Operation method of terminal and device using same method in wireless communication system

Abstract

An operation method of a terminal and a device in a wireless communication system are provided. The terminal accesses a base station through a random access process, receives, from the base station, a message for configuring a monitoring occasion of a downlink control channel, receives a pre-sync signal from the base station before the monitoring occasion, and performs synchronization on the basis of the pre-sync signal, wherein the pre-sync signal is a signal in which a first time domain signal generated on the basis of a CAZAC sequence and a second time domain signal generated on the basis of a complex conjugate of the CAZAC sequence are arranged within a predetermined time interval.

Description

Method of operation of a terminal in a wireless communication system and a device using the method

[0001] The present disclosure relates to a method of operation of a terminal in a wireless communication system and a device using said method.

[0002] As more communication devices require larger communication capacities, the need for enhanced mobile broadband communication compared to existing radio access technology (RAT) is emerging. Furthermore, massive Machine Type Communications (MTC), which connects multiple devices and objects to provide various services anytime and anywhere, is also one of the major issues to be considered in next-generation communication. In addition, communication system designs that consider services / terminals sensitive to reliability and latency are being discussed. Thus, the introduction of next-generation radio access technologies that consider enhanced mobile broadband (eMBB), massive MTC, and Ultra-Reliable and Low Latency Communication (URLC) is being discussed, and for convenience in this disclosure, such technology is referred to as new RAT or NR. NR is also referred to as a fifth-generation (5G) system.

[0003] As the performance and functionality of a terminal improve, such as display resolution, display size, processor, memory, and the increase in applications, power consumption also increases. Since the power supply to a terminal may be limited by the battery, it is important to reduce power consumption. This is also true for terminals operating in NR.

[0004] One example of a method to reduce power consumption in a terminal is the discontinuous reception (DRX) operation. A terminal may need to monitor the PDCCH for every subframe to determine whether there is data to receive. However, since the terminal does not always receive data in every subframe, such operation results in significant unnecessary battery consumption. DRX is an operation designed to reduce this battery consumption. For example, the terminal wakes up during a DRX cycle and monitors the control channel (e.g., physical downlink control channel: PDCCH) for a set period (DRX on duration). If no PDCCH is detected during this period, it enters a sleeping mode, for example, a state in which the RF (radio frequency) transceiver is turned off. If a PDCCH is detected during this period (DRX on duration), the PDCCH monitoring time is extended, and data transmission and reception can be performed according to the detected PDCCH.

[0005] Meanwhile, additional power consumption reduction methods may be introduced for such DRX operations. For example, it may be unnecessary or inefficient for the terminal to wake up and monitor the PDCCH at every DRX cycle. To this end, the network may provide the terminal with a signal containing information regarding whether to wake up before the start of the DRX cycle (this may be referred to as a wake-up signal: WUS, for example, DCI (downlink control information) format 2_6 may correspond to this). The terminal may monitor the WUS at WUS monitoring occasions within a configured WUS monitoring window. Based on the detected WUS, the terminal may perform the instructed operation during the DRX cycle.

[0006] Meanwhile, for example, in a non-terrestrial network, as the sleep period of a terminal becomes longer, the time / frequency difference between the base station and the terminal may increase due to the inability to measure the mobility and channel conditions of the terminal occurring during the sleep period, and the inability to perform channel tracking.

[0007] Consequently, the time / frequency synchronization performance may be reduced due to the aforementioned sleep period. In this case, the terminal must achieve synchronization based on SSBs (Synchronization Signal Blocks); to do so, it must wake up tens of milliseconds (ms) prior to receiving an SSB, and since synchronization must be achieved using multiple SSBs when the received SINR (Signal-to-Interference plus Noise Ratio) of the SSB is low, power saving efficiency is reduced.

[0008] The technical problem that the present disclosure aims to solve is to provide a method of operation of a terminal in a wireless communication system and a device utilizing said method.

[0009] In one aspect, a method of operation of a terminal is provided. The method is characterized in that the terminal connects to a base station through a random access process, the terminal receives a message from the base station setting an occasion for monitoring a downlink control channel, the terminal receives a pre-sync signal from the base station prior to the occasion for monitoring, and the terminal performs synchronization based on the pre-sync signal, wherein the pre-sync signal is a signal in which a first time domain signal generated based on a constant amplitude zero autocorrelation (CAZAC) sequence and a second time domain signal generated based on the complex conjugate of the CAZAC sequence are arranged within a certain time interval.

[0010] In another aspect, a terminal, device, or computer-readable storage medium is provided for executing the above method.

[0011] In another aspect, a method of operation of a base station is provided. The method is characterized in that the base station connects with a terminal through a random access process, the base station transmits a message to the terminal to set an occasion for monitoring a downlink control channel, and the base station transmits a pre-sync signal to the terminal for synchronization with the terminal prior to the occasion for monitoring, wherein the pre-sync signal is a signal in which a first time domain signal generated based on a constant amplitude zero autocorrelation (CAZAC) sequence and a second time domain signal generated based on the complex conjugate of the CAZAC sequence are placed within a certain time interval.

[0012] In another aspect, a base station utilizing the operation method of the above base station is provided.

[0013] According to the method of the present disclosure, the terminal can perform accurate synchronization using a short period of time, so it can remain in a deep sleep state / mode for the longest possible time, thereby increasing the power saving effect.

[0014] The effects obtainable from the embodiments of the present disclosure are not limited to those mentioned above, and other unmentioned effects can be clearly derived and understood by those skilled in the art to which the technical configuration of the present disclosure applies from the description of the embodiments of the present disclosure below. That is, unintended effects resulting from implementing the configuration described in the present disclosure can also be derived by those skilled in the art from the embodiments of the present disclosure.

[0015] FIG. 1 illustrates a wireless communication system to which the present disclosure may be applied.

[0016] Figure 2 is a block diagram showing the radio protocol architecture for the user plane.

[0017] Figure 3 is a block diagram showing the wireless protocol structure for the control plane.

[0018] Figure 4 illustrates the system structure of a New Generation Radio Access Network (NG-RAN) to which NR is applied.

[0019] Figure 5 illustrates the functional partitioning between NG-RAN and 5GC.

[0020] Figure 6 illustrates a frame structure that can be applied in NR.

[0021] Figure 7 illustrates a slot structure.

[0022] Figure 8 illustrates a core set.

[0023] Figure 9 is a diagram showing the difference between the core set in the conventional control area and NR.

[0024] Figure 10 illustrates an example of a frame structure for a new wireless access technology.

[0025] Figure 11 illustrates the structure of a self-contained slot.

[0026] FIG. 12 illustrates physical channels and general signal transmission.

[0027] Figure 13 illustrates a scenario in which three different bandwidth parts are set.

[0028] Figure 14 illustrates a DRX cycle.

[0029] Fig. 15 illustrates the operation of DRX.

[0030] Figure 16 schematically illustrates the power consumption of the UE occurring during the sleep period.

[0031] Figure 17 shows the energy consumption profile of a terminal operating in various states under various traffic conditions over 24 hours.

[0032] Figure 18 shows an example of reducing the number of PDCCH monitoring cycles by indicating whether to wake up in the upcoming on period through the DCI prior to the DRX on period.

[0033] FIG. 19 illustrates an operation related to a paging early indication (PEI) DCI.

[0034] Figure 20 illustrates the process of generating a pre-sync signal.

[0035] Figure 21 shows the state change over time of the proposed technique and the change in power consumption accordingly when the wake-up instruction is not set in DRX mode.

[0036] Figure 22 shows the state change over time of the proposed technique and the change in power consumption accordingly when a wake-up instruction is set in DRX mode.

[0037] FIG. 23 illustrates a method of operation of a terminal.

[0038] FIG. 24 illustrates the signaling process and operation between a network (base station) and a terminal.

[0039] FIG. 25 illustrates a wireless device that can be applied to the present specification.

[0040] Figure 26 illustrates an example of a signal processing module structure.

[0041] Figure 27 illustrates another example of a signal processing module structure within a transmission device.

[0042] FIG. 28 illustrates an example of a wireless communication device according to an embodiment of the present disclosure.

[0043] Figure 29 illustrates another example of a wireless device.

[0044] FIG. 30 illustrates a communication system (1) applicable to the present specification.

[0045] The symbols / abbreviations / terms used in this specification are as follows.

[0046] AGC: Automatic Gain Control

[0047] CAZAC: Constant Amplitude Zero Autocorrelation

[0048] CFO: Central Frequency Offset

[0049] CRS: Cell specific reference signal

[0050] CSI: Channel state information

[0051] CSI-RS: Channel state information reference signal

[0052] DCI: Downlink Control Information

[0053] DRX: Discontinuous Reception

[0054] FEC: Forward Error Correction

[0055] FFT: Fast Fourier Transform

[0056] IFFT: Inverse Fast Fourier Transform

[0057] LTE: Long-Term Evolution

[0058] MCS: Modulation coding scheme

[0059] NR: New Radio

[0060] NTN: Non-terrestrial network

[0061] OFDM: Orthogonal Frequency Division Multiplexing

[0062] PEI: Paging Early Indication

[0063] PDCCH: Physical downlink control channel

[0064] PSS: Primary Synchronization Signal

[0065] RRC: Radio Resource Control

[0066] SINR: Signal-to-Interference plus Noise Ratio

[0067] SSB: Synchronization Signal Block

[0068] UE: User equipment

[0069] FIG. 1 illustrates a wireless communication system to which the present disclosure may be applied. This may also be referred to as an E-UTRAN (Evolved-UMTS Terrestrial Radio Access Network) or an LTE (Long Term Evolution) / LTE-A system.

[0070] E-UTRAN includes a base station (20: Base Station, BS) that provides a control plane and a user plane to a terminal (10: User Equipment, UE). The terminal (10) may be fixed or mobile and may be referred to by other terms such as MS (Mobile station), UT (User Terminal), SS (Subscriber Station), MT (mobile terminal), Wireless Device, or terminal. The base station (20) refers to a fixed station that communicates with the terminal (10) and may be referred to by other terms such as eNB (evolved-NodeB), BTS (Base Transceiver System), Access Point, or gNB.

[0071] Base stations (20) can be connected to each other through an X2 interface. The base station (20) is connected to the EPC (Evolved Packet Core, 30) through the S1 interface, more specifically to the MME (Mobility Management Entity) through the S1-MME and to the S-GW (Serving Gateway) through the S1-U.

[0072] The EPC (30) consists of an MME, an S-GW, and a P-GW (Packet Data Network-Gateway). The MME holds information regarding the terminal's connection information or capabilities, and this information is primarily used for managing the terminal's mobility. The S-GW is a gateway with an E-UTRAN as its endpoint, and the P-GW is a gateway with a PDN as its endpoint.

[0073] The layers of the Radio Interface Protocol between a terminal and a network can be classified into L1 (Layer 1), L2 (Layer 2), and L3 (Layer 3) based on the lower three layers of the Open System Interconnection (OSI) model, which is widely known in communication systems. Among these, the physical layer, which belongs to Layer 1, provides information transfer services using a physical channel, while the Radio Resource Control (RRC) layer, located at Layer 3, performs the role of controlling radio resources between the terminal and the network. To this end, the RRC layer exchanges RRC messages between the terminal and the base station.

[0074] FIG. 2 is a block diagram showing the radio protocol architecture for the user plane. FIG. 3 is a block diagram showing the radio protocol architecture for the control plane. The user plane is a protocol stack for transmitting user data, and the control plane is a protocol stack for transmitting control signals.

[0075] Referring to Figures 2 and 3, the physical layer (PHY layer) provides information transfer services to upper layers using a physical channel. The physical layer is connected to the upper layer, the MAC (Medium Access Control) layer, through a transport channel. Data travels between the MAC layer and the physical layer through the transport channel. Transport channels are classified according to how and with what characteristics data is transmitted through a wireless interface.

[0076] Data travels between different physical layers, specifically between the physical layers of the transmitter and the receiver, through a physical channel. This physical channel can be modulated using the Orthogonal Frequency Division Multiplexing (OFDM) method and utilizes time and frequency as wireless resources.

[0077] The functions of the MAC layer include mapping between logical channels and transport channels, and multiplexing / demultiplexing MAC SDUs (service data units) belonging to logical channels into transport blocks provided to physical channels over the transport channel. The MAC layer provides services to the RLC (Radio Link Control) layer through logical channels.

[0078] The functions of the RLC layer include the concatenation, segmentation, and reassembly of RLC SDUs. To ensure the various Quality of Service (QoS) required by Radio Bearers (RBs), the RLC layer provides three operating modes: Transparent Mode (TM), Unacknowledged Mode (UM), and Acknowledged Mode (AM). AM RLC provides error correction through Automatic Repeat Requests (ARQ).

[0079] The RRC (Radio Resource Control) layer is defined only in the control plane. The RRC layer is responsible for controlling logical channels, transmission channels, and physical channels in relation to the configuration, reconfiguration, and release of wireless bearers. RB refers to a logical path provided by the first layer (PHY layer) and the second layer (MAC layer, RLC layer, PDCP layer) for data transmission between a terminal and a network.

[0080] The functions of the PDCP (Packet Data Convergence Protocol) layer in the user plane include the delivery of user data, header compression, and ciphering. The functions of the PDCP (Packet Data Convergence Protocol) layer in the control plane include the delivery of control plane data and encryption / integrity protection.

[0081] The establishment of an RB refers to the process of defining the characteristics of the wireless protocol layer and channel to provide specific services, and setting their respective specific parameters and operating methods. RBs can be further divided into two types: SRBs (Signaling RBs) and DRBs (Data RBs). SRBs are used as a channel for transmitting RRC messages in the control plane, while DRBs are used as a channel for transmitting user data in the user plane.

[0082] When an RRC connection is established between the terminal's RRC layer and the E-UTRAN's RRC layer, the terminal is in an RRC connected state; otherwise, it is in an RRC idle state.

[0083] Downlink transmission channels for transmitting data from a network to a terminal include a Broadcast Channel (BCH) for transmitting system information and a Shared Channel (SCH) for transmitting user traffic or control messages. Traffic or control messages for downlink multicast or broadcast services may be transmitted via the Shared Channel (SCH) or via a separate Multicast Channel (MCH). Meanwhile, uplink transmission channels for transmitting data from a terminal to a network include a Random Access Channel (RACH) for transmitting initial control messages and a Shared Channel (SCH) for transmitting user traffic or control messages.

[0084] Logical channels that are above the transmission channel and map to the transmission channel include BCCH (Broadcast Control Channel), PCCH (Paging Control Channel), CCCH (Common Control Channel), MCCH (Multicast Control Channel), and MTCH (Multicast Traffic Channel).

[0085] A physical channel consists of multiple OFDM symbols in the time domain and multiple subcarriers in the frequency domain. A single subframe consists of multiple OFDM symbols in the time domain. A resource block is a resource allocation unit composed of multiple OFDM symbols and multiple subcarriers. Additionally, each subframe may utilize specific subcarriers of specific OFDM symbols (e.g., the first OFDM symbol) within that subframe for a Physical Downlink Control Channel (PDCCH), e.g., an L1 / L2 control channel. The Transmission Time Interval (TTI) is the unit time for subframe transmission.

[0086] The following describes new radio access technology (new RAT, NR).

[0087] As more communication devices require larger communication capacities, the need for enhanced mobile broadband communication compared to existing radio access technology (RAT) is emerging. Furthermore, Massive Machine Type Communications (MTC), which connects multiple devices and objects to provide various services anytime and anywhere, is also one of the major issues to be considered in next-generation communication. In addition, communication system designs that take into account services and terminals sensitive to reliability and latency are being discussed. Thus, the introduction of next-generation radio access technologies that consider enhanced mobile broadband communication, massive MTC, and Ultra-Reliable and Low Latency Communication (URLC) is being discussed, and for convenience, this technology is referred to as new RAT or NR in this disclosure.

[0088] Figure 4 illustrates the system structure of a New Generation Radio Access Network (NG-RAN) to which NR is applied.

[0089] Referring to FIG. 4, the NG-RAN may include gNBs and / or eNBs that provide user plane and control plane protocol termination to terminals. FIG. 4 illustrates a case where only gNBs are included. The gNBs and eNBs are connected to each other via Xn interfaces. The gNBs and eNBs are connected to the 5G Core Network (5GC) via NG interfaces. More specifically, they are connected to the access and mobility management function (AMF) via NG-C interfaces and to the user plane function (UPF) via NG-U interfaces.

[0090] Figure 5 illustrates the functional partitioning between NG-RAN and 5GC.

[0091] Referring to FIG. 5, the gNB can provide functions such as Inter Cell RRM, RB control, Connection Mobility Control, Radio Admission Control, Measurement Configuration & Provision, and Dynamic Resource Allocation. The AMF can provide functions such as NAS security and idle state mobility processing. The UPF can provide functions such as Mobility Anchoring and PDU processing. The SMF (Session Management Function) can provide functions such as terminal IP address allocation and PDU session control.

[0092] Figure 6 illustrates a frame structure that can be applied in NR.

[0093] Referring to FIG. 6, radio frames (hereinafter abbreviated as frames) may be used for uplink and downlink transmission in NR. A frame has a length of 10 ms and can be defined as two 5 ms half-frames (HF). A half-frame can be defined as five 1 ms subframes (SF). A subframe can be divided into one or more slots, and the number of slots within a subframe depends on the subcarrier spacing (SCS). Each slot contains 12 or 14 OFDM(A) symbols according to the cyclic prefix (CP). When a normal CP is used, each slot contains 14 symbols. When an extended CP is used, each slot contains 12 symbols. Here, the symbols may include OFDM symbols (or CP-OFDM symbols) or SC-FDMA symbols (or DFT-s-OFDM symbols).

[0094] The following Table 1 shows examples of subcarrier spacing configurations μ.

[0095] [Table 1]

[0096]

[0097] Table 2 below shows the number of slots (N) within a frame according to the subcarrier spacing configuration μ. frame,μ slot ), number of slots in the subframe (N subframe,μ slot ), number of symbols in the slot (N slot symb Examples include ) etc.

[0098] [Table 2]

[0099]

[0100] Figure 6 illustrates μ=0, 1, 2, and 3.

[0101] Table 2-1 below illustrates how the number of symbols per slot, the number of slots per frame, and the number of slots per subframe vary depending on the SCS when an extended CP is used (μ= 2, 60KHz).

[0102] [Table 2-1]

[0103]

[0104] In an NR system, OFDM(A) numerology (e.g., SCS, CP length, etc.) can be configured differently among multiple cells merged into a single terminal. Accordingly, the (absolute time) interval of a time resource (e.g., SF, slot, or TTI) (collectively referred to as TU (Time Unit) for convenience) composed of the same number of symbols can be configured differently among the merged cells.

[0105] Figure 7 illustrates a slot structure.

[0106] A slot may contain multiple symbols in the time domain. For example, in the case of a normal CP, one slot may contain 14 symbols (or 7 symbols), but in the case of an extended CP, one slot may contain 12 symbols (or 6 symbols). A carrier may contain multiple subcarriers in the frequency domain. A Resource Block (RB) may be defined as multiple (e.g., 12) consecutive subcarriers in the frequency domain. A Bandwidth Part (BWP) may be defined as multiple consecutive (P)RBs in the frequency domain and may correspond to a single numerology (e.g., SCS, CP length, etc.). A carrier may contain up to N (e.g., 4 or 5) BWPs. Data communication is performed through the active BWP, and only one BWP may be active for a single terminal. In a resource grid, each element is referred to as a Resource Element (RE), and a single complex symbol can be mapped to it. A mini-slot can consist of, for example, 2, 4, or 7 symbols.

[0107] The PDCCH (physical downlink control channel) can be composed of one or more CCEs (control channel elements) as shown in Table 3 below.

[0108] [Table 3]

[0109]

[0110] For example, a PDCCH can be transmitted through a resource consisting of 1, 2, 4, 8, or 16 CCEs. Here, a CCE consists of 6 REGs (resource element groups), and one REG consists of one resource block in the frequency domain and one OFDM (orthogonal frequency division multiplexing) symbol in the time domain.

[0111] Monitoring means decoding each PDCCH candidate according to the DCI (downlink control information) format. The terminal monitors a set of PDCCH candidates in one or more core sets (CORESET, described below) on the active DL BWP of each active serving cell where PDCCH monitoring is configured, according to the corresponding set of search spaces.

[0112] In NR, a new unit called a control resource set (CORESET) can be introduced. A terminal can receive PDCCH from the core set.

[0113] Figure 8 illustrates a core set.

[0114] Referring to Fig. 8, the core set is N in the frequency domain. CORESET RB It consists of N resource blocks, and in the time domain N CORESET symb ∈ Can be composed of {1, 2, 3} symbols. N CORESET RB , N CORESET symbIt can be provided by the base station through an upper layer signal. As illustrated in FIG. 8, a core set may include a plurality of CCEs (or REGs). A single CCE may be composed of a plurality of REGs (resource element groups), and a single REG may include one OFDM symbol in the time domain and 12 resource elements in the frequency domain.

[0115] The terminal can attempt to detect PDCCH in units of 1, 2, 4, 8, or 16 CCEs within the core set. One or more CCEs that can attempt to detect PDCCH may be called PDCCH candidates.

[0116] The terminal can be configured with multiple core sets.

[0117] Figure 9 is a diagram showing the difference between the core set in the conventional control area and NR.

[0118] Referring to FIG. 9, the control area (800) in a conventional wireless communication system (e.g., LTE / LTE-A) is configured across the entire system band used by the base station. All terminals, except for some terminals that support only a narrow band (e.g., eMTC / NB-IoT terminals), had to be able to receive wireless signals across the entire system band of the base station in order to properly receive / decode control information transmitted by the base station.

[0119] On the other hand, in NR, the aforementioned core sets are introduced. The core sets (801, 802, 803) can be described as wireless resources for control information that a terminal must receive, and only a portion of the system band can be used instead of the entire system band in the frequency domain. Additionally, only some of the symbols within a slot can be used in the time domain. A base station can assign a core set to each terminal and transmit control information through the assigned core set. For example, in FIG. 9, the first core set (801) can be assigned to terminal 1, the second core set (802) can be assigned to terminal 2, and the third core set (803) can be assigned to terminal 3. In NR, a terminal can receive control information from a base station even without necessarily receiving the entire system band.

[0120] A core set may include a terminal-specific core set for transmitting terminal-specific control information and a common core set for transmitting control information common to all terminals.

[0121] Meanwhile, in NR, high reliability may be required depending on the application field, and in such situations, the target block error rate (BLER) for downlink control information (DCI) transmitted through a downlink control channel (e.g., physical downlink control channel: PDCCH) can be significantly lower than that of conventional technology. As an example of a method to satisfy such requirements for high reliability, the amount of content included in the DCI can be reduced, and / or the amount of resources used during DCI transmission can be increased. In this case, the resources may include at least one of resources in the time domain, resources in the frequency domain, resources in the code domain, and resources in the space domain.

[0122] The following technologies / features can be applied in NR.

[0123] Self-contained subframe structure

[0124] Figure 10 illustrates an example of a frame structure for a new wireless access technology.

[0125] In NR, for the purpose of minimizing latency, a structure in which the control channel and the data channel are time-division multiplexed (TDM) within a single TTI, as shown in Fig. 10, can be considered as one of the frame structures.

[0126] Figure 10 illustrates an example in which a downlink control area is located at the front of the TTI and an uplink control area is located at the back of the TTI. The area between the downlink control area and the uplink control area may be used for transmitting downlink data (DL data) or for transmitting uplink data (UL data). A characteristic of this structure is that downlink (DL) reception and uplink (UL) transmission proceed sequentially within a single subframe / slot, allowing DL data to be received and UL ACK / NACK (Acknowledgement / Not-acknowledgement) to be transmitted within a single subframe / slot. Consequently, the time required for data retransmission in the event of a data transmission error is reduced, thereby minimizing the latency of the final data delivery.

[0127] In such a data and control TDMed subframe structure, a time gap is required for the transition process between the base station and the terminal from transmit mode to receive mode or from receive mode to transmit mode. To this end, in a self-contained subframe structure, some OFDM symbols at the time of transition from DL to UL can be set as a guard period (GP).

[0128] Figure 11 illustrates the structure of a self-contained slot.

[0129] In an NR system, a single slot may contain a DL control channel, DL or UL data, a UL control channel, etc. For example, the first N symbols within the slot may be used to transmit a DL control channel (hereinafter referred to as the DL control area), and the last M symbols within the slot may be used to transmit a UL control channel (hereinafter referred to as the UL control area). N and M are each integers greater than or equal to 0. The resource area (hereinafter referred to as the data area) located between the DL control area and the UL control area may be used for transmitting DL data or for transmitting UL data. As an example, the following configuration may be considered. Each section is listed in chronological order.

[0130] 1. DL only configuration

[0131] 2. UL only configuration

[0132] 3. Mixed UL-DL Configuration

[0133] - DL Area + GP (Guard Period) + UL Control Area

[0134] - DL Control Area + GP + UL Area

[0135] DL Area: (i) DL Data Area, (ii) DL Control Area + DL Data Area

[0136] UL Area: (i) UL Data Area, (ii) UL Data Area + UL Control Area

[0137] In the DL control area, PDCCH can be transmitted, and in the DL data area, PDSCH (physical downlink shared channel) can be transmitted. In the UL control area, PUCCH (physical uplink control channel) can be transmitted, and in the UL data area, PUSCH (physical uplink shared channel) can be transmitted. In PDCCH, DCI (Downlink Control Information), such as DL data scheduling information and UL data scheduling information, can be transmitted. In PUCCH, UCI (Uplink Control Information), such as ACK / NACK (Positive Acknowledgement / Negative Acknowledgement) information for DL ​​data, CSI (Channel State Information) information, and SR (Scheduling Request), can be transmitted. GP provides a time gap during the process of the base station and the terminal switching from transmit mode to receive mode or from receive mode to transmit mode. Within a subframe, some symbols at the point of transition from DL to UL can be set as GP.

[0138] Analog Beamforming #1

[0139] In millimeter wave (mmW), the shorter wavelength allows for the installation of multiple antenna elements within the same area. Specifically, in the 30 GHz band, the wavelength is 1 cm, making it possible to install a total of 100 antenna elements in a 2-dimensional array form with a spacing of 0.5 wavelengths (lambda) on a 5 by 5 cm panel. Therefore, in mmW, multiple antenna elements are used to increase beamforming (BF) gain, thereby increasing coverage or throughput.

[0140] In this case, if a transceiver unit (TXRU) is equipped to allow for transmission power and phase control for each antenna element, independent beamforming for each frequency resource becomes possible. However, installing TXRUs for all 100 or so antenna elements presents a problem of low cost-effectiveness. Therefore, a method is being considered in which multiple antenna elements are mapped to a single TXRU and the beam direction is adjusted using an analog phase shifter. This analog beamforming method has the disadvantage of being unable to perform frequency-selective beamforming because it can only create a single beam direction across the entire band.

[0141] A hybrid beamforming (hybrid BF) can be considered as an intermediate form between digital beamforming (Digital BF) and analog beamforming (analog BF), having B TXRUs, which is fewer than Q antenna elements. In this case, although there are differences depending on the connection method between B TXRUs and Q antenna elements, the number of beam directions that can be transmitted simultaneously is limited to B or fewer.

[0142] Analog Beamforming #2

[0143] In NR systems, when multiple antennas are used, hybrid beamforming techniques combining digital and analog beamforming are emerging. In this case, analog beamforming (or RF beamforming) performs precoding (or combining) at the RF stage, which has the advantage of achieving performance close to that of digital beamforming while reducing the number of RF chains and D / A (or A / D) converters. For convenience, the above hybrid beamforming structure can be represented by N TXRUs and M physical antennas. Then, digital beamforming for L data layers to be transmitted at the transmitter can be represented by an N by L matrix, and subsequently, the converted N digital signals pass through the TXRUs to be converted into analog signals, after which analog beamforming represented by an M by N matrix is ​​applied.

[0144] System information of the NR system can be transmitted via broadcasting. In this case, analog beams belonging to different antenna panels within a single symbol can be transmitted simultaneously, and a method is being discussed to introduce a Beam Reference Signal (BRS), which is a reference signal (RS) transmitted by applying a single analog beam (corresponding to a specific antenna panel) to measure the channel for each analog beam. The BRS can be defined for multiple antenna ports, and each antenna port of the BRS can correspond to a single analog beam. In this case, unlike the BRS, the synchronization signal or xPBCH can be transmitted by applying all analog beams within an analog beam group so that any terminal can receive it well.

[0145] In NR, the synchronization signal block (SSB, or may also be referred to as the synchronization signal and physical broadcast channel: SS / PBCH) in the time domain may consist of four OFDM symbols numbered in ascending order from 0 to 3 within the synchronization signal block, and the PBCH associated with the primary synchronization signal (PSS), secondary synchronization signal (SSS), and demodulation reference signal (DMRS) may be mapped to the symbols. As previously mentioned, the synchronization signal block may also be referred to as the SS / PBCH block.

[0146] In NR, multiple synchronization signal blocks can be transmitted at different times, and since an SSB can be used to perform initial access (IA), serving cell measurement, etc., it is desirable for the SSB to be transmitted first when transmission times and resources overlap with other signals. To this end, the network can broadcast the transmission time and resource information of the SSB or indicate it through UE-specific RRC signaling.

[0147] In NR, beam-based transmission and reception operations can be performed. If the reception performance of the current serving beam deteriorates, a process to find a new beam can be performed through a process called beam failure recovery (BFR).

[0148] Since BFR is not a process that declares an error or failure regarding the link between the network and the terminal, it can be assumed that the connection with the current serving cell is maintained even when the BFR process is performed. During the BFR process, measurements are taken on different beams configured by the network (beams can be expressed as CSI-RS ports or SSB (synchronization signal block) indices, etc.), and the best beam for the terminal can be selected. The terminal can proceed with the BFR process by performing the RACH process associated with the beam for which the measurement results are good.

[0149] Now, the Transmission Configuration Indicator (TCI) state is described. The TCI state can be configured per core set of the control channel, and parameters for determining the reception (Rx) beam of the terminal can be determined based on the TCI state.

[0150] For each downlink bandwidth portion (DL BWP) of a serving cell, the terminal may be configured with three or fewer core sets. Additionally, for each core set, the terminal may be provided with the following information.

[0151] 1) Coreset index p (e.g., one of 0 to 11, in which case the index of each coreset can be uniquely determined in the BWPs of a single serving cell),

[0152] 2) PDCCH DM-RS Scrambled Sequence Initialization Value,

[0153] 3) Interval of the core set in the time domain (can be given in symbol units),

[0154] 4) Resource block set,

[0155] 5) CCE-to-REG mapping parameters,

[0156] 6) Antenna port quasi-co-location (QCL) representing the quasi-co-location information of the DM-RS antenna port for PDCCH reception in each core set (from the set of antenna port quasi-co-locations provided by the upper layer parameter called 'TCI-State'),

[0157] 7) Indication of the existence or non-existence of a transmission configuration indication (TCI) field for a specific DCI format transmitted by PDCCH in the core set, etc.

[0158] QCL is explained. If the characteristics of the channel through which a symbol on one antenna port is transmitted can be inferred from the characteristics of the channel through which a symbol on another antenna port is transmitted, then the two antenna ports can be said to be in a quasi-common location (QCL). For example, if two signals (A and B) are transmitted from the same transmission antenna array with the same / similar spatial filter applied, the two signals may experience the same / similar channel conditions. From the perspective of a receiver, if it receives one of the two signals, it can detect the other signal by utilizing the channel characteristics of the received signal.

[0159] In this sense, the fact that A and B are QCL implies that A and B have undergone similar channel conditions, and therefore, the channel information estimated to detect A may also be useful for detecting B. Here, channel conditions can be defined by, for example, Doppler shift, Doppler spread, average delay, delay spread, spatial reception parameters, etc.

[0160] The 'TCI-State' parameter associates one or two downlink reference signals with the corresponding QCL type (QCL types A, B, C, and D are available; see Table 4).

[0161] [Table 4]

[0162]

[0163] Each 'TCI-State' may include parameters for establishing a quasi-common location (QCL) relationship between one or two downlink reference signals and the DM-RS port of the PDSCH (or PDCCH) or the CSI-RS port of the CSI-RS resource.

[0164] Meanwhile, in each DL BWP configured for the terminal in a single serving cell, the terminal may be provided with 10 or fewer search space sets. For each search space set, the terminal may be provided with at least one of the following information.

[0165] 1) search space set index s (0≤s<40), 2) association between core set P and search space set s, 3) PDCCH monitoring period and PDCCH monitoring offset (in slots), 4) PDCCH monitoring pattern within a slot (e.g., indicating the first symbol of the core set within the slot for PDCCH monitoring), 5) number of slots in which search space set s exists, 6) number of PDCCH candidates per CCE aggregation level, 7) information indicating whether search space set s is CSS or USS, etc.

[0166] In NR, core set #0 can be configured by the PBCH (or terminal-specific signaling for handover, PSCell configuration, or BWP configuration). The search space (SS) set #0 configured by the PBCH may have different monitoring offsets (e.g., slot offset, symbol offset) for each associated SSB. This may be necessary to minimize the search space occasions that the terminal needs to monitor. Alternatively, it may be necessary to provide a beam sweeping control / data area capable of transmitting control / data according to each beam, so that communication with the terminal can be maintained even when the terminal's best beam changes dynamically.

[0167] FIG. 12 illustrates physical channels and general signal transmission.

[0168] Referring to FIG. 12, in a wireless communication system, a terminal receives information from a base station via a downlink (DL) and transmits information to the base station via an uplink (UL). The information transmitted and received by the base station and the terminal includes data and various control information, and various physical channels exist depending on the type / purpose of the information they transmit and receive.

[0169] When the power is turned on again after being off, or when a terminal newly enters a cell, it performs an initial cell search operation, such as synchronizing with the base station (S11). To do this, the terminal receives PSCH (Primary Synchronization Channel) and SSCH (Secondary Synchronization Channel) from the base station to synchronize with the base station and obtain information such as cell ID (cell identity). In addition, the terminal can obtain cell broadcast information by receiving PBCH (Physical Broadcast Channel) from the base station. Furthermore, during the initial cell search phase, the terminal can check the downlink channel status by receiving DL RS (Downlink Reference Signal).

[0170] After completing the initial cell search, the terminal can obtain more specific system information by receiving the PDCCH (Physical Downlink Control Channel) and the corresponding PDSCH (Physical Downlink Control Channel) (S12).

[0171] Subsequently, the terminal may perform a Random Access Procedure to complete the connection to the base station (S13~S16). Specifically, the terminal transmits a preamble through a PRACH (Physical Random Access Channel) (S13) and receives a RAR (Random Access Response) for the preamble through a PDCCH and a corresponding PDSCH (S14). Subsequently, the terminal transmits a PUSCH (Physical Uplink Shared Channel) using scheduling information within the RAR (S15) and may perform a Conflict Resolution Procedure such as a PDCCH and a corresponding PDSCH (S16).

[0172] A terminal that has performed the procedure described above may subsequently perform PDCCH / PDSCH reception (S17) and PUSCH / PUCCH (Physical Uplink Control Channel) transmission (S18) as a general uplink / downlink signal transmission procedure. The control information transmitted by the terminal to the base station is referred to as UCI (Uplink Control Information). UCI includes HARQ ACK / NACK (Hybrid Automatic Repeat and reQuest Acknowledgement / Negative-ACK), SR (Scheduling Request), CSI (Channel State Information), etc. CSI includes CQI (Channel Quality Indicator), PMI (Precoding Matrix Indicator), RI (Rank Indication), etc. UCI is generally transmitted via PUCCH, but it may be transmitted via PUSCH if control information and data need to be transmitted simultaneously. Additionally, the terminal may transmit UCI non-periodically via PUSCH in response to requests / instructions from the network.

[0173] To enable reasonable battery consumption when BA (bandwidth adaptation) is configured, only one uplink BWP and one downlink BWP or only one downlink / uplink BWP pair for each uplink carrier can be enabled at a time within an active serving cell, and all other BWPs configured in the terminal are disabled. In the disabled BWPs, the terminal does not monitor the PDCCH and does not transmit on the PUCCH, PRACH, and UL-SCH.

[0174] Regarding the BA, the terminal's receive and transmit bandwidths do not need to be as wide as the cell's bandwidth and can be adjusted: the width can be commanded to change (e.g., contracting during periods of low activity to save power), the position in the frequency domain can be shifted (e.g., to increase scheduling flexibility), and the subcarrier spacing can be commanded to change (e.g., to allow different services). A subset of the cell's total cell bandwidth is referred to as the bandwidth part (BWP), and the BA is obtained by setting the BWP(s) to the terminal and informing the terminal of which of the set BWPs is currently active. Once the BA is set, the terminal only needs to monitor the PDCCH on one active BWP. For example, there is no need to monitor the PDCCH across the cell's entire downlink frequency. A BWP inactive timer (independent of the aforementioned DRX inactive timer) is used to switch an active BWP to a default BWP: the timer is restarted when PDCCH decoding is successful, and when the timer expires, switching to the default BWP occurs.

[0175] Figure 13 illustrates a scenario in which three different bandwidth parts are set.

[0176] FIG. 13 illustrates an example in which BWP1, BWP2, and BWP3 are configured on time-frequency resources. BWP1 may have a width of 40 MHz and a subcarrier spacing of 15 kHz, BWP2 may have a width of 10 MHz and a subcarrier spacing of 15 kHz, and BWP3 may have a width of 20 MHz and a subcarrier spacing of 60 kHz. In other words, each of the bandwidth parts may have a different width and / or a different subcarrier spacing.

[0177] Now, we will explain discontinuous reception (DRX).

[0178] Figure 14 illustrates a DRX cycle.

[0179] Referring to FIG. 14, the DRX cycle may consist of an 'On Duration' (hereinafter referred to as the DRX On Duration) and an 'Opportunity for DRX'. The DRX cycle defines a time interval in which the 'On Duration' is repeated periodically. The 'On Duration' represents a time interval during which the terminal monitors to receive PDCCHs. When the DRX is established, the terminal performs PDCCH monitoring during the 'On Duration'. If a PDCCH is successfully detected during the PDCCH monitoring, the terminal activates an inactivity timer and remains in an awake state. Conversely, if no PDCCH is successfully detected during the PDCCH monitoring, the terminal enters a sleep state after the 'On Duration' ends.

[0180] Table 5 shows the process of the terminal related to DRX (RRC_CONNECTED state). Referring to Table 5, DRX configuration information is received through upper layer (e.g., RRC) signaling, and whether DRX is ON / OFF can be controlled by DRX commands at the MAC layer. When DRX is configured, PDCCH monitoring can be performed discontinuously.

[0181] [Table 5]

[0182]

[0183] The above MAC-CellGroupConfig may include configuration information necessary to set MAC (Medium Access Control) parameters for a cell group. MAC-CellGroupConfig may also include configuration information regarding DRX. For example, MAC-CellGroupConfig may include information for defining DRX as follows.

[0184] - Value of drx-OnDurationTimer: Defines the length of the start interval of the DRX cycle.

[0185] - Value of drx-InactivityTimer: Defines the length of the time interval during which the terminal remains awake after a PDCCH opportunity is detected that indicates initial UL or DL ​​data.

[0186] - Value of drx-HARQ-RTT-TimerDL: Defines the maximum time interval from when the initial DL transmission is received until when the DL retransmission is received.

[0187] - Value of drx-HARQ-RTT-TimerUL: Defines the length of the maximum time interval from when a grant for an initial UL transmission is received until when a grant for a UL retransmission is received.

[0188] - drx-LongCycleStartOffset: Defines the time length and start time of the DRX cycle.

[0189] - drx-ShortCycle (optional): Defines the time length of a short DRX cycle.

[0190] Here, if any of drx-OnDurationTimer, drx-InactivityTimer, drx-HARQ-RTT-TimerDL, or drx-HARQ-RTT-TimerDL is running, the terminal remains awake and performs PDCCH monitoring at every PDCCH opportunity.

[0191] The terminal can determine the starting point of the DRX cycle, the duration of the DRX cycle, the starting point of the on-duration timer, and the duration of the on-duration timer through the DRX configuration. Subsequently, the terminal attempts to receive / detect scheduling information (e.g., PDCCH) within the on-duration of each DRX cycle (this may also be described as monitoring scheduling information).

[0192] When scheduling information (PDCCH) is detected within the on-period of the DRX cycle, an inactivity timer is activated, and an attempt is made to detect another scheduling information during a given inactivity timer period (the time period during which the inactivity timer operates). In this case, the on-period and the inactivity timer period, during which the terminal performs signal reception / detection operations, can be referred to as the active time. If scheduling information (DCI format) is not detected within the on-period, only the on-period may be the active time.

[0193] If the disable timer expires without receiving or detecting additional signals (control signals or data), the terminal does not perform scheduling information and corresponding DL reception / UL transmission from the time the disable timer expires until the on-period (DRX on duration) of the next DRX cycle begins.

[0194] Adjusting the duration of the DRX cycle and the duration of the on-period timer / disable timer plays an important role in determining whether the terminal sleeps. Depending on the settings of these parameters, the network can be configured to put the terminal to sleep frequently or to continuously monitor scheduling information. This can serve as a factor in determining whether the terminal saves power.

[0195] In the following, a pre-synchronization signal (hereinafter referred to as the pre-sync signal) for compensating for the time / frequency offset occurring during the sleep duration of DRX mode is described.

[0196] <Discontinuous reception (DRX) operation>

[0197] Fig. 15 illustrates the operation of DRX.

[0198] Referring to Fig. 15, the terminal does not always have data to receive. Therefore, it is inefficient for the terminal to always be in active mode, and unnecessary power consumption may occur.

[0199] DRX is a function designed to reduce such power consumption. When there is no traffic, the terminal enters sleep mode for a certain period and then wakes up; when there is traffic, it enters active mode to transmit and receive data. DRX can be used in both the 'RRC connection state' (which may also be called connected mode) and the 'RRC idle state' (which may also be called idle mode).

[0200] The terminal in idle mode wakes up periodically (e.g., every paging DRX cycle) to monitor the PDCCH, transitions to connection mode to receive data when there is paging, and returns to sleep mode when there is no paging.

[0201] For a terminal in connection mode, DRX mode starts when the DRX inactivity timer (also referred to as the inactivity timer) expires, and the terminal wakes up during a DRX cycle to monitor the PDCCH. There are short and long DRX cycles; if a short DRX is configured, the terminal starts with a short DRX cycle when initiating DRX mode and then transitions to a long DRX cycle. When the RRC inactivity timer expires, the terminal transitions to idle mode and starts a paging DRX cycle.

[0202] The device's sleep mode can also be subdivided.

[0203] For example, micro sleep can refer to a state where components such as power amplifiers or low noise amplifiers (LNAs) in a terminal are turned off.

[0204] Light sleep can refer to a state in which the IC (integrated circuit) components of the transmitting and receiving ends are turned off in addition to the microsleep state.

[0205] Deep sleep can refer to a state where only components such as the terminal's internal clock are turned on, while all other components are turned off.

[0206] Figure 16 schematically illustrates the power consumption of the UE occurring during the sleep period.

[0207] Referring to Fig. 16, even when the terminal enters sleep mode, some power consumption occurs throughout the entire range, and power consumption also occurs during the process of switching between sleep mode and active mode.

[0208] [Table 6]

[0209]

[0210] Table 6 above shows the relative amount of power consumption (energy), transition energy (power) consumed when switching, and transition time when sleep modes are divided into deep sleep / light sleep / micro sleep modes.

[0211] Assuming the energy consumed per slot in deep sleep is 1, it is 20 in light sleep and 45 in micro sleep. Also, transition energy / transition time is highest in deep sleep, followed by light sleep, and then micro sleep.

[0212] From the perspective of terminal power consumption, deep sleep mode is more advantageous as the length of the sleep interval increases, and micro sleep mode is more advantageous as the length of the sleep interval decreases. Therefore, the terminal must select an appropriate sleep mode according to the DRX cycle.

[0213] Power saving enhancements

[0214] Figure 17 shows the energy consumption profile of a terminal operating in various states under various traffic conditions over 24 hours.

[0215] Referring to Figure 17, it can be seen that the energy consumed during control channel monitoring is the highest, and the time consumed is the second highest. Therefore, if the number of control channel monitoring cycles can be reduced, the total energy consumption of the terminal can be reduced.

[0216] In Connected DRX mode, the terminal must monitor the PDCCH during every on duration (active mode), regardless of whether there is received data.

[0217] The standard specification has introduced a new DCI format 2_6 (power saving signal / wake up signal: WUS) to indicate the wake-up and SCell sleep states of the connected DRX terminal.

[0218] Figure 18 shows an example of reducing the number of PDCCH monitoring cycles by indicating whether to wake up during the upcoming on-duration through the DCI prior to the DRX on-duration.

[0219] Referring to Fig. 18, the terminal can be configured with a search space for monitoring a WUS (e.g., DCI format 2_6).

[0220] If the WUS detected prior to the DRX cycle instructs the terminal to wake up (indicated by "1"), the terminal wakes up during the next ON period (which may be expressed as starting a specific timer) and performs PDCCH monitoring; if the WUS detected prior to the DRX cycle instructs the terminal to wake up or instructs that the terminal does not wake up (indicated by "0"), the terminal does not wake up during the next ON period and therefore does not perform PDCCH monitoring.

[0221] In existing paging mechanisms, regardless of whether the terminal is actually called, the terminal must monitor for paging occasions during every paging cycle, and must wake up in advance to perform time / frequency synchronization and AGC before monitoring for paging occasions.

[0222] For example, LTE performs this based on CRS, whereas NR must perform it based on SSB. Therefore, depending on the SSB transmission cycle or the received SINR, the terminal wakes up up to tens of milliseconds earlier than the paging opportunity, measures the SSB, and performs a preliminary operation.

[0223] FIG. 19 illustrates an operation related to a paging early indication (PEI) DCI.

[0224] Referring to Fig. 19, a DCI that indicates paging in advance at an earlier time than the paging opportunity, for example, a paging early indication (hereinafter PEI) DCI (e.g., DCI format 2_7), can be detected.

[0225] When a PEI DCI is received / detected and a valid paging instruction is confirmed in an EPE DCI, the terminal determines that it will be called soon and monitors for the next paging occasion (PO). Prior to the next paging occasion, the terminal is in a light sleep state / mode and can receive the SSB at the time of receiving the SSB.

[0226] On the other hand, if PEI DCI is not received / detected or a valid paging instruction is not confirmed, the terminal determines that it will not be called in the next PO and can immediately enter a deep sleep state / mode and operate at minimum power.

[0227] <CAZAC (constant amplitude zero autocorrelation) 시퀀스>

[0228] A CAZAC sequence may be a sequence having a constant amplitude and a cyclic autocorrelation of zero, except for cases where the delay is zero.

[0229] The CAZAC sequence can be defined, for example, as follows.

[0230] If N is even, , if N is odd, It could be.

[0231] The length of the CAZAC sequence is N, M is relatively prime to N, and the k-th symbol is u k am.

[0232] Power savings through DRX are more advantageous as the sleep period lengthens. However, as the sleep period lengthens, it becomes difficult to measure mobility, channel state information, and channel tracking that occur during that period, which leads to a larger time / frequency offset between the base station and the UE.

[0233] To address this, reception performance must be guaranteed by synchronizing the downlink control channel (e.g., PDCCH) or increasing the aggregation level of the PDCCH before monitoring. In particular, in NTNs, unlike terrestrial networks, the satellites where base stations are located move very rapidly, so the time / frequency offset occurring during the water surface interval can be much larger than in terrestrial networks.

[0234] One method to increase the aggregation level of PDCCH is to rate-match DCI to many resources to improve FEC performance, but this has the disadvantage of reducing resource efficiency and limiting the length of the water surface section that can be set.

[0235] In the case of a method where the terminal wakes up and synchronizes before the sleep phase prior to PDCCH monitoring, the power saving efficiency varies depending on when and for how long it wakes up. In conventional communication systems (e.g., LTE), it is sufficient to wake up immediately before PDCCH monitoring and synchronize based on a continuous CRS of several milliseconds; however, in NR, synchronization must be based on SSB, so it must wake up tens of milliseconds earlier. Consequently, in NR, if the received SINR of the SSB is low, synchronization must be achieved through multiple SSBs, and since the device must switch to a light sleep mode rather than a deep sleep mode during the time between SSBs, the power saving efficiency is reduced.

[0236] The wake-up instructions for the connected DRX mode and idle DRX mode added in NR (e.g., DCI formats 2_6, 2_7) are DCIs that inform the terminal to continue in a sleep state without monitoring PDCCH during the DRX-on period if there is no PDCCH coming to it.

[0237] From the perspective of power saving, the most ideal method is to wake up immediately before receiving such DCI or monitoring PDCCH, so that accurate synchronization can be achieved for a short period of time, thereby allowing the terminal to remain in deep sleep mode for as long as possible. However, in order to synchronize with NR, the terminal must wake up at a fixed SSB timing, which reduces the time available to enter deep sleep mode. Therefore, the present disclosure presents a method to increase the efficiency of power saving by using a pre-synchronization (pre-sync) signal.

[0238] The pre-sync signal transmitted before PDCCH monitoring must be capable of time / frequency synchronization for a short period.

[0239] To this end, the pre-sync signal proposed in this disclosure has a length N as shown in Equation 1 below. CZ You can use the CAZAC sequence and its complex conjugate.

[0240] [Equation 1]

[0241]

[0242] Figure 20 illustrates the process of generating a pre-sync signal.

[0243] Referring to FIG. 20, sequence u k Wow u k * Each of the determined subcarriers N CZ The time-domain signals of the OFDM symbols generated by performing an N-point IFFT after mapping to the symbols are sequentially denoted as U1(n) and U2(n). The root index M is N according to the definition of the CAZAC sequence. CZ It is a number that is coprime to and. In this case, a pre-sync signal can be formed by placing U1(n) and U2(n) within a certain time interval (time duration).

[0244] When a base station transmits a pre-sync signal and a terminal receives it, if a Central Frequency Offset (CFO) exists, the cross-correlation peaks of the received signal and the aforementioned U1(n) and U2(n), respectively, shift in opposite directions according to the magnitude of the CFO. The received signal may refer to any signal received during a time interval in which the terminal expects the pre-sync signal to exist (or is configured to receive the pre-sync signal), based on configuration information regarding the pre-sync signal.

[0245] Therefore, the timing sync can be estimated through the average position of the two peaks as shown in Equation 2 below.

[0246] [Equation 2]

[0247]

[0248] In addition, CFO can be estimated through the positions of the two peaks as shown in Equation 3 below.

[0249] [Equation 3]

[0250]

[0251] In the above Equations 2 and 3, Distance U1&U2 represents the transmission timing difference between U1(n) and U2(n). Position Peak_U1 , Position Peak_U2 represents the position of the cross-correlation peak between the received signal and U1(n) and U2(n), respectively, D is the down sampling rate, and SCS is the sub-carrier spacing.

[0252] This method can be viewed as similar to PSS, a synchronization method that synchronizes by cross-correlating a predefined signal with the received signal. Since PSS is transmitted by the base station at regular intervals, the terminal must receive a signal longer than the minimum PSS period to cross-correlate with the PSS; therefore, correlating directly with the received samples would increase the computational load. Consequently, while PSS detection reduces computational load by downsampling the received signal before cross-correlation, it has the disadvantage of lowering the synchronization resolution.

[0253] On the other hand, according to the present disclosure, the pre-sync signal can be transmitted, for example, through a maximum of 1 or 2 symbols, and the length of the signal that the terminal must necessarily receive can be reduced to the symbol level. Considering that the time offset that may occur during the sleep interval of the DRX cycle (which can be viewed as a difference from the point in time that serves as the reference for alignment) is likely to be at the symbol level, and that the terminal receives configuration information regarding the transmission timing of the pre-sync signal from the base station and can determine the reception time of the pre-sync signal based on this configuration information, the pre-sync signal can be transmitted in the symbol-level time domain, and the terminal can receive the signal in the symbol-level time domain. According to the method of the present disclosure, the amount of computation does not become a significant issue even if cross-correlation is performed without downsampling. If cross-correlation is performed without downsampling, the resolution of the CFO and timing offset estimated through Equation 2 is improved.

[0254] Figure 21 shows the state change over time of the proposed technique and the change in power consumption accordingly when the wake-up instruction is not set in DRX mode.

[0255] Referring to FIG. 21 (a), a pre-sync signal can be set with a minimum time gap before the PDCCH monitoring opportunity. A terminal in a deep sleep state can wake up when the pre-sync signal transmission timing arrives, synchronize with the pre-sync signal, and then proceed with PDCCH monitoring. During the minimum time gap, the terminal may be in a light sleep state.

[0256] If the SINR of the pre-sync signal is low, consecutive pre-sync signals can be set as shown in FIG. 21 (b). In this case, the terminal can perform synchronization and AGC using consecutive pre-sync signals.

[0257] Figure 22 shows the state change over time of the proposed technique and the change in power consumption accordingly when a wake-up instruction is set in DRX mode.

[0258] Referring to FIG. 22 (a), a pre-sync signal (222) can be set with a minimum time gap before the timing of the wake-up instruction (224) transmission. In this case, a terminal that was initially in a deep sleep state (221) can wake up when the timing of the pre-sync signal transmission arrives and synchronize with the pre-sync signal. Once this operation is complete, the terminal remains in a light sleep state and wakes up at the opportunity to monitor the wake-up instruction (224) to determine whether to monitor PDDCH, checks this, and if the wake-up instruction (224) is 'on', proceeds with PDCCH monitoring.

[0259] Referring to FIG. 22 (b), a pre-sync signal (226) can be set with a minimum time gap before the timing of the wake-up instruction (228) transmission. A terminal that was initially in a deep sleep state (225) can wake up when the timing of the pre-sync signal (226) transmission arrives and synchronize with the pre-sync signal. Once this operation is complete, the terminal remains in a light sleep state and wakes up at the opportunity to monitor the wake-up instruction (228) to determine whether to monitor PDDCH, checks this, and if the wake-up instruction (228) is 'off', does not proceed with PDCCH monitoring and switches to a deep sleep mode.

[0260] In FIGS. 21 and 22, the minimum time gap can be defined as the processing time for the terminal to synchronize through the pre-sync signal (or the processing time required to synchronize through the pre-sync signal).

[0261] The two sequences used by the pre-sync signal can allocate resources independently, but since synchronization is possible only if the two sequences use the same channel, the transmission interval T of the pre-sync signal c It can be limited to less than the channel coherence time.

[0262] FIG. 23 illustrates a method of operation of a terminal.

[0263] Referring to FIG. 23, the terminal receives a message setting an occasion to monitor the downlink control channel (S2310).

[0264] For example, the terminal may receive an information element (IE) that defines how and where to perform a search for PDCCH candidates via an RRC message, which is a higher-layer signal. The information element may indicate a monitoring slot through a period and an offset, indicate the number of consecutive slots within the monitoring slot, and indicate the DCI format to be searched.

[0265] For example, the information element may indicate at least one of a first DCI format for scheduling PDSCH as a DCI format to be searched, a second DCI format for scheduling PUSCH, a third DCI format including a wake-up indication, and a fourth DCI format for other purposes. The information element includes information about a CORESET to search for the corresponding DCI format and information about the search space.

[0266] The terminal can know the monitoring opportunity of the downlink control channel based on at least one of the information of the above information elements, for example, the number of the aforementioned monitoring slots, consecutive slots, CORESET, and information about the search space.

[0267] The terminal receives a pre-sync signal prior to the monitoring opportunity, wherein the pre-sync signal is a signal in which a first time domain signal generated based on a CAZAC (constant amplitude zero autocorrelation) sequence and a second time domain signal generated based on the complex conjugate of the CAZAC sequence are placed within a certain time interval (S2320). Although not illustrated in FIG. 23, the terminal may receive configuration information related to the pre-sync signal from the base station prior to receiving the pre-sync signal. The configuration information related to the pre-sync signal may, for example, inform the terminal of the transmission timing of the pre-sync signal. The configuration information related to the pre-sync signal may be set through a higher-layer signal such as an RRC message, or, depending on the embodiment, through a physical layer signal.

[0268] As described in FIG. 20, the CAZAC sequence u k Let be the complex conjugate of the above CAZAC sequence, u. k * When saying that, the above u k and u k * It can be determined based on the following Equation 4.

[0269] [Equation 4]

[0270]

[0271] In the above Equation 4, the N cz is the length of the above CAZAC sequence, and M is the root index, and N cz and are mutually prime.

[0272] The above pre-synchronous signal may be received in the above fixed time interval. Alternatively, according to an embodiment, as shown in FIG. 21 (b), the pre-synchronous signal may be received N times repeatedly in a time interval where the above fixed time interval is N consecutive (N is a natural number greater than or equal to 2, e.g., 3). The CAZAC sequence used for the pre-synchronous signal, the complex conjugate of the CAZAC sequence, and the time domain signal obtained by converting them have been described above with reference to FIG. 20.

[0273] The terminal performs synchronization based on the above-mentioned electric-synchronous signal (S2330).

[0274] For example, let the first time domain signal be U1(n) and the second time domain signal be U2(n). Then, U1(n) is the CAZAC sequence N cz It is a time-domain signal generated by performing an N-point IFFT after mapping to subcarriers, and U2(n) is a sequence obtained by complex conjugation of the above CAZAC sequence N cz It is a time-domain signal generated by performing an N-point IFFT after mapping to subcarriers. As previously mentioned, the above U1(n) and U2(n) are mapped to a certain time interval (T c It generates a full-synchronous signal by placing it within ).

[0275] The terminal cross-corresponds the received pre-sync signal with U1(n) and U2(n) to obtain two peak positions, and based on these two peak positions, it can estimate timing synchronization and also estimate CFO. This has been explained in Equations 2 and 3 above.

[0276] After performing the above synchronization, the terminal monitors the downlink control channel at the monitoring opportunity (S2340). The specific operation is described in order in FIG. 21 and FIG. 22 for the case where there is no wake-up instruction and the case where there is a wake-up instruction.

[0277] Although not illustrated in FIG. 23, the terminal may further include a step of receiving information for a wake-up indication. In this case, the pre-synchronization signal may be received or configured to be received at least a minimum time gap prior to the time at which the information for the wake-up indication is received.

[0278] The minimum time gap can be defined as the processing time for the terminal to synchronize through a pre-sync signal (or the processing time required to synchronize through a pre-sync signal).

[0279] The two sequences used for the fully synchronous signal (i.e., the CAZAC sequence and the complex conjugation of the CAZAC sequence) can be independently allocated resources, but since synchronization is possible only if the two sequences use the same channel, the transmission interval T of the fully synchronous signal c It can be limited to less than the channel coherence time.

[0280] The terminal monitors the downlink control channel at the monitoring opportunity when the above information indicates awakening, and does not monitor the downlink control channel at the monitoring opportunity when the above information does not indicate awakening.

[0281] The terminal may be in a deep sleep state before receiving the above-mentioned full-sync signal, and may be in a light sleep state from after receiving the above-mentioned full-sync signal until the monitoring opportunity.

[0282] The deep sleep state is a state in which all components except the internal clock of the terminal are turned off, and the shallow sleep state may be a state in which the power amplifier and transceiver circuit of the terminal are turned off. The terminal consumes less power in the deep sleep state compared to the shallow sleep state.

[0283] The pre-synchronous signal according to the present disclosure can be received within a time interval of the symbol unit. Therefore, even if cross-correlation is performed without downsampling, the amount of computation is not an issue, and the CFO and timing synchronization can be aligned more precisely.

[0284] Although not illustrated in FIG. 23, prior to step S2310, the terminal may include a process of connecting to a base station through a random access process. The random access process was described in FIG. 12.

[0285] According to the method described in Fig. 23, the terminal can perform accurate synchronization using a short amount of time, so it can stay in a deep sleep state / mode for as long as possible, thereby increasing the power saving effect.

[0286] FIG. 24 illustrates the signaling process and operation between a network (base station) and a terminal.

[0287] Referring to FIG. 24, the base station transmits a message to the terminal to set up a monitoring opportunity for the downlink control channel (S241), and then transmits a full-sync signal (S242).

[0288] The terminal performs synchronization based on the above-mentioned electric-synchronous signal (S243) and performs downlink control channel monitoring at the monitoring opportunity (S244).

[0289] FIG. 25 illustrates a wireless device that can be applied to the present specification.

[0290] Referring to FIG. 25, the first wireless device (100) and the second wireless device (200) can transmit and receive wireless signals through various wireless access technologies (e.g., LTE, NR).

[0291] The first wireless device (100) includes one or more processors (102) and one or more memories (104), and may additionally include one or more transceivers (106) and / or one or more antennas (108). The processor (102) controls the memory (104) and / or transceivers (106) and may be configured to implement the descriptions, functions, procedures, proposals, methods and / or flowcharts of operation disclosed in this document. For example, the processor (102) may process information within the memory (104) to generate a first information / signal and then transmit a wireless signal containing the first information / signal through the transceiver (106). Additionally, the processor (102) may receive a wireless signal containing a second information / signal through the transceiver (106) and then store information obtained from the signal processing of the second information / signal in the memory (104). The memory (104) may be connected to the processor (102) and may store various information related to the operation of the processor (102). For example, the memory (104) may store software code containing instructions for performing some or all of the processes controlled by the processor (102) or for performing the descriptions, functions, procedures, proposals, methods, and / or operation sequence diagrams disclosed in this document. Here, the processor (102) and the memory (104) may be part of a communication modem / circuit / chip designed to implement wireless communication technology (e.g., LTE, NR). The transceiver (106) may be connected to the processor (102) and may transmit and / or receive wireless signals through one or more antennas (108). The transceiver (106) may include a transmitter and / or receiver. The transceiver (106) may be combined with an RF (Radio Frequency) unit. In this specification, a wireless device may refer to a communication modem / circuit / chip.

[0292] At least one processor (102) connects to a base station through a random access process, receives a message setting an occasion for monitoring a downlink control channel, receives a pre-sync signal prior to the monitoring occasion, and performs synchronization based on the pre-sync signal. At this time, the pre-sync signal is a signal in which a first time domain signal generated based on a CAZAC (constant amplitude zero autocorrelation) sequence and a second time domain signal generated based on the complex conjugate of the CAZAC sequence are placed within a certain time interval.

[0293] The second wireless device (200) includes one or more processors (202) and one or more memories (204), and may additionally include one or more transceivers (206) and / or one or more antennas (208). The processor (202) controls the memory (204) and / or transceivers (206) and may be configured to implement the descriptions, functions, procedures, proposals, methods and / or operation sequences disclosed in this document. For example, the processor (202) may process information within the memory (204) to generate a third information / signal and then transmit a wireless signal containing the third information / signal through the transceiver (206). Additionally, the processor (202) may receive a wireless signal containing a fourth information / signal through the transceiver (206) and then store information obtained from the signal processing of the fourth information / signal in the memory (204). Memory (204) may be connected to the processor (202) and may store various information related to the operation of the processor (202). For example, memory (204) may store software code containing instructions for performing some or all of the processes controlled by the processor (202) or for performing the descriptions, functions, procedures, proposals, methods, and / or operation sequences disclosed in this document. Here, the processor (202) and memory (204) may be part of a communication modem / circuit / chip designed to implement wireless communication technology (e.g., LTE, NR). A transceiver (206) may be connected to the processor (202) and may transmit and / or receive wireless signals through one or more antennas (208). The transceiver (206) may include a transmitter and / or receiver. The transceiver (206) may be interchangeable with an RF unit. In this specification, a wireless device may mean a communication modem / circuit / chip.

[0294] At least one processor (202) connects to a terminal through a random access process and transmits a message to the terminal to set an occasion for monitoring a downlink control channel, and transmits a pre-sync signal for synchronization to the terminal prior to the monitoring occasion, wherein the pre-sync signal is a signal in which a first time domain signal generated based on a CAZAC (constant amplitude zero autocorrelation) sequence and a second time domain signal generated based on the complex conjugate of the CAZAC sequence are placed within a certain time interval.

[0295] Hereinafter, hardware elements of the wireless device (100, 200) will be described in more detail. Although not limited thereto, one or more protocol layers may be implemented by one or more processors (102, 202). For example, one or more processors (102, 202) may implement one or more layers (e.g., functional layers such as PHY, MAC, RLC, PDCP, RRC, SDAP). One or more processors (102, 202) may generate one or more Protocol Data Units (PDUs) and / or Service Data Units (SDUs) according to the descriptions, functions, procedures, proposals, methods, and / or flowcharts of operation disclosed in this document. One or more processors (102, 202) may generate messages, control information, data, or information according to the descriptions, functions, procedures, proposals, methods, and / or flowcharts of operation disclosed in this document. One or more processors (102, 202) may generate a signal (e.g., baseband signal) containing a PDU, SDU, message, control information, data, or information according to the functions, procedures, proposals, and / or methods disclosed in this document and provide it to one or more transceivers (106, 206). One or more processors (102, 202) may receive a signal (e.g., baseband signal) from one or more transceivers (106, 206) and may obtain a PDU, SDU, message, control information, data, or information according to the descriptions, functions, procedures, proposals, methods, and / or flowcharts disclosed in this document.

[0296] One or more processors (102, 202) may be referred to as a controller, microcontroller, microprocessor, or microcomputer. One or more processors (102, 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, 202). One or more processors (102, 202) may also be implemented as at least one computer-readable medium (CRM) containing instructions based on being executed by at least one processor.

[0297] For example, each method described in FIGS. 20 to 24 may be performed by at least one computer-readable medium (CRM) comprising instructions based on execution by at least one processor. The CRM connects to a base station through a random access process, receives a message from the base station setting an occasion for monitoring a downlink control channel, receives a pre-sync signal from the base station prior to the occasion, and performs synchronization based on the pre-sync signal. At this time, the pre-sync signal is characterized as a signal in which a first time-domain signal generated based on a constant amplitude zero autocorrelation (CAZAC) sequence and a second time-domain signal generated based on the complex conjugate of the CAZAC sequence are placed within a certain time interval.

[0298] The descriptions, functions, procedures, proposals, methods, and / or operation sequences disclosed in this document may be implemented using firmware or software, and the firmware or software may be implemented to include modules, procedures, functions, etc. Firmware or software configured to perform the descriptions, functions, procedures, proposals, methods, and / or operation sequences disclosed in this document may be included in one or more processors (102, 202) or stored in one or more memories (104, 204) and driven by one or more processors (102, 202). The descriptions, functions, procedures, proposals, methods, and / or operation sequences disclosed in this document may be implemented using firmware or software in the form of code, instructions, and / or sets of instructions.

[0299] One or more memories (104, 204) may be connected to one or more processors (102, 202) and may store various forms of data, signals, messages, information, programs, code, instructions, and / or commands. One or more memories (104, 204) may be composed of ROM, RAM, EPROM, flash memory, hard drive, registers, cache memory, computer read storage media, and / or combinations thereof. One or more memories (104, 204) may be located inside and / or outside of one or more processors (102, 202). Additionally, one or more memories (104, 204) may be connected to one or more processors (102, 202) through various technologies such as wired or wireless connections.

[0300] One or more transceivers (106, 206) may transmit user data, control information, wireless signals / channels, etc., as mentioned in the methods and / or operation flowcharts, etc., of this document to one or more other devices. One or more transceivers (106, 206) may receive user data, control information, wireless signals / channels, etc., as mentioned in the descriptions, functions, procedures, proposals, methods and / or operation flowcharts, etc., disclosed in this document from one or more other devices. For example, one or more transceivers (106, 206) may be connected to one or more processors (102, 202) and may transmit and receive wireless signals. For example, one or more processors (102, 202) may control one or more transceivers (106, 206) to transmit user data, control information, or wireless signals to one or more other devices. Additionally, one or more processors (102, 202) may control one or more transceivers (106, 206) to receive user data, control information, or wireless signals from one or more other devices. Additionally, one or more transceivers (106, 206) may be connected to one or more antennas (108, 208), and one or more transceivers (106, 206) may be configured to transmit and receive user data, control information, wireless signals / channels, etc., as described in the descriptions, functions, procedures, proposals, methods, and / or flowcharts of operation disclosed in this document through one or more antennas (108, 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, 206) can convert the received wireless signal / channel, etc. from an RF band signal to a baseband signal in order to process the received user data, control information, wireless signal / channel, etc. using one or more processors (102, 202).One or more transceivers (106, 206) can convert user data, control information, wireless signals / channels, etc. processed using one or more processors (102, 202) from baseband signals to RF band signals. To this end, one or more transceivers (106, 206) may include (analog) oscillators and / or filters.

[0301] FIG. 26 illustrates an example of a signal processing module structure. Here, signal processing may be performed in the processor (102, 202) of FIG. 25.

[0302] Referring to FIG. 26, a transmission device (e.g., a processor, a processor and memory, or a processor and a transceiver) within a terminal or base station may include a scrambler (301), a modulator (302), a layer mapper (303), an antenna port mapper (304), a resource block mapper (305), and a signal generator (306).

[0303] The transmission device can transmit one or more codewords. Each coded bit within a codeword is scrambled by a scrambler (301) and transmitted over a physical channel. A codeword may be referred to as a data sequence and may be equivalent to a transmission block, which is a data block provided by the MAC layer.

[0304] The scrambled bits are modulated into complex-valued modulation symbols by a modulator (302). The modulator (302) can modulate the scrambled bits according to a modulation scheme to arrange them into complex-valued modulation symbols representing positions on a signal constellation. There are no restrictions on the modulation scheme, and m-PSK (m-Phase Shift Keying) or m-QAM (m-Quadrature Amplitude Modulation), etc., may be used for modulating the encoded data. The modulator may be referred to as a modulation mapper.

[0305] The complex modulation symbols above can be mapped to one or more transmission layers by a layer mapper (303). The complex modulation symbols on each layer can be mapped by an antenna port mapper (304) for transmission on an antenna port.

[0306] The resource block mapper (305) can map complex modulation symbols for each antenna port to appropriate resource elements within a virtual resource block allocated for transmission. The resource block mapper can map the virtual resource block to a physical resource block according to an appropriate mapping scheme. The resource block mapper (305) can assign complex modulation symbols for each antenna port to appropriate subcarriers and multiplex them according to the user.

[0307] The signal generator (306) can generate a complex-valued time domain OFDM symbol signal by modulating a complex modulation symbol for each antenna port, for example, an antenna-specific symbol, using a specific modulation method, for example, OFDM (Orthogonal Frequency Division Multiplexing). The signal generator can perform an Inverse Fast Fourier Transform (IFFT) on the antenna-specific symbol, and a Cyclic Prefix (CP) can be inserted into the time domain symbol after the IFFT is performed. The OFDM symbol is transmitted to a receiving device through each transmitting antenna after undergoing digital-to-analog conversion, frequency uplink conversion, etc. The signal generator may include an IFFT module, a CP inserter, a Digital-to-Analog Converter (DAC), a frequency uplink converter, etc.

[0308] FIG. 27 illustrates another example of a signal processing module structure within a transmission device. Here, signal processing can be performed in a processor of a terminal / base station, such as the processor (102, 202) of FIG. 25.

[0309] Referring to FIG. 27, a transmission device (e.g., a processor, a processor and memory, or a processor and a transceiver) within a terminal or base station may include a scrambler (401), a modulator (402), a layer mapper (403), a precoder (404), a resource block mapper (405), and a signal generator (406).

[0310] For one codeword, the transmission device can scramble the coded bits within the codeword by the scrambler (401) and then transmit them through the physical channel.

[0311] The scrambled bits are modulated into complex modulation symbols by a modulator (402). The modulator may modulate the scrambled bits according to a predetermined modulation scheme to arrange them into complex modulation symbols representing positions on a signal constellation. There are no restrictions on the modulation scheme, and pi / 2-BPSK (pi / 2-Binary Phase Shift Keying), m-PSK (m-Phase Shift Keying), or m-QAM (m-Quadrature Amplitude Modulation), etc., may be used for modulating the encoded data.

[0312] The complex modulation symbol can be mapped to one or more transmission layers by the layer mapper (403).

[0313] Complex modulation symbols on each layer can be precoded by a precoder (404) for transmission on an antenna port. Here, the precoder may perform precoding after performing transform precoding on the complex modulation symbols. Alternatively, the precoder may perform precoding without performing transform precoding. The precoder (404) may process the complex modulation symbols in a MIMO manner according to multiple transmission antennas to output antenna-specific symbols and distribute the antenna-specific symbols to the corresponding resource block mapper (405). The output z of the precoder (404) can be obtained by multiplying the output y of the layer mapper (403) by an N-X-M precoding matrix W. Here, N is the number of antenna ports and M is the number of layers.

[0314] The resource block mapper (405) maps the demodulation modulation symbol for each antenna port to the appropriate resource element within the virtual resource block allocated for transmission.

[0315] The resource block mapper (405) can assign complex modulation symbols to appropriate subcarriers and multiplex them according to the user.

[0316] The signal generator (406) can generate a complex-valued time domain Orthogonal Frequency Division Multiplexing (OFDM) symbol signal by modulating a complex modulated symbol using a specific modulation method, such as OFDM. The signal generator (406) can perform an Inverse Fast Fourier Transform (IFFT) on an antenna-specific symbol, and a Cyclic Prefix (CP) can be inserted into the time domain symbol after the IFFT is performed. The OFDM symbol is transmitted to a receiving device through each transmitting antenna after undergoing digital-to-analog conversion, frequency uplink conversion, etc. The signal generator (406) may include an IFFT module, a CP inserter, a Digital-to-Analog Converter (DAC), a frequency uplink converter, etc.

[0317] The signal processing process of the receiving device can be configured as the inverse of the signal processing process of the transmitter. Specifically, the processor of the receiving device performs decoding and demodulation for a wireless signal received from the outside through the antenna port(s) of the transmitter and receiver. The receiving device may include multiple receiving antennas, and each signal received through the receiving antennas is restored to a baseband signal, then undergoes multiplexing and MIMO demodulation to be restored to the data sequence that the transmitting device originally intended to transmit. The receiving device (1820) may include a signal restorer for restoring the received signal to a baseband signal, a multiplexer for combining and multiplexing the received processed signals, and a channel demodulator for demodulating the multiplexed signal sequence into the corresponding codeword. The signal restorer, multiplexer, and channel demodulator may be configured as a single integrated module or as separate independent modules that perform their functions. More specifically, the signal restorer may include an analog-to-digital converter (ADC) that converts an analog signal into a digital signal, a CP remover that removes CP from the digital signal, an FFT module that applies a fast Fourier transform (FFT) to the signal from which CP has been removed to output a frequency domain symbol, and a resource element demapper / equalizer that restores the frequency domain symbol to an antenna-specific symbol. The antenna-specific symbol is restored to a transport layer by a multiplexer, and the transport layer is restored to a codeword that the transmitting device intended to transmit by a channel demodulator.

[0318] FIG. 28 illustrates an example of a wireless communication device according to an embodiment of the present disclosure.

[0319] Referring to FIG. 28, a wireless communication device, for example, a terminal, may include at least one of a processor (2310), such as a digital signal processor (DSP) or a microprocessor, a transceiver (2335), a power management module (2305), an antenna (2340), a battery (2355), a display (2315), a keypad (2320), a Global Positioning System (GPS) chip (2360), a sensor (2365), a memory (2330), a Subscriber Identification Module (SIM) card (2325), a speaker (2345), and a microphone (2350). The antenna and the processor may be in the number of multiple units.

[0320] The processor (2310) can implement the functions, procedures, and methods described in this specification. The processor (2310) of FIG. 28 may be the processor (102, 202) of FIG. 25.

[0321] The memory (2330) is connected to the processor (2310) and stores information related to the operation of the processor. The memory may be located inside or outside the processor and may be connected to the processor through various technologies such as wired or wireless connections. The memory (2330) of FIG. 28 may be the memory (104, 204) of FIG. 25.

[0322] The user can input various types of information, such as phone numbers, using various techniques, such as pressing a button on the keypad (2320) or using a microphone (2350) to activate sound. The processor (2310) receives and processes the user's information and can perform appropriate functions, such as making a call to the input phone number. In some scenarios, data may be retrieved from a SIM card (2325) or memory (2330) to perform appropriate functions. In some scenarios, the processor (2310) can display various types of information and data on a display (2315) for the user's convenience.

[0323] A transceiver (2335) is connected to a processor (2310) to transmit and / or receive a wireless signal, such as a Radio Frequency (RF) signal. The processor may control the transceiver to initiate communication or to transmit a wireless signal containing various types of information or data, such as voice communication data. The transceiver includes a transmitter and a receiver for transmitting and receiving wireless signals. An antenna (2340) may facilitate the transmission and reception of wireless signals. In some embodiments, when the transceiver receives a wireless signal, it may forward and convert the signal to a baseband frequency for processing by the processor. The processed signal may be processed by various techniques, such as being converted into audible or readable information to be output through a speaker (2345). The transceiver of FIG. 28 may be the transceiver (106, 206) of FIG. 25.

[0324] Although not illustrated in FIG. 28, various components such as a camera and a USB (Universal Serial Bus) port may be additionally included in the terminal. For example, the camera may be connected to the processor (2310).

[0325] FIG. 28 is merely one example of an implementation of a terminal, and is not limited thereto. The terminal is not required to include all the elements of FIG. 28. For example, some components, such as a keypad (2320), a Global Positioning System (GPS) chip (2360), a sensor (2365), and a SIM card (2325), may not be essential and, in this case, may not be included in the terminal.

[0326] Figure 29 illustrates another example of a wireless device.

[0327] According to FIG. 29, the wireless device may include at least one processor (102, 202), at least one memory (104, 204), at least one transceiver (106, 206), and one or more antennas (108, 208).

[0328] The difference between the example of the wireless device described in FIG. 25 and the example of the wireless device in FIG. 29 is that in FIG. 25, the processor (102, 202) and the memory (104, 204) are separated, whereas in the example of FIG. 29, the memory (104, 204) is included in the processor (102, 202). For example, the processor and the memory may form a single chipset.

[0329] FIG. 30 illustrates a communication system (1) applicable to the present specification.

[0330] Referring to FIG. 30, the communication system (1) to which the present specification applies includes a wireless device, a base station, and a network. Here, the wireless device refers to a device that performs communication using wireless access technology (e.g., 5G NR (New RAT), LTE (Long Term Evolution)) and may be referred to as a communication / wireless / 5G device. Although not limited thereto, the wireless device may include a robot (100a), a vehicle (100b-1, 100b-2), an XR (eXtended Reality) device (100c), a hand-held device (100d), a home appliance (100e), an IoT (Internet of Thing) device (100f), and an AI device / server (400). For example, the vehicle may include a vehicle equipped with wireless communication capabilities, an autonomous vehicle, a vehicle capable of performing inter-vehicle communication, etc. Here, the vehicle may include an Unmanned Aerial Vehicle (UAV) (e.g., a drone). XR devices include AR (Augmented Reality) / VR (Virtual Reality) / MR (Mixed Reality) devices and can be implemented in the form of HMDs (Head-Mounted Devices), HUDs (Head-Up Displays) equipped in vehicles, televisions, smartphones, computers, wearable devices, home appliances, digital signage, vehicles, robots, etc. Portable devices may include smartphones, smartpads, wearable devices (e.g., smartwatches, smart glasses), computers (e.g., laptops, etc.). Home appliances may include TVs, refrigerators, washing machines, etc. IoT devices may include sensors, smart meters, etc. For example, base stations and networks may be implemented as wireless devices, and a specific wireless device (200a) may operate as a base station / network node to other wireless devices.

[0331] Wireless devices (100a to 100f) can be connected to a network (300) through a base station (200). Artificial Intelligence (AI) technology may be applied to the wireless devices (100a to 100f), and the wireless devices (100a to 100f) can be connected to an AI server (400) through the network (300). The network (300) can be configured using a 3G network, a 4G (e.g., LTE) network, or a 5G (e.g., NR) network. The wireless devices (100a to 100f) may communicate with each other through the base station (200) / network (300), but they may also communicate directly (e.g., sidelink communication) without going through the base station / network. For example, vehicles (100b-1, 100b-2) can communicate directly (e.g., V2V (Vehicle to Vehicle) / V2X (Vehicle to everything) communication). Also, IoT devices (e.g., sensors) can communicate directly with other IoT devices (e.g., sensors) or other wireless devices (100a to 100f).

[0332] Wireless communication / connection (150a, 150b, 150c) can be established between wireless devices (100a~100f) / base station (200) and base station (200) / base station (200). Here, wireless communication / connection can be achieved through various wireless access technologies (e.g., 5G NR), such as uplink / downlink communication (150a), sidelink communication (150b) (or D2D communication), and inter-base station communication (150c) (e.g., relay, IAB (Integrated Access Backhaul)). Through wireless communication / connection (150a, 150b, 150c), wireless devices and base stations / wireless devices, and base stations and base stations can transmit / receive wireless signals to / from each other. For example, wireless communication / connection (150a, 150b, 150c) can transmit / receive signals through various physical channels. To this end, based on various proposals of this specification, at least some of the following may be performed: various configuration information setting processes for transmitting / receiving wireless signals, various signal processing processes (e.g., channel encoding / decoding, modulation / demodulation, resource mapping / demapping, etc.), resource allocation processes, etc.

[0333] Meanwhile, NR supports multiple numerologies (or subcarrier spacing (SCS)) to support various 5G services. For example, when the SCS is 15 kHz, it supports a wide area in traditional cellular bands; when the SCS is 30 kHz / 60 kHz, it supports dense-urban, lower latency, and wider carrier bandwidth; and when the SCS is 60 kHz or higher, it supports a bandwidth greater than 24.25 GHz to overcome phase noise.

[0334] The NR frequency band can be defined by two types of frequency ranges (FR1, FR2). The numerical values ​​of the frequency ranges may change, for example, the two types of frequency ranges (FR1, FR2) may be as shown in Table 7 below. For convenience of explanation, among the frequency ranges used in the NR system, FR1 may mean the “sub 6GHz range” and FR2 may mean the “above 6GHz range” and may be referred to as millimeter wave (mmW).

[0335] [Table 7]

[0336]

[0337] As described above, the numerical values ​​of the frequency range of the NR system may change. For example, FR1 may include a band of 410 MHz to 7125 MHz as shown in Table 8 below. For example, FR1 may include a frequency band of 6 GHz (or 5850, 5900, 5925 MHz, etc.) or higher. For example, the frequency band of 6 GHz (or 5850, 5900, 5925 MHz, etc.) or higher included within FR1 may include an unlicensed band. The unlicensed band may be used for various purposes, for example, for communication for vehicles (e.g., autonomous driving).

[0338] [Table 8]

[0339]

[0340] The claims described in this specification may be combined in various ways. For example, the technical features of the method claims in this specification may be combined to be implemented as a device, and the technical features of the device claims in this specification may be combined to be implemented as a method. Furthermore, the technical features of the method claims and the technical features of the device claims in this specification may be combined to be implemented as a device, and the technical features of the method claims and the technical features of the device claims in this specification may be combined to be implemented as a method.

Claims

1. The method is, The terminal connects to the base station through a random access process, and A terminal receives a message from the base station that sets an occasion for monitoring the downlink control channel, and Prior to the above monitoring opportunity, the terminal receives a pre-sync signal from the base station, and Based on the above-mentioned electric-synchronous signal, the terminal performs synchronization, A method characterized in that the above-described pre-synchronous signal is a signal in which a first time-domain signal generated based on a CAZAC (constant amplitude zero autocorrelation) sequence and a second time-domain signal generated based on the complex conjugate of the CAZAC sequence are arranged within a certain time interval.

2. A method according to claim 1, characterized in that, after performing the synchronization, the terminal monitors the downlink control channel at the monitoring opportunity.

3. A method according to claim 1, characterized in that the electric-synchronous signal is received within the specified time interval.

4. A method according to claim 1, characterized by receiving the pre-synchronous signal N times repeatedly in a time interval in which the predetermined time interval is N (N is a natural number greater than or equal to 2).

5. The method of claim 1, further comprising the step of receiving information for a wake-up indication, wherein the pre-synchronization signal is received prior to a minimum time gap from the time of receiving the information.

6. A method according to claim 5, characterized in that the terminal monitors the downlink control channel at the monitoring opportunity based on the information indicating awakening.

7. A method according to claim 5, characterized in that the terminal does not monitor the downlink control channel in the monitoring opportunity based on the fact that the information does not indicate awakening.

8. In claim 1, the CAZAC sequence u k Let be the complex conjugate of the above CAZAC sequence, u. k * When saying, The above u k and u k * is determined based on the following equation, and [ceremony] In the above formula, the N cz is the length of the above CAZAC sequence, and M is the root index, and N cz A method characterized by being relatively prime to .

9. In claim 1, the terminal is in a deep sleep state before receiving the electric synchronization signal, and is in a light sleep state from receiving the electric synchronization signal until the monitoring opportunity, A method characterized in that the deep sleep state is a state in which all components except the internal clock of the terminal are turned off, and the shallow sleep state is a state in which the power amplifier and the transmission / reception circuit of the terminal are turned off.

10. A method according to claim 9, characterized in that the terminal consumes less power in the deep sleep state compared to the shallow sleep state.

11. A terminal (User Equipment; UE) is, At least one transceiver; At least one memory; and at least one processor operating in combination with the above-mentioned at least one transceiver and the above-mentioned at least one memory; comprising, The above at least one memory includes instructions that cause the at least one processor to perform operations based on execution by the at least one processor, wherein The above operations are The above terminal connects to the base station through a random access process, and The terminal receives a message from the base station that sets an occasion for monitoring the downlink control channel, and Prior to the above monitoring opportunity, the terminal receives a pre-sync signal from the base station, and Based on the above-mentioned electric-synchronous signal, the terminal performs synchronization, A terminal characterized in that the above-described pre-synchronous signal is a signal in which a first time-domain signal generated based on a CAZAC (constant amplitude zero autocorrelation) sequence and a second time-domain signal generated based on the complex conjugate of the CAZAC sequence are arranged within a certain time interval.

12. A terminal according to claim 11, characterized in that, after performing the synchronization, the terminal monitors the downlink control channel at the monitoring opportunity.

13. A terminal according to claim 11, characterized in that the electric-synchronous signal is received during the specified time interval.

14. A terminal according to claim 11, characterized by receiving the pre-synchronous signal N times repeatedly in a time interval in which the predetermined time interval is N (N is a natural number greater than or equal to 2).

15. A terminal according to claim 11, characterized in that it receives information for a wake-up indication, wherein the pre-synchronization signal is received prior to a minimum time gap from the time of receiving the information.

16. A terminal according to claim 15, characterized in that the terminal monitors the downlink control channel at the monitoring opportunity based on the information indicating awakening.

17. A terminal according to claim 15, characterized in that the terminal does not monitor the downlink control channel in the monitoring opportunity based on the fact that the information does not indicate a wake-up.

18. In claim 11, the CAZAC sequence u k Let be the complex conjugate of the above CAZAC sequence, u. k * When saying, The above u k and u k * is determined based on the following equation, and [ceremony] In the above formula, the N cz is the length of the above CAZAC sequence, and M is the root index, and N cz A terminal characterized by being relatively prime to .

19. In claim 11, the terminal is in a deep sleep state before receiving the full-sync signal, and is in a light sleep state from receiving the full-sync signal until the monitoring opportunity, A terminal characterized in that the deep sleep state is a state in which all components except the internal clock of the terminal are turned off, and the shallow sleep state is a state in which the power amplifier and the transmission / reception circuit of the terminal are turned off.

20. A terminal according to claim 19, characterized in that the terminal consumes less power in the deep sleep state compared to the light sleep state.

21. Regarding the method, The base station connects with the terminal through a random access process, and The base station transmits a message to the terminal that sets an occasion for monitoring the downlink control channel, and Prior to the above monitoring opportunity, the base station transmits a pre-sync signal for synchronization to the terminal, A method characterized in that the above-described pre-synchronous signal is a signal in which a first time-domain signal generated based on a CAZAC (constant amplitude zero autocorrelation) sequence and a second time-domain signal generated based on the complex conjugate of the CAZAC sequence are arranged within a certain time interval.

22. A base station is, At least one transceiver; At least one memory; and at least one processor operating in combination with the above-mentioned at least one transceiver and the above-mentioned at least one memory; comprising, The above at least one memory includes instructions that cause the at least one processor to perform operations based on execution by the at least one processor, wherein The above operations are The base station connects with the terminal through a random access process, and The base station transmits a message to the terminal that sets an occasion for monitoring the downlink control channel, and The method includes the base station transmitting a pre-sync signal for synchronization to the terminal prior to the above monitoring opportunity, wherein A base station characterized in that the above-mentioned pre-synchronous signal is a signal in which a first time domain signal generated based on a CAZAC (constant amplitude zero autocorrelation) sequence and a second time domain signal generated based on the complex conjugate of the CAZAC sequence are arranged within a certain time interval.

23. At least one computer-readable storage medium comprising instructions that are executed by at least one processor and cause said at least one processor to perform operations, The above operations are Connect to the base station through a random access process, and A message is received from the base station to set an occasion for monitoring the downlink control channel, and Received a pre-sync signal from the base station prior to the above monitoring opportunity, and Synchronization is performed based on the above-mentioned pre-synchronous signal, but includes At least one computer-readable storage medium characterized in that the above-mentioned pre-synchronous signal is a signal in which a first time-domain signal generated based on a CAZAC (constant amplitude zero autocorrelation) sequence and a second time-domain signal generated based on the complex conjugate of the CAZAC sequence are arranged within a certain time interval.

24. A device operating in a wireless communication system, At least one memory; and at least one processor that operates in combination with the above at least one memory; comprising, The above at least one memory includes instructions that cause the at least one processor to perform operations based on execution by the at least one processor, wherein The above operations are Connect to the base station through a random access process, and A message is received from the base station to set an occasion for monitoring the downlink control channel, and Prior to the above monitoring opportunity, a pre-sync signal is received from the base station, and Synchronization is performed based on the above-mentioned pre-synchronous signal, but includes The above-described pre-synchronous signal is a signal in which a first time-domain signal generated based on a CAZAC (constant amplitude zero autocorrelation) sequence and a second time-domain signal generated based on the complex conjugate of the CAZAC sequence are arranged within a certain time interval.

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