JP2007101457A - Transmitter, receiver, time notification method, and time setting method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To tick the same time between a plurality of devices by wirelessly transmitting information of time ticked by one device, even in an unstable wireless environment. <P>SOLUTION: A transmission terminal 100 generates a time notification packet, including notification time data indicating a notification time, measures a transmission delay time that is delay regarding transmission of the time notification packet, including the transmission delay time data indicating the transmission delay time in the time notification packet, and wirelessly transmits the time notification packet including the notification time data and the transmission delay time data to a plurality of receivers 200 by broadcasting. The receivers 200 measures the receiving delay time being delay regarding receiving of the time notification packet, sets the time on the basis of the notification time data, the transmission delay time data and receives delay time data included in the time notification packet, and synchronizes between the transmitter 100 and the receiver 200. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a time synchronization technique in which when there are two or more terminals, information on the time recorded in one terminal is transferred to another terminal so that the same time is recorded among a plurality of terminals.

Generally, in time synchronization aiming at transferring the time of one terminal to another terminal and keeping the same time, a time error due to a transfer delay is a problem. In order to synchronize the time with high accuracy, a method for measuring and correcting this time error is required. At this time, on the receiving side, the measured delay time may be set at the time setting time, but how to transmit the transmission delay becomes a problem. For example, Patent Document 1 measures a delay time when time information is transmitted, and transmits this delay time in the second communication.
JP-A-9-83608

  When the above-described conventional time synchronization method is applied to radio, the radio communication has a problem that the communication success rate changes significantly according to the environment. For example, when the time information of one terminal is simultaneously transmitted to a plurality of terminals using broadcast, when there are two packets, the first packet can be received but the next cannot be received, or vice versa. appear. Therefore, when time information and delay information are transmitted in different packets as in Patent Document 1, there is a problem that data consistency cannot be obtained.

  One object of the present invention is to solve the above-described problems, and a main object is to reliably transmit time and delay information to a plurality of terminals by broadcast using, for example, wireless communication.

The transmission device according to the present invention is:
A transmitting device for notifying a predetermined receiving device of a time,
A packet generation unit that generates a packet including notification time data indicating a notification time as a time notification packet;
A transmission delay time measurement unit that measures a transmission delay time that is a delay time in the transmission device;
A data synthesis unit that includes transmission delay time data indicating the transmission delay time measured by the transmission delay time measurement unit in a time notification packet;
A packet transmission unit configured to transmit a time notification packet including notification time data and transmission delay time data to the receiving device;

  According to the present invention, both the notification time data and the transmission delay time data can be included in one time notification packet and transmitted to the receiving apparatus, so that the notification time data and the transmission delay time data are different from each other. There is no need to send in packets. As a result, the notification time data reaches the receiving device, but the transmission delay time data does not reach the receiving device due to packet loss, or conversely, the transmission delay time data reaches the receiving device, but is notified due to packet loss. It is possible to avoid a situation in which the time data does not reach the receiving apparatus, thereby suppressing a time error component and realizing highly accurate time exchange.

Embodiment 1 FIG.
FIG. 1 is a diagram illustrating a configuration example of a wireless communication system targeted by the present embodiment.

  In FIG. 1, the transmission device 100 notifies time to the plurality of reception devices 200 by broadcast communication. The transmission apparatus 100 includes notification time data indicating time in the transmission apparatus 100 and transmission delay time data indicating transmission delay time, which is a delay time in the transmission apparatus 100, in one packet, and transmits this packet to each reception apparatus 200. To do. A packet transmitted by the transmitting apparatus 100 is called a time notification packet. Hereinafter, the time notification packet is also referred to as “packet”, “wireless packet”, “transmission packet”, and “reception packet”.

  When receiving the time notification packet, the receiving device 200 measures a reception delay time that is a delay time in the receiving device 200, and includes notification time data, transmission delay time data, and measured reception delay included in the time notification packet. Time is set using reception delay time data indicating time.

  In the present embodiment, a wireless communication system is taken as an example, but a wired communication system may be used.

  FIG. 2 is a diagram illustrating a configuration example of the transmission device 100 according to the present embodiment.

  In FIG. 2, a CPU (Central Processing Unit) 101 performs wireless packet generation processing. The CPU 101 is an example of a packet generation unit.

  The wireless chip 102 transmits the packet generated by the CPU 101 as a wireless signal. The wireless chip 102 is an example of a packet transmission unit.

  The clock 103 keeps time and generates an alarm when it is time to notify the receiving device 200 of time. The clock 103 is an example of an alarm generation unit.

  The timer 104 measures a transmission delay time that is a delay time when transmitting the time notification packet.

  The wireless monitoring / control unit 105 monitors alarms generated by the clock 103 and data between the CPU 101 and the wireless chip 102, controls termination of the timer 104, and manages transmission delay time measurement. Then, transmission delay time data indicating the transmission delay time is generated and output to the combining unit 106. Note that the timer 104 and the wireless monitoring / control unit 105 are examples of a transmission delay time measurement unit. Also, the inside of the wireless monitoring / control unit 105 has a configuration shown in FIG. 4, for example. The details of the internal configuration of the wireless monitoring / control unit 105 will be described later.

  The combining unit 106 merges the wireless packet generated by the CPU 101 with the transmission delay time data transmitted from the wireless monitoring / control unit 105. The combining unit 106 is an example of a data combining unit.

  In addition, as a signal line between the blocks, an alarm line 111 notifies the CPU 101 and the timer 104 that the clock 103 has reached the time set by the CPU 101.

  The time data line 112 is used when the CPU 101 reads time from the clock 103.

  The wireless transmission data line 113 is used when the CPU 101 transfers a wireless packet to the wireless chip 102, and further, the wireless monitoring / control unit 105 monitors whether or not a wireless packet is transmitted between the CPU 101 and the wireless chip 102. Used for.

  The stop signal line 114 is used when the wireless monitoring / control unit 105 instructs the timer 104 to stop measuring the transmission delay time.

  The measurement data line 115 is used when notifying the wireless monitoring / control unit 105 of the measurement value of the timer 104.

  The transmission delay time output line 116 is used when the wireless monitoring / control unit 105 outputs transmission delay time data to the combining unit 106.

  FIG. 3 is a diagram illustrating a configuration example of the reception device 200 according to the present embodiment.

  In FIG. 3, the CPU 201 inputs a received packet from the wireless chip 202 and extracts notification time data and transmission delay time data from the received packet. Further, the extracted notification time data and transmission delay time data are output to the clock 203. The CPU 201 is an example of a data extraction unit.

  The wireless chip 202 receives the time notification packet from the transmission device 100 as a reception packet and transfers it to the CPU 201. The wireless chip 202 is an example of a packet receiving unit.

  The clock 203 inputs the notification time data and the transmission delay time data extracted by the CPU 201 and stops measuring the reception delay time for the timer 204 when the notification time data and the transmission delay time data are input. Instruct. The clock 203 sets the time using the input notification time data, transmission delay time data, and reception delay time data indicating the reception delay time. The clock 203 is an example of a time setting unit.

  The timer 204 measures a reception delay time that is a delay time when the time notification packet is received. Then, reception delay time data indicating the reception delay time is output to the clock 203.

  The wireless monitoring / control unit 205 monitors data between the CPU 201 and the wireless chip 202, controls the start of the timer 204, and manages the measurement of the reception delay time. The timer 204 and the wireless monitoring / control unit 205 are examples of a reception delay time measurement unit. Also, the inside of the wireless monitoring / control unit 205 has a configuration shown in FIG. 4, for example. The details of the internal configuration of the wireless monitoring / control unit 205 will be described later.

  Further, as a signal line between the blocks, a wireless reception data line 217 is used when the wireless chip 202 transfers a wireless packet to the CPU 201, and further, a wireless monitoring / control unit 205 connects the CPU 201 and the wireless chip 202. This is used to monitor whether or not a wireless packet is transmitted.

  The time data line 212 outputs the time notification data and the transmission delay time data extracted by the CPU 201 to the clock 203.

  The start signal line 214 is used when the wireless monitoring / control unit 205 instructs the timer 204 to start reception delay time measurement.

  The measurement data line 215 is used when notifying the clock 203 of the measurement value of the timer 204.

  The stop signal line 218 is used when the clock 203 instructs the timer 204 to stop measuring the reception delay time.

  Next, operations of the transmission device 100 and the reception device 200 will be outlined with reference to FIGS.

  FIG. 6 is a flowchart for explaining an operation example of the transmission apparatus 100, and FIG. 7 is a flowchart for explaining an operation example of the reception apparatus 200.

  First, an exemplary operation of the transmission apparatus 100 will be outlined with reference to FIG.

  First, in step S601, the clock 103 generates an alarm when it is time to notify the receiving apparatus 200 (notification time) (alarm generation step). This alarm is notified to the CPU 101 and the timer 104. Further, the clock 103 outputs notification time data indicating an alarm occurrence time (= notification time) to the CPU 101. Note that the notification time is set in advance by the CPU 101.

  Next, in step S602, the timer 104 detects the occurrence of an alarm and starts measuring the transmission delay time (transmission delay time measurement step).

  Next, in step S603, the CPU 101 generates a time notification packet including notification time data indicating the alarm occurrence time (packet generation step).

  Next, in step S <b> 604, the CPU 101 outputs a time notification packet to the wireless chip 102.

  Next, in step S605, the wireless monitoring / control unit 105 detects the output of the time notification packet from the CPU 101 to the wireless chip 102 (transmission delay time measuring step). The wireless monitoring / control unit 105 monitors input / output of data between the CPU 101 and the wireless chip 102 and detects when a time notification packet is output from the CPU 101 to the wireless chip 102. Then, the wireless monitoring / control unit 105 instructs the timer 104 to stop measuring the transmission delay time.

  Next, in step S606, the timer 104 stops measuring the transmission delay time (transmission delay time measuring step). Then, the time from the occurrence of the alarm until the detection of the output of the time notification packet to the wireless chip 102 from the CPU 101 is defined as a transmission delay time, and the measured value is output to the wireless monitoring / control unit 105. Outputs transmission delay time data indicating the transmission delay time to the combining unit 106.

  Next, in step S607, the synthesis unit 106 includes transmission delay time data in the time notification packet. The combining unit 106 acquires the time notification packet output from the CPU 101 to the wireless chip 102, and includes the transmission delay time data from the wireless monitoring / control unit 105 in the time notification packet.

  Finally, in step S608, the wireless chip 102 transmits a time notification packet including the notification time data and the transmission delay time data to the receiving device 200.

  Next, an operation example of the receiving apparatus 200 will be outlined with reference to FIG.

  First, in step S701, the wireless chip 202 receives a time notification packet including notification time data and transmission delay time data (packet reception step).

  In step S <b> 702, the wireless chip 202 outputs a time notification packet to the CPU 201.

  Next, in step S703, the wireless monitoring / control unit 205 detects the output of a time notification packet from the wireless chip 202 to the CPU 201 (reception delay time measuring step). The wireless monitoring / control unit 205 monitors data input / output between the CPU 201 and the wireless chip 202, and detects when a time notification packet is output from the wireless chip 202 to the CPU 201. Then, the wireless monitoring / control unit 205 instructs the timer 204 to start measuring the transmission delay time.

  Next, in step S704, the timer 204 starts measuring the reception delay time based on the measurement start instruction from the wireless monitoring / control unit 205 (reception delay time measurement step).

  Next, in step S705, the CPU 201 extracts time notification data and transmission delay time data included in the time notification packet (data extraction step).

  Next, in step S <b> 706, the CPU 201 outputs the extracted time notification data and transmission delay time data to the clock 203.

  In step S707, the clock 203 inputs time notification data and transmission delay time data, and instructs the timer 204 to stop measuring the reception delay time. As a result, the timer 204 receives a clock from the CPU 201. Output of time notification data and transmission delay time data to 203 is detected (reception delay time measurement step).

  Next, in step S708, the timer 204 stops measuring the reception delay time (reception delay time measurement step). The time from the detection of the time notification packet output from the wireless chip 202 to the CPU 201 to the detection of the output of the time notification data and transmission delay time data from the CPU 201 to the clock 203 is defined as the reception delay time, and the measurement value is the reception delay time data. To the clock 203.

  Finally, in step S709, the clock 203 sets the time based on the time notification data and transmission delay time data input from the CPU 201 and the reception delay time data input from the timer 204. Specifically, a value obtained by adding the delay time indicated by the transmission delay time data and the delay time indicated by the reception delay time data to the time indicated by the time notification data is set as the current time.

  Next, a detailed configuration example of the wireless monitoring / control unit 105 of the transmission device 100 and the wireless monitoring / control unit 205 of the reception device 200 is shown in FIG.

  In FIG. 4, a synchronization unit 51 synchronizes transmission packets or reception packets and separates them into preamble data and synchronization signal data.

  The frame control unit 52 controls the output timing of the measurement value data (transmission delay time data or reception delay time data) based on the bit count signal from the synchronization unit 51.

  The comparator 53 compares the preamble data sorted by the synchronization unit 51.

  The comparator 54 compares the synchronization signal data.

The AND gate 55 becomes significant when the preamble and the synchronization pattern match.
The AND gate 56 is an output gate for measured value data from the timer.

  Next, the operation of time synchronization according to the present embodiment will be described in detail.

  First, the CPU 101 sets the notification time in the clock 103 via the time data line 112 in advance.

  The clock 103 notifies the CPU 101 of an alarm when the set notification time is reached. At this time, the timer 104 receives this alarm and starts measuring the transmission delay time.

  The CPU 101 receives the alarm, reads the notification time data from the clock 103 via the time data line 112, and generates a time notification packet including the notification time data. At this time, a data field for storing transmission delay time data is left in the packet, and an arbitrary value such as 0 is put therein. As shown in FIG. 5, a general wireless packet includes a preamble 501 indicating communication preparation, a synchronization signal 502 indicating the beginning of meaningful data, a destination, a data field 503 storing notification time data, and a data It consists of an end signal 504 indicating the end. The data field 503 is divided into valid data 505 such as destination / time generated by the CPU 101 and an invalid area 506. The valid data 505 such as destination / time includes notification time data. The CPU 101 stores the generated time notification packet in a memory or the like, and requests the wireless chip 102 to start transmission. Upon receiving the request, the wireless chip 102 reads the time notification packet from the memory of the CPU 101 via the wireless transmission data line 113 and wirelessly transmits it.

  The wireless monitoring / control unit 105 monitors the wireless transmission data line 113 and detects the preamble 501 and the synchronization signal 502 by the synchronization unit 51 and the comparators 53 and 54. When the synchronization signal 502 is detected, the AND gate 55 becomes significant and a signal is transmitted to the stop signal line 114 to notify the timer 104 of the end of measurement. The frame control unit 52 of the wireless monitoring / control unit 105 detects the start timing of the invalid area 506 based on the frame count signal output from the synchronization unit 51.

  At the timing when the signal on the wireless transmission data line 113 enters the invalid area 506, the output gate 56 of the wireless monitoring / control unit 105 becomes significant, and the measurement value of the timer 104 is output as transmission delay time data. Merge into the field. As a merging method, addition or logical sum is performed if the value of the data field set by the CPU 101 is 0, and replacement is performed if the value is another value. As described above, the invalid area 506 of the transmission wireless packet is replaced with the transmission delay time data 507, and is transmitted wirelessly from the wireless chip 102.

  Note that the alarm of the clock 103 may be used for purposes other than the transmission of time information. In this case, the timer 104 starts measuring the transmission delay time by an alarm, but the time notification packet including the notification time data to be expected is not output from the CPU 101 to the wireless chip 102, and the measurement cannot be completed indefinitely. Will occur. In order to prevent this, the measurement time is limited. That is, if a stop signal is not notified to the timer 104 even after a time longer than the maximum value of the transmission delay time, the measurement is forcibly terminated. In addition, when a time notification packet is output from the CPU 101 to the wireless chip 102 after the measurement is forcibly terminated, an error code may be inserted into a data field in which transmission delay time data is to be entered.

  Next, the receiving side will be described.

  When receiving the time notification packet, the wireless chip 202 transmits the time notification packet to the CPU 201 via the wireless reception data line 217. The radio monitoring / control unit 205 monitors the radio reception data line 217 and detects the preamble 501 and the synchronization signal 502 by the synchronization unit 51 and the comparators 53 and 54. When the synchronization signal 502 is detected, the AND gate 55 becomes significant and sends a signal to the start signal line 214 to notify the timer 204 of the start of measurement of the reception delay time. The timer 204 receives this notification and starts measuring the reception delay time.

  Upon receiving the time notification packet, the CPU 201 analyzes the received wireless packet, and when detecting reception of the time notification packet, extracts the notification time data and the transmission delay time data in the packet, Transmission delay time data is transmitted to the clock 203 via the time data line 212.

  The clock 203 that has received the notification time data and the transmission delay time data from the CPU 201 issues a signal to the stop signal line 218 to notify the timer 204 of the stop of the reception delay time measurement. Receiving the measurement stop notification, the timer 204 stops the reception delay time measurement and outputs the reception delay time data to the measurement data line 215. The clock 203 sets a value obtained by adding the transmission delay time data similarly received from the CPU 101 and the reception delay time data read from the measurement data line 215 to the notification time data received from the CPU 101 as the current time value.

  The wireless monitoring / control unit 205 notifies the timer 204 of the start of measurement every time a packet is received, but the received packet may not be a time notification packet. In this case, although the timer 204 starts to measure the reception delay time, a stop notification is not transmitted from the clock 203, and a state in which the measurement of the reception delay time cannot be completed indefinitely occurs. In order to prevent this, the measurement time is limited. That is, if a stop signal is not notified to the timer 204 even after a time longer than the maximum value of the reception delay time, the measurement is forcibly terminated. When the notification time data and transmission delay time data are output from the CPU 201 to the clock 203 after the measurement is forcibly terminated, an error code is inserted into the data field in which the reception delay time data is to be inserted. Also good.

  As described above, in the time exchange communication, the CPU and the wireless chip data line are monitored, the transmission delay time is measured, and the transmission delay time data indicating the measured transmission delay time is included in the time notification packet including the notification time data. Thus, both the notification time data and the transmission delay time data can be included in one time notification packet. For this reason, it is not necessary to separate the notification time data and the transmission delay time data from each other, and in the case of wireless communication, the notification time data has arrived at the reception side. The transmission delay time data reaches the receiving side, but conversely, the notification time data does not reach the receiving side due to packet loss, and the time error component due to wireless communication can be suppressed. And high-accuracy time exchange can be realized.

  In addition, the reception side measures the reception delay time and corrects the reception delay time to set the time, so the time error component due to wireless communication can be suppressed, and highly accurate time exchange is realized. it can.

  Further, since the transmission delay time data is replaced with the invalid area of the data field of the time notification packet, the wireless communication for the time exchange can be accommodated in one packet, and this packet can be received even in an unstable wireless environment. The receiving device that has been able to receive can synchronize the time.

  In addition, a measurement limit value is set for the timer, and if a stop notification cannot be received even after a longer time than the expected delay time, the measurement is forcibly terminated and an error notification is given. It is possible to prevent a measurement malfunction when receiving a packet other than time exchange.

The time exchange communication system according to the first embodiment is as follows.
(A). Time notifying means for ticking time and generating an alarm when an arbitrary time is reached (b). Time information transmission means for generating and wirelessly transmitting a wireless packet using the alarm occurrence time as data triggered by the alarm of (a). (C). Transmission delay measuring means for measuring a delay time from the alarm in (a) to the transmission of the wireless packet in (b) (d). (C) Transmission delay information transmitting means for generating and wirelessly transmitting a wireless packet using the delay time of (e). Time setting means for receiving the wireless packet of (b), extracting time information, and setting it in its own clock (f). (E) a reception delay measuring means for measuring a delay time from the reception of the wireless packet until the time is set; Time reception correction means for resetting by adding the delay time of (f) to the time of its own clock of (e) (h). (D) receiving a wireless packet, extracting transmission delay information, adding to the time of its own clock, and time transmission correcting means for resetting.

  Further, the wireless packets (b) and (d) are combined into one wireless packet.

  Further, as a combination of the above wireless packets, when generating (b) above, a data field for storing transmission delay information is provided in the packet in advance, and the transmission delay information is stored in this field. And

  Further, as a combination of the above-described wireless packets, the time information added with transmission delay information is converted into new time information.

  In addition, with respect to the combined wireless packet, data is separated and extracted into time information and transmission delay information on the receiving side.

  Further, the wireless packet is transmitted as a broadcast message.

  The transmission detection of the wireless packet in the above (c) is performed by detecting synchronization bit information included in the wireless packet.

  In the transmission delay measuring means in (b) above, an upper limit value detecting means is provided, and measurement is stopped when wireless transmission is not performed even after a predetermined time has elapsed.

  Further, in the reception delay measuring means in (f) above, an upper limit detecting means is provided, and the measurement is stopped when the time is not set even after a predetermined time has elapsed, and (g) and (h) The time is not set.

Embodiment 2. FIG.
In the first embodiment, the time exchange method based on the method of merging the transmission delay time data into the basic packet frame composed of the preamble, the synchronization signal, the data, and the end signal and outputting the result wirelessly is described. A method for exchanging time in a frame having an error detection or error correction code will be described.

  FIG. 8 is a diagram illustrating a configuration example of the wireless monitoring / control units 105 and 205 in the present embodiment.

  In FIG. 8, the error detection code generation unit 57 generates an error detection signal from the frame data sorted by the synchronization unit 51. The selector 58 selects a measurement value from the timer and an error detection code.

  FIG. 9 shows a frame format standardized by, for example, IEEE 802.15.4. 901 is a preamble, 902 is an SFD corresponding to a synchronization signal, 903 and 904 are header information, 905 is a payload corresponding to a data field, and 906 is an FCS which is an end signal and an error detection code. When this format is followed, the notification time data 907 and the transmission delay time data 908 are stored in the payload 905.

  Next, the operation will be described.

  The process until the transmission delay time is measured and the transmission delay time data is merged with the invalid area is the same as that of the first embodiment. In parallel with this, the radio monitoring / control unit 105 extracts data of the MHR 904 and the payload 905 by the synchronization unit 51, and generates an error detection code of this data by the error detection code generation unit 57. That is, before the transmission delay time data is merged, the error detection code is generated based on the packet contents that do not include the transmission delay time data. However, since the transmission delay time data is merged, the transmission delay time is Since it is necessary to regenerate the error detection code based on the packet content including the data, the error detection code generation unit 57 generates a new error detection code reflecting the packet content after the merge of the transmission delay time data. To do.

  The error detection code is, for example, a CRC code. Some specifications include an error correction code such as a Reed-Solomon code. In this case, the error detection code generation unit 57 similarly generates a new error correction code.

  When the frame control unit 52 detects the start of the invalid area in the payload 905 using the frame bit count by the synchronization unit, the frame control unit 52 sets the selector 58 to the timer measurement value output, and transmits the transmission delay time to the synthesis unit 106 through the output gate 56. Output data. When the start of FCS 906 is detected, the selector 58 is set to output an error detection code, and the newly generated error detection code is output to the synthesis unit 106. The synthesizing unit 106 replaces the value of the error detection code or error correction code of the time notification packet with the value of a new error detection code or error correction code output from the wireless monitoring / control unit 105, thereby delaying transmission to the invalid region. The error detection code or error correction code is updated by adding time data and changing the frame.

  As described above, even in a frame structure having an error detection code or error correction code, the error detection code or error correction code can be regenerated and replaced, so even in a wireless protocol based on a standardized frame specification The time exchange method can be added without changing the specifications.

  As described above, the time exchange communication system according to the second embodiment includes packet error detection or error correction bit generation means in addition to the combination of the radio packets shown in the first embodiment, and is added to the radio packet. The error detection or error correction bit is replaced.

  In each of the embodiments described above, the transmission device 100 and the reception device 200 can be realized by a computer.

  In the transmitting device 100 and the receiving device 200, for example, the CPU is connected via a bus to a ROM (Read Only Memory), a RAM (Random Access Memory), a flash memory, a communication board, a display device, a K / B (keyboard), a mouse. , FDD (Flexible Disk Drive), CDD (Compact Disk Drive), magnetic disk device, optical disk device, printer device, scanner device, and the like.

  The RAM is an example of a volatile memory. ROM, flash memory, FDD, CDD, magnetic disk device, and optical disk device are examples of nonvolatile memory.

  Data and information handled by the transmission device 100 and the reception device 200 according to each embodiment described above are stored in these storage units, and are recorded and read out by each unit of the transmission device 100 and the reception device 200.

  The magnetic disk device stores an operating system (OS), a window system, a program group, and a file group (database).

  The program group is executed by a CPU, OS, and window system.

  Each part of the transmission device 100 and the reception device 200 may be configured by a program that can be operated by a computer in part or in whole. Alternatively, it may be realized by firmware stored in the ROM. Alternatively, it may be implemented by software, hardware, or a combination of software, hardware, and firmware. For example, in the above embodiment, the wireless monitoring / control units 105 and 205 have been described as a hardware configuration, but may be configured as software that implements the same function, for example.

  The program group stores a program that causes the CPU to execute the processing described as “˜unit” in the description of the embodiment. These programs are created by computer languages, such as C language, HTML, SGML, and XML, for example.

  The program is stored in another recording medium such as a magnetic disk device, FD (Flexible Disk), optical disk, CD (compact disk), MD (mini disk), DVD (Digital Versatile Disk), and read by the CPU. And executed.

FIG. 3 is a diagram showing a system configuration example according to the first and second embodiments. FIG. 5 shows a configuration example of a transmission apparatus according to Embodiments 1 and 2. FIG. 5 shows a configuration example of a receiving apparatus according to Embodiments 1 and 2. FIG. 3 is a diagram illustrating a configuration example of a wireless monitoring / control unit according to the first embodiment. FIG. 4 shows a configuration example of a time notification packet according to the first embodiment. FIG. 3 is a flowchart showing an operation example of the transmission apparatus according to the first embodiment. FIG. 3 is a flowchart showing an operation example of the receiving apparatus according to the first embodiment. FIG. 6 is a diagram illustrating a configuration example of a wireless monitoring / control unit according to the second embodiment. FIG. 6 shows a configuration example of a time notification packet according to the second embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 100 Transmitter, 101 CPU, 102 Wireless chip, 103 Clock, 104 Timer, 105 Wireless monitoring / control unit, 106 Combining unit, 111 Alarm line, 112 Time data line, 113 Wireless transmission data line, 114 Stop signal line, 115 Measurement Data line, 116 Transmission delay time output line, 200 Receiver, 201 CPU, 202 Wireless chip, 203 Clock, 204 Timer, 205 Wireless monitoring / control unit, 212 Time data line, 214 Start signal line, 215 Measurement data line, 217 Wireless reception data line, 218 Stop signal line.

Claims (18)

A transmitting device for notifying a predetermined receiving device of a time,
A packet generator that generates a packet including notification time data indicating a notification time as a time notification packet;
A transmission delay time measurement unit that measures a transmission delay time that is a delay time in the transmission device;
A data synthesis unit that includes transmission delay time data indicating the transmission delay time measured by the transmission delay time measurement unit in a time notification packet;
A transmission apparatus comprising: a packet transmission unit configured to transmit a time notification packet including notification time data and transmission delay time data to the reception apparatus. The transmitting device further includes:
It has an alarm generation unit that ticks the time and generates an alarm at the notification time,
The packet generator is
Generating a time notification packet including time notification data indicating an alarm occurrence time, and outputting the generated time notification packet to the data synthesis unit;
The transmission delay time measuring unit is
The packet generation unit monitors whether the time notification packet is output to the data synthesis unit, detects the output of the time notification packet from the packet generation unit to the data synthesis unit, and detects the output of the time notification packet from the alarm occurrence time Until the transmission delay time is measured, and the transmission delay time data indicating the measured transmission delay time is output to the data synthesis unit,
The data synthesis unit
2. The time notification packet output from the packet generation unit and the transmission delay time data output from the transmission delay time measurement unit are input, and the transmission delay time data is included in the time notification packet. The transmitting device described. The packet generator is
Generating a time notification packet including a data field for storing transmission delay time data in the data synthesis unit;
The data synthesis unit
The transmission apparatus according to claim 1, wherein transmission delay time data is stored in the data field. The data synthesis unit
Adds the value of the notification time data and the value of the transmission delay time data, rewrites the notification time data included in the time notification packet to the addition value data, and uses the addition value data as the notification time data and the transmission delay time data as a time notification packet Included in
The packet transmitter is
The transmission apparatus according to claim 1, wherein a time notification packet including the added value data is transmitted to the reception apparatus. The packet generator is
Generate a time notification packet containing a predetermined synchronization signal,
The transmission delay time measuring unit is
The transmission apparatus according to claim 2, wherein a synchronization signal included in the time notification packet is detected, and output of the time notification packet from the packet generation unit to the data synthesis unit is detected. The transmission delay time measuring unit is
3. The transmission delay time measurement is stopped when output of a time notification packet from the packet generator to the data synthesizer cannot be detected even after a predetermined time has elapsed from an alarm occurrence time. The transmitting device described. The packet generator is
When generating a time notification packet, generate an error detection code or error correction code based on the notification time data, include the generated error detection code or error correction code in the time notification packet,
The transmitting device further includes:
When the transmission delay time is measured by the transmission delay time measurement unit, an error detection code generation unit that generates a new error detection code or error correction code based on the notification time data and the transmission delay time data,
The data synthesis unit
The error detection code or error correction code included in the time notification packet generated by the packet generation unit is rewritten with a new error detection code or error correction code generated by the error detection code generation unit. The transmission device according to claim 1. A receiving device that is notified of time from a predetermined transmitting device,
A packet receiving unit that receives a packet including notification time data indicating a notification time and transmission delay time data indicating a transmission delay time in the transmission device from the transmission device as a time notification packet;
A reception delay time measuring unit for measuring a reception delay time which is a delay time in the receiving device;
A time setting unit for setting the current time based on notification time data and transmission delay time data included in the time notification packet, and reception delay time data indicating the reception delay time measured by the reception delay time measurement unit; A receiving apparatus comprising: The receiving device further includes:
A data extraction unit that inputs a time notification packet from the packet reception unit, extracts notification time data and transmission delay time data from the time notification packet, and outputs the extracted notification time data and transmission delay time data to the time setting unit Have
The reception delay time measuring unit is
Monitoring whether or not a time notification packet is output from the packet reception unit to the data extraction unit; detecting an output of a time notification packet from the packet reception unit to the data extraction unit; and from the data extraction unit to the time setting unit The notification time data and the transmission delay time data are output from the data extraction unit to the time setting unit, and the notification time data and the transmission delay time data are detected from the data extraction unit. The time until the detection of the output of data and transmission delay time data is measured as the reception delay time, and the reception delay time data indicating the measured reception delay time is output to the time setting unit,
The time setting unit
The notification time data and transmission delay time data output from the data extraction unit and the reception delay time data output from the reception delay time measurement unit are input, and the notification time data, transmission delay time data and reception delay time data are input. 9. The receiving apparatus according to claim 8, wherein the current time is set based on the current time. The packet receiver
As the notification time data and the transmission delay time data, a time notification packet including addition value data indicating an addition value of the notification time and the transmission delay time is received,
The time setting unit
9. The receiving apparatus according to claim 8, wherein the current time is set based on the addition value data included in the time notification packet and the reception delay time data. The receiving device further includes:
A time extraction packet is input from the packet reception unit, the addition value data is extracted from the time notification packet, and the data extraction unit outputs the extracted addition value data to the time setting unit.
The reception delay time measuring unit is
Monitoring whether or not a time notification packet is output from the packet reception unit to the data extraction unit; detecting an output of a time notification packet from the packet reception unit to the data extraction unit; and from the data extraction unit to the time setting unit Monitoring whether or not addition value data is output, detecting the addition value data output from the data extraction unit to the time setting unit, and receiving the time from the detection of the output of the time notification packet to the detection of the addition value data output Measured as a delay time, and output reception delay time data indicating the measured reception delay time to the time setting unit,
The time setting unit
The addition value data output from the data extraction unit and the reception delay time data output from the reception delay time measurement unit are input, and the current time is set based on the addition value data and the reception delay time data. The receiving device according to claim 10. The packet receiver
Receive a time notification packet containing a predetermined synchronization signal,
The reception delay time measuring unit is
The receiving apparatus according to claim 9 or 11, wherein a synchronization signal included in the time notification packet is detected, and output of the time notification packet from the packet reception unit to the data extraction unit is detected. The reception delay time measuring unit is
When output of notification time data and transmission delay time data from the data extraction unit to the time setting unit cannot be detected even after a predetermined time has elapsed since detection of output of the time notification packet from the packet reception unit to the data extraction unit 10. The reception apparatus according to claim 9, wherein measurement of reception delay time is stopped. The reception delay time measuring unit is
If the output of the added value data from the data extraction unit to the time setting unit cannot be detected even after a predetermined time has elapsed since the detection of the output of the time notification packet from the packet reception unit to the data extraction unit, the reception delay time The reception apparatus according to claim 11, wherein the measurement of is stopped. A time notification method for notifying a predetermined receiving device of a time,
A packet generation step of generating a packet including notification time data indicating a notification time as a time notification packet;
A transmission delay time measuring step for measuring a transmission delay time which is a delay time related to packet generation and transmission;
A data synthesis step of including in the time notification packet transmission delay time data indicating the transmission delay time measured by the transmission delay time measuring step;
A time transmission method comprising: a packet transmission step of transmitting a time notification packet including notification time data and transmission delay time data to the receiving device. The time notification method further includes:
Having an alarm generation step of ticking time and generating an alarm at the notification time,
The packet generation step includes:
Generating a time notification packet including time notification data indicating an alarm occurrence time, and outputting the generated time notification packet to the data synthesis step;
The transmission delay time measuring step includes:
Whether the time notification packet is output from the packet generation step to the data synthesis step is monitored, the time notification packet output from the alarm generation step to the data synthesis step is detected, and the output of the time notification packet is detected from the alarm generation time Time is measured as a transmission delay time, and transmission delay time data indicating the measured transmission delay time is output to the data synthesis step,
The data synthesis step includes
16. The time notification packet output from the packet generation step and the transmission delay time data output from the transmission delay time measurement step are input, and the transmission delay time data is included in the time notification packet. The time notification method described. A time setting method for setting a time based on a time notified from a predetermined transmission device,
A packet receiving step of receiving a packet including notification time data indicating a notification time and transmission delay time data indicating a transmission delay time in the transmission device from the transmission device as a time notification packet;
A reception delay time measuring step for measuring a reception delay time which is a delay time related to packet reception and time setting;
A time setting step for setting the current time based on the notification time data and the transmission delay time data included in the time notification packet, and the reception delay time data indicating the reception delay time measured by the reception delay time measurement step; A time setting method characterized by comprising: The time setting method further includes:
A data extraction step of inputting a time notification packet from the packet reception step, extracting notification time data and transmission delay time data from the time notification packet, and outputting the extracted notification time data and transmission delay time data to the time setting step Have
The reception delay time measuring step includes:
Whether the time notification packet is output from the packet reception step to the data extraction step is monitored, the output of the time notification packet from the packet reception step to the data extraction step is detected, and further, from the data extraction step to the time setting step The notification time data and the transmission delay time data are monitored for output, the notification time data and the transmission delay time data are output from the data extraction step to the time setting step, and the notification time is detected from the detection of the output of the time notification packet. The time until detection of output of data and transmission delay time data is measured as a reception delay time, and reception delay time data indicating the measured reception delay time is output to the time setting step,
The time setting step includes
The notification time data and transmission delay time data output from the data extraction step and the reception delay time data output from the reception delay time measurement step are input, and the notification time data, transmission delay time data and reception delay time data are input. The time setting method according to claim 17, wherein the current time is set based on the current time.

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