Parking space management method and communication device

Abstract

To determine the presence / absence of a parked vehicle in a parking space in a simple configuration.SOLUTION: In a management method for a parking space, a communication device transmits a beam-formed radio signal in a specific direction. In a case where a response signal to the radio signal is received, the communication device determines that a parking space associated with the specific direction is in a vacant state of a vehicle. In a case where no response signal is received, on the other hand, the communication device determines that the parking space is in a parked state.SELECTED DRAWING: Figure 9

Description

[Technical Field]

[0001] The present disclosure relates to a parking space management method and a communication device. [Background technology]

[0002] The following technology has been available in the past (see, for example, Patent Document 1). A transmitter installed in a parking lot transmits transmitter identification information by controlling the on / off of a light-emitting unit. The vehicle device identifies the vehicle device position based on an image captured of the transmitter, calculates a route from the current vehicle device position in map data to a target position, and outputs the calculated route. The vehicle device also notifies the parking lot management device of the vehicle device position. The parking lot management device stores parking lot management information indicating the position and usage status of each parking space, and notifies the vehicle device of the target position, which is the location of a parking space selected from parking spaces with a usage status of vacant. The parking lot management device detects parking in and movement from a parking space based on the vehicle device position received from the vehicle device, and updates the usage status of the parking space. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2020-166459 [Non-patent literature]

[0004] [Non-Patent Document 1] Jonas Ninnemann, Paul Schwarzbach, Oliver Michler, “Multipath-assisted Radio Sensing and Occupancy Detection for Smart In-house Parking in ITS”, January 16, 2022, URL: https: / / arxiv.org / abs / 2201.06128 Summary of the Invention [Problem to be solved by the invention]

[0005] The present disclosure aims to provide a parking space management method and communication device that can determine the presence or absence of a vehicle in a parking space with a simple configuration. [Means for solving the problem]

[0006] One aspect of the present disclosure is a method for managing a parking space, in which a communication device transmits a beamformed radio signal in a specific direction, and if a response signal to the radio signal is received, determines that the state of the parking space associated with the specific direction is vacant, and if a response signal is not received, determines that the state of the parking space is occupied by a vehicle.

[0007] Another aspect of the present disclosure is a communication device that includes a wireless transceiver that transmits a beamformed wireless signal in a specific direction, and a control unit that determines that a parking space associated with the specific direction is vacant when the wireless transceiver receives a response signal to the wireless signal, and determines that the parking space is in a parked state for a vehicle when the wireless transceiver does not receive a response signal.

[0008] Aspects of the present disclosure may include at least one of a computer program for a communication device to perform the above-mentioned parking space management method, a non-transitory storage medium storing the program, or a communication system including the above-mentioned communication device and terminal. [Effects of the Invention]

[0009] According to the present disclosure, it is possible to determine the presence or absence of a vehicle in a parking space with a simple configuration. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a diagram illustrating an example of the configuration of a communication system according to an embodiment. [Figure 2]FIG. 2A is a diagram showing an example of the configuration of an access point (AP), and FIG. 2B is a diagram showing an example of the configuration of a tag. [Figure 3] FIG. 3 is a flowchart showing an example of processing at the time of initial setting of an access point. [Figure 4] FIG. 4 is a diagram illustrating an example of the data structure of a state table generated in an access point. [Figure 5] FIG. 5 is a diagram illustrating an example of a parking space management method. [Figure 6] FIG. 6 is a flowchart showing an example of a state table update process in an access point. [Figure 7] FIG. 7 is a flowchart showing an example of processing in a tag. [Figure 8] FIG. 8A is a diagram showing an updated state of the status table by the processing shown in FIG. 6, and FIG. 8B is a diagram showing an example of the configuration of a terminal. [Figure 9] FIG. 9 is a sequence diagram showing interactions between the access point, each tag, and the terminal mounted on each vehicle. DETAILED DESCRIPTION OF THE INVENTION

[0011] The parking space management method according to the embodiment includes the following. (1) A communication device transmits a beamformed radio signal (radio waves) in a specific direction. (2) When the communication device receives a response signal to the wireless signal, it determines that the state of the parking space associated with a particular direction is vacant, and when it does not receive a response signal, it determines that the state of the parking space is a vehicle parked state.

[0012] Beamforming is a technology that transmits radio waves in a specific direction or receives them from a specific direction. The specific direction can be, for example, one or more directions in which the transmitted radio signal reaches a parking space. This allows the transmission direction of the radio signal to be associated with the status of each parking space. The communication device then determines whether the parking space is vacant or parked based on the presence or absence of a response signal to the radio signal. This makes it possible to determine the presence or absence of a vehicle in a parking space with a simple configuration.

[0013] The wireless signal is preferably a wireless signal in the 28 GHz to 300 GHz band. Radio waves in the 30 GHz to 300 GHz band are generally called millimeter waves. In 5G (fifth generation mobile communication system), the 28 GHz band is also considered a "millimeter wave." Millimeter waves are suitable for high-speed communication. However, because millimeter waves have a strong tendency to travel in a straight line, they tend to be vulnerable to obstructions. For this reason, for example, if a specific direction (the transmission direction of the wireless signal) is set to reach each parking space, the beamformed wireless signal will reach the desired parking space and will not reach other parking spaces. This allows each parking space to be uniquely associated with the transmission direction of the wireless signal.

[0014] For example, a terminal (communication device) is provided for each parking space, which receives a wireless signal and returns a response signal to the communication device. The terminal is arranged or installed so that it is shielded when a vehicle is parked in the parking space, preventing reception of the wireless signal. When the vehicle is parked, the response signal is not returned to the communication device (the response signal cannot be received). Therefore, the communication device can determine whether a vehicle is present in the parking space, i.e., whether the parking space is parked or vacant, based on the presence or absence of a response signal from the terminal. In this way, the status of the parking space can be determined with a simple configuration.

[0015] The frequency band applied to the wireless signal may be other than the frequency band (28 GHz band to 300 GHz band) treated as millimeter waves. Furthermore, the configuration for blocking the wireless signal may be a configuration in which a blocking object blocks the terminal, thereby inhibiting reception of the wireless signal by the terminal. The blocking object may be located within the parking space or outside the parking space. The blocking object may be a vehicle or something other than a vehicle. For example, the blocking object may be a vehicle parked in the parking space. That is, the body of the parked vehicle may block the terminal, thereby inhibiting reception of the wireless signal by the terminal. Furthermore, the configuration for blocking the wireless signal may be a blocking object other than a vehicle, such as a structure installed in the parking space, which deforms or changes its position as the vehicle is parked, thereby blocking the terminal, thereby inhibiting reception of the wireless signal. The structure and the terminal do not necessarily need to be installed in the parking space, as long as parking in the parking space inhibits reception of the wireless signal by the terminal or transmission of a response signal. Thus, the specific direction may be a direction other than the direction toward the parking space. The deformation or change of position of the structure can be performed depending on the presence or absence of a parked vehicle in the parking space, which can be detected by a sensor and controlled by a control device.

[0016] The response signal is preferably a radio signal that is beamformed so as to be transmitted in a specific direction toward the location of the communication device. By receiving radio waves arriving from a specific direction, the communication device can accurately receive the desired response signal. However, beamforming of the response signal is not essential as long as the response signal can be received by the communication device.

[0017] For example, receiving a response signal may include receiving a response signal transmitted by a terminal that received a wireless signal in an empty parking space, and not receiving a response signal may include not receiving a response signal from a terminal that transmitted the response signal due to blocking by an obstruction.

[0018] The information indicating the status of the parking space obtained by the above-mentioned determination can be used to update the information indicating the status of the parking space that is stored in association with the transmission direction of the wireless signal. The communication device can also transmit beamformed wireless signals in each of a plurality of transmission directions, and store information indicating the status of each parking space in association with each transmission direction when a response signal to the wireless signal is returned.

[0019] The management method may include the communication device outputting information indicating the status of the parking space based on the above-mentioned determination. The output may include the communication device displaying or outputting the information indicating the status as sound. The output may also include transmitting the information indicating the status of the parking space using a radio signal in a second frequency band different from the first frequency band used for transmitting the radio signal. The output of the information indicating the status of the parking space may also be performed by broadcast transmission. However, the output of the information may also be transmitted to the information destination by unicast. The output of the information may also include transmitting a radio signal directed to the vehicle desiring to park. This allows the user of the vehicle desiring to park to be notified of the status of the parking space.

[0020] Hereinafter, a parking space management method and a communication device according to an embodiment will be described with reference to the drawings. The configurations of the embodiments are merely examples, and the present invention is not limited to the configurations of the embodiments.

[0021] <Communication system configuration> FIG. 1 shows an example of a communication system according to an embodiment. In FIG. 1, a parking lot (parking area) 10 has parking spaces 11 for vehicles 12. In the example shown in FIG. 1, the parking lot 10 has six parking spaces 11a to 11f. However, the number of parking spaces 11 may be one or two or more, and any appropriate number can be adopted. The vehicles 12 may be either human-operated vehicles or autonomous vehicles.

[0022] Parking spaces 11a to 11f are equipped with a wireless LAN (Wi-Fi) access point (A The coverage area of ​​the wireless signal transmitted from AP2 (radio waves emitted from AP2) covers parking spaces 11a to 11f.

[0023] Each of the parking spaces 11a to 11f is provided with a tag 3 (3a to 3f) that receives a wireless signal from the AP 2 and transmits a response signal to the AP 2. The AP 2 can detect the tag 3 by transmitting a wireless signal to the tag 3 and receiving a response signal from the tag 3.

[0024] The AP2 performs beamforming on the radio signals to be transmitted to the tags 3, and can transmit the radio signals in the direction that reaches each of the tags 3a to 3f (an example of a "specific direction"). The specific direction associated with the tags 3a to 3f is called a "transmission sector." The tags 3a to 3f can also perform beamforming on the response signals, and transmit radio waves of the response signals in the direction where the AP2 is located. The transmission direction of the response signals is called a "response sector."

[0025] In this embodiment, the AP 2 uses a radio signal in the 28 GHz band (millimeter wave) to detect the tag 3. However, as long as the radio signal can be transmitted in a specific direction by beamforming, microwaves (such as quasi-millimeter waves) other than the frequency band treated as millimeter waves may also be used.

[0026] Each of the tags 3a to 3f is placed or installed in a durable and weather-resistant state approximately in the center of the corresponding parking space 11a to 11f. When the vehicle 12 is parked, each of the tags 3a to 3f is covered and shielded by the body of the vehicle 12. However, the placement position and installation method of the tag 3 need only be configured so that when the vehicle 12 is parked in the parking space 11, the tag 3a to 3f is shielded by the parked vehicle 12 or a structure other than the vehicle 12.

[0027] The AP 2 is a wireless communication device capable of communicating with the tag 3 and the terminal 4, and is an example of a "communication device." The tag 3 is also an example of a "terminal" that transmits a response signal. The AP 2 can also be called a parent device, and the tag 3 can also be called a child device. In this embodiment, an example is shown in which communication between the communication device and the terminal is performed via wireless LAN (IEEE802.11 series, including Wi-Fi). However, as long as the transmission direction of a wireless signal can be controlled by beamforming, a wireless communication standard other than wireless LAN may be applied.

[0028] The AP2 can determine whether or not a vehicle 12 is parked in the parking space 11 corresponding to the tag 3, i.e., the state (parked state or vacant state) of the parking space 11, based on the presence or absence of a response signal from the tag 3. The AP2 can output information indicating the state of the parking space 11 obtained by the determination (referred to as "state information").

[0029] In this embodiment, the AP 2 can broadcast status information to vehicles 12 present within the coverage area of ​​the AP 2. The vehicle 12 is equipped with a terminal 4, which can receive the broadcast status information. The terminal 4 can notify a passenger (driver or passenger) of the vehicle 12 of the status information by voice, image, flashing light, or the like, and the passenger can recognize vacant parking spaces 11 from the status information. The AP 2 can use a frequency band (e.g., Sub6, e.g., 2.4 / 5 GHz band) different from millimeter waves (e.g., 28 GHz band) to communicate with the terminal 4. A frequency band treated as millimeter waves is an example of a "first frequency band," and the 2.5 / 5 GHz band is an example of a "second frequency band."

[0030] The terminal 4 may be a terminal fixed to the vehicle 12 (stationary type), or a portable terminal held by a passenger (a mobile terminal such as a smart device such as a smartphone). The status information may be transmitted to a vehicle 12 (terminal 4) located outside the coverage area of ​​the AP 2 via a network.

[0031] <Configuration Examples of AP and Tags> FIG. 2A is a diagram showing a configuration example of AP2, and FIG. 2B is a diagram showing a configuration example of a tag. AP2 includes a processor 21 as a processing unit or a control unit (controller) interconnected via a bus 26, a storage device 22, and a communication interface 23 (communication IF23). Further, AP2 may include an input device 24 and a display 25.

[0032] The storage device 22 includes a main storage device and an auxiliary storage device. The main storage device is used as at least one of a storage area for programs and data, a deployment area for programs, a working area for programs, and a buffer area for communication data. The main storage device is composed of a RAM (Random Access Memory), or a combination of a RAM and a ROM (Read Only Memory). The auxiliary storage device is used as a storage area for data and programs. A non-volatile storage medium is applied to the auxiliary storage device. The non-volatile storage medium is, for example, a hard disk, a Solid State Drive (SSD), a flash memory, or an EEPROM (Electrically Erasable Programmable Read-Only Memory). Further, the storage device 22 may include a drive device for a disk recording medium. [[ID=IO]]

[0033] The communication IF23 is a circuit that performs communication processing. The communication IF23 includes a wireless transceiver and an array antenna 23a for transmitting and receiving a wireless signal for detecting tag 3 and a response signal, and a wireless signal for communication with the terminal 4. The array antenna 23a can be adapted to concentrate the radiation of radio waves in a specific direction (directional) under the control of the processor 21, for example. That is, a wireless signal can be transmitted in a specific direction by beamforming using the array antenna 23a. Further, the communication IF23 may include a wireless communication circuit that performs wireless communication with a network (another AP or a base station of a cellular network).

[0034] The input device 24 includes keys, buttons, a pointing device, a touch panel, etc., and is used to input information. The display 25 is, for example, a liquid crystal display, etc., and displays information and data.

[0035] The processor 21 performs various processes by executing various programs stored in the storage device 22. For example, the processor 21 performs a process (initial setting) to identify the direction in which the tags 3a to 3f (parking spaces 11a to 11f) are located. The processor 21 also performs a process to determine whether or not a vehicle 12 is present in each of the parking spaces 11a to 11f. The processor 21 also performs a process to transmit the status (status information) of each of the parking spaces 11a to 11f to the vehicle 12.

[0036] FIG. 2B is a diagram showing an example configuration of the tag 3. The tag 3 includes a processor 31, a storage device 32, a wireless transceiver 33, and an array antenna 33a, which are interconnected via a bus 36. The processor 31, the storage device 32, the wireless transceiver 33, and the array antenna 33a can be similar to the wireless transceiver and the array antenna 23a included in the processor 21, the storage device 22, and the communication IF 23. Therefore, a description of these components will be omitted. The processor 31 performs beamforming using the array antenna 33a so that a response signal is transmitted in the direction (specific direction) where the AP 2 is located. However, beamforming is not essential if the AP 2 can receive the response signal.

[0037] <Initial settings> FIG. 3 is a flowchart showing an example of processing performed during initial setup of an access point. can transmit wireless signals in multiple directions (transmission sectors) by beamforming. In the initial setting, the direction in which the tag 3 (parking space 11) is located is detected from the multiple directions. In the process of FIG. 3, k is the number of the transmission sector, and N is the number of transmission sectors used in the initial setting. The process shown in FIG. 3 is performed by the processor 21 of the AP 2 executing a program stored in the storage device 22. The initial setting is performed when all of the parking spaces 11 to be managed (for example, parking spaces 11a to 11f) are vacant, such as when the parking lot 10 is closed.

[0038] In step S01, the processor 21 controls the array antenna 23a by beamforming. Through this control, a state is set in which a radio signal is transmitted in a specific direction corresponding to the current transmission sector k. The processor 21 transmits a trigger frame using the radio transceiver of the communication IF 23 and the array antenna 23a. The trigger frame is a radio frame (radio signal) for detecting the tag 3. The processor 21 sets a timer that counts a predetermined time when the trigger frame is transmitted. The length of the timer can be set as appropriate.

[0039] In step S02, processor 21 determines whether the timer has expired. If it is determined that the timer has expired, the process proceeds to step S05; otherwise, the process proceeds to step S03.

[0040] In step S03, the processor 21 receives a response signal (acknowledgement: It is determined whether a response signal (ACK) has been received by the array antenna 23a and the wireless receiver. If it is determined that a response signal has been received, the process proceeds to step S04; if not, the process returns to step S02.

[0041] In step S04, the processor 21 generates a record and registers it in the status table (FIG. 4). The record includes the transmitting sector k that transmitted the wireless signal, the identifier of the tag 3 included in the response signal, the transmitting sector (response sector) indicating the transmission direction of the response signal, and information indicating the status of the parking space 11.

[0042] In step S05, processor 21 determines whether the value of the number k of the current transmitting sector is less than the number N of transmitting sectors. If it is determined that the value of k is less than N, processor 21 increments the value of k (step S06) and returns the process to step S01. If it is determined that the value of k is equal to or greater than N, the process ends.

[0043] 3, information relating to the transmission sector in which the tag 3 (parking space 11) is present among the multiple transmission sectors is registered in the status table. The status table is stored in the storage device 22. However, the status table may be stored (saved) in a location other than the storage device 22.

[0044] <Status table> FIG. 4 is a diagram showing an example of the data structure of a status table generated in an access point. The status table consists of multiple records (entries). Each record includes information indicating the sender, transmitting sector, corresponding tag, responding sector, and whether or not there is a parked vehicle. The sender is identification information of the AP 2 (for example, SSID), but an identifier other than SSID may be used. The transmitting sector is information indicating the transmitting direction of the wireless signal (trigger frame). The corresponding tag is the identifier of the tag 3 that returned the response signal. The responding sector is information indicating the transmitting sector (transmitting direction) used by the tag 3 when transmitting a response signal to the AP 2, and is the direction in which the AP 2 is located. The information indicating the parked vehicle is information indicating whether or not there is a vehicle 12 in the parking space 11, i.e., whether the parking space 11 is parked or vacant. This information can be managed, for example, using a binary flag (for example, vacant: "0", parked: "1", or vice versa). can.

[0045] In the example shown in FIG. 1, the state table has records registered therein indicating the transmitting sector, corresponding tag, responding sector, and whether or not there is a parked vehicle, corresponding to tags 3a to 3f. The above-mentioned initial setting (state table in the initial state) is, for example, a beamforming state of IEEE 802.11ad. It can be created using a learning training method.

[0046] <Parking space management method> FIG. 5 is a diagram illustrating an example of a parking space management method. FIG. 5 shows an example of the usage state of the parking lot 10 shown in FIG. 1. Of the parking spaces 11a to 11f, parking spaces 1a, 11c, 11d, and 11e are occupied by vehicles 12. Parking spaces 11b and 11f are vacant. Tags 3a, 3c, 3d, and 3e of parking spaces 1a, 11c, 11d, and 11e are blocked by the vehicle 12 and cannot receive wireless signals from AP2. In other words, AP2 can receive response signals from tags 3b and 3f. Vehicles 12a and 12b are vehicles that wish to use the parking lot 10 (enter parking space 11), and each of vehicles 12a and 12b is equipped with a terminal 4 (4a, 4b, and 4c).

[0047] FIG. 6 is a flowchart showing an example of a status table update process in AP 2. The process shown in FIG. 6 is executed by processor 21 periodically or periodically. Processor 21 determines whether or not there is a parked vehicle for each record registered in the status table. The records in the status table are referenced in a predetermined order. In this embodiment, the records are arranged in numerical order of transmission sector k (k=0, 1, . . . , k-1, k), and processing is performed in ascending order of k values. However, the order in which each record is processed is arbitrary.

[0048] In step S101, the processor 21 refers to the record pointed to by the pointer in the state table. In the first step S101, the pointer points to the record corresponding to the smallest k value. The processor 21 transmits a trigger frame to the transmission sector k in the record and sets a timer. The processor 21 includes in the trigger frame the identifier of the tag 3 included in the record.

[0049] The processing in steps S02 and S03 is the same as in Fig. 3, and therefore description thereof will be omitted. If a response signal (ACK) is received from the tag 3 before the timer expires, or if the timer expires, the processing proceeds to step S104.

[0050] In step S104, processor 21 updates the information indicating the presence or absence of a parked vehicle (the state of parking space 11) in the corresponding record (the record being referenced). If the process proceeds to step S104 based on the reception determination of the response signal, processor 21 records information indicating "vehicle present" as the information indicating the presence or absence of a parked vehicle (sets the flag indicating the parking state to "1").

[0051] On the other hand, if the process proceeds to step S104 due to the timer expiration determination, processor 21 records information indicating "no vehicle" as information indicating whether or not there is a parked vehicle (sets the flag "0" (which may be NULL) indicating an empty state).

[0052] In step S105, processor 21 determines whether the value of the current transmission sector number k is less than the number n of transmission sectors registered in the state table. If it is determined that the value of k is less than n, processor 21 increments the value of k (step S06) and returns the process to step S101. At this time, the pointer in the state table points to the record corresponding to k+1, and the processes from step S101 onwards are performed for the next record. If it is determined in step S105 that the value of k is equal to or greater than n, the process ends.

[0053] 7 is a flowchart showing an example of processing in the tag 3. The processing shown in FIG.

[0054] In step S11, the processor 31 of the tag 3 detects the AP 2 by periodically or periodically transmitting a radio signal to detect the AP 2 in a response sector and receiving a response (ACK) from the AP 2. While performing this detection process for the AP 2, the tag 3 waits for a trigger frame from the AP 2.

[0055] In step S12, the processor 31 determines whether or not a trigger frame has been received from the AP 2. If it is determined that a trigger frame has been received, the process proceeds to step S03; otherwise, the process returns to step S11.

[0056] In step S13, the processor 31 determines whether the trigger frame is addressed to the own tag. That is, the processor 31 determines whether the identifier of the tag 3 included in the trigger frame is the identifier of the own tag. If it is determined that the identifier of the tag 3 is the identifier of the own tag, the process proceeds to step S14; if not, the process returns to step S11.

[0057] In step S14, the processor 31 transmits a response signal (ACK) to the trigger frame in the response sector. The response signal is received by the AP 2. After step S14 ends, the process returns to step S11.

[0058] Figure 8A is a diagram showing the updated state of the status table after the processing shown in Figures 6 and 7. The statuses of parking spaces 11b and 11f corresponding to tags 3b and 3f are updated to vacant, and the statuses of the remaining parking spaces 11a, 11c, 11d, and 11e are set to parked.

[0059] FIG. 9 is a sequence diagram showing the exchanges between the AP 2, each tag 3, and the terminal 4 mounted on each vehicle 12. The AP 2 performs the process shown in FIG. 6 and transmits a trigger frame to each transmission sector registered in the status table (FIG. 9). <1> ) If each tag 3 receives the trigger frame, it sends a response signal (ACK) to the AP 2 (Fig. 9<2a>). However, if the trigger frame does not reach the tag 3 and is not received, the tag 3 does not send an ACK (Fig. 9<2b>).

[0060] AP2 determines the status of the parking space 11 corresponding to the transmission sector based on whether or not an ACK is received before the timer expires, and updates the status table with the status obtained by the determination (see FIG. 9). <3> , see Figure 6).

[0061] The processor of AP2 generates a wireless signal (beacon frame informing the parking situation) including information indicating the status of the parking spaces 11a to 11f in the updated status table (FIG. 9 <4> ) The beacon frame is broadcast so that it can be received by all vehicles 12 (terminals 4) within the reach of the beacon frame. In other words, the beacon frame informing the parking situation is transmitted by broadcast (see FIG. 9). <5> ) By broadcasting, the terminal 4 can receive the parking status (information indicating vacant parking spaces 11) without a separate handshake with the AP 2.

[0062] The beacon frame is transmitted using a frequency band (for example, 2.4 / 5 GHz band) different from the 28 GHz band used to detect the tag 3. This is because this frequency band is a standard frequency band used by 5G, and therefore can easily communicate with 5G-compatible smart devices.

[0063] The beacon frames are received by a terminal 4 mounted on each of the vehicles 12a and 12b. As shown in FIG. 8B, the terminal 4 includes a processor 41, a storage device 42, and a communication interface 43 (communication IF 43), which are interconnected via a bus 46. The terminal 4 may also include an input device 44 and a display 45.

[0064] The processor 41, the storage device 42, the communication IF 43, the input device 44, and the display 45 may be the same as the processor 21, the storage device 22, the communication IF 23, the input device 24, and the display 25.

[0065] The terminal 4 receives the beacon frame using the communication IF 43. Then, the processor 41 performs processing to display the information indicating the parking situation contained in the beacon frame (information indicating the vacant parking spaces 11 or information indicating the status of each of the parking spaces 11a to 11f) on the display 45. The terminal 4 may further have a speaker, and audio indicating the parking situation may be output from the speaker. Either display of information or audio output may be performed, or both may be performed. In this way, the information indicating the parking situation is notified to the passengers of the vehicle 12 (see FIG. 9 <6> ).

[0066] The processors 21, 31, and 41 are, for example, a Central Processing Unit (CPU). A CPU is also called a Microprocessor Unit (MPU). The processor may have a single processor configuration or a multi-processor configuration. Also, a single physical CPU connected via a single socket may have a multi-core configuration. The processor may be a Digital Signal Processor (DSP) or a Graphics Processing Unit (GP). The processor may include various circuit configurations of arithmetic units, such as an integrated circuit (IC), other digital circuitry, and / or analog circuitry. The integrated circuit may include an LSI, an Application Specific Integrated Circuit (ASIC), a programmable logic device (PLD), etc. A PLD may include, for example, For example, the processors 21 and 41 include a Field-Programmable Gate Array (FPGA). For example, it includes what are called microcontrollers (MCUs), SoCs (System-on-a-chips), system LSIs, chipsets, etc.

[0067] <Effects of the embodiment> In the embodiment, a communication device (AP2) transmits a beamformed wireless signal (trigger frame) in a specific direction. Furthermore, when the AP2 receives a response signal (ACK) to the trigger frame (when the tag 3 is detected), the AP2 determines that the state of the parking space associated with the specific direction is vacant. In contrast, when the AP2 does not receive an ACK (when the tag 3 is not detected), the AP2 determines that the state of the parking space is a parked state for the vehicle 12. In this way, the state (vacant state or parked state) of the parking space associated with the specific direction can be determined with a simple configuration, such as determining whether or not there is a response signal in the specific direction.

[0068] In this embodiment, a frequency band from 28 GHz to 300 GHz (a frequency band treated as millimeter waves) is used to transmit the trigger frame. Millimeter waves have a strong tendency to travel in a straight line and are vulnerable to obstruction, so beamforming can be used to prevent one trigger frame from being received by multiple tags 3, and the direction of transmission of the trigger frame can uniquely associate the parking space 11 (tag 3).

[0069] The AP2 can determine whether the parking space 11 is vacant by receiving a response signal (ACK) transmitted by the tag 3 (terminal) that received the trigger frame in the vacant parking space 11. On the other hand, the AP2 can determine the parking status of the parking space 11 when the tag 3 is blocked by the vehicle 12 parked in the parking space 11 and the AP2 does not receive the ACK.

[0070] In the embodiment, the AP2 can update the information indicating the status of the parking space, which is stored in association with the transmission direction (transmission sector) of the trigger frame, to the status of the parking space obtained by the determination, thereby obtaining the latest status of the parking space.

[0071] In the embodiment, the AP2 initially transmits a beamformed wireless signal (trigger frame) in each of a plurality of transmission directions. The AP2 also stores information in a status table (storage device 22) indicating a correspondence between a transmission direction when an ACK is returned for the trigger frame and the state of the parking space 11. This allows the AP2 to learn and store a transmission sector associated with the state of the parking space.

[0072] The AP 2 can output information indicating the state (vacant state or parked state) of the parking space 11 based on the above-mentioned determination. In the embodiment, as an example of output, the wireless transceiver of the AP 2 transmits a wireless signal (beacon frame) including information indicating the state (parking status) of the parking space 11 based on the determination.

[0073] The beacon frame can be transmitted using a second frequency band (e.g., Sub6) different from the frequency band (first frequency band) used as millimeter waves. The beacon frame can be transmitted by broadcast. However, unicast transmission is also possible. The beacon frame is transmitted to a vehicle 12 that wishes to park in the parking lot 10. However, information indicating the status of the parking space 11 may be transmitted to a predetermined communication partner via a network.

[0074] The above-described embodiment and modifications are merely examples, and the present disclosure may be modified as appropriate within the scope of the gist thereof. Furthermore, the processes and means described in the present disclosure may be freely combined and implemented as long as no technical contradiction occurs.

[0075] Furthermore, a process described as being performed by one device may be shared and executed by multiple devices. Alternatively, a process described as being performed by different devices may be executed by one device. In a computer system, the hardware configuration (server configuration) that realizes each function can be flexibly changed. For example, multiple devices may be connected via a network and function as the above-mentioned AP2.

[0076] The present disclosure can also be realized by supplying a computer program that implements the functions described in the above embodiments to a computer, and having one or more processors of the computer read and execute the program. Such a computer program may be provided to the computer by a non-transitory computer-readable storage medium connectable to the system bus of the computer, or may be provided to the computer via a network. Non-transitory computer-readable storage media include any type of disk, such as a magnetic disk (e.g., a floppy disk, a hard disk drive (HDD), etc.) or an optical disk (e.g., a CD-ROM, a DVD disk, a Blu-ray disk, etc.). In addition, non-transitory computer-readable media (non-transitory storage media) may be any suitable medium for storing electronic instructions. Non-transitory storage media include read-only memory (ROM), random-access memory (RAM), EPROM, EEPROM, magnetic cards, flash memory, and optical cards. [Explanation of symbols]

[0077] 2. Access point, 3. Tag, 4. Terminal, 21, 31, 41. Processor, 22, 32, 42. Storage device, 23. Communication interface (wireless transceiver)

Claims

1. The communication device Transmitting a beamformed radio signal in a specific direction; determining that the state of the parking space associated with the specific direction is vacant when a response signal to the wireless signal is received, and determining that the state of the parking space is a vehicle parked state when the response signal is not received; A parking space management method that implements

2. The transmission of the radio signal includes transmission of a radio signal in a band from 28 GHz to 300 GHz. The parking space management method according to claim 1.

3. Receiving the response signal includes receiving the response signal transmitted by a terminal that received the wireless signal in the vacant parking space. The parking space management method according to claim 1.

4. The non-reception of the response signal includes a case where a terminal transmitting a response signal to the wireless signal is blocked by a shield, and the communication device does not receive the response signal within a predetermined time from the transmission of the wireless signal. The parking space management method according to claim 1.

5. The method further includes updating, by the communication device, information indicating the state of the parking space, which is stored in association with the transmission direction of the wireless signal, to the state of the parking space obtained by the determination. The parking space management method according to claim 1.

6. The communication device Transmitting beamformed radio signals in each of a plurality of transmission directions; Among the plurality of transmission directions, a transmission direction when a response signal to the wireless signal is returned is stored in association with the state of the parking space. The method for managing parking spaces according to claim 5, further comprising:

7. The communication device further includes outputting information indicating a state of the parking space based on the determination. The parking space management method according to claim 1.

8. The output includes transmitting information indicating the status of the parking space using a radio signal in a second frequency band different from a first frequency band used for transmitting the radio signal. The parking space management method according to claim 7.

9. The output of the information indicating the status of the parking space includes transmission by broadcast. The parking space management method according to claim 7.

10. The output includes transmitting information indicating the status of the parking space to a vehicle desiring to park. The parking space management method according to claim 7.

11. a radio transceiver that transmits a beamformed radio signal in a specific direction; When the wireless transceiver receives a response signal to the wireless signal, it determines that the parking space associated with the specific direction is vacant, and when it does not receive the response signal, it determines that the parking space associated with the specific direction is vacant. a control unit that determines that the state of the parking space is a vehicle parked state when A communication device comprising:

12. The radio signal is a radio signal in the 28 GHz to 300 GHz band. The communication device according to claim 11.

13. The wireless transceiver receives the response signal transmitted by a terminal that has received the wireless signal in the vacant parking space. The communication device according to claim 11.

14. The control unit determines whether the wireless transceiver receives the response signal within a predetermined time from the transmission of the wireless signal. The communication device according to claim 11.

15. When the determination is made, the control unit updates information indicating the state of the parking space, which is stored in association with the transmission direction of the wireless signal, to the state of the parking space obtained by the determination. The communication device according to claim 11.

16. the wireless transceiver transmits beamformed wireless signals in each of a plurality of transmission directions; The control unit stores, among the plurality of transmission directions, a transmission direction when a response signal to the wireless signal is returned, in association with information indicating a state of the parking space.

16. The communication device of claim 15.

17. The control unit outputs information indicating the state of the parking space based on the determination. The communication device according to claim 11.

18. The wireless transceiver transmits information indicating the status of the parking space using a wireless signal in a second frequency band different from a first frequency band used for transmitting the wireless signal.

18. The communication device of claim 17.

19. The wireless transceiver broadcasts information indicating the status of the parking space.

18. The communication device of claim 17.

20. The wireless transceiver transmits information indicating the status of the parking space to a vehicle that desires to park.

18. The communication device of claim 17.

Images