Communication method and reader device

Abstract

A communication method according to one embodiment of the present invention is used in a mobile communication system. The communication method has a step in which a reader device, which is a mobile communication system user device, detects an event in which a wireless resource used to communicate with an ambient Internet of Things (IoT) device is invalidated. The communication method also has a step in which the reader device continuously uses the wireless resource for a fixed time period after detecting the event.

Description

Communication method and reader device

[0001] The present disclosure relates to a communication method and a reader device 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. Technologies used in IoT include, for example, barcodes and RFID (Radio Frequency Identifier). However, barcodes and RFID cannot perform long-distance wireless communication and have difficulty supporting large-scale networks.

[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 are being conducted on the feasibility of new IoT technologies. 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 called 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 not only the cost of the IoT devices themselves but also the maintenance cost of the IoT devices, making it difficult to achieve.

[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) 3GPP TR 23.700-13 V1.0.0 (2024-10) R2-2407984

[0009] 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 user device of the mobile communication system, detecting an event that disables the wireless resources used for communication with an ambient IoT (Internet of Things) device. The communication method also includes the step of the reader device continuing to use the wireless resources for a certain period of time after detecting the event.

[0010] The reader device according to the second embodiment is a user device of a mobile communication system. The reader device has a control unit that detects an event that disables the wireless resources used for communication with an ambient IoT device. After detecting the event, the control unit continues to use the wireless resources for a certain period of time.

[0011] 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 topology of an ambient IoT device according to 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 an 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 of an ambient IoT procedure according to the first embodiment. Figure 14 is a diagram showing an example of operation according to the first embodiment.

[0012] This disclosure aims to ensure the continuity of services using ambient IoT devices.

[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] (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.

[0015] 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).

[0016] 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).

[0017] 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 consists of a CU (Central Unit) and a DU (Distribution 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.

[0018] 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.

[0019] 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.

[0020] 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.

[0021] 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.

[0022] 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.

[0023] 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.

[0024] 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 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 for 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.

[0025] 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.

[0026] 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.

[0027] 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.

[0028] 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.

[0029] 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.

[0030] Figure 4 shows the configuration of the protocol stack for the user plane's wireless interface that handles data.

[0031] 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.

[0032] 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 the 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 has been scrambled by RNTI, added to it.

[0033] The MAC layer performs data priority control, retransmission processing using Hybrid ARQ (HARQ), 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 a 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.

[0034] 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.

[0035] The PDCP layer performs header compression / decompression, encryption / decryption, etc.

[0036] 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.

[0037] Figure 5 shows the configuration of the protocol stack of the wireless interface of the control plane that handles signaling (control signals).

[0038] 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.

[0039] 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.

[0040] 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").

[0041] (2) Ambient IoT device The mobile communication system 1 according to the embodiment supports ambient IoT devices. Hereinafter, ambient IoT devices may be simply referred to as "devices".

[0042] (2.1) Diagram 6 of the ambient IoT device overview shows an example configuration of the 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 which is a UE 100 or a network node 200. The ambient IoT device 300 may perform wireless communication within the frequency band of the mobile communication system 1.

[0043] The ambient IoT device 300 may transmit information from 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 technique 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 that can read information from its internal memory or write information to its internal memory by using the backscattering communication function. In this case, the ambient IoT device 300 may receive a transmitted radio wave with modulated information and extract the information by demodulating the received radio wave.

[0044] The ambient IoT device 300 may be a battery - less IoT device. In this case, the ambient IoT device 300 converts the received radio wave into energy (specifically, electric power) and operates using this energy. The ambient IoT device 300 may use something other than radio waves as an energy source. For example, it may convert light, heat, magnetism, vibration, or sound, etc. into energy. Generally, such energy conversion is called environmental power generation (energy harvesting). Well - known techniques may be used for environmental power generation itself. Thus, the ambient IoT device 300 may have an environmental power generation 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 electric power obtained by the environmental power generation function. The ambient IoT device 300 may be a wireless tag.

[0045] 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.

[0046] The antenna 310 receives an unmodulated carrier wave. Hereinafter, the unmodulated carrier wave is called CW (Continuous Wave). The antenna 310 converts the received CW into a received signal and outputs the received signal to the modulator 320. Also, the antenna 310 reflects the CW according to the transmission signal output from the modulator 320 and transmits a reflected wave. Hereinafter, the reflected wave is called BS (Back Scattering or Back Scatter). The antenna 310 performs BS transmission.

[0047] 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. Further, the modulator 320 may demodulate the received signal from the antenna 310 in the modulator to acquire data 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, 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 the 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 constituted by a transistor. Alternatively, the switch may be a mechanical switch that can be physically switched on or off.

[0048] The control unit 330 may have an environmental power generation function of converting the received signal received from the modulator 320 into electric power. The control unit 330 may control the modulator 320 and the memory 340 using the electric power as the driving power of the ambient IoT device 300. Further, the control unit 330 reads the information stored in the memory 340 and controls the modulator 320 to transmit the 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, make the reflectivity 100% or 0%), and can output the 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 the transmission signal corresponding to a plurality of 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.

[0049] 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.

[0050] 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.

[0051] (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".

[0052] 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.

[0053] 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.

[0054] 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.

[0055] 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.

[0056] (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".

[0057] "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.

[0058] "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.

[0059] "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.

[0060] Figure 8 is a diagram showing an example configuration of the ambient IoT device 300 of "Device 1" according to the first embodiment.

[0061] 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.

[0062] 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.

[0063] 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.

[0064] 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.

[0065] The energy storage unit 353 stores energy from the RF energy harvester 351.

[0066] 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.

[0067] 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.

[0068] 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.

[0069] 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.

[0070] The baseband logic 358 includes functional blocks such as encoders, decoders, and controllers.

[0071] 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.

[0072] 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).

[0073] The clock generator 361 generates the necessary clock signals within the device.

[0074] 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.

[0075] Figure 9 is a diagram showing an example configuration of the ambient IoT device 300 of "device 2a" according to the first embodiment.

[0076] 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.

[0077] 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.

[0078] The baseband amplifier 366 amplifies the baseband signal output from the RF envelope detector 355, improving the signal strength.

[0079] 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).

[0080] 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.

[0081] 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.

[0082] (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.

[0083] 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.

[0084] 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").

[0085] 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").

[0086] 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.

[0087] 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.

[0088] 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).

[0089] (3) Operation of the mobile communication system The operation of the mobile communication system 1 having the ambient IoT device 300 will be described.

[0090] (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. 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.

[0091] 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.

[0092] 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.

[0093] 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.

[0094] 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.

[0095] 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).

[0096] Step S2: In response to receiving a service request, the reader device 400 sends an ambient IoT paging message (ambient IoT paging message) to the ambient IoT device 300, similar to a conventional paging message. The ambient IoT paging message may be a message that initiates communication between the reader device 400 and the ambient IoT device 300. Alternatively, the A-IoT paging message may be a call message (or trigger message) that initiates a call (or trigger) to the ambient IoT device 300.

[0097] Firstly, ambient IoT paging messages include 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 are also different types of device identification information, such as a "group ID" (group identification information) that identifies the group to which the ambient IoT devices belong. Furthermore, there is a type of device identification information called "ALL" (all 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".

[0098] Secondly, the ambient IoT paging message 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).

[0099] Thirdly, ambient IoT paging messages may include R2D commands. R2D commands represent commands sent from the reader device to the ambient IoT device 300. R2D commands are used in the case of "command" services, and the command included in the service request (step S1) may be an R2D command.

[0100] The ambient IoT paging message may also be an initial trigger message. An initial trigger message is, for example, a message that includes an ambient IoT device that needs to respond to a service request. The reader device 400 can use the ambient IoT paging message as an initial trigger message to call the ambient IoT device 300.

[0101] The ambient IoT device 300 receives an ambient IoT paging message. The ambient IoT device 300 determines whether it successfully received the ambient IoT paging message. 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 message was successfully received.

[0102] 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.

[0103] 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 message (step S2), a D2R message is sent (step S9).

[0104] In step S3, the ambient IoT device 300 determines and / or selects a resource (or access opportunity).

[0105] 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.

[0106] 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.

[0107] 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.

[0108] 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).

[0109] 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.

[0110] 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.

[0111] Step S8: The reader device 400 sends an R2D message to the ambient IoT device 300. The R2D message may include an R2D command.

[0112] 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).

[0113] Step S10: The reader device 400 sends a Subsequent Ambient IoT paging message (subsequent Ambient IoT paging message) to the Ambient IoT device 300. The Subsequent Ambient IoT paging message is, for example, a message associated with the same service request as the Ambient IoT paging message (Step S2), and is a message that follows the said Ambient IoT paging message.

[0114] (3.2) Topology 2 Figure 12 shows an example of the configuration of topology 2 according to the first embodiment.

[0115] 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.

[0116] 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.

[0117] (4) Communication method according to the first embodiment Next, a communication method according to the first embodiment will be described.

[0118] In 3GPP, the following three points have been agreed upon regarding the wireless resources used for communication between the reader device 400 (UE100) and the ambient IoT device 300 in topology 2.

[0119] A1) The dedicated resource is configured on the reader device 400 (UE100) using dedicated signaling, and a mechanism for shared wireless resources among multiple reader devices 400 (UE100) is not supported; A2) As long as the wireless resource configuration is valid, the execution of ambient IoT procedures is permitted; A3) The wireless resource can be (re)configured by RRC reconfiguration (including handover procedures, RRC re-establishment, etc.).

[0120] As shown in A2) above, as long as the wireless resource (dedicated resource) is active, the reader device 400 (UE100) can communicate with the ambient IoT device 300. Conversely, if the wireless resource is not active, the reader device 400 (UE100) cannot communicate with the ambient IoT device 300.

[0121] However, if, for example, an RLF (Radio Link Failure) occurs in the communication between the reader device 400 (UE100) and the network node 200, the wireless resources used for communication between the reader device 400 (UE100) and the ambient IoT device 300 become invalid, and communication with the ambient IoT device 300 becomes impossible, which is not necessarily desirable. If the reader device 400 (UE100) loses communication with the ambient IoT device 300, it is conceivable that the core network device (CN device) 380 may consider this a service interruption using the ambient IoT device 300 and have to reconfigure the service from scratch. Such a situation is not necessarily desirable when considering the continuity of services using the ambient IoT device 300.

[0122] Therefore, the objective of the first embodiment is to ensure the continuity of services using the ambient IoT device 300.

[0123] Therefore, in the first embodiment, firstly, a reader device (e.g., reader device 400), which is a user device (e.g., UE 100) of the mobile communication system, detects an event that disables the wireless resources used for communication with an ambient IoT device (e.g., ambient IoT device 300). Secondly, after the reader device detects the event, it continues to use the wireless resources for a certain period of time.

[0124] Thus, even if an event occurs that disables the wireless resources used for communication with the ambient IoT device 300, the UE100 can continue to use those wireless resources for a certain period of time. Therefore, ambient IoT procedures that were started before the event occurred can also be continued for a certain period of time. This makes it possible to ensure the continuity of services using the ambient IoT device 300, for example.

[0125] Here, we will describe the procedure related to ambient IoT according to the first embodiment (ambient IoT procedure).

[0126] (5) Diagram 13 of the ambient IoT procedure according to the first embodiment is a diagram showing an example of the ambient IoT procedure according to the first embodiment.

[0127] As shown in Figure 13, an example of an ambient IoT procedure is the following:

[0128] - Ambient IoT paging procedure; - Paging round procedure; - R2D Round Trigger procedure (or Access Round procedure); - R2D Trigger procedure (or Access Opportunity procedure); - Subsequent Ambient IoT paging procedure; - Data Transfer procedure.

[0129] An ambient IoT paging procedure is a series of procedures initiated, for example, by the sending (or receiving) of an ambient IoT paging message. As shown in Figure 13, the ambient IoT paging procedure may be a series of procedures performed during the period leading up to a Subsequent ambient IoT paging message associated with the same service request. This procedure may also be called a paging ground procedure. A procedure initiated by a Subsequent ambient IoT paging message may also be called a paging ground procedure. An ambient IoT procedure may consist of one or more paging ground procedures. As shown in Figure 13, the ambient IoT paging procedure may include, for example, an R2D round trigger procedure and an R2D trigger procedure. Alternatively, the ambient IoT paging procedure may include a data transfer procedure. Alternatively, the ambient IoT paging procedure may include a Subsequent ambient IoT paging procedure.

[0130] An R2D round trigger procedure is a series of procedures initiated by the transmission (or reception) of an R2D round trigger message. The R2D round trigger message may include resources (access opportunities) used for communication with the ambient IoT device 300. The R2D round trigger procedure may also be a series of procedures that continue until the communication using those resources is completed. The R2D round trigger procedure may include an R2D trigger procedure. The R2D round trigger procedure may also be called an access round procedure. The R2D round trigger message may include an access round indication that instructs the access round procedure.

[0131] An R2D trigger procedure is a series of procedures initiated by the transmission (or reception) of an R2D trigger message. The ambient IoT device 300 may, upon receiving an R2D trigger message, communicate with the reader device 400 using a resource selected from its allocated resources. The R2D trigger procedure may also be called an access opportunity procedure. The R2D trigger message may include an access opportunity indication that instructs the access opportunity procedure.

[0132] The Subsequent Ambient IoT Paging Procedure is a procedure initiated by the transmission (or reception) of a Subsequent Ambient IoT Paging Message. As described above, a Subsequent Ambient IoT Paging Message is a message associated with the same service request as an Ambient IoT Paging Message. For example, an Ambient IoT device 300 that fails to communicate with the reader device 400 in the Ambient IoT Paging Procedure can use a Subsequent Ambient IoT Paging Message to communicate with the reader device 400.

[0133] The data transfer procedure is a procedure relating to data transfer between the reader device 400 and the ambient IoT device 300. The data transfer procedure may be a series of procedures for "Write Command". The data transfer procedure may also be a series of procedures for "Read Command". For example, the data transfer procedure may be included in the R2D trigger procedure in Figure 13. That is, the data transfer procedure may be a series of procedures from the transmission of an R2D message (R2D trigger message) containing a command to the transmission of a D2R message containing a response to the command.

[0134] Other ambient IoT procedures may include, for example, random access procedures to the ambient IoT device 300.

[0135] In the first embodiment, even if an event occurs that causes a wireless resource used for communication with the ambient IoT device 300, such as an RLF, to become invalid, the ambient IoT procedure currently in progress can continue to run by using the wireless resource for a certain period of time, thereby ensuring service continuity.

[0136] (6) Example of operation according to the first embodiment An example of operation according to the first embodiment will be described.

[0137] Figure 14 is a diagram illustrating an example of operation according to the first embodiment.

[0138] As shown in Figure 14, in step S20, the receiving unit (receiving unit 110) of the reader device 400 (UE 100) receives the wireless resource settings for ambient IoT (communication) transmitted from the network node 200. The wireless resource may consist of a time domain and a frequency domain. The wireless resource may be a dedicated resource individually allocated to the reader device 400 (UE 100). The wireless resource settings may be transmitted by individual signaling. The individual signaling may be an RRC message (for example, an RRC Reconfiguration message). The control unit (control unit 130) of the reader device 400 (UE 100) can utilize the wireless resource as an ambient IoT resource based on the wireless resource settings. In the following, wireless resources for ambient IoT may be referred to as "ambient IoT resources."

[0139] In step S21, the receiving unit (receiving unit 110) of the reader device 400 (UE 100) receives a service request transmitted from the CN device 380. The AS layer of the reader device 400 (UE 100) may receive the service request from the CN device 380 via a higher layer above the AS layer. The service request may be for an "inventory" service. The service request may be for a "command" service. Alternatively, the service request may be for a service (or command) such as "Write", "Read", or "Disable".

[0140] In step S22, the control unit (control unit 130) of the reader device 400 (UE 100), upon receiving a service request (step S21), starts communication with one or more ambient IoT devices 300 using ambient IoT resources (step S20). Specifically, the control unit (control unit 130) of the reader device 400 (UE 100) executes the ambient IoT procedure described above. The ambient IoT procedure may be as follows:

[0141] - Ambient IoT paging procedure; - Subsequent ambient IoT paging procedure; - Paging round procedure; - R2D round trigger procedure (or access round procedure); - R2D trigger procedure (or access opportunity procedure); - Random access procedure to ambient IoT device 300; - Data transfer procedure to ambient IoT device 300.

[0142] In step S23, the control unit (control unit 130) of the reader device 400 (UE100) detects an event (occurrence) that disables the ambient IoT resource. This event occurs on the Uu link side between the reader device 400 (UE100) and the network node 200.

[0143] Firstly, the event may also occur when the wireless resource setting is deleted or modified by an RRC Reconfiguration message received from a network node. In this case, since the ambient IoT resource set in step S20 is explicitly instructed to be deleted or modified, this event is considered to indicate the invalidation of the ambient IoT resource. The control unit (control unit 130) of the reader device 400 (UE100) may detect the event when it receives an RRC Reconfiguration message containing information indicating the deletion or modification of the wireless resource setting.

[0144] Secondly, the event may be the execution of a handover procedure or a cell reselection procedure. When a handover procedure or a cell reselection procedure is executed, the reader device 400 (UE100) will move to a different network node (or cell) than the network node 200 (cell) where the ambient IoT resource is configured. Therefore, in such cases, the event is set to disable the ambient IoT resource. The handover procedure is started, for example, when a measurement report message is sent in response to the trigger of an event indicated in the measurement configuration (ReportConfigNR). Therefore, the control unit (control unit 130) of the reader device 400 (UE100) may detect the event by detecting the event or by detecting the transmission of the measurement report message. Alternatively, the reader device 400 (UE100) may detect the event in response to receiving an RRC Reconfiguration with sync message (handover command) or a Cell Switch Command MAC CE from a network node 200 (or its cell). Alternatively, the reader device 400 (UE100) may detect the event in response to executing a handover (or cell switch) process. The execution of the handover (cell switch) process may be performed when the conditions (event) of a conditional handover (or conditional LTM) are met. Furthermore, the cell reselection procedure may also be triggered, for example, when the cell reselection criteria are met, and an RRC setup message is sent. Therefore, the control unit (control unit 130) of the reader device 400 (UE100) may detect the event by detecting that the criteria are met or by detecting the transmission of the message.

[0145] Thirdly, the event may also be a declaration of Radio Link Failure (RLF) in the Uu link. For example, in situations where an RLF is detected in the Uu link between the reader device 400 (UE100) and the network node 200, it is advisable to reschedule. Therefore, when an RLF is declared, it is considered equivalent to disabling the ambient IoT resource. Note that an RLF is declared, for example, when the AS of the reader device 400 (UE100) receives out-of-sync notifications from the lower layer n310 times consecutively, and then does not receive in-sync notifications from the lower layer n311 times consecutively before the timer T310 expires. The control unit (control unit 130) of the reader device 400 (UE100) may detect the event when an RLF is declared.

[0146] Fourth, the event may also indicate that the RRC Re-establishment procedure has been executed. The RRC Re-establishment procedure is performed to restore the RRC connection when an RLF or similar event occurs in the Uu link. Therefore, as with the case of an RLF, it is advisable to disable the ambient IoT resource set in step S20. The RRC Re-establishment procedure is initiated by the detection of an RLF, a Hand Over Failure (HOF), etc. Therefore, the control unit (control unit 130) of the reader device 400 (UE100) may detect the event when it detects the start trigger of the RRC Re-establishment procedure or when it detects the transmission of an RRC Re-establishment Request message.

[0147] Fifth, the event may also occur when the reader device 400 (UE100) moves outside the coverage of the network node 200 (the cell housed within it). This is because, if the reader device 400 (UE100) moves outside the coverage of the network node 200, it is not possible to communicate with the network node 200, and therefore the ambient IoT resources configured by the network node 200 should be disabled. The control unit (control unit 130) of the reader device 400 (UE100) may detect the event when it detects that the quality of the wireless signal received from the network node 200 that configured the ambient IoT resources (step S20) falls below a predetermined threshold.

[0148] Sixth, the event may also be the expiration of the validity timer of the ambient IoT resource. A validity timer may also be set for wireless resources, and if the validity timer expires, the wireless resource basically cannot be used. Therefore, in the first embodiment, the event is defined as an event that disables the ambient IoT resource. The control unit (control unit 130) of the reader device 400 (UE100) may detect the event in response to detecting the expiration of the validity timer.

[0149] Seventh, the event may also indicate that the reader device 400 (UE100) has stopped or suspended (interrupted) the UL transmission to the network node 200. Upon detection of any of the above six events (events from the deletion or modification of ambient IoT resource settings by the RRC reset message to the expiration of the validity period timer), the reader device 400 (UE100) may perform processing to stop or suspend UL transmission. Therefore, stopping or suspending UL transmission may be an event that invalidates ambient IoT resources. The control unit (control unit 130) of the reader device 400 (UE100) may detect the event in response to starting the execution of the processing.

[0150] Eighth, the event may be the stopping or suspending of the wireless bearer. In this case as well, upon detection of any of the above six events (events from the deletion or modification of ambient IoT resource settings by the RRC reset message to the expiration of the validity period timer), the reader device 400 (UE100) may perform processing to stop or suspend the wireless bearer. Therefore, stopping or suspending the wireless bearer may be one of the events that disable the ambient IoT resource. The control unit (control unit 130) of the reader device 400 (UE100) may detect the event in response to the start of execution of the processing.

[0151] In step S24, the control unit (control unit 130) of the reader device 400 (UE100) checks which ambient IoT procedure is currently running. If the ambient IoT procedure is not currently running (i.e., at the time of step S24), the control unit (control unit 130) disables the ambient IoT resource set in step S20. Disabling may also mean stopping use. Disabling may also mean suspending. Disabling may also mean discarding the setting. On the other hand, if an ambient IoT procedure is currently running, the control unit (control unit 130) considers the ambient IoT resource set in step S20 to be valid and continues to use the resource for a certain period of time. Alternatively, if an ambient IoT procedure is currently running, the control unit (control unit 130) disables the ambient IoT resource set in step S20, but as an exception, it may continue to use the resource for a certain period of time. The following explanation assumes that the ambient IoT procedure is currently running.

[0152] In step S25, the control unit (control unit 130) of the reader device 400 (UE100) continues to use ambient IoT resources for a certain period of time. Specifically, the certain period may be as follows:

[0153] Firstly, the specified period may be until an ambient IoT procedure started before (or before the event that disables the ambient IoT resource) is completed. This ambient IoT procedure may be a series of ambient IoT procedures associated with a service request received by the reader device 400 (UE100) before the event occurred (or before the event was detected). Alternatively, this ambient IoT procedure may be a series of paging procedures including an ambient IoT paging procedure and a Subsequent ambient IoT procedure associated with the same service request.

[0154] Furthermore, if the reader device 400 (UE100) receives multiple service requests, it may target the service request currently in progress. In this case, even if a service request is received, the reader device 400 (UE100) may disable the ambient IoT resources for ambient IoT procedures that have not been started at step S24 without allowing the execution of those procedures.

[0155] Alternatively, if the reader device 400 (UE100) receives multiple service requests, it may allow the execution of an ambient IoT procedure, even if it has not been started at step S24, and continue to use the ambient IoT resources for that procedure.

[0156] Secondly, the specified period may be until the paging ground procedure started before (or before the event that disables the ambient IoT resource) is completed. Alternatively, the specified period may be until just before the next paging ground procedure is started for the paging ground procedure started before the event occurred.

[0157] Thirdly, the specified period may be until the access round procedure started before (or before the event that disables the ambient IoT resource) is completed. Alternatively, the specified period may be until just before the next access round procedure is started for the access round procedure started before the event occurred.

[0158] Fourth, the specified period may be until the access opportunity procedure started before (or before the event that disables the ambient IoT resource) is completed. Alternatively, the specified period may be until just before the next access opportunity procedure is started for the access opportunity procedure started before the event occurred.

[0159] Fifth, the specified period may be until the random access procedure to the ambient IoT device that was started before (or before the event that disables the ambient IoT resource) is completed. Alternatively, the specified period may be until immediately before the next random access procedure is started for the random access procedure that was started before the event occurred.

[0160] Sixth, the specified period may be until the data transfer procedure for the ambient IoT device 300 that was started before (or before the event that disables the ambient IoT resource) is completed. Alternatively, the specified period may be until just before the next data transfer procedure is started for the data transfer procedure that was started before the event occurred.

[0161] The control unit (control unit 130) of the reader device 400 (UE100) disables the ambient IoT resource after a certain period of time has elapsed. Disabling may include stopping use, suspending, or discarding the settings. Alternatively, the control unit (control unit 130) may stop communication with the ambient IoT device 300 after a certain period of time has elapsed.

[0162] Furthermore, among the ambient IoT procedures, those that are to be used continuously (or that can be used continuously) may be set by the network node 200. Alternatively, the network node 200 may set the period for which a procedure is to be used continuously. The network node 200 may perform this setting using RRC messages (e.g., RRC reconfiguration messages), or it may be set in step S20 using setting information along with the ambient IoT resource setting. Alternatively, the core network device 380 (or a higher layer) may perform this setting using a predetermined message (e.g., a message from a newly defined layer for ambient IoT (e.g., the ambient IoT layer)).

[0163] In step S26, the transmitting unit (transmitting unit 120) of the reader device 400 (UE 100) transmits a response to the service request (step S21) to the CN device 380. The AS layer of the reader device 400 (UE 100) may transmit the response to the CN device 380 via a higher layer. The response may include the result of the ambient IoT procedure. For example, if the service request is "Read", the response may include data read from the memory 340 of the ambient IoT device 300.

[0164] [Other Embodiments] The above-described operation flows are not limited to being performed separately and independently; two or more operation flows can be combined and performed. 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. Also, the order of steps in each flow may be changed as appropriate.

[0165] 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.

[0166] 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.

[0167] 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).

[0168] 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.

[0169] 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.

[0170] 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.

[0171] This application claims priority to Japanese Patent Application No. 2024-194413 (filed November 6, 2024), the entirety of which is incorporated into the specification of this application.

[0172] (Note) The above embodiments can be summarized as shown in the note, but the note does not limit the embodiments.

[0173] (Note 1) A communication method for use in a mobile communication system, comprising the steps of: a reader device, which is a user device of the mobile communication system, detecting an event that disables a wireless resource used for communication with an ambient IoT (Internet of Things) device; and the reader device, after detecting the event, continuing to use the wireless resource for a certain period of time.

[0174] (Note 2) The communication method described in Note 1, wherein the event is any of the following: the setting of the radio resource is deleted or changed by an RRC Reconfiguration message received from the network node; a handover procedure or cell reselection procedure is executed; a Radio Link Failure (RLF) is declared in the communication between the reader device and the network node; an RRC Restabilize procedure is executed; the reader device moves out of the coverage of the network node; the validity timer of the radio resource expires; the uplink transmission of the reader device to the network node is stopped or suspended; or the reader device stops or suspends the radio bearer.

[0175] (Note 3) The communication method described in Note 1 or Note 2, wherein the aforementioned period is the time until the ambient IoT procedure started before the event detection is completed.

[0176] (Note 4) The communication method according to any one of Notes 1 to 3, wherein the ambient IoT procedure is until the ambient IoT procedure associated with the service request received by the reader device before the event detection is completed, until the paging round procedure started before the event detection is completed, until the access round procedure started before the event detection is completed, until the access occasion procedure started before the event detection is completed, until the ambient IoT paging or Subsequent ambient IoT paging started before the event detection is completed, until the random access procedure to the ambient IoT device started before the event detection is completed, and until the data transfer to the ambient IoT device started before the event detection is completed.

[0177] (Note 5) A reader device which is a user device of a mobile communication system, having a control unit that detects an event that disables a wireless resource used for communication with an ambient IoT device, wherein the control unit continues to use the wireless resource for a certain period of time after detecting the event.

[0178] 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 200: 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 user device of the mobile communication system, detecting an event that disables wireless resources used for communication with an ambient IoT (Internet of Things) device; and the reader device continuing to use the wireless resources for a certain period of time after detecting the event.

2. The communication method according to claim 1, wherein the event is any of the following: the setting of the radio resource is deleted or changed by an RRC Reconfiguration message received from a network node; a handover procedure or cell reselection procedure is executed; a Radio Link Failure (RLF) is declared in the communication between the reader device and the network node; an RRC Restabilize procedure is executed; the reader device moves out of the coverage of the network node; the validity timer of the radio resource expires; the uplink transmission of the reader device to the network node is stopped or suspended; or the reader device stops or suspends the radio bearer.

3. The communication method according to claim 1, wherein the specified period is the period until the ambient IoT procedure started before the event detection is completed.

4. The communication method according to claim 3, wherein the ambient IoT procedure is until the ambient IoT procedure associated with a service request received by the reader device before the event detection is completed; until the paging round procedure started before the event detection is completed; until the access round procedure started before the event detection is completed; until the access occasion procedure started before the event detection is completed; until ambient IoT paging or Subsequent ambient IoT paging started before the event detection is completed; until the random access procedure to the ambient IoT device started before the event detection is completed; and until the data transfer to the ambient IoT device started before the event detection is completed.

5. A reader device which is a user device of a mobile communication system, having a control unit that detects an event that disables a wireless resource used for communication with an ambient IoT device, wherein the control unit continues to use the wireless resource for a certain period of time after detecting the event.

Images