JP5643240B2 - Time setting method, communication device, and time setting program - Google Patents

Description

  The present invention relates to a communication device that communicates information including time information, and in particular, determines whether the own device becomes a master station or a slave station when exchanging time information between the own device and a communication partner. It relates to communication equipment.

  In recent years, the configuration of communication networks in which communication devices and communication terminals perform communication processing has become increasingly complex. In this communication network, the number of communication terminals is enormous, and is installed in a wide area of the communication network. The importance of time management for such communication terminals is increasing.

  That is, an increasing number of processes require highly accurate time information, such as the timing of execution of a scheduled process instructed via a communication network and the time to reference failure information as a history.

  As a time adjustment in a communication network, a method of accessing an NTP (Network Time Protocol) or SNTP (Simple Network Time Protocol) server and referring to the time is known.

  However, this method has a problem that, in a situation where the network is congested, access to the server is limited and time information necessary for processing cannot be acquired. Also, in order to avoid congestion of communication data, if it is attempted to simplify and reduce communication data, it becomes difficult to cope with security. That is, there is a risk that information such as the terminal information of the communication terminal that accesses the server may be fraudulent when referring to the time, and there is a risk that unauthorized access may occur in the accessing communication terminal. If many terminals try to share time information in a communication network, the risk of access to a server that is open to the public and to which time information is referenced increases. For this reason, it is required to manage time information while encrypting the communication path itself of the network including the server and distributing the load in the network.

  Therefore, safe, low-cost, and flexible time management is an important technology in the operation of modern communication networks. In such a network, a time management technique in which the own apparatus determines whether it is a master or a slave by itself according to the state inside the network is an important technique.

  Patent Document 1 discloses a method in which a master station equipped with a GPS (Global Positioning System) receiver performs time management of a plurality of slave stations that do not have a time information generation function.

  Patent Document 2 discloses a time information communication system in which a master station for time adjustment in a network simultaneously transmits time information to all slave stations, and time correction is performed on the slave side.

  Patent Document 3 discloses a communication device that calculates a network congestion index when accessing a time server in a network, and acquires time information using the congestion index as a criterion. When the time is congested, the reliability of time accuracy decreases due to packet loss or the like.

  Patent Document 4 discloses an alarm system that distributes time information by setting one of a plurality of alarm devices as a master station and the other as a slave station.

  Patent Document 5 discloses a mobile station that has two operation modes, a master mode that operates by specifying frame timing with a free-running clock, and a slave mode that operates in synchronization with a synchronization signal pattern. A wireless station that switches a clock master at a predetermined timing is disclosed.

  Patent Document 6 discloses a wireless device that compares a communication condition transmitted to a communication partner and a reply to the communication condition from the communication partner and switches the communication condition when they match.

  In Patent Document 7, when a signal requesting remote operation of an in-vehicle device is received, it is confirmed whether or not a precondition for performing the remote operation of the in-vehicle device is satisfied, and then the in-vehicle device is remotely driven. A remote control device is disclosed.

  Patent Document 8 is a time synchronization system that synchronizes a copy clock built in a processor node with a master clock built in an inter-node connection device, and controls communication data by determining the communication data receivable state of the processor node. A system is disclosed.

  Patent Document 9 discloses a time synchronization system that examines a routing route to a communication partner node, measures a delay time, and corrects a time offset between a master and a slave.

  Patent Document 10 relates to time stamp information from the master side device in the slave side device, and performs clock correction based on the time stamp information received this time, the time stamp information received until the previous time, and the transmission cycle information. A clock period system for performing is disclosed.

JP 2000-023245 A JP 2007-163330 A JP 2010-081381 A JP 2010-181921 A JP 2003-158766 A JP 2004-040212 A JP 2006-092130 A JP 2006-234711 A JP 2009-065579 A JP 2011-029918 A

  The communication environment has become increasingly complex in recent years, and there is a problem that a time management method suitable for such a communication environment is not provided.

  The time management method disclosed in Patent Document 1 is a method in which an expensive master station equipped with a GPS receiver performs time management of a plurality of slave stations such as a GPS receiver that do not have a time information generation function. Since the time update information is periodically transmitted from the master station, if a failure occurs in the master station, the time information of the normal slave station is updated with the time information of the incorrect master station, and the time information is lost in all slave stations. It will be broken. Further, for time correction due to propagation delay between the master station and the slave station, the master station individually calculates a correction value for each of the slave stations and transmits it to all the slave stations. For this reason, there is a large functional difference between the master station and the slave station, and when the number of slave stations increases in the network, the load is concentrated on the master station. In addition, the slave station has a problem that there is no means for determining the validity of the time information and propagation delay correction information transmitted from the master station. Also, the master / slave cannot be changed fluidly.

  In the time information communication system disclosed in Patent Document 2, a master station transmits time information to all slave stations simultaneously, and time correction is performed on the slave side. This reduces the burden on the master station for time adjustment in the network, but there is a problem that time information of all slave stations is lost when a failure occurs in the master station. Also, the case where access concentrates from the slave station to the master station for calculating the time correction information is not considered.

  The communication device disclosed in Patent Literature 3 calculates a network congestion index when accessing a time server in the network, and uses the congestion index as a determination criterion. The inquiry is canceled and the inquiry is made again after a certain time. However, if network congestion is not alleviated, time information with low reliability must be acquired after waiting for a certain period of time. For this reason, there exists a problem that the precision of time information may not improve.

  The alarm system disclosed in Patent Document 4 can arbitrarily set a master station / slave station for devices having the same function. However, one unit connected to an external clock function at the time of installation is a master station, and other devices in the network are fixed to the slave station and operate. For this reason, the master station / slave station is fixed at the time of installation. The installation range is also assumed to be close, and correction operations for time adjustment between the master station and the slave station are not considered. In addition, since it does not have a time generation function inside its own device, it cannot be used in facilities that do not have equipment with a clock function outside such as unmanned radio stations.

  In the wireless station disclosed in Patent Document 5, the master / slave can be fluidly changed in any set group, but the set group is not automatically changed. It is necessary to set a group from the outside by an operator or the like every time the change is made.

  In the wireless device disclosed in Patent Document 6, when the wireless condition is switched between the master and the slave, the master is set by the operator, and the slave is set following the master. For this reason, the operator does not need to make settings for a plurality of slave devices. However, the setting switching trigger is an operation of the operator with respect to the master, and the flow from detection of a defect to normalization cannot be automatically completed.

  The remote operation control device disclosed in Patent Document 7 determines whether or not a remote operation is possible when a vehicle-mounted wireless device is remotely operated. However, the remote operation trigger is an operator operation, and a series of processes from detection of a defect to normalization cannot be automatically completed.

  In the time synchronization system disclosed in Patent Document 8, the validity of data is determined based on a communication state such as frame synchronization, and the validity of time data is not determined. That is, there is a problem that even if the held time information is illegal, it is adopted without being discarded if the communication state is good.

  The time synchronization system disclosed in Patent Document 9 only calculates correction information, and cannot determine the validity of time information and correction information.

  The clock cycle system disclosed in Patent Document 10 stores the time stamp information received up to the previous time on the slave side, and calculates the correction value of the clock based on the comparison with the time stamp information received this time. For this reason, the master side and the slave side are fixed and cannot be changed fluidly.

  The present invention has been made in view of the above points. In a communication network constructed by inexpensive devices having the same function, when time adjustment is required, it becomes a master station or a slave depending on the state of its own device. By automatically determining whether to become a station and performing time adjustment, even if the number of devices installed in the network increases, a communication device that can perform time adjustment locally and perform stable time management is provided. The purpose is to do.

  In order to achieve the above object, a time setting method of the present invention is a time setting method for a communication device that sets time information by communication with another communication device, and is based on the time information set in the communication device. A step of selecting one of a master station mode for setting time information of another communication device and a slave station mode for setting time information of the communication device based on the time information set for the other communication device. It is characterized by having.

  The communication device of the present invention is a communication device that sets time information by communication with another communication device, and includes a time management unit that manages time information of the own device, and time information set in the communication device. Control that operates in either a master station mode that sets time information of another communication device based on a slave station mode that sets time information of a communication device based on time information set in another communication device And a conditional expression holding unit that holds a conditional expression for selecting one of the master station mode and the slave station mode.

  Furthermore, the time setting program of the present invention is a time setting program for a communication device that sets time information by communication with another communication device, and is based on the time information set for the communication device. Causes a computer to perform mode selection processing for selecting either a master station mode for setting information and a slave station mode for setting time information of a communication device based on time information set for another communication device It is characterized by that.

  According to the present invention, in a communication network constructed by a plurality of communication devices, when time adjustment is necessary, it is automatically determined whether to become a master station or a slave station depending on the state of the own device. Since the time adjustment is performed locally, the communication load is distributed and no human operation is required.

1 shows an exemplary configuration of a communication apparatus according to an embodiment of the present invention. 2 shows an example of a configuration of transmission data / reception data transmitted / received between communication devices in a network according to an embodiment of the present invention. 6 is a flowchart illustrating an example of processing until time adjustment is started as a slave station side communication device in the communication device according to the embodiment of the present invention. An example of a structure of the communication apparatus which opposes embodiment of this invention is shown. 6 is a flowchart showing an example of time adjustment processing in the slave station side communication apparatus according to the embodiment of the present invention. 6 is a flowchart illustrating an example of processing until time adjustment is started as a master station side communication device in the communication device according to the embodiment of the present invention. 7 is a flowchart illustrating an example of processing in which a master station side communication device calculates a correction information value for time adjustment in the communication device according to the embodiment of the present invention.

Embodiments of the present invention will be described with reference to the drawings. However, the present invention is not limited to the embodiments shown below.
[First embodiment]
Next, embodiments of the present invention will be described in detail with reference to the drawings. However, the present invention is not limited to the embodiments shown below.

  FIG. 1 shows an example of the configuration of a communication apparatus according to an embodiment of the present invention.

  The communication device 100 according to the embodiment of the present invention includes an interface unit 3 that receives an external input of a main signal 10 from a terminal device 200, a signal processing unit 4 that performs digital signal processing such as multiplexing on the main signal 10, and a digital signal to an opposite device. A modem unit 5 that transmits the signal-processed signal as transmission data 8 is included. The communication apparatus 100 further includes a time management unit 1, a signal processing unit 4, and a control unit 2 that controls the time management unit 1. The control unit 2 is connected to a conditional expression holding unit 7 that holds a conditional expression serving as a determination criterion at the present time. The conditional expression holding unit 7 includes a condition update unit 6 that rewrites the held conditional expression. Connected.

  The modem unit 5 also receives the received data 9 from the opposite device, the received data 9 is subjected to digital signal processing such as separation by the signal processing unit 4, and the processed data is output to the terminal device 200 by the interface unit 3. .

  FIG. 2 shows an example of a configuration of transmission data 8 / reception data 9 transmitted / received between apparatuses according to the embodiment of the present invention.

  Data transmitted and received between opposing devices is multiplexed with a main signal 10 and an overhead (OH) signal 11 composed of a plurality of additional information necessary for communication.

  In the communication apparatus 100 shown in FIG. 1, the control unit 2 initializes the time management unit 1 to start timekeeping, and periodically reads time information from the time management unit 1.

  The control unit 2 makes an inquiry to the conditional expression holding unit 7 regarding the condition for determining whether to become a master station or a slave station when time adjustment is performed between the opposing devices, and determines its own device according to the result of the inquiry to the determination condition. After determining that is a master station or a slave station, time adjustment processing between the opposing devices is started.

  Next, a communication operation according to the embodiment of the present invention will be described in detail with reference to the drawings.

  In this embodiment, the communication operation will be described using the communication apparatus 100 that requires time management as shown in FIG.

  The communication device 100 according to the present embodiment receives an external input of a main signal from the terminal device in the interface unit 3. The main signal is subjected to digital signal processing such as multiplexing in the signal processing unit 4, and the processed signal is transmitted as transmission data to the opposite device in the modem unit 5.

  Alternatively, the received data received by the modem unit 5 from the opposite device is subjected to digital signal processing such as separation by the signal processing unit 4, and the processed signal is output to the external terminal by the interface unit 3.

  As shown in FIG. 2, in the transmission data / reception data, a main signal 10 and an OH signal 11 composed of a plurality of additional information necessary for communication are multiplexed.

  When the control unit 2 makes initial settings such as region information and the current time in the time management unit 1, the time management unit 1 starts measuring time.

  The control unit 2 periodically reads the time information of the time management unit 1 according to an arbitrarily set cycle, compares the time read this time with the time read last time, and sets the read cycle set Monitor whether the minute time is ahead.

  Further, the control unit 2 determines whether to become a master station or a slave station when performing time adjustment between the opposing devices. That is, the control unit 2 has a function of referring to the conditional expression holding unit 7 for a determination condition, and becomes a master station based on a result of comparing the state of the own apparatus and the condition set in the conditional expression holding unit 7. Or a slave station is determined, and time synchronization between the opposing devices is started.

The conditional expression holding unit 7 stores determination conditions in the form of logical expressions. The following are examples of determination conditions.
1. Timekeeping operation Becomes a master station when it is normal with regular updates /
If it is illegal without regular update, it becomes a slave station. About time information When it is within the range of 00:00:00 to 24:00 and is normal, it becomes a master station /
2. When it is not within the range of 00:00:00 to 24:00 and is illegal, it becomes a slave station. Time information transmission request reception No transmission request received /
When there is a transmission request reception, it becomes a master station. The above determination condition will be described with reference to FIG.

  The control unit 2 reads and holds the time information of the time management unit 1 periodically (step S301) according to a predetermined cycle (step S302). When reading is performed for the second time (step S303), the time read this time is compared with the time read last time (step S304), and it is confirmed whether or not the time is set by the set read cycle (step S304). Step S305).

  Immediately after the communication device is activated, the time management unit 1 holds the time information initial value at the time of activation until the control unit 2 performs the initial setting. For this reason, time measurement is not performed and the value of the time information periodically read from the control unit 2 becomes the same over a plurality of times.

  If the read value is advanced by the read cycle, the control unit 2 assumes that the timing operation is normal (step S306). If they are the same, it is detected that the timekeeping operation is invalid, and the state of the own device is inquired of the conditional expression holding unit 7.

  If the above-described condition example is set in the conditional expression holding unit 7 that has received the inquiry, the condition example 1 matches. At this time, it is determined that “the time adjustment operation is invalid and the time synchronization between the opposite parties starts as a slave station”, and a transmission request for time information is transmitted to the opposite station (step S307).

  Next, an example of a time adjustment procedure in the opposing communication apparatus will be described with reference to FIGS. 4 and 5.

  4, the master station side communication device 300 and the slave station side communication device 400 have the same configuration as the communication device 100 in FIG. Here, data transmitted from the slave station side communication device 400 to the master station side communication device 300 is referred to as transmission data 48, and data transmitted in the reverse direction is referred to as transmission data 38.

  FIG. 5 is a flowchart showing an example of time adjustment processing in the slave station side communication device.

  In the slave station side communication device 400, the time information transmission request signal is multiplexed with the OH signal 11 in the signal processing unit 44 and transmitted from the modem unit 45 to the opposing master station side communication device 300 as transmission data 48 (step S501). ). The master station side communication device 300 receives the time information transmission request signal and returns the transmission data 38 to the slave station side communication device 400. The slave station side communication device 400 receives the transmission data 38 (step S502), and time information, correction information, and correction information status multiplexed in the OH signal 11 are separated from the received data by the signal processing unit 44 ( Step S503).

  When the correction information status value indicates valid (step S504 YES), the control unit 42 sets the time information corrected with the correction value in the time management unit 41 as the correct time of the slave station side communication device 400 (step S505). ).

  Next, the time adjustment procedure for the master station side communication apparatus 300 will be described with reference to FIG.

  In the master station side communication apparatus 300, when the time information transmission request is received from the opposite slave station side communication apparatus 400 (step S601), the control unit 32 inquires of the conditional expression holding unit 37 about the state of the own apparatus. When the conditions for becoming a master station are satisfied in all of the above condition examples 1 to 3, that is, when the timing operation is normal (YES in step S602) and the time information is within a predetermined range (YES in step S603), It is determined that the time information transmission request is received from the opposite station and the time information is reliable, so that the master station starts time adjustment between the opposite devices (step S604). When at least one of the above conditions is not satisfied, it operates as a slave station (step S605), and time adjustment is performed as necessary. The signal processing unit 34 multiplexes time information, correction information, and correction information status on the OH signal 11, and the modem unit 35 transmits this signal to the slave station side communication device 400 as transmission data 38.

  When both opposing communication apparatuses become slave stations, the time information transmission request is transmitted again to a communication apparatus different from these communication apparatuses.

  The correction information is calculated by the master station side. The procedure for calculating the correction information will be described with reference to FIGS.

  Prior to the calculation, the master station side communication device 300 puts a value indicating “invalid” in the correction information status and transmits time information to the slave station side communication device 400 (step S701).

  In the slave station side communication device 400, since the value of the correction information status is “invalid” (step 504 NO in FIG. 5), the time management unit 41 does not perform time setting processing. The slave station side communication device 400 transmits the received time information value and the time information transmission request signal to the master station side communication device 300 (step S506 in FIG. 5).

  The master station side communication device 300 receives the data 48 returned from the slave station side communication device 400 (step S702). In the master station side communication device 300, since the value of the correction information status of the time information returned from the slave station side communication device 400 is “invalid”, the returned time information and the current time information of the own device are used. Compare.

  As a result of the comparison, the time difference is the transmission propagation delay time from the master station side communication apparatus 300 to the slave station side communication apparatus 400, and the reception propagation delay time that the master station side communication apparatus 300 receives a reply from the slave station side communication apparatus 400 And the sum. Since the transmission path and the reception path are generally considered to be the same path, a value that is ½ times the time difference between the reply time information from the slave station side communication apparatus 400 and the current time information of the own apparatus is set as the transmission path. Only the correction information value is set (step S703).

  After the master station side communication device 300 calculates the correction value according to the above procedure, the correction information status value is set to “valid”, and the slave station side communication device 400 again transmits the current time information of the own device and the calculated correction value. Information and correction information status are transmitted (step S704).

  In the slave station side communication device 400, since the value of the received correction information status is “valid”, the control unit 42 corrects the time information with the correction information and sets the time information in the time management unit 41 of the own device. .

  With the above procedure, time adjustment between the facing communication devices is completed.

  The condition for determining whether to become a master station or a slave station may be changed from the opposite station. For example, as illustrated in FIG. 1, the communication apparatus 100 may include a conditional expression update unit 6 connected to the conditional expression holding unit 7. The logical data of the judgment condition and the logical data update control signal of the condition are multiplexed with the OH signal 11 and transmitted from the opposite station, and the logical data of the judgment condition and the logical expression of the condition are received from the received data in the signal processing unit 4. The data update control signal is separated and transferred to the condition update unit 6. That is, the data held in the conditional expression holding unit 7 is rewritten by remote operation via the condition update unit 6.

As described above, by defining the optimum conditional expression for the system, the time adjustment processing in the network constituted by a plurality of opposing communication devices is locally performed. As a result, the communication load is distributed. In addition, the number of man-hours for human operations is reduced, and time management is performed appropriately [second embodiment].
The basic configuration of the communication apparatus according to the embodiment of the present invention is as described in the first embodiment, but the present invention is not limited to the first embodiment.

The communication device according to the second embodiment can change the determination condition for whether the device is a master station or a slave station.
By changing the determination condition, the time adjustment condition is set in more detail.

  In the communication apparatus according to the second embodiment, the master station side communication apparatus performs time adjustment by weighting the accuracy of time information based on the time adjustment execution history or time adjustment means. That is, priority is given to the time information.

  For example, when the history of time adjustment is new, it is considered that the time deviation is small and the accuracy is high, and the priority is increased and used for time adjustment. In addition, the time adjustment means is processed with higher priority in the process by the user's operation than in the automatic process.

  Furthermore, a station having highly accurate time information may be selected in advance as a master station in a network constituted by a plurality of opposing communication devices. Thereby, more accurate time adjustment can be realized.

  In a communication network constructed by a plurality of communication devices, the communication device according to the embodiment of the present invention automatically determines whether to become a master station or a slave station depending on the state of the own device when time adjustment is required. Judgment is made and time adjustment is performed locally. Thereby, communication addition is distributed, no human operation is required, and appropriate time management is provided.

  In addition, the communication device according to the embodiment of the present invention can arbitrarily set a determination condition as to whether to become a master station or a slave station when performing time adjustment. This setting change can be performed by remote control. For this reason, optimization for each system is easy.

  As mentioned above, although this invention was demonstrated with reference to embodiment, this invention is not limited to said each embodiment. Various changes that can be understood by those skilled in the art can be made to the configuration and details of the present invention. Further, the present invention includes a combination of some or all of the configurations of the above-described embodiments as appropriate.

  For example, since operation does not necessarily require human operation, it can be applied to a communication device used in an unmanned station.

  The present invention is not limited to the above embodiment, and can be suitably applied to a communication network including a plurality of communication devices having different roles such as a master station and a slave station.

1, 31, 41 Time management unit 2, 32, 42 Control unit 3, 33, 43 Interface unit 4, 34, 44 Signal processing unit 5, 35, 45 Modem unit 6, 36, 46 Conditional expression update unit 7, 37, 47 Conditional expression holding unit 8, 38, 48 Transmission data 9 Reception data 10 Main signal 11 OH signal 100 Communication device 200 Terminal device 300 Master station side communication device 400 Slave station side communication device

Claims (2)

A time setting method between opposing communication devices ,
The mode of each of the communication device, and the master station mode for setting the time information of the communication apparatus of the counterpart on the basis of its own time information, self-time information based on the time information set in the communication apparatus of the counterpart a mode setting step for setting to one of the modes of the slave station mode to set,
Possess a master communication device wherein a said communication device which is set to the master station mode, and time setting step of performing a time synchronization between the slave communication apparatus to be the communication device set in the slave station mode,
The time setting step includes
First data including first time information that is time information at the time of transmission and correction information status in which a first status that is a status indicating invalidity of time alignment in the slave communication device is set from the master communication device. A first step of transmitting to the slave communication device;
A second step of returning the received first time information from the slave communication device to the master communication device when the correction information status of the received first data is the first status;
The master communication device calculates a value of ½ of the difference between the second time information, which is the time information when the returned first time information is received, and the returned first time information. A third step with the correction information as
Second data including third time information that is time information at a predetermined time point, the correction information, and the correction status in which a second status that is a status that enables time adjustment in the slave communication device is set, A fourth step of transmitting from the master communication device to the slave communication device;
When the correction information status of the received second data is the second status, in the slave communication device, time information obtained by correcting the third time information with the correction information is used as time information of the slave communication device. 5th step to set
Time setting method characterized by having a. And further comprising the step of changing the conditions for selecting one of the modes of the master station mode and the slave station mode, the time setting method according to claim 1.

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