Communication system and in-vehicle device

Abstract

To determine a transmission source of a signal with accuracy, in a communication system that includes a first communication device and a second communication device that perform wireless communication interactively.SOLUTION: An on-vehicle device 4 mounted on a vehicle is used as a first communication device in a communication system 1 that includes a first communication device 4 and a second communication device 2 that perform wireless communication interactively. The on-vehicle device 4 comprises a main antenna 51, at least one sub antenna 6, a first communication execution unit 55, and a determination unit 59. The determination unit determines that a transmission source of a communication frame received by the sub antenna is the second communication device when the communication frame includes second direction information being communication direction information and indicating that a communication direction is a second direction. The second communication device comprises a transmission / reception antenna 21 and a second communication execution unit 24.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to a communication system that performs bidirectional wireless communication. [Background technology]

[0002] There is known a technology that enables door locking and unlocking, engine starting, etc., in a vehicle when a portable device carried by a person approaches within a predetermined range from the vehicle. Whether or not the portable device approaches within a predetermined range from the vehicle is determined based on the strength of a signal received from the portable device. For example, the following Patent Document 1 proposes a technology in which, in order to detect the position of the portable device, a signal transmitted by wireless communication between a device mounted on the vehicle (hereinafter, referred to as a master device) and the portable device is also received by a monitor device mounted on the same vehicle. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 6711413 Summary of the Invention [Problem to be solved by the invention]

[0004] Between the master device and the mobile device described in the above-mentioned Patent Document 1, for example, two-way wireless communication is performed in accordance with the Bluetooth Low Energy (Bluetooth is a registered trademark) standard. In Bluetooth Low Energy (hereinafter, BLE), communication is repeated with a pair of a communication frame from a master device to a portable device and a communication frame from the portable device to the master device. In the pair of communication frames, first, the master device transmits a communication frame to the portable device, and then the portable device transmits a communication frame to the master device.

[0005] Here, for example, while communication is being performed between the master device and the mobile device, the monitoring device continuously overwrites and saves the strength of the received signal in memory. Since communication must be completed for each frequency hopping period in BLE, it is considered that if the monitoring device obtains the value written in memory at the end of this period, it can determine that the value is the reception strength of the signal originating from the mobile device.

[0006] However, while the above-mentioned communication from the portable device to the master device is being executed, a situation may occur in which the monitoring device does not receive the communication from the portable device to the master device (i.e., there is no received signal). In this case, there is a risk that the signal from the master device will be erroneously determined to be a signal from the portable device. In other words, there is a risk that the source of the signal will not be determined accurately.

[0007] One aspect of the present disclosure is to accurately determine a source of a signal in a communication system including a first communication device and a second communication device that perform bidirectional wireless communication. [Means for solving the problem]

[0008] One aspect of the present disclosure is an in-vehicle device (4) used as a first communication device in a communication system (1) including a first communication device (4) and a second communication device (2) that perform bidirectional wireless communication, and mounted on a vehicle. The in-vehicle device includes a main antenna (51), at least one sub-antenna (61), a first communication execution unit (53, 55), and a determination unit (63, 59). The main antenna is configured to transmit and receive signals. The sub-antenna is an antenna different from the main antenna, and is configured to receive signals.

[0009] The first communication execution unit is configured to generate first direction information, which is communication direction information indicating that the communication direction is a first direction, and to transmit a communication frame including the first direction information via the main antenna. The communication direction information indicates the communication direction of a communication frame included in a pair of communication frames for wireless communication, the pair being a communication frame transmitted in the first direction and a communication frame transmitted in the second direction. The first direction is a direction from the first communication device to the second communication device. The second direction is a direction from the second communication device to the first communication device.

[0010] The determination unit is configured to determine that the source of the communication frame is the second communication device when the communication frame received by the sub-antenna includes communication direction information that is second direction information indicating that the communication direction is the second direction.

[0011] The second communication device is configured to be portable. The second communication device includes a transmitting / receiving antenna (21) and a second communication execution unit (23, 24). The transmitting / receiving antenna is configured to transmit and receive a signal. The second communication execution unit is configured to generate second direction information and transmit a communication frame including the generated second direction information when a signal including the first direction information is received via the transmitting / receiving antenna.

[0012] One aspect of the present disclosure is a communication system (1) including a first communication device (4) and a second communication device (2) that perform bidirectional wireless communication. The first communication device includes a main antenna (51), at least one sub-antenna (61), a first communication execution unit (53, 55), and a determination unit (63, 59). The main antenna is configured to transmit and receive signals. The sub-antenna is an antenna different from the main antenna and is configured to receive signals.

[0013] The first communication execution unit is configured to generate first direction information, which is communication direction information indicating that the communication direction is a first direction, and to transmit a communication frame including the first direction information via the main antenna. The communication direction information indicates the communication direction of a communication frame included in a pair of communication frames for wireless communication, the pair being a communication frame transmitted in the first direction and a communication frame transmitted in the second direction. The first direction is a direction from the first communication device to the second communication device. The second direction is a direction from the second communication device to the first communication device.

[0014] The determination unit is configured to determine that the source of the communication frame is the second communication device when the communication frame received by the sub-antenna includes communication direction information that is second direction information indicating that the communication direction is the second direction.

[0015] The second communication device is configured to be portable. The second communication device includes a transmitting / receiving antenna (21) and a second communication execution unit (23, 24). The transmitting / receiving antenna is configured to transmit and receive a signal. The second communication execution unit is configured to generate second direction information and transmit a communication frame including the generated second direction information when a signal including the first direction information is received via the transmitting / receiving antenna.

[0016] According to this configuration, when the second direction information is included in the received communication frame, the first communication device determines that the transmission source of the received signal is the second communication device. Therefore, for example, it is possible to identify the signal originating from the second communication device more accurately than when the strength of the received signal acquired at a pre-estimated timing (for example, the end of the frequency hopping period) is always determined to be the strength of the signal originating from the second communication device.

[0017] As a result, in a communication system including a first communication device and a second communication device that perform bidirectional wireless communication, the source of a signal can be determined with high accuracy. [Brief description of the drawings]

[0018] [Figure 1] FIG. 1 is a block diagram showing a configuration of a communication system. [Diagram 2] This is an explanatory diagram explaining the function of the smart entry start system. [Diagram 3] FIG. 2 is a block diagram showing a configuration of an in-vehicle control unit. [Figure 4] FIG. 2 is a block diagram showing a configuration of a monitor control unit. [Diagram 5] 4 is a block diagram showing a configuration of a mobile control unit. FIG. [Figure 6] FIG. 1 is an explanatory diagram illustrating BLE communication. [Figure 7] FIG. 2 is an explanatory diagram for explaining a communication frame. [Figure 8] FIG. 2 is an explanatory diagram for explaining frame division. [Figure 9] 4 is a flowchart of an in-vehicle communication process. [Figure 10] 13 is a flowchart (1 / 2) of BLE communication processing in the in-vehicle device. [Figure 11] 13 is a flowchart (2 / 2) of BLE communication processing in the in-vehicle device. [Figure 12] 13 is a flowchart of a transmission source determination process. [Figure 13] 13 is a flowchart of a position identification process. [Figure 14] 13 is a flowchart of a mobile communication process. [Figure 15] 13 is a flowchart of BLE communication processing in a smart device. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. [1. Configuration] <Overall composition> The communication system 1 shown in Fig. 1 includes an in-vehicle device 4 mounted on a vehicle 3, and a portable smart device 2. The in-vehicle device 4 and the smart device 2 perform two-way wireless communication in accordance with the Bluetooth Low Energy (hereinafter, referred to as BLE) standard, with the in-vehicle device 4 acting as a master device and the smart device 2 acting as a slave device. Bluetooth is a registered trademark.

[0020] 2, the in-vehicle device 4 has a function (i.e., a so-called smart entry / start system function) that enables door locking and unlocking, engine starting and stopping, etc., when the smart device 2 carried by a person approaches within a predetermined range of the vehicle 3. Whether or not the smart device 2 has approached within the predetermined range of the vehicle 3 (i.e., the position of the smart device 2) is determined based on the strength of a signal received by BLE communication from the smart device 2. BLE communication refers to communication in accordance with a method compliant with BLE.

[0021] [1-1.In-vehicle device] 1, the in-vehicle device 4 includes a main antenna 51 and an in-vehicle control unit 53. The in-vehicle device 4 may also include an in-vehicle transceiver 52 and a target device 7. The in-vehicle control unit 53 is an ECU. ECU stands for Electronic Control Unit. For example, as shown in FIG. 2, the in-vehicle communication unit 5 including the main antenna 51, the in-vehicle transceiver 52, and the in-vehicle control unit 53 may be installed in a C-pillar behind the rear seats.

[0022] The main antenna 51 is an antenna for transmitting and receiving signals (i.e., radio waves) in the 2.4 GHz band used in BLE communication. The in-vehicle transceiver 52 demodulates the signal received via the main antenna 51 and outputs the demodulated signal to the in-vehicle control unit 53. The in-vehicle transceiver 52 also modulates the signal output from the in-vehicle control unit 53 and transmits the modulated signal via the main antenna 51.

[0023] The in-vehicle device 4 also includes at least one sub-antenna 61 and at least one monitor control unit 63. The in-vehicle device 4 may also include at least one monitor receiver 62. In this embodiment, the in-vehicle device 4 includes a plurality of (e.g., four) sub-antennas 61 (i.e., 61a, 61b, 61c, 61d) and a plurality of (e.g., four) monitor control units 63 (i.e., 63a, 63b, 63c, 63d) as shown in Figs. 1 and 2. The in-vehicle device 4 also includes a plurality of (e.g., four) monitor receivers 62 (i.e., 62a, 62b, 62c, 62d).

[0024] In the following description, when describing a common description of individual components such as the sub-antenna 61a, the sub-antenna 61b, etc., the subscript will be omitted, for example, to describe the components as the sub-antenna 61.

[0025] The sub-antenna 61 is an antenna for receiving a signal (i.e., radio wave) in the 2.4 GHz band used for BLE communication. For example, as shown in Fig. 2, the sub-antenna 61a is arranged inside the vehicle cabin, the sub-antenna 61b is arranged near the door lock of the right door, the sub-antenna 61c is arranged near the door lock of the left door, and the sub-antenna 61d is arranged near the door lock of the rear door.

[0026] Each of the sub-antennas 61a, 61b, 61c, and 61d is connected to one monitor receiver 62 (i.e., 63a, 63b, 63c, and 63d). Each of the monitor receivers 62 is connected to one monitor control unit 63 (i.e., 62a, 62b, 62c, and 62d). The monitor device 6 referred to below includes one sub-antenna 61, one monitor receiver 62, and one monitor control unit 63. In other words, the in-vehicle device 4 includes a plurality of (i.e., four) monitor devices 6 (i.e., 6a, 6b, 6c, and 6d).

[0027] The number of monitor devices 6 included in the in-vehicle device 4 of this embodiment is not limited to four. The number of monitor devices 6 included in the vehicle 3 may be two, three, five or more as long as it is more than one.

[0028] <On-board control unit> As shown in FIG. 3, the in-vehicle control unit 53 is an electronic control device mainly configured with a microcomputer including a CPU 530 and a memory 531 such as a ROM and a RAM. Various functions of the microcomputer are realized by the CPU 530 executing a program stored in a non-transient real recording medium. In this example, the ROM corresponds to the non-transient real recording medium storing the program. Furthermore, the execution of this program executes a method corresponding to the program. Note that some or all of the functions executed by the CPU 530 may be configured in hardware using one or more ICs or the like. Furthermore, the number of microcomputers constituting the in-vehicle control unit 53 may be one or more.

[0029] As shown in FIG. 1, the in-vehicle control unit 53 has functions as a BLE communication unit 55, a communication control unit 56, a target driving unit 57, and a position identification unit 58. The BLE communication unit 55 performs short-distance wireless communication in a BLE-compliant manner with the smart device 2 via the main antenna 51 and the in-vehicle transceiver 52. The BLE communication unit 55 executes in-vehicle communication processing, which will be described later.

[0030] In BLE communication, so-called frequency hopping technology is applied. For example, communication is performed by changing a predetermined number of channels (for example, 5 channels) among multiple channels (for example, 37 channels) obtained by dividing the 2.4 GHz frequency band into 2 MHz widths based on information (hereinafter, frequency information) determined when a connection is established. Frequency information refers to information indicating the above-mentioned predetermined number of channels.

[0031] Based on the frequency information, the in-car device 4 and the smart device 2 transmit and receive signals to and from each other on the same channel. The channel is switched to the next channel after a predetermined interval period Ti has elapsed since the in-car device 4 started transmitting a communication frame. In other words, in BLE communication, communication is completed every frequency hopping period (i.e., every interval period Ti).

[0032] The above-mentioned in-vehicle transceiver 52 generates a transmission signal for the smart device 2 by modulating a transmission carrier wave of a channel based on the above-mentioned frequency information for a signal indicating a communication frame output from the BLE communication unit 55, and transmits the signal from the main antenna 51. The in-vehicle transceiver 52 also changes the passband of a frequency filter based on the above-mentioned frequency information, for example, and receives a signal of the channel transmitted from the smart device 2.

[0033] Furthermore, the in-vehicle transceiver 52, for example, demodulates a signal indicating a communication frame from the received signal, generates data indicating the communication frame, and inputs the data to the BLE communication unit 55. Note that the in-vehicle transceiver 52 may have a function of restoring data indicating the communication frame before encryption from data indicating the encrypted communication frame.

[0034] The communication control unit 56 performs control related to BLE communication, that is, more specifically, control related to a communication frame to be transmitted to the smart device 2. For example, the communication control unit 56 determines whether or not data included in a communication frame is to be transmitted by frame division (described later) and notifies the BLE communication unit 55 of the presence or absence of frame-divided data to be transmitted.

[0035] The target driving unit 57 drives the target apparatus 7 when the smart device 2 approaches within a predetermined range from the vehicle 3. For example, as shown in Fig. 2, the target driving unit 57 determines whether the position of the smart device 2 identified by the position identifying unit 58 is inside the vehicle cabin (e.g., within the area Aa). When it is determined that the position of the smart device 2 is inside the vehicle cabin, the target driving unit 57 starts or stops the engine of the vehicle 3 as the target apparatus 7 when there is an instruction from the smart device 2 (i.e., according to the instruction).

[0036] In addition, the target driving unit 57 determines whether the position of the smart device 2 identified by the position identifying unit 58 is near the right door (for example, within the area Ab). When the target driving unit 57 determines that the position of the smart device 2 is near the right door, it unlocks or locks the door lock of the right door as the target device 7 upon receiving an instruction from the smart device 2.

[0037] Similarly, the in-vehicle device 4 determines whether the position of the smart device 2 identified by the position identification unit 58 is near the left door (for example, within the area Ac). When the position of the smart device 2 is determined to be near the left door, the target drive unit 57 unlocks or locks the door lock of the left door as the target device 7 upon receiving an instruction from the smart device 2.

[0038] Similarly, the in-vehicle device 4 determines whether the position of the smart device 2 identified by the position identification unit 58 is near the rear door (for example, within the area Ad). When it is determined that the position of the smart device 2 is near the rear door, the target drive unit 57 unlocks or locks the door lock of the rear door as the target device 7 upon receiving an instruction from the smart device 2.

[0039] The position identifying unit 58 identifies the position of the smart device 2 based on the reception strength signal of the reception signal from the smart device 2 input from each monitor device 6 (i.e., specifically, the determination unit 59). The position identifying unit 58 executes a position identifying process, which will be described later.

[0040] <Monitor device> As described above, the sub-antenna 61 is an antenna for receiving a signal in the 2.4 GHz band used in the BLE communication. Therefore, a signal by the BLE communication between the in-vehicle device 4 (specifically, the BLE communication unit 55) and the smart device 2 is also received by each of the sub-antennas 61 (i.e., 61a, 61b, 61c, and 61d) mounted on the vehicle 3.

[0041] In other words, if the above-mentioned frequency information is known, the signal by the BLE communication between the in-car device 4 and the smart device 2 can be received by the monitoring device 6 (i.e., the sub-antenna 61, the monitoring receiver 62, and the monitoring control unit 63). Receivable means, in other words, that the signal can be intercepted.

[0042] The monitor receiver 62 changes the passband of a frequency filter based on, for example, the above-mentioned frequency information, receives a signal of a channel transmitted from the smart device 2, and demodulates the received signal into a signal indicating a communication frame. The monitor control unit 63 generates data indicating the communication frame from the signal indicating the communication frame and outputs the data to the monitor control unit 63. The data here may be, for example, data expressed in binary.

[0043] The frequency information may be output from the in-vehicle control unit 53 (e.g., the BLE communication unit 55) to the monitor device 6 (e.g., the monitor receiver 62 and the monitor control unit 63) when a connection is established between the in-vehicle device 4 and the smart device 2. The monitor receiver 62 is configured to change the passband of the frequency filter for each interval period Ti, for example, based on the frequency information. The start timing of the interval period Ti may be notified from the in-vehicle control unit 53 (e.g., the BLE communication unit 55) to the monitor control unit 63 and the monitor receiver 62.

[0044] Furthermore, the monitor receiver 62 detects the strength of the received signal received via the sub-antenna 61. Specifically, the monitor receiver 62 generates a reception strength signal that represents the strength of the received signal as an analog signal such as a voltage value, and outputs the reception strength signal indicating the reception strength to the monitor control unit 63 (i.e., the determination unit 59).

[0045] <Monitor control section> As shown in FIG. 4, the monitor control unit 63 is an electronic control device mainly configured with a microcomputer including a CPU 630 and a memory 631 such as a ROM and a RAM, similar to the above-mentioned in-vehicle control unit 53. Various functions of the microcomputer are realized by the CPU 630 executing a program stored in a non-transient real recording medium. In this example, the ROM corresponds to the non-transient real recording medium storing the program. Furthermore, the execution of this program executes a method corresponding to the program. Note that some or all of the functions executed by the CPU 630 may be configured in hardware form using one or more ICs, etc. Also, the number of microcomputers constituting the monitor control unit 63 may be one or more.

[0046] 1, the monitor control unit 63 has a function as a determination unit 59. The determination unit 59 executes a transmission source determination process described later. The determination unit 59 identifies a signal whose transmission source is the smart device 2 among the signals received via the sub-antenna 61. Then, the determination unit 59 inputs a reception strength signal indicating the reception strength of the identified signal whose transmission source is the smart device 2 to the in-vehicle control unit 53 (i.e., the position identification unit 58).

[0047] In this embodiment, the monitor control unit 63 acquires a reception intensity signal from the monitor receiver 62 at predetermined intervals, and stores the reception intensity signal (i.e., the reception intensity indicated by the reception intensity signal) in the memory 631. The monitor control unit 63 may, for example, overwrite the memory 631 and store the signal every time it acquires a reception intensity signal.

[0048] [1-2. Smart devices] The smart device 2 is configured to be portable (i.e., to be carried by a person). The smart device 2 may be, for example, a so-called smartphone. The smart device 2 executes an app for a smart entry / start system. While executing the app, the smart device 2 outputs an instruction to the in-vehicle device 4 through BLE communication based on an input operation by a user when the smart device 2 is located within a predetermined range from the vehicle 3 (i.e., the sub-antenna 61 installed in the vehicle 3).

[0049] The instructions include instructions to lock and unlock each door of the vehicle 3, start and stop the engine, etc. As a result, in the vehicle 3, the lock and unlock of each door, start and stop of the engine, etc. are executed according to the instructions of the smart device 2 as described above.

[0050] The smart device 2 includes a mobile antenna 21, a mobile transceiver 22, and a mobile control unit 23. The mobile antenna 21 is an antenna for receiving a signal in the 2.4 GHz band used in BLE communication. The mobile transceiver 22 is configured in the same manner as the above-mentioned in-vehicle transceiver 52. That is, the mobile transceiver 22 generates a transmission signal to the in-vehicle device 4 by modulating a transmission carrier wave of a channel based on frequency information for a signal indicating a communication frame of BLE communication, and transmits the signal from the mobile antenna 21.

[0051] In addition, the portable transceiver 22 changes the passband of a frequency filter based on, for example, frequency information, receives a signal of a channel transmitted from the vehicle-mounted device 4, demodulates the received signal, and inputs data indicating a communication frame to the portable control unit 23.

[0052] The mobile control unit 23 is an electronic control device mainly composed of a microcomputer including a CPU 230, a memory 231 such as a ROM and a RAM, as shown in FIG. 5, similar to the above-mentioned in-vehicle control unit 53 and monitor control unit 63. Various functions of the microcomputer are realized by the CPU 230 executing a program stored in a non-transitive substantial recording medium. In this example, the ROM corresponds to the non-transitive substantial recording medium storing the program. Furthermore, the execution of this program executes a method corresponding to the program. Note that some or all of the functions executed by the CPU 230 may be configured in hardware form using one or more ICs, etc. Also, the number of microcomputers constituting the mobile control unit 23 may be one or more. For example, the program of the above-mentioned application is stored in the memory 231.

[0053] As shown in Fig. 1, the mobile control unit 23 has a function as a communication unit 24. The communication unit 24 executes mobile communication processing, which will be described later. As shown in Fig. 1, the communication unit 24 performs short-range wireless communication with the in-vehicle device 4 via the mobile antenna 21 and the mobile transceiver 22 in a method conforming to BLE.

[0054] [1-3. Smart device location] <About location estimation> In BLE communication, after a connection is established, communication is repeated with a pair (hereinafter, referred to as paired frames) of a communication frame from the in-vehicle device 4 to the smart device 2 and a communication frame from the smart device 2 to the in-vehicle device 4. Note that the communication frame referred to here refers to a communication frame indicating a data packet.

[0055] In the pair frame, first, a communication frame is transmitted from the in-vehicle device 4 to the smart device 2, and then, a communication frame is transmitted from the smart device 2 to the in-vehicle device 4. For example, in Fig. 6, the communication frames surrounded by the dotted line, i.e., the communication frame from the in-vehicle device 4 to the smart device 2 indicated by the white arrow, and the communication frame from the smart device 2 to the in-vehicle device 4 indicated by the black arrow, correspond to one pair frame.

[0056] As described above, in BLE communication, communication is performed by a frequency hopping method. For example, communication is performed using the same frequency (i.e., the same channel) from when the in-vehicle device 4 starts transmitting a communication frame until a predetermined interval period Ti has elapsed. Next, communication is performed using a different next channel from when the in-vehicle device 4 starts transmitting a communication frame until an interval period Ti has elapsed.

[0057] Since the interval period Ti is determined, it is possible to estimate the timing at which the in-vehicle device 4 receives a communication frame from the smart device 2 while communication is being performed between the in-vehicle device 4 and the smart device 2. The signal received by the sub-antenna 61 at this timing is estimated to be a signal from the smart device 2. For example, it is considered possible to estimate the position of the smart device 2 based on the reception strength of this signal (i.e., the reception strength stored in the memory 631 by the monitor receiver 62 at this timing). This is so-called position detection based on RSSI (i.e., the strength of the signal received from the smart device 2). RSSI is an abbreviation for Received Signal Strength Indicator.

[0058] A predicted period Tp during which communication by the paired frames is assumed to be performed within the interval period Ti is assumed in advance. For example, the reception strength stored in the memory 631 by the determination unit 59 at the timing P closest to the end of the predicted period Tp is assumed to be the reception strength of a signal transmitted from the smart device 2. This makes it possible to estimate the signal transmitted from the smart device 2 and detect the position of the smart device 2 based on the reception strength of the signal.

[0059] However, while communication from the smart device 2 to the in-vehicle device 4 is being executed, for example, a situation may occur in which a signal transmitted from the smart device 2 is not received (i.e., a situation in which there is no received signal). Examples of situations in which there is no received signal include a situation in which a metal product that affects the performance of the sub-antenna 61 is placed near the sub-antenna 61, the sub-antenna 61 is covered by a metal product, or a situation in which a malfunction of the sub-antenna 61 occurs.

[0060] In this case, the reception strength (i.e., the reception strength indicating some kind of signal) stored in memory 631 at the timing P closest to the end of the prediction period Tp may not be the reception strength of a signal transmitted from the smart device 2, but rather the reception strength of the immediately preceding signal transmitted from the in-vehicle device 4.

[0061] In other words, the signal detected by the determination unit 59 at the timing P closest to the end of the prediction period Tp is not necessarily a signal whose source is the smart device 2. If such a detection result is used, there is a risk that the signal may be erroneously determined to be from the smart device 2 even though it is actually from the in-vehicle device 4, and as a result, the position of the smart device 2 may be erroneously detected.

[0062] <Identifying the source of the received signal> Therefore, the in-vehicle device 4 identifies the transmission source of the communication frame as follows. As shown in FIG. 6, in BLE communication, communication regarding one pair of frames described above is called one sequence. In other words, one sequence includes one communication frame transmitted in a first direction and one communication frame transmitted in a second direction. The first direction is the direction from the in-vehicle device 4 to the smart device 2, and the second direction is the direction from the smart device 2 to the in-vehicle device 4.

[0063] In BLE communication, a number (hereinafter, sequence number) is assigned to each sequence to distinguish between the sequences (i.e., each pair of frames). For example, two numerical values, 0 and 1, each represented by one bit, are used as sequence numbers. The sequence numbers are assigned in order, for example, 0, 1, 0, 1, ..., with each sequence number being repeated for each sequence number (for example, 0 and 1 in this case, so two). In other words, at least in consecutive sequences, different sequence numbers are assigned.

[0064] In a communication frame of BLE communication (i.e., a communication frame of a data packet), the Header (hereinafter, referred to as "header") section includes NESN and SN, as shown in Fig. 7. NESN and SN are each represented by 1 bit. Here, SN indicates the sequence (i.e., paired frame) that includes the communication frame to be transmitted. Meanwhile, NESN indicates the sequence (i.e., paired frame) that includes the communication frame to be received next.

[0065] In other words, the SN is information indicating a pair frame including a communication frame to be transmitted (hereinafter also referred to as current pair frame information). The NESN is information indicating a pair frame including a communication frame to be received next (hereinafter also referred to as next pair frame information). Hereinafter, the SN and NESN are also referred to as communication direction information.

[0066] The communication direction information is information indicating the communication direction of a communication frame included in a pair frame. The communication direction of a communication frame refers to the direction from where the communication frame is transmitted to where. As described above, one pair frame includes one communication frame transmitted in a first direction and one communication frame transmitted in a second direction. It can be said that the communication direction information includes the SN as the current pair frame information and the NESN as the next pair frame information.

[0067] 6, the communication frame transmitted in the first direction from the in-vehicle device 4 always has NESN=SN, and the communication frame transmitted in the second direction from the smart device 2 always has NESN≠SN. In this way, the transmission direction of the communication frame is specified as the first direction or the second direction depending on the combination of NESN and NS (i.e., whether NESN=SN or NESN≠SN).

[0068] Therefore, in the communication system 1, the sender of the communication frame is identified based on the difference in the combination of the NESN and NS between the communication frame transmitted in the first direction and the communication frame transmitted in the second direction. Hereinafter, the communication direction information indicating the first direction (i.e., NESN and SN where NESN=NS) is also referred to as first direction information. Also, the communication direction information indicating the second direction (i.e., NESN and SN where NESN≠NS) is also referred to as second direction information.

[0069] In addition, in a communication frame of BLE communication, the header portion is a portion that is not encrypted (hereinafter, referred to as a non-encrypted portion). In other words, the communication direction information is included in the non-encrypted portion of the communication frame. <About frame division> The upper limit of the amount of data that can be transmitted by one communication frame is determined in advance. In BLE communication, when transmitting data that exceeds the upper limit of the data amount, frame division is performed. In frame division, when transmitting data that exceeds the upper limit, the transmitting device divides the data to be transmitted into multiple pieces of data that are equal to or smaller than the upper limit, and transmits multiple communication frames including the divided data.

[0070] For example, assume that the amount of data transmitted from the in-vehicle device 4 exceeds the upper limit value, and the data is divided into multiple pieces (e.g., three pieces) and transmitted. In this case, as shown in "Frame Division" in Fig. 8, three first-direction communication frames are transmitted within an interval period Ti, and corresponding to each of the first-direction communication frames, a second-direction communication frame is transmitted from the smart device 2. That is, communication is performed using three paired frames L1-L3.

[0071] Frame division is also performed in the same manner when the amount of data transmitted from the smart device 2 exceeds the upper limit value. Communication based on frame division is performed so as to be completed within the interval period Ti.

[0072] Even when a frame is divided, the header section contains the same NESN and NS as described above. That is, even when a frame is divided, the communication direction of the communication frame, and therefore the source of the communication frame, are identified based on the combination of NESN and NS, as described above.

[0073] The MD included in the header is 1-bit information, and when it is 1, it indicates that the source device has a frame to send next, and when it is 0, it indicates that the source device has no communication frame to send next. In other words, under normal circumstances when frame division is not performed, MD = 0. When frame division is performed and there is a communication frame to send next, MD = 1.

[0074] [2. Processing] [2-1. Processing performed by the in-vehicle device] The process executed by the in-vehicle device 4 will be described with reference to the flowcharts of FIGS.

[0075] <In-vehicle communication processing> 9 to 11, a description will be given of an in-vehicle communication process executed by the in-vehicle control unit 53 (specifically, the BLE communication unit 55) of the in-vehicle device 4. The in-vehicle communication process may be executed repeatedly (for example, constantly).

[0076] In S10, the BLE communication unit 55 transmits an iBeacon (registered trademark) including vehicle information capable of identifying the vehicle 3. The vehicle information may be, for example, information capable of identifying an individual vehicle (i.e., a vehicle ID). As described later, when the smart device 2 receives an iBeacon including a registered vehicle ID, the smart device 2 transmits an advertisement packet including a mobile ID capable of identifying the smart device 2.

[0077] In the next step S20, the BLE communication unit 55 starts scanning for advertisements. That is, the BLE communication unit 55 starts receiving advertisement packets via the main antenna 51 and the in-vehicle transceiver 52.

[0078] Next, in S30, the BLE communication unit 55 determines whether or not an advertisement packet including a mobile ID (hereinafter, also referred to as a target advertisement packet) is detected. The mobile ID is information capable of identifying a smart device (i.e., a smart device 2) that is registered in advance (i.e., that is linked to the vehicle 3 in advance). That is, the BLE communication unit 55 determines whether or not a mobile ID is stored in an advertisement packet received via the main antenna 51 and the in-vehicle transceiver 52. Here, if the target advertisement packet is not detected, the BLE communication unit 55 waits until the target advertisement packet is detected by repeating the process of S30. On the other hand, when the BLE communication unit 55 detects the target advertisement packet, the process proceeds to S40.

[0079] In S40, the BLE communication unit 55 transmits a connection request to the smart device 2 that transmitted the target advertising packet. In the next step S50, the BLE communication unit 55 performs pairing with the smart device 2 that sent the target advertising packet in accordance with the BLE standard specifications, and after pairing is completed, establishes a short-range wireless communication connection using a method compliant with BLE.

[0080] Next, in S60, the BLE communication unit 55 executes BLE communication with the smart device 2 with which the connection has been established. The BLE communication here refers to transmission and reception of data packets. The BLE communication process executed by the BLE communication unit 55 will be described later.

[0081] In the next step S70, the BLE communication unit 55 determines whether or not there has been an end operation to end the BLE communication with the smart device 2 with which the connection has been established. Examples of the end operation include an operation in which the smart device 2 with which the connection has been established turns off the BLE communication, and an operation in which the smart device 2 ends an app (i.e., the app of the smart entry / start system). Another example of the end operation is when the smart device 2 moves out of the connection range.

[0082] Here, if it is determined that no termination operation has been performed, the BLE communication unit 55 returns the process to S60 and continues the BLE communication with the smart device 2 with which the connection has been established. On the other hand, if it is determined that a termination operation has been performed, the BLE communication unit 55 ends the in-vehicle communication process.

[0083] <BLE communication processing in in-vehicle equipment> Next, the BLE communication process executed by the in-vehicle control unit 53 (that is, the BLE communication unit 55) in S60 will be described with reference to FIGS.

[0084] The BLE communication unit 55 performs initial settings in S100-S110. For example, in S100, the BLE communication unit 55 sets an initial value of NESN (hereinafter also referred to as initial value NESN) and an initial value of SN (hereinafter also referred to as initial value SN). Also, it sets the maximum value that NESN and SN can take (hereinafter referred to as MAX value). In BLE communication, the initial values ​​of NESN and SN are 0, and the MAX value is 1. The respective initial values ​​and MAX values ​​may be stored in the memory 531 in advance.

[0085] In the next step S105, the BLE communication unit 55 sets the value of the master NESN to the initial value NESN (i.e., 0), and sets the value of the master SN to the initial value SN (i.e., 0). The master NESN is a value set as the NESN included in a communication frame whose source is the in-vehicle device 4, and the master SN is a value set as the SN included in a communication frame whose source is the in-vehicle device 4.

[0086] Next, in S110, the BLE communication unit 55 starts a timer for counting the interval period Ti. In S115-S130, the BLE communication unit 55 sets the NESN, SN, and MD included in the header of the communication frame in accordance with the BLE standard specifications.

[0087] For example, in S115, the BLE communication unit 55 sets the value of the master NESN as the NESN included in the communication frame whose source is the in-vehicle device 4, and sets the value of the master SN as the SN included in the communication frame whose source is the in-vehicle device 4.

[0088] In S120, the BLE communication unit 55 determines whether or not further continuous transmission will be performed from the in-vehicle device 4 during this interval period Ti (i.e., the same channel). Here, for example, if data is not transmitted by frame division, it is determined that further continuous transmission will not be performed. Also, for example, if data is transmitted by frame division and the last data of all the divided data is transmitted, it is determined that further continuous transmission will not be performed.

[0089] On the other hand, for example, when data is transmitted by frame division and the data transmitted is not the last data among all the divided data, it is determined that further continuous transmission will be performed. Note that whether or not to execute frame division and what number of data is currently transmitted among the data divided by frame division (i.e., whether or not it is the last data) may be determined by, for example, the communication control unit 56. Then, based on the result of the determination by the communication control unit 56, it may be determined whether or not further continuous transmission will be performed.

[0090] If it is determined that no further consecutive transmissions will be performed, the BLE communication unit 55 shifts the process to S125, sets MD to 0 in S125, and shifts the process to S135. If it is determined that further consecutive transmissions will be performed, the BLE communication unit 55 shifts the process to S130, sets MD to 1 in S130, and shifts the process to S135.

[0091] In S135, the BLE communication unit 55 sets the header other than the NESN, SN, and MD in accordance with the BLE standard specifications, generates a communication frame, and transmits the generated communication frame via the main antenna 51 and the vehicle-mounted transceiver 52.

[0092] The communication frame transmitted from the in-vehicle device 4 in this manner is a communication frame including the first direction information. The first direction information is communication direction information indicating that the communication direction is the first direction. Specifically, the above-mentioned NESN and SN, which are a combination of the same values, correspond to the first direction information. In other words, the BLE communication unit 55 generates, as the first direction information, communication direction information in which the current pair frame information and the next pair frame information are equal to each other.

[0093] Next, in S140, the BLE communication unit 55 stores the communication direction information (i.e., NESN, SN) and MD transmitted in S135 in the memory 531, for example. In the next step S145, the BLE communication unit 55 determines whether or not any signal has been received. If no signal has been received, the BLE communication unit 55 waits until any signal is received by repeating the process of S145. For example, the BLE communication unit 55 determines that any signal has been received when the reception strength of a signal received via the main antenna 51 is equal to or greater than a predetermined signal threshold.

[0094] The signal threshold may be set to a value that is, for example, greater than the strength of a signal received from a smart device 2 located in an unconnected area shown in Fig. 2 and less than the strength of a signal received from a smart device 2 located in a connected area shown in Fig. 2. The in-vehicle transceiver 52 may be configured to detect the reception strength of a signal received via the main antenna 51.

[0095] Next, in S150, the BLE communication unit 55 determines whether or not the communication frame originating from the smart device 2 has been normally received. For example, the BLE communication unit 55 may determine that the communication frame originating from the smart device 2 has been received when the Access Address (hereinafter, the access address) of the received communication frame matches the access address determined when the connection was established. The access address is included in the non-encrypted portion of the communication frame.

[0096] Here, normal reception means reception without error and without a retransmission request. For example, the BLE communication unit 55 may determine that a communication frame has been received without error when a CRC included in the received communication frame matches a CRC calculated based on the contents of the received communication frame. The BLE communication unit 55 may also determine that a retransmission request has not been made when a received communication frame (e.g., a payload, etc.) does not include a retransmission request for requesting retransmission of a transmitted communication frame.

[0097] If the BLE communication unit 55 determines that the communication frame transmitted from the smart device 2 has not been received normally, the BLE communication unit 55 shifts the process to S115 and repeats the process from S115 onwards. That is, the BLE communication unit 55 retransmits a communication frame similar to the communication frame transmitted immediately before. If the BLE communication unit 55 determines that the communication frame transmitted from the smart device 2 has been received normally, the BLE communication unit 55 shifts the process to S155.

[0098] In S155, the BLE communication unit 55 stores in the memory 531 the NESN, SN, and MD contained in the communication frame transmitted from the smart device 2 and received in S150. Next, in S160, the BLE communication unit 55 determines whether or not MD included in the header of the communication frame received from or transmitted from the smart device 2 is 0, based on the contents stored in the memory 531. If it is determined that MD is 0, the BLE communication unit 55 shifts the process to S180, and if it is determined that MD is 1, the BLE communication unit 55 shifts the process to S165.

[0099] In S165, the BLE communication unit 55 determines whether or not the value of the master NESN+1, that is, the NESN of the communication frame to be transmitted next from the in-vehicle device 4, is greater than the MAX value. Here, when it is determined that the value of the master NESN+1 is equal to or less than the MAX value, the BLE communication unit 55 shifts the process to S170. In S170, the BLE communication unit 55 sets the master NESN+1 as the new master NESN value, and sets the master SN+1 as the new master SN value. Then, the BLE communication unit 55 shifts the process to S115. As a result, in S115, NESN=1 and SN=1 are set.

[0100] On the other hand, when it is determined that the value of the master NESN+1 is greater than the MAX value, the BLE communication unit 55 shifts the process to S175. In S175, the BLE communication unit 55 initializes the values ​​of the master NESN and the master SN. That is, the master NESN is set to the initial value NESN (i.e., 0), and the master SN is set to the initial value SN (i.e., 0). Then, the BLE communication unit 55 shifts the process to S115. As a result, in S115, NESN=0 and SN=0 are set.

[0101] In S180, the BLE communication unit 55 waits until the count value of a timer for counting the interval period Ti reaches the interval period Ti. The interval period Ti may be, for example, several tens to several hundreds of msec.

[0102] In the next step S185, the BLE communication unit 55 stops the timer for counting the interval period Ti. Then, the BLE communication unit 55 ends this BLE communication process.

[0103] <Sender identification process> Next, the source determination process executed by each monitor control unit 63 (that is, each determination unit 59 in the monitor control unit 63) will be described with reference to the flowchart of FIG.

[0104] The determination unit 59 repeatedly executes this source determination process at predetermined intervals. First, in S200, the determination unit 59 acquires the reception strength of the reception signal output from the monitor receiver 62 and received via the sub-antenna 61 (that is, specifically, the reception strength signal).

[0105] Next, in S210, the determination unit 59 acquires data indicating the header portion from the data output from the monitor receiver 62 and indicating the communication frame. Next, in S220, the determination unit 59 determines whether the transmission source of the communication frame received by the sub-antenna 61 is the smart device 2. When the communication frame received by the sub-antenna 61 includes second direction information which is communication direction information and indicates that the communication direction is the second direction, the determination unit 59 determines that the transmission source of the communication frame is the smart device 2.

[0106] Specifically, the determination unit 59 determines whether the NESN and SN included in the header are different from each other (i.e., NESN ≠ SN). In this embodiment, being different from each other (i.e., not matching) means that NESN=1 and SN=0, or NESN=0 and SN=1.

[0107] Here, if the NESN and SN included in the header portion are different from each other, the determination unit 59 determines that the source of the communication frame is the smart device 2, proceeds to S230, and stores the reception intensity signal acquired in S200 in the memory 631. The determination unit 59 may overwrite and store the reception intensity signal in the memory 631. Then, the determination unit 59 outputs the reception intensity signal acquired in S200 to the position identification unit 58, and this ends the source determination process.

[0108] On the other hand, if the NESN and SN included in the header part match each other, the determination unit 59 determines that the sender of the communication frame is not the smart device 2 (i.e., the sender is the in-vehicle device 4), and proceeds to S240. In this embodiment, matching each other means that NESN=0 and SN=0, or NESN=1 and SN=1.

[0109] In S240, the determination unit 59 discards the reception intensity signal acquired in S200. That is, the determination unit 59 stores the reception intensity signal acquired in S200 in the memory 631, and does not output it to the position identification unit 58. The determination unit 59 may overwrite and store the reception intensity signal in the memory 631. With this, the determination unit 59 ends this transmission source determination process.

[0110] <Location Identification Processing> Next, the location identification process executed by the in-vehicle control unit 53 (that is, the location identification unit 58) will be described with reference to the flowchart of FIG.

[0111] The position identification unit 58 starts the position identification process when the determination unit 59 determines that the source of the communication frame received by the sub-antenna 61 is the smart device 2. For example, the above-mentioned determination unit 59 may be configured to set a flag when it is determined that the source of the communication frame received by the sub-antenna 61 is the smart device 2. The position identification unit 58 may start the position identification process when the flag is set.

[0112] First, in S300, the position identification unit 58 acquires the reception strength of a communication frame transmitted from the smart device 2 at each sub-antenna 61. In this embodiment, the position identification unit 58 acquires the reception strength transmitted from each determination unit 59 (i.e., the determination units 59a, 59b, 59c, and 59d). That is, the position identification unit 58 acquires the reception strength when the determination unit 59 identifies the transmission source of the communication frame received by the sub-antenna 61 as the smart device 2.

[0113] Next, in S310, the position identifying unit 58 detects the position of the smart device 2. For example, the position identifying unit 58 detects the distance from each of the sub-antennas 61 to the smart device 2 based on the reception intensity signal from each determination unit 59. Then, the position identifying unit 58 identifies the position of the smart device 2 based on the distance from each of the sub-antennas 61 to the smart device 2, for example, by using a triangulation method or the like. The position of the smart device 2 may be represented by latitude and longitude, or may be represented by relative coordinates with a predetermined position of the vehicle 3 as the origin.

[0114] Next, in S320, the position specifying unit 58 stores the specified position of the smart device 2 in the memory 531, and outputs it to the object driving unit 57. Then, the position specifying unit 58 ends this position specifying process.

[0115] [2-2. Processing performed by smart devices] The mobile communication process executed by the smart device 2 will be described with reference to the flowcharts of FIGS.

[0116] <Mobile communication processing> For example, the mobile communication process executed by the mobile control unit 23 (i.e., the communication unit 24) of the smart device 2 is repeatedly executed while the application of the smart entry start system is running on the smart device 2, for example.

[0117] In S400, the communication unit 24 determines whether or not an iBeacon including vehicle information (i.e., a vehicle ID) capable of identifying a vehicle (i.e., a vehicle 3) that has been registered in advance (i.e., that has been previously associated with the smart device 2) has been received. If an iBeacon including a vehicle ID has not been detected, the communication unit 24 waits until an iBeacon including a vehicle ID is detected by repeating the process of S400. On the other hand, when the communication unit 24 detects an iBeacon including a vehicle ID, the communication unit 24 shifts the process to S410.

[0118] In S410, the communication unit 24 broadcasts an advertisement packet including the mobile ID via the mobile transceiver 22 and the mobile antenna 21. The mobile ID is information with which the smart device 2 can be identified.

[0119] Next, in S420, the communication unit 24 determines whether a predetermined fixed time has elapsed since receiving an iBeacon including a vehicle ID in S400. If it is determined that the fixed time has elapsed, the communication unit 24 shifts the process to S430, stops transmitting the advertising packet in S430, shifts the process to S400, and repeats the processes from S400 onwards. On the other hand, if it is determined that the fixed time has not elapsed, the communication unit 24 shifts the process to S440.

[0120] In S440, the communication unit 24 determines whether or not a connection request has been received. If the communication unit 24 has not received a connection request, the communication unit 24 shifts the process to S420 and repeats the processes from S420 onward. On the other hand, if the communication unit 24 receives a connection request, the communication unit 24 shifts the process to S450.

[0121] Next, in S450, the communication unit 24 stops transmitting the advertisement packet. In the next step S460, the communication unit 24 performs pairing with the in-vehicle device 4 that sent the connection request in accordance with the BLE standard specifications, and after the pairing is completed, establishes a connection for short-range wireless communication in a method compliant with BLE.

[0122] Next, in S470, the communication unit 24 executes BLE communication with the in-vehicle device 4 with which the connection has been established. The BLE communication executed by the communication unit 24 will be described later. In the next step S480, the communication unit 24 determines whether or not a termination operation has been performed to terminate the BLE communication with the vehicle 3 (i.e., the in-vehicle device 4) with which the connection has been established. Examples of the termination operation include an operation of the smart device 2 turning off the BLE communication, an operation of the smart device 2 terminating an app, and the smart device 2 moving out of the connection range. Here, if it is determined that no termination operation has been performed, the communication unit 24 returns the process to S470 and continues the BLE communication with the vehicle 3 (i.e., the in-vehicle device 4) with which the connection has been established.

[0123] On the other hand, if it is determined that an end operation has been performed, the communication unit 24 ends the present mobile communication process. <BLE communication processing in smart devices> Next, the BLE communication process executed by the communication unit 24 of the mobile control unit 23 in S470 of the mobile communication process will be described with reference to FIG.

[0124] The communication unit 24 performs initial settings in S500-S510. For example, in S500, the communication unit 24 sets an initial value of NESN (hereinafter also referred to as initial value NESN) and an initial value of SN (hereinafter also referred to as initial value SN). Also, it sets the maximum value that NESN and SN can take (hereinafter referred to as MAX value). In BLE communication, the initial values ​​of NESN and SN are 0, and the MAX value is 1. The respective initial values ​​and MAX values ​​may be stored in the memory 231 in advance.

[0125] In the next S505, the communication unit 24 sets the predicted NESN value to the initial value NESN (i.e., 0), and sets the predicted SN value to the initial value SN (i.e., 0). The predicted NESN is a value of the NESN predicted to be set as the NESN included in a communication frame to be received and originating from the in-vehicle device 4 (i.e., a communication frame from the in-vehicle device 4 to the smart device 2). The predicted SN is a value of the SN predicted to be set as the SN included in a communication frame to be received and originating from the in-vehicle device 4.

[0126] In the next step S510, the communication unit 24 determines whether or not any signal has been received. If no signal has been received, the communication unit 24 waits until any signal is received by repeating the process of S510. For example, the communication unit 24 determines that any signal has been received when the reception strength of the signal received via the mobile antenna 21 is equal to or greater than a predetermined signal threshold.

[0127] Next, in S515, the communication unit 24 determines whether or not the communication frame whose source is the in-vehicle device 4 has been normally received. Normal reception here means that the communication frame has been received without error and that there has been no retransmission request.

[0128] Here, when it is determined that the communication frame originating from the in-vehicle device 4 has not been normally received, the communication unit 24 shifts the process to S520. In S520, the communication unit 24 sets the predicted NESN value as the NESN included in the communication frame originating from the smart device 2, and sets the predicted SN value as the SN included in the communication frame originating from the smart device 2. Note that MD is set to 0.

[0129] In the next S525, the communication unit 24 sets the header other than the NESN, SN, and MD in accordance with the standard specifications of BLE, and generates a communication frame (i.e., a communication frame of a data packet). The communication unit 24 transmits the generated communication frame via the mobile antenna 21 and the mobile transceiver 22, and returns the process to S510.

[0130] On the other hand, when it is determined that the communication frame transmitted from the in-vehicle device 4 has been normally received, the communication unit 24 stores the NESN, SN, and MD included in the received communication frame in the memory 231, and shifts the process to S530. Hereinafter, the NESN, SN, and MD included in the received communication frame are also referred to as the received NESN, received SN, and received MD.

[0131] In S530, the communication unit 24 determines whether or not the value of the received NESN (received NESN+1), that is, the NESN of the communication frame predicted to be transmitted next from the vehicle-mounted device 4, is greater than the MAX value.

[0132] Here, when it is determined that the value of the received NESN+1 is equal to or less than the MAX value, the communication unit 24 shifts the process to S535. In S535, the communication unit 24 sets the received NESN+1 as a new NESN value, and sets the received SN+1 as a new SN value. As a result, for example, NESN=1 and SN=1 are set in S535. Subsequently, in S540, the communication unit 24 sets the predicted NESN+1 as a new predicted NESN, and sets the predicted SN+1 as a new predicted SN. As a result, for example, predicted NESN=1 and predicted SN=1 are set in S540. Then, the communication unit 24 shifts the process to S555.

[0133] On the other hand, when it is determined that the value of the received NESN+1 is greater than the MAX value, the communication unit 24 shifts the process to S545. In S545, the communication unit 24 initializes the values ​​of NESN and SN. That is, NESN is set to the initial value NESN (i.e., 0), and SN is set to the initial value SN (i.e., 0). Next, in S550, the communication unit 24 initializes the predicted NESN and predicted SN. That is, the predicted NESN is set to the initial value NESN (i.e., 0), and the predicted SN is set to the initial value SN (i.e., 0). Then, the communication unit 24 shifts the process to S555.

[0134] In S555, the communication unit 24 determines whether or not further continuous transmission is to be performed on the same channel in the smart device 2. For example, when data to be transmitted from the smart device 2 is divided by frame division and the data to be transmitted is not the last data divided by frame division, the communication unit 24 may determine that further continuous transmission is to be performed on the same channel.

[0135] In addition, if frame division is not performed, and if the data to be transmitted is divided by frame division and the data to be transmitted is the last data divided by frame division, it may be determined that no further consecutive transmissions will be performed on the same channel.

[0136] Here, if it is determined that no further consecutive transmissions will be performed, the communication unit 24 proceeds to S560, sets MD to 0 in S560, and proceeds to S570. On the other hand, if it is determined that further consecutive transmissions will be performed, the communication unit 24 proceeds to S565, sets MD to 1 in S565, and proceeds to S570.

[0137] In the next S570, communication unit 24 sets the header other than NESN, SN, and MD in accordance with the standard specifications of BLE, generates a communication frame, and transmits the generated communication frame via mobile antenna 21 and mobile transceiver 22. Communication unit 24 stores in memory 231 the values ​​of NESN, SN, and MD included in the transmitted communication frame.

[0138] The communication frame transmitted from the smart device 2 in this manner is a communication frame including the second direction information. The second direction information is communication direction information indicating that the communication direction is the second direction. Specifically, the above-mentioned NESN and SN, which are a combination of values ​​different from each other, correspond to the second direction information. In other words, when the communication unit 24 receives a communication frame including the first direction information from the in-vehicle device 4, the communication unit 24 generates, as the second direction information, communication direction information in which the current pair frame information and the next pair frame information are different from each other.

[0139] Next, in S575, the communication unit 24 determines whether or not MD included in the header of the communication frame transmitted from the smart device 2 or received from the in-vehicle device 4 is 0, based on the contents stored in the memory 231. If it is determined that MD is 1, the communication unit 24 shifts the process to S510 and repeats the subsequent processes. On the other hand, if it is determined that MD is 0, the communication unit 24 ends this BLE communication process.

[0140] [3. Effects] According to the embodiment described above in detail, the following effects are achieved. (3a) In the above-described in-vehicle apparatus 4, the in-vehicle control unit 53 (i.e., the BLE communication unit 55) generates first direction information (i.e., NESN and SN where NESN=NS) in S170 or S175, and transmits a communication frame including the first direction information via the main antenna 51. In the smart device 2, when it is determined in S515 that a signal including the first direction information has been received, the mobile control unit 23 (i.e., the communication unit 24) generates second direction information in S535 or S545, and transmits a communication frame including the second direction information.

[0141] When the communication frame received by the sub-antenna 61 includes the second direction information, the monitor control unit 63 (that is, the determination unit 59) determines that the source of the communication frame is the second communication device.

[0142] That is, when the second direction information is included in the received communication frame, the in-vehicle device 4 determines that the transmission source of the received communication frame is the smart device 2. This makes it possible to more accurately identify the signal whose transmission source is the smart device 2 than when a received signal acquired at a pre-estimated timing (for example, the end of the interval period Ti) is always estimated to be the signal whose transmission source is the smart device 2.

[0143] (3b) In the above-described in-vehicle device 4, when the determination unit 59 determines that the source of the communication frame received by the sub-antenna 61 is the smart device 2, the location determination unit 58 determines the location of the smart device 2 based on the reception strength at the time of receiving the communication frame. As a result, the location is determined based on the reception strength of the signal whose transmission source is determined to be the smart device 2, so that the location of the smart device 2 can be determined with high accuracy.

[0144] (3c) In the above-mentioned in-vehicle device 4, the communication direction information includes SN as the current pair frame information and NESN as the next pair frame information. The in-vehicle control unit 53 (i.e., the BLE communication unit 55) generates, as the first direction information, communication direction information in which SN and NESN are equal to each other. In the above-mentioned smart device 2, the mobile control unit 23 generates, as the second direction information, communication direction information in which NS and NESN are different from each other.

[0145] In other words, the communication direction and the source are identified by whether the SN and the NESN match or do not match. This makes it easier to identify the communication direction and the source of the communication frame than, for example, identifying the mobile ID or the vehicle ID included in the communication frame to identify the communication direction and the source of the communication frame. As a result, the source of the communication frame can be identified with a simple configuration.

[0146] (3d) In the above-described in-vehicle device 4, the SN as the current pair frame information and the NESN as the next pair frame information are indicated by different numerical values. By using numerical values, communication direction information can be expressed easily. As a result, the transmission source of the communication frame can be identified by a simpler configuration.

[0147] (3e) In the above-described in-vehicle device 4, the SN as the current pair frame information and the NESN as the next pair frame information are either 0 or 1. That is, the SN is represented by 1 bit, and the NESN is represented by 1 bit. This makes it possible to represent communication direction information with a relatively small amount of information, that is, 2 bits (i.e., 2 bits for both the SN and the NESN).

[0148] (3f) In the above-described in-vehicle device 4, the communication direction information (i.e., SN and NESN) is included in the non-encrypted portion of the communication frame. This eliminates the need to have a function for decrypting the encrypted communication frame in order to identify the source of the communication frame, and allows a device for receiving the communication frame, such as the monitor device 6 (i.e., the monitor receiver 62 or the monitor control unit 63), to be easily configured.

[0149] (3g) In the communication system 1 including the above-mentioned in-vehicle device 4 and the above-mentioned smart device 2, the wireless communication is wireless communication conforming to the BLE standard. This allows the in-vehicle device 4 and the smart device 2, which perform bidirectional BLE communication, to accurately identify the source of the communication frame.

[0150] <Correspondence> In the above embodiment, the communication system 1 corresponds to the communication system, the in-vehicle device 4 corresponds to the first communication device and the in-vehicle device, and the smart device 2 corresponds to the second communication device. The main antenna 51 corresponds to the main antenna, the sub-antenna 61 corresponds to the sub-antenna, and the monitor receiver 62 corresponds to the intensity detection unit. The mobile antenna 21 corresponds to the transmitting / receiving antenna.

[0151] The in-vehicle control unit 53 and the BLE communication unit 55 correspond to a first communication execution unit, the monitor control unit 63 and the determination unit 59 correspond to a source determination unit, and the in-vehicle control unit 53 and the location identification unit 58 correspond to a location identification unit. The mobile control unit 23 and the communication unit 24 correspond to a second communication execution unit. NE corresponds to current pair frame information, NESN corresponds to next pair frame information, and NE and NESN correspond to communication direction information. NE and NESN where NE=NESN correspond to first direction information, and NE and NESN where NE≠NESN correspond to second direction information. Communication frames and communication frames indicating data packets correspond to communication frames for wireless communication.

[0152] [4. Other embodiments] Although the 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 modified forms.

[0153] (4a) In the above-described communication system 1, frame division may not be performed. In that case, for example, in the in-vehicle device 4, S120-S130 and S160-S175 shown in Fig. 10 may be deleted. Also, in the smart device 2, S555-S565 shown in Fig. 15 may be deleted.

[0154] (4b) In the above-described communication system 1, the NESN and SN are used as communication direction information, but the present disclosure is not limited to this. For example, communication direction information such as current pair frame information and next pair frame information may be assigned to a non-encrypted portion of a communication frame (e.g., a reserved area in a header portion, etc.).

[0155] (4c) In the above-described communication system 1, the monitor receiver 62 includes the determination unit 59. However, the present disclosure is not limited to this. For example, the in-vehicle control unit 53 may include the determination unit 59.

[0156] (4d) In the above-described communication system 1, the in-vehicle device 4 may include one monitor device 6. That is, the in-vehicle device 4 may include one sub-antenna 61. (4e) In the above-described communication system 1, the wireless communication between the in-car device 4 and the smart device 2 may be communication conforming to a communication standard other than BLE. In addition, the frequency band of the signal used for the wireless communication may be a frequency band other than the 2.4 GHz band.

[0157] (4f) The in-vehicle control unit 53, the monitor control unit 63, and the method thereof described in the present disclosure may be realized by a dedicated computer provided by configuring a processor and a memory programmed to execute one or more functions embodied in a computer program. Alternatively, the in-vehicle control unit 53, the monitor control unit 63, and the method thereof described in the present disclosure may be realized by a dedicated computer provided by configuring a processor with one or more dedicated hardware logic circuits. Alternatively, the in-vehicle control unit 53, the monitor control unit 63, and the method thereof described in the present disclosure may be realized by one or more dedicated computers configured by a combination of a processor and a memory programmed to execute one or more functions and a processor configured with one or more hardware logic circuits. In addition, the computer program may be stored in a computer-readable non-transient tangible recording medium as instructions executed by a computer. The method for realizing the functions of each unit included in the in-vehicle control unit 53 and the monitor control unit 63 does not necessarily need to include software, and all of the functions may be realized using one or more hardware.

[0158] (4g) Multiple functions possessed by one component in the above embodiments may be realized by multiple components, or one function possessed by one component may be realized by multiple components. Also, multiple functions possessed by multiple components may be realized by one component, or one function realized by multiple components may be realized by one component. Also, part of the configuration of the above embodiments may be omitted. Also, at least part of the configuration of the above embodiments may be added to or substituted for the configuration of another of the above embodiments.

[0159] (4h) In addition to the above-mentioned communication system 1, in-vehicle device 4, in-vehicle control unit 53, monitor control unit 63, smart device 2, and mobile control unit 23, the present disclosure can also be realized in various forms, such as a program for causing the in-vehicle control unit 53, the monitor control unit 63, and the mobile control unit 23 to function, a non-transient physical recording medium such as a semiconductor memory on which this program is recorded, a communication method, a position detection method, etc. [Explanation of symbols]

[0160] 1...communication system, 2...smart device, 3...vehicle, 4...in-vehicle device, 6...monitor device, 21...mobile antenna, 23...mobile control unit, 51...main antenna, 53...in-vehicle control unit, 55...BLE communication unit, 59...determination unit, 61...sub-antenna, 63...monitor control unit.

Claims

1. An in-vehicle device (4) used as a first communication device (4) in a communication system (1) including a first communication device (4) and a second communication device (2) that perform bidirectional wireless communication, the in-vehicle device (4) being mounted on a vehicle, a main antenna (51) configured to transmit and receive signals; At least one sub-antenna (61) configured to receive signals, the sub-antenna being different from the main antenna; a first communication execution unit (53, 55) configured to generate first direction information, which is communication direction information included in the paired communication frames and indicates a communication direction of the communication frames, and indicates that the communication direction is the first direction, for pairing a communication frame for wireless communication that is transmitted in a first direction from the first communication device to the second communication device and a communication frame for wireless communication that is transmitted in a second direction from the second communication device to the first communication device, and to transmit the communication frame including the first direction information via the main antenna; a determination unit (63, 59) configured to determine whether a source of the communication frame is the second communication device; Equipped with the second communication device is configured to be portable and includes a transmitting / receiving antenna (21) configured to transmit and receive a signal, and a second communication execution unit (23, 24) configured to generate the second direction information when a signal including the first direction information is received via the transmitting / receiving antenna, and to transmit the communication frame including the generated second direction information; the determination unit determines that a transmission source of the communication frame is the second communication device when the communication frame received by the sub-antenna includes second direction information that is the communication direction information and indicates that the communication direction is the second direction. In-vehicle device.

2. The in-vehicle device according to claim 1 , An intensity detection unit (62) configured to detect the reception intensity of a received signal at the sub-antenna; a location identification unit (53, 58) configured to identify a location of the second communication device based on the reception strength when the determination unit determines that the source of the communication frame received by the sub-antenna is the second communication device; The in-vehicle device further comprises:

3. 3. The in-vehicle device according to claim 1, The pair of communication frames is treated as a pair frame, the communication direction information includes current pair frame information indicating a pair frame including the communication frame to be transmitted, and next pair frame information indicating a pair frame including the communication frame to be received next, In the first communication device, the first communication execution unit generates, as the first direction information, the communication direction information in which the current pair frame information and the next pair frame information are equal to each other; In the second communication device, The second communication execution unit generates, as the second direction information, the communication direction information in which the current pair frame information and the next pair frame information are different from each other. In-vehicle device.

4. The in-vehicle device according to claim 3, The current pair frame information and the next pair frame information are represented by numerical values. In-vehicle device.

5. The in-vehicle device according to claim 3 or 4, The current pair frame information and the next pair frame information are represented by either 0 or 1. In-vehicle device.

6. The in-vehicle device according to any one of claims 1 to 5, The communication direction information is included in a non-encrypted portion of the communication frame. In-vehicle device.

7. The in-vehicle device according to any one of claims 1 to 6, The wireless communication between the first communication device and the second communication device is wireless communication according to the Bluetooth Low Energy (Bluetooth is a registered trademark) standard. In-vehicle device.

8. A communication system (1) including a first communication device (4) and a second communication device (2) that perform bidirectional wireless communication, The first communication device is a main antenna (51) configured to transmit and receive signals; At least one sub-antenna (61) configured to receive a signal, different from the main antenna; a first communication execution unit (53, 55) configured to generate first direction information, which is communication direction information included in the paired communication frames and indicates a communication direction of the communication frames, and indicates that the communication direction is the first direction, for pairing a communication frame for wireless communication that is transmitted in a first direction from the first communication device to the second communication device and a communication frame for wireless communication that is transmitted in a second direction from the second communication device to the first communication device, and to transmit the communication frame including the first direction information via the main antenna; a determination unit (63, 59) configured to determine whether a source of the communication frame is the second communication device; Equipped with the second communication device is configured to be portable and includes a transmitting / receiving antenna (21) configured to transmit and receive a signal, and a second communication execution unit (23, 24) configured to generate the second direction information when a signal including the first direction information is received via the transmitting / receiving antenna, and to transmit the communication frame including the generated second direction information; In the first communication device, when the communication frame received by the sub-antenna includes second direction information that is the communication direction information and indicates that the communication direction is the second direction, the determination unit determines that the transmission source of the communication frame is the second communication device. Communication systems.

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