Communication method

Abstract

A communication method according to one aspect of the present invention is used in a mobile communication system. The communication method includes a step in which a reader apparatus, which is a network node or a user apparatus of a mobile communication system, receives, from an ambient IoT device, a message 1 (Msg1) including random identification information. The communication method also includes a step in which the reader apparatus, in response to receiving the Msg1, transmits a message 2 (Msg2) including random identification information to the ambient IoT device in a time slot associated with the transmission frequency channel of the Msg1.

Description

Communication method

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

[0002] In recent years, IoT (Internet of Things) has attracted attention in wireless communication technology. By interconnecting more "things," it is expected to improve production efficiency and enhance the comfort of life compared to the conventional situation. As technologies used in IoT, for example, there are barcodes and RFID (Radio Frequency Identifier). However, barcodes and RFID cannot perform long-distance wireless communication and it is difficult to support a large-scale network.

[0003] Therefore, in 3GPP (The Third Generation Partnership Project) (registered trademark. The same shall apply hereinafter), which is a standardization project for mobile communication systems, studies on the feasibility of new IoT technologies are being conducted. In this IoT technology, a technology with a larger number of connections and a higher device density than existing IoT technologies in 3GPP, such as NB-IoT (Narrow Band-IoT) or LTE-MTC (Long Term Evolution-Machine Type Communication), is assumed. Also, in this IoT technology, a technology with lower complexity and lower power consumption than existing 3GPP LPWA (Low Power Wide Area) technologies is assumed. The IoT devices used in this IoT technology are referred to as ambient IoT devices.

[0004] Most existing wireless communication devices use batteries that require manual replacement and / or charging. On the other hand, driving all IoT devices with batteries involves difficulties not only in terms of the cost of the IoT devices themselves but also in terms of the maintenance cost of the IoT devices.

[0005] The ambient IoT devices described above are intended to function as battery-less devices without energy storage capabilities. In this case, the ambient IoT devices function as purely battery-less devices that have no energy storage function whatsoever and are entirely dependent on the availability of external energy sources.

[0006] Alternatively, ambient IoT devices are envisioned to function as battery devices with limited energy storage capabilities. Limited energy storage capabilities refer to, for example, energy storage capabilities that do 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 opening up of new markets.

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

[0009] This disclosure provides a communication method that enables an ambient IoT device to properly receive Msg2.

[0010] The first communication method is a communication method used in a mobile communication system. The communication method includes the step of a reader device, which is a network node or user device of the mobile communication system, receiving a message 1 (Msg1) containing random identification information from an ambient IoT device. The communication method also includes the step of the reader device, upon receiving Msg1, transmitting a message 2 (Msg2) containing random identification information to the ambient IoT device in a time slot linked to the transmission frequency channel of Msg1.

[0011] The second communication method is a communication method used in a mobile communication system. The communication method includes the step of a reader device, which is a network node or user device of the mobile communication system, receiving a D2R (Device to Reader) message from an ambient IoT device. The communication method also includes the step of the reader device, upon receiving the D2R message, transmitting an R2D (Reader to Device) message to the ambient IoT device in a time slot linked to the transmission frequency channel of the D2R message.

[0012] Figure 1 is a diagram showing an example configuration of a mobile communication system according to the first embodiment. Figure 2 is a diagram showing an example configuration of a UE (User Equipment) according to the first embodiment. Figure 3 is a diagram showing an example configuration of a network node (gNB) according to the first embodiment. Figure 4 is a diagram showing an example configuration of a protocol stack according to the first embodiment. Figure 5 is a diagram showing an example configuration of a protocol stack according to the first embodiment. Figure 6 is a diagram showing an example configuration of an ambient IoT device according to the first embodiment. Figures 7(A) and 7(B) are diagrams showing examples of the topology of an ambient IoT device in the first embodiment. Figure 8 is a diagram showing an example configuration of an ambient IoT device according to the first embodiment. Figure 9 is a diagram showing an example configuration of an ambient IoT device according to the first embodiment. Figure 10 is a diagram showing an example configuration of a protocol stack for an ambient IoT device in the first embodiment. Figure 11 is a diagram showing an example of the overall procedure according to the first embodiment. Figure 12 is a diagram showing an example configuration of topology 2 according to the first embodiment. Figure 13 is a diagram showing an example resource placement according to the first embodiment. Figure 14 is a diagram showing the relationship between frequency channels and time slots according to the first embodiment. Figure 15 shows an example of operation according to the first embodiment.

[0013] A mobile communication system according to an embodiment will be described with reference to the drawings. In the drawings, identical or similar parts are denoted by the same or similar reference numerals.

[0014] [First Embodiment]

[0015] (1) Configuration of the Mobile Communication System The configuration of the mobile communication system according to the first embodiment will be described. Figure 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. In the following description, 5GS will be used as an example, but the mobile communication system may also have an LTE (Long Term Evolution) system applied to it at least partially. The mobile communication system may also have a 6th Generation (6G) system or later system applied to it at least partially.

[0016] The mobile communication system 1 comprises a network (NW) 10 and a user device (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, such as 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 installed on a sensor, a vehicle or a device installed on a vehicle (Vehicle UE), or an aircraft or a device installed on an aircraft (Aerial UE).

[0017] NW10 includes a radio access network (RAN) 20 and a core network (CN) 30. When the mobile communication system is a fifth-generation system (5GS), RAN20 is referred to as NG-RAN (Next Generation Radio Access Network) and CN30 is referred to as 5GC (5G Core Network).

[0018] RAN20 includes multiple network nodes 200 (network nodes 200a to 200c in the example in Figure 1). The network nodes 200 are interconnected via inter-network node interfaces. In RAN20, network nodes 200 are sometimes referred to as base stations. When a network node 200 is a base station, it may consist of a CU (Central Unit) and a DU (Distributed Unit) (i.e., functionally divided), and the two units may be connected by a front-haul interface. When the mobile communication system 1 is 5GS, the network nodes 200 are referred to as gNBs, the inter-network node interfaces as Xn interfaces, and the front-haul interfaces as F1 interfaces.

[0019] Furthermore, if at least a part of the mobile communication system 1 is an LTE system, the network node 200 may be an eNB (evolved Node B) which is an LTE base station. Also, if the mobile communication system 1 is a sixth-generation system or later, the network node 200 has the function of a base station and may be a device equivalent to a gNB or eNB.

[0020] Each network node 200 manages one or more cells. Each network node 200 performs wireless communication with the UE 100 that has established a connection with its own cell. Each network node 200 has functions such as wireless resource management (RRM), routing of user data (also simply referred to as "data"), and measurement and control functions for mobility control and scheduling. The term "cell" is used to indicate the smallest unit of a wireless communication area. The term "cell" is also used to indicate a function or resource that performs wireless communication with the UE 100. One cell belongs to one carrier frequency. One cell may be associated with one downlink component carrier and one uplink component carrier. The bandwidth corresponding to one cell (system bandwidth) may be divided into multiple bandwidth parts (BWP: Bandwidth Part). In the following explanation, the gNB may be used as an example of a network node 200.

[0021] CN30 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 UE100. The C-plane device communicates with the UE100 using NAS (Non-Access Stratum) signaling. The U-plane device controls data transfer. When the mobile communication system is 5GS, the C-plane device is called AMF (Access and Mobility Management Function), the U-plane device is called UPF (User Plane Function), and the interface between the network node 200 and the CN device 380 is called the NG interface.

[0022] Figure 2 shows an example configuration of UE100 (user device) according to the first embodiment. UE100 includes a receiving unit 110, a transmitting unit 120, and a control unit 130. The receiving unit 110 and the transmitting unit 120 constitute a wireless communication unit 140 that performs wireless communication with the network node 200.

[0023] 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 the radio signal received by the antenna into a baseband signal (received signal) and outputs it to the control unit 130.

[0024] The transmitting unit 120 performs various types of transmissions under the control of the control unit 130. The transmitting unit 120 includes an antenna and a transmitter. The transmitter converts the baseband signal (transmission signal) output by the control unit 130 into a wireless signal and transmits it from the antenna.

[0025] The control unit 130 performs various control and processing operations in the UE 100. Such processing includes processing in each layer described later. The operation of the UE 100 described above and later may also be controlled by the control unit 130. 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 processing by the processor. The processor may include a baseband processor and a CPU (Central Processing Unit). The baseband processor performs modulation, demodulation, encoding, and decoding of baseband signals. The CPU executes programs stored in memory and performs various processing operations.

[0026] Figure 3 shows an example configuration of a network node 200 (gNB) according to the first embodiment. The network node 200 includes 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.

[0027] The transmitting unit 210 performs various types of transmissions under the control of the control unit 230. The transmitting unit 210 includes an antenna and a transmitter. The transmitter converts the baseband signal (transmission signal) output by the control unit 230 into a wireless signal and transmits it from the antenna.

[0028] 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 the radio signal received by the antenna into a baseband signal (received signal) and outputs it to the control unit 230.

[0029] The control unit 230 performs various control and processing operations on the network node 200. Such processing includes processing at each layer described later. The operation of the network node 200 described above and later may also be controlled by 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 for processing by the processor. The processor may include a baseband processor and a CPU. The baseband processor performs modulation, demodulation, encoding, and decoding of baseband signals. The CPU executes programs stored in memory and performs various processing operations.

[0030] The network communication unit 240 is connected to an adjacent base station via the Xn interface, which is an inter-base station interface. The network communication unit 240 is connected to the CN device 380 via the NG interface, which is an inter-base station-core network interface. The network node 200 may consist of a CU (Central Unit) and a DU (Distributed Unit) (i.e., functionally divided), and the two units may be connected by the F1 interface, which is a front-haul interface.

[0031] Figure 4 shows the configuration of the protocol stack for the user plane's wireless interface that handles data.

[0032] The user plane radio interface protocol comprises a physical (PHY) layer, a MAC (Medium Access Control) layer, an RLC (Radio Link Control) layer, a PDCP (Packet Data Convergence Protocol) layer, and an SDAP (Service Data Adaptation Protocol) layer.

[0033] 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 UE100 and the PHY layer of network node 200 via a physical channel. The PHY layer of UE100 receives downlink control information (DCI) transmitted from network node 200 on the physical downlink control channel (PDCCH). Specifically, UE100 performs blind decoding of the PDCCH using a Radio Network Temporary Identifier (RNTI) and acquires the successfully decoded DCI as the DCI addressed to its own UE. The DCI transmitted from network node 200 has a CRC (Cyclic Redundancy Code) parity bit, which is scrambled by the RNTI, added to it.

[0034] The MAC layer performs data priority control, retransmission processing using Hybrid ARQ (HARQ: Hybrid Automatic Repeat reQuest), and random access procedures. Data and control information are transmitted between the MAC layer of UE100 and the MAC layer of network node 200 via the transport channel. The MAC layer of network node 200 includes a scheduler. The scheduler determines the transport format for the up and down links (transport block size, modulation and coding scheme (MCS)) and the resource blocks to be allocated to UE100.

[0035] The RLC layer transmits data to the receiving RLC layer using the functions of the MAC layer and PHY layer. Data and control information are transmitted between the RLC layer of UE100 and the RLC layer of network node 200 via a logical channel.

[0036] The PDCP layer performs header compression / decompression, encryption / decryption, etc.

[0037] The SDAP layer maps IP flows, which are the units under which the core network performs QoS (Quality of Service) control, to wireless bearers, which are the units under which the AS (Access Stratum) performs QoS control. Note that if the RAN is connected to the EPC, the SDAP is not required.

[0038] Figure 5 shows the configuration of the protocol stack of the wireless interface of the control plane that handles signaling (control signals).

[0039] The protocol stack of the control plane's wireless interface includes an RRC (Radio Resource Control) layer and a NAS (Non-Access Stratum) layer, instead of the SDAP layer shown in Figure 4.

[0040] RRC signaling for various settings is transmitted between the RRC layer of UE100 and the RRC layer of network node 200. The RRC layer controls the logical channel, transport channel, and physical channel in response to the establishment, re-establishment, and release of the wireless bearer. If there is a connection (RRC connection) between the RRC of UE100 and the RRC of network node 200, UE100 is in the RRC connected state. If there is no connection (RRC connection) between the RRC of UE100 and the RRC of network node 200, UE100 is in the RRC idle state. If the connection between the RRC of UE100 and the RRC of network node 200 is suspended, UE100 is in the RRC inactive state.

[0041] The NAS layer (also simply referred to as "NAS"), located above the RRC layer, performs session management and mobility management, etc. NAS signaling is transmitted between the NAS layer of the UE100 and the NAS layer of the CN device 380 (AMF). In addition to the wireless interface protocol, the UE100 also has an application layer, etc. Furthermore, the layer below the NAS layer is called the AS layer (also simply referred to as "AS").

[0042] (2) The mobile communication system 1 according to the ambient IoT device embodiment supports an ambient IoT device. Hereinafter, the ambient IoT device may be simply referred to as a "device".

[0043] (2.1) Overview of Ambient IoT Device FIG. 6 is a diagram showing a configuration example 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.

[0044] The ambient IoT device 300 may reflect the radio wave transmitted from the reader device (UE 100 or network node 200) and modulate the reflected wave to transmit the information inside the ambient IoT device 300. Generally, the technology of reflecting an unmodulated radio wave and modulating the reflected wave 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 an internal memory or writing information to the internal memory by using the backscattering communication function. In this case, the ambient IoT device 300 may receive a transmitted radio wave modulated with information and extract the information by demodulating the received radio wave.

[0045] The ambient IoT device 300 may be a battery-less IoT device. In this case, the ambient IoT device 300 converts received radio waves into energy (specifically, electricity) and operates using that energy. The ambient IoT device 300 may use an energy source other than radio waves, for example, by converting light, heat, magnetism, vibration, or sound into energy. Generally, this type of energy conversion is called energy harvesting. Known methods may be used for energy harvesting itself. Thus, 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 that charges the power acquired by the energy harvesting function. The ambient IoT device 300 may also be a wireless tag.

[0046] As shown in Figure 6, the ambient IoT device 300 includes an antenna 310, a modulator 320, a control unit 330, and a memory 340.

[0047] Antenna 310 receives an unmodulated carrier wave. This unmodulated carrier wave will be referred to as CW (Continuous Wave) below. Antenna 310 converts the received CW into a received signal and outputs this received signal to modulator 320. Antenna 310 also reflects the CW according to the transmission signal output from modulator 320 and transmits the reflected wave. This reflected wave will be referred to as BS (Back Scattering or Back Scatter) below. Antenna 310 performs BS transmission.

[0048] The modulator 320 may modulate the data read from the memory 340 under the control of the control unit 330 to generate a transmission signal. The modulator 320 outputs the modulation signal to the antenna 310. Also, the modulator 320 may demodulate the received signal from the antenna 310 in the modulator to obtain data under the control of the control unit 330. The modulator 320 outputs the obtained data to the control unit 330. In the ambient IoT device 300, specifically, the modulator 320 may be a switch. When the switch receives the received signal from the antenna 310, it turns on and outputs the received signal to the control unit 330. Also, 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 to the antenna 310. The switch may be an RF (Radio Frequency) switch. The switch may be composed of a transistor. Alternatively, the switch may be a mechanical switch that can be physically switched on or off.

[0049] The control unit 330 may have an environmental power generation 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 the driving power of the ambient IoT device 300. Also, the control unit 330 reads the information stored in the memory 340 and controls the modulator 320 to transmit a transmission signal corresponding to the information from the modulator 320. For example, the control unit 330 controls the on or off of the modulator 320 to control the reflectivity of the reflected wave (BS) (for example, set the reflectivity to 100% or 0%), and outputs a transmission signal corresponding to the information (for example, 1 bit) stored in the memory 340 from the modulator 320 to the antenna 310. Also, for example, the control unit 330 can output a transmission signal corresponding to multiple bits from the modulator 320 to the antenna 310 by controlling the timing of turning on or off the modulator 320. Thus, 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 the modulated reflected wave corresponding to the information stored in the memory 340 from the antenna 310.

[0050] Memory 340 holds various types of information. The information held in memory 340 may be information acquired when the ambient IoT device 300 functions as a sensor. Alternatively, the information held in memory 340 may be information specific to the ambient IoT device 300 that has been previously stored in memory 340. Examples of such specific information include identification information of the ambient IoT device 300 (or the group to which it belongs). The type of such identification information may be "Device ID", "Group ID", and / or "ALL". Under the control of the control unit 330, the information held in memory 340 can be read. Information may also be written to memory 340 under the control of the control unit 330. In this case, the control unit 330 (or modulator 320) converts the received signal received from the antenna 310 into a baseband signal in the baseband band, reads the information from the baseband signal, and writes the read information to memory 340.

[0051] The ambient IoT device 300 may have a limited battery. Limited means a battery that does not require manual replacement and / or charging, as described above. The ambient IoT device 300 may also have the ability to generate signals itself. In this case, the ambient IoT device 300 does not need to receive the CW signal and does not need to perform the BS transmission. That is, the ambient IoT device 300 transmits a transmission signal it generates itself via the antenna 310. As shown in Figure 6, the communication unit 345 may be configured with the antenna 310 and the modulator 320.

[0052] (2.2) Topology of the Ambient IoT Device Figures 7(A) and 7(B) are diagrams that show examples of the topology of the ambient IoT device 300. Figure 7(A) shows an example of "Topology 1", and Figure 7(B) shows an example of "Topology 2".

[0053] The device that performs wireless communication with the ambient IoT device 300 is referred to as the reader device (or "Reader") 400. As shown in Figure 7(A), in "Topology 1", the reader device 400 becomes the network node 200 (gNB). The reader device 400 may also be a relay node, which is a type of network node. For example, the reader device 400 may be an IAB (Integrated Access and Backhaul) node or an NCR (Network-Controlled Repeater). In "Topology 1", data and / or signaling related to the ambient IoT device 300 are transferred between the ambient IoT device 300 and the network node 200.

[0054] In the example shown in Figure 7(A), 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. This carrier wave may be reflected by the ambient IoT device 300. The receiver 220 of the network node 200 may receive the reflected wave from the ambient IoT device 300 under the control of the control unit 230, convert it into a baseband signal, and output it to the control unit 230.

[0055] As shown in Figure 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 communicates bidirectionally with the UE 100. The reader device 400 transmits data and / or signaling related to the ambient IoT device 300 between the network node 200 and the ambient IoT device 300.

[0056] In the example shown in Figure 7(B), the UE 100 performs wireless communication over the Uu interface with the network node 200. 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 (receiving unit 110 and transmitting unit 120) of the UE 100 can communicate wirelessly with the ambient IoT device 300. For example, the receiving unit 110 of the UE 100 may receive reflected waves reflected by the ambient IoT device 300 under the control of the control unit 130. The receiving unit 110 may receive the received reflected waves as a wireless signal, convert them into a baseband signal, and output them to the control unit 130. The transmitting unit 120 of the UE 100 may transmit an unmodulated carrier wave under the control of the control unit 130. This carrier wave may be reflected by the ambient IoT device 300.

[0057] (2.3) Detailed Configuration Example of Ambient IoT Devices In 3GPP, it has been agreed that there are three types of ambient IoT devices 300: "Device 1", "Device 2a", and "Device 2b".

[0058] "Device 1" is, for example, a device whose peak power consumption is "1 μW" or less, which does not perform amplification in either the DL direction or the UL direction, and which performs backscattering transmission using an externally provided carrier wave.

[0059] "Device 2a" is, for example, a device whose peak power consumption is "several hundred μW" or less, which performs amplification in the DL direction and / or UL direction, and which performs backscattering transmission using an externally provided carrier wave.

[0060] "Device 2b" is, for example, a device with a peak power consumption of "several hundred μW" or less, which performs amplification in the DL direction and / or UL direction, and which generates UL transmission within the device. Furthermore, all device types have an energy storage function.

[0061] Figure 8 is a diagram showing an example configuration of the ambient IoT device 300 of "Device 1" according to the first embodiment.

[0062] Device 1 includes an antenna 310, a matching network 350, an RF energy harvester 351, a PMU (Power Management Unit) 352, an energy storage unit 353, an RF BPF (Radio Frequency Band Pass Filter) 354, an RF envelope detector (or envelope detector) 355, a BB LPF (Base Band Low Pass Filter) 356, a comparator 357, a baseband logic 358, a memory 359, a backscattering modulator 360, and a clock generator 361.

[0063] The matching network 350 matches the impedance of the antenna 310 with 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.

[0064] The RF energy harvester 351 has an energy harvesting function and extracts energy from radio signals. The RF energy harvester 351 may also have a rectifier that converts the AC component of the radio signal into the DC component of the radio signal.

[0065] The PMU 352 manages (or controls) the storage of energy from the RF energy harvester 351, as well as managing (or controls) the supply of power to blocks that require power.

[0066] The energy storage unit 353 stores energy from the RF energy harvester 351.

[0067] The RF BPF354 outputs radio signals in a specific frequency band. The RF BPF354 is used to improve selectivity. Note that the RF BPF354 may not be present in "Device 1" depending on the implementation.

[0068] 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.

[0069] The BB LPF 356 removes the high-frequency components of the baseband signal output from the RF envelope detector 355, improving the quality of the signal input to the comparator 357.

[0070] The comparator 357 determines whether the input signal output from the BB LPF 356 is "high" or "low". Note that the comparator 357 may detect not only two values, "high" and "low", but also three or more values.

[0071] The baseband logic 358 includes functional blocks such as encoders, decoders, and controllers.

[0072] Memory 359 stores device identification information (or device ID) for identifying (or distinguishing) the 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 other information. Memory 359 may also be a memory (register) that temporarily stores necessary information only while the energy stored in the energy storage unit 353 is available.

[0073] The backscattering modulator 360 modulates the output signal from the baseband logic 358 into a backscattering signal by switching the impedance. Alternatively, the backscattering modulator 360 modulates the high-frequency signal (e.g., CW) input from the antenna 310 into a backscattering signal by switching the impedance (antenna or transmission line impedance) based on the output signal (digital signal or digital data) from the baseband logic 358. For example, the backscattering modulator 360 can modulate and then reflect the high-frequency signal input from the antenna 310 by terminating the high-frequency input signal at digital data "0" (not reflecting) and leaving the high-frequency input signal open at digital data "1" (reflecting).

[0074] The clock generator 361 generates the necessary clock signal within the device.

[0075] 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 Figure 6. Also, the PMU 352 and baseband logic 358 may be included in the control unit 330 shown in Figure 6. Furthermore, the memory 359 may correspond to the memory 340 shown in Figure 6.

[0076] Figure 9 is a diagram showing an example configuration of the ambient IoT device 300 of "device 2a" according to the first embodiment.

[0077] Device 2a, in addition to Device 1 shown in Figure 8, 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.

[0078] The LNA365 amplifies the output signal from the RF BPF354 (i.e., the signal from the reader device (network node 200 or UE100)) to improve the signal strength and sensitivity at the receiving end.

[0079] The baseband amplifier 366 amplifies the baseband signal output from the RF envelope detector 355, improving the signal strength.

[0080] The large frequency shifter 367 shifts the frequency of the backscattering signal from one frequency (e.g., FDD-DL frequency) to another frequency (e.g., FDD-UL frequency).

[0081] The Energy Harvester 369 performs energy harvesting using methods other than RF signals. Specifically, energy harvesting methods include sunlight (solar panels), vibration (vibration power generation), and heat (thermal power generation), but are not limited to these.

[0082] The above describes an example configuration of "device 2a". In the example block configuration shown in Figure 9, in relation to the example block configuration shown in Figure 6, the LNA 365, baseband amplifier 366, large frequency shifter 367, and reflection amplifier 368 may be further included in the modulator 320.

[0083] (2.4) Protocol stack for ambient IoT device Figure 10 is a diagram showing an example of the configuration of a protocol stack for an ambient IoT device 300 according to the first embodiment.

[0084] The wireless interface protocol comprises a PHY layer and an Ambient IoT (A-IoT) MAC layer. Communication between the reader device 400 and the Ambient IoT device 300, described later, may be performed by at least one of the layers shown in Figure 10. A new layer (New AS Protocol) may be introduced as a layer above the Ambient IoT MAC layer.

[0085] 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 the PRDCH (Physical Reader to Device channel). The channel used for R2D transmission is also called the R2D channel. The R2D channel may also be the PRDCH. The message transmitted using the R2D channel is called the R2D message. The R2D message may also be a message defined in "A-IoT MAC" (or "New AS Protocol").

[0086] 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 "D2R (Device to Reader) transmission") is called the PDRCH (Physical Device to Reader channel). The channel used for D2R transmission is also called the D2R channel. The D2R channel may also be the PDRCH. The message transmitted using the D2R channel is called the D2R message. The D2R message may also be a message defined in "A-IoT MAC" (or "New AS Protocol").

[0087] For example, in "Topology 1," the physical channel used for R2D transmission from network node 200 to ambient IoT device 300 is PRDCH, and the physical channel used for D2R transmission from ambient IoT device 300 to network node 200 is PDRCH. Similarly, in "Topology 2," the physical channel used for R2D transmission from UE100 to ambient IoT device 300 is PRDCH, and the physical channel used for D2R transmission from ambient IoT device 300 to UE100 is PDRCH.

[0088] Furthermore, the control plane between the reader device 400 and the ambient IoT device 300 lacks an RRC layer, and therefore does not support RRC connection management, Layer 3 (L3) measurement reporting, or periodic system information and master information blocks (MIBs). In addition, the ambient IoT device 300 does not support conventional paging messages.

[0089] The user plane between the reader device 400 and the ambient IoT device 300 does not contain the SDAP layer, PDCP layer, or RLC layer. Furthermore, the AS layer, which is above the PHY layer, does not support HARQ and RLC AM (Acknowledge Mode).

[0090] (3) Operation of the mobile communication system The operation of the mobile communication system 1 having the ambient IoT device 300 will be described.

[0091] (3.1) The overall procedure diagram 11 is a diagram showing an example of the overall procedure in the mobile communication system 1 according to the first embodiment. In Figure 11, an example of the overall procedure after the reader device 400 receives a Service Request is shown. If the reader device 400 receives a Service Request again, the overall procedure shown in Figure 11 is repeated. Furthermore, the overall procedure shown in Figure 11 is a summary of the procedures currently agreed upon in 3GPP. Note that Figure 11 shows an example of "Topology 1" in which the gNB acts as the reader device 400 and communicates with the ambient IoT device 300.

[0092] Step S1: The reader device 400 receives a service request from an upper node. Alternatively, it may receive a service request from a lower layer (e.g., the AS layer) or an upper layer (e.g., the NAS layer) within the reader device 400.

[0093] Firstly, the service request includes, as visible information for the reader device 400, at least one of the following: 1) the type of service, 2) the ambient IoT device 300 to be called, and 3) the approximate number of ambient IoT devices 300 to be called.

[0094] An example of a service type is "inventory." "Inventory" is one of the services (use cases) used, for example, to check for the existence of an ambient IoT device 300. Another example of a service type is "command." "Command" is one of the services (use cases) used to issue various commands to the ambient IoT device 300, such as read, write, or disable. Furthermore, there may be a service type called "inventory and command" which performs both "inventory" and "command" simultaneously. A service request may include information that identifies which service it is as a service type.

[0095] Secondly, service requests also include transparent information that cannot be seen by the reader device 400. Transparent information includes the contents of "commands" (such as read commands). Transparent information also includes "inventory." Transparent information may also include the contents of services instructed by the higher-level node.

[0096] In the case of "Topology 1," the service request may be included in a message sent from the CN device 380 to the gNB, for example, in an NG-AP (Application Protocol) message. In the case of "Topology 2," the service request may be included in a message sent from the gNB to the UE 100, for example, in an RRC message or a System Information Block (SIB).

[0097] Step S2: In response to receiving a service request, the reader device 400 transmits an ambient IoT paging signal (ambient IoT paging signal) to the ambient IoT device 300, similar to a conventional paging signal. The ambient IoT paging signal may be a signal for the reader device 400 to initiate communication with the ambient IoT device 300. Alternatively, the A-IoT paging signal may be a call signal (or trigger signal) that initiates a call (or trigger) to the ambient IoT device 300.

[0098] Firstly, the ambient IoT paging signal includes device identification information that identifies the ambient IoT device 300. Device identification information may be used to identify the ambient IoT device 300 to be called. There are different types of device identification information, such as a "device ID" (individual identification information) that identifies each ambient IoT device 300 individually. There is also a "group ID" (group identification information) that identifies the group to which the ambient IoT devices belong. Furthermore, there is an "ALL" (all identification information) type of device identification information that represents all ambient IoT devices. However, if the ambient IoT paging message does not include device identification information, it will represent "ALL".

[0099] Secondly, the ambient IoT paging signal includes resource information. This resource information is used for transmission from the ambient IoT device 300 to the reader device 400 (for example, Msg1 or D2R messages).

[0100] Thirdly, the ambient IoT paging signal may include an R2D command. The R2D command represents a command sent from the reader device to the ambient IoT device 300. The R2D command is used in the case of a "command" service, and the command included in the service request (step S1) may be an R2D command.

[0101] The ambient IoT paging signal may also be an initial trigger signal. An initial trigger signal is, for example, a signal that includes an ambient IoT device that needs to respond to a service request. The reader device 400 can use the ambient IoT paging signal as an initial trigger signal to call the ambient IoT device 300.

[0102] The ambient IoT device 300 receives an ambient IoT paging signal. The ambient IoT device 300 determines whether it has successfully received the ambient IoT paging signal. If successful, it checks the device identification information. If it matches its own device identification information (i.e., it is being called), it performs the next step S3. The following explanation assumes that the ambient IoT paging signal has been successfully received.

[0103] Steps S3 to S7 (Random Access Procedure): Steps S3 to S7 represent an RA procedure for ambient IoT devices, similar to normal random access (RA). The RA procedure from steps S3 to S7 performs contention resolution to avoid D2R message transmission conflicts.

[0104] There are two types of RA procedures: "3-step RA" and "2-step RA". In "3-step RA", three messages (Msg1, Msg2, and Msg3) from step S4 to step S7 are used. In "2-step RA", two messages (Msg1 and Msg2) other than Msg3 in step S7 are used. There is also a conflict-free procedure called "conflict-free" as a method of accessing the reader device 400 from the ambient IoT device 300. In "conflict-free", Msg1 to Msg3 are skipped, and after receiving the ambient IoT paging signal (step S2), a D2R message is sent (step S9).

[0105] In step S3, the ambient IoT device 300 determines and / or selects a resource (or access opportunity).

[0106] In step S4, the ambient IoT device 300 sends message 1 (Msg1) to the reader device 400 using the resource selected in step S3. Msg1 may include a random ID. In "3-step RA", the random ID is a required component, but in "2-step RA", the random ID is used optionally. The random ID may be random identification information generated by the ambient IoT device. The number of bits in the random ID is fixed at "16" bits.

[0107] In step S5, the reader device 400 sends message 2 (Msg2) containing the random ID to the ambient IoT device 300. Since the random ID is used as is in Msg2, it can become echo information. In the case of "2-step RA", the random ID may not be included in Msg1, but in this case, 3GPP has not yet determined what information in Msg2 will be used as echo information.

[0108] In step S6, the ambient IoT device 300 determines whether or not the conflict has been resolved. The ambient IoT device 300 considers the conflict resolution to be successful (OK) if the random ID sent in Msg1 matches the random ID received in Msg2. In other words, the ambient IoT device 300 can determine that the resources used to send Msg1 did not conflict with the resources used to send Msg1 from other ambient IoT devices, since the random ID sent in Msg1 was received in Msg2. On the other hand, the ambient IoT device 300 considers the conflict resolution to have failed if the two random IDs do not match. In this case, the ambient IoT device 300 could determine that the resource used to send Msg1 was in conflict with a resource used to send Msg1 from another ambient IoT device, since it could not receive the random ID sent in Msg1 in Msg2. Therefore, the conflict resolution could be considered to have failed. Conflict resolution could also be a procedure that determines whether or not the resources used to send Msg1 are in conflict.

[0109] In the case of "3-step RA," in step S7, the ambient IoT device 300 sends message 3 (Msg3) to the reader device 400. The resources used to send Msg3 are explicitly notified by Msg2. Msg3 may also be a response (ACK / NACK) to step S6 (conflict resolution). Msg3 may include higher layer data. The higher layer data may be the device ID of the ambient IoT device 300. Note that in the case of "conflict-free," higher layer data may also be included in the D2R message (step S9).

[0110] In step S7, the ambient IoT device 300 may send a very first D2R message to the reader device 400 separately from Msg3. The ambient IoT device 300 may also send the very first D2R message after step S7.

[0111] The early D2R message may include an energy status report. An ambient IoT device 300 may not have energy, and an early D2R message including an energy status report may be used as a follow-up message for such an ambient IoT device 300. Alternatively, the early D2R message may include a simple message size report. Alternatively, the early D2R message may include a failure indicator or a success indicator. The failure indicator and success indicator may be used for failure and success in conflict resolution (step S6), respectively. Alternatively, the failure indicator and success indicator may be used for failure and success in data transmission and reception (step S8 or step S9), respectively.

[0112] Step S8: The reader device 400 sends an R2D message to the ambient IoT device 300. The R2D message may include an R2D command.

[0113] Step S9: The ambient IoT device 300 sends a D2R message to the reader device 400. The D2R message may include feedback information corresponding to the R2D command (step S8).

[0114] Step S10: The reader device 400 transmits a Subsequent Ambient IoT paging signal (successor Ambient IoT paging signal) to the Ambient IoT device 300. The Subsequent Ambient IoT paging signal is, for example, a signal associated with the same service request as the Ambient IoT paging signal (Step S2), and is a signal that follows the said Ambient IoT paging signal.

[0115] (3.2) Agreements related to Topology 2 Figure 12 shows an example of the configuration of Topology 2 according to the first embodiment. Figure 12 shows a summary of the current agreements in 3GPP related to Topology 2.

[0116] As shown in Figure 12, an ambient IoT air interface (AI) is used between the reader device 400 and the ambient IoT device 300. In topology 1 (Figure 11), an ambient IoT air interface is also used between the reader device 400 and the ambient IoT device 300, but the ambient IoT air interface of topology 1 is completely reused in topology 2. In other words, from the perspective of the ambient IoT device 300, topology 2 is transparent to topology 1 and is not affected by differences in topology.

[0117] In topology 2, network 10 controls the resources of the ambient IoT air interface. Resource control is performed via L2 (Layer 2) messages or L3 (Layer 3) messages.

[0118] (3.3) Resource Placement Example Next, an example of resource placement used for communication with the ambient IoT device 300 will be described.

[0119] Figure 13 is a diagram showing an example of resource placement according to the first embodiment.

[0120] In Figure 13, the "R2D channel" represents the frequency resources used for communication from the reader device 400 to the ambient IoT device 300. In Figure 13, the "R2D channel" represents an example where the frequency resources of one channel, "Channel #1," are used. This assumes that by using only one channel for the "R2D channel," the ambient IoT device 300 can have a simple configuration without requiring a hardware configuration that supports multiple channels for receiving signals from the reader device 400. However, it is also possible for the "R2D channel" to use the frequency resources of multiple channels.

[0121] The "D2R channel" represents the frequency resources used for communication from the ambient IoT device 300 to the reader device 400. In the example shown in Figure 13, the "D2R channel" represents an example where two channels of frequency resources ("channel #2" and "channel #3") are used. The ambient IoT device 300 can transmit to the reader device 400 using "backscattering" at a predetermined frequency, and Figure 13 assumes that either "channel #2" or "channel #3" is used as the predetermined frequency. The "D2R channel" may use three or more channels of frequency resources. Alternatively, the "D2R" channel may use only one channel of frequency resources. That is, if frequency multiplexing is not performed for the "D2R" channel, only one channel may be used.

[0122] When this resource allocation is used, the "3-step RA" procedure in the ambient IoT device 300 can be summarized as follows:

[0123] Step 0: The ambient IoT device 300 awaits the ambient IoT paging signal. The ambient IoT paging signal may use PRDCH as the physical channel. The ambient IoT paging signal uses "channel #1" as the frequency resource, as shown in Figure 13.

[0124] Step 1: The ambient IoT device 300 receives the ambient IoT paging signal, checks whether the device ID matches its own device ID, and obtains the transmission resource information for Msg1. In Figure 13, if a block consisting of one channel's frequency resource and one slot's time resource is considered one resource block (RB), then in the example shown in Figure 13, the resource information for Msg1 uses 4RBs indicated as "RA Msg1 resource". Basically, resources for the PDRCH are allocated based on the resource information contained in the signal notified by the PRDCH. The ambient IoT paging signal contains resource information. Therefore, resource allocation for Msg1 may be performed based on this resource information. Resource allocation may be performed so that one ambient IoT device 300 uses one RB. Resource allocation may be performed so that multiple ambient IoT devices 300 share one RB.

[0125] Step 2: The ambient IoT device 300 transmits Msg1 using the resources for Msg1. The physical channel used to transmit Msg1 may be the PDRCH.

[0126] Step 3: The ambient IoT device 300 waits for Msg2 (PRDCH). In the example shown in Figure 13, four time slots (4RB) of resources ("RA Msg2 resources") are used to send Msg2.

[0127] Step 4: The ambient IoT device 300 receives Msg2 (PRDCH), performs conflict resolution using the echo information contained in Msg2, and obtains the transmission resource for Msg3. The transmission resource for Msg3 is explicitly notified by Msg2. The transmission resource for Msg3 may be the "CF D2R resource" (4RB) shown in Figure 13. In the case of "conflict-free" conditions, the "CF D2R resource" (4RB) shown in Figure 13 is used to transmit the D2R message. In the case of "conflict-free" conditions, Msg1 and Msg2 are skipped, so the resource information contained in the ambient IoT paging signal may be used as resource allocation information for the D2R transmission message.

[0128] Step 5: In the case of "3-step RA," the ambient IoT device 300 sends Msg3 (PDRCH) using the resource for Msg3 ("CF D2R resource" in Figure 13). In the case of "conflict-free," the ambient IoT device 300 sends a D2R message (PDRCH) using the "CF D2R resource."

[0129] Step 6: The ambient IoT device 300 waits for an R2D message (PRDCH). The R2D message may be the "CF R2D resource" shown in Figure 13.

[0130] Step 7: The ambient IoT device 300 receives an R2D message (PRDCH). If the R2D message contains a "command", a D2R message (PDRCH) may be sent using slots #13 and later.

[0131] Furthermore, considering the collision probability caused by the transmission of Msg1, the transmission resources for Msg1 may be greater than those shown in Figure 13, depending on the number of ambient IoT devices 300 that can communicate with the reader device 400. Similarly, the transmission resources for D2R messages may also be greater than those shown in Figure 13. Likewise, the resources for Msg2 or R2D messages may be greater or less than those shown in Figure 13. In other words, while Figure 13 shows an example of "12 slots" of resources used in a series of communication procedures for one ambient IoT paging signal in the time direction, more than "12 slots" or fewer than "12 slots" may be used depending on the number of ambient IoT devices 300.

[0132] (4) Communication method according to the first embodiment Next, a communication method according to the first embodiment will be described.

[0133] In the contention-based random access (CRA) procedure ("3-step RA" and "2-step RA"), the ambient IoT device 300 sends Msg1 containing a random ID to the reader device 400 (step S4 in Figure 11). Then, the reader device 400 sends Msg2 containing the random ID as echo information to the ambient IoT device 300 (step S5).

[0134] In the current 3GPP, it is only agreed that resource information should be included in ambient IoT paging messages; the correspondence between the resources in Msg1 and Msg2 is not specified.

[0135] Therefore, it is conceivable that each ambient IoT device 300 transmits Msg1 using the same frequency channel #A resource. In this case, the reader device 400 may transmit multiple Msg2, each containing a random ID received from each ambient IoT device 300, using a single transmission slot. Alternatively, it is conceivable that each ambient IoT device 300 transmits Msg1 using different frequency channels, and in this case as well, the reader device 400 may transmit multiple Msg2, each containing a random ID, using a single transmission slot. In either case, because multiple Msg2 are transmitted using a single transmission slot, the ambient IoT device 300 may not be able to receive its own Msg2 and therefore may not be able to determine its own random ID.

[0136] Therefore, the objective of the first embodiment is to enable the ambient IoT device 300 to properly receive Msg2.

[0137] Therefore, in the first embodiment, Msg2 is transmitted using a different time slot for each transmission frequency channel of Msg1. Specifically, a reader device (e.g., reader device 400), which is a network node (e.g., network node 200) or user device (or UE 100) of a mobile communication system, receives message 1 (Msg1) containing random identification information from an ambient IoT device (e.g., ambient IoT device 300). Secondly, in response to receiving Msg1, the reader device transmits message 2 (Msg2) containing the random identification information to the ambient IoT device in a time slot associated with the transmission frequency channel of Msg1.

[0138] Figure 14 is a diagram illustrating an example of the correspondence between the transmission frequency channels of Msg1 and the transmission slots of Msg2. An ambient IoT paging message includes, for example, the resource information of Msg1 shown in Figure 14. In the example shown in Figure 14, the resource information of Msg1 includes "N" frequency channels in the frequency direction and "M" time slots (hereinafter sometimes referred to as "slots") in the time direction. Furthermore, it is assumed that the resource information of Msg1 is assigned "Ch.1", "Ch.2", ..., "Ch.N" in order of increasing frequency channels.

[0139] Ambient IoT device 300A receives an ambient IoT paging message containing resource information for Msg1. Ambient IoT device 300A selects one of the resources from the resource information. For example, ambient IoT device 300A selects the resource for frequency channel "Ch.1". Ambient IoT device 300A uses the frequency channel "Ch.1" to send Msg1 containing random ID "A".

[0140] The reader device 400 receives Msg1 transmitted from the ambient IoT device 300 using the frequency channel "Ch.1". The reader device 400 transmits Msg2 using the time slot "Slot #1" associated with the frequency channel "Ch.1". Msg2 in "Slot #1" contains the random ID "A" of the ambient IoT device 300A that was included in Msg1 received on the frequency channel "Ch.1".

[0141] Furthermore, the ambient IoT device 300B uses the resources of frequency channel "Ch.2" to transmit Msg1 containing the random ID "B". In this case, the reader device 400 uses "slot #2" associated with frequency channel "Ch.2" to transmit Msg2. Msg2 in "slot #2" contains the random ID "B" of the ambient IoT device 300B that was included in Msg1 received on the frequency channel "Ch.2".

[0142] In this way, the reader device 400 uses different time slots for each transmission frequency channel of Msg1 to transmit Msg2, each containing multiple random IDs transmitted from multiple ambient IoT devices 300. As a result, for example, an ambient IoT device 300 can receive Msg2 at a different timing than other ambient IoT devices 300, and can properly receive the random ID addressed to it. Therefore, ambient IoT devices 300 can properly receive Msg2.

[0143] In Figure 14, the channels are labeled "Ch.1", "Ch.2", ..., "Ch.N" in ascending order of frequency, but they may also be labeled "Ch.1", "Ch.2", ..., "Ch.N" in descending order of frequency. Information indicating whether the frequency channels are in ascending or descending order of frequency may be notified in advance by the reader device 400, or it may be defined in the specifications. If notified, the ambient IoT paging message may include information indicating whether the channels are in descending or descending order of frequency.

[0144] Furthermore, Figure 14 shows an example where "Ch.1" is linked to "Slot #1", "Ch.2" is linked to "Slot #2", ..., and "Ch.N" is linked to "Slot #N". However, the relationship between each transmission frequency channel and each time slot can be any relationship as long as there is a one-to-one correspondence. For example, "Ch.1" may be linked to "Slot #N", "Ch.2" may be linked to "Slot #(N-1)", ..., and "Ch.N" may be linked to "Slot #1". The correspondence between the transmission frequency and the time slot may also be notified in advance from the reader device 400, or it may be defined in the specifications. If notified, the ambient IoT paging message may include information indicating the correspondence.

[0145] (4.1) Figure 15 of the operation example according to the first embodiment is a diagram showing an operation example according to the first embodiment.

[0146] As shown in Figure 15, in step S20, the transmitting unit (transmitting unit 120 or transmitting unit 210) of the reader device 400 transmits an ambient IoT paging message. The transmitting unit transmits one or more ambient IoT paging messages to a plurality of ambient IoT devices 300. The plurality of ambient IoT paging messages may call (trigger) a single ambient IoT device 300 or a plurality of ambient IoT devices 300, and may include a single device ID or a group ID. Each ambient IoT paging message includes resource information for Msg1 (for example, Figure 14). The communication unit 345 of each ambient IoT device 300 receives the ambient IoT paging message.

[0147] In step S21, the control unit 330 of the ambient IoT device 300 selects one of the resources from the resource information of Msg1. The control unit 330 stores in the memory 340 information indicating which frequency channel was selected for that resource.

[0148] The communication unit 345 of the ambient IoT device 300 then transmits Msg1 using the selected resource. Multiple ambient IoT devices 300 may each transmit Msg1 using different frequency channels. Multiple ambient IoT devices 300 may also transmit Msg1 using the same slot. Msg1 contains a random ID generated by each ambient IoT device 300. The random ID is represented by a fixed 16 bits.

[0149] The receiving unit (receiving unit 110 or receiving unit 220) of the reader device 400 receives Msg1. The receiving unit of the reader device 400 receives multiple Msg1 transmitted from multiple ambient IoT devices 300. At this time, the control unit (control unit 130 or control unit 230) of the reader device 400 checks which frequency channel each Msg1 was received on.

[0150] In step S22, the control unit of the reader device 400 reads the random ID contained in the Msg1 received in step S21.

[0151] In steps S23 and S24, the transmitting unit of the reader device 400 transmits Msg2 at a predetermined timing in response to receiving Msg1 in step S21.

[0152] Firstly, the predetermined timing is a specific slot associated with the transmission frequency channel of Msg1. The control unit of the reader device 400 checks the slot associated with the frequency channel of Msg1 (the transmission frequency channel of Msg1) confirmed in step S21. Then, the transmission unit of the reader device 400 transmits Msg2, which includes the random ID contained in Msg1, in that slot.

[0153] Secondly, each of the multiple Msg2s contains multiple random IDs received in step S21 as echo information. The transmitting unit of the reader device 400 includes the random IDs contained in each Msg1 in Msg2 and transmits Msg2 in a slot associated with the frequency channel at the time each Msg1 was received.

[0154] The communication unit 345 of the ambient IoT device 300 receives Msg2. The control unit 330 of the ambient IoT device 300 reads the frequency channel used to transmit Msg1 from memory and receives Msg2 using the slot associated with that frequency channel. Then, the communication unit 345 of the ambient IoT device 300 sets the random ID contained in Msg2 as a random ID addressed to itself.

[0155] In step S25, the control unit 330 of the ambient IoT device 300 compares the random ID assigned to itself in step S24 with the random ID stored in the memory 340 to resolve the conflict.

[0156] (4.2) Other Operation Examples According to the First Embodiment In the first embodiment, the relationship between Msg1 and Msg2 was described, but the embodiment is not limited thereto. For example, the first embodiment can also be applied to the relationship between "D2R transmission" and "R2D transmission". For example, it can also be applied to the relationship between "CF D2R" and "CF R2D" shown in Figure 13. For example, the following cases can be envisioned.

[0157] In other words, in the case of "3-step RA", during "D2R transmission" ("CF D2R"), each of the multiple ambient IoT devices 300 sends Msg3. Then, during "R2D transmission" ("CF R2D"), the reader device 400, upon receiving Msg3, sends an R2D message containing a "command" (R2D command) to the multiple ambient IoT devices 300.

[0158] In the case of "2-step RA," during "D2R transmission" ("CF D2R"), each of the multiple ambient IoT devices 300 sends a D2R message containing its device ID to the reader device 400. Then, during "R2D transmission," the reader device 400 sends an R2D message containing a "command" to each device ID (or ambient IoT device 300) received in "D2R transmission." Note that in the case of "2-step RA," the device ID can also be transmitted in Msg1. In this case, the reader device 400 may use the "R2D transmission" ("CF R2D") resource to send a "command" to the device ID (or ambient IoT device 300) received in Msg1. In this case, the relationship between "RA Msg1" and "CF R2D" corresponds to the relationship between "Msg1" and "Msg2" in the first embodiment.

[0159] Furthermore, in the "conflict-free" case, after skipping Msg1 and Msg2, in the "D2R transmission" process, multiple ambient IoT devices 300 send D2R messages including device IDs, and in the "R2D transmission" process, the reader device 400 sends R2D messages including "commands" (R2D commands) to each device ID (of the ambient IoT device 300).

[0160] Thus, a similar relationship between Msg1 and Msg2 can be found in the relationship between "D2R transmission" and "R2D transmission". Furthermore, in the case of "D2R transmission" and "R2D transmission", as in the first embodiment, "R2D transmission" may be performed in a time slot linked to the transmission frequency channel of "D2R transmission".

[0161] Furthermore, it is possible to find similar resource relationships in the reverse message relationships described above. That is, in the relationship between Msg2 and Msg3, and between "R2D transmission" and "D2R transmission," Msg3 (or "D2R transmission") may be performed on the transmission frequency channel associated with the time slot in which Msg2 (or "R2D transmission") was successfully received.

[0162] In another example of operation according to the first embodiment, firstly, a reader device (e.g., reader device 400) receives a D2R message from an ambient IoT device (e.g., ambient IoT device 300). Secondly, in response to receiving the D2R message, the reader device transmits an R2D message to the ambient IoT device in a time slot linked to the transmission frequency channel of the D2R message.

[0163] As a result, for example, even when the reader device 400 receives multiple D2R messages transmitted from multiple ambient IoT devices 300, it can transmit multiple R2D messages corresponding to the multiple D2R messages using each slot associated with each transmission frequency channel of the D2R messages. The ambient IoT device 300 can then receive the R2D messages received in the slot associated with the transmission frequency channel of the D2R messages as messages addressed to itself. Therefore, in other operating examples, the ambient IoT device 300 can properly receive R2D messages.

[0164] In the first embodiment, other operational examples can be implemented in the same way as in the first embodiment by replacing "Msg1" with "D2R message" and "Msg2" with "R2D message".

[0165] [Other Embodiments] In the embodiments described above, ambient IoT paging messages were explained. This was based on the premise that, for example, the perspective was that of the AS layer, which is higher than the PHY layer. For example, the ambient IoT paging message in the first embodiment may be an ambient IoT paging signal from the perspective of the PHY layer. In this case, the first embodiment can be implemented by reinterpreting the ambient IoT paging message as an ambient IoT paging signal.

[0166] The above-described operation flows can be performed not only independently, but also in combination of two or more operation flows. For example, some steps of one operation flow may be added to another operation flow, or some steps of one operation flow may be replaced with some steps of another operation flow. It is not necessary to execute all steps in each flow; only some steps may be executed. Furthermore, the order of steps in each flow may be changed as appropriate.

[0167] In the embodiments and examples described above, an example in which the base station is an NR base station (gNB) was described, but the base station may also be an LTE base station (eNB) or a 6G base station. Furthermore, 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 an IAB node. Furthermore, UE100 may be an MT (Mobile Termination) of an IAB node. That is, UE100 may be a terminal function unit (a type of communication module) for the base station to control a relay device that performs signal relay. Such a terminal function unit is referred to as an MT. Examples of multi-transmission architectures (MTs) include IAB-MT, NCR (Network Controlled Repeater)-MT, and RIS (Reconfigurable Intelligent Surface)-MT.

[0168] Furthermore, 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). Additionally, a network node may consist of a combination of at least a part of the core network device and at least a part of a base station.

[0169] 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 a computer-readable medium, it is possible to install the program on a computer. Here, the computer-readable medium on which the program is recorded may be a non-transient recording medium. The non-transient recording medium is not particularly limited, but may be a recording medium such as a CD-ROM and / or DVD-ROM. Alternatively, the 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 (chipset, SoC: System on a chip).

[0170] The functions realized by the above-described communication device (UE100 or network node 200, etc.) may be implemented in a circuit or processing circuit, including a general-purpose processor, application-specific processor, integrated circuit, ASICs (Application Specific Integrated Circuits), CPU (a Central Processing Unit), conventional circuitry, and / or a combination thereof, programmed to realize the described functions. The processor includes transistors and / or other circuits and is considered a circuit or processing circuit. The processor may also be a programmed processor that executes a program stored in memory. In this specification, circuit, unit, and means are hardware programmed to perform or execute the functions described herein. Such hardware may be any hardware disclosed herein, or any hardware known to be programmed to perform or execute the functions described herein. If such hardware is a processor that is considered to be of the type of circuit, such circuit, means, or unit is a combination of hardware and software used to constitute such hardware and / or processor.

[0171] The phrases “based on” and “depending on / in response to” as used in this disclosure do not mean “based solely on” or “in response solely” unless otherwise specified. “Based on” means both “based solely on” and “at least partially on.” Similarly, “depending” means both “at least partially on” and “at least partially on.” The terms “include,” “comprise,” and variations thereof do not mean that they include only the listed items, but may include only the listed items or may include additional items in addition to the listed items. Furthermore, the term “or” as used in this disclosure is not intended to mean exclusive OR. Additionally, 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 way to distinguish between two or more elements. Therefore, references to the first and second elements do not imply that only two elements may be adopted therein, or that the first element must precede the second element in any way. In this disclosure, where articles are added by translation, such as a, an, and the in English, these articles shall be plural unless it is clearly indicated from the context that they are not.

[0172] Although the embodiments have been described in detail above with reference to the drawings, the specific configuration is not limited to those described above, and various design changes can be made without departing from the gist of the invention.

[0173] This application claims priority to Japanese Patent Application No. 2024-169441 (filed on September 27, 2024), the entirety of which is incorporated into the specification of this application.

[0174] (Note) The above embodiments can be summarized as shown in the note, but the note does not limit the embodiments.

[0175] (Note 1) A communication method for use in a mobile communication system, comprising the steps of: a reader device which is a network node or user device of the mobile communication system receives a message 1 (Msg1) containing random identification information from an ambient IoT device; and the reader device, in response to receiving the Msg1, transmits a message 2 (Msg2) containing the random identification information to the ambient IoT device in a time slot linked to the transmission frequency channel of the Msg1.

[0176] (Note 2) The communication method according to Note 1, further comprising the steps of: the ambient IoT device transmitting the Msg1; and the ambient IoT device receiving the Msg2, wherein the step of receiving the Msg2 includes the step of the ambient IoT device treating the random identification information contained in the Msg2 received in a time slot associated with the transmission frequency channel used when transmitting the Msg1 as random identification information addressed to itself.

[0177] (Note 3) A communication method for use in a mobile communication system, comprising the steps of: a reader device which is a network node or user device of the mobile communication system receives a D2R (Device to Reader) message from an ambient IoT device; and the reader device, in response to receiving the D2R message, transmits an R2D (Reader to Device) message to the ambient IoT device in a time slot linked to the transmission frequency channel of the D2R message.

[0178] (Note 4) The communication method according to any one of Notes 1 to 3, further comprising the steps of: the ambient IoT device transmitting the Msg1; and the ambient IoT device receiving the Msg2 in a time slot associated with the transmission frequency channel used when transmitting the Msg1.

[0179] 1: Mobile communication system 10: Network 20: RAN 30: CN 100: UE 110: Receiving unit 120: Transmitting unit 130: Control unit 140: Wireless communication unit 200a, 200b, 200c: Network node 210: Transmitting unit 220: Receiving unit 230: Control unit 240: Network communication unit 250: Wireless communication unit 300: Ambient IoT device 310: Antenna 320: Modulator 330: Control unit 340: Memory 345: Communication unit 350: Matching network 351: RF energy harvester 352: PMU 353: Energy storage unit 354: RF BPF 355: RF envelope detector 356: BB LPF 357: Comparator 358: Baseband logic 359: Memory 360: Backscattering modulator 361: Clock generator 365: LNA 366: Baseband amplifier 367: Large frequency shifter 368: Reflection amplifier 369: Energy harvester 380: CN device 400: Reader device

Claims

1. A communication method for use in a mobile communication system, comprising: a reader device, which is a network node or user device of the mobile communication system, receiving a message 1 (Msg1) containing random identification information from an ambient IoT device; and the reader device, in response to receiving the Msg1, transmitting a message 2 (Msg2) containing the random identification information to the ambient IoT device in a time slot linked to the transmission frequency channel of the Msg1.

2. The communication method according to claim 1, further comprising: the ambient IoT device transmitting the Msg1; and the ambient IoT device receiving the Msg2, wherein the reception of the Msg2 includes the ambient IoT device treating the random identification information contained in the Msg2 received in a time slot associated with the transmission frequency channel used when transmitting the Msg1 as random identification information addressed to itself.

3. A communication method for use in a mobile communication system, comprising: a reader device, which is a network node or user device of the mobile communication system, receiving a D2R (Device to Reader) message from an ambient IoT device; and the reader device, in response to receiving the D2R message, transmitting an R2D (Reader to Device) message to the ambient IoT device in a time slot linked to the transmission frequency channel of the D2R message.

4. The communication method according to claim 1, further comprising: the ambient IoT device transmitting the Msg1; and the ambient IoT device receiving the Msg2 in a time slot associated with the transmission frequency channel used when transmitting the Msg1.

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