Communication connection management system, communication connection management method, and computer

Abstract

This communication connection management system is provided with a BLE module (2) for wireless communication with a portable device (9). In the wireless communication with the portable device (9) via the BLE module (2), priority information for determining whether or not the portable device (9) should be prioritized for a communication connection over other portable devices is acquired from the portable device (9). When determining, during communication connections with a plurality of portable devices (9), the number of which is equal to a connection upper limit number, that communication connections of new portable devices (9) should be prioritized on the basis of the priority information, the communication connection management system disconnects the communication connections with any of the portable devices (9) being connected, the number of which is equal to the connection upper limit number, and establishes the communication connections with the new portable devices (9).

Description

Communication connection management system, communication connection management method, and computer CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is based on Patent Application No. 2023-210528 filed in Japan on December 13, 2023, and the contents of the original application are incorporated by reference in their entirety.

[0002] The present disclosure relates to techniques for managing communication connections between an object and multiple mobile devices.

[0003] Patent Literature 1 discloses a system that can prioritize connection of mobile terminals of users who are estimated to need connection more even when the number of mobile terminals simultaneously connected to the same vehicle is smaller than the number of vehicle users. The system in Patent Literature 1 determines the priority order of each user's mobile terminal based on the mobile terminal's location and whether or not vehicle control request-related information has been received. Specifically, the mobile terminal that has received vehicle control request-related information is given the highest priority, and the priority of each mobile terminal is determined in descending order from the closest to the furthest location. When the system in Patent Literature 1 needs to establish simultaneous communication connections with more than a specified number of mobile terminals, it selects a mobile terminal to disconnect from the communication connection based on the determined priority order.

[0004] Japanese Patent Application Laid-Open No. 2021-136457

[0005] However, the system of Patent Document 1 does not take into consideration the identity of the mobile terminal when selecting a mobile terminal to connect to for communication. For example, if the mobile terminal is an owner terminal held by the vehicle owner, it is desirable to prioritize the mobile terminal for connecting to the vehicle over other mobile terminals to ensure the convenience of the owner. Also, if the mobile terminal is a friend terminal held by a user (such as a family member or friend, a service provider, or a valet parking attendant) who has been authorized by the owner to access or use the vehicle, when the friend terminal approaches the vehicle, it is preferable to prioritize the friend terminal for connecting to the vehicle over other mobile terminals because the user is likely to access or use the vehicle.

[0006] The present disclosure has been made in consideration of the above-mentioned points, and aims to provide a communication connection management system, a communication connection management method, and a computer that can easily ensure a communication connection with an object for a mobile device that should be given priority over other mobile devices in a communication connection with the object.

[0007] In order to achieve the above object, the communication connection management system according to the present disclosure is a communication connection management system that manages communication connections between an object and a plurality of portable devices, and is configured to include: a communication unit that is provided in the object and performs wireless communication with the portable devices; the communication unit has a set upper limit on the number of portable devices that can establish a communication connection; an acquisition unit that, when a portable device is a portable device that should be given priority for communication connection, acquires priority information from the portable device by wireless communication with the portable device via the communication unit, indicating that the portable device is a portable device that should be given priority for communication connection; and a communication connection control unit that, when a communication connection with the plurality of portable devices up to the upper limit is in progress and the acquisition unit acquires the priority information by communication with a new portable device, disconnects the communication connection with one of the portable devices among the upper limit of the number of portable devices that are currently being connected for communication, and establishes a communication connection with the new portable device.

[0008] Furthermore, the communication connection management method according to the present disclosure is a computer-executed communication connection management method for managing communication connections between an object and a plurality of portable devices, wherein the object has a communication unit that wirelessly communicates with the portable devices, the communication unit has a set upper limit on the number of portable devices that can establish a communication connection, and when a portable device is a portable device that should be given priority for communication connection, priority information indicating that the portable device is a portable device that should be given priority for communication connection is obtained from the portable device by wireless communication with the portable device via the communication unit, and when priority information is obtained by communication with a new portable device while a communication connection with the maximum number of portable devices is in progress, the communication connection with one of the portable devices that is currently in progress for communication and the communication connection with the new portable device is disconnected, and a communication connection with the new portable device is established.

[0009] Furthermore, a computer according to the present disclosure is a computer that executes a process for managing communication connections between an object and a plurality of portable devices, wherein the object has a communication unit that performs wireless communication with the portable devices, and the communication unit has a set upper limit number of connections for the portable devices that can establish communication connections, and the computer is configured to execute the following processes: if the portable device is a portable device that should be given priority for communication connection, acquire priority information from the portable device, by wireless communication with the portable device via the communication unit, indicating that the portable device is a portable device that should be given priority for communication connection; and if the computer acquires priority information by communication with a new portable device while it is currently communicating with the maximum number of portable devices, terminate the communication connection with one of the portable devices that is currently communicating with the maximum number of portable devices, and establish a communication connection with the new portable device.

[0010] According to the communication connection management system, communication connection management method, and computer disclosed herein, as described above, when a portable device is a portable device that should be prioritized for communication connection, priority information indicating that the portable device is a portable device that should be prioritized for communication connection is acquired from the portable device through wireless communication with the portable device via a communication unit. Then, when the priority information is acquired through communication with a new portable device while a communication connection with the upper limit number of portable devices is in progress, the communication connection with one of the currently connected portable devices is terminated, and a communication connection with the new portable device is established. As a result, it is possible to easily secure a communication connection with an object for a portable device that has reason to be prioritized over other portable devices, i.e., for which priority information has been acquired.

[0011] The reference numbers in parentheses in this section and in the claims merely indicate an example of the correspondence with specific configurations in the embodiments described below, in order to facilitate understanding of the present disclosure, and are not intended to limit the scope of the present disclosure in any way.

[0012] Furthermore, the technical features of the present disclosure other than those described above will become apparent from the following description of the embodiments and the accompanying drawings.

[0013] 1 is a diagram showing an overall view of a vehicle electronic key system to which a communication connection management system is applied. FIG. 2 is a block diagram showing the configuration of a portable device. FIG. 3 is a block diagram showing the configuration of an in-vehicle system. FIG. 4 is a diagram showing an example of the placement of a BLE module in a vehicle. FIG. 5 is a block diagram showing the configuration of the BLE module. FIG. 6 is a diagram showing an outline of the flow of a CS ranging process. FIG. 7 is a diagram for explaining the operation of a portable device and an in-vehicle system when the portable device and the in-vehicle system are not yet connected for communication. FIG. 8 is a diagram for explaining the operation of a portable device and an in-vehicle system when the portable device and the in-vehicle system periodically perform data communication via BLE communication after a communication connection between the portable device and the in-vehicle system is established. FIG. 9 is a diagram for explaining the operation of a portable device and an in-vehicle system when the portable device and the in-vehicle system perform CS ranging communication. FIG. 10 is a functional block diagram of a main controller. FIG. 11 is a diagram showing an example of areas set inside and outside a vehicle in order to determine the location of a device based on whether it belongs to an area. FIG. 12 is a flowchart showing an example of a communication connection management process for limiting the number of portable devices that can be connected for communication at the same time to a predetermined upper connection limit. FIG. 13 is a diagram showing an example of classifying portable devices to be connected for communication based on the area in which the portable device is located and whether or not a digital key app is running. FIG. 13 is a diagram showing several examples for determining the priority order between a mobile device currently connected for communication and a mobile device that has accepted a connection request and newly established a communication connection. FIG. 14 is an explanatory diagram for explaining an example of operation by the processing shown in the flowchart of FIG. 12. FIG. 15 is a flowchart showing an example of communication connection management processing according to a second embodiment, which limits the number of mobile devices that connect for communication at the same time to a predetermined upper limit number of connections. FIG. 16 is an explanatory diagram showing an example of operation by the processing shown in the flowchart of FIG. 16. FIG. 17 is a flowchart showing an example of communication connection management processing according to a third embodiment, which limits the number of mobile devices that connect for communication at the same time to a predetermined upper limit number of connections. FIG. 18 is an explanatory diagram for explaining an example of operation by the processing shown in the flowchart of FIG. 18. FIG. 19 is a block diagram showing the configuration of a mobile device according to a fourth embodiment. FIG. 20 is a block diagram showing the configuration of an in-vehicle system according to a fourth embodiment. FIG. 21 is a diagram showing an example of arrangement of a BLE module and a UWB module in a vehicle according to a fourth embodiment.10 is a diagram for explaining the operation of the portable device and the in-vehicle system when the portable device and the in-vehicle system perform UWB ranging communication.

[0014] The following describes, with reference to the drawings, an embodiment in which a communication connection management system, a communication connection management method, and a computer according to the present disclosure are applied to a vehicle electronic key system. That is, in this embodiment, the number of communication connections of a portable device 9 used as an electronic key in a vehicle electronic key system is limited to an upper limit while prioritizing communication connections with portable devices 9 from which priority information has been acquired. However, the present disclosure is not limited to the following embodiment, and various modifications described below are also within the technical scope of the present disclosure. Furthermore, various modifications other than those described below can be implemented without departing from the gist of the present disclosure. The embodiments and various modifications can be appropriately combined within the scope of the present disclosure. Components having the same function are designated by the same reference numerals, and their descriptions may be omitted. Furthermore, when only a portion of a configuration is mentioned, descriptions elsewhere can be applied to the other portions.

[0015] (First embodiment) <Overall configuration> As shown in Figure 1, the electronic key system for a vehicle according to this embodiment includes an in-vehicle system VS and a portable device 9. The in-vehicle system VS includes a digital key ECU (hereinafter referred to as DK-ECU) 1, which corresponds to the computer of the present disclosure. ECU stands for Electronic Control Unit and refers to an electronic control device. The DK-ECU 1 can also be referred to as a computer, microcomputer, processor, etc.

[0016] <About the DK-ECU 1> The DK-ECU 1 is configured to be able to perform wireless communication (hereinafter referred to as BLE communication) compliant with Bluetooth (registered trademark, the same applies hereinafter) LE with a portable device 9 carried by a user of the vehicle Hv. Furthermore, the DK-ECU 1 is configured to be able to perform BLE channel sounding communication (hereinafter referred to as BLECS communication) with the portable device 9. BLECS communication will be described later. In addition, the following describes a case where the DK-ECU 1 is configured to act as a master in BLE communication with the portable device 9, and the portable device 9 is configured to act as a slave. The term "master" can be read as "central" or "scanner." The term "slave" can be read as "peripheral" or "advertiser."

[0017] The DK-ECU 1 establishes a communication connection with the portable device 9 by receiving an advertising signal from the portable device 9 and transmitting a response signal to the corresponding portable device 9. The advertising signal is a signal for notifying (i.e., advertising) other devices of its presence. The advertising signal and response signal contain information indicating the sender and, if necessary, the destination. The sender and destination may be expressed by an identifier such as a device ID. The advertising signal (or response signal) also contains information indicating whether a digital key app (described later) is running. In another embodiment, the vehicle electronic key system may be configured so that the portable device 9 acts as the master in communication with the DK-ECU 1, and the DK-ECU 1 acts as the slave. The roles of each device are interchangeable. Furthermore, the functions and configurations of the DK-ECU 1 and the portable device 9 can be appropriately changed in accordance with the role interchange.

[0018] In the present disclosure, a wireless signal conforming to the BLE standard is referred to as a BLE signal. Furthermore, among BLE signals, an advertisement channel signal may be referred to as an advertisement signal, and a data channel signal may be referred to as a data signal. Of the 40 channels of BLE communication, channels with channel numbers 37 to 39 correspond to advertisement channels. Furthermore, channels with channel numbers 0 to 36 correspond to data channels. The definitions and specific frequency values ​​of advertisement channels and data channels may be determined according to the BLE standard. Furthermore, in accordance with changes to the BLE standard, the configuration of the present disclosure may be appropriately modified and implemented so as to conform to the changed standard.

[0019] <About the Portable Device 9> The portable device 9 is a portable, general-purpose information processing terminal equipped with a BLE communication function. Various communication terminals, such as a smartphone or a wearable device, can be used as the portable device 9. A wearable device is a device worn on the user's body and can have a variety of shapes, such as a wristband, a watch, a ring, glasses, or earphones. The portable device 9 can also be called a user device or a key device.

[0020] The portable device 9 may be a smart key, which is a dedicated device serving as an electronic key for the vehicle Hv. The smart key is a device that is transferred to the owner along with the vehicle Hv when the vehicle Hv is purchased. The smart key can be considered one of the accessories of the vehicle Hv. The smart key may also be called a vehicle portable device, key fob, key card, access key, etc.

[0021] As shown in FIG. 2, the mobile device 9 includes a device control unit 90, a display 95, a touch panel 96, a BLE module 97, and the like.

[0022] The device control unit 90 is a module that controls the overall operation of the portable device 9. The device control unit 90 is configured as a computer that includes, for example, a device processor 91, a memory 92, a storage 93, an input / output circuit 94, and the like. The device processor 91 is, for example, a CPU (Central Processing Unit). The memory 92 is a volatile storage medium such as RAM (Random Access Memory). The storage 93 includes a non-volatile storage medium such as flash memory. The input / output circuit 94 is a circuit that allows the device control unit 90 to receive signals from other components within the portable device 9 and output signals to other components.

[0023] The storage 93 may store a device ID, a key code used in wireless authentication processing with the DK-ECU 1, and the like. The key code may also be called an encryption key. A digital key app, which is application software that causes the portable device 9 to function as a key for the vehicle hybrid vehicle, may be installed in the storage 93. Note that in this disclosure, the application may be simply referred to as the app.

[0024] The digital key app is used for secure communication with the DK-ECU 1 and for responding to inquiries / requests from the DK-ECU 1. Furthermore, when the mobile device 9 and the DK-ECU 1 are connected for communication, the digital key app enables the user holding the mobile device 9 to unlock / lock the vehicle hybrid's doors by touching a sensor or switch on the door handle, a user far from the vehicle hybrid's doors by touching a button on the digital key app (remote key entry (RKE)), sounding a buzzer (panic) to locate a vehicle hybrid parked in a large parking lot, and / or displaying the vehicle hybrid's status (e.g., remaining fuel, tire pressure, interior temperature, and / or the fact that the vehicle hybrid's doors have been unlocked) on the mobile device 9 (vehicle status confirmation). These various functions of the digital key app can be executed when the digital key app is running on the mobile device 9. In other words, if the digital key app is not running on the mobile device 9, the user cannot access or use the vehicle Hv.

[0025] The display 95 is, for example, a liquid crystal display or an organic EL display. The display 95 displays an image in response to an input signal from the device control unit 90. The touch panel 96 is, for example, a capacitive touch panel, and is layered on the display 95. The touch panel 96 is an input device provided in the portable device 9. The display 95 and the touch panel 96 correspond to an interface through which the user inputs a password into the portable device 9 for logging in to the digital key app, inputs an operation for pairing the portable device 9 with the in-vehicle system VS, and instructs the execution of the above-mentioned functions from a location away from the vehicle Hv.

[0026] The BLE module 97 is a communication module for performing BLE communication. The BLE module 97 includes a reception strength detection unit, which is a functional unit that measures the reception strength of a received signal. The measurement value of the reception strength may also be called RSSI (Received Signal Strength Indicator). In addition to the received data, the BLE module 97 outputs data indicating the measured reception strength together with transmission source information to the device control unit 90.

[0027] Furthermore, the BLE module 97 is configured to be able to transmit and receive a continuous wave (CW) signal of a predetermined waveform as a signal for CS (Channel Sounding) ranging, which will be described later, in addition to a modulated signal for data communication. The CW signal may be a sine wave or a triangular wave. The BLE module 97 may have a configuration similar to that of a BLE module 2, which will be described later, and which is provided in the in-vehicle system VS. The description of the BLE module 2 may be partially or entirely applicable to the BLE module 97.

[0028] To initiate BLE communication with the in-vehicle system VS, the device control unit 90 causes the BLE module 97 to transmit an advertising signal at a predetermined transmission interval (advertising interval). In the present disclosure, this advertising signal corresponds to a connection request signal. Furthermore, the device control unit 90 establishes a BLE communication connection with the in-vehicle system VS based on the BLE module 97 receiving a connection request transmitted from the in-vehicle system VS in response to the advertising signal. The device control unit 90 may perform authentication processing via wireless communication (hereinafter, wireless authentication processing) based on the establishment of a communication connection with the in-vehicle system VS. The wireless authentication processing may be performed, for example, using a challenge-response method. In this case, the device control unit 90 may generate a response code using a key code in response to receiving a challenge code from the in-vehicle system VS and return the response code to the in-vehicle system VS.

[0029] Furthermore, based on a request from the in-vehicle system VS, the device control unit 90 executes communication for CS ranging using the BLE module 97. For example, based on a request from the in-vehicle system VS, the device control unit 90 causes the BLE module 97 to transmit a CW signal of a specified channel (or frequency). The interaction between the device control unit 90 and the in-vehicle system VS will be described separately later.

[0030] <Regarding the In-Vehicle System VS> As shown in FIG. 3 , the in-vehicle system VS includes a DK-ECU 1, a BLE module 2 as a communication unit, a body ECU 4, an action sensor 5, and an actuator 6. The DK-ECU 1, the BLE module 2, and the body ECU 4 are connected to each other so as to be able to communicate with each other, for example, via an in-vehicle network. Various standards can be adopted for the in-vehicle network, such as Controller Area Network (CAN: registered trademark), Ethernet (registered trademark), and FlexRay (registered trademark). However, the following description will be given assuming that CAN is adopted as the in-vehicle network standard. The body ECU 4 is connected to the action sensor 5 and the actuator 6. The connection configuration between devices disclosed herein is an example and can be changed as appropriate.

[0031] The DK-ECU 1 executes processing to determine the position of the portable device 9 relative to the vehicle Hv based on the BLE signals (more specifically, the RSSI ranging results and CS ranging results of the BLE signals) communicated between the BLE module 2 of the in-vehicle system VS and the BLE module 97 of the portable device 9. For example, the DK-ECU 1 calculates ranging data indicating the distance (device distance) between each BLE module 2 and the portable device 9 based on the BLECS signals communicated between the multiple BLE modules 2 and the portable device 9. Then, based on the ranging data, the DK-ECU 1 detects the position of the portable device 9 by determining the position of the portable device 9 relative to the vehicle Hv or by determining whether the portable device 9 is located in an entry area (nearby area) outside the vehicle or in an engine start area inside the vehicle. Because the portable device 9 corresponds to the user, detecting the device position corresponds to detecting the user's position.

[0032] 3, the DK-ECU 1 includes a main controller 11, a CAN controller 15, a power supply circuit 16, etc. The main controller 11 is a computer that executes various processes related to detecting the position of the portable device 9. The main controller 11 includes a main processor 12, a memory 13, and a storage 14. The main processor 12 is, for example, a CPU that executes predetermined processes according to software. The memory 13 is a volatile storage medium, for example, a RAM.

[0033] The storage 14 includes a non-volatile storage medium such as a flash memory. The storage 14 stores a device location detection program executed by the main processor 12 and a communication connection management program for managing the number of mobile devices that are simultaneously connected for communication. For example, the execution of the communication connection management program by the main processor 12 corresponds to the execution of a communication connection management method corresponding to the communication connection management program. The storage 14 also stores registration data that registers the device ID (e.g., a unique Bluetooth address) of the mobile device 9 that is the owner device, and the device IDs of mobile devices 9 that have previously established a BLE communication connection. The storage 14 also stores data indicating the installation position of each BLE module 2 in the vehicle Hv.

[0034] The CAN controller 15 executes communication processing according to the CAN protocol with other components of the in-vehicle system VS in response to instructions from the main controller 11, etc. The CAN controller 15 executes transmission processing, reception processing, and arbitration processing as communication processing. For example, when a data frame is stored in a reception buffer, the CAN controller 15 executes reception processing and transmits the received data to the main controller 11. The reception processing includes processing to determine whether the received data frame is an invalid data frame due to corruption or the like through a form check, a stuff check, a cyclic redundancy check, etc. Furthermore, when the data frame is stored in the transmission buffer, the CAN controller 15 transmits the data to other components of the in-vehicle system VS while arbitrating with other transmission signals through arbitration processing.

[0035] The power supply circuit 16 is a circuit module that supplies power to the main controller 11, the CAN controller 15, etc. The power supply circuit 16 converts the voltage (e.g., battery voltage) input from the power cable into a voltage suitable for the operation of the main controller 11 and the CAN controller 15, and outputs it to each section.

[0036] The BLE module 2 is a communication module for performing BLE communication. In this embodiment, a plurality of BLE modules 2 are provided in the vehicle Hv. Each BLE module 2 is also referred to as an anchor. For example, as shown in FIG. 4 , the plurality of BLE modules 2 includes, for example, an interior front anchor 2A, an interior rear anchor 2B, a right front anchor 2C, a right rear anchor 2D, a left rear anchor 2E, and a left front anchor 2F. The interior front anchor 2A and the interior rear anchor 2B are BLE modules 2 disposed in the vehicle cabin. The right front anchor 2C, the right rear anchor 2D, the left rear anchor 2E, and the left front anchor 2F are BLE modules 2 disposed on the exterior surface of the vehicle Hv. The configuration and performance of each BLE module 2 may be substantially the same regardless of the installation location. Note that the example of the arrangement of the plurality of BLE modules 2 shown in FIG. 4 is merely an example, and the plurality of BLE modules 2 may be disposed in different locations.

[0037] The BLE module 2 is configured to be able to transmit and receive a CW signal for each channel (or frequency) as a signal for CS ranging in addition to a modulated signal for data communication. Furthermore, the BLE module 2 is configured to be able to scan for advertising signals using power supplied from an on-board battery even while the vehicle Hv is parked.

[0038] The body ECU 4 is an ECU that detects user operations (actions) on the vehicle Hv based on input signals from the action sensors 5 and operates the actuators 6 in response to the detected user operations. Examples of actions on the vehicle Hv include locking and unlocking operations, sitting down, pressing a start switch, and depressing a brake pedal. The action sensors 5 include, for example, door sensors provided on the exterior door handles, start switches, brake pedal sensors, and seat sensors. The body ECU 4 can detect touch operations on the door sensors as unlocking and locking operations. The door sensors are sensors that detect user operations to unlock and lock the doors of the vehicle Hv. The door sensors may be touch sensors or push-button switches. The start switch is a push-button switch that the user uses to turn on and off the driving power supply.

[0039] The actuator 6 is, for example, a lock motor or a mechanism for switching on / off the headlights and welcome lamps. The lock motor is a motor that switches between locking and unlocking the doors. The welcome lamp is an in-vehicle lighting device that illuminates the road surface near the doors. The welcome lamp is arranged on the side mirror, side sill, the lower end of the door panel, etc. The welcome lamp can be turned on, for example, when a user holding the mobile device 9 with the digital key app activated enters an intermediate area (described later).

[0040] When the body ECU 4 detects a predetermined event that requires detection of the location of the portable device 9, such as an unlocking operation, the body ECU 4 may transmit an event occurrence notification signal to the DK-ECU 1. Based on the event occurrence notification signal input from the body ECU 4, the DK-ECU 1 may execute control and processing related to the detection of the device location.

[0041] <Configuration and Function of BLE Module> Next, a description will be given of an example of the configuration and function of the BLE module 2. The BLE module 2 includes an RF core 21, an antenna 22, and a BLE controller 23, as shown in FIG.

[0042] The antenna 22 is an antenna element for transmitting and receiving radio waves in the frequency band used for BLE communication, i.e., the 2.4 GHz band. The 2.4 GHz band can be understood as a frequency band that includes multiple channels (Ch 0 to 39) used for BLE communication. The antenna 22 is electrically connected to the RF core 21. The channel can also be referred to as a frequency. Of the multiple channels assigned to BLE, the channel used for actual communication (in other words, the frequency / channel in use) changes over time by frequency hopping or in response to instructions from the BLE controller.

[0043] The RF core 21 is a circuit module that performs signal processing for transmitting and receiving radio signals. The RF core 21 may include a modulation circuit, a demodulation circuit, a frequency conversion circuit, an amplifier circuit, a local oscillator, etc. The RF core 21 also has input / output terminals for outputting signals to the antenna 22 and receiving signals from the antenna 22.

[0044] In this embodiment, the antenna 22 includes multiple antennas 22A and 22B having different polarization axes, such as horizontal polarization and vertical polarization. These multiple antennas 22A and 22B are provided to realize polarization diversity, which ensures the reception level of the CS ranging signal by switching between the multiple antennas 22A and 22B with different polarization axes when performing CS ranging communication. In the following description, when the two antennas 22A and 22B are collectively described, they will be simply referred to as antenna 22. For example, when performing data communication with the mobile device 9 via BLE communication, the RF core 21 uses only one of the multiple antennas 22A and 22B. On the other hand, when performing CS ranging communication with the mobile device 9, the RF core 21 switches between the multiple antennas 22A and 22B. This switching between the multiple antennas 22A and 22B is performed while the CS ranging signal maintains the same frequency. This makes it possible to transmit and receive CS ranging signals via multiple signal paths, making it possible to measure the phase of the CS ranging signal with high accuracy through CS ranging communication.

[0045] The BLE module 97 of the portable device 9 may or may not have multiple antennas. For example, if the BLE module 97 of the portable device 9 has two antennas, the BLE module 2 of the in-vehicle system VS and the BLE module 97 of the portable device 9 can cooperatively switch between their two antennas while the CS ranging signal maintains the same frequency, thereby enabling transmission and reception of the CS ranging signal through four signal paths. Furthermore, if the BLE module 97 of the portable device 9 does not have multiple antennas, the CS ranging signal may be transmitted and received through multiple signal paths by simply switching between the multiple antennas 22A and 22B in the BLE module 2 of the in-vehicle system VS.

[0046] The RF core 21 is connected to the BLE controller 23 so as to be able to communicate with each other. The RF core 21 demodulates a signal received by the antenna 22 and provides the demodulated signal to the BLE controller 23. The RF core 21 also modulates transmission data input from the BLE controller 23 and emits the data as radio waves from the antenna 22. The RF core 21 may be realized as an IC chip (i.e., a transmission / reception IC).

[0047] The RF core 21 is configured to be able to transmit and receive modulated signals for data communication as well as CW signals for each channel (frequency) as a function for CS ranging. The RF core 21 also includes a reception strength detection unit E1 and a reception phase detection unit E2. The reception strength detection unit E1 is a functional unit that measures the reception strength of a received signal. The reception strength detection unit E1 outputs data indicating the detected reception strength to the BLE controller 23.

[0048] The reception phase detector E2 is a circuit that detects the reception phase, which is the phase angle of the reception signal relative to the output signal of the local oscillator, when a CW ranging signal is received. The phase angle of the reception signal relative to the output signal of the local oscillator corresponds to the reception phase. In other words, the reception phase can be interpreted as the output value of the arctangent whose input value is the ratio of the Q (Quadrature-Phase) component to the I (In-Phase) component of the reception signal. The magnitude of the I component corresponds to the strength of the in-phase component of the reception signal. The magnitude of the Q component corresponds to the strength of the quadrature component of the reception signal. The I component is obtained by multiplying the reception signal by the carrier wave output by the local oscillator. The Q component is obtained by multiplying the reception signal by a phase-shifted signal, which is a 90° phase shifter of the output signal of the local oscillator. The phase-shifted signal can be obtained by passing the output signal of the local oscillator through a phase shift circuit, which shifts the phase by 90°.

[0049] The local oscillator is a circuit that generates a sine wave or cosine wave of a carrier frequency, and can be realized using, for example, a voltage-controlled oscillator (VCO). The reception phase may be determined based on an IQ signal whose frequency has been reduced to baseband. The detected reception phase information is used to calculate a device distance indicating the distance between the BLE module 2 and the mobile device 9.

[0050] The RF core 21 provides the BLE controller 23 with the detected value of the reception phase of the CW ranging signal in association with information indicating the frequency in use (e.g., a channel number). The RF core 21 detects the reception phase of the CW signal as part of the ranging process every time the frequency in use is switched. That is, the BLE controller 23 is provided with data indicating the reception phase for each frequency. At this time, the data indicating the reception phase for each frequency may include multiple reception phases due to the above-mentioned polarization diversity.

[0051] The BLE controller 23 is a microcomputer that controls the RF core 21. The BLE controller 23 includes a processor 24, a memory 25, a storage 26, an input / output circuit 27, etc. The BLE controller 23 controls the exchange of data with the DK-ECU 1. Specifically, the BLE controller 23 provides the DK-ECU 1 with received data input from the RF core 21 sequentially or based on a request from the DK-ECU 1. The BLE controller 23 also outputs transmission data input from the DK-ECU 1 to the RF core 21.

[0052] The BLE controller 23 includes a CS ranging unit F1, a reception strength acquisition unit F2, and a report processing unit F3. The CS ranging unit F1, the reception strength acquisition unit F2, and the report processing unit F3 may each be a software module or a hardware module. The following descriptions of the CS ranging unit F1, the reception strength acquisition unit F2, and the report processing unit F3 can be replaced with the BLE module 2 or the BLE controller 23 as appropriate.

[0053] The CS ranging unit F1 is a functional unit that performs CS ranging. CS ranging here refers to a process of generating distance data indicating the device distance based on a position-related value (reception phase), which is a parameter indicating the length of the propagation path of a wireless signal from the BLE module 2 to the mobile device 9. CS ranging includes a process of performing bidirectional or unidirectional communication with the mobile device 9 to acquire the reception phase, which is a position-related value. CS ranging can also be called High Accuracy Distance Measurement (HADM) or phase difference ranging. In the present disclosure, a series of processes including communication for CS ranging may also be referred to as CS ranging processing.

[0054] In this embodiment, the CS ranging unit F1 acquires the reception phase for each frequency as a CS ranging process and calculates the device distance based on the reception phase. The reception phase is the phase difference between the CW ranging signal transmitted by the portable device 9 and the CW ranging signal received by the BLE module 2. The reception phase can be called the transmission / reception phase difference, the single frequency phase difference, or the first-order phase difference.

[0055] The CS ranging unit F1 can acquire the reception phase for each frequency using, for example, a one-way method. The one-way method is a method in which, assuming that the initial phase of the CW signal for each frequency transmitted from the portable device 9 is constant, the reception phase of the CW signal transmitted from the portable device 9 is used as the basis for calculating the inter-frequency phase difference. The reception phase (in other words, the single-frequency phase difference) used as the basis for calculating the inter-frequency phase difference can also be acquired using a so-called passive two-way method or active two-way method. The passive two-way method and active two-way method will be described later in a separate supplementary explanation.

[0056] 6 is a flowchart showing an example of a CS ranging process using a one-way method. The CS ranging process includes a preparation phase for adjusting the conditions for performing ranging, a collection phase for collecting reception phases by actually transmitting and receiving CW ranging signals, and a calculation phase for calculating distances based on the collected reception phases for each frequency. In this disclosure, wireless communication for acquiring position-related values ​​(reception phases), such as transmitting and receiving CW ranging signals, is also referred to as CW ranging communication.

[0057] Step S100 is a step in which the BLE module 2 transmits a CS ranging start request to the mobile device 9. The CS ranging start request is a BLE signal requesting the mobile device 9 to start CS ranging. The CS ranging start request can be transmitted using a data channel after a communication connection with the mobile device 9 is established. In step S105, the mobile device 9 returns a positive response signal (so-called Ack) to the BLE module 2 based on receiving the CS ranging start request.

[0058] In step S110, the BLE module 2 transmits a ranging setting notification signal based on receiving an ACK in response to the CS ranging start request from the mobile device 9. The ranging setting notification signal indicates parameters for performing CS ranging communication. The parameters for performing ranging communication may include an initial phase setting value, a hopping interval, a frequency transition amount, and an initial frequency. The initial phase setting value is basically set to 0. The hopping interval indicates the time required for switching frequencies, in other words, the time required for maintaining one frequency. The hopping interval may be the same as or different from the connection interval used in data communication. The frequency transition amount is a parameter indicating the amount of frequency change when switching frequencies. The frequency transition amount may be the same value as the hop increment used in data communication or may be different. If the frequency transition amount is the same value as the hop increment used in data communication, the frequency transition amount in CS ranging communication may be determined by the hop increment. The initial frequency is the frequency of the CW ranging signal transmitted first in a series of ranging communications. The frequency information may be expressed, for example, by a channel number, or may be expressed separately from the channel number.

[0059] In step S115, upon receiving the ranging setting notification signal, the portable device 9 returns an Ack to the BLE module 2. In step S120, upon receiving the Ack from the portable device 9, the BLE module 2 transitions to a state in which it can receive a signal of the initial frequency, i.e., a reception standby state.

[0060] In step S125, the portable device 9 starts transmitting a CW ranging signal at the initial frequency when a predetermined time has elapsed since returning the Ack. The transmission of the CW ranging signal can be stopped, for example, when a certain time has elapsed since the start of the transmission. The CW transmission time, which is the time for which the CW ranging signal is continuously transmitted, may be set to be shorter than the hopping interval. Note that the portable device 9 may start transmitting the CW ranging signal after receiving the ranging setting notification signal and then receiving a CW ranging transmission request from the BLE module 2.

[0061] When the BLE module 2 receives the CW ranging signal from the portable device 9, in step S130, it detects the reception phase and stores the reception phase data together with frequency information (e.g., channel number) in the memory 25. In step S140, the BLE module 2 and the portable device 9 automatically switch the operating frequency at the hopping interval previously agreed upon in step S110. The changed frequency can be uniquely determined from the frequency before the change and the previously agreed frequency transition amount.

[0062] After switching the operating frequency, the portable device 9 transmits a CW ranging signal of the new operating frequency in step S145. The BLE module 2 also switches the operating frequency, thereby transitioning to a state in which it can receive a signal of the new operating frequency. Then, in step S150, the BLE module 2 observes and acquires the reception phase at the frequency after the switching.

[0063] The BLE module 2 and the portable device 9 repeat the frequency switching process and the reception phase acquisition process described above until they have collected the reception phases for all frequencies for which the reception phases should be acquired (for example, all channels (Ch 0 to 36) that can be used for data communication). The BLE module 2 and the portable device 9 may end the repeated process when they have collected the reception phases for all predetermined necessary frequencies. The required number here may be the same as the number of data channels, or may be more or less than that. The greater the number of frequencies for which the reception phases are collected, the higher the ranging accuracy, which will be described later. On the other hand, the time and power consumption required for ranging communication may increase. The required number may be 3, 4, 5, 8, 10, 16, 37, 81, etc.

[0064] In step S160, the BLE module 2 transmits a ranging end notification signal to the portable device 9 at the timing when the necessary number of reception phases for each frequency have been collected. The ranging end notification signal is a data signal for notifying the end of CW ranging communication. Upon receiving the ranging end notification signal, the portable device 9 transitions to a normal data communication mode. The normal data communication mode corresponds to a state in which predetermined data such as audio data can be transmitted and received. The transmission and reception of the ranging end notification signal is an optional element and may be omitted. Upon receiving the ranging end notification signal, the portable device 9 may return an ACK to the BLE module 2.

[0065] When the CS ranging unit F1 has completed collection of the reception phase for each frequency, it calculates a phase change coefficient (α) in step S170. The phase change coefficient is a parameter that indicates the degree to which the reception phase changes in response to a change in frequency. The phase change coefficient can also be called the phase change degree, the phase shift amount, or the correlation coefficient between phase and frequency.

[0066] The phase change coefficient is calculated based on the reception phase observed at two arbitrary frequencies, for example, a first frequency and a second frequency. Assuming that the difference frequency between the first and second frequencies is Δf, the inter-frequency phase difference between the reception phases observed at the first and second frequencies is Δφ, and the phase change coefficient is α, the relationship is α = Δφ / Δf. The inter-frequency phase difference (Δφ) is the difference between the reception phases observed at two different frequencies. The inter-frequency phase difference (Δφ) can also be called a two-frequency phase difference or a quadratic phase difference. The inter-frequency phase difference (Δφ) corresponds to the amount of phase angle shift due to a change in the frequency used.

[0067] The CS ranging unit F1 of this embodiment calculates a regression line showing the relationship between frequency and reception phase based on the reception phase for each frequency, and uses the slope of the regression line as the phase change coefficient. This is because the slope of the regression line indicates the amount of change in reception phase relative to the amount of frequency change. The regression line can be calculated using various methods, such as the least squares method. If the regression line is expressed as y = ax + b, the coefficient a of x corresponds to the slope of the regression line. Note that in the above equation, "x" is a variable corresponding to frequency, and "y" is a variable corresponding to reception phase. The regression line can also be referred to as an approximate line.

[0068] The CS ranging unit F1 may provisionally calculate a first regression line based on all observed reception phase data, and then recalculate a second regression line after excluding values ​​(so-called outliers) whose distance from the provisionally calculated first regression line is equal to or greater than a predetermined value. In this case, the CS ranging unit F1 may use the slope of the second regression line as a phase change coefficient. In this way, the phase change coefficient used in distance calculation may be determined based on a regression line whose population is data excluding outliers. This configuration can improve the accuracy of the inter-frequency phase difference and, ultimately, the ranging accuracy.

[0069] The CS ranging unit F1 may calculate the inter-frequency phase difference (Δφ), the differential frequency (Δf), and the phase change coefficient for each combination of frequencies for which the reception phase can be observed. The CS ranging unit F1 may use the average or median of the phase change coefficients for each combination of frequencies as the phase change coefficient to be used in distance calculation.

[0070] In step S180, the CS ranging unit F1 calculates the device distance (D) using a phase change coefficient (α) generated based on reception phase information at multiple frequencies. If the device distance is D, the differential frequency Δf and the inter-frequency phase difference (Δφ) have the relationship D∝C·Δφ / (2π·Δf)=C·α / 2π. The parameter "C" in the above equation indicates the propagation speed of radio waves (3×10^8 m / sec). The CS ranging unit F1 calculates the device distance based on this relationship. For example, the CS ranging unit F1 can calculate the device distance using equation 1: D=k·C·α / 2π. The parameter k in equation 1 is a design value and is set to 1.0 or 0.5. The value of k can be determined depending on whether the transmission and reception phase difference is calculated as a phase change coefficient for one way or a round trip. The CS ranging unit F1 stores the calculated device distance data in memory 25.

[0071] In another aspect, when the CS ranging unit F1 calculates a hypothetical value (d) of the device distance using Δf and Δφ for each frequency combination and adopts the average or median value of these as the device distance, the hypothetical value (d) of the device distance for a certain frequency combination can be calculated using d = k·C·Δφ / (2π·Δf), etc.

[0072] Note that, among the series of processes shown in FIG. 6 , the steps executed by the BLE module 2 are executed in cooperation with the CS ranging unit F1 and the RF core 21. In the example described above, the BLE module 2 determines and notifies the implementation conditions for CS ranging communication, but this is not limited to this. The portable device 9, rather than the BLE module 2, may determine the specifications for implementing ranging communication and transmit the ranging setting notification signal. Furthermore, the execution entity of each step can be interchanged. The above sequence may be performed by the portable device 9 acting as the master. Furthermore, the function of calculating the phase change coefficient in the CS ranging unit F1 may be included in the DK-ECU 1. In this case, the CS ranging unit F1 collects the reception phase for each frequency and transmits the collected data to the DK-ECU 1.

[0073] The reception strength acquisition unit F2 is configured to acquire data indicating the reception strength of signals from the portable device 9 for each frequency, which is a location-related value for BLE communication, from the RF core 21. The DK-ECU 1 can roughly identify the area and location of the portable device 9 based on the reception strength data from at least one BLE module 2 (reception strength acquisition unit F2). While the BLE module 2 is connected to and communicating with the portable device 9, it periodically transmits and receives data signals for communication confirmation with the portable device 9. The reception strength acquisition unit F2 acquires reception strength data when the data signal for communication confirmation is received and transmits the data to the DK-ECU 1. Note that communication for communication confirmation can be performed at connection intervals. Communication for communication confirmation may also be performed each time channel hopping is performed.

[0074] The signal used to detect the reception strength is not limited to a data signal for communication confirmation. It may be a normal data signal or an advertising signal. Furthermore, the signal used to detect the reception strength may be a signal for CS ranging communication. Unless otherwise noted, the reception strength in the following description refers to the reception strength of a signal transmitted from the mobile device 9.

[0075] The report processing unit F3 transmits the device distance calculated by the CS distance measuring unit F1 and reception strength data indicating the reception strength acquired by the reception strength acquisition unit F2 to the DK-ECU1 (main controller 11). The transmission of various data may be performed periodically. The report processing unit F3 may also transmit various data in response to a request from the main controller 11.

[0076] <Interaction between the portable device 9 and the in-vehicle system VS> Here, the interaction between the portable device 9 and the in-vehicle system VS will be described. The interaction between the portable device 9 and the in-vehicle system VS is performed after the portable device 9 is registered (paired) as an owner device in the in-vehicle system VS. Therefore, first, an example of an owner device registration process for registering (pairing) the portable device 9 as an owner device in the in-vehicle system VS will be described.

[0077] In the owner device registration process, if the portable device 9 is a communication terminal such as a smartphone, the user performs biometric authentication, inputs a passcode, or the like on the portable device 9. This makes it possible to confirm that the portable device 9 is being operated by the user himself / herself in the owner device registration process.

[0078] The user uses the portable device 9 to request the start of the owner device registration process from a management server (not shown). In response to this request, the management server creates a password. The created password is distributed to the portable device 9 and the in-vehicle system VS via wireless communication.

[0079] In the in-vehicle system VS, when the main switch of the vehicle Hv is turned on, a button for starting pairing between the owner device and the in-vehicle system VS is displayed, for example, on a multimedia screen provided in the vehicle cabin. When the user operates the pairing start button, the pairing process is initiated. At this time, the in-vehicle system VS preferably authenticates the user by, for example, holding a smart key having a short-range wireless communication function such as NFC near the main switch. Alternatively, the user may be authenticated by entering a passcode identifying the user on the multimedia screen. The pairing start button may also be displayed on the display 95 of the portable device 9, rather than on the multimedia screen provided in the vehicle cabin.

[0080] When the pairing start button is operated, an advertising signal is transmitted from the slave (DK-ECU1 or portable device 9) in the BLE communication to the central (portable device 9 or DK-ECU1). The central in the BLE communication receives the advertising signal from the slave. Then, when the central confirms that the slave is a legitimate communication partner based on the password distributed by the management server, it responds to the advertising signal and returns a connection request. A BLE communication connection between the central and the slave is established based on the slave's receipt of the connection request from the central.

[0081] When a BLE communication connection between the central and the slave is established, the central and the slave mutually generate encryption keys and exchange them via BLE communication. After the authenticity of the exchanged encryption key is verified, the exchanged encryption key is stored in a storage medium such as each storage. After pairing, the data signal of the BLE communication is encrypted using the exchanged encryption key. This ensures the security of the BLE communication between the DK-ECU 1 and the portable device 9.

[0082] As part of the owner device registration process, the DK-ECU 1 may determine whether the portable device 9 supports CS ranging communication. If the DK-ECU 1 determines that the portable device 9 supports CS ranging communication, the DK-ECU 1 can associate the ID (portable device ID) of the portable device 9 with the set CS compatibility flag, register it, and save it.

[0083] There are several possible methods for determining whether the portable device 9 supports CS ranging communication. For example, when the portable device 9 is registered as an owner device with the in-vehicle system VS, the BLE module 97 of the portable device 9 and the BLE module 2 of the in-vehicle system VS exchange various information, including their respective identification information (portable device IDs). During this exchange, for example, information regarding the wireless communication method supported by the in-vehicle system VS may be transmitted to the portable device 9, or conversely, information regarding the wireless communication method supported by the portable device 9 may be transmitted to the in-vehicle system VS. By including whether or not the portable device 9 supports CS ranging communication in the information regarding the wireless communication method supported by the portable device 9, the in-vehicle system VS can determine whether or not the portable device 9 supports CS ranging communication based on the received information regarding the wireless communication method supported by the portable device 9.

[0084] Alternatively, during the above-described exchange between the portable device 9 and the in-vehicle system VS, the in-vehicle system VS can, for example, inquire about setting values ​​related to CS ranging communication from the portable device 9. If the portable device 9 responds to the inquiry from the in-vehicle system VS with a setting value related to CS ranging communication, the in-vehicle system VS can determine that the portable device 9 supports CS ranging communication. On the other hand, if the portable device 9 does not respond to the inquiry from the in-vehicle system VS or receives a response indicating that the portable device 9 does not support CS ranging communication, the in-vehicle system VS can determine that the portable device 9 does not support CS ranging communication.

[0085] In addition, confirmation of whether the portable device 9 supports CS ranging communication may be performed each time the DK-ECU 1 and the portable device 9 start BLE communication, rather than when the portable device 9 is registered as an owner device.

[0086] Finally, the management server is notified that the portable device 9 has been registered as an owner device with the in-vehicle system VS of the vehicle Hv, thereby completing the owner device registration process. After the owner device registration process is completed, the slave in the BLE communication (the DK-ECU 1 or the portable device 9) starts transmitting an advertising signal. The central in the BLE communication (the portable device 9 or the DK-ECU 1) starts scanning for the corresponding advertising signal. Note that the following describes an example in which the portable device 9 is a slave in the BLE communication.

[0087] When the portable device 9 and the in-vehicle system VS are not yet connected for communication, the portable device 9 transmits an advertising signal at an interval equal to a predetermined advertising interval plus a random time (so-called advertising delay), as shown in Fig. 7. The BLE module 2 of the in-vehicle system VS enters a reception standby state at a predetermined scan interval and scans for signals from the portable device 9. The size of the scan window, which corresponds to the length of time for which the reception standby state is maintained, may be designed as appropriate.

[0088] The lengths of the scan interval and the advertising interval can also be set to various values. The various interval values ​​are preferably set to values ​​that enable a quick connection when the user approaches the vehicle Hv. The advertising interval can be set to a value from 20 milliseconds to 400 milliseconds, such as 37.5 milliseconds, 50 milliseconds, 80 milliseconds, or 100 milliseconds. Of course, the advertising interval may be set to a value greater than 400 milliseconds as long as it complies with the BLE standard. The advertising interval may also be set to a value shorter than the scan interval.

[0089] In response to the advertising signal from the portable device 9, the in-vehicle communication system VS returns a connection request, thereby establishing a communication connection between the portable device 9 and the in-vehicle system VS. After the BLE communication connection between the portable device 9 and the in-vehicle system VS is established, the BLE module 97 of the portable device 9 and the BLE module 2 of the in-vehicle system VS periodically perform data communication at a predetermined connection interval via BLE communication, as shown in FIG. 8 . The content of the communication may be various, such as a communication confirmation. The connection interval may be set to a value between 7.5 milliseconds and 200 milliseconds, such as 30 milliseconds or 40 milliseconds. The connection interval may also be set to a value greater than 200 milliseconds as long as it complies with the BLE standard.

[0090] Furthermore, after a BLE communication connection is established between the portable device 9 and the in-vehicle system VS, the DK-ECU 1 of the in-vehicle system VS performs CS ranging communication with the portable device 9. CS ranging communication is preferably initiated when the received signal strength of the BLE signal exceeds a predetermined strength threshold or when the distance between the positions measured by the respective GPS receivers falls below a distance threshold. When any of the above-described conditions for initiating CS ranging communication is satisfied, the DK-ECU 1 can transmit a request to start CS ranging to the BLE module 2.

[0091] FIG. 9 illustrates the interaction between the portable device 9 and the in-vehicle system VS when performing CS ranging communication. The CS ranging interval, which is the interval at which the BLE module 2 performs CS ranging communication, can be set to, for example, twice or three times the connection interval. By making the CS ranging interval longer than the interval at which periodic data communication is performed, power consumption can be reduced. However, the CS ranging interval may be the same as the connection interval. Note that "CS-Ranging Interval" in FIG. 9 indicates the CS ranging interval. In one CS ranging communication, CW signals may be transmitted and received at multiple frequencies. Furthermore, one CS ranging communication may transmit and receive a CW signal at a single frequency. The duration of one CS ranging communication can be adjusted depending on the length of the CW signal, etc.

[0092] When the portable device 9 and the in-vehicle system VS perform data communication and CS ranging communication via their respective BLE modules 2 and 97, as shown in Fig. 9, the DK-ECU 1 can, for example, perform received signal strength ranging based on the received signal strength of the signal for data communication, and can also perform CS ranging through CS ranging communication. On the other hand, if the portable device 9 does not support CS ranging communication, normal data communication is performed between the BLE module 2 and the portable device 9, as shown in Fig. 8, for example. In this case, the DK-ECU 1 can perform received signal strength ranging using the received signal strength for data communication.

[0093] The CS ranging communication may be terminated, for example, when the portable device 9 is powered off and the BLE communication connection is disconnected, or when the received signal strength of the BLE signal falls below a predetermined strength threshold. The strength threshold for terminating the CS ranging communication may be the same as or different from the strength threshold for starting the CS ranging communication. Furthermore, the CS ranging communication may be terminated if no action is taken on the vehicle Hv for a predetermined time after the CS ranging communication is started. Alternatively, the CS ranging communication may be terminated when the user gets into the vehicle Hv and turns on the start switch. When any of the above-described conditions for terminating the CS ranging communication is satisfied, the DK-ECU 1 can transmit a request to stop CS ranging to the BLE module 2.

[0094] When the CS ranging communication is terminated in response to the user turning on the start switch, the CS ranging communication may be started in response to the opening and closing of the door of the vehicle Hv. This makes it possible to detect the position of the portable device 9 through the CS ranging communication, for example, when the portable device 9 is taken out of the vehicle Hv while the vehicle Hv is temporarily stopped with the start switch not turned off.

[0095] <Functions of Main Controller 11> The main controller 11 of the DK-ECU 1 includes, as functional blocks, a communication control unit G1 and a position determination unit G2, as shown in FIG. 10. The communication control unit G1 is a software or hardware module that controls the operation of the BLE module 2. For example, the communication control unit G1 performs a communication connection management process that limits the number of mobile devices 9 that can communicate with each other at the same time to a predetermined upper limit. The communication control unit G1 also performs a CS ranging process using the BLE module 2.

[0096] The position determination unit G2 detects the position of the portable device 9 by determining the device position relative to the vehicle Hv based on the CS ranging result and / or the received signal strength ranging result. The device position can be expressed by a plurality of areas / zones that are set in advance in the vehicle Hv, such as an engine start area ESA inside the vehicle, an entry area (nearby area) outside the vehicle, an intermediate area and a far area outside the vehicle.

[0097] The entry area outside the vehicle refers to an area where the distance from the vehicle Hv is less than an arbitrary proximity determination value EA1 of 5 m or less, such as 1.0 m, 1.5 m, or 2 m, as shown in FIG. 11 . The entry area is an area where the doors, trunk, etc. of the vehicle Hv can be unlocked / locked in response to a user operation detected by the action sensor 5. Regarding the unlocking of the doors of the vehicle Hv, only the door that has been unlocked may be unlocked, or all doors including the door that has been unlocked may be unlocked. Regarding the locking of the vehicle Hv, when a user holding the portable device 9 locks any door, all doors and the trunk may be locked.

[0098] The far area refers to an area where the distance from the vehicle Hv is equal to or greater than a predetermined far distance determination value EA2. The far distance determination value is a parameter for determining that the portable device 9 is not present near the vehicle Hv. The far distance determination value is set to, for example, 10 m, 12 m, or 15 m. However, in the far area, the user can perform operations such as locking / unlocking the doors and trunk of the vehicle Hv, sounding a buzzer, and displaying the vehicle status by activating the digital key app on the portable device 9.

[0099] The intermediate area refers to an area intermediate between the far area and the entry area. The intermediate area may be a so-called welcome area in which predetermined welcome control, such as turning on exterior vehicle lights, is executed upon entry of the portable device 9 into the area. The intermediate area may also be an area in which predetermined control, such as tracking the device location of the portable device 9 or shortening the location determination cycle, is executed / started, which is not executed when the portable device 9 is located far outside the vehicle. The intermediate area may also be called a standby area or a peripheral area. Alternatively, the intermediate area may be an area in which a user can use a function to remotely park / exit the vehicle Hv.

[0100] The entry area, intermediate area, and far area are subdivisions of the outside area. Furthermore, as shown in FIG. 11 , the position determination unit G2 may determine whether the portable device 9 is present inside the vehicle as an engine start area ESA where the main switch (power switch for running) of the vehicle Hv can be turned on / off.

[0101] As described above, the position determination unit G2 of this embodiment determines a stay area, which is an area where the portable device 9 is located. In another aspect, the position determination unit G2 may calculate device position coordinates instead of or in addition to determining the stay area. The device position coordinates refer to the position coordinates of the portable device 9 located in a two-dimensional / three-dimensional coordinate system based on a predetermined position of the vehicle Hv. The calculation of the device position coordinates can be performed using a method similar to three-point positioning or multi-point positioning in the technical fields of GPS and position estimation.

[0102] The main controller 11 transmits device position data, which is data indicating the determined device positions, to a predetermined ECU such as the body ECU 4. The main controller 11 may periodically update the device position data. The main controller 11 may also generate and update the device position data in response to the occurrence of a predetermined event.

[0103] <Communication Connection Management Process> Next, the communication connection management process executed in the in-vehicle system VS of the vehicle electronic key system of this embodiment, which limits the number of portable devices 9 that are connected for communication at the same time to a predetermined upper limit of connections, will be described with reference to the flowchart of Fig. 12. Note that the process shown in the flowchart of Fig. 12 is executed at each scan interval in accordance with the scan window period when the DK-ECU 1 acts as the master in BLE communication with the portable devices 9.

[0104] In step S200 of the flowchart in FIG. 12 , the DK-ECU 1 of the in-vehicle system VS determines whether it has received an advertising signal corresponding to a connection request from the portable device 9. If the DK-ECU 1 is a slave, it determines whether it has received a connection request returned from the portable device 9 in response to the advertising signal it transmitted. As described above, the advertising signal and / or connection request includes information indicating the sender and information indicating whether the digital key application is running. If it is determined that it has received an advertising signal or a connection request, the DK-ECU 1 proceeds to step S205. On the other hand, if it is determined that it has not received an advertising signal or a connection request, the DK-ECU 1 proceeds to step S250.

[0105] In step S205, the DK-ECU 1 acquires, as priority information (priority determination information), information indicating the sender and information indicating whether the digital key application is running, which are included in the received advertising signal or connection request. The process in step S205 corresponds to the acquisition unit in the present disclosure. Note that in this embodiment, the priority information may be acquired during BLE data communication after the BLE communication connection is established in step S210 (described later).

[0106] Then, in step S210, the DK-ECU 1 accepts the connection request from the portable device 9 by transmitting a response signal (connection request) to the portable device 9 that transmitted the advertising signal. Alternatively, the DK-ECU 1 may accept the connection request from the portable device 9 by receiving the connection request from the portable device 9. This establishes a BLE communication connection between the DK-ECU 1 and the portable device 9. This enables the DK-ECU 1 to perform BLECS ranging communication with the portable device 9, thereby enabling the device distance to the portable device 9 to be calculated with high accuracy. As a result, the distance to the portable device 9 and the area to which the location of the portable device 9 belongs can be calculated more accurately. After accepting the connection request, the DK-ECU 1 performs BLECS communication with the portable device 9.

[0107] In the next step S215, the DK-ECU 1 determines whether the portable device 9 is not running the digital key app and whether the distance to the portable device 9 determined by BLECS ranging communication corresponds to the far area, or whether the identified location of the portable device 9 belongs to the far area.

[0108] In this embodiment, as shown in FIG. 13 , when the location of the portable device 9 is in the indoor area, the nearby area, or the intermediate area, the portable device 9 is considered a target for communication connection, regardless of whether the digital key app is running, as long as the connection limit is not exceeded. This is because a user of a portable device 9 located in the intermediate area or an area closer to the vehicle Hv is likely to intend to access or use the vehicle Hv. On the other hand, when the location of the portable device 9 is in the distant area, the portable device 9 is considered a target for communication connection only if the digital key app is running. This is because if the digital key app is not running on the portable device 9 and the portable device 9 is located in the distant area, it is unclear whether the user of the portable device 9 intends to access or use the vehicle Hv. On the other hand, even if the portable device 9 is located in the distant area, if the digital key app is running on the portable device 9, the user of the portable device 9 may intend to access or use the vehicle Hv. Therefore, by excluding a portable device 9 located in the distant area and not running the digital key app from the target for communication connection, unnecessary communication connections with the portable device 9 can be prevented. 13 also applies to portable devices 9 that should be given priority for communication connection, such as owner devices. If the number of portable devices 9 that are targets for communication connection at the same time exceeds the upper limit of connections, the portable devices 9 that will perform communication connection and the portable devices 9 that will disconnect communication connection are classified by the process described below.

[0109] If it is determined in step S215 that the digital key app is not running and that the portable device 9 is in a distant area, the DK-ECU 1 proceeds to step S220 and disconnects the communication connection with the portable device 9 that was once established.

[0110] If the DK-ECU 1 determines in step S215 that the digital key app is running and / or that the portable device 9 belongs to an intermediate or nearby area rather than a distant area, the DK-ECU 1 proceeds to step S225. In step S225, the DK-ECU 1 determines whether the number of portable devices 9 currently connected to the DK-ECU 1 exceeds the upper limit. For example, if the number of portable devices 9 currently connected to the DK-ECU 1 reaches the upper limit before receiving a connection request from a new portable device 9 in step S200, establishing a connection with the new portable device 9 will cause the number of portable devices 9 currently connected to the DK-ECU 1 to exceed the upper limit. If the DK-ECU 1 determines that the number of portable devices 9 currently connected to the DK-ECU 1 exceeds the upper limit, the DK-ECU 1 proceeds to step S230. On the other hand, if the DK-ECU 1 determines that the number of portable devices 9 currently connected to the DK-ECU 1 is equal to or less than the upper limit, the DK-ECU 1 proceeds to step S255.

[0111] In step S230, the DK-ECU 1 determines whether the portable device 9 that has newly established a communication connection is a priority device that should be given priority for communication connection. Whether the portable device 9 is a priority device can be determined based on priority information acquired from the portable device 9 through communication with the portable device 9. The priority information includes information for determining whether the portable device 9 is an owner device and information for determining whether the portable device 9 is a friend device that has been permitted to access or use the vehicle Hv by the user who owns the owner device and is communicating with the DK-ECU 1 for the first time via the BLE module 2.

[0112] For example, a device ID can be used as information for determining whether a device is an owner device. Because the device IDs of owner devices are registered in the DK-ECU 1, it is possible to determine whether the device is an owner device from the device ID. In this embodiment, if the portable device 9 is an owner device, it is considered to have priority information that indicates that the portable device 9 should be prioritized for communication connection over other portable devices. Furthermore, for example, a device ID and assigned information (e.g., part of a key code) assigned to the friend device by the owner device can be used as information for determining whether the portable device 9 is communicating for the first time. Once the DK-ECU 1 establishes a communication connection with the portable device 9, the DK-ECU 1 registers the device ID of the portable device 9 as a device with which it has previously established a communication connection. Therefore, it is possible to determine from the device ID whether the portable device 9 is communicating for the first time. Furthermore, it is possible to determine from the assigned information that the portable device 9 is a friend device that is authorized to access or use the vehicle Hv.

[0113] More specifically, the friend device can acquire and store grant information (e.g., an attestation package including an IRK, etc.) indicating that the friend device has been granted access rights and usage rights to the vehicle Hv from the owner device in advance via a management server. Therefore, when a friend device that is communicating for the first time approaches the vehicle Hv, the friend device can use the stored grant information to return a connection request in response to an advertising signal between the in-vehicle system VS and the friend device, thereby establishing a communication connection.

[0114] When a BLE communication connection is established between a friend device and the in-vehicle system VS, the in-vehicle system VS checks the attestation package held by the friend device. This allows the in-vehicle system VS to confirm that the device with which the communication connection is established is a friend device. Thereafter, similar to when registering the owner device, the friend device and the in-vehicle system VS mutually generate encryption keys and exchange them via BLE communication. The in-vehicle system VS associates the device ID and encryption key of the friend device and registers it as a friend device. At this time, the in-vehicle system VS may determine whether the friend device supports CS ranging communication, and the determination result (e.g., a CS compatibility flag) may also be associated with the device ID and registered.

[0115] Alternatively, in response to instructions from the user of the owner device, the DK-ECU1 can acquire registration information by performing so-called V2X communication with a management server that registers the friend device's ID, authorized authority, expiration date, etc., and then determine whether the device with which the communication connection has been established is a friend device based on the acquired registration information.

[0116] In this embodiment, when the portable device 9 is a friend device with which communication is being performed for the first time, the portable device 9 is considered to have priority information that indicates that the portable device 9 should be given priority over other portable devices for communication connection.

[0117] The reason why the owner device is designated as the priority device is to ensure convenience for the user of the owner device by allowing the owner user to connect to the vehicle Hv with priority over other portable devices 9 when the owner user approaches the vehicle Hv with the intention of using the vehicle Hv. The reason why a friend device that is communicating for the first time is designated as the priority device is because, when a friend device that is permitted to access or use the vehicle Hv connects to the vehicle Hv for the first time, it is considered that the user who owns the friend device (such as a family member or friend, a service provider, or a valet parking attendant) is likely to access or use the vehicle Hv.

[0118] If the DK-ECU 1 determines in step S230 that the newly established portable device 9 is a priority device for which communication connection should be prioritized, the process proceeds to step S245. On the other hand, if the DK-ECU 1 determines that the newly established portable device 9 is not a priority device, the process proceeds to step S235.

[0119] In step S235, the DK-ECU 1 determines the priority order between the currently connected portable device 9 and the portable device 9 that has accepted the connection request and established a new communication connection. Some examples of determining the priority order will be described with reference to FIG. 14.

[0120] FIG. 14A shows a first example of determining priority. In this example, area priority is used as the main priority determining factor, and the closer the area to which the portable device 9 belongs to the vehicle hybrid, the higher the priority is set. Furthermore, the priority based on the activation of the digital key app is used as a sub-priority determining factor, and within the same area, the priority of a portable device 9 that is running the digital key app is set higher than the priority of a portable device 9 that is not running the digital key app. Note that if there are multiple portable devices 9 that are running the digital key app or multiple portable devices 9 that are not running the digital key app within the same area, the priority of the multiple portable devices 9 may be determined based on, for example, the distance from the vehicle hybrid or the driver's seat of the vehicle hybrid. This also applies to the examples described below.

[0121] 14(b) shows a second example of determining the priority order. In this example, priority based on whether the digital key app is running is used as the main priority determination element, and the priority of portable devices 9 running the digital key app is set higher than the priority of portable devices 9 not running the digital key app. Furthermore, priority based on area is used as a sub-priority determination element, and the priority of portable devices 9 running the digital key app that are closer to the vehicle hybrid is set higher, while the priority of portable devices 9 not running the digital key app that are closer to the vehicle hybrid is set higher.

[0122] FIG. 14C shows a third example of determining the priority order. In the third example, the priority order of the portable devices 9 is determined by arbitrarily combining the priority order based on the digital key app's activation and the priority order based on the area as the main priority order determining factors. For example, in the example shown in FIG. 14C, the priority order of the portable devices 9 that are located in the area from the in-vehicle area to the intermediate area and that are running the digital key app is set higher than the priority order of the portable devices 9 that are located in the in-vehicle area and that are not running the digital key app. On the other hand, the priority order of the portable devices 9 that are located in the in-vehicle area and the nearby area and that are not running the digital key app is set higher than the priority order of the portable devices 9 that are located in the distant area and that are running the digital key app. Furthermore, the priority order of the portable devices 9 that are located in the intermediate area and the distant area and that are not running the digital key app is set lower than the priority order of the portable devices 9 that are located in the distant area and that are running the digital key app. However, the third example is merely an example, and the priority order based on the digital key app's activation and the priority order based on the area can be arbitrarily combined to obtain priorities different from those shown in the third example.

[0123] 14(d) shows a fourth example of determining the priority order. The fourth example is based on the first example, and furthermore, the priority order of portable devices 9 that do not have the digital key app running in the intermediate area and the distant area is set taking into consideration whether each portable device 9 is approaching or moving away from the vehicle Hv. Specifically, for portable devices 9 that do not have the digital key app running in the intermediate area and the distant area, the priority order is set so that the priority order of approaching portable devices 9 is higher than the priority order of moving away portable devices 9. Note that whether each portable device 9 is approaching or moving away from the vehicle Hv can be determined from the movement trajectory of the detected position of each portable device 9 and the movement direction predicted from the position of each portable device 9.

[0124] However, the fourth example is merely an example. For example, even in the vicinity area, the priority of each portable device 9 may be set according to its proximity to or distance from the vehicle Hv. Alternatively, for portable devices 9 running the digital key app, whether they are approaching or moving away in each area may be determined, and the priority of each portable device 9 may be set according to the determination result.

[0125] FIG. 14( e) illustrates a fifth example of determining the priority order. In the fifth example, the priority order based on the presence or absence of the same user ID is used as the main priority order determining element, and the priority order of portable devices 9 without the same user ID is set higher than the priority order of portable devices 9 with the same user ID. A portable device 9 without the same user ID refers to a portable device 9 that is not connected to the DK-ECU 1 for communication with another portable device 9 with the same user ID. A portable device 9 with the same user ID refers to a portable device 9 that is connected to the DK-ECU 1 for communication with another portable device 9 with the same user ID. Furthermore, in the fifth example, the priority order based on area is used as a sub-priority order determining element, and the priority order of portable devices 9 without the same user ID is set higher the closer the area to which the portable device 9 belongs to the vehicle hybrid vehicle, and the priority order of portable devices 9 with the same user ID is set higher the closer the area to which the portable device 9 belongs to the vehicle hybrid vehicle.

[0126] The user ID is an identifier unique to each user, and is assigned by the management server when the portable device 9 owned by each user is registered with the management server. When the same user registers multiple portable devices 9 (smartphones, wearable devices, etc.), the management server assigns the same user ID to the multiple portable devices 9. Therefore, the user ID indicates the owner of the portable device 9. When registering the portable device 9 as an owner device or a friend device, the DK-ECU 1 can obtain the user ID from the management server and store it in association with the device ID. Alternatively, if the portable device 9 has a user ID, the DK-ECU 1 may obtain the user ID through communication with the portable device 9.

[0127] As described above, the user ID is an identifier unique to each user. Therefore, the number of portable devices 9 that are communicatively connected to the DK-ECU 1 for each user can be confirmed based on the user ID. As long as one portable device 9 is communicatively connected to the DK-ECU 1, each user can use that portable device 9 to access and use the vehicle Hv. Therefore, there is little need for one user to communicatively connect two or more portable devices 9 to the DK-ECU 1.

[0128] For this reason, in the fifth example, the priority of portable devices 9 that do not have the same user ID is set higher than the priority of portable devices 9 that have the same user ID. Note that the confirmation of the number of portable devices 9 that are communicatively connected to the DK-ECU 1 for each user based on the user ID is performed when the number of portable devices 9 that are communicatively connected to the DK-ECU 1 exceeds the upper limit of connections. In other words, when the number of portable devices 9 that are communicatively connected to the DK-ECU 1 is equal to or less than the upper limit of connections, multiple portable devices 9 with the same user ID can be communicatively connected to the DK-ECU 1. Furthermore, the method of determining priority based on the presence or absence of the same user ID shown in the fifth example may be implemented in any combination with the first to fourth examples described above.

[0129] Several use cases relating to the fifth example are described below. The first use case is when a portable device 9 that has newly established a communication connection is a priority device (i.e., an owner device or a friend device that is communicating for the first time) and the new communication connection causes the upper limit number of connections to be exceeded. In this case, the priority order of the portable devices 9 that are already connected for communication is determined according to the rule shown in FIG. 14( e).

[0130] The second use case is when a newly connected portable device 9 is not a priority device (i.e., a friend device that has been connected in the past), and the new connection exceeds the upper limit of connections. In this case, the priority order is determined between the newly connected portable device 9 and the portable devices 9 that are already connected in communication according to the rule shown in FIG. 14( e).

[0131] For example, in the second use case, if the newly connected portable device 9 is a portable device 9 that does not have the same user ID and the already connected portable devices 9 include a portable device 9 that has the same user ID, the priority of the newly connected portable device 9 is determined to be higher than that of the portable device 9 that has the same user ID. On the other hand, if the newly connected portable device 9 is a portable device 9 that does not have the same user ID and all the already connected portable devices 9 also do not have the same user ID, the priority is determined based on the distance from the vehicle Hv to each portable device 9 and the area where each portable device 9 is located. Even if the newly connected portable device 9 is a portable device 9 that has the same user ID, the priority is determined according to the rule shown in FIG. 14( e).

[0132] If the newly connected portable device 9 and the portable device 9 with the lowest priority among the already connected portable devices 9 belong to the same area and have the same priority, the communication connection may not be switched (i.e., the existing communication connection may not be disconnected), which can prevent an increase in processing load due to frequent switching of communication connections.

[0133] In step S240, the DK-ECU 1 determines whether the priority of the newly connected portable device 9 is higher than the priority of at least one of the currently connected portable devices 9, based on the priority of the currently connected portable device 9 determined in step S235 and the priority of the newly connected portable device 9 that accepted the connection request. If the priority of the newly connected portable device 9 is higher than the priority of at least one of the currently connected portable devices 9, the DK-ECU 1 proceeds to step S245. On the other hand, if the DK-ECU 1 determines that the priority of the newly connected portable device 9 is not higher than the priority of at least one of the currently connected portable devices 9, i.e., if the DK-ECU 1 determines that the newly connected portable device 9 has the lowest priority, the DK-ECU 1 proceeds to step S250.

[0134] In step S245, the DK-ECU 1 disconnects the communication connection with the portable device 9 with the lowest priority among the currently connected portable devices 9. If the DK-ECU 1 determines in step S225 that the newly connected portable device is the priority device, it skips steps S235 and S240 and directly proceeds to step S245. In other words, the newly connected portable device 9, which is the priority device, is not subject to communication disconnection. Instead, a portable device 9 to be disconnected is selected from among the currently connected portable devices 9. Therefore, the priority portable device 9 is given priority over other portable devices 9 in maintaining its communication connection with the vehicle Hv (DK-ECU 1). In step S250, the DK-ECU 1 disconnects the communication connection with the newly connected portable device 9. By the processing of step S245 or S250, the number of currently connected portable devices 9 is limited to the upper limit of the number of connections. In this way, the processes of S210, S225, S227, S230, S234, S235, S240, S245, S250, etc. correspond to the communication connection control unit of the present disclosure.

[0135] In step S210, establishing a communication connection with a new portable device 9 may temporarily cause the number of connected portable devices 9 to exceed the upper limit of connections. However, because one of the communication connections is immediately disconnected in step S220, S245, or S250, the period during which the upper limit of connections is exceeded is extremely short. This makes it possible to sufficiently reduce the impact of delays in communication between the vehicle Hv and each portable device 9.

[0136] Finally, in step S255, the DK-ECU 1 determines whether the scan window period for scanning advertising signals has ended. If so, the DK-ECU 1 ends the process shown in the flowchart of Fig. 12. On the other hand, if not, the DK-ECU 1 returns to step S200 and repeats the above-described process.

[0137] An example of the operation of the process shown in the flowchart of Fig. 12 will be described with reference to Fig. 15. In the example shown in Fig. 15, the upper limit number of connections is set to 4. However, the upper limit number of connections is not limited to 4 and may be 5 or more.

[0138] In the example shown in FIG. 15 , the vehicle Hv is currently connected to four devices: a first device inside the vehicle cabin and four devices outside the vehicle: a second device, a third device, and a fourth device. In other words, the maximum number of devices currently connected to the vehicle Hv at the same time is the maximum number of connections. At a certain point in time, a user carrying device A approaches the vehicle Hv. In this case, the vehicle Hv (DK-ECU 1) establishes a communication connection with device A in response to receiving a connection request from device A. This enables BLECS ranging communication with device A, enabling the position of device A to be detected with high accuracy. Of course, the positions of the first to fourth devices currently connected to the vehicle Hv are also determined with high accuracy through BLECS ranging communication.

[0139] Next, the DK-ECU 1 performs a priority connection determination for device A, which has newly established a communication connection. As described above, the priority connection determination is performed when device A enters a distant area if the digital key app is running, and when device A enters an intermediate area if the digital key app is not running. The priority connection determination includes determining whether device A is a priority device based on the priority information of device A, and determining whether device A has a high priority based on a comparison of the priority of device A with the priorities of the first to fourth devices currently connected. If this priority connection determination determines that the communication connection of device A should be prioritized, the DK-ECU 1 disconnects the communication connection of the device with the lowest priority (the second device in the example of FIG. 15 ) among the first to fourth devices currently connected.

[0140] Second Embodiment Next, a communication connection management system, a communication connection management method, and a vehicle electronic key system to which a computer is applied according to a second embodiment of the present disclosure will be described. Note that the vehicle electronic key system according to this embodiment has the same configuration as the vehicle electronic key system according to the first embodiment. Therefore, a description of the configuration will be omitted.

[0141] In the first embodiment described above, when a connection request (advertisement signal) is received from a new portable device 9, the DK-ECU 1 establishes a communication connection with the new portable device 9, and is able to detect the position of the new portable device 9 with high accuracy using BLECS ranging communication.

[0142] However, while BLECS ranging has high ranging accuracy, it takes a relatively long time to measure the distance to the portable device 9 and detect its position compared to received signal strength ranging in BLE communication. Also, even if it is only for a very short time, the number of portable devices 9 that are connected to and communicating with the DK-ECU 1 will exceed the upper limit of the number of connections.

[0143] In this embodiment, in order to shorten the time required to measure the distance to the mobile device 9 and detect its position and to suppress communication delays of the mobile device 9 currently connected for communication, when a connection request (advertisement signal) is received from a new mobile device 9, priority information of the mobile device 9 is acquired, and received signal strength ranging is performed based on the received signal strength of the received connection request. Then, based on the acquired priority information and the received signal strength ranging and the area to which the distance to the mobile device 9 and its location belong, it is determined whether to establish a communication connection. Therefore, according to this embodiment, although the accuracy of area determination based on the distance and position of the mobile device 9 is somewhat reduced, it is possible to determine whether to establish a communication connection with the new mobile device 9 in a shorter time. Furthermore, according to this embodiment, it is possible to suppress effects such as delays on communication with the currently connected mobile device 9. Furthermore, according to this embodiment, even if the mobile device 9 does not support BLECS ranging communication and only supports BLE communication, it is possible to determine whether to establish a communication connection by taking into account the priority information and the priority of other mobile devices 9.

[0144] 16 is a flowchart showing a communication connection management process according to this embodiment. The same step numbers are assigned to processes that are the same as or similar to those in the flowchart shown in FIG. 12, and the description thereof may be simplified or omitted.

[0145] 16, the process of step S210 in the flowchart of Fig. 12 has been deleted. Therefore, in step S215 of the flowchart of Fig. 16, whether the location of the portable device 9 belongs to the far area (or whether the distance to the portable device 9 corresponds to the far area) is determined based on the received signal strength measurement result based on the received signal strength when a connection request is received from the portable device 9. Note that, as in the first embodiment, the determination of whether the digital key app is running is made based on the information acquired in step S205.

[0146] If it is determined in step S215 that the digital key application is not running and that the portable device 9 is in the remote area, the DK-ECU 1 proceeds directly to step S255 without disconnecting the communication connection. This is because, in this embodiment, a communication connection with a new portable device 9 has not been established, and therefore there is no need to disconnect the communication connection.

[0147] In step S227, the DK-ECU 1 determines whether the number of currently connected portable devices 9 is greater than the upper limit of connections minus one. In this embodiment, at this point, a communication connection has not been established with the new portable device 9 that received the connection request. Therefore, to determine whether the number of currently connected portable devices 9 can be kept below the upper limit of connections even if a communication connection is established with the new portable device 9, the DK-ECU 1 compares the number of currently connected portable devices 9 with the upper limit of connections minus one. Note that steps S230 to S245 in this embodiment are performed in the same manner as in the first embodiment, except that the distance and position of the new portable device 9 are detected based on received signal strength ranging.

[0148] If it is determined in step S227 that the number of currently connected portable devices 9 is equal to or less than the upper limit of connections minus 1, the DK-ECU 1 accepts the connection request from the portable device 9 that transmitted the advertising signal by transmitting a response signal to the portable device 9. This establishes a BLE communication connection between the DK-ECU 1 and the portable device 9.

[0149] In this embodiment, if the DK-ECU 1 determines in step S240 that the priority of the new portable device 9 that has received the connection request is not higher than the priority of the currently connected portable device 9, the communication connection with the new portable device 9 has not been established, and the process proceeds directly to step S255 without disconnecting the communication connection. Furthermore, in this embodiment, if the DK-ECU 1 determines, based on the priority determinations in steps S235 and S240, that the new portable device 9 should be connected to the communication network with priority over the currently connected portable device 9, in step S245, the DK-ECU 1 disconnects the communication connection with the portable device 9 with the lowest priority among the currently connected portable devices 9, and then in step S247, establishes a communication connection with the new portable device 9 by accepting the connection request.

[0150] Fig. 17 is an explanatory diagram illustrating an example of the operation of the process shown in the flowchart of Fig. 16. In the example shown in Fig. 17, as in the example of Fig. 15, the upper limit number of connections is set to four. As shown in Fig. 17, when a user carrying device A approaches the vehicle Hv while communication is currently connected with the first to fourth devices, which is the upper limit number of connections, four, the vehicle Hv (DK-ECU 1) receives a connection request from device A. However, at this point, the DK-ECU 1 does not establish a communication connection with device A.

[0151] First, the DK-ECU 1 performs a priority connection determination for device A, which has recently received a connection request. As in the first embodiment, the priority connection determination is performed when device A enters a distant area if the digital key app is running, and when device A enters an intermediate area if the digital key app is not running. If this priority connection determination determines that the communication connection of device A should be prioritized, the communication connection of the device with the lowest priority (device 2 in the example of FIG. 17 ) among the currently connected first through fourth devices is disconnected. Then, the DK-ECU 1 establishes a communication connection with device A.

[0152] Third Embodiment Next, a communication connection management system, a communication connection management method, and a vehicle electronic key system to which a computer is applied according to a third embodiment of the present disclosure will be described. Note that the vehicle electronic key system according to this embodiment is configured similarly to the vehicle electronic key system according to the first embodiment. Therefore, a description of the configuration will be omitted.

[0153] In the second embodiment described above, when the DK-ECU 1 receives a connection request (advertisement signal) from a new portable device 9, it acquires priority information of the portable device 9 and performs received signal strength ranging based on the received signal strength of the received connection request. Then, it determines whether to establish a communication connection based on the acquired priority information and the distance and position of the portable device 9 obtained from the received signal strength ranging.

[0154] However, as described above, received signal strength ranging has lower ranging accuracy than BLECS ranging, so for example, when determining the priority order between the mobile device 9 currently connected for communication and the mobile device 9 that has received the connection request in step S235, there remains a possibility that an appropriate priority order cannot be determined.

[0155] 18 , the present embodiment is configured such that, before executing step S235 for determining the priority order between the currently connected portable device 9 and the portable device 9 that has received a connection request, the DK-ECU 1 accepts the connection request from the portable device 9 and establishes a BLE communication connection with the portable device 9 in step S232. After accepting the connection request and establishing the BLE communication connection, the DK-ECU 1 executes BLECS communication with the portable device 9. As a result, the DK-ECU 1 can detect the distance and position of the portable device 9 with high accuracy by BLECS ranging, and can therefore appropriately determine the priority order between the currently connected portable device 9 and the portable device 9 that has newly received a connection request.

[0156] On the other hand, in step S215, the determination of whether the portable device 9 belongs to a distant area is made based on the received signal strength measurement result based on the received signal strength when the connection request is received from the portable device 9, as in the second embodiment. Therefore, it is possible to suppress the influence on communication with the currently connected portable device 9 due to the determination of whether the portable device 9 that received the connection request is to be a communication connection target based on the area where the new portable device 9 is located. Furthermore, it is possible to make the determination within a relatively short time.

[0157] Furthermore, in this embodiment, if it is determined in step S230 that the portable device 9 that has newly received the connection request has priority information and is a priority device that should be given priority for communication connection, then in step S234 the DK-ECU 1 establishes a BLE communication connection with the portable device 9. However, the establishment of the BLE communication connection with the portable device 9 that is the priority device may be executed after, in step S245, disconnecting the communication connection of the portable device 9 with the lowest priority among the portable devices 9 currently connected for communication.

[0158] In this embodiment, in step S232, the connection request from the portable device 9 is accepted and a BLE connection is established. Therefore, if in step S240 it is determined that the portable device 9 has the lowest priority, the DK-ECU 1 disconnects the communication connection of the newly established portable device 9 in step S250, as in the first embodiment. Furthermore, after disconnecting the communication connection of the portable device 9 with the lowest priority among the currently connected portable devices 9 in step S245, if a communication connection with the portable device 9 has already been established, the DK-ECU 1 proceeds directly to the processing of step S255.

[0159] Fig. 19 is an explanatory diagram illustrating an example of the operation of the process shown in the flowchart of Fig. 18. In the example shown in Fig. 19, as in the examples of Fig. 15 and Fig. 17, the upper limit number of connections is set to four. As shown in Fig. 19, when a user carrying device A approaches the vehicle Hv while communication connections are in progress with the first to fourth devices, which is the upper limit number of connections, four, the vehicle Hv (DK-ECU 1) receives a connection request from device A. However, at this point, the DK-ECU 1 does not establish a communication connection with device A.

[0160] First, the DK-ECU 1 performs a priority connection determination for device A, which has recently received a connection request. As in the first embodiment, the priority connection determination is performed when device A enters the far area if the digital key app is running, and when device A enters the intermediate area if the digital key app is not running. In this priority connection determination, the DK-ECU 1 determines whether the portable device 9 is a priority device and then establishes a BLE communication connection with the portable device 9. This allows the DK-ECU 1 to appropriately determine the priority order of the first to fourth devices currently connected to the portable device 9 based on the distance and position of the portable device 9 detected with high accuracy by BLECS ranging. If device A has a relatively high priority, the DK-ECU 1 disconnects the communication connection of the device with the lowest priority (the second device in the example of FIG. 19 ) among the first to fourth devices currently connected to the portable device 9.

[0161] Fourth Embodiment Next, a communication connection management system, a communication connection management method, and a vehicle electronic key system to which a computer is applied according to a fourth embodiment of the present disclosure will be described.

[0162] In the first to third embodiments described above, an example has been described in which the vehicle Hv (DK-ECU 1) and the portable device 9 use BLECS communication as a communication method for detecting the distance to and position of the portable device 9 with high accuracy. However, the communication method for detecting the distance to and position of the portable device 9 with high accuracy is not limited to BLECS communication, and for example, ultra-wideband (UWB) communication can also be used. In this embodiment, a configuration for detecting the distance to and position of the portable device 9 using UWB communication and the operation of that configuration will be described. Note that the communication connection management process for limiting the number of portable devices 9 that are simultaneously connected for communication to a predetermined upper limit number can be performed in a similar manner except for the communication method used, and therefore a description thereof will be omitted.

[0163] Fig. 20 is a block diagram showing the configuration of a portable device 9 according to this embodiment. As shown in Fig. 20, the portable device 9 according to this embodiment is obtained by adding a UWB module 98 capable of performing UWB communication to the portable device 9 according to the first to third embodiments. Fig. 21 is a block diagram showing the configuration of an in-vehicle system VS according to this embodiment. As shown in Fig. 21, the in-vehicle system VS according to this embodiment is obtained by adding a plurality of UWB modules 3 capable of performing UWB communication to the in-vehicle system VS according to the first to third embodiments.

[0164] FIG. 22 shows an example of the arrangement of a BLE module 2 and a UWB module 3 according to this embodiment in a vehicle Hv. The BLE module 2 according to this embodiment is capable of performing BLE communication. In the example shown in FIG. 22 , anchors 2A and 2B of the BLE module 2 are arranged at the front and rear of the vehicle interior, respectively. Note that the number of BLE modules 2 may be one. Therefore, received signal strength ranging performed during BLE communication cannot identify the exact location of the portable device 9, and can only roughly detect the area to which the portable device 9 belongs.

[0165] 22, anchors 3A to 3F of multiple UWB modules 3 are respectively arranged in the front and rear of the vehicle, the front right of the vehicle, the rear right of the vehicle, the rear left of the vehicle, and the front left of the vehicle. Therefore, when device distances between at least three UWB modules 3 and the portable device 9 are calculated by performing UWB communication, the position of the portable device 9 can be detected with high accuracy.

[0166] As described above, the in-vehicle system VS and the portable device 9 according to this embodiment are configured to be able to perform UWB communication, which is a wireless communication method using the UWB-IR (Ultra Wide Band - Impulse Radio) system, via their respective UWB modules 3 and 98. Specifically, the in-vehicle system VS and the portable device 9 are configured to be able to transmit and receive impulse-shaped radio waves (hereinafter, referred to as impulse signals) used in UWB communication via their respective UWB modules 3 and 98. The impulse signals used in UWB communication are signals having an extremely short pulse width (e.g., 2 ns) and a bandwidth of approximately 500 MHz or greater (i.e., an ultra-wide bandwidth).

[0167] Note that UWB communication can utilize multiple channels as defined in IEEE 802.15.4z. The in-vehicle system VS can communicate with the portable device 9 using, for example, the fifth channel of UWB communication. Of course, the in-vehicle system VS can also be configured to communicate with the portable device 9 using other channels, such as the third and ninth channels. The third channel has a center frequency of 4492 MHz, the fifth channel has a center frequency of 6489.6 MHz, and the ninth channel has a center frequency of 7987.2 MHz. IEEE (registered trademark) stands for Institute of Electrical and Electronics Engineers. Each channel corresponds to a frequency band of ±250 MHz from the center frequency. Frequencies such as 3.1 GHz to 4.8 GHz and 6.0 GHz to 10.6 GHz can be used in UWB communication.

[0168] Various modulation methods can be used for UWB communication, including on-off keying (OOK), pulse position modulation (PPM), and pulse width modulation (PWM). The on-off keying method represents information (e.g., 0 and 1) by the presence or absence of an impulse signal. The pulse position modulation method modulates the position at which a pulse occurs. The pulse width modulation method represents information by the pulse width. Here, as an example, UWB communication between the in-vehicle system VS and the portable device 9 is performed using the OOK method. Data transmission via UWB communication can be achieved using multiple impulse signals. Hereinafter, a data signal exchanged via UWB communication will be referred to as a UWB signal. Because a UWB signal includes multiple impulse signals, it can also be called a pulse sequence signal.

[0169] The UWB modules 3 and 98 are communication modules for performing UWB communication. The UWB modules 3 and 98 output received data to the DK-ECU 1 and the device control unit 90, respectively. The UWB modules 3 and 98 can also transmit UWB signals corresponding to transmission data based on instructions from the DK-ECU 1 and the device control unit 90, respectively. Furthermore, the UWB modules 3 and 98 can also transmit and receive UWB signals for ranging based on instructions from the DK-ECU 1 and the device control unit 90, respectively. In this way, the operations of the UWB modules 3 and 98 are controlled by the DK-ECU 1 and the device control unit 90, respectively.

[0170] For example, when performing UWB communication with the portable device 9, the DK-ECU 1 can instruct any UWB module 3 to transmit a UWB signal. When the device control unit 90 receives a UWB signal transmitted from the in-vehicle system VS via the UWB module 98, it returns a response signal corresponding to the received signal via the UWB module 98. For example, when the device control unit 90 receives a UWB signal as a search signal, it can return a UWB signal obtained by modulating a code including the device ID of the portable device 9 to the in-vehicle system VS as a response signal. The search signal is a signal used by the in-vehicle system VS to search for the portable device 9 and is a type of signal that requests the portable device 9 to return a response signal. The UWB signals transmitted by the portable device 9 and the in-vehicle system VS may include a code indicating the source or destination.

[0171] It is preferable that the DK-ECU 1 and the device control unit 90 stop the operation of the UWB modules 3, 98 and, for example, put them into a sleep state when a BLE communication connection is not established. In other words, for example, the device control unit 90 preferably activates the UWB module 98 and enables UWB communication based on the establishment of a BLE communication connection with the in-vehicle system VS. This configuration reduces the power consumption of the UWB module 98. In this case, the device control unit 90 may be configured to activate the UWB module 98 on the condition that a UWB ranging start request is received from the DK-ECU 1 via BLE communication after the BLE communication connection with the in-vehicle system VS is established.

[0172] The DK-ECU 1 can instruct the UWB modules 3 to perform UWB ranging, including UWB communication for ranging. For example, the DK-ECU 1 can perform a cyclic measurement process in which each of the multiple UWB modules 3 is instructed to perform a UWB ranging process in turn. The DK-ECU 1 can periodically perform the cyclic measurement process after a BLE communication connection is established between the vehicle Hv and the portable device 9. The DK-ECU 1 may determine the start timing of the cyclic measurement process or dynamically change the cyclic measurement interval based on the received signal strength value of the BLE signal observed within a predetermined period of time. Alternatively, the DK-ECU 1 may perform the cyclic measurement process based on the detection of a predetermined event that requires the location of the portable device 9 to be detected. The above-described UWB ranging process measures the device distance from each UWB module 3 to the portable device 9, and the location of the portable device 9 is detected based on this measured distance. Each UWB module 3 is also referred to as an anchor.

[0173] The UWB modules 3 and 98 are equipped with an antenna for UWB communication, a transmission / reception circuit, a UWB controller, etc. The transmission / reception circuit is a circuit that performs signal processing for modulation and demodulation. The UWB controller is a microcomputer that controls the operation of the UWB modules 3 and 98 and generates UWB ranging data, which will be described next.

[0174] Each UWB module 3 performs UWB ranging processing based on instructions from the DK-ECU 1. The UWB ranging processing is a process of acquiring the propagation time (in other words, the time of flight) of radio waves from each UWB module 3 to the portable device 9 and measuring the device distance based on the acquired propagation time of the radio waves. The UWB ranging processing includes a process of transmitting a UWB signal of a predetermined pattern to the portable device 9 as UWB communication for ranging, and a process of receiving a UWB signal as a response signal from the portable device 9. In the UWB ranging processing, the UWB signal exchanged between the UWB module 3 and the portable device 9 may be a single impulse signal or a pulse sequence signal in which multiple impulse signals are arranged in a predetermined pattern.

[0175] The UWB controller of each UWB module 3 measures the round trip time (RTT), which is the elapsed time from transmitting a UWB signal to receiving a response signal from the portable device 9, and calculates the device distance based on the RTT. The RTT corresponds to the round-trip flight time of the UWB signal. For example, the UWB controller of this embodiment calculates the device distance by multiplying half of the value obtained by subtracting a predetermined correction value from the RTT by the propagation time of the radio waves. The correction value here is a parameter used to offset the response processing time in the portable device 9 and delay times within the UWB module 3. The specific value of the correction value can be designed as appropriate. Each UWB module 3 transmits the calculated device distance to the DK-ECU 1 as UWB ranging data. After performing UWB ranging processing, the UWB module 3 stops operating either autonomously or upon instruction from the DK-ECU 1. Note that the process of converting the RTT to distance may be performed by the main controller 11 of the DK-ECU 1.

[0176] 23 is a diagram showing an example of interaction when UWB ranging communication is performed between the portable device 9 and the in-vehicle system VS. Note that if the portable device 9 supports UWB ranging communication, when the portable device 9 is registered (paired) as an owner device or a friend device in the in-vehicle system VS, the following processing is executed in addition to the processing described in the first embodiment.

[0177] For example, after exchanging encryption keys for BLE communication, the portable device 9 and the in-vehicle system VS generate a UWB Ranging Secret Key (URSK), which is a key used in UWB ranging communication, and share the generated URSK via BLE communication. The URSK can be used to create information that proves that the other party in the UWB ranging communication is a valid party. By having the generated URSK shared between the ECU 1 and the portable device 9, the ECU 1 can perform UWB ranging communication with the portable device 9 as the other party.

[0178] The ECU 1 registers and stores the generated Ursk in association with the ID (portable device ID) of the portable device 9. Preferably, the ECU 1 confirms that UWB ranging communication with the portable device 9 is possible by performing UWB ranging using the generated Ursk.

[0179] As shown in Figure 23, the in-vehicle system VS periodically performs BLE data communication and UWB ranging communication with the portable device 9. For example, the UWB ranging interval, which is the interval at which the DK-ECU 1 causes the UWB module 3 to perform UWB ranging communication, can be set to three or four times the connection interval. By lengthening the UWB ranging interval in this way, it is expected that power consumption can be reduced. However, the CS ranging interval may be the same as the connection interval.

[0180] 23 indicates the UWB ranging interval. One UWB ranging communication may include UWB ranging communications using multiple UWB modules 3. The UWB ranging interval may be set to a value between 150 milliseconds and 400 milliseconds, such as 180 milliseconds or 280 milliseconds.

[0181] The detection of the position of the mobile device using the UWB signal (UWB ranging) described above is preferably started, for example, when the received signal strength of the BLE signal exceeds a predetermined strength threshold, or when the distance between the positions measured by each GPS receiver falls below a distance threshold, because this is expected to have the effect of reducing power consumption.

[0182] When any of the above-described UWB ranging start conditions is satisfied, the DK-ECU 1 can transmit a UWB ranging start request to the multiple UWB modules 3. In response to this UWB ranging start request, the multiple UWB modules 3 transition from a sleep state to an active state. This enables the multiple UWB modules 3 to transmit UWB ranging signals. In other words, the multiple UWB modules 3 are in a sleep state while not performing UWB ranging.

[0183] Like CS ranging communication, UWB ranging communication may be terminated when the portable device 9 is powered off and the BLE communication connection is disconnected, or when the received signal strength of the BLE signal falls below a predetermined strength threshold. The strength threshold for terminating UWB ranging communication may be the same as or different from the strength threshold for starting UWB ranging communication. Furthermore, UWB ranging communication may be terminated if no action is taken on the vehicle for a predetermined time after the start of UWB ranging communication. Furthermore, UWB ranging communication may be terminated when the user gets into the vehicle Hv and turns on the start switch.

[0184] When any of the above-described UWB ranging termination conditions is satisfied, the DK-ECU 1 can transmit a UWB ranging stop request to the multiple UWB modules 3. In response to this stop request, the multiple UWB modules 3 terminate UWB ranging communication. Then, for example, if the multiple UWB modules 3 do not receive a new UWB ranging start request within a predetermined time after terminating UWB ranging communication, they can transition to a sleep state.

[0185] Even when UWB ranging is terminated in response to the user turning on the start switch, UWB ranging communication may be started in response to the opening and closing of the door of the vehicle Hv. This makes it possible to detect through UWB ranging communication that the portable device 9 has been taken out of the vehicle when the vehicle is temporarily stopped with the start switch not turned off.

[0186] (Variations) Although preferred embodiments of the present disclosure have been described above, the present disclosure is not limited to the above-described embodiments and can be implemented in various modifications within the scope of the gist of the present disclosure.

[0187] <Modification 1> For example, in the fourth embodiment described above, the BLE module 2 may be configured to be capable of BLECS communication in addition to BLE communication. The BLE module 2 may be configured to implement both BLECS communication and UWB communication as communication methods for detecting the distance to and position of the portable device 9 with high accuracy. By implementing both BLECS communication and UWB communication, for example, when the portable device 9 is located in a position blocked by a vehicle Hv or a human body, the accuracy of UWB ranging may be reduced. However, BLECS ranging makes it possible to detect the position of the portable device 9 located in such a position with high accuracy.

[0188] To detect the location of the portable device 9 using BLECS ranging, the in-vehicle system VS may include multiple BLE modules (BLE anchors) 2A-2F, as shown in FIG. 24 . In the example shown in FIG. 24 , the multiple BLE modules 2A-2F are arranged in close proximity to multiple UWB modules 3A-3F. In this case, the location of the portable device 9 may be detected based on a result combining UWB ranging results from multiple UWB modules 3 and CS ranging results from multiple BLE modules 2. For example, the DK-ECU 1 may detect the location (area) of the portable device 9 by multilateration based on the device distance measured by UWB ranging and the device distance measured by CS ranging. Alternatively, the device location based on the UWB ranging results and the device location based on the CS ranging results may be separately calculated, and the final device location may be calculated based on the separately calculated device locations. For example, if the calculated positions of the two portable devices 9 match, the matched position may be determined as the final position of the portable device 9. If the calculated positions of the two portable devices 9 do not match, a more likely position of the portable device 9 may be selected based on parameters such as signal strength when the respective distances are measured.

[0189] When multiple BLE modules 2 are used to perform CS ranging, one BLE module 2 may distribute channel information and timing information for performing the CS ranging process to other BLE modules 2, thereby enabling the other BLE modules 2 to also intercept (sniff) the CW signal transmitted from the mobile device 9.

[0190] In BLE, frequency hopping is performed after a communication connection is established, and therefore, normally, only the BLE module 2 that is connected to the communication line can capture the data signal from the mobile device 9. In contrast, with the sniffer technology, by providing channel information and timing information to other BLE modules 2, the other BLE modules 2 can also capture the data signal and CW signal from the mobile device 9. As a result, the other BLE modules 2 can detect the reception strength, reception phase, reception time, etc. of the signal from the mobile device 9 without being connected to the mobile device 9. Therefore, a configuration that applies the sniffer technology has the advantage that multiple BLE modules 2 can perform CS ranging processing in parallel.

[0191] <Modification 2> In the above-described embodiment, the BLE module 2 is disposed outside the housing of the DK-ECU 1. However, this is not limiting. For example, the BLE module 2 may be disposed inside the housing of the DK-ECU 1.

[0192] <Modification 3> In the above-described embodiment, the UWB module 3 measures the RTT, which is the elapsed time from transmitting a UWB signal to receiving a response signal from the portable device 9, and calculates the device distance based on the RTT. However, in addition to or instead of measuring the RTT, the UWB module 3 can measure the arrival angle or arrival time difference of the UWB signal, and detect the position of the portable device 9 based on the measured arrival angle or arrival time difference. For example, if the UWB module 3 is configured to measure the arrival angle of the UWB signal in addition to measuring the RTT of the UWB signal, it becomes possible to detect the position (or area) of the portable device 9 around the vehicle Hv with a fewer number of UWB modules 3.

[0193] <Modification 4> The BLE controller 23 may calculate the device distance using the RTT instead of or in addition to the inter-frequency phase difference. The RTT measured by the BLE controller 23 is the time from transmitting a predetermined BLE signal requesting a response to receiving a response signal from the mobile device 9. Sending and receiving a signal for measuring the RTT also corresponds to an example of CS ranging communication. Calculating the phase change coefficient or the RTT essentially corresponds to calculating the device distance. Therefore, the process of generating data indicating the device distance, such as the phase change coefficient or the RTT, based on the phase of the signal received from the mobile device 9 or the time of flight, is also included in the concept of CS ranging processing. Calculating the distance also includes generating data that indirectly indicates the distance.

[0194] <Modification 5> The communication method between the BLE module 2 and the mobile device 9 is not limited to BLE, and may be Bluetooth Classic, etc. Bluetooth-compliant wireless communication includes both BLE communication and communication compliant with Bluetooth Classic.

[0195] In the above embodiment, the ECU 1 is configured as an independent electronic control unit in the in-vehicle system VS, but this is not limiting. For example, the functions of the ECU 1 may be integrated with other ECUs configured to realize other functions.

[0196] (Supplementary Information on the Method of Obtaining Single-Frequency Phase Difference) The BLE module 2 may obtain the single-frequency phase difference for each frequency using an active two-way system or a passive two-way system, and may use the obtained single-frequency phase difference to calculate the inter-frequency phase difference. Here, an overview of the active two-way system and the passive two-way system will be described.

[0197] The active two-way system is a system in which an initiator and a reflector transmit and receive CW signals to each other, detect the phase difference between the transmitted signal and the received signal, and use these two phase differences to identify the single-frequency phase difference. The active two-way system includes a process in which the initiator and the reflector transmit and receive CW signals to each other, and a process in which the reflector transmits the observed received phase (θr) to the initiator.

[0198] An initiator is a device that starts communication, in other words, a device that requests a response. A reflector is a device that returns a response. In the above embodiment, the BLE module 2 corresponds to the initiator, and the mobile device 9 corresponds to the reflector.

[0199] If the initial phase of the initiator is δi, the initial phase of the reflector is δr, the single-frequency phase difference that should be observed according to the one-way distance between the initiator and the reflector is φ, and the target frequency is f, then the relationships θr = φ + δi - δr and θi = φ - δi + δr hold. Based on this relationship, the average value of θi and θr is the single-frequency phase difference (φ) in which the initial phase components of the initiator and the reflector are canceled out. The active two-way system corresponds to a system in which the average value of the reception phase at the initiator and the reception phase at the reflector is calculated as the single-frequency phase difference. Note that, since the phase difference due to one-way propagation is assumed here, the average value of θi and θr is taken as the single-frequency phase difference. As another aspect, if the phase difference due to round-trip propagation is assumed as the single-frequency phase difference, the single-frequency phase difference can be calculated as θi + θr.

[0200] The passive two-way system also involves an initiator and a reflector transmitting and receiving CW signals to and from each other. The difference from the active two-way system is that the reflector reflects the received phase of the CW signal transmitted from the initiator in the initial phase of the transmitted signal. For example, if the received phase at the reflector is θr, the reflector transmits a CW signal expressed as z(t) = A·exp{-i(ωt + θr + 2πn)}. A represents amplitude. ω is the angular frequency corresponding to the target frequency (f), and has the relationship ω = 2πf. n is a natural number corresponding to the interval between when the reflector receives the CW signal and when it transmits the CW signal. In this system, the received phase observed by the initiator does not include the reflector's initial phase component. The received phase observed by the initiator is the same value as when the CW signal is received after being reflected by a reflective object such as a wall. As a result, the initiator can calculate the single-frequency phase difference without acquiring the reception phase from the reflector. The passive two-way system has the advantage over the active two-way system that the reflector does not need to transmit a reception phase message. As described above, the single-frequency phase difference and, therefore, the inter-frequency phase difference can be calculated using various methods.

[0201] (Applicable Targets of the Present Disclosure) The present disclosure is applicable to a variety of vehicles that travel on roads. That is, the present disclosure can be installed in a variety of vehicles that can travel on roads, such as four-wheeled vehicles, two-wheeled vehicles, three-wheeled vehicles, and vehicles with more than four wheels. Furthermore, the present disclosure can be applied to applications other than vehicles that require detection of the position of a user holding a mobile device 9.

[0202] (Supplementary Note 1) This specification discloses the following technical ideas and combinations thereof. The combinations of the following technical ideas apply not only to a position detection system, but also to a position detection method and a computer that executes the position detection method.

[0203] <Technical Idea 1> A communication connection management system that manages communication connections between an object (Hv) and a plurality of portable devices (9), comprising: a communication unit (2) that is provided in the object and that wirelessly communicates with the portable devices; the communication unit has a set upper limit on the number of connections for the portable devices that can establish communication connections with the communication unit; an acquisition unit (S205) that, when the portable device is a portable device that should be given priority for communication connection, acquires, from the portable device, priority information indicating that the portable device is a portable device that should be given priority for communication connection, by wireless communication with the portable device via the communication unit; and a communication connection control unit (S210, S225, S227, S230, S234, S235, S240, S245, S247, S250) that, when communication connections with the plurality of portable devices that make up the upper limit are ongoing, and the acquisition unit acquires the priority information by communication with a new portable device, disconnects the communication connection with any of the portable devices that make up the upper limit of connections currently ongoing, and establishes a communication connection with the new portable device.

[0204] <Technical Concept 2> The communication connection management system according to Technical Concept 1, wherein the priority information is information indicating that the portable device is an owner device.

[0205] <Technical Idea 3> The communication connection management system described in Technical Idea 2, wherein the priority information is information indicating that the friend device is authorized by the user who holds the owner device to access or use the object and is communicating with the communication unit of the object for the first time.

[0206] <Technical Idea 4> The communication connection management system according to any one of Technical Ideas 1 to 3, wherein the communication connection control unit determines a priority order for communication connections among the mobile devices with an upper limit number of currently connected communication connections, and disconnects the communication connection of the mobile device with the lowest priority order.

[0207] <Technical Idea 5> The communication connection management system described in any one of Technical Ideas 1 to 4, wherein, when the acquisition unit does not acquire the priority information through communication with a new portable device while the communication connection control unit is currently connected to the maximum number of portable devices, the communication connection control unit determines a priority order for communication connections among the maximum number of portable devices currently connected to the maximum number of portable devices and the new portable device, and disconnects the communication connection of the portable device with the lowest priority order.

[0208] <Technical Idea 6> The communication connection management system according to any one of Technical Ideas 1 to 5, wherein the communication connection control unit determines a priority for the communication connection in consideration of at least one of the distance between the portable device and the object, an area defined based on the object to which the portable device belongs, a movement trajectory of the portable device, a movement direction of the portable device, whether the portable device is running an application for accessing the object, and a user ID indicating the owner of the portable device.

[0209] <Technical Idea 7> The communication connection management system according to Technical Idea 6, wherein the communication connection control unit sets a higher priority for the portable device closer to the object than for the portable device farther from the object.

[0210] <Technical Idea 8> The communication connection management system according to Technical Idea 6 or 7, wherein the communication connection control unit sets a higher priority for the portable device moving towards the object than for the portable device moving away from the object.

[0211] <Technical Idea 9> The communication connection management system described in any one of Technical Ideas 6 to 8, wherein the communication connection control unit sets the priority of the portable device that does not have the same user ID higher than the priority of the portable device that has the same user ID.

[0212] <Technical Idea 10> The communication connection management system according to any one of Technical Ideas 1 to 9, wherein the communication connection control unit does not establish a communication connection with the new portable device, even if the new portable device is the portable device that should be given priority for communication connection, until the new portable device approaches the target object to within a predetermined distance or a predetermined area from the target object.

[0213] <Technical Idea 11> The communication connection management system according to Technical Idea 10, wherein the communication connection control unit determines whether to establish a communication connection with the new portable device when the new portable device is running an application for accessing the object, regardless of whether the new portable device has the priority information, even if the new portable device is outside a predetermined distance or a predetermined area from the object.

[0214] <Technical Idea 12> The communication connection management system according to Technical Idea 11, wherein, when a new portable device that is present at a predetermined distance or outside a predetermined area from the object has the priority information and is running an application for accessing the object, the communication connection control unit establishes a communication connection with the new portable device in priority to the portable devices that are currently connected at a maximum number of connections.

[0215] <Technical Idea 13> The communication connection management system according to Technical Idea 11 or 12, wherein, when the new portable device that is located at a predetermined distance or outside a predetermined area from the object does not have the priority information and has an application running for accessing the object, the communication connection control unit determines a priority order for the communication connection between the new portable device and the portable devices that are within the upper limit of the number of connections currently connected for communication, and establishes a communication connection with the new portable device when the priority order of the new portable device is higher than the priority order of at least one of the portable devices that are within the upper limit of the number of connections currently connected for communication.

[0216] <Technical Idea 14> The communication connection management system according to any one of Technical Ideas 1 to 13, wherein the communication unit executes Bluetooth Low Energy Channel Sounding (BLECS) communication, which transmits and receives continuous wave signals whose frequency is changed periodically, as communication with the mobile device.

[0217] <Technical Concept 15> The communication connection management system according to any one of Technical Concepts 1 to 13, wherein the communication unit performs UWB communication for transmitting and receiving an ultra-wideband (UWB) signal as communication with the portable device.

[0218] <Technical Idea 16> The communication connection management system according to any one of Technical Ideas 1 to 13, wherein the communication unit performs Bluetooth Low Energy Channel Sounding (BLECS) communication for transmitting and receiving continuous wave signals whose frequency is changed periodically, and UWB communication for transmitting and receiving ultra-wideband (UWB) signals, as communication with the portable device.

[0219] (Supplementary Note 2) The various flowcharts shown in this disclosure are merely examples, and the number of steps constituting the flowcharts and the order in which the processes are executed may be changed as appropriate. The terms "wireless signal," "BLE signal," "data," "message," "packet," "frame," "package," "data set," "information," and the like used in this disclosure may be interpreted interchangeably.

[0220] The apparatus, system, and method described herein may be implemented by a special-purpose computer including a processor programmed to execute one or more functions embodied in a computer program. The apparatus and method described herein may be implemented using dedicated hardware logic circuits. The apparatus and method described herein may be implemented by one or more special-purpose computers configured by a combination of a processor executing a computer program and one or more hardware logic circuits. For example, some or all of the functions of the BLE controller 23 may be implemented in hardware. Implementations of certain functions in hardware include implementations using one or more integrated circuits (ICs). The processor (computing core) may be a CPU, an MPU, a GPU, a data flow processor (DFP), or the like. Some or all of the functions of the BLE controller 23 may be implemented using a system-on-chip (SoC), an integrated circuit (IC), or a field-programmable gate array (FPGA). The concept of an IC also includes an application-specific integrated circuit (ASIC). Furthermore, the computer program may be stored as instructions executed by a computer on a computer-readable non-transient tangible storage medium. Examples of the program storage medium include a hard-disk drive (HDD), a solid-state drive (SSD), and flash memory. The present disclosure also encompasses programs for causing a computer to function as the BLE controller 23 or the main controller 11, and non-transient tangible storage media such as semiconductor memory on which the programs are stored.

Claims

1. A communication connection management system for managing communication connections between an object (Hv) and multiple mobile devices (9), A communication unit (2) provided on the object and performing wireless communication with the portable device, An acquisition unit (S205) acquires information from the mobile device via wireless communication with the mobile device via the communication unit to determine whether the mobile device is a priority device that should be given priority in communication connection, The system includes a communication connection control unit (S210, S225, S227, S230, S234, S235, S240, S245, S247, S250) that controls the communication connection with the mobile device, The aforementioned communication unit has a defined upper limit on the number of mobile devices that can establish a communication connection at the same time. The aforementioned communication connection control unit, Based on the information acquired by the acquisition unit, the mobile device is determined to be the preferred device. When a communication connection is established with multiple of the above-mentioned mobile devices up to the connection limit, and a connection request is received from a new device which is a new mobile device, and if the new device is the preferred device, the communication connection with one of the above-mentioned mobile devices up to the connection limit that is currently connected will be terminated, and a communication connection with the new device will be established. Furthermore, the communication connection control unit is configured to determine the friend device, which is a mobile device having title information issued by the owner device, as the priority device if it is communicating with the communication unit for the first time.

2. The communication connection control unit determines that a mobile device registered as an owner device is the preferred device, as described in Claim 1.

3. The communication connection management system according to claim 1, wherein when the number of connections, which is the number of mobile devices currently connected to a communication network, is equal to or greater than the maximum number of connections, the communication connection control unit determines a priority order for communication connections among the mobile devices currently connected to a communication network, and disconnects the communication connection of the mobile device with the lowest priority.

4. The communication connection management system according to claim 1, wherein, when the number of connections, which is the number of mobile devices currently connected, reaches the maximum number of connections, the communication connection control unit receives a connection request from a new device, and if the new device is not the priority device, it determines a priority order for communication connections among the mobile devices currently connected and the new device, and disconnects the communication connection of the mobile device with the lowest priority.

5. The communication connection management system according to claim 3 or 4, wherein the communication connection control unit determines the priority of communication connections taking into consideration the distance between the mobile device and the object, an area defined with respect to the object to which the mobile device belongs, the movement trajectory of the mobile device, the direction of movement of the mobile device, whether the mobile device has launched an application for performing access to the object, and at least one of the user IDs indicating the owner of the mobile device.

6. The communication connection control unit sets a higher priority for the mobile device that is closer to the object than for the mobile device that is further away from the object, as described in claim 5.

7. The communication connection control unit sets the priority of the mobile device moving toward the object higher than the priority of the mobile device moving away from the object, as described in claim 5.

8. The communication connection control unit sets the priority of the mobile device that does not have the same user ID higher than the priority of the mobile device that has the same user ID, according to claim 5.

9. The communication connection management system according to any one of claims 1 to 3, wherein the communication connection control unit does not establish a communication connection with the new device, even if the new device is the preferred device, until the new device approaches the object to a predetermined distance or area from the object.

10. The communication connection management system according to claim 9, wherein the communication connection control unit determines whether or not to establish a communication connection with the new device, regardless of whether the new device is the preferred device, if the new device is running an application for performing access to the object, even if it is outside a predetermined distance or area from the object.

11. The communication connection management system according to claim 10, wherein the communication connection control unit establishes a communication connection with the new device, prioritizing it over the number of mobile devices currently connected, if the new device is located at a predetermined distance or outside a predetermined area from the object, and is the preferred device and has launched an application for accessing the object.

12. The communication connection management system according to claim 10, wherein the communication connection control unit determines a priority order for communication connection among the maximum number of connected mobile devices and the new device when the new device is located at a predetermined distance or outside a predetermined area from the object and is not the preferred device, and is running an application for accessing the object, and establishes a communication connection with the new device when the priority of the new device is higher than the priority of at least one of the connected mobile devices among the maximum number of connected mobile devices.

13. The communication unit performs Bluetooth Low Energy Channel Sounding (BLECS) communication, which transmits and receives a continuous wave signal whose frequency is periodically changed, as communication with the mobile device, according to any one of claims 1 to 3.

14. The communication unit performs UWB communication, which involves sending and receiving ultra-wideband (UWB) signals, as communication with the mobile device, according to any one of claims 1 to 3.

15. The communication unit performs Bluetooth Low Energy Channel Sounding (BLECS) communication, which transmits and receives a continuous wave signal whose frequency is periodically changed, and UWB communication, which transmits and receives an ultra-wideband (UWB) signal, as communication with the mobile device, the communication connection management system according to any one of claims 1 to 3.

16. A communication connection management system for managing communication connections between an object (Hv) and a plurality of portable devices (9), A communication unit (2) provided on the object and performing wireless communication with the portable device, An acquisition unit (S205) acquires information from the mobile device via wireless communication with the mobile device via the communication unit to determine whether the mobile device is a priority device that should be given priority in communication connection, The system includes a communication connection control unit (S210, S225, S227, S230, S234, S235, S240, S245, S247, S250) that controls the communication connection with the mobile device, The aforementioned communication unit has a defined upper limit on the number of mobile devices that can establish a communication connection at the same time. The aforementioned communication connection control unit, Based on the information acquired by the acquisition unit, the mobile device is determined to be the preferred device. A communication connection management system configured to, when it is already in communication with multiple of the above-mentioned mobile devices up to the connection limit, receive a connection request from a new mobile device, and if the new device is the preferred device, establish a communication connection with the new device without determining its priority among the multiple mobile devices that are already in communication, and disconnect the communication connection with the mobile device with the lowest priority among the other mobile devices that are already in communication.

17. A communication connection management system for managing communication connections between an object (Hv) and a plurality of portable devices (9), A communication unit (2) provided on the object and performing wireless communication with the portable device, An acquisition unit (S205) acquires information from the mobile device via wireless communication with the mobile device via the communication unit to determine whether the mobile device is a priority device that should be given priority in communication connection, A communication connection control unit (S210, S225, S227, S230, S234, S235, S240, S245, S247, S250) controls the communication connection with the aforementioned mobile device, The system includes a storage unit (14) that stores information of the mobile device with which the communication unit has established a communication connection, linked to a user ID indicating the user of the mobile device. The aforementioned communication unit has a defined upper limit on the number of mobile devices that can establish a communication connection at the same time. The aforementioned communication connection control unit, Based on the information acquired by the acquisition unit, the mobile device is determined to be the preferred device. When a communication connection is established with multiple of the above-mentioned mobile devices up to the connection limit, and a connection request is received from a new device which is a new mobile device, and the new device is the preferred device, the communication connection with one of the above-mentioned mobile devices up to the connection limit that is currently connected is terminated, and a communication connection is established with the new device. In a situation where multiple mobile devices are already connected to the maximum number of connections, if a connection request is received from a new device, and the new device is not the preferred device, the system is configured to determine a priority order for communication connections between the connected devices (which were already connected before receiving the connection request from the new device) and the new device, and to disconnect the communication connection of the mobile device with the lowest priority. The communication connection control unit is further configured to, in determining priority, verify whether there are any mobile devices among the connected devices and the new devices whose user IDs overlap with other mobile devices, and if there are mobile devices with overlapping user IDs, set the priority of the mobile devices with overlapping user IDs lower than the priority of mobile devices whose user IDs do not overlap with other mobile devices, in the communication connection management system.

18. A communication connection management system for managing communication connections between an object (Hv) and a plurality of portable devices (9), A communication unit (2) provided on the object and performing wireless communication with the portable device, An acquisition unit (S205) acquires information from the mobile device via wireless communication with the mobile device via the communication unit to determine whether the mobile device is a priority device that should be given priority in communication connection, The communication unit comprises a communication connection control unit (S210, S225, S227, S230, S234, S235, S240, S245, S247, S250) which performs processing to limit the number of simultaneous connections, which is the number of mobile devices connected to the communication unit at the same time, to a predetermined connection limit or less. The connection limit is a parameter introduced to suppress communication delays between the communication unit and the multiple mobile devices, The aforementioned communication connection control unit is configured to allow the number of simultaneous connections to temporarily exceed the connection limit. The aforementioned communication connection control unit further, Based on the information acquired by the acquisition unit, the mobile device is determined to be the preferred device. When a communication connection is established with multiple of the above-mentioned mobile devices up to the connection limit, and a connection request is received from a new device which is a new mobile device, and the new device is the preferred device, the communication connection with one of the above-mentioned mobile devices up to the connection limit that is currently connected is terminated, and a communication connection is established with the new device. In a situation where multiple mobile devices are already connected to the maximum number of connections, and a connection request is received from a new device, and the new device is not the preferred device, the connection to the already connected device (a mobile device that was already connected before receiving the connection request from the new device) is maintained while simultaneously establishing a communication connection with the new device. A communication connection management system configured to measure the distance between each of the connected mobile devices and the system when the number of simultaneous connections exceeds the connection limit, using Bluetooth Low Energy Channel Sounding (BLECS) communication, which transmits and receives a continuous wave signal whose frequency is periodically changed, and / or UWB communication, which transmits and receives an ultra-wideband (UWB) signal, and to determine which mobile device to disconnect based on the distance measurement results.

19. A communication connection management method, which is executed by a computer, for managing communication connections between an object (Hv) and multiple mobile devices (9), The object has a communication unit (2) that performs wireless communication with the portable device, The aforementioned communication unit has a defined upper limit on the number of mobile devices that can establish a communication connection at the same time. By wireless communication with the mobile device via the communication unit, information is obtained from the mobile device to determine whether the mobile device is a priority device that should be given priority in communication (S205), Based on the acquired information, determine whether the mobile device is the preferred device (S230), A communication connection management method comprising: when a communication connection is established with multiple of the above-mentioned mobile devices up to the maximum number of connections allowed, receiving a connection request from a new device which is a new mobile device, and if the new device is the preferred device, disconnecting the communication connection with one of the above-mentioned mobile devices up to the maximum number of connections allowed, and establishing a communication connection with the new device (S210, S225, S227, S234, S235, S240, S245, S247, S250).

20. A computer that performs processing to manage communication connections between an object (Hv) and multiple mobile devices (9), The object has a communication unit (2) that performs wireless communication with the portable device, The aforementioned communication unit has a defined upper limit on the number of mobile devices that can establish a communication connection at the same time. The aforementioned computer, The process (S205) involves obtaining information from the mobile device via wireless communication with the mobile device via the communication unit to determine whether the mobile device is a priority device that should be given priority in communication connection, A process (S230) to determine whether the mobile device is the preferred device based on the acquired information, A computer configured to perform the following steps (S210, S225, S227, S234, S235, S240, S245, S247, S250): When the computer is in communication with multiple of the above-mentioned mobile devices up to the maximum number of connections allowed, it receives a connection request from a new mobile device, and if the new device is the preferred device, it disconnects the communication connection with one of the above-mentioned mobile devices up to the maximum number of connections allowed, and establishes a communication connection with the new device.