Wireless communication system, central station, centralized control method, and centralized control program

Abstract

A wireless communication system according to an embodiment of the present invention collects, via a plurality of base stations, terminal position information indicating the position of each of terminals, power intensity information indicating the intensity of power received from each of the terminals, and state-of-charge information indicating the state of charge of a power storage battery of each of the terminals, calculates, on the basis of the collected terminal position information, the collected power intensity information and the collected state-of-charge information, a power to be allocated to each of the terminals of the base stations, calculates, on the basis of the calculated power to be allocated, a parameter that optimizes power utilization efficiency and band allocation to each of the terminals of the base stations so that while the power utilization efficiency of the entire system is increased, the power consumption is minimized, and controls the utilization efficiency of the transmission power of an RF signal that is to be transmitted, according to the calculated parameter, to each of the terminals from the base stations.

Description

[Technical Field]

[0001] The present invention relates to a wireless communication system, a central station, a central control method, and a central control program. [Background technology]

[0002] Conventionally, in a multi-user MIMO (Multiple Input Multiple Output) system, a technology has been known in which a plurality of terminals that perform wireless communication and a plurality of terminals that perform charging are grouped together to achieve both data transmission by RF (Radio Frequency) signals and energy harvesting (see, for example, Non-Patent Document 1). [Prior art documents] [Non-patent literature]

[0003] [Non-Patent Document 1] J. Rubio and APIserte, "User grouping and resource allocation in multiuser MIMO systems under SWIPT," EURASIP Journal on Wireless Communications and Networking 2019. Summary of the Invention [Problem to be solved by the invention]

[0004] However, conventionally, it has not been possible to reduce the power consumption of a base station in a multi-user MIMO system, and there have been cases where the power utilization efficiency of the entire system has not been sufficiently improved.

[0005] The present invention has been made in consideration of the above-mentioned problems, and aims to provide a wireless communication system, a central station, a central control method, and a central control program that enable data transmission via RF signals and energy harvesting to be compatible, while optimizing the power utilization efficiency of the entire wireless communication system. [Means for solving the problem]

[0006] A wireless communication system according to an embodiment of the present invention includes: In a wireless communication system comprising a central station that centrally controls a plurality of base stations each capable of accommodating a plurality of terminals, and wherein the plurality of terminals and the base stations perform multi-user MIMO wireless communication, the terminals have an information decoder that decodes information that becomes data from an RF signal received from the base station, an energy harvester that charges a storage battery by energy harvesting using the RF signal received from the base station, and a switching unit that switches to supply the RF signal received from the base station to either the information decoder or the energy harvester, and the base station groups the plurality of terminals so that they belong to either an information transmission group that transmits information that becomes data or an energy harvesting group that charges a storage battery by energy harvesting, based on the remaining amount information acquired by the remaining amount information acquisition unit and the presence or absence of data to be transmitted to the terminals by RF signals. and a control unit that controls bandwidth allocation and transmission power of RF signals to be transmitted to each of the terminals for each group grouped by the grouping unit, wherein the central station comprises a collection unit that collects, via the plurality of base stations, terminal location information indicating the location of each of the terminals, power strength information indicating the received power strength from each of the terminals, and remaining capacity information of the storage batteries of each of the terminals; an allocation power calculation unit that calculates an allocation power of each of the base stations to each of the terminals based on the terminal location information, power strength information, and remaining capacity information collected by the collection unit; a parameter calculation unit that calculates parameters that optimize bandwidth allocation and power utilization efficiency of each of the base stations to each of the terminals based on the allocation power calculated by the allocation power calculation unit, so as to minimize power consumption while increasing power utilization efficiency of the entire system; and a utilization efficiency control unit that controls utilization efficiency of the transmission power of RF signals to be transmitted by each of the base stations to each of the terminals in accordance with the parameters calculated by the parameter calculation unit.

[0007] Furthermore, a central station according to one embodiment of the present invention is a central station that centrally controls a plurality of base stations that each perform multi-user MIMO wireless communication with a plurality of terminals, and includes: a collection unit that collects, via the plurality of base stations, terminal location information indicating the location of each of the terminals, power strength information indicating the received power strength from each of the terminals, and remaining amount information indicating the remaining amount of power stored in a storage battery of each of the terminals; an allocation power calculation unit that calculates an allocation power of each of the base stations to each of the terminals based on the terminal location information, power strength information, and remaining amount information collected by the collection unit; a parameter calculation unit that calculates parameters that optimize bandwidth allocation and power utilization efficiency of each of the base stations to each of the terminals based on the allocation power calculated by the allocation power calculation unit, so as to minimize power consumption while improving power utilization efficiency of the entire system; and a utilization efficiency control unit that controls the utilization efficiency of the transmission power of an RF signal that each of the base stations transmits to each of the terminals in accordance with the parameters calculated by the parameter calculation unit.

[0008] Furthermore, a centralized control method according to one embodiment of the present invention is a centralized control method for centrally controlling a plurality of base stations each performing multi-user MIMO wireless communication with a plurality of terminals, the centralized control method comprising the steps of: collecting, via the plurality of base stations, terminal location information indicating the location of each of the terminals, power strength information indicating the received power strength from each of the terminals, and remaining amount information indicating the remaining amount of power stored in a storage battery of each of the terminals; an allocation power calculation step of calculating an allocation power of each of the base stations to each of the terminals based on the collected terminal location information, power strength information, and remaining amount information; a parameter calculation step of calculating, based on the calculated allocation power, parameters that optimize bandwidth allocation and power usage efficiency of each of the base stations to each of the terminals so as to minimize power consumption while increasing the power usage efficiency of the entire system; and a utilization efficiency control step of controlling the utilization efficiency of the transmission power of an RF signal that each of the base stations transmits to each of the terminals in accordance with the calculated parameters. [Effects of the Invention]

[0009] According to the present invention, it is possible to optimize the power utilization efficiency of the entire wireless communication system while achieving both data transmission by RF signals and energy harvesting. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a diagram illustrating an overview of a wireless communication system according to an embodiment. [Figure 2] FIG. 2 is a functional block diagram illustrating functions of a terminal. [Figure 3] FIG. 2 is a functional block diagram illustrating functions of a base station. [Figure 4] FIG. 2 is a functional block diagram illustrating the functions of a central station. [Figure 5] 10 is a flowchart illustrating an example of the operation of the central station. [Figure 6] FIG. 2 is a diagram illustrating an example of a hardware configuration of a central station according to an embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0011] A wireless communication system according to an embodiment will be described below with reference to the drawings. Fig. 1 is a diagram showing an overview of a wireless communication system 1 according to an embodiment. The wireless communication system 1 according to an embodiment includes a central station that centrally controls a plurality of base stations 3, each capable of accommodating a plurality of terminals 2, and the plurality of terminals 2 and the base stations 3 perform multi-user MIMO wireless communication.

[0012] The terminals 2 are wireless terminals used by users for wireless communication. The terminals 2 may also be IoT (Internet of Things) terminals that communicate a small amount of data. The base stations 3 may be reflectors that relay radio waves. The central station 4 is configured to centrally control the multiple base stations 3.

[0013] Next, the functions of terminal 2, base station 3, and toll station 4 will be specifically explained with reference to FIGS.

[0014] Fig. 2 is a functional block diagram illustrating functions of the terminal 2. As shown in Fig. 2, the terminal 2 includes, for example, a plurality of antennas 20, a switching unit 21, an information decoder 22, a power information collecting unit 23, an energy harvester 24, a storage battery 25, a remaining power information notifying unit 26, and a location information notifying unit 27.

[0015] The switching unit 21 switches between supplying RF signals received from the base station 3 via, for example, a plurality of antennas 20 to either the information decoder 22 or the energy harvester 24 .

[0016] The information decoder 22 includes, for example, a radio converter 220, an AD converter 222, a demodulator / decoder 224, and an information bit detector 226, and has a function of decoding information that becomes data from an RF signal received from the base station 3.

[0017] For example, the wireless conversion unit 220 converts wireless signals received via the multiple antennas 20 into analog signals of a predetermined frequency, and outputs the analog signals to the AD conversion unit 222 and the power information collection unit 23.

[0018] The AD conversion unit 222 is an analog-to-digital conversion unit that converts the analog signal converted by the wireless conversion unit 220 into a digital signal.

[0019] The demodulation and decoding unit 224 demodulates the received data converted into a digital signal by the AD conversion unit 222 , performs error correction decoding, and outputs the demodulated data to the information bit detection unit 226 .

[0020] The information bit detector 226 detects information bits from the signal input from the demodulator / decoder 224 .

[0021] The power information collecting unit 23 collects power information of the received signal input to the information decoder 22 .

[0022] The energy harvester 24 charges the storage battery 25 by energy harvesting using an RF signal received from the base station 3.

[0023] The storage battery 25 is charged by the energy harvester 24 or the like, and supplies power to each component of the terminal 2.

[0024] The remaining amount information notification unit 26 performs processing to notify the base station 3 of remaining amount information indicating the remaining amount of power stored in the storage battery 25.

[0025] The location information notification unit 27 generates a notification signal for notifying the base station 3 of information (terminal location information) indicating the location of the own station (the terminal 2), and notifies the base station 3 of the generated notification signal via the antenna 20.

[0026] Fig. 3 is a functional block diagram illustrating functions of the base station 3. As shown in Fig. 3, the base station 3 includes, for example, a plurality of antennas 30, an information bit generation unit 31, a modulation and coding unit 32, a DA conversion unit 33, a wireless conversion unit 34, a wireless conversion unit 35, an AD conversion unit 36, a demodulation and decoding unit 37, an information bit detection unit 38, a power intensity detection unit 300, an obstacle information detection unit 302, an environmental information detection unit 304, a remaining capacity information acquisition unit 390, a grouping unit 392, and a control unit 394.

[0027] The information bit generator 31 generates information bits indicating data to be transmitted to the terminal 2 and outputs the generated information bits to the modulation and coding unit 32 .

[0028] The modulation and coding unit 32 performs error correction coding on the information bits generated by the information bit generation unit 31 , digitally modulates the information bits into a data signal, and outputs the data signal to the DA conversion unit 33 .

[0029] The DA conversion unit 33 converts the data signal digitally modulated by the modulation and coding unit 32 into an analog signal and outputs it to the radio conversion unit .

[0030] The radio conversion unit 34 converts the analog signal converted by the DA conversion unit 33 into a predetermined radio signal, and transmits it via the multiple antennas 30.

[0031] The radio conversion unit 35 converts radio signals received via the multiple antennas 30 into analog signals of a predetermined frequency, and outputs the analog signals to the AD conversion unit 36 ​​.

[0032] The AD conversion unit 36 ​​is an analog-to-digital conversion unit that converts the analog signal converted by the wireless conversion unit 35 into a digital signal.

[0033] The demodulation / decoding unit 37 demodulates the received data converted into a digital signal by the AD conversion unit 36 ​​, performs error correction decoding, and outputs the data to the information bit detection unit 38 and remaining amount information acquisition unit 390 .

[0034] The information bit detector 38 detects information bits from the signal input from the demodulator / decoder 37 .

[0035] The power intensity detection unit 300 detects the power intensity of signals received from each terminal 2 via the multiple antennas 30, and notifies the central station 4. For example, the power intensity detection unit 300 detects the gain of each multipath for each delay time. The power intensity detection unit 300 may also have a function to detect the distance from the terminal 2, the propagation loss between the terminal 2, and the like.

[0036] The obstacle information detection unit 302 is an image sensor such as a CMOS sensor that detects obstacles that affect communication with the terminals 2, and performs processing to notify the central station 4 of information indicating the detected obstacles. For example, the obstacle information detection unit 302 takes an image of an object located between the terminals 2.

[0037] The environmental information detection unit 304 detects the surrounding environment that may affect communication with the terminal 2, and notifies the central station 4 of environmental information indicating the detected surrounding environment.

[0038] The remaining amount information acquisition unit 390 acquires remaining amount information indicating the remaining amount of power stored in the storage battery 25 of each terminal 2 , and outputs the information to the grouping unit 392 .

[0039] The grouping unit 392 groups multiple terminals 2 so that they belong to either an information transmission group that transmits information that becomes data, or an energy harvesting group that charges the storage battery 25 by energy harvesting, based on the remaining amount information acquired by the remaining amount information acquisition unit 390 and the presence or absence of data to be transmitted to the terminal 2 by RF signal.

[0040] The control unit 394 controls each unit constituting the base station 3. For example, the control unit 394 controls the band allocation and transmission power of the RF signal to be transmitted to each terminal 2 for each group formed by the grouping unit 392.

[0041] The base station 3 is configured to have the function of transmitting to the central station 4, for example, the wireless quality status between the terminal 2 (propagation loss, fading environment, shadowing) and terminal location information indicating the location of the terminal 2 notified by the terminal 2.

[0042] Fig. 4 is a functional block diagram illustrating the functions of the central station 4. As shown in Fig. 4, the central station 4 includes, for example, a collection unit 40, an optimization processing unit 42, and a utilization efficiency control unit 44.

[0043] The collection unit 40 has, for example, a location information collection unit 402, a remaining amount information collection unit 403, a power intensity collection unit 404, an obstacle information collection unit 406, and an environment information collection unit 408. The collection unit 40 collects, via a plurality of base stations 3, terminal location information indicating the location of each terminal 2, power intensity information indicating the received power intensity from each terminal 2, and remaining amount information of the storage battery 25 of each terminal 2, and outputs the information to the optimization processing unit 42.

[0044] For example, the location information collection unit 402 collects terminal location information indicating the location of each terminal 2 transmitted from the base station 3, and outputs the information to the optimization processing unit .

[0045] The remaining capacity information collection unit 403 collects remaining capacity information of the storage battery 25 of each terminal 2 transmitted from the base station 3, and outputs it to the optimization processing unit .

[0046] The power intensity collecting unit 404 collects power information indicating the intensity of the received power from each terminal 2 transmitted from the base station 3, and outputs the information to the optimization processing unit .

[0047] The obstacle information collection unit 406 collects information indicating obstacles that affect communication with the terminal 2 and is transmitted from the base station 3, and outputs the information to the optimization processing unit .

[0048] The environmental information collection unit 408 collects environmental information indicating the surrounding environment that may affect communication with the terminal 2 and is transmitted from the base station 3, and outputs the collected information to the optimization processing unit .

[0049] The optimization processing unit 42 includes an allocated power calculation unit 420 and a parameter calculation unit 422, and performs processing to optimize the power utilization efficiency of the entire wireless communication system 1, and outputs the processing result to the utilization efficiency control unit 44.

[0050] For example, the allocated power calculation unit 420 calculates the allocated power for each terminal 2 of the base station 3 based on the terminal location information, power intensity information, and remaining amount information collected by the collection unit 40, and outputs the calculated power to the parameter calculation unit 422.

[0051] Based on the allocated power calculated by the allocated power calculation unit 420, the parameter calculation unit 422 calculates parameters that optimize bandwidth allocation and power utilization efficiency for each terminal 2 of the base station 3 so as to increase the power utilization efficiency of the entire system while minimizing power consumption, and outputs the calculated parameters to the utilization efficiency control unit 44.

[0052] For example, the parameter calculation unit 422 calculates parameters that optimize bandwidth allocation and power utilization efficiency for each terminal 2 of the base station 3 by changing the number of terminals 2 belonging to the energy harvesting group so as to minimize the power consumption of the entire system.

[0053] The utilization efficiency control unit 44 controls each base station 3 so as to control the utilization efficiency of the transmission power of the RF signal that each base station 3 transmits to each terminal 2 in accordance with the parameter calculated by the parameter calculation unit 422.

[0054] Next, we will explain an example of the operation of the central station 4. Fig. 5 is a flowchart showing an example of the operation of the central station 4. As shown in Fig. 5, for example, the central station 4 collects terminal location information, power intensity information, and remaining capacity information of each terminal 2 (S100).

[0055] Next, based on the collected terminal location information, power intensity information, and remaining capacity information of each terminal 2, central station 4 calculates the allocation power of each stream of multi-user MIMO for each terminal 2 that will transmit data (S102).

[0056] Next, the central station 4 calculates the allocated power for each terminal 2 that is not transmitting data and is requesting charging, based on the collected terminal location information, power intensity information, and remaining capacity information for each terminal 2 (S104).

[0057] Then, the central station 4 determines whether the power consumption of the entire wireless communication system 1 has decreased (S106), and if the power consumption of the entire wireless communication system 1 has decreased (S106: Yes), the processing ends, and if not (S106: No), the processing proceeds to S108.

[0058] In the process of S108, the central station 4 changes the number of terminals to be charged by energy harvesting, and the process returns to the process of S102.

[0059] In this way, the wireless communication system 1 according to one embodiment controls the efficiency of use of the transmission power of the RF signals transmitted by each base station 3 to each terminal 2 in accordance with parameters calculated by collecting terminal location information, power intensity information, and remaining capacity information of the storage battery 25 for each terminal 2, thereby enabling data transmission via RF signals and energy harvesting to be compatible while optimizing the efficiency of use of power in the entire wireless communication system.

[0060] In addition, each function possessed by the terminal 2, the base station 3, and the central station 4 may be partially or entirely configured by hardware such as a PLD (Programmable Logic Device) or an FPGA (Field Programmable Gate Array), or may be configured as a program executed by a processor such as a CPU.

[0061] For example, the central station 4 can be realized using a computer and a program, and the program can be recorded on a storage medium or provided over a network.

[0062] 6 is a diagram showing an example of the hardware configuration of central station 4 according to one embodiment. As shown in Fig. 6, central station 4 has an input unit 50, an output unit 51, a communication unit 52, a CPU 53, a memory 54, and an HDD 55 connected via a bus 56, and thus functions as a computer. Central station 4 is also configured to input and output data to and from a computer-readable storage medium 57.

[0063] The input unit 50 is, for example, a keyboard and a mouse. The output unit 51 is, for example, a display device. The input unit 50 and the output unit 51 may also be a touch panel or the like.

[0064] The communication unit 52 is, for example, a communication interface that performs wireless communication.

[0065] The CPU 53 controls each component constituting the central station 4 and performs predetermined processing, etc. The memory 54 and HDD 55 store data, etc.

[0066] The storage medium 57 is capable of storing programs and the like that cause the central station 4 to execute the functions of the central station 4. The architecture that constitutes the central station 4 is not limited to the example shown in FIG. [Explanation of symbols]

[0067] 1 Wireless communication system, 2 Terminal, 3 Base station, 4 Central station, 20 Antenna, 21 Switching unit, 22 Information decoder, 23 Power information collection unit, 24 Energy harvester, 25 Storage battery, 26 Remaining power information notification unit, 27 Location information notification unit, 30 Antenna, 31 Information bit generation unit, 32 Modulation and coding unit, 33 Digital-to-analog converter, 34 Wireless conversion unit, 35 Wireless conversion unit, 36 Analog-to-digital converter, 37 Demodulation and decoding unit, 38 Information bit detection unit, 40 Collection unit, 42 Optimization processing unit, 44 Utilization efficiency control unit, 50 Input unit, 51 Output unit, 52... communication unit, 53... CPU, 54... memory, 55... HDD, 56... bus, 57... storage medium, 220... wireless conversion unit, 222... AD conversion unit, 224... demodulation and decoding unit, 226... information bit detection unit, 300... power intensity detection unit, 302... obstacle information detection unit, 304... environmental information detection unit, 390... remaining capacity information acquisition unit, 392... grouping unit, 394... control unit, 402... location information collection unit, 403... remaining capacity information collection unit, 404... power intensity collection unit, 406... obstacle information collection unit, 408... environmental information collection unit, 420... allocated power calculation unit, 422... parameter calculation unit

Claims

1. A wireless communication system includes a central station that centrally controls a plurality of base stations, each capable of accommodating a plurality of terminals, and the plurality of terminals and the base stations perform multi-user MIMO wireless communication, The terminal an information decoder that decodes information that becomes data from the RF signal received from the base station; an energy harvester that charges a storage battery by energy harvesting using an RF signal received from the base station; a switching unit that switches an RF signal received from the base station so as to be supplied to either the information decoder or the energy harvester; and The base station a remaining capacity information acquiring unit that acquires remaining capacity information indicating the remaining capacity of the storage battery of each of the terminals; a grouping unit that groups the plurality of terminals so that they belong to either an information transmission group that transmits information that becomes data or an energy harvesting group that charges a storage battery by energy harvesting, based on the remaining amount information acquired by the remaining amount information acquisition unit and the presence or absence of data to be transmitted to the terminals by RF signals; a control unit that controls band allocation and transmission power of RF signals to be transmitted to each of the terminals for each group grouped by the grouping unit; and The central station a collection unit that collects, via a plurality of the base stations, terminal location information indicating the location of each of the terminals, power strength information indicating the received power strength from each of the terminals, and remaining capacity information of a storage battery of each of the terminals; an allocation power calculation unit that calculates an allocation power for each of the terminals of the base station based on the terminal location information, power strength information, and remaining amount information collected by the collection unit; a parameter calculation unit that calculates parameters that optimize bandwidth allocation and power utilization efficiency for each of the terminals of the base station based on the allocated power calculated by the allocated power calculation unit, so as to minimize power consumption while improving power utilization efficiency of the entire system; and a utilization efficiency control unit that controls utilization efficiency of transmission power of RF signals that each of the base stations transmits to each of the terminals in accordance with the parameters calculated by the parameter calculation unit; A wireless communication system comprising:

2. The parameter calculation unit Calculating parameters that optimize bandwidth allocation and power utilization efficiency for each of the terminals of the base station by changing the number of the terminals belonging to an energy harvesting group so that power consumption of the entire system is minimized.

2. The wireless communication system according to claim 1, wherein:

3. In a central station that centrally controls a plurality of base stations that respectively perform multi-user MIMO wireless communication with a plurality of terminals, a collection unit that collects, via a plurality of the base stations, terminal location information indicating the location of each of the terminals, power intensity information indicating the strength of the received power from each of the terminals, and remaining amount information indicating the remaining amount of power stored in a storage battery of each of the terminals; an allocation power calculation unit that calculates an allocation power for each of the terminals of the base station based on the terminal location information, power strength information, and remaining amount information collected by the collection unit; a parameter calculation unit that calculates parameters that optimize bandwidth allocation and power utilization efficiency for each of the terminals of the base station based on the allocated power calculated by the allocated power calculation unit, so as to minimize power consumption while improving power utilization efficiency of the entire system; and a utilization efficiency control unit that controls utilization efficiency of transmission power of RF signals that each of the base stations transmits to each of the terminals in accordance with the parameters calculated by the parameter calculation unit; 1. A central station comprising:

4. The parameter calculation unit In order to minimize the power consumption of the entire system, the number of terminals belonging to an energy harvesting group that charges a storage battery by energy harvesting without receiving information that becomes data through an RF signal received from the base station is changed, and parameters that optimize bandwidth allocation and power utilization efficiency for each of the terminals of the base station are calculated.

4. A central station according to claim 3, characterized in that:

5. A centralized control method for centrally controlling a plurality of base stations that respectively perform multi-user MIMO wireless communication with a plurality of terminals, comprising: a collection step of collecting, via a plurality of the base stations, terminal location information indicating the location of each of the terminals, power strength information indicating the strength of the received power from each of the terminals, and remaining amount information indicating the remaining amount of power stored in a storage battery of each of the terminals; an allocation power calculation step of calculating an allocation power of the base station to each of the terminals based on the collected terminal location information, power strength information, and remaining capacity information; a parameter calculation step of calculating parameters that optimize bandwidth allocation and power utilization efficiency for each of the terminals of the base station based on the calculated allocated power so as to minimize power consumption while improving power utilization efficiency of the entire system; a utilization efficiency control step of controlling utilization efficiency of transmission power of RF signals transmitted by each of the base stations to each of the terminals in accordance with the calculated parameters; A centralized control method comprising:

6. In the parameter calculation step, In order to minimize the power consumption of the entire system, the number of terminals belonging to an energy harvesting group that charges a storage battery by energy harvesting without receiving information that becomes data through an RF signal received from the base station is changed, and parameters that optimize bandwidth allocation and power utilization efficiency for each of the terminals of the base station are calculated.

6. The centralized control method according to claim 5,

7. 5. A central control program for causing a computer to function as each part of the central station according to claim 3 or 4.

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