Method and device for collision control in wireless communication system

Abstract

Disclosed are a method and a device for collision control in a wireless communication system. The method according to an embodiment of the present disclosure may comprise the steps of: receiving, by a first device, a first transmission from a second device, the first transmission including first information for determining a slot number counter; transmitting, by the first device, a second transmission to the second device on the basis of the slot number counter; and retransmitting, by the first device, the second transmission on the basis of collision of the second transmission.

Description

Method and device for collision control in wireless communication systems

[0001] The present disclosure relates to a wireless communication system, and more particularly, to a method and device for collision control 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 controlling collision in a wireless communication system supporting the ambient internet of things (A-IoT).

[0005] 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 will be clearly understood by a person having ordinary skill in the technical field to which the present disclosure belongs from the description below.

[0006] A method according to an aspect of the present disclosure may include: receiving, by a first device, a first transmission from a second device, the first transmission including first information for determining a slot number counter; transmitting, by the first device, a second transmission to the second device based on the slot number counter; and retransmitting, by the first device, the second transmission based on a collision of the second transmission. The second transmission may be retransmitted based on an additional counter or backoff timer determined due to the collision of the second transmission.

[0007] A method according to an additional aspect of the present disclosure may include: transmitting, by a second device, a first transmission to a first device, the first transmission including first information for determining a slot number counter; and receiving, by the second device, a second transmission from the first device. The second transmission may be transmitted based on the slot number counter, and the second transmission may be retransmitted based on an additional counter or backoff timer determined due to a collision of the second transmission.

[0008] According to an embodiment of the present disclosure, the probability of collision between devices in a wireless communication system supporting A-IoT can be reduced.

[0009] In addition, according to an embodiment of the present disclosure, it is possible to prevent a problem in which a device cannot complete a contention-based access procedure due to insufficient energy in a wireless communication system supporting A-IoT.

[0010] 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.

[0011] 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.

[0012] Figure 1 illustrates the structure of a wireless communication system to which the present disclosure can be applied.

[0013] FIG. 2 illustrates a frame structure in a wireless communication system to which the present disclosure can be applied.

[0014] FIG. 3 illustrates a resource grid in a wireless communication system to which the present disclosure can be applied.

[0015] FIG. 4 illustrates a physical resource block in a wireless communication system to which the present disclosure can be applied.

[0016] FIG. 5 illustrates a slot structure in a wireless communication system to which the present disclosure can be applied.

[0017] 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.

[0018] FIG. 7 illustrates an ambient IoT device architecture in a wireless communication system to which the present disclosure can be applied.

[0019] 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.

[0020] FIG. 9 illustrates a logical system architecture in a wireless communication system to which the present disclosure can be applied.

[0021] FIG. 10 is a diagram illustrating A-IoT operation in a wireless communication system to which the present disclosure can be applied.

[0022] FIG. 11 illustrates the operation of a device for collision control according to one embodiment of the present disclosure.

[0023] FIG. 12 illustrates the operation of a device for collision control according to one embodiment of the present disclosure.

[0024] FIG. 13 illustrates a block diagram of a wireless communication device according to one embodiment of the present disclosure.

[0025] 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.

[0026] 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.

[0027] 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.

[0028] 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.

[0029] 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.

[0030] 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.

[0031] 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.

[0032] 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.

[0033] 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.

[0034] For clarity, the description is based on the 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.

[0035] 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).

[0036] 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).

[0037] Abbreviations for terms that may be used in this disclosure are defined as follows.

[0038] - BM: beam management

[0039] - CQI: Channel Quality Indicator

[0040] - CRI: Channel state information - reference signal resource indicator

[0041] - CSI: Channel State Information

[0042] - CSI-IM: Channel State Information - Interference Measurement

[0043] - CSI-RS: Channel state information - reference signal

[0044] - DMRS: Demodulation Reference Signal

[0045] - FDM: frequency division multiplexing

[0046] - FFT: fast Fourier transform

[0047] - IFDMA: interleaved frequency division multiple access

[0048] - IFFT: inverse fast Fourier transform

[0049] - L1-RSRP: Layer 1 reference signal received power

[0050] - L1-RSRQ: Layer 1 reference signal received quality

[0051] - MAC: Medium Access Control

[0052] - NZP: non-zero power

[0053] - OFDM: orthogonal frequency division multiplexing

[0054] - PDCCH: Physical downlink control channel

[0055] - PDSCH: Physical downlink shared channel

[0056] - PMI: precoding matrix indicator

[0057] - RE: resource element

[0058] - RI: Rank indicator

[0059] - RRC: Radio Resource Control

[0060] - RSSI: Received signal strength indicator

[0061] - Rx: Reception

[0062] - QCL: quasi co-location

[0063] - SINR: signal to interference and noise ratio

[0064] - SSB (or SS / PBCH block): Synchronization signal block (including primary synchronization signal (PSS), secondary synchronization signal (SSS), and physical broadcast channel (PBCH))

[0065] - TDM: Time Division Multiplexing

[0066] - TRP: transmission and reception point

[0067] - TRS: Tracking Reference Signal

[0068] - Tx: transmission

[0069] - UE: user equipment

[0070] - ZP: Zero Power

[0071] System General

[0072] 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.

[0073] 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.

[0074] 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.

[0075] Figure 1 illustrates the structure of a wireless communication system to which the present disclosure can be applied.

[0076] 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.

[0077] FIG. 2 illustrates a frame structure in a wireless communication system to which the present disclosure can be applied.

[0078] 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.

[0079] 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.

[0080] μΔf=2 μ ·15 [kHz]CP015 Normal 130 Normal 260 Normal, Extended 3120 Normal 4240 Normal

[0081] 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.

[0082] 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).

[0083] Frequency Range Designation Corresponding Frequency Range Subcarrier Spacing FR1410MHz - 7125MHz 15, 30, 60kHz FR224250MHz - 52600MHz 60, 120, 240kHz

[0084] 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.

[0085] 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.

[0086] μN symb slot N slot frame,μ N slotsubframe,μ01410111420221440431480841416016

[0087] μN symb slot N slot frame,μ N slot subframe,μ212404

[0088] 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.

[0089] 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.

[0090] 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.

[0091] FIG. 3 illustrates a resource grid in a wireless communication system to which the present disclosure can be applied.

[0092] 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 each antenna port p. Each element of the resource grid for μ and each antenna port p is referred to as a resource element and is uniquely identified by an index pair (k, l'). Here, 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.

[0093] Point A serves as a common reference point of the resource block grid and is obtained as follows.

[0094] - 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.

[0095] - absoluteFrequencyPointA represents the frequency-position of point A expressed as ARFCN (absolute radio-frequency channel number).

[0096] 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.

[0097]

[0098] 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.

[0099]

[0100] N BWP,i start,μ is a common resource block where BWP starts relative to common resource block 0.

[0101] 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.

[0102] 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.

[0103] 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.

[0104] 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).

[0105] 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.

[0106] 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.

[0107] 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.

[0108] 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.

[0109] 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 carried on the PDCCH (S602).

[0110] 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.

[0111] 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.

[0112] 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.

[0113] Table 5 shows an example of the DCI format in the NR system.

[0114] 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

[0115] 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.

[0116] 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).

[0117] 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.

[0118] 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.

[0119] 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.

[0120] 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.

[0121] 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.

[0122] 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.

[0123] Ambient Internet of Things (A-IoT)

[0124] 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.

[0125] 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.

[0126] 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.

[0127] 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).

[0128] FIG. 7 illustrates an ambient IoT device architecture in a wireless communication system to which the present disclosure can be applied.

[0129] - Antenna: The antenna may be shared or separate for the radio frequency (RF) energy harvester and receiver / transmitter.

[0130] - Matching network: The matching network matches the impedance between the antenna and other components (including RF energy harvester and receiver-related blocks).

[0131] - 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).

[0132] - Energy storage (e.g., capacitor): Stores energy harvested from the RF energy harvester.

[0133] - 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.

[0134] - (Digital) BB (balanced-balanced) logic: BB logic includes functional blocks such as encoder, decoder, and controller.

[0135] - 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.

[0136] - 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.

[0137] The receiving related blocks include:

[0138] - RF band pass filter (BPF) to improve selectivity: RF BPF may not exist depending on the implementation.

[0139] - RF envelope detector: The RF envelope detector converts the RF signal to baseband.

[0140] - 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.

[0141] - Comparator: The comparator determines whether the input signal is high or low.

[0142] The receiving related blocks include:

[0143] - Backscatter modulator: The backscatter modulator modulates the backscatter signal into a signal transmitted from the BB logic by switching the impedance.

[0144] 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).

[0145] 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.

[0146] 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.

[0147] - Transmission modulator: The transmission modulator modulates baseband bits according to a modulation method.

[0148] - Digital-to-analog converter (DAC): A DAC converts a digital signal into an analog signal.

[0149] - Low pass filter (LPF): LPF filters out unwanted signals.

[0150] - Mixer: The mixer upconverts the baseband signal to the RF range.

[0151] - Local oscillator (LO): LO generates the carrier frequency.

[0152] - Frequency locked loop (FLL) / phase-locked loop (PLL): Can be used for frequency synthesis, but may not be present depending on the implementation.

[0153] - Power amplifier (PA): The PA amplifies the transmission signal.

[0154] Below, we describe solutions for ambient IoT.

[0155] A-IoT processing time can be defined by the following timing relationship:

[0156] TR2D_min: Minimum time between an R2D transmission and the corresponding D2R transmission.

[0157] TD2R_min: Minimum time between a D2R transmission and its corresponding R2D transmission.

[0158] TD2R_max: Maximum time between a D2R transmission and its corresponding R2D transmission.

[0159] TR2D_R2D_min: Minimum time between two different consecutive R2D transmissions to the same A-IoT device.

[0160] TD2R_D2R_min: Minimum time between two different consecutive D2R transmissions from the same A-IoT device.

[0161] 1. R2D (reader-to-device)

[0162] 1) R2D waveform, modulation, and numerology

[0163] 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.

[0164] 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.

[0165] 2) PRDCH (physical reader-to-device channel)

[0166] 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.

[0167] 3) R2D timing

[0168] 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.

[0169] 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.

[0170] 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.

[0171] 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.

[0172] 4) R2D scheduling

[0173] 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)).

[0174] 2. D2R (device-to-reader)

[0175] 1) Waveform and modulation

[0176] 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.

[0177] 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.

[0178] The following D2R baseband modulations are discussed for all devices:

[0179] - OOK

[0180] - BPSK (binary phase shift keying)

[0181] - BFSK (binary frequency shift keying), MSK (minimum shift keying)

[0182] 2) PDRCH (physical device-to-reader channel)

[0183] 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).

[0184] 3) D2R timing

[0185] 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.

[0186] 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.

[0187] 4) D2R scheduling

[0188] For D2R scheduling, the following information can be explicitly / implicitly indicated to the device via the PRDCH:

[0189] - Time domain resources

[0190] - Frequency domain resources

[0191] - MCS-like information

[0192] - Chip duration

[0193] - ID associated with the device(s)

[0194] - Repeat

[0195] - Information about midamble (if supported)

[0196] 3. Overall procedure

[0197] 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.

[0198] - 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.

[0199] Here, the A-IoT paging function can use A-IoT paging messages to indicate the device(s) that require a response.

[0200] 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.

[0201] 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.

[0202] - 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.

[0203] 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.

[0204] Slotted-ALOHA (slotted-additive links on-line Hawaii area) can be used as an A-IoT random access procedure.

[0205] 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).

[0206] 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.

[0207] - Step C1: Possible R2D data transmission (e.g. command transmission).

[0208] - Step C2: Possible D2R data transmission (e.g., response to a command).

[0209] 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).

[0210] 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.

[0211] 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.

[0212] 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.

[0213] 4. RAN Architecture

[0214] FIG. 9 illustrates a logical system architecture in a wireless communication system to which the present disclosure can be applied.

[0215] 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).

[0216] - A-IoT device: A device that supports ambient IoT.

[0217] - A-IoT RAN: Hosts specific functions for A-IoT as part of the RAN's functionality.

[0218] - 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.

[0219] - A-IoT CN: Hosts specific functions for A-IoT in terms of CN's functional aspects.

[0220] - XX Interface: Interface between A-IoT RAN / A-IoT supporting gNB and A-IoT CN where specific A-IoT specific functions are performed.

[0221] - Common reader function: Ability to communicate with A-IoT devices via A-IoT wireless.

[0222] - A-IoT RAN node functions: Functions including, for example, control of A-IoT radio resources used for A-IoT devices.

[0223] 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.

[0224] 5. Information exchanged between the A-IoT CN (core network) and the A-IoT RAN (radio access network).

[0225] Information about A-IoT service types (e.g., inventory, commands) can be directed to the leader from the CN.

[0226] 1) Inventory: This refers to the service that the network provides to discover and obtain identifiers of A-IoT devices.

[0227] A-IoT CN can transmit inventory for a single device, a group of devices, or all devices.

[0228] An inventory request transmitted from an A-IoT CN to an A-IoT RAN may include:

[0229] - A-IoT device identification (to find a single device, a group of devices, or all devices)

[0230] - The scope of the inventory request (e.g. the specific area where the inventory will be triggered)

[0231] Multiple individual A-IoT device IDs (one ID per device) can be provided to the A-IoT CN via a single inventory report.

[0232] 2) Command: This refers to the service (e.g., read, write, etc.) that the network provides to send work instructions to A-IoT devices.

[0233] A-IoT CN can transmit commands to a single device.

[0234] Collision Control Methods in Ambient IoT (A-IoT or AmIoT: ambient IoT) Systems

[0235] 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).

[0236] FIG. 10 is a diagram illustrating A-IoT operation in a wireless communication system to which the present disclosure can be applied.

[0237] 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.

[0238] 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.

[0239] 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.

[0240] 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.

[0241] Hereinafter, the present disclosure proposes a collision handling method between A-IoT devices that can be applied in an A-IoT system.

[0242] In this disclosure, ' / ' means 'and', 'or', or 'and / or' depending on the context.

[0243] Example 1: A method of introducing an additional counter when a collision conference method based on slot number counting is considered.

[0244] Assuming that a collision avoidance method based on slot number counting used in RFID (radio-frequency identification) is introduced to the A-IoT system, an additional counter separate from the slot number counter can be introduced. For example, an A-IoT BS (base station) (e.g., a reader) can set / instruct a Q value (Q is an integer greater than 0) (e.g., a value for generating a slot number) to an A-IoT device (e.g., a tag) through a DL payload and / or command, and can also set / instruct a value for generating an additional counter (e.g., a P value, where P is an integer greater than 0). Multiple tags can select / determine an arbitrary slot number based on the Q value and set it as the slot number counter. Multiple tags decrement the slot number counter value by 1. When the slot number counter value becomes 0, the tag transmits (i.e., responds) to the reader. If multiple tags transmit UL control information (e.g., random number or UE identifier (UE ID) information) at the same time with the slot number counter value based on the Q value being 0, a collision occurs.

[0245] Here, the collided tags decrease the additional counter value by 1 through an additional command from the reader (e.g., a command to decrease the additional counter by 1). Here, the tag can generate an additional counter value based on the P value. For example, the tag can select the additional counter value as an integer value from 1 to 2^P. For example, P can be indicated as one of 1 to K (K is an integer greater than 0). Afterwards, among the previously collided tags, a tag whose additional counter value becomes 0 can retransmit the previously collided UL control information.

[0246] Here, the additional commands directed by the leader can be selected / set / instructed for each channel / session, taking into account parallel inventory operations through multiple channels / sessions simultaneously.

[0247] Alternatively, a back-off timer may be used instead of the additional counter. Hereinafter, unless otherwise stated in the present disclosure, the slot number counter may be replaced with a back-off timer, or the description of the slot number counter may be equally applied to the operation of the back-off timer. For example, the tag may generate / determine the back-off timer value based on the P value. The tag attempts to transmit when the back-off timer value becomes 0 after waiting for the time of the back-off timer. That is, among the colliding tags, the tag whose back-off timer becomes 0 first may retransmit the UL control information without an additional command from the reader. Here, the reader may set / instruct the time interval (e.g., X ms) at which the tag decreases the back-off timer through a DL payload (e.g., a command, etc.).

[0248] Additionally, instead of the reader indicating a value (e.g., P) for generating an additional counter, the P value can be determined based on the slot number value selected by the tag. For example, if the tag is indicated by the reader as a Q value, the tag can select one of the integer values ​​from 1 to 2^Q. If the selected value is defined as q, the additional counter value can be defined to be selected as one of the values ​​from 1 to q.

[0249] Alternatively, the leader can be defined to additionally set / indicate an offset value, such that the additional counter value is selected as one of the values ​​between 1 and (q - offset).

[0250] If the tag's initially selected value based on its Q value is greater than or equal to a specific value set / instructed by the reader (e.g. 2^-Q-1), then no additional counter value may be set.

[0251] Additionally, whether to use the additional counter and / or additional back-off timer, etc., may be set / defined based on the (energy storage) capability of the tag, the priority of the tag, or the priority of the transmission to be transmitted by the tag.

[0252] For example, if the tag's (energy storage) capability is insufficient (or conversely, if there is room), the additional counter and / or additional back-off timer, etc. may be used. On the other hand, if the tag's (energy storage) capability is sufficient (or conversely, if there is room), the additional counter and / or additional back-off timer, etc. may not be used and may be set / defined to always return to the maximum value.

[0253] As another example, if the tag has a high priority, the additional counter and / or additional backoff timer may be used. On the other hand, if the tag has a low priority, the additional counter and / or additional backoff timer may not be used and may be set / defined to always return to the maximum value.

[0254] Additionally, in the above-described method, a counter value or backoff timer value may be predefined / set according to capability and / or priority. In this case, instead of returning to the maximum value, it may be set to return to a predefined / set value according to the tag's capability / priority, etc.

[0255] Alternatively, the interval at which the counters and / or timers are decremented may be adjusted (i.e., set differently) based on the tag's (energy storage) capability, the tag's priority, or the priority of the transmission the tag is to transmit.

[0256] Example 2: A method for adding post-collision tag actions when a collision conference method based on slot number counting is considered.

[0257] Assume that a collision avoidance method based on slot number counting used in RFID (radio-frequency identification) is introduced to the A-IoT system. As described above, the A-IoT BS (base station) (e.g., reader) sets / instructs an A-IoT device (e.g., tag) to set / instruct a Q value (Q is an integer greater than 0) (e.g., a value for generating a slot number) through a DL payload and / or a command. Multiple tags can determine / select an arbitrary slot number based on the Q value and set it as a slot number counter. Multiple tags decrease the slot number counter value by 1. When the slot number counter value becomes 0, the tag transmits (i.e., responds) to the reader.

[0258] If multiple tags collide by simultaneously transmitting UL control information (e.g., random number or UE-ID information) after the slot number counter value becomes 0 after a command from the leader, the colliding tags can select one of the following actions based on a probability of 1 / 2: (i) increasing the slot number counter value to the maximum and (2) retransmitting the UL control information immediately after (e.g., in the next slot).

[0259] Tags that collide during UL transmission can randomly re-determine / select a new slot number based on their Q value. This means that a different slot number value may be acquired than the previously acquired slot number value, which can reduce latency compared to the operation of always setting the slot number counter value to the maximum.

[0260] Alternatively, the colliding tags may randomly re-determine / select a new slot number based on a smaller value than the value previously considered when determining / selecting the slot number (e.g., Q value). For example, if a tag determined / selected a slot number by applying Q value before the collision of control information, after the collision, the tag may determine / select a slot number by applying half of the previously considered value (e.g., Q / 2) (e.g., one of 1 to 2^(Q / 2)).

[0261] Alternatively, the colliding tags may determine / select a slot number by considering a value (e.g., Q-offset) obtained by applying a specific offset value from the value previously considered when determining / selecting the slot number (e.g., Q value) (e.g., determined / selected as one of the values ​​from 1 to 2^(Q-offset)). Here, the offset value can be provided by the reader to the tag through a DL payload (e.g., a command), etc.

[0262] If a specific A-IoT device (e.g., a tag) transmits the first message (msg1) (e.g., a random number or UE-ID) with a slot number counter value of 0 and a collision occurs, the base station can increase the slot number counter value near the maximum value that can be selected through the Q value set / instructed (e.g., less than or equal to 2^-Q-1) (instead of incrementing the slot number counter to the maximum value that the device can count). This is to ensure that even tags that have collided once can get another chance to transmit in the corresponding inventory round. In addition, the reader can send more query (or query repeat) commands than 2^Q so that more tags can get a chance to transmit msg1 in the corresponding round.

[0263] Here, if multiple tags that collided at the same time change their slot number counter values ​​to 2-^Q-1, they will collide again the next time. To prevent this, the reader can pre-set / indicate the range of slot number values ​​that the colliding tags can select, or the starting point and number of slot numbers.

[0264] For example, the reader can set / instruct tags that failed to transmit msg1 (i.e., collided) to select a large number K (i.e., K slot numbers from 2^QK to 2^Q-K+1, 2^Q-K+2, ..., 2^Q-1) among the slot numbers that the reader can select through the Q value. The tags that failed to transmit msg1 can randomly select one of the K slot numbers and set it as a slot number counter. As another example, the reader can set / instruct tags that failed to transmit msg1 (i.e., collided) to select slot numbers X to Y (where X+Y-1 <= 2^Q-1). The tags that failed to transmit msg1 can randomly select one of the Y slot numbers and set it as a slot number counter.

[0265] Afterwards, if the leader sends an additional query (or query repeat) command, msg1 can be sent when the slot number counter becomes 0 for the tags that have newly selected / determined the slot number after the collision.

[0266] As another example, the initially selected slot number (counter) values ​​and the newly selected slot number (counter) values ​​can be mapped in advance. Specifically, when the reader sets / indicates the Q value, the tags can select one of the slot numbers from 0 to 2^Q-1. Here, the slot number values ​​initially selected by the tags that failed to transmit msg1 can be divided into two groups, from 0 to 2^(Q-1)-1 (i.e., the first group) and from 2^(Q-1) to 2^Q-1 (i.e., the second group), and M slot number values ​​that can be newly selected from each group can be set / indicated in advance. Here, the M can be selected in descending order from the largest value among the slot numbers that can be selected through the Q value. And, M slot numbers from slot numbers 2^Q-2M to 2^Q-2M+1, 2^Q-2M+2, ..., 2^QM-1 can be set to be mapped to the first group, and M slot numbers from slot numbers 2^QM to 2^Q-M+1, 2^Q-M+2, ..., 2^Q-1 can be set to be mapped to the second group.

[0267] Meanwhile, when the above-described methods are applied, it is necessary to determine in advance how many more retransmission opportunities (e.g., N times) a collided tag will be given. This information can be set / instructed to the tags by the reader when starting an inventory round (e.g., a process in which the reader confirms the presence of tags and collects data, and one round can mean one cycle), through a query command (i.e., a basic command requesting a response from tags in an inventory round) (or query adjustment (i.e., adjusting the response probability of tags by changing the slot size according to the number of tags after the query command), paging), etc. If the reader sets N=1 (i.e., the number of retransmissions), the tag that first collided at a certain point in time can re-select a slot number counter based on the above-described methods and re-enter the inventory round. However, at a certain point in time, the tag that collided for the second time will no longer reselect the slot number (or, defined as the maximum number (or infinite, etc.) that the tag can count) and can wait for the next inventory round. Here, depending on the value of N set by the leader, the leader can decrease the slot number to N*2^Q through query repetition, etc., so that all tags waiting for the next turn after the collision can attempt to transmit msg1.

[0268] In addition, tags that have collided once (or N times, whichever number the leader allows) can be given preferential treatment (e.g., priority) in subsequent inventory rounds. For example, even if the leader has set / instructed tags to use a Q value through a query command (or query adjustment command) for an inventory round, tags that failed to transmit msg1 in the previous inventory round can select a slot number by assuming a Q' value smaller than the Q value. Here, the benefit can be defined to increase based on the tag's cumulative number of collisions (or cumulative number of inventory round failures), etc. That is, assuming that the parameter 'a' is multiplied by the Q value to assume a smaller Q' value, the 'a' value can be set smaller as the tag's cumulative number of collisions (or cumulative number of inventory round failures) increases. Alternatively, assuming that the parameter 'b' is subtracted from the Q value to assume a smaller Q' value, the 'b' value can be set larger as the tag's cumulative number of collisions (or cumulative number of inventory round failures) increases. Here, the a value or b value can be individually set / instructed by the reader according to the cumulative number of collisions (or cumulative number of inventory round failures) of the tag. Alternatively, a formula for calculating the a value or b value according to the cumulative number of collisions (or cumulative number of inventory round failures) of the tag can be defined in advance so that the tag can determine the a value or b value.

[0269] The above-described proposed methods can be set / indicated for each tag / device type and / or each service type. For example, the application of the above-described proposed methods can be set / indicated for each tag / device type and / or each service type. Furthermore, among the above-described proposed methods, different (individual) proposed methods can be set / indicated for each tag / device type and / or each service type.

[0270] Example 3: A method that considers tag capabilities / priorities when considering a collision conference method based on slot number counting.

[0271] It can be assumed that a collision avoidance method based on slot number counting used in RFID (radio-frequency identification) is introduced to the A-IoT system. As described above, the A-IoT BS (base station) (e.g., reader) sets / instructs an A-IoT device (e.g., tag) to set / instruct a Q value (Q is an integer greater than 0) (e.g., a value for generating a slot number) through a DL payload and / or command. Multiple tags can determine / select an arbitrary slot number based on the Q value and set it as a slot number counter. Here, the Q value provided by the reader can be set to be applied differently depending on the capability and / or priority of the tag.

[0272] For example, it can be applied to set the Q value differently depending on the energy storage capacity of the tag. That is, if the tag's energy storage is sufficient, the slot number can be selected using the Q value provided by the reader as is. On the other hand, if the tag's energy storage is small, the slot number can be selected by applying only half of the Q value provided by the reader (e.g., Q / 2) or by using a specific offset value provided in advance by the reader (e.g., Q - offset).

[0273] As another example, if the priority of a specific tag is higher than that of other tags, the slot number can be selected by applying only half of the Q value provided by the reader (e.g., Q / 2), or by using a specific offset value provided in advance by the reader (e.g., Q - offset). On the other hand, if the priority of a tag is lower than that of other tags, the slot number can be selected using the Q value provided by the reader as is. Alternatively, a procedure for reporting the priority of a tag to the reader can be added, so that the reader can set / instruct different Q values ​​for each tag priority.

[0274] Additionally, during the initial transmission, the tag can select a slot number using the Q value provided by the reader. Furthermore, when the tag reselects a slot number after a collision, the tag can select a new slot number by changing the Q value based on the tag's priority or the tag's energy storage capacity, as suggested above.

[0275] A tag may need a criterion for determining whether its current energy storage is sufficient. Therefore, the reader can set / indicate a threshold for the tag's current energy level or the percentage of remaining energy out of its total energy storage. The threshold can be set / indicated on a per-device / tag basis or per-device / tag type basis. Alternatively, the threshold can be predefined, in which case it can also be set / indicated on a per-device / tag basis or per-device / tag type basis.

[0276] Here, if the current amount of energy or the ratio of remaining energy among the total energy storage is greater than or equal to the threshold, the tag can select an integer from 0 to 2^Q-1 as the slot number based on the Q value set / instructed from the reader and set it as the slot number count value. On the other hand, if the current amount of energy or the ratio of remaining energy among the total energy storage is less than the threshold, the tag can select a value smaller than the Q value set / instructed from the reader (e.g., R, R <Q)을 기반으로 슬롯 번호를 0부터 2^R-1 중 하나의 정수를 선택하여, 슬롯 번호 카운트 값으로 설정할 수 있다.

[0277] Alternatively, if the current amount of energy or the percentage of remaining energy in the total energy storage is below the threshold, the tag will output a value smaller than the Q value set / instructed by the reader (e.g. R, R <Q)을 기반으로 슬롯 번호를 0부터 2^R-1 중 하나의 정수를 선택하여, 슬롯 번호 카운트 값으로 설정할 수 있다. 반면, 현재 에너지의 양 또는 전체 energy storage 중 남은 에너지의 비율이 해당 임계치 이상일 경우, 슬롯 번호의 구간별로 서로 다른 확률을 사용하여 슬롯 번호를 선택하여, 슬롯 번호 카운트 값으로 설정할 수 있다. 예를 들어, 태그는 0부터 2^R-1 구간에선 P1의 확률을 적용하고, 2^R부터 2^Q-1 구간에선 P2의 확률(여기서, P1<P2 이고 P1+P2=1)을 적용하여 슬롯 번호를 선택할 수 있다.

[0278] Alternatively, the reader can indicate a threshold for the percentage of remaining energy out of the total energy storage. In this case, if the amount of energy remaining in the tag is less than the threshold, the tag can apply the threshold to the Q value to obtain a smaller Q' value, select a slot number based on the Q' value, and set it as the slot number count value. For example, assume that the reader indicates 70% as the threshold. In this case, if the amount of energy remaining in the tag is less than 70% of the total, the tag can select a new slot number based on the Q' value derived according to Q' = floor(0.7*Q)(floor(x) is the largest integer not greater than x) (or Q' = ceil(0.7*Q)(ceil(x) is the smallest integer not less than x)), and set it as the slot number count value.

[0279] Alternatively, if the reader has not set / indicated a separate threshold (or, tags whose remaining energy amount is less than a pre-indicated threshold), the tag can obtain a Q' value smaller than the Q value according to the remaining energy amount ratio, select a slot number based on the Q' value, and set it as the slot number count value. For example, if the reader has not set / indicated a separate threshold (or, the reader has instructed 60% as the threshold), if the remaining energy amount in the tag is 50% of the total, the tag can derive the Q' value by applying Q'= floor(0.5*Q) (or Q'= ceil(0.5*Q)), select a new slot number based on the Q' value, and set it as the slot number count value.

[0280] When a tag first enters an inventory round, the slot number counter can be determined using the Q value provided by the leader. However, when considering the operation in which the tag re-determines the slot number counter after a collision, the slot number counter can be determined based on different Q values ​​depending on the remaining energy, as suggested above. Alternatively, when considering the operation in which the tag re-determines the slot number counter after a collision, the slot number counter can be re-determined by applying different probabilities to each section of the slot number counter depending on the remaining energy.

[0281] Additionally, the threshold for determining whether energy storage is sufficient can be independently set based on the Q value set / instructed by the leader. That is, if the Q value is large, the threshold can be set large, and if the Q value is small, the threshold can be set small.

[0282] Also, depending on the Q value set / instructed by the leader, tags with energy storage below the threshold may select a value smaller than the Q value (e.g., R, R). <Q)도 독립적으로 설정될 수 있다. 만약, 특정 태그가 energy storage가 임계치 이하인 데도 불구하고, i) Q 값보다 더 작은 값(예를 들어, R, R<Q)을 사용하여 슬롯 번호 카운터를 결정하는 것이 허용되지 않는 경우, 또는 ii) 단말이 Q 값보다 더 작은 값(예를 들어, R, R<Q)을 사용하여 결정할 수 있는 값 보다 더 큰 값을 슬롯 번호 카운터로 결정하는 경우, 해당 태그는 인벤토리 라운드에서 msg1 전송 동작을 생략하거나, 그리고 / 또는 해당 태그의 상태를 슬립(sleep) 또는 에너지 수확(energy harvesting) 등으로 전환할 수 있다.

[0283] As described above, a tag can select a value lower than the Q value based on its energy storage / status, or determine whether it can participate in a specific inventory round by comparing the tag's energy recharge time with the time required for the inventory round. A reference time for this comparison can be defined.

[0284] For example, the minimum (or average) slot time 'T' occupied by one slot used in the Slotted ALOHA scheme can be defined. The time remaining until the tag is discharged based on the current energy balance can be defined as a*T, and the time required until full charging based on the current energy balance can be defined as b*T. In addition, the time required for the tag to complete an inventory round based on the slot number counter 'q' value selected / determined through the Q value set / instructed by the reader can be defined as (q+1)*T (where q is the slot number counter value and can be an integer from 0 to 2^Q-1).

[0285] Here, when calculating (q+1)*T based on the slot number counter value selected / determined by the tag, if the value of (q+1)*T is less than the remaining time a*T until discharge, the tag waits without performing energy harvesting, and when the slot number counter value becomes 0, it can transmit msg1.

[0286] On the other hand, if (q+1)*T is greater than or equal to the remaining time a*T until discharge, the tag can be defined to behave in one of two ways. The tag compares the time required to fully charge b*T with the value of (q+1)*T, and if b*T is less than or equal to (q+1)*T, it finishes charging through energy harvesting and can participate in the inventory round when the slot number counter becomes 0. On the other hand, if the time required to fully charge b*T is greater than (q+1)*T, the tag can skip this inventory round and continue performing energy harvesting, because the slot number counter selected / determined by the tag may become 0 before fully charged and msg1 may need to be transmitted.

[0287] Alternatively, based on the remaining time a*T until discharge and / or the time b*T required to fully charge based on the current energy balance, the tag can determine the Q' value and select the slot number counter value so that it can participate in the corresponding inventory round. For example, the tag can determine the Q' value so as to select / determine a slot number counter that can obtain a (q+1)*T value that is less than a*T value. Alternatively, the tag can determine the Q' value so as to select / determine a slot number counter that can obtain a (q+1)*T value that is greater than or equal to b*T value. Here, the methods for determining the Q' value can be determined in combination with each other, and additionally, a slot number counter that obtains a (q+1)*T that is less than or equal to b*T can be defined so that the tag does not select it.

[0288] Alternatively, the reader may set / instruct one or more time thresholds to the tags in advance. Accordingly, the tags can determine whether to participate in the current inventory round or the next inventory round based on their energy storage / status. For example, if the reader sets / instructs a time threshold corresponding to k*T, the tags can compare the remaining time a*T until discharge with the value of k*T and decide to participate in the current inventory round only if the value of a*T is greater. Here, the time thresholds can be set / instructed in units such as absolute time and / or slot number counter values, and can also be defined based on the start time of the inventory round (e.g., the time when a query command (or query adjustment) is received).

[0289] Meanwhile, the above threshold setting / instruction method can also be applied to the slot number counter setting method that the collided tag of Embodiment 2 can newly select. For example, when the collided tag selects a new slot number counter, if the current remaining energy ratio or remaining energy is greater than or equal to the threshold value indicated by the reader, the tag can select / determine a relatively larger number as the slot number. On the other hand, if the current remaining energy ratio or remaining energy is less than the corresponding threshold value, the tag can select / determine a relatively smaller number as the slot number. Specifically, based on the Q value indicated by the reader, if the energy state of the collided tag is less than the threshold value, the tag can select / determine one from 0 to 2^(Q-1)-1 as the new slot number counter. On the other hand, if the energy state of the collided tag is greater than or equal to the threshold value, the tag can select / determine one from 2^(Q-1) to 2^Q-1 as the new slot number counter.

[0290] Alternatively, tags may report to the leader a new Q' value (different from the Q value) that can be selected based on their residual energy percentage or residual energy storage / state. The leader may then determine / indicate the Q value for a particular inventory round based on the Q' values ​​collected from multiple tags.

[0291] For example, if multiple tags report that they can all select the same Q' value, the leader can set / indicate the Q' value as a common Q' value to be used in that inventory round. The tags can then determine / select a slot number counter based on that common Q' value.

[0292] As another example, if multiple tags report different Q' values, the reader can set / indicate which multiple Q' values ​​can be used in that inventory round, so that they can be selected based on energy storage / status or tag / device type.

[0293] As another example, if multiple tags report different Q' values, the reader can select the smallest value among the multiple Q' values ​​(i.e., min(Q')) and set / indicate it as the Q value of the inventory round. Then, if one Q value is set / indicated, the tag can use it to determine / select the slot number counter. On the other hand, if multiple Q values ​​are set / indicated, the tag can select a Q value based on the energy storage / state or the type of tag / device and use it to determine / select the slot number counter.

[0294] Example 4: How to use a back-off timer

[0295] Let's assume that a collision avoidance method using a back-off timer is introduced into the A-IoT system. Here, the reader can provide information to the tag for generating a back-off timer. For example, the reader can provide a maximum back-off (timer) value, and the tag can select one of the maximum back-off (timer) values ​​from 1 based on that value and set it as the back-off timer value. Thereafter, the tags automatically decrease the back-off timer value without receiving any additional commands from the reader. When the back-off timer reaches 0, the tag can transmit UL control information (e.g., a random number or UE-ID information). Here, the tag can additionally set an additional back-off timer value for collision handling. Here, similar to the method proposed above (considering the slot number counter), the reader can provide the maximum additional back-off timer value, or the tag can determine the maximum additional back-off timer value based on a previously selected back-off timer value. Here, the reader can set / instruct via DL payload (e.g., command, etc.) the time interval (e.g., X ms) to reduce the tag's backoff timer.

[0296] Meanwhile, an intermediate node (IN) can perform UL / DL transmission and reception with the base station during some time intervals and act as an A-IoT leader to transmit commands to tags during other time intervals. In this case, if the tag decreases the backoff timer on its own without any specific conditions, the backoff timers of many tags may already be 0 during the time interval in which the IN operates as a leader, which may increase the probability of collision. To prevent this, instead of the tag decreasing the backoff timer on its own without any specific conditions, the leader can set / instruct a specific time interval (e.g., a backoff window) in which the backoff timer is decreased. As a result, the tag can decrease the backoff timer only within the backoff window, and can hold the backoff timer outside the backoff window. Here, the backoff window time interval can be defined as the A-IoT communication interval that the base station sets / instructs to the IN. Alternatively, instead of holding the backoff timer based on a specific time window as described above, the leader may configure the operation of the instruction / command (e.g., hold(skip) / resume or start / stop or skip(hold)) on whether to run the backoff timer to be valid only within a predefined or time window operation set / indicated by IN.

[0297] Additionally, whether or not to use a back-off timer, etc., can be set / defined based on the tag's (energy storage) capability, the tag's priority, or the priority of the transmission to be transmitted by the tag.

[0298] For example, if the tag's (energy storage) capability is insufficient (or conversely, if there is room), the backoff timer, etc. may be used. On the other hand, if the tag's (energy storage) capability is sufficient (or conversely, if there is room), the backoff timer, etc. may not be used and may be set / defined to always return to the maximum value.

[0299] As another example, if the tag has a high priority, the backoff timer, etc. may be used. On the other hand, if the tag has a low priority, the backoff timer, etc. may not be used and may be set / defined to always return to the maximum value.

[0300] Additionally, in the above-described method, timer values ​​may be predefined / set based on capabilities and / or priorities. In this case, instead of returning to the maximum value, the timer may be set to return to a predefined / set value based on the tag's capabilities / priority, etc.

[0301] Alternatively, the interval at which the backoff timer is decremented may be adjusted (i.e., set differently) based on the tag's (energy storage) capability, the tag's priority, or the priority of the transmission the tag is to transmit.

[0302] Meanwhile, in a method that can be commonly applied to the methods proposed in the above-described embodiments 1 to 4, tags performing retransmission after a collision can generate a new random number value in the previously transmitted UL control information (e.g., random number or UE-ID information). That is, if the initial transmission collides, the tag can update the UL control information by removing the random number used in the initial transmission and generating a new random number for the retransmission.

[0303] Additionally, in the methods proposed in the above-described embodiments, in the slot number counter-based operation, the slot number counter may be decreased by 1 by receiving DL control (e.g., a command) from the reader, or may be decreased by 1 for every specific symbol interval (e.g., 1 A-IoT symbol, slot). Additionally, in the backoff timer-based operation, the timer may be decreased based on actual time (e.g., x ms), or may be decreased according to a specific symbol interval (e.g., 1 A-IoT symbol, slot).

[0304] Meanwhile, the slot number counter and / or backoff timer may be defined / configured to be decremented only within a specific time period (e.g., slot number counting window or backoff window) set / instructed by the leader (e.g., base station or IN).

[0305] FIG. 11 illustrates the operation of a device for collision control according to one embodiment of the present disclosure.

[0306] FIG. 11 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. 11 is provided for convenience of explanation and does not limit the scope of the present disclosure. Some step(s) illustrated in FIG. 11 may be omitted depending on circumstances and / or settings. 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 transmitted or received channels / signals / data / information, etc. in the memory (104 / 204).

[0307] 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.

[0308] In FIG. 11, the second device (e.g., a leader, a base station, an intermediate node) may be a device that transmits a carrier wave for energy harvesting or backscattering, and the first device (e.g., a tag, an A-IoT device) may be a device that responds with a backscattered signal based on the carrier wave.

[0309] Referring to FIG. 11, the first device receives a first transmission including first information for determining a slot number counter from the second device (S1101).

[0310] The first device transmits a second transmission to the second device based on the slot number counter (S1102).

[0311] For example, when the slot number counter is decremented to 0, the first device can transmit a second transmission to the second device. For example, the first device can receive a signal from the second device to decrement the slot number counter by 1, thereby decrementing the slot number counter, or can decrement the slot number counter at regular intervals.

[0312] The first device retransmits the second transmission based on the collision of the second transmission (S1103).

[0313] Here, the second transmission may be retransmitted based on an additional counter or backoff timer determined due to a collision. For example, if the additional counter or timer is decremented to 0, the first device may retransmit the second transmission to the second device. For example, the first device may receive a signal from the second device to decrement the additional counter by 1, thereby decrementing the additional counter, or may decrement the additional counter at regular intervals. As another example, the first device may decrement the backoff timer at regular intervals.

[0314] The value of the additional counter or timer may be determined based on additional information included in the first transmission or based on the slot number counter. Here, the additional information may be set differently for each channel of the second transmission or each session in which the second transmission is transmitted.

[0315] Whether or not the additional counter or timer is used may be determined based on the capabilities of the first device, the priority of the first device, or the priority of the second transmission. Here, based on the non-use of the additional counter or timer, the slot number counter may be set to the maximum value or a predetermined value due to a collision with the second transmission.

[0316] The additional counter value may also be determined based on the first information. In this case, the value of the first information may be adjusted (e.g., adjusted by half or by applying an offset) and applied to determine the additional counter value.

[0317] The maximum number of retransmissions of the second transmission can be set by the second device (e.g. by the first transmission).

[0318] The first information may be applied differently to determine the slot number counter depending on the capability and / or priority of the first device. Here, the value of the first information may be applied as is or adjusted (e.g., adjusted by half or by applying an offset) based on whether the energy storage of the first device is higher than a threshold or based on whether the priority of the first device is high. In addition, the threshold may be set based on the magnitude of the value of the first information.

[0319] FIG. 12 illustrates the operation of a device for collision control according to one embodiment of the present disclosure.

[0320] FIG. 12 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. 12 is provided for convenience of explanation and does not limit the scope of the present disclosure. Some of the step(s) illustrated in FIG. 12 may be omitted depending on the situation and / or setting. 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 the channels / signals / data / information, etc. to be transmitted or received, in the memory (104 / 204).

[0321] 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.

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

[0323] Referring to FIG. 12, the second device transmits a first transmission including first information for determining a slot number counter to the first device (S1201).

[0324] The second device receives a second transmission from the first device (S1202).

[0325] Here, the second transmission may be transmitted based on the slot number counter. For example, when the slot number counter is decremented to 0, the first device may transmit the second transmission to the second device. For example, the first device may receive a signal from the second device to decrement the slot number counter by 1, thereby decrementing the slot number counter, or may decrement the slot number counter at regular intervals.

[0326] Additionally, the second transmission may be retransmitted based on an additional counter or backoff timer determined due to a collision with the second transmission. For example, if the additional counter or timer is decremented to 0, the first device may retransmit the second transmission to the second device. For example, the first device may receive a signal from the second device to decrement the additional counter by 1, thereby decrementing the additional counter, or may decrement the additional counter at regular intervals. As another example, the first device may decrement the backoff timer at regular intervals.

[0327] The value of the additional counter or timer may be determined based on additional information included in the first transmission or based on the slot number counter. Here, the additional information may be set differently for each channel of the second transmission or each session in which the second transmission is transmitted.

[0328] Whether or not the additional counter or timer is used may be determined based on the capabilities of the first device, the priority of the first device, or the priority of the second transmission. Here, based on the non-use of the additional counter or timer, the slot number counter may be set to the maximum value or a predetermined value due to a collision with the second transmission.

[0329] The additional counter value may also be determined based on the first information. In this case, the value of the first information may be adjusted (e.g., adjusted by half or by applying an offset) and applied to determine the additional counter value.

[0330] The maximum number of retransmissions of the second transmission can be set by the second device (e.g. by the first transmission).

[0331] The first information may be applied differently to determine the slot number counter depending on the capability and / or priority of the first device. Here, the value of the first information may be applied as is or adjusted (e.g., adjusted by half or by applying an offset) based on whether the energy storage of the first device is higher than a threshold or based on whether the priority of the first device is high. In addition, the threshold may be set based on the magnitude of the value of the first information.

[0332] General devices to which the present disclosure may be applied

[0333] FIG. 13 illustrates a block diagram of a wireless communication device according to one embodiment of the present disclosure.

[0334] 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).

[0335] 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.

[0336] 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.

[0337] 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.

[0338] 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.

[0339] 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.

[0340] 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.

[0341] 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.

[0342] 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.

[0343] 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.

[0344] 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.

[0345] 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 receiving a first transmission from a second device by a first device, wherein the first transmission includes first information for determining a slot number counter; A step of transmitting a second transmission to the second device based on the slot number counter by the first device; and A step of retransmitting the second transmission based on the collision of the second transmission by the first device, A method in which the second transmission is retransmitted based on an additional counter or backoff timer determined due to a collision of the second transmission.

2. In paragraph 1, A method wherein the value of the additional counter or backoff timer is determined based on additional information included in the first transmission or based on the slot number counter.

3. In paragraph 2, A method wherein the additional information is set differently for each channel of the second transmission or each session through which the second transmission is transmitted.

4. In paragraph 1, A method wherein whether to use the additional counter or backoff timer is determined based on the capability of the first device, the priority of the first device, or the priority of the second transmission.

5. In paragraph 4, A method wherein the slot number counter is set to a maximum value or a predetermined value based on the second transmission colliding with the second transmission, based on the fact that the additional counter or backoff timer is not used.

6. In paragraph 1, A method wherein the additional counter value is determined based on the first information.

7. In paragraph 6, A method in which the value of the first information is adjusted and applied to determine the additional counter value.

8. In paragraph 1, A method wherein the maximum number of retransmissions of the second transmission is set by the second device.

9. In paragraph 1, A method wherein the first information is applied differently to determine the slot number counter depending on the capability and / or priority of the first device.

10. In paragraph 9, A method in which the value of the first information is applied as is or the value of the first information is adjusted and applied based on whether the energy storage of the first device is higher than a threshold or based on whether the priority of the first device is high.

11. In paragraph 10, A method wherein the threshold is set based on the size of the value of the first information.

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

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

14. 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: Receive a first transmission from a second device, wherein the first transmission includes first information for determining a slot number counter; transmitting a second transmission to the second device based on the slot number counter; and The second transmission is set to be retransmitted based on the collision of the second transmission, A first device, wherein the second transmission is retransmitted based on an additional counter or backoff timer determined due to a collision of the second transmission.

15. 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: Receive a first transmission from a second device, wherein the first transmission includes first information for determining a slot number counter; transmitting a second transmission to the second device based on the slot number counter; and Control to retransmit the second transmission based on the collision of the second transmission, A computer-readable medium wherein the second transmission is retransmitted based on an additional counter or backoff timer determined due to a collision of the second transmission.

16. 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 that perform operations based on being executed by said one or more processors, The above actions are: A step of receiving a first transmission from a second device, wherein the first transmission includes first information for determining a slot number counter; A step of transmitting a second transmission to the second device based on the slot number counter; and A step of retransmitting the second transmission based on the collision of the second transmission, A processing device in which the second transmission is retransmitted based on an additional counter or backoff timer determined due to a collision of the second transmission.

17. A step of transmitting a first transmission to a first device by a second device, wherein the first transmission includes first information for determining a slot number counter; and A step of receiving a second transmission from the first device by the second device, The second transmission is transmitted based on the slot number counter, A method in which the second transmission is retransmitted based on an additional counter or backoff timer determined due to a collision of the second transmission.

18. 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: Transmitting a first transmission to a first device, wherein the first transmission includes first information for determining a slot number counter; and is configured to receive a second transmission from the first device; The second transmission is transmitted based on the slot number counter, A second device, wherein the second transmission is retransmitted based on an additional counter or backoff timer determined due to a collision of the second transmission.

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