] - Non-interleaved CCE to REG mapping (or centralized CCE to REG mapping): 6 REGs of a given CCE are grouped into one REG bundle, and all REGs of a given CCE are continuous. One REG bundle corresponds to one CCE.

[0139] - Interleaved CCE to REG mapping (or distributed CCE to REG mapping): 2, 3, or 6 REGs of a given CCE are grouped into one REG bundle, and the REG bundle is interleaved in a CORESET. In a CORESET consisting of one or two OFDM symbols, the REG bundle includes 2 or 6 REGs, and in a CORESET consisting of three OFDM symbols, the REG bundle includes 3 or 6 REGs. The REG bundle size is configured on a CORESET basis.

[0140] Figure 8 An exemplary block interleaver is shown. For the above interleaving operation, the number of rows A in the (block) interleaver is set to 1 or 2, 3, and 6. When the number of interleaving units of a given CORESET is P, the number of columns in the block interleaver is P / A. In the block interleaver, Figure 8 As illustrated, the write operation is performed in a row-first direction, and the read operation is performed in a column-first direction.A cyclic shift (CS) of the interleaving unit is applied based on an ID that is configurable independently of the configurable ID for the DMRS.

[0141] To receive the PDCCH, the UE may monitor (e.g., blindly decode) a set of PDCCH candidates in a CORESET. A PDCCH candidate is a CCE(s) that the UE monitors for PDCCH reception / detection. PDCCH monitoring may be performed in one or more CORESETs in an active DL BWP on each active cell configured with PDCCH monitoring. The set of PDCCH candidates monitored by the UE is defined as a PDCCH search space (SS) set. An SS set may be a common search space (CSS) set or a UE-specific search space (USS) set.

[0142] Table 6 lists exemplary PDCCH SSs.

[0143] [Table 6]

[0144]

[0145]

[0146] The SS set may be configured by system information (e.g., MIB) or UE-specific higher layer (e.g., RRC) signaling. S or fewer SS sets may be configured in each DL BWP of a serving cell. For example, the following parameters / information may be provided for each SS set. Each SS set may be associated with one CORESET, and each CORESET configuration may be associated with one or more SS sets. -searchSpaceId: indicates the ID of the SS set.

[0147] -controlResourceSetId: Indicates the CORESET associated with the SS set.

[0148] - monitoringSlotPeriodicityAndOffset: indicates the PDCCH monitoring periodicity (in time slots) and the PDCCH monitoring offset (in time slots).

[0149] - monitoringSymbolsWithinSlot: Indicates the first OFDMA symbol(s) used for PDCCH monitoring in a slot configured with PDCCH monitoring. The OFDMA symbols are indicated by a bitmap, and each bit of the bitmap corresponds to an OFDM symbol in the slot. The MSB of the bitmap corresponds to the first OFDM symbol of the slot. The OFDMA symbol(s) corresponding to the bit(s) set to 1 correspond to the first symbol(s) of the CORESET in the slot.

[0150] -nrofCandidates: indicates the number of PDCCH candidates for each AL={1,2,4,8,16} (eg, one of 0, 1, 2, 3, 4, 5, 6, and 8).

[0151] -searchSpaceType: Indicates whether the SS type is CSS or USS.

[0152] -DCI format: indicates the DCI format of the PDCCH candidate.

[0153] The UE may monitor PDCCH candidates in one or more SS sets in a time slot based on the CORESET / SS set configuration. The timing (e.g., time / frequency resources) at which PDCCH candidates should be monitored is defined as a PDCCH (monitoring) opportunity. One or more PDCCH (monitoring) opportunities may be configured in a time slot.

[0154] Table 7 illustrates an exemplary DCI format transmitted on the PDCCH.

[0155] [Table 7]

[0156]

[0157] DCI format 0_0 can be used to schedule TB-based (or TB-level) PUSCH, and DCI format 0_1 ​​can be used to schedule TB-based (or TB-level) PUSCH or code block group (CBG) (or CBG level) PUSCH. DCI format 1_0 can be used to schedule TB-based (or TB-level) PDSCH, and DCI format 1_1 can be used to schedule TB-based (or TB-level) PDSCH or CBG (or CBG level) based PDSCH (DL grant DCI). DCI format 0_0 / 0_1 can be referred to as UL grant DCI or UL scheduling information, and DCI format 1_0 / 1_1 can be referred to as DL grant DCI or DL ​​scheduling information. DCI format 2_0 is used to deliver dynamic slot format information (e.g., dynamic slot format indicator (SFI)) to the UE, and DCI format 2_1 is used to deliver DL preemption information to the UE. DCI format 2_0 and / or DCI format 2_1 may be delivered to a corresponding group of UEs on a group common PDCCH, which is a PDCCH for a group of UEs. DCI format 0_0 and DCI format 1_0 may be referred to as fallback DCI formats, while DCI format 0_1 ​​and DCI format 1_1 may be referred to as non-fallback DCI formats. In the fallback DCI format, the DCI size / field configuration remains the same regardless of the UE configuration. In contrast, the DCI size / field configuration varies in the non-fallback DCI format depending on the UE configuration.

[0158] Bandwidth Part (BWP)

[0159] The NR system can support up to 400MHz per carrier. If a UE operating in such a wideband carrier always keeps the radio frequency (RF) module turned on for the entire carrier, the UE may suffer a lot of battery consumption. Considering multiple use cases in one wideband carrier (e.g., eMBB, URLLC, mMTC, V2X, etc.), different parameter sets (e.g., subcarrier spacing) can be supported for different frequency bands of the carrier. Each UE may have different capabilities regarding the maximum bandwidth. At this point, the eNB can instruct the UE to operate only in part of the bandwidth of the wideband carrier, rather than across the total bandwidth. Such a partial bandwidth is called a BWP. A BWP is a subset of contiguous common resource blocks defined for a parameter set μi in BWP i in the frequency domain, and a parameter set (e.g., subcarrier spacing, CP length, or slot / microslot duration) can be configured for the BWP.

[0160] The gNB may configure one or more BWPs in one carrier configured for the UE. If the UEs are concentrated in a specific BWP, some UEs may switch to another BWP for load balancing. For frequency domain inter-cell interference elimination between adjacent cells, BWPs at both ends of the total bandwidth of the cell except for some center spectrum may be configured in the same time slot. That is, the gNB may configure at least one DL / UL BWP for the UE associated with the wideband carrier, activate at least one of the DL / UL BWPs configured at a specific time (through L1 signaling as a physical layer control signal, MAC control element (CE) as a MAC layer control signal, or RRC signaling), instruct the UE to switch to another configured DL / UL BWP (through L1 signaling, MAC CE, or RRC signaling), or set a timer value and switch the UE to a predetermined DL / UL BWP when the timer value expires. In order to indicate switching to another configured DL / UL BWP, DCI format 1_1 or DCI format 0_1 ​​may be used. Specifically, the activated DL / UL BWP is referred to as an active DL / UL BWP. During initial access or before RRC connection establishment, the UE may not receive a DL / UL BWP configuration. The DL / UL BWP assumed by the UE in this case is referred to as the initial active DL / UL BWP.

[0161] The DL BWP is a BWP for transmitting and receiving DL signals such as PDCCH and / or PDSCH, and the UL BWP is a BWP for transmitting and receiving UL signals such as PUCCH and / or PDSCH.

[0162] The present disclosure proposes a method of extending a PDCCH monitoring gap to a plurality of time slots longer than one time slot, so as to achieve power saving of a UE and reduce a load caused by excessive PDCCH monitoring.

[0163] The PDCCH monitoring gap may be defined as the gap between the start times of the unit in which the UE monitors the PDCCH. For example, in the Release 15 NR system, PDCCH monitoring is performed in units of one slot, and the start time of PDCCH monitoring is the start symbol of one slot. Therefore, the interval between the start symbol of the first slot and the start symbol of the second slot is one slot. Therefore, the existing PDCCH monitoring gap may be considered as one slot.

[0164] A maximum of 10 SS sets per BWP may be configured for the UE. The UE may monitor PDCCH candidates included in the SS set (hereinafter, SS set monitoring).

[0165] Since the UE should perform blind decoding (BD) on the PDCCH in a state in which the UE does not know when the PDCCH will be received and which DCI format will be received, PDCCH monitoring accounts for a large part in power consumption.

[0166] The maximum number of PDCCH candidates that a UE can monitor based on a timeslot is limited. For example, for each SCS defined in standard document 38.213, the maximum number of PDCCH candidates that a UE can monitor per timeslot and per serving cell (hereinafter referred to as "BD limit") can be defined as shown in [Table 8].

[0167] In addition, for each SCS defined in the standard document 38.213, the maximum number of non-overlapping CCEs per time slot and per serving cell (hereinafter referred to as "CCE limit") can be defined as shown in [Table 9].

[0168] [Table 8]

[0169]

[0170] [Table 9]

[0171]

[0172] As an energy saving technology for future wireless communication systems (e.g., Release 17 NR systems) or a load reduction technology for UEs, the maximum number of PDCCH candidates that the UE can monitor per time slot, as defined in [Table 8], can be applied to X time slots to reduce the number of PDCCH monitoring times of the UE, where X can be a natural number greater than 1. Thus, the effect of reducing the number of monitoring times and the number of BDs in the total operating time of the UE can be obtained.

[0173] To extend the PDCCH monitoring gap, various operations and variables (e.g., X value, SS set drop rule, priority of SS set, and Y slots corresponding to a new window for applying a drop rule when the drop rule is not applicable to the entire X slot) may be defined. The BD limit and the CCE limit may respectively mean the number of PDCCH candidates (e.g., the number of BDs) and the number of CCEs that the UE should monitor during a unit time.

[0174] If the UE is able to receive an indication for extending the PDCCH monitoring gap, there may be great advantages in terms of UE power consumption and the load required to perform a large amount of monitoring in a short period of time can be reduced. To this end, the relevant variables may be preconfigured / indicated by a higher layer (e.g., a radio resource control (RRC) layer).

[0175] Therefore, an embodiment of the present disclosure proposes a method for extending the PDCCH monitoring gap of a UE. To this end, an X time slot value as an extended PDCCH monitoring gap, a new SS set discard rule, a Y time slot value for applying the discard rule, etc. can be defined. In addition, UE / BS operations associated with the SS set configuration related to the PDCCH monitoring gap are defined.

[0176] Hereinafter, methods, embodiments or options will be described separately to make the explanation clear, and should not be interpreted restrictively as meaning that they are independently performed. For example, [Embodiment #1] to [Embodiment #4] described later can be implemented separately, but at least some of them can be implemented in combination within the scope that does not conflict with each other.

[0177] Before describing the present disclosure in detail, the overall operation procedures of a UE and a BS according to an embodiment of the present disclosure will now be described.

[0178] Fig. 9 is a diagram for explaining an overall operation procedure of a UE and a BS according to an embodiment of the present disclosure.

[0179] refer to Fig. 9 , the UE may receive first information about the SS set and / or second information related to the PDCCH monitoring gap from the BS (S901). In this case, the UE may receive the first information and / or the second information through the RRC. The second information may include, for example, at least one of an X time slot value when the PDCCH monitoring gap is extended, a new SS set discard rule, a Y time slot value for applying the discard rule, or a periodicity of SS set monitoring for the extended PDCCH monitoring gap. The first information may include multiple pieces of information about the SS set. The second information may also include multiple pieces of information related to the PDCCH monitoring gap.

[0180] For example, the second information may include a plurality of X time slot values, an SS set discarding rule, a Y time slot value, and / or a periodicity of SS set monitoring for extending the PDCCH monitoring gap.

[0181] The detailed operation of S901 can be based on [Embodiment #1] to [Embodiment #4].

[0182] The UE may send capability information of the PDCCH monitoring gap to the BS in order to extend the PDCCH monitoring gap (S903). The UE may send capability information in the form of (X, Y) which is a combination of an X time slot value and a Y time slot value through RRC signaling and / or UCI. The detailed operation for this information transmission may be based on [Embodiment #4].

[0183] The UE may receive third information related to the PDCCH monitoring gap (S905). For example, if multiple pieces of information related to the PDCCH monitoring gap are included in the second information of step S901, any one of the multiple pieces of information may be indicated by downlink control information (DCI) or MAC CE.

[0184] The detailed operation of step S905 may be based on [Embodiment #1] to [Embodiment #4].

[0185] In step S903, when it is determined that power saving of the UE is required or load reduction is required, the UE may issue a request for such determination to the BS.

[0186] If it is determined that the BS does not have information / channel to be transmitted to the UE within a predetermined time even when the UE does not transmit capability information, the third information may be indicated for power saving of the UE.

[0187] That is, only one of the two steps S903 and S905 may be selectively performed. For example, if step S903 is performed, step S905 may be omitted, and if step S903 is omitted, step S905 may be performed. Alternatively, both steps S903 and S905 may be omitted according to the operation related to the timer described later.

[0188] However, it is obvious that steps S903 and S905 can be operated together. For example, if the UE sends multiple (X, Y) combinations in step S903, the BS can include any one of the multiple (X, Y) combinations in the third information and send the third information to the UE.

[0189] When a timer related to data transmission (eg, a timer associated with a MAC timer or a discontinuous reception (DRX) timer or configured separately) expires, it can be expected that the UE and the BS will perform operations for extending the PDCCH monitoring gap without a separate indication or request.

[0190] The above capability information transmission of the UE and / or the indication of the BS may be initiated through DCI and / or UCI and is not limited to a specific format. The above capability information transmission of the UE and / or the indication of the BS may also be performed through MAC CE or RRC.

[0191] The above-mentioned capability information transmission of the UE, the indication of the BS, and the operation of the timer are called triggering.

[0192] The PDCCH monitoring gap may be extended after a predetermined time from the trigger. The predetermined time may be predefined, or information about it may be sent to the UE via RRC signaling and / or DCI. Thus, the PDCCH monitoring start timing caused by the extended PDCCH monitoring gap may be determined.

[0193] To indicate release / termination of UE operation based on PDCCH monitoring gap extension, the same method as any one of the methods for initiating UE operation based on PDCCH monitoring gap extension (eg, the above three triggering operations) may be used.

[0194] The BS may transmit a PDCCH to the UE based on the information about the SS set dropping rule and / or the PDCCH monitoring gap based on the first information, the second information, and / or the third information (S907).

[0195] The UE may monitor and receive the PDCCH based on the information about the SS set dropping rule and / or the PDCCH monitoring gap based on the first information, the second information, and / or the third information ( S909 ).

[0196] Detailed operations of the UE and the BS based on S907 and S909 may be based on [Embodiment #1] to [Embodiment #4].

[0197] The UE may perform the operations proposed in the present disclosure even without a trigger. For example, in special cases, such as where a problem occurs in the RRC configuration or where the UE needs to save power urgently even if the PDCCH monitoring gap extension is not indicated, the UE may determine to perform the PDCCH monitoring gap extension operation. For example, in the case where the battery capacity of the UE is very low (e.g., when the battery is less than a predetermined threshold), it may be assumed that the UE performs a random access procedure while performing a cell handover.

[0198] When the PDCCH monitoring gap extension is initiated, the UE may continue to perform an operation based on the PDCCH monitoring gap extension described later (until the corresponding operation is indicated to be ended). Alternatively, the UE may periodically perform the corresponding operation (until the corresponding operation is indicated to be ended) or perform the corresponding operation only within a predetermined time (e.g., a predetermined time based on a timer). Alternatively, the corresponding operation may be terminated when an event condition for terminating the corresponding operation is met.

[0199] At least some of [Embodiment #1] to [Embodiment #4] described below may be selectively applied to the method proposed by the present disclosure. Each embodiment can be implemented in an independent form without being combined with other embodiments alone, or one or more embodiments can be implemented in a combined and associated form. As long as the principles of the present disclosure are maintained, some terms, symbols, sequences, etc. used to describe the present embodiment can be replaced with other terms, symbols, sequences, etc.

[0200] Hereinafter, although the present disclosure will be described by exemplifying an arbitrary structure for PDCCH monitoring gap extension and DCI transmission / reception in order to facilitate explanation of the principles of the embodiments, the proposed embodiments are not limited to a specific DCI transmission / reception type unless otherwise specified. Therefore, it is apparent that even if there is no additional description, as long as the principles of the embodiments are not violated, the embodiments proposed by the present invention can also be applied to the PDCCH monitoring gap extension operation according to DCI transmission / reception.

[0201] Now, an embodiment for extending the PDCCH monitoring gap according to the X slot value will be described.

[0202] 1. Example #1: Configuration of X-slot value

[0203] The embodiments of the present disclosure propose a technology for extending the PDCCH monitoring gap, so that the number of PDCCH monitoring times of the UE in the entire operation time of the UE can be reduced.

[0204] An X slot value for extending a PDCCH monitoring gap based on one slot in a legacy NR system to an X slot should be configured. For example, a candidate for the X slot value may be configured through RRC configuration of the UE and the BS. In this case, the candidate for the X slot value may be a natural number greater than 1.

[0205] If the request of the UE and / or the indication of the BS is performed through DCI (or UCI), the X slot value may be explicitly indicated.

[0206] Alternatively, when the operation of the present disclosure is based on a timer rather than a DCI, the X slot value may be set to a fixed value or to a preset value according to a specific condition. For example, the X slot value may be changed according to the SCS. For example, the X slot value may be a value pre-committed based on the current SCS of the UE.

[0207] Alternatively, the candidate for the X slot value may be a value that the UE notifies the BS through a capability report. In this case, the capability report may be sent through RRC signaling and / or UCI.

[0208] The UE may notify the BS of one or more X-slot values ​​based on various information such as current channel status and / or coverage level. The BS may select one of the one or more X-slot values ​​and indicate the selected X-slot value to the UE. Alternatively, the UE may notify the BS of one X-slot value.

[0209] The periodicity of the SS set in the current NR system can be configured as one of 1, 2, 4, 5, 8, 10, 16, 20, 20, 40, 80, 160, 320, 650, 1280, and 2560, which is a time slot unit. In this case, the X value can be configured to be aligned with the periodicity of the SS set. This is because when the periodicity of the SS set and the X time slot value are configured to be aligned with each other, the periodicity of the SS set can be easily changed according to the X time slot value. Alternatively, the X value can be set to a prime number so that the X time slot value is not aligned with the SS set.

[0210] If the X-slot values ​​are configured to align with the periodicity of SS sets, there may be situations where monitoring of a particular SS set is always excluded.

[0211] For example, if the X-slot value is configured to be aligned with the periodicity of the SS set and the priority of the SS set is determined in time order, the specific SS set may always be located in a time slot that is later in time among the X-slots due to the offset of the specific SS set because the periodicity of the specific SS set coincides with the X-slot value or has a multiple relationship with the X-slot value.

[0212] To prevent this, the timing of applying the SS set discard rule within the X time slot may be different. For example, the position of the time slot starting to apply the SS set discard rule may be different in each X time slot.

[0213] For example, the mod(n / X)th time slot in the nth X time slots may be selected as the starting time slot for applying the SS set discard rule.

[0214] 2. Embodiment #2: Periodicity of SS Sets Based on X Slot Values

[0215] One X time slot value may be configured so that the UE and the BS may share the X time slot value. For example, in [Embodiment #1], the BS may send a candidate for the X time slot value to the UE through RRC signaling, or the UE may send a candidate for the X time slot value to the BS through a capability report, and the BS may select one of the candidates for the X time slot value through DCI and / or MAC CE. Therefore, the UE and the BS may share one X time slot value. Alternatively, if the UE sends an X time slot value to the BS through a capability report according to [Embodiment #1], one X time slot value may be shared between the UE and the BS.

[0216] In this case, the BS may change the periodicity of the SS set according to an X-slot value.

[0217] For example, when X=2, the BS may double the periodicity of the SS set configured to the UE. In this case, for a common search space (CSS) configured for multiple UEs simultaneously, since it may be difficult to change the periodicity of the CSS set by focusing on only one UE, the periodicity of the CSS set may be maintained regardless of the X slot value as an exception to changing the periodicity of the SS set.

[0218] However, even in this case, the overlapping CSS can be excluded based on the SS set discard rule described later in [Embodiment #3]. Alternatively, the BS can configure the periodicity of the SS set for the UE so that the SS set discard rule can be easily applied in consideration of the PDCCH monitoring gap extension operation according to [Embodiment #1] to [Embodiment #4]. For example, if the BS configures a candidate for the X time slot value for the UE through RRC signaling, the BS can determine the periodicity of the SS set that can be aligned with the corresponding candidate for the X time slot value, and notify the UE of the determined periodicity of the SS set.

[0219] In such dynamic changes in the periodicity of the SS set, the UE may not be able to detect the BS's DCI transmission indicating the PDCCH monitoring gap extension operation, or a problem may occur at the time when the PDCCH monitoring gap extension operation is applied so that the periodicity of the SS set shared by the BS and the UE may not match.

[0220] In this case, since the UE has the capability to monitor the PDCCH within one time slot, the PDCCH monitoring gap may fall back from X time slots to one time slot again. For example, although the BS has changed the periodicity of the SS set based on the X time slot value, the UE may not be able to receive a signal (e.g., RRC signaling and / or DCI) indicating the changed periodicity of the SS set and perform PDCCH monitoring based on one time slot.

[0221] In this case, because the UE can determine whether the periodicity of the SS set has changed by checking the monitoring opportunity (MO) of the SS set, the UE can notify the BS that the periodicity of the SS set identified by the BS and the periodicity of the SS set identified by the UE do not match, or the UE can perform a PDCCH monitoring gap extension operation based on the periodicity of the checked SS set.

[0222] For example, the UE may monitor the PDCCH according to the periodicity of the SS set based on one time slot. If a pattern of not detecting the PDCCH at a specific interval continues for more than a specific time, the UE may recognize that the periodicity of the SS set has been changed according to the pattern, and notify the BS that the periodicity of the SS set has been changed or may perform a PDCCH monitoring gap extension operation based on the periodicity of the SS set according to the pattern.

[0223] 3. Example #3: SS set discard rules

[0224] The BS may operate such that the periodicity of the SS set is not changed according to the X slot value, or may not change the periodicity of the SS set. In this case, when the PDCCH monitoring gap of the UE is extended to the X slot value, the MO of the SS set for the ID overlapping in one X slot may be configured.

[0225] In this case, as the monitoring capability of the UE decreases, it is necessary to select the SS set to be monitored by the UE and discard the unselected SS set. Therefore, the rules for determining the SS set to be monitored and the SS set to be discarded can be configured by configuring the priority of the SS set. This is called the SS set discard rule.

[0226] Hereinafter, the aforementioned SS set dropping rule will be described.

[0227] [Option 1]

[0228] The UE may apply the SS set discard rule starting from the first slot among the X slots to determine the number of PDCCH candidates for the first slot, and may sequentially apply the remaining number of PDCCH candidates to the next slot.

[0229] For example, the monitoring capability of the UE may be based on a BD / CCE restriction, and the disclosed embodiment may be implemented in an application manner that distributes the BD / CCE restriction of one time slot in a conventional NR system to an X time slot. In this case, the UE calculates the number of PDCCH candidates or non-overlapping CCEs in the first time slot, which is the time slot that is the first in time within the X time slot. In addition, the BD / CCE restriction obtained by subtracting the number of PDCCH candidates or non-overlapping CCEs calculated for the first time slot from the maximum number of PDCCH candidates or non-overlapping CCEs is applied to the next second time slot to calculate the number of PDCCH candidates or non-overlapping CCEs. In this way, the SS set discard rule may be applied sequentially in time order within the X time slot. The SS set discard rule may be the same as that of the conventional NR system, or may be one of options 2, 3, and 4 described later. If one of options 2, 3, and 4 is applied, it may be assumed that the SS set discard rule is applied solely to the X time slot where X=1.

[0230] Alternatively, because the BS knows that X slots have been configured and performs PDCCH monitoring extension operation, the UE can apply the SS set drop rule starting from the second slot among the X slots under the assumption that the number of PDCCH candidates or non-overlapping CCEs is configured to always satisfy the BD / CCE restriction for the first slot in the X slots.

[0231] [Option 2]

[0232] With respect to the SS set with the same ID in the X time slot, the UE may configure the priority of the SS set that is ahead in time to be high.

[0233] Because the UE applies the BD / CCE restriction that is traditionally applied in one time slot to X time slots, the number of PDCCH candidates to be blindly decoded per time slot can be reduced. Therefore, it may be advantageous to avoid monitoring SS sets of overlapping IDs. Therefore, the UE can perform PDCCH monitoring by configuring the priority of SS sets based on time. For example, if X=2 and the MO of a particular SS set is located in the first and seventh symbols of the first time slot, and in the first and seventh symbols of the second time slot, the UE can monitor the SS set that is the earliest in time and is located in the first symbol of the first time slot, and may discard monitoring of the remaining SS sets with the same ID as the corresponding SS set.

[0234] That is, among the SS sets located in the seventh symbol of the first slot and the first and seventh symbols of the second slot, the UE may not monitor an SS set having the same ID as the corresponding SS set and may monitor an SS set having an ID different from the corresponding SS set.

[0235] Option 2 may have an advantage in terms of power saving of the UE. In the case of SS sets with the same ID, the probability that the PDCCH contains the same information is high. Therefore, considering the limited capabilities of the UE, repeated monitoring of the SS set with the same ID may be determined to be a waste of UE resources. According to Option 2, the number of PDCCH monitorings (i.e., the number of BDs) can be reduced while receiving as many DCIs of different information as possible, thereby achieving a power saving effect.

[0236] [Option 3]

[0237] The UE can configure the priority based on the ID of the SS set in the X time slot.

[0238] The UE may configure the priority of the ID of a specific SS set in the X time slot to be high, so that the UE may perform an operation so that the probability of the SS set of the corresponding ID being discarded during PDCCH monitoring is low. In other words, the UE may preferentially select an SS set with an ID having a high priority in all X time slots to fill the PDCCH candidates, and select the SS set of the next priority in sequence. In other words, the UE may determine the PDCCH candidates in the order of preferentially selecting an SS set with an ID having a high priority in all X time slots, excluding the SS set of the corresponding ID from the maximum number of PDCCH candidates, selecting an SS set with an ID having the next high priority, and excluding the SS set of the corresponding ID from the remaining number of PDCCH candidates.

[0239] In this case, even the SS set of the same ID can be monitored if its priority is high.

[0240] In option 3, the possibility of discarding monitoring of an important SS set (e.g., CSS) can be eliminated by configuring the priority of the important SS set (e.g., CSS) to be high. That is, the UE can determine the priority of the SS set in order of importance, perform BD based on the determined priority, and receive information through the corresponding SS set. In the previous option 2, if the SS set is always selected in time order, it may be difficult for the BS to perform PDCCH scheduling.

[0241] For example, it may be necessary that information transmitted to a UE should always be located in a symbol or slot that is temporally preceding within an X-slot. However, if the BS performs scheduling for multiple UEs simultaneously, scheduling problems may occur. Therefore, Option 3 has the advantage of facilitating BS scheduling.

[0242] [Option 4]

[0243] The priority may be configured according to the periodicity of the SS set. That is, the UE may determine the priority of the SS set considering the periodicity of the SS set.

[0244] For example, the UE can reduce the number of PDCCH monitoring times by configuring the priority of the SS set with short periodicity to be lower. In this case, the probability of monitoring the SS set with longer periodicity can be increased by infrequently monitoring the SS set with short periodicity to which more MOs can be allocated in the X time slot. In other words, the probability of monitoring multiple SS sets within the X time slot can be increased.

[0245] On the contrary, the priority of the SS set with short periodicity can be configured to be higher. When the periodicity of the SS set is shorter, it means that the PDCCH is sent more frequently through the corresponding SS set, and it can be determined that the BS schedules the corresponding SS set with a shorter periodicity in order to increase the probability of sending the PDCCH to the UE through the corresponding SS set. Therefore, the BS can make the UE frequently perform monitoring of the SS set with short periodicity, so that the UE can certainly monitor the information that should be necessary to send.

[0246] There may be rules that should always be configured when executing the aforementioned SS set discard rules. For example, in the CSS, the BD limit can be configured to exceed the limit in the method proposed in the present disclosure. The CSS has been designed to have high priority even in the SS set discard rules of the traditional NR system and is always monitored.

[0247] Therefore, if the SS set discard rule is applied to the CSS as proposed in the present disclosure, the probability of monitoring other SS sets can be reduced as much as the BD limit of the UE is reduced. Therefore, the SS set discard rule proposed in the present disclosure can be applied to SS sets other than the CSS, and the maximum value of the BD limit can be configured to be the same as that of the conventional NR system. For convenience, although the description is given based on the CSS, the important SS set that should always be monitored can be configured in the same manner as above.

[0248] For example, the BD / CCE limit of the CSS and the BD / CCE limit of the UE-specific search space (USS) may be configured separately. Assuming that the BD limit applicable to the X time slot is 44, the number of BDs corresponding to the predetermined ratio limited by the BS may be required for CSS monitoring. Here, the aforementioned predetermined ratio may vary depending on the situation and may be a preconfigured value or a predetermined fixed value.

[0249] Alternatively, the BD / CCE restriction of the conventional NR system may be applied only to the USS. For example, assuming that the BD limit applicable to the X slot is 44, BD may be performed for CSS monitoring without restriction, and the BD limit of 44 may be used only for USS monitoring. That is, the BD restriction is only for the USS and is not applied to the CSS, and all assigned CSSs may be monitored.

[0250] For example, a SS set drop rule may only apply to the USS, and may not be applied to the CSS.

[0251] Through the above method, CSS monitoring can be configured to always be executed first.

[0252] The UE may be operated to prioritize monitoring of the time slot in which the CSS is included. In other words, the SS set discard rule may be preferentially applied to the time slot in which the CSS is transmitted in the X time slot, and may be sequentially applied to the remaining time slots. For example, when X=4, if there is no CSS in the X time slot, the SS set discard rule may be applied to the time slots sequentially starting from the first time slot. On the contrary, when the CSS appears in the third time slot, the SS set discard rule may be preferentially applied to the third time slot and then the SS set discard rule for the remaining BD limit may be applied to the time slots starting from the first time slot or the fourth time slot which is the next time slot after the third time slot.

[0253] The UE can flexibly change the monitoring capacity according to the scheduling and business conditions. For example, when the business continues to determine that a large amount of PDCCH monitoring is required even if a DB limit of one time slot is applied to the X time slot, the DB limit applied to the X time slot can be increased to a BD limit of 2 time slots, a BD limit of 3 time slots, etc. in sequence. For example, when X=4 and BD limit=44, if there are already many PDCCHs that have not been monitored due to the SS set discard rule of the first time slot in the X time slot, the BD limit based on the business in the second time slot may be increased to 88. In other words, if the number of SS sets that can perform PDCCH monitoring in the first time slot due to the SS set discard rule is less than a specific number, the BD limit can be increased in the second time slot or from the second time slot and the BD limit to be increased can be based on the business.

[0254] If the BD / CCE restriction does not cause any problem even when the UE applies the SS set discard rule to all X slots, the SS set of the same ID may be monitored. For example, if the DB times and CCE numbers based on all allocated SS sets in X slots do not exceed the BD / CCE restriction, the UE may perform monitoring discard rules on all SS sets without applying the SS set.

[0255] The above-mentioned SS set discard rules may vary depending on the characteristics of each manufacturer's UE. For example, whether the UE's monitoring and BD can be performed serially and / or in parallel, and how many times the UE's monitoring and BD can be performed in parallel and / or serially may vary depending on the capabilities of the UE. For example, the UE may report relevant characteristics (e.g., BD processing capabilities, etc.) to the BS through a capability transfer process. The BS may determine the SS set discard rules with reference to the reported capabilities of the UE. The actual operation of the UE according to the determined BD / CCE restrictions and the determined SS set discard rules may be based on the characteristics of each UE.

[0256] 4. Example #4: Y-slot window

[0257] When the X slot value increases, it is difficult to apply the BD limit of the conventional NR system to all X slots or monitor all X slots to apply the SS set drop rule, which may be a waste of resources. Therefore, a Y slot using at least one of the X slots as a window can be defined.

[0258] If Y time slots are configured for the UE, the above SS set discarding rules may not be applied to X time slots but to Y time slots. In other words, if Y time slots are configured, this may mean that all PDCCH MOs within X time slots but outside Y time slots are discarded.

[0259] For example, Fig.10 As shown in (a), if X=4, Y=2, and an MO of an SS set with a periodicity of one time slot (e.g., an MO of a USS set or an MO of a CSS set) is allocated to each time slot, the UE may apply the SS set discard rule only to the Y time slots, rather than all the X time slots. In other words, it can be understood that Fig.10 MO 2 and MO 3 in (a) are determined to be not monitored from the beginning without applying the SS set discard rule.

[0260] In the present disclosure, in order to help understanding, MOs outside the Y time slots within the X time slots that are not candidates for applying the SS set discard rule are defined as early discarded MOs. The above-mentioned SS set discard rule is applied to MO 0 and MO 1 included in the Y time slot, and if the corresponding MO is not discarded, monitoring can be performed on the corresponding MO. For example, the SS set discard rule of [Embodiment #3] can be applied to the first time slot and the second time slot. For example, for CSS, monitoring can be performed in all four time slots without being restricted by the SS set discard rule. On the contrary, for USS, monitoring of the SS set according to the SS set discard rule of [Embodiment #3] can be performed in the first and second time slots designated as the Y time slot, and monitoring of USS can be not performed in the third time slot and the fourth time slot.

[0261] In other words, if the SS set of the MO with a periodicity of one slot is a USS set, the UE may perform monitoring in the first slot and the second slot included in the Y slot by applying the SS set discard rule and may not perform monitoring of the SS set in the third slot and the fourth slot. On the contrary, if the SS set of the MO with a periodicity of one slot is a CSS set, the UE may apply the SS set discard rule to all four slots in the X slot, or may monitor the SS set without BD / CCE restriction.

[0262] If, for a UE configured with X and Y, the periodicity of a specific SS set is configured as a multiple of X and the SS set duration is configured within Y, the UE may apply the SS set discard rule to the corresponding SS set and perform monitoring of the corresponding SS set without an early discarded MO. That is, in order to prevent the MO of a specific SS set from being discarded early, the periodicity of the specific SS set may be configured as a multiple of X and the duration of the specific SS set may be configured within Y.

[0263] Like the X time slot, the Y time slot may be a fixed value according to a specific condition or may be a value based on the capability report of the UE. For example, the UE may report capability information of a pair expressed by the (X, Y) combination to the BS. If the UE reports multiple combinations of (X, Y) in the capability information to the BS, the BS may select any one of the multiple (X, Y) combinations and indicate the selected (X, Y) combination to the UE.

[0264] Alternatively, the Y time slot value can be sequentially changed according to the scheduling type. For example, although X=8 and Y=1 are initially configured, the UE may determine that more PDCCHs need to be monitored according to the scheduling situation while monitoring the PDCCH. In this case, the Y time slot value may be sequentially increased to Y=2 until Y=8, so that more PDCCHs can be monitored.

[0265] The Y time slot can be located in different X time slots. The simplest method for selecting the position of the Y time slot without any additional configuration is to place the Y time slot in the earliest Y time slot in the X time slots, such as Fig.10 As shown in (a).

[0266] Alternatively, by dividing the number of X slots by the number of Y slots using Ceil(X / Y), the positions of the Y slots may be sequentially changed in each X slot. Fig.11 As illustrated in , when X=4 and Y=2, the Y slots may be located in the first and second slots and the seventh and eighth slots in every 8 slots (ie, two X slots).

[0267] Alternatively, the starting time slot of the Y time slots may be selected sequentially. Fig.10 When X=4 and Y=2 as shown in FIG. 1 , in the first X time slot, the first time slot and the second time slot may be Y time slots ( Fig.10 (a)); in the second X time slot, the second and third time slots may be Y time slots ( Fig.10 (b)); in the third X time slot, the third and fourth time slots may be Y time slots ( Fig.10 (c)); and in the fourth X time slot, the fourth and first time slots may be Y time slots.

[0268] The starting time slot of the Y time slot can be configured by RRC signaling of the BS and / or DCI. For example, the position of the Y time slot can be configured for the UE by configuring an offset value through RRC signaling and / or DCI. The above offset value can represent the relative distance between the starting time slot of the X time slot and the starting time slot of the Y time slot in units of time slots, or the relative distance between the starting point of the subframe including the X time slot and the starting time slot of the Y time slot in units of time slots.

[0269] In addition, the starting position of the Y time slot may be explicitly indicated. For example, the BS may indicate which time slot in the X time slot is the starting time slot of the Y time slot through RRC signaling and / or DCI. Thus, the UE may obtain information about the starting time slot of the Y time slot.

[0270] As described above, if the Y time slot is configured at a different position within the X time slot, this can prevent the monitoring of a specific SS set from being always excluded. For example, assume that the X time slot is configured to align with the periodicity of the SS set, and the priority of the SS set is determined in time order. If the periodicity of the specific SS set coincides with the X time slot value or has a multiple relationship with the X time slot value, the specific SS set may always be located in a later time slot of the X time slot in time according to the offset of the SS. Then, a situation in which the specific SS set is always excluded from the monitoring of the UE according to the SS set discard rule may occur.

[0271] Therefore, if the Y slots can be configured at different positions within the X slots, the above-mentioned problematic situation can be prevented by sequentially selecting the positions of the Y slots within the X slots as described above.

[0272] The various descriptions, functions, processes, proposals, methods and / or operational flowcharts of the present disclosure described herein may be applied to, but not limited to, various fields requiring wireless communication / connectivity between devices (e.g., 5G).

[0273] More specific examples will be described below with reference to the accompanying drawings. In the following drawings / descriptions, similar reference numerals represent the same or corresponding hardware blocks, software blocks or functional blocks unless otherwise specified.

[0274] Fig.12 The diagram shows a communication system 1 applied to the present disclosure.

[0275] refer to Fig.12, the communication system 1 applied to the present disclosure includes a wireless device, a BS and a network. A wireless device is a device that performs communication using a radio access technology (RAT) (e.g., 5G NR (or new RAT) or LTE), also referred to as a communication / radio / 5G device. The wireless device may include, but is not limited to, a robot 100a, a vehicle 100b-1 and 100b-2, an extended reality (XR) device 100c, a handheld device 100d, a home appliance 100e, an IoT device 100f, an artificial intelligence (AI) device / server 400. For example, a vehicle may include a vehicle with a wireless communication function, an autonomous driving vehicle, and a vehicle capable of performing vehicle-to-vehicle (V2V) communication. Here, a vehicle may include an unmanned aerial vehicle (UAV) (e.g., a drone). XR devices may include augmented reality (AR) / virtual reality (VR) / mixed reality (MR) devices and may be implemented in the form of a head-mounted device (HMD), a head-up display (HUD) installed in a vehicle, a television (TV), a smartphone, a computer, a wearable device, a home appliance, a digital signage, a vehicle, a robot, and the like. Handheld devices may include smart phones, smart boards, wearable devices (e.g., smart watches or smart glasses), and computers (e.g., laptops). Home appliances may include televisions, refrigerators, washing machines, etc. IoT devices may include sensors, smart meters, etc. For example, the BS and the network may be implemented as wireless devices, and a specific wireless device 200a may serve as a BS / network node for other wireless devices.

[0276] The wireless devices 100a to 100f may be connected to the network 300 via the BS 200. AI technology may be applied to the wireless devices 100a to 100f, and the wireless devices 100a to 100f may be connected to the AI ​​server 400 via the network 300. The network 300 may be configured using a 3G network, a 4G (e.g., LTE) network, or a 5G (e.g., NR) network. Although the wireless devices 100a to 100f may communicate with each other via the BS 200 / network 300, the wireless devices 100a to 100f may perform direct communication (e.g., side link communication) with each other without the intervention of the BS / network. For example, the vehicles 100b-1 and 100b-2 may perform direct communication (e.g., V2V / vehicle-to-everything (V2X) communication). An IoT device (e.g., a sensor) may perform direct communication with other IoT devices (e.g., a sensor) or other wireless devices 100a to 100f.

[0277] Wireless communication / connection 150a, 150b, and 150c may be established between wireless devices 100a to 100f / BS 200 and between BSs 200. Here, wireless communication / connection may be established through various RATs (e.g., 5G NR) such as UL / DL communication 150a, sidelink communication 150b (or D2D communication), or inter-BS communication 150c (e.g., relay or integrated access backhaul (IAB). Wireless signals may be sent and received between wireless devices, between wireless devices and BSs, and between BSs through wireless communication / connection 150a, 150b, and 150c. For example, signals may be sent and received on various physical channels through wireless communication / connection 150a, 150b, and 150c. To this end, various configuration information configuration processes for sending / receiving wireless signals, various signal processing processes (e.g., channel coding / decoding, modulation / demodulation, and resource mapping / demapping), and at least a portion of a resource allocation process may be performed based on various suggestions of the present disclosure.

[0278] Fig.13 The diagram illustrates a wireless device suitable for use with the present disclosure.

[0279] refer to Fig.13 , the first wireless device 100 and the second wireless device 200 can transmit wireless signals through various RATs (e.g., LTE and NR). {The first wireless device 100 and the second wireless device 200} may correspond to Fig.12 {wireless device 100x and BS 200} and / or {wireless device 100x and wireless device 100x}.

[0280] The first wireless device 100 may include one or more processors 102 and one or more memories 104, and may further include one or more transceivers 106 and / or one or more antennas 108. The processor 102 may control the memory 104 and / or the transceiver 106, and may be configured to implement the descriptions, functions, processes, proposals, methods and / or operational flow charts disclosed in this document. For example, the processor 102 may process the information in the memory 104 to generate first information / signals, and then transmit a wireless signal including the first information / signals through the transceiver 106. The processor 102 may receive a wireless signal including second information / signals through the transceiver 106, and then store information obtained by processing the second information / signals in the memory 104. The memory 104 may be connected to the processor 102 and may store a plurality of pieces of information related to the operation of the processor 102. For example, the memory 104 may store software code including instructions for executing part or all of the processes controlled by the processor 102 or for executing the descriptions, functions, processes, proposals, methods and / or operational flow charts disclosed in this document. The processor 102 and the memory 104 may be part of a communication modem / circuit / chip designed to implement a RAT (e.g., LTE or NR). The transceiver 106 may be connected to the processor 102 and transmit and / or receive wireless signals through one or more 108. Each of the transceivers 106 may include a transmitter and / or a receiver. The transceiver 106 may be used interchangeably with a radio frequency (RF) unit. In the present disclosure, a wireless device may be a communication modem / circuit / chip.

[0281] Specifically, instructions and / or operations controlled by the processor 102 of the first wireless device 100 and stored in the memory 104 of the first wireless device 100 according to an embodiment of the present disclosure will now be described.

[0282] Although the following operations are described based on the control operations of the processor 102 in terms of the processor 102, software codes for performing such operations may be stored in the memory 104. For example, in the present disclosure, at least one memory 104 may store instructions or programs as a computer-readable storage medium. When the instructions or programs are executed, at least one processor operably connected to at least one memory may perform operations related to the following operations according to an embodiment or implementation of the present disclosure.

[0283] Specifically, the processor 102 may control the transceiver 106 to receive first information about the SS set and / or second information related to the PDCCH monitoring gap from the BS. In this case, the processor 102 may control the transceiver 106 to receive the first information and / or the second information through the RRC. The second information may include, for example, at least one of an X time slot value when the PDCCH monitoring gap is extended, a new SS set discard rule, a Y time slot value for applying the discard rule, and a periodicity of SS set monitoring for the extended PDCCH monitoring gap. The first information may include multiple pieces of information about the SS set. The second information may also include multiple pieces of information related to the PDCCH monitoring gap.

[0284] For example, the second information may include a plurality of X time slot values, an SS set discarding rule, a Y time slot value, and / or a periodicity of SS set monitoring for extending the PDCCH monitoring gap.

[0285] The details of this operation can be based on [Example #1] to [Example #4].

[0286] The processor 102 may control the transceiver 106 to transmit capability information for the PDCCH monitoring gap to the BS in order to extend the PDCCH monitoring gap. In this case, the processor 102 may control the transceiver 106 to transmit the capability information to the BS in the form of (X, Y) which is a combination of an X slot value and a Y slot value through RRC signaling and / or UCI. The details of this operation may be based on [Embodiment #4].

[0287] The processor 102 may control the transceiver 106 to receive third information related to the PDCCH monitoring gap from the BS. For example, if a plurality of pieces of information related to the PDCCH monitoring gap are included in the second information, any one of the plurality of pieces of information may be indicated by DCI or MAC CE.

[0288] The details of this operation can be based on [Example #1] to [Example #4].

[0289] When determining that it is necessary to require power saving or load reduction of the UE, the processor 102 may issue a request for such determination to the BS through the transceiver 106 .

[0290] If it is determined that there is no information / channel to be transmitted by the BS to the UE within a predetermined time although the processor 102 does not control the transceiver 106 to transmit the capability information, the third information may be indicated for power saving of the UE.

[0291] Only one of capability information transmission and third information reception may be performed. For example, if capability information transmission is performed, third information reception may be omitted, and if capability information transmission is omitted, third information reception may be performed. Alternatively, both capability information transmission and third information reception may be omitted according to an operation related to a timer described later.

[0292] However, it is apparent that the capability information transmission and the third information reception may be performed together. For example, if the processor 102 controls the transceiver 106 to transmit a plurality of (X, Y) combinations, the processor 102 may control the transceiver 106 to receive the third information including any one of the plurality of (X, Y) combinations from the BS.

[0293] When a timer related to data transmission (eg, a timer associated with a MAC timer or a DRX timer or configured separately) expires, it can be expected that the UE and the BS will perform an operation for extending the PDCCH monitoring gap even without a separate indication or request.

[0294] The above capability information transmission and / or BS indication may be initiated through DCI and / or UCI, and is not limited to a specific format. The above capability information transmission and / or BS indication may also be performed through MAC CE or RRC.

[0295] The above-mentioned UE capability information transmission, BS indication, and timer operation are called triggering.

[0296] The PDCCH monitoring gap may be extended after a predetermined time from the trigger. The predetermined time may be predefined, or the processor 102 may control the transceiver 106 to receive information about the predetermined time through RRC signaling and / or DCI. Thus, the PDCCH monitoring start timing caused by the extended PDCCH monitoring gap may be determined.

[0297] In order to indicate release / termination of UE operation based on PDCCH monitoring gap extension, the same method as any one of the methods for initiating UE operation based on PDCCH monitoring gap extension (eg, the above three triggering operations) may be used.

[0298] The processor 102 may control the transceiver 106 to receive the PDCCH from the BS based on the information about the SS set drop rule and / or the PDCCH monitoring gap based on the first information, the second information, and / or the third information.

[0299] The details of this operation can be based on [Example #1] to [Example #4].

[0300] The second wireless device 200 may include one or more processors 202 and one or more memories 204, and may further include one or more transceivers 206 and / or one or more antennas 208. The processor 202 may control the memory 204 and / or the transceiver 206, and may be configured to implement the descriptions, functions, processes, proposals, methods and / or operational flow charts disclosed in this document. For example, the processor 202 may process the information in the memory 204 to generate third information / signals, and then send a wireless signal including the third information / signals through the transceiver 206. The processor 202 may receive a wireless signal including fourth information / signals through the transceiver 106, and then store information obtained by processing the fourth information / signals in the memory 204. The memory 204 may be connected to the processor 202, and store various information related to the operation of the processor 202. For example, the memory 204 may store software code including instructions for executing part or all of the processes controlled by the processor 202 or for executing the descriptions, functions, processes, proposals, methods and / or operational flow charts disclosed in this document. The processor 202 and the memory 204 may be part of a communication modem / circuit / chip designed to implement a RAT (e.g., LTE or NR). The transceiver 206 may be connected to the processor 202 and send and / or receive wireless signals through one or more antennas 208. Each of the transceivers 206 may include a transmitter and / or a receiver. The transceiver 206 may be used interchangeably with an RF unit. In the present disclosure, a wireless device may be a communication modem / circuit / chip.

[0301] Specifically, instructions and / or operations controlled by the processor 102 of the second wireless device 200 and stored in the memory 104 of the second wireless device 200 according to an embodiment of the present disclosure will now be described.

[0302] Although the following operations are described based on the control operations of the processor 202 in the aspect of the processor 202, software codes for executing such operations may be stored in the memory 204. For example, in the present disclosure, at least one memory 204 may store instructions or programs as a computer-readable storage medium. When the instructions or programs are executed, at least one processor operably connected to at least one memory may perform operations related to the following operations according to an embodiment or implementation of the present disclosure.

[0303] Specifically, the processor 202 may control the transceiver 206 to send the first information about the SS set and / or the second information related to the PDCCH monitoring gap to the UE. In this case, the processor 202 may control the transceiver 206 to send the first information and / or the second information through the RRC. The second information may include, for example, at least one of the X time slot value when the PDCCH monitoring gap is extended, the new SS set discard rule, the Y time slot value for applying the discard rule, or the periodicity of the SS set monitoring for the extended PDCCH monitoring gap. The first information may include multiple pieces of information about the SS set. The second information may also include multiple pieces of information related to the PDCCH monitoring gap.

[0304] For example, the second information may include a plurality of X time slot values, an SS set discarding rule, a Y time slot value, and / or a periodicity of SS set monitoring for extending the PDCCH monitoring gap.

[0305] The details of this operation can be based on [Example #1] to [Example #4].

[0306] The processor 202 may control the transceiver 206 to receive capability information for the PDCCH monitoring gap from the UE in order to extend the PDCCH monitoring gap. In this case, the processor 202 may control the transceiver 206 to receive capability information from the UE in the form of (X, Y) which is a combination of an X slot value and a Y slot value through RRC signaling and / or UCI. The details of this operation may be based on [Embodiment #4].

[0307] The processor 202 may control the transceiver 206 to transmit the third information related to the PDCCH monitoring gap to the UE. For example, if multiple pieces of information related to the PDCCH monitoring gap are included in the second information, any one of the multiple pieces of information may be indicated by DCI or MAC CE.

[0308] The details of this operation can be based on [Example #1] to [Example #4].

[0309] When determining that it is necessary to request the UE to save power or reduce load, the processor 202 may receive such a request from the UE through the transceiver 206 .

[0310] If it is determined that there is no information / channel to be sent by the processor 202 to the UE within a predetermined time although the processor 202 does not control the transceiver 206 to receive the capability information, the third information may be indicated for power saving of the UE.

[0311] Only one of the capability information reception and the third information transmission may be performed. For example, if the capability information reception is performed, the third information transmission may be omitted, and if the capability information reception is omitted, the third information transmission may be performed. Alternatively, both the capability information reception and the third information reception transmission may be omitted according to the operation related to the timer described later.

[0312] However, it is apparent that the capability information reception and the third information transmission may be performed together. For example, if the processor 202 controls the transceiver 206 to receive a plurality of (X, Y) combinations, the processor 202 may control the transceiver 206 to send the third information including any one of the plurality of (X, Y) combinations to the UE.

[0313] When a timer related to data transmission (eg, a timer associated with a MAC timer or a DRX timer or configured separately) expires, it can be expected that the UE and the BS will perform an operation for extending the PDCCH monitoring gap even without a separate indication or request.

[0314] The capability information transmission and / or the indication of the processor 202 may be initiated through DCI and / or UCI, and is not limited to a specific format. The capability information transmission and / or the indication of the BS may also be performed through MAC CE or RRC.

[0315] The above-mentioned transmission of the UE capability information, the instruction of the processor 202, and the operation of the timer are referred to as triggering.

[0316] The PDCCH monitoring gap may be extended after a predetermined time from the trigger. The predetermined time may be predefined, or the processor 202 may control the transceiver 206 to send information about the predetermined time to the UE through RRC signaling and / or DCI. Thus, the PDCCH monitoring start timing caused by the extended PDCCH monitoring gap may be determined.

[0317] In order to indicate release / termination of UE operation based on PDCCH monitoring gap extension, the same method as any one of the methods for initiating UE operation based on PDCCH monitoring gap extension (eg, the above three triggering operations) may be used.

[0318] The processor 202 may control the transceiver 206 to transmit the PDCCH to the UE based on the information about the SS set dropping rule and / or the PDCCH monitoring gap based on the first information, the second information, and / or the third information.

[0319] The details of this operation can be based on [Example #1] to [Example #4].

[0320] Now, the hardware elements of the wireless devices 100 and 200 will be described in more detail. One or more protocol layers may be implemented by, but not limited to, one or more processors 102 and 202. For example, one or more processors 102 and 202 may implement one or more layers (e.g., functional layers such as physical (PHY), medium access control (MAC), radio link control (RLC), packet data convergence protocol (PDCP), RRC, and service data adaptation protocol (SDAP)). One or more processors 102 and 202 may generate one or more protocol data units (PDUs) and / or one or more service data units (SDUs) according to the descriptions, functions, processes, proposals, methods, and / or operational flow charts disclosed in this document. One or more processors 102 and 202 may generate messages, control information, data, or information according to the descriptions, functions, processes, proposals, methods, and / or operational flow charts disclosed in this document and provide the messages, control information, data, or information to one or more transceivers 106 and 206. The one or more processors 102 and 202 may generate a signal (e.g., a baseband signal) including a PDU, SDU, message, control information, data, or information according to the description, functions, procedures, proposals, methods, and / or operational flow charts disclosed in this document and provide the generated signal to the one or more transceivers 106 and 206. The one or more processors 102 and 202 may receive a signal (e.g., a baseband signal) from the one or more transceivers 106 and 206 and obtain the PDU, SDU, message, control information, data, or information according to the description, functions, procedures, proposals, methods, and / or operational flow charts disclosed in this document.

[0321] One or more processors 102 and 202 may be referred to as controllers, microcontrollers, microprocessors, or microcomputers. One or more processors 102 and 202 may be implemented by hardware, firmware, software, or a combination thereof. For example, one or more application specific integrated circuits (ASICs), one or more digital signal processors (DSPs), one or more digital signal processing devices (DSPDs), one or more programmable logic devices (PLDs), or one or more field programmable gate arrays (FPGAs) may be included in one or more processors 102 and 202. The descriptions, functions, processes, proposals, methods, and / or operational flowcharts disclosed in this document may be implemented using firmware or software, and the firmware or software may be configured to include modules, processes, or functions. Firmware or software configured to execute the descriptions, functions, processes, proposals, methods, and / or operational flowcharts disclosed in this document may be included in one or more processors 102 and 202, or may be stored in one or more memories 104 and executed by one or more processors 102 and 202. The descriptions, functions, processes, proposals, methods, and / or operational flowcharts disclosed in this document may be implemented using firmware or software in the form of code, instructions, and / or instruction sets.

[0322] One or more memories 104 and 204 may be connected to one or more processors 102 and 202 and store various types of data, signals, messages, information, programs, codes, instructions, and / or commands. One or more memories 104 and 204 may be configured to include read-only memory (ROM), random access memory (RAM), electrically erasable programmable read-only memory (EPROM), flash memory, hard drive, register, cash memory, computer-readable storage medium, and / or combinations thereof. One or more memories 104 and 204 may be located inside and / or outside of one or more processors 102 and 202. One or more memories 104 and 204 may be connected to one or more processors 102 and 202 via various technologies such as wired or wireless connections.

[0323] One or more transceivers 106 and 206 may send user data, control information, and / or wireless signals / channels mentioned in the methods and / or operational flow charts of this document to one or more other devices. One or more transceivers 106 and 206 may receive user data, control information, and / or wireless signals / channels mentioned in the description, descriptions, functions, processes, proposals, methods, and / or operational flow charts disclosed in this document from one or more other devices. For example, one or more transceivers 106 and 206 may be connected to one or more processors 102 and 202, and send and receive wireless signals. For example, one or more processors 102 and 202 may perform control so that one or more transceivers 106 and 206 send user data, control information, or wireless signals to one or more other devices. One or more processors 102 and 202 may perform control so that one or more transceivers 106 and 206 can receive user data, control information, or wireless signals from one or more other devices. One or more transceivers 106 and 206 may be connected to one or more antennas 108 and 208, and one or more transceivers 106 and 206 may be configured to send and receive user data, control information, and / or wireless signals / channels mentioned in the descriptions, functions, processes, and suggestions disclosed in this document through one or more antennas 108 and 208. In this document, one or more antennas may be multiple physical antennas or multiple logical antennas (e.g., antenna ports). One or more transceivers 106 and 206 may convert received wireless signals / channels, etc. from RF band signals to baseband signals so as to process received user data, control information, and wireless signals / channels using one or more processors 102 and 202. One or more transceivers 106 and 206 may convert user data, control information, wireless signals / channels processed using one or more processors 102 and 202 from baseband signals to RF band signals. To this end, one or more transceivers 106 and 206 may include (analog) oscillators and / or filters.

[0324] Fig.14 The diagram is applied to a vehicle or an autonomous vehicle of the present disclosure. The vehicle or the autonomous vehicle may be implemented as a mobile robot, a car, a train, a manned / unmanned aerial vehicle (AV), a ship, etc.

[0325] refer to Fig.14 The vehicle or autonomous driving vehicle 100 may include an antenna unit 108, a communication unit 110, a control unit 120, a driving unit 140a, a power supply unit 140b, a sensor unit 140c, and an autonomous driving unit 140d. The antenna unit 108 may be configured as a part of the communication unit 110.

[0326] The communication unit 110 may send and receive signals (e.g., data and control signals) to and from external devices such as other vehicles, BSs (e.g., gNBs and roadside units), and servers. The control unit 120 may perform various operations by controlling elements of the vehicle or autonomous driving vehicle 100. The control unit 120 may include an ECU. The drive unit 140a may enable the vehicle or autonomous driving vehicle 100 to drive on a road. The drive unit 140a may include an engine, a motor, a powertrain, wheels, brakes, a steering device, and the like. The power supply unit 140b may supply power to the vehicle or autonomous driving vehicle 100, and may include a wired / wireless charging circuit, a battery, and the like. The sensor unit 140c may acquire information about vehicle status information, surrounding environment information, user information, and the like. The sensor unit 140c may include an inertial measurement unit (IMU) sensor, a collision sensor, a wheel sensor, a speed sensor, a slope sensor, a weight sensor, a heading sensor, a position module, a vehicle forward / backward sensor, a battery sensor, a fuel sensor, a tire sensor, a steering sensor, a temperature sensor, a humidity sensor, an ultrasonic sensor, an illumination sensor, a pedal position sensor, etc. The autonomous driving unit 140d may implement a technology for maintaining a lane on which the vehicle is driving, a technology for automatically adjusting a speed such as an adaptive cruise control, a technology for autonomously driving along a determined path, a technology for driving by automatically setting a path if a destination is set, and the like.

[0327] For example, the communication unit 110 may receive map data, traffic information data, etc. from an external server. The autonomous driving unit 140d may generate an autonomous driving route and a driving plan from the acquired data. The control unit 120 may control the drive unit 140a so that the vehicle or the autonomous driving vehicle 100 may move along the autonomous driving route according to the driving plan (e.g., speed / direction control). During autonomous driving, the communication unit 110 may obtain the latest traffic information data from the external server irregularly / irregularly, and may obtain surrounding traffic information data from neighboring vehicles. During autonomous driving, the sensor unit 140c may obtain information about vehicle state information and / or surrounding environment information. The autonomous driving unit 140d may update the autonomous driving route and driving plan based on the newly acquired data / information. The communication unit 110 may transmit information about the vehicle position, autonomous driving route, and / or driving plan to an external server. The external server may predict traffic information data based on information collected from the vehicle or autonomous driving vehicle, using AI technology, etc., and provide the predicted traffic information data to the vehicle or autonomous driving vehicle.

[0328] The embodiments of the present disclosure described herein below are combinations of elements and features of the present disclosure. Unless otherwise stated, these elements or features may be considered as selective. Each element or feature may be practiced without being combined with other elements or features. In addition, the embodiments of the present disclosure may be constructed by combining a part of elements and / or features. The order of operations described in the embodiments of the present disclosure may be rearranged. Some constructions of any one embodiment may be included in another embodiment and may be replaced by the corresponding constructions of another embodiment. It will be apparent to those skilled in the art that claims that are not explicitly referenced to each other in the attached claims may be presented in combination as embodiments of the present disclosure, or may be included as new claims by subsequent amendments after submitting an application.

[0329] In the present disclosure, in some cases, a specific operation described as being performed by a BS may be performed by an upper node of the BS. That is, it is apparent that in a network consisting of a plurality of network nodes including a BS, various operations performed for communication with an MS may be performed by the BS or network nodes other than the BS. The term "BS" may be replaced with the term "fixed station", "Node B", "enhanced Node B (eNodeB or eNB)", "access point", etc.

[0330] Those skilled in the art will appreciate that the present disclosure can be performed in other specific ways different from the ways set forth herein without departing from the spirit and essential characteristics of the present disclosure. Therefore, the above embodiments are interpreted in all respects as illustrative and not restrictive. The scope of the present disclosure should be determined by the appended claims and their legal equivalents, rather than by the above description, and all changes falling within the meaning and equivalent range of the appended claims should be included therein.

[0331] Industrial Applicability

[0332] Although the above-mentioned method of transmitting and receiving a DL control channel and the apparatus thereof have been described based on an example applied to a 5G NR system, the method and apparatus are applicable to various wireless communication systems in addition to the 5G NR system.

Claims

1. A method for receiving a physical downlink control channel (PDCCH) by a user equipment (UE) in a wireless communication system, the method comprising: transmitting capability information associated with a first number of X time slots and a second number of at least one Y time slot; as well as receiving a first PDCCH in the at least one Y time slot through a UE-specific SS (USS) set based on the capability information, wherein the at least one Y time slot is included in the X time slot, and X and Y are positive integers, The monitoring period of the USS set is an integer multiple of the length of the X time slot.

2. The method according to claim 1, wherein: A second PDCCH is received through a common SS (CSS) set in the X slot.

3. The method according to claim 2, wherein: The CSS set to be monitored in the Y time slot is determined to have a higher priority than the USS set to be monitored in the Y time slot.

4. The method according to claim 1, wherein: The capability information is expressed as (X, Y) which is a combination of the number of the X time slots and the number of the at least one Y time slot.

5. The method according to claim 1, wherein: The X time slots are consecutive and the at least one Y time slot is consecutive.

6. The method according to claim 1, wherein: A start time slot of the at least one Y time slot is not aligned with a start time slot of the X time slots.

7. A user equipment (UE), the user equipment (UE) being configured to receive a physical downlink control channel (PDCCH) in a wireless communication system, the UE comprising: at least one transceiver; at least one processor; as well as at least one memory operably connected to the at least one processor and configured to store instructions that, when executed, cause the at least one processor to perform operations comprising: transmitting, by the at least one transceiver, capability information associated with a first number of X time slots and at least one second number of Y time slots, and receiving, by the at least one transceiver, a first PDCCH in the at least one Y time slot using a UE-specific SS (USS) set based on the capability information, and wherein the at least one Y time slot is included in the X time slot, and X and Y are positive integers, The monitoring period of the USS set is an integer multiple of the length of the X time slot.

8. The UE according to claim 7, wherein: A second PDCCH is received through a common SS (CSS) set in the X slot.

9. The UE according to claim 8, wherein: The CSS set to be monitored in the Y time slot is determined to have a higher priority than the USS set to be monitored in the Y time slot.

10. The UE according to claim 7, wherein: The capability information is expressed as (X, Y) which is a combination of the number of the X time slots and the number of the at least one Y time slot.

11. The UE according to claim 7, wherein: The X time slots are consecutive and the at least one Y time slot is consecutive.

12. The UE according to claim 7, wherein: A start time slot of the at least one Y time slot is not aligned with a start time slot of the X time slots.

13. An apparatus for receiving a physical downlink control channel (PDCCH) through a search space (SS) set in a wireless communication system, the apparatus comprising: at least one processor; as well as at least one memory operably connected to the at least one processor and configured to store instructions that, when executed, cause the at least one processor to perform operations comprising: transmitting capability information associated with a first number of X time slots and a second number of at least one Y time slot, and Based on the information, receiving the PDCCH via a UE-specific SS (USS) set in the at least one Y time slot, and wherein the at least one Y time slot is included in the X time slot, and X and Y are positive integers, The monitoring period of the USS set is an integer multiple of the length of the X time slot.

14. A computer-readable storage medium comprising at least one computer program, the at least one computer program causing at least one processor to perform operations comprising: transmitting capability information associated with a first number of X time slots and a second number of at least one Y time slot, and receiving a physical downlink control channel (PDCCH) via a UE-specific search space (USS) set in the at least one Y time slot based on the capability information, and wherein the at least one Y time slot is included in the X time slot, and X and Y are positive integers, The monitoring period of the USS set is an integer multiple of the length of the X time slot.

15. A method for transmitting a physical downlink control channel (PDCCH) by a base station (BS) through a search space (SS) set in a wireless communication system, the method comprising: receiving capability information associated with a first number of X time slots and a second number of at least one Y time slot, and Based on the capability information, transmitting the PDCCH via a UE-specific SS (USS) set in the at least one Y time slot, and wherein the at least one Y time slot is included in the X time slot, and X and Y are positive integers, The monitoring period of the USS set is an integer multiple of the length of the X time slot.

16. A base station (BS), the base station (BS) being configured to transmit a physical downlink control channel (PDCCH) through a search space (SS) set in a wireless communication system, the BS comprising: at least one transceiver; at least one processor; as well as at least one memory operably connected to the at least one processor and configured to store instructions that, when executed, cause the at least one processor to perform operations comprising: receiving, by the at least one transceiver, capability information associated with a first number of X time slots and at least a second number of Y time slots, and Based on the capability information, transmitting, by the at least one transceiver, a PDCCH in the at least one Y time slot using a UE-specific SS (USS) set, and wherein the at least one Y time slot is included in the X time slot, and X and Y are positive integers, The monitoring period of the USS set is an integer multiple of the length of the X time slot.

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