Communication devices, programs, and communication methods

Abstract

To provide a communication device, program, and communication method that can accurately detect a fault location between communication devices constituting a wireless multi-hop network.SOLUTION: A communication device that synchronizes communication timing includes: a transmitting unit that transmits a packet including a serial number indicating the communication timing and a transmission / reception time; a receiving unit that receives the packet transmitted from a communication partner; a calculation unit that calculates upstream communication time, downstream communication time, and internal processing time to the communication partner on the basis of the received packet and the received serial number and transmission time to calculate a measured response time from the communication partner; a theoretical value calculation unit that calculates a theoretical value of the response time with the communication partner; and an abnormality detection unit that compares the measured response time with the theoretical response time to detect an abnormality in the communication state with the communication partner.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] Embodiments of the present invention relate to a communication device, a program, and a communication method. [Background technology]

[0002] In recent years, there has been a growing societal need for communication devices that can realize long-distance, low-power wireless multi-hop networks. This technology transmits sensor data and other information between communication devices in a bucket-brigade fashion, enabling the collection of data from remote locations. This technology is advantageous because it can collect data even in locations without power, power lines, or communication lines. Such communication devices are required to have a function to confirm receipt and acknowledgment in two-way communication.

[0003] Patent Document 1 discloses a communication device that performs congestion control in two-way communication while reducing the load on the computer by utilizing an acknowledgment function of the communication device. Patent Document 2 discloses a communication device that notifies the appropriate ACK bit when transmitting data in both up and down directions in a wireless multi-hop network. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2006-254383 [Patent Document 2] Japanese Patent Publication No. 2020-39038 [Overview of the project] [Problems that the invention aims to solve]

[0005] However, communication devices that require TSCH (Time Synchronized Channel Hopping) technology and high power efficiency have significantly different communication times depending on the communication path. Therefore, it is difficult to accurately detect which communication devices have experienced a failure and when.

[0006] The present invention has been made in view of the above, and an object thereof is to accurately detect a failure location between communication devices constituting a wireless multi-hop network.

Means for Solving the Problems

[0007] The communication device of the embodiment is Configure a wireless multi-hop network that communicates using time-division multiplexing. a communication device, The time-division multiplexing scheme used in the aforementioned wireless multi-hop network a transmission unit that transmits a packet including a serial number indicating communication timing and a transmission / reception time; via the aforementioned wireless multi-hop network a reception unit that receives the packet transmitted from a communication partner; a calculation unit that calculates an upstream communication time, a downstream communication time, and an internal processing time with respect to the communication partner based on the received packet, the received serial number, and the transmission time, and calculates a measured value of the response time from the communication partner; a theoretical value calculation unit that calculates a theoretical value of the response time between the communication device and the communication partner; and an abnormality detection unit that compares the measured value of the response time with the theoretical value of the response time and detects an abnormality in the communication state between the communication device and the communication partner.

Brief Description of the Drawings

[0008] [Figure 1] FIG. 1 is a diagram showing a configuration example of a communication system according to a first embodiment. [Figure 2] FIG. 2 is a block diagram showing a functional configuration of a communication device. [Figure 3] FIG. 3 is a sequence diagram showing a flow of abnormality detection processing for packet communication between communication devices. [Figure 4] FIG. 4 is a flowchart showing a flow of abnormality detection processing in step S30. [Figure 5] FIG. 5 is a sequence diagram showing a flow of abnormality detection processing for packet communication between communication devices in a second embodiment. [Figure 6] FIG. 6 is a flowchart showing a flow of reception processing in step S50. [Figure 7]Figure 7 is a flowchart showing the flow of the anomaly detection process in step S60. [Figure 8] Figure 8 is a sequence diagram showing the flow of anomaly detection processing related to packet communication between communication devices in the third embodiment. [Figure 9] Figure 9 is a flowchart showing the flow of the anomaly detection process in step S80. [Modes for carrying out the invention]

[0009] (First Embodiment) Figure 1 shows an example of the configuration of a communication system according to the first embodiment. As shown in Figure 1, the communication system of this embodiment includes a concentrator 200 (an example of an aggregation device) and a plurality of communication devices 1001 to 100 13 It is equipped with the following features.

[0010] Multiple communication devices 1001-100 13 Each transmits sensor data acquired by a sensor (or built-in sensor) connected via a data logger to the concentrator 200. Multiple communication devices 1001-100 13 Since they can have similar configurations, they may simply be referred to as communication device 100 when there is no need to distinguish between them. The number of communication devices 100 is not limited to 13, but can be any number.

[0011] The concentrator 200 is a device (aggregation device) that aggregates sensor data transmitted from each of the multiple communication devices 100.

[0012] Concentrator 200 and communication devices 1001-100 13 This constitutes a wireless multi-hop network. Communication within the wireless multi-hop network is controlled, for example, by time-division multiplexing. Any wireless communication method can be used, but for example, wireless communication methods such as IEEE 802.11 and IEEE 802.15.4 can be applied.

[0013] The concentrator 200 may be connected to network 300 in addition to the wireless multi-hop network. Network 300 can be any type of network, such as a wide-area network like the internet, a wide-area closed network, or a local network such as an enterprise network.

[0014] The connection between the concentrator 200 and the network 300 may be a wired connection using an Ethernet® cable or optical fiber, or a wireless connection using a mobile phone network or satellite link. Connection to the network 300 is not mandatory; the concentrator 200 and communication devices 1001-100 are also connected. 13 The communication system may consist solely of a wireless multi-hop network composed of the above.

[0015] The network 300 may also be connected to a server device, for example, that collects sensor data from multiple concentrators 200 and performs processing using the collected sensor data.

[0016] Here, we will explain the overview of the sensor data collection process using the communication system of this embodiment.

[0017] A data logger is connected to the communication device 100. A sensor is further connected to the data logger. The communication device 100 obtains new sensor data from the data logger, for example, by polling. At this time, the communication device 100 obtains the sensor data itself and the sensing time data for that sensor data. The sensing time is, for example, the time when the sensor data is stored in the data logger, but is not limited to this. For example, if the sensor is preheated, the sensing time may be the time when preheating started. Preheating is, for example, a process in which the sensor is heated for a certain period of time while power is supplied to the sensor before obtaining data from the sensor. For example, suppose preheating starts at 10:00:00, is completed at 10:00:20, and the time when the sensor data is stored in the data logger is 10:00:20. In this case, 10:00:00 is stored in the data logger as the sensing time.

[0018] The communication device 100 needs to transmit data corresponding to these two types of data (sensor data and sensing time) wirelessly, but it is desirable to reduce the amount of data as much as possible. For example, it is desirable to reduce the amount of data indicating the sensing time. In the following, data in a format that represents a time used in daily life (actual time as described later), such as "2021 / 08 / 23 11:30:00.000", may be referred to as time data.

[0019] In this embodiment, the communication device 100 transmits, instead of time data, a sequential number (a number indicating the communication timing) already used within the wireless multi-hop network to realize time-division multiplexing communication, as data indicating the sensing time.

[0020] As a time-division multiplexing scheme, for example, TSCH (Time-Slotted Channel Hopping) can be applied. Sequential numbers indicating communication timing include, for example, the time slot number (ASN: Absolute Slot Number), slot frame number, and superframe number.

[0021] For example, the communication device 100 polls the data logger at the beginning of each time slot to check if new sensor data has been obtained. If new data exists, the communication device 100 transmits the obtained sensor data wirelessly along with the current serial number.

[0022] Furthermore, when relaying sensor data transmitted from another communication device 100 (an example of an external communication device) to the concentrator 200, the communication device 100 may transmit sensor data with the same serial number all at once. Specifically, the serial number is included only once in the message transmitted wirelessly, and a message is generated that associates multiple sensor data with that serial number. This further reduces the amount of data transmitted.

[0023] If the data logger's time is significantly off for any reason, a configuration that transmits the time data directly may make it unclear when the sensor data was actually stored. However, with a configuration that transmits a sequential number as data representing the sensing time, as in this embodiment, the correct time when the sensor data was stored can be determined by converting the received sequential number into a time.

[0024] For example, suppose a data logger is configured to perform sensing at 0 and 30 minutes past the hour and store the sensor data in an internally provided storage medium (hereinafter referred to as internal memory). If the time managed by the data logger is off by 2 minutes, even if sensing actually occurs at 2 and 32 minutes past the hour, the data logger cannot know that the time has shifted. Therefore, the data logger transmits the sensor data associated with time data indicating 0 or 30 minutes past the hour. A device that receives the sensor data associated with time data indicating 0 or 30 minutes past the hour cannot know that the actual sensing time was 2 or 32 minutes past the hour.

[0025] On the other hand, according to this embodiment, a serial number indicating the communication timing according to the communication method used in the wireless multi-hop network is transmitted instead of time data. Therefore, if the polling interval (an example of a specified time interval) or the time interval represented by the serial number indicating the communication timing (e.g., time slot length) is set appropriately, the error between the time corresponding to the serial number and the actual sensing time can be minimized. For example, if the polling interval or the time interval represented by the serial number indicating the communication timing is 30 seconds, the error between the transmitted sensing time and the actual sensing time can be kept within 30 seconds.

[0026] Next, the functional configuration of the communication device 100 will be described.

[0027] Figure 2 is a block diagram showing the functional configuration of the communication device 100. As illustrated in Figure 2, the communication device 100 includes a transmitting unit 101, a receiving unit 102, a storage unit 103, and a control unit 107.

[0028] The transmitting unit 101 transmits data to other communication devices 100 and concentrators 200 using a predetermined communication interface. The transmitting unit 101 sends a packet containing a serial number and transmission / reception time to the other communication devices 100 and concentrators 200 that it is communicating with. In addition, the transmitting unit 101 also transmits additional information such as network information (such as the ID of the communication device 100) and sensor data.

[0029] The receiving unit 102 receives data transmitted from another communication device 100 using a predetermined communication interface. The receiving unit 102 receives packets transmitted from the other communication device 100 that is the communication partner.

[0030] The predetermined communication interface is a communication interface that communicates via a wireless multi-hop network equipped with a communication method that includes at least one of the following: a 920MHz band wireless communication method, a PLC communication method, a 4G / LTE communication method, a 5G communication method, or a WiMAX communication method. The predetermined communication interface is implemented, for example, by a wireless chip. The predetermined communication interface enables communication between the communication device 100 and other communication devices 100 and concentrators 200.

[0031] The storage unit 103 stores various types of information (various programs, various data) and is implemented using semiconductor memory elements such as RAM (Random Access Memory), ROM (Read Only Memory), flash memory, or a hard disk. When the transmission unit 101 transmits, the storage unit 103 stores the serial number and the transmission time. The storage unit 103 also stores the program of the communication device 100.

[0032] The control unit 107 performs various calculation processes and is implemented, for example, by a CPU (Central Processing Unit). The control unit 107, through the operation of the CPU according to a program, has a functional configuration that includes, for example, a calculation unit 104, a theoretical value calculation unit 105, and an anomaly detection unit 106.

[0033] The calculation unit 104 calculates three things based on the received packets and the data stored in the storage unit 103: the uplink communication time, the downlink communication time, and the internal processing time of the communication device 100, and then calculates a measured value of the response time from the communication partner.

[0034] The theoretical value calculation unit 105 calculates the theoretical value of the response time.

[0035] The anomaly detection unit 106 compares the theoretical value of the response time with the measured value of the response time, and detects that some kind of anomaly has occurred in the communication state if, for example, there is a large discrepancy between the theoretical value of the response time and the measured value of the response time.

[0036] Next, we will explain the flow of abnormality detection processing related to packet communication between communication devices 100.

[0037] Figure 3 is a sequence diagram showing the flow of abnormality detection processing related to packet communication between communication devices 100. As an example, Figure 3 shows the sequence between communication device 1002, which is the root communication device, and communication device 1006.

[0038] First, communication device 1002, which acts as the root communication device, sends packet 1 containing serial number 1 to communication device 1006 (step S201). In step S201, communication device 1002 also sends additional information such as network information (such as the ID of communication device 100) and sensor data, in addition to serial number 1.

[0039] Before or after transmitting packet 1, the communication device 1002 stores the sequence number 1 and the transmission time t0 in the storage unit 103 of the communication device 1002 (step S202). The transmission timing of packet 1 may be a timing (slot) agreed upon by each communication device 100, as disclosed in, for example, Patent Document 2.

[0040] When communication device 1006 receives packet 1 from communication device 1002, it creates packet 2 containing the serial number 1 and the data of the reception time t1 and transmission time t2 of communication device 1006, and transmits it to communication device 1002 (step S203). In step S203, communication device 1006 also transmits additional information such as network information (such as the ID of communication device 100) and sensor data in addition to the serial number 1.

[0041] Before or after transmitting packet 2, the communication device 1006 stores the serial number 1 and the transmission time t2 of the communication device 1006 in the storage unit 103 of the communication device 1006 (step S204).

[0042] When communication device 1002 receives packet 2 from communication device 1006, it performs anomaly detection processing (step S30).

[0043] Next, we will explain the flow of the anomaly detection process in step S30.

[0044] Figure 4 is a flowchart showing the flow of the anomaly detection process in step S30. As shown in Figure 4, when communication device 1002, which is the root communication device, receives packet 2 from communication device 1006, it starts the processing flow shown in Figure 4 (step S301).

[0045] After receiving the data, the calculation unit 104 of the communication device 1002 obtains the transmission time t0 associated with serial number 1 from the storage unit 103 of the communication device 1002 (step S302).

[0046] If the calculation unit 104 of the communication device 1002 successfully obtains the transmission time t0 (Yes in step S302), it calculates the internal processing time d0 (d0 = t2 - t1) of the communication device 1006 from the reception time t1 and transmission time t2 (step S303).

[0047] Furthermore, if the calculation unit 104 of the communication device 1002 fails to obtain the transmission time t0 (No. in step S302), it terminates the processing in step S30.

[0048] Next, the calculation unit 104 of the communication device 1002 calculates the downlink communication time d1 (d1 = t1 - t0) using the acquired transmission time t0 and the reception time t1 from the communication device 1006 (step S304).

[0049] Furthermore, the calculation unit 104 of the communication device 1002 calculates the uplink communication time d2 (d2 = t3 - t2) using the transmission time t2 of the communication device 1006 and the time t3 when packet 2 was received from the communication device 1006 (step S305).

[0050] Then, the calculation unit 104 of the communication device 1002 calculates the measured response time r0 (r0 = d0 + d1 + d2) between the communication device 1002 and the communication device 1006 by summing the calculated downlink communication time d1, uplink communication time d2, and the internal processing time d0 of the communication device 1006 (step S306).

[0051] Subsequently, the theoretical value calculation unit 105 of the communication device 1002 calculates the theoretical value s0 of the response time between the communication device 1002 and the communication device 1006 (step S307).

[0052] Finally, the anomaly detection unit 106 of the communication device 1002 compares the theoretical value s0 of the response time with the measured value r0 of the response time (step S308).

[0053] The anomaly detection unit 106 of the communication device 1002 can detect that some kind of anomaly has occurred in the communication state by comparing the theoretical value s0 of the response time with the measured value r0 of the response time, for example, if there is a large discrepancy.

[0054] Thus, according to the communication device of the first embodiment, if the communication device can uniquely determine the timing of transmission, it is possible to calculate the theoretical value s0 of the response time in advance. By comparing this calculated value with the measured value r0 of the response time, it is possible to detect, for example, that there is some kind of abnormality in the communication state if there is a large discrepancy. In other words, according to this embodiment, it is possible to accurately detect the location of a fault between communication devices that constitute a wireless multi-hop network.

[0055] In this embodiment, the theoretical value s0 of the response time is calculated, but this is not the only method. Instead of calculating the theoretical value s0, the measured response time r0 calculated from previously measured values ​​may be compared with the calculated measured response time. This also allows for the detection of changes in communication conditions.

[0056] (Second Embodiment) Next, a second embodiment will be described.

[0057] The second embodiment differs from the first embodiment, which is a sequence for two-party communication (when the number of hops is 1), in that it is a sequence applied to vertical communication (when the number of hops is 2). In the following description of the second embodiment, the parts that are the same as those of the first embodiment will be omitted, and the parts that differ from the first embodiment will be described.

[0058] Figure 5 is a sequence diagram showing the flow of abnormality detection processing related to packet communication between communication devices 100 in the second embodiment. As an example, Figure 5 shows communication device 1002 which is the root communication device, communication device 1006, and communication device 100 10 This shows the sequence between and . In this embodiment, the case with two hops is described, but the number of hops may be two or more.

[0059] First, the communication device 1002, which acts as the root communication device, transmits packet 1, including serial number 1, to the communication device 1006, similar to the first embodiment (step S201). In step S201, the communication device 1002 also transmits additional information such as network information (such as the ID of communication device 100) and sensor data, in addition to serial number 1.

[0060] Similar to the first embodiment, the communication device 1002 stores the sequence number 1 and the transmission time t0 in its storage unit 103 before or after the transmission of packet 1 (step S202). The transmission timing of packet 1 may be a timing (slot) agreed upon by each communication device 100, as disclosed in, for example, Patent Document 2.

[0061] When communication device 1006 receives packet 1 from communication device 1002, it creates packet 2 containing data including serial number 1, the reception time t1 and transmission time t2 of communication device 1006, and communication device 1002 and communication device 100 10On the other hand, it transmits (step S203). In step S203, the communication device 1006 also transmits additional information such as network information (such as the ID of the communication device 100) and sensor data in addition to the serial number 1.

[0062] Similar to the first embodiment, before or after transmitting packet 2, the communication device 1006 stores the serial number 1 and the transmission time t2 of the communication device 1006 in the storage unit 103 of the communication device 1006 (step S204).

[0063] Similar to the first embodiment, when the communication device 1002 receives packet 2 from the communication device 1006, it executes an abnormality detection process (step S30). Since the abnormality detection process in step S30 is the same as that in the first embodiment, detailed description thereof is omitted.

[0064] On the other hand, when the communication device 1 10 receives packet 2 from the communication device 1006, it creates packet 3 including data of the serial number 1, the reception time t4, and the transmission time t5 of the communication device 1 10 and transmits it to the communication device 1006 (step S401). In step S401, the communication device 1 10 also transmits additional information such as network information (such as the ID of the communication device 100) and sensor data in addition to the serial number 1.

[0065] The communication device 1 10 stores the serial number 1 and the transmission time t5 of the communication device 1 10 in the storage unit 103 of the communication device 1 10 before or after transmitting packet 3 (step S402).

[0066] When the communication device 1006 receives packet 3 from the communication device 1 10 it executes a reception process (step S50).

[0067] Next, the flow of the reception process in step S50 will be described.

[0068] Figure 6 is a flowchart showing the flow of the reception process in step S50. As shown in Figure 6, the communication device 1006 is 10 Upon receiving packet 3, the processing flow shown in Figure 6 is initiated (step S501).

[0069] After receiving the data, the calculation unit 104 of the communication device 1006 obtains the transmission time t2 associated with serial number 1 from the storage unit 103 of the communication device 1006 (step S503).

[0070] If the calculation unit 104 of the communication device 1006 successfully obtains the transmission time t2 (Yes in step S502), the communication device 100 10 From the reception time t4 and transmission time t5, the communication device 100 10 The internal processing time d3 (d3 = t5 - t4) is calculated (step S503).

[0071] Furthermore, if the calculation unit 104 of the communication device 1006 fails to obtain the transmission time t2 (No. in step S502), it terminates the reception process in step S50.

[0072] Next, the calculation unit 104 of the communication device 1006 calculates the acquired transmission time t2 and the communication device 100 10 Using the reception time t4 from the source, the downlink communication time d4 (d4 = t4 - t2) is calculated (step S504).

[0073] Furthermore, the calculation unit 104 of the communication device 1006 10 The transmission time t5 and communication device 100 10 Using the time t6 when packet 3 was received, the uplink communication time d5 (d5 = t6 - t5) is calculated (step S505).

[0074] Then, the calculation unit 104 of the communication device 1006 calculates the communication device 100 10 By summing the internal processing time d3, the downlink communication time d4, and the uplink communication time d5, the communication device 1006 and communication device 100 10The measured response time r1 (r1=d3+d4+d5) between the two is calculated (step S506), and the process in step S50 is terminated.

[0075] Returning to Figure 5, when the communication device 1006 completes the processing in step S50, the serial number 1 and the communication device 100 10 Reception time t6 from, transmission time t7 from communication device 1006, communication device 100 10 Reception time t4, communication device 100 10 The transmission time t5 and response time r1 are included in packet 2-1 and broadcast, and sent to the root communication device, communication device 1002 (step S403).

[0076] Before or after transmitting packet 2-1, the communication device 1006 stores the serial number 1 and the transmission time t7 of the communication device 1006 in the storage unit 103 of the communication device 1006 (step S404).

[0077] Furthermore, the communication device 100 10 The communication device 1006 receives packet 2-1. However, the communication device determines whether or not the received packet was created by itself based on network information, that is, whether or not it is addressed to itself. Therefore, the communication device 100 10 The system determines that packet 2-1 is not addressed to itself, and therefore does not process it.

[0078] Meanwhile, when communication device 1002 receives packet 2-1 from communication device 1006, it performs anomaly detection processing (step S60).

[0079] Next, we will explain the flow of the anomaly detection process in step S60.

[0080] Figure 7 is a flowchart showing the flow of the anomaly detection process in step S60. As shown in Figure 7, when the communication device 1002, which is the root communication device, receives packet 2-1 from the communication device 1006, it starts the processing flow shown in Figure 7 (step S601).

[0081] After receiving the data, the calculation unit 104 of the communication device 1002 obtains the transmission time t0 associated with serial number 1 from the storage unit 103 of the communication device 1002 (step S602).

[0082] If the calculation unit 104 of the communication device 1002 successfully obtains the transmission time t0 (Yes in step S602), the communication device 100 10 The reception time t4 and the communication device 100 10 The transmission time t5 and from t5 to communication device 100 10 The internal processing time d3 (d3 = t5 - t4) is calculated (step S603).

[0083] Furthermore, if the calculation unit 104 of the communication device 1002 fails to obtain the transmission time t0 (No. in step S602), it terminates the processing in step S60.

[0084] Next, the calculation unit 104 of the communication device 1002 calculates the acquired transmission time t0 and the communication device 100 10 Using the reception time t4 from the source, the downlink communication time d6 (d6 = t4 - t0) is calculated (step S604).

[0085] Furthermore, the calculation unit 104 of the communication device 1002 10 The transmission time t5 and communication device 100 10 Using the time t8 when packet 2-1 containing the information was received, the uplink communication time d7 (d7 = t8 - t5) is calculated (step S605).

[0086] Then, the calculation unit 104 of the communication device 1002 calculates the downlink communication time d6 and the uplink communication time d7, and the communication device 100 10 By summing the internal processing times d3, the root communication device, communication device 1002, and communication device 100 10 The measured response time r2 (r2 = d3 + d6 + d7) between the two points is calculated (step S606).

[0087] Subsequently, the theoretical value calculation unit 105 of the communication device 1002 calculates the theoretical value of the communication device 1002 and the communication device 100 10The theoretical value s2 of the response time between (step S607) is calculated.

[0088] Then, the anomaly detection unit 106 of the communication device 1002 compares the theoretical value s2 of the response time with the measured value r2 of the response time (step S608).

[0089] The anomaly detection unit 106 of the communication device 1002 can detect that some kind of anomaly has occurred in the communication state by comparing the theoretical value s2 of the response time with the measured value r2 of the response time, for example, if there is a large discrepancy.

[0090] Furthermore, the calculation unit 104 of the communication device 1002 communicates with the communication device 1006 and the communication device 100 10 The theoretical value s1 of the response time between (step S609) is calculated.

[0091] Finally, the anomaly detection unit 106 of the communication device 1002 compares the theoretical value s1 of the response time with the measured value r1 of the response time (step S610).

[0092] The anomaly detection unit 106 of the communication device 1002 can detect that some kind of anomaly has occurred in the communication state by comparing the theoretical value s1 of the response time with the measured value r1 of the response time, for example, if there is a large discrepancy.

[0093] Thus, according to the communication device of the second embodiment, if the communication device can uniquely determine the timing of transmission, it is possible to calculate the theoretical value s0 of the response time in advance. By comparing this calculated value with the measured value r0 of the response time, it is possible to detect, for example, that there is some kind of abnormality in the communication state if there is a large discrepancy. In other words, according to this embodiment, it is possible to accurately detect the location of a fault between communication devices that constitute a wireless multi-hop network.

[0094] In this embodiment, the theoretical value s0 of the response time is calculated, but this is not the only method. Instead of calculating the theoretical value s0 of the response time, the calculated value r0 of the response time may be compared with a previously measured value of the response time. This also allows for the detection of changes in the communication status.

[0095] Furthermore, in this embodiment, the communication device 1006 sent packets in both the uplink and downlink directions, thereby connecting the root communication device, communication device 1002, and communication device 100 10 Packets will reach both the uplink and downlink devices. When the transmitting unit 101 sends packets in both the uplink and downlink directions in this manner, the calculation unit 104 calculates the uplink communication time, downlink communication time and internal processing time for the communication partner, and calculates a measured response time from the communication partner. In other words, the communication device 1002, which is the root communication device, can quickly calculate the uplink and downlink communication time between communication device 1002 and communication device 1006, as well as the internal processing time of communication device 1006, by utilizing the received packets.

[0096] (Third embodiment) Next, a third embodiment will be described.

[0097] The third embodiment differs from the second embodiment in that the process of calculating the uplink and downlink communication times, internal processing time, and determining the measured response time is performed solely by the root communication device. In the following description of the third embodiment, the description of parts that are the same as those of the first or second embodiment will be omitted, and the parts that differ from the first or second embodiment will be described.

[0098] Figure 8 is a sequence diagram showing the flow of abnormality detection processing related to packet communication between communication devices 100 in the third embodiment. As an example, Figure 8 shows communication device 1002 which is the root communication device, communication device 1006, and communication device 100 10 This shows the sequence between and . In this embodiment, the case with two hops is described, but the number of hops may be two or more.

[0099] As shown in Figure 8, in this embodiment, the communication device 1006 is the communication device 100 10 Even if packet 3 transmitted in step S401 is received, the process of step S50 described in the second embodiment is not executed, and the process proceeds to step S403.

[0100] Furthermore, in this embodiment, when the communication device 1002, which acts as the root communication device, receives packet 2-1 from the communication device 1006, it performs an anomaly detection process (step S80).

[0101] Next, we will explain the flow of the anomaly detection process in step S80.

[0102] Figure 9 is a flowchart showing the flow of the anomaly detection process in step S80. As shown in Figure 9, when communication device 1002, which is the root communication device, receives packet 2-1 from communication device 1006, it starts the processing flow shown in Figure 9 (step S601).

[0103] After receiving the data, the calculation unit 104 of the communication device 1002 obtains the transmission time t0 associated with serial number 1 from the storage unit 103 of the communication device 1002 (step S602).

[0104] If the calculation unit 104 of the communication device 1002 successfully obtains the transmission time t0 (Yes in step S602), the communication device 100 10 The reception time t4 and the communication device 100 10 The transmission time t5 and from t5 to communication device 100 10 The internal processing time d3 (d3 = t5 - t4) is calculated (step S603).

[0105] Furthermore, if the calculation unit 104 of the communication device 1002 fails to obtain the transmission time t0 (No. in step S602), it terminates the processing in step S60.

[0106] Next, the calculation unit 104 of the communication device 1002, similar to the process of step S504 described in Figure 6 of the second embodiment, obtains the transmission time t2 of the communication device 1006 and the communication device 100 10 Using the reception time t4 from the source, the downlink communication time d4 (d4 = t4 - t2) is calculated (step S804).

[0107] Furthermore, the calculation unit 104 of the communication device 1006 performs the same processing as in step S505 described in Figure 6 of the second embodiment, 10 The transmission time t5 and communication device 100 10 Using the time t6 when packet 3 was received, the uplink communication time d5 (d5 = t6 - t5) is calculated (step S805).

[0108] Then, the calculation unit 104 of the communication device 1006 calculates the communication device 100 in the same way as the process in step S506 described in Figure 6 of the second embodiment. 10 By summing the internal processing time d3, the downlink communication time d4, and the uplink communication time d5, the communication device 1006 and communication device 100 10 The measured response time r1 (r1 = d3 + d4 + d5) between the two points is calculated (step S806).

[0109] The subsequent steps S604 to S610 are the same as in the second embodiment, so a detailed explanation will be omitted.

[0110] Thus, according to the communication device of the third embodiment, if the communication device can uniquely determine the timing of transmission, it is possible to calculate the theoretical value s0 of the response time in advance. By comparing this with the measured value r0 of the calculated response time, it is possible to detect, for example, that there is some kind of abnormality in the communication state if there is a large discrepancy.

[0111] In this embodiment, the theoretical value s0 of the response time is calculated, but this is not the only method. Instead of calculating the theoretical value s0 of the response time, the calculated value r0 of the response time may be compared with a previously measured value of the response time. This also allows for the detection of changes in the communication status. In other words, according to this embodiment, fault locations between communication devices constituting a wireless multi-hop network can be accurately detected.

[0112] Furthermore, in this embodiment, the communication device 1006 sent packets in both the uplink and downlink directions, thereby connecting the root communication device, communication device 1002, and communication device 100 10 Packets will reach both the uplink and downlink devices. When the transmitting unit 101 sends packets in both uplink and downlink directions, and is the root communication device, the calculation unit 104 calculates the uplink communication time, downlink communication time and internal processing time for the communication partner, and calculates a measured value of the response time from the communication partner. In other words, the communication device 1002, which is the root communication device, can quickly calculate the uplink and downlink communication time between the communication device 1002 and the communication device 1006, as well as the internal processing time of the communication device 1006, by utilizing the received packets.

[0113] Furthermore, according to this embodiment, since the amount of information included in the packet is less compared to the first or second embodiment, the amount of traffic can be reduced.

[0114] While several embodiments of the present invention have been described, these embodiments are presented as examples only and are not intended to limit the scope of the invention. These novel embodiments can be carried out in a variety of other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their variations are included in the scope and spirit of the invention, as well as in the claims of the invention and its equivalents. [Explanation of Symbols]

[0115] 100 Communication devices 101 Transmitter 102 Receiving Unit 103 Storage section 104 Calculation section 105 Theoretical Value Calculation Unit 106 Anomaly detection unit

Claims

1. A communication device comprising a wireless multi-hop network that communicates using a time-division multiplexing scheme, A transmitting unit that transmits packets including a sequential number indicating the communication timing and transmission / reception time using the time-division multiplexing scheme used in the aforementioned wireless multi-hop network, A receiving unit that receives the packet transmitted from the communication partner via the aforementioned wireless multi-hop network, A calculation unit calculates the uplink communication time, downlink communication time, and internal processing time to the communication partner based on the received packet, the received serial number, and the transmission time, and calculates a measured value of the response time from the communication partner. A theoretical value calculation unit that calculates a theoretical value of the response time between the communication partner, An anomaly detection unit compares the measured value of the response time with the theoretical value of the response time and detects an anomaly in the communication state with the communication partner, A communication device characterized by comprising:

2. The transmitting unit transmits the packet by broadcast, The receiving unit receives the packet broadcast by the communication partner. The communication device according to feature 1.

3. The aforementioned packet is further provided with a memory unit that stores a serial number and transmission time when the packet is transmitted. The calculation unit calculates the uplink communication time, downlink communication time, and internal processing time to the communication partner based on the received packet and the serial number and transmission time stored in the storage unit, and calculates the measured response time from the communication partner. The communication device according to feature 1.

4. The theoretical value calculation unit uses the previously measured response time as the theoretical value of the response time. The communication device according to feature 1.

5. The transmitting unit sends the packets in both the uplink and downlink directions. The communication device according to feature 1.

6. When the transmitting unit sends the packet in both the uplink and downlink directions, the calculation unit calculates the uplink communication time, downlink communication time, and internal processing time to the communication partner, and calculates a measured value of the response time from the communication partner. The communication device according to feature 5.

7. When the transmitting unit sends the packets in both the uplink and downlink directions, and is a root communication device, the calculation unit calculates the uplink communication time, downlink communication time and internal processing time to the communication partner, and calculates a measured value of the response time from the communication partner. The communication device according to feature 5.

8. A communication device comprising a wireless multi-hop network that communicates using a time-division multiplexing scheme, A transmitting unit that transmits packets including a sequential number indicating the communication timing and transmission / reception time using the time-division multiplexing scheme used in the aforementioned wireless multi-hop network, A receiving unit that receives the packet transmitted from the communication partner via the aforementioned wireless multi-hop network, A computer that controls a communication device equipped with A calculation unit calculates the uplink communication time, downlink communication time, and internal processing time to the communication partner based on the received packet, the received serial number, and the transmission time, and calculates a measured value of the response time from the communication partner. A theoretical value calculation unit that calculates a theoretical value of the response time between the communication partner, An anomaly detection unit compares the measured value of the response time with the theoretical value of the response time and detects an anomaly in the communication state with the communication partner, A program characterized by being designed to function as such.

9. A communication method in a communication device that constitutes a wireless multi-hop network communicating using a time-division multiplexing scheme, A transmission step in which the transmitting unit transmits a packet including a sequential number indicating the communication timing of the time-division multiplexing scheme used in the wireless multi-hop network and the transmission and reception time, A receiving step in which the receiving unit receives the packet transmitted from the communication partner via the wireless multi-hop network, The calculation unit calculates the uplink communication time, downlink communication time, and internal processing time to the communication partner based on the received packet, the received serial number, and the transmission time, and calculates a measured value of the response time from the communication partner. The theoretical value calculation unit calculates a theoretical value of the response time between the communication partner in a theoretical value calculation step, An anomaly detection step in which the anomaly detection unit compares the measured value of the response time with the theoretical value of the response time and detects an anomaly in the communication state with the communication partner, A communication method characterized by including

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