Patent Application
20230388945
The present application is based on and claims the benefit of priority of Japanese Patent Application No. 2022-086240, filed on May 26, 2022, the disclosure of which is incorporated herein by reference.
The present disclosure relates to a communication system having at least one master communication device and multiple slave communication devices, more specifically to a technique for identifying an abnormal position when the communication system has an abnormality.
There has been known a wireless communication device configured to determine failure in a wireless network. The wireless communication device has a failure determination unit. The failure determination unit refers to a packet loss rate table, and identifies wireless communication terminal(s) whose packet loss rate is equal to or higher than a predetermined threshold. When all wireless communication terminals have packet loss rates equal to or higher than the threshold, the failure determination unit determines that the wireless communication device has a failure. On the other hand, when the wireless communication terminals whose packet loss rate is equal to or higher than the threshold are part of all wireless communication terminals, the failure determining unit determines that the wireless communication terminal whose packet loss rate is equal to or higher than the threshold has a failure.
A communication system according to one aspect of the present disclosure includes at least one master communication device; and a plurality of slave communication devices. The at least one master communication device is capable of wirelessly communicating with each of the plurality of slave communication devices. The at least one master communication device includes a communication characteristics obtainer obtaining information indicative of communication characteristics related to wireless communication while performing the wireless communication with each of the plurality of slave communication devices. The communication system further includes: a recorder recording a combination of the at least one master communication device and at least one of the plurality of slave communication devices having a communication abnormality when performing wireless communication between the at least one master communication device communicates and each of the plurality of slave communication devices; and an abnormal position finalization unit (i) instructing the at least one master communication device to perform wireless communication with at least one of the plurality of slave communication devices, (ii) determining, during performing the wireless communication, whether the wireless communication between the at least one master communication device and the at least one of the plurality of slave communication devices has been performed normally or abnormally based on the communication characteristics obtained by the communication characteristics obtainer, (iii) determining, as an abnormality-determined position, a position where an abnormality is occurring based on a normal/abnormal determination result of the wireless communication between the at least one master communication device and the at least one of the plurality of slave communication devices, and (iv) finalizing the abnormality-determined position as an abnormal position where the abnormality is occurring when the abnormality-determined position is consistent with the combination of the at least one master communication device and the at least one of the plurality of slave communication devices having a communication abnormality recorded in the recorder.
The above and other objects, features and advantages of the present disclosure will become more apparent from the following detailed description made with reference to the accompanying drawings. In the drawings:
Next, a relevant technology will be described first only for understanding the following embodiments. A typical wireless communication device as described above determines a failure of the wireless communication device or a failure of the wireless communication terminal based on the packet loss rate in communication between the wireless communication device and the wireless communication terminal.
However, since such determination is simply based on the packet loss rate, even when communication failure occurs due to external factors (for example, interference with external radio waves, etc.), the wireless communication device or wireless communication terminal may mistakenly be determined as having a failure.
It is one objective of the present disclosure to provide a communication system capable of determining an abnormal position in the communication system when having an abnormality in the system.
According to a first aspect of the present disclosure, a communication system includes at least one master communication device; and a plurality of slave communication devices. The at least one master communication device is capable of wirelessly communicating with each of the plurality of slave communication devices. The at least one master communication device includes a communication characteristics obtainer obtaining information indicative of communication characteristics related to wireless communication while performing the wireless communication with each of the plurality of slave communication devices. The communication system further includes: a recorder recording a combination of the at least one master communication device and at least one of the plurality of slave communication devices having a communication abnormality when performing wireless communication between the at least one master communication device communicates and each of the plurality of slave communication devices; and an abnormal position finalization unit (i) instructing the at least one master communication device to perform wireless communication with at least one of the plurality of slave communication devices, (ii) determining, during performing the wireless communication, whether the wireless communication between the at least one master communication device and the at least one of the plurality of slave communication devices has been performed normally or abnormally based on the communication characteristics obtained by the communication characteristics obtainer, (iii) determining, as an abnormality-determined position, a position where an abnormality is occurring based on a normal/abnormal determination result of the wireless communication between the at least one master communication device and the at least one of the plurality of slave communication devices, and (iv) finalizing the abnormality-determined position as an abnormal position where the abnormality is occurring when the abnormality-determined position is consistent with the combination of the at least one master communication device and the at least one of the plurality of slave communication devices having a communication abnormality recorded in the recorder.
According to a second aspect of the present disclosure, a communication system includes: at least one master communication device; and a plurality of slave communication devices. The at least one master communication device is capable of wirelessly communicating with each of the plurality of slave communication devices. The at least one master communication device includes at least one first processor programmed to obtain information indicative of communication characteristics related to wireless communication while performing the wireless communication with each of the plurality of slave communication devices. The communication system further comprises at least one second processor programmed to: record a combination of the at least one master communication device and at least one of the plurality of slave communication devices having a communication abnormality when performing wireless communication between the at least one master communication device communicates and each of the plurality of slave communication devices; instruct the at least one master communication device to perform wireless communication with at least one of the plurality of slave communication devices; determine, during performing the wireless communication, whether the wireless communication between the at least one master communication device and the at least one of the plurality of slave communication devices has been performed normally or abnormally based on the obtained communication characteristics; determine, as an abnormality-determined position, a position where an abnormality is occurring based on a normal/abnormal determination result of the wireless communication between the at least one master communication device and the at least one of the plurality of slave communication devices; and finalize the abnormality-determined position as an abnormal position where the abnormality is occurring when the abnormality-determined position is consistent with the recorded combination of the at least one master communication device and the at least one of the plurality of slave communication devices having a communication abnormality.
According to a third aspect of the present disclosure, a method for a communication system including: at least one master communication device; and a plurality of slave communication devices. The at least one master communication device is capable of wirelessly communicating with each of the plurality of slave communication devices. The at least one master communication device includes at least one first processor programmed to obtain information indicative of communication characteristics related to wireless communication while performing the wireless communication with each of the plurality of slave communication devices. The method includes: recording a combination of the at least one master communication device and at least one of the plurality of slave communication devices having a communication abnormality when performing wireless communication between the at least one master communication device communicates and each of the plurality of slave communication devices; instructing the at least one master communication device to perform wireless communication with at least one of the plurality of slave communication devices; determining, during performing the wireless communication, whether the wireless communication between the at least one master communication device and the at least one of the plurality of slave communication devices has been performed normally or abnormally based on the obtained communication characteristics; determining, as an abnormality-determined position, a position where an abnormality is occurring based on a normal/abnormal determination result of the wireless communication between the at least one master communication device and the at least one of the plurality of slave communication devices; and finalizing the abnormality-determined position as an abnormal position where the abnormality is occurring when the abnormality-determined position is consistent with the recorded combination of the at least one master communication device and the at least one of the plurality of slave communication devices having a communication abnormality.
As described above, according to the communication system and the method of the present disclosure, the abnormal position finalization unit determines an abnormality-determined position where an abnormality is occurring based on a determination result of whether wireless communication between the master communication device and at least part of the plurality of slave communication devices is normal or abnormal. Further, the abnormal position finalization unit finalizes the abnormality-determined position as an abnormal position, upon confirming matching between (a) the abnormality-determined position and (b) the combination of the master communication device and the slave communication device having a communication abnormality recorded in the recorder. Therefore, when an abnormality is occurring in the communication system, an abnormal position where an abnormality is occurring is determinable with high accuracy.
Hereinafter, an embodiment of a communication system according to the present disclosure is described in detail with reference to the drawings. In a plurality of drawings, the same or similar parts may be denoted by the same reference numerals, and overlapping descriptions may be omitted.
The communication system 100 according to the present embodiment is installed in a vehicle, for example, and used to perform communication between plural pieces of in-vehicle equipment and at least one control unit that controls and manages the plural pieces of in-vehicle equipment. In such case, for example, at least one master communication device 20 is connected to at least one control unit, and a plurality of slave communication devices 30 are connected to each of the plural pieces of in-vehicle equipment. The master communication device 20 and the plurality of slave communication devices are each arranged at a fixed position in the vehicle. However, the master communication device 20 and the plurality of slave communication devices 30 are not necessarily arranged at a fixed position.
As a specific application in vehicles, the communication system 100 according to the present embodiment is applied to a battery management system that manages batteries mounted as battery packs in electrified vehicles, such as, for example, electric vehicles, hybrid vehicles, and plug-in hybrid vehicles and the like. In a battery management system, a monitoring device as an in-vehicle equipment is provided for each of a plurality of battery stacks forming a battery pack. Each of the monitoring devices for a plurality of battery stacks obtains battery information such as the voltage and current of each battery cell included in the battery stack and the temperature of the battery stack using various sensors and the like.
When each of the monitoring devices receives data requesting battery information from a battery control device as a control unit via the communication system 100, each of the monitoring devices sends the obtained battery information to the battery control device via the communication system 100. Based on the obtained battery information, the battery control device calculates the state of charge (SOC) of the entire battery stack, drives the temperature raising/cooling mechanism to adjust the temperature of the battery pack to an appropriate range, and determines whether or not it is necessary to perform a so-called equalization process to equalize the voltages of each of the battery cells. When the battery control device determines that at least one battery stack needs to perform the equalization process, it instructs the corresponding monitoring device to perform the equalization process via the communication system 100.
Alternatively, the communication system 100 according to the present embodiment may be applied to a so-called smart key system or to a tire air pressure monitoring system in a vehicle. In an application to the smart key system, for example, the master communication device 20 is disposed in a vehicle, and is connected to a control device that controls a lock-unlock of a door of the vehicle, or that controls an ON-OFF of a drive power source such as an engine or the like. The plurality of slave communication devices 30 are each disposed in a portable key (i.e., a key fob) or in a portable terminal, which is carried by a plurality of users. In an application to the tire air pressure monitoring system, the master communication device is disposed in a vehicle, and is connected to a control device that provides warning or the like when a tire air pressure display or an air pressure itself has an abnormality. The plurality of slave communication devices 30 are each disposed in each of tires, and are each connected to an air pressure detection device that is disposed in each of tires. Further, the communication system 100 may also be applicable to a vehicle diagnosis system. In such case, the plurality of slave communication devices are connected to a plurality of in-vehicle devices having a self-diagnosis function, and the master communication device is connected to a diagnosis control device disposed in a service factory. In the examples described above, at least one of the master communication device and the plurality of slave communication devices is disposed at a fixed position, and/or at least one of the master and slave is disposed in a vehicle.
However, application examples of the communication system according to the present embodiment are not limited to vehicles, but to systems that control and manage various equipment in mobile objects other than vehicles, i.e., objects including aerial object such as drones, ships, construction machinery, agricultural machinery and the like. Furthermore, the communication system according to the present embodiment is also applicable to a system for controlling and managing various types of building equipment such as buildings and production facility such as factories.
The master communication device 20 is configured to be able to wirelessly communicate with each of the plurality of slave communication devices 30 on multiple frequency channels. For wireless communication between the master communication device 20 and each of the plurality of slave communication devices 30, for example, BLUETOOTH LOW ENERGY (BLE, where BLUETOOTH is a registered trademark) can be used. Alternatively, other wireless communication technologies including wireless LAN such as Wi-Fi (registered trademark) may be used.
In the configuration shown in
Alternatively, at least one control unit may be configured to communicate with the plurality of slave communication devices 30A to 30E using the first and second master communication devices 20A and 20B from a time when the communication system 100 is still operating normally. That is, the first master communication device may be configured to handle wireless communication with some of the plurality of slave communication devices 30A to 30E, and the second master communication device 20B may be configured to handle wireless communication with the rest of the plurality of slave communication devices 30A to 30E. In such case, the first and second master communication devices 20A and 20B communicate with different slave communication devices 30A to 30E at the same time, thereby increasing communication speed of communication between the master communication device and the plurality of slave communication devices 30A to 30E. Furthermore, when one of the first and second master communication devices 20A and 20B fails, the control unit can still use the other of the first and second master communication devices and 20B to communicate with the plurality of slave communication devices 30A to 30E.
Thus, according to the communication system 100 of the present disclosure, by connecting a plurality of master communication devices 20A and 20B to at least one control unit, even when one master communication device 20A or 20B fails, the control unit and various kinds of equipment such as an in-vehicle equipment can continue to communicate with each other.
As shown in
The management device 10 has, as functions executed by the microcontroller 11, a self-diagnosis unit 12 that performs self-diagnosis, an abnormal position finalization unit 13 that finalizes an abnormal position, and a reference characteristic update unit 14 that updates reference communication characteristics. The self-diagnosis unit 12, the abnormal position finalization unit 13, and the reference characteristic update unit 14 are described later in detail. In addition, the microcontroller 11 of the management device 10 has a storage unit 15 storing in a storage medium, for each of the slave communication devices 30, the reference communication characteristics of each frequency channel when the master communication device 20 communicates with each of the plurality of slave communication devices 30 on multiple frequency channels In
The master communication device 20 has, as a function executed by the microcontroller 21, a communication characteristics obtainer 22 that obtains information indicating communication characteristics related to wireless communication while performing wireless communication with each of the slave communication devices 30, and a communication NG recorder 23 for recording a slave communication device 30 to which connection cannot be established or with which communication cannot be performed. For example, the communication characteristics obtainer 22 obtains, as communication characteristic information, a received signal strength indicator (RSSI) indicating a reception strength of wireless communication, and a packet error rate (PER). The packet error rate may be replaced by bit error rate (BER). The bit error rate can be calculated from a packet error rate by a predetermined arithmetic expression.
As shown in
The microcontroller 21 of the master communication device 20 encrypts sending data such as battery information request data, for example, using encryption information exchanged in a connection mode described later, and outputs the encrypted sending data to the wireless communicator 24. The wireless communicator 24 modulates the sending data output from the microcontroller 21 and sends it to the slave communication device 30 via an antenna. The wireless communicator 24 adds information required for wireless communication to the sending data and sends the data. Information required for wireless communication includes, for example, an identifier (ID), a sequence number, a next sequence number, an error detection code, and the like. The wireless communicator 24 also controls a data size, schedule, error detection, etc. of wireless communication.
The wireless communicator 32 of the slave communication device 30 receives the data sent from the wireless communicator 24 of the master communication device 20 via an antenna and demodulates it. The demodulated data is given to the microcontroller 31 of the slave communication device 30. For example, when the received data is a sending request for battery information, the microcontroller 31 of the slave communication device 30 sends the sending request to the corresponding battery stack monitoring device. The monitoring device outputs the obtained battery information to the slave communication device 30 in order to respond to the sending request. Then, the microcontroller 31 of the slave communication device sends the battery information output from the monitoring device to the wireless communicator 24 of the master communication device 20 via the wireless communicator 32.
Next, various processes executed in the communication system 100 according to the present embodiment are described.
However, in case where intermittent communication between the master communication device 20 and the slave communication device 30 is sufficient, such as when the communication system 100 is applied to the above-described battery management system, the process shown in the flowchart of
The connection mode process of step S100 and the data communication mode process of step S200 shown in the flowchart of
First, the details of the connection mode process are described with reference to the flowchart of
In the connection mode process, the master communication device 20 opens a scan window, and performs a scanning operation in step S105. For example, in the case of BLE, as a scanning operation, the master communication device 20 periodically puts a transmission channel of an advertisement packet (i.e., connection request) from the slave communication device 30 into a receivable state for a predetermined period of time. On the other hand, in step S140, the slave communication device 30 sends a connection request through a connection request transmission channel, and executes an advertising operation. A start of the scanning operation may be earlier than, approximately the same timing as, or later than a start of the advertising operation. The connection request includes ID information of itself (i.e., the slave communication device 30) and master communication device 20, and the like.
In step S110, the master communication device 20 receives data including a connection request from the slave communication device 30. Next, in step S115, the master communication device 20 determines whether the received data is normal, that is, whether the data including the connection request from the slave communication device 30 has been normally received based on the error detection code included in the received data, for example. If the received data is normal, the process proceeds to step S120. In step S120, the master communication device 20 sends data including a connection response to the slave communication device 30 that has sent data including the connection request. On the other hand, if the received data is not normal, the process proceeds to step S125. In step S125, the master communication device 20 determines whether it is necessary to perform self-diagnosis. For example, the master communication device 20 can determine that the self-diagnosis needs to be performed when the number of times the received data is determined as not normal reaches a predetermined number of times in step S115. When it is determined that the self-diagnosis needs to be performed, the master communication device 20 transitions to the self-diagnosis mode. When it is determined that the self-diagnosis is not necessary, the master communication device 20 returns to step S105, and continues the scanning operation.
In step S145, the slave communication device 30 receives data including the connection response from the master communication device 20. Next, in step S150, the slave communication device 30 determines whether the received data is normal, that is, whether the data including the connection response from the master communication device 20 has been normally received, based on the error detection code included in the received data, for example. When the received data is normal, the process proceeds to step S155. On the other hand, if the received data is not normal, the process returns to step S140, and the slave communication device 30 sends data including the connection request to the master communication device 20 again.
The master communication device 20 and the slave communication device perform a connection completion process in steps S130 and S155, respectively. The connection completion process includes a process for exchanging unique information. For example, in the process of exchanging unique information, the unique information held by the master communication device 20 and the slave communication device 30 are exchanged and stored in their respective memories. Accordingly, encryption using the exchanged unique information is possible. Unique information is, for example, key information or information for generating a key.
A connection is thus established between the master communication device and the slave communication device 30. Once the connection is established, the slave communication device 30 stops sending data including the connection request. Then, the master communication device 20 and the slave communication device 30 transition to the data communication mode.
Note that, before switching to the data communication mode, the master communication device 20 determines in step S135 whether or not it is necessary to perform self-diagnosis. In such determination, for example, the master communication device 20 can determine that the self-diagnosis needs to be performed in case that, even though the master communication device 20 itself has performed the connection completion process, the corresponding slave communication device 30 continues to send data including a connection request. Alternatively, the master communication device 20 may determine that it is necessary to perform self-diagnosis when such a state occurs continuously for a predetermined number of times.
The master communication device 20 (i.e., the first and second master communication devices 20A, 20B) individually performs the above-described connection mode process with each of the plurality of slave communication devices 30. When the master communication device 20 cannot establish a connection with the slave communication device 30 by the connection mode process described above, the communication NG recorder 23 records the slave communication device 30 to which the connection could not be established together with the time of such connection attempt. Note that the communication NG recorder 23 has a function of periodically recording (a) the slave communication devices 30 with which connection could not be established and (b) the slave communication devices 30 with which communication could not be established, together with the time at a predetermined cycle. Therefore, the slave communication device 30 that cannot establish a connection is recorded as the slave communication device 30 that has continuously failed to communicate in the recording of each predetermined cycle.
Next, details of the data communication mode process are described with reference to the flowchart of
In step S255, the slave communication device 30 opens a scan window according to connection parameters notified from the master communication device 20, and performs a scanning operation. Note that each of the slave communication devices 30, according to connection parameter settings, performs communication with the master communication device20 at respectively different timings. For example, in the case of BLE, connection parameters include a transmit window size that indicates a transmission period of data packets, a connection interval that indicates a frequency channel hop cycle, a channel mapping that indicates which data channel is to be used in a connection event, a hop increment that specifies an order of channel switching, and the like. Based on the above-described connection parameters, the slave communication device 30 puts, as a scanning operation, the signal of the frequency channel used for transmission into a receivable state at the timing when packet data is sent from the master communication device 20.
In step S205, the master communication device 20 sends a data request to the slave communication device 30 via the corresponding frequency channel in synchronization with the timing at which the slave communication device 30 opens the scan window. The slave communication device 30 receives the data request sent from the master communication device 20 in step S260. Next, in step S265, the slave communication device 30 determines whether the received data is normal, that is, whether the data request from the master communication device 20 has been normally received, for example, based on the error detection code included in the received data. When the received data is normal, the process proceeds to step S270. In step S270, the slave communication device 30 obtains the requested data from, for example, the control device of the corresponding equipment or the like, and sends it to the master communication device 20. On the other hand, when the received data is not normal, the slave communication device 30 returns to the process of step S255, opens the scan window according to the above connection parameters, and performs the scanning operation.
After sending the data request in step S205, the master communication device 20 performs, in step S210, a scanning operation to open a scan window in preparation for receiving packet data sent from the slave communication device 30. The master communication device 20 receives the packet data sent by the slave communication device 30 in step S215. Next, in step S220, the master communication device 20 determines whether the received data is normal, that is, whether the data sent by the slave communication device 30 has been normally received, based on the error detection code included in the received data, for example.
When the received data is correct, the master communication device 20 proceeds to the process of step S225. In step S225, the master communication device determines whether or not to end the data communication mode. For example, when the communication system 100 is applied to a vehicle, and the master communication device 20 and the slave communication device 30 continuously communicate with each other while the vehicle is in operation, the master communication device 20 may determine that the data communication mode ends in response to a turning off of the main switch of the vehicle. Alternatively, when the master communication device 20 and the slave communication device 30 intermittently communicate, the master communication device 20 may determine that the data communication mode has ended when a predetermined communication period has lapsed.
When determining that the data communication mode has ended, the master communication device 20 proceeds to the process of step S230. In step S230, the master communication device 20 sends an end request of data communication to the slave communication device 30. After that, the master communication device 20 transitions to the reference characteristics update mode. Also, when the slave communication device 30 determines in step S275 that it has received an end request of data communication from the master communication device 20, it transitions to the reference characteristics update mode. Note that the master communication device 20 may transition to the reference characteristics update mode without sending the end request of data communication. The slave communication device 30 does not necessarily have to distinguish between the data communication mode and the reference characteristics update mode. The slave communication device 30 may simply be configured to (a) send the requested data in response to receiving a data request from the master communication device 20, or (b) continuously send advertisement packets when the connection is not yet established or has ended. If the data communication mode does not end, the master communication device 20 returns to the process of step S205, and the slave communication device 30 returns to the process of step S255.
On the other hand, when the received data is not normal, the master communication device 20 proceeds to the process of step S235. In step S235, the master communication device 20 determines whether or not to resend the same data request as the already-sent data request. For example, in the case of BLE, whether or not to resend the same data request can be determined based on SN (Sequence Number) bit and NESN (Next Expected Sequence Number) bit included in the header. Initially, the SN bit and NESN bit are set to zero. When the data transmission from the master communication device 20 to the slave communication device 30 succeeds, the NESN bit is set to 1 in the next data transmission from the slave communication device to the master communication device 20. Then, since the NESN bit is 1, the master communication device 20 sends data with the SN bit set to 1 to the slave communication device 30. In the above case, when the NESN bit is 0, it means that the data transfer has failed. Therefore, the master communication device 20 can determine that it is necessary to resend the previously sent data whose SN bit is 0. Also, when using a wireless communication protocol other than BLE, it is possible to determine whether or not to resend based on ACK/NACK, for example. When resending, the master communication device 20 proceeds to the process of step S245 and sends the same data request as before on the same frequency channel or the next frequency channel after frequency hopping. When not resending due to repeated resending up to a predetermined number of times, the master communication device proceeds to the process of step S240.
In step S240, the master communication device 20 determines whether it is necessary to perform self-diagnosis. For example, the master communication device can determine that the self-diagnosis needs to be performed when the number of times the received data is determined as not normal reaches a predetermined number of times in step S220. When it is determined that the self-diagnosis needs to be performed, the master communication device 20 transitions to the self-diagnosis mode. When it is determined that the self-diagnosis is not necessary, the master communication device 20 returns to step S205.
In the above-described data communication mode process, when an abnormality occurs in data transmission/reception and the slave communication device is unable to perform normal communication, the master communication device 20 stores the abnormal slave communication device 30 recorded with time in the communication NG recorder 23.
Next, details of the reference characteristics update mode process is described with reference to the flowchart of
As described above, the storage unit 15 of the management device 10 stores, in a storage medium, the reference communication characteristics (RSSI, PER) for each of the slave communication devices 30 and regarding each frequency channel when performing communication between the master communication device 20 and the plurality of slave communication devices 30 on multiple frequency channels. The reference communication characteristics can be obtained by actually measuring RSSI and PER in a state where the master communication device 20 and the slave communication device 30 are disposed to an installation object such as a vehicle and arranged at predetermined positions, for example.
However, the reference communication characteristics may possibly change over time or with changes in the installation environment. Therefore, in the present embodiment, the reference communication characteristics stored in the storage unit 15 are updated when a predetermined update condition is satisfied. As the predetermined update condition, for example, a predetermined period of time has lapsed from previously performing the reference characteristics update mode process, the vehicle traveled distance has increased by a predetermined distance since the previous reference characteristics update mode process was performed, and/or an update instruction from outside has been received, etc., can be employed.
In step S305, the management device 10 determines whether or not to update the reference characteristics based on whether or not the predetermined update condition described above is satisfied. When updating the reference characteristics, the reference characteristics update unit 14 of the management device 10 instructs the master communication device 20 to communicate with each of the slave communication devices 30 via multiple frequency channels (preferably, via all frequency channels used in the data communication mode). In response to such instruction, the two master communication devices 20 respectively communicate with each of the slave communication devices 30. Note that, in the reference characteristics update mode, the master communication device 20 may communicate with each of the slave communication devices 30 using connection parameters different from those in the data communication mode.
Each of the slave communication devices 30 opens a scan window and performs a scanning operation according to the connection parameters notified from the master communication device 20 in step S355. Note that the connection parameters are set so that each of the slave communication devices 30 communicates with the master communication device 20 at respectively different timings. Here, when the above-described predetermined update condition is not satisfied and the update of the reference characteristics is not performed, even when the slave communication device 30 performs the scanning operation, it will not receive a data request from the master communication device 20. Therefore, when the slave communication device 30 does not receive a data request from the master communication device 20 even after the predetermined time has lapsed, the slave communication device 30 ends the reference characteristics update mode process without performing the process after step S360.
In step S310, the master communication device 20 sends a data request to each of the slave communication devices 30 via the corresponding frequency channel in synchronization with the timing at which each of the slave communication devices opens the scan window. Each of the slave communication devices 30 receives the data request sent from the master communication device 20 in step S360. Then, each of the slave communication devices 30 determines whether the received data is normal in step S365, for example, based on the error detection code included in the received data. If the received data is normal, the process proceeds to step S370. In step S370, each of the slave communication devices 30 sends packet data to the master communication device 20. This packet data may be empty or may contain some data. On the other hand, if the received data is not normal, each of the slave communication devices 30 returns to the process of step S355, opens a scan window and performs a scanning operation according to the above-described connection parameters.
After sending the data request in step S310, the master communication device 20 performs a scanning operation to open a scan window in preparation for receiving packet data sent from the slave communication device 30 in step S315. The master communication device 20 receives the packet data sent by the slave communication device 30 in step S320. At this time, the communication characteristics obtainer 22 of the master communication device 20 obtains RSSI indicating the reception strength of packet data from the slave communication device 30 as communication characteristics.
Next, in step S325, the master communication device 20 determines whether the received data is normal, for example, based on the error detection code included in the received data. At this time, the communication characteristics obtainer 22 of the master communication device 20 obtains a packet error rate indicating the proportion of packet data that could not be received normally among the packet data sent by the slave communication device 30.
When the received data is normal, the master communication device 20 proceeds to the process of step S330. In step S330, the master communication device determines whether or not the sending and receiving data required for updating the reference characteristics have been completed. For example, when sending and receiving data have not been performed with the individual slave communication devices 30 on most (i.e., the first predetermined number or more) or all of frequency channels, the master communication device 20 determines that required sending and receiving data (such as S330: REQUIRED COMM[UNICATION] COMPLETE?) have not been completed. In such case, the master communication device 20 returns to the process of step S310, changes the frequency channel, and repeats sending of the data request. On the other hand, if the master communication device 20 determines that required sending and receiving data have been completed, the process proceeds to step S345. In step S345, the management device 10 updates the reference communication characteristics stored in the storage unit 15 with the communication characteristics obtained by the communication characteristics obtainer 22 of the master communication device 20.
When the received data is not normal, the master communication device proceeds to the process in step S335. In step S335, the master communication device 20 determines whether or not to resend the same data request as the already-sent data request. When resending, the master communication device 20 proceeds to the process of step S340 and sends the same data request as before on the same frequency channel or the next frequency channel after frequency hopping. When not resending, the master communication device 20 returns to the process of step S310.
In step S350 performed after step S345, the master communication device sends an update mode end request to each of the slave communication devices 30 respectively. After that, the master communication device 20 ends the reference characteristics update mode process. When the slave communication device 30 determines in step S375 that it has received the update mode end request from the master communication device 20, it ends the reference characteristics update mode process. For the same reason as described above, the master communication device 20 does not have to send the update mode end request to each of the slave communication devices 30.
An example of (a) sending and receiving packet data between the master communication device 20 and the slave communication device 30, and (b) updating the reference communication characteristics stored in the storage unit 15 with the actual communication characteristics obtained by the sending and receiving data has been described above. However, the method of updating the reference communication characteristics is not limited to the example described above. For example, an external management server can collect communication characteristics from a plurality of communication systems 100 applied to vehicles of the same type, and can determine standard reference communication characteristics from the collected communication characteristics. Then, the management server may distribute the determined reference communication characteristics to each communication system 100, and in each communication system 100, the reference communication characteristics stored in the storage unit 15 may be updated with the distributed reference communication characteristics.
Next, the details of the self-diagnosis mode process are described with reference to the flowchart of
The self-diagnosis unit 12 of the management device 10 first determines whether or not the master communication device 20 has established connections with all of the slave communication devices 30 in step S405. When the master communication device 20 has not established connections with all of the slave communication devices 30, it is obvious that some kind of abnormality has occurred in the communication system 100. Therefore, the self-diagnosis unit 12 of the management device 10 transitions to the abnormal position finalization mode for identifying the abnormality occurrence position. On the other hand, when the master communication device 20 has established connections with all of the slave communication devices 30, the self-diagnosis unit 12 of the management device 10 proceeds to step S410.
In step S410, the self-diagnosis unit 12 of the management device 10 instructs the first and second master communication devices 20A and 20B to communicate with all of the slave communication devices 30A to 30E on multiple frequency channels and to obtain RSSI. In response to this instruction, wireless communication over multiple frequency channels is performed for all combinations of the master communication devices 20 and the slave communication device 30 perform, and the RSSI of each wireless communication is obtained. Each of the obtained RSSIs is provided from the master communication device 20 to the management device 10. Note that the self-diagnosis unit 12 of the management device 10 does not necessarily have to instruct the first and second master communication devices 20A and 20B to perform wireless communication with all of the slave communication devices 30A to 30E. For example, the self-diagnosis unit 12 of the management device 10 may instruct the first and second master communication devices 20A and 20B to perform wireless communication with some of the slave communication devices 30 in record of the communication NG recorder 23, including the slave communication device 30 having a communication abnormality, the slave communication device 30 that triggered the determination that self-diagnosis is required, and the like. Also, the multiple frequency channels may be all frequency channels, or may be not necessarily all but a second predetermined number or more of frequency channels.
In step S415, the self-diagnosis unit 12 of the management device 10 reads, from the storage unit 15, a reference RSSI, which is/are a reference communication characteristic or characteristics of each of multiple frequency channels on which the master communication device 20 has performed communication with each of the plurality of slave communication devices 30. Then, in step S420, the self-diagnosis unit 12 of the management device 10 determines, for each of the slave communication devices 30, an abnormality of wireless communication between the master communication device 20 and the plurality of slave communication devices 30 based on a strength of correlation between (a) an overall trend of the plurality of obtained RSSIs on the multiple frequency channels and (b) an overall trend of the reference RSSIs over the multiple frequency channels, in all combinations of the master communication device 20 and the slave communication devices 30.
Normality/abnormality determination based on the strength of correlation between the overall trend of the obtained RSSI and the overall trend of the reference RSSI is performed for each of the plurality of slave communication devices 30. In FIG. for the first and second master communication devices 20A and 20B indicated by “M1” and “M2” and all the slave communication devices 30A to 30E indicated by “S1” to “S5,” the table shows a state in which a determination of all normal has been made. In such case, in the determination process of step S425, it is determined that all combinations of communication between the master communication device 20 and the slave communication device 30 are normal. In such case, the process proceeds to step S450, and the self-diagnosis unit 12 of the management device 10 determines that the self-diagnosis is OK.
On the other hand, if all are not determined as normal in step S425, the process proceeds to step S430. In step S430, the self-diagnosis unit 12 of the management device 10 instructs the first and second master communication devices and 20B to communicate with all of the slave communication devices 30A to 30E on multiple frequency channels, and to obtain the PER. In response to this instruction, regarding all combinations of the master communication device 20 and the slave communication device 30, wireless communication on multiple frequency channels is performed, and the PER of each wireless communication (packet data communication) is obtained. The obtained PERs are provided from each of the master communication devices 20 to the management device 10. In addition, as described above, the self-diagnosis unit 12 of the management device 10 may instruct the first and second master communication devices 20A and 20B to perform wireless communication with not all the slave communication devices 30 but some of the slave communication devices 30. Also, the multiple frequency channels may be all frequency channels, or may be not necessarily all but a second predetermined number or more of frequency channels. Also, obtaining of the PER in step S430 may be performed simultaneously performed with obtaining of the RSSI in step S410 described above.
In step S435, the self-diagnosis unit 12 of the management device 10 reads, from the storage unit 15, the reference PER, which is/are a reference communication characteristic or characteristics of each of the multiple frequency channels when the master communication device 20 communicates with each of the plurality of slave communication devices 30 on the multiple frequency channels. Then, in step S440, the management device 10, for all combinations of the master communication device 20 and the slave communication devices 30, determines whether the wireless communication between the master communication device 20 and the plurality of slave communication devices 30 is normal or abnormal, for each of the slave communication devices 30, based on the strength of correlation between the overall trend of the plurality of obtained PERs over the multiple frequency channels for each of the slave communication devices 30 and the overall trend of the reference PER.
Note that the strength of the correlation between the overall trend of the obtained PER and the overall trend of the reference PER may be, as shown in the example of
Determination of normality or abnormality based on the strength of correlation between the overall trend of the obtained PER and the overall trend of the reference PER is performed regarding the first and second master communication devices 20A, 20B, for each of the plurality of slave communication devices 30. When all slave communication devices 30 are determined as normal, regarding the first and second master communication devices 20A and 20B, all combinations of the master communication devices 20 and the slave communication devices 30 are determined as normal by the determination process in step S445. In such case, the process proceeds to step S450, and the self-diagnosis unit 12 of the management device 10 determines that the self-diagnosis is OK. On the other hand, when all are not determined as normal in step S445, the self-diagnosis unit 12 of the management device 10 transitions to the abnormal position finalization mode.
In such manner, the self-diagnosis unit 12 of the management device 10 utilizes an overall trend of multiple communication characteristics of multiple frequency channels, for a determination of whether the wireless communication between the first and second master communication devices 20A, 20B and the plurality of slave communication devices 30A to 30E is normal or abnormal, about each of the slave communication devices 30A to 30E. Therefore, even in case that normal communication is not performable on some frequency channels due to an external factor, it is possible to prevent erroneous determination that one of the communication devices 20A, 20B, 30A to 30E has a failure.
In addition, the self-diagnosis unit 12 of the management device 10 transitions to the abnormal position finalization mode when at least one slave communication device 30 among the plurality of slave communication devices 30 is determined as abnormal in wireless communication, based on determinations of whether wireless communication is normal or abnormal for each of the slave communication devices 30.
In particular, the self-diagnosis unit 12 of the management device 10 first uses the RSSI as first communication characteristics information to determine, for each of the slave communication devices 30, whether the wireless communication between the master communication device 20 and the plurality of slave communication devices is normal or abnormal, regarding each of the first and second master communication devices 20A and 20B. When the management device 10 determines that at least one slave communication device 30 is abnormal in wireless communication in normality/abnormality determination of the wireless communication for each of the slave communication devices 30 using RSSI, the management device further uses the PER as second communication characteristics information to determine, for each of the slave communication devices 30, whether the wireless communication between the master communication device 20 and the plurality of slave communication devices 30 is normal or abnormal, regarding each of the first and second master communication devices 20A and 20B. Then, in case that the self-diagnosis unit 12 of the management device 10 also determines, by using the PER, that at least one slave communication device 30 has an abnormality in the wireless communication abnormality determination for each of the slave communication devices 30, transition to the abnormal position finalization mode is made. Therefore, the management device 10 performs the abnormal position finalization mode process only when there is a high possibility that some kind of abnormality has occurred in the communication system 100.
Next, the details of the abnormal position finalization mode process is described with reference to the flowchart of
The abnormal position finalization unit 13 of the management device 10 first determines whether or not the master communication device 20 has established connections with all of the slave communication devices 30 in step S505. When the master communication device 20 has not established connections with all of the slave communication devices 30, the process proceeds to step S510. In step S510, the abnormal position finalization unit 13 of the management device 10 determines whether or not there is a connected slave communication device 30 having an established connection. When there is a connected slave communication device 30, the process proceeds to step S515. On the other hand, when there is no connected slave communication device 30, the process proceeds to step S590 in the flowchart of
In step S515, since the abnormal position finalization unit 13 of the management device 10 cannot obtain the communication characteristics of the unconnected slave communication device 30, the abnormal position finalization unit 13 sets the obtained communication characteristics as a default determination value. The default determination value is a value that is set so that communication failure is determinable in steps S530 and S555, which is described later.
In step S520, which is performed subsequently to (a) step S515 or (b) when it is determined in step S505 that the master communication device 20 has established connections with all of the slave communication devices 30, the abnormal position finalization unit 13 of the management device 10 instructs the first and second master communication devices 20A and 20B to communicate with all connected slave communication devices 30A to 30E on multiple frequency channels and to obtain RSSIs. In response to this instruction, wireless communication on multiple frequency channels is performed for all combinations of the master communication devices 20 and the connected slave communication devices 30, and the RSSI of each wireless communication is obtained. Each of the obtained RSSIs is provided from the master communication device 20 to the management device 10. The multiple frequency channels may be all frequency channels, or not necessarily all but may be a second predetermined number or more of frequency channels. Further, the RSSI obtained in the self-diagnosis mode may be used in the abnormal position finalization mode without obtaining a new RSSI in the abnormal position finalization mode.
In step S525, the abnormal position finalization unit 13 of the management device 10 reads, from the storage unit 15, a reference RSSI, which is/are a reference communication characteristic or characteristics of each of multiple communication channels on which the master communication device 20 has performed communication with each of the plurality of slave communication devices 30. Then, in step S530, the abnormal position finalization unit 13 of the management device 10 determines, for each of the slave communication devices 30, whether wireless communication between the master communication device 20 and the plurality of slave communication devices 30 is normal or abnormal based on a strength of correlation between (a) an overall trend of the plurality of obtained RSSIs and (b) an overall trend of the reference RSSIs over the multiple frequency channels, in all combinations of the master communication device 20 and the slave communication devices 30. This determination process is performed in the same manner as the determination process in the self-diagnosis mode.
In step S535, the abnormal position finalization unit 13 of the management device 10 determines the abnormal position for each of the slave communication devices 30, based on the determination results of whether wireless communication between the master communication device 20 and the plurality of slave communication devices 30 is normal or abnormal by using the RSSI, which is determined for each of the first and second master communication devices 20A and 20B. A method for determining an abnormal position is described in detail below.
First, the abnormal position finalization unit 13 of the management device determines that one of the master communication devices 20 is having an abnormality when (A) it is determined that wireless communication between (a) one of the first and second master communication devices 20A and 20B and (b) the plurality of slave communication devices 30 is all abnormal, and (B) it is determined that wireless communication between (c) the other one of the first and second master communication devices 20A and 20B and (d) at least some of the plurality of slave communication devices 30 is normal.
Next, the abnormal position finalization unit 13 of the management device determines that an abnormality is occurring in a slave communication device 30 when the slave communication device 30 determined in the following two situations (a) and (b) is the same, i.e., (a) the slave communication device 30 having wireless communication abnormality in a determination of whether wireless communication between one of the first and second master communication devices 20A and 20B and the plurality of slave communication devices 30 is normal or abnormal, and (b) the slave communication device 30 having wireless communication abnormality in a determination of whether wireless communication between the other one of the first and second master communication devices 20A and 20B and the plurality of slave communication devices 30 is normal or abnormal.
Further, the abnormal position finalization unit 13 of the management device 10 determines that the communication propagation path between the first and second master communication devices 20A and 20B and the plurality of slave communication devices 30 has an abnormality, when (A) it is determined that wireless communication between (a) one of the first and second master communication devices and 20B and (b) the plurality of slave communication devices 30 is all abnormal, and (B) it is determined that wireless communication between (c) the other one of the first and second master communication devices 20A and 20B and (d) the plurality of slave communication devices 30 is all abnormal. An abnormality of the communication propagation path can occur, for example, in a situation where a radio wave shielding object intervenes in the communication propagation path.
Here, the abnormal position finalization unit 13 of the management device cannot identify the abnormal position where an abnormality is occurring in case that, (A) when an abnormality of wireless communication between the master communication device 20 and the plurality of slave communication devices 30 is determined for each of the slave communication device 30 by using the RSSI, which is the first communication characteristics information, and (B) when the determination results of wireless communication abnormality do not match among the first and second master communication devices 20A and 20B.
In step S545, the abnormal position finalization unit 13 of the management device 10 instructs the first and second master communication devices 20A and 20B to communicate with all connected slave communication devices 30A to 30E on multiple frequency channels, and to obtain the PER. In response to such an instruction, wireless communication is performed on multiple frequency channels for all combinations of the master communication device 20 and the connected slave communication devices 30, and the PER of each wireless communication (i.e., packet data communication) is obtained. The obtained PERs are provided from each of the master communication devices 20 to the management device 10. Note that the multiple frequency channels may be all frequency channels, or not necessarily all but may be a second predetermined number or more of frequency channels. Also, obtaining the PER in step S545 may be simultaneously performed with obtaining the RSSI in step S520 described above. Alternatively, the PER obtained in the self-diagnosis mode may be used in the abnormal position finalization mode.
In step S550, the abnormal position finalization unit 13 of the management device 10 reads, from the storage unit 15, the reference PER, which is/are a reference communication characteristic or characteristics of each of the multiple frequency channels when the master communication device 20 has performed communication with each of the plurality of slave communication devices 30 on the multiple frequency channels. Then, in step S555, the abnormal position finalization unit 13 of the management device 10 determines, for each of the slave communication devices 30, whether wireless communication between the master communication device 20 and the plurality of slave communication devices 30 is normal or abnormal, based on the strength of the correlation between (a) the overall trend of the obtained PERs on the multiple frequency channels, and (b) the overall trend of the reference PERs, in all combinations of the master communication device 20 and the slave communication devices 30.
In step S560, the abnormal position finalization unit 13 of the management device 10 determines the abnormal position for each of the slave communication devices 30, based on the determination results of whether the wireless communication between the master communication device 20 and the plurality of slave communication devices 30 is normal or abnormal by using the PER, which is determined for each of the first and second master communication devices 20A and 20B. The determination method of the abnormal position is the same as the determination method of step S535.
In such manner, by considering the determination results of whether the wireless communication is normal or abnormal with the plurality of slave communication devices 30 for each of the first and second master communication devices 20A and 20B, the abnormal position finalization unit 13 of the management device 10 can accurately determine which position has an abnormality among (a) the first and second master communication devices 20A and 20B, (b) the plurality of slave communication devices 30, and (c) the communication propagation path between the master communication device 20 and the plurality of slave communication devices 30.
In addition, when the abnormal position finalization unit 13 of the management device 10 cannot identify the abnormal position from wireless communication abnormality determination for each of the slave communication devices 30, based on the determination results of whether the wireless communication between the master communication device 20 and the plurality of slave communication devices 30 is normal or abnormal by using the RSSI, which is determined for each of the first and second master communication devices 20A and 20B, the abnormal position finalization unit 13 of the management device 10 attempts to identify an abnormal position based on the determination results of whether the wireless communication with the communication devices 30 is normal or abnormal for each of the slave communication devices 30 by using the PER, which is determined for each of the first and second master communication devices 20A and 20B. Therefore, the possibility of identifying the abnormal position is raised. However, regardless of the success or failure of the abnormal position identification process using the RSSI, the abnormal position identification process using the PER may be performed. Then, in case that an abnormal position is identified in either one of the two abnormal position identification processes, the identified position may be considered as an abnormal position where an abnormality is occurring. Alternatively, when the identified abnormal positions of both abnormal position determination processes match with each other, the identified position may be considered as an abnormal position where an abnormality is occurring.
When it is determined in step S540 or S565 that the abnormal position has been identified, the process proceeds to step S570 in the flowchart of
In step S570, the abnormal position finalization unit 13 of the management device 10 reads a communication NG record from the communication NG recorders 23 of the first and second master communication devices 20A and 20B. The abnormal position finalization unit 13 of the management device 10 can obtain a combination between the master communication device and the slave communication device having communication abnormality from the communication NG record. In step S575, the abnormal position finalization unit 13 of the management apparatus 10 determines whether or not the communication NG record exists based on the read communication NG record. When the communication NG record exists, the abnormal position finalization unit 13 of the management device 10 proceeds to the process of step S580. When the communication NG record does not exist, the abnormal position finalization unit 13 of the management device 10 proceeds to the process of step S590.
In step S580, it is determined whether or not (a) the combination of the master communication device and the slave communication device having communication abnormality according to the communication NG record and (b) the abnormal position determined in the abnormal position finalization mode match with each other. In other words, it is determined whether the combination between the master communication device and the slave communication device having communication abnormality is consistent with the abnormal position determined at the abnormal position finalization mode. For example, when (a) communication with all of the slave communication devices 30 is recorded as abnormal in the communication NG record of one of the master communication devices 20, and (b) the abnormal position determined in step S535 or step S560 is the one of the master communication devices 20 itself, it can be determined that the combination of the master communication device and the slave communication device having communication abnormality according to the communication NG record matches (or is consistent with) the abnormal position determined by the abnormal position finalization mode. Also, when (a) the communication with a specific slave communication device 30 is recorded as abnormal in the communication NG records of the first and second master communication devices 20A and 20B, and (b) the abnormal position determined in step S535 or step S560 is the specific slave communication device 30 itself, it can be determined that the combination of the master communication device and the slave communication device having communication abnormality according to the communication NG record matches (or is consistent with) the abnormal position determined in the abnormal position finalization mode.
When it is determined in step S580 that the combination of the master communication device and the slave communication device having communication abnormality according to the communication NG record matches the abnormal position determined in the abnormal position finalization mode, the process proceeds to step S585 to notify a user or an administrator of the abnormal position. On the other hand, when it is determined in step S580 that the combination of the master communication device and the slave communication device having communication abnormality according to the communication NG record does not match the abnormal position determined in the abnormal position finalization mode, the process proceeds to step S590. In step S590, since the abnormal position where an abnormality is occurring cannot be identified, the user or the administrator is notified of the abnormality occurring over the entire communication system 100.
The present disclosure is explained with a preferred embodiment as described above. However, the present disclosure is not limited to the above-mentioned embodiment, and may be variously modified within the spirit and scope of the present disclosure.
For example, in the embodiment described above, the communication system 100 using two master communication devices 20 has been described. However, the number of master communication devices 20 may be three or more. Alternatively, the number of master communication devices 20 may be one when the position of an abnormality is not accurately identified.
Further, in the above-described embodiment, RSSI is used as the first communication characteristics information and PER is used as the second communication characteristics information. However, PER may be used as the first communication characteristics information and RSSI may be used as the second communication characteristics information. Furthermore, communication characteristic information other than RSSI and PER may also be used.
Furthermore, in the above-described embodiment, the master communication device 20 and the plurality of slave communication devices 30 perform wireless communication for obtaining RSSI and PER in the self-diagnosis mode and in the abnormal position finalization mode, respectively. However, wireless communication for obtaining RSSI and PER may be shared among the self-diagnosis mode and the abnormal position finalization mode.
In the above-described embodiment, an example has been described in which the management device 10 performs the self-diagnosis mode first, and then performs the abnormal position finalization mode when an abnormality in wireless communication is determined in the self-diagnosis mode. However, the management device 10 may perform only the self-diagnosis mode, and notify the user or the like of the result when an abnormality in wireless communication is determined in the self-diagnosis mode. Alternatively, the management device 10 may perform the abnormal position finalization mode from the beginning without performing the self-diagnosis mode.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2022-086240 | May 2022 | JP | national |
