Communication device, communication system, information processing method, and program

Abstract

To provide a communication device and the like capable of suppressing a decrease in a security level of communication during a period in which correction of a shared time is executed.SOLUTION: One communication device 20 out of a plurality of communication devices 20 belonging to a mesh network 40 includes a clocking part 25 for measuring the current time, and a control signal for controlling the other communication devices 20 belonging to the mesh network 40. And an output unit 224 that outputs a control signal including time information indicating the current time measured by the clocking unit 25, in which the output unit 224 outputs a control signal including first time information indicating the current time before correction and second time information indicating the current time after correction in a target period until a predetermined time elapses after the current time measured by the clocking unit 25 is corrected.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a communication device, a communication system, an information processing method, and a program. [Background technology]

[0002] Patent Document 1 discloses a technique for synchronizing the time held by each of a plurality of communication devices belonging to a mesh network. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2023-042838 Summary of the Invention [Problem to be solved by the invention]

[0004] In a communication system that synchronizes time between multiple communication devices, such as the technology disclosed in Patent Document 1, the reliability of information exchanged between the multiple communication devices can be confirmed by adding information indicating the synchronized time to the information.

[0005] However, it takes time for the communication for correcting the synchronized time to reach the entire communication system, and for a certain period after the communication starts, the communication system will contain a mixture of communication devices that hold the time before correction and communication devices that hold the time after correction, which makes it impossible to confirm the reliability of the information based on the information indicating the time.

[0006] Therefore, the present disclosure aims to provide a communication device, a communication system, an information processing method, and a program that can suppress a decrease in the security level of communication during a period when correction of the shared time is being performed. [Means for solving the problem]

[0007] One aspect of a communication device according to the present disclosure is one of a plurality of communication devices belonging to a mesh network, the communication device comprising: a timing unit that measures the current time; and an output unit that outputs a control signal for controlling other communication devices belonging to the mesh network, the control signal including time information indicating the current time measured by the timing unit, the control signal including first time information indicating the current time before correction and second time information indicating the current time after correction, during a target period from when the current time measured by the timing unit is corrected until a predetermined time has elapsed.

[0008] Furthermore, one aspect of a communication device according to the present disclosure is one of a plurality of communication devices belonging to a mesh network, and includes: an acquisition unit that acquires a control signal including time information from another communication device of the plurality of communication devices; a timing unit that measures the current time; a determination unit that determines whether the difference between the current time measured by the timing unit and the time indicated by the time information included in the control signal acquired by the acquisition unit is within a predetermined range; and a control unit that executes control based on the control signal, provided that it is determined that the difference between the current time measured by the timing unit and the time indicated by the time information included in the control signal acquired by the acquisition unit is within the predetermined range, and the determination unit determines whether the difference between the current time before correction and the current time after correction and the time indicated by the time information included in the control signal is within the predetermined range during a target period from when the current time measured by the timing unit is corrected to when a predetermined time has elapsed.

[0009] Furthermore, one aspect of the communication system according to the present disclosure includes a plurality of communication devices, each of which operates as the communication device when transmitting information and operates as the communication device when receiving information.

[0010] Furthermore, one aspect of the information processing method according to the present disclosure is an information processing method executed by one of a plurality of communication devices belonging to a mesh network, the communication device having a timing unit that measures the current time, the information processing method including an output step of outputting a control signal for controlling other communication devices belonging to the mesh network, the control signal including time information indicating the current time measured by the timing unit, and the output step of outputting the control signal including first time information indicating the current time before correction and second time information indicating the current time after correction, during a target period from when the current time measured by the timing unit is corrected to when a predetermined time has elapsed.

[0011] Furthermore, one aspect of the information processing method according to the present disclosure is an information processing method executed by one of a plurality of communication devices belonging to a mesh network, the communication device having a timing unit that measures the current time, the information processing method including: an acquisition step of acquiring a control signal including time information from another communication device of the plurality of communication devices; a determination step of determining whether a difference between the current time measured by the timing unit and the time indicated by the time information included in the control signal acquired in the acquisition step is within a predetermined range; and a control step of executing control based on the control signal, provided that it is determined that the difference between the current time measured by the timing unit and the time indicated by the time information included in the control signal acquired in the acquisition step is within the predetermined range, wherein the determination step determines whether a difference between the current time before correction and the current time after correction and the time indicated by the time information included in the control signal is within the predetermined range during a target period from when the current time measured by the timing unit is corrected until a predetermined time has elapsed.

[0012] The present disclosure can be realized not only as the information processing method, but also as a program for causing a computer to execute the information processing method, and further as a computer-readable recording medium storing the program. [Effects of the Invention]

[0013] The communication device, communication system, information processing method, and program according to the present disclosure can suppress a decrease in the security level of communication during a period in which correction of the shared time is being performed. [Brief explanation of the drawings]

[0014] [Figure 1] FIG. 1 is a block diagram illustrating a functional configuration of a communication system according to an embodiment. [Figure 2] FIG. 2 is a diagram illustrating an example of a network configuration of a mesh network according to an embodiment. [Figure 3] FIG. 3 is a flowchart illustrating an operation of the communication device according to the embodiment to transmit a signal. [Figure 4] FIG. 4 is a flowchart illustrating an operation of the communication device according to the embodiment to receive a signal. DETAILED DESCRIPTION OF THE INVENTION

[0015] (Embodiment) Hereinafter, embodiments of a communication device, a communication system, an information processing method, and a program according to the present disclosure will be described in detail with reference to the drawings. Note that each of the embodiments described below represents a preferred specific example of the present disclosure. The numerical values, components, the arrangement and connection of the components, steps, the order of steps, and the like shown in the following embodiments are merely examples and are not intended to limit the present disclosure. Furthermore, among the components in the following embodiments, components not recited in independent claims will be described as optional components constituting a preferred embodiment.

[0016] It should be noted that the drawings are schematic diagrams and are not necessarily strict illustrations. In addition, in the drawings, substantially the same components are denoted by the same reference numerals, and overlapping descriptions may be omitted or simplified.

[0017] Furthermore, unless otherwise specified, ordinal numbers such as "first" and "second" in this disclosure do not refer to the number or order of components, etc., but are used for the purpose of avoiding confusion and distinguishing between components, etc. of the same type.

[0018] [composition] First, the configuration of a communication system according to the present embodiment will be described. Fig. 1 is a block diagram showing the functional configuration of a communication system 10 according to the embodiment. The communication system 10 includes a plurality of communication devices 20 and one or more time management devices 30.

[0019] In the communication system 10, each of the multiple communication devices 20 and one or more time management devices 30 has a wireless communication function, and the multiple communication devices 20 and one or more time management devices 30 form a mesh network 40. The mesh network 40 is an example of a wireless network.

[0020] The mesh network 40 may include devices other than the multiple communication devices 20 and one or more time management devices 30. For example, the mesh network 40 may include devices such as an environmental sensor or a projector (not shown).

[0021] For example, if the communication device 20 is a lighting device, the information transmitted through the mesh network 40 is control information for controlling the on / off or dimming of the communication device 20. Furthermore, if the communication device 20 is an environmental sensor, the measurement value (sensing information) of the environmental sensor is transmitted.

[0022] 2 is a diagram showing an example of a network configuration of a mesh network 40 according to an embodiment. Each circle in FIG. 2 corresponds to one communication device 20 or one time management device 30 (in other words, a communication node). In the example shown in FIG. 2, multiple communication devices 20 and one time management device 30 belong to the mesh network 40.

[0023] Here, we will explain the transmission of information in communication via the mesh network 40. In the mesh network 40, when information is transmitted from one communication node (also referred to as a first communication node) to another communication node (also referred to as a second communication node), the information is transmitted by, for example, a routing method, but may also be transmitted by other methods such as a flooding method.

[0024] In the mesh network 40, a communication path is set in advance that allows information to be distributed to the communication nodes belonging to the mesh network 40. When the first communication node unicasts information including the address information (destination information) of the second communication node based on the set communication path, other communication nodes belonging to the same mesh network 40 as the first communication node that receive the information further unicast the received information based on the set communication path. In other words, the other communication nodes relay the information. By repeating this relay of information within the same mesh network 40, the second communication node can receive the information transmitted by the first communication node.

[0025] In the mesh network 40, a communication path is set in advance that allows information to be distributed to the communication nodes belonging to the mesh network 40, but the communication path may be changed as appropriate depending on the radio wave strength of the communication node.

[0026] The first communication node may broadcast information including the address information (destination information) of the second communication node, and other communication nodes that receive the information and belong to the same mesh network 40 as the first communication node may relay the received information and further broadcast it. By repeating this relay of information within the same mesh network 40, the information transmitted by the first communication node reaches all communication nodes that belong to the same mesh network 40 as the first communication node. Therefore, the second communication node can receive the information transmitted by the first communication node.

[0027] Returning to Fig. 1, the communication device 20 will be described. The communication device 20 has a wireless communication function, and a plurality of communication devices 20, together with one or more time management devices 30, form a mesh network 40. The communication device 20 has a function of relaying an acquired control signal to another communication device 20 via the mesh network 40.

[0028] The communication device 20 is, for example, a lighting-related device. When the communication device 20 is a lighting device, for example, the communication device 20 is a base light that is installed on the ceiling of an indoor space and illuminates the indoor space. The communication device 20 has a function of irradiating light into the indoor space based on a control signal acquired via the mesh network 40. The form of the communication device 20 is not particularly limited, and may be a ceiling light, a downlight, a spotlight, or the like. The communication device 20 may also be a control terminal for controlling other communication devices 20. The communication device 20 as a control terminal receives, for example, a predetermined operation from a user and transmits a control signal for controlling the other communication devices 20. The communication device 20 may also be, for example, another lighting-related device such as an environmental sensor or a camera.

[0029] Specifically, the communication device 20 includes a communication unit 21, an information processing unit 22, a storage unit 23, a function unit 24, and a clock unit 25.

[0030] The communication unit 21 is a wireless communication circuit that enables the communication device 20 to perform wireless communication (more specifically, radio wave communication) with the time management device 30 and other communication devices 20. The communication unit 21 performs communication through a mesh network 40 that is configured by a plurality of communication devices 20 and one or a plurality of time management devices 30. Specifically, the communication unit 21 performs wireless communication in accordance with a communication standard such as BLE (Bluetooth (registered trademark) Low Energy) or Bluetooth (registered trademark) mesh. Note that the communication standard used by the communication unit 21 is not particularly limited. For example, in communication through the mesh network 40, a dedicated communication standard suited to the mesh network 40 (such as a communication standard customized from an existing communication standard) may be used.

[0031] The information processing unit 22 executes information processing and the like for the operation of the communication device 20. The information processing unit 22 operates the communication device 20 by, for example, controlling the function unit 24. The information processing unit 22 is realized by, for example, a microcomputer, but may also be realized by a processor or a dedicated circuit. The functions of the information processing unit 22 are realized by hardware such as a microcomputer or processor constituting the information processing unit 22 executing a computer program (software) stored in the storage unit 23. Specifically, the information processing unit 22 includes an acquisition unit 221, a control unit 222, a determination unit 223, and an output unit 224.

[0032] The acquisition unit 221 acquires a control signal.

[0033] The control unit 222 executes control based on the acquired control signal.

[0034] The determination unit 223 determines the acquired control signal.

[0035] The output unit 224 transmits the acquired control signal to the other communication device 20.

[0036] The storage unit 23 is a storage device that stores various types of information necessary for the operation of the communication device 20. The storage unit 23 is realized by, for example, a semiconductor memory or the like.

[0037] The functional unit 24 is a device for realizing the functions of the communication device 20 during operation of the communication device 20. The functional unit 24 is controlled by the information processing unit 22. When the communication device 20 is a lighting device, the functional unit 24 is, for example, a light source that irradiates white light into an indoor space to illuminate the indoor space. The functional unit 24 is realized by, for example, an LED element, but may also be realized by other light-emitting elements such as a semiconductor laser, an organic EL element, or an inorganic EL element.

[0038] The timekeeping unit 25 measures the current time. Specifically, the timekeeping unit 25 measures the current time based on information indicating the time obtained from the time management device 30. Here, the current time means the time held by each communication device 20. The current time may differ from the actual current time by a few minutes.

[0039] The time management device 30 belongs to the mesh network 40 and is a device for managing time information shared within the mesh network 40. The time management device 30 is realized, for example, by a scheduler. The time management device 30 controls the communication device 20, which is a lighting device, to a predetermined dimming state at a predetermined time based on a predetermined schedule, for example.

[0040] The time management device 30 acquires time information from, for example, an external NTP (Network Time Protocol) server, and transmits a signal for sharing the time information.

[0041] The time management device 30 may be one communication device 20 selected by the user from among a plurality of communication devices 20 belonging to the mesh network 40. Specifically, the time management device 30 includes a communication unit 31, an information processing unit 32, a memory unit 33, and a timing unit 34.

[0042] The communication unit 31 is a wireless communication circuit that enables the time management device 30 to perform wireless communication (more specifically, radio wave communication) with the communication devices 20. The communication unit 31 communicates with a plurality of communication devices 20 through the mesh network 40. Specifically, the communication unit 31 performs wireless communication in accordance with a communication standard such as BLE (Bluetooth (registered trademark) Low Energy) or Bluetooth (registered trademark) mesh. Note that the communication standard used by the communication unit 31 is not particularly limited. For example, in communication through the mesh network 40, a dedicated communication standard suited to the mesh network 40 (such as a communication standard customized from an existing communication standard) may be used.

[0043] The information processing unit 32 executes information processing and the like for the operation of the time management device 30. The information processing unit 32 is realized by, for example, a microcomputer, but may also be realized by a processor or a dedicated circuit. The functions of the information processing unit 32 are realized by hardware such as a microcomputer or processor that constitutes the information processing unit 32 executing a computer program (software) stored in the storage unit 33. Specifically, the information processing unit 32 includes an acquisition unit 321, a control unit 322, and an output unit 323.

[0044] The acquisition unit 321 acquires time information from, for example, an external NTP server.

[0045] The control unit 322 executes information processing and the like for the operation of the time management device 30 .

[0046] The output unit 323 outputs the time correction information to all communication devices 20 belonging to the mesh network 40 based on the acquired time information.

[0047] The storage unit 33 is a storage device that stores various types of information necessary for the operation of the time management device 30. The storage unit 33 is realized by, for example, a semiconductor memory or the like.

[0048] The timekeeping unit 34 measures the current time. Specifically, the timekeeping unit 34 measures the current time based on information indicating the time acquired from an external NTP server, for example.

[0049] As described above, the mesh network 40 is a wireless network to which a plurality of communication devices 20 and one or more time management devices 30 belong. A user can use a setting terminal (not shown) to set the configuration of the mesh network 40. In other words, a user can use the setting terminal to make a communication device 20 or a time management device 30 join the mesh network 40, and to make a communication device 20 or a time management device 30 belonging to the mesh network 40 leave the mesh network 40.

[0050] The setting terminal is, for example, a mobile terminal such as a smartphone, a tablet terminal, a PDA (Personal Digital Assistant), etc. The setting terminal may also be a dedicated remote controller used in the communication system 10.

[0051] The setting terminal communicates with one of the devices that make up the mesh network 40 using, for example, a communication protocol different from that of the mesh network 40. By transmitting the communication via the mesh network 40, any communication device 20 or time management device 30 can be configured.

[0052] [Operation] In a communication system 10, a plurality of communication devices 20 and one or more time management devices 30 belonging to a mesh network 40 share time information. According to such a communication system 10, by adding the shared time information to information exchanged between a plurality of communication devices 20, the reliability of the information can be confirmed, thereby improving the security level of the communication system 10. More specifically, this can prevent a replay attack (also called a reflection attack) in which an unauthorized third party eavesdrops on a legitimate control signal transmitted and received in the mesh network and retransmits the eavesdropped control signal in an attempt by the third party to control a communication device belonging to the mesh network.

[0053] Each of the multiple communication devices 20 measures the current time using the timing unit 25 based on the time information acquired from the time management device 30. The time management device 30 needs to periodically correct the shared time information by transmitting time correction information.

[0054] At this time, the time correction information is transmitted to the communication devices 20 via the mesh network 40, so it takes a certain amount of time for the time correction information to reach all of the communication devices 20. Therefore, from the start of communication for sharing the time correction information until the certain amount of time has passed, communication devices 20 that hold the time before correction and communication devices 20 that hold the time after correction will be mixed within the communication system 10, making it impossible to confirm the reliability of the information based on the information indicating the time.

[0055] In the communication system 10 according to the embodiment, the control signal transmitted between the start of communication for sharing time correction information and the elapse of a predetermined time is provided with information indicating the time before correction and information indicating the time after correction.

[0056] According to the communication system 10, even during the period when the time shared within the mesh network 40 is being corrected, it is possible to prevent the security level of communication from decreasing.

[0057] The operations of the communication device 20 in such a communication system 10 when it transmits a control signal and when it receives a control signal will be described below.

[0058] [Send Action] The following describes the operation of communication device 20 when it transmits a control signal. Fig. 3 is a flowchart illustrating the operation of communication device 20 according to the embodiment when it transmits a signal.

[0059] First, the acquisition unit 221 acquires time correction information (S11). The control unit 222 corrects the current time measured by the timing unit 25 based on the time correction information acquired by the acquisition unit 221. The time correction information may be information indicating the corrected time, or may be information indicating the difference between the time before and after correction.

[0060] The output unit 323 of the time management device 30 uses the communication unit 31 to transmit the time correction information to all communication devices 20 belonging to the mesh network 40. The time correction information is transmitted via the mesh network 40 and acquired by the acquisition unit 221 using the communication unit 21 of each of the multiple communication devices 20. The time management device 30 transmits the time correction information once a day, for example. The time correction information may be transmitted two or more times a day, or once a week. The frequency of transmitting the time correction information is not particularly limited.

[0061] Next, the determination unit 223 determines whether a predetermined time has elapsed after the time correction (S12). The predetermined time is, for example, five minutes, but may be ten minutes. The period from when the current time measured by the clock unit 25 is corrected until the predetermined time has elapsed is an example of the target period. In other words, the determination unit 223 determines whether it is the target period.

[0062] Here, the predetermined time is determined based on the configuration of the mesh network 40. The predetermined time is determined, for example, by a setting terminal that stores the configuration of the mesh network 40. Specifically, the configuration of the mesh network 40 refers to the number of transmissions (also referred to as the maximum number of hops) required for the time correction information transmitted by the time management device 30 to reach all of the communication devices 20 belonging to the mesh network 40. As described above, when information is transmitted using a routing method, a communication path that can distribute information to the communication devices 20 belonging to the mesh network 40 is set in advance. The predetermined time is determined by multiplying the number of transmissions obtained by referring to the communication path by the maximum time required for one transmission. Such a predetermined time is longer than the estimated error that may occur between the current times held by each of the multiple communication devices 20.

[0063] The specified time may be determined based on the period from when the time management device 30 starts distributing the time correction information until the distributed time correction information reaches all communication devices 20 belonging to the mesh network 40.

[0064] For example, the output unit 224 of a communication device 20 that has received the time correction information and corrected the current time may transmit a response signal to the time management device 30, and the time management device 30 may determine as the predetermined time half the time required from transmitting the time correction information to receiving the response signals from the output units 224 of all communication devices 20. Such a predetermined time is longer than the measured error that may occur between the current times held by each of the multiple communication devices 20.

[0065] If it is determined that a predetermined time has not elapsed after the time correction (No in S12), the communication device 20 transmits a control signal including information indicating the time before correction and information indicating the time after correction (S13). Specifically, the output unit 224 uses the communication unit 21 to transmit a control signal including time information indicating the time before correction and time information indicating the time after correction to another communication device 20 via the mesh network 40. The information indicating the time before correction is an example of first time information, and the information indicating the time after correction is an example of second time information.

[0066] The information indicating the time before correction is temporarily stored, at least during the target period, in the storage unit 23. The information indicating the time after correction may be the corrected time itself, or may be information indicating the difference between the time before correction and the time after correction.

[0067] If it is determined that a predetermined time has elapsed after the time correction (Yes in S12), the communication device 20 transmits a control signal including information indicating the corrected time (S14). Specifically, the output unit 224 uses the communication unit 21 to transmit the control signal including time information indicating the corrected time via the mesh network 40.

[0068] According to this operation, when the current time measured by clock unit 25 of communication device 20 is corrected, the control signal transmitted by communication device 20 during the target period includes information indicating the time before the correction and information indicating the time after the correction. Such communication device 20 can prevent a decrease in the communication security level even during the target period, i.e., the period during which the correction of the shared time is being performed.

[0069] Here, the above-mentioned determination is made by the communication device 20 that receives the control signal, and the communication device 20 that transmits the control signal is the communication device 20 that started transmitting the control signal. In a communication device 20 that does not start transmitting the control signal but only relays the transmission of the control signal, the above-mentioned determination is not made. By omitting the above-mentioned determination, such a communication device 20 can reduce the time required to transmit the control signal.

[0070] The above-described determination may also be performed in a communication device 20 that only relays the transmission of a control signal. By performing the above-described determination, such a communication device 20 can prevent communication congestion within the mesh network 40.

[0071] [Receiving Action] Next, a description will be given of the operation of communication device 20 when it receives a control signal. Fig. 4 is a flowchart illustrating the operation of communication device 20 according to the embodiment when it receives a signal.

[0072] First, the acquisition unit 221 acquires time correction information (S21). The control unit 222 corrects the current time measured by the timing unit 25 based on the time correction information acquired by the acquisition unit 221. The time correction information may be information indicating the corrected time, or may be information indicating the difference between the time before and the time after correction.

[0073] Next, the communication device 20 receives the control signal (S22). The acquisition unit 221 uses the communication unit 21 to receive the control signal that is sent by the other communication device 20 and transmitted via the mesh network 40.

[0074] When the control signal is received, the determination unit 223 determines whether or not a predetermined time has elapsed after correcting the time (S23). In other words, the determination unit 223 determines whether or not it is the target period.

[0075] If it is determined that the predetermined time has not elapsed after the time correction (No in S23), the determination unit 223 determines the time information included in the control signal based on the time before and after correction (S24). Note that the information indicating the time before correction is temporarily stored in the storage unit 23 for at least the target period.

[0076] If it is determined that a predetermined time has elapsed after the time has been corrected (Yes in S23), the determination unit 223 determines the time information included in the control signal based on the corrected time (S25).

[0077] Specifically, the determination unit 223 determines whether the time difference is within a predetermined range (S26). The predetermined range is, for example, 5 minutes, but may also be 10 minutes or a period of the same length as the predetermined time. The predetermined range may also be a period required for sharing time information in the mesh network 40.

[0078] If the control signal contains only one piece of time information, that is, if the control signal contains either first time information or second time information, the determination unit 223 determines whether the difference between the one or either of the two times held by the communication device 20 and the time indicated by the time information contained in the control signal is within a predetermined range. If the difference between either one of the one or two times is within the predetermined range, the determination unit 223 determines that the time difference is within the predetermined range.

[0079] When the control signal contains two pieces of time information, that is, when the control signal contains first time information and second time information, determination unit 223 determines whether the difference between one or either of the two times held by communication device 20 and the time indicated by the second time information is within a predetermined range, and if it is determined that the difference is not within the predetermined range, determination unit 223 further determines whether the difference between one or either of the two times held by communication device 20 and the time indicated by the first time information is within a predetermined range. When the difference between any one of the one to four times is within the predetermined range, determination unit 223 determines that the time difference is within the predetermined range.

[0080] If it is determined that the time difference is within the predetermined range (Yes in S26), the control unit 222 accepts the control signal (S27). Specifically, the control unit 222 executes control based on the acquired control signal.

[0081] If it is determined that the time difference is not within the predetermined range (No in S26), the control unit 222 discards the control signal (S28). Specifically, the control unit 222 does not execute control based on the acquired control signal.

[0082] According to this operation, when the current time measured by clock unit 25 of communication device 20 is corrected, communication device 20 judges the control signal received during the target period using the time before and after the correction. Such communication device 20 can prevent a decrease in the communication security level even during the target period, that is, the period during which the correction of the shared time is being performed.

[0083] Here, the above-mentioned determination is made by the communication device 20 that receives the control signal, and the communication device 20 that receives the control signal is the communication device 20 that is instructed to be controlled by the control signal. The above-mentioned determination is not made in a communication device 20 that is not instructed to be controlled by the control signal and that only relays the transmission of the control signal. By omitting the above-mentioned determination, such a communication device 20 can reduce the time required to transmit the control signal.

[0084] The above-described determination may also be performed in a communication device 20 that only relays the transmission of a control signal. By performing the above-described determination, such a communication device 20 can prevent communication congestion within the mesh network 40.

[0085] [Effects, etc.] The technologies derived from the disclosure of this specification are, for example, the following technologies. Below, the technologies derived from the disclosure of this specification will be described together with the effects and the like obtained by the technologies.

[0086] Technique 1 is a communication device 20 that is one of a plurality of communication devices 20 belonging to a mesh network 40, and includes a timing unit 25 that measures the current time, and an output unit 224 that outputs a control signal for controlling other communication devices 20 belonging to the mesh network 40, the control signal including time information indicating the current time measured by the timing unit 25, and the control signal including time information indicating the current time measured by the timing unit 25, during a target period from when the current time measured by the timing unit 25 is corrected to when a predetermined time has elapsed.

[0087] In such communication device 20, when the current time measured by timing unit 25 of communication device 20 is corrected, the control signal transmitted by communication device 20 during the target period includes information indicating the time before correction and information indicating the time before correction. Such communication device 20 can prevent a decrease in the communication security level even during the target period, that is, during the period when correction of the time shared among multiple communication devices 20 is being performed.

[0088] Technique 2 is a communication device 20 among a plurality of communication devices 20 belonging to a mesh network 40, the communication device 20 including: an acquisition unit 221 that acquires a control signal including time information from another communication device 20 among the plurality of communication devices 20; a timing unit 25 that measures the current time; a determination unit 223 that determines whether or not a difference between the current time measured by the timing unit 25 and the time indicated by the time information included in the control signal acquired by the acquisition unit 221 is within a predetermined range; and a control unit 222 that executes control based on the control signal, provided that it is determined that the difference between the current time measured by the timing unit 25 and the time indicated by the time information included in the control signal acquired by the acquisition unit 221 is within the predetermined range, and the determination unit 223 determines whether or not a difference between the current time before correction and the current time after correction and the time indicated by the time information included in the control signal is within a predetermined range during a target period from when the current time measured by the timing unit 25 is corrected and when a predetermined time has elapsed.

[0089] When the current time measured by the timing unit 25 of the communication device 20 is corrected, the communication device 20 judges the control signal received during the target period using the time before and after the correction. The communication device 20 can prevent a decrease in the communication security level even during the target period, that is, during the period when the time shared among multiple communication devices 20 is being corrected.

[0090] Technique 3 is communication device 20 of technique 2, in which acquisition unit 221 acquires a control signal including two pieces of time information during a target period, and determination unit 223 determines whether or not a difference between the current time before correction and the current time after correction and each of the two times indicated by the two pieces of time information included in the control signal during the target period is within a predetermined range.

[0091] When the current time measured by the clock unit 25 of the communication device 20 is corrected, the communication device 20 judges the control signal received during the target period using the time before and after the correction.

[0092] Technique 4 is communication device 20 of technique 2, in which, when acquisition unit 221 acquires a control signal including two pieces of time information, determination unit 223 determines whether the difference between the current time measured by timing unit 25 and each of the two times indicated by the two pieces of time information included in the control signal is within a predetermined range.

[0093] Such a communication device 20 can determine the control signal including two pieces of time information based on the current time measured by the clock unit 25 of the communication device 20.

[0094] Technique 5 is a communication device 20 according to any one of techniques 1 to 4, in which the predetermined time is determined based on the configuration of the mesh network 40.

[0095] Such a communication device 20 can estimate the error that may occur between the current times measured by the respective timing units 25 of the multiple communication devices 20 belonging to the mesh network 40, and determine the predetermined time.

[0096] Technique 6 is a communication device 20 according to any one of techniques 1 to 5, in which the correction of the current time measured by the timing unit 25 is performed based on time correction information distributed to multiple communication devices 20 by a time management device 30 included in the mesh network 40, and the specified time is determined based on the period from when distribution of the time correction information begins until the distributed time correction information reaches the multiple communication devices 20.

[0097] Such a communication device 20 can measure the error that may occur between the current times measured by the respective timing units 25 of multiple communication devices 20 belonging to the mesh network 40, and determine the predetermined time.

[0098] Technique 7 relates to the communication device 20 of any one of techniques 1 to 6, in which each of the plurality of communication devices 20 is a lighting-related device.

[0099] Such communication device 20 can prevent a decrease in the security level of communication even during a period in which correction of the time shared among a plurality of lighting-related devices is being performed.

[0100] Technique 8 is a communication system 10 that includes a plurality of communication devices 20, each of which operates as a communication device 20 of Technique 1 when transmitting information, and operates as a communication device 20 of any of Techniques 2 to 4 when receiving information.

[0101] Such a communication system 10 can prevent the security level of communication from decreasing even during the period when the time shared within the mesh network 40 is being corrected.

[0102] Technique 9 is an information processing method executed by one of a plurality of communication devices 20 belonging to a mesh network 40, the communication device 20 having a timing unit 25 that measures the current time, the information processing method including an output step of outputting a control signal for controlling other communication devices 20 belonging to the mesh network 40, the control signal including time information indicating the current time measured by the timing unit 25, in which the output step outputs a control signal including first time information indicating the current time before correction and second time information indicating the current time after correction during a target period from when the current time measured by the timing unit 25 is corrected until a predetermined time has elapsed.

[0103] Such an information processing method can prevent the security level of communication from decreasing even during the target period, that is, during the period when the time shared among multiple communication devices 20 is being corrected.

[0104] Technique 10 is a program for causing one communication device 20 to execute the information processing method of technique 9.

[0105] Such a program can help prevent a decrease in the security level of communication even during a period in which correction of the time shared among a plurality of communication devices 20 is being performed.

[0106] Technology 11 is an information processing method executed by one of a plurality of communication devices 20 belonging to a mesh network 40, the communication device 20 having a timing unit 25 that measures the current time, the information processing method including: an acquisition step of acquiring a control signal including time information from another communication device 20 of the plurality of communication devices 20; a determination step of determining whether or not a difference between the current time measured by the timing unit 25 and the time indicated by the time information included in the control signal acquired in the acquisition step is within a predetermined range; and a control step of executing control based on the control signal, on the condition that it has been determined that the difference between the current time measured by the timing unit 25 and the time indicated by the time information included in the control signal acquired in the acquisition step is within the predetermined range, in which the determination step determines whether or not a difference between the current time before correction and the current time after correction and the time indicated by the time information included in the control signal is within a predetermined range during a target period from when the current time measured by the timing unit 25 is corrected and when a predetermined time has elapsed.

[0107] Such an information processing method can prevent the security level of communication from decreasing even during the target period, that is, during the period when the time shared among multiple communication devices 20 is being corrected.

[0108] The twelfth aspect is a program for causing one communication device 20 to execute the information processing method of the eleventh aspect.

[0109] Such a program can help prevent a decrease in the security level of communication even during a period in which correction of the time shared among a plurality of communication devices 20 is being performed.

[0110] (Other embodiments) Although the embodiments have been described above, the present disclosure is not limited to the above-described embodiments.

[0111] For example, in the above embodiment, the communication system is realized by a plurality of devices. When the communication system is realized by a plurality of devices in this way, the components (particularly functional components) of the communication system may be allocated in any manner among the plurality of devices.

[0112] Furthermore, the method of communication between the devices in the above-described embodiments is not particularly limited. Furthermore, a relay device (such as a gateway device) (not shown) may be involved in the communication between the devices.

[0113] In the above-described embodiment, the processing performed by a specific processing unit may be performed by another processing unit. The order of multiple processing operations may be changed, or multiple processing operations may be performed in parallel.

[0114] In the above-described embodiments, each component may be realized by executing a software program suitable for that component, or by a program execution unit such as a CPU or processor reading and executing a software program recorded on a recording medium such as a hard disk or semiconductor memory.

[0115] Furthermore, each component may be realized by hardware. For example, each component may be a circuit (or integrated circuit). These circuits may form a single circuit as a whole, or each may be a separate circuit. Furthermore, each of these circuits may be a general-purpose circuit or a dedicated circuit.

[0116] Furthermore, the general or specific aspects of the present disclosure may be realized as a system, an apparatus, a method, an integrated circuit, a computer program, or a computer-readable recording medium such as a CD-ROM, or may be realized as any combination of a system, an apparatus, a method, an integrated circuit, a computer program, and a recording medium.

[0117] For example, the present disclosure may be realized as an information processing method executed by a computer such as the communication system of the above-described embodiments, or as a program for causing a computer to execute the information processing method (in other words, a computer program product).Furthermore, the present disclosure may be realized as a computer-readable non-transitory recording medium on which such a program is recorded.

[0118] In addition, this disclosure also includes forms obtained by applying various modifications to each embodiment that a person skilled in the art would think of, or forms realized by arbitrarily combining the components and functions of each embodiment within the scope that does not deviate from the intent of this disclosure. [Explanation of symbols]

[0119] 10. Communication Systems 20. Communication Equipment 221 Acquisition Department 222 Control Unit 223 Judgment section 224 Output Section 25 Timing section 30 Time management equipment 40 Mesh Network

Claims

1. One communication device among a plurality of communication devices belonging to a mesh network, a timing unit that measures the current time; an output unit that outputs a control signal for controlling other communication devices belonging to the mesh network, the control signal including time information indicating the current time measured by the clock unit; the output unit outputs the control signal including first time information indicating the current time before correction and second time information indicating the current time after correction during a target period from when the current time measured by the timing unit is corrected until a predetermined time has elapsed. Communication equipment.

2. One communication device among a plurality of communication devices belonging to a mesh network, an acquisition unit that acquires a control signal including time information from another communication device among the plurality of communication devices; a timing unit that measures the current time; a determination unit that determines whether a difference between the current time measured by the timing unit and the time indicated by the time information included in the control signal acquired by the acquisition unit is within a predetermined range; a control unit that executes control based on the control signal when it is determined that the difference between the current time measured by the timing unit and the time indicated by the time information included in the control signal acquired by the acquisition unit is within the predetermined range; the determination unit determines whether or not a difference between the current time before correction, the current time after correction, and the time indicated by the time information included in the control signal falls within the predetermined range during a target period from when the current time measured by the timing unit is corrected until a predetermined time has elapsed. Communication equipment.

3. When the acquisition unit acquires the control signal including two pieces of time information, the determination unit determines whether or not, during the target period, a difference between the current time before correction, the current time after correction, and each of the two times indicated by the two pieces of time information included in the control signal is within the predetermined range. The communication device according to claim 2 .

4. When the acquisition unit acquires the control signal including two pieces of time information, the determination unit determines whether or not a difference between the current time measured by the timekeeping unit and each of the two times indicated by the two pieces of time information included in the control signal is within the predetermined range. The communication device according to claim 2 .

5. The predetermined time is determined based on the configuration of the mesh network. The communication device according to any one of claims 1 to 4.

6. The current time measured by the timing unit is corrected based on time correction information distributed to the plurality of communication devices by a time management device included in the mesh network, the predetermined time is determined based on the period from when distribution of the time correction information begins until the distributed time correction information reaches the plurality of communication devices. The communication device according to any one of claims 1 to 4.

7. Each of the plurality of communication devices is a lighting-related device. The communication device according to any one of claims 1 to 4.

8. Equipped with multiple communication devices, Each of the plurality of communication devices operates as a communication device according to claim 1 when transmitting information, and operates as a communication device according to any one of claims 2 to 4 when receiving information. Communication system.

9. An information processing method executed by one communication device among a plurality of communication devices belonging to a mesh network, comprising: the communication device includes a clock unit that measures the current time; The information processing method includes: an output step of outputting a control signal for controlling other communication devices belonging to the mesh network, the control signal including time information indicating the current time measured by the clock unit; In the output step, the control signal including first time information indicating the current time before correction and second time information indicating the current time after correction is output during a target period from when the current time measured by the timing unit is corrected until a predetermined time has elapsed. Information processing methods.

10. A program for causing the one communication device to execute the information processing method according to claim 9.

11. An information processing method executed by one communication device among a plurality of communication devices belonging to a mesh network, comprising: the communication device includes a clock unit that measures the current time; The information processing method includes: an acquisition step of acquiring a control signal including time information from another communication device among the plurality of communication devices; a determination step of determining whether or not a difference between the current time measured by the timing unit and the time indicated by the time information included in the control signal acquired in the acquisition step is within a predetermined range; a control step of executing control based on the control signal on the condition that it is determined that the difference between the current time measured by the timing unit and the time indicated by the time information included in the control signal acquired in the acquisition step is within the predetermined range, In the determination step, during a target period from when the current time measured by the clock unit is corrected until a predetermined time has elapsed, it is determined whether or not a difference between the current time before correction, the current time after correction, and the time indicated by the time information included in the control signal is within the predetermined range. Information processing methods.

12. A program for causing the one communication device to execute the information processing method according to claim 11.

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