Wireless power supply system and method

Abstract

This wireless power supply system 100 is provided with: a base station 500 that performs wireless power supply to a terminal 700; and a dynamic sleep control function part 42 that puts at least some functions of the base station 500 to sleep on the basis of traffic information flowing through the base station 500 and information relating to the necessity of the wireless power supply to the terminal.

Description

Wireless power supply system and method

[0001] The present disclosure relates to a wireless power supply technology that utilizes wireless communication.

[0002] In recent years, Society 5.0 has been proposed, which aims to realize a smart society by installing a huge number of IoT terminals in various places in everyday spaces and using a wide variety of sensing data (see Non-Patent Document 1).

[0003] To realize Society 5.0, a huge number of IoT devices will be required, and one of the problems is how to supply power to the devices. Energy harvesting (EH) technology, which gathers energy from the surrounding environment and uses it as power, has attracted attention as a technology to solve this problem (see Non-Patent Document 2).

[0004] Non-Patent Document 3 proposes a wireless power supply using wireless communication, which is one of the EH technologies and can stably supply power in various places. Non-Patent Document 4 also discloses a terminal that performs intermittent operation, periodically repeating normal operation and standby operation. A terminal that performs such intermittent operation can effectively utilize the minute power generated by wireless power supply.

[0005] On the other hand, to perform such wireless power supply, it is necessary to take into consideration the radio resources of the base station. In particular, it is necessary to take into consideration that the radio resources of the base station are already being used for transmitting and receiving data between the base station and the terminal. For example, wireless communication standards such as 4G and 5G adopt a multiple access method using Orthogonal Frequency Division Multiple Access (OFDMA) / Time Division Multiple Access (TDMA). Non-Patent Document 3 discloses a method of using RBs (Resource Blocks) in the OFDMA / TDMA method not only for wireless communication (data transmission and reception) but also for wireless power supply.

[0006] Furthermore, Non-Patent Document 3 proposes a method of wirelessly feeding power during specific times when the traffic volume is low, using surplus RBs other than those consumed for data transmission and reception.

[0007] On the other hand, it is desirable to save power by putting base station components to sleep during periods of relatively low traffic. Non-Patent Documents 5 and 6 disclose techniques for reducing the number of available radio resources and saving power by permanently putting a specific base station or a specific component within a base station, such as an RRH / RU (Remote Radio Head / Radio Unit), to sleep.

[0008] Cabinet Office, "Society 5.0", Internet, <https: / / www8.cao.go.jp / cstp / society5_0 / > Energy Harvesting Consortium, "What is Energy Harvesting?", Internet, <https: / / www.nttdata-strategy.com / ehc / about / > Y. Nakamoto, N. Hasegawa, T. Hirakawa and Y. Ohta, "A Study on OFDM Modulation Suitable for Wireless Power Transfer," 2022 Wireless Power Week (WPW), Bordeaux, France, 2022, pp. 21-24, doi: 10.1109 / WPW54272.2022.9853969. ABLIC Inc., "What is Intermittent Operation?", Internet, <https: / / www.ablic. Fujitsu, "Outdoor LTE Radio Base Station Equipment (eNodeB)," Internet, <https: / / www.fujitsu.com / downloads / JP / archive / imgjp / jmag / vol62-4 / paper11.pdf> NEC, "Development of Energy Efficiency Technology for Beyond 5G Base Stations," Internet, <https: / / jpn.nec.com / techrep / journal / g23 / n01 / pdf / 230108.pdf>

[0009] However, the method of Non-Patent Document 3 is inefficient because wireless power supply is performed at a predetermined time, and therefore wireless power supply cannot be performed at other times when the traffic volume is low. Also, the methods of Non-Patent Documents 5 and 6 put a specific base station into a fixed sleep state, and therefore cannot handle cases where wireless power supply from that specific base station should have been performed.

[0010] Therefore, an object of the present disclosure is to provide a wireless power feeding system that can efficiently feed power wirelessly based on information indicating the necessity of wireless power feeding.

[0011] In order to achieve the above object, the wireless power feeding system of the present disclosure employs a technique of putting at least some functions of a base station to sleep based on information regarding the necessity of wireless power feeding to a terminal.

[0012] Specifically, the wireless power supply system of the present disclosure includes a base station capable of wirelessly supplying power to a terminal, and a sleep control unit that puts at least some functions of the base station into sleep mode based on traffic information flowing through the base station and information regarding the need for wireless power supply to the terminal.

[0013] Specifically, the wireless power supply method of the present disclosure is a method for putting a base station that wirelessly supplies power to a terminal to sleep, and puts at least some functions of the base station to sleep based on traffic information flowing through the base station and information regarding the need for wireless power supply to the terminal.

[0014] This makes it possible to efficiently wirelessly feed power to the terminal while switching the range in which the terminal is put to sleep based on information regarding the necessity of wireless power feeding.

[0015] 2. The wireless power supply system according to claim 1, wherein the base station includes a plurality of wireless transceiver devices that wirelessly supply power to the terminal, and the sleep control unit puts one or more of the plurality of wireless transceiver devices to sleep based on the traffic information and information related to the necessity of the wireless power supply.

[0016] This makes it possible to switch the range in which power is to be put to sleep based on information relating to the necessity of wireless power feeding, and to efficiently feed wireless power to the terminal using an optimal wireless transceiver.

[0017] 3. The wireless power feeding system according to claim 1, wherein the terminal has frequency characteristics that increase internal power conversion efficiency when wirelessly powered at a predetermined frequency, the information regarding the necessity of wireless power feeding includes the frequency characteristics of the terminal, and the at least some functions that perform wireless power feeding at a frequency corresponding to the frequency characteristics of the terminal are excluded from the sleep state.

[0018] This allows power saving by putting some functions of the base station to sleep, while wireless power supply can be performed at an optimal frequency to terminals having various frequency characteristics.

[0019] The above disclosures can be combined as much as possible.

[0020] According to the present disclosure, it is possible to efficiently perform wireless power feeding based on information indicating the necessity of wireless power feeding.

[0021] FIG. 1 is a diagram illustrating an overview of a wireless power feeding system according to a first embodiment of the present disclosure. FIG. 1 is a diagram illustrating an overall configuration of a wireless power feeding system according to the first embodiment of the present disclosure. FIG. 2 is a diagram illustrating a wireless power feeding method in a related wireless power feeding system. FIG. 3 is a diagram illustrating a wireless power feeding method in a wireless power feeding system according to the first embodiment of the present disclosure. FIG. 4 is a diagram illustrating a configuration of a wireless power feeding system according to a second embodiment of the present disclosure. FIG. 5 is a diagram illustrating a configuration of a wireless power feeding system according to a third embodiment of the present disclosure. FIG. 6 is a diagram illustrating a configuration of a wireless power feeding system according to a fourth embodiment of the present disclosure. FIG. 7 is a diagram illustrating a configuration of a wireless power feeding system according to a sixth embodiment of the present disclosure. FIG. 8 is a diagram illustrating a configuration of a wireless power feeding system according to a seventh embodiment of the present disclosure. FIG. 9 is a diagram illustrating sleep control of a wireless power feeding system according to an eighth embodiment of the present disclosure. FIG. 10 is a diagram illustrating sleep control of a wireless power feeding system according to a tenth embodiment of the present disclosure. FIG. 11 is a sequence diagram of a wireless power feeding system according to an eleventh embodiment of the present disclosure. FIG. 12 is a flowchart illustrating processing executed by a dynamic sleep control function unit according to a twelfth embodiment of the present disclosure. FIG. 13 is a flowchart illustrating processing executed by a base station sleep control function unit according to a thirteenth embodiment of the present disclosure.

[0022] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. Note that the present disclosure is not limited to the embodiments shown below. These implementation examples are merely illustrative, and the present disclosure can be implemented in various forms with various modifications and improvements based on the knowledge of those skilled in the art. Note that components with the same reference numerals in this specification and drawings indicate the same components.

[0023] [First embodiment] A wireless power feeding system 100 according to a first embodiment of the present disclosure will be described with reference to Fig. 1 to Fig. 3. In this embodiment, a basic configuration of the wireless power feeding system will be described. Fig. 1 describes an overview of the wireless power feeding system 100.

[0024] The wireless power supply system 100 wirelessly supplies power based on requests from terminals, other functional units, or external devices. The terminals are, for example, IoT terminals. The wireless power supply system 100 employs a highly efficient scheduling technique that simultaneously achieves power saving, wireless communication, and wireless power supply by dynamically putting base stations to sleep based on wireless power supply requests (wireless power supply information) and traffic predictions. Figure 1 shows the minimum functions required to realize such a highly efficient scheduling technique based on a 5G wireless network. Furthermore, the technique disclosed herein is applicable to any wireless network to which sleep technology can be applied, not limited to 5G.

[0025] The wireless power feeding system 100 mainly includes a 5G core 200, a wireless power feeding controller 300, a RAN (Radio Access Network) controller 400, and a base station 500. The base station 500 includes a CU / DU (Central Unit / Distributed Unit) 51 and an RU (Radio Unit) 52. The 5G core 200 performs relay processing of communication data transmitted from the base station 500 (CU / DU 51).

[0026] The wireless power supply controller 300 includes a wireless power supply request control function unit 31. The wireless power supply request control function unit 31 calculates, for a group of terminals under the control of the RU 52 of the base station 500, how much power each terminal needs, and how much power all terminals need in total. The wireless power supply request control function unit 31 transmits the calculation result to the RAN controller 400 as a wireless power supply request. The function of the wireless power supply controller 300 may be provided within the RAN controller 400. Note that in this embodiment, the group of terminals under the control of the RU 52 is omitted for simplicity. Furthermore, the wireless power supply request control function unit 31 acquires information indicating how much power the terminal currently needs, directly from the terminal requiring wireless power supply or indirectly via another function unit.

[0027] The RAN controller 400 includes a traffic prediction function unit 41 and a dynamic sleep control function unit 42. The traffic prediction function unit 41 predicts traffic that will occur in the base station 500.

[0028] The dynamic sleep control function unit 42 performs dynamic sleep control based on traffic prediction and dynamic sleep control based on wireless power feeding requests. These dynamic sleep controls may be performed independently, or may be performed together by synchronizing the traffic prediction and the wireless power feeding request and inputting them simultaneously to the dynamic sleep control function unit 42. When the radio resources consumed by the predicted traffic demand and wireless power feeding request are small and there are surplus resource blocks (RBs) of the base station 500, the dynamic sleep control function unit 42 appropriately executes the dynamic sleep function according to the amount of surplus RBs.

[0029] The dynamic sleep control function unit 42 controls the sleep of the base station 500 based on "wireless power supply information," "future traffic information," and "current base station sleep state information," which will be described later.

[0030] Specifically, when there are relatively few remaining RBs, the dynamic sleep control function unit 42 controls the base station 500 to perform symbol / slot sleep. Here, symbol / slot sleep refers to turning off a power amplifier (PA) and stopping quiescent current in a time domain in an RB of an OFDMA / TDMA (Orthogonal Frequency Division Multiple Access / Time Division Multiple Access) system where there are no control signals or user data. For example, significant power savings can be expected by setting an off time in advance during times when communication traffic volume is low.

[0031] Furthermore, when there are relatively many RBs remaining, the dynamic sleep control function unit 42 controls the base station 500 to perform MIMO (Multiple Input Multiple Output, antenna) sleep. Here, MIMO sleep refers to stopping RF (Radio Frequency) antenna elements in MIMO or Massive MIMO. In MIMO, if there is no correlation between the propagation path characteristics and the fading characteristics, the transmission capacity increases in proportion to min(M, N), where M is the number of transmitting antenna elements and N is the number of receiving antenna elements. In consideration of these MIMO characteristics, MIMO sleep achieves power saving by stopping the RF antenna of the transmitting base station and reducing the number of operating antenna elements.

[0032] Furthermore, the dynamic sleep control function unit 42 controls the base station 500 to perform cell sleep when RBs are rarely used. For example, the dynamic sleep control function unit 42 may power off the RU 52 unit-by-unit or all units as a form of cell sleep. Here, cell sleep refers to stopping all digital circuits, including the PA, in the RU during periods of low communication traffic. In other words, cell sleep saves power by powering down the RU itself. Cell sleep is applicable in situations where multiple base stations or RUs cover the same communication area. For example, there are small cells built overlapping a macro cell. In this case, when traffic is low, sleep is achieved by transferring traffic within the small cell to the macro cell and then powering down the base stations (RUs) that make up the small cell. Furthermore, base station overlap may not only be between macro and small cell base stations, but also between different communication standards. For example, if the communication areas of local 5G and Wi-Fi (Wireless Fidelity, registered trademark) overlap, it is possible to concentrate communications on one and put the other to sleep.

[0033] The CU / DU 51 includes a base station sleep control function unit 51A and an RB scheduling processing function unit 51B.

[0034] The base station sleep control function unit 51A executes sleep in accordance with dynamic sleep control by the dynamic sleep control function unit 42 of the RAN controller 400. In the case of cell sleep, the base station sleep control function unit 51A transfers communication within the cell to another cell and then turns off the power. Specifically, when executing cell sleep on a unit basis of RUs 52, the base station sleep control function unit 51A transfers communication to another RU 52 within the base station 500 and then turns off the power of that RU 52. On the other hand, when executing cell sleep for all RUs 52 within the base station 500, the base station sleep control function unit 51A transfers communication to another base station 500 and then turns off the power of all RUs 52.

[0035] In the case of sleep other than cell sleep, for example, MIMO sleep, the base station sleep control function unit 51A transmits a sleep instruction to the RU 52.

[0036] The RB scheduling processing function unit 51B receives a communication request and a wireless power supply request and determines an RB to be used. The RB scheduling processing function unit 51B can divide wireless communication and wireless power supply in frequency as well as time. By dividing the frequency, wireless resources with good frequency characteristics for the terminal can be used for power supply. When allocating wireless resources to wireless power supply and wireless communication by time division, modulation techniques such as those used in Non-Patent Document 3 can be applied.

[0037] The RU 52 comprises an RU sleep control function unit 52A and a radio transmission / reception function unit 52B. The RU sleep control function unit 52A executes MIMO sleep and symbol / slot sleep based on instructions from the CU / DU 51. The radio transmission / reception function unit 52B includes electronic circuits such as a power amplifier and an antenna unit at the radio transmitting end. The radio transmission / reception function unit 52B realizes communication or power supply using appropriate radio resources based on the scheduling of the RB scheduling processing function unit 51B.

[0038] As described above, the wireless power feeding system 100 includes: a base station 500 that wirelessly feeds power to a terminal 700; and a dynamic sleep control function unit 42 that puts at least some of the functions of the base station 500 into sleep mode based on traffic information flowing through the base station and information regarding the need for wireless power feeding to the terminal.

[0039] In this embodiment, the dynamic sleep control function unit 42 dynamically controls the sleep state of the base station 500 based on a wireless power feeding request. Therefore, even when the base station 500 is in sleep mode, wireless power feeding can be performed at an optimal frequency for terminals with various frequency characteristics. In particular, intermittent operation terminals can be stably operated even at night. In other words, even during a forced sleep period at night, the number of terminals operating intermittently within a predetermined time period can be maximized in a group of intermittent operation terminals.

[0040] Next, the overall configuration of a wireless power supply system 100 for realizing this embodiment will be described with reference to Fig. 2. The wireless power supply system 100 is configured with an external data network 600, a 5G core 200, one or more wireless power supply controllers 300, a RAN controller 400, one or more base stations 500, and a group of terminals 700. The base station 500 also includes one or more RUs 52.

[0041] In this way, there may be provided a plurality of each of the wireless power supply controller 300, the base station 500, and the RU 52. Although the following description may be given of a single wireless power supply controller 300, the base station 500, and the RU 52, the technology of the present disclosure also functions without any problems in a configuration in which a plurality of each is provided.

[0042] The external data network 600 is a network that has the function of delivering communication data sent from the 5G core 200 to an appropriate destination. This corresponds to the conventional Internet or a private network.

[0043] The 5G core 200 is a core network in the 5G standard, and relays communication data sent from the base station 500 to an external data network 600 or other base stations 500.

[0044] The wireless power feeding controller 300 is a device that identifies a terminal 700 that requires wireless power feeding and transmits a wireless power feeding request instruction to each base station 500 so that the terminal 700 is supplied with appropriate power. The wireless power feeding controller 300 may be the same as an existing wireless power feeding controller. The functions of the wireless power feeding controller 300 may be transferred to the RAN controller 400, and the controllers may be integrated and centralized.

[0045] The RAN controller 400 is a device that manages the sleep of each of the subordinate base stations 500. There may be a plurality of base stations 500 managed by the RAN controller 400, or there may be only one base station 500. The detailed configuration and functions of the RAN controller 400 will be described later.

[0046] The base station 500 is a communication device that provides a wireless access network and enables subordinate terminals 700 to transmit data via wireless communication. The CU / DU / RU (Central Unit / Distributed Unit / Radio Unit) of the base station 500 may be separate or integrated. Furthermore, there may be multiple RUs 52 or only one RU 52. When multiple RUs 52 are present, their coverage areas may or may not overlap, as shown in the figure. Furthermore, multiple base stations 500 may cover the same area or different areas. In summary, there are no limitations on the number or configuration of the base stations 500. The detailed configuration and functions of the base station 500 as an example will be described later.

[0047] The terminal 700 is a device that transmits data wirelessly and has the function of using communication radio waves not only for transmitting and receiving data but also for power. The terminal 700 may have only the function of transmitting and receiving data, or may have the function of using radio waves from base stations as power without directly communicating with the base station. The terminal 700 may be a device equipped with multiple types of energy harvesting technologies that use communication radio waves as power, or may be a hybrid type with a battery. There are no particular limitations on the power supply configuration or operating configuration of the terminal 700, but it must at least have a built-in function for using communication radio waves as power. Regarding power conversion of communication radio waves, the terminal 700 may use communication radio waves leaking to other terminals 700, or may use only communication radio waves addressed to itself. Two types of communication radio waves are assumed: radio waves for transmitting and receiving data and radio waves solely for power supply (wireless power supply).

[0048] Furthermore, the base station 500 does not necessarily need to transmit and receive data to and from all of the subordinate terminals 700. In other words, the base station 500 is configured to wirelessly feed power not only to the terminals 700 that directly transmit and receive data to and from the base station 500, but also to the terminals 700 that do not directly transmit and receive data to and from the base station 500. In other words, the base station 500 can wirelessly feed power to the subordinate terminals 700 regardless of whether data is transmitted and received between the base station 500 and the subordinate terminals 700.

[0049] Next, the resource allocation method of this embodiment will be described with reference to Fig. 3. Fig. 3A is a diagram illustrating a wireless power feeding method in a related wireless power feeding system. Fig. 3B is a diagram illustrating a wireless power feeding method in the wireless power feeding system 100 according to the first embodiment.

[0050] Specifically, the terminal 700 has frequency characteristics that increase the internal power conversion efficiency when wirelessly powered at a specified frequency, the information regarding the need for wireless power supply includes the frequency characteristics of the terminal 700, and at least some of the functions that supply wireless power at a frequency corresponding to the frequency characteristics of the terminal 700 are excluded from the sleep mode.

[0051] In the following description, it is assumed that the base station 500 includes multiple RUs 52. That is, the RUs 52 in the base station 500 are configured with multiple units having various bandwidths. Furthermore, each terminal 700 has different frequency characteristics, and power supply efficiency is maximized by wireless power supply at a specific frequency. The graphs in each figure show the status of wireless power supply from the RUs 52, with frequency on the horizontal axis and time on the vertical axis. Note that in the following description, a box surrounded by a solid line and filled in gray in the graph indicates a box that is being used for wireless power supply. Furthermore, a box surrounded by a solid line and not filled in in the graph indicates a box that is not being used for wireless power supply. Furthermore, a box surrounded by a dotted line indicates a sleep state.

[0052] In the wireless power supply method in the related wireless power supply system shown in Fig. 3A, a base band unit (BBU) or a control unit (CU / DU) turns off the power supply of one or more units of an RU in a fixed manner during stable low traffic periods at night. The figure shows an example in which the power supply of the third and fourth units is turned off.

[0053] However, if the RU unit is permanently powered off, it becomes impossible to supply power using radio resources with good frequency characteristics depending on the frequency characteristics of the terminal. In the case of Fig. 3A, it is impossible to supply power to terminals 3 and 4 efficiently.

[0054] In this way, when a base station is put into sleep mode on an RU-by-RU basis, wireless power feeding can only be performed among a limited number of units. Therefore, it is necessary to prioritize units with good frequency characteristics for the terminal. Therefore, the wireless power feeding system 100 of this embodiment dynamically switches units in response to a power feeding request.

[0055] 3B shows an example of a power supply method when the number of units (number of RUs 52) that can be operated simultaneously is 2. In the graph, frequency bands in which the power conversion efficiency of each terminal 700 improves are indicated by hatching.

[0056] Specifically, in the wireless power supply system 100 of this embodiment, in the period of time T1, in response to a power supply request from terminal 1 and terminal 2, the power of units 1 and 2 is turned on and the power of units 3 and 4 is turned off.

[0057] During time T2, in response to power supply requests from terminals 1, 2, and 3, units 1 and 3 are powered on and units 2 and 4 are powered off. In this case, the power supply efficiency for terminal 2 decreases, but when power is supplied to terminal 1, a small amount of power is also supplied to terminal 2.

[0058] During the time period T3, in response to power supply requests from terminals 2 and 3, units 2 and 3 are powered on and units 1 and 4 are powered off.

[0059] During the time period T4, in response to power supply requests from terminals 2, 3, and 4, units 2, 3, and 4 are powered on and unit 1 is powered off.

[0060] In this way, in this embodiment, wireless power feeding is performed taking into consideration the frequency characteristics of the terminal 700, so power feeding efficiency is increased and power can be saved more than when the terminal 700 is in a fixed sleep state.

[0061] Second Embodiment Next, a wireless power feeding system 100 according to a second embodiment will be described with reference to Fig. 4. The wireless power feeding system 100 according to the second embodiment basically has the same configuration as that described in the first embodiment. Specifically, the wireless power feeding system 100 includes a 5G core 200, a wireless power feeding controller 300, a RAN controller 400, a base station 500, and a terminal 700. Below, the functions of each functional unit will be mainly described in more detail.

[0062] The 5G core 200 includes a traffic statistics information function unit 21 and an other function unit 22. The traffic statistics information function unit 21 measures the amount of traffic flowing through the 5G core 200 and stores the measured amount as traffic information. The traffic statistics information function unit 21 provides traffic information to the RAN controller 400 in response to a request from the RAN controller 400 or periodically. The traffic statistics information function unit 21 may be configured in the same manner as existing technology for processing traffic information. The other function unit 22 includes functions required by the 5G core 200 in addition to the functions of the traffic statistics information function unit 21. The other function unit 22 may be configured in the same manner as existing technology.

[0063] The wireless power feeding controller 300 includes a wireless power feeding request control function unit 31 and an other function unit 32. The wireless power feeding request control function unit 31 identifies the terminals 700 that require wireless power feeding among the terminals 700 under the control of the base station 500, and calculates the required power. When the wireless power feeding request control function unit 31 determines from the calculation result that wireless power feeding is required, it transmits a wireless power feeding request to the RAN controller 400. The wireless power feeding request (wireless power feeding information) includes information such as power feeding terminal information, the required power feeding amount, power feeding frequency characteristics, and the remaining time until intermittent operation. The other function unit 32 executes other functions that implement the wireless power feeding controller 300. The wireless power feeding request or wireless power feeding information is an example of "information regarding the need for wireless power feeding."

[0064] The RAN controller 400 includes a traffic prediction function unit 41, a dynamic sleep control function unit 42, a traffic statistics information collection function unit 43, and a sleep state information holding function unit 44. The CU / DU 51 of the base station 500 includes a base station sleep control function unit 51A, an RB scheduling processing function unit 51B, and a traffic statistics information function unit 51C. The RU 52 of the base station 500 includes an RU sleep control function unit 52A and a radio transmission / reception function unit 52B. The function of the RU sleep control function unit 52A may be provided on the CU / DU 51 side.

[0065] The traffic statistics information collection function unit 43 collects past and present traffic information from the traffic statistics information function unit 51C of the 5G core 200 and each base station 500. The traffic statistics information collection function unit 43 may collect past and present traffic information using a function similar to that of existing technology.

[0066] The traffic prediction function unit 41 predicts current and future traffic demands based on the traffic information collected by the traffic statistical information collection function unit 43. The traffic prediction function unit 41 may predict current and future traffic demands using a function similar to that of existing technology.

[0067] The sleep state information holding function unit 44 has a function of holding the sleep state of the base station 500 sent from the base station sleep control function unit 51A of the base station 500 in the RAN controller 400. It is optional whether or not to provide the sleep state information holding function unit 44. If the sleep state information holding function unit 44 is not provided, the sleep state information is sent directly from the base station 500 to the dynamic sleep control function unit 42.

[0068] The dynamic sleep control function unit 42 has a function of determining whether or not the base station 500 can sleep based on three pieces of input information. Here, the three pieces of input information are "wireless power supply information" sent from the wireless power supply request control function unit 31 in the wireless power supply controller 300, "future traffic information" sent from the traffic prediction function unit 41, and "current base station sleep state information" acquired from the sleep state information holding function unit 44. In addition, the dynamic sleep control function unit 42 transmits the calculated and determined sleep control to the base station sleep control function unit 51A of the base station 500. Furthermore, the dynamic sleep control function unit 42 transmits information on terminals requiring wireless power supply and required power information to the RB scheduling processing function unit 51B of the base station 500.

[0069] Traffic statistics information function unit 51C observes the current and past traffic volumes flowing through base station 500 and transmits the observed volumes as traffic information to traffic statistics information collection function unit 43 of RAN controller 400. Here, the traffic volume flowing through base station 500 includes not only the traffic volume related to data transmission and reception with terminal 700 but also various traffic volumes such as the traffic volume on lines upstream of base station 500.

[0070] The base station sleep control function unit 51A uses sleep control information sent from the dynamic sleep control function unit 42 of the RAN controller 400 and sleep control information sent from the RB scheduling processing function unit 51B to perform sleep control of the base station 500. As described above, the sleep control of the base station 500 includes symbol / slot sleep, MIMO sleep, and cell sleep.

[0071] When the sleep control information sent from the RAN controller 400 indicates cell sleep, the base station sleep control function unit 51A executes cell sleep. Specifically, when putting all units of the RU 52 to sleep, the cell sleep is achieved by migrating the communication currently being performed within the base station 500 by the CU, and then turning off the power of the DU and the entire RU. At this time, the CU itself also enters a low-power consumption mode. Cell sleep may be achieved using a function similar to existing technology.

[0072] When the sleep control information sent from RAN controller 400 is symbol / slot sleep or MIMO sleep, base station sleep control function unit 51A transmits the sleep control information to RU sleep control function unit 52A of RU 52.

[0073] The RB scheduling processing function unit 51B allocates RBs based on a wireless power feeding request transmitted from the RAN controller 400 and a communication request generated under the control of the base station 500. A general RB scheduling processing function unit according to existing technology allocates RBs remaining in wireless communication to wireless power feeding in a time-division manner. In contrast, the RB scheduling processing function unit 51B according to this embodiment allocates wireless power taking into account the frequency characteristics of each terminal 700 and frequency division. When the RB scheduling processing function unit 51B determines that any of symbol / slot sleep, MIMO sleep, and cell sleep is additionally possible by devising a communication / wireless power feeding allocation method, it notifies the base station sleep control function unit 51A of this as sleep control information.

[0074] The RU sleep control function unit 52A performs either MIMO sleep or symbol / slot sleep based on the sleep control information sent from the base station sleep control function unit 51 A. Either sleep mode performed by the RU sleep control function unit 52A turns off the power of electronic circuit devices, antenna devices, etc., such as power amplifiers that constitute the wireless transceiver.

[0075] The wireless transmission / reception function unit 52B appropriately puts the component devices to sleep based on the sleep control sent from the RU sleep control function unit 52A, and also performs wireless communication and wireless power supply based on the schedule assigned by the RB scheduling processing function unit 51B.

[0076] The terminal 700 includes at least a wireless power supply function unit 71 and a communication function unit 72. The communication function unit 72 is used for transmitting and receiving data to and from the terminal 700. The wireless power supply function unit 71 has a function of converting any or all of leakage radio waves, communication radio waves addressed to the terminal 700, and wireless power supply radio waves into electric power and utilizing the converted power.

[0077] As described above, in this embodiment, the dynamic sleep control function unit 42 dynamically controls the sleep state of the base station 500 based on a wireless power feeding request. Therefore, even when the base station 500 is in sleep mode, wireless power feeding can be performed at an optimal frequency to terminals with various frequency characteristics. In particular, intermittent operation terminals can be stably operated even at night. In other words, even during a forced sleep period at night, the number of terminals operating intermittently within a predetermined time period can be maximized in a group of intermittent operation terminals.

[0078] In addition, by dynamically putting the base station to sleep based on wireless power supply requests and traffic predictions, it is possible to achieve power saving and highly efficient wireless communication and wireless power supply.

[0079] [Third Embodiment] Next, a wireless power feeding system 101 according to a third embodiment will be described with reference to Fig. 5. Fig. 5 is a diagram illustrating the configuration of the wireless power feeding system 101. The wireless power feeding system 101 does not include a wireless power feeding controller, and the function of the wireless power feeding controller is integrated into the RAN controller 401. Specifically, the RAN controller 401 includes a wireless power feeding request control function unit 45.

[0080] The functions of each functional unit in this embodiment are the same as those in the above-described embodiment. Even in this embodiment, even when the base station 500 is in sleep mode, wireless power feeding can be performed at an optimal frequency to terminals with various frequency characteristics. Furthermore, by dynamically putting the base station to sleep based on a wireless power feeding request and traffic prediction, power saving and highly efficient wireless communication and wireless power feeding can be achieved.

[0081] [Fourth Embodiment] Next, a wireless power supply system 101 according to a fourth embodiment will be described with reference to Fig. 6. Fig. 6 is a diagram illustrating the configuration of a wireless power supply system 102. The wireless power supply system 102 does not include a RAN controller, and the functions of the RAN controller are integrated into a wireless power supply controller 302. Specifically, the wireless power supply controller 302 includes a dynamic sleep control function unit 33, a traffic statistics information collection function unit 34, and a sleep state information storage function unit 35.

[0082] The functions of each functional unit in this embodiment are the same as those in the above-described embodiment. Even in this embodiment, even when the base station 500 is in sleep mode, wireless power feeding can be performed at an optimal frequency to terminals with various frequency characteristics. Furthermore, by dynamically putting the base station to sleep based on a wireless power feeding request and traffic prediction, power saving and highly efficient wireless communication and wireless power feeding can be achieved.

[0083] Fifth Embodiment Next, a wireless power feeding system 103 according to a fifth embodiment will be described with reference to Fig. 7. Fig. 7 is a diagram illustrating the configuration of the wireless power feeding system 103. In this embodiment, the RU 54 does not have an RU sleep control function unit, and the CU / DU 53 has an RU sleep control function unit 53A.

[0084] The functions of each functional unit in this embodiment are the same as those in the above-described embodiment. Even in this embodiment, even when the base station 503 is in sleep mode, wireless power feeding can be performed at an optimal frequency to terminals with various frequency characteristics. Furthermore, by dynamically putting the base station to sleep based on a wireless power feeding request and traffic prediction, power saving and highly efficient wireless communication and wireless power feeding can be achieved.

[0085] Sixth Embodiment Next, a wireless power supply system 104 according to a sixth embodiment will be described with reference to Fig. 8. Fig. 8 is a diagram illustrating the configuration of the wireless power supply system 104. In this embodiment, the RAN controller 404 is not provided with a sleep state information storage function unit.

[0086] As described above, in this embodiment, since a sleep state information holding function unit is not provided, the RAN controller 400 cannot always grasp the sleep state of each base station 500. For this reason, the dynamic sleep control function unit 46 in this embodiment has a function of inquiring of the base station 500 about its current sleep state before starting processing in response to a traffic prediction and a wireless power feeding request. Specifically, when the dynamic sleep control function unit 46 sends an inquiry about the sleep state to the base station sleep control function unit 51A, information about the sleep state is returned from the base station sleep control function unit 51A to be input to the dynamic sleep control function unit 46.

[0087] Other functions of the functional units in this embodiment are the same as those in the above-described embodiment. In this embodiment, even when the base station 500 is in sleep mode, wireless power feeding can be performed at an optimal frequency to terminals with various frequency characteristics. Furthermore, by dynamically putting the base station to sleep based on a wireless power feeding request and traffic prediction, power saving and highly efficient wireless communication and wireless power feeding can be achieved.

[0088] [Seventh Embodiment] Next, a wireless power supply system 105 according to a seventh embodiment will be described with reference to Fig. 9. Fig. 9 is a diagram illustrating the configuration of the wireless power supply system 105. In this embodiment, the RAN controller 405 does not have a dynamic sleep control function unit, and the CU / DU 55 has a dynamic sleep control function unit 55A.

[0089] The functions of each functional unit in this embodiment are the same as those in the above-described embodiment. Even in this embodiment, even when the base station 505 is in sleep mode, wireless power feeding can be performed at an optimal frequency to terminals with various frequency characteristics. Furthermore, by dynamically putting the base station to sleep based on a wireless power feeding request and traffic prediction, power saving and highly efficient wireless communication and wireless power feeding can be achieved.

[0090] [Eighth Embodiment] Next, a sleep control method according to an eighth embodiment will be described with reference to Fig. 10. The wireless power supply system according to this embodiment includes multiple base stations 500, and the figure shows base stations 500A and 500B as representatives. In addition, this embodiment will describe cell sleep and symbol / slot sleep. Cell sleep here refers to executing sleep on a base station basis or for all RU units possessed by the base station. An RB may be used for either wireless communication or wireless power supply. The entire base station 500 functions as "at least a part of the functions of a base station."

[0091] As shown in the figure, when different base stations 500 use different frequency bands and cover the same area, sleep can be executed on a base station 500 basis by consolidating communication and wireless power supply in one of the base stations 500 (cell sleep). The figure shows an example in which communication and wireless power supply are consolidated in base station 500A and base station 500B is put to sleep. Also, when only a certain frequency slot in an RB is not used, that frequency slot can also be put to sleep (symbol / slot sleep).

[0092] These sleep states are released when the traffic demand for wireless communication increases, or when the number of wireless power supply requests increases and RBs become insufficient. This embodiment also provides the same effects as the above-described embodiments.

[0093] [Ninth Embodiment] Next, a sleep control method according to a ninth embodiment will be described with reference to Fig. 11 . A base station 500 of a wireless power feeding system in this embodiment includes a plurality of RUs 52, and the figure shows RUs 521 and 522 as representatives. In this embodiment, cell sleep and symbol / slot sleep will be described in units of RUs. An RB may be used for either wireless communication or wireless power feeding. The RU 52 functions as a "wireless transceiver." The RU 52 functions as "at least a part of the functions of a base station."

[0094] Specifically, the base station 500 has a plurality of RUs 52 that wirelessly supply power to the terminal 700, and the dynamic sleep control function unit 42 puts one or more of the plurality of RUs 52 to sleep based on traffic information and information regarding the need for wireless power supply.

[0095] As shown in the figure, when different RUs 52 use different frequency bands and cover the same area, sleep can be performed on an RU 52 basis by aggregating the communication and wireless power supply of one of the RUs 52 (cell sleep on an RU 52 basis). The figure shows an example in which communication and wireless power supply are aggregated in RU 521 and RU 522 is put to sleep. Also, when only a certain frequency slot in an RB is not used, that frequency slot can also be put to sleep (symbol / slot sleep).

[0096] These sleep states are released when the traffic demand for wireless communication increases, or when the number of wireless power supply requests increases and RBs become insufficient. This embodiment also provides the same effects as the above-described embodiments.

[0097] [Tenth Embodiment] Next, a sleep control method according to a tenth embodiment will be described with reference to FIG. 12 . In this embodiment, the RU 52 of the base station 500 is equipped with multiple antennas, and the figure shows antennas 55A and 55B as representatives. In addition, in this embodiment, MIMO sleep on an antenna-by-antenna basis will be described. Here, when MIMO is used, by using multiple antennas, different information can be transferred using RBs of the same frequency and time (spatial multiplexing). The RBs may be used for either wireless communication or wireless power supply. The antennas function as "at least a part of the functions of the base station."

[0098] Although the figure shows a case where there are two antennas, the same applies to a case where there are three or more antennas. When traffic demand is low, all of the RBs used by antenna 55B can be supplemented by antenna 55A. In such a case, power saving can be achieved by putting antenna 55B to sleep. When traffic demand increases, antenna 55B is powered on again. This embodiment also achieves the same effects as the above-mentioned embodiments.

[0099] Eleventh Embodiment Next, a processing sequence of a wireless power feeding system according to an eleventh embodiment will be described with reference to Fig. 13. The processing sequence of the wireless power feeding system according to this embodiment is applicable to all of the embodiments described above.

[0100] Specifically, the wireless power supply method of the present disclosure is a wireless power supply method that puts a base station 500 that wirelessly supplies power to a terminal 700 to sleep, and puts at least some of the functions of the base station 500 to sleep based on traffic information flowing through the base station 500 and information regarding the need for wireless power supply to the terminal 700.

[0101] First, the RAN controller 400 collects traffic statistical information on the past and present traffic volume from the 5G core 200 and the base station 500, and predicts the current and future traffic volume (steps S1, S2, S3).

[0102] RAN controller 400 refers to and acquires sleep state information to determine whether base station 500 is currently in a sleep state, and if so, what state it is in (step S4). The sleep state information is referenced from within RAN controller 400 or base station 500.

[0103] The RAN controller 400 performs dynamic sleep processing using the wireless power supply request sent from the wireless power supply controller 300 (step S5), the traffic prediction result, and the sleep state information as inputs, and determines whether to put the components of the base station 500 into sleep mode (step S6).

[0104] In step S7, when putting the components of the base station 500 to sleep or changing the sleep state, the RAN controller 400 transmits sleep control information including an appropriate sleep instruction and a wireless power feeding request to the base station 500. On the other hand, in step S7, when not putting the components of the base station 500 to sleep or not changing the sleep state, the RAN controller 400 transmits only a wireless power feeding request to the base station 500.

[0105] The base station 500 analyzes the sleep control information sent from the RAN controller 400. Then, in step S8, in the case of cell sleep, that is, when sleep is executed for each base station 500 or for all RU units of the base station 500, the base station 500 migrates communication of the base station 500 to another base station 500 and then turns off the base station 500 (step S8). In the case of sleep for each RU unit, MIMO sleep, or symbol / slot sleep, the base station 500 executes sleep in an appropriate manner.

[0106] The base station 500 performs RB scheduling based on the wireless power supply request transmitted from the RAN controller 400 and the current communication request (step S9). Here, RB scheduling refers to a specific RB allocation method for determining which RBs, among those divided on the frequency and time axes, are to be used for communication / wireless power supply to which terminals. If the base station 500 determines that additional sleep in the RU is possible by devising a wireless power supply allocation method, it executes the sleep (step S10).

[0107] Based on the sleep control and scheduling, uplink and downlink wireless communications and downlink wireless power feeding are performed between the sleep-applied and non-applied base stations 500 and the communication terminals / power feeding terminals (step S11). The wireless power feeding system repeats the above processing.

[0108] [Twelfth Embodiment] Next, with reference to Fig. 14, a process executed by the dynamic sleep control function unit 42 according to a twelfth embodiment will be described. The process executed by the dynamic sleep control function unit 42 according to this embodiment is applicable to the dynamic sleep control function units according to all of the above-described embodiments. The dynamic sleep control function unit 42 may execute the process periodically or at random times. For example, the dynamic sleep control function unit 42 may execute the process when it receives a wireless power feeding request from the wireless power feeding controller 300.

[0109] In step S101, the dynamic sleep control function unit 42 sets a counter i to 1. Here, i indicates the i-th base station 500. In this embodiment, as shown below, the counter is updated from i to the total number N of base stations, and processing is executed for all base stations 500 under the control of the RAN controller 400 in one execution. However, the scope of the present disclosure is not limited to this, and processing may be executed for each base station 500.

[0110] In order for the dynamic sleep control function unit 42 to perform processing, traffic prediction information, base station sleep state information, and wireless power supply request information are required, so the dynamic sleep control function unit 42 first refers to and acquires these pieces of information. Specifically, in step S102, the dynamic sleep control function unit 42 refers to and acquires the traffic prediction information of the i-th base station 500. In addition, in step S103, the dynamic sleep control function unit 42 refers to and acquires the sleep state information of the i-th base station 500. In addition, in step S104, the dynamic sleep control function unit 42 refers to and acquires the wireless power supply request information.

[0111] In step S105, the dynamic sleep control function unit 42 determines whether or not the i-th base station 500 is currently in sleep mode, based on the above three pieces of information. In addition, in step S106, the dynamic sleep control function unit 42 determines whether or not there are sufficient radio resources for the i-th base station 500, based on the traffic prediction information and the wireless power supply request information. In other words, as a result of the determination by the dynamic sleep control function unit 42, the state of the i-th base station 500 is classified into four types (2 x 2) depending on whether or not it is sleeping and whether or not there are sufficient radio resources.

[0112] In step S107, the dynamic sleep control function unit 42 performs transmission processing for each classification. Specifically, sleep control information and wireless power supply request information are transmitted to the i-th base station 500. Whether or not cell sleep should be performed can also be determined from traffic prediction information, so if cell sleep is to be performed, the dynamic sleep control function unit 42 may directly perform sleep. Note that even when cell sleep is to be performed, the execution of sleep may be left to the base station sleep control function unit 51A of the base station 500. This flowchart shows an example in which the execution of sleep and detailed decisions on sleep are left to the base station sleep control function unit 51A of the base station 500.

[0113] In step S107, the dynamic sleep control function unit 42 determines whether the counter i is less than N. If it is determined that i is less than N (step S107: Yes), the dynamic sleep control function unit 42 adds 1 to the counter i and repeats the above process.

[0114] After performing the above process for all base stations 500, the dynamic sleep control function unit 42 ends the process.

[0115] [Thirteenth Embodiment] Next, with reference to Fig. 15 , a process executed by the base station 500 according to the thirteenth embodiment will be described. The process executed by the base station 500 according to this embodiment is applicable to the base stations according to all of the embodiments described above. The base station 500 may execute the process periodically or at random times. For example, the base station 500 may execute the process when base station sleep information is sent from the RAN controller 400.

[0116] In step S201, the base station sleep control function unit 51A determines whether the currently applied sleep mode is optimal based on the sleep control information received from the RAN controller 400. If it is determined that the currently applied sleep mode is not optimal (step S201: No), the base station sleep control function unit 51A changes the sleep mode. For example, if a unit of a frequency band optimal for the terminal 700 to be powered is in a sleep mode and another unit is in operation, the base station sleep control function unit 51A switches the operating unit to the optimal one. After changing the sleep mode, the base station sleep control function unit 51A notifies the RAN controller 400 of the sleep mode update in order to update the information.

[0117] Meanwhile, in step S203, the RB scheduling processing function unit 51B of the base station 500 executes RB scheduling based on the wireless power supply request from the RAN controller 400 and the actual traffic occurring under the control of the base station 500. The power supply request includes the frequency characteristics and intermittent operation requirements of the terminal 700, and these are taken into consideration during scheduling.

[0118] In step S204, the RB scheduling processing function unit 51B determines whether or not there are surplus radio resources. In other words, the RB scheduling processing function unit 51B determines whether or not any of symbol / slot sleep, MIMO sleep, and cell sleep is possible by devising a communication / wireless power supply allocation method.

[0119] When it is determined that any of the sleep modes is additionally possible (step S204: Yes), the RB scheduling processing function unit 51B notifies the base station sleep control function unit 51A of information indicating that the additional sleep mode is additionally possible as sleep control information. In step S206, after changing the sleep mode, the base station sleep control function unit 51A notifies the RAN controller 400 of the update of the sleep mode in order to update the information.

[0120] If it is determined that no additional sleep is possible (step S205: No), or after step S205, the base station sleep control function unit 51A appropriately drives the wireless transceiver equipment and performs wireless communication and wireless power supply based on the schedule.

[0121] The device of the present invention can also be realized by a computer and a program, and the program can be recorded on a recording medium or provided via a network. The program of the present disclosure is a program for causing a computer to realize each function of the device according to the present disclosure, and a program for causing a computer to execute each procedure of the method executed by the device according to the present disclosure.

[0122] 21: Traffic statistics information functional unit 22: Other functional units 31: Wireless power supply request control functional unit 32: Other functional units 33: Dynamic sleep control functional unit 34: Traffic statistics information collection functional unit 35: Sleep state information storage functional unit 41: Traffic prediction functional unit 42, 46, 55A: Dynamic sleep control functional unit 43: Traffic statistics information collection functional unit 44: Sleep state information storage functional unit 45: Wireless power supply request control functional unit 51, 53, 55: CU / DU 51A: Base station sleep control functional unit 51B: RB scheduling processing functional unit 51C: Traffic statistics information functional unit 52, 54, 521, 522: RU 52A, 53A: RU sleep control functional unit 52B: Wireless transmission / reception functional unit 55A, 55B: Antenna 100: Wireless power supply system 200: 5G core 300, 302: Wireless power supply controllers 400, 401, 404: RAN controllers 500, 503, 505, 500A, 500B: Base stations 600: External data network 700: Terminal 71: Wireless power supply function unit 72: Communication function unit

Claims

1. A wireless power feeding system comprising: a base station that performs wireless power feeding to a terminal; and a sleep control unit that puts at least some functions of the base station into a sleep state based on traffic information flowing through the base station and information regarding the necessity of wireless power feeding to the terminal.

2. The wireless power feeding system according to claim 1, wherein the base station includes a plurality of wireless transceivers that perform the wireless power feeding to the terminal, and the sleep control unit puts any one or more of the plurality of wireless transceivers into a sleep state based on the traffic information and the information regarding the necessity of wireless power feeding.

3. The wireless power feeding system according to claim 1 or 2, wherein the terminal has a frequency characteristic in which the internal power conversion efficiency is high in wireless power feeding at a predetermined frequency, the information regarding the necessity of wireless power feeding includes the frequency characteristic of the terminal, and at least some functions that perform wireless power feeding at a frequency corresponding to the frequency characteristic of the terminal are excluded from the target of the sleep state.

4. A wireless power feeding method for putting a base station that performs wireless power feeding to a terminal into a sleep state, the method including putting at least some functions of the base station into a sleep state based on traffic information flowing through the base station and information regarding the necessity of wireless power feeding to the terminal.

Images