Device, communication method, and communication system

Abstract

This device comprises a wireless communication unit and a control unit that, when the wireless communication unit receives a DL signal or a relay signal thereof, controls the wireless communication unit to transmit an outgoing signal to a plurality of first devices after a first time has elapsed, the first time including a waiting time unique to the device.

Description

Device, communication method and communication system

[0001] The present disclosure relates to a device, a communication method, and a communication system.

[0002] Short-distance wireless communication such as RFID has become widespread, and various related technologies have been proposed (see, for example, Patent Document 1).

[0003] JP 2024-019192 A

[0004] It is possible to expand the overall communication range (coverage) by placing multiple devices that communicate with each other via short-range wireless communication in multiple areas (multi-zones). However, in this case, the communication ranges of the areas overlap, causing interference there, i.e., multi-zone interference, to become a problem.

[0005] One aspect of the present disclosure suppresses multi-zone interference.

[0006] A device according to one aspect of the present disclosure comprises a wireless communication unit and a control unit that controls the wireless communication unit so that, when the wireless communication unit receives a DL signal or its relay signal, the wireless communication unit transmits an outgoing signal to a plurality of first devices after a first time has elapsed, wherein the first time includes a waiting time specific to the device.

[0007] A communication method according to one aspect of the present disclosure includes, when a device receives a DL signal or its relay signal, transmitting an outgoing signal to a plurality of first devices after a first time has elapsed, the first time including a waiting time specific to the device.

[0008] A communication system according to one aspect of the present disclosure comprises a plurality of first devices, a plurality of second devices each communicating with a corresponding plurality of first devices among the plurality of first devices, and an upper level device communicating with some of the second devices among the plurality of second devices, wherein when the second devices receive a DL signal from the upper level device or a relay signal of a DL signal from another second device, the second devices transmit an outgoing signal to the corresponding plurality of first devices after a first time has elapsed, the first time including a waiting time specific to the second device.

[0009] 1 is a diagram illustrating an example of a schematic configuration of a communication system 100 according to an embodiment. FIG. 1 is a block diagram illustrating an example of a schematic configuration of a device 1. FIG. 2 is a block diagram illustrating an example of a schematic configuration of a device 2. FIG. 2 is a diagram illustrating an example of signals transmitted and received in the communication system 100. FIG. 3 is a diagram illustrating an example of a signal transmission frequency. FIG. 4 is a diagram illustrating an example of calculation of a waiting time Tw. FIG. 5 is a diagram illustrating an example of waiting time T for a plurality of devices 2. FIG. 6 is a diagram illustrating an example of transmission of an outgoing signal 21. FIG. 7 is a diagram illustrating an example of transmission of a relay signal 22. FIG. 8 is a diagram illustrating an example of operation (communication method) of the communication system 100. FIG. 9 is a diagram illustrating an example of operation (communication method) of the communication system 100. FIG. 10 is a sequence diagram illustrating an example of processing (communication method) executed in the communication system 100. FIG. 11 is a sequence diagram illustrating an example of processing (communication method) executed in the communication system 100. FIG. 12 is a sequence diagram illustrating an example of processing (communication method) executed in the communication system 100. FIG. 13 is a diagram illustrating an example of a signal format. FIG. 14 is a diagram illustrating an example of application to a greenhouse. FIG. 15 is a diagram illustrating an example of application. FIG. 16 is a block diagram illustrating an example of a schematic configuration of a base station 4. FIG. 17 is a block diagram illustrating an example of a schematic configuration of a terminal device 5.

[0010] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. In the following embodiments, the same elements are designated by the same reference numerals, and redundant description will be omitted.

[0011] The present disclosure will be described in the following order: 0. Introduction 1. Embodiment 2. Signal Format Example 3. Application Example 4. Application Example 5. Conclusion 6. Configuration Example of Base Station and Terminal Device

[0012] 0. Introduction Near-field wireless communication such as RFID (Radio Frequency Identification) has a narrow communication range of only a few meters, and the coverage is narrow. This problem becomes even more pronounced in the case of battery-less devices.

[0013] When wireless communication using, for example, backscattering is performed between an RF reader / writer and multiple RF tags (also called IC tags, etc.), conventionally, time-division control was used to prevent interference between the signal transmissions of the multiple RF tags. However, in recent years, even if interference occurs when multiple RF tags simultaneously transmit signals, it has become possible to remove the interference by signal processing on the RF reader / writer side. For example, MSMA (Multiple Subcarrier Multiple Access) technology is known.

[0014] To expand the application range, it is conceivable to divide the entire application range into multiple areas (multi-zones) and provide a reader / writer and multiple corresponding RF tags in each area. However, in this case, the coverage areas of the multiple reader / writers overlap, and interference therein becomes a problem. For example, such multi-zone interference can be addressed by the disclosed technology.

[0015] 1 is a diagram showing an example of a schematic configuration of a communication system 100 according to an embodiment. The communication system 100 includes two types of devices and an upper level device 3.

[0016] The first type of device (first device) of the two types of devices is referred to and illustrated as device 1. The second type of device (second device) is referred to and illustrated as device 2. The communication system 100 includes two or more devices 1 and two or more devices 2. The number of devices 1 is greater than the number of devices 2. In other words, the number of devices 2 is less than the number of devices 1.

[0017] 1 illustrates six devices 2 as a plurality of devices 2. In order to distinguish between the devices 2, they are referred to as device 2-1 to device 2-6 in the figure. When there is no need to distinguish between them, they are simply referred to as device 2.

[0018] A plurality of devices 1 capable of wireless communication with one device 2 are provided (placed) for one device 2. The area (zone) where wireless communication is possible is called an area 9 and is illustrated. There are the same number of areas 9 (multi-zones) as the number of devices 2. The areas 9 corresponding to devices 2-1 to 2-6 are called areas 9-1 to 9-6 and are illustrated. When no particular distinction is made between these, they are simply referred to as areas 9.

[0019] At least some of the devices 2 among the plurality of devices 2, for example, devices 2 in adjacent areas 9, can wirelessly communicate with each other. All of the devices 2 can wirelessly communicate with each other directly or indirectly via other devices 2.

[0020] In one area 9, a device 2 and multiple devices 1 located around it form, for example, a star-type network. Multiple devices 2 corresponding to multiple areas 9 form, for example, a partial mesh-type network. A network is constructed that covers all devices 1 and 2. The devices 1 and 2 function as components of the network, for example, as nodes.

[0021] Device 1 and device 2 can also be called so-called IoT devices. As will be described later, device 1 and device 2 are used to collect data, and device 1 and device 2, which are installed in various locations for this purpose, can also be called AIoT (Ambient IoT) devices.

[0022] The entirety of the multiple areas 9 constitutes the application range of the communication system 100. By adjusting the number and arrangement of the devices 1 and 2, the application range of the communication system 100 can be freely changed.

[0023] A short-range wireless communication technology, specifically an RFID technology or a technology based thereon, is used for wireless communication between device 1 and device 2. Device 1 operates like an RF tag (also called an IC tag, etc.), and device 2 operates like an RF reader / writer.

[0024] The power consumption of device 1 is generally assumed to be smaller than that of device 2. In other words, the power consumption of device 2 is assumed to be larger than that of device 1. For example, the peak power consumption of device 1 may be in the range of about 1 μW to about several hundred μW. On the other hand, the peak power consumption of device 2 may be at least about several hundred μW. Examples of the configurations of device 1 and device 2 will be described with reference to FIGS. 2 and 3.

[0025] 2 is a block diagram showing an example of a schematic configuration of device 1. Device 1 includes a wireless communication unit 101, a control unit 102, and a storage unit 103. These functions may be realized by hardware design (e.g., an IC, a module, etc.), and some functions may be realized by software design.

[0026] The wireless communication unit 101 receives and transmits wireless signals. The wireless communication unit 101 includes various RF components (e.g., antennas, filters, etc.) required for transmitting and receiving wireless signals. The wireless communication unit 101 also includes an energy storage component for extracting and using power from the wireless signal received from the device 2. Examples of the energy storage component include a resonator for energy harvesting, a rectifier, a large-capacity capacitor (supercapacitor), etc.

[0027] The control unit 102 controls the entire device 1 by controlling other elements of the device 1. The control by the control unit 102 may include various types of processing such as signal processing and arithmetic processing. Unless otherwise specified, the device 1 operates under the control of the control unit 102.

[0028] The storage unit 103 stores data. The meaning of data may be interpreted as information, and may be interpreted as appropriate within a consistent range. An example of data stored in the storage unit 103 is data d1. The data d1 corresponds to data to be read (read) by an RF reader / writer. Any data that can be acquired by the device 1 can be data d1.

[0029] 3 is a block diagram showing an example of a schematic configuration of device 2. Device 2 includes a wireless communication unit 201, a control unit 202, and a storage unit 203. These functions may be realized by hardware design (e.g., an IC, a module, etc.), and some functions may be realized by software design.

[0030] The wireless communication unit 201 receives and transmits wireless signals. Similar to the wireless communication unit 101 of the device 1 described above, the wireless communication unit 201 may include various RF components. The wireless communication unit 201 also includes an energy storage component. Examples of the energy storage component include a dedicated IC for energy harvesting, a resonator or rectifier for energy harvesting, a rectenna IC (Rectifier) ​​for receiving wireless power transmitted from an external system, and a large-capacity capacitor (supercapacitor).

[0031] The control unit 202 controls the entire device 2 by controlling other elements of the device 2. The control by the control unit 202 may include various types of processing such as signal processing and arithmetic processing. Unless otherwise specified, the device 2 operates under the control of the control unit 202.

[0032] The storage unit 203 stores data used by the device 2. Examples of the data stored in the storage unit 203 include a plurality of pieces of data d1. These pieces of data d1 are the data d1 of each of the plurality of devices 1 corresponding to the device 2, and are obtained from signals (corresponding to outgoing signals 12 described below) from each of the plurality of devices 1.

[0033] The power consumption of device 2 is generally allowed to be greater than that of device 1, and therefore the components of device 2 can be designed to have higher performance than the components of device 1. For example, the wireless communication unit 201 and control unit 202 of device 2 may have a function to independently generate a signal (signal generation function) or a function to amplify a signal (signal amplification function). For this purpose, a signal generator, amplifier, etc. that consumes a certain amount of power may be mounted in device 2.

[0034] Furthermore, the wireless communication unit 201 and the control unit 202 of the device 2 may have a function (for example, the MSMA technology described above) to distinguish and process each signal even when signals are simultaneously received from multiple devices 1. For this purpose, the device 2 may be equipped with a signal processing circuit or the like that consumes a certain amount of power.

[0035] As described above, device 2 independently generates, transmits, receives, processes, etc. signals, but is significantly limited in power consumption, functionality, etc. compared to a general device (such as terminal device 5). For example, device 2 may not be able to use a crystal oscillator. A simple oscillator with lower accuracy than a crystal oscillator will be used, but the low clock accuracy makes clock-based synchronization difficult.

[0036] In one embodiment, even when using the above-described simple oscillator, a modulation method and synchronization establishment procedure may be adopted that can ensure synchronization with low power consumption. As an example of such a modulation method and synchronization establishment procedure, a low-power OOK (On Off Keying) modulation method, the specification of which is currently being studied in the "LP-WUS (Low Power Wake Up Signal)" topic of 3GPP (registered trademark) Release 18, is used. The LP-SS (Low Power Synchronization Signal) that is periodically transmitted from the base station (BS) and known in advance on the device 2 side, is used to realize initial synchronization establishment on the time axis (time domain) and frequency axis (frequency domain). In particular, when using the above-described modulation method and synchronization establishment procedure, it can operate with power that is relatively about two orders of magnitude smaller than the synchronization establishment procedure using SSB (Synchronization Signal Block) using the OFDM modulation method in existing 5G (NR).

[0037] 1, one device 2 having the above-described configuration and a plurality of corresponding devices 1 are provided in one region 9. A similar arrangement is performed for each of the plurality of regions 9.

[0038] Hereinafter, wireless communication will also be simply referred to as communication. Within the scope of no contradiction, communication may be appropriately interpreted as wireless communication. Furthermore, the main entity responsible for transmitting and receiving signals in device 1 is the wireless communication unit 101, and the main entity responsible for controlling this is the control unit 102. The main entity responsible for transmitting and receiving signals in device 2 is the wireless communication unit 201, and the main entity responsible for controlling this is the control unit 202.

[0039] Furthermore, hereinafter, it is assumed that the signal transmitted from device 2 to device 1 and the signal transmitted from device 2 to device 1 are both transmitted signals. A transmitted signal from one of device 1 and device 2 in the same area 9 is received by the other device. That is, a transmitted signal from device 2 is received by each of the corresponding multiple devices 1. A transmitted signal from each of the multiple devices 1 is received by device 2. Device 1 receives the transmitted signal from device 2, operates using the power obtained therefrom, and transmits a transmitted signal to device 2. It can also be said that device 1 operates using the backscatter method.

[0040] The higher-level device 3 communicates with at least some of the devices 2 (also referred to as communication target devices 2) among the plurality of devices 2. In the example shown in FIG. 1 , the higher-level device 3 includes a base station 4 and a terminal device 5.

[0041] As the name suggests, the base station 4 communicates wirelessly with terminal devices 5, which are mobile station devices located within its coverage area. The terminal devices 5 are terminal devices such as smartphones, and are also referred to as UE (User Equipment). Specific configuration examples of the base station 4 and the terminal devices 5 will be described later with reference to FIGS. 17 and 18 .

[0042] 1, of the base station 4 and the terminal devices 5, terminal device 5 communicates with device 2. As such terminal devices 5, two terminal devices 5 are illustrated, designated by the symbols terminal device 5-1 and terminal device 5-4. Terminal device 5-1 communicates with device 2-1. Terminal device 5-4 communicates with device 2-4.

[0043] The higher-level device 3 may include only one of the base station 4 and the terminal device 5. When the higher-level device 3 includes only the base station 4, the base station 4 communicates with the device 2 as the communication target (direct network communication). When the higher-level device 3 includes only the terminal device 5, the terminal device 5 communicates with the device 2 as the communication target (direct communication between the terminal device 5 and the device 2). When the higher-level device 3 includes both the base station 4 and the terminal device 5, the base station 4 may communicate with the device 2 as the communication target, or the terminal device 5 may communicate with the device 2 as the communication target. Furthermore, the base station 4 may communicate with the device 2 via the terminal device 5, in which case the base station 4 communicates with the terminal device 5 and the base station 4 communicates with the device 2 as the communication target (indirect network communication). Within the scope of no contradiction, the communication between the higher-level device 3 and the device 2 as the communication target may be interpreted as any of direct network communication, direct communication between the terminal device 5 and the device 2, and indirect network communication.

[0044] The device 2 will now be described further. The device 2 may be capable of transitioning between an awake state and a sleep state. The awake state is a state in which operations such as wireless communication can be performed in synchronization with the higher-level device 3. The sleep state is a state in which wireless communication cannot be performed immediately, but consumes less power than the awake state. In this case, the higher-level device 3 transmits a signal to the device 2 to transition the device 2 from the sleep state to the awake state.

[0045] Between the base station 4 and the terminal device 5, the base station 4 transmits an LP-WUS to the terminal device 5, and upon receiving the signal, the terminal device 5 transitions from a sleep state to an awake state. This technology is currently being studied as a topic for 3GPP Release 18. The terminal device 5 is equipped with a dedicated low-power receiver called an LP-WUR (Low Power Wake Up Receiver), which is separate from the main radio portion of the terminal device 5. The sleep state described here is generally referred to as a deep sleep state or e-DRX (Discontinuous Reception Mode). Hereinafter, the sleep state will be referred to as a deep sleep state.

[0046] The higher-level device 3 and the device 2 may be designed so that a similar technique can be applied to the higher-level device 3 and the device 2. The higher-level device 3 transmits an LP-WUS to the device 2, which is in a deep sleep state. In response to receiving the LP-WUS from the higher-level device 3, the device 2 transitions from the deep sleep state to an awake state.

[0047] A signal for receiving an LP-WUS by the device 2 in a deep sleep state is transmitted from the host device 3 to the device 2, for example, at a predetermined period. As mentioned above, this signal is also referred to as an LP-SS or the like. For example, the host device 3 periodically transmits an LP-SS to the device 2, whereby the device 2 can achieve initial synchronization establishment on the time axis (time domain) and frequency axis (frequency domain) using the known LP-SS. By subsequently receiving an LP-WUS transmitted again at a known periodic timing, accurate synchronization is established on the time axis (time domain) and frequency axis (frequency domain). Following the synchronization establishment procedure described above, a downlink signal (corresponding to a DL signal 32 described below) is transmitted from the host device 3 to the device 2. In other words, the device 2 can accurately establish synchronization and receive downlink signals by receiving the LP-SS and LP-WUS from the host device 3. Furthermore, the device 2 that has been able to accurately establish synchronization with the higher-level device 3 may relay (relay transmit) the LP-SS and LP-WUS as DL signals from the higher-level device 3 to other devices 2 that are in locations where they cannot receive the LP-SS and LP-WUS from the higher-level device 3, in order to transition them from a deep sleep state to an awake state. When the downlink signal requests the device 2 to perform an uplink operation, the device 2 transmits an uplink signal (corresponding to a UL signal 23 described below) to the higher-level device 3.

[0048] Note that the state in which the device 2 has established accurate synchronization with the higher-level device 3 may mean, more specifically, the establishment of synchronization with the base station 4. The terminal device 5 may also transition to a deep sleep state, and in that case, the base station 4 may also transmit an LP-SS and an LP-WUS to the terminal device 5.

[0049] One of the purposes of the communication system 100 having the above-described configuration is to collect data d1 from each of the multiple devices 1. To this end, various signals are transmitted and received between the higher-level device 3 and the device 2, and between the device 2 and the device 1. This will be described with reference to FIG. 4 as well.

[0050] 4 is a diagram showing an example of signals transmitted and received in the communication system 100. The higher-level device 3 transmits a DL signal 32 (downlink signal) to each of the devices 2 with which it is communicating, in this example, device 2-1 and device 2-4. The DL signal 32 is relay-transmitted (relay-transmitted) to devices 2 other than the devices with which it is communicating.

[0051] The device 2 that receives the DL signal 32 from the higher-level device 3 transmits a relay signal 22 of the DL signal 32 to another device 2. The relay signal 22 of the DL signal 32 may be a signal that includes the same data as the data included in the DL signal 32. In the example shown in Fig. 4, the relay signal 22 of the DL signal 32 is transmitted in the order from device 2-1 to device 2-2, and from device 2-2 to device 2-3, and also in the order from device 2-4 to device 2-5, and from device 2-5 to device 2-6.

[0052] The relay signal 22 transmitted from device 2-1 to device 2-2 is also referred to as relay signal 22-12. The relay signal 22 transmitted from device 2-2 to device 2-3 is also referred to as relay signal 22-23. The relay signal 22 transmitted from device 2-4 to device 2-5 is also referred to as relay signal 22-45. The relay signal 22 transmitted from device 2-5 to device 2-6 is also referred to as relay signal 22-56.

[0053] The relay signal 22 may also include a signal (e.g., bit data) indicating the number of relays. The number of relays indicates the number of relay transmissions performed until the device 2 receives the relay signal 22 of the DL signal 32, and more specifically, the number of other devices 2 through which the signal passed before receiving the relay signal 22 (the number of nodes through which the signal passed).

[0054] For example, for device 2-1 that receives DL signal 32 from higher-level device 3, there is no other device 2 that the signal passed through, so there is no relay count (for example, the relay count is treated as 0). For relay signal 22-12 from device 2-1 to device 2-2, the only other device 2 that the signal passed through is device 2-1, so the relay count is 1. For relay signal 22-23 from device 2-2 to device 2-3, the other devices 2 that the signal passed through are device 2-1 and device 2-2, so the relay count is 2. Similarly, there is no relay count for device 2-4, but for relay signal 22-45 from device 2-4 to device 2-5, the relay count is 1, and for relay signal 22-56 from device 2-5 to device 2-6, the relay count is 2.

[0055] When device 2 receives DL signal 32 or its relay signal 22, it transmits an outgoing signal 21 to corresponding devices 1 (devices 1 provided in the same area 9). In response to receiving outgoing signal 21 from device 2, device 1 transmits outgoing signal 12 to device 2.

[0056] A device 2 that is a communication target of the higher-level device 3 transmits a UL signal 23 (uplink signal) to the higher-level device 3. At this time, a UL relay signal 22 is transmitted (relayed) from a device 2 that is not a communication target of the higher-level device 3 to the communication target device 2, and the UL signal 23 is then transmitted from there to the higher-level device 3. The UL relay signal 22 may be a signal that includes data to be included in the UL signal 23.

[0057] 4, the UL relay signal 22 is transmitted in the order from device 2-3 to device 2-2, from device 2-2 to device 2-1, and from device 2-6 to device 2-5, and from device 2-5 to device 2-4. The UL signal 23 is transmitted from each of device 2-1 and device 2-4 to the higher-level device 3.

[0058] The relay signal 22 transmitted from device 2-3 to device 2-2 is also referred to as relay signal 22-32. The relay signal 22 transmitted from device 2-2 to device 2-1 is also referred to as relay signal 22-21. The relay signal 22 transmitted from device 2-6 to device 2-5 is also referred to as relay signal 22-65. The relay signal 22 transmitted from device 2-5 to device 2-4 is also referred to as relay signal 22-54.

[0059] 5 is a diagram showing an example of the transmission frequency of a signal. The transmission frequency of the DL signal 32 is a DL (downlink) frequency. The DL frequency here refers to the DL frequency in communication between the device 2 and the higher-level device 3, more specifically, in communication between the base station 4 and the device 2 or the terminal device 5. The transmission frequency of the relay signal 22 of the DL signal 32 is also a DL frequency.

[0060] The transmission frequency of the outgoing signal 21 is an UL (uplink) frequency. The UL frequency here refers to the UL frequency in communication between the device 2 and the higher-level equipment 3, more specifically, in communication between the base station 4 and the device 2 or the terminal equipment 5. The transmission frequency of the outgoing signal 12 is also an UL frequency. The transmission frequency of the UL signal 23 is also an UL frequency. The UL relay signal 22 is also an UL frequency.

[0061] Although the specific transmission frequency band is not particularly limited, it is desirable that the transmission frequency be a frequency of about several hundred MHz, which has small free space attenuation and makes it easy to obtain the desired propagation distance characteristics, for example, an FDD-compatible frequency band of FR1 (Frequency Range 1), which is a licensed band.

[0062] Returning to Fig. 4, by utilizing the transmission and reception of various signals as described above, data d1 from each of multiple devices 1 can be transmitted to and collected by the host device 3 via the device 2. However, interference may occur due to the transmission and reception of various signals. In particular, when there are multiple regions 9 corresponding to multiple devices 2 as described above with reference to Fig. 1, multi-zone interference may occur because some of the regions 9 (Fig. 1) overlap with each other.

[0063] In this embodiment, the transmission and reception of various signals are controlled to suppress (avoid, etc.) multi-zone interference. For example, the transmission of the outgoing signals 21 is controlled so that each of the multiple devices 2 transmits the outgoing signals 21 at a different time. Furthermore, the transmission of the relay signals 22 is controlled so that each of the multiple devices 2 transmits the relay signals 22 at a different time. This type of control can be considered one form of time-division control.

[0064] Specifically, when a device 2 receives the DL signal 32 or its relay signal 22, it transmits an outgoing signal 21 to the corresponding devices 1 after a certain time (which may also be referred to as a period) has elapsed. This time is referred to as a first time T1. The first time T1 of each of the devices 2 may have a different length from each other. This suppresses interference caused by the outgoing signals 21 transmitted by each of the devices 2.

[0065] Furthermore, when a device 2 receives the DL signal 32 or its relay signal 22, after a certain time has elapsed, the device 2 transmits a relay signal 22 of the DL signal 32 to another device 2. This time is referred to as the second time T2. The second times T2 of the multiple devices 2 may have different lengths. This suppresses interference caused by the relay signals 22 transmitted by each of the multiple devices 2.

[0066] The first time T1 and the second time T2 are determined based on a waiting time specific to the device 2. The waiting time is also referred to as waiting time Tw. The control unit 202 of the device 2 calculates the waiting time Tw specific to the device 2 based on information specific to the device 2. Description will also be made with reference to FIGS. 6 and 7.

[0067] 6 is a diagram showing an example of calculation of the waiting time Tw. The control unit 202 of the device 2 calculates the waiting time Tw based on information unique to the device 2. Examples of the information unique to the device 2 include a device ID and a relay count.

[0068] The device ID is an identifier that is specific (unique) to the device 2. For example, the device ID is assigned when the device 2 is manufactured. The device ID may be variable, and in that case, the device ID may be rewritten (updated) at any time. The number of relays is as described above, and is obtained, for example, from the relay signal 22, or is treated as 0 if there is no relay.

[0069] An upper limit (which may also be referred to as an allowable time) may be set for the waiting time Tw, and in this case, the control unit 202 calculates the waiting time Tw so that the waiting time Tw is equal to or less than a predetermined time. The specific value of the predetermined time may be set as appropriate depending on the specifications of the communication system 100, etc. An example of the predetermined time is approximately 10 seconds.

[0070] The algorithm used by the control unit 202 to calculate the waiting time Tw is not particularly limited. The algorithm only needs to be designed so that different waiting times T that are equal to or shorter than a predetermined time can be obtained when different input information (in this example, a device ID and a number of relays) is given. Note that only one of the device ID and the number of relays may be used, as long as a waiting time Tw specific to the device 2 can be obtained. Other information may also be used.

[0071] 7 is a diagram showing an example of waiting times T for multiple devices 2. The waiting times Tw for devices 2-1 to 2-6 are shown as waiting times Tw-1 to Tw-6. Each of the waiting times Tw-1 to Tw-6 may have a different length.

[0072] As described above, the first time T1 and the second time T2 are determined based on the waiting time Tw. For example, the first time T1 may be a time that includes the waiting time Tw, and the first times T1 of the multiple devices 2 may have different lengths. Similarly, the second time T2 may also be a time that includes the waiting time Tw, and the second times T2 of the multiple devices 2 may have different lengths.

[0073] The second time T2 may be longer than the first time T1. For example, the first time T1 may be the same as the waiting time Tw. The second time T2 may be the sum of a predetermined time (the upper limit of the waiting time Tw) and the waiting time Tw. Signal transmission based on the first time T1 and the second time T2 will be described with reference to FIGS. 8 and 9.

[0074] 8 is a diagram showing an example of transmission of the outgoing signal 21. When the device 2 receives the DL signal 32 or its relay signal 22, the device 2 transmits the outgoing signal 21 after a first time T1 has elapsed since the reception of the DL signal 32 or its relay signal 22. In this example, the first time T1 is the same as the waiting time Tw (which is equal to or shorter than the predetermined time).

[0075] Because the first time T1 of each of the multiple devices 2 has a different length, even if several devices 2 receive the DL signal 32 or its relay signal 22 at the same time, those devices 2 transmit the outgoing signal 21 at different times. For example, device 2-1 and device 2-4 shown in FIG. 4 described above may receive the DL signal 32 at the same time, but even in this case, the time at which device 2-1 transmits the outgoing signal 21 and the time at which device 2-4 transmits the outgoing signal 21 will be different times. The same can be said for the outgoing signals 21 transmitted by other devices 2. Therefore, it is possible to suppress multi-zone interference that may occur due to the outgoing signals 21 transmitted by each of the multiple devices 2.

[0076] 9 is a diagram illustrating an example of transmission of the relay signal 22. When the device 2 receives the DL signal 32 or the relay signal 22, the device 2 transmits the relay signal 22 after a second time T2 has elapsed since the reception of the DL signal 32 or the relay signal 22. In this example, the second time T2 is the sum of the predetermined time and the waiting time Tw.

[0077] Because the second time T2 of each of the multiple devices 2 has a different length, even if several devices 2 receive the DL signal 32 or its relay signal 22 at the same time, those devices 2 transmit the relay signal 22 at different times. For example, device 2-1 and device 2-4 shown in FIG. 4 described above may receive the DL signal 32 at the same time, but even in this case, the time at which device 2-1 transmits the relay signal 22 and the time at which device 2-4 transmits the relay signal 22 will be different times. The same can be said for the relay signals 22 transmitted by other devices 2. Therefore, multi-zone interference that may occur due to the relay signals 22 transmitted by each of the multiple devices 2 can be suppressed.

[0078] As a more specific example of the operation of the communication system 100, the operation of collecting data d1 from each of the multiple devices 1 will be described with reference to FIGS.

[0079] 10 and 11 are diagrams showing an example of the operation (communication method) of the communication system 100. As a premise, it is assumed that the device 2, which has been waiting in a deep sleep state, receives an LP-SS and an LP-WUS from a higher-level device 3 (e.g., a base station 4) directly or via relay transmission, and establishes synchronization with the higher-level device 3.

[0080] 10, the higher-level device 3 transmits a DL signal 32 to each of the device 2-1 and the device 2-4. The DL signal 32 transmitted here is a signal (provisioning signal) for provisioning the device 2. Provisioning means making various settings related to wireless communication. Examples of settings include initial allocation of wireless resources and initial settings related to wireless communication.

[0081] In response to receiving the DL signal 32 from the higher-level device 3, the device 2-1 transmits an outgoing signal 21 to the corresponding plurality of devices 1 after the first time T1 of the device 2-1 has elapsed. The transmitted outgoing signal 21 is a signal requesting the device 1 to transmit data d1. In response to receiving the outgoing signal 21 from the device 2-1, each of the plurality of devices 1 corresponding to the device 2-1 transmits the outgoing signal 21 to the device 2-1. The outgoing signal 21 is a signal including the data d1 of that device 1. In addition, in response to receiving the DL signal 32, the device 2-1 transmits a relay signal 22-12 to the device 2-2 after the second time T2 of the device 2-1 has elapsed.

[0082] In response to receiving the relay signal 22-12 from the device 2-1, the device 2-2 transmits an outgoing signal 21 to the corresponding devices 1 after a first time T1 for the device 2-2 has elapsed. Each device 1 transmits an outgoing signal 12 including data d1 to the device 2-2. Furthermore, the device 2-2 transmits a relay signal 22-23 to the device 2-3 after a second time T2 for the device 2-2 has elapsed.

[0083] In response to receiving relay signals 22-23 from device 2-2, device 2-3 transmits an outgoing signal 21 to the corresponding devices 1 after a first time T1 for device 2-3 has elapsed. Each device 1 transmits an outgoing signal 12 including data d1 to device 2-3. Furthermore, device 2-3 transmits a relay signal 22 to the other devices 2 after a second time T2 for device 2-3 has elapsed.

[0084] The operations of the devices 2-4 to 2-6 are similar to those of the devices 2-1 to 2-3, and therefore a description thereof will be omitted.

[0085] In this way, the data d1 of each of the multiple devices 1 is transmitted to and stored (held) in the corresponding device 2. Each of the multiple devices 2 transmits the outgoing signal 21 based on a different first time T1 and transmits the relay signal 22 based on a different second time T2, thereby suppressing multi-zone interference that may occur due to the transmission of these signals.

[0086] 11, the higher-level device 3 transmits a DL signal 32 to each of the devices 2-1 and 2-4. The DL signal 32 transmitted here is a signal (data request signal) for requesting data d1. The data request signal can also be considered a signal (DL setting signal for UL operation) that the higher-level device 3 transmits to the device 2 to cause the device 2 to transmit a UL signal 23 including the data d1.

[0087] When device 2 receives a DL signal 32 containing a data request signal or its relay signal 22, it transmits a UL relay signal 22 containing the requested data to another device 2 or transmits a UL signal 23 containing the requested data to a higher-level device 3.

[0088] Specifically, the DL signal 32 is transmitted to each device 2 by the relay transmission described above. Furthermore, by the reverse relay transmission, data d1 stored in a device 2 other than the communication target of the higher-level device 3 is transmitted to the device 2 that is the communication target of the higher-level device 3. In this example, data d1 stored in devices 2-2, 2-3, etc. is relayed to device 2-1. Data d1 stored in devices 2-5, 2-6, etc. is relayed to device 2-4.

[0089] A device 2 that is a communication target of the higher-level device 3 transmits to the higher-level device 3 an UL signal 23 that includes data d1 stored in that device 2 and data d1 obtained from a relay signal 22 of another device 2. In this example, device 2-1 transmits to the higher-level device 3 an UL signal 23 that includes data d1 stored in devices 2-1 to 2-3, etc. Device 2-4 transmits to the higher-level device 3 an UL signal 23 that includes data d1 stored in devices 2-4 to 2-6, etc.

[0090] In this way, the data d1 of each of the multiple devices 1 is transmitted to and collected by the higher-level device 3 via the multiple devices 2. Since each of the multiple devices 2 transmits the UL relay signal 22 or the UL signal 23 based on the second time T2 that is different from each other, it is possible to suppress multi-zone interference that may occur due to the transmission of these signals.

[0091] It is possible that data d1 from several devices 1 may be collected in duplicate, but in that case, the upper device 3 may deal with the problem appropriately by processing the data or the like.

[0092] An example of the operation sequence will be described with reference to FIGS. 12 and 13. FIG.

[0093] 12 and 13 are sequence diagrams showing an example of a process (communication method) executed in the communication system 100. Descriptions of content that overlap with those described above will be omitted where appropriate.

[0094] 12 shows the sequence of the operation of FIG. 10 described above. In steps S1 and S2, the plurality of devices 2 and the terminal device 5 are all waiting in a deep sleep state. In step S3, the base station 4 transmits an LP-SS and an LP-WUS to the terminal device 5 and the device 2 with which it is to communicate. By receiving the LP-SS and LP-WUS from the base station 4, the terminal device 5 and the device 2 in the deep sleep state can establish synchronization with the base station 4 and become operational (wireless communication, etc.).

[0095] In step S4, the base station 4 transmits a DL signal 32 (here, a provisioning signal) to the terminal device 5 and the device 2 to be communicated with. Provisioning is performed in the terminal device 5. In addition, the DL signal 32 is relayed between the multiple devices 2, and provisioning is performed in each device 2.

[0096] In step S5, in response to receiving the DL signal 32 or its relay signal 22 (provisioning, relay count), each of the plurality of devices 2 transmits an outgoing signal 21 (operation request) to the corresponding plurality of devices 1 and also transmits the relay signal 22 to the other devices 2. The transmission of the outgoing signal 21 and the relay signal 22 by each device 2 is performed based on the first time T1 and second time T2 of that device 2, as described above.

[0097] In step S6, in response to receiving the outgoing signal 21 from the corresponding device 2, each of the plurality of devices 1 transmits the outgoing signal 12 (data d1) to that device 2. In step S7, each of the plurality of devices 2 stores the data d1 of each of the corresponding plurality of devices 1.

[0098] Although not shown in the figure, it is assumed that thereafter, the multiple devices 2 and the terminal device 5 all transition to a deep sleep state.

[0099] 13 shows the sequence of the operation of FIG. 11 described above. In steps S11 and S12, the device 2 and the terminal device 5 are both waiting in a deep sleep state. In step S13, an LP-SS and an LP-WUS are transmitted to the terminal device 5 and the device 2 with which it is to communicate. By receiving the LP-SS and LP-WUS from the base station 4, the terminal device 5 and the device 2 in the deep sleep state can establish synchronization with the base station 4 and become operational (wireless communication, etc.).

[0100] In step S14, the base station 4 transmits a DL signal 32 (here, a data request signal) to the terminal device 5 and the device 2 with which it is communicating. The DL signal 32 is relayed between the multiple devices 2, and data d1 stored in a device 2 other than the device with which the higher-level device 3 is communicating is transmitted to the device 2 with which the higher-level device 3 is communicating by reverse relay transmission.

[0101] In step S15, each of the devices 2 transmits a UL relay signal 22 (data d1, relay count) or a UL signal 23 (data d1) in response to receiving the DL signal 32 or the relay signal 22 (data request, relay count). The UL signal 23 is transmitted from the device 2 with which the higher-level device 3 is to communicate to the higher-level device 3. The UL signal 23 may be transmitted via the terminal device 5 (via the terminal device 5) or may be transmitted without passing through the terminal device 5. The transmission of the relay signal 22 by each device 2 is performed based on the second time T2 of that device 2, as described above.

[0102] As mentioned above, the LP-SS and LP-WUS from the higher-level device 3 may be relayed among multiple devices 2. That is, in one embodiment, some of the multiple devices 2 may be located outside the communication area of ​​the higher-level device 3. Since the higher-level device 3 cannot directly transmit the LP-SS and LP-WUS to devices 2 outside their communication area, devices 2 that have established synchronization with the higher-level device 3 transmit the LP-SS and LP-WUS to devices 2 outside their communication area. This allows synchronization to be established among all devices 2 located in a wide area, including those outside the communication area of ​​the higher-level device 3. This will be described with reference to FIGS. 14 and 15.

[0103] 14 and 15 are sequence diagrams showing an example of a process (communication method) executed in the communication system 100. FIG.

[0104] The sequence of Figure 14 differs from that of Figure 12 described above, particularly in that it further includes the operation of step S3A. The LP-SS and LP-WUS transmitted by the base station 4 in step S3 are received by devices 2 within its communication area. The devices 2 (which may be a device group including two or more devices 2) that receive these signals establish synchronization with the base station 4. In step S3A, the devices 2 that have established synchronization transmit (relay) the LP-SS and LP-WUS to other devices 2 (which may be a device group including two or more devices 2) outside the communication area. All devices 2, including devices 2 located outside the communication area of ​​the higher-level device 3, can receive the LP-SS and LP-WUS.

[0105] The sequence in Fig. 15 differs from the previously described Fig. 13 in that it further includes the processing of step S13A. The operations of steps S13 and S13A are similar to the operations of steps S3 and S3A in Fig. 14, and therefore will not be described here.

[0106] According to the communication system 100 described above, the transmission time of the outgoing signal 21 from the device 2 to the device 1 can be controlled to be different for each region 9. Since the multiple devices 1 corresponding to the device 2 transmit the outgoing signal 12 in response to receiving the outgoing signal 21 from that device 2 (for example, immediately by backscattering), the transmission time of the outgoing signal 12 can also be controlled to be different for each region 9. Furthermore, the transmission time of the relay signal 22 from the device 2 to another device 2 can also be controlled to be different for each region 9. By performing such various controls (or at least some of the controls), it is possible to suppress multi-zone interference that may occur due to signal transmission.

[0107] Various other technical issues can also be addressed by the disclosed technology. For example, a method in which the base station 4 directly communicates with the device 1 can be considered. In this case, the base station 4 transmits a signal directly to the device 1, and each of the multiple devices 1 that receive the signal transmits a signal to the base station 4 using backscattering. However, in this case, due to the large coverage area, the signal transmitted from the device 1 to the base station 4 is significantly attenuated. A full duplex problem may occur in the base station 4, in which its own transmission signal interferes with the signal from the device 1. This problem is addressed by having the device 2 (rather than the base station 4) communicate with the multiple devices 1, as in the communication system 100 according to the embodiment.

[0108] Due to the low-power design of the device 1, the device 1 may not be able to adequately filter out signals from other cellular systems already in operation, possibly resulting in interference. This problem is particularly evident when the device 1 is installed outdoors. Such interference can be suppressed, for example, by making the DL and UL frequencies of the communication system 100 different from those of the other cellular systems. This can be addressed appropriately by the administrator of the cellular system, for example, the operator of the base station 4 of the communication system 100.

[0109] When the base station 4 communicates directly with the device 1, it is difficult for the base station 4 to directly and strictly control the timing of the transmission of the outgoing signal 12 from the device 1 using the backscattering method. This problem is addressed by controlling the timing of the outgoing signal 21 that the device 2 transmits to the device 1, as in the communication system 100 according to the embodiment.

[0110] When the base station 4 directly communicates with the device 1, the transmission frequency of the signal from the base station 4 to the device 1 must be a DL frequency, and the transmission frequency of the signal from the device 1 to the base station 4 must be an UL frequency. However, it may be technically difficult for the device 1, which has received a signal at a DL frequency, to transmit a signal at an UL frequency different from the DL frequency using backscattering. This problem is addressed by setting the transmission frequency of the signal 21 from the device 2 to the device 1 and the transmission frequency of the signal 12 from the device 1 to the device 2 to the same frequency (e.g., an UL frequency) as in the communication system 100 according to the embodiment.

[0111] As described above, the device 2 can independently generate, transmit, and receive signals by including an energy storage component for energy harvesting, a rectifier IC (Rectenna IC) for receiving wireless power transmitted by an external system, a large-capacity capacitor (supercapacitor), and the like. However, compared to a general device (e.g., the terminal device 5), the device 2's power consumption, functionality, and the like are significantly limited. For example, a crystal oscillator may not be usable. A simple oscillator has low clock accuracy, making it difficult to achieve clock-based synchronization. As described above, this problem can be addressed in the communication system 100 by using the low-power OOK modulation method, the specifications of which are currently being considered in the "LP-WUS" topic of 3GPP Release 18, as an example of a modulation method and synchronization establishment procedure. Initial synchronization can be established in the time domain and frequency domain using the LP-SS, which is periodically transmitted from the base station and is known to the device 2.

[0112] 16 is a diagram showing an example of a signal format. The illustrated frame configuration format can be applied to, for example, the DL signal 32 described above, more specifically, the provisioning signal, the data request signal (DL setting signal for UL operation), and the relay signal 22.

[0113] In this example, the signal includes preamble data, header data, and payload data. The preamble data located at the beginning is used for frame synchronization in the time domain and channel estimation (CE) of fluctuations due to fading. The header data is located after the preamble data. The header data is used to carry information for the physical layer (PHY layer) and the MAC layer (MAC layer) required to correctly demodulate the received payload data based on the packet size of the application layer.

[0114] In this example, the header data includes a physical header (PHY header), tail bits, a MAC header, a cyclic redundancy check (CRC), and tail bits. For example, the CRC is a CRC bit for detecting errors in the transmitted data. The tail bits are bits for error correction, and specifically, are trellis termination tail bits for convolutional coding and Viterbi decoding.

[0115] The payload data includes a frame payload, a CRC, and TailBits. The CRC of the payload data may be the same as the CRC of the header data described above.

[0116] In this example, when the signal is a relay signal 22, the data indicating the number of relays described above is incorporated into the physical header of the header data as a relay count bit (which can also be called a node passing bit). Note that the figure also shows a reserved bit, a payload indication bit, and a scrambler bit as other data included in the physical header.

[0117] It should be noted that the above signal formats are merely examples. Any signal format that enables the functions of the DL signal 32 and its relay signal 22 described above may be adopted. The same may be true for the UL signal 23 and the UL relay signal 22.

[0118] As mentioned above, the range of application of the communication system 100 can be freely changed by adjusting the number and arrangement of the devices 1 and 2. In particular, the wider the range of application, the greater the benefits. As one example of application, a greenhouse will be described.

[0119] Fig. 17 is a diagram showing an example of application to a greenhouse. The greenhouse covers a wide area, for example, several hundred meters. ２ , several thousand meters ２ , tens of thousands of meters ２ Or it may be one or more greenhouses (such as vinyl greenhouses) spread over a larger area, and in this example includes multiple greenhouses. The entire greenhouse is covered by multiple areas 9.

[0120] Although not shown in the figure, the devices 1 and 2 described above are installed in various locations in the greenhouse. For example, device 1 may have various sensor functions, and data indicating the sensing results may be device 1 data d1. Examples of data d1 include data on temperature, humidity, solar radiation, wind volume, and sound. Alternatively, device 1 may have an operation function for operating (controlling) a smart greenhouse, such as turning a mist sprinkler on and off or opening and closing greenhouse windows, and data indicating the operation content (which may include the operation results) may be device 1 data d1. Collecting and using the data d1 of each device 1 can be used to effectively control the greenhouse. Such a greenhouse may also be called a smart greenhouse.

[0121] For example, wired communication such as Ethernet (registered trademark) can be used to transmit data over a distance of tens of thousands of meters. ２ Controlling a greenhouse as large as 100 meters requires high initial costs and maintenance costs. By applying the communication system 100 described above (by using wireless communication), costs can be significantly reduced.

[0122] 4. Application Examples As explained above, by utilizing the device 2, which can be present in various places, it is possible to provide new technologies, services, etc. One application example is search technology.

[0123] 18 is a diagram showing an application example. In addition to the device 2 and higher-level device 3 (base station 4 and terminal device) described above, a terminal device 61 and a server device 62 are shown as components of the communication system 100. The terminal device 61 is, for example, a smartphone or other terminal device. The server device 62 communicates with the higher-level device 3 and the terminal device 61. In this example, communication is performed via a network 63.

[0124] A user of a terminal device 61 is illustrated and referred to as a user 6. The user 6 uses the terminal device 61 to find (search for) a target object 60. In the example shown in Fig. 18, the target object 60 is an earphone.

[0125] A device 2 is provided relative to the target 60. The device 2 is, for example, incorporated inside the target 60 or attached to the target 60. The position of the device 2 may indicate the position of the target 60. Data (e.g., a device ID, position data, etc.) that identifies the device 2 and the position of the device 2 may be transmitted from the device 2 to the higher-level device 3. The position data is acquired, for example, when the target 60 has remaining battery power, using a positioning function that utilizes a wireless communication method for local connectivity of a non-cellular system. In other words, when the target 60 itself has remaining battery power, the acquired position data is transmitted to the higher-level device 3 via the device 2 mounted in the same housing and collected.

[0126] A user 6 uses a terminal device 61 to send information (such as a device ID) about a device 2 provided for a target object 60 to a server device 62. This information is registered in the server device 62. The server device 62 holds (stores) the registered information. This information is referred to as a device list and is illustrated. The device list includes information about devices 2 provided for targets (including the target object 60) that multiple users (including the user 6) are trying to find.

[0127] The server device 62 refers to the device list and searches for a device 2 (search target device 2) that is provided for the target object 60 from among the multiple devices 2. For example, the server device 62 compares data collected by the higher-level device 3 with the device list. When the server device 62 finds a device 2 shown in the device list, it acquires location data, etc. of the device 2 and transmits the data to the terminal device 61 used by the user 6. The terminal device 61 presents (displays, etc.) information based on the location data, etc. to the user 6. In this way, the user 6 can find the target object 60.

[0128] In the above description, the target 60 is an earphone as an example, but the target 60 is not limited to an earphone. Various other items, such as a portable electronic device, can be the target 60. Generally, portable electronic devices can normally use existing wireless communication technologies, such as wireless LAN communication, Bluetooth (registered trademark) communication, and Ultra Wide Band (UWB) communication. However, when the battery power runs out, such wireless communication becomes impossible. Even in such a case, if the device 2 is provided for the target 60, the target 60 can be found.

[0129] Targets 60 other than electronic devices are also possible. For example, one example of the other targets 60 is a child, an elderly person, etc., and a monitoring service can be provided for them. Another example of the other targets 60 is a moving object such as a bicycle or a moped, and a service can be provided to prevent theft, abandonment, etc. of the moving object.

[0130] 5. Conclusion The techniques described above can be specified, for example, as follows. One of the techniques disclosed is a device 2. As described with reference to FIGS. 1 to 16 , the device 2 includes a wireless communication unit 201 and a control unit 202 that controls the wireless communication unit 201 so that, when the wireless communication unit 201 receives a DL signal 32 or its relay signal 22, the wireless communication unit 201 transmits an outgoing signal 21 to a plurality of devices 1 (first devices) after a first time T1 has elapsed. The first time T1 includes a waiting time Tw specific to the device 2.

[0131] According to the device 2 described above, when the device 2 and the corresponding devices 1 are provided and operated in each of a plurality of areas 9 (multi-zones), the transmission time of the transmission signal 21 from the device 2 to the device 1 can be controlled to be different for each area 9. This makes it possible to suppress multi-zone interference.

[0132] As described with reference to Figures 3, 4, 6, 7, 9 to 11, etc., the control unit 202 controls the wireless communication unit 201 so that, when the wireless communication unit 201 receives the DL signal 32 or its relay signal 22, the wireless communication unit 201 transmits the relay signal 22 to the other device 2 after the second time T2 has elapsed, and the second time T2 may include a waiting time Tw. This allows the transmission time of the relay signal 22 from the device 2 to the other device 2 to be controlled so as to differ for each region 9. This further increases the possibility of suppressing multi-zone interference.

[0133] 6 to 9, the waiting time Tw may be a time equal to or less than a predetermined time, the first time T1 may be the waiting time Tw, and the second time T2 may be the total time of the predetermined time and the waiting time Tw. For example, by transmitting the transmission signal 21 and the relay signal 22 based on such first time T1 and second time T2, it is possible to suppress multi-zone interference.

[0134] As described with reference to Figure 6 etc., the waiting time Tw is a time calculated based on information specific to the device 2, and the information specific to the device 2 may include a device ID. As described with reference to Figures 4, 6, 10 to 13 etc., the relay signal 22 includes a signal indicating the number of relays, and the information specific to the device 2 may include the number of relays. For example, based on such information specific to the device 2, it is possible to calculate the waiting time Tw specific to the device 2, and therefore the specific first time T1 and second time T2.

[0135] 10 and 12 , the DL signal 32 includes a provisioning signal, and the provisioning may include settings related to wireless communication. For example, by transmitting a relay signal 22 of such a DL signal 32, it is possible to control each of the multiple devices 2 to perform provisioning.

[0136] 3 , 4 , 10 , 12 , etc., the control unit 202 may control the wireless communication unit 201 to receive an outgoing signal 12 from each of the multiple devices 1 in response to an outgoing signal 21 from the wireless communication unit 201 to each of the multiple devices 1. The device 2 may include a storage unit 203 that stores data d1 of each of the multiple devices 1 obtained from the outgoing signal 12 from each of the multiple devices 1. This allows the data d1 of each of the multiple devices 1 to be stored (held) in the device 2.

[0137] 5 and other figures, the transmission frequency of the outgoing signal 21 from the wireless communication unit 201 to the device 1 is the UL frequency in the wireless communication between the device 2 and the higher-level device 3, and the transmission frequency of the outgoing signal 12 from the device 1 to the wireless communication unit 201 may also be the UL frequency. This increases the likelihood that the device 1 will be able to transmit the outgoing signal 12 more easily than when the transmission frequencies of the outgoing signal 21 and the outgoing signal 12 are different from each other (for example, when one is a DL frequency and the other is a UL frequency). This is effective, for example, when the device 1 transmits the outgoing signal 12 using a backscattering method.

[0138] 11 and 13 , the DL signal 32 includes a data request signal, and when the wireless communication unit 201 receives the DL signal 32 including the data request signal or its relay signal 22, the control unit 202 may transmit the UL relay signal 22 including the requested data (corresponding to the data d1 of the device 1) to another device 2, or may transmit the UL signal 23 including the requested data to the higher-level device 3. This allows the data d1 of each of the multiple devices 1 to be transmitted to the higher-level device 3 and collected.

[0139] 1, 3, 12 to 15, etc., the control unit 202 may control the wireless communication unit 201 so that the wireless communication unit 201 receives the LP-SS and LP-WUS from the higher-level device 3, transitions from the deep sleep state to the awake state, establishes synchronization with the higher-level device 3, and then receives the DL signal 32. For example, by establishing synchronization with the higher-level device 3 in this manner, it is possible to receive the DL signal 32 from the higher-level device 3. Furthermore, since the device 2 is capable of entering the deep sleep state, it is possible to provide a device 2 with reduced power consumption.

[0140] 1, 3, 14, 15, etc., after the establishment of the above-described synchronization, the control unit 202 may control the wireless communication unit 201 so that the wireless communication unit 201 transmits the LP-SS and LP-WUS to other devices 2 located outside the communication area with the higher-level device 3. This makes it possible to establish synchronization among all of the devices 2 located in a wide range of areas, including outside the communication area of ​​the higher-level device 3.

[0141] As described with reference to Figures 1 and 3, the modulation method of LP-SS may include OOK modulation, the higher-level device 3 may include a base station 4, and the device 2 may establish synchronization with the base station 4 based on LP-SS. This makes it possible to ensure synchronization with low power consumption even when using an oscillator with lower accuracy than a crystal oscillator, for example. The modulation method of the outgoing signal 21 and relay signal 22 transmitted by the wireless communication unit 201 may also include OOK modulation.

[0142] The communication method described with reference to Figures 1 to 16 is also one of the disclosed techniques. The communication method includes, when a device 2 receives a DL signal 32 or its relay signal 22, transmitting an outgoing signal 21 to a plurality of devices 1 (first devices) after a first time T1 has elapsed (steps S5 and S15). The first time T1 includes a waiting time Tw specific to the device 2. As described above, such a communication method can also suppress multi-zone interference.

[0143] The communication system 100 described with reference to Figures 1 to 16 is also one of the disclosed technologies. The communication system 100 includes a plurality of devices 1 (first devices), a plurality of devices 2 (second devices), each of which communicates with a corresponding plurality of devices 1 among the plurality of devices 1, and a higher-level device 3 (e.g., at least one of a base station 4 and a terminal device 5) that communicates with some of the plurality of devices 2. When a device 2 receives a DL signal 32 from the higher-level device 3 or a relay signal 22 of the DL signal 32 from another device 2, the device 2 transmits an outgoing signal 21 to the corresponding plurality of devices 1 after a first time T1 has elapsed. The first time T1 includes a waiting time Tw specific to the device 2. As described above, such a communication system 100 can also suppress multi-zone interference.

[0144] 1 and 2 , upon receiving an outgoing signal 21 from device 2, device 1 may transmit an outgoing signal 12 to device 2 by backscattering. The power consumption of device 1 may be smaller than the power consumption of device 2. For example, a communication system 100 with reduced power consumption can be constructed using such a device 1.

[0145] 17 and the like, multiple devices 1 are installed in a greenhouse, and the signal 12 transmitted from device 1 to device 2 may include at least one of sensing data acquired in the greenhouse and data indicating the operation of the greenhouse (corresponding to data d1). For example, the communication system 100 can be applied to such a smart greenhouse.

[0146] 18 and the like, the communication system 100 may include a server device 62 that searches for a device 2 provided for a target 60 from among a plurality of devices 2. This makes it possible to provide a search service using the communication system 100.

[0147] The effects described in this disclosure are merely examples and are not limited to the disclosed contents. Other effects may also be obtained.

[0148] 6. Configuration Examples of Base Station and Terminal Device <Configuration Example of Base Station 4> As described above, the base station 4 is a wireless communication device that performs wireless communication with other wireless communication devices (e.g., the device 2, the terminal device 5, and other base stations 4). The base station 4 may communicate wirelessly with other wireless communication devices via a relay station, or may communicate wirelessly directly with the other wireless communication devices.

[0149] The base station 4 is a device equivalent to a wireless base station (such as a base station, node B, eNB, gNB, or 6GNB) or a wireless access point. The base station 4 may be a wireless relay station. The base station 4 may be an optical device called a remote radio head (RRH). The base station 4 may be a receiving station such as a field pickup unit (FPU). The base station 4 may be an integrated access and backhaul (IAB) donor node or an IAB relay node that provides wireless access lines and wireless backhaul lines using time division multiplexing, frequency division multiplexing, or space division multiplexing.

[0150] The wireless access technology used by the base station 4 may be cellular communication technology. The wireless access technology used by the base station 4 may be wireless LAN technology. The wireless access technology used by the base station 4 may be low-power wide-area (LPWA) communication technology. However, the wireless access technology used by the base station 4 is not limited to these and may be other wireless access technologies. The wireless communication used by the base station 4 may be wireless communication using millimeter waves or wireless communication using terahertz waves. The wireless communication used by the base station 4 may be wireless communication using radio waves or wireless communication using infrared or visible light (optical wireless). Furthermore, the base station 4 may be capable of NOMA (Non-Orthogonal Multiple Access) communication with the terminal device 5. Here, NOMA communication refers to communication (transmission, reception, or both) using non-orthogonal resources. Note that the base station 4 may be capable of NOMA communication with other base stations 4.

[0151] The base station 4 may be capable of communicating with the core network via a base station-core network interface (e.g., NG Interface, S1 Interface, etc.). This interface may be either wired or wireless. The base station may also be capable of communicating with other base stations via an inter-base station interface (e.g., Xn Interface, X2 Interface, F1 Interface, etc.). This interface may be either wired or wireless.

[0152] The concept of a base station (also referred to as a "base station device") includes not only a donor base station but also a relay base station (also referred to as a "relay station"). A relay base station may be any one of an RF Repeater, a Smart Repeater, and an Intelligent Surface. The concept of a base station may also include a road-side unit (RSU). The concept of a base station may also include not only a structure having the functions of a base station but also a device installed in the structure.

[0153] Examples of structures include high-rise buildings, houses, steel towers, station facilities, airport facilities, port facilities, office buildings, school buildings, hospitals, factories, commercial facilities, stadiums, and other buildings. The concept of a structure includes not only buildings, but also non-building structures such as tunnels, bridges, dams, fences, and steel pillars, as well as equipment such as cranes, gates, and wind turbines. The concept of a structure includes not only land (ground in the narrow sense) or underground structures, but also water-based structures such as piers or megafloats, and underwater structures such as ocean observation facilities. A base station can also be referred to as an information processing device.

[0154] The base station 4 may be a donor station or a relay station (relay station). The base station 4 may also be a fixed station or a mobile station. A mobile station is a wireless communication device (e.g., a base station) configured to be mobile. In this case, the base station 4 may be a device installed in a mobile body, or may be the mobile body itself. For example, a relay station with mobility can be considered a base station 4 as a mobile station. Furthermore, devices that are inherently mobile and have base station functionality (at least part of the base station functionality), such as vehicles, unmanned aerial vehicles (UAVs) such as drones, and smartphones, also fall under the category of a base station 4 as a mobile station.

[0155] Here, the mobile body may be a mobile terminal such as a smartphone or a mobile phone. The mobile body may be a mobile body that moves on land (ground in the narrow sense) (e.g., a vehicle such as an automobile, bicycle, bus, truck, motorcycle, train, or linear motor car), or a mobile body that moves underground (e.g., in a tunnel) (e.g., a subway). The mobile body may also be a mobile body that moves on water (e.g., a ship such as a passenger ship, cargo ship, or hovercraft), or a mobile body that moves underwater (e.g., a submersible vessel such as a submarine, submarine, or unmanned underwater vehicle). The mobile body may also be a mobile body that moves within the atmosphere (e.g., an aircraft such as an airplane, airship, or drone).

[0156] The base station 4 may be a terrestrial base station (ground station) installed on the ground. The base station 4 may be a base station located on a structure on the ground, or a base station installed on a mobile object moving on the ground. The base station 4 may be an antenna installed on a structure such as a building and a signal processing device connected to the antenna. The base station 4 may be the structure or the mobile object itself. "Terrestrial" refers not only to land (terrestrial in the narrow sense) but also to ground, on water, and underwater. The base station 4 is not limited to a terrestrial base station. In the case of a satellite communication system, the base station 4 may be an aircraft station. From the perspective of the satellite station, an aircraft station located on Earth is a ground station.

[0157] The base station 4 is not limited to a terrestrial station. The base station 4 may be a non-terrestrial base station (non-terrestrial station) that can float in the air or space. The base station 4 may be an aircraft station or a satellite station.

[0158] A satellite station is a satellite station capable of floating outside the atmosphere. The satellite station may be a device mounted on a space vehicle such as an artificial satellite, or may be the space vehicle itself. A space vehicle is a vehicle that moves outside the atmosphere. The space vehicle may be at least one of an artificial satellite, a spacecraft, a space station, and a probe. Of course, the space vehicle may also be an artificial celestial body other than these. Note that a satellite that serves as a satellite station may be any of a low Earth orbiting (LEO) satellite, a medium Earth orbiting (MEO) satellite, a geostationary Earth orbiting (GEO) satellite, or a highly elliptical orbiting (HEO) satellite. The satellite station may be a device mounted on a low Earth orbiting satellite, a medium Earth orbiting satellite, a geostationary satellite, or a highly elliptical orbiting satellite.

[0159] An aircraft station is a wireless communication device capable of floating in the atmosphere of an aircraft or the like. The aircraft station may be a device mounted on the aircraft or the like, or may be the aircraft itself. The concept of aircraft includes not only heavier-than-air vehicles such as airplanes and gliders, but also lighter-than-air vehicles such as balloons and airships. The concept of aircraft includes not only heavier-than-air vehicles or lighter-than-air vehicles, but also rotorcraft such as helicopters and autogyros. The aircraft station, or an aircraft equipped with an aircraft station, may be an unmanned aerial vehicle such as a drone.

[0160] The concept of unmanned aerial vehicles also includes unmanned aerial systems (UAS) and tethered unmanned aerial systems (UAS). The concept of unmanned aerial vehicles also includes lighter than air UAS (LTA) and heavier than air UAS (HTA). The concept of unmanned aerial vehicles also includes high altitude unmanned aerial system platforms (HAPs).

[0161] The coverage size of the base station 4 may be relatively large, such as a macrocell, or relatively small, such as a picocell. The coverage size of the base station 4 may be extremely small, such as a femtocell. The base station 4 may have a beamforming function. The base station 4 may form a cell or service area for each beam. Additionally or alternatively, in addition to beamforming, which gives directionality to the beam, the base station 4 may have a function to pinpoint a desired wave to a specific point by further considering distance information from the antenna of the base station 4. This function may be called beam focusing or point forming. The base station 4 may also be configured to acquire detection data by performing sensing using the beam.

[0162] Fig. 19 is a block diagram showing an example of a schematic configuration of the base station 4. The base station 4 includes a wireless communication unit 41, a storage unit 42, and a control unit 43. However, the configuration shown in Fig. 19 is a functional configuration, and the hardware configuration may be different. Furthermore, the functions of the base station 4 may be distributed and implemented in multiple physically separated units.

[0163] The wireless communication unit 41 is a signal processing unit for wireless communication with other wireless communication devices (e.g., at least one of the device 2, the terminal device 5, and another base station 4). The wireless communication unit 41 may be referred to as a wireless transceiver or simply as a transceiver. In this case, the wireless communication unit 41 may be a transceiver (hereinafter referred to as a 3GPP transceiver) conforming to the specifications defined in the Technical Specification (TS) of the 3rd Generation Partnership Project (3GPP). The 3GPP transceiver may be a 3G transceiver, a 4G (LTE) transceiver, a 5G (NR) transceiver, or a transceiver of a generation after 5G. The wireless communication unit 41 is controlled by the control unit 43. The wireless communication unit 41 supports one or more wireless access methods. The wireless communication unit 41 may support at least one of NR, LTE, B5G (Beyond 5G), and 6G. The wireless communication unit 41 may support W-CDMA, cdma2000, etc. in addition to NR, LTE, B5G, and 6G. The wireless communication unit 41 may support automatic retransmission techniques such as HARQ (Hybrid Automatic Repeat reQuest). A part or all of the processing performed by the wireless communication unit 41 may be performed by the control unit 43.

[0164] The wireless communication unit 41 includes a transmission processing unit 411, a reception processing unit 412, and an antenna 413. Alternatively, at least one of the transmission processing unit 411, the reception processing unit 412, and the antenna 413 may be considered as the wireless communication unit 41. The wireless communication unit 41 may include a plurality of transmission processing units 411, a plurality of reception processing units 412, and a plurality of antennas 413. When the wireless communication unit 41 supports a plurality of wireless access methods, each unit of the wireless communication unit 41 may be configured individually for each wireless access method. The transmission processing unit 411 and the reception processing unit 412 may be configured individually for LTE, NR, B5G, and 6G. The antenna 413 may be configured with a plurality of antenna elements, for example, a plurality of patch antennas. The wireless communication unit 41 may have a beamforming function. For example, the wireless communication unit 41 may have a polarization beamforming function using vertical polarization (V polarization) and horizontal polarization (H polarization) (or a polarization beamforming function using dual polarization in polarization directions of 45 degrees and -45 degrees from the vertical direction).

[0165] The transmission processing unit 411 performs transmission processing of the downlink control information and downlink data. For example, the transmission processing unit 411 encodes the downlink control information and downlink data input from the control unit 43 using a coding method such as block coding, convolutional coding, or turbo coding. Here, the encoding may be performed using polar codes or low density parity check codes (LDPC codes). The transmission processing unit 411 then modulates the coded bits using a predetermined modulation method (e.g., BPSK, QPSK, 16QAM, 64QAM, 256QAM, or a higher-order multi-level modulation method). In this case, the signal points on the constellation do not necessarily need to be equidistant. The constellation may also be a non-uniform constellation (NUC). The transmission processing unit 411 then multiplexes the modulation symbols of each channel and the downlink reference signal and allocates them to predetermined resource elements. The transmission processing unit 411 then performs various signal processing on the multiplexed signal. For example, the transmission processing unit 411 performs processes such as conversion to the frequency domain by fast Fourier transform, addition of a guard interval (cyclic prefix), generation of a baseband digital signal, conversion to an analog signal, quadrature modulation, up-conversion, removal of unnecessary frequency components, power amplification, etc. The signal generated by the transmission processing unit 411 is transmitted from an antenna 413.

[0166] The reception processing unit 412 processes the uplink signal received via the antenna 413. For example, the reception processing unit 412 performs downconversion, removal of unnecessary frequency components, control of amplification level, quadrature demodulation, conversion to a digital signal, removal of guard intervals (cyclic prefixes), extraction of frequency domain signals by fast Fourier transform, and the like on the uplink signal. The reception processing unit 412 then separates uplink channels such as PUSCH (Physical Uplink Shared Channel) and PUCCH (Physical Uplink Control Channel) and uplink reference signals from the processed signal. The reception processing unit 412 also demodulates the received signal using a modulation method such as BPSK (Binary Phase Shift Keying) or QPSK (Quadrature Phase Shift Keying) for the modulation symbols of the uplink channel. The modulation method used for demodulation may be 16QAM (Quadrature Amplitude Modulation), 64QAM, or 256QAM. In this case, the signal points on the constellation do not necessarily have to be equidistant. The constellation may be a non-uniform constellation (NUC). The reception processing unit 412 then performs decoding processing on the coded bits of the demodulated uplink channel. The decoded uplink data and uplink control information are output to the control unit 43.

[0167] The antenna 413 is an antenna device that converts electric current and radio waves into each other. The antenna 413 may be composed of a single antenna element, for example, a single patch antenna. The antenna 413 may be composed of multiple antenna elements, for example, multiple patch antennas. When the antenna 413 is composed of multiple antenna elements, the wireless communication unit 41 may have a beamforming function. The wireless communication unit 41 may be configured to generate a directional beam by controlling the directivity of a wireless signal using the multiple antenna elements. The antenna 413 may be a dual-polarized antenna. When the antenna 413 is a dual-polarized antenna, the wireless communication unit 41 may use vertical polarization (V polarization) and horizontal polarization (H polarization) (or dual polarization with polarization directions at 45 degrees and -45 degrees from the vertical direction) when transmitting a wireless signal. The wireless communication unit 41 may control the directivity of a wireless signal transmitted using vertical polarization and horizontal polarization (or dual polarization with polarization directions at 45 degrees and -45 degrees from the vertical direction). Furthermore, the wireless communication unit 41 may transmit and receive spatially multiplexed signals via multiple layers each made up of multiple antenna elements.

[0168] The storage unit 42 is a readable and writable storage device such as a DRAM, an SRAM, a flash memory, or a hard disk.

[0169] The control unit 43 is a controller that controls each unit of the base station 4. The control unit 43 controls the wireless communication unit to perform wireless communication with other wireless communication devices (e.g., the device 2, the terminal device 5, or another base station 4). The control unit 43 may be implemented by a processor such as a CPU or an MPU. Specifically, the control unit 43 may be implemented by a processor executing various programs stored in a storage device inside the base station 4 using RAM or the like as a work area. The control unit 43 may be implemented by an integrated circuit such as an ASIC or an FPGA. The control unit 43 may also be implemented by a GPU. A CPU, an MPU, an ASIC, an FPGA, and a GPU can all be considered controllers. The control unit 43 may be composed of multiple physically separated objects. For example, the control unit 43 may be composed of multiple semiconductor chips.

[0170] The functional block of the control unit 43 may be a software block or a hardware block. For example, the functional block may be a software module implemented by software (including a microprogram) or a circuit block on a semiconductor chip (die). The functional block may be a processor or an integrated circuit. The operation of the control unit 43 may be the same as the operation of the control unit 53 of the terminal device 5 in FIG. 20 described below.

[0171] In some embodiments, the base station 4 may be configured as a collection of multiple physical or logical devices. As an example, the base station 4 of this embodiment may be divided into multiple devices such as a baseband unit (BBU) and a radio unit (RU). The base station 4 may be interpreted as a collection of these multiple devices. Furthermore, the base station may be either a BBU or an RU, or both. The BBU and the RU may be connected by a predetermined interface such as an enhanced Common Public Radio Interface (eCPRI).

[0172] The RU may be referred to as an RRU (Remote Radio Unit) or an RD (Radio DoT). The RU may correspond to a gNB-DU (gNB Distributed Unit) described later. The BBU may correspond to a gNB-CU (gNB Central Unit) described later. The RU may be a device integrally formed with an antenna. The antenna of the base station 4, for example, an antenna integrally formed with the RU, may employ an Advanced Antenna System and support, for example, MIMO such as FD-MIMO or beamforming. The antenna of the base station 4 may include, for example, 64 transmitting antenna ports and 64 receiving antenna ports.

[0173] The antenna mounted on the RU may be an antenna panel consisting of one or more antenna elements, and the RU may be equipped with one or more antenna panels. The RU may be equipped with two types of antenna panels, a horizontally polarized antenna panel and a vertically polarized antenna panel. The RU may be equipped with two types of antenna panels, a right-hand circularly polarized antenna panel and a left-hand circularly polarized antenna panel, or an antenna panel with a polarization direction at 45 degrees from the vertical direction and an antenna panel with a polarization direction at -45 degrees from the vertical direction. Multiple antennas with these multiple polarization directions may be mounted on a single antenna panel. The RU may form and control an independent beam for each antenna panel.

[0174] A plurality of base stations 4 may be connected to each other. One or more base stations 4 may be included in a radio access network (RAN). In this case, the base station 4 may be simply referred to as a RAN, a RAN node, an AN (Access Network), an AN node, or the like. The RAN in LTE may be called an Enhanced Universal Terrestrial RAN (EUTRAN). The RAN in NR may be called an NGRAN. Furthermore, the RAN in 6G may be called a 6GRAN. The RAN in W-CDMA (UMTS) may be called a UTRAN.

[0175] An LTE base station 4 may be referred to as an eNodeB (Evolved Node B) or eNB. In this case, the EUTRAN includes one or more eNodeBs (eNBs). An NR base station 4 may be referred to as a gNodeB or gNB. In this case, the NGRAN includes one or more gNBs. A 6G base station may be referred to as a 6GNodeB, 6gNodeB, 6GNB, or 6gNB. In this case, the 6GRAN includes one or more 6GNBs. The EUTRAN may include a gNB (en-gNB) connected to a core network (EPC) in an LTE communication system (EPS). The NGRAN may include an ng-eNB connected to a core network 5GC in a 5G communication system (5GS).

[0176] When the base station 4 is an eNB, gNB, 6GNB, or the like, the base station 4 may be referred to as a 3GPP access. When the base station 4 is a wireless access point, the base station 4 may be referred to as a non-3GPP access. The base station 4 may be an optical extension device called an RRH (Remote Radio Head). When the base station 4 is a gNB, the base station 4 may be a combination of the gNB-CU and gNB-DU described above, or may be either a gNB-CU or a gNB-DU.

[0177] Here, the gNB-CU hosts multiple upper layers (e.g., RRC (Radio Resource Control), SDAP (Service Data Adaptation Protocol), PDCP (Packet Data Convergence Protocol)) of the access stratum for communication with the UE. On the other hand, the gNB-DU hosts multiple lower layers (e.g., RLC (Radio Link Control), MAC (Medium Access Control), PHY (Physical layer)) of the access stratum. That is, among the messages / information described below, RRC signaling (semi-static notification) is generated by the gNB-CU, while MAC The CE and DCI (dynamic notification) may be generated by the gNB-DU. Alternatively, some configurations of the RRC configuration (semi-static notification), such as IE:cellGroupConfig, may be generated by the gNB-DU, and the remaining configurations may be generated by the gNB-CU. These configurations may be transmitted and received over the F1 interface described below.

[0178] The base station 4 may be configured to be able to communicate with other base stations. When multiple base stations 4 are eNBs or a combination of eNBs and en-gNBs, these base stations 30 may be connected to each other via an X2 interface. When multiple base stations 4 are gNBs or a combination of gn-eNBs and gNBs, these base stations 4 may be connected to each other via an Xn interface. When multiple base stations 4 are a combination of gNB-CUs and gNB-DUs, these base stations 4 may be connected to each other via the F1 interface described above. Messages / information (e.g., RRC signaling, MAC Control Element (CE), or Downlink Control Information (DCI)) described below may be transmitted between multiple base stations 4 via these inter-base station interfaces (e.g., X2 interface, Xn interface, or F1 interface).

[0179] A cell provided by a base station 4 may be referred to as a serving cell. The concept of a serving cell includes a PCell (Primary Cell) and an SCell (Secondary Cell). When dual connectivity is provided to a terminal device 5, a PCell and zero or more SCells provided by a Master Node (MN) may be referred to as a Master Cell Group. The dual connectivity may be at least one of EUTRA-EUTRA Dual Connectivity, EUTRA-NR Dual Connectivity (ENDC), EUTRA-NR Dual Connectivity with 5GC, NR-EUTRA Dual Connectivity (NEDC), NR-NR Dual Connectivity, NR-6G Dual Connectivity, and 6G-NR Dual Connectivity. Of course, dual connectivity is not limited to these.

[0180] The serving cell may include a PSCell (Primary Secondary Cell or Primary SCG Cell). When dual connectivity is provided to the terminal device 5, the PSCell provided by a Secondary Node (SN) and zero or more SCells may be referred to as a Secondary Cell Group (SCG). Unless special configuration (e.g., PUCCH on SCell) is performed, the Physical Uplink Control Channel (PUCCH) is transmitted by the PCell and PSCell but not by the SCell. Radio link failure is detected by the PCell and PSCell but not (does not need to be detected by) the SCell. As such, the PCell and PSCell play special roles among the serving cells and are therefore also referred to as Special Cells (SpCells).

[0181] One cell may be associated with one downlink component carrier and one uplink component carrier. The system bandwidth corresponding to one cell may be divided into multiple BWPs (Bandwidth Parts). In this case, one or multiple BWPs may be configured in the terminal device 5, and one BWP may be used by the terminal device 5 as an active BWP. Radio resources that the terminal device 5 can use, such as a frequency band, numerology (subcarrier spacing), or slot format (Slot configuration), may differ for each cell, each component carrier, or each BWP.

[0182] <Configuration Example of Terminal Device 5> The terminal device 5 is a wireless communication device that performs wireless communication with other wireless communication devices (e.g., the device 2, the base station 4, other terminal devices 5). The terminal device 5 can be referred to as UE (User Equipment).

[0183] The terminal device 5 may be any type of information processing device (computer). For example, the terminal device 5 may be a mobile terminal such as a mobile phone, a smart device (smartphone or tablet), a PDA (Personal Digital Assistant), or a notebook PC. The terminal device 5 may also be a communication module that is connected to an information processing device (for example, an imaging device without wireless communication functionality) and provides the information processing device with wireless communication functionality. The terminal device 5 may also be an imaging device with wireless communication functionality (for example, a camcorder).

[0184] The terminal device 5 may also be a motorcycle or a mobile broadcasting vehicle equipped with a communication device such as a Field Pickup Unit (FPU). The terminal device 5 may also be a Machine to Machine (M2M) device or an Internet of Things (IoT) device. The terminal device 5 may also be a wearable device such as a smartwatch.

[0185] Furthermore, the terminal device 5 may be an XR (Extended Reality) device such as an AR (Augmented Reality) device, a VR (Virtual Reality) device, or an MR (Mixed Reality) device. In this case, the XR device may be a glasses-type device such as AR glasses or MR glasses, or a head-mounted device such as a VR head-mounted display. When the terminal device 5 is an XR device, the terminal device 5 may be a standalone device consisting only of a part worn by a user (e.g., a glasses part). Furthermore, the terminal device 5 may be a terminal-linked device consisting of a part worn by a user (e.g., a glasses part) and a terminal part (e.g., a smart device) linked to the part worn by a user.

[0186] The terminal device 5 may be capable of NOMA communication with the base station 4. The terminal device 5 may be able to use an automatic repeat technique such as HARQ when communicating with the base station 4. The terminal device 5 may be capable of sidelink communication with another terminal device 5. The terminal device 5 may be able to use an automatic repeat technique such as HARQ when performing sidelink communication. The terminal device 5 may be capable of NOMA communication when performing sidelink communication with another terminal device 5. The terminal device 5 may be capable of LPWA communication with other wireless communication devices such as the base station 4. The wireless communication used by the terminal device 5 may be wireless communication using millimeter waves. The wireless communication used by the terminal device 5, including sidelink communication, may be wireless communication using radio waves, or wireless communication using infrared or visible light, i.e., optical wireless.

[0187] The terminal device 5 may be a mobile wireless communication device, i.e., a mobile device. The terminal device 5 may be a wireless communication device installed in a mobile device, or may be the mobile device itself. The terminal device 5 may be a vehicle that moves on a road, such as an automobile, bus, truck, or motorcycle, or a train that runs on a track, or may be a wireless communication device mounted on the vehicle. The mobile device may be a mobile terminal, or a mobile device that moves on land (ground in the narrow sense), underground, on water, or underwater. The mobile device may also be a mobile device that moves within the atmosphere, such as an airplane, airship, balloon, or helicopter, or a mobile device that moves outside the atmosphere, such as an artificial satellite. The mobile device may also be a UAV (Unmanned Aerial Vehicle) such as a drone. The terminal device 5 may also be a wireless communication device mounted on the mobile device.

[0188] The terminal device 5 may be capable of simultaneously connecting to and communicating with a plurality of base stations 4 or a plurality of cells. When one base station 4 supports a communication area via a plurality of cells (for example, pCell or sCell), the plurality of cells can be bundled together to enable communication between the base station 4 and the terminal device 5 by using carrier aggregation (CA) technology, dual connectivity (DC) technology, multi-connectivity (MC) technology, or the like. Alternatively, communication between the terminal device 5 and the plurality of base stations 4 can also be enabled by using coordinated multi-point transmission and reception (CoMP) technology via cells of different base stations 4.

[0189] The terminal device 5 may be a relay terminal that relays communication to a remote terminal.

[0190] Fig. 20 is a block diagram showing an example of a schematic configuration of the terminal device 5. The terminal device 5 includes a wireless communication unit 51, a storage unit 52, a control unit 53, an input unit 54, and an output unit 55. The configuration shown in Fig. 20 is a functional configuration, and the hardware configuration may be different from this. Furthermore, the functions of the terminal device 5 may be distributed and implemented in multiple physically separated components.

[0191] The terminal device 5 may have a beamforming function.

[0192] The wireless communication unit 51 is a signal processing unit for wireless communication with other wireless communication devices (e.g., the device 2, the base station 4, and other terminal devices 5). The wireless communication unit 51 may be referred to as a wireless transceiver or simply as a transceiver. In this case, the wireless communication unit 51 may be a transceiver of a standard defined by the 3GPP Technical Specification (TS) (hereinafter referred to as a 3GPP transceiver). The 3GPP transceiver may be a 3G transceiver, a 4G (LTE) transceiver, a 5G (NR) transceiver, or a transceiver of a generation after 5G. The wireless communication unit 51 is controlled by, for example, the control unit 53. The wireless communication unit 51 supports one or more wireless access methods. The wireless communication unit 51 may support at least one of NR, LTE, B5G (Beyond 5G), and 6G. The wireless communication unit 51 may support W-CDMA, cdma2000, etc. in addition to NR, LTE, B5G, and 6G. The wireless communication unit 51 may support automatic retransmission techniques such as HARQ (Hybrid Automatic Repeat reQuest). Some or all of the processing performed by the wireless communication unit 51 may be performed by the control unit 43.

[0193] The wireless communication unit 51 includes a transmission processing unit 511, a reception processing unit 512, and an antenna 513. At least one of the transmission processing unit 511, the reception processing unit 512, and the antenna 513 may be considered as the wireless communication unit 51. The wireless communication unit 51 may include a plurality of transmission processing units 511, a plurality of reception processing units 512, and a plurality of antennas 513. When the wireless communication unit 51 supports a plurality of wireless access methods, each unit of the wireless communication unit 51 may be configured individually for each wireless access method. The transmission processing unit 511 and the reception processing unit 512 may be configured individually for LTE, NR, B5G, and 6G. The antenna 513 may be configured with a plurality of antenna elements, for example, a plurality of patch antennas. The wireless communication unit 51 may have a beamforming function. For example, the wireless communication unit 51 may have a polarization beamforming function using vertical polarization (V polarization) and horizontal polarization (H polarization) (or a polarization beamforming function using dual polarization in polarization directions of 45 degrees and -45 degrees from the vertical direction).

[0194] The storage unit 52 is a readable and writable storage device such as a DRAM, an SRAM, a flash memory, or a hard disk.

[0195] The control unit 53 is a controller that controls each unit of the terminal device 5. The control unit 53 controls the wireless communication unit to perform wireless communication with other wireless communication devices (e.g., the device 2, the base station 4, other terminal devices 5). The control unit 53 may be implemented by a processor such as a CPU or an MPU. In particular, the control unit 53 may be implemented by a processor executing various programs stored in an internal storage device of the terminal device 5 using RAM or the like as a work area. The control unit 53 may be implemented by an integrated circuit such as an ASIC or an FPGA. The CPU, MPU, ASIC, and FPGA can all be considered controllers. The control unit 53 may be implemented by a GPU. The CPU, MPU, ASIC, FPGA, and GPU can all be considered controllers. The control unit 53 may be composed of multiple physically separated objects. For example, the control unit 53 may be composed of multiple semiconductor chips.

[0196] The functional block of the control unit 53 may be a software block or a hardware block. For example, the functional block may be a software module implemented by software (including a microprogram), or may be a circuit block on a semiconductor chip (die). Of course, the functional block may be a processor or an integrated circuit. The functional block may be configured in any manner. The operation of the control unit 53 may be the same as the operation of the control unit 43 of the base station 4 in FIG. 19 described above.

[0197] The input unit 54 is an input device that accepts various inputs from the outside. For example, the input unit 54 is an operation device such as a keyboard, a mouse, operation keys, or voice input, which allows the user to perform various operations. Note that if a touch panel is employed in the terminal device 5, the touch panel is also included in the input unit 54. In this case, the user performs various operations by touching the screen with a finger or a stylus.

[0198] The output unit 55 is a device that outputs various types of information to the outside, such as sound, light, vibration, and image. The output unit 55 includes a display unit that displays various types of information. The display unit is, for example, a display device such as a liquid crystal display or an organic EL (Electro Luminescence) display. If a touch panel is employed in the terminal device 5, the display unit may be integrated with the input unit 54. If the terminal device 5 is an XR device, the terminal device 5 may be a transparent device that projects an image onto glasses, or a retinal projection device that projects an image directly onto the user's retina. The output unit 55 outputs various types of information to the user under the control of the control unit 53.

[0199] For example, the base station 4 and the terminal device 5 having the configurations described above may be used as the previously described higher-level device 3. In this case, appropriate technical design may be added to the base station 4 and the terminal device 5 so that they can perform operations such as communication with the device 2 described above.

[0200] Although the embodiments of the present disclosure have been described above, the technical scope of the present disclosure is not limited to the above-described embodiments, and various modifications are possible within the scope of the gist of the present disclosure. Furthermore, components of different embodiments and modifications may be combined as appropriate.

[0201] The present technology may also be configured as follows. (1) A device including: a wireless communication unit; and a control unit that controls the wireless communication unit to transmit an outgoing signal to a plurality of first devices after a first time has elapsed when the wireless communication unit receives a downlink (DL) signal or a relay signal thereof, wherein the first time includes a waiting time specific to the device. (2) The device described in (1), wherein the control unit controls the wireless communication unit to transmit a relay signal to other devices after a second time has elapsed when the wireless communication unit receives the DL signal or a relay signal thereof, and the second time includes the waiting time. (3) The device described in (2), wherein the waiting time is a time equal to or less than a predetermined time, the first time is the waiting time, and the second time is a total of the predetermined time and the waiting time. (4) The device described in any of (1) to (3), wherein the waiting time is a time calculated based on information specific to the device, and the information specific to the device includes a device ID. (5) The device according to any one of (1) to (4), wherein the waiting time is a time calculated based on information specific to the device, the relay signal includes a signal indicating the number of relays, and the information specific to the device includes the number of relays. (6) The device according to any one of (1) to (5), wherein the DL signal includes a provisioning signal, and the provisioning includes settings related to wireless communication. (7) The device according to any one of (1) to (6), wherein the control unit controls the wireless communication unit to receive an outgoing signal from each of the plurality of first devices that is a response to an outgoing signal from the wireless communication unit to each of the plurality of first devices. (8) The device according to (7), wherein the device includes a storage unit that stores data of each of the plurality of first devices obtained from the outgoing signal from each of the plurality of first devices.(9) The device according to (7) or (8), wherein a transmission frequency of a signal transmitted from the wireless communication unit to the first device is an uplink (UL) frequency in wireless communication between the device and a higher-level device, and wherein a transmission frequency of a signal transmitted from the first device to the wireless communication unit is also the UL frequency. (10) The device according to any of (1) to (9), wherein the DL signal includes a data request signal, and wherein the control unit, when the wireless communication unit receives a DL signal including the data request signal or a relay signal thereof, transmits an UL relay signal 22 including the requested data to another device or transmits an UL signal including the requested data to a higher-level device. (11) The device according to any of (1) to (10), wherein the control unit controls the wireless communication unit to receive a low power synchronization signal (LP-SS) and a low power wake-up signal (LP-WUS) from a higher-level device, transition from a deep sleep state to an awake state, establish synchronization with the higher-level device, and then receive the DL signal. (12) The device according to (11), wherein the control unit controls the wireless communication unit so that, after the synchronization is established, the wireless communication unit transmits the LP-SS and the LP-WUS to another device located outside a communication area with the higher-level device. (13) The device according to (11) or (12), wherein a modulation method of the LP-SS includes an OOK (On Off Keying) modulation method, the higher-level device includes a base station, and the device establishes synchronization with the base station based on the LP-SS. (14) The device according to any of (1) to (13), wherein a modulation method of the outgoing signal and the relay signal transmitted by the wireless communication unit includes an OOK (On Off Keying) modulation method. (15) A communication method, wherein, when a device receives a DL (downlink) signal or a relay signal thereof, the device transmits an outgoing signal to a plurality of first devices after a first time has elapsed, and the first time includes a waiting time specific to the device.(16) A communication system comprising: a plurality of first devices; a plurality of second devices each communicating with a corresponding plurality of first devices among the plurality of first devices; and an upper device communicating with some of the second devices among the plurality of second devices, wherein, upon receiving a DL (downlink) signal from the upper device or a relay signal of the DL signal from another second device, the second device transmits an outgoing signal to the corresponding plurality of first devices after a first time has elapsed, the first time including a waiting time specific to the second device. (17) The communication system described in (16), wherein, upon receiving the outgoing signal from the second device, the first device transmits the outgoing signal to the second device by a backscattering method. (18) The communication system described in (16) or (17), wherein power consumption of the first device is smaller than power consumption of the second device. (19) The communication system according to (17) or (18), wherein the plurality of first devices are provided in a greenhouse, and the signal transmitted from the first device to the second device includes at least one of sensing data acquired in the greenhouse and data indicating operation details of the greenhouse. (20) The communication system according to any of (16) to (18), further comprising a server device that searches for a second device provided relative to a target object from the plurality of second devices.

[0202] 100 Communication system 1 Device 101 Wireless communication unit 102 Control unit 103 Memory unit 2 Device 2-1 Device 2-2 Device 2-3 Device 2-4 Device 2-5 Device 2-6 Device 201 Wireless communication unit 202 Control unit 203 Memory unit 21 Transmission signal 22 Relay signal 22-12 Relay signal 22-23 Relay signal 22-32 Relay signal 22-21 Relay signal 22-45 Relay signal 22-56 Relay signal 22-65 Relay signal 22-54 Relay signal 23 UL signal 3 Upper device 32 DL signal 4 Base station 41 Wireless communication unit 411 Transmission processing unit 412 Reception processing unit 413 Antenna 42 Memory unit 43 Control unit 5 Terminal device 5-1 Terminal device 5-4 Terminal device 51 Wireless communication unit 511 Transmission processing unit 512 Reception processing unit 52 Storage unit 53 Control unit 54 Input unit 55 Output unit 6 User 60 Target object 61 Terminal device 62 Server device 63 Network 9 Area 9-1 Area 9-2 Area 9-3 Area 9-4 Area 9-5 Area 9-6 Area T1 First time T2 Second time Tw Waiting time Tw-1 Waiting time Tw-2 Waiting time Tw-3 Waiting time Tw-4 Waiting time Tw-5 Waiting time Tw-6 Waiting time d1 Data

Claims

1. A device comprising: a wireless communication unit; and a control unit that controls the wireless communication unit so that, when the wireless communication unit receives a DL (downlink) signal or a relay signal thereof, the wireless communication unit transmits an outgoing signal to a plurality of first devices after a first time has elapsed, wherein the first time includes a waiting time specific to the device.

2. The device of claim 1, wherein the control unit controls the wireless communication unit so that, when the wireless communication unit receives the DL signal or its relay signal, the wireless communication unit transmits a relay signal to another device after a second time has elapsed, and the second time includes the waiting time.

3. The device of claim 2, wherein the waiting time is a time equal to or less than a predetermined time, the first time is the waiting time, and the second time is the sum of the predetermined time and the waiting time.

4. The device of claim 1, wherein the waiting time is calculated based on information specific to the device, and the information specific to the device includes a device ID.

5. The device of claim 1, wherein the waiting time is a time calculated based on information specific to the device, the relay signal includes a signal indicating the number of relays, and the information specific to the device includes the number of relays.

6. The device of claim 1, wherein the DL signal includes a provisioning signal, and the provisioning includes settings related to wireless communication.

7. The device according to claim 1, wherein the control unit controls the wireless communication unit to receive an outgoing signal from each of the plurality of first devices in response to an outgoing signal from the wireless communication unit to each of the plurality of first devices.

8. The device according to claim 7, further comprising a storage unit that stores data for each of the plurality of first devices obtained from the transmitted signal from each of the plurality of first devices.

9. The device according to claim 7, wherein the transmission frequency of the signal transmitted from the wireless communication unit to the first device is an UL (uplink) frequency in wireless communication between the device and a higher-level device, and the transmission frequency of the signal transmitted from the first device to the wireless communication unit is also the UL frequency.

10. The device of claim 1, wherein the DL signal includes a data request signal, and when the wireless communication unit receives a DL signal including the data request signal or a relay signal thereof, the control unit transmits a UL relay signal 22 including the requested data to another device or transmits a UL signal including the requested data to a higher-level device.

11. The device according to claim 1, wherein the control unit controls the wireless communication unit so that the wireless communication unit receives an LP-SS (Low Power Synchronization Signal) and an LP-WUS (Low Power Wake Up Signal) from a higher-level device, transitions from a deep sleep state to an awake state, establishes synchronization with the higher-level device, and then receives the DL signal.

12. The device described in claim 11, wherein the control unit controls the wireless communication unit so that, after the synchronization is established, the wireless communication unit transmits the LP-SS and the LP-WUS to another device located outside the communication area with the higher-level device.

13. The device according to claim 11, wherein the modulation method of the LP-SS includes an OOK (On Off Keying) modulation method, the higher-level device includes a base station, and the device establishes synchronization with the base station based on the LP-SS.

14. The device according to claim 1, wherein a modulation method for the outgoing signal and the relay signal transmitted by the wireless communication unit includes an OOK (On Off Keying) modulation method.

15. A communication method, comprising: when a device receives a DL (downlink) signal or a relay signal thereof, transmitting an outgoing signal to a plurality of first devices after a first time has elapsed, wherein the first time includes a waiting time specific to the device.

16. A communication system comprising: a plurality of first devices; a plurality of second devices, each of which communicates with a corresponding plurality of first devices among the plurality of first devices; and an upper device which communicates with some of the second devices among the plurality of second devices, wherein, upon receiving a DL (downlink) signal from the upper device or a relay signal of the DL signal from another second device, the second device transmits an outgoing signal to the corresponding plurality of first devices after a first time has elapsed, and the first time includes a waiting time specific to the second device.

17. The communication system according to claim 16, wherein, upon receiving an outgoing signal from the second device, the first device transmits the outgoing signal to the second device in a backscatter manner.

18. The communication system according to claim 16, wherein the power consumption of the first device is less than the power consumption of the second device.

19. The communication system described in claim 17, wherein the plurality of first devices are provided in a greenhouse, and the signal transmitted from the first device to the second device includes at least one of sensing data acquired in the greenhouse and data indicating the operation of the greenhouse.

20. The communication system according to claim 16, further comprising a server device that searches for a second device provided for a target object from the plurality of second devices.

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