Method and apparatus for retransmitting d2r segment in wireless communication system

Abstract

A method and an apparatus for retransmitting a D2R segment in a wireless communication system are provided. A device divides device-to-reader (D2R) data into a plurality of segments and transmits the plurality of segments through a first D2R resource In addition, the device receives transmission state information in response to the plurality of transmitted segments, and retransmits at least one segment among the plurality of transmitted segments through a second D2R resource on the basis of the received transmission state information.

Description

Method and device for retransmitting D2R segments in a wireless communication system

[0001] This specification relates to wireless communication applicable to 5G NR, 5G-Advanced, and 6G.

[0002] As the times change and more communication devices demand larger communication traffic, there is a demand for next-generation 5G systems, which are wireless broadband communication systems that are improved over existing LTE systems. In these next-generation 5G systems, referred to as NewRAT, communication scenarios are classified into Enhanced Mobile BroadBand (eMBB), Ultra-reliability and low-latency communication (URLLC), and Massive Machine-Type Communications (mMTC).

[0003] Here, eMBB is a next-generation mobile communication scenario characterized by High Spectrum Efficiency, High User Experienced Data Rate, and High Peak Data Rate; URLLC is a next-generation mobile communication scenario characterized by Ultra Reliable, Ultra Low Latency, and Ultra High Availability (e.g., V2X, Emergency Service, Remote Control); and mMTC is a next-generation mobile communication scenario characterized by Low Cost, Low Energy, Short Packet, and Massive Connectivity (e.g., IoT).

[0004] One disclosure of the present specification is to provide an efficient D2R message transmission method and apparatus for an ambient IoT device, i.e., a terminal, in a wireless communication system.

[0005] One embodiment of the present specification provides a wireless communication system in which a device divides Device-to-Reader (D2R) data into a plurality of segments and transmits the plurality of segments through a first D2R resource. Additionally, the device receives transmission status information in response to the transmitted plurality of segments and, based on the received transmission status information, provides a method for retransmitting at least one of the transmitted plurality of segments through a second D2R resource.

[0006] Additionally, one embodiment of the present specification provides a wireless communication system comprising at least one processor and at least one memory that stores instructions and is operablely electrically connected to at least one processor, wherein the operation performed based on the instruction being executed by at least one processor is: dividing D2R data into a plurality of segments and transmitting the plurality of segments through a first D2R resource. Additionally, the device provides a device that receives transmission status information in response to the transmitted plurality of segments and, based on the received transmission status information, retransmits at least one of the transmitted plurality of segments through a second D2R resource.

[0007] The device can receive a PRDCH (Physical Reader to Device Channel) message from a reader, and the PRDCH message may include information about the first D2R resource.

[0008] The above PRDCH message may further include partition instruction information, and the D2R data may be partitioned into the plurality of segments based on the partition instruction information.

[0009] The information regarding the first D2R resource may include information on a plurality of D2R transmission resources constituting the first D2R resource, and the D2R data may be divided into the plurality of segments based on the information of the plurality of D2R transmission resources.

[0010] Meanwhile, the above transmission status information may be composed of a bitmap.

[0011] Information regarding the second resource may be received along with the transmission status information, and the information regarding the second D2R resource may include information on at least one D2R transmission resource constituting the second resource, wherein the number of the at least one D2R transmission resource may correspond to the number of bits indicating transmission failure by the bitmap.

[0012] On the other hand, the plurality of segments may belong to a single segment group, and the retransmission of at least one segment may include the retransmission of all the plurality of segments belonging to the single segment group.

[0013] The above PRDCH message may further include time interval information for monitoring the transmission status information, and if the transmission status information is not received during the time interval according to the time interval information, the plurality of segments may be considered to have been successfully transmitted.

[0014] Information regarding the first D2R resource above may be based on expected D2R message size information transmitted from the core network or the device.

[0015] Additionally, the PRDCH message may further include at least one of information on the maximum number of bits per segment and information on the maximum number of bits per D2R transmission resource.

[0016] According to the disclosure of the present specification, latency occurring during the retransmission process can be reduced through efficient retransmission of D2R segments in a wireless communication system.

[0017] Figure 1 is a diagram illustrating a wireless communication system.

[0018] Figure 2 illustrates the structure of a wireless frame used in NR.

[0019] FIGS. 3a to 3c are exemplary diagrams illustrating an exemplary architecture for a wireless communication service.

[0020] Figure 4 illustrates the slot structure of an NR frame.

[0021] Figure 5 illustrates an example of a subframe type in NR.

[0022] Figure 6 illustrates the structure of a self-contained slot.

[0023] Figure 7 shows an example of a protocol between a reader and a tag.

[0024] FIGS. 8a through 8e show examples of connectivity topologies for ambient IoT networks and devices.

[0025] Figure 9 shows an example of an Access Stratum (AS) procedure between an ambient IoT device and a reader.

[0026] Figure 10 shows the wireless interface protocol stack between an ambient IoT device and a reader.

[0027] FIGS. 11a and 11b show examples of random access procedures.

[0028] FIGS. 12a to 12e show examples of R2D transmission corresponding to D2R.

[0029] Figure 13 shows an example of D2R segment transmission.

[0030] FIG. 14 is a drawing for explaining a first method according to one embodiment of the present specification.

[0031] FIG. 15 shows a drawing for explaining a second method in another embodiment of the present specification.

[0032] FIG. 16 is a flowchart illustrating a method of operation of a device according to one embodiment of the present specification.

[0033] FIGS. 17 and 18 illustrate procedures between a reader and a device according to one embodiment of the present specification.

[0034] FIGS. 19 to 20 illustrate procedures between a reader and a device according to another embodiment of the present specification.

[0035] FIG. 21 is a flowchart illustrating a method of operation of a device according to another embodiment of the present specification.

[0036] FIG. 22 shows an apparatus according to one embodiment of the present specification.

[0037] FIG. 23 is a block diagram showing the configuration of a terminal according to one embodiment of the present specification.

[0038] FIG. 24 shows a block diagram of a processor in which the disclosure of the present specification is implemented.

[0039] FIG. 25 is a block diagram showing in detail the transceiver of the first device shown in FIG. 22 or the transceiver of the device shown in FIG. 23.

[0040] It should be noted that technical terms used in this specification are used merely to describe specific embodiments and are not intended to limit the content of this specification. Furthermore, unless specifically defined otherwise in this specification, technical terms used in this specification should be interpreted in the sense generally understood by those skilled in the art to which this disclosure pertains, and should not be interpreted in an overly broad or overly narrow sense. Additionally, if a technical term used in this specification is an incorrect technical term that fails to accurately express the content and concept of this specification, it should be understood as being replaced by a technical term that can be correctly understood by those skilled in the art. Moreover, general terms used in this specification should be interpreted according to their prior definitions or the context, and should not be interpreted in an overly narrow sense.

[0041] Additionally, singular expressions used in this specification include plural expressions unless the context clearly indicates otherwise. In this application, terms such as "composed of" or "have" should not be interpreted as necessarily including all of the various components or steps described in the specification, and should be interpreted as meaning that some of the components or steps may be omitted or additional components or steps may be included.

[0042] Additionally, terms including ordinal numbers, such as first, second, etc., used herein may be used to describe various components, but said components shall not be limited by said terms. Such terms are used solely for the purpose of distinguishing one component from another. For example, without departing from the scope of the rights, the first component may be named the second component, and similarly, the second component may be named the first component.

[0043] When it is stated that a component is connected to or coupled with another component, it may be directly connected to or coupled with that other component, or there may be other components in between. On the other hand, when it is stated that a component is directly connected to or directly coupled with another component, it should be understood that there are no other components in between.

[0044] Hereinafter, embodiments will be described in detail with reference to the attached drawings. Identical or similar components regardless of drawing symbols are assigned the same reference number, and redundant descriptions thereof will be omitted. Furthermore, in describing the contents of this specification, if it is determined that a detailed description of related prior art may obscure the gist of this specification, such detailed description will be omitted. Additionally, it should be noted that the attached drawings are intended only to facilitate understanding of the contents and concepts of this specification, and should not be interpreted as limiting the contents and concepts of this specification. The contents and concepts of this specification should be interpreted as extending to all modifications, equivalents, and substitutions in addition to the attached drawings.

[0045] In this specification, “A or B” may mean “only A,” “only B,” or “both A and B.” Alternatively, in this specification, “A or B” may be interpreted as “A and / or B.” For example, in this specification, “A, B or C” may mean “only A,” “only B,” “only C,” or “any combination of A, B and C.”

[0046] As used herein, a slash ( / ) or a comma may mean “and / or.” For example, “A / B” may mean “A and / or B.” Accordingly, “A / B” may mean “only A,” “only B,” or “both A and B.” For example, “A, B, C” may mean “A, B or C.”

[0047] In this specification, “at least one of A and B” may mean “only A,” “only B,” or “both A and B.” Additionally, in this specification, the expressions “at least one of A or B” or “at least one of A and / or B” may be interpreted as synonymous with “at least one of A and B.”

[0048] Additionally, in this specification, “at least one of A, B and C” may mean “only A,” “only B,” “only C,” or “any combination of A, B and C.” Additionally, “at least one of A, B or C” or “at least one of A, B and / or C” may mean “at least one of A, B and C.”

[0049] Additionally, parentheses used in this specification may mean “for example.” Specifically, where indicated as “Control Information (PDCCH),” “PDCCH (Physical Downlink Control Channel)” may be proposed as an example of “Control Information.” In other words, “Control Information” in this specification is not limited to “PDCCH,” and “PDDCH” may be proposed as an example of “Control Information.” Furthermore, even when indicated as “Control Information (i.e., PDCCH),” “PDCCH” may be proposed as an example of “Control Information.”

[0050] Technical features described individually within a single drawing in this specification may be implemented individually or simultaneously.

[0051] In the attached drawings, User Equipment (UE) is illustrated as an example, but the illustrated UE may also be referred to by terms such as Terminal or Mobile Equipment (ME). Furthermore, the UE may be a portable device such as a laptop, mobile phone, PDA, smartphone, multimedia device, etc., or a non-portable device such as a PC or vehicle-mounted device.

[0052] In the following, UE is used as an example of a wireless communication-capable device (e.g., wireless communication device, wireless device, or wireless apparatus). The operations performed by the UE may be performed by any wireless communication-capable device. A wireless communication-capable device may also be referred to as a wireless communication device, wireless device, or wireless apparatus.

[0053] The term "base station" as used below generally refers to a fixed station that communicates with wireless devices, and can be used as a comprehensive term including eNodeB (evolved-NodeB), eNB (evolved-NodeB), BTS (Base Transceiver System), Access Point, gNB (Next generation NodeB), RRH (remote radio head), TP (transmission point), RP (reception point), relay, etc.

[0054] This specification describes embodiments using LTE systems, LTE-A systems and NR systems, but these embodiments may be applied to any communication system corresponding to the above definitions.

[0055] Wireless Communication System

[0056] Building on the success of LTE (long term evolution) / LTE-Advanced (LTE-A) for 4th generation mobile communication, commercialization and subsequent research for the next generation, namely 5th generation (so-called 5G) mobile communication, are also continuing.

[0057] Fifth-generation mobile communication, as defined by the International Telecommunication Union (ITU), refers to providing data transmission speeds of up to 20 Gbps and a perceived transmission speed of at least 100 Mbps anywhere. It is officially referred to as 'IMT-2020'.

[0058] The ITU presents three major usage scenarios, such as eMBB (enhanced Mobile BroadBand), mMTC (massive Machine Type Communication), and URLLC (Ultra Reliable and Low Latency Communications).

[0059] URLLC concerns use scenarios requiring high reliability and low latency. For example, services such as autonomous driving, factory automation, and augmented reality require high reliability and low latency (e.g., latency of 1ms or less). Currently, the latency of 4G (LTE) is statistically 21-43ms (best 10%) and 33-75ms (median). This is insufficient to support services requiring latency of 1ms or less. Next, eMBB use scenarios concern use scenarios requiring mobile ultra-broadband.

[0060] In other words, 5th generation mobile communication systems support higher capacity than current 4G LTE, increase the density of mobile broadband users, and can support D2D (Device to Device), high stability, and MTC (Machine type communication). 5G research and development also aims for lower latency and lower battery consumption than 4G mobile communication systems to better implement the Internet of Things. New radio access technology (New RAT or NR) may be proposed for such 5G mobile communication.

[0061] The NR frequency band can be defined by two types of frequency ranges (FR1, FR2). The numerical values ​​of the frequency ranges may change; for example, the two types of frequency ranges (FR1, FR2) may be as shown in Table 1 below. For convenience of explanation, among the frequency ranges used in the NR system, FR1 may mean the “sub 6GHz range” and FR2 may mean the “above 6GHz range” and may be referred to as millimeter wave (mmW).

[0062] Frequency Range designationCorresponding frequency rangeSubcarrier SpacingFR1410MHz - 7125MHz15, 30, 60kHzFR224250MHz - 52600MHz60, 120, 240kHz

[0063] The numerical values ​​of the frequency range of the NR system may change. For example, FR1 may include a band of 410 MHz to 7125 MHz as shown in Table 1. That is, FR1 may include a frequency band of 6 GHz (or 5850, 5900, 5925 MHz, etc.) or higher. For example, the frequency band of 6 GHz (or 5850, 5900, 5925 MHz, etc.) or higher included within FR1 may include an unlicensed band. The unlicensed band may be used for various purposes, for example, for communication for vehicles (e.g., autonomous driving).

[0064] Meanwhile, 3GPP-based communication standards define downlink physical channels corresponding to resource elements that carry information originating from upper layers, and downlink physical signals corresponding to resource elements used by the physical layer but not carrying information originating from upper layers. For example, physical downlink shared channel (PDSCH), physical broadcast channel (PBCH), physical multicast channel (PMCH), physical control format indicator channel (PCFICH), physical downlink control channel (PDCCH), and physical hybrid ARQ indicator channel (PHICH) are defined as downlink physical channels, and reference signals and synchronization signals are defined as downlink physical signals. A reference signal (RS), also referred to as a pilot, refers to a signal of a specific waveform that is known to both the gNB and the UE. For example, cell-specific RS, UE-specific RS (UE-RS), positioning RS (PRS), and channel state information RS (CSI-RS) are defined as downlink reference signals. The 3GPP LTE / LTE-A standard defines uplink physical channels corresponding to resource elements that carry information originating from upper layers, and uplink physical signals corresponding to resource elements used by the physical layer but that do not carry information originating from upper layers.For example, the physical uplink shared channel (PUSCH), physical uplink control channel (PUCCH), and physical random access channel (PRACH) are defined as uplink physical channels, and the demodulation reference signal (DMRS) for uplink control / data signals and the sounding reference signal (SRS) used for uplink channel measurement are defined.

[0065] In this specification, PDCCH (Physical Downlink Control Channel) / PCFICH (Physical Control Format Indicator Channel) / PHICH (Physical Hybrid automatic retransmit request Indicator Channel) / PDSCH (Physical Downlink Shared Channel) each refers to a set of time-frequency resources or a set of resource elements carrying DCI (Downlink Control Information) / CFI (Control Format Indicator) / downlink ACK / NACK (ACKnowlegement / Negative ACK) / downlink data. Additionally, PUCCH (Physical Uplink Control Channel) / PUSCH (Physical Uplink Shared Channel) / PRACH (Physical Random Access Channel) each refers to a set of time-frequency resources or a set of resource elements carrying UCI (Uplink Control Information) / uplink data / random access signals.

[0066] Figure 1 is a diagram illustrating a wireless communication system.

[0067] As can be seen with reference to FIG. 1, the wireless communication system includes at least one base station (BS). The BS is divided into a gNodeB (or gNB) (20a) and an eNodeB (or eNB) (20b). The gNB (20a) supports 5th generation mobile communication. The eNB (20b) supports 4th generation mobile communication, i.e., LTE (Long Term Evolution).

[0068] Each base station (20a and 20b) provides communication services for a specific geographical area (generally called a cell) (20-1, 20-2, 20-3). A cell can be further divided into multiple areas (called sectors).

[0069] User Equipment (UE) typically belongs to a single cell, and the cell to which the UE belongs is called the serving cell. The base station that provides communication services to the serving cell is called the serving base station (serving BS). Since the wireless communication system is a cellular system, there exists another cell adjacent to the serving cell. The other cell adjacent to the serving cell is called the neighbor cell. The base station that provides communication services to the neighbor cell is called the neighbor base station (neighbor BS). The serving cell and neighbor cells are determined relatively to the UE.

[0070] In the following, the downlink refers to communication from the base station (20) to the UE (10), and the uplink refers to communication from the UE (10) to the base station (20). In the downlink, the transmitter may be part of the base station (20) and the receiver may be part of the UE (10). In the uplink, the transmitter may be part of the UE (10) and the receiver may be part of the base station (20).

[0071] Meanwhile, wireless communication systems can be broadly classified into Frequency Division Duplex (FDD) and Time Division Duplex (TDD) methods. In the FDD method, uplink and downlink transmissions occupy different frequency bands. In the TDD method, uplink and downlink transmissions occupy the same frequency band and occur at different times. The channel response in the TDD method is practically reciprocal. This means that the downlink channel response and the uplink channel response are nearly identical within a given frequency range. Therefore, in a wireless communication system based on TDD, there is an advantage in that the downlink channel response can be derived from the uplink channel response. In the TDD method, since the entire frequency band is time-divided for uplink and downlink transmissions, downlink transmission by the base station and uplink transmission by the UE cannot be performed simultaneously. In a TDD system where uplink and downlink transmissions are separated by subframes, uplink and downlink transmissions are performed in different subframes.

[0072] Figure 2 illustrates the structure of a wireless frame used in NR.

[0073] In NR, uplink and downlink transmissions consist of frames. A radio frame has a length of 10 ms and is defined as two 5 ms half-frames (HF). A half-frame is defined as five 1 ms subframes (SF). A subframe is divided into one or more slots, and the number of slots within a subframe depends on the subcarrier spacing (SCS). Each slot contains 12 or 14 OFDM(A) symbols depending on the cyclic prefix (CP). When a standard CP is used, each slot contains 14 symbols. When an extended CP is used, each slot contains 12 symbols. Here, the symbols may include OFDM symbols (or CP-OFDM symbols) or SC-FDMA symbols (or DFT-s-OFDM symbols).

[0074] Support for various numerologies

[0075] In NR systems, as wireless communication technology develops, multiple numerologies may be provided to the terminal. For example, when the SCS is 15 kHz, it supports a wide area in traditional cellular bands; when the SCS is 30 kHz / 60 kHz, it supports dense-urban, lower latency, and wider carrier bandwidth; and when the SCS is 60 kHz or higher, it supports a bandwidth greater than 24.25 GHz to overcome phase noise.

[0076] The above numerology can be defined by the cycle prefix (CP) length and the subcarrier spacing (SCS). A single cell can provide multiple numerologies to the terminal. When the index of the numerology is denoted by μ, each subcarrier spacing and the corresponding CP length may be as shown in the table below.

[0077] μ△f=2 μ 15 [kHz]CP015General 130General 260General, Extended 3120General 4240General 5480General 6960General

[0078] For a standard CP, when the numerology index is denoted by μ, the number of OFDM symbols per slot (N slot symb ), number of slots per frame (N frame,μ slot ) And, the number of slots per subframe (N subframe,μ slot ) is as shown in the table below.

[0079] μ△f=2 μ 15 [kHz]N slot symb N frame,μ slot N subframe,μ slot 015141011301420226014404312014808424014160165480143203269601464064

[0080] For extended CP, when the numerology index is denoted by μ, the number of OFDM symbols per slot (N slot symb ), number of slots per frame (N frame,μ slot ) And, the number of slots per subframe (N subframe,μ slot ) is as shown in the table below.

[0081] μSCS (15*2 u )N slot symb N frame,μ slot N subframe,μslot 260KHz (u=2)12404

[0082] In an NR system, the OFDM(A) numerology (e.g., SCS, CP length, etc.) can be configured differently among multiple cells that are merged into a single terminal. Accordingly, the (absolute time) interval of a time resource (e.g., SF, slot, or TTI) (collectively referred to as TU (Time Unit) for convenience) composed of the same number of symbols can be configured differently among the merged cells.

[0083] FIGS. 3a to 3c are exemplary diagrams illustrating exemplary architectures for wireless communication services.

[0084] Referring to Fig. 3a, the UE is connected to an LTE / LTE-A based cell and an NR based cell in a DC (dual connectivity) manner.

[0085] The above NR-based cell is connected to the core network for existing 4th generation mobile communication, namely the EPC (Evolved Packet Core).

[0086] Referring to Fig. 3b, unlike Fig. 3a, the LTE / LTE-A based cell is connected to a core network for 5th generation mobile communication, that is, a 5G core network.

[0087] A service method based on the architecture as illustrated in Figures 3a and 3b above is called NSA (non-standalone).

[0088] Referring to Fig. 3c, the UE is connected only to NR-based cells. A service method based on this architecture is called SA (standalone).

[0089] Meanwhile, in the above NR, it may be considered that reception from the base station utilizes a downlink subframe, and transmission to the base station utilizes an uplink subframe. This method can be applied to paired spectra and unpaired spectra. A paired spectrum means that it includes two carrier spectra for downlink and uplink operations. For example, in a paired spectrum, one carrier may include a downlink band and an uplink band that are paired with each other.

[0090] Figure 4 illustrates the slot structure of an NR frame.

[0091] A slot contains multiple symbols in the time domain. For example, in the case of a standard CP, one slot contains 14 symbols, whereas in the case of an extended CP, one slot contains 12 symbols. A carrier contains multiple subcarriers in the frequency domain. A Resource Block (RB) is defined as multiple (e.g., 12) consecutive subcarriers in the frequency domain. A Bandwidth Part (BWP) is defined as multiple consecutive (physical, P)RBs in the frequency domain and can correspond to a single numerology (e.g., SCS, CP length, etc.). A terminal may be configured with up to N (e.g., 4) BWPs in both the downlink and uplink. Downlink or uplink transmission is performed through an active BWP, and at a given time, only one of the BWPs configured for the terminal may be active. In the resource grid, each element is referred to as a Resource Element (RE), and a single complex symbol may be mapped to it.

[0092] Figure 5 illustrates an example of a subframe type in NR.

[0093] The transmission time interval (TTI) illustrated in Fig. 5 can be referred to as a subframe or slot for NR (or new RAT). The subframe (or slot) of Fig. 5 can be used in the TDD system of NR (or new RAT) to minimize data transmission delay. As illustrated in Fig. 5, the subframe (or slot) contains 14 symbols. The symbols at the beginning of the subframe (or slot) can be used for the downlink (DL) control channel, and the symbols at the end of the subframe (or slot) can be used for the uplink (UL) control channel. The remaining symbols can be used for DL ​​data transmission or UL data transmission. According to this subframe (or slot) structure, downlink transmission and uplink transmission can proceed sequentially within a single subframe (or slot). Thus, downlink data can be received within the subframe (or slot), and uplink acknowledgments (ACK / NACK) can be transmitted within that subframe (or slot).

[0094] The structure of such a subframe (or slot) can be called a self-contained subframe (or slot).

[0095] Specifically, the first N symbols within the slot are used to transmit a DL control channel (hereinafter referred to as the DL control area), and the last M symbols within the slot may be used to transmit a UL control channel (hereinafter referred to as the UL control area). N and M are each integers greater than or equal to 0. A resource area (hereinafter referred to as the data area) located between the DL control area and the UL control area may be used for DL ​​data transmission or for UL data transmission. For example, a physical downlink control channel (PDCCH) may be transmitted in the DL control area, and a physical downlink shared channel (PDSCH) may be transmitted in the DL data area. A physical uplink control channel (PUCCH) may be transmitted in the UL control area, and a physical uplink shared channel (PUSCH) may be transmitted in the UL data area.

[0096] Using such a subframe (or slot) structure has the advantage of reducing the time required to retransmit data that has received errors, thereby minimizing the waiting time for final data transmission. In such a self-contained subframe (or slot) structure, a time gap may be required during the transition from transmit mode to receive mode or from receive mode to transmit mode. To this end, some OFDM symbols during the transition from DL to UL in the subframe structure may be set as a Guard Period (GP).

[0097] Figure 6 illustrates the structure of a self-contained slot.

[0098] In an NR system, a frame is characterized by a self-complete structure in which a DL control channel, DL or UL data, a UL control channel, etc., can all be included within a single slot. For example, the first N symbols within the slot are used to transmit a DL control channel (hereinafter referred to as the DL control area), and the last M symbols within the slot may be used to transmit a UL control channel (hereinafter referred to as the UL control area). N and M are each integers greater than or equal to 0. The resource area (hereinafter referred to as the data area) located between the DL control area and the UL control area may be used for transmitting DL data or for transmitting UL data. As an example, the following configuration can be considered. Each section is listed in chronological order.

[0099] 1. DL only configuration

[0100] 2. UL only configuration

[0101] 3. Mixed UL-DL Configuration

[0102] - DL Area + GP (Guard Period) + UL Control Area

[0103] - DL Control Area + GP + UL Area

[0104] DL Area: (i) DL Data Area, (ii) DL Control Area + DL Data Area

[0105] UL Area: (i) UL Data Area, (ii) UL Data Area + UL Control Area

[0106] PDCCH can be transmitted in the DL control area, and PDSCH can be transmitted in the DL data area. PUCCH can be transmitted in the UL control area, and PUSCH can be transmitted in the UL data area. In PDCCH, DCI (Downlink Control Information), such as DL data scheduling information and UL data scheduling information, can be transmitted. In PUCCH, UCI (Uplink Control Information), such as ACK / NACK (Positive Acknowledgement / Negative Acknowledgement) information for DL ​​data, CSI (Channel State Information) information, and SR (Scheduling Request), can be transmitted. GP provides a time gap during the process in which the base station and the terminal switch from transmit mode to receive mode or from receive mode to transmit mode. Within a subframe, some symbols at the point of transition from DL to UL can be set as GP.

[0107] Meanwhile, IoT technology has garnered significant attention in wireless communication over the past few years. IoT technology has evolved to enable a greater number of interconnected objects, thereby improving industrial productivity and quality of life. Examples of this include NB-IoT (Narrowband Internet of Things) and eMTC (enhanced Machine-Type Communication) technologies defined by 3GPP. However, to build a more effective IoT ecosystem, improvements are needed in various aspects, such as the size, form factor, price, complexity, power consumption, and coverage of IoT devices.

[0108] Radio Frequency Identification (RFID) is a representative technology service of the IoT. The advantages of RFID include very low complexity and the fact that RFID tags have a very small form factor. However, RFID supports a very narrow coverage area with a reading distance of only a few meters, is labor-intensive due to handheld scanning, and requires high deployment costs due to the installation costs of RFID portals / gates. Therefore, RFID has limitations in supporting seamless service and coverage in large-scale networks.

[0109] To meet these requirements, 3GPP has been conducting studies on ambient IoT technology since Release 18. Ambient IoT devices have a lower form factor compared to conventional IoT devices and support energy harvesting based on battery-less or minimal energy storage capability, allowing them to operate without charging or with minimal power charging. In addition, research is being conducted to support wide coverage based on higher power efficiency and to enable the utilization of RF signals supported by existing networks.

[0110] In addition, 3GPP is conducting research on protocol stacks and signaling procedures that take into account the low form factor and battery capacity characteristics of ambient IoT devices, such as less than 1 μW or less than several hundred μW. In particular, definitions are being made for the paging message functionality, which is the first message transmitted by a reader or base station to an ambient IoT device for wireless access of the ambient IoT device, and the random access procedure of the ambient IoT device.

[0111] For convenience of explanation, in this specification, an ambient IoT device may be referred to as an ambient IoT terminal, an IoT device, an IoT terminal, a device, or a terminal.

[0112] Figure 7 shows an example of a protocol between a reader and a tag.

[0113] RFID technology, which is the foundation of ambient IoT technology, is defined in the document "EPC Radio-Frequency Identity Protocols Generation-2 UHF RFID". This document defines the protocol between the reader and the tag and adopts a slotted-ALOHA-based random access procedure.

[0114] Referring to Fig. 7, the reader has three main actions: select, inventory, and access. The select action is an action in which the reader selects one or more tag populations, and it consists of 'select' and 'challenge' commands. At this time, the tags enter a ready state. The select command is a mandatory action, and the challenge command is an optional action. The select command allows the reader to select a tag population based on user-defined criteria. The inventory action involves the reader identifying / detecting each tag and generating a unique Random Number (RN) based on commands / responses with each tag to prepare for access. The access action involves the reader performing mutual communication with each tag to carry out procedures such as read / write / authenticate.

[0115] A tag can exist in various states during communication with a reader. First, the tag may enter a "ready" state, where it becomes operational upon receiving power from the reader, and subsequently an "arbitrate" state to prevent collisions when multiple tags exist simultaneously. Additionally, it may enter a "reply" state, where it transmits temporary identifiers or similar information in response to the reader's query commands, and an "acknowledge" state, where the reader recognizes and selects a specific tag. Furthermore, the tag may enter an "open" state, where a session with the reader is open allowing for the transmission and reception of additional commands, and a "secured" state, when authentication or encryption procedures are completed. Meanwhile, if the tag receives a kill command, it transitions to a "killed" state and may not respond to any subsequent reader commands.

[0116] FIGS. 8a through 8e show examples of connectivity topologies for ambient IoT networks and devices.

[0117] Connectivity topologies such as those shown in FIGS. 8a to 8e can be defined for ambient IoT networks and devices.

[0118] Referring to FIG. 8a, the ambient IoT device communicates directly and bidirectionally with a base station (BS). Communication between the base station and the ambient IoT device includes ambient IoT data and / or signaling. In the topology of FIG. 7a, the BS transmitted to the ambient IoT device may be different from the BS received from the ambient IoT device.

[0119] Referring to FIG. 8b, the ambient IoT device communicates bidirectionally with an intermediate node between the device and the base station. In the topology of FIG. 8b, the intermediate node can be an ambient IoT-enabled relay, an IAB (Integrated Access Backhaul) node, a UE, a repeater, etc. The intermediate node transmits ambient IoT data and / or signaling between the BS and the ambient IoT device.

[0120] Referring to FIG. 8c, the ambient IoT device transmits data / signaling to a base station and receives data / signaling from an assisting node. Alternatively, as shown in FIG. 8d, the ambient IoT device receives data / signaling from a base station and transmits data / signaling to an assisting node. The assisting node in the topology of FIG. 8c to FIG. 8d can be an ambient IoT-enabled relay, IAB, UE, repeater, etc.

[0121] Referring to FIG. 8e, the ambient IoT device communicates bidirectionally with the UE. Communication between the UE and the ambient IoT device includes the transmission of ambient IoT data and / or signaling.

[0122] Figure 9 shows an example of an Access Stratum (AS) procedure between an ambient IoT device and a reader.

[0123] Referring to FIG. 9, the overall Access Stratum (AS) procedure between an ambient IoT (A-IoT) device and a reader is described below.

[0124] Step A: A-IoT Paging (S901)

[0125] The reader transmits an A-IoT paging message indicating the device requiring a response in response to the service request. Here, the A-IoT paging message can be used interchangeably with the initial trigger message.

[0126] Step B: D2R (Device-to-Reader) data transfer (S902~S903)

[0127] An A-IoT device triggered by paging can transmit a device identifier (ID) to the reader, either by performing an A-IoT random access procedure or without such procedure. Subsequently, D2R data is transmitted to the reader.

[0128] Step C1: R2D (Reader-to-Device) data transfer (S904)

[0129] Optionally, the reader can transmit data including commands, etc. to the device.

[0130] Step C2: D2R data transmission (S905)

[0131] Optionally, the device can transmit response data to the above command to the reader.

[0132] These procedures can support the following A-IoT use cases:

[0133] Inventory-only: Can be supported through a procedure consisting of Step A and Step B.

[0134] Inventory and command: This can be supported through a procedure including steps A, B, C1, and C2. Here, this does not mean that the A-IoT paging message includes both inventory and command simultaneously, nor does it mean that the reader receives both inventory and command simultaneously from the upper layer.

[0135] Command-only: Basically, this can be supported through a procedure consisting of steps A, B, C1, and C2, and the following alternative procedures may also be considered.

[0136] Step A: The reader can send an A-IoT paging message containing a command to a device to instruct the device to process the command and respond.

[0137] Step C2: The device transmits device ID or response data for the command; this process may be performed through an A-IoT random access procedure or without such procedure.

[0138] Meanwhile, 3GPP classifies ambient IoT terminals into three types as shown in Table 5 below.

[0139] DeviceTypeEnergyStoragePeak PowerConsumptionAmplificationUL Independent Signal GenerationUL Tx MethodPassiveDevice 1Yes≤ 1 μWNoNoBackscattering from external CWDevice 2aYes≤ a few hundred μWYes (DL and / or UL)NoBackscattering from external CWActiveDevice 2bYes≤ a few hundred μWYes (DL and / or UL)NoGenerated internally

[0140] In Table 5, the difference between passive and active is the presence or absence of an independent signal generation function and hardware within the ambient IoT device. If there is no independent signal generation function for uplink (UL) signal transmission of the ambient IoT device, it is defined as passive, and if there is an independent signal generation function, it is defined as active.

[0141] Device 1 has a maximum power consumption of 1 μW or less and lacks independent signal generation and amplification capabilities. Additionally, the uplink of the ambient IoT device is transmitted via backscattering of the external carrier wave signal. Device 2a has a maximum power consumption of several hundred μW or less, does not support independent signal generation, but supports UL / DL amplification. Additionally, the UL is transmitted via backscattering of the external carrier wave signal. Device 2b has a maximum power consumption of several hundred μW or less and supports independent signal generation and UL / DL amplification capabilities. Additionally, the UL is transmitted through signal generation within the device.

[0142] Meanwhile, the common feature of Devices 1, 2a, and 2b discussed by 3GPP to date is that they are equipped with energy storage devices inside the ambient IoT devices. However, ambient IoT devices may have energy storage of limited capacity depending on the topology and deployment scenario. Here, limited energy storage may refer to a storage device composed of small-sized capacitors. In order to support seamless communication between the reader and the ambient IoT device, protocols and signaling to support energy harvesting need to be defined, but detailed operations have not yet been defined.

[0143] Meanwhile, discussions on ambient IoT topologies are underway at 3GPP, and the topologies of FIGS. 8a to 8d described above are applicable to the present invention, and in particular, it is preferable to apply the topologies of FIGS. 8a to 8b.

[0144] In addition, 3GPP decided to support paging messages at the Access Stratum (AS) layer between ambient IoT devices and readers (e.g., base stations), but since existing paging messages are difficult to support, it decided to define new A-IoT paging messages. The purpose of A-IoT paging is to have ambient IoT device(s) identify and select / determine a radio resource, and then send a Device-to-Reader (D2R) response message to the reader.

[0145] To identify A-IoT device(s), types of identifier information in the form shown in Table 6 are being discussed for paging messages. (Table 6. Types of A-IoT device identifier information in paging messages)

[0146] Cases Information Type Recipient Case 1 Single A-IoT device ID A single A-IoT Device Case 2 Group ID Multiple A-IoT device(s) mapped to a Group ID Case 3 No ID-related information All A-IoT device(s) receiving A-IoT paging messages Case 4 Multiple A-IoT device IDs Multiple A-IoT device IDs

[0147] In addition, regarding the method of selecting / determining radio resources for D2R transmission (e.g., Message 1) of ambient IoT devices, how (implicit / explicit / configured / preconfigured) or through which (dedicated / shared) resources D2R transmission is performed will be discussed later.

[0148] Figure 10 shows the wireless interface protocol stack between an ambient IoT device and a reader.

[0149] Referring to FIG. 10, the Access Stratum (AS) protocol stack for an ambient IoT (A-IoT) wireless interface includes an A-IoT Medium Access Control (MAC) layer and an A-IoT Physical (PHY) layer. Control information and data of the AS layer are processed by the A-IoT MAC layer and the A-IoT PHY layer. In an A-IoT wireless interface, the control plane and the user plane are not distinguished.

[0150] FIGS. 11a and 11b show examples of random access procedures.

[0151] Discussions are underway at 3GPP regarding random access procedures for ambient IoT device(s). The Slotted-ALOHA random access procedure has been adopted as the standard, and Content-Based Random Access (CBRA) and Content-Free Random Access (CFRA) for a single device, a group of devices, or all devices are set to be defined. Additionally, CBRA-based 4-step, 3-step, and 2-step procedures, as well as CFRA procedures, are also under discussion.

[0152] FIGS. 11a and 11b respectively show examples of CBRA-based 2-step and 3-step (or 4-step) Random Access (RA) procedures. A-IoT devices must select one of a 2-step CBRA, a 3-step CBRA, or a CFRA, and the information for making the selection can be made explicitly through an A-IoT paging message or implicitly through specific information within the A-IoT paging message.

[0153] Referring to FIG. 11a, the reader transmits Message 0 (Message 0, MSG0) to the device (S1101a). Here, MSG0 may be an A-IoT paging message, which may include candidate radio resource information required for the device to perform D2R transmission (Message 1). Additionally, device ID (identity) information may be included in MSG0 and transmitted.

[0154] Subsequently, the device randomly selects a resource, i.e., an access occasion, from among candidate radio resources consisting of a time / frequency / code sequence (S1102a). The device transmits Message 1 (MSG1) to the reader (1103a), where MSG1 may include at least one of a device ID, upper layer data, and a random ID.

[0155] The reader transmits an R2D message, i.e., Message 2 (Message 2, MSG2), to the device, including some of the information received from MSG1 (S1104a). The random ID (information) included in MSG1 may be included in MSG2 and transmitted.

[0156] Referring to FIG. 11b, the reader transmits Message 0 (Message 0, MSG0) to the device (S1101b). Here, MSG0 may be an A-IoT paging message, which may include candidate radio resource information required for the device to perform D2R transmission (Message 1). Additionally, device ID (identity) information may be included in MSG0 and transmitted.

[0157] Subsequently, the device randomly selects a resource, i.e., an access occasion, from among candidate radio resources consisting of a time / frequency / code sequence (S1102b). The device transmits Message 1 (MSG1) to the reader (1103b), where MSG1 may include at least a random ID.

[0158] The reader transmits an R2D message, i.e., Message 2 (Message 2, MSG2), to the device, including some of the information received from MSG1 (S1104b). The random ID (information) included in MSG1 may be included in MSG2 and transmitted. Contention resolution may be performed by exchanging the random ID (information) through MSG1 and MSG2. This random ID information and dedicated resource information may be included in MSG2 and transmitted to the device. The dedicated resource information may be for transmitting Message 3 (Message 3, MSG3).

[0159] Subsequently, the terminal transmits MSG3 to the reader (S1105b), which may include at least one of a device ID and upper layer data. After transmitting MSG3, the terminal may receive Message 4 (MSG4) from the reader (S1106b). Here, MSG4 may be defined as a message for handling MSG3 transmission failure or the reader's MSG3 reception failure, and may not necessarily be a message that requires transmission and reception. If MSG4 transmission and reception are required, the reader (e.g., base station) may transmit MSG4 to the device(s), which can be assumed to be a 4-step RA procedure. In addition to MSG4, additional message transmission and reception may occur between the A-IoT device and the reader (e.g., base station) as needed. However, to date, it has not been determined what type of random access procedure the A-IoT device(s) will determine in the RA (random access) procedure, and what information is required in the paging and R2D messages transmitted by the reader (e.g., base station) for the RA determination.

[0160] FIGS. 12a to 12e show examples of R2D transmission corresponding to D2R.

[0161] 3GPP is also discussing communication methods based on FDM(A), TDM(A), and CDM(A) in A-IoT systems. In wireless resource allocation, they are discussing support measures for communication based on frequency / time / code sequence. Figures 12a to 12e illustrate various examples of D2R and R2D transmission methods based on FDM(A) and TDM(A).

[0162] FIGS. 12a through 12e assume a procedure in which A-IoT devices perform random access (RA) in different steps, such as 2-step or 3-step. Examples according to the corresponding R2D transmission method are shown when the A-IoT device transmits a D2R message using Frequency Division Multiple Access (FDMA) or Time Division Multiple Access (TDMA).

[0163] FIG. 12a illustrates the transmission of an FDMA-based D2R message (MSG1) and the transmission of an R2D message (MSG2) corresponding to the D2R message transmitted by multiple A-IoT devices. FIG. 12b illustrates the transmission of an FDMA-based D2R message (MSG1) and the sequential transmission of an R2D message (MSG2) corresponding to the D2R message transmitted by a single A-IoT device. That is, FIG. 12b represents a case where a reader that receives a D2R message transmitted by an A-IoT device transmits the corresponding R2D message individually and sequentially for each D2R message. FIG. 12c is similar to FIG. 11b, but differs in that, from the reader's perspective, the transmission of the R2D message (MSG2) is triggered for Device 2, which receives the D2R message first, and the D2R message (MSG3) transmitted by Device 2 is executed first. Subsequently, it represents a case where the R2D message corresponding to the D2R message transmitted by Device 1 is transmitted.

[0164] FIG. 12d illustrates the transmission of a TDMA-based D2R message (MSG1) and the transmission of an R2D message (MSG2) corresponding to the D2R message transmitted by multiple A-IoT devices. FIG. 12e illustrates a case where an A-IoT device transmits a D2R message (MSG1) based on TDMA, and a reader transmits an R2D message (MSG2) via a different frequency than that of the A-IoT device. In this case, the reader can transmit a corresponding R2D message for each D2R message transmitted by the A-IoT device.

[0165] Meanwhile, regarding the timing relationship between an A-IoT device and a reader (e.g., a base station) in terms of D2R and R2D message transmission, reception, and processing time, it can be defined as follows.

[0166] T R2D_minFrom the reader's perspective, this may refer to the minimum time required from the transmission of an R2D message to the transmission of the corresponding D2R message. (T R2D_min : Minimum time between a R2D transmission and the corresponding D2R transmission following it.)

[0167] T D2R_min From the device's perspective, this may refer to the minimum time required from the transmission of a D2R message to the transmission of the corresponding R2D message. (T D2R_min : Minimum time between a D2R transmission and the corresponding R2D transmission following it.)

[0168] T D2R_max From the device's perspective, this may refer to the maximum time required from the transmission of the D2R message to the transmission of the corresponding R2D message. The transmission timing of the R2D message (MSG2) corresponding to the D2R message (MSG1) is [T D2R_min , T D2R_max It can be defined that it must take place within the ] time interval. (T D2R_max : Maximum time between the D2R transmission and the corresponding R2D transmission following it, so that the R2D transmission timing is expected to be within [T D2R_min , T D2R_max ], when a R2D transmission in response to a D2R transmission is expected for A-IoT Msg2 response to A-IoT Msg1 for the A-IoT device.)

[0169] Additionally, the reader can continuously transmit two different R2D transmissions to a single device, in which case the minimum time between R2D transmissions is T R2D_R2D_min It can be defined as. (T R2D_R2D_min : Minimum time between two different consecutive R2D transmissions to the same A-IoT device.)

[0170] In addition, the same device can perform two different D2R transmissions consecutively, and the minimum time between each D2R transmission is T D2R_D2R_min It can be defined as. (T D2R_D2R_min : Minimum time between two different consecutive D2R transmissions from the same A-IoT device.)

[0171] Additionally, regarding the time interval between the R2D transmission and the corresponding subsequent D2R transmission, the following two options can be considered.

[0172] Option 1: Maximum time T between an R2D transmission and the corresponding subsequent D2R transmission R2D_max By defining, the device [T R2D_min , T R2D_max Perform D2R transmission within the ] interval. (Option 1: Define a maximum time T R2D_max between a R2D transmission and the corresponding D2R transmission following it, so that the device transmits D2R transmission within [T R2D_min , T R2D_max ].)

[0173] Option 2: Timing T of the corresponding D2R transmission following the R2D transmissionR2D is determined based on control information included in the R2D transmission, where T R2D ≥ T R2D_min am. (Option 2: The corresponding D2R transmission timing T R2D Following a R2D transmission is determined based on the control information in the R2D transmission, where T R2D ≥T R2D_min .

[0174] Meanwhile, regarding the utilization of expected D2R message size information, 3GPP is discussing methods for readers to obtain this information. The expected D2R message size refers to the estimated size of the D2R data that a device will transmit to the reader. There are two methods for the reader to obtain this information: Option 1, which involves obtaining it from the Core Network (CN), and Option 2, which involves obtaining it from the device via a simple message size indication. If the CN cannot provide this information, the system may operate under Option 2; in this case, due to Access Stratum (AS) layer overhead issues, the expected D2R message size information may be provided with a limited granularity. Operating under Option 1 has the advantage of partially resolving the overhead issues associated with Option 2. The advantages and disadvantages of each option will be discussed in detail during the Work Item (WI) phase.

[0175] Furthermore, discussions regarding segmentation between devices and readers are ongoing at 3GPP. One of the reasons for introducing segmentation is to resolve the problem where D2R messages cannot be transmitted using only the dedicated resources allocated by the reader, as the D2R data size exceeds the amount of dedicated D2R resources available. In this case, a resource allocation method of an appropriate size and segmentation are required for D2R transmission.

[0176] During the transmission of D2R segment(s), a device may fail to transmit at least one segment. If a device fails to transmit D2R segment(s), a D2R segment(s) retransmission mechanism is required to resolve the issue. However, to date, no discussion or agreement has been reached regarding a segment(s) retransmission mechanism, and it has been agreed not to support information regarding sequence numbers, segment numbers, and the total number of segments for segmentation. Furthermore, Ambient IoT does not support RLC (Radio Link Control)-like repetition functions. Therefore, the present invention aims to provide a method for retransmitting segments following a D2R segment transmission failure.

[0177] Specifically, the present invention aims to provide a segmentation-based D2R data transmission and retransmission method for a device and a corresponding procedure in an ambient IoT system that supports only the PHY and MAC layers. Through the retransmission method according to the present invention, a reader can provide a dedicated resource for retransmission to a device along with a retransmission instruction due to failure to receive D2R segment(s), and accordingly, the device can transmit D2R data more efficiently based on the provided information.

[0178] Additionally, the reader may configure radio resource information divided into time / frequency domains based on the expected D2R message size obtained from the CN (Core Network) or the device, and provide it to the device. The device transmits D2R segment(s) to the reader using the obtained radio resource information. If at least one D2R segment fails to be transmitted, the reader may instruct the device to retransmit the D2R segment(s) or to retransmit the D2R segment(s) that failed to be received.

[0179] Figure 13 shows an example of D2R segment transmission.

[0180] A use case may be considered in which A-IoT data, specifically D2R data, is transmitted only when triggered by a CN request. In this case, the reader may receive the expected D2R message size in advance from the CN or the device. Accordingly, the reader can allocate the resources required for D2R transmission based on the expected D2R message size received from the CN or the device. Referring to Fig. 13, the resource information can be transmitted to the device via the PRDCH (Physical Reader to Device Channel). The device determines the segmentation of the D2R data triggered by the CN request, classifies the D2R data into i segments, and transmits these segments to the reader through dedicated resources distinguished by time and frequency. (Fig. 13 illustrates the case where i=3.) Here, each segment consists of a data field and a segment field. Additionally, the segment field of the last segment may include an indicator that indicates that the segment is the last. Among the i segments transmitted by the device, j (j-het) segments may fail to be transmitted. In this case, the device may need to retransmit the failed D2R segments. However, since a mechanism for D2R segment retransmission is currently not defined, a solution that takes this into account is required.

[0181] Therefore, the present invention proposes two methods for D2R segment transmission and retransmission. The two methods are described in detail below.

[0182] Scheme 1: Bitmap-based ACK / NACK

[0183] FIG. 14 is a drawing for explaining a first method according to one embodiment of the present specification.

[0184] The first method involves the reader constructing a bitmap considering the reception status of the D2R segment and transmitting the corresponding bitmap information to the device to instruct retransmission. The reader can expect the reception of each segment through the dedicated D2R resources allocated to the device. If the reader has allocated i dedicated D2R resources, it can expect the reception of j (j=i) segments corresponding to said D2R resources. However, even if the reader has allocated i dedicated D2R resources, the device may have fewer than i dedicated D2R resources j (j <i)개 만을 사용하여 세그먼트를 전송할 수 있다. 이 때, 리더는 디바이스가 전송한 j개의 세그먼트의 수신 성공 및 수신 실패를 비트맵 형태로 구성할 수 있다.

[0185] For example, a bitmap indicating the reception success and reception failure of j segments through i D2R dedicated resources separated into different time- / frequency- / code- domains is [D i , D i-1 It can be constructed as [ , ..., D0]. Here, D i The field is a bit indicating the success or failure status of receiving the i-th segment through the i-th D2R dedicated resource (D2R dedicated resource or dedicated D2R resource). D ii represents the i-th D2R dedicated resource, distinguished by time, frequency, and code domains. D0 indicates the success or failure of receiving a segment through the first resource in the D2R dedicated resource set, and D1 indicates the success or failure of receiving a segment through the second resource in the D2R dedicated resource set. If the reader succeeds in receiving a segment through the first D2R resource, the bit corresponding to D0 is set to 1, and if the segment is not received, the bit corresponding to D0 can be set to 0. Conversely, if the reader succeeds in receiving a segment, D0 can be set to 0, and if the segment is not received, D0 can be set to 1. The total length of the bitmap can be composed of an i-bit or j-bit length based on the number of D2R dedicated resources (i) allocated by the reader to the device or the number of D2R segments (j) transmitted by the device. Therefore, if the reader successfully receives all segments through i D2R dedicated resources, [D i , D i-1 [, ..., D0] can be configured as a bitmap in the form [1, 1, ..., 1], and if all segments fail to be received, a bitmap in the form [0, 0, ..., 0] can be configured. In this case, the length of the bitmap can be i-bit length, which is the number of i D2R dedicated resources allocated by the reader, or j-bit length, which is the number of j segments transmitted by the device. FIG. 14 shows an example of bitmap configuration based on the above description. Although the number of octets is shown as an example of 4, it can be configured as 1 octet depending on the bitmap length.

[0186] The reader can transmit bitmap information and additional D2R dedicated resource information to the device via R2D / D2R control information, PHY control information, or MAC CE (Control Element). Additional D2R dedicated resources may be allocated based on the number of bits in the bitmap indicating segment reception failure. For example, if the number of 0 bits indicating D2R segment reception failure is k, the number of additional D2R dedicated resources allocated may be k.

[0187] A device that receives bitmap and additional D2R-dedicated resource information can perform retransmission using additional D2R-dedicated resources for segments that failed to be transmitted in D2R among the segments it sent. If there is no information regarding additional D2R-dedicated resources, segment retransmission can be performed using previously transmitted D2R-dedicated resources.

[0188] If a device has transmitted segments using all i allocated D2R dedicated resources but there is still additional D2R data to be transmitted, it may request additional D2R dedicated resources from a reader. The request message for additional D2R dedicated resources may include request information of size 1 bit, or information on the number of bits representing the size of the remaining D2R data to be transmitted. Upon receiving the request message for additional D2R dedicated resources, the reader may allocate additional D2R dedicated resources by considering the information within the received message.

[0189] Scheme 2: Group ACK / NACK

[0190] FIG. 15 shows a drawing for explaining a second method in another embodiment of the present specification.

[0191] A second approach is for the leader to instruct the device to explicitly retransmit D2R segments by considering the success or failure of segment reception by group. A group ACK means that the leader has successfully received all segments through the D2R dedicated resources within the group. Additionally, a group NACK means that the leader has failed to receive at least one segment through the D2R dedicated resources within the group, which may instruct the device to retransmit all segments transmitted to the D2R dedicated resources within that group.

[0192] When a reader allocates i D2R dedicated resources, it can expect to receive j (j-het) segments from a device. In this case, the reader may define the i D2R dedicated resources into n groups, and may provide the group information to the device along with the D2R dedicated resource information. If the reader fails to receive a segment through at least one of the D2R dedicated resources within a group, it may instruct retransmission for all segments within that group.

[0193] If the reader organizes a total of i D2R dedicated resources into a single group, and fails to receive at least one segment through the D2R dedicated resources within the group, the reader may explicitly instruct the device to retransmit the entire segment. In this case, since the failure to receive even a single segment instructs the retransmission of all D2R data segments, the reader does not need to provide the device with separate group information for each D2R dedicated resource in advance. FIG. 15 is an example in which i D2R dedicated resources are organized into a single group as described above. Here, D2R i represents the i-th D2R dedicated resource. That is, the reader can instruct the device to retransmit the entire segment if it fails to receive at least one segment.

[0194] As another example, if the reader configures a total of 10 D2R dedicated resources into 2 groups, segment reception can be expected through 5 D2R dedicated resources per group. In this case, if at least one segment fails to be received in only the first group, the reader may instruct the device to retransmit all segments within the first group. The retransmission instruction message may include a 1-bit NACK, retransmission instruction information, information on the group requiring retransmission, and / or information on the D2R dedicated resources that failed to receive the segment.

[0195] A device that receives a message instructing retransmission or a message containing group NACK information may retransmit the entire segment. Alternatively, if the message contains group information, the device may retransmit all segments within the group containing the segment that failed to transmit.

[0196] In addition, regarding the segment retransmission trigger point, if the device receives D2R-specific resource allocation information again via PRDCH (Physical Reader to Device Channel) from the reader during an arbitrary time interval, it is determined that the segment transmission failed and the entire segment can be retransmitted. Conversely, if the device does not receive any message from the reader during an arbitrary time interval, it can be determined that the D2R segment was successfully transmitted. The aforementioned arbitrary time interval is [T considering the processing time of the A-IoT device D2R_min , T D2R_max It can be a ] value, or it can follow the setting information received in advance from the reader.

[0197] Below, based on the two methods described above, the step-by-step operations between the device and the reader are described in detail from the perspective of procedures. The steps described below may be composed of specific combinations, which include the possibility that at least one step may be omitted.

[0198] Step 1: [Device] Segmentation Determination

[0199] Based on the expected D2R data size (i.e., expected D2R message size) information obtained from the device or core network (CN), the reader configures a dedicated allocated resource divided into time / frequency / code areas and transmits it to the device via PRDCH.

[0200] Explicitly, indicator information to instruct the device to segment via the PRDCH may be transmitted. The device may explicitly determine D2R data segmentation from the segmentation indicators included in the PRDCH message. The PRDCH message may include reference information for D2R data segmentation, such as the maximum resource size required to transmit one segment and / or the maximum number of bits per segment.

[0201] Alternatively, the device may implicitly determine segmentation when the number of dedicated resources included in the PRDCH message is multiple. Here, the device may implicitly determine segmentation if the size or number of the allocated multiple dedicated resources is sufficient to transmit the entire D2R data, or if the D2R data size is greater than a threshold. This is intended to address the problem where the amount of data that must be retransmitted increases as the D2R data size increases in the event of a transmission failure. For example, if D2R data of the maximum size (1000 bits) is transmitted without segmentation and the transmission fails, the entire D2R data must be retransmitted, which can lead to wasted time and resources. However, if the device classifies the D2R data into multiple segments before transmission, the device can transmit only the failed segments even if some segments fail to transmit, which can be efficient in terms of dedicated resources and time. When considering a 1 or 2-bit segment field for segment separation, the resource waste caused by segmentation can be seen as minimal.

[0202] Step 2: Transmit [Device → Reader] segment

[0203] The device can transmit D2R segments to the reader using all or part of the multiple D2R-dedicated resources allocated from the PRDCH message. If the device receives information on i D2R-dedicated resources and can transmit the entire D2R data using fewer than i resources, then j(j <i)개의 전용 자원을 통해 j개의 세그먼트를 전송할 수 있다. 또는, 디바이스는 자신이 전송할 D2R 데이터 사이즈가 리더로부터 할당된 i개의 전용 자원 크기보다 큰 이유로, 할당 받은 D2R 자원만으로 전체 D2R 데이터를 전송할 수 없는 경우에는 i(j=i)개의 전용 자원을 통해 D2R 세그먼트들을 전송함과 동시에 추가적인 자원 할당을 요청할 수 있다.

[0204] When selecting a resource to transmit segments from among the multiple dedicated resources, the device may transmit segments by allocating them in a time-first order, in a frequency-first order, or in an order with less frequency shift. A segment may consist of a data field in which A-IoT data (or D2R data) is stored and a segment field of 1 or 2 bits in size indicating whether the segment is the last segment.

[0205] Step 3: [Reader] Configure bitmap based on success of segment reception

[0206] The reader can determine whether a segment has been successfully received or failed based on the D2R dedicated resource information allocated to the device, and can configure a bitmap indicating the success or failure of segment reception per D2R dedicated resource. A D2R dedicated resource may refer to a resource of maximum size classified into time / frequency domains capable of transmitting one segment, and this may be defined as a slot, bit, or time unit. The reader can configure the bitmap by storing a '1' bit if the device succeeds in receiving a segment transmitted through the D2R dedicated resource, and a '0' bit if the segment reception fails.

[0207] As an example of bitmap configuration following the successful reception of a D2R segment by a reader, if the reader successfully receives i segments from the device using i D2R resources allocated to it, it can create a bitmap composed of i '1' bits such as [1 1 1 1 ...].

[0208] Alternatively, the reader may have allocated four dedicated D2R resources, but the device may classify and transmit the entire D2R data into three segments using three dedicated D2R resources. In this case, since the reader did not receive a segment from the fourth D2R resource allocated to it, it may determine that segment reception failed and simultaneously construct a bitmap such as [1 1 1 0]. However, based on the last segment indication stored in the segment field of the third, or last, segment transmitted by the device, the reader can determine that the device transmitted the entire D2R data using only three dedicated D2R resources and did not transmit a segment from the fourth resource. Therefore, the reader can determine that the entire D2R data was successfully received and may construct a bitmap in the form of [1 1 1 1].

[0209] As an example of bitmap configuration following a reader's failure to receive D2R segments, the reader has allocated 4 dedicated D2R resources, and the device has transmitted 4 segments through these 4 dedicated D2R resources, but may fail to transmit the 4th D2R segment. In this case, since the reader did not receive a segment from the 4th resource it allocated, it may configure a bitmap in the form of [1 1 1 0]. Here, the reader may configure the bitmap as [0 0 0 0] for the purpose of instructing the device to retransmit all D2R segments if even one segment fails to be received.

[0210] As another example, a reader may have allocated four D2R resources, and a device may have transmitted three segments using three of the four dedicated D2R resources, but fail to transmit the second segment. In this case, the reader may construct a bitmap like [1 0 1 0] because it did not receive segments from the second and fourth D2R resources it allocated. However, the reader can determine that the device did not transmit a segment from the fourth resource based on the last segment indication stored in the segment field of the last segment transmitted by the device. Additionally, the reader can determine that it failed to receive a segment from the second D2R resource and, accordingly, may construct the bitmap as [1 0 1 1]. Here, the reader may also construct the bitmap as [0 0 0 0] for the purpose of instructing the device to retransmit all D2R segments if even one segment fails to be received.

[0211] Step 4: [Reader → Device] Segment reception success / failure and retransmission instructions

[0212] The reader can notify the device of the success or failure of D2R segment transmission.

[0213] If the reader succeeds in receiving a D2R segment, it may send a D2R transmission success message to the device with a size of 1 bit, or include a bitmap such as [1 1 1 쪋] in the message. Alternatively, by not sending a message such as the D2R transmission success message, the reader may be configured to implicitly know that the segments it transmitted have been successfully received. As another example, the reader may send a D2R segments Tx success message only when all D2R segments have been successfully received. A device that does not receive such a message may determine that the D2R segment transmission failed and retransmit previously transmitted segments.

[0214] If the reader fails to receive a D2R segment, it may instruct the device to retransmit by including the bitmap information described above and information regarding D2R-dedicated allocated resources within a D2R transmission failure message. Here, the number or size of the D2R-dedicated allocated resources may be configured based on the number or size of segments that the reader failed to receive. For example, if the reader fails to receive two D2R segments, it may allocate D2R-dedicated resources with a size corresponding to two segments to grant the device a retransmission opportunity. As another example, if the reader fails to receive even a single D2R segment, it may instruct the device to retransmit all D2R segments.

[0215] Step 5: [Device → Reader] Segment Retransmission

[0216] The device can determine whether to perform retransmission based on D2R segment transmission success / failure information received from the reader.

[0217] If the device receives a D2R segment transmission success message from the reader, the device may decide not to perform retransmission. Alternatively, if the device does not receive segment transmission success or failure messages from the reader for a certain time interval after transmitting the D2R segment, the device may implicitly determine that the D2R segment it transmitted was successfully transmitted. Here, arbitrary time interval information for the device to implicitly determine that the D2R segment was successfully transmitted may be a value pre-configured or pre-defined by the reader. The time interval information is [T D2R_min , T D2R_max It may be a parameter that takes into account the processing time of a device such as ] or a parameter that the reader sets by taking into account the expected D2R message size.

[0218] When a device receives a D2R segment transmission failure message from a reader, the device may decide to perform retransmission. The device can identify the D2R segment that failed to transmit based on the bitmap information within the message and the D2R-dedicated resource information it used for segment transmission. The device can retransmit only the failed segment using additional D2R-dedicated resources within the message.

[0219] Step 6: [Reader → Device] Check segment reception success / failure and instruct retransmission (Repeat Step 4)

[0220] If the reader sends a D2R transmission failure message to the device in step 4, the reader may expect to receive a D2R segment retransmission. The reader's action regarding the success or failure of receiving the D2R segment retransmission may follow the details described in step 4.

[0221] FIG. 16 is a flowchart illustrating a method of operation of a device according to one embodiment of the present specification.

[0222] Referring to FIG. 16, the device receives ACK / NACK (Acknowledgement / Negative Acknowledgement) information regarding the transmission of a D2R segment from the reader (S1601). The ACK / NACK information may be received included in a D2R transmission success message or a D2R transmission failure message. Based on the received ACK / NACK information, the device determines whether to retransmit the D2R segment. If it is determined that retransmission of the D2R segment is required, the device performs the retransmission of the corresponding D2R segment (S1602).

[0223] FIGS. 17 and 18 illustrate procedures between a reader and a device according to one embodiment of the present specification.

[0224] Hereinafter, the operation of an A-IoT device will be described in detail with reference to FIGS. 17 and 18.

[0225] 1. A device receives a PRDCH message from a reader (e.g., a base station) containing resource information for D2R data transmission. The PRDCH message may include time / frequency / code-based D2R dedicated resource information required for the device's D2R data transmission. Additionally, the PRDCH message may include at least one of the following information.

[0226] Resource allocation order instruction information. This may include information instructing the device to allocate resources in the order of least frequency shift, time-first, frequency-first, or when selecting multiple resources for segment transmission from among D2R-dedicated resources. Here, time / frequency / code-based D2R-dedicated resources may be allocated by considering the expected D2R message size received from the CN or the device.

[0227] Segmentation instruction information. This means that it is an indicator that explicitly instructs the device to perform D2R data segmentation.

[0228] The maximum number of bits per segment. This refers to the maximum number of bits that make up one segment when segmenting D2R data.

[0229] Maximum number of bits per D2R dedicated resource. This means the maximum number of bits that can be transmitted through a single D2R dedicated resource.

[0230] Time interval information. This indicates the time interval from the time of D2R segment transmission during which the device waits for a success or failure acknowledgment message from the reader. For example, if the device does not receive a segment transmission success message from the reader during this time interval, it may determine that the D2R segment transmission was successful.

[0231] 2. The device determines whether to perform D2R data segmentation based on the received PRDCH message.

[0232] For example, if there is segmentation instruction information within the PRDCH message, namely the D2R data segmentation instruction, the device performs segmentation.

[0233] As another example, if there is no D2R data segmentation indicator in the PRDCH message but multiple D2R-dedicated resources are included, the device can implicitly determine D2R data segmentation.

[0234] As another example, if there is no D2R data segmentation indicator in the PRDCH message, the device can determine D2R data segmentation if the D2R data size is greater than a threshold previously set by the reader.

[0235] 3. The device transmits D2R segments through a dedicated D2R resource based on the resource information of the received PRDCH message.

[0236] The device can transmit segments by allocating the corresponding D2R dedicated resources in a time-first or frequency-first order according to the instructions of the reader or pre-configured / pre-defined information.

[0237] Additionally, considering the size of the D2R data, the device may transmit segments using all or some of the D2R-dedicated resources based on the resource information in the received PRDCH message. For example, the device may transmit D2R segments by selecting i D2R-dedicated resources from among i D2R-dedicated resources. In this case, if the size of the D2R-dedicated resources is too small to transmit the entire D2R data, the device may request the allocation of additional D2R-dedicated resources along with the segment transmission. Alternatively, the device may transmit D2R segments by selecting only j D2R-dedicated resources from among i D2R-dedicated resources.

[0238] 4. The device receives a D2R segment transmission success (D2R segments Tx success) message from the reader.

[0239] The device may determine that the D2R segment has been successfully transmitted after receiving a D2R segment transmission success message. Here, the success message may be a 1-bit indication message or a message containing bitmap information.

[0240] Alternatively, the device may determine that the D2R segment was successfully transmitted if it does not receive the corresponding success message during the time interval obtained from the reader.

[0241] Hereinafter, with reference to FIGS. 17 and 18, the operation of a reader (e.g., a base station) will be described in detail.

[0242] 1. The reader transmits a PRDCH message containing resource information for D2R data transmission to the device. The PRDCH message may include time / frequency / code-based D2R dedicated resource information required for the device's D2R data transmission. Additionally, the PRDCH message may include at least one of the following information.

[0243] Resource allocation order instruction information. This may include information instructing the device to allocate resources in the order of least frequency shift, time-first, frequency-first, or when selecting multiple resources for segment transmission from among D2R-dedicated resources. Here, time / frequency / code-based D2R-dedicated resources may be allocated by considering the expected D2R message size received from the CN or the device.

[0244] Segmentation instruction information. This means that it is an indicator that explicitly instructs the device to perform D2R data segmentation.

[0245] The maximum number of bits per segment. This refers to the maximum number of bits that make up one segment when segmenting D2R data.

[0246] Maximum number of bits per D2R dedicated resource. This means the maximum number of bits that can be transmitted through a single D2R dedicated resource.

[0247] Time interval information. This indicates the time interval from the time of D2R segment transmission during which the device waits for a success or failure acknowledgment message from the reader. For example, if the device does not receive a segment transmission success message from the reader during this time interval, it may determine that the D2R segment transmission was successful.

[0248] 2. The reader configures a bitmap considering the D2R segment reception status from the device.

[0249] Referring to FIG. 17, the reader receives i segments through i D2R resources allocated to the device. That is, the reader allocated 3 D2R dedicated resources, and since it succeeded in receiving 3 segments through all allocated resources, it can construct a bitmap in the form of

[0111] .

[0250] Referring to FIG. 18, the reader receives j segments through i D2R resources allocated to the device. That is, the reader allocated 4 dedicated D2R resources, and since it succeeded in receiving 3 segments through 3 of the allocated resources based on time-first, it can construct a bitmap in the form of [1 1 1 0]. However, since it can be seen from the last segment indication information in the last D2R segment that all D2R segments were successfully received, it can also be constructed as a bitmap like [1 1 1 1].

[0251] If a device requests the allocation of additional D2R resources because it cannot transmit all D2R data with only the allocated D2R dedicated resources, the reader may allocate additional resources.

[0252] 3. The reader sends a D2R segments Tx success message to the device.

[0253] The success message may be a 1-bit indication message or a message containing bitmap information.

[0254] Alternatively, if the D2R segment is successfully received, the reader may not send a separate success message.

[0255] FIGS. 19 and 20 illustrate procedures between a reader and a device according to another embodiment of the present specification.

[0256] Hereinafter, the operation of an A-IoT device will be described in detail with reference to FIGS. 19 and 20.

[0257] 1. A device receives a PRDCH message from a reader (e.g., a base station) containing resource information for D2R data transmission. The PRDCH message may include time / frequency / code-based D2R dedicated resource information required for the device's D2R data transmission. Additionally, the PRDCH message may include at least one of the following information.

[0258] Resource allocation order instruction information. This may include information instructing the device to allocate resources in the order of least frequency shift, time-first, frequency-first, or when selecting multiple resources for segment transmission from among D2R-dedicated resources. Here, time / frequency / code-based D2R-dedicated resources may be allocated by considering the expected D2R message size received from the CN or the device.

[0259] Segmentation instruction information. This means that it is an indicator that explicitly instructs the device to perform D2R data segmentation.

[0260] The maximum number of bits per segment. This refers to the maximum number of bits that make up one segment when segmenting D2R data.

[0261] Maximum number of bits per D2R dedicated resource. This means the maximum number of bits that can be transmitted through a single D2R dedicated resource.

[0262] Time interval information. This indicates the time interval from the time of D2R segment transmission during which the device waits for a success or failure acknowledgment message from the reader. For example, if the device does not receive a segment transmission success message from the reader during this time interval, it may determine that the D2R segment transmission was successful.

[0263] 2. The device determines whether to perform D2R data segmentation based on the received PRDCH message.

[0264] For example, if there is segmentation instruction information within the PRDCH message, namely the D2R data segmentation instruction, the device performs segmentation.

[0265] As another example, if there is no D2R data segmentation indicator in the PRDCH message but multiple D2R-dedicated resources are included, the device can implicitly determine D2R data segmentation.

[0266] As another example, if there is no D2R data segmentation indicator in the PRDCH message, the device can determine D2R data segmentation if the D2R data size is greater than a threshold previously set by the reader.

[0267] 3. The device transmits D2R segments through a dedicated D2R resource based on the resource information of the received PRDCH message.

[0268] The device can transmit segments by allocating the corresponding D2R dedicated resources in a time-first or frequency-first order according to the instructions of the reader or pre-configured / pre-defined information.

[0269] Additionally, considering the size of the D2R data, the device may transmit segments using all or some of the D2R-dedicated resources based on the resource information in the received PRDCH message. For example, the device may transmit D2R segments by selecting i D2R-dedicated resources from among i D2R-dedicated resources. In this case, if the size of the D2R-dedicated resources is too small to transmit the entire D2R data, the device may request the allocation of additional D2R-dedicated resources along with the segment transmission. Alternatively, the device may transmit D2R segments by selecting only j D2R-dedicated resources from among i D2R-dedicated resources.

[0270] 4. The device receives a D2R segments Tx failure message from the reader and retransmits the segment(s) that failed to be transmitted to the reader.

[0271] The device retransmits the D2R segment(s) that failed to transmit through the additionally allocated D2R dedicated resources from the corresponding failure message.

[0272] The device can identify the segment(s) that failed to transmit based on the bitmap information included in the failure message and the D2R-specific resource information it transmitted.

[0273] Referring to FIG. 19, when the device receives a bitmap such as [1 0 1 1], it can retransmit the second segment on a time-first basis.

[0274] Referring to FIG. 20, when the device receives a bitmap such as [1 0 0 0], the device can retransmit only the 2nd and 3rd segments because it did not transmit the 4th segment.

[0275] 5. The device receives a D2R segment transmission success message from the reader.

[0276] The device may determine that the D2R segment has been successfully transmitted after receiving a D2R segment transmission success message. Here, the success message may be a 1-bit indication message or a message containing bitmap information.

[0277] Alternatively, the device may determine that the D2R segment was successfully transmitted if it does not receive the corresponding success message during the time interval obtained from the reader.

[0278] Hereinafter, with reference to FIGS. 19 and 20, the operation of a reader (e.g., a base station) will be described in detail.

[0279] 1. The reader transmits a PRDCH message containing resource information for D2R data transmission to the device. The PRDCH message may include time / frequency / code-based D2R dedicated resource information required for the device's D2R data transmission. Additionally, the PRDCH message may include at least one of the following information.

[0280] Resource allocation order instruction information. This may include information instructing the device to allocate resources in the order of least frequency shift, time-first, frequency-first, or when selecting multiple resources for segment transmission from among D2R-dedicated resources. Here, time / frequency / code-based D2R-dedicated resources may be allocated by considering the expected D2R message size received from the CN or the device.

[0281] Segmentation instruction information. This means that it is an indicator that explicitly instructs the device to perform D2R data segmentation.

[0282] The maximum number of bits per segment. This refers to the maximum number of bits that make up one segment when segmenting D2R data.

[0283] Maximum number of bits per D2R dedicated resource. This means the maximum number of bits that can be transmitted through a single D2R dedicated resource.

[0284] Time interval information. This indicates the time interval from the time of D2R segment transmission during which the device waits for a success or failure acknowledgment message from the reader. For example, if the device does not receive a segment transmission success message from the reader during this time interval, it may determine that the D2R segment transmission was successful.

[0285] 2. The reader configures a bitmap considering the D2R segment reception status from the device.

[0286] Referring to FIG. 19, the case where the reader fails to receive a segment other than the last segment is explained. Referring to FIG. 19, the reader has allocated four D2R dedicated resources and has succeeded in receiving two segments through two of the allocated resources based on time-first criteria, so a bitmap such as [1 0 1 0] can be constructed. However, since it can be seen from the last segment indication information within the last D2R segment that the device did not transmit a segment through the fourth D2R resource, a bitmap such as [1 0 1 1] can also be constructed.

[0287] Referring to FIG. 20, the case where the reader fails to receive the last segment is explained. Referring to FIG. 20, the reader has allocated four D2R dedicated resources, and since it succeeded in receiving one segment through one of the allocated resources based on time-first criteria, it can construct a bitmap such as [1 0 0 0]. In this case, the reader maintains the [1 0 0 0] bitmap because it did not receive a segment containing last segment indication information.

[0288] 3. The reader sends a D2R segments Tx failure message to the device.

[0289] The failure message may include bitmap information along with additional D2R resource allocation information corresponding to the failure to receive segment(s). This is information regarding resources additionally allocated by the reader when the device requests additional D2R resource allocation because it cannot transmit the entire D2R data using only the allocated D2R-only resources.

[0290] Referring to FIG. 19, when a segment containing last segment indication information is successfully received, the reader can determine the number / size of segments transmitted by the device and the number / size of segments that failed to be received, and thus can allocate additional D2R dedicated resources corresponding to the size of the segment(s) that failed to be received.

[0291] Referring to FIG. 20, when the reader fails to receive a segment containing last segment indication information, the reader cannot know the number / size of segments transmitted by the device and the number / size of segments that failed to be received, so it can additionally allocate D2R dedicated resources consisting of a number of '0' bits in the bitmap.

[0292] 4. The reader sends a D2R segment success message to the device.

[0293] The success message may be a 1-bit indication message or a message containing bitmap information.

[0294] Alternatively, if the D2R segment is successfully received, the reader may not send a separate success message.

[0295] FIG. 21 is a flowchart illustrating a method of operation of a device according to another embodiment of the present specification.

[0296] Referring to FIG. 21, the device divides Device-to-Reader (D2R) data into a plurality of segments (S2101) and transmits the plurality of segments to a reader through a first D2R resource (S2102). Additionally, the device receives transmission status information in response to the transmitted plurality of segments (S2203), and based on the received transmission status information, retransmits at least one of the transmitted plurality of segments through a second D2R resource (S2104).

[0297] The device can receive a PRDCH (Physical Reader to Device Channel) message from a reader, and the PRDCH message may include information about the first D2R resource.

[0298] The above PRDCH message may further include partition instruction information, and the D2R data may be partitioned into the plurality of segments based on the partition instruction information.

[0299] The information regarding the first D2R resource may include information on a plurality of D2R transmission resources constituting the first D2R resource, and the D2R data may be divided into the plurality of segments based on the information of the plurality of D2R transmission resources.

[0300] Meanwhile, the above transmission status information may be composed of a bitmap.

[0301] Information regarding the second resource may be received along with the transmission status information, and the information regarding the second D2R resource may include information on at least one D2R transmission resource constituting the second resource, wherein the number of the at least one D2R transmission resource may correspond to the number of bits indicating transmission failure by the bitmap.

[0302] On the other hand, the plurality of segments may belong to a single segment group, and the retransmission of at least one segment may include the retransmission of all the plurality of segments belonging to the single segment group.

[0303] The above PRDCH message may further include time interval information for monitoring the transmission status information, and if the transmission status information is not received during the time interval according to the time interval information, the plurality of segments may be considered to have been successfully transmitted.

[0304] Information regarding the first D2R resource above may be based on expected D2R message size information transmitted from the core network or the device.

[0305] Additionally, the PRDCH message may further include at least one of information on the maximum number of bits per segment and information on the maximum number of bits per D2R transmission resource.

[0306] The disclosures of this specification described above may be implemented through various means. For example, the disclosures of this specification may be implemented by hardware, firmware, software, or a combination thereof. Specifically, they will be described below with reference to the drawings.

[0307] FIG. 22 shows an apparatus according to one embodiment of the present specification.

[0308] Referring to FIG. 22, the wireless communication system may include a first device (100a) and a second device (100b).

[0309] The first device (100a) may be a base station, network node, transmission terminal, receiving terminal, wireless device, wireless communication device, vehicle, vehicle equipped with autonomous driving function, connected car, drone (Unmanned Aerial Vehicle, UAV), AI (Artificial Intelligence) module, robot, AR (Augmented Reality) device, VR (Virtual Reality) device, MR (Mixed Reality) device, hologram device, public safety device, MTC device, IoT device, medical device, fintech device (or financial device), security device, climate / environment device, device related to 5G service, or other device related to the field of the Fourth Industrial Revolution.

[0310] The second device (100b) may be a base station, network node, transmission terminal, receiving terminal, wireless device, wireless communication device, vehicle, vehicle equipped with autonomous driving function, connected car, drone (Unmanned Aerial Vehicle, UAV), AI (Artificial Intelligence) module, robot, AR (Augmented Reality) device, VR (Virtual Reality) device, MR (Mixed Reality) device, hologram device, public safety device, MTC device, IoT device, medical device, fintech device (or financial device), security device, climate / environment device, device related to 5G service, or other device related to the field of the Fourth Industrial Revolution.

[0311] The first device (100a) may include at least one processor, such as a processor (1020a), at least one memory, such as a memory (1010a), and at least one transceiver, such as a transceiver (1031a). The processor (1020a) may perform the aforementioned functions, procedures, and / or methods. The processor (1020a) may perform one or more protocols. For example, the processor (1020a) may perform one or more layers of a wireless interface protocol. The memory (1010a) is connected to the processor (1020a) and may store various forms of information and / or commands. The transceiver (1031a) is connected to the processor (1020a) and may be controlled to transmit and receive wireless signals.

[0312] The second device (100b) may include at least one processor, such as a processor (1020b), at least one memory device, such as a memory (1010b), and at least one transceiver, such as a transceiver (1031b). The processor (1020b) may perform the aforementioned functions, procedures, and / or methods. The processor (1020b) may implement one or more protocols. For example, the processor (1020b) may implement one or more layers of a wireless interface protocol. The memory (1010b) is connected to the processor (1020b) and may store various forms of information and / or commands. The transceiver (1031b) is connected to the processor (1020b) and may be controlled to transmit and receive wireless signals.

[0313] The memory (1010a) and / or the memory (1010b) may be connected to the processor (1020a) and / or the processor (1020b) respectively, either internally or externally, and may also be connected to other processors through various technologies such as wired or wireless connections.

[0314] The first device (100a) and / or the second device (100b) may have one or more antennas. For example, the antenna (1036a) and / or antenna (1036b) may be configured to transmit and receive wireless signals.

[0315] FIG. 23 is a block diagram showing the configuration of a terminal according to one embodiment of the present specification.

[0316] In particular, FIG. 23 is a drawing illustrating the device of FIG. 22 in more detail.

[0317] The device includes a memory (1010), a processor (1020), a transceiver (1031), a power management module (1091), a battery (1092), a display (1041), an input unit (1053), a speaker (1042) and a microphone (1052), a SIM (subscriber identification module) card, and one or more antennas.

[0318] The processor (1020) may be configured to implement the proposed functions, procedures, and / or methods described herein. Layers of a radio interface protocol may be implemented in the processor (1020). The processor (1020) may include an application-specific integrated circuit (ASIC), other chipsets, logic circuits, and / or data processing devices. The processor (1020) may be an application processor (AP). The processor (1020) may include at least one of a digital signal processor (DSP), a central processing unit (CPU), a graphics processing unit (GPU), and a modem (modulator and demodulator). Examples of processors (1020) may be SNAPDRAGON™ series processors manufactured by Qualcomm®, EXYNOSTM series processors manufactured by Samsung®, A series processors manufactured by Apple®, HELIO™ series processors manufactured by MediaTek®, ATOM™ series processors manufactured by INTEL®, KIRINTM series processors manufactured by HiSilicon®, or corresponding next-generation processors.

[0319] The power management module (1091) manages power for the processor (1020) and / or the transceiver (1031). The battery (1092) supplies power to the power management module (1091). The display (1041) outputs the results processed by the processor (1020). The input unit (1053) receives input to be used by the processor (1020). The input unit (1053) may be displayed on the display (1041). A SIM card is an integrated circuit used to securely store the International Mobile Subscriber Identity (IMSI) and associated keys used to identify and authenticate a subscriber in mobile devices such as mobile phones and computers. Contact information may also be stored on many SIM cards.

[0320] Memory (1010) is operably coupled with the processor (1020) and stores various information for operating the processor (610). Memory (1010) may include ROM (read-only memory), RAM (random access memory), flash memory, memory card, storage medium and / or other storage device. Where the embodiment is implemented in software, the techniques described herein may be implemented as modules (e.g., procedures, functions, etc.) that perform the functions described herein. Modules may be stored in memory (1010) and executed by the processor (1020). Memory (1010) may be implemented inside the processor (1020). Alternatively, memory (1010) may be implemented outside the processor (1020) and may be communically connected to the processor (1020) through various means known in the art.

[0321] The transceiver (1031) is operably coupled with the processor (1020) and transmits and / or receives a wireless signal. The transceiver (1031) includes a transmitter and a receiver. The transceiver (1031) may include a baseband circuit for processing a wireless frequency signal. The transceiver controls one or more antennas to transmit and / or receive a wireless signal. The processor (1020) transmits command information to the transceiver (1031) to transmit a wireless signal, for example, constituting voice communication data, in order to initiate communication. The antennas function to transmit and receive wireless signals. When receiving a wireless signal, the transceiver (1031) may transmit the signal to the processor (1020) for processing and convert the signal to baseband. The processed signal may be converted into audible or readable information output through a speaker (1042).

[0322] The speaker (1042) outputs sound-related results processed by the processor (1020). The microphone (1052) receives sound-related input to be used by the processor (1020).

[0323] The user inputs command information, such as a phone number, by, for example, pressing (or touching) a button on the input unit (1053) or by voice activation using the microphone (1052). The processor (1020) receives this command information and processes it to perform appropriate functions, such as making a call to the phone number. Operational data can be extracted from a SIM card or memory (1010). Additionally, the processor (1020) can display the command information or operation information on the display (1041) for the user's awareness and convenience.

[0324] FIG. 24 shows a block diagram of a processor in which the disclosure of the present specification is implemented.

[0325] As can be seen with reference to FIG. 24, a processor (1020) in which the disclosure of this specification is implemented may include a plurality of circuits to implement the proposed functions, procedures and / or methods described in this specification. For example, the processor (1020) may include a first circuit (1020-1), a second circuit (1020-2), and a third circuit (1020-3). Additionally, although not illustrated, the processor (1020) may include more circuits. Each circuit may include a plurality of transistors.

[0326] The above processor (1020) may be called an ASIC (application-specific integrated circuit) or an AP (application processor), and may include at least one of a DSP (digital signal processor), a CPU (central processing unit), and a GPU (graphics processing unit).

[0327] FIG. 25 is a block diagram showing in detail the transceiver of the first device shown in FIG. 22 or the transceiver of the device shown in FIG. 23.

[0328] Referring to FIG. 25, the transceiver unit (1031) includes a transmitter (1031-1) and a receiver (1031-2). The transmitter (1031-1) includes a Discrete Fourier Transform (DFT) unit (1031-11), a subcarrier mapper (1031-12), an IFFT unit (1031-13), a CP insertion unit (1031-14), and a wireless transmitter (1031-15). The transmitter (1031-1) may further include a modulator. Additionally, it may further include, for example, a scramble unit (not shown), a modulation mapper (not shown), a layer mapper (not shown), and a layer permutator (not shown), which may be positioned prior to the DFT unit (1031-11). That is, to prevent an increase in the PAPR (peak-to-average power ratio), the transmitter (1031-1) first passes the information through the DFT (1031-11) before mapping the signal to the subcarrier. After the signal spread (or precoded in the same sense) by the DFT section (1031-11) is mapped to the subcarrier through the subcarrier mapper (1031-12), it is then passed through the IFFT (Inverse Fast Fourier Transform) section (1031-13) to form a signal on the time axis.

[0329] The DFT unit (1031-11) performs a DFT on the input symbols to output complex-valued symbols. For example, if Ntx symbols are input (where Ntx is a natural number), the DFT size is Ntx. The DFT unit (1031-11) may be called a transform precoder. The subcarrier mapper (1031-12) maps the complex-valued symbols to each subcarrier in the frequency domain. The complex-valued symbols may be mapped to resource elements corresponding to resource blocks allocated for data transmission. The subcarrier mapper (1031-12) may be called a resource element mapper. The IFFT unit (1031-13) performs an IFFT on the input symbols to output a baseband signal for the data, which is a time-domain signal. The CP insertion section (1031-14) copies a portion of the latter part of the base band signal for data and inserts it into the front part of the base band signal for data. Through CP insertion, Inter-Symbol Interference (ISI) and Inter-Carrier Interference (ICI) are prevented, so that orthogonality can be maintained even in a multipath channel.

[0330] On the other hand, the receiver (1031-2) includes a wireless receiver (1031-21), a CP removal unit (1031-22), an FFT unit (1031-23), and an equalization unit (1031-24), etc. The wireless receiver (1031-21), CP removal unit (1031-22), and FFT unit (1031-23) of the receiver (1031-2) perform the inverse functions of the wireless transmitter (1031-15), CP insertion unit (1031-14), and IFF unit (1031-13) of the transmitter (1031-1). The receiver (1031-2) may further include a demodulator.

[0331] Although preferred embodiments have been described by way of example above, the disclosure of this specification is not limited to such specific embodiments, and may be modified, changed, or improved in various forms within the scope of the spirit and claims of this specification.

[0332] In the exemplary system described above, methods are described based on a flowchart as a series of steps or blocks, but are not limited to the order of the described steps, and some steps may occur in a different order or simultaneously with other steps as described above. Furthermore, a person skilled in the art will understand that the steps shown in the flowchart are not exclusive, and that other steps may be included, or that one or more steps of the flowchart may be omitted without affecting the scope of rights.

[0333] The claims described in this specification may be combined in various ways. For example, the technical features of the method claims in this specification may be combined to be implemented as a device, and the technical features of the device claims in this specification may be combined to be implemented as a method. Furthermore, the technical features of the method claims and the technical features of the device claims in this specification may be combined to be implemented as a device, and the technical features of the method claims and the technical features of the device claims in this specification may be combined to be implemented as a method.

Claims

1. In a method of operating a device in a wireless communication system, A step of dividing D2R (Device-to-Reader) data into multiple segments; A step of transmitting the above plurality of segments through a first D2R resource; A step of receiving transmission status information in response to the plurality of segments transmitted above; and A method comprising the step of retransmitting at least one of the transmitted segments through a second D2R resource based on the received transmission status information.

2. In Paragraph 1, It further includes the step of receiving a PRDCH (Physical Reader to Device Channel) message, A method in which the above PRDCH message includes information about the above first D2R resource.

3. In Paragraph 2, The above PRDCH message further includes partition instruction information, and A method in which the D2R data is divided into the plurality of segments based on the above division instruction information.

4. In Paragraph 2, The information regarding the first D2R resource includes information on a plurality of D2R transmission resources constituting the first D2R resource, and A method in which the D2R data is divided into the plurality of segments based on information of the plurality of D2R transmission resources.

5. In Paragraph 1, A method in which the above transmission status information is composed of a bitmap.

6. In Paragraph 5, Information regarding the second resource is received along with the transmission status information, and The information regarding the second D2R resource includes information on at least one D2R transmission resource constituting the second resource, and A method in which the number of at least one D2R transmission resource corresponds to the number of bits indicating transmission failure by the bitmap.

7. In Paragraph 1, The above plurality of segments belong to a single segment group, and A method in which the retransmission of at least one segment includes the retransmission of all of the plurality of segments belonging to the one segment group.

8. In Paragraph 2, The above PRDCH message further includes time interval information for monitoring the transmission status information, and A method in which, if the transmission status information is not received during the time interval according to the above time interval information, the plurality of segments are considered to have been successfully transmitted.

9. In Paragraph 2, A method in which information regarding the first D2R resource is based on expected D2R message size information transmitted from the core network or the device.

10. In Paragraph 4, A method in which the above PRDCH message further includes at least one of information on the maximum number of bits per segment and information on the maximum number of bits per D2R transmission resource.

11. As a device in a wireless communication system, At least one processor; and The operation performed based on the instruction being executed by the at least one processor includes at least one memory that stores instructions and is operablely electrically connected to the at least one processor: A step of dividing D2R (Device-to-Reader) data into multiple segments; A step of transmitting the above plurality of segments through a first D2R resource; A step of receiving transmission status information in response to the plurality of segments transmitted above; and A device comprising the step of retransmitting at least one of the transmitted segments through a second D2R resource based on the received transmission status information.

12. In Paragraph 11, Based on the execution of the above instruction by the at least one processor, the operation performed is: It further includes the step of receiving a PRDCH (Physical Reader to Device Channel) message, The above PRDCH message is a device containing information about the first D2R resource.

13. In Paragraph 11, The above PRDCH message further includes partition instruction information, and A device in which the D2R data is divided into the plurality of segments based on the above division instruction information.

14. In Paragraph 12, The information regarding the first D2R resource includes information on a plurality of D2R transmission resources constituting the first D2R resource, and A device in which the D2R data is divided into the plurality of segments based on information of the plurality of D2R transmission resources.

15. In Paragraph 11, A device in which the above transmission status information is composed of a bitmap.

16. In Paragraph 15, Information regarding the second resource is received along with the transmission status information, and The information regarding the second D2R resource includes information on at least one D2R transmission resource constituting the second resource, and The number of at least one D2R transmission resource corresponds to the number of bits indicating transmission failure by the bitmap, in a device.

17. In Paragraph 11, The above plurality of segments belong to a single segment group, and A device in which the retransmission of at least one segment includes the retransmission of all of the plurality of segments belonging to the one segment group.

18. In Paragraph 12, The above PRDCH message further includes time interval information for monitoring the transmission status information, and A device in which, if the transmission status information is not received during the time interval according to the above time interval information, the plurality of segments are considered to have been successfully transmitted.

19. In Paragraph 12, A device in which information regarding the first D2R resource is based on expected D2R message size information transmitted from the core network or the device.

20. In Paragraph 14, A device in which the above PRDCH message further includes at least one of information on the maximum number of bits per segment and information on the maximum number of bits per D2R transmission resource.

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