Communication method

Abstract

A communication method according to one aspect of the present invention is used in a moving communication system. The communication method has a step in which an ambient Internet of Things (IoT) device receives a Reader-to-Device (R2D) message, which includes device identifying information that identifies the ambient IoT device, from a reader device, which is a user device or a network node of the moving communication system. Moreover, the communication method has a step in which the ambient IoT device determines an access method to the reader device on the basis of the device identifying information. Still further, the communication method has a step in which the ambient IoT device transmits a Device-to-Reader (D2R) message to the reader device in accordance with the access method.

Description

Communication Method

[0001] The present disclosure relates to a communication method for use in a mobile communication system.

[0002] In recent years, the Internet of Things (IoT) has been attracting attention in wireless communication technology. It is expected that interconnecting more "things" will improve production efficiency and enhance the comfort of daily life compared to the past. Technologies used in IoT include barcodes and radio frequency identifiers (RFIDs). However, barcodes and RFIDs cannot perform long-distance wireless communication, making it difficult to support large-scale networks.

[0003] Therefore, the Third Generation Partnership Project (3GPP) (registered trademark, hereinafter the same), a standardization project for mobile communication systems, is studying the feasibility of new IoT technologies. This IoT technology is expected to have a higher number of connections and a higher device density than existing 3GPP IoT technologies, such as NB-IoT (Narrow Band-IoT) or LTE-MTC (Long Term Evolution-Machine Type Communication). Furthermore, this IoT technology is expected to have lower complexity and power consumption than existing 3GPP LPWA (Low Power Wide Area) technology. An IoT device used in this IoT technology is called an ambient IoT device.

[0004] Most existing wireless communication devices use batteries that must be manually replaced and / or charged. However, powering all IoT devices with batteries is difficult because it requires not only the cost of the IoT devices themselves but also the maintenance costs for the IoT devices.

[0005] The above-mentioned ambient IoT devices are envisioned to function as battery-less devices with no energy storage capabilities, in which case the ambient IoT devices function as pure battery-less devices with no power storage capabilities whatsoever and are completely dependent on the availability of an external energy source.

[0006] Alternatively, ambient IoT devices are envisioned to function as battery devices with limited energy storage, e.g., energy storage that does not require manual replacement and / or charging.

[0007] The use of such ambient IoT devices is expected to lead to automation and digitalization in various industries, as well as the development of new markets.

[0008] 3GPP TR 38.848 V18.0.0 (2023-09)

[0009] The present disclosure provides a communication method that enables appropriate communication between a reader device and an ambient IoT device.

[0010] A communication method according to a first aspect is a communication method used in a mobile communication system. The communication method includes a step in which an ambient Internet of Things (IoT) device receives a Reader-to-Device (R2D) message including device identification information identifying the ambient IoT device from a reader device that is a network node or user equipment of the mobile communication system. The communication method also includes a step in which the ambient IoT device determines an access method to the reader device based on the device identification information. The communication method also includes a step in which the ambient IoT device transmits a Device-to-Reader (D2R) message to the reader device in accordance with the access method.

[0011] A communication method according to a second aspect is a communication method for use in a mobile communication system, the communication method including a step of receiving, by an ambient IoT device, an R2D message including device identification information that identifies the ambient IoT device and D2R access method information that indicates an access method from a leader device that is a network node or user equipment of the mobile communication system, and a step of transmitting, by the ambient IoT device, the D2R message to the leader device in accordance with the access method.

[0012] A communication method according to a third aspect is a communication method for use in a mobile communication system. The communication method includes a step of receiving, by an ambient IoT device, an R2D message including device identification information identifying the ambient IoT device from a reader device. The communication method also includes a step of the ambient IoT device determining an access method. The communication method further includes a step of the ambient IoT device generating a transmission format identifier indicating the access method. The communication method also includes a step of the ambient IoT device transmitting, by the ambient IoT device, a D2R message including the transmission format identifier to the reader device in accordance with the access method.

[0013] FIG. 1 is a diagram showing an example of the configuration of a mobile communication system according to the first embodiment. FIG. 2 is a diagram showing an example of the configuration of a UE (user equipment) according to the first embodiment. FIG. 3 is a diagram showing an example of the configuration of a network node (gNB) according to the first embodiment. FIG. 4 is a diagram showing an example of the configuration of a protocol stack according to the first embodiment. FIG. 5 is a diagram showing an example of the configuration of a protocol stack according to the first embodiment. FIG. 6 is a diagram showing an example of the configuration of an ambient IoT device according to the first embodiment. FIGS. 7(A) and 7(B) are diagrams showing an example of a topology of an ambient IoT device according to the first embodiment. FIG. 8 is a diagram showing an example of the configuration of an ambient IoT device according to the first embodiment. FIG. 9 is a diagram showing an example of the configuration of an ambient IoT device according to the first embodiment. FIG. 10 is a diagram showing an example of the configuration of a protocol stack for an ambient IoT device according to the first embodiment. FIG. 11 is a diagram showing an example of a basic procedure according to the first embodiment. FIG. 12 is a diagram showing an example of a basic procedure according to the first embodiment. FIG. 13 is a diagram showing an example of an operation according to the first embodiment. FIG. 14 is a diagram showing an example of an operation according to the second embodiment. FIG. 15 is a diagram showing an example of an operation according to the third embodiment. FIG. 16 is a diagram showing an example of time slots and frequency channels.

[0014] A mobile communication system according to an embodiment will be described with reference to the drawings. In the description of the drawings, the same or similar parts are denoted by the same or similar reference numerals.

[0015] [First embodiment]

[0016] (1) Configuration of the Mobile Communication System The configuration of the mobile communication system according to the first embodiment will be described. FIG. 1 is a diagram showing an example of the configuration of the mobile communication system 1 according to the first embodiment. The mobile communication system 1 conforms to the 5th Generation System (5GS) of the 3GPP standard. Although the following description will be given using 5GS as an example, the mobile communication system may also be at least partially applied to an LTE (Long Term Evolution) system. The mobile communication system may also be at least partially applied to a sixth generation (6G) system or later system.

[0017] The mobile communication system 1 includes a network (NW) 10 and a user equipment (UE) 100. The UE 100 is a mobile communication device that performs wireless communication with the NW 10. The UE 100 may be any device used by a user, and may be, for example, a mobile phone terminal (including a smartphone) and / or a tablet terminal, a notebook PC (Personal Computer), a communication module (including a communication card or chipset), a sensor or a device provided in a sensor, a vehicle or a device provided in a vehicle (Vehicle UE), or an aircraft or a device provided in an aircraft (Aerial UE).

[0018] The NW 10 includes a radio access network (RAN) 20 and a core network (CN) 30. When the mobile communication system is a 5th generation system (5GS), the RAN 20 is referred to as a Next Generation Radio Access Network (NG-RAN), and the CN 30 is referred to as a 5G Core Network (5GC).

[0019] The RAN 20 includes a plurality of network nodes 200 (network nodes 200a to 200c in the example of FIG. 1). The network nodes 200 are connected to each other via inter-network node interfaces. The network nodes 200 may be referred to as base stations in the RAN 20. When the network node 200 is a base station, the network node 200 may be configured (i.e., functionally divided) with a CU (Central Unit) and a DU (Distribution Unit), and the two units may be connected by a fronthaul interface. When the mobile communication system 1 is 5GS, the network node 200 is referred to as a gNB, the inter-network node interface is referred to as an Xn interface, and the fronthaul interface is referred to as an F1 interface.

[0020] When at least a part of the mobile communication system 1 is an LTE system, the network node 200 may be an evolved Node B (eNB) that is an LTE base station. When the mobile communication system 1 is a sixth-generation system or later, the network node 200 has a function of a base station and may be a device equivalent to a gNB or an eNB.

[0021] Each network node 200 manages one or more cells. The network node 200 performs wireless communication with the UE 100 that has established a connection with the network node 200's cell. Each network node 200 has a radio resource management (RRM) function, a user data (also simply referred to as "data") routing function, a measurement control function for mobility control and scheduling, and the like. The term "cell" is used as a term indicating the smallest unit of a wireless communication area. The term "cell" is also used as a term indicating a function or resource for performing wireless communication with the UE 100. One cell belongs to one carrier frequency. One downlink component carrier and one uplink component carrier may be associated with one cell. The bandwidth (system bandwidth) corresponding to one cell may be divided into multiple band parts (BWP: Bandwidth Parts). In the following, a gNB may be used as an example of the network node 200.

[0022] The CN 30 includes a CN (Core Network) device 380. The CN device 380 may include a C-plane device corresponding to the control plane (C-plane) and a U-plane device corresponding to the user plane (U-plane). The C-plane device performs various mobility controls and paging for the UE 100. The C-plane device communicates with the UE 100 using NAS (Non-Access Stratum) signaling. The U-plane device controls data forwarding. When the mobile communication system is 5GS, the C-plane device is referred to as an AMF (Access and Mobility Management Function), the U-plane device is referred to as a UPF (User Plane Function), and the interface between the network node 200 and the CN device 380 is referred to as an NG interface.

[0023] 2 is a diagram illustrating an example of the configuration of a UE 100 (user equipment) according to the first embodiment. The UE 100 includes a receiving unit 110, a transmitting unit 120, and a control unit 130. The receiving unit 110 and the transmitting unit 120 configure a wireless communication unit 140 that performs wireless communication with a network node 200.

[0024] The receiving unit 110 performs various types of reception under the control of the control unit 130. The receiving unit 110 includes an antenna and a receiver. The receiver converts a radio signal received by the antenna into a baseband signal (received signal) and outputs the baseband signal to the control unit 130.

[0025] The transmitting unit 120 performs various transmissions under the control of the control unit 130. The transmitting unit 120 includes an antenna and a transmitter. The transmitter converts a baseband signal (transmission signal) output by the control unit 130 into a radio signal and transmits it from the antenna.

[0026] The control unit 130 performs various controls and processes in the UE 100. Such processes include processes of each layer described below. The operations of the UE 100 described above and below may be operations controlled by the control unit 230. The control unit 130 includes at least one processor and at least one memory. The memory stores programs executed by the processor and information used in the processing by the processor. The processor may include a baseband processor and a CPU (Central Processing Unit). The baseband processor performs modulation / demodulation and encoding / decoding of baseband signals. The CPU executes programs stored in the memory to perform various processes.

[0027] 3 is a diagram showing an example of the configuration of the network node 200 (gNB) according to the first embodiment. The network node 200 has a transmitting unit 210, a receiving unit 220, a control unit 230, and a network communication unit 240. The transmitting unit 210 and the receiving unit 220 constitute a wireless communication unit 250 that performs wireless communication with the UE 100.

[0028] The transmitting unit 210 performs various transmissions under the control of the control unit 230. The transmitting unit 210 includes an antenna and a transmitter. The transmitter converts a baseband signal (transmission signal) output by the control unit 230 into a radio signal and transmits it from the antenna.

[0029] The receiving unit 220 performs various types of reception under the control of the control unit 230. The receiving unit 220 includes an antenna and a receiver. The receiver converts a radio signal received by the antenna into a baseband signal (received signal) and outputs the baseband signal to the control unit 230.

[0030] The control unit 230 performs various controls and processes in the network node 200. Such processes include processes of each layer described below. The operations of the network node 200 described above and below may be operations under the control of the control unit 230. The control unit 230 includes at least one processor and at least one memory. The memory stores programs executed by the processor and information used in the processing by the processor. The processor may include a baseband processor and a CPU. The baseband processor performs modulation / demodulation and encoding / decoding of baseband signals. The CPU executes programs stored in the memory to perform various processes.

[0031] The network communication unit 240 is connected to adjacent base stations via an Xn interface, which is an interface between base stations. The network communication unit 240 is connected to the CN device 380 via an NG interface, which is an interface between a base station and a core network. Note that the network node 200 may be configured (i.e., functionally divided) with a CU (Central Unit) and a DU (Distributed Unit), and both units may be connected via an F1 interface, which is a fronthaul interface.

[0032] FIG. 4 is a diagram showing the configuration of a protocol stack of a radio interface of a user plane that handles data.

[0033] The user plane radio interface protocol includes a physical (PHY) layer, a medium access control (MAC) layer, a radio link control (RLC) layer, a packet data convergence protocol (PDCP) layer, and a service data adaptation protocol (SDAP) layer.

[0034] The PHY layer performs encoding / decoding, modulation / demodulation, antenna mapping / demapping, and resource mapping / demapping. Data and control information are transmitted between the PHY layer of the UE 100 and the PHY layer of the network node 200 via a physical channel. The PHY layer of the UE 100 receives downlink control information (DCI) transmitted on a physical downlink control channel (PDCCH) from the network node 200. Specifically, the UE 100 performs blind decoding of the PDCCH using a radio network temporary identifier (RNTI) and acquires successfully decoded DCI as DCI addressed to the UE. The DCI transmitted from the network node 200 has a CRC (Cyclic Redundancy Code) parity bit scrambled by the RNTI added.

[0035] The MAC layer performs data priority control, retransmission processing using Hybrid Automatic Repeat reQuest (HARQ), random access procedures, etc. Data and control information are transmitted between the MAC layer of the UE 100 and the MAC layer of the network node 200 via a transport channel. The MAC layer of the network node 200 includes a scheduler. The scheduler determines the uplink and downlink transport format (transport block size, modulation and coding scheme (MCS)) and the resource blocks to be allocated to the UE 100.

[0036] The RLC layer transmits data to the RLC layer on the receiving side using the functions of the MAC layer and the PHY layer. Data and control information are transmitted between the RLC layer of the UE 100 and the RLC layer of the network node 200 via logical channels.

[0037] The PDCP layer performs header compression / decompression, encryption / decryption, and the like.

[0038] The SDAP layer maps IP flows, which are units for Quality of Service (QoS) control by the core network, to radio bearers, which are units for QoS control by the Access Stratum (AS). Note that if the RAN is connected to the EPC, SDAP may not be required.

[0039] FIG. 5 is a diagram showing the configuration of a protocol stack of a radio interface of a control plane that handles signaling (control signals).

[0040] The protocol stack of the radio interface of the control plane has an RRC (Radio Resource Control) layer and an NAS (Non-Access Stratum) layer instead of the SDAP layer shown in FIG.

[0041] RRC signaling for various settings is transmitted between the RRC layer of the UE 100 and the RRC layer of the network node 200. The RRC layer controls logical channels, transport channels, and physical channels in accordance with the establishment, re-establishment, and release of radio bearers. When there is a connection (RRC connection) between the RRC of the UE 100 and the RRC of the network node 200, the UE 100 is in an RRC connected state. When there is no connection (RRC connection) between the RRC of the UE 100 and the RRC of the network node 200, the UE 100 is in an RRC idle state. When the connection between the RRC of the UE 100 and the RRC of the network node 200 is suspended, the UE 100 is in an RRC inactive state.

[0042] The NAS layer (also simply referred to as "NAS") located above the RRC layer performs session management, mobility management, etc. NAS signaling is transmitted between the NAS layer of the UE 100 and the NAS layer of the CN device 380 (AMF). Note that the UE 100 also has an application layer in addition to the radio interface protocol. The layer below the NAS layer is referred to as the AS layer (also simply referred to as "AS").

[0043] (2) Ambient IoT Device The mobile communication system 1 according to the embodiment supports an ambient IoT device. Hereinafter, the ambient IoT device may be simply referred to as a "device."

[0044] (2.1) Overview of Ambient IoT Device Fig. 6 is a diagram showing an example of the configuration of an ambient IoT device 300 according to the first embodiment. The ambient IoT device 300 is a wireless communication device capable of wireless communication with a reader device that is the UE 100 or the network node 200. The ambient IoT device 300 may perform wireless communication within the frequency band of the mobile communication system 1.

[0045] The ambient IoT device 300 may transmit information within the ambient IoT device 300 by reflecting radio waves transmitted from a reader device (UE 100 or network node 200) and modulating the reflected waves. Generally, the technology of reflecting unmodulated radio waves and modulating the reflected waves to transmit information is called backscattering communication. The ambient IoT device 300 may have a backscattering communication function. The ambient IoT device 300 may be an information medium capable of reading information from or writing information to an internal memory using the backscattering communication function. In this case, the ambient IoT device 300 may receive transmitted radio waves on which information has been modulated and extract the information by demodulating the received radio waves.

[0046] The ambient IoT device 300 may be a battery-less IoT device. In this case, the ambient IoT device 300 converts the received radio waves into energy (specifically, power) and operates using the energy. The ambient IoT device 300 may use an energy source other than radio waves, for example, light, heat, magnetism, vibration, or sound, to convert energy. Generally, such energy conversion is called energy harvesting. A known method for energy harvesting may be used. In this way, the ambient IoT device 300 may have an energy harvesting function. Alternatively, the ambient IoT device 300 may have a limited battery function. The ambient IoT device 300 may have a battery function for charging the power obtained by the energy harvesting function. The ambient IoT device 300 may be a wireless tag.

[0047] As shown in FIG. 6 , the ambient IoT device 300 includes an antenna 310 , a modulator 320 , a control unit 330 , and a memory 340 .

[0048] The antenna 310 receives an unmodulated carrier wave. Hereinafter, this unmodulated carrier wave will be referred to as a CW (Continuous Wave). The antenna 310 converts the received CW into a received signal and outputs this received signal to the modulator 320. The antenna 310 also reflects the CW in accordance with the transmission signal output from the modulator 320 and transmits a reflected wave. Hereinafter, this reflected wave will be referred to as a BS (Back Scattering or Back Scatter). The antenna 310 performs BS transmission.

[0049] The modulator 320 may generate a transmission signal by modulating data read from the memory 340 under the control of the control unit 330. The modulator 320 outputs the modulated signal to the antenna 310. Furthermore, the modulator 320 may acquire data by demodulating a signal received from the antenna 310 under the control of the control unit 330. The modulator 320 outputs the acquired data to the control unit 330. In the ambient IoT device 300, the modulator 320 may specifically be a switch. When the switch receives a reception signal from the antenna 310, the switch turns on and outputs the reception signal to the control unit 330. Furthermore, the switch is controlled to be on or off under the control of the control unit 330, and outputs a transmission signal corresponding to the on or off state to the antenna 310. The switch may be an RF (Radio Frequency) switch. The switch may be configured with a transistor. Alternatively, the switch may be a mechanical switch that can be physically switched on or off.

[0050] The control unit 330 may have an energy harvesting function that converts the received signal received from the modulator 320 into power. The control unit 330 may control the modulator 320 and the memory 340 using the power as driving power for the ambient IoT device 300. The control unit 330 may also read information stored in the memory 340 and control the modulator 320 to transmit a transmission signal corresponding to the information. For example, the control unit 330 may control the reflectivity of the reflected wave (BS) (e.g., whether the reflectivity is 100% or 0%) by turning the modulator 320 on or off, and output a transmission signal corresponding to information (e.g., 1 bit) stored in the memory 340 from the modulator 320 to the antenna 310. For example, the control unit 330 may control the timing of turning the modulator 320 on or off, and output a transmission signal corresponding to multiple bits from the modulator 320 to the antenna 310. In this way, the control unit 330 may control the reflectivity of the reflected wave (BS) by controlling the on or off of the modulator 320, and transmit a modulated reflected wave corresponding to the information stored in the memory 340 from the antenna 310.

[0051] The memory 340 stores various types of information. The information stored in the memory 340 may be information acquired when the ambient IoT device 300 functions as a sensor. Alternatively, the information stored in the memory 340 may be information specific to the ambient IoT device 300 that has been stored in advance in the memory 340. The specific information may include, for example, identification information of the ambient IoT device 300 (or the group to which the ambient IoT device 300 belongs). The type of the identification information may be "Device ID," "Group ID," and / or "ALL." The memory 340 can read the stored information under the control of the control unit 330. Information may be written to the memory 340 under the control of the control unit 330. In this case, the control unit 330 (or the modulator 320) converts the received signal received from the antenna 310 into a baseband signal in a baseband band, reads information from the baseband signal, and writes the read information to the memory 340.

[0052] The ambient IoT device 300 may have a limited battery. As described above, "limited" means a battery that does not need to be manually replaced and / or charged. The ambient IoT device 300 may have the ability to generate signals by itself. In this case, the ambient IoT device 300 does not need to receive the CW signal or perform the BS transmission. That is, the ambient IoT device 300 transmits a transmission signal that it generates by itself via the antenna 310.

[0053] (2.2) Topology of Ambient IoT Device Fig. 7(A) and Fig. 7(B) are diagrams showing examples of the topology of the ambient IoT device 300. Fig. 7(A) shows an example of "Topology 1", and Fig. 7(B) shows an example of "Topology 2".

[0054] An apparatus that performs wireless communication with the ambient IoT device 300 is referred to as a reader apparatus (or "Reader") 400. As shown in FIG. 7A, in "Topology 1", the reader apparatus 400 is a network node 200 (gNB). The reader apparatus 400 may be a relay node, which is a type of network node. For example, the reader apparatus 400 may be an IAB (Integrated Access and Backhaul) node or an NCR (Network-Controlled Repeater). In "Topology 1", data related to the ambient IoT device 300 and / or signaling related to the ambient IoT device 300 are transferred between the ambient IoT device 300 and the network node 200.

[0055] 7A , the ambient IoT device 300 communicates directly and bidirectionally with the network node 200, which corresponds to the reader device 400. In this case, the wireless communication unit 250 (transmitter 210 and receiver 220) of the network node 200 is capable of wireless communication with the ambient IoT device 300. For example, the transmitter 210 of the network node 200 may transmit an unmodulated carrier wave under the control of the control unit 230. The carrier wave may be reflected by the ambient IoT device 300. The receiver 220 of the network node 200 may receive a reflected wave reflected by the ambient IoT device 300 under the control of the control unit 230, convert the reflected wave into a baseband signal, and output the baseband signal to the control unit 230.

[0056] 7(B), in "Topology 2", the reader device 400 is the UE 100. In this case, the UE 100 corresponds to an intermediate node between the ambient IoT device 300 and the network node 200. In "Topology 2", the ambient IoT device 300 performs bidirectional wireless communication with the UE 100. The reader device 400 transfers data related to the ambient IoT device 300 and / or signaling related to the ambient IoT device 300 between the network node 200 and the ambient IoT device 300.

[0057] In the example shown in FIG. 7B , the UE 100 performs wireless communication with the network node 200 over the Uu interface. The ambient IoT device 300 communicates directly and bidirectionally with the UE 100, which corresponds to the reader device 400. In this case, the wireless communication unit 140 (the receiver 110 and the transmitter 120) of the UE 100 can perform wireless communication with the ambient IoT device 300. For example, the receiver 110 of the UE 100 may receive a reflected wave reflected at the ambient IoT device 300 under the control of the control unit 130. The receiver 110 may receive the received reflected wave as a wireless signal, convert it into a baseband signal, and output it to the control unit 130. The transmitter 120 of the UE 100 may transmit an unmodulated carrier wave under the control of the control unit 130. The carrier wave may be reflected at the ambient IoT device 300.

[0058] (2.3) Detailed Configuration Example of Ambient IoT Device In 3GPP, it has been agreed that there are three types of ambient IoT device 300: "Device 1", "Device 2a", and "Device 2b".

[0059] "Device 1" is, for example, a device that has a peak power consumption of "1 μW" or less, does not perform amplification in either the DL or UL direction, and performs backscattering transmission using an externally provided carrier wave.

[0060] "Device 2a" is, for example, a device that has a peak power consumption of "several hundred μW" or less, performs amplification in the DL direction and / or UL direction, and performs backscattering transmission using an externally provided carrier wave.

[0061] "Device 2b" is, for example, a device with peak power consumption of "several hundred μW" or less, with amplification in the DL and / or UL directions, and with UL transmissions generated internally within the device. Note that both device types have energy storage capabilities.

[0062] FIG. 8 is a diagram illustrating an example of the configuration of an ambient IoT device 300, which is “device 1” according to the first embodiment.

[0063] "Device 1" includes an antenna 310, a matching network 350, an RF energy harvester 351, a power management unit (PMU) 352, an energy storage unit 353, an RF radio frequency band pass filter (RF BPF) 354, an RF envelope detector (or envelope detector) 355, a base band low pass filter (BB LPF) 356, a comparator 357, baseband logic 358, a memory 359, a backscattering modulator 360, and a clock generator 361.

[0064] The matching network 350 matches the impedance between the antenna 310 and other blocks (including the RF energy harvester 351 and the RF BPF 354), and outputs the radio signal received by the antenna 310 to the other blocks.

[0065] The RF energy harvester 351 has an energy harvesting function and extracts energy from the radio signal. The RF energy harvester 351 may also include a rectifier that converts the radio signal from an AC component to a DC component.

[0066] The PMU 352 manages (or controls) the accumulation of energy from the RF energy harvester 351 and manages (or controls) the supply of power to the blocks that require it.

[0067] The energy storage unit 353 stores energy from the RF energy harvester 351 .

[0068] The RF BPF 354 outputs a radio signal in a specific frequency band. The RF BPF 354 is used to improve selectivity. Note that the RF BPF 354 may not be included in the "device 1" depending on the implementation.

[0069] The RF envelope detector 355 converts the radio signal in the radio band output from the RF BPF 354 into a baseband signal in the baseband band.

[0070] The BB LPF 356 removes high frequency components from the baseband signal output from the RF envelope detector 355 and improves the quality of the signal input to the comparator 357 .

[0071] The comparator 357 determines whether the input signal output from the BB LPF 356 is "high" or "low." Note that the comparator 357 is not limited to detecting two values, "high" and "low," and may detect three or more values.

[0072] The baseband logic 358 includes functional blocks such as an encoder, a decoder, and a controller.

[0073] Memory 359 stores device identification information (or device ID) and the like for identifying (or distinguishing) ambient IoT device 300 from other ambient IoT devices. Memory 359 may be a non-volatile memory (for example, an EEPROM (Electrically Erasable Programmable Read-Only Memory)) that permanently stores the device ID and the like. Memory 359 may also be a memory (register) that temporarily stores information required only while the energy stored in energy storage unit 353 is available.

[0074] The backscattering modulator 360 switches impedance to modulate the output signal from the baseband logic 358 into a backscattering signal. Alternatively, the backscattering modulator 360 switches impedance (the impedance of the antenna or the transmission line) using the output signal (digital signal or digital data) from the baseband logic 358 to modulate the high-frequency signal (e.g., CW) input from the antenna 310 into a backscattering signal. For example, the backscattering modulator 360 can modulate and then reflect the high-frequency signal input from the antenna 310 by terminating (not reflecting) the high-frequency input signal for digital data "0" and opening (reflecting) the high-frequency input signal for digital data "1."

[0075] The clock generator 361 generates the clock signals required within the device.

[0076] The above is an example of the configuration of "device 1." The matching network 350, RF BPF 354, RF envelope detector 355, BB LPF 356, comparator 357, and backscattering modulator 360 may be included in the modulator 320 shown in FIG. 6. The PMU 352 and baseband logic 358 may be included in the control unit 330 shown in FIG. 6. Furthermore, the memory 359 may correspond to the memory 340 shown in FIG. 6.

[0077] FIG. 9 is a diagram illustrating an example of the configuration of an ambient IoT device 300 of the “device 2 a ” according to the first embodiment.

[0078] The "device 2a" further includes an LNA (Low Noise Amplifier) ​​365, a baseband amplifier 366, a large frequency shifter 367, a reflection amplifier 368, and an energy harvester 369 in addition to the components of the "device 1" shown in FIG.

[0079] The LNA 365 amplifies the output signal from the RF BPF 354 (i.e., the signal from the reader device (network node 200 or UE 100)) to improve the signal strength and signal sensitivity at the receiving side.

[0080] The baseband amplifier 366 amplifies the baseband signal output from the RF envelope detector 355 to improve the signal strength.

[0081] The large frequency shifter 367 shifts the frequency of the backscattering signal from one frequency (eg, the FDD-DL frequency) to another frequency (eg, the FDD-UL frequency).

[0082] The energy harvester 369 generates energy from an environment using a source other than an RF signal. Specifically, energy harvesting sources include sunlight (solar panels), vibration (vibration power generation), and heat (thermal power generation), but are not limited to these.

[0083] The above has described a configuration example of the "device 2a." In the block configuration example shown in Fig. 9, in relation to the block configuration example shown in Fig. 6, the modulator 320 may further include an LNA 365, a baseband amplifier 366, a large frequency shifter 367, and a reflection amplifier 368.

[0084] (2.4) Protocol Stack for Ambient IoT Device FIG. 10 is a diagram showing an example of the configuration of a protocol stack for the ambient IoT device 300 according to the first embodiment.

[0085] The air interface protocol includes a PHY layer and an ambient IoT (A-IoT) MAC layer. A new layer (New AS Protocol) may be introduced as an upper layer of the A-IoT MAC layer. Communication between a reader device 400 (described later) and an ambient IoT device 300 may be performed by at least one of the layers shown in FIG. 10 .

[0086] The physical channel used for transmission from the reader device 400 to the ambient IoT device 300 (hereinafter, sometimes referred to as "R2D (Reader-to-Device) transmission") is called a PRDCH (Physical Reader to Device channel). A channel used for R2D transmission is also referred to as an R2D channel. The R2D channel may be a PRDCH. A message transmitted using the R2D channel is called an R2D message. The R2D message may be a message specified in "A-IoT MAC" or "New AS Protocol."

[0087] On the other hand, the physical channel used for transmission from the ambient IoT device 300 to the reader device 400 (hereinafter, sometimes referred to as "Device to Reader (D2R) transmission") is called a Physical Device to Reader channel (PDRCH). The channel used for D2R transmission is also called a D2R channel. The D2R channel may be a PDRCH. A message transmitted using the D2R channel is called a D2R message. The D2R message may also be a message specified in "A-IoT MAC" or "New AS Protocol".

[0088] For example, in "Topology 1", the physical channel used for R2D transmission from the network node 200 to the ambient IoT device 300 is PRDCH, and the physical channel used for D2R transmission from the ambient IoT device 300 to the network node 200 is PDRCH. Also in "Topology 2", the physical channel used for R2D transmission from the UE 100 to the ambient IoT device 300 is PRDCH, and the physical channel used for D2R transmission from the ambient IoT device 300 to the UE 100 is PDRCH.

[0089] It should be noted that the control plane between the reader device 400 and the ambient IoT device 300 does not have an RRC layer between the reader device 400 and the ambient IoT device 300, and does not support RRC connection management, Layer 3 (L3) measurement reporting, periodic system information, and Master Information Block (MIB). Also, the ambient IoT device 300 does not support traditional paging messages.

[0090] The SDAP layer, the PDCP layer, and the RLC layer are not present in the user plane between the reader device 400 and the ambient IoT device 300. In addition, the AS layer above the PHY layer does not support HARQ and RLC AM (Acknowledge Mode).

[0091] (3) Operation of the Mobile Communication System The operation of the mobile communication system 1 having the ambient IoT device 300 will be described.

[0092] (3.1) Basic Procedures Fig. 11 is a diagram illustrating an example of basic procedures in the mobile communication system 1 according to the first embodiment. As shown in Fig. 11, one of the basic procedures is "Inventory only." "Inventory only" is used, for example, in a use case in which presence confirmation is performed on the ambient IoT device 300.

[0093] Furthermore, one of the basic procedures is “Command only.” “Command only” is used in a use case in which various commands, such as read, write, or kill, are issued to the ambient IoT device 300.

[0094] Furthermore, one of the basic procedures is “Inventory and Command.” “Inventory and Command” is used in a use case in which, for example, the presence of the ambient IoT device 300 is confirmed and various commands are issued to the ambient IoT device 300.

[0095] 11 , in either case, a paging message for ambient IoT (A-IoT paging message) similar to a conventional paging message is transmitted from the reader device 400 to the ambient IoT device 300 (step S1). The A-IoT paging message may be a message for initiating communication between the reader device 400 and the ambient IoT device 300. Alternatively, the A-IoT paging message may be a call message (or a trigger message) for calling (or triggering) the ambient IoT device 300.

[0096] First, the A-IoT paging message includes device identification information that identifies the ambient IoT device. The device identification information may be used to specify the ambient IoT device to be called. Types of device identification information include a "device ID" (individual identification information) that individually identifies each ambient IoT device 300. Types of device identification information include a "group ID" (group identification information) that identifies the group to which the ambient IoT device belongs. Types of device identification information include "ALL" (all identification information) that indicates all ambient IoT devices. However, if the A-IoT paging message does not include device identification information, it will represent "ALL".

[0097] Second, the A-IoT paging message includes resource information, which is used to transmit a D2R message from the ambient IoT device 300 to the reader device 400.

[0098] Third, the A-IoT paging message may be an initial trigger message. The initial trigger message is, for example, a message including an ambient IoT device that needs to respond to a service request. The service request is received by the leader device 400 from the network 5 (the network node 200 or the CN device 380). For example, the service request includes device identification information of the ambient IoT device 300. The leader device 400 uses the initial trigger message to make a call to the ambient IoT device 300 that has the device identification information.

[0099] In the case of "command only", the A-IoT paging message includes an R2D command. The R2D command allows the reader device 400 to issue various commands to the ambient IoT device 300.

[0100] Step B: In either case, the ambient IoT device 300 transmits its device ID (step S2). For example, the ambient IoT device 300 triggered by an A-IoT paging message transmits its own device ID in this step. The device ID transmission may be performed using a D2R message. The reader device 400 receives the device ID.

[0101] Here, the transmission of the device ID may be performed by an access method similar to random access (RA). This access method is hereinafter referred to as a random access procedure (or an access method using "random access"). In the random access procedure, contention resolution is performed to avoid contention in the transmission of D2R messages. Details of the random access procedure will be described later.

[0102] On the other hand, there are also cases where the device ID is transmitted using a contention-free access method without performing contention resolution. This access method is called a contention-free access procedure (or an access method using "contention-free access"). In the contention-free procedure, the random access procedure is not performed. Operation examples of the random access procedure and the contention-free procedure will be described later.

[0103] Step C1 and Step C2: Step C1 and Step C2 are not performed in the "inventory only" case, but are performed in the "inventory and command" and "command only" cases. In Step C1, the reader device 400 transmits R2D data (Step S3), and in Step C2, the ambient IoT device 300 transmits D2R data (Step S4). For example, the reader device 400 transmits an R2D command (Step C1), and the ambient IoT device 300 transmits feedback for the R2D command to the reader device 400 (Step C2).

[0104] In the case of "inventory and command," both "inventory" and "command" are not performed using a single A-IoT paging message, but rather "inventory" and "command" are performed using separate messages.

[0105] (3.2) Random Access and Contention-Free Access Figure 12 is a diagram showing examples of a random access procedure and a contention-free access procedure according to the first embodiment. Figure 12 shows the procedure performed in step B of Figure 11. As shown in Figure 12, there are two random access procedures: "four-step random access" and "two-step random access." Therefore, there are three access methods performed in step B of Figure 11: "four-step random access," "two-step random access," and "contention-free access." As shown in Figure 12, "four-step random access" is actually completed in three steps, so it may also be called "three-step random access."

[0106] Step 1: In all three procedures, first, the ambient IoT device 300 determines and / or selects a resource (or access opportunity) (step S10).

[0107] Step 2: Step 2 is executed in the case of a random access procedure, but is not executed in the case of a contention-free access procedure. In Step 2, contention resolution is performed.

[0108] In the case of "four-step random access," the ambient IoT device 300 transmits a random ID in message 1 (Msg1) (step S11). The random ID is random identification information generated by the ambient IoT device 300. Msg1 may be a D2R message.

[0109] The reader device 400 transmits the random ID received from the ambient IoT device 300 to the ambient IoT device 300 in a message 2 (Msg2) (step S12). Msg2 may be an R2D message.

[0110] If the random ID transmitted in Msg1 matches the random ID received in Msg2, the ambient IoT device 300 considers the contention resolution to be successful (OK) (step S13). In other words, since the ambient IoT device 300 was able to receive the random ID transmitted in Msg1 in Msg2, it can be determined that the resources used to transmit Msg1 do not conflict with the resources used to transmit Msg1 from other ambient IoT devices. On the other hand, if the two random IDs do not match, the ambient IoT device 300 considers the contention resolution to have failed. In this case, the ambient IoT device 300 cannot receive the random ID transmitted in Msg1 in Msg2, so it can determine that the resource used to transmit Msg1 conflicts with the resource used to transmit Msg1 from another ambient IoT device, and can regard the conflict resolution as having failed. Conflict resolution is also a procedure for determining whether or not the resource used to transmit the D2R message (specifically, Msg1) conflicts.

[0111] On the other hand, in the case of "two-step random access", the ambient IoT device 300 transmits the upper layer data to the reader device 400 using Msg1 (step S20). The upper layer data may include the device ID of the ambient IoT device 300.

[0112] The reader device 400 uses Msg2 to transmit some information (echo) to the ambient IoT device 300. Currently, 3GPP has not determined what information should be transmitted as the echo.

[0113] If the upper layer data transmitted in Msg1 (step S20) matches some information received in Msg2 (step S22), the ambient IoT device 300 determines that the conflict resolution is successful (step S23). If the upper layer data does not match some information, the ambient IoT device 300 determines that the conflict resolution is unsuccessful.

[0114] Step 3: In the case of a random access procedure, the ambient IoT device 300 that has successfully resolved the contention transmits upper layer data to the leader device 400 (steps S14 and S24). The upper layer data may include the device ID of the ambient IoT device 300. The upper layer data may be transmitted in a D2R message.

[0115] On the other hand, in the case of "contention-free access," the ambient IoT device 300 transmits upper layer data to the leader device 400 without performing a random access procedure (step S30).

[0116] In this way, D2R transmission performed after contention resolution can be considered to be a "random access procedure," and D2R transmission performed without contention resolution can be considered to be a "contention-free access procedure." Furthermore, regarding the "random access procedure," contention resolution using random identification information can be considered to be a "four-step random access procedure," and contention resolution using higher layer data can be considered to be a "two-step random access procedure."

[0117] (4) Communication Method According to the First Embodiment As described above, in each of the cases of "Inventory Only," "Inventory and Command," and "Command Only," the ambient IoT device 300 transmits a device ID (step B, step S2). At this time, the ambient IoT device 300 transmits the device ID (step B, step S2 in FIG. 11 ) using one of three procedures (access methods).

[0118] However, at present, it is not clear how each of the three procedures is identified. If a procedure is executed without being identified, it may not be possible to properly communicate between the reader device 400 and the ambient IoT device 300.

[0119] Therefore, the first embodiment aims to enable appropriate communication between a reader device and an ambient IoT device.

[0120] Therefore, in the first embodiment, the ambient IoT device 300 identifies a procedure based on device identification information included in the A-IoT paging message. Specifically, first, the ambient IoT device (e.g., the ambient IoT device 300) receives an R2D message including device identification information that identifies the ambient IoT device from a reader device (e.g., the reader device 400). Second, the ambient IoT device determines a method for accessing the reader device based on the device identification information. Third, the ambient IoT device transmits a D2R message to the reader device in accordance with the access method.

[0121] In this way, the ambient IoT device 300 determines the access method (or procedure) based on the device identification information, making it possible to clearly identify the access method. Furthermore, the ambient IoT device 300 and the reader device 400 can identify the access method for D2R transmission based on the device identification information, and can share the access method. Therefore, appropriate communication can be performed between the reader device 400 and the ambient IoT device 300.

[0122] (5) Operation Example According to First Embodiment Next, an operation example according to the first embodiment will be described.

[0123] FIG. 13 is a diagram illustrating an example of operation according to the first embodiment.

[0124] As shown in FIG. 13 , in step S40, the receiving unit of the reader device 400 (the receiving unit 110 of the UE 100 or the NW communication unit 240 of the network node 200) receives a service request from the network 5. The service request includes device identification information of the ambient IoT device 300 to be called (or triggered). As described above, the type of device identification information is one of "device ID," "group ID," and "ALL." Also, as described above, if the service request does not include device identification information, it means "ALL."

[0125] Note that, when the leader device 400 is the network node 200, the service request may be included in a message transmitted from the CN device 380 to the network node 200, for example, an NG-AP (Application Protocol) message. Alternatively, when the leader device 400 is the UE 100, the service request may be included in a message transmitted from the network node 200 to the UE 100, for example, an RRC message. The service request may be included in a message of a layer newly defined for the ambient IoT device 300. Alternatively, the service request may be received from an upper layer (for example, an application layer). The upper layer may be present in the leader device 400. That is, the radio protocol unit of the leader device 400 may receive the service request from its own application layer.

[0126] In step S41, the control unit of the reader device 400 (the control unit 130 of the UE 100 or the control unit 230 of the network node 200) selects device identification information to be included in the A-IoT paging message based on the device identification information included in the service request. Basically, the reader device 400 selects the type of device identification information according to the type of device identification information included in the service request.

[0127] First, the reader device 400 may select a "device ID" that allows orthogonal access (i.e., collision-free access) in consideration of resources used for D2R transmission. When a "device ID" is included in a service request, the reader device 400 selects the "device ID" as device identification information, but may also select a "device ID" in consideration of resources.

[0128] For example, if there are resources for two ambient IoT devices 300 as orthogonally accessible D2R transmission resources, and a service request instructs the calling of two ambient IoT devices 300, the reader device 400 selects a "device ID" as device identification information. On the other hand, for device IDs for which orthogonal access is not possible, the reader device 400 may include the device ID in the next A-IoT paging message and transmit it. For example, assume that there are resources for two ambient IoT devices 300 as orthogonally accessible D2R transmission resources, and a service request instructs the calling of four ambient IoT devices 300. In such a case, the reader device 400 may select two device IDs for the current A-IoT paging message and the next A-IoT paging message, respectively.

[0129] Second, the reader device 400 may select a “group ID” and / or “ALL” to perform non-orthogonal access (i.e., collision-based access). If a “group ID” is included in the service request, the reader device 400 may select the “group ID” as the device identification information. If the service request includes “ALL” (or if there is no device identification information), the reader device 400 may select “ALL” as the device identification information. In the case of “device ID,” the reader device 400 can determine the number of ambient IoT devices 300 performing D2R transmission, and therefore can allocate resources that allow orthogonal access. On the other hand, in the case of “group ID” or “ALL,” the reader device 400 cannot determine the number of ambient IoT devices 300 performing D2R transmission, and it is assumed that they will respond to the trigger all at once, which may result in non-orthogonal access. The leader device 400 may select "Group ID" and / or "ALL" assuming non-orthogonal access.

[0130] In step S42, the transmitter of the leader device 400 (the transmitter 120 of the UE 100 or the transmitter 210 of the network node 200) transmits an A-IoT paging message including the device identification information selected in step S41. Step S42 is an operation corresponding to step A (or step 1) of the basic procedure (FIG. 11). The A-IoT paging message may include resource information used for D2R transmission. The ambient IoT device 300 receives the A-IoT paging message.

[0131] In step S43, the control unit 330 of the ambient IoT device 300 compares the device identification information included in the A-IoT paging message with its own device identification information to confirm whether they match. If they match, the ambient IoT device 300 determines an access method and / or resources (D2R transmission resources) to the reader device 400 based on the type of device identification information included in the A-IoT paging message.

[0132] First, if the type of the device identification information is "device ID," the ambient IoT device 300 selects a contention-free access method (or a contention-free access procedure) as the access method. In this case, the ambient IoT device 300 generates a D2R message including upper layer data and transmits the D2R message to the reader device without performing a random access procedure.

[0133] Second, when the type of device identification information is "group ID," the ambient IoT device 300 selects "random access," which performs contention resolution, as the access method. When the type of device identification information is "group ID," it is assumed that D2R transmission will be non-orthogonal access, and therefore contention resolution can be achieved by the "random access procedure."

[0134] Specifically, the ambient IoT device 300 may select "four-step random access." In this case, the ambient IoT device 300 generates a random ID and transmits a D2R message including the random ID to the leader device. Alternatively, if the type of device identification information is "group ID," the ambient IoT device 300 may select "two-step random access" as the access method. In this case, the ambient IoT device 300 transmits a D2R message including upper layer data (e.g., "device ID") to the leader device.

[0135] Third, if the type of device identification information is "ALL," the ambient IoT device 300 selects "random access," which performs contention resolution, as the access method. In this case, too, it is expected that the D2R transmission will be non-orthogonal access, so contention resolution can be achieved by the "random access procedure."

[0136] Specifically, the ambient IoT device 300 may select "four-step random access." The ambient IoT device 300 may select "two-step random access." If the ambient IoT device 300 selects "four-step random access," it transmits a D2R message including a random ID, and if it selects "two-step random access," it transmits a D2R message including upper layer data to the reader device 400. The same applies when the A-IoT paging message does not include device identification information.

[0137] In addition, the ambient IoT device 300 may select "two-step random access" if the type of device identification information is "group ID", and may select "four-step random access" if the type of device identification information is "ALL" (or if there is no device identification information).

[0138] In the case of "group ID," the number of ambient IoT devices 300 to be called is expected to be smaller than in "ALL," and the collision probability is also expected to be lower than in "ALL." Furthermore, in "two-step random access," the amount of information of the upper layer data transmitted by Msg1 is expected to be greater than that of the random ID transmitted by Msg1 in "four-step random access." This is because, for ambient IoT devices 300, it is better to select "two-step random access," which can transmit a larger amount of information, if the collision probability is lower.

[0139] On the other hand, in the case of "ALL," the number of ambient IoT devices 300 to be called is unknown, and the number of ambient IoT devices 300 accessed by random access will be greater than with "Group ID," so it can be assumed that the collision probability will be higher compared to "Group ID." This is because, for ambient IoT devices 300, if the collision probability is high, it is better to select "4-step random access," which can transmit a smaller amount of information in Msg1 than "2-step random access."

[0140] Selecting the contention-free access method as the access method may be selecting radio resources allocated for contention-free access (D2R transmission resources).

[0141] Furthermore, selecting the random access method as the access method may be selecting radio resources allocated for random access (D2R transmission resources).

[0142] Furthermore, selecting the four-step random access method or the two-step random access method as the access method may mean selecting radio resources (D2R transmission resources) allocated for four-step random access or two-step random access, respectively.

[0143] Furthermore, information on each of the radio resources (D2R transmission resources) may be notified in step S42 or may be set in advance (configuration or pre-configuration) in the ambient IoT device 300. The information on the radio resources may include information for identifying one or more of the radio resources, such as a frequency (channel) and a time (time slot), and a use (contention-free access, random access, four-step random access, two-step random access) assigned to the radio resources or assigned identification information (device ID, group ID, ALL).

[0144] The ambient IoT device 300 performs D2R transmission (Step 3 in FIG. 12) using the selected access method. Note that the ambient IoT device 300 performs backscattering transmission in the D2R transmission, and the CW used for the transmission may be the CW portion of the A-IoT paging message in step S42. Alternatively, the ambient IoT device 300 may use a CW transmitted from a reader device other than the reader device 400 that transmitted the A-IoT paging message. The same applies to the following description of D2R transmission.

[0145] In step S42, if the device identification information included in the A-IoT paging message does not match the ambient IoT device 300's own device identification information, the ambient IoT device 300 determines that the message is not a call (trigger) for the device itself and does not perform D2R transmission.

[0146] Second Embodiment Next, a second embodiment will be described, focusing on the differences from the first embodiment.

[0147] In the first embodiment, an example in which the access method for D2R transmission is specified based on the type of device identification information is described. In the second embodiment, an example in which the reader device 400 transmits D2R access method information indicating the access method for D2R transmission to the ambient IoT device 300 is described. Note that the access method may be "random access" or "contention-free access", the same as in the first embodiment. The access method may also be "four-step random access", "two-step random access", or "contention-free access".

[0148] Specifically, an ambient IoT device (e.g., ambient IoT device 300) receives an R2D message including device identification information that identifies the ambient IoT device and D2R access method information that indicates an access method from a reader device (e.g., reader device 400). Second, the ambient IoT device transmits a D2R message to the reader device according to the access method.

[0149] As described above, in the second embodiment, the reader device 400 transmits D2R access method information indicating the access method for D2R transmission to the ambient IoT device 300, so it becomes clear which access method (or procedure) to use for D2R transmission in the ambient IoT device 300. Therefore, in the second embodiment, as in the first embodiment, the reader device 400 and the ambient IoT device 300 share information about the access method to be used, enabling appropriate communication.

[0150] (Example of Operation According to Second Embodiment) Next, an example of operation according to the second embodiment will be described.

[0151] FIG. 14 is a diagram illustrating an example of operation according to the second embodiment.

[0152] 14, in step S50, the reader device 400 receives a service request. The process in step S50 is the same as step S40 (FIG. 11).

[0153] In step S51, the reader device 400 selects an access method for D2R transmission. The reader device 400 may select the access method based on device identification information included in the service request. Specifically, the reader device 400 may select the access method depending on the type of device identification information included in the service request.

[0154] First, when the type of device identification information included in the service request is "device ID," the reader device 400 may select "contention-free access" as the access method. As in the first embodiment, the reader device 400 may select an access method such that access from the ambient IoT device 300 is orthogonal access, taking into account the resources used for D2R transmission. For example, when the number of "device IDs" is equal to or greater than a threshold, "contention-free access" is expected to result in non-orthogonal access, so "random access" in which contention resolution is performed may be selected. Alternatively, as in the first embodiment, the reader device 400 may select "contention-free access" and transmit an A-IoT paging message multiple times, with each A-IoT paging message containing a different "device ID." When the reader device 400 selects "contention-free access" as the access method, it generates information bits (e.g., "00") indicating "contention-free access."

[0155] Second, when the type of device identification information included in the service request is "group ID" or "ALL" (or no device identification information is included), the reader device 400 may select "random access" as the access method. In this case, when the reader device 400 selects "random access" as the access method, it generates an information bit (e.g., "10") indicating "random access." Alternatively, when the type of device identification information included in the service request is "group ID," the reader device 400 may select "two-step random access," and when the type of device identification information included in the service request is "ALL" (or no device identification information is included in the service request), it may select "four-step random access." When the reader device 400 selects "four-step random access," it generates an information bit (e.g., "10") indicating "four-step random access." When the reader device 400 selects "two-step random access," it generates an information bit (e.g., "01") indicating "two-step random access."

[0156] Third, the reader device 400 may specify an information bit for each piece of device identification information to be called by one A-IoT paging message. Alternatively, the reader device 400 may specify the same information bit for all pieces of device identification information. The former is a method of specifying device identification information specific (ID-specific), and the latter is a method of specifying using a common information bit.

[0157] In step S52, the reader device 400 transmits an A-IoT paging message including D2R access method information. The D2R access method information includes information bits generated by the reader device 400. The information bits specify the access method. The ambient IoT device 300 receives the A-IoT paging message.

[0158] In step S53, the ambient IoT device 300 compares the device identification information included in the A-IoT paging message with its own device identification information to confirm whether they match. If they match, the ambient IoT device 300 determines the access method for D2R transmission according to the D2R access method information. The ambient IoT device 300 performs D2R transmission using the determined access method. On the other hand, if they do not match, the ambient IoT device 300 determines that the call (or trigger) is not its own call, and does not perform D2R transmission.

[0159] Third Embodiment Next, a third embodiment will be described, focusing on the differences between the first and second embodiments.

[0160] In the third embodiment, an example will be described in which the ambient IoT device 300 autonomously determines an access method. Specifically, first, the ambient IoT device (e.g., the ambient IoT device 300) receives an R2D message including device identification information that identifies the ambient IoT device from a reader device (e.g., the reader device 400). Second, the ambient IoT device determines the access method. Third, the ambient IoT device generates a transmission format identifier that indicates the access method. Fourth, the ambient IoT device transmits a D2R message including the transmission format identifier to the reader device in accordance with the access method.

[0161] As described above, in the third embodiment, information (transmission format identifier) ​​indicating the access method determined by the ambient IoT device 300 is transmitted to the reader device 400, so that the reader device 400 can grasp the access method for D2R transmission. Therefore, in the third embodiment as well, the method for determining the access method is clarified, and the access method to be used is shared between the reader device 400 and the ambient IoT device 300. Therefore, appropriate communication can be performed between the reader device 400 and the ambient IoT device 300.

[0162] (Example of Operation According to Third Embodiment) Next, an example of operation according to the third embodiment will be described.

[0163] FIG. 15 is a diagram illustrating an example of operation according to the third embodiment.

[0164] 15, in step S60, the reader device 400 transmits an A-IoT paging message. The A-IoT paging message includes device identification information of the ambient IoT device 300 to be called. The A-IoT paging message may include resource information used for D2R transmission. The A-IoT paging message may include the D2R access method information described in the second embodiment. The ambient IoT device 300 receives the A-IoT paging message.

[0165] In step S61, the ambient IoT device 300 compares the device identification information included in the A-IoT paging message with its own device identification information to confirm whether they match. If they match, the ambient IoT device 300 selects an access method to be used for D2R transmission. As in the first embodiment, the ambient IoT device 300 may determine the access method based on the device identification information included in the A-IoT paging message. Alternatively, as in the second embodiment, the ambient IoT device 300 may select the access method according to the D2R access method information included in the A-IoT paging message. Alternatively, the ambient IoT device 300 may select the access method based on the resource information included in the A-IoT paging message. For example, if resource #0 is a resource used for "random access" and resource #1 is a resource used for "contention-free access," the access method may be selected depending on whether the resource information is resource #0 or resource #1. Alternatively, the ambient IoT device 300 may follow the access method written in its own memory. In this case, it can be said that the ambient IoT device 300 autonomously selects the access method. Alternatively, the ambient IoT device 300 may monitor the surrounding environment and select an access method permitted by available wireless resources. For example, if resource #0 is an available wireless resource as a result of monitoring the surrounding environment, and resource #0 is a wireless resource used for "random access," "random access" is selected. In this case, it is also assumed that each resource is associated with an access method. In this case, it can also be said that the ambient IoT device 300 autonomously selects the access method. Note that if the device identification information included in the A-IoT paging message does not match its own device identification information, the ambient IoT device 300 determines that the call is not its own and does not perform R2D transmission.

[0166] In step S62, the ambient IoT device 300 generates a transmission format identifier indicating the access method selected in step S62. The transmission format identifier may represent the transmission format of the D2R message. For example, in the case of Msg1 (Step 2 in FIG. 12), random identification information is transmitted in "four-step random access" and upper layer data is transmitted in "two-step random access," and the formats are different for each. On the other hand, Msg1 is not transmitted in "collision-free access." The format identifier can be said to represent, for example, the transmission format of D2R transmission (Msg1 transmission or upper layer data transmission) as well as the access method of D2R transmission.

[0167] First, when ambient IoT device 300 selects "four-step random access" as the access method, it generates a format identifier (e.g., "001") representing "four-step random access" as the transmission format identifier, and when it selects "two-step random access", it generates a transmission format identifier (e.g., "010") representing "two-step random access". Furthermore, when ambient IoT device 300 selects "contention-free access" as the access method, it generates a transmission format identifier (e.g., "100") representing "contention-free access".

[0168] Second, the ambient IoT device 300 may generate different format identifiers depending on the content of the upper layer data. For example, if the upper layer data includes only a "device ID," the ambient IoT device 300 generates a transmission format identifier (e.g., "101") indicating that the upper layer data is a "device ID." Furthermore, if the upper layer data includes a "device ID" and "data," the ambient IoT device 300 generates a transmission format identifier (e.g., "110") indicating that the upper layer data includes a "device ID" and "data." Note that if the size of the "data" is equal to or greater than a certain size and the D2R message is segmented and transmitted, the last segmented D2R message (the last message of the segment) may include a transmission format identifier (e.g., "111"). This transmission format identifier can serve as an end marker. On the other hand, if the size of "data" is less than a certain value and the D2R message does not need to be segmented (i.e., segmentation is not required), the D2R message may include a transmission format identifier (e.g., "111"). The transmission format identifier is included in the last message if the D2R message is segmented, and is included in the message if the D2R message is not segmented. The transmission format identifier is expressed as an identifier indicating whether the D2R message is segmented or not.

[0169] In step S63, the ambient IoT device 300 transmits a D2R message including the transmission format identifier generated in step S62, using the access method selected in step S61. The D2R message may be a message used in device ID transmission shown in Step B of Fig. 11. Alternatively, the D2R message may be a message used in D2R data transmission shown in Step C2 of Fig. 11. Alternatively, the D2R message may be a message corresponding to Msg1 shown in Step 2 of Fig. 12. Alternatively, the D2R message may be a message used in upper layer data transmission shown in Step 3 of Fig. 12.

[0170] [Other Embodiments] In the above-described embodiments, it has been described that a D2R message and an R2D message are transmitted. These are assumed to be messages from the perspective of a layer higher than the PHY layer (e.g., a New AS layer). For example, from the perspective of the PHY layer, a D2R message may be transmitted as a D2R signal, and an R2D message may be transmitted as an R2D signal. For example, the A-IoT paging message (step S60) in FIG. 15 may be an A-IoT paging signal. The A-IoT paging message (step S60) in FIG. 15 may be transmitted as a D2R transmission signal, and the D2R transmission (step S83) may be transmitted as a D2R transmission signal.

[0171] The above-described operational flows are not limited to being implemented independently, but can be implemented by combining two or more operational flows. For example, some steps of one operational flow may be added to another operational flow, or some steps of one operational flow may be replaced with some steps of another operational flow. In each flow, it is not necessary to execute all steps, and only some steps may be executed. Furthermore, the order of steps in each flow may be changed as appropriate.

[0172] In the above-described embodiments and examples, an example in which the base station is an NR base station (gNB) has been described, but the base station may be an LTE base station (eNB) or a 6G base station. The base station may also be a relay node such as an IAB (Integrated Access and Backhaul) node. The base station may also be a DU of the IAB node. The UE 100 may also be an MT (Mobile Termination) of the IAB node. That is, the UE 100 may be a terminal function unit (a type of communication module) for the base station to control a relay that relays signals. Such a terminal function unit is referred to as an MT. Examples of MTs include, in addition to IAB-MT, NCR (Network Controlled Repeater)-MT and RIS (Reconfigurable Intelligent Surface)-MT.

[0173] The term "network node" primarily refers to a base station, but may also refer to a core network device or a part of a base station (CU, DU, or RU). A network node may also be configured by a combination of at least a part of a core network device and at least a part of a base station.

[0174] A program may be provided that causes a computer to execute each process performed by the UE 100 or the network node 200. The program may be recorded on a computer-readable medium. Using the computer-readable medium, the program can be installed on a computer. Here, the computer-readable medium on which the program is recorded may be a non-transitory recording medium. The non-transitory recording medium is not particularly limited, and may be, for example, a recording medium such as a CD-ROM and / or a DVD-ROM. Furthermore, circuits that execute each process performed by the UE 100 or the network node 200 may be integrated, and at least a part of the UE 100 or the network node 200 may be configured as a semiconductor integrated circuit (chip set, SoC: System on a chip).

[0175] The functions performed by the above-described communication devices (such as the UE 100 or the network node 200) may be implemented in circuitry or processing circuitry, including general-purpose processors, application-specific processors, integrated circuits, ASICs (Application Specific Integrated Circuits), a Central Processing Unit (CPU), conventional circuitry, and / or combinations thereof, programmed to perform the described functions. A processor includes transistors and / or other circuits and is considered to be circuitry or processing circuitry. A processor may be a programmed processor that executes programs stored in a memory. In this specification, a circuitry, unit, or means is hardware that is programmed to realize or executes a described function. The hardware may be any hardware disclosed herein or any hardware known to be programmed to realize or execute the described function. If the hardware is a processor, which is considered to be a type of circuitry, the circuitry, means, or unit is a combination of hardware and software used to configure the hardware and / or processor.

[0176] As used in this disclosure, the terms "based on" and "depending on / in response to" do not mean "based only on" or "depending only on," unless expressly stated otherwise. The term "based on" means both "based only on" and "based at least in part on." Similarly, the term "depending on" means both "depending only on" and "depending at least in part on." The terms "include," "comprise," and variations thereof do not mean including only the listed items, but may mean including only the listed items or may include additional items in addition to the listed items. Additionally, the term "or," as used in this disclosure, is not intended to mean an exclusive or. Furthermore, any reference to elements using designations such as "first," "second," etc., as used in this disclosure does not generally limit the quantity or order of those elements. These designations may be used herein as a convenient method of distinguishing between two or more elements. Thus, a reference to a first and a second element does not imply that only two elements may be employed therein or that the first element must precede the second element in some way. In this disclosure, where articles are added by translation, such as a, an, and the in English, these articles shall include the plural unless the context clearly indicates otherwise.

[0177] The above describes the embodiments in detail with reference to the drawings, but the specific configuration is not limited to that described above, and various design changes can be made within the scope that does not deviate from the gist of the invention.

[0178] This application claims priority to U.S. Provisional Application No. 63 / 679,887 (filed August 6, 2024), the entire contents of which are incorporated herein by reference.

[0179] (First Supplementary Note) The above-described embodiment can be summarized as in the supplementary note, but the supplementary note does not limit the embodiment.

[0180] (Supplementary Note 1) A communication method used in a mobile communication system, comprising: a step in which an ambient IoT (Internet of Things) device receives an R2D (Reader-to-Device) message including device identification information that identifies the ambient IoT device from a reader device that is a network node or user equipment of the mobile communication system; a step in which the ambient IoT device determines an access method to the reader device based on the device identification information; and a step in which the ambient IoT device transmits a D2R (Device-to-Reader) message to the reader device in accordance with the access method.

[0181] (Supplementary Note 2) The communication method according to Supplementary Note 1, wherein the R2D message is an ambient IoT paging message for initiating communication between the reader device and the ambient IoT device.

[0182] (Supplementary Note 3) The communication method according to Supplementary Note 1 or Supplementary Note 2, wherein the ambient IoT paging message includes a command for the reader device to instruct the ambient IoT device.

[0183] (Supplementary Note 4) The communication method according to any one of Supplementary Note 1 to Supplementary Note 3, wherein the determining step includes a step in which the ambient IoT device determines the access method based on a type of the identification information.

[0184] (Supplementary Note 5) The communication method according to any one of Supplementary Notes 1 to 4, wherein the determining step includes a step in which the ambient IoT device: selects an access method using contention-free access for transmitting the D2R message without performing contention resolution, depending on whether the type of the identification information is individual identification information that individually identifies the ambient IoT device; and selects an access method using random access that performs contention resolution, depending on whether the type of the identification information is group identification information that identifies a group to which the ambient IoT device belongs or all identification information that indicates all of the ambient IoT devices.

[0185] (Supplementary Note 6) The communication method according to any one of Supplementary Notes 1 to 5, wherein the selecting step is performed by the ambient IoT device selecting an access method using two-step random access that performs contention resolution using higher layer data when the type of the identification information is the group identification information, or selecting an access method using four-step random access that performs contention resolution using random identification information when the type of the identification information is the whole identification information.

[0186] (Supplementary Note 7) A communication method used in a mobile communication system, comprising: a step of receiving, by an ambient IoT device, an R2D message including device identification information that identifies the ambient IoT device and D2R access method information that indicates an access method from a leader device that is a network node or user equipment of the mobile communication system; and a step of the ambient IoT device transmitting a D2R message to the leader device in accordance with the access method.

[0187] (Supplementary Note 8) The communication method according to any one of Supplementary Notes 1 to 7, wherein the access method is one of a contention-free access access method in which the D2R message is transmitted without contention resolution, a two-step random access access method in which contention resolution is performed using random identification information, and a four-step random access procedure access method in which contention resolution is performed using higher layer data.

[0188] (Supplementary Note 9) A communication method for use in a mobile communication system, comprising: a step in which an ambient IoT device receives an R2D message including device identification information that identifies the ambient IoT device from a reader device; a step in which the ambient IoT device determines an access method; a step in which the ambient IoT device generates a transmission format identifier that indicates the access method; and a step in which the ambient IoT device transmits a D2R message including the transmission format identifier to the reader device in accordance with the access method.

[0189] (Supplementary Note 10) The communication method according to any one of Supplementary Note 1 to Supplementary Note 9, wherein the format identifier is included in the last D2R message when the D2R message is divided and transmitted.

[0190] (Supplementary Note 11) The communication method according to any one of Supplementary Note 1 to Supplementary Note 10, wherein the R2D message includes resource information indicating resources to be used for transmitting the D2R message. (Second Supplementary Note) Introduction At the RAN#102 meeting, a new study item on Ambient IoT solutions was approved.

[0191] At the RAN2 meeting, the overall A-IoT procedure initiated by A-IoT paging (or initial trigger message) was discussed and the following agreement was reached:

[0192] Agreement 1. As a base, the "inventory only" case is supported by the following steps: - Step A: A-IoT Paging - Step B: Sending Device ID (without Random Access or RA). Details require further study.

[0193] 2. As a base, the "inventory and command" case is supported by the following steps: - Step A: A-IoT paging - Step B: Sending device ID (random access or non-random access). Details require further study. - Step C: Sending data from reader to device (e.g. R2D command), and - Step D: Sending data from corresponding device to reader (e.g. feedback). Whether this is optional will be decided after discussions in other WGs.

[0194] The TR clarifies that inventory and commands do not mean that A-IoT paging includes both inventory and commands in the same message, which does not mean that inventory and commands are received from upper layers to the reader simultaneously.

[0195] 3. From the RAN2 perspective, consider the "command only" use case. Options to support this require further study. Include the command in the initial trigger message from the reader. Final feasibility will depend on the work / conclusion of SA2 and SA3. Use the "inventory and command" baseline procedure (i.e., trigger the inventory procedure first, then send the command).

[0196] Agreements 1. RAN2 will consider the following cases for A-IoT paging messages: - A message containing the ID of a single A-IoT device. - A message containing a group ID that maps to multiple A-IoT devices. - A message that does not contain an ID, i.e., a message addressed to all devices that can receive A-IoT messages. - A message containing multiple IDs of A-IoT devices. The necessity of this use case needs to be confirmed based on the discussion in SA2. The device ID, group ID, and scenario depend on the discussion in SA2.

[0197] 2. The A-IoT paging message indicates information (D2R message) for the device to determine the resources to use for response. Considering the discussion in RAN1, determine how (e.g., implicit / explicit / configured / pre-configured) and what resources (dedicated and / or shared) will be provided to the device.

[0198] 3. From RAN2's perspective, we assume that devices can receive as long as there is enough energy. Details of device monitoring will await further developments in RAN1.

[0199] This appendix discusses open or potential challenges regarding A-IoT paging.

[0200] Discussion The baseline procedures for the "Inventory only", "Inventory and Command", and "Command only" use cases are summarized in Figure 11, along with key agreements and open issues.

[0201] Identity and Resource Allocation: According to current agreement, in the simplest case, A-IoT paging will contain at least one identity and resource information for the device, regardless of the use case. The triggered device will initiate either A-IoT random access or contention-free access, depending on whether shared or dedicated resources are provided to the device.

[0202] Regarding the ID in the A-IoT paging, RAN2 agreed that it could be a Device ID, a Group ID, or "All devices" (if no ID is included). This naturally assumes that a Device ID is associated with a single device, and a Group ID is associated with a group of devices. RAN2 also agreed that multiple Device IDs may be included in one A-IoT paging message.

[0203] With respect to D2R resources, the usual assumption is that shared resources are shared by multiple devices, while dedicated resources are assigned to only a single device.

[0204] Therefore, a dedicated D2R resource for contention-free access may be indicatable only if it is associated with a device ID. The same may be applicable to the case of multiple device IDs (e.g., a list of device IDs), i.e., a different dedicated D2R resource is associated with each device ID.

[0205] On the other hand, shared D2R resources for contention-based random access can be used for any ID, i.e., device IDs (in the form of a list), group IDs, and "all devices", since contention-based random access, by definition, allows simultaneous access from different devices.

[0206] For simplicity, resource types will always be mapped to ID types, ie they will be viewed as follows:

[0207] Dedicated D2R resources are always used by a device when it is triggered by a device ID (including a list of device IDs, if necessary).

[0208] Shared D2R resources are always used by a device when it is triggered by a group ID or no ID (i.e., "all devices").

[0209] By using the above two assumptions, the resource information indicated in the A-IoT paging message can be minimized. For example, if the mapping of detailed time / frequency resources to time slot / frequency channel assignments is pre-configured for a device, the A-IoT paging needs to associate that time slot / frequency channel with either a device ID, a group ID, or "all devices." This detail can be discussed in the normative phase, so for now, RAN2 should agree on high-level assumptions for the A-IoT paging design.

[0210] Proposal 1: RAN2 should agree that dedicated D2R resources for contention-free access are always used for a single access from a single device, when the device is triggered by device ID.

[0211] Proposal 2: RAN2 should agree that shared D2R resources for contention-based random access are always used for multiple accesses from multiple devices when the devices are triggered by group ID and / or no ID (i.e., "all devices").

[0212] Time Slots and Reference Points For all D2R / R2D transmissions, it is natural to assume that they will be multiplexed at least in TDD (Time Division Duplex) fashion, i.e. using time slots. Whether multiple channels for multiple D2R transmissions are applicable (i.e. FDD (Frequency Division Duplex)) will depend on the progress of RAN1 and will be discussed further. An example of time slots and frequency channels is shown in Figure 16.

[0213] As agreed by RAN2, the A-IoT paging message is always the first message in the baseline procedure, regardless of the use case (i.e., "inventory" and / or "command"). Therefore, the A-IoT message can be the reference point for the time slots for subsequent D2R / R2D transmissions, including random access and contention-free access. For example, the first time slot starts upon completion of reception of the A-IoT paging. Apart from any details, RAN2 should agree on the basic principles of the frame structure for A-IoT communication.

[0214] Proposal 3: RAN2 agrees that A-IoT paging is the reference point for the time slot for all D2R / R2D transmissions.

[0215] Furthermore, it would be simple to consider a radio frame (or "round") that is initiated by an A-IoT paging and includes all opportunities for D2R / R2D transmissions, i.e., the radio frame is "self-contained," as shown in the dashed box in Figure 16. In other words, the next A-IoT paging starts a different / separate radio frame that is unrelated to any previous radio frame. From the device's perspective, the behavior can be very simple: the device monitors for A-IoT paging, and if an A-IoT paging is detected, it subscribes to the corresponding time slot for D2R / R2D. Once the radio frame is complete, the device resumes monitoring for A-IoT paging.

[0216] Proposal 4: RAN2 should agree that different A-IoT paging messages start different radio frames (or "rounds"), so that there is no relationship between any radio frames (i.e., all procedures are completed over multiple time slots within one radio frame).

[0217] 1: Mobile communication system 5: Network 10: RAN 20: CN 100: UE 110: Receiving unit 120: Transmitting unit 130: Control unit 140: Wireless communication unit 200: Network node 210: Transmitting unit 220: Receiving unit 230: Control unit 240: Network (NW) communication unit 250: Wireless communication unit 300: Ambient IoT device 310: Antenna 320: Modulator 330: Control unit 340: Memory 380: CN device 400: Reader device

Claims

1. A communication method used in a mobile communication system, comprising: an ambient IoT (Internet of Things) device receiving an R2D (Reader-to-Device) message including device identification information that identifies the ambient IoT device from a reader device that is a network node or user equipment of the mobile communication system; the ambient IoT device determining an access method to the reader device based on the device identification information; and the ambient IoT device transmitting a D2R (Device-to-Reader) message to the reader device in accordance with the access method.

2. The communication method of claim 1, wherein the R2D message is an ambient IoT paging message for initiating communication between the reader device and the ambient IoT device.

3. The communication method according to claim 1, wherein the ambient IoT paging message includes a command for the reader device to instruct the ambient IoT device.

4. The communication method of claim 1, wherein the determining step includes the ambient IoT device determining the access method based on the type of the device identification information.

5. The communication method of claim 4, wherein the determining step includes the ambient IoT device selecting an access method using contention-free access for transmitting the D2R message without performing contention resolution, depending on whether the type of the device identification information is individual identification information that individually identifies the ambient IoT device, and selecting an access method using random access that performs contention resolution, depending on whether the type of the device identification information is either group identification information that identifies a group to which the ambient IoT device belongs or all identification information that indicates all of the ambient IoT devices.

6. The communication method of claim 5, wherein the selection is performed by the ambient IoT device by selecting an access method using two-step random access that performs contention resolution using upper layer data when the type of the device identification information is the group identification information, and selecting an access method using four-step random access that performs contention resolution using random identification information when the type of the device identification information is the full identification information.

7. A communication method for use in a mobile communication system, comprising: an ambient IoT device receiving an R2D message from a leader device that is a network node or user equipment of the mobile communication system, the R2D message including device identification information that identifies the ambient IoT device and D2R access method information that indicates an access method; and the ambient IoT device transmitting a D2R message to the leader device in accordance with the access method.

8. A communication method according to claim 7, wherein the access method is one of a contention-free access method in which the D2R message is transmitted without contention resolution, a two-step random access method in which contention resolution is performed using random identification information, and a four-step random access procedure method in which contention resolution is performed using upper layer data.

9. A communication method for use in a mobile communication system, comprising: an ambient IoT device receiving an R2D message from a reader device, the R2D message including device identification information that identifies the ambient IoT device; the ambient IoT device determining an access method; the ambient IoT device generating a transmission format identifier that indicates the access method; and the ambient IoT device transmitting a D2R message including the transmission format identifier to the reader device in accordance with the access method.

10. A communication method according to claim 9, wherein the transmission format identifier is included in the last D2R message when the D2R message is transmitted in segments.

11. A communication method according to any one of claims 1, 7 and 9, wherein the R2D message includes resource information indicating resources to be used for transmitting the D2R message.

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