JP2016116150A - Time synchronization device and communication network device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To minimize the influence of data delay amount in data transmission to a device connected to a network.SOLUTION: The time synchronization device comprises: an input part for receiving a transmission signal from a transmission device, separating the received transmission signal into a time timing signal and a data signal, and outputting the separated signals; an output part for receiving the time timing signal and the data signal outputted by the input part, and transmitting the time timing signal and the data signal; and a delay time calculation part for calculating a delay time of the time timing signal from inputting of the transmission signal to the input part till outputting the data signal and the time timing signal from the output part. The output part transmits the delay time calculated by the delay time calculation part together with the time timing signal and the data signal. In addition, a communication network device for performing transmission/reception of data signal between the transmission device and a reception device includes the time synchronization device provided between the transmission device and the reception device.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a time synchronization apparatus and a communication network apparatus using the apparatus.

  In the conventional technique, as shown in FIG. 7, when the time timing signal is distributed from the component 15 to the component 16, it passes through the two routers of the router 13 and the router 14 on the route. The processing of the time timing signal will be described with reference to FIG. The time timing signal is specified to perform data transmission with priority over other data. Therefore, when the time timing signal is distributed from the component 15 to the router 13, if the router 13 receives data from the component 17 other than the component 15, the data currently being processed can be interrupted inside the router 13. The processing is continued up to a certain unit, and when the data position at which interruption is possible is reached, the data transmitted by the component 17 is temporarily kept waiting, and the time timing signal that has been kept waiting is processed. After the time timing signal is processed, the data processing from the component 17 that has been suspended and resumed is resumed.

  Therefore, the standby time of the time timing signal differs depending on how far the data processed earlier is processed by the preceding data at the time of reception of the time timing signal. For example, when receiving the time timing signal, the router 13 processes the data from the other components 17 being received up to the shortest division point and waits for the time timing signal. At this time, the time timing signal has the shortest delay amount (delay time) TW1. Then, a time timing signal having a delay time TW 1 is transmitted to the next router 14. Since the router 14 performs the same operation, the time timing signal has the shortest delay time TW2 in the router 14. Thereby, the time timing signal can be received up to the component 16 with the minimum delay time. The above research is disclosed in the following literature.

Application and development status of Ushinren 55 1C06 SpaceWire to satellite development

  However, in the conventional technique, in the control of data output timing of a router or the like, jitter such as remaining processing of preceding data and a data delay time due to device design occur. Such a delay time is a fine delay time in the data transmission of the ground system, and there is no problem if it is a ground system. However, in the case of a system used in an artificial satellite, a ground observation of the cm level is performed and the speed of the satellite is 7.5 km / s or more, so even if the data delay time is several milliseconds. It becomes noise. That is, in a system used for an artificial satellite, a data delay time in data output control of a router or the like has been a serious problem.

  The present invention has been made to solve such a problem, and an object thereof is to provide a time synchronization apparatus and a communication network apparatus that can minimize the influence of data delay time in data transmission. .

The time synchronization device according to the present invention receives a transmission signal from a transmission device, separates the received transmission signal into a time timing signal and a data signal, and outputs an input of these separated signals,
An output unit for receiving and transmitting the data signal and the time timing signal output by the input unit;
A delay time calculation unit that calculates a delay time of the time timing signal from the input of the transmission signal to the input unit to the output of the data signal and the time timing signal from the output unit,
The output unit transmits the delay time calculated by the delay time calculation unit together with the time timing signal and the data signal.
The communication network device according to the present invention includes the time synchronization device provided between the transmission device and the reception device in order to transmit and receive data signals between the transmission device and the reception device. .

  According to the present invention, the influence of delay time in data transmission can be minimized.

1 is a configuration diagram of a communication network device according to an embodiment of the present invention. It is a block diagram which comprises 2N router which concerns on embodiment of this invention. It is a detailed block diagram which comprises the router which concerns on Embodiment 1 of this invention. It is a block diagram which comprises the output part of the router which concerns on Embodiment 1 of this invention. It is a figure which shows the timing which outputs the time timing signal which concerns on Embodiment 1 of this invention. It is a figure which shows the timing which outputs the time timing signal which concerns on Embodiment 1 of this invention. It is a block diagram of the communication network apparatus based on the conventional invention. It is a figure which shows the timing which outputs the time timing signal which concerns on the conventional invention.

Embodiment 1 FIG.
Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a conceptual diagram of a communication network that uses a time synchronization device between devices according to an embodiment of the present invention. In FIG. 1, 1, 2, 3, 4, and 5 are transmitting devices. Reference numeral 6 denotes a transmitting router connected to each transmitting device. Reference numeral 7 denotes a reception side router connected to the transmission side router 6. Reference numerals 8, 9, 10, 11, and 12 denote receiving devices connected to the receiving router 7. The transmitting router 6 and the receiving router 7 are referred to as time synchronization devices. The transmission devices 1, 2, 3, 4, 5 and the reception devices 8, 9, 10, 11, and 12 are collectively referred to as a component (Comp).

  Time timing compensation between a plurality of transmitting devices (components) 1, 2, 3, 4, 5 and a plurality of receiving devices (components) 8, 9, 10, 11, 12 via a serial interface such as SpaceWire. It is connected to routers 6 and 7 having functions. The router having the time timing compensation function here is called a time synchronizer. The transmission side router 6 and the reception side router 7 connect between networks, for example, packet transfer route selection from the transmission device, discard, route information management, and time synchronization correction processing.

  The transmitting device transmits a transmission signal. The transmission signal is composed of a time timing signal and a data signal. Here, the transmission device 1 (component 1) that outputs the time timing signal and the other transmission devices 2, 3, 4, and 5 (component 2 to component 5) are connected to the serial interface such as SpaceWire via the transmission side router 6. Connected with. The transmission side router 6 is further connected to the reception side router 7 via a serial interface such as SpaceWire. Similarly, the receiving side router 7 is connected to the receiving devices 8, 9, 10, 11, and 12 (component 8 to component 12) through a serial interface such as SpaceWire.

  The component 1 is assumed to output a time timing signal at regular time intervals. For example, a time timing signal is output once at intervals of 1 second. The components 2, 3, 4, and 5 normally output data signals. The components 8, 9, 10, 11, and 12 receive the time timing signal and the data signal from the receiving router 7. For example, the receiving device receives the time timing signal output from the component 1 and the data signal output from the components 2, 3, 4, and 5 via the transmission side router 6 and the reception side router 7.

  The configuration and operation of the time synchronizers of the transmitting router 6 and the receiving router 7 will be described with reference to FIGS. 2, 3, and 4. FIG.

  FIG. 2 is a block diagram showing a configuration of the routers 6 and 7 having a 2N channel time timing compensation function. Each router having a time timing compensation function includes an input unit, a relay unit, a delay time calculation unit, and an output unit. In FIG. 2, the input unit includes Input / Output port 1, Input / Output port 2,..., And Input / Output portN. Each Input / Output port enables bidirectional data transmission. The relay unit is a switch matrix, and input data from each input port is input to the designated output port. Further, when the Output port is already connected to another port, the output port is not released until the data transmission is completed, and enters the standby state. Since the time timing signal is transmitted with priority over normal data signal transmission, it is transmitted after transmission up to the minimum data transmission unit. The delay time calculation unit is a delay counter, and calculates a delay time from when the time timing signal is input to this router until it is output. The output unit includes Input / Output port N + 1, Input / Output port N + 2,..., And Input / Output port 2N. The delay time in this embodiment refers to the time from when the time timing signal is input to this router until it is output.

  The minimum transmission unit (or minimum data length) of data is the position of the minimum data at which data to be transmitted can be interrupted, or is determined by dividing the data by the data length n [bit].

  For example, if the minimum data length n is 10 bits, when the data signal for 3 bits is processed when the time timing signal from the component 1 is received by the router 6, the time timing signal is the remaining 7 bits. Wait for processing time. When processing of the 7-bit data signal is completed, the time timing signal is processed. At this time, the minimum transmission unit of data or the minimum division point at which data can be interrupted is 10 bits.

  FIG. 3 is a detailed block diagram configuring the routers 6 and 7 according to the first embodiment of the present invention. In order to eliminate redundant description, the configuration and operation of the router 6 will be described below. The configuration and operation of the router 7 are the same as those of the router 6. In FIG. 3, the router 6 or the router 7 includes an input unit (Input port), a common register 20, a relay unit 30, and an output unit (Output port). Here, the input unit will be described using the first input unit 10. The output unit will be described using the first output unit 40. Further, in FIG. 3, arrows between the components indicate the transmission directions of the data signal and the control signal.

  Of the time timing signals and data signals received by the first input unit 10, which is one of the configurations of the router 6, from the components 1 and 2, the first output unit 40 is designated by the data signal via the relay unit 30. Sent to. The first output unit 40 is also one of the configurations of the router 6. In the first input unit 10, the time timing signal is transmitted to the first output 40 unit via the common register 20. Here, the common register 20 and the relay unit 30 are connected by a plurality of input units and a plurality of output units.

  The first input unit 10 includes a serial-parallel conversion unit 11, a data identification unit 12, and a FIFO (Fisrt-In Fisher-Out) 13.

  The serial-parallel converter 11 receives a signal composed of a time timing signal and a data signal from a component and converts the signal from serial to parallel. Alternatively, the data is converted from serial to parallel.

  The data identification unit 12 identifies and separates the time timing signal and the data signal that have been converted from serial to parallel by the serial-parallel conversion unit 11. For example, it is identified whether the data is a normal data signal or control data such as a time timing signal, and the data signal and the time timing signal are separated.

  The FIFO 13 stores the data signal separated by the data identification unit 12. The FIFO 13 temporarily stores the data signal separated by the data identification unit 12, and outputs the data signal to the relay unit 30 after the storage. The FIFO 13 does not store a time timing signal or the like. The FIFO 13 processes data packets in the order of arrival. For example, the order is preserved at the time of entering and exiting such that the data entered first is processed first and the data entered later is processed after the data entered first.

  The common register 20 is a buffer for time timing signals separated by the data identification unit 12, and is connected to a plurality of input units and a plurality of output units. The common register 20 stores the time timing signal separated by the data identification unit 12 in the time timing signal buffer 200. Further, the common register 20 transmits time timing signals to a plurality of output units.

  The relay unit 30 is a switch matrix, and is connected to a plurality of input units and a plurality of output units. The relay unit 30 distributes data signals from a plurality of input units to designated output units. For example, the data signal from the first input unit 10 is transmitted to the designated first output unit 40.

  The first output unit 40 includes a delay information generation unit 41 and an output control unit 42.

  The delay information generation unit 41 receives time information and previous delay information from the time timing signal buffer 200. Also, an input unit delay time from when the time timing signal is input to the router input unit 10 to OFFSET until it is input to the time timing signal buffer 200 is set in advance, and the output unit delay detected by the output control unit 42 The result of adding the time and the previous delay information and the time information are output to the output control unit 42. In the first embodiment, the delay information generation unit 41 is one configuration of the first output unit 40, but is not limited to such a configuration, and may be a separate configuration.

  The output control unit 42 transmits the data signal received from the relay unit 30 and the delay time received from the delay information generation unit 41 to the receiving device. Further, based on the control signal received from the time timing signal buffer 200, a delay time from reception of the time timing signal at the first output 40 to transmission to the receiving device is calculated. This delay time is the output unit delay time.

  The output control unit 42 also receives control signals from the transmission rate 43 and the optimum operating frequency (FOT). The transmission rate 43 is a numerical value indicating how much data can be transmitted by a line or the like in a certain time.

  Hereinafter, the first output unit 40 will be described with reference to FIG.

  FIG. 4 is a block diagram showing the first output unit 40. As illustrated in FIG. 4, the delay information generation unit 41 includes a delay information unit 411 and a delay information addition unit 412. The delay information unit 411 detects an input unit delay time from the reception of the input unit to the common register 20 for the time timing signal received by the input unit. The delay information unit 411 adds the detected input unit delay time and the output unit delay time until the output of the time timing signal from the first output unit 40. This total value is transmitted to the control unit (MPX) 421 of the output control unit 42 via the delay information adding unit 412 as the input / output unit delay time.

  Further, the system shift is corrected based on a control signal from OFFSET connected to the delay information unit 411. Further, the delay information unit 411 can directly transmit the input / output unit delay time to the control unit (MPX) 421 of the output control unit 42.

  The delay information adding unit 412 receives the input / output unit delay time detected and calculated by the delay information unit 411. The delay information adding unit 412 receives the time timing signal from the time timing signal buffer 200 of the common register 20. Further, the delay information adding unit 412 selects addition of input / output delay time information by a delay information addition selection control signal. When adding an input / output delay time, information on the input / output delay time is output to the output control unit 42 via the delay information adding unit 412. When the input / output delay time information is not added, the input / output delay time information is directly delivered to the control unit 421 (MPX).

  For example, when the component connected to the first output unit 40 does not need the input / output delay time information, the input / output delay time information is not added. At this time, the delay information adding unit 412 is turned off. However, in this case, only the time timing signal is delivered from the delay information adding unit 412 to the control unit (MPX) 421. Information on the input / output delay time in this case is directly transmitted from the delay information unit 411 to the control unit (MPX) 421 as normal data.

  On the other hand, when the component connected to the first output unit 40 requires delay time information, the delay time information is added. At this time, the delay information adding unit 412 is turned on. At this time, the delay information adding unit 412 outputs the time timing signal and the delay time information to the control unit (MPX) 421.

  As described above, the delay information addition selection function can cope with each of the components that do not require or need delay time information because the delay information addition unit 412 is switched between the ON state and the OFF state.

  The output control unit 42 includes a control unit (MPX) 421, a data selection unit 422, a delay amount calculation unit 423, and a parallel-serial conversion unit 424. The output control 42 can detect the minimum data length of the data signal based on the transmission rate 43. When receiving the time timing signal, if the data signal is received, the data signal being received is received up to the minimum data length, and then the time timing signal and delay time information are received. The same applies to the transmission. When a data signal is transmitted, the data signal being transmitted is transmitted up to the minimum data length, and then the time timing signal and delay time information are distributed. Finally, the remaining data signal is distributed.

  An MPX (Multiplexer) 421 is an input data selection unit, and includes information on the time timing signal and input / output delay time transmitted by the delay information adding unit 412, delay information output from the delay information unit 411, and the relay unit 30. Select from data input. For example, when a time timing signal is distributed during reception of data, the time timing signal is received after reception from that time until the minimum data length of the data being received. After distributing the time timing signal, reception of data from the relay unit 30 is resumed.

  The MPX 421 also receives a NULL signal. NULL is a signal received from a node connected to the output port 40.

  The data selection unit 422 receives a control signal for transmitting the time timing signal from the time timing signal buffer 200. Thereby, the data selection unit 422 outputs a control signal for notifying the MPX 421 and the delay amount calculation unit 423 that the time timing signal is received.

  The delay amount calculation unit 423 calculates a delay time from the input to the output of the time timing signal in the first output unit 40. The calculated delay time is output to the delay information unit 411. For example, the minimum data length of data transmission can be determined by a control signal from the data signal transmission rate 43. The delay time until the output of the time timing signal in the first output unit 40 counts the reception time of data from the data received by the MPX 421 to the minimum data length according to the determined minimum data length.

  The parallel-serial conversion unit 424 is an output unit. A time timing signal, a delay time information signal, and a data signal from the MPX 421 are converted from parallel to serial. A time timing signal, a delay time information signal, and a data signal converted by a data transmission control signal from the transmission rate 43 and the FOT are output to a receiving device.

  On the other hand, since the time timing signal performs broadcast communication to all ports, the port in use is in a standby state. The standby time for each port is calculated by the delay information generation unit 41 and the output control unit 42 on the respective port output side. In the first embodiment, the above connection is not limited.

  Hereinafter, it will be described with reference to FIGS. 5 and 6 that data is processed in a minimum transmission unit.

  FIG. 5 is a schematic diagram showing that information on the input / output delay time is added to the time timing signal according to the first embodiment. In FIG. 1, component 1 and component 2 output a time timing signal and a data signal to router 6. It is assumed that a time timing signal is output from the component 1 at regular intervals, for example, at intervals of 1 second. The output time timing signal is received and input by the router 6. The router 6 receives time timing signals and data signals from the components 2, 3, 4, and 5 connected to the router 6. At the same time, the time timing signal and the data signal transmitted from the router 6 to the router 7 are transmitted to the components 8, 9, 10, 11 and 12 connected to the router 7. FIG. 5 is a diagram showing signal processing and operation in the router 6 in order to transmit a data signal and a time timing signal from the router 6 in FIG. 1 to the router 7.

  As shown in FIGS. 5A to 5B, the router 6 receives a time timing signal from the component 1, for example. Upon reception, the router 6 continues processing the data signal received from the component 2 currently being processed, for example, up to the minimum data length (minimum data transmission unit or interruptable position). The router 6 temporarily waits for processing of the data signal from the component 2 when reaching the data that can be interrupted. Here, the time that the previously processed data signal processes from the time of reception of the time timing signal to the minimum data length of the data signal is the waiting time of the time timing signal.

  As shown in FIGS. 5B to 5C, for example, the router 6 temporarily waits for the data signal from the component 2 and processes the time timing signal that has been waiting. The router 6 processes the delay time generated inside the router 6 after processing the time timing signal. Finally, the router 6 processes the remaining data signal among the data signals from the component 2.

  Therefore, the standby time of the time timing signal differs depending on how far the data signal that has been processed earlier is processed before the time signal is received. For example, the minimum data length of the data signal output from the component 2 is 10 bits, or the division point is 10 bits. In this case, as shown in FIG. 5A, when the router 6 receives the time timing signal therein, the data signal processed by the router 6 has already been processed for 4 bits. In this case, the time timing signal waits for the remaining 6 bits of processing time and is transmitted to the router 7. If the data signal being processed is processed for 3 bits, the time timing signal waits for the remaining 7 bits to be processed.

  FIG. 6 is a schematic diagram showing that a physical delay time independent of the time timing signal according to the first embodiment is output as an information packet. The description of the internal processing of the router 6 that is the same as in FIG. 5 will be omitted. 6 (c) to 6 (d), the processing time of the time timing signal and the data signal that has been put on standby are processed after the time timing signal is processed. Finally, the physical delay time is added inside the router 6, processed as an information packet, and transmitted to the router 7.

  In the first embodiment, the delay time is calculated in the router 7 in the same manner. As shown in FIG. 1, this delay time is output to the components 8 to 12 connected to the first output unit 40. The components 8 to 12 perform time correction based on the time timing signal and the delay time. The components 8 to 12 correct the time counter and the like by the time management function. Alternatively, correction is performed when the time timing signal is used. At this time, for a component that requires delay time information, the delay time information addition method is set from the component connected to the first input unit 10. For example, there is an output method in which delay time information is added to a time timing signal as shown in FIG. Further, there is a method of outputting the delay time information as shown in FIG. 6 as an information packet.

  When the components 8 to 12 do not correct the time, the received delay time information is sent back to the components 1 to 5, and the delay time at that time is treated as normal data and passes through the router 6 and the router 7. No delay time is added. At this time, the router has a delay amount information packet switching function ON / OFF.

  In addition, in order to achieve time synchronization with higher accuracy, each component receives network topology information including the line length between components and data transmission rate from each component. The time is calculated from the line length and the data transmission rate, added to the received delay time information, and used for time correction.

  According to this embodiment, the device connected to the router on the communication network can set the time correction of the time timing signal more accurately and easily, thereby improving the accuracy of the satellite mission. be able to.

  The present invention can be used for a router having a time timing compensation function for transmitting information and a communication network device using the device.

DESCRIPTION OF SYMBOLS 100 Transmission system, 1-5, 8-12 component, 6 router, 7 router, 10 1st input part, 11 serial-parallel conversion part, 12 data identification part, 13 FIFO (Fisrt-In Firet-Out), 20 common register , 200 time timing signal buffer, 30 relay unit (Switch Matrix), 40 first output unit, 41 delay information generation unit, 411 delay information addition unit, 412 delay information addition unit, 42 output control unit, 421 control unit (MPX) ) 422 Data selection unit, 423 Delay amount calculation unit (Delay Counter), 424 Parasiri conversion unit, 43 Transmission rate

Claims (3)

An input unit that receives a transmission signal from a transmission device, separates the received transmission signal into a time timing signal and a data signal, and outputs these separated signals;
An output unit for receiving and transmitting the data signal and the time timing signal output by the input unit;
A delay time calculation unit that calculates a delay time of the time timing signal from the input of the transmission signal to the input unit to the output of the data signal and the time timing signal from the output unit;
The time synchronization apparatus, wherein the output unit transmits the delay time calculated by the delay time calculation unit together with the time timing signal and the data signal. In a communication network device that transmits and receives data signals between a transmitting device and a receiving device,
A communication network comprising the time synchronization device according to claim 1 provided between the transmission device and the reception device, and performing data communication between the transmission device and the reception device. apparatus. When the receiving device performs time correction for time management, it performs time correction based on the input / output unit delay time received from the time synchronization device,
The communication network device according to claim 2, wherein when the time is not corrected, the received input / output unit delay time is transmitted to the transmitting device.

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