Synchronization acquisition method and device in wireless communication system

Abstract

Disclosed are a synchronization acquisition method and device in a wireless communication system. The method, according to one embodiment of the present disclosure, may comprise the steps in which: a first signal for timing acquisition is transmitted to a second device by a first device; a first channel is transmitted to the second device by the first device; and, as a response to the first channel, a second channel is received from the second device by the first device.

Description

Method and device for obtaining synchronization in a wireless communication system

[0001] The present disclosure relates to a wireless communication system, and more particularly, to a method and device for obtaining synchronization in a wireless communication system.

[0002] Mobile communication systems were developed to provide voice services while ensuring user activity. However, they have expanded beyond voice to include data services. Currently, explosive growth in traffic is leading to resource shortages and users' demand for higher-speed services, necessitating a more advanced mobile communication system.

[0003] Next-generation mobile communication systems must support explosive data traffic growth, dramatically increasing data rates per user, a vastly increased number of connected devices, ultra-low end-to-end latency, and high energy efficiency. To achieve these goals, various technologies are being studied, including dual connectivity, massive multiple input multiple output (MIMO), in-band full duplex, non-orthogonal multiple access (NOMA), super wideband support, and device networking.

[0004] The technical problem of the present disclosure is to provide a method and device for obtaining synchronization between devices in a wireless communication system supporting the ambient internet of things (A-IoT).

[0005] In addition, an additional technical task of the present disclosure is to provide a method and device for transmitting and receiving downlink / uplink synchronization signals in a wireless communication system supporting A-IoT.

[0006] The technical problems to be achieved in the present disclosure are not limited to the technical problems mentioned above, and other technical problems not mentioned can be clearly understood by a person having ordinary skill in the technical field to which the present disclosure belongs from the description below.

[0007] A method according to an aspect of the present disclosure may include: transmitting, by a first device, a first signal for timing acquisition to a second device; transmitting, by the first device, a first channel to the second device; and receiving, by the first device, a second channel from the second device in response to the first channel. The first signal may include an ON / OFF pattern so that the first signal can be distinguished from the first channel and information for determining a time unit for transmission of data in the first channel and / or the second channel.

[0008] A method according to an additional aspect of the present disclosure may include: receiving, by a second device, a first signal for timing acquisition from a first device; receiving, by the second device, a first channel from the first device; and transmitting, by the second device, a second channel to the first device in response to the first channel. The first signal may include an ON / OFF pattern such that the first signal can be distinguished from the first channel and information for determining a time unit for transmission of data in the first channel and / or the second channel.

[0009] According to an embodiment of the present disclosure, in a wireless communication system supporting A-IoT, transmission and reception of subsequent data can be performed smoothly as synchronization between devices is obtained through a synchronization signal (e.g., a preamble or frame synchronization signal).

[0010] In addition, according to an embodiment of the present disclosure, ambiguity in the operation of a device can be prevented by distinguishing between a synchronization signal and data transmission in a wireless communication system supporting A-IoT.

[0011] In addition, according to an embodiment of the present disclosure, smooth data transmission is possible by providing various information for data transmission in a synchronization signal in a wireless communication system supporting A-IoT.

[0012] The effects that can be obtained from the present disclosure are not limited to the effects mentioned above, and other effects that are not mentioned will be clearly understood by a person having ordinary skill in the art to which the present disclosure pertains from the description below.

[0013] The accompanying drawings, which are incorporated in and are part of the detailed description to aid in understanding the present disclosure, provide embodiments of the present disclosure and, together with the detailed description, describe the technical features of the present disclosure.

[0014] Figure 1 illustrates the structure of a wireless communication system to which the present disclosure can be applied.

[0015] FIG. 2 illustrates a frame structure in a wireless communication system to which the present disclosure can be applied.

[0016] FIG. 3 illustrates a resource grid in a wireless communication system to which the present disclosure can be applied.

[0017] FIG. 4 illustrates a physical resource block in a wireless communication system to which the present disclosure can be applied.

[0018] FIG. 5 illustrates a slot structure in a wireless communication system to which the present disclosure can be applied.

[0019] FIG. 6 illustrates physical channels used in a wireless communication system to which the present disclosure can be applied and a general signal transmission and reception method using the same.

[0020] FIG. 7 illustrates an ambient IoT device architecture in a wireless communication system to which the present disclosure can be applied.

[0021] FIG. 8 illustrates an overall procedure between an A-IoT device and a reader in a wireless communication system to which the present disclosure can be applied.

[0022] FIG. 9 illustrates a logical system architecture in a wireless communication system to which the present disclosure can be applied.

[0023] FIG. 10 is a diagram illustrating A-IoT operation in a wireless communication system to which the present disclosure can be applied.

[0024] FIG. 11 illustrates the operation of a device for obtaining synchronization according to one embodiment of the present disclosure.

[0025] FIG. 12 illustrates the operation of a device for obtaining synchronization according to one embodiment of the present disclosure.

[0026] FIG. 13 illustrates a block diagram of a wireless communication device according to one embodiment of the present disclosure.

[0027] Hereinafter, preferred embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. The detailed description set forth below, together with the accompanying drawings, is intended to explain exemplary embodiments of the present disclosure and is not intended to represent the only embodiments in which the present disclosure may be practiced. The following detailed description includes specific details to provide a thorough understanding of the present disclosure. However, one of ordinary skill in the art will appreciate that the present disclosure may be practiced without these specific details.

[0028] In some cases, to avoid obscuring the concepts of the present disclosure, known structures and devices may be omitted or illustrated in block diagram form focusing on the core functions of each structure and device.

[0029] In the present disclosure, when a component is said to be "connected," "coupled," or "connected" to another component, this may include not only a direct connection but also an indirect connection in which another component exists between them. Furthermore, the terms "comprises" or "has" in the present disclosure specify the presence of the mentioned features, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, elements, components, and / or groups thereof.

[0030] In this disclosure, terms such as “first,” “second,” etc. are used only to distinguish one component from another and are not used to limit the components, and do not limit the order or importance between the components unless specifically stated otherwise. Accordingly, within the scope of this disclosure, a first component in one embodiment may be referred to as a second component in another embodiment, and similarly, a second component in one embodiment may be referred to as a first component in another embodiment.

[0031] The terminology used herein is for the purpose of describing particular embodiments and is not intended to limit the scope of the claims. As used in the description of the embodiments and the appended claims, the singular forms "a," "an," and "the" are intended to include the plural forms as well, unless the context clearly dictates otherwise. The term "and / or" as used herein may refer to any one of the associated enumerated items, or is meant to refer to and encompass any and all possible combinations of two or more of them. Furthermore, the use of " / " between words in this disclosure has the same meaning as "and / or" unless otherwise stated.

[0032] The present disclosure describes a wireless communication network or a wireless communication system, and an operation performed in a wireless communication network may be performed in a process of controlling the network and transmitting or receiving a signal from a device (e.g., a base station) that manages the wireless communication network, or may be performed in a process of transmitting or receiving a signal to or between terminals connected to the wireless network.

[0033] In the present disclosure, transmitting or receiving a channel means transmitting or receiving information or a signal through the channel. For example, transmitting a control channel means transmitting control information or a signal through the control channel. Similarly, transmitting a data channel means transmitting data information or a signal through the data channel.

[0034] Hereinafter, downlink (DL) refers to communication from a base station to a terminal, and uplink (UL) refers to communication from a terminal to a base station. In downlink, a transmitter may be part of a base station, and a receiver may be part of a terminal. In uplink, a transmitter may be part of a terminal, and a receiver may be part of a base station. A base station may be expressed as a first communication device, and a terminal may be expressed as a second communication device. A base station (BS) may be replaced by terms such as a fixed station, Node B, eNB (evolved-NodeB), gNB (Next Generation NodeB), BTS (base transceiver system), access point (AP: Access Point), network (5G network), AI (Artificial Intelligence) system / module, RSU (road side unit), robot, drone (UAV: Unmanned Aerial Vehicle), AR (Augmented Reality) device, VR (Virtual Reality) device, etc.In addition, the terminal may be fixed or mobile, and may be replaced with terms such as UE (User Equipment), MS (Mobile Station), UT (user terminal), MSS (Mobile Subscriber Station), SS (Subscriber Station), AMS (Advanced Mobile Station), WT (Wireless terminal), MTC (Machine-Type Communication) device, M2M (Machine-to-Machine) device, D2D (Device-to-Device) device, vehicle, RSU (road side unit), robot, AI (Artificial Intelligence) module, UAV (Unmanned Aerial Vehicle), AR (Augmented Reality) device, VR (Virtual Reality) device, etc.

[0035] The following technologies can be used in various wireless access systems, such as CDMA, FDMA, TDMA, OFDMA, and SC-FDMA. CDMA can be implemented using wireless technologies such as UTRA (Universal Terrestrial Radio Access) or CDMA2000. TDMA can be implemented using wireless technologies such as GSM (Global System for Mobile communications) / GPRS (General Packet Radio Service) / EDGE (Enhanced Data Rates for GSM Evolution). OFDMA can be implemented using wireless technologies such as IEEE 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802-20, and E-UTRA (Evolved UTRA). UTRA is part of UMTS (Universal Mobile Telecommunications System). 3GPP (3rd Generation Partnership Project) LTE (Long Term Evolution) is a part of E-UMTS (Evolved UMTS) that uses E-UTRA, and LTE-A (Advanced) / LTE-A pro is an evolved version of 3GPP LTE. 3GPP NR (New Radio or New Radio Access Technology) is an evolved version of 3GPP LTE / LTE-A / LTE-A pro.

[0036] For clarity, the description is based on a 3GPP communication system (e.g., LTE-A, NR), but the technical idea of ​​the present disclosure is not limited thereto. LTE refers to technology after 3GPP TS (Technical Specification) 36.xxx Release 8. Specifically, LTE technology after 3GPP TS 36.xxx Release 10 is referred to as LTE-A, and LTE technology after 3GPP TS 36.xxx Release 13 is referred to as LTE-A pro. 3GPP NR refers to technology after TS 38.xxx Release 15. LTE / NR may be referred to as a 3GPP system. "xxx" refers to a standard document detail number. LTE / NR may be collectively referred to as a 3GPP system. For background technology, terms, abbreviations, etc. used in the description of the present disclosure, reference may be made to matters described in standard documents published prior to the present disclosure. For example, reference may be made to the following documents.

[0037] For 3GPP LTE, see TS 36.211 (Physical channels and modulation), TS 36.212 (Multiplexing and channel coding), TS 36.213 (Physical layer procedures), TS 36.300 (General description), and TS 36.331 (Radio resource control).

[0038] For 3GPP NR, see TS 38.211 (Physical channels and modulation), TS 38.212 (Multiplexing and channel coding), TS 38.213 (Physical layer procedures for control), TS 38.214 (Physical layer procedures for data), TS 38.300 (Overall description of NR and New Generation-Radio Access Network (NG-RAN)), and TS 38.331 (Radio Resource Control Protocol Specification).

[0039] Abbreviations for terms that may be used in this disclosure are defined as follows.

[0040] - BM: beam management

[0041] - CQI: Channel Quality Indicator

[0042] - CRI: Channel state information - reference signal resource indicator

[0043] - CSI: Channel State Information

[0044] - CSI-IM: Channel State Information - Interference Measurement

[0045] - CSI-RS: Channel state information - reference signal

[0046] - DMRS: Demodulation Reference Signal

[0047] - FDM: frequency division multiplexing

[0048] - FFT: fast Fourier transform

[0049] - IFDMA: interleaved frequency division multiple access

[0050] - IFFT: inverse fast Fourier transform

[0051] - L1-RSRP: Layer 1 reference signal received power

[0052] - L1-RSRQ: Layer 1 reference signal received quality

[0053] - MAC: Medium Access Control

[0054] - NZP: non-zero power

[0055] - OFDM: orthogonal frequency division multiplexing

[0056] - PDCCH: Physical downlink control channel

[0057] - PDSCH: Physical downlink shared channel

[0058] - PMI: precoding matrix indicator

[0059] - RE: resource element

[0060] - RI: Rank indicator

[0061] - RRC: Radio Resource Control

[0062] - RSSI: Received signal strength indicator

[0063] - Rx: Reception

[0064] - QCL: quasi co-location

[0065] - SINR: signal to interference and noise ratio

[0066] - SSB (or SS / PBCH block): Synchronization signal block (including primary synchronization signal (PSS), secondary synchronization signal (SSS), and physical broadcast channel (PBCH))

[0067] - TDM: Time Division Multiplexing

[0068] - TRP: transmission and reception point

[0069] - TRS: Tracking Reference Signal

[0070] - Tx: transmission

[0071] - UE: user equipment

[0072] - ZP: Zero Power

[0073] System General

[0074] As more and more communication devices demand greater communication capacity, the need for improved mobile broadband communications compared to existing radio access technologies (RATs) is emerging. Furthermore, massive Machine Type Communications (MTC), which connects numerous devices and objects to provide diverse services anytime, anywhere, is also a key issue to be considered in next-generation communications. Furthermore, communication system design that considers reliability and latency-sensitive services / terminals is being discussed. Accordingly, the introduction of next-generation RATs that consider enhanced mobile broadband communication (eMBB), massive MTC (MMTC), and Ultra-Reliable and Low Latency Communication (URLLC) is being discussed. For convenience, these technologies are referred to as NR in this disclosure. NR is an expression representing an example of 5G RAT.

[0075] A new RAT system, including NR, uses OFDM or a similar transmission scheme. The new RAT system may follow OFDM parameters different from those of LTE. Alternatively, the new RAT system may follow the existing LTE / LTE-A numerology but support a larger system bandwidth (e.g., 100 MHz). Alternatively, a single cell may support multiple numerologies. That is, terminals operating under different numerologies can coexist within a single cell.

[0076] A numerology corresponds to a single subcarrier spacing in the frequency domain. Different numerologies can be defined by scaling the reference subcarrier spacing by an integer N.

[0077] Figure 1 illustrates the structure of a wireless communication system to which the present disclosure can be applied.

[0078] Referring to Fig. 1, the NG-RAN consists of gNBs that provide NG-RA (NG-Radio Access) user plane (i.e., new AS (access stratum) sublayer / PDCP (Packet Data Convergence Protocol) / RLC (Radio Link Control) / MAC / PHY) and control plane (RRC) protocol termination for UE. The gNBs are interconnected via Xn interfaces. The gNBs are also connected to the NGC (New Generation Core) via the NG interface. More specifically, the gNBs are connected to the AMF (Access and Mobility Management Function) via the N2 interface and to the UPF (User Plane Function) via the N3 interface.

[0079] FIG. 2 illustrates a frame structure in a wireless communication system to which the present disclosure can be applied.

[0080] NR systems can support multiple numerologies. Numerologies can be defined by subcarrier spacing and cyclic prefix (CP) overhead. Multiple subcarrier spacings can be derived by scaling the base (reference) subcarrier spacing by an integer N (or μ). Furthermore, even if it is assumed that very low subcarrier spacing is not used at very high carrier frequencies, the numerology used can be selected independently of the frequency band. Furthermore, NR systems can support various frame structures corresponding to multiple numerologies.

[0081] Below, we examine OFDM numerologies and frame structures that can be considered in NR systems. The various OFDM numerologies supported in NR systems can be defined as shown in Table 1 below.

[0082] μΔf=2 μ ·15 [kHz]CP015 Normal 130 Normal 260 Normal, Extended 3120 Normal 4240 Normal

[0083] NR supports multiple numerologies (or subcarrier spacings (SCS)) to support various 5G services. For example, an SCS of 15 kHz supports wide areas in traditional cellular bands; an SCS of 30 kHz / 60 kHz supports dense urban areas, lower latency, and wider carrier bandwidth; and an SCS of 60 kHz or higher supports bandwidths greater than 24.25 GHz to overcome phase noise.

[0084] The NR frequency band is defined by two types of frequency ranges (FR1 and FR2). FR1 and FR2 can be configured as shown in Table 2 below. FR2 can also mean millimeter wave (mmW).

[0085] Frequency Range Designation Corresponding Frequency Range Subcarrier Spacing FR1410MHz - 7125MHz 15, 30, 60kHz FR224250MHz - 52600MHz 60, 120, 240kHz

[0086] Regarding the frame structure in the NR system, the sizes of the various fields in the time domain are T c =1 / (Δf max ·N f ) is expressed as a multiple of the time unit. Here, Δf max =480·10 3 Hz and N f =4096. Downlink and uplink transmissions are T f =1 / (Δf max N f / 100)·T c = It is organized into radio frames with a duration of 10ms. Here, each radio frame is T sf =(Δf max N f / 1000)·T c =1ms It consists of 10 subframes with an interval of . In this case, there may be one set of frames for uplink and one set of frames for downlink. In addition, transmission in uplink frame number i from a terminal is T earlier than the start of the corresponding downlink frame from the terminal.TA =(N TA +N TA,offset )T c It should start before. For the subcarrier spacing configuration μ, slots are n within a subframe. s μ ∈{0,..., N slot subframe,μ-1} are numbered in increasing order, and n within a radio frame. s,f μ ∈{0,..., N slot frame,μ -1} are numbered in increasing order. One slot is N symb slot It consists of consecutive OFDM symbols, and N symb slot is determined by CP. Slot n in subframe s μ The start of OFDM symbol n in the same subframe s μ N symb slot are aligned temporally with the start of the OFDM signal. Not all terminals can transmit and receive simultaneously, which means that not all OFDM symbols in a downlink slot or uplink slot can be utilized.

[0087] Table 3 shows the number of OFDM symbols per slot in a general CP (N symb slot ), the number of slots per wireless frame (N slot frame,μ ), number of slots per subframe (N slot subframe,μ), and Table 4 shows the number of OFDM symbols per slot in the extended CP, the number of slots per radio frame, and the number of slots per subframe.

[0088] μN symb slot N slot frame,μ N slotsubframe,μ01410111420221440431480841416016

[0089] μN symb slot N slot frame,μ N slot subframe,μ212404

[0090] FIG. 2 is an example when μ=2 (SCS is 60 kHz), and referring to Table 3, 1 subframe can include 4 slots. 1 subframe={1,2,4} slot illustrated in FIG. 2 is an example, and the number of slot(s) that can be included in 1 subframe is defined as in Table 3 or Table 4. In addition, a mini-slot can include 2, 4, or 7 symbols, or more or fewer symbols.

[0091] Regarding physical resources in an NR system, antenna ports, resource grids, resource elements, resource blocks, carrier parts, etc. can be considered. Below, the physical resources that can be considered in an NR system will be examined in detail.

[0092] First, with respect to antenna ports, antenna ports are defined such that the channel through which a symbol on an antenna port is carried can be inferred from the channel through which another symbol on the same antenna port is carried. Two antenna ports are said to be in a QC / QCL (quasi co-located or quasi co-location) relationship if the large-scale properties of the channel through which a symbol on one antenna port is carried can be inferred from the channel through which a symbol on another antenna port is carried. Here, the large-scale properties include one or more of delay spread, Doppler spread, frequency shift, average received power, and received timing.

[0093] FIG. 3 illustrates a resource grid in a wireless communication system to which the present disclosure can be applied.

[0094] Referring to Figure 3, the resource grid is N in the frequency domain. RB μ N sc RB It consists of subcarriers, and one subframe is 14·2 μ It is described as an example, but not limited to, that it consists of OFDM symbols. In an NR system, the transmitted signal is N RB μ N sc RB One or more resource grids consisting of subcarriers and 2 μ N symb (μ) is described by OFDM symbols. Here, N RB μ≤ N RB max,μ is. The above N RB max,μrepresents the maximum transmission bandwidth, which may vary between uplink and downlink as well as between numerologies. In this case, one resource grid may be configured for μ and antenna port p. Each element of the resource grid for μ and antenna port p is referred to as a resource element and is uniquely identified by an index pair (k, l'), where k=0,...,N. RB μ N sc RB -1 is the index in the frequency domain, and l'=0,...,2 μ N symb (μ) -1 indicates the position of the symbol within the subframe. When referring to a resource element in a slot, an index pair (k,l) is used. Here, l=0,...,N symb μ -1. The resource element (k,l') for μ and antenna port p is a complex value a k,l' (p,μ) . If there is no risk of confusion or if a particular antenna port or numerology is not specified, the indices p and μ can be dropped, resulting in a complex value of a k,l' (p) or a k,l' This can be. Also, a resource block (RB) is N in the frequency domain. sc RB =12 is defined as consecutive subcarriers.

[0095] Point A serves as a common reference point of the resource block grid and is obtained as follows.

[0096] - offsetToPointA for the Primary Cell (PCell) downlink represents the frequency offset between point A and the lowest subcarrier of the lowest resource block overlapping the SS / PBCH block used by the UE for initial cell selection. It is expressed in resource block units assuming 15 kHz subcarrier spacing for FR1 and 60 kHz subcarrier spacing for FR2.

[0097] - absoluteFrequencyPointA represents the frequency-position of point A expressed as ARFCN (absolute radio-frequency channel number).

[0098] Common resource blocks (CRBs) are numbered from 0 upwards in the frequency domain for a subcarrier spacing setting μ. The center of subcarrier 0 of CRB 0 for a subcarrier spacing setting μ coincides with 'point A'. CRB number n in the frequency domain CRB μ The relationship between the resource elements (k,l) and the subcarrier spacing setting μ is given by the following mathematical expression 1.

[0099]

[0100] In Equation 1, k is defined relative to point A such that k = 0 corresponds to the subcarrier centered at point A. Physical resource blocks are numbered from 0 to N within the bandwidth part (BWP). BWP,i size,μ - Numbered from -1, where i is the number of the BWP. Physical resource block n in BWP i PRB and common resource block n CRB The relationship between them is given by the mathematical formula 2 below.

[0101]

[0102] N BWP,i start,μ is a common resource block where BWP starts relative to common resource block 0.

[0103] FIG. 4 illustrates a physical resource block in a wireless communication system to which the present disclosure can be applied. FIG. 5 illustrates a slot structure in a wireless communication system to which the present disclosure can be applied.

[0104] Referring to FIGS. 4 and 5, a slot includes multiple symbols in the time domain. For example, in the case of a normal CP, one slot includes seven symbols, but in the case of an extended CP, one slot includes six symbols.

[0105] A carrier comprises multiple subcarriers in the frequency domain. An RB (Resource Block) is defined as multiple (e.g., 12) consecutive subcarriers in the frequency domain. A BWP (Bandwidth Part) is defined as multiple consecutive (physical) resource blocks in the frequency domain, and can correspond to a single numerology (e.g., SCS, CP length, etc.). A carrier can comprise up to N (e.g., 5) BWPs. Data communication is performed through activated BWPs, and only one BWP can be activated for a single terminal. Each element in the resource grid is referred to as a Resource Element (RE), to which one complex symbol can be mapped.

[0106] The NR system can support up to 400 MHz per component carrier (CC). If a terminal operating in such a wideband CC always operates with the radio frequency (RF) chip for the entire CC turned on, the terminal battery consumption may increase. Alternatively, when considering multiple use cases operating within a single wideband CC (e.g., eMBB, URLLC, Mmtc, V2X, etc.), different numerologies (e.g., subcarrier spacing, etc.) may be supported for each frequency band within the CC. Alternatively, each terminal may have different maximum bandwidth capabilities. Considering this, the base station can instruct the terminal to operate only on a portion of the bandwidth rather than the entire bandwidth of the wideband CC, and this portion of bandwidth is conveniently defined as the bandwidth part (BWP). A BWP can be composed of consecutive RBs on the frequency axis and can correspond to a single numerology (e.g., subcarrier spacing, CP length, slot / mini-slot interval).

[0107] Meanwhile, the base station can configure multiple BWPs even within a single CC configured for a terminal. For example, in the PDCCH monitoring slot, a BWP occupying a relatively small frequency range can be configured, and the PDSCH indicated by the PDCCH can be scheduled on a larger BWP. Alternatively, if UEs are concentrated on a specific BWP, some terminals can be configured to a different BWP for load balancing. Alternatively, considering frequency domain inter-cell interference cancellation between neighboring cells, a portion of the spectrum in the middle of the entire bandwidth can be excluded and both BWPs can be configured within the same slot. In other words, the base station can configure at least one DL / UL BWP for a terminal associated with a wideband CC. The base station can activate at least one DL / UL BWP(s) among the configured DL / UL BWP(s) at a specific time (via L1 signaling, MAC CE (Control Element), RRC signaling, etc.). Additionally, the base station can instruct switching to another configured DL / UL BWP (e.g., via L1 signaling or MAC CE or RRC signaling). Alternatively, switching to a configured DL / UL BWP can be performed based on a timer when the timer value expires. In this case, the activated DL / UL BWP is defined as the active DL / UL BWP. However, in situations such as when the terminal is performing the initial access process or before the RRC connection is set up, the configuration for the DL / UL BWP may not be received. Therefore, in these situations, the DL / UL BWP assumed by the terminal is defined as the initially active DL / UL BWP.

[0108] FIG. 6 illustrates physical channels used in a wireless communication system to which the present disclosure can be applied and a general signal transmission and reception method using the same.

[0109] In wireless communication systems, terminals receive information from a base station via the downlink and transmit it to the base station via the uplink. The information transmitted and received between the base station and terminals includes data and various control information, and various physical channels exist depending on the type and purpose of the information being transmitted and received.

[0110] When a terminal is powered on or enters a new cell, it performs an initial cell search operation, such as synchronizing with the base station (S601). To this end, the terminal receives a primary synchronization signal (PSS) and a secondary synchronization signal (SSS) from the base station to synchronize with the base station and obtain information such as a cell identifier (ID). Afterwards, the terminal can receive a physical broadcast channel (PBCH) from the base station to obtain broadcast information within the cell. Meanwhile, the terminal can receive a downlink reference signal (DL RS) during the initial cell search phase to check the downlink channel status.

[0111] A terminal that has completed initial cell search can obtain more specific system information by receiving a physical downlink control channel (PDCCH) and a physical downlink shared channel (PDSCH) according to information included in the PDCCH (S602).

[0112] Meanwhile, when accessing a base station for the first time or when there are no radio resources for signal transmission, the terminal may perform a random access procedure (RACH) for the base station (steps S603 to S606). To this end, the terminal may transmit a specific sequence as a preamble via the Physical Random Access Channel (PRACH) (steps S603 and S605) and receive a response message to the preamble via the Physical Data Channel Control Channel (PDCCH) and the corresponding PDSCH (steps S604 and S606). In the case of a contention-based RACH, a contention resolution procedure (Contention Resolution Procedure) may additionally be performed.

[0113] The terminal that has performed the procedure described above can then perform PDCCH / PDSCH reception (S607) and physical uplink shared channel (PUSCH) / physical uplink control channel (PUCCH) transmission (S608) as general uplink / downlink signal transmission procedures. In particular, the terminal receives downlink control information (DCI) through the PDCCH. Here, DCI includes control information such as resource allocation information for the terminal, and its format varies depending on the purpose of use.

[0114] Meanwhile, the control information that the terminal transmits to the base station via the uplink or that the terminal receives from the base station includes downlink / uplink ACK / NACK (Acknowledgement / Non-Acknowledgement) signals, CQI (Channel Quality Indicator), PMI (Precoding Matrix Indicator), RI (Rank Indicator), etc. In the case of the 3GPP LTE system, the terminal can transmit the above-described control information such as CQI / PMI / RI via PUSCH and / or PUCCH.

[0115] Table 5 shows an example of the DCI format in the NR system.

[0116] DCI Format Utilization 0_0 Scheduling of PUSCH within a cell 0_1 Scheduling of one or multiple PUSCH within a cell, or indicating cell group (CG: cell group) downlink feedback information to the UE 0_2 Scheduling of PUSCH within a cell 1_0 Scheduling of PDSCH within a DL cell 1_1 Scheduling of PDSCH within a cell 1_2 Scheduling of PDSCH within a cell

[0117] Referring to Table 5, DCI formats 0_0, 0_1, and 0_2 may include resource information related to scheduling of PUSCH (e.g., UL / SUL (Supplementary UL), frequency resource allocation, time resource allocation, frequency hopping, etc.), transport block (TB) related information (e.g., MCS (Modulation Coding and Scheme), NDI (New Data Indicator), RV (Redundancy Version), etc.), HARQ (Hybrid - Automatic Repeat and request) related information (e.g., process number, DAI (Downlink Assignment Index), PDSCH-HARQ feedback timing, etc.), multi-antenna related information (e.g., DMRS sequence initialization information, antenna port, CSI request, etc.), power control information (e.g., PUSCH power control, etc.), and the control information included in each DCI format may be predefined.

[0118] DCI format 0_0 is used for scheduling PUSCH in a cell. The information contained in DCI format 0_0 is transmitted after being scrambled with a CRC (cyclic redundancy check) by a C-RNTI (Cell RNTI: Cell Radio Network Temporary Identifier), a CS-RNTI (Configured Scheduling RNTI), or a MCS-C-RNTI (Modulation Coding Scheme Cell RNTI).

[0119] DCI format 0_1 ​​is used to indicate scheduling of one or more PUSCHs in a single cell, or configure grant (CG: configure grant) downlink feedback information to the UE. The information contained in DCI format 0_1 ​​is CRC-scrambled and transmitted using the C-RNTI, CS-RNTI, SP-CSI-RNTI (Semi-Persistent CSI RNTI), or MCS-C-RNTI.

[0120] DCI format 0_2 is used for scheduling PUSCH in a cell. The information contained in DCI format 0_2 is CRC-scrambled and transmitted using C-RNTI, CS-RNTI, SP-CSI-RNTI, or MCS-C-RNTI.

[0121] Next, DCI formats 1_0, 1_1, and 1_2 may include resource information related to scheduling of PDSCH (e.g., frequency resource allocation, time resource allocation, virtual resource block (VRB)-physical resource block (PRB) mapping, etc.), transport block (TB) related information (e.g., MCS, NDI, RV, etc.), HARQ related information (e.g., process number, DAI, PDSCH-HARQ feedback timing, etc.), multi-antenna related information (e.g., antenna port, transmission configuration indicator (TCI), sounding reference signal (SRS) request, etc.), PUCCH related information (e.g., PUCCH power control, PUCCH resource indicator, etc.), and control information included in each DCI format may be predefined.

[0122] DCI format 1_0 is used for scheduling PDSCH in a DL cell. The information contained in DCI format 1_0 is CRC-scrambled and transmitted using C-RNTI, CS-RNTI, or MCS-C-RNTI.

[0123] DCI format 1_1 is used for scheduling PDSCH in a single cell. The information contained in DCI format 1_1 is CRC-scrambled and transmitted using C-RNTI, CS-RNTI, or MCS-C-RNTI.

[0124] DCI format 1_2 is used for scheduling PDSCH in a single cell. The information contained in DCI format 1_2 is CRC-scrambled and transmitted using C-RNTI, CS-RNTI, or MCS-C-RNTI.

[0125] Ambient Internet of Things (A-IoT)

[0126] IoT has recently attracted a lot of attention in the wireless communications field, and it is expected that more things will be interconnected to improve productivity efficiency.

[0127] Most existing wireless communication devices are powered by batteries that require manual replacement or recharging. Therefore, powering all IoT devices with these batteries is impossible, leading to high maintenance costs and serious environmental impacts.

[0128] To address these challenges, new IoT technologies are needed that support battery-less devices without energy storage capabilities, or devices with energy storage capabilities that do not require manual replacement or recharging. As one type of application, most industries currently rely primarily on barcodes and RFID (radio frequency identification). However, their limited read range (a few meters) and lack of interference management systems can lead to serious interference between RFID readers and capacity issues, making it difficult to support large-scale networks with seamless RFID coverage.

[0129] 3GPP is discussing a new IoT technology called Ambient IoT. Ambient IoT technology can enable connections and / or device densities orders of magnitude higher than existing 3GPP IoT technologies, while offering complexity and power consumption orders of magnitude lower than existing 3GPP LPWA (low power wide area) technologies, such as narrow band (NB)-IoT and LTE-MTC (machine type communication).

[0130] FIG. 7 illustrates an ambient IoT device architecture in a wireless communication system to which the present disclosure can be applied.

[0131] - Antenna: The antenna may be shared or separate for the radio frequency (RF) energy harvester and receiver / transmitter.

[0132] - Matching network: The matching network matches the impedance between the antenna and other components (including RF energy harvester and receiver-related blocks).

[0133] - RF energy harvester: The RF energy harvester may include a rectifier that converts an RF signal (i.e., alternating current (AC)) into direct current (DC).

[0134] - Energy storage (e.g., capacitor): Stores energy harvested from RF energy harvesters.

[0135] - Power Management Unit (PMU): The PMU manages the storage of energy in the energy harvester and the supply of power to the active component blocks that require power supply.

[0136] - (Digital) BB (balanced-balanced) logic: BB logic includes functional blocks such as encoder, decoder, and controller.

[0137] - Memory: Memory can include two types of memory: i) non-volatile memory (NVM), such as electrically erasable programmable read-only memory (EEPROM), for permanently storing device IDs, etc., and 2) registers, for temporarily storing information necessary for operation only while energy is present in the energy storage.

[0138] - Clock generator: The clock generator provides the required clock signal(s). Here, the clock signal is a periodic signal used for timing and synchronization. In on-off-keying (OOK) modulation, the time for transmitting a bit (0 or 1) is determined by the chip duration, and this chip duration is precisely controlled by the clock signal and can be defined as a multiple of the clock period, for example. In other words, based on the clock signal, a TARI (Type A Reference Interval) for setting a time interval that serves as a reference for communication can be determined, and based on the TARI, the chip duration can be determined.

[0139] The receiving related blocks include:

[0140] - RF band pass filter (BPF) to improve selectivity: RF BPF may not exist depending on the implementation.

[0141] - RF envelope detector: The RF envelope detector converts the RF signal to baseband.

[0142] - BB low-pass filter (LPF): The BB LPF can improve the quality of the input signal to the comparator by filtering out harmonics and high-frequency components. The BB LPF may not be present depending on the implementation.

[0143] - Comparator: The comparator determines whether the input signal is high or low.

[0144] The receiving related blocks include:

[0145] - Backscatter modulator: The backscatter modulator modulates the backscatter signal into a signal transmitted from the BB logic by switching the impedance.

[0146] Figure 7 illustrates a device with a peak power consumption of ~1 μW, no reader-to-device (R2D) (i.e., receiving) or device-to-reader (D2R) (i.e., transmitting) amplification within the device, and where the device's D2R transmission backscatters (i.e., uses the energy of the received CW to transmit a signal) against an externally provided carrier wave (CW).

[0147] Although not shown in FIG. 7, for devices with peak power consumption of ~ hundreds of μW and R2D or D2R amplification within the device, a reflection amplifier and / or a low noise amplifier (LNA) may be further included to amplify at least one of the R2D / CW2D (Carrier-wave, or carrier-wave node, to device) and D2R.

[0148] Additionally, although not shown in FIG. 7, if the D2R transmission of the device is generated internally by the device, the transmission-related blocks of FIG. 7 may be replaced with blocks for generating and transmitting the following D2R signal.

[0149] - Transmission modulator: The transmission modulator modulates baseband bits according to a modulation method.

[0150] - Digital-to-analog converter (DAC): A DAC converts a digital signal into an analog signal.

[0151] - Low pass filter (LPF): LPF filters out unwanted signals.

[0152] - Mixer: The mixer upconverts the baseband signal to the RF range.

[0153] - Local oscillator (LO): LO generates the carrier frequency.

[0154] - Frequency locked loop (FLL) / phase-locked loop (PLL): Can be used for frequency synthesis, but may not be present depending on the implementation.

[0155] - Power amplifier (PA): The PA amplifies the transmission signal.

[0156] Below, we describe solutions for ambient IoT.

[0157] A-IoT processing time can be defined by the following timing relationship:

[0158] TR2D_min: Minimum time between an R2D transmission and the corresponding D2R transmission.

[0159] TD2R_min: Minimum time between a D2R transmission and its corresponding R2D transmission.

[0160] TD2R_max: Maximum time between a D2R transmission and its corresponding R2D transmission.

[0161] TR2D_R2D_min: Minimum time between two different consecutive R2D transmissions to the same A-IoT device.

[0162] TD2R_D2R_min: Minimum time between two different consecutive D2R transmissions from the same A-IoT device.

[0163] 1. R2D (reader-to-device)

[0164] 1) R2D waveform, modulation, and numerology

[0165] Dedicated physical broadcast channels (e.g., PBCH-like) and reference signals including DMRS, PTRS (phase tracking reference signal), and CSI-RS / TRS may not be considered for R2D.

[0166] An OFDM-based OOK waveform with a subcarrier spacing (SCS) of 15 kHz is considered. For this waveform, the start of the R2D transmission from the reader's perspective can be assumed to be aligned with the boundary of an NR OFDM symbol (including the CP) for in-band / guard-band operation. Both CP-OFDM and DFT-s-OFDM are possible to generate this waveform. Both CP-OFDM (cyclic prefix-OFDM) and DFT-s-OFDM (DFT-spread OFDM) are possible when M=1, i.e., using On-off keying (OOK)-1 or OOK-4 for single-chip transmission per OFDM symbol. DFT-s-OFDM is possible when M>1, i.e., using OOK-4 for M-chip transmission per OFDM symbol.

[0167] 2) PRDCH (physical reader-to-device channel)

[0168] For R2D, the PRDCH can be defined as the sole physical channel. The PRDCH can carry all upper-layer payloads (including system information, if defined) and L1 R2D control information, if defined. For example, if no L1 R2D control information is transmitted via the PRDCH, a PRDCH transmission carrying only R2D data is also possible.

[0169] 3) R2D timing

[0170] An R2D timing acquisition signal (R-TAS) preceding the PRDCH may be included at least for timing acquisition, and the R-TAS may indicate the start of an R2D transmission in the time domain. The structure of the R-TAS using a preamble is being discussed, and may include a start-indicator part that provides the start of an R2D transmission and a clock-acquisition part that is used to determine the OOK chip duration of a subsequent PRDCH transmission. Here, the preamble may not be part of the PRDCH.

[0171] The R-TAS start-indicator part is not included in TD2R_min, and an ON / OFF pattern (i.e., high / low voltage transmission) can be applied. An ON-OFF transmission based on energy / edge detection can be considered for the R-TAS start-indicator part. In this case, a single ON-OFF transmission or multiple ON-OFF transmissions can be included. Here, ON and OFF can have the same or different time intervals. Alternatively, an ON-OFF sequence-based design consisting of a predefined sequence for detecting the R-TAS start-indicator part based on digital correlation can be considered.

[0172] The clock-acquisition portion is based on OOK without line coding, and the device may include rising / falling edges including at least two rising or two falling edges to determine the OOK chip time interval.

[0173] To determine or induce the end of a PRDCH transmission, information may be transmitted via implicit / explicit L1 R2D control information or a postamble may be included at the end of the PRDCH.

[0174] 4) R2D scheduling

[0175] For R2D reception, the device may explicitly / implicitly indicate to the device via the PRDCH the ID associated with the device(s) for R2D reception (potentially including all devices (if supported)).

[0176] 2. D2R (device-to-reader)

[0177] 1) Waveform and modulation

[0178] Reference signals, including DMRS, PTRS, and SRS, may not be considered for D2R. Additionally, CSI feedback and autonomous scheduling requests (SRs) may not be considered for L1 (layer-1) D2R control information.

[0179] For D2R by backscattering, the waveform can be provided by a CW (carrier wave). The D2R baseband signal (distinguished from the inner or outer carrier wave) can be non-OFDM.

[0180] The following D2R baseband modulations are discussed for all devices:

[0181] - OOK

[0182] - BPSK (binary phase shift keying)

[0183] - BFSK (binary frequency shift keying), MSK (minimum shift keying)

[0184] 2) PDRCH (physical device-to-reader channel)

[0185] For D2R, the physical channel PDRCH can carry upper layer payload, responses sent from the device to the leader during contention-based access procedures, and L1 D2R control information (if defined).

[0186] 3) D2R timing

[0187] A D2R timing acquisition signal (D-TAS) preceding each PDRCH may be included at least for timing acquisition purposes and may indicate the start of a D2R transmission in the time domain. A D-TAS structure using a preamble is being discussed, and a binary signal may be considered. Here, the preamble may not be part of the PDRCH.

[0188] To ensure that the leader obtains the end of a PDRCH transmission, a D2R postamble may be included immediately after the PDRCH or may be based on control information.

[0189] 4) D2R scheduling

[0190] For D2R scheduling, the following information can be explicitly / implicitly indicated to the device via the PRDCH:

[0191] - Time domain resources

[0192] - Frequency domain resources

[0193] - MCS-like information

[0194] - Chip duration

[0195] - ID associated with the device(s)

[0196] - Repeat

[0197] - Information about midamble (if supported)

[0198] 3. Overall procedure

[0199] FIG. 8 illustrates an overall procedure between an A-IoT device and a reader in a wireless communication system to which the present disclosure can be applied.

[0200] - Step A: A-IoT Paging. Based on the service request, the leader transmits an A-IoT paging message indicating the device(s) that should respond.

[0201] Here, the A-IoT paging function can use A-IoT paging messages to indicate the device(s) that require a response.

[0202] An identifier may be included in this trigger message within the A-IoT paging message to identify the device / device group. Additionally, the A-IoT paging message may include additional information that allows the device to determine the resources to use in the D2R response message.

[0203] A leader can transmit multiple (subsequent) A-IoT paging messages related to the same service request in the core network (CN). Duplicate responses from devices to the same service request must be avoided. Information to avoid such duplicate responses from devices to the leader can be included in the A-IoT paging message. Based on this information, the device can decide whether to skip sending a response to the A-IoT paging message.

[0204] - Step B: D2R data (device ID) transmission. The triggered A-IoT device(s) perform device ID transmission with or without the A-IoT random access procedure.

[0205] The A-IoT random access procedure is used by A-IoT devices to access the network for data transmission. The A-IoT random access procedure is triggered by the leader and can trigger access for a single A-IoT device, a group of A-IoT devices, or all A-IoT devices within the leader's coverage area.

[0206] Slotted-ALOHA (slotted-additive links on-line Hawaii area) can be used as an A-IoT random access procedure.

[0207] After the A-IoT device considers contention resolution successful when contention-based random access is used, or when contention-free access is used, the A-IoT device may perform upper layer data transmission with the leader (e.g., device ID and / or other upper layer data, if any).

[0208] In the event of a D2R data transmission failure and contention-based random access contention resolution failure, the A-IoT device is supported to re-access at another opportunity (i.e., random access retry) controlled / provided by the leader. Note that the A-IoT device cannot autonomously re-access, and re-access is always controlled by the leader. The leader can use an optional explicit R2D failure / success feedback indication to determine whether the A-IoT device should re-access.

[0209] - Step C1: Possible R2D data transmission (e.g. command transmission).

[0210] - Step C2: Possible D2R data transmission (e.g., response to a command).

[0211] Subsequent R2D data transmissions following a D2R data transmission can be considered as not requiring retransmission of the D2R data. In the event of a D2R data transmission failure, the A-IoT device can follow the leader's subsequent R2D instructions. For example, the leader can repeat an R2D upper-layer "command" to trigger the A-IoT device to resend the same D2R upper-layer "response" (i.e., the A-IoT device can transmit a D2R following the received R2D).

[0212] The A-IoT MAC layer can only support simplified segmentation and can support a maximum TB size of approximately 1000 bits in both R2D and D2R directions.

[0213] Additionally, A-IoT devices can report their energy status to the leader. For example, an A-IoT device can report a 1-bit energy status indicator to the leader in a D2R message. The leader can consider this indicator in the remaining / follow-up procedures. For example, the leader may not transmit subsequent messages for a while, or the leader may not take any action.

[0214] From a higher-level perspective, an "AS (access stratum) ID" can be used for D2R scheduling and R2D reception purposes. Any ID used in the first D2R message can be reused as the "AS ID," or the leader can assign this "AS ID" to an A-IoT device.

[0215] 4. RAN Architecture

[0216] FIG. 9 illustrates a logical system architecture in a wireless communication system to which the present disclosure can be applied.

[0217] The RAN architecture for supporting ambient IoT can support a logical system architecture for topology 1 as in Fig. 9(a) and a logical system architecture for topology 2 as in Fig. 9(b).

[0218] - A-IoT device: A device that supports ambient IoT.

[0219] - A-IoT RAN: Hosts specific functions for A-IoT as part of the RAN's functionality.

[0220] - A-IoT radio: Radio interface between A-IoT devices and A-IoT RAN nodes in topology 1, and between A-IoT devices and A-IoT enabled UEs in topology 2.

[0221] - A-IoT CN: Hosts specific functions for A-IoT in terms of CN's functional aspects.

[0222] - XX Interface: Interface between A-IoT RAN / A-IoT supporting gNB and A-IoT CN where specific A-IoT specific functions are performed.

[0223] - Common reader function: Ability to communicate with A-IoT devices via A-IoT wireless.

[0224] - A-IoT RAN node functions: Functions including, for example, control of A-IoT radio resources used for A-IoT devices.

[0225] FIG. 9(a) shows that both the common reader function and the A-IoT RAN node function can be supported by the A-IoT RAN node. Conversely, FIG. 9(b) shows that the common reader function is supported by the A-IoT-enabled UE, and the A-IoT RAN node function can be supported by the A-IoT-enabled gNB.

[0226] 5. Information exchanged between the A-IoT CN (core network) and the A-IoT RAN (radio access network).

[0227] Information about A-IoT service types (e.g., inventory, commands) can be directed to the leader from the CN.

[0228] 1) Inventory: This refers to the service that the network provides to discover and obtain identifiers of A-IoT devices.

[0229] A-IoT CN can transmit inventory for a single device, a group of devices, or all devices.

[0230] An inventory request transmitted from an A-IoT CN to an A-IoT RAN may include:

[0231] - A-IoT device identification (to find a single device, a group of devices, or all devices)

[0232] - The scope of the inventory request (e.g. the specific area where the inventory will be triggered)

[0233] Multiple individual A-IoT device IDs (one ID per device) can be provided to the A-IoT CN via a single inventory report.

[0234] 2) Command: This refers to the service (e.g., read, write, etc.) that the network provides to send work instructions to A-IoT devices.

[0235] A-IoT CN can transmit commands to a single device.

[0236] A method for transmitting and receiving synchronous signals in an ambient IoT (A-IoT or AmIoT: ambient IoT) system.

[0237] In the present disclosure, a carrier wave (CW) transmitted by a base station (e.g., gNB) or an intermediate node (e.g., an A-IoT enabled UE, etc.) may include a CW for energy harvesting (EH) purposes and / or a CW for backscattering (BSC) purposes. That is, the CW described in the present disclosure may be applied to one of the two CW purposes in a limited manner, or may be applied to both CW purposes in a common manner. In addition, in the present disclosure, the NR system may be replaced with a (5G and / or 6G) wireless communication system (or a mother system or a coexisting communication system, etc.), and the gNB may mean a base station of the NR system or the wireless communication system, and the UE may mean a terminal of the NR system or the wireless communication system. In this disclosure, for convenience of explanation, only UE is described as an intermediate node, but it can be extended to other types of nodes such as IAB (Integrated access-backhaul) and NCR (Network-controlled Repeater).

[0238] FIG. 10 is a diagram illustrating A-IoT operation in a wireless communication system to which the present disclosure can be applied.

[0239] Figure 10(a) illustrates the operation of Topology 1. The gNB transmits CW (for BSC purposes) using frequency resource #A, and the AmIoT device receiving the CW can perform backscattering to transmit a backscattered signal (BSS). The BSS can have a frequency gap (F-gap: frequency gap) with the CW in the frequency domain, and can be transmitted in a different band from the NR UL transmission.

[0240] Figure 10(b) illustrates the operation of topology 2. UE 1, as an intermediate node (IN), transmits CW (for BSC purposes) using frequency resource #A, and the AmIoT device receiving it can perform backscattering to transmit a backscattered signal (BSS). The BSS can have a frequency gap (F-gap: frequency gap) with the CW in the frequency domain, and can be transmitted in a different band from the NR UL transmissions from UE 1 and UE 2.

[0241] Hereinafter, the methods proposed in this disclosure can be commonly applied to both topologies 1 and 2. Furthermore, for convenience of explanation in this disclosure, the gNB and UE1 as an IN are referred to as a reader. Furthermore, this disclosure can be commonly applied to both cases, where the leader receiving the BSS directly generates and transmits a CW, or where the node transmitting the CW is a separate node from the leader.

[0242] Additionally, the ambient IoT BS (base station) (e.g., reader) used in the present disclosure may correspond to a base station (e.g., gNB) in topology 1, and may correspond to a specific UE (e.g., UE 1 in FIG. 10(b)) in topology 2. Additionally, the ambient IoT device (e.g., tag) used in the present disclosure may be interpreted as an ambient IoT device in both topology 1 and / or topology 2.

[0243] Hereinafter, the present disclosure proposes a structure of a DL synchronization signal and / or an UL synchronization signal applicable to an A-IoT system and a method for transmitting and receiving the same.

[0244] Hereinafter, in the present disclosure, DL transmission may mean R2D transmission, and UL transmission may mean R2D transmission.

[0245] Hereinafter, in the present disclosure, a DL / UL synchronization signal may refer to a DL / UL preamble (e.g., an R2D / D2R timing acquisition signal) transmitted immediately before transmission of a DL / UL physical channel and / or a signal for frame sync acquisition that may be transmitted periodically.

[0246] In this disclosure, ' / ' means 'and', 'or', or 'and / or' depending on the context.

[0247] Example 1: DL synchronization signal design / generation method

[0248] - The time period (duration) of data_0 (i.e., data representing 0) / data_1 (i.e., data representing 1) to be used for the DL synchronization signal can be set / indicated as a fixed value. Here, the base station can set the duration of data_0 / data_1 to N symbols (e.g., ambient IoT symbols) (N is an integer greater than 0), and include it in the DL synchronization signal (e.g., DL preamble / DL frame-sync). For example, since data_0 is composed of 1 symbol (e.g., ambient IoT symbol) and data_1 is composed of N-1 symbols (e.g., ambient IoT symbols), data_0 / data_1 can be defined as a total of N symbols (e.g., ambient IoT symbols), which can be included in the DL synchronization signal (e.g., DL preamble / DL frame-sync).

[0249] - In addition, the symbol length for data_0 / data_1 may be defined as N symbols (e.g., Ambient IoT symbol) (N is an integer greater than 0). And, a specific sequence consisting of data_0 / data_1 may be defined and transmitted for a DL synchronization signal (e.g., DL preamble / DL frame-sync). For example, data_0 and data_1 may each be defined as one symbol (e.g., Ambient IoT symbol), and a sequence to be used for a DL synchronization signal (e.g., DL preamble / DL frame-sync) may be defined in advance (e.g., a sequence consisting of data_0 / data_1 such as 010111, 101000, etc.).

[0250] - In addition, a method of separately designing the DL preamble and DL frame-sync, which can be considered as DL synchronization signals, can be considered. Here, the DL frame-sync can be defined / configured to have a structure of {delimiter + reference data + Tari_F}, and the DL preamble can have a structure of {delimiter + reference data + Tari_P}. Here, Tari_F and Tari_P can represent a time interval (i.e., a reference interval) that serves as a reference when transmitting a synchronization signal.

[0251] Here, Tari_F = (symbol time interval of reference data) * A can be set, and the A value can be defined as a fixed value. In addition, Tari_P = (symbol time interval of reference data) * B can be set. The B value can be variable for transmitting backscattering link frequency (BLF) information, and can be defined to have a different value from A (for example, B is greater than A, or B is less than A). The reference data can be data_0 and / or data_1. In addition, Tari_F can be defined as described above, and can be defined in the form of Tari_P = Tari_F * C. Here, the C value can be set to a value other than 1 for the purpose of distinguishing the Tari_P length from the Tari_F length.

[0252] In addition, the relationship between the above A and B values ​​can be specifically defined. For example, assuming a situation where there are more UL transmissions than DL transmissions, DL clock information can be transmitted with Tari_F, and UL clock information can be transmitted with Tari_P, so a condition of A>B can be added. In addition, various B values ​​can be defined for various BLF instructions. For example, <B 조건으로 Tari_F 및 / 또는 Tari_P가 결정될 수 있으며, 추가적으로 A<B1<B2<B3<쪋<Bn 과 같이 n개의 B 값은 항상 A보다 크도록 설정될 수도 있다. 또한, 기본적으로 A>Tari_F and / or Tari_P can be determined as a condition of A B by default, and additionally, B1 <B2<, …<Bn<A 과 같이 n개의 B 값은 항상 A보다 작도록 설정될 수도 있다.

[0253] - Additionally, a condition can be added to allow the DL data to have a different value from the DL encoding perspective (i.e., to check for communication errors (violations)).

[0254] Here, a condition may be set such that the lengths of Tari_F and Tari_P can be distinguished from the lengths of data_0 and / or data_1. For example, it may be set such that Tari_F (or Tari_P) > max(length of data_0, length of data_1) is satisfied.

[0255] Alternatively, if data_0 and / or data_1 to be used in DL are encoded in the form of OOK (on-off keying), the symbol power level or pulse of data_0 may be composed of 1 symbol having the form of 'off-on', and the symbol power level or pulse of data 1 may be composed of 1 symbol having the form of 'on-off'.

[0256] Here, assuming the A value of Tari_F to be 2, Tari_F can be defined as Tari_F = (symbol time interval of reference data) * 2. The symbol power level or pulse of Tari_F can be set / defined to be distinguished from the form in which on-off and / or off-on is repeated (i.e., on-off-on-off and / or off-on-off-on), such as {off-on-on-on} or {off-off-on-on} or {on-off-on-on} or {on-on-off-on}.

[0257] In addition, when Tari_F and Tari_P are configured as described above, if the information bits of DL data with the same encoding (e.g., Miller coding (MC)) follow immediately thereafter (e.g., if Tari_F / P ends with on-on and is immediately followed by data_1, it will be in the form of on-on-on-off, which may be the same as the Tari_F and / or Tari_P defined above), it may not be easy for the A-IoT device to distinguish between the synchronization signal and the information bits. Therefore, dummy data_0 can be appended to Tari_F and / or Tari_P to indicate that it is encoding for DL ​​preamble / DL frame-sync, and it can be defined / set so that the information bits of DL data follow thereafter. Applying this, the DL frame-sync can be defined / set to have a structure of {delimiter + reference data + Tari_F + dummy data_0}, and the DL preamble can be defined / set to have a structure of {delimiter + reference data + Tari_P + dummy data_0}. Here, the dummy data may be data_1 instead of data_0. In addition, the reference data and / or the dummy data may be set in multiple numbers through a combination of data_0 and / or data_1. For example, the DL preamble / DL frame-sync #1 can be defined / set as {delimiter + N*data_0 + Tari_F / P + M*dummy data_0}, and the DL preamble / DL frame-sync #2 can be defined / set as {delimiter + 2N*data_0 + Tari_F / P + 2M*dummy data_0}.

[0258] Example 2: Method for setting / instructing information using a DL synchronization signal

[0259] Backscattering link frequency (BLF) information (e.g., information for determining the transmission speed of a backscattering response signal) can be set / indicated via a DL synchronization signal. For example, BLF information can be indicated based on the length of Tari_P of the proposed DL preamble. That is, by providing different lengths of Tari_P of the DL preamble, the A-IoT device can determine the BLF. Alternatively, the BLF value can be explicitly set / indicated via a message / command in the DL payload. In this case, when the BLF value is indicated via the DL payload, the DL preamble is not separately defined, and only the DL synchronization signal (e.g., DL frame-sync) can be defined.

[0260] Additionally, the value of the DL symbol length and / or the value of the UL symbol length can be set / indicated via the DL synchronization signal. For example, if data_0 and / or data_1 to be used for DL ​​are encoded in the OOK format, information for determining the length of 1 symbol carrying data_0 and / or data_1 (e.g., chip duration) can be included in the DL synchronization signal.

[0261] For example, Tari_P and / or Tari_F may be designed to include DL symbol length (e.g., DL clock information) and / or UL symbol length (e.g., UL clock information). Here, the DL clock information may provide the length of DL data_0 and the length of DL data_1 together (similar to reference time calibration (RTCal) of RFID). The UL clock information may indicate a BLF value (e.g., a combination of TRCal and divide ratio (DR)) (similar to tag to reader calibration (TRCal) of RFID), or may include a frequency shift (e.g., via subcarrier modulation). Alternatively, the DL symbol length value and / or the UL symbol length value may be explicitly set / indicated via a message / command in the DL payload.

[0262] In addition, instead of defining both a DL preamble and a DL frame-sync for the DL synchronization signal, a method of introducing only one DL synchronization signal can be considered. Here, the DL synchronization signal can be defined to transmit the DL clock information and / or the UL clock information simultaneously. Alternatively, the DL clock information can be transmitted by default in the DL synchronization signal, and UL clock information can be additionally indicated according to base station settings / instructions. Alternatively, only the DL clock information can be transmitted in the DL synchronization signal, and the UL clock information can be transmitted in the form of a message / command in a separate DL payload.

[0263] In addition, in the A-IoT system, the R2D preamble can be defined as a multiple of the NR OFDM symbol length (or a multiple of the M value, which can be defined as the number of chips in the A-IoT system). For example, when 15 kHz SCS is used, the length of the R2D preamble can be defined as a multiple of one NR OFDM symbol length including the CP (cyclic prefix) length (i.e., 66.6 us + 4.69 us = 71.35 us). In addition, the leader can set / instruct the device to start transmitting the PRDCH immediately following the R2D preamble, where the transmission timing gap can be defined as a multiple of the NR OFDM symbol length (or a multiple of the M value, which can be defined as the number of chips in the A-IoT system). Setting it as a multiple of the NR OFDM symbol length in this way can have an advantage in terms of coexistence with NR.

[0264] Example 2A: Method for setting / instructing information through midamble

[0265] An operation of transmitting a midamble to maintain timing synchronization (i.e., sampling frequency offset (SFO) tracking) during R2D (Reader to Device) and / or D2R (Device to Reader) transmissions may be considered. Here, additional information may be indicated through the midamble.

[0266] When transmitting R2D, parameter values ​​set / indicated in the previously transmitted preamble can be changed through the midamble. For example, specific information (e.g., BLF, D2R symbol length, R2D symbol length, coding rate, chip rate, R2D transmission length, D2R transmission delay (for changing frequency resources of CW), etc.) can be set / indicated through the preamble. Thereafter, the leader can set / indicate the corresponding information (e.g., BLF, D2R symbol length, R2D symbol length, coding rate, chip rate, R2D transmission length, D2R transmission delay (for changing frequency resources of CW), etc.) through the subsequent midamble independently from the values ​​transmitted in the preamble. For example, if a midamble is included for timing synchronization during transmission of the same data (e.g., the same transport block (TB)), the BLF value after the midamble may be set independently (i.e., newly set / indicated) from the BLF value before the midamble. Alternatively, the reader may set / indicate a subset of the values ​​transmitted in the preamble for that information through the subsequent midamble. Additionally, only the 'delta' value (i.e., only the difference / step) of the values ​​transmitted in the preamble may be signaled in the midamble. For example, it is assumed that the values ​​BLF1 < BLF2 < BLF3 < BFL4 < ... are pre-set / defined for BLF. Here, if the leader indicates BLF2 through the preamble, and then the leader indicates '+1' as the delta value through the midamble, the A-IoT device can determine that BLF3, which is one larger than BLF2, has been indicated.Alternatively, if the leader indicates '0' as the delta value through the midamble, the A-IoT device can determine that it is instructed to maintain the same value as the existing BLF2 (i.e., hold). Alternatively, if the leader indicates '-1' as the delta value through the midamble, the A-IoT device can determine that it is instructed to use BLF1, which is one less than BLF2. In addition, the midamble indicated by the leader can also indicate whether the value set / instructed in the previous preamble will be maintained as is or revert to a pre-set / defined fallback value (for example, in the case of BLF, BLF1 can be set as the fallback value).

[0267] As described above, when additional information is provided via the midamble, the behavior of the A-IoT device may vary depending on the type (or capability) of the device. For example, active devices (e.g., devices that generate signals for D2R transmissions) may be configured to receive information provided via the preamble and / or midamble of an R2D transmission and then apply the information to their respective D2R transmissions during subsequent D2R transmissions. On the other hand, passive devices must perform a D2R transmission via backscattering immediately after receiving an R2D transmission. Therefore, in order to provide additional information via the readamble when performing an R2D transmission, the leader may be configured to perform the R2D transmission, including the midamble, with a sufficient timing gap to allow the A-IoT device to complete the preceding D2R transmission.

[0268] Meanwhile, a method for the leader to change the R2D frequency resource during R2D transmission may be considered. Here, when the leader instructs the device to change the R2D frequency resource, a midamble (and / or preamble) may be transmitted at the end of the R2D transmission before the frequency resource change to set / instruct the device to provide subsequent R2D frequency resource information.

[0269] Additionally, based on the device's behavior of attaching a midamble during a D2R transmission, the device can implicitly inform the reader that it is transmitting specific data (e.g., the same transmission block) in segments. For example, during a D2R transmission, a midamble may be attached to each segmented data, or a midamble may be attached once to the original data before being divided.

[0270] The proposed methods using the aforementioned midamble can be equally applied to preambles and / or frame synchronization. Furthermore, the methods proposed for D2R can also be applied to R2D, and vice versa.

[0271] Example 3: Method for setting / indicating a delimiter for a DL synchronization signal

[0272] A symbol duration can be defined during which an A-IoT BS (e.g., a leader) does not transmit anything before transmitting a DL preamble / DL frame-sync. Here, the symbol duration can be defined as a delimiter for a DL synchronization signal. Here, the length for the delimiter needs to be defined so as to be distinguishable from a DL encoded symbol. For example, the length for the delimiter can be defined as an A-IoT symbol that is larger than the data_0 symbol length of the encoded symbol, or as an NR CP-OFDM symbol (i.e., data_0 symbol length + additional symbols), or as an NR slot based on a specific SCS interval value (e.g., 15 kHz SCS).

[0273] Also, instead of defining the delimiter as not transmitting anything, it may be considered to always transmit at a high power level or in the form of an on pulse. For example, data_1 (or always ON, or a high power level section in case of OOK) may be set / defined to be used as the delimiter, so that it may be advantageous in terms of transmitting energy to the A-IoT device. In this case, as mentioned above, the length for the delimiter needs to be defined so that it can be distinguished from the DL encoded symbol. For example, the length for the delimiter may be defined as an A-IoT symbol that is larger than the data_1 symbol length of the encoded symbol, or as an NR CP-OFDM symbol (i.e., data_1 symbol length + additional symbols), or as an NR slot based on a specific SCS interval value (e.g., 15 kHz SCS).

[0274] In addition, the delimiter may be set / defined to have multiple values. For example, when applying the PR-ASK (phase-reversal amplitude shift keying) modulation method, since the amplitude change occurs only in the phase transition section, it may be defined to have multiple values ​​to change the amplitude. Specifically, the delimiter structure may be defined as {transmitting data_0 for X ms and transmitting data_1 for Y ms} or {transmitting data_1 for X ms and transmitting data_0 for Y ms}. Here, considering any ASK (amplitude shift keying) method, only one of the above structures may be supported, or a method in which it is set / selected / indicated in combination with PR-ASK may be considered. Here, the X value and the Y value need to be set so as to be distinguishable from the encoded symbol, and for example, the X value may be defined relatively short compared to the Y value.

[0275] Example 4: Timing setting / instruction method for an intermediate node (IN) to transmit a DL synchronization signal

[0276] In topology 2 illustrated in Fig. 10(b), UE 1 operates as an intermediate node (IN). Here, when IN, as a leader, transmits a DL synchronization signal (e.g., preamble / frame-sync) for an A-IoT device (e.g., tag), the following method can be applied.

[0277] 1) When IN is in a connected state, based on the UL synchronization value set for NR UL transmission to the base station (e.g., gNB), IN can transmit a DL synchronization signal by applying a UL timing advance (TA: timing advance) value to a DL synchronization signal (e.g., preamble / frame-sync).

[0278] Alternatively, when the IN is in a connected state, a specific TA offset may be additionally set / indicated from a base station (e.g., gNB) via a random access procedure (or a random access channel (RACH) procedure) or a TA command field within a MAC control element (CE). In this case, the IN may transmit a DL synchronization signal based on a value obtained by additionally applying the corresponding TA offset to the UL TA value acquired by the IN.

[0279] Here, the base station (e.g., gNB) can set / instruct the IN about the transmission timing of the DL synchronization signal and the UL resources for transmitting the DL synchronization signal through higher layer signaling (and / or dynamic instruction through DCI, etc.). Alternatively, the base station (e.g., gNB) can set / instruct a specific timing window (or timer) through higher layer signaling, and the IN can transmit the DL synchronization signal within the timing window (or timer) at its own discretion. In addition, when the IN sets / instructs the tags about the transmission timing, the IN can also reflect (or instruct based on) the UL TA value acquired by the IN (or the UL TA offset value set / instructed by the gNB).

[0280] 2) When IN is in idle / inactive state, the UL TA value acquired by IN does not exist. Therefore, the base station (e.g., gNB) can set / indicate the A-IoT-specific UL TA (or UL TA offset) value through upper layer signaling (e.g., SIB (system information block), etc.). In this case, IN can transmit the DL synchronization signal based on the value.

[0281] Alternatively, when the time for transmitting a DL synchronization signal approaches, the IN in an idle / inactive state can perform a RACH procedure to obtain a UL TA value. Thereafter, the IN can transmit a DL synchronization signal based on the UL TA value (and / or a TA offset value set / indicated by the base station).

[0282] Here, the base station (e.g., gNB) can set / instruct the IN about the transmission timing of the DL synchronization signal and the UL resources for transmitting the DL synchronization signal through higher layer signaling (and / or dynamic instruction through DCI, etc.). Alternatively, the base station (e.g., gNB) can set / instruct a specific timing window (or timer) through higher layer signaling, and the IN can transmit the DL synchronization signal within the timing window (or timer) at its own discretion. In addition, when the IN sets / instructs the tags about the transmission timing, the IN can also reflect (or instruct based on) the UL TA value acquired by the IN (or the UL TA offset value set / instructed by the gNB).

[0283] 3) In addition, in a situation where IN, as a leader, must perform a RACH procedure (i.e., a random access procedure) due to a mismatch in UL synchronization with a base station (e.g., a gNB) while communicating with other A-IoT devices (e.g., tags), the other A-IoT devices (e.g., tags) may operate as follows.

[0284] An IN that must perform a RACH procedure can set the A-IoT device (e.g., tag)(s) to wait by setting / instructing a specific command (e.g., a hold command) to the A-IoT device (e.g., tag)(s). After the RACH procedure is completed, the IN can set / instruct the A-IoT device (e.g., tag)(s) to resume communication by setting / instructing another command (e.g., a restart command) to the A-IoT device (e.g., tag)(s).

[0285] Alternatively, the A-IoT device (e.g., tag)(s) that understand / determine that no signal is being transmitted from the IN may wait until a predefined window (or a window initially set / instructed by the IN) or timer, etc. expires. If no command or DL ​​synchronization signal is transmitted from the IN until the window or timer expires, the A-IoT device (e.g., tag)(s) may return to the initial waiting state.

[0286] Example 4A: Method for setting / instructing transmission / reception timing when UL TA of an intermediate node (IN) expires

[0287] When an intermediate node (IN) transmits an R2D transmission (e.g., preamble, PRDCH, postamble, etc.) for other A-IoT devices (e.g., tags) as a leader, it is desirable to perform the R2D transmission by applying the UL TA value if the UL TA value of the intermediate node is valid. However, the behavior of the IN needs to be defined when the timer for the UL TA expires and / or the UL TA value is no longer valid, such as when a RACH procedure is performed to acquire a new UL TA but a radio link failure (RLF) occurs. Here, the TA timer for the UL TA defined in the existing NR standard can be reused as the timer for the UL TA. Alternatively, a separate TA timer can be introduced for NR UEs operating as an IN, in which case the validity of the UL TA value can be determined using the newly introduced TA timer.

[0288] Method 1) If there is no longer a valid UL TA value in the IN, the IN may no longer perform R2D transmission. That is, the IN may wait without performing R2D transmission until it acquires a new valid UL TA through a subsequent RACH procedure (i.e., random access procedure).

[0289] However, since the IN may be capable of D2R reception, the IN can continue to perform D2R reception regardless of the validity of the UL TA value. In this way, the IN stores the information received through the D2R reception, and after the IN obtains a valid UL TA value, it can perform the related R2D transmission.

[0290] Alternatively, IN may not perform D2R reception while it is not performing R2D transmission.

[0291] Method 2) Even if the IN no longer has a valid UL TA value, the IN can still perform R2D transmission using the UL TA value that was valid immediately before. That is, the IN can perform R2D transmission using the UL TA value that was valid immediately before until it acquires a new valid UL TA through a subsequent RACH procedure (i.e., random access procedure). In this case, since the IN continues to perform R2D transmission, it can also continue to perform D2R reception.

[0292] Method 3) If there is no longer a valid UL TA value in the IN, the IN can perform R2D transmission by setting the UL TA value to 0 (i.e., setting it to the UL TA value set during the initial RACH procedure).

[0293] Alternatively, a base station (e.g., gNB) may set / indicate a UL TA offset value via upper layer signaling so that it can be used in situations where the UL TA value of IN is invalid. In this case, IN may perform R2D transmission by applying the set / indicated UL TA offset value when the UL TA value is invalid.

[0294] Alternatively, a predefined UL TA offset value can be predefined between the IN and the base station (e.g., gNB) (i.e., predefined in the standard). The IN can perform R2D transmission by applying the predefined UL TA offset value if the UL TA value is invalid.

[0295] Common to the above methods, after the IN acquires a new valid UL TA value through a RACH procedure (i.e., a random access procedure), the IN can perform R2D transmission using the valid UL TA value.

[0296] Additionally, when transmitting a carrier wave (CW) from an IN (e.g., a UE), the UL TA value may be applied to the CW transmission to align the CW transmission timing with the NR OFDM symbol boundary. Therefore, the proposed methods can be similarly applied to the CW transmission timing of the IN.

[0297] Alternatively, the CW transmission timing may not necessarily be aligned with the NR OFDM symbol boundary without causing a significant problem from an energy harvesting perspective. Therefore, when the UL TA of the IN has expired, the proposed methods can be applied for R2D / D2R transmission / reception timing, and TA can be set to 0 and transmitted for the CW transmission timing. In other words, an operation of setting the TA value upon initial access (i.e., setting TA to 0) and transmitting without using the UL TA of the IN as an exception only for the CW transmission timing can be allowed.

[0298] Alternatively, for similar reasons as above, when NR UEs that can operate as INs perform R2D / D2R transmission and reception, they may use the UL TA of the corresponding UEs, but may not use the UL TA of the corresponding UEs when transmitting CW. Afterwards, when the UL TA value of the NR UE operating as INs expires (i.e., when the TA timer expires), the INs may not perform R2D / D2R transmission and reception and may also stop CW transmission.

[0299] Meanwhile, among NR UEs capable of operating as INs, only UEs for which the validity of the UL TA acquired by each UE has been secured can be defined to operate as INs. In other words, among NR UEs capable of operating as INs, only UEs for which the validity of the TA has been confirmed can be defined to perform the role of A-IoT leader as INs.

[0300] In addition, in addition to the validity of the proposed UL TA value, a condition for an NR UE to operate as an IN may be defined. For example, a change in the RSRP (reference signals received power) of the UE and / or a change in the SSB RSRP value for beam selection in the UE may also be considered / applied as a condition for an NR UE to operate as an IN (i.e., a condition for the NR UE to participate in D2R / R2D communication). In addition, the conditions and the validity condition of the proposed UL TA value may be combined to be considered / applied as a condition for an NR UE to operate as an IN. In addition, if any one of the above-described conditions is satisfied (or not satisfied), it may be defined that the NR UE can no longer operate as an IN.

[0301] For example, even if the UL TA of an NR UE operating as IN has not expired, if the RSRP changes beyond a pre-configured / indicated threshold value within a short period of time, the NR UE may be determined to be no longer at the previous location, and thus the UE may be set to no longer be able to operate as IN. As another example, even if the UL TA of an NR UE operating as IN has not expired, if there is no longer an SSB beam index for the NR UE to select, the UE may be determined to be no longer at the previous location, and thus the UE may be set to no longer be able to operate as IN.

[0302] Example 5: Method for setting whether to transmit UL preamble

[0303] A UL preamble for the UL synchronization signal can be defined. Furthermore, depending on specific circumstances, a UL extended preamble may be considered instead. The following is a proposed method for this purpose.

[0304] However, while the present disclosure uses the terms preamble and extended preamble for convenience of explanation, the present disclosure is not necessarily limited thereto. That is, preambles defined as different types may be utilized equally.

[0305] Method 1) When a transmission of an A-IoT device (e.g., a tag) according to a specific command transmitted from an A-IoT BS (e.g., a leader) is completed once, the A-IoT device can transmit the UL transmission including a preamble.

[0306] On the other hand, if the UL transmission of an A-IoT device (e.g., a tag) according to a specific command transmitted from a leader is not completed in one time and multiple UL transmissions are required, the A-IoT device may transmit including an extended preamble in the multiple UL transmissions. Alternatively, the A-IoT device may transmit including the extended preamble only in the first UL transmission and include the preamble in the remaining UL transmissions. Alternatively, the A-IoT device may transmit including the preamble in the multiple UL transmissions. Alternatively, the A-IoT device may transmit including the preamble in the first UL transmission and omit the preamble in the remaining UL transmissions.

[0307] In addition, in a situation where multiple UL transmissions of an A-IoT device are required, if the timing gap between the multiple UL transmission points is less than (or less than or equal to) a pre-set / defined timer, the A-IoT device (e.g., a tag) may transmit the UL transmission including a preamble. On the other hand, if the timing gap between the multiple UL transmission points is greater than (or greater than or equal to) a pre-set / defined timer, the A-IoT device (e.g., a tag) may transmit the UL transmission including an extended preamble.

[0308] Alternatively, a method based on the RSRP value of an A-IoT device (e.g., a tag) may also be considered. For example, if the RSRP value of an A-IoT device (e.g., a tag) when transmitting UL is less than or equal to a threshold (TH) that is set / defined in advance, the A-IoT device may transmit (or transmit including the preamble) with an extended preamble when transmitting the UL. On the other hand, if the RSRP value of an A-IoT device (e.g., a tag) when transmitting UL is greater than a TH that is set / defined in advance, the A-IoT device may transmit (or transmit omitting the preamble) with a preamble when transmitting the UL.

[0309] 2) Whether or not to transmit a preamble can be determined depending on the accuracy of the transmission time of the A-IoT device (e.g., tag).

[0310] For example, when an A-IoT BS (e.g., a leader) transmits a command to an A-IoT device (e.g., a tag), if the A-IoT device precisely sets / instructs the transmission timing, the A-IoT device can transmit UL transmission omitting the (extended) preamble. On the other hand, if an A-IoT BS (e.g., a leader) transmits a command to an A-IoT device (e.g., a tag), and the A-IoT device can freely determine the transmission timing (within a range satisfying predefined conditions), the A-IoT device can transmit UL transmission including the (extended) preamble.

[0311] In addition, if the transmission time indicated by the A-IoT BS (e.g., the leader) is instructed to be more than a certain value away from the command of the A-IoT BS (i.e., if the scheduling gap is set / instructed to be more than a certain value (e.g., the TH value set / instructed by the A-IoT BS)), the A-IoT device (e.g., the tag) can transmit including the (extended) preamble during UL transmission. On the other hand, if the transmission time indicated by the A-IoT BS (e.g., the leader) is instructed to be within a certain value from the command of the A-IoT BS (i.e., if the scheduling gap is set / instructed to be less than the certain value), the A-IoT device (e.g., the tag) can transmit UL transmission omitting the (extended) preamble.

[0312] In other words, when an A-IoT BS (e.g., a leader) indicates a UL transmission timing of an A-IoT device (e.g., a tag), it is assumed that the transmission timing is after a specific timing gap (e.g., T1). Here, if the timing gap value is greater than or equal to a threshold value that is set / indicated in advance, the A-IoT device can transmit including an (extended) preamble during UL transmission. On the other hand, if the timing gap value is less than the threshold value that is set / indicated in advance, the A-IoT device can transmit omitting the (extended) preamble during UL transmission.

[0313] Additionally, in the proposed method described above, if a specific situation is satisfied, the A-IoT device may be configured / defined to transmit including an extended preamble during UL transmission, and in the opposite situation, the A-IoT device may be configured / defined to transmit including a preamble during UL transmission.

[0314] 3) Whether or not an A-IoT device (e.g., a tag) transmits an UL (extended) preamble can be explicitly set / instructed by an A-IoT BS (e.g., a leader) via a message / command in the DL payload. That is, whether or not to transmit a UL preamble or a UL extended preamble can be set / instructed via a command from the A-IoT BS.

[0315] 4) The length of the UL extended preamble can be set to multiple values. This method can be applied additionally to the proposed methods described above.

[0316] For example, if the pilot tone portion constituting the UL extended preamble was N data_0 symbols, it can be extended to N, 2N, 3N, 4N data_0 symbols, etc. (for example, N=12). In this case, the UL extended preamble #1 can be defined as a {N * data_0 symbol + preamble} structure, the UL extended preamble #2 can be defined as a {2N * data_0 symbol + preamble} structure, and the UL extended preamble #3 can be defined as a {3N * data_0 symbol + preamble} structure.

[0317] Alternatively, a violation can be defined when defining a preamble so that it can be distinguished from the UL encoded data symbols. The violation can be defined to have multiple different patterns, and different extended preambles can be defined to use one or more different patterns. For example, assume that a 1010V1 pattern (#1) and a 10V101 pattern (#2) are defined. Extended preamble #1 can be defined with the structure {N * data_0 symbols + preamble with pattern #1}, extended preamble #2 can be defined with the structure {N * data_0 symbols + preamble with pattern #2 + preamble with pattern #1}, and extended preamble #3 can be defined with the structure {N * data_0 symbols + preamble with pattern #2 + preamble with pattern #2 + preamble with pattern #1}. As described above, when extended preambles having different lengths are defined / set, extended preambles #1 / #2 / #3, etc. can be set / applied differently depending on the range of the interval between the DL command and the UL response.

[0318] FIG. 11 illustrates the operation of a device for obtaining synchronization according to one embodiment of the present disclosure.

[0319] FIG. 11 illustrates the operation of a device (i.e., a base station or an intermediate node, e.g., a leader) based on the proposed methods in the embodiments described above. The example in FIG. 11 is provided for convenience of explanation and does not limit the scope of the present disclosure. Some of the step(s) illustrated in FIG. 11 may be omitted depending on the situation and / or setting. In addition, the device in FIG. 11 is only an example and may be implemented as the device illustrated in FIG. 13 below. For example, the processor (102 / 202) in FIG. 13 may control the transceiver (106 / 206) to transmit and receive channels / signals / data / information, etc., and may also control the processor (102 / 202) in FIG. 13 to store the channels / signals / data / information, etc. to be transmitted or received, in the memory (104 / 204).

[0320] Additionally, the operation of FIG. 11 may be processed by one or more processors (102, 202) of FIG. 13. Additionally, the operation of FIG. 11 may be stored in a memory (e.g., one or more memories (104, 204) of FIG. 13) in the form of a command / program (e.g., an instruction, an executable code) for driving at least one processor (e.g., 102, 202) of FIG. 13.

[0321] In FIG. 11, a signal transmitted for obtaining timing / synchronization proposed in the present disclosure (e.g., DL / UL preamble, frame-synchronization signal, etc.) is referred to as a first signal.

[0322] In FIG. 11, a device (e.g., a leader, a base station, an intermediate node) that transmits a first signal proposed in the present disclosure is referred to as a first device, and a device (e.g., a tag, an A-IoT device) that receives the first signal is referred to as a second device. For example, the first device may be a device that transmits a carrier wave for energy harvesting or backscattering, and the second device may be a device that responds with a backscattered signal based on the carrier wave.

[0323] Referring to FIG. 11, the first device transmits a first signal for timing acquisition to the second device (S1101).

[0324] Here, the first signal may include an ON / OFF pattern (e.g., Tari_F / P in the above-described embodiment) so that the first signal can be distinguished from the first channel, and information for determining a time unit (i.e., symbol length or chip duration) for transmitting data in the first channel and / or the second channel. For example, based on the data being encoded in an OOK (on-off-keying) format, the time unit for transmitting the data may be a symbol length (e.g., chip duration) for transmitting one bit.

[0325] In addition, the on / off pattern may be defined as twice the symbol length for transmitting the one bit. Here, the on / off pattern may be defined to be distinguished from the on / off form of two consecutive bits. For example, when data_0 and / or data_1 to be used in DL are encoded in the form of OOK (on-off keying), the symbol power level or pulse of data_0 may be composed of 1 symbol having the form of 'off-on', and the symbol power level or pulse of data 1 may be composed of 1 symbol having the form of 'on-off'. Here, the symbol power level or pulse of the first part can be set / defined to be distinguished from the form in which on-off and / or off-on are repeated (i.e., on-off-on-off and / or off-on-off-on), such as {off-on-on-on} or {off-off-on-on} or {on-on-off-on} or {on-on-off-on}.

[0326] Additionally, the first signal may further include at least one of a coding rate for the first channel and / or the second channel, a length of transmission time for the first channel, and delay information for the second channel.

[0327] Additionally, a delimiter may be transmitted prior to transmission of the first signal to identify the transmission of the first signal.

[0328] The first device transmits the first channel to the second device (S1102).

[0329] Here, the first channel may be a physical reader-to-device channel (PRDCH).

[0330] Additionally, the first channel may be transmitted after the first signal (e.g., consecutively in the time domain).

[0331] Additionally, based on the first channel being transmitted after the first signal, one or more dummy bits may be attached to the first signal, and the first channel may follow the one or more dummy bits.

[0332] Additionally, the first channel includes a midamble for timing synchronization, and information related to transmission of the first channel and / or the second channel provided by the synchronization signal can be changed by the midamble.

[0333] For example, the midamble may provide changed information regarding the information related to transmission of the first channel and / or the second channel provided by the synchronization signal. Alternatively, the midamble may indicate a subset or difference value regarding the information related to transmission of the first channel and / or the second channel provided by the synchronization signal.

[0334] The first device receives a second channel in response to the first channel from the second device (S1103).

[0335] Here, the second channel may be a physical device-to-reader channel (PDRCH).

[0336] FIG. 12 illustrates the operation of a device for obtaining synchronization according to one embodiment of the present disclosure.

[0337] FIG. 12 illustrates the operation of a device (i.e., an A-IoT device, e.g., a tag) based on the proposed methods in the embodiments described above. The example in FIG. 12 is provided for convenience of explanation and does not limit the scope of the present disclosure. Some step(s) illustrated in FIG. 12 may be omitted depending on circumstances and / or settings. In addition, the device in FIG. 12 is only an example and may be implemented as the device illustrated in FIG. 13 below. For example, the processor (102 / 202) in FIG. 13 may control the transceiver (106 / 206) to transmit and receive channels / signals / data / information, etc., and may also control the processor (102 / 202) in FIG. 13 to store transmitted or received channels / signals / data / information, etc. in the memory (104 / 204).

[0338] Additionally, the operation of FIG. 12 may be processed by one or more processors (102, 202) of FIG. 13. Additionally, the operation of FIG. 12 may be stored in a memory (e.g., one or more memories (104, 204) of FIG. 13) in the form of a command / program (e.g., an instruction, an executable code) for driving at least one processor (e.g., 102, 202) of FIG. 13.

[0339] In FIG. 12, a signal transmitted for obtaining timing / synchronization proposed in the present disclosure (e.g., DL / UL preamble, frame-synchronization signal, etc.) is referred to as a first signal.

[0340] In FIG. 12, a device (e.g., a leader, a base station, an intermediate node) that transmits a first signal proposed in the present disclosure is referred to as a first device, and a device (e.g., a tag) that receives the first signal is referred to as a second device. For example, the first device may be a device that transmits a carrier wave for energy harvesting or backscattering, and the second device may be a device that responds with a backscattered signal based on the carrier wave.

[0341] Referring to FIG. 12, the second device receives a first signal for timing acquisition from the first device (S1201).

[0342] Here, the first signal may include an ON / OFF pattern (e.g., Tari_F / P in the above-described embodiment) so that the first signal can be distinguished from the first channel, and information for determining a time unit (i.e., symbol length or chip duration) for transmitting data in the first channel and / or the second channel. For example, based on the data being encoded in an OOK (on-off-keying) format, the time unit for transmitting the data may be a symbol length (e.g., chip duration) for transmitting one bit.

[0343] In addition, the on / off pattern may be defined as twice the symbol length for transmitting the one bit. Here, the on / off pattern may be defined to be distinguished from the on / off form of two consecutive bits. For example, when data_0 and / or data_1 to be used in DL are encoded in the form of OOK (on-off keying), the symbol power level or pulse of data_0 may be composed of 1 symbol having the form of 'off-on', and the symbol power level or pulse of data 1 may be composed of 1 symbol having the form of 'on-off'. Here, the symbol power level or pulse of the first part can be set / defined to be distinguished from the form in which on-off and / or off-on are repeated (i.e., on-off-on-off and / or off-on-off-on), such as {off-on-on-on} or {off-off-on-on} or {on-on-off-on} or {on-on-off-on}.

[0344] Additionally, the first signal may further include at least one of a coding rate for the first channel and / or the second channel, a length of transmission time for the first channel, and delay information for the second channel.

[0345] Additionally, a delimiter may be transmitted prior to transmission of the first signal to identify the transmission of the first signal.

[0346] The second device receives the first channel from the first device (S1202).

[0347] Here, the first channel may be a physical reader-to-device channel (PRDCH).

[0348] Additionally, the first channel may be transmitted after the first signal (e.g., consecutively in the time domain).

[0349] Additionally, based on the first channel being transmitted after the first signal, one or more dummy bits may be attached to the first signal, and the first channel may follow the one or more dummy bits.

[0350] Additionally, the first channel includes a midamble for timing synchronization, and information related to transmission of the first channel and / or the second channel provided by the synchronization signal can be changed by the midamble.

[0351] For example, the midamble may provide changed information regarding the information related to transmission of the first channel and / or the second channel provided by the synchronization signal. Alternatively, the midamble may indicate a subset or difference value regarding the information related to transmission of the first channel and / or the second channel provided by the synchronization signal.

[0352] The second device transmits the second channel to the first device in response to the first channel (S1203).

[0353] Here, the second channel may be a physical device-to-reader channel (PDRCH).

[0354] General devices to which the present disclosure may be applied

[0355] FIG. 13 illustrates a block diagram of a wireless communication device according to one embodiment of the present disclosure.

[0356] Referring to FIG. 13, 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).

[0357] A first wireless device (100) includes one or more processors (102) and one or more memories (104), and may further include one or more transceivers (106) and / or one or more antennas (108). The processor (102) controls the memories (104) and / or the transceivers (106), and may be configured to implement the descriptions, functions, procedures, proposals, methods, and / or operational flowcharts disclosed in the present disclosure. For example, the processor (102) may process information in the memory (104) to generate first information / signal, and then transmit a wireless signal including the first information / signal via the transceiver (106). In addition, the processor (102) may receive a wireless signal including second information / signal via the transceiver (106), and then store information obtained from 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 perform some or all of the processes controlled by the processor (102), or may store software code including commands for performing the descriptions, functions, procedures, proposals, methods, and / or operation flowcharts disclosed in the present disclosure. Here, the processor (102) and the memory (104) may be part of a communication modem / circuit / chip designed to implement a 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 via one or more antennas (108). The transceiver (106) may include a transmitter and / or a receiver. The transceiver (106) may be used interchangeably with an RF (Radio Frequency) unit. In the present disclosure, a wireless device may also mean a communication modem / circuit / chip.

[0358] A second wireless device (200) includes one or more processors (202), one or more memories (204), and may further include one or more transceivers (206) and / or one or more antennas (208). The processor (202) controls the memories (204) and / or the transceivers (206), and may be configured to implement the descriptions, functions, procedures, proposals, methods, and / or operational flowcharts disclosed in the present disclosure. For example, the processor (202) may process information in the memory (204) to generate third information / signals, and then transmit a wireless signal including the third information / signals via the transceivers (206). Furthermore, the processor (202) may receive a wireless signal including fourth information / signals via the transceivers (206), and then store information obtained from signal processing of the fourth information / signals in the memory (204). The memory (204) may be connected to the processor (202) and may store various information related to the operation of the processor (202). For example, the memory (204) may perform some or all of the processes controlled by the processor (202), or may store software code including commands for performing the descriptions, functions, procedures, proposals, methods, and / or operational flowcharts disclosed in the present disclosure. Here, the processor (202) and the memory (204) may be part of a communication modem / circuit / chip designed to implement a wireless communication technology (e.g., LTE, NR). The transceiver (206) may be connected to the processor (202) and may transmit and / or receive wireless signals via one or more antennas (208). The transceiver (206) may include a transmitter and / or a receiver. The transceiver (206) may be used interchangeably with an RF unit. In the present disclosure, a wireless device may also mean a communication modem / circuit / chip.

[0359] 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 one or more Service Data Units (SDUs) according to the descriptions, functions, procedures, proposals, methods, and / or operational flowcharts disclosed in the present disclosure. One or more processors (102, 202) may generate messages, control information, data, or information according to the descriptions, functions, procedures, proposals, methods, and / or operational flowcharts disclosed in the present disclosure. One or more processors (102, 202) can generate signals (e.g., baseband signals) including PDUs, SDUs, messages, control information, data or information according to the functions, procedures, proposals and / or methods disclosed in the present disclosure, and provide the signals to one or more transceivers (106, 206). One or more processors (102, 202) can receive signals (e.g., baseband signals) from one or more transceivers (106, 206) and obtain PDUs, SDUs, messages, control information, data or information according to the descriptions, functions, procedures, proposals, methods and / or operational flowcharts disclosed in the present disclosure.

[0360] One or more processors (102, 202) may be referred to as a controller, a microcontroller, a microprocessor, or a 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). The descriptions, functions, procedures, proposals, methods, and / or operational flowcharts disclosed in this disclosure may be implemented using firmware or software, and the firmware or software may be implemented to include modules, procedures, functions, etc. The descriptions, functions, procedures, proposals, methods and / or operation flowcharts disclosed in this disclosure may be implemented using firmware or software configured to perform 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 flowcharts disclosed in this disclosure may be implemented using firmware or software in the form of codes, instructions and / or sets of instructions.

[0361] One or more memories (104, 204) may be coupled to one or more processors (102, 202) and may store various forms of data, signals, messages, information, programs, codes, instructions, and / or commands. The one or more memories (104, 204) may be configured as ROM, RAM, EPROM, flash memory, hard drives, registers, cache memory, computer-readable storage media, and / or combinations thereof. The one or more memories (104, 204) may be located internally and / or externally to the one or more processors (102, 202). Additionally, the one or more memories (104, 204) may be coupled to the one or more processors (102, 202) via various technologies, such as wired or wireless connections.

[0362] One or more transceivers (106, 206) can transmit user data, control information, wireless signals / channels, etc., as mentioned in the methods and / or flowcharts of the present disclosure, to one or more other devices. One or more transceivers (106, 206) can receive user data, control information, wireless signals / channels, etc., as mentioned in the descriptions, functions, procedures, proposals, methods and / or flowcharts of the present disclosure, from one or more other devices. For example, one or more transceivers (106, 206) can be connected to one or more processors (102, 202) and can transmit and receive wireless signals. For example, one or more processors (102, 202) can 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 coupled 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, or the like, as referred to in the descriptions, functions, procedures, proposals, methods, and / or operational flowcharts disclosed in the present disclosure, via one or more antennas (108, 208). In the present disclosure, 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 received user data, control information, wireless signals / channels, etc. from RF band signals to baseband signals in order to process the received user data, control information, wireless signals / channels, etc. using one or more processors (102, 202).One or more transceivers (106, 206) may convert user data, control information, wireless signals / channels, etc. processed by one or more processors (102, 202) from baseband signals to RF band signals. For this purpose, one or more transceivers (106, 206) may include an (analog) oscillator and / or filter.

[0363] The embodiments described above are combinations of components and features of the present disclosure in a predetermined form. Each component or feature should be considered optional unless explicitly stated otherwise. Each component or feature may be implemented without being combined with other components or features. Furthermore, it is also possible to form embodiments of the present disclosure by combining some components and / or features. The order of operations described in the embodiments of the present disclosure may be changed. Some components or features of one embodiment may be included in another embodiment or may be replaced with corresponding components or features of another embodiment. It is self-evident that claims that do not have an explicit citation relationship in the patent claims may be combined to form embodiments or incorporated as new claims through post-application amendments.

[0364] It will be apparent to those skilled in the art that the present disclosure may be embodied in other specific forms without departing from the essential characteristics thereof. Therefore, the above detailed description should not be construed as limiting in any respect, but rather as illustrative. The scope of the present disclosure should be determined by a reasonable interpretation of the appended claims, and all modifications within the scope of equivalents of the present disclosure are intended to be included within the scope of the present disclosure.

[0365] The scope of the present disclosure includes software or machine-executable instructions (e.g., an operating system, an application, firmware, a program, etc.) that cause operations according to the methods of various embodiments to be executed on a device or a computer, and a non-transitory computer-readable medium having such software or instructions stored thereon and executable on the device or computer. Instructions that can be used to program a processing system to perform the features described in the present disclosure can be stored on / in a storage medium or a computer-readable storage medium, and a computer program product including such a storage medium can be used to implement the features described in the present disclosure. The storage medium can include, but is not limited to, high-speed random access memory, such as DRAM, SRAM, DDR RAM, or other random access solid state memory devices, and can include non-volatile memory, such as one or more magnetic disk storage devices, optical disk storage devices, flash memory devices, or other non-volatile solid state storage devices. The memory optionally includes one or more storage devices remotely located from the processor(s). The memory or, alternatively, the non-volatile memory device(s) within the memory comprise a non-transitory computer-readable storage medium. The features described in this disclosure may be incorporated into software and / or firmware stored on any of the machine-readable media, which may control the hardware of the processing system and allow the processing system to interact with other mechanisms that utilize results according to embodiments of the present disclosure. Such software or firmware may include, but is not limited to, application code, device drivers, operating systems, and execution environments / containers.

[0366] Here, the wireless communication technology implemented in the wireless device (100, 200) of the present disclosure may include not only LTE, NR, and 6G, but also Narrowband Internet of Things for low-power communication. At this time, for example, NB-IoT technology may be an example of LPWAN (Low Power Wide Area Network) technology, and may be implemented with standards such as LTE Cat NB1 and / or LTE Cat NB2, and is not limited to the above-described names. Additionally or alternatively, the wireless communication technology implemented in the wireless device (XXX, YYY) of the present disclosure may perform communication based on LTE-M technology. At this time, for example, LTE-M technology may be an example of LPWAN technology, and may be called by various names such as eMTC (enhanced Machine Type Communication). For example, LTE-M technology can be implemented by at least one of various standards such as 1) LTE CAT 0, 2) LTE Cat M1, 3) LTE Cat M2, 4) LTE non-BL (non-Bandwidth Limited), 5) LTE-MTC, 6) LTE Machine Type Communication, and / or 7) LTE M, and is not limited to the above-described names. Additionally or alternatively, the wireless communication technology implemented in the wireless device (XXX, YYY) of the present disclosure can include at least one of ZigBee, Bluetooth, and Low Power Wide Area Network (LPWAN) considering low-power communication, and is not limited to the above-described names. For example, ZigBee technology can create personal area networks (PAN) related to small / low-power digital communication based on various standards such as IEEE 802.15.4, and can be called by various names.

[0367] The method proposed in this disclosure is explained with a focus on examples applied to 3GPP LTE / LTE-A and 5G systems, but can be applied to various wireless communication systems in addition to 3GPP LTE / LTE-A and 5G systems.

Claims

1. A step of transmitting a first signal for timing acquisition to a second device by a first device; A step of transmitting a first channel to the second device by the first device; and A step of receiving a second channel in response to the first channel from the second device by the first device, A method wherein the first signal comprises an ON / OFF pattern so that the first signal can be distinguished from the first channel and information for determining a time unit for transmission of data in the first channel and / or the second channel.

2. In paragraph 1, A method in which the time unit for transmitting the data is a symbol length for transmitting one bit, based on the fact that the above data is encoded in an OOK (on-off-keying) format.

3. In paragraph 2, A method wherein the above on / off pattern is defined as twice the symbol length for transmitting the above one bit.

4. In paragraph 3, A method in which the above on / off pattern is defined to be distinguished from the on / off form of two consecutive bits.

5. In paragraph 1, A method wherein one or more dummy bits are attached to the first signal based on the first channel being transmitted after the first signal, and the first channel follows the one or more dummy bits.

6. In paragraph 1, A method wherein the first signal further includes at least one of a coding rate for the first channel and / or the second channel, a length of a transmission time for the first channel, and delay information for the second channel.

7. In paragraph 6, The first channel includes a midamble for timing synchronization, A method in which information related to transmission of the first channel and / or the second channel provided by the synchronization signal is changed by the midamble.

8. In paragraph 7, A method wherein the midamble re-indicates changed information with respect to information related to transmission of the first channel and / or the second channel provided by the synchronization signal.

9. In paragraph 7, A method wherein the midamble indicates a subset or difference value for information related to transmission of the first channel and / or the second channel provided by the synchronization signal.

10. In paragraph 1, A method in which a delimiter for identifying transmission of the first signal is transmitted prior to transmission of the first signal.

11. In paragraph 1, The first device is a device that transmits a carrier wave for energy harvesting or backscattering, A method wherein the second device is a device that responds with a backscattered signal based on the carrier wave.

12. In paragraph 1, A method wherein the first channel is a physical reader-to-device channel (PRDCH) and the second channel is a physical device-to-reader channel (PDRCH).

13. The first device is: One or more transceivers for transmitting and receiving wireless signals; and comprising one or more processors controlling one or more of the above transceivers, One or more of the above processors: Transmit a first signal for timing acquisition to a second device; Transmitting the first channel to the second device; and is set to receive a second channel in response to the first channel from the second device; A first device, wherein the first signal includes an ON / OFF pattern so that the first signal can be distinguished from the first channel and information for determining a time unit for transmission of data in the first channel and / or the second channel.

14. One or more non-transitory computer-readable media storing one or more instructions, The one or more instructions are executed by one or more processors, so that the first device: Transmit a first signal for timing acquisition to a second device; Transmitting the first channel to the second device; and Control to receive a second channel in response to the first channel from the second device, A computer-readable medium, wherein the first signal comprises an ON / OFF pattern and information for determining a time unit for transmission of data in the first channel and / or the second channel so that the first signal can be distinguished from the first channel.

15. In a processing device set to control a first device, the processing device: one or more processors; and One or more computer memories operatively connected to said one or more processors and storing instructions for performing operations based on execution by said one or more processors, The above actions are: A step of transmitting a first signal for timing acquisition to a second device; a step of transmitting a first channel to the second device; and comprising the step of receiving a second channel in response to the first channel from the second device; A processing device wherein the first signal includes an ON / OFF pattern so that the first signal can be distinguished from the first channel and information for determining a time unit for transmission of data in the first channel and / or the second channel.

16. A step of receiving a first signal for timing acquisition from a first device by a second device; A step of receiving a first channel from the first device by the second device; and A step of transmitting a second channel to the first device in response to the first channel by the second device, A method wherein the first signal comprises an ON / OFF pattern so that the first signal can be distinguished from the first channel and information for determining a time unit for transmission of data in the first channel and / or the second channel.

17. The second device is: One or more transceivers for transmitting and receiving wireless signals; and comprising one or more processors controlling one or more of the above transceivers, One or more of the above processors: Receive a first signal for timing acquisition from a first device; Receive a first channel from the first device; and is configured to transmit a second channel to the first device in response to the first channel; A second device, wherein the first signal includes an ON / OFF pattern so that the first signal can be distinguished from the first channel and information for determining a time unit for transmission of data in the first channel and / or the second channel.

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