Method for controlling random access procedure of ambient internet of things apparatus and device thereof

Abstract

A method by which an ambient IoT terminal performs a random access procedure and a device may be provided, the method comprising the steps of: transmitting message 1 to a reader device through transmission resource information selected from among one or more pieces of resource information; receiving message 2 corresponding to message 1 from the reader device; transmitting message 3 to the reader device through a resource scheduled by message 2; and monitoring message 2 retransmitted in a monitoring window configured on the basis of monitoring window configuration information.

Description

Method and apparatus for controlling a random access procedure of an ambient IoT device

[0001] The present disclosure describes a random access operation of an ambient Internet of Things device.

[0002] In recent years, the Internet of Things (IoT) has attracted significant attention in the field of wireless communication. It is expected that an increasing number of objects will become interconnected to improve productivity efficiency and enhance the comfort of daily life. Further reducing the size, complexity, and power consumption of IoT devices enables the deployment of tens or even hundreds of billions of IoT devices for various applications, thereby providing added value across the entire value chain. However, it is impossible to power all IoT devices with batteries, and since batteries must be manually replaced or recharged, this can lead to high maintenance costs, serious environmental issues, and even safety risks for some use cases.

[0003] In this regard, efficient power consumption of IoT devices is required, and accordingly, there is a need for specific designs regarding methods to manage the energy of IoT devices more efficiently.

[0004] In particular, considering the energy efficiency of IoT devices, specific optimization of the random access procedure capable of establishing communication with the reader device is also required.

[0005] The present disclosure proposes a method and apparatus for controlling random access operations of an ambient Internet of Things device.

[0006] In one aspect, the present embodiments may provide a method for an ambient IoT terminal to perform a random access procedure, comprising the steps of: transmitting message 1 to a reader device through transmission resource information selected from one or more resource information; receiving message 2 corresponding to message 1 from the reader device; transmitting message 3 to a reader device through a resource scheduled by message 2; and monitoring message 2 retransmitted in a monitoring window set based on monitoring window setting information.

[0007] In another aspect, the present embodiments may provide a method for a reader device to control a random access procedure of an ambient IoT terminal, comprising the steps of: receiving a message 1 from an ambient IoT terminal through transmission resource information selected from one or more resource information; transmitting a message 2 corresponding to message 1 to the ambient IoT terminal; monitoring the reception of a message 3 through a resource scheduled by message 2; and, if message 3 is not received, retransmitting message 2 in a monitoring window set based on monitoring window setting information.

[0008] In another aspect, the embodiments may provide an ambient IoT terminal device that performs a random access procedure, comprising: a transmitting unit that transmits message 1 to a reader device through transmission resource information selected from one or more resource information; a receiving unit that receives message 2 corresponding to message 1 from the reader device; and a control unit that monitors message 2 retransmitted in a monitoring window based on monitoring window setting information after transmitting message 3 transmitted through a resource scheduled by message 2.

[0009] In another aspect, the embodiments may provide a reader device for controlling a random access procedure of an ambient IoT terminal, comprising: a receiving unit that receives a message 1 from an ambient IoT terminal through transmission resource information selected from one or more resource information; a transmitting unit that transmits a message 2 corresponding to message 1 to the ambient IoT terminal; and a control unit that monitors the reception of a message 3 through a resource scheduled by message 2, wherein if message 3 is not received, the transmitting unit retransmits message 2 in a monitoring window set based on monitoring window setting information.

[0010] The present disclosure may provide a method and apparatus for controlling and completing random access operations of an ambient Internet of Things device.

[0011] FIG. 1 is a diagram briefly illustrating the structure of an NR wireless communication system to which the present embodiment can be applied.

[0012] FIG. 2 is a drawing illustrating the frame structure in an NR system to which the present embodiment can be applied.

[0013] FIG. 3 is a diagram illustrating a resource grid supported by wireless access technology to which the present embodiment can be applied.

[0014] FIG. 4 is a diagram illustrating the bandwidth part supported by the wireless access technology to which the present embodiment can be applied.

[0015] FIG. 5 is a diagram illustrating an exemplary synchronization signal block in a wireless access technology to which the present embodiment can be applied.

[0016] FIG. 6 is a diagram illustrating a random access procedure in a wireless access technology to which the present embodiment can be applied.

[0017] Figure 7 is a diagram for explaining CORESET.

[0018] FIG. 8 is a diagram illustrating the MSG3 retransmission operation in a random access procedure according to one embodiment.

[0019] FIG. 9 is a diagram illustrating the operation of an ambient IoT terminal according to one embodiment.

[0020] FIG. 10 is a drawing for explaining the operation of a reader device according to one embodiment.

[0021] FIG. 11 is a diagram illustrating a message 2 monitoring operation according to one embodiment.

[0022] FIG. 12 is a diagram illustrating offset information for synchronizing a monitoring window start point according to one embodiment.

[0023] FIG. 13 is a diagram illustrating random access operation according to a monitoring window setting according to one embodiment.

[0024] FIG. 14 is a diagram illustrating random access operation according to a monitoring window setting according to another embodiment.

[0025] FIG. 15 is a diagram illustrating the configuration of an ambient IoT terminal according to one embodiment.

[0026] FIG. 16 is a drawing for explaining the configuration of a reader device according to one embodiment.

[0027] Hereinafter, some embodiments of the present disclosure will be described in detail with reference to the exemplary drawings. In assigning reference numerals to the components of each drawing, the same components may have the same reference numeral as much as possible, even if they are shown in different drawings. Furthermore, in describing the embodiments, if it is determined that a detailed description of related known components or functions may obscure the essence of the technical concept, such detailed description may be omitted. Where terms such as "comprising," "having," or "consisting of" are used in this specification, other parts may be added unless "only" is used. Where a component is expressed in the singular, it may include a plural unless otherwise specified.

[0028] Additionally, terms such as first, second, A, B, (a), (b), etc., may be used to describe the components of the present disclosure. These terms are used merely to distinguish the components from other components, and the nature, order, sequence, or number of the components are not limited by such terms.

[0029] In describing the positional relationship of components, where it is stated that two or more components are "connected," "combined," or "joined," it should be understood that while the two or more components may be directly "connected," "combined," or "joined," they may also be "connected," "combined," or "joined" with other components "intervened." Here, the other components may be included in one or more of the two or more components that are "connected," "combined," or "joined" with one another.

[0030] In describing the temporal flow relationship regarding components, methods of operation, or methods of production, for example, when the temporal or sequential relationship is described using "after," "following," "next," or "before," it may include cases where the relationship is not continuous unless "immediately" or "directly" is used.

[0031] Meanwhile, where numerical values ​​or corresponding information regarding a component (e.g., levels, etc.) are mentioned, even without separate explicit notation, the numerical values ​​or corresponding information may be interpreted as including a range of error that may occur due to various factors (e.g., process factors, internal or external shocks, noise, etc.).

[0032]

[0033] A wireless communication system in this specification refers to a system for providing various communication services, such as voice and data packets, using wireless resources, and may include a terminal, a base station, or a core network.

[0034] The embodiments disclosed below may be applied to wireless communication systems using various wireless access technologies. For example, the embodiments may be applied to various wireless access technologies such as CDMA (code division multiple access), FDMA (frequency division multiple access), TDMA (time division multiple access), OFDMA (orthogonal frequency division multiple access), SC-FDMA (single carrier frequency division multiple access), or NOMA (non-orthogonal multiple access). Furthermore, wireless access technology may refer not only to specific access technologies but also to communication technologies for each generation established by various telecommunication organizations such as 3GPP, 3GPP2, WiFi, Bluetooth, IEEE, and ITU. For example, CDMA may be implemented as a wireless technology such as UTRA (universal terrestrial radio access) or CDMA2000. TDMA may be implemented as a wireless technology such as GSM (global system for mobile communications), GPRS (general packet radio service), or EDGE (enhanced datarates for GSM evolution). OFDMA can be implemented using wireless technologies such as IEEE (Institute of Electrical and Electronic Engineers) 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802-20, and E-UTRA (evolved UTRA). IEEE 802.16m is an evolution of IEEE 802.16e and provides backward compatibility with systems based on IEEE 802.16e.UTRA is part of UMTS (universal mobile telecommunications system). 3GPP (3rd generation partnership project) LTE (long term evolution) is part of E-UMTS (evolved UMTS) that uses E-UTRA (evolved-UMTS terrestrial radio access), employing OFDMA in the downlink and SC-FDMA in the uplink. As such, these embodiments can be applied to currently disclosed or commercialized radio access technologies, and can also be applied to radio access technologies currently under development or to be developed in the future.

[0035] Meanwhile, the term "terminal" in this specification is a comprehensive concept meaning a device including a wireless communication module that communicates with a base station in a wireless communication system. It should be interpreted as a concept that includes not only User Equipment (UE) in WCDMA, LTE, NR, HSPA, and IMT-2020 (5G or New Radio), but also Mobile Station (MS), User Terminal (UT), Subscriber Station (SS), and wireless device in GSM. Furthermore, depending on the usage type, the terminal may be a user portable device such as a smartphone, or in a V2X communication system, it may refer to a vehicle or a device including a wireless communication module inside a vehicle. Additionally, in the case of a Machine Type Communication (MMC) system, it may refer to an MTC terminal, M2M terminal, URLLC terminal, etc., equipped with a communication module to perform machine type communication.

[0036] In this specification, "base station" or "cell" refers to an end that communicates with a terminal in terms of a network, and encompasses various coverage areas such as Node-B, eNB (evolved Node-B), gNB (gNode-B), LPN (Low Power Node), Sector, Site, various types of antennas, BTS (Base Transceiver System), Access Point, Point (e.g., Transmitter Point, Receiver Point, Transceiver Point), Relay Node, Mega Cell, Macro Cell, Micro Cell, Pico Cell, Femto Cell, RRH (Remote Radio Head), RU (Radio Unit), and Small Cell. Additionally, "cell" may include a Bandwidth Part (BWP) in the frequency domain. For example, a serving cell may refer to the Activation BWP of a terminal.

[0037] Since there is a base station controlling one or more of the various cells listed above, the term "base station" can be interpreted in two senses. 1) It may refer to the device itself that provides a mega cell, macro cell, micro cell, pico cell, femto cell, or small cell in relation to a wireless area, or 2) it may refer to the wireless area itself. In 1), all devices that provide a specific wireless area are controlled by the same entity or interact to configure the wireless area collaboratively are referred to as base stations. Depending on the configuration method of the wireless area, a point, a transmitting / receiving point, a transmitting point, a receiving point, etc., are examples of a base station. In 2), the wireless area itself that receives or transmits a signal from the perspective of a user terminal or from the perspective of a neighboring base station may also be referred to as a base station.

[0038] In this specification, "Cell" may refer to a component carrier having coverage of a signal transmitted from a transmitting / receiving point or coverage of a signal transmitted from a transmitting / receiving point (transmission point or transmission / reception point), or the transmitting / receiving point itself.

[0039] Uplink (UL, or Uplink) refers to the method of transmitting and receiving data from a terminal to a base station, and Downlink (DL, or Downlink) refers to the method of transmitting and receiving data from a base station to a terminal. Downlink may refer to communication or a communication path from multiple transmission and reception points to a terminal, and uplink may refer to communication or a communication path from a terminal to multiple transmission and reception points. In this case, in the downlink, the transmitter may be part of the multiple transmission and reception points, and the receiver may be part of the terminal. Additionally, in the uplink, the transmitter may be part of the terminal, and the receiver may be part of the multiple transmission and reception points.

[0040] The uplink and downlink transmit and receive control information through control channels such as PDCCH (Physical Downlink Control Channel) and PUCCH (Physical Uplink Control Channel), and transmit and receive data by configuring data channels such as PDSCH (Physical Downlink Shared Channel) and PUSCH (Physical Uplink Shared Channel). In the following, the situation in which signals are transmitted and received through channels such as PUCCH, PUSCH, PDCCH, and PDSCH is also indicated in the form of "transmitting and receiving PUCCH, PUSCH, PDCCH, and PDSCH."

[0041] To clarify the explanation, the technical concept described below is primarily based on 3GPP LTE / LTE-A / NR (New RAT) communication systems, but the technical features are not limited to said communication systems.

[0042] Following research on 4G (4th-Generation) communication technology, 3GPP develops 5G (5th-Generation) communication technology to meet the requirements of the ITU-R for next-generation radio access technology. Specifically, 3GPP develops LTE-A pro, which enhances LTE-Advanced technology to meet ITU-R requirements, and NR, a new communication technology distinct from 4G communication technology, as 5G communication technologies. Since both LTE-A pro and NR refer to 5G communication technology, the following explanation of 5G communication technology will focus on NR unless a specific technology is being identified.

[0043] The operational scenarios in NR define various operation scenarios by adding considerations for satellites, automobiles, and new verticals to the existing 4G LTE scenarios, and in terms of service, they support eMBB (Enhanced Mobile Broadband) scenarios, mMTC (Massive Machine Communication) scenarios which require low data rates and asynchronous access while having high terminal density and being deployed over a wide range, and URLLC (Ultra Reliability and Low Latency) scenarios which require high responsiveness and reliability and can support high-speed mobility.

[0044] To satisfy these scenarios, NR introduces a wireless communication system equipped with new waveform and frame structure technologies, low latency technology, mmWave support technology, and forward compatibility technology. In particular, the NR system presents various technical changes in terms of flexibility to provide forward compatibility. The main technical features of NR are explained below with reference to the drawings.

[0045]

[0046] <NR 시스템 일반>

[0047] FIG. 1 is a simplified diagram illustrating the structure of an NR system to which the present embodiment can be applied.

[0048] Referring to FIG. 1, the NR system is divided into a 5G Core Network (5GC) and an NR-RAN part. The NG-RAN consists of gNBs and ng-eNBs that provide control plane (RRC) protocol endpoints for the user plane (SDAP / PDCP / RLC / MAC / PHY) and User Equipment (UE). gNBs are interconnected with each other, or gNBs and ng-eNBs are interconnected via Xn interfaces. Each gNB and ng-eNB is connected to the 5GC via an NG interface. The 5GC may be configured to include an Access and Mobility Management Function (AMF), which is responsible for control plane functions such as terminal access and mobility control, and a User Plane Function (UPF), which is responsible for control functions for user data. The NR includes support for both frequency bands below 6 GHz (FR1, Frequency Range 1) and frequency bands above 6 GHz (FR2, Frequency Range 2).

[0049] gNB refers to a base station that provides NR user plane and control plane protocol terminations to a terminal, and ng-eNB refers to a base station that provides E-UTRA user plane and control plane protocol terminations to a terminal. The base station described in this specification should be understood as encompassing both gNB and ng-eNB, and may be used to refer to gNB or ng-eNB separately as needed.

[0050] <NR 웨이브 폼,뉴머롤러지 및 프레임 구조>

[0051] In NR, CP-OFDM waveforms using a cyclic prefix are used for downlink transmission, and CP-OFDM or DFT-s-OFDM are used for uplink transmission. OFDM technology is easy to combine with MIMO (Multiple Input Multiple Output) and has the advantage of allowing the use of low-complexity receivers along with high frequency efficiency.

[0052] Meanwhile, in NR, since the requirements for data rate, latency, coverage, etc. differ for each of the three scenarios mentioned above, it is necessary to efficiently satisfy the requirements for each scenario through the frequency bands that constitute an arbitrary NR system. To this end, a technology has been proposed to efficiently multiplex wireless resources based on multiple different numerologies.

[0053] Specifically, the NR transmission numerator is determined based on sub-carrier spacing and CP (Cyclic prefix), and as shown in Table 1 below, the μ value is used as an exponential value of 2 based on 15 kHz and changes exponentially.

[0054] μsubcarrier intervalCyclic prefixSupported for dataSupported for synch015NormalYesYes130NormalYesYes260Normal, ExtendedYesNo3120NormalYesYes4240NormalNoYes

[0055] As shown in Table 1 above, the numerators of NR can be classified into five types based on the subcarrier spacing. This differs from LTE, one of the 4G communication technologies, where the subcarrier spacing is fixed at 15 kHz. Specifically, the subcarrier spacings used for data transmission in NR are 15, 30, 60, and 120 kHz, while the subcarrier spacings used for synchronization signal transmission are 15, 30, 120, and 240 kHz. Additionally, extended CP is applied only to the 60 kHz subcarrier spacing. Meanwhile, the frame structure in NR defines a frame with a length of 10 ms, composed of 10 subframes of equal length of 1 ms. A single frame can be divided into 5 ms half-frames, and each half-frame contains 5 subframes. In the case of a 15 kHz subcarrier spacing, one subframe consists of one slot, and each slot consists of 14 OFDM symbols. FIG. 2 is a diagram illustrating the frame structure in an NR system to which the present embodiment can be applied.

[0056] Referring to Fig. 2, in the case of a normal CP, the slot is fixedly composed of 14 OFDM symbols, but the length of the slot in the time domain may vary depending on the subcarrier spacing. For example, in the case of a numeral with a 15 kHz subcarrier spacing, the slot is composed of a length of 1 ms, which is the same length as the subframe. In contrast, in the case of a numeral with a 30 kHz subcarrier spacing, the slot is composed of 14 OFDM symbols, but two slots may be included in one subframe with a length of 0.5 ms. That is, the subframe and the frame are defined with a fixed time length, while the slot is defined by the number of symbols and the time length may vary depending on the subcarrier spacing.

[0057] Meanwhile, NR defines the basic unit of scheduling as a slot and introduced mini-slots (or sub-slots or non-slot based schedules) to reduce transmission delay in the wireless section. Using a wide subcarrier spacing reduces transmission delay in the wireless section because the length of a single slot becomes inversely shorter. Mini-slots (or sub-slots) are designed for efficient support of URLLC scenarios and allow scheduling in units of 2, 4, or 7 symbols.

[0058] Furthermore, unlike LTE, NR defines uplink and downlink resource allocation at the symbol level within a single slot. To reduce HARQ latency, a slot structure was defined that allows HARQ ACK / NACK to be transmitted directly within the transmission slot; this slot structure is described as a self-contained structure.

[0059] NR is designed to support a total of 256 slot formats, of which 62 are used in 3GPP Rel-15. Additionally, it supports common frame structures that form FDD or TDD frames through various slot combinations. For example, it supports slot structures where all slot symbols are set to downlink, slot structures where all symbols are set to uplink, and slot structures where downlink and uplink symbols are combined. Furthermore, NR supports data transmission being distributed and scheduled across one or more slots. Therefore, base stations can use a Slot Format Indicator (SFI) to inform a terminal whether a slot is a downlink slot, an uplink slot, or a flexible slot. Base stations can indicate the slot format by using the SFI to indicate an index of a table configured via UE-specific RRC signaling, or they can indicate it dynamically via Downlink Control Information (DCI) or statically or semi-statically via RRC.

[0060] <NR 물리 자원 >

[0061] Regarding physical resources in NR, antenna ports, resource grids, resource elements, resource blocks, and bandwidth parts are considered.

[0062] An antenna port is defined such that the channel carrying a symbol on the antenna port can be inferred from the channel carrying another symbol on the same antenna port. If the large-scale property of the channel carrying a symbol on one antenna port can be inferred from the channel carrying a symbol on another antenna port, the two antenna ports can be said to be in a QC / QCL (quasi-co-located or quasi-co-location) relationship. Here, the large-scale property includes one or more of delay spread, Doppler spread, frequency shift, average received power, and received timing.

[0063] FIG. 3 is a diagram illustrating a resource grid supported by wireless access technology to which the present embodiment can be applied.

[0064] Referring to FIG. 3, a resource grid may exist for each numerator because NR supports multiple numerators on the same carrier. Additionally, a resource grid may exist depending on the antenna port, subcarrier spacing, and transmission direction.

[0065] A resource block consists of 12 subcarriers and is defined only in the frequency domain. Additionally, a resource element consists of one OFDM symbol and one subcarrier. Therefore, as shown in Fig. 3, the size of a single resource block can vary depending on the subcarrier spacing. Furthermore, NR defines "Point A," which serves as a common reference point for the resource block grid, as well as common resource blocks, virtual resource blocks, etc.

[0066] FIG. 4 is a diagram illustrating the bandwidth part supported by the wireless access technology to which the present embodiment can be applied.

[0067] In NR, unlike LTE where the carrier bandwidth is fixed at 20 MHz, the maximum carrier bandwidth is set from 50 MHz to 400 MHz depending on the subcarrier interval. Therefore, it is not assumed that all terminals use this entire carrier bandwidth. Accordingly, in NR, as shown in Fig. 4, a Bandwidth Part (BWP) can be designated within the carrier bandwidth for the terminal to use. Additionally, a Bandwidth Part is associated with a single numerator and consists of a subset of a continuous common resource block, and can be dynamically activated over time. Up to four Bandwidth Parts are configured for the uplink and downlink respectively, and data is transmitted and received using the Bandwidth Part activated at a given time.

[0068] In the case of paired spectrum, the uplink and downlink bandwidth parts are set independently, whereas in the case of unpaired spectrum, the downlink and uplink bandwidth parts are paired to share a center frequency in order to prevent unnecessary frequency re-tuning between downlink and uplink operations.

[0069] <NR 초기 접속>

[0070] In NR, the terminal performs cell search and random access procedures to connect to the base station and perform communication.

[0071] Cell search is a procedure in which a terminal uses a Synchronization Signal Block (SSB) transmitted by a base station to synchronize with the corresponding base station's cell, obtain a physical layer cell ID, and acquire system information.

[0072] FIG. 5 is a diagram illustrating an exemplary synchronization signal block in a wireless access technology to which the present embodiment can be applied.

[0073] Referring to FIG. 5, the SSB consists of a primary synchronization signal (PSS) and a secondary synchronization signal (SSS) each occupying 1 symbol and 127 subcarriers, and a PBCH spanning 3 OFDM symbols and 240 subcarriers.

[0074] The terminal monitors the SSB in the time and frequency domains and receives the SSB.

[0075] SSBs can be transmitted up to 64 times within 5ms. Multiple SSBs are transmitted via different transmission beams within the 5ms timeframe, and the terminal performs detection by assuming that an SSB is transmitted every 20ms based on a specific beam used for transmission. The number of beams available for SSB transmission within the 5ms timeframe can increase as the frequency band increases. For example, up to 4 SSB beams can be transmitted at 3GHz or lower, up to 8 beams in the frequency band from 3GHz to 6GHz, and up to 64 different beams can be used to transmit SSBs in the frequency band above 6GHz.

[0076] Two SSBs are included in a single slot, and the starting symbol and number of repetitions within the slot are determined according to the subcarrier interval as follows.

[0077] Meanwhile, unlike the SS of conventional LTE, the SSB is not transmitted at the center frequency of the carrier bandwidth. That is, the SSB can be transmitted even at locations other than the center of the system band, and multiple SSBs can be transmitted across the frequency domain when broadband operation is supported. Accordingly, the terminal monitors the SSB using a synchronization raster, which is a candidate frequency location for monitoring the SSB. The carrier raster, which is information on the center frequency location of the channel for initial connection, and the synchronization raster were newly defined in NR, and the synchronization raster is set with a wider frequency interval compared to the carrier raster, thereby supporting fast SSB search by the terminal.

[0078] The terminal can obtain the MIB through the SSB's PBCH. The Master Information Block (MIB) contains minimum information for the terminal to receive the Remaining Minimum System Information (RMSI) broadcast by the network. Additionally, the PBCH may include information regarding the location of the first DM-RS symbol in the time domain, information for the terminal to monitor SIB1 (e.g., SIB1 numeral information, information related to SIB1 CORESET, search space information, PDCCH related parameter information, etc.), and offset information between the Common Resource Block and the SSB (the absolute location of the SSB within the carrier is transmitted via SIB1). Here, the SIB1 numeral information is applied identically to some messages used in the random access procedure for the terminal to connect to the base station after completing the cell search procedure. For example, the SIB1 numeral information may be applied to at least one of messages 1 to 4 for the random access procedure.

[0079] The aforementioned RMSI may refer to SIB1 (System Information Block 1), and SIB1 is broadcast periodically (e.g., 160ms) from the cell. SIB1 contains information necessary for the terminal to perform the initial random access procedure and is transmitted periodically via PDSCH. To receive SIB1, the terminal must receive the numerology information used for transmitting SIB1 and the CORESET (Control Resource Set) information used for scheduling SIB1 via PBCH. The terminal checks the scheduling information for SIB1 using SI-RNTI within the CORESET and obtains SIB1 on the PDSCH according to the scheduling information. The remaining SIBs, excluding SIB1, may be transmitted periodically or upon the terminal's request.

[0080] FIG. 6 is a diagram illustrating a random access procedure in a wireless access technology to which the present embodiment can be applied.

[0081] Referring to FIG. 6, when cell search is completed, the terminal transmits a random access preamble for random access to the base station. The random access preamble is transmitted via PRACH. Specifically, the random access preamble is transmitted to the base station via PRACH, which consists of a series of radio resources in specific slots that are repeated periodically. Generally, when the terminal initially connects to a cell, a contention-based random access procedure is performed, and when performing random access for Beam Failure Recovery (BFR), a non-contention-based random access procedure is performed.

[0082] The terminal receives a random access response for the transmitted random access preamble. The random access response may include a random access preamble identifier (ID), an UL Grant (uplink radio resource), a temporary C-RNTI (Temporary Cell - Radio Network Temporary Identifier), and a TAC (Time Alignment Command). Since a single random access response may contain random access response information for one or more terminals, the random access preamble identifier may be included to indicate which terminal the included UL Grant, temporary C-RNTI, and TAC are valid for. The random access preamble identifier may be an identifier for the random access preamble received by the base station. The TAC may be included as information for the terminal to coordinate uplink synchronization. The random access response may be indicated by the random access identifier on the PDCCH, namely the RA-RNTI (Random Access - Radio Network Temporary Identifier).

[0083] A terminal that receives a valid random access response processes the information contained in the random access response and performs a transmission scheduled to the base station. For example, the terminal applies a TAC and stores a temporary C-RNTI. Additionally, using a UL Grant, it transmits data stored in the terminal's buffer or newly generated data to the base station. In this case, information that can identify the terminal must be included.

[0084] Finally, the terminal receives a downlink message to resolve competition.

[0085] <NR CORESET>

[0086] The downlink control channel in NR is transmitted in a CORESET (Control Resource Set) with a length of 1 to 3 symbols, and transmits uplink / downlink scheduling information, SFI (Slot format Index), TPC (Transmit Power Control) information, etc.

[0087] In this way, NR introduced the concept of CORESET to ensure system flexibility. CORESET (Control Resource Set) refers to time-frequency resources for downlink control signals. A terminal can decode control channel candidates by using one or more search spaces from the CORESET time-frequency resources. Quasi CoLocation (QCL) assumptions were established for each CORESET, and these are used to indicate characteristics regarding the analog beam direction in addition to the characteristics assumed by conventional QCL, such as delay spread, Doppler spread, Doppler shift, and mean delay.

[0088] Figure 7 is a diagram for explaining CORESET.

[0089] Referring to FIG. 7, CORESET can exist in various forms within a single slot and within the carrier bandwidth, and in the time domain, CORESET can be composed of up to 3 OFDM symbols. Additionally, CORESET is defined as a multiple of 6 resource blocks up to the carrier bandwidth in the frequency domain.

[0090] The first CORESET is specified via the MIB as part of the initial bandwidth part configuration to enable the reception of additional configuration and system information from the network. After establishing a connection with the base station, the terminal can be configured by receiving one or more CORESET information via RRC signaling.

[0091] In this specification, frequencies, frames, subframes, resources, resource blocks, regions, bands, subbands, control channels, data channels, synchronization signals, various reference signals, various signals, or various messages related to NR (New Radio) may be interpreted in the sense used in the past or present, or in various senses used in the future.

[0092]

[0093] The ambient IoT terminal described in this specification may refer to an Internet of Things device. In this disclosure, IoT devices that support battery-less or energy harvesting are described as IoT terminals, terminals, ambient IoT terminals, etc., for the convenience of explanation and should be understood as devices that communicate with other devices. Meanwhile, descriptions such as ambient IoT terminal, IoT terminal, IoT device, terminal, A-IoT, etc., may be understood as referring to the same device.

[0094] In addition, the device that communicates with the aforementioned ambient IoT terminal is described as a reader device or reader, etc.

[0095] Use cases and scenarios for IoT devices that support battery-less or energy harvesting are being studied. Technologies are also being researched to support IoT devices with higher requirements that cannot be met by existing IoT technologies.

[0096] 3GPP suggests that Slotted Aloha may be proposed as a data transmission method for Ambient-IoT (A-IoT) devices. Slotted Aloha is a method in which data transmission is attempted from the beginning of a slot based on one or more slots, and a collision occurs if one or more devices transmit data simultaneously in the same slot. In this case, the device that detects the collision selects one of the next slots to retry data transmission.

[0097] To increase resource efficiency, one or more RO (RACH Occasion) or AO (Access Occasion) may be set within a single slot. That is, it provides multiple access methods in the frequency domain as well as resources in the time domain. This means that an A-IoT device can set i*j distinct access occasions using i time resources and j frequency resources in a single time slot resource area, and can select a competing resource based on time and frequency resources.

[0098] Accordingly, the reader device can receive multiple messages 1 (Msg1) from multiple A-IoT devices within a single slot and send message 2 (Msg2) in response.

[0099] For example, Msg 2 can be sent with the following two options. Additionally, a time interval for monitoring Msg 2 may be set according to each Msg 2 sending option.

[0100] For example, a PRDCH for transmitting Msg2 can be transmitted in response to an A-IoT Msg1 received on one device. As another example, a PRDCH for transmitting Msg2 can be transmitted in response to multiple A-IoT Msg1s received on multiple devices.

[0101] Meanwhile, in the case of an A-IoT terminal, there may be instances where Msg 3 is transmitted but the reader device fails to receive it. In such cases, the reader device may retransmit Msg 2 to trigger the retransmission of Msg 3. For example, if Msg 3 is not received by only some of the multiple A-IoT terminals, the reader device may control the retransmission of Msg 3 by retransmitting Msg 2 only to the corresponding terminals.

[0102] The present disclosure proposes a method for establishing contention resources based on multiple access methods in the time and frequency domains for IoT device(s) transmitting data in a Slotted Aloha manner, and for monitoring a second MSG2 for MSG3 transmission when the first MSG2 for MSG1 transmitted by any IoT device is successfully received.

[0103] FIG. 8 is a diagram illustrating the MSG3 retransmission operation in a random access procedure according to one embodiment.

[0104] Referring to FIG. 8, contention resources for the transmission of Msg1 can be established for an A-IoT terminal by considering not only TDMA but also FDMA. Based on this, data transmission and reception for the A-IoT device can be performed. Within a single time slot, a total of i*j access occasions can be established through i time resources and j frequency resources. In this case, a Reader device that receives two or more Msg1s distinguished by different time / frequency resources can transmit up to i*j different Msg2s in response. If the A-IoT device successfully receives Msg2 corresponding to the Msg1 it transmitted, it can transmit Msg3 through the resource indicated in Msg2 or a predefined resource. However, if the reader device fails to receive the expected Msg3 from the device that transmitted Msg2, the reader device can cause the device to retransmit Msg3 by retransmitting Msg2 to that device.

[0105] For example, RO resources can be configured on an A-IoT terminal via the PRDCH (Physical Reader to Device Channel). When six RO resources are configured, different terminals can transmit MSG1 from each RO. One A-IoT terminal selects one RO and transmits MSG1. The reader device transmits MSG2 to each A-IoT terminal that has received Msg1, distinguishing them by time resource. The A-IoT terminal that has received MSG2 transmits MSG3 through the resource indicated by Msg2 to perform a random access procedure. However, the reader device may fail to receive some MSG3. This may be due to various causes, such as the failure to receive MSG3 for various reasons like insufficient power to the A-IoT terminal, as well as the failure of the A-IoT terminal to receive Msg2 normally.

[0106] If two MSG3s are not received, the reader device retransmits the MSG2 corresponding to the unreceived MSG3s. The A-IoT terminal retransmits the MSG3 corresponding to the MSG2. If the MSG3 corresponding to the #1 MSG1 resource is not received, the reader device retransmits the MSG2 once again.

[0107] Accordingly, an A-IoT device that has transmitted MSG3 needs to additionally verify the successful transmission of the MSG3 it sent by checking for the retransmission of MSG2 after the MSG3 transmission. Therefore, just as the MSG2 monitoring duration is set based on the transmission of MSG1, a specific configuration method is required for setting the MSG2 monitoring duration after the transmission of MSG3. In other words, a method for setting the MSG2 monitoring duration that can be configured based on MSG3 needs to be concretized.

[0108] Accordingly, in this disclosure, in order to efficiently use overall system resources and minimize the power consumption of the device, it is necessary to define an MSG 2 monitoring method for MSG3 retransmission of the terminal and the operation of the device and reader device for MSG2 re-reception.

[0109]

[0110] FIG. 9 is a diagram illustrating the operation of an ambient IoT terminal according to one embodiment.

[0111] Referring to FIG. 9, a method for an ambient IoT terminal to perform a random access procedure may include the step of transmitting message 1 to a reader device through selected transmission resource information among one or more resource information (S910).

[0112] For example, an ambient IoT terminal can transmit Message 1 to a reader device to perform a random access procedure. Message 1 can be transmitted through any transmission resource information selected from one or more resource information set by the reader device. Message 1 is transmitted through the PDRCH (Physical Device to Reader Channel).

[0113] One or more resource information can be received through a connection opportunity resource setting message transmitted by a reader device. One or more resources may consist of multiple resources distinguished by time and frequency axes. An ambient IoT terminal can randomly select a resource among the multiple resources to transmit message 1.

[0114] Message 1 may include a random number. The random number is set to 16 bits and can be randomly selected and configured by an ambient IoT terminal. Through this, when multiple ambient IoT terminals transmit Message 1 using the same resource information, the ambient IoT terminals can be distinguished.

[0115] A method for performing a random access procedure may include the step of receiving message 2 corresponding to message 1 from a reader device (S920).

[0116] For example, Message 2 corresponding to Message 1 may be delivered to an Ambient IoT terminal. A reader device may receive Message 1, verify the random access procedure of the Ambient IoT terminal, and transmit Message 2 corresponding to Message 1. Message 2 may include scheduling information for the Ambient IoT terminal to schedule the transmission resources for Message 3 to transmit Message 3. Alternatively, Message 2 may include a random number that was included in Message 1. Through this, the Ambient IoT terminal can confirm that Message 2 corresponding to the transmission of Message 1 has been received.

[0117] An ambient IoT terminal can monitor whether Message 2 has been received within a monitoring period to receive Message 2. The monitoring period may be determined based on the count information of one or more resource information. For example, the monitoring period may be set in correspondence with one or more resource information for the transmission of Message 1. To this end, an index may be assigned and transmitted for each of the one or more resource information for the transmission of Message 1. Alternatively, the monitoring period may start after a certain time based on the end point of the Message 1 transmission resource, and the end point may be determined based on the unit time information for transmitting Message 2 and the count information of one or more resource information. For example, the time when the transmission resource for Message 1 ends and a certain offset has elapsed may be set as the start point of the monitoring period. Additionally, the end point of the monitoring period may be set by the time obtained by multiplying the count information of resource information by the unit time information used by the reader device to transmit one Message 2 after the start point (including the guard time between the transmission of Message 2 and the transmission of another Message 2). Alternatively, maximum time information may be utilized. The same formula as the monitoring window settings explained later may be applied to the method of setting the monitoring interval.

[0118] A method for performing a random access procedure may include the step of transmitting message 3 to a reader device through a resource scheduled by message 2 (S930).

[0119] When Message 2 is received, the ambient IoT terminal can transmit Message 3 to a reader device. Message 3 can be transmitted through a resource scheduled by Message 2. Message 3 may include unique terminal identification information rather than a random number.

[0120] If the transmission of Message 3 is successfully received by the reader device, the random access procedure may be considered successful. However, if Message 3 is not received by the reader device, it is determined that the random access procedure has not been successfully terminated. To this end, the ambient IoT terminal needs to determine whether the transmission of Message 3 was successful.

[0121] A method for performing a random access procedure may include the step of monitoring message 2 that is retransmitted from a monitoring window configured based on monitoring window configuration information (S940).

[0122] For example, the ambient IoT terminal must monitor whether message 2, which is retransmitted by the reader device, is received during a certain time interval after message 3 is transmitted. If message 2 is not received and the monitoring window is closed, message 3 is considered to have been successfully received by the reader device, and the random access procedure can be determined to have been successfully terminated.

[0123] In contrast, if Message 2 is received in the monitoring window, it may be determined that Message 3 was not received by the reader device. Therefore, the ambient IoT terminal may retransmit Message 3. Alternatively, the ambient IoT terminal may determine that the random access procedure has failed and try again starting from Message 1 in the next random access opportunity. Alternatively, the ambient IoT terminal may receive a trigger for random access from the reader device and proceed with the random access procedure again.

[0124] For this operation to work, the monitoring window needs to be configured correctly.

[0125] For example, monitoring window configuration information may be received by being included in a PRDCH (Physical Reader to Device Channel) for configuring one or more resource information. Alternatively, monitoring window configuration information may be received by being included in message 2.

[0126] The monitoring window setting information may include at least one of offset information for synchronizing the monitoring window start point, minimum time information for setting the monitoring window, maximum time information for setting the monitoring window, unit time information for transmitting message 2, and counting information.

[0127] For example, offset information may include information for synchronizing the starting point for monitoring Message 2 for multiple ambient IoT terminals performing a random access procedure within a slot. The offset information may be set based on various points, such as the end point of reception of Message 2, the end point of transmission of Message 3, the end point of the resource for receiving Message 2, and the end point of the transmission resource for transmitting Message 3. Additionally, it may be distinguished between cases where Message 2 is transmitted individually to a single ambient IoT terminal and cases where Message 2 for multiple ambient IoT terminals is included within a single PRDCH.

[0128] The minimum time information may be information for setting the time at which a monitoring window starts for the ambient IoT terminal to monitor the retransmission of Message 2. For example, the monitoring window may start at a time when the minimum time information has elapsed from the reference point.

[0129] Maximum time information may be information for setting the end point of a monitoring window. For example, a monitoring window can be set from a start point configured based on minimum time information to an end point configured using maximum time information.

[0130] Unit time information can be set as the time required for a reader device to transmit one message. For example, unit time information can be set as the combined time required for the reader device to transmit one message 2 and the guard time required to transmit message 2 for other ambient IoT terminals. That is, unit time information can be set as the time required to transmit one message 2. If the reader device transmits message 2 to multiple ambient IoT terminals through a single PRDCH, it can be set as the processing time for transmitting one message 2 within a single PRDCH.

[0131] Counting information may correspond to parameters for optimized dynamic window settings, such as the actual number of transmissions of Message 2 or Message 3 when setting a monitoring window. For example, the counting information may include any one of the total number of Message 2 transmitted by the reader device during the monitoring interval for receiving Message 2, the total number of Message 3 transmitted to the reader device, the number of one or more resource information, and instruction information set by the reader device.

[0132] The total count information of Message 2 refers to the total number of Message 2 transmitted by the reader device in response to Message 1, and may be counted by the ambient IoT terminal or explicitly indicated by the reader device. The total count information of Message 3 may refer to the total number of Message 3 transmitted to the reader device in the corresponding slot by one or more ambient IoT terminals that received Message 2, and may be counted by the ambient IoT terminal or explicitly indicated by the reader device. The count information of one or more resource information may be used to set a monitoring interval for receiving the initial Message 2, thereby allowing the monitoring interval for receiving the initial Message 2 to be set. The instruction information is the reader device explicitly indicating the count information as a value, and may be transmitted by the reader device using the aforementioned total count information of Message 2 or Message 3.

[0133] The ambient IoT terminal can perform monitoring operations by setting a monitoring window using the aforementioned information.

[0134] For example, the starting point of the monitoring window can be set after the minimum time information has elapsed from the reference point to which offset information is applied, corresponding to the transmission of Message 3 or the reception of Message 2. A reference point to which offset information is applied can be identified to ensure synchronization, such as when retransmission to multiple ambient IoT terminals is required. The starting point of the monitoring window can be set to the point to which the minimum time information has elapsed from the reference point. Here, the timing for applying offset information can be set in various ways depending on the reception of Message 2 or the transmission of Message 3.

[0135] As another example, the starting point of the monitoring window can be set by applying minimum time information at the time it is set corresponding to the transmission of Message 3 or the reception of Message 2. This can be understood as offset information being included in the minimum time information. That is, offset information may be indicated as being integrated into the minimum time information without being separated.

[0136] As another example, the end point of a monitoring window can be set by applying counting information to unit time information. For example, the end point of a monitoring window can be set by multiplying the unit time information associated with one message 2 by the count information confirmed according to the counting information. In this case, it can also be set by adding or subtracting an arbitrary number from the counting information.

[0137] As another example, the end point of the monitoring window can be set by extending the unit time information according to the counting information and applying the maximum time information. The unit time information is the time associated with one message 2 retransmission and can be extended by a certain multiple according to the counting information. In addition, the end point of the monitoring window can be determined by adding the maximum time information.

[0138] In addition to this, a monitoring window may be configured according to various embodiments described below.

[0139] Meanwhile, Message 2 may be received in a monitoring interval set based on the count information of one or more resource information. Since Message 2 or Message 3 cannot be used as counting information for the initial transmission of Message 2 rather than the retransmitted Message 2, the monitoring interval may be set using one or more resource information set for the transmission of Message 1 as counting information.

[0140] Through the above operations, the ambient IoT terminal can reduce unnecessary power loss by setting a monitoring window. In addition, it can prevent the continuous repetition of the message 2 monitoring operation after message 3 transmission, which may occur due to the ambiguity of the monitoring window.

[0141] FIG. 10 is a drawing for explaining the operation of a reader device according to one embodiment.

[0142] Referring to FIG. 10, a method for a reader device to control a random access procedure of an ambient IoT terminal may include the step of receiving a message 1 from an ambient IoT terminal through a transmission resource information selected from one or more resource information (S1010).

[0143] The reader device can receive Message 1 transmitted from an ambient IoT terminal to perform a random access procedure. Message 1 can be received through any transmission resource information selected from one or more resource information set by the reader device. Message 1 is received through the PDRCH (Physical Device to Reader Channel).

[0144] One or more resource information may be transmitted to an ambient IoT terminal through a connection opportunity resource setting message. One or more resources may consist of multiple resources distinguished by time and frequency axes. The ambient IoT terminal may randomly select a resource among the multiple resources to transmit Message 1.

[0145] Message 1 may include a random number. The random number is set to 16 bits and can be configured by randomly selecting it by an ambient IoT terminal. Through this, when multiple ambient IoT terminals transmit Message 1 using the same resource information, the reader device can distinguish the ambient IoT terminals.

[0146] A method for controlling a random access procedure may include the step of transmitting message 2 corresponding to message 1 to an ambient IoT terminal (S1020).

[0147] For example, a reader device may receive message 1, verify the random access procedure of the ambient IoT terminal, and transmit message 2 corresponding to message 1. Message 2 may include scheduling information for the ambient IoT terminal to schedule the transmission resources for message 3 to transmit message 3. Alternatively, message 2 may include a random number that was included in message 1. Through this, the ambient IoT terminal can confirm that message 2 corresponding to the transmission of message 1 has been received.

[0148] The reader device can transmit Message 2 during a monitoring period that the ambient IoT terminal monitors for receiving Message 2. The monitoring period may be determined based on the count information of one or more resource information. For example, the monitoring period may be set in correspondence with one or more resource information for transmitting Message 1. To this end, an index may be assigned and transmitted for each of the one or more resource information for transmitting Message 1. Alternatively, the monitoring period may start after a certain time based on the end point of the Message 1 transmission resource, and the end point may be determined based on the unit time information for transmitting Message 2 and the count information of one or more resource information. For example, the time when the transmission resource of Message 1 ends and a certain offset has elapsed may be set as the start point of the monitoring period. Additionally, the end point of the monitoring period may be set by the time obtained by multiplying the count information of resource information by the unit time information used by the reader device to transmit one Message 2 after the start point (including the guard time between transmitting Message 2 and another Message 2). Alternatively, maximum time information may be utilized.

[0149] A method for controlling a random access procedure may include the step of monitoring the reception of message 3 through a resource scheduled by message 2 (S1030).

[0150] When Message 2 is transmitted, the reader device can monitor whether Message 3 is received on a scheduling resource in order to receive Message 3 transmitted by the ambient IoT terminal. Message 3 may include unique terminal identification information rather than a random number.

[0151] If the reader device receives message 3 normally, the random access procedure may be considered successful. However, if message 3 is not received by the reader device, it is determined that the random access procedure was not successfully terminated. To this end, the ambient IoT terminal needs to determine whether the procedure was successful after the transmission of message 3.

[0152] A method for controlling a random access procedure may include the step of retransmitting message 2 in a monitoring window configured based on monitoring window configuration information when message 3 is not received (S1040).

[0153] For example, if the reader device determines that it has not received message 3, it can retransmit message 2 from the monitoring window to induce the ambient IoT terminal to retransmit message 3. This monitoring of message 3 and retransmission of message 2 can be repeated a set number of times according to certain criteria, and a counter value for this can be set and configured in the reader device and the ambient IoT terminal.

[0154] For example, monitoring window configuration information may be transmitted by being included in a PRDCH (Physical Reader to Device Channel) for configuring one or more resource information. Alternatively, monitoring window configuration information may be transmitted by being included in message 2.

[0155] The monitoring window setting information may include at least one of offset information for synchronizing the monitoring window start point, minimum time information for setting the monitoring window, maximum time information for setting the monitoring window, unit time information for transmitting message 2, and counting information.

[0156] For example, offset information may include information for synchronizing the starting point for monitoring Message 2 for multiple ambient IoT terminals performing a random access procedure within a slot. The offset information may be set based on various points, such as the end point of reception of Message 2, the end point of transmission of Message 3, the end point of the resource for receiving Message 2, and the end point of the transmission resource for transmitting Message 3. Additionally, it may be distinguished between cases where Message 2 is transmitted individually to a single ambient IoT terminal and cases where Message 2 for multiple ambient IoT terminals is included within a single PRDCH.

[0157] The minimum time information may be information for setting the time at which a monitoring window starts for the ambient IoT terminal to monitor the retransmission of Message 2. For example, the monitoring window may start at a time when the minimum time information has elapsed from the reference point.

[0158] Maximum time information may be information for setting the end point of a monitoring window. For example, a monitoring window can be set from a start point configured based on minimum time information to an end point configured using maximum time information.

[0159] Unit time information can be set as the time required for a reader device to transmit one message. For example, unit time information can be set as the combined time required for the reader device to transmit one message 2 and the guard time required to transmit message 2 for other ambient IoT terminals. That is, unit time information can be set as the time required to transmit one message 2. If the reader device transmits message 2 to multiple ambient IoT terminals through a single PRDCH, it can be set as the processing time for transmitting one message 2 within a single PRDCH.

[0160] Counting information may correspond to parameters for optimized dynamic window settings, such as the actual number of transmissions of Message 2 or Message 3 when setting a monitoring window. For example, the counting information may include any one of the total number of Message 2 transmitted by the reader device during the monitoring interval for receiving Message 2, the total number of Message 3 transmitted to the reader device, the number of one or more resource information, and instruction information set by the reader device.

[0161] The total count information of Message 2 refers to the total number of Message 2 transmitted by the reader device in response to Message 1, and may be counted by the ambient IoT terminal or explicitly indicated by the reader device. The total count information of Message 3 may refer to the total number of Message 3 transmitted to the reader device in the corresponding slot by one or more ambient IoT terminals that received Message 2, and may be counted by the ambient IoT terminal or explicitly indicated by the reader device. The count information of one or more resource information may be used to set a monitoring interval for receiving the initial Message 2, thereby allowing the monitoring interval for receiving the initial Message 2 to be set. The instruction information is the reader device explicitly indicating the count information as a value, and may be transmitted by the reader device using the aforementioned total count information of Message 2 or Message 3.

[0162] The ambient IoT terminal can perform monitoring operations by setting a monitoring window using the aforementioned information.

[0163] For example, the starting point of the monitoring window may be set after the minimum time information has elapsed from the reference point to which offset information is applied, corresponding to the transmission of Message 3 or the reception of Message 2. A reference point to which offset information is applied may be identified to ensure synchronization, such as when retransmission to multiple ambient IoT terminals is required. The starting point of the monitoring window may be set to the point to which the minimum time information has elapsed from the reference point. Here, the timing for applying offset information may be set in various ways depending on the transmission of Message 2 or the reception of Message 3.

[0164] As another example, the starting point of the monitoring window can be set by applying minimum time information at the time it is set corresponding to the transmission of Message 3 or the reception of Message 2. This can be understood as offset information being included in the minimum time information. That is, offset information may be indicated as being integrated into the minimum time information without being separated.

[0165] As another example, the end point of a monitoring window can be set by applying counting information to unit time information. For example, the end point of a monitoring window can be set by multiplying the unit time information associated with one message 2 by the count information confirmed according to the counting information. In this case, it can also be set by adding or subtracting an arbitrary number from the counting information.

[0166] As another example, the end point of the monitoring window can be set by extending the unit time information according to the counting information and applying the maximum time information. The unit time information is the time associated with one message 2 retransmission and can be extended by a certain multiple according to the counting information. In addition, the end point of the monitoring window can be determined by adding the maximum time information.

[0167] In addition to this, a monitoring window may be configured according to various embodiments described below.

[0168] Meanwhile, Message 2 may be transmitted in a monitoring interval set based on the count information of one or more resource information. Since the aforementioned Message 2 or Message 3 cannot be used as counting information for the initial transmitted Message 2 rather than the retransmitted Message 2, the monitoring interval may be set using one or more resource information set for the transmission of Message 1 as counting information.

[0169] Through the above operations, the ambient IoT terminal can reduce unnecessary power loss by setting a monitoring window. In addition, it can prevent the continuous repetition of the message 2 monitoring operation after message 3 transmission, which may occur due to the ambiguity of the monitoring window.

[0170] Below, various embodiments are described in more detail regarding the aforementioned operation. Any combination of embodiments described below can be performed through the operation steps of the aforementioned reader device and ambient IoT terminal.

[0171] Below, the period for monitoring message 2 transmitted by the reader device in response to the transmission of message 1 can be described as the first MSG2 monitoring period or the first monitoring duration. To distinguish this, the period for monitoring message 2 that is retransmitted after the transmission of message 3 can be described as the second MSG2 monitoring period or the second monitoring duration.

[0172]

[0173] The present disclosure allows an A-IoT device performing a random access procedure through any slot to successfully receive an MSG2 for an MSG1 it transmitted within a first MSG2 monitoring period and transmit an MSG3 through a resource indicated by the MSG2 (allocated or predefined), and to set a second MSG2 monitoring period for checking whether to retransmit or retry the RA for the MSG3 based on at least one of the following information.

[0174] - Number of MSG3s transmitted from multiple device(s); or

[0175] - Number of devices that successfully transmitted MSG1; or

[0176] - Number of devices that failed to successfully transmit MSG3; or

[0177] - Number of devices retransmitting MSG3; or

[0178] - Number of resources (AOs) allocated to transmit MSG3; or

[0179] - (If MSG2 is sent individually for MSG1) Number of MSG2s sent during the first MSG2 monitoring duration; or

[0180] - (where at least one MSG2 contains multiple MSG1s) Number of responses for MSG1s contained in MSG2(s) transmitted during the first MSG2 monitoring duration; or

[0181] - (If Early Indication (EI) for transmitted MSG2 is defined) Number of indicators indicating MSG2 to be transmitted during the first MSG2 monitoring duration.

[0182]

[0183] FIG. 11 is a diagram illustrating a message 2 monitoring operation according to one embodiment.

[0184] Referring to FIG. 11, an A-IoT terminal can receive a PRDCH containing random access (RA) resource information from a reader device (S1110). The RA resource information may include one or more resource information configured for the A-IoT terminal to transmit MSG1.

[0185] The A-IoT terminal can select any resource among the RA resource information and transmit MSG1 to the reader device. The A-IoT terminal receives MSG2 through a first monitoring duration corresponding to MSG1 (S1120).

[0186] When the A-IoT terminal receives MSG2, it can transmit MSG3 to the reader device through the resources indicated by MSG2 (S1130). For example, the A-IoT terminal receives MSG2, checks the scheduling information included in MSG2, and transmits MSG3 to the reader device.

[0187] The A-IoT terminal sets a second monitoring period based on the number of responses (n) received during the first monitoring period (S1140). Subsequently, the A-IoT terminal can perform a monitoring operation for message 2 during the set second monitoring period (S1140). If message 2 is retransmitted and received during the second monitoring period, the A-IoT terminal retransmits message 3. If message 2 is not received during the second monitoring period, the A-IoT terminal determines that the transmission of message 3 was successful. Accordingly, the random access procedure can be terminated as successful.

[0188] The second monitoring duration can be calculated using the parameter (n).

[0189] For example, the parameter (n) derived through the aforementioned count information, etc., can be implicitly calculated by the device based on one of the above information. Alternatively, the device that transmitted MSG3 may set the second MSG2 monitoring duration by explicitly including a value (n) corresponding to a parameter for setting the second / next MSG2 monitoring period within the PRDCH for the MSG2 transmitted during the first / previous monitoring duration. A device that receives the MSG2 corresponding to the MSG1 it transmitted sets the second MSG2 monitoring period after the MSG3 transmission based on the above derived / set information (n), and performs MSG2 monitoring based on this.

[0190] As another example, within the MSG2 transmitted during the first / previous monitoring duration, information on the second MSG2 monitoring duration(s) for one or multiple devices configured based on the information presented above may be explicitly included by the reader. This is a time interval [T after the PDRCH in which the starting time defined based on an arbitrary reference time and / or MSG3 is transmitted. D2R_min , T D2R_max This means that each time information of ] is calculated by the reader based on the above n value, and monitoring interval information can be explicitly transmitted to devices via PRDCH. If the UE operates as a reader, the UE can calculate the MSG2 monitoring interval based on the above information (n) and signal the calculated monitoring interval to the devices.

[0191] The n-based MSG2 monitoring interval setting method proposed in the present disclosure is also applicable to the first MSG2 monitoring interval. For the first monitoring interval, n can be defined as the total number of resources (AO) classified into t / f (time / frequency resources) through which MSG1 can be transmitted.

[0192] FIG. 12 is a diagram illustrating offset information for synchronizing a monitoring window start point according to one embodiment.

[0193] Referring to FIG. 12, the present disclosure may include time offset information for defining the start time of a second MSG2 monitoring time interval for monitoring MSG2 after MSG3 transmission within a PRDCH that triggers RA, includes resource information for RA, or transmits initial / first / previous MSG2.

[0194] This allows you to set a point in time after the offset as the reference time, using one of the following options, as the starting time of the second MSG2 monitoring interval.

[0195] ■ Option 1. Start from after the offset based on resource information for MSG3

[0196] ◆ Option 1-1. Based on MSG3 you sent

[0197] ◆ Option 1-2. Based on the last transmitted MSG3 among MSG3s transmitted by multiple devices

[0198] ■ Option 2. Starts after the offset based on the end of the MSG3 transmission.

[0199] ◆ Option 2-1. Based on MSG3 you sent

[0200] ◆ Option 2-2. Based on the last transmitted MSG3 among MSG3s transmitted by multiple devices

[0201] ■ Option 3. Start after the offset based on the end of the previous MSG2 transmission

[0202] ◆ Option 3-1. Based on the last transmitted MSG2 transmission end within the previous monitoring interval

[0203] ◆ Option 3-2. End-based of previous monitoring interval

[0204] Here, the offset information for options 1 and 2 is T D2R_min Replaced by (i.e., T D2R_min (Included in) set, or T D2R_min T with additional offset information not included in D2R_min It sets a time gap (i.e., offset) added later or earlier, which can be defined as a value for synchronizing the starting time with other devices. The former is T D2R_minThis can be applied when defined as one of the dynamic information set in the device as time resource information to indicate the next monitoring period. The latter is T D2R_min This can be applied when defined as the same / fixed value for each device type and / or service type. That is, in the former case, the reader considers the starting time of the monitoring interval for the devices and assigns T to each device considering the offset. D2R_min You can assign it, and the latter means setting an offset, which is additional time information, for the device to synchronize the starting time between the devices.

[0205] If the start time of the second MSG2 monitoring time interval is defined based on reference time and offset information, the A-IoT device(s) that transmitted MSG3 determine the monitoring time length for receiving MSG2 after transmitting MSG3 using offset and T D2R_min , T D2R_max In addition, it can be set based on the number of responses (n) to MSG1 transmitted before MSG3 transmission.

[0206] When a monitoring interval is defined commonly for multiple devices, MSG2 is transmitted via a single PRDCH for a single device; however, this can be divided into cases where a single monitoring interval is set for multiple MSG2s and cases where a single MSG2 is transmitted via a single PRDCH for multiple devices. In both cases, a single common MSG2 monitoring interval is established for the devices that transmitted MSG1, thereby enabling multiple devices to monitor the response message (MSG2) to the MSG1 they transmitted.

[0207] Below, each of the two cases is explained.

[0208] FIG. 13 is a diagram illustrating random access operation according to a monitoring window setting according to one embodiment.

[0209] Referring to Fig. 13, for example, when an A-IoT device transmits MSG2 to one device via one PRDCH, the time interval for monitoring the second MSG2 is:

[0210] - Number (n) derived based on the information presented above; and / or

[0211] - Time information (X) during which the Reader can transmit a series of responses (MSG2) to other A-IoT devices.

[0212] ■ For example, MSG2 transmission time (T msg2_max ) and the minimum time (T) between two consecutive MSG2(R2D) R2D_R2D_min ) information;

[0213] ■ Offset information to be added from the reference time.

[0214] Based on this, the second MSG2 monitoring time interval can be defined using the following formula.

[0215] [Mathematical Formula 1]

[0216] Second MSG2 monitoring duration = [T D2R_min , T D2R_max + (n-1) * X]

[0217] Here, X represents the minimum time required to transmit MSG2 to another device after one MSG2 transmission. For example, X is T msg2_max + T R2D_R2D_min It can be defined as, where T msg2_max can refer to the time it takes for the reader to actually transmit MSG2, which is sent as a response to MSG1 received from the device. T R2D_R2D_minmeans the minimum time interval that must be guaranteed between two consecutive MSG2s transmitted to different devices (after the transmission of MSG2, a consecutive MSG2 can be transmitted after that time, guard time).

[0218] The following is an example of the operation of the related device (A-IoT terminal) and reader.

[0219] [A-IoT device operation]

[0220] 1. Receive MSG0 via PRDCH that triggers RA. The message may include at least one of the following information.

[0221] A.T. D2R_min , T D2R_max ;

[0222] i. Time information related to processing for MSG2 after MSG1 / MSG3 transmission

[0223] B. X: T msg2_max , T R2D_R2D_min ;

[0224] i. T is the time required to transmit MSG2 to another device after transmitting MSG2. msg2_max , T R2D_R2D_min It can be expressed as the sum of.

[0225] C. Time / frequency resource information and total number of resources (y) capable of transmitting MSG1.

[0226] 2. Randomly select one of the configured competitive resources (AOs) and transmit MSG1 containing RN (Random Number) through the selected resource.

[0227] 3. Set the first MSG2 monitoring interval to monitor response messages for MSG1.

[0228] A. This can be achieved using the following formula based on the number of competing resources (y) for MSG1.

[0229] i. Set the value of n to y.

[0230] ii. [T D2R_min , T D2R_max + (n-1) * X]

[0231] 4. Receive MSG2 within the time interval set above.

[0232] 5. Transmit MSG3 through the resource directed by MSG2.

[0233] A. Set the value derived from one of the following methods to n.

[0234] i. Count MSG2 received within the above-mentioned previous monitoring interval; or

[0235] ii. Count MSG3 transmitted after receiving MSG2; or

[0236] iii. If there is a marker indicating the MSG2 to be transmitted, count the number of markers indicated by the marker; or

[0237] iv. If the value is transmitted by explicit signaling, set n to that value.

[0238] 6. Set the second MSG2 monitoring interval based on the n set above.

[0239] A. This can be done using the following equation based on n.

[0240] i. [T D2R_min , T D2R_max + (n-1) * X]

[0241] 7. MSG2 monitoring is performed during the time interval set above.

[0242] 8. If MSG2 is received, retransmit MSG3.

[0243] 9. If MSG2 is not received within the time interval, RA is considered successful at the end of the set time interval.

[0244] [Reader Action]

[0245] 1. Send MSG0 via PRDCH that triggers RA. The message may include at least one of the following information.

[0246] A.T. D2R_min , T D2R_max ;

[0247] i. Time information related to processing for MSG2 after MSG1 transmission

[0248] B. X: T msg2_max , T R2D_R2D_min ;

[0249] i. T is the time required to transmit MSG2 to another device after transmitting MSG2. msg2_max , T R2D_R2D_min It can be expressed as the sum of.

[0250] C. Time / frequency resource information and total number of resources (y) capable of transmitting MSG1.

[0251] 2. Receive MSG1(s) containing RN (Random Number) through the configured competition resource(s) (AO(s)).

[0252] 3. Set the first MSG2 monitoring interval to send a response message for the received MSG1(s).

[0253] A. This can be achieved using the following formula based on the number of competing resources (y) for MSG1.

[0254] i. Set the value of n to y.

[0255] ii. [T D2R_min , T D2R_max + (n-1) * X]

[0256] 4. Transmit MSG2 within the time interval set above.

[0257] 5. Receive MSG3 through the resource directed by MSG2.

[0258] A. Set the value derived from one of the following methods to n.

[0259] i. Count MSG2 transmitted within the above interval; or

[0260] ii. If there is a marker indicating the MSG2 to be transmitted, count the number of markers indicated by the marker.

[0261] iii. If the value is transmitted by explicit signaling, set n to that value.

[0262] 6. Set the second MSG2 transmission interval based on the n set above.

[0263] A. This can be done using the following equation based on n.

[0264] i. [T D2R_min , T D2R_max + (n-1) * X]

[0265] 7. Transmit MSG2 containing resource allocation information for MSG3 that failed to be received during the above-set time interval.

[0266]

[0267] As another example, we will also explain the case where a single MSG2 is transmitted over a single PRDCH for multiple devices.

[0268] FIG. 14 is a diagram illustrating random access operation according to a monitoring window setting according to another embodiment.

[0269] Referring to FIG. 14, specific details regarding the setting of the time interval during which the A-IoT device monitors the second MSG2 are described. In this embodiment, when the A-IoT device receives a single PRDCH for multiple devices, the time interval during which the second MSG2 is monitored is:

[0270] - Number (n) derived based on the information presented above; and / or

[0271] - When the Reader transmits a single MSG2 containing multiple responses for multiple devices, additional processing time information (X) required when one response for one device is added.

[0272] ■ For example, if response information for one or more MSG1s is transmitted within a single MSG2, the additional MSG2 transmission processing time (T) required for each increase in the number of responses rsp_max ).

[0273] ■ Offset information.

[0274] Based on this, the second MSG2 monitoring time interval can be defined using the following formula.

[0275] [Mathematical Formula 2]

[0276] Second MSG2 monitoring duration = [T D2R_min , T D2R_max + (n-1) * X]

[0277] Here, X represents the additional MSG2 transmission processing time required when the number of responses to MSG1 increases by one within one MSG2. For example, X is T rsp_max It can be defined as.

[0278] The following is an example of the operation of the device and reader according to the present embodiment.

[0279] [A-IoT device operation]

[0280] 1. Receive MSG0 via PRDCH that triggers RA. The message may include at least one of the following information.

[0281] A.T. D2R_min , T D2R_max ;

[0282] i. Time information related to processing for MSG2 after MSG1 / MSG3 transmission

[0283] B. X ;

[0284] i. Additional MSG2 transmission processing time required when the number of responses to MSG1 increases by one within a single MSG2

[0285] C. Time / frequency resource information and total number of resources (y) capable of transmitting MSG1.

[0286] 2. Randomly select one of the configured competitive resources (AOs) and transmit MSG1 containing RN (Random Number) through the selected resource.

[0287] 3. Set the first MSG2 monitoring interval to monitor response messages for MSG1.

[0288] A. This can be achieved using the following formula based on the number of competing resources (y) for MSG1.

[0289] i. Set the value of n to y.

[0290] ii. [T D2R_min , T D2R_max + (n-1) * X]

[0291] 4. Receive MSG2 within the time interval set above.

[0292] 5. Transmit MSG3 through the resource directed by MSG2.

[0293] A. Set the value derived from one of the following methods to n.

[0294] i. Count MSG2 received within the above-mentioned previous monitoring interval; or

[0295] ii. Count MSG3 transmitted after receiving MSG2; or

[0296] iii. If there is a marker indicating the MSG2 to be transmitted, count the number of markers indicated by the marker; or

[0297] iv. Count the number of responses for MSG1 included in the MSG2(s) transmitted during the first MSG2 monitoring period; or

[0298] v. If the value is transmitted via explicit signaling, set n to that value.

[0299] 6. Set the second MSG2 monitoring interval based on the n set above.

[0300] A. This can be done using the following equation based on n.

[0301] i. [T D2R_min , T D2R_max + (n-1) * X]

[0302] 7. MSG2 monitoring is performed during the time interval set above.

[0303] 8. If MSG2 is received, retransmit MSG3.

[0304] 9. If MSG2 is not received within the time interval, RA is considered successful at the end of the set time interval.

[0305] [Reader Action]

[0306] 1. Send MSG0 via PRDCH that triggers RA. The message may include at least one of the following information.

[0307] A.T. D2R_min , T D2R_max ;

[0308] i. Time information related to processing for MSG2 after MSG1 transmission

[0309] B. X: T msg2_max , T R2D_R2D_min ;

[0310] i. T is the time required to transmit MSG2 to another device after transmitting MSG2. msg2_max , T R2D_R2D_minIt can be expressed as the sum of.

[0311] C. Time / frequency resource information and total number of resources (y) capable of transmitting MSG1.

[0312] 2. Receive MSG1(s) containing RN (Random Number) through the configured competition resource(s) (AO(s)).

[0313] 3. Set the first MSG2 monitoring interval to send a response message for the received MSG1(s).

[0314] A. This can be achieved using the following formula based on the number of competing resources (y) for MSG1.

[0315] i. Set the value of n to y.

[0316] ii. [T D2R_min , T D2R_max + (n-1) * X]

[0317] 4. Transmit MSG2 within the time interval set above.

[0318] 5. Receive MSG3 through the resource directed by MSG2.

[0319] A. Set the value derived from one of the following methods to n.

[0320] i. Count MSG2 transmitted within the above interval; or

[0321] ii. If there is a marker indicating the MSG2 to be transmitted, count the number of markers indicated by the marker.

[0322] iii. If the value is transmitted by explicit signaling, set n to that value.

[0323] 6. Set the second MSG2 transmission interval based on the n set above.

[0324] A. This can be done using the following equation based on n.

[0325] i. [T D2R_min , T D2R_max + (n-1) * X]

[0326] 7. Transmit MSG2 containing resource allocation information for MSG3 that failed to be received during the above-set time interval.

[0327]

[0328] As explained above, the method for setting the MSG2 monitoring interval allows the device and the reader to set the optimal MSG2 monitoring duration by considering the number of MSG3s actually transmitted and received when the device and the reader transmit and receive MSG3s and set the MSG2 monitoring interval. Through this, the reader and the device can dynamically calculate the MSG2 monitoring duration based on the number of transmitted MSG3s without additional signaling, thereby minimizing the overall signaling overhead.

[0329] Below, the configuration of an ambient IoT terminal and a reader device capable of performing any of the aforementioned embodiments is described once again.

[0330] FIG. 15 is a diagram illustrating the configuration of an ambient IoT terminal according to one embodiment.

[0331] Referring to FIG. 15, an ambient IoT terminal (1500) performing a random access procedure may include a transmitter (1520) that transmits message 1 to a reader device through transmission resource information selected from one or more resource information, a receiver (1530) that receives message 2 corresponding to message 1 from the reader device, and a control unit (1510) that monitors message 2 retransmitted in a monitoring window based on monitoring window setting information after transmitting message 3 transmitted through a resource scheduled by message 2.

[0332] For example, the transmitter (1520) may transmit message 1 to a reader device to perform a random access procedure. Message 1 may be transmitted through any transmission resource information selected from one or more resource information set by the reader device. Message 1 is transmitted through the PDRCH (Physical Device to Reader Channel).

[0333] One or more resource information can be received through a connection opportunity resource setting message transmitted by a reader device. One or more resources may consist of multiple resources distinguished by time and frequency axes. The control unit (1510) may randomly select a resource among the multiple resources to transmit Message 1. Message 1 may include a random number. The random number is set to 16 bits and may be configured by randomly selecting it by an ambient IoT terminal.

[0334] For example, Message 2 corresponding to Message 1 may be delivered to an ambient IoT terminal. A reader device may receive Message 1, verify the random access procedure of the ambient IoT terminal, and transmit Message 2 corresponding to Message 1. Message 2 may include scheduling information for the ambient IoT terminal to schedule the transmission resources for Message 3 to transmit Message 3. Alternatively, Message 2 may include a random number that was included in Message 1.

[0335] The control unit (1510) can monitor whether message 2 is received in the monitoring section for the reception of message 2. The monitoring section may be determined based on the number information of one or more resource information. For example, the monitoring section may be set in correspondence with one or more resource information for the transmission of message 1. To this end, an index may be assigned and transmitted for each of one or more resource information for the transmission of message 1. Alternatively, the monitoring section may start after a certain time based on the end point of the message 1 transmission resource, and the end point may be determined based on unit time information for transmitting message 2 and the number information of one or more resource information. For example, the time when the transmission resource of message 1 ends and a certain offset has elapsed may be set as the start point of the monitoring section. In addition, the end point of the monitoring section may be set by the time obtained by multiplying the number information of resource information by the unit time information (including the guard time between the transmission of message 2 and the transmission of another message 2) used by the reader device to transmit one message 2 after the start point. Alternatively, maximum time information may be further utilized.

[0336] When message 2 is received, the transmitting unit (1520) can transmit message 3 to a reader device. Message 3 can be transmitted through a resource scheduled by message 2. Message 3 may include unique terminal identification information rather than a random number.

[0337] The control unit (1510) needs to determine whether the transmission of message 3 was successful.

[0338] For example, the control unit (1510) must monitor whether message 2, which is retransmitted by the reader device, is received during a certain time interval after message 3 is transmitted. If message 2 is not received and the monitoring window is closed, message 3 is considered to have been successfully received by the reader device, and the random access procedure can be determined to be successfully terminated.

[0339] In contrast, if message 2 is received in the monitoring window, it may be determined that message 3 was not received by the reader device. Therefore, the ambient IoT terminal may retransmit message 3. Alternatively, the control unit (1510) may determine that the random access procedure has failed and try again starting from message 1 in the next random access opportunity. Alternatively, the control unit (1510) may receive a trigger for random access from the reader device and proceed with the random access procedure again.

[0340] For this operation to work, the monitoring window needs to be configured correctly.

[0341] For example, monitoring window configuration information may be received by being included in a PRDCH (Physical Reader to Device Channel) for configuring one or more resource information. Alternatively, monitoring window configuration information may be received by being included in message 2.

[0342] The monitoring window setting information may include at least one of offset information for synchronizing the monitoring window start point, minimum time information for setting the monitoring window, maximum time information for setting the monitoring window, unit time information for transmitting message 2, and counting information.

[0343] For example, offset information may include information for synchronizing the starting point for monitoring Message 2 for multiple ambient IoT terminals performing a random access procedure within a slot. The offset information may be set based on various points, such as the end point of reception of Message 2, the end point of transmission of Message 3, the end point of the resource for receiving Message 2, and the end point of the transmission resource for transmitting Message 3. Additionally, it may be distinguished between cases where Message 2 is transmitted individually to a single ambient IoT terminal and cases where Message 2 for multiple ambient IoT terminals is included within a single PRDCH.

[0344] The minimum time information may be information for setting the time at which a monitoring window starts for the ambient IoT terminal to monitor the retransmission of Message 2. For example, the monitoring window may start at a time when the minimum time information has elapsed from the reference point.

[0345] Maximum time information may be information for setting the end point of a monitoring window. For example, a monitoring window can be set from a start point configured based on minimum time information to an end point configured using maximum time information.

[0346] Unit time information can be set as the time required for a reader device to transmit one message. For example, unit time information can be set as the combined time required for the reader device to transmit one message 2 and the guard time required to transmit message 2 for other ambient IoT terminals. That is, unit time information can be set as the time required to transmit one message 2. If the reader device transmits message 2 to multiple ambient IoT terminals through a single PRDCH, it can be set as the processing time for transmitting one message 2 within a single PRDCH.

[0347] Counting information may correspond to parameters for optimized dynamic window settings, such as the actual number of transmissions of Message 2 or Message 3 when setting a monitoring window. For example, the counting information may include any one of the total number of Message 2 transmitted by the reader device during the monitoring interval for receiving Message 2, the total number of Message 3 transmitted to the reader device, the number of one or more resource information, and instruction information set by the reader device.

[0348] The total count information of Message 2 refers to the total number of Message 2 transmitted by the reader device in response to Message 1, and may be counted by the ambient IoT terminal or explicitly indicated by the reader device. The total count information of Message 3 may refer to the total number of Message 3 transmitted to the reader device in the corresponding slot by one or more ambient IoT terminals that received Message 2, and may be counted by the ambient IoT terminal or explicitly indicated by the reader device. The count information of one or more resource information may be used to set a monitoring interval for receiving the initial Message 2, thereby allowing the monitoring interval for receiving the initial Message 2 to be set. The instruction information is the reader device explicitly indicating the count information as a value, and may be transmitted by the reader device using the aforementioned total count information of Message 2 or Message 3.

[0349] The control unit (1510) can perform monitoring operations by setting a monitoring window using the aforementioned information.

[0350] For example, the starting point of the monitoring window can be set after the minimum time information has elapsed from the reference point to which offset information is applied, corresponding to the transmission of Message 3 or the reception of Message 2. A reference point to which offset information is applied can be identified to ensure synchronization, such as when retransmission to multiple ambient IoT terminals is required. The starting point of the monitoring window can be set to the point to which the minimum time information has elapsed from the reference point. Here, the timing for applying offset information can be set in various ways depending on the reception of Message 2 or the transmission of Message 3.

[0351] As another example, the starting point of the monitoring window can be set by applying minimum time information at the time it is set corresponding to the transmission of Message 3 or the reception of Message 2. This can be understood as offset information being included in the minimum time information. That is, offset information may be indicated as being integrated into the minimum time information without being separated.

[0352] As another example, the end point of a monitoring window can be set by applying counting information to unit time information. For example, the end point of a monitoring window can be set by multiplying the unit time information associated with one message 2 by the count information confirmed according to the counting information. In this case, it can also be set by adding or subtracting an arbitrary number from the counting information.

[0353] As another example, the end point of the monitoring window can be set by extending the unit time information according to the counting information and applying the maximum time information. The unit time information is the time associated with one message 2 retransmission and can be extended by a certain multiple according to the counting information. In addition, the end point of the monitoring window can be determined by adding the maximum time information.

[0354] Meanwhile, Message 2 may be received in a monitoring interval set based on the count information of one or more resource information. Since Message 2 or Message 3 cannot be used as counting information for the initial transmission of Message 2 rather than the retransmitted Message 2, the monitoring interval may be set using one or more resource information set for the transmission of Message 1 as counting information.

[0355] In addition, the control unit (1510) controls the overall operation of the ambient IoT terminal (1500) according to the monitoring window settings and monitoring operations necessary to perform the above-described embodiment.

[0356] The transmitting unit (1520) and the receiving unit (1530) are used to transmit and receive signals, messages, and data necessary to perform the above-described embodiment with the reader device.

[0357] FIG. 16 is a drawing for explaining the configuration of a reader device according to one embodiment.

[0358] Referring to FIG. 16, a reader device (1600) controlling a random access procedure of an ambient IoT terminal may include a receiving unit (1630) that receives a message 1 from an ambient IoT terminal through a transmission resource information selected from one or more resource information, a transmitting unit (1620) that transmits a message 2 corresponding to message 1 to the ambient IoT terminal, and a control unit (1610) that monitors the reception of a message 3 through a resource scheduled by message 2.

[0359] If message 3 is not received, the transmitting unit (1620) can retransmit message 2 from the monitoring window configured based on the monitoring window configuration information.

[0360] The receiver (1630) can receive message 1 transmitted from an ambient IoT terminal to perform a random access procedure. Message 1 can be received through any transmission resource information selected from one or more resource information set by a reader device. Message 1 is received through a PDRCH (Physical Device to Reader Channel).

[0361] One or more resource information may be transmitted to an ambient IoT terminal through a connection opportunity resource setting message. One or more resources may consist of multiple resources distinguished by time and frequency axes. The ambient IoT terminal may randomly select a resource among the multiple resources to transmit Message 1. Message 1 may include a random number. The random number is set to 16 bits and may be configured by being randomly selected by the ambient IoT terminal.

[0362] For example, the control unit (1610) may receive message 1, check the random access procedure of the ambient IoT terminal, and control the transmission of message 2 corresponding to message 1. Message 2 may include scheduling information for the ambient IoT terminal to schedule the transmission resources of message 3 for transmitting message 3. Alternatively, message 2 may include a random number that was included in message 1.

[0363] The transmitting unit (1620) can transmit Message 2 in a monitoring section that the ambient IoT terminal monitors for receiving Message 2. The monitoring section may be determined based on the number information of one or more resource information. For example, the monitoring section may be set in correspondence with one or more resource information for transmitting Message 1. To this end, an index may be assigned and transmitted for each of one or more resource information for transmitting Message 1. Alternatively, the monitoring section may start after a certain time based on the end point of the Message 1 transmission resource, and the end point may be determined based on unit time information for transmitting Message 2 and the number information of one or more resource information. For example, the time when the transmission resource of Message 1 ends and a certain offset has elapsed may be set as the start point of the monitoring section. In addition, the time obtained by multiplying the number information of resource information by the unit time information (including the guard time between transmitting Message 2 and transmitting another Message 2) used by the reader device to transmit one Message 2 after the start point may be set as the end point of the monitoring section. Alternatively, maximum time information may be further utilized.

[0364] The control unit (1610) can monitor whether message 3 is received on a scheduling resource in order to receive message 3 transmitted by the ambient IoT terminal when message 2 is transmitted. Message 3 may include unique terminal identification information rather than a random number.

[0365] For example, if the control unit (1610) determines that message 3 has not been received, it can retransmit message 2 from the monitoring window to induce the ambient IoT terminal to retransmit message 3. Such monitoring of message 3 and retransmission of message 2 can be repeated a set number of times according to a certain standard, and a counter value for this can be set and configured in the reader device and the ambient IoT terminal.

[0366] Monitoring window configuration information may be transmitted by being included in a PRDCH (Physical Reader to Device Channel) for configuring one or more resource information. Alternatively, monitoring window configuration information may be transmitted by being included in message 2.

[0367] The monitoring window setting information may include at least one of offset information for synchronizing the monitoring window start point, minimum time information for setting the monitoring window, maximum time information for setting the monitoring window, unit time information for transmitting message 2, and counting information.

[0368] For example, offset information may include information for synchronizing the starting point for monitoring Message 2 for multiple ambient IoT terminals performing a random access procedure within a slot. The offset information may be set based on various points, such as the end point of reception of Message 2, the end point of transmission of Message 3, the end point of the resource for receiving Message 2, and the end point of the transmission resource for transmitting Message 3. Additionally, it may be distinguished between cases where Message 2 is transmitted individually to a single ambient IoT terminal and cases where Message 2 for multiple ambient IoT terminals is included within a single PRDCH.

[0369] The minimum time information may be information for setting the time at which a monitoring window starts for the ambient IoT terminal to monitor the retransmission of Message 2. For example, the monitoring window may start at a time when the minimum time information has elapsed from the reference point.

[0370] Maximum time information may be information for setting the end point of a monitoring window. For example, a monitoring window can be set from a start point configured based on minimum time information to an end point configured using maximum time information.

[0371] Unit time information can be set as the time required for a reader device to transmit one message. For example, unit time information can be set as the combined time required for the reader device to transmit one message 2 and the guard time required to transmit message 2 for other ambient IoT terminals. That is, unit time information can be set as the time required to transmit one message 2. If the reader device transmits message 2 to multiple ambient IoT terminals through a single PRDCH, it can be set as the processing time for transmitting one message 2 within a single PRDCH.

[0372] Counting information may correspond to parameters for optimized dynamic window settings, such as the actual number of transmissions of Message 2 or Message 3 when setting a monitoring window. For example, the counting information may include any one of the total number of Message 2 transmitted by the reader device during the monitoring interval for receiving Message 2, the total number of Message 3 transmitted to the reader device, the number of one or more resource information, and instruction information set by the reader device.

[0373] The total count information of Message 2 refers to the total number of Message 2 transmitted by the transmitting unit (1620) in correspondence with Message 1, and may be counted by the ambient IoT terminal or explicitly indicated by the reader device. The total count information of Message 3 refers to the total number of Message 3 transmitted to the reader device in the corresponding slot by one or more ambient IoT terminals that received Message 2, and may be counted by the ambient IoT terminal or explicitly indicated by the reader device. The count information of one or more resource information can be used to set a monitoring section for receiving the first Message 2, and through this, a monitoring section for receiving the first Message 2 can be set. The instruction information is the reader device explicitly indicating the count information as a value, and the reader device can transmit it using the total count information of the aforementioned Message 2 or Message 3, etc.

[0374] The ambient IoT terminal can perform monitoring operations by setting a monitoring window using the aforementioned information.

[0375] For example, the starting point of the monitoring window may be set after the minimum time information has elapsed from the reference point to which offset information is applied, corresponding to the transmission of Message 3 or the reception of Message 2. A reference point to which offset information is applied may be identified to ensure synchronization, such as when retransmission to multiple ambient IoT terminals is required. The starting point of the monitoring window may be set to the point to which the minimum time information has elapsed from the reference point. Here, the timing for applying offset information may be set in various ways depending on the transmission of Message 2 or the reception of Message 3.

[0376] As another example, the starting point of the monitoring window can be set by applying minimum time information at the time it is set corresponding to the transmission of Message 3 or the reception of Message 2. This can be understood as offset information being included in the minimum time information. That is, offset information may be indicated as being integrated into the minimum time information without being separated.

[0377] As another example, the end point of a monitoring window can be set by applying counting information to unit time information. For example, the end point of a monitoring window can be set by multiplying the unit time information associated with one message 2 by the count information confirmed according to the counting information. In this case, it can also be set by adding or subtracting an arbitrary number from the counting information.

[0378] As another example, the end point of the monitoring window can be set by extending the unit time information according to the counting information and applying the maximum time information. The unit time information is the time associated with one message 2 retransmission and can be extended by a certain multiple according to the counting information. In addition, the end point of the monitoring window can be determined by adding the maximum time information.

[0379] Meanwhile, Message 2 may be transmitted in a monitoring interval set based on the count information of one or more resource information. Since the aforementioned Message 2 or Message 3 cannot be used as counting information for the initial transmitted Message 2 rather than the retransmitted Message 2, the monitoring interval may be set using one or more resource information set for the transmission of Message 1 as counting information.

[0380] In addition to this, the control unit (1610) controls the overall operation of the reader device (1600) according to the monitoring window setting and random access operation control necessary to perform the above-described embodiment.

[0381] The transmitting unit (1620) and the receiving unit (1630) are used to transmit and receive signals, messages, and data necessary to perform the above-described embodiment with the ambient IoT terminal.

[0382] The aforementioned embodiments may be supported by standard documents disclosed in at least one of the wireless access systems IEEE 802, 3GPP, and 3GPP2. That is, steps, configurations, and parts in the embodiments that are not described to clearly reveal the technical concept may be supported by the aforementioned standard documents. Furthermore, all terms disclosed in this specification may be explained by the standard documents disclosed above.

[0383] The embodiments described above may be implemented through various means. For example, the embodiments may be implemented by hardware, firmware, software, or a combination thereof.

[0384] In the case of implementation by hardware, the method according to the embodiments may be implemented by one or more ASICs (Application Specific Integrated Circuits), DSPs (Digital Signal Processors), DSPDs (Digital Signal Processing Devices), PLDs (Programmable Logic Devices), FPGAs (Field Programmable Gate Arrays), processors, controllers, microcontrollers, or microprocessors.

[0385] In the case of implementation by firmware or software, the method according to the embodiments may be implemented in the form of a device, procedure, or function that performs the functions or operations described above. Software code may be stored in a memory unit and executed by a processor. The memory unit may be located inside or outside the processor and may exchange data with the processor by various means already known.

[0386] Additionally, terms such as "system," "processor," "controller," "component," "module," "interface," "model," or "unit" described above may generally refer to computer-related entities, hardware, combinations of hardware and software, software, or running software. For example, the aforementioned components may be, but are not limited to, processes driven by a processor, processors, controllers, control processors, objects, execution threads, programs, and / or computers. For example, both the application running on the controller or processor and the controller or processor may be components. One or more components may reside within a process and / or execution thread, and the components may be located on a single device (e.g., a system, a computing device, etc.) or distributed across two or more devices.

[0387] The foregoing description is merely an illustrative explanation of the technical concept of the present disclosure, and those skilled in the art to which the present disclosure pertains may make various modifications and variations within the scope of the essential characteristics of the technical concept. Furthermore, since these embodiments are intended to explain, not limit, the scope of the technical concept is not limited by these embodiments. The scope of protection of the present disclosure shall be interpreted by the claims below, and all technical concepts within an equivalent scope shall be interpreted as being included within the scope of rights of the present disclosure.

[0388]

[0389] CROSS-REFERENCE TO RELATED APPLICATION

[0390] This patent application claims priority pursuant to Section 119(a) of the U.S. Patent Act (35 USC § 119(a)) to Korean Patent Application No. 10-2024-0191025 filed on December 19, 2024, all of which are incorporated by reference into this patent application. Additionally, this patent application claims priority in countries other than the United States for the same reasons as above, all of which are incorporated by reference into this patent application.

Claims

1. A method for an ambient IoT terminal to perform a random access procedure, A step of transmitting Message 1 to the reader device through transmission resource information selected from one or more resource information; A step of receiving a message 2 corresponding to the above message 1 from the reader device; A step of transmitting message 3 to the reader device through a resource scheduled by the above message 2; and A method comprising the step of monitoring the message 2 retransmitted from a monitoring window configured based on monitoring window configuration information.

2. In Paragraph 1, The above monitoring window setting information is, A method of receiving included in a PRDCH (Physical Reader to Device Channel) for setting one or more of the above resource information.

3. In Paragraph 1, The above monitoring window setting information is, A method comprising at least one of offset information for synchronizing the starting point of the monitoring window, minimum time information for setting the monitoring window, maximum time information for setting the monitoring window, unit time information for transmitting message 2, and counting information.

4. In Paragraph 3, The above counting information is, A method comprising any one of the total number information of message 2 transmitted by the reader device in a monitoring section for receiving message 2, the total number information of message 3 transmitted to the reader device, the number information of one or more resource information, and instruction information set by the reader device.

5. In Paragraph 3, The starting point of the above monitoring window is, A method of setting the minimum time information after elapsed from the reference point to which the offset information is applied at the point to which the above message 3 is set in correspondence with the transmission of the above message 3 or the reception of the above message 2.

6. In Paragraph 3, The starting point of the above monitoring window is, A method of setting by applying the minimum time information at a time set in correspondence with the transmission of the above message 3 or the reception of the above message 2.

7. In Paragraph 3, The end point of the above monitoring window is, A method of setting by applying the above-mentioned counting information to the above-mentioned unit time information.

8. In Paragraph 7, The end point of the above monitoring window is, A method of setting by expanding the above unit time information according to the above counting information and applying the above maximum time information.

9. In Paragraph 1, The above message 2 is, A method of receiving in a monitoring section set based on the number information of one or more of the above resource information.

10. A method for a reader device to control a random access procedure of an ambient IoT terminal, A step of receiving Message 1 from an Ambient IoT terminal through transmission resource information selected from one or more resource information; A step of transmitting message 2 corresponding to message 1 to the ambient IoT terminal; A step of monitoring the reception of Message 3 through a resource scheduled by the above Message 2; and A method comprising the step of retransmitting message 2 in a monitoring window configured based on monitoring window configuration information when message 3 is not received.

11. In Paragraph 10, The above monitoring window setting information is, A method comprising at least one of offset information for synchronizing the starting point of the monitoring window, minimum time information for setting the monitoring window, maximum time information for setting the monitoring window, unit time information for transmitting message 2, and counting information.

12. In Paragraph 11, The above counting information is, A method comprising any one of the total number information of message 2 transmitted by the reader device, the total number information of message 3 transmitted to the reader device, the number information of one or more resource information, and instruction information set by the reader device in a monitoring section for the ambient IoT terminal to receive message 2.

13. In Paragraph 11, The starting point of the above monitoring window is, A method of setting the minimum time information after elapsed from the reference point to which the offset information is applied at the point to which the above message 3 is set in correspondence with the transmission of the above message 3 or the reception of the above message 2.

14. In Paragraph 11, The end point of the above monitoring window is, A method for setting the above unit processing time information according to the above counting information and applying the above maximum time information.

15. In an ambient IoT terminal performing a random access procedure, A transmitter that transmits Message 1 to the reader device through transmission resource information selected from one or more resource information; A receiver that receives a message 2 corresponding to the above message 1 from the reader device; and An ambient IoT terminal comprising a control unit that monitors message 2, which is retransmitted in a monitoring window configured based on monitoring window configuration information, after transmitting message 3 through a resource scheduled by message 2.

16. In Paragraph 15, The above monitoring window setting information is, An ambient IoT terminal comprising at least one of offset information for synchronizing the starting point of the monitoring window, minimum time information for setting the monitoring window, maximum time information for setting the monitoring window, unit time information for transmitting message 2, and counting information.

17. In Paragraph 16, The above counting information is, An ambient IoT terminal comprising any one of the total number information of message 2 transmitted by the reader device in a monitoring section for receiving the above message 2, the total number information of message 3 transmitted to the reader device, the number information of one or more resource information, and instruction information set by the reader device.

18. In Paragraph 16, The starting point of the above monitoring window is, An ambient IoT terminal configured by applying the minimum time information at a time configured in response to the transmission of the above message 3 or the reception of the above message 2.

19. In Paragraph 16, The end point of the above monitoring window is, An ambient IoT terminal configured by applying the counting information to the unit processing time information.

20. In Paragraph 19, The end point of the above monitoring window is, An ambient IoT terminal configured by extending the unit processing time information according to the counting information and applying the maximum time information.

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