WO2023243031A1 - Optical tdm transmission device, synchronization method, and synchronization program - Google Patents

Optical tdm transmission device, synchronization method, and synchronization program Download PDF

Info

Publication number
WO2023243031A1
WO2023243031A1 PCT/JP2022/024087 JP2022024087W WO2023243031A1 WO 2023243031 A1 WO2023243031 A1 WO 2023243031A1 JP 2022024087 W JP2022024087 W JP 2022024087W WO 2023243031 A1 WO2023243031 A1 WO 2023243031A1
Authority
WO
WIPO (PCT)
Prior art keywords
signal
timing
timing signal
optical
tdm transmission
Prior art date
Application number
PCT/JP2022/024087
Other languages
French (fr)
Japanese (ja)
Inventor
公太 西山
雅弘 中川
佳奈 益本
俊哉 松田
剛志 関
Original Assignee
日本電信電話株式会社
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 日本電信電話株式会社 filed Critical 日本電信電話株式会社
Priority to PCT/JP2022/024087 priority Critical patent/WO2023243031A1/en
Publication of WO2023243031A1 publication Critical patent/WO2023243031A1/en

Links

Images

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L12/00—Data switching networks
    • H04L12/28—Data switching networks characterised by path configuration, e.g. LAN [Local Area Networks] or WAN [Wide Area Networks]
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L12/00—Data switching networks
    • H04L12/28—Data switching networks characterised by path configuration, e.g. LAN [Local Area Networks] or WAN [Wide Area Networks]
    • H04L12/42—Loop networks
    • H04L12/427—Loop networks with decentralised control
    • H04L12/43—Loop networks with decentralised control with synchronous transmission, e.g. time division multiplex [TDM], slotted rings
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L12/00—Data switching networks
    • H04L12/28—Data switching networks characterised by path configuration, e.g. LAN [Local Area Networks] or WAN [Wide Area Networks]
    • H04L12/44—Star or tree networks

Definitions

  • the present invention relates to an optical TDM transmission device, a synchronization method, and a synchronization program.
  • TDM time division multiplexing
  • FIG. 19 is an explanatory diagram showing signals used in optical TDM transmission and signals used in a normal transmission network.
  • the signal 801 is a "continuous signal” in which a single signal occupies the same line and the same wavelength transmission path. Continuous signals are optical signals used in existing link systems.
  • the signal 802 is a "burst signal” in which a plurality of signals are divided by a fixed time width (time slot: TS) on the time axis on the same line and the same wavelength transmission path.
  • TS time slot
  • a burst signal is an optical signal that is intermittent on the time axis, and in TDM transmission, data is superimposed on this burst signal and transmitted. Between burst signals, there is a no-signal period (guard time: GT) in which the optical power is approximately 0.
  • multiple nodes (transmission equipment) connected on the same line transmit burst signals on the same wavelength at different times to avoid collisions between signals.
  • a state in which burst signals can reach the destination receiving end without colliding with each other is called a synchronous state.
  • PON Passive Optical Network
  • OLT Optical Line Terminal
  • ONU Optical Network Unit
  • P2MP Point to Multi-point
  • FIG. 15 is a configuration diagram of the TDM-PON system described in Non-Patent Document 1.
  • an OLT is connected to each ONU through an optical fiber.
  • Optical fibers from the OLT are branched to each ONU via an optical splitter SP.
  • the signal flow from the OLT to the ONU will be referred to as a "downstream signal”
  • the signal flow from the ONU to the OLT will be referred to as an "upstream signal.”
  • FIG. 16 is a sequence diagram showing the signal flow in the TDM-PON system of FIG. 15.
  • the OLT transmits a downlink continuous signal for RTT measurement to the ONU at time t0.
  • the destination ONU sets the time to t0 at the timing of receiving the downlink continuous signal from the OLT (S11).
  • the ONU transmits an uplink burst signal for RTT measurement at time t1 specified by the OLT.
  • the OLT obtains time t2 at which the uplink burst signal is received (S12). Thereby, the OLT calculates the RTT with the ONU based on the timestamps from time t0 to t2.
  • the OLT transmits the transmission timing of a data signal using burst light to the ONU (S13).
  • the ONU transmits a data signal using burst light based on the notified timing (S14).
  • FIG. 17 is a configuration diagram of a TDM-PON system in a 1-to-N optical connection (P2MP optical connection) network described in Non-Patent Documents 1 and 2.
  • a continuous down signal P11 from the OLT to each ONU and a signal P13 in which the up burst signal P12 from each ONU to the OLT is multiplexed propagate between nodes.
  • the downlink signal P11 is, for example, a Sync signal (S11) and a timing notification signal (S13) used in the RTT measurement in FIG. 16.
  • the upstream signal P12 is, for example, the Sync signal (S12) in FIG. 16 and the data signal (S14) addressed to another ONU.
  • the OLT achieves synchronization accuracy of several tens to hundreds of nanoseconds by measuring RTT every time each ONU transmits and receives a data signal (S14).
  • FIG. 18 is a configuration diagram of a TDM-PON system in an N-to-M optical connection network.
  • the set be the receiving side of the Metro network.
  • the transmitting side ONU corresponds to the ONU that is the transmitting source of the data signal P12.
  • the receiving side ONU refers to an ONU that receives the data signal P13.
  • FIG. 20 is an explanatory diagram of the transmission cycle of TDM transmission.
  • Time slots are divided into periods T and assigned to each ONU. This period is called the TDM frame length.
  • a first ONU may transmit one data signal in a first period T and another data signal in a next period T.
  • the GT provided between time slots plays the role of absorbing signal deviations (synchronization errors).
  • FIG. 21 is an explanatory diagram of signal collision of burst signals flowing from left to right.
  • a first data signal 811A, a second data signal 811B, and a third data signal 811C are sequentially superimposed on the optical fiber.
  • the time slot of the first data signal 811A and the time slot of the second data signal 811B partially overlap, resulting in signal collision.
  • a first data signal 812A, a second data signal 812B, and a third data signal 812C are sequentially superimposed onto the optical fiber.
  • the time slots of each data signal can be correctly superimposed without overlapping.
  • the main objective of the present invention is to avoid collisions between data signals during multiplexing without measuring the RTT for each node in an optical TDM transmission network with N-to-M optical connections.
  • the optical TDM transmission device of the present invention has the following features.
  • the present invention provides an optical TDM transmission system in which a plurality of optical TDM transmission devices transmit data signals while synchronizing time slots between nodes.
  • Each of the optical TDM transmission devices includes: receiving a timing signal having different physical properties from the data signal, storing the reception time and reception period of the received timing signal as the reception timing of the timing signal; The data signal transmitted from itself is controlled to be superimposed on a time slot grasped based on the stored reception timing.
  • collisions between data signals during multiplexing can be avoided without measuring RTT for each node in an N-to-M optical connection network.
  • FIG. 1 is a configuration diagram of an optical TDM transmission system in an N-to-M optical connection network according to the present embodiment.
  • FIG. 2 is a configuration diagram when the N-to-M optical connection network of FIG. 1 according to the present embodiment is applied to a network having a ring topology.
  • FIG. 4 is an explanatory diagram of time slots forming the burst signal of FIG. 3 according to the present embodiment. It is a block diagram of the T transmitter regarding this embodiment.
  • FIG. 3 is a time-series time slot diagram showing a timing signal extraction method according to the present embodiment.
  • FIG. 7 is a time slot diagram in which a part of FIG. 6 is enlarged according to the present embodiment.
  • FIG. 1 is a configuration diagram of a TDM-PON system described in Non-Patent Document 1.
  • FIG. 16 is a sequence diagram showing the flow of signals in the TDM-PON system of FIG. 15.
  • FIG. 1 is a configuration diagram of a TDM-PON system in a 1-to-N optical connection (P2MP optical connection) network described in Non-Patent Documents 1 and 2.
  • FIG. FIG. 1 is a configuration diagram of a TDM-PON system in an N-to-M optical connection network.
  • FIG. 2 is an explanatory diagram showing signals used in optical TDM transmission and signals used in a normal transmission network.
  • FIG. 2 is an explanatory diagram of a transmission cycle of TDM transmission.
  • FIG. 3 is an explanatory diagram of signal collision of burst signals flowing from left to right.
  • FIG. 1 is a configuration diagram of an optical TDM transmission system in an N-to-M optical connection network.
  • This TDM transmission system is an example of an optical TDM system in which a plurality of nodes transmit data signals while synchronizing time slots between the nodes.
  • the TDM transmission system in FIG. 1 includes a T (Timing) transmitter 30 instead of the OLT that measures RTT with each ONU on the transmitting side (2-way synchronization processing) in FIG. 18.
  • the T transmitter 30 transmits a timing signal P15 to each node on the transmitting side using one time slot on the same wavelength as the data signal.
  • Each node on the transmitting side receives the timing signal P15 and stores therein the reception time and reception period of the received timing signal P15 as the reception timing.
  • the T transmitter 30 transmits the timing signal P15 which has different physical properties such as intensity and time slot width from the data signal P12. .
  • the timing signal P15 having different physical properties is a signal exemplified below. ⁇ Timing signal P15 whose optical power (intensity) is different from that of data signal P12 ⁇ Timing signal P15 whose time slot width (TS width) is different from that of data signal P12
  • Each node receives a timing signal P15 having different physical properties from the data signal P12, and stores the reception time and reception period of the received timing signal P15 as the reception timing of the timing signal P15. Further, each node controls the data signal P12 transmitted from itself to be superimposed on the time slot determined based on the stored reception timing. Further, even after the reception timing is stored, each node receives the timing signal P15 transmitted to each node, and corrects the stored reception timing based on the received timing signal P15.
  • each node can extract a signal having different physical properties by regarding it as the timing signal P15.
  • each node can grasp the accidental deviation of the timing signal P15 at the physical layer and correct the deviation. Therefore, by having each node detect the timing signal P15 superimposed on the optical path for transmitting and receiving signals at the physical layer, even if the synchronization state of time slots between nodes is interrupted for some reason, the timing signal P15 superimposed on the optical path for transmitting and receiving signals can be detected again. By simply receiving the signal P15, it is possible to re-establish a highly accurate synchronization state. Furthermore, a burst signal P13 in which the timing signal P15 and the data signal P12 are superimposed at the same wavelength flows on the optical path. Each node on the receiving side can refer to the physical properties of the received burst signal P13 and extract the desired data signal P13 while discarding the timing signal.
  • FIG. 2 is a configuration diagram when the N-to-M optical connection network of FIG. 1 is applied to a network having a ring topology.
  • three nodes are placed on the left side of the drawing as the transmitting side, and three nodes are placed on the right side of the drawing as the receiving side.
  • four nodes are placed on the left side of the drawing as transmitters, and five nodes are placed on the right side of the drawing as receivers.
  • the T transmitter 30 transmits a timing signal T to the four nodes on the transmitting side. That is, the starting point of the timing signal T is the T transmitter 30 in both FIG. 1 and FIG.
  • the four nodes on the transmitting side superimpose the data signal D on the timing signal T.
  • the five nodes on the receiving side receive the timing signal T and the data signal D.
  • FIG. 4 is an explanatory diagram of time slots forming the burst signal P13 of FIG. 3.
  • Reference numeral 101 is a time slot of wavelength ⁇ 1 at the time when the T transmitter 30 first transmits the timing signal T. Each node receives a timing signal T. A timing signal T is periodically inserted according to a signal-specific pattern indicated by reference numeral 103, and the other time slots are empty slots.
  • Reference numeral 102 is a time slot of wavelength ⁇ 1 at the time when a certain node transmits (superimposes) a data signal as a burst signal (burst light) to the empty slot 101.
  • FIG. 5 is a configuration diagram of the T transmitter 30.
  • the T transmitter 30 includes a clock section 31, a counter management section 32, a control section 33, and a timing signal transmission section 34.
  • the clock section 31 supplies a clock to the counter management section 32.
  • the counter management unit 32 counts the time from transmitting a timing signal until transmitting the next timing signal as a counter value based on the clock from the clock unit 31.
  • the control section 33 controls the timing signal transmission section 34 to transmit the timing signal based on the counter value notified from the counter management section 32.
  • the timing signal transmitter 34 transmits a timing signal under the control of the controller 33.
  • processing of timing signals having different optical powers will be described as an example of physical properties different from data signals.
  • the outline of processing of timing signals having different powers is as follows (Processing 1A) to (Processing 3A).
  • Processcess 1A During the preparation period, the T transmitter 30 causes each node to store the power threshold of the timing signal by transmitting a timing signal with a power different from that of the data signal to each node.
  • Processcess 2A During the operation period, the T transmitter 30 transmits the same timing signal as the preparation period to each node. Each node can distinguish whether a received signal is a data signal or a timing signal using the stored power threshold as a clue.
  • FIG. 6 is a time-series time slot diagram showing a timing signal extraction method.
  • FIG. 7 is a time slot diagram in which a part of FIG. 6 is enlarged.
  • the coloring pattern of each signal is the same as the reference numeral 103 in FIG.
  • the T transmitter 30 transmits a timing signal whose optical power is larger than the data signal (longer in the upward direction in the figure) at every predetermined timing T0.
  • Each node compares the power of each signal received on the same wavelength with a predetermined power threshold, and considers a signal above the predetermined power threshold to be a new timing signal, and a signal below the predetermined power threshold to be a data signal. I reckon. Then, each node sets a reference (reception timing) for superimposing the data signal based on the new timing signal.
  • each node receives only the timing signal from the T transmitter 30 during the preparation period before transmitting and receiving the data signal, and sets the power (such as the average value) of the received timing signal as a predetermined power threshold. It is desirable to keep it.
  • each node may directly receive input from an administrator or the like using a predetermined power threshold as setting data. This preparation period threshold setting process can be applied not only to the optical power threshold but also to the setting of other physical property thresholds such as the TS width threshold.
  • each node may modify the criteria for superimposing data signals if it receives a new timing signal that exceeds a predetermined power threshold.
  • FIG. 8 is a configuration diagram of the node 50.
  • These nodes 50 are, for example, three transmitting nodes arranged on the left side of FIG. 1, and four transmitting nodes arranged on the left side of FIG.
  • the node 50 includes a burst light receiving section 51, a TIA (trans impedance amplifier) 52, a voltage detection circuit section 53, a control section 54, a TS (Time Slot) control section 55, a counter management section 56, and a clock section. 57, and a burst light transmitter 58.
  • the burst light receiving section 51 receives burst light (burst signal) including a timing signal.
  • the TIA 52 converts the current value of the burst signal into a voltage value.
  • the voltage detection circuit section 53 monitors the waveform level of the converted voltage value, notifies the control section 54 of signals exceeding a predetermined power threshold as timing signals, and controls signals below the predetermined power threshold as data signals. Department 54.
  • the control unit 54 receives the timing signal of the preparation period and sets a predetermined power threshold calculated from the timing signal in the voltage detection circuit unit 53. Then, the control unit 54 notifies the TS control unit 55 and the counter management unit 56 of the reception timing obtained from the timing signal notified during the operation period. Furthermore, the control unit 54 may receive a new timing signal and correct the previously stored reception timing. Based on the reception timing notified from the control unit 54, the TS control unit 55 controls the time slot in which the signal transmitted by its own device is superimposed so as to avoid collision with other signals. The counter management section 56 notifies the control section 54 and the TS control section 55 of the counter value. As explained in FIG. 5, the counter value indicates the time from transmitting a timing signal to transmitting the next timing signal. The clock unit 57 supplies a clock to the counter management unit 56. The burst light transmitter 58 superimposes an arbitrary signal on the TS designated by the TS controller 55 and transmits a data signal.
  • the burst light receiving unit 51 receives burst light and converts it into an electrical signal (O/E conversion) (S112).
  • the TIA 52 converts the current value of the electrical signal into a voltage value (S122).
  • the voltage detection circuit section 53 notifies the control section 54 of the time response (timing signal) of the voltage value exceeding the threshold value (S132).
  • the control unit 54 notifies the counter management unit 56 of the reception timing of the timing signal (S143).
  • the clock section 57 supplies a clock (S161).
  • the counter management unit 56 starts a counter (S151).
  • the control unit 54 notifies the TS control unit 55 of the time slot reference (reception timing) (S144).
  • the counter management unit 56 notifies the TS control unit 55 of a counter value indicating the time from receiving a timing signal to receiving the next timing signal (S152).
  • the TS control unit 55 determines a TS (time slot) on which a Data signal is to be superimposed (S171).
  • the burst light transmitter 58 superimposes an arbitrary signal on the TS designated by the TS controller 55 and transmits a data signal (S181).
  • Each node can distinguish whether a received signal is a data signal or a timing signal using the stored TS width as a clue.
  • the reception timing of the received timing signal is used as a reference for the data signal to be transmitted (which TS to superimpose on).
  • each node corrects the standard (reception timing) of the data signal in (Process 2B) based on the received timing signal.
  • FIG. 10 is a time-series time slot diagram showing a timing signal extraction method.
  • FIG. 11 is a time slot diagram in which a part of FIG. 10 is enlarged.
  • the coloring pattern of each signal is the same as the reference numeral 103 in FIG.
  • the T transmitter 30 transmits a timing signal whose TS width is narrower than the data signal (shorter in the left and right time axis directions in the figure) at every predetermined timing T0. Furthermore, each node superimposes data signals after a certain guard time (GT).
  • GT guard time
  • Each node compares the TS width of each signal received on the same wavelength with a predetermined TS width threshold, considers a signal that is less than the predetermined TS width threshold as a new timing signal, and treats a signal that is greater than or equal to the predetermined TS width threshold as a new timing signal. is regarded as a data signal. Then, each node sets a standard for superimposing data signals based on the new timing signal.
  • FIG. 12 is a configuration diagram of the node 50B.
  • the voltage detection circuit section 53 when compared with the node 50 in FIG. 8, the voltage detection circuit section 53 is replaced with a TS width detection circuit section 53B.
  • the TS width detection circuit unit 53B monitors the TS width of the converted voltage value, notifies the control unit 54 of a signal that is less than a predetermined TS width (pulse width) threshold as a timing signal, and notifies the control unit 54 of a signal that is less than a predetermined TS width (pulse width) threshold.
  • the control unit 54 is notified of the signal as a data signal.
  • the control unit 54 receives the timing signal of the preparation period and sets a predetermined TS width threshold calculated from the timing signal in the TS width detection circuit unit 53B.
  • the processing contents of each other processing unit are as described in FIG. 8.
  • FIG. 13 is a sequence diagram showing the operation of node 50B in FIG. 12.
  • the burst light receiving unit 51 receives burst light and converts it into an electrical signal (O/E conversion: Optical/Electrical conversion) (S211).
  • the TIA 52 converts the current value of the electrical signal into a voltage value (S221).
  • the clock section 57 supplies a clock to the TS width detection circuit section 53B (S261).
  • the TS width detection circuit unit 53B measures the TS width based on the time response of the voltage value, and notifies the control unit 54 of the measurement result (S231).
  • the control unit 54 grasps the TS width value of the timing signal (S241).
  • the control unit 54 determines the TS width that is a trigger and notifies the TS width detection circuit unit 53B (S242).
  • the burst light receiving unit 51 receives burst light and converts it into an electrical signal (O/E conversion) (S212).
  • the TIA 52 converts the current value of the electrical signal into a voltage value (S222).
  • the TS width detection circuit unit 53B extracts a signal (timing signal) that is less than or equal to the specified TS width, and notifies the control unit 54 of the timing signal (S232).
  • the control unit 54 grasps the reception time (reception timing) of the timing signal, and notifies the counter management unit 56 of the reception time (S243).
  • the clock section 57 supplies a clock to the counter management section 56 (S262).
  • the counter management unit 56 starts a counter (S251).
  • the control unit 54 notifies the TS control unit 55 of the reception timing (S244).
  • the counter management unit 56 notifies the TS control unit 55 of a counter value indicating the time from receiving a timing signal to receiving the next timing signal (S252).
  • the TS control unit 55 determines the TS (time slot) on which the Data signal is to be superimposed (S271).
  • the burst light transmitter 58 superimposes an arbitrary signal on the TS specified by the TS controller 55 and transmits a data signal (S281).
  • FIG. 14 is a hardware configuration diagram of an optical TDM transmission device (node 50 in FIG. 8 and node 50B in FIG. 12).
  • the optical TDM transmission device is configured as a computer 900 having a CPU 901, a RAM 902, a ROM 903, an HDD 904, a communication I/F 905, an input/output I/F 906, and a media I/F 907.
  • the T transmitter 30 in FIG. 5 is similarly configured as a computer 900.
  • Communication I/F 905 is connected to external communication device 915.
  • the input/output I/F 906 is connected to the input/output device 916.
  • the media I/F 907 reads and writes data from the recording medium 917.
  • the CPU 901 controls each unit by executing a program (also called an application or an abbreviated application) read into the RAM 902 .
  • This program can also be distributed via a communication line or recorded on a recording medium 917 such as a CD-ROM.
  • the present invention provides an optical TDM transmission system in which a plurality of nodes 50 transmit data signals while synchronizing time slots between the nodes.
  • Each node 50 is Receive a timing signal that has physical properties different from the data signal, and store the reception time and reception period of the received timing signal as the reception timing of the timing signal, It is characterized by controlling the data signal transmitted from itself to be superimposed on the time slot grasped based on the stored reception timing.
  • each node 50 can quickly determine whether a timing signal is a timing signal or not by measuring the power of the physical layer without referring to the signal content of the timing signal.
  • each node 50 receives a timing signal having a different time slot width from that of the data signal, as a timing signal whose physical properties are different from that of the data signal.
  • each node 50 can quickly determine whether a timing signal is a timing signal or not by measuring the time slot width of the physical layer without referring to the signal content of the timing signal.
  • each node 50 receives a timing signal transmitted to each node 50 even after the reception timing is stored, and corrects the stored reception timing based on the received timing signal. It is characterized by

Landscapes

  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Optical Communication System (AREA)
  • Synchronisation In Digital Transmission Systems (AREA)

Abstract

An optical time-division-multiplexing (TDM) transmission system in which a plurality of nodes (50) transmit data signals in a state in which time slots between the nodes are synchronized, wherein each of the nodes (50) receives a timing signal that differs in physical characteristics from the data signals, stores the reception time and reception cycle of the received timing signal as a reception timing of the timing signal, and performs control such that a data signal transmitted from the node itself is superimposed in a time slot that is ascertained with reference to the stored reception timing.

Description

光ＴＤＭ伝送装置、同期方法、および、同期プログラムOptical TDM transmission device, synchronization method, and synchronization program
　本発明は、光ＴＤＭ伝送装置、同期方法、および、同期プログラムに関する。 The present invention relates to an optical TDM transmission device, a synchronization method, and a synchronization program.
　伝送網における複数もの通信局舎間をフルメッシュ光接続するためには、光パス数の拡大が求められる。光パス数の拡大を実現する一技術として、光時分割多重（ＴＤＭ：Time Division Multiplexing）が有効である。 In order to establish full-mesh optical connections between multiple communication stations in a transmission network, it is necessary to increase the number of optical paths. Optical time division multiplexing (TDM) is an effective technique for increasing the number of optical paths.
　図１９は、光ＴＤＭ伝送で使用する信号と通常の伝送網で使用される信号を示した説明図である。
　信号８０１は、同一回線かつ同一波長の伝送路を、単一の信号が占有する「連続信号」である。連続信号は、既存のリンクシステムで用いられる光信号である。
　信号８０２は、同一回線かつ同一波長の伝送路を、複数の信号が時間軸上で区切られた固定の時間幅（タイムスロット：TS）で分割された「バースト信号」である。バースト信号は、時間軸上で間欠的な光信号であり、ＴＤＭ伝送では、このバースト信号にデータを重畳して伝送する。バースト信号間には、光パワーがほぼ０である無信号区間（ガードタイム:GT）が存在する。 FIG. 19 is an explanatory diagram showing signals used in optical TDM transmission and signals used in a normal transmission network.
The signal 801 is a "continuous signal" in which a single signal occupies the same line and the same wavelength transmission path. Continuous signals are optical signals used in existing link systems.
The signal 802 is a "burst signal" in which a plurality of signals are divided by a fixed time width (time slot: TS) on the time axis on the same line and the same wavelength transmission path. A burst signal is an optical signal that is intermittent on the time axis, and in TDM transmission, data is superimposed on this burst signal and transmitted. Between burst signals, there is a no-signal period (guard time: GT) in which the optical power is approximately 0.
　光ＴＤＭ伝送のデータ転送方式では、同じ回線上に接続される複数のノード (伝送装置)が互いに時間差で同一波長上にバースト信号を送信することで、信号同士の衝突を回避する。バースト信号同士が衝突せずに宛先の受信端に到着できる状態を同期状態と呼ぶ。 In the data transfer method of optical TDM transmission, multiple nodes (transmission equipment) connected on the same line transmit burst signals on the same wavelength at different times to avoid collisions between signals. A state in which burst signals can reach the destination receiving end without colliding with each other is called a synchronous state.
　光ＴＤＭ伝送では、バースト信号の送信ノード間でタイミングを合わせることで、信号同士の衝突の生じない同期状態をとる。そのためには、ノード間の信号の伝搬遅延時間を差し引いて、各ノードがバースト信号の送信・方路切り替えを行う必要がある。また、信号を伝搬する光ファイバは、温度変化によって光学距離が時間的に変動する。そのため、光ＴＤＭ伝送のための高精度な同期をとるためには、光学距離の時間的変動に起因した信号伝搬遅延時間のズレも考慮しつつ、各ノードが高精度にタイミングを合わせる必要がある。 In optical TDM transmission, by synchronizing the timing between nodes transmitting burst signals, a synchronized state is achieved in which collisions between signals do not occur. To do this, it is necessary for each node to transmit burst signals and switch routes by subtracting the propagation delay time of signals between nodes. Furthermore, the optical distance of an optical fiber through which signals are propagated changes over time due to temperature changes. Therefore, in order to achieve highly accurate synchronization for optical TDM transmission, it is necessary for each node to synchronize the timing with high precision while also taking into account the difference in signal propagation delay time caused by temporal fluctuations in optical distance. .
　信号の伝搬遅延、伝搬遅延変動を考慮して同期をとる既存技術として最も一般的なものに、現光アクセス網において普及しているＰＯＮ（Passive Optical Network）の光ＴＤＭ伝送方式がある。ＰＯＮでは、通信事業者のビルに置かれるＯＬＴ（Optical Line Terminal）と呼ばれるマスターノードと各ユーザ宅に置かれるＯＮＵ (Optical Network Unit) と呼ばれるノードが受動部品である光スプリッタと光ファイバからなる伝送路を介して接続された、ツリー構造を持つＰ２ＭＰ（Point to Multi-point）型光アクセスシステムの1形態である。ＯＬＴは、各ＯＮＵとの間のＲＴＴ (Round Trip Time)を予め測定して置き、各ＯＮＵからの信号が衝突しないタイミングを算出して各ＯＮＵに通知することでＯＮＵ間における同期をとり、その上で、ＯＬＴは、それぞれのＯＮＵに信号の送信タイミングを指示する。 The most common existing technology that takes into account signal propagation delay and propagation delay variation for synchronization is the optical TDM transmission system of PON (Passive Optical Network), which is popular in current optical access networks. In PON, a master node called OLT (Optical Line Terminal) placed in the building of the telecommunications carrier and a node called ONU (Optical Network Unit) placed in each user's home are used for transmission consisting of passive components such as optical splitters and optical fibers. This is a type of P2MP (Point to Multi-point) type optical access system that has a tree structure and is connected via a network. The OLT measures the RTT (Round Trip Time) between each ONU in advance, calculates the timing at which the signals from each ONU will not collide, and notifies each ONU of the timing to synchronize the ONUs. Above, the OLT instructs each ONU regarding the timing of signal transmission.
　図１５は、非特許文献１に記載されるＴＤＭ－ＰＯＮシステムの構成図である。
　光伝送システムは、ＯＬＴが各ＯＮＵと光ファイバで接続される。ＯＬＴからの光ファイバは、光スプリッタＳＰを介して、各ＯＮＵに分岐される。以下、ＯＬＴからＯＮＵへの信号の流れを「下り信号」とし、ＯＮＵからＯＬＴへの信号の流れを「上り信号」とする。 FIG. 15 is a configuration diagram of the TDM-PON system described in Non-Patent Document 1.
In the optical transmission system, an OLT is connected to each ONU through an optical fiber. Optical fibers from the OLT are branched to each ONU via an optical splitter SP. Hereinafter, the signal flow from the OLT to the ONU will be referred to as a "downstream signal," and the signal flow from the ONU to the OLT will be referred to as an "upstream signal."
　図１６は、図１５のＴＤＭ－ＰＯＮシステムにおける信号の流れを示すシーケンス図である。
　ＯＬＴは、ＯＮＵにＲＴＴ測定用の下り連続信号を時刻ｔ０に送信する。宛先のＯＮＵは、ＯＬＴからの下り連続信号を受信したタイミングで時刻をｔ０に設定する（Ｓ１１）。ＯＮＵは、ＯＬＴによって指定された時刻ｔ１になると、ＲＴＴ測定用の上りバースト信号を送信する。ＯＬＴは、上りバースト信号を受信した時刻ｔ２を取得する（Ｓ１２）。これにより、ＯＬＴは、時刻ｔ０～ｔ２のタイムスタンプをもとに、ＯＮＵとの間のＲＴＴを算出する。
　ＯＬＴは、算出したＲＴＴをもとに、ＯＮＵにバースト光を用いたデータ信号の送信タイミングを送信する（Ｓ１３）。ＯＮＵは、通知されたタイミングをもとに、バースト光を用いてデータ信号を送信する（Ｓ１４）。 FIG. 16 is a sequence diagram showing the signal flow in the TDM-PON system of FIG. 15.
The OLT transmits a downlink continuous signal for RTT measurement to the ONU at time t0. The destination ONU sets the time to t0 at the timing of receiving the downlink continuous signal from the OLT (S11). The ONU transmits an uplink burst signal for RTT measurement at time t1 specified by the OLT. The OLT obtains time t2 at which the uplink burst signal is received (S12). Thereby, the OLT calculates the RTT with the ONU based on the timestamps from time t0 to t2.
Based on the calculated RTT, the OLT transmits the transmission timing of a data signal using burst light to the ONU (S13). The ONU transmits a data signal using burst light based on the notified timing (S14).
　図１７は、非特許文献１、２に記載される１対Ｎ光接続（Ｐ２ＭＰ光接続）なネットワークにおけるＴＤＭ－ＰＯＮシステムの構成図である。
　この構成図では、１台のＯＬＴと、Ｎ台（ここではＮ＝３）のＯＮＵとが接続される。ＯＬＴから各ＯＮＵへの下り連続信号Ｐ１１と、各ＯＮＵからＯＬＴへの上りバースト信号Ｐ１２が多重された信号Ｐ１３とがノード間を伝搬する。
　下り信号Ｐ１１は、例えば、図１６のＲＴＴ測定で使用するＳｙｎｃ（同期）信号（Ｓ１１）およびタイミング通知信号（Ｓ１３）である。上り信号Ｐ１２は、例えば、図１６のＳｙｎｃ信号（Ｓ１２）および他ＯＮＵあてのデータ信号（Ｓ１４）である。ＯＬＴは、各ＯＮＵがデータ信号（Ｓ１４）を送受信する度に、ＲＴＴの測定を行うことで、数１０-数１００[ns]程度の同期精度を達成している。 FIG. 17 is a configuration diagram of a TDM-PON system in a 1-to-N optical connection (P2MP optical connection) network described in Non-Patent Documents 1 and 2.
In this configuration diagram, one OLT and N (N=3 in this case) ONUs are connected. A continuous down signal P11 from the OLT to each ONU and a signal P13 in which the up burst signal P12 from each ONU to the OLT is multiplexed propagate between nodes.
The downlink signal P11 is, for example, a Sync signal (S11) and a timing notification signal (S13) used in the RTT measurement in FIG. 16. The upstream signal P12 is, for example, the Sync signal (S12) in FIG. 16 and the data signal (S14) addressed to another ONU. The OLT achieves synchronization accuracy of several tens to hundreds of nanoseconds by measuring RTT every time each ONU transmits and receives a data signal (S14).
　前記した図１７の１対Ｎ光接続（P2MP光接続）なネットワークを、Ｎ対Ｍ光接続（MP2MP光接続）なネットワークに拡張することを検討する。
　図１８は、Ｎ対Ｍ光接続なネットワークにおけるＴＤＭ－ＰＯＮシステムの構成図である。
　この構成図では、図面左側に配置されるＮ台（ここではＮ＝３）のＯＮＵの集合をMetro網の送信側とし、図面右側に配置されるＭ台（ここではＭ＝３）のＯＮＵの集合をMetro網の受信側とする。そして、その左右のMetro網をCore網で接続して、光直結とする。なお、送信側のＯＮＵとは、データ信号Ｐ１２の送信元となるＯＮＵ相当を示す。受信側のＯＮＵとは、データ信号Ｐ１３を受信するＯＮＵ相当を示す。 Consider expanding the 1-to-N optical connection (P2MP optical connection) network shown in FIG. 17 described above to an N-to-M optical connection (MP2MP optical connection) network.
FIG. 18 is a configuration diagram of a TDM-PON system in an N-to-M optical connection network.
In this configuration diagram, a set of N ONUs (here N = 3) placed on the left side of the drawing is the transmission side of the Metro network, and a set of M ONUs (here M = 3) placed on the right side of the drawing is the transmission side of the Metro network. Let the set be the receiving side of the Metro network. Then, connect the left and right Metro networks with the Core network to create a direct optical connection. Note that the transmitting side ONU corresponds to the ONU that is the transmitting source of the data signal P12. The receiving side ONU refers to an ONU that receives the data signal P13.
　なお、受信側のＯＮＵから送信側のＯＮＵに向けて送信（返信）されるデータ信号Ｐ１４も存在する。この受信側のＯＮＵから送信側のＯＮＵに向かうデータ信号Ｐ１４は、送信側のＯＮＵに向かう図１７の下り信号Ｐ１１と同じ向きである。既存のＰＯＮシステムでは、ＯＬＴにおける電気処理によってデータ信号にＳｙｎｃ信号を付与し、連続信号として各ＯＮＵに下り信号を送信するが、ノード間で電気終端を含まないＮ対Ｍ光接続なネットワークでは、ＯＬＴ相当においてデータ信号Ｐ１４にＳｙｎｃ信号を付与して連続信号として送信することができない。そのため、既存のＴＤＭ-ＰＯＮシステムで使用される従来の同期手法は、Ｎ対Ｍ光接続なネットワークにそのまま適用することができない。 Note that there is also a data signal P14 that is transmitted (replyed) from the receiving ONU to the transmitting ONU. The data signal P14 heading from the receiving side ONU to the sending side ONU is in the same direction as the downlink signal P11 in FIG. 17 heading towards the sending side ONU. In existing PON systems, a Sync signal is added to the data signal through electrical processing in the OLT, and the downlink signal is transmitted to each ONU as a continuous signal, but in an N-to-M optical connection network that does not include electrical termination between nodes, In an OLT equivalent, it is not possible to add a Sync signal to the data signal P14 and transmit it as a continuous signal. Therefore, the conventional synchronization method used in the existing TDM-PON system cannot be directly applied to an N-to-M optical connection network.
　図２０は、ＴＤＭ伝送の送信周期の説明図である。
　タイムスロットは、周期Ｔごとに区切られて各ＯＮＵに割り当てられる。この周期のことをＴＤＭフレーム長と呼ぶ。例えば、第１のＯＮＵは、１回目の周期Ｔでは１つのデータ信号を送信でき、次の周期Ｔでは別のデータ信号を送信できる。タイムスロット間に設けられたＧＴは、信号のズレ（同期誤差）を吸収する役割を果たす。 FIG. 20 is an explanatory diagram of the transmission cycle of TDM transmission.
Time slots are divided into periods T and assigned to each ONU. This period is called the TDM frame length. For example, a first ONU may transmit one data signal in a first period T and another data signal in a next period T. The GT provided between time slots plays the role of absorbing signal deviations (synchronization errors).
　図２１は、左から右へ流れるバースト信号の信号衝突の説明図である。
　符号８１１では、第１のデータ信号８１１Ａ、第２のデータ信号８１１Ｂ、第３のデータ信号８１１Ｃが、順に光ファイバに重畳される。ここで、ＯＮＵ間の同期誤差が大きいことにより、第１のデータ信号８１１Ａのタイムスロットと、第２のデータ信号８１１Ｂのタイムスロットとが一部重複してしまうことで信号衝突が発生してしまう。
　符号８１２では、第１のデータ信号８１２Ａ、第２のデータ信号８１２Ｂ、第３のデータ信号８１２Ｃが、順に光ファイバに重畳される。ここで、ＯＮＵ間の同期誤差が小さいので、各データ信号のタイムスロットが重複せずに正しく重畳できる。 FIG. 21 is an explanatory diagram of signal collision of burst signals flowing from left to right.
At 811, a first data signal 811A, a second data signal 811B, and a third data signal 811C are sequentially superimposed on the optical fiber. Here, due to a large synchronization error between ONUs, the time slot of the first data signal 811A and the time slot of the second data signal 811B partially overlap, resulting in signal collision. .
At 812, a first data signal 812A, a second data signal 812B, and a third data signal 812C are sequentially superimposed onto the optical fiber. Here, since the synchronization error between ONUs is small, the time slots of each data signal can be correctly superimposed without overlapping.
　つまり、符号８１２に示すようにＯＮＵ間の同期誤差をＧＴで補償できるオーダに抑える必要がある。
　一方で、ＲＴＴ測定ベースの既存の同期手法は、パケット処理に伴う信号処理の遅延揺らぎによる同期誤差が少なからず生じるため、同期の飛躍的な高精度化が困難である。また、ネットワーク内で電気処理を行わない以上、ＯＬＴからの下り信号に別波長が必要になる点や、ＯＮＵ数の増加とともに、複数台のＯＮＵそれぞれと同期するＯＬＴに負荷が集中してしまう点、高精度な同期のためには波長毎のＲＴＴ測定が必要となる点などが課題となる。Ｎ対Ｍ光接続なネットワークにおいて光ＴＤＭ伝送のための高精度な同期を実現するためには、ＲＴＴ測定をベースとしない高精度同期を実現するタイミング調整手法の確立が求められる。 In other words, as shown by reference numeral 812, it is necessary to suppress the synchronization error between ONUs to an order that can be compensated for by the GT.
On the other hand, with existing synchronization methods based on RTT measurements, it is difficult to dramatically improve the precision of synchronization because a considerable amount of synchronization error occurs due to delay fluctuations in signal processing accompanying packet processing. In addition, since no electrical processing is performed within the network, a separate wavelength is required for the downlink signal from the OLT, and as the number of ONUs increases, the load will be concentrated on the OLT, which is synchronized with each of multiple ONUs. The problem is that RTT measurement for each wavelength is required for highly accurate synchronization. In order to achieve highly accurate synchronization for optical TDM transmission in an N-to-M optical connection network, it is necessary to establish a timing adjustment method that achieves highly accurate synchronization that is not based on RTT measurement.
　そこで、本発明は、Ｎ対Ｍ光接続な光ＴＤＭ伝送ネットワークにおいて、各ノードに対するＲＴＴを測定せずとも、多重時におけるデータ信号同士の衝突を回避することを主な課題とする。 Therefore, the main objective of the present invention is to avoid collisions between data signals during multiplexing without measuring the RTT for each node in an optical TDM transmission network with N-to-M optical connections.
　前記課題を解決するために、本発明の光ＴＤＭ伝送装置は、以下の特徴を有する。
　本発明は、複数の光ＴＤＭ伝送装置が、ノード間のタイムスロットを同期した状態でデータ信号の送信を行う光ＴＤＭ伝送システムにおいて、
　各前記光ＴＤＭ伝送装置が、
　前記データ信号とは物理的性質の異なるタイミング信号を受信し、受信した前記タイミング信号の受信時刻および受信周期を、前記タイミング信号の受信タイミングとして記憶し、
　記憶された前記受信タイミングを基準にして把握したタイムスロットに、自身から送信される前記データ信号を重畳するように制御することを特徴とする。 In order to solve the above problems, the optical TDM transmission device of the present invention has the following features.
The present invention provides an optical TDM transmission system in which a plurality of optical TDM transmission devices transmit data signals while synchronizing time slots between nodes.
Each of the optical TDM transmission devices includes:
receiving a timing signal having different physical properties from the data signal, storing the reception time and reception period of the received timing signal as the reception timing of the timing signal;
The data signal transmitted from itself is controlled to be superimposed on a time slot grasped based on the stored reception timing.
　本発明によれば、Ｎ対Ｍ光接続なネットワークにおいて各ノードに対してＲＴＴを測定せずとも、多重時におけるデータ信号同士の衝突を回避することができる。 According to the present invention, collisions between data signals during multiplexing can be avoided without measuring RTT for each node in an N-to-M optical connection network.
本実施形態に関するＮ対Ｍ光接続なネットワークにおける光ＴＤＭ伝送システムの構成図である。FIG. 1 is a configuration diagram of an optical TDM transmission system in an N-to-M optical connection network according to the present embodiment. 本実施形態に関する図１のＮ対Ｍ光接続なネットワークを、リングトポロジを持つネットワークに適用した場合の構成図である。FIG. 2 is a configuration diagram when the N-to-M optical connection network of FIG. 1 according to the present embodiment is applied to a network having a ring topology. 本実施形態に関するＴ送信機の説明図である。It is an explanatory diagram of a T transmitter concerning this embodiment. 本実施形態に関する図３のバースト信号を構成するタイムスロットの説明図である。FIG. 4 is an explanatory diagram of time slots forming the burst signal of FIG. 3 according to the present embodiment. 本実施形態に関するＴ送信機の構成図である。It is a block diagram of the T transmitter regarding this embodiment. 本実施形態に関するタイミング信号の抽出方法を示す時系列のタイムスロット図である。FIG. 3 is a time-series time slot diagram showing a timing signal extraction method according to the present embodiment. 本実施形態に関する図６の一部を拡大したタイムスロット図である。FIG. 7 is a time slot diagram in which a part of FIG. 6 is enlarged according to the present embodiment. 本実施形態に関するノードの構成図である。FIG. 2 is a configuration diagram of a node related to this embodiment. 本実施形態に関する図８のノードの動作を示すシーケンス図である。9 is a sequence diagram showing the operation of the node in FIG. 8 according to the present embodiment. FIG. 本実施形態に関するタイミング信号の抽出方法を示す時系列のタイムスロット図である。FIG. 3 is a time-series time slot diagram showing a timing signal extraction method according to the present embodiment. 本実施形態に関する図１０の一部を拡大したタイムスロット図である。FIG. 11 is a time slot diagram in which a part of FIG. 10 is enlarged according to the present embodiment. 本実施形態に関するノードの構成図である。FIG. 2 is a configuration diagram of a node related to this embodiment. 本実施形態に関する図１２のノードの動作を示すシーケンス図である。FIG. 13 is a sequence diagram showing the operation of the node in FIG. 12 according to the present embodiment. 本実施形態に関する光ＴＤＭ伝送装置（図８のノードおよび図１２のノード）のハードウェア構成図である。13 is a hardware configuration diagram of an optical TDM transmission device (the node in FIG. 8 and the node in FIG. 12) according to the present embodiment. FIG. 非特許文献１に記載されるＴＤＭ－ＰＯＮシステムの構成図である。1 is a configuration diagram of a TDM-PON system described in Non-Patent Document 1. FIG. 図１５のＴＤＭ－ＰＯＮシステムにおける信号の流れを示すシーケンス図である。16 is a sequence diagram showing the flow of signals in the TDM-PON system of FIG. 15. FIG. 非特許文献１、２に記載される１対Ｎ光接続（Ｐ２ＭＰ光接続）なネットワークにおけるＴＤＭ－ＰＯＮシステムの構成図である。1 is a configuration diagram of a TDM-PON system in a 1-to-N optical connection (P2MP optical connection) network described in Non-Patent Documents 1 and 2. FIG. Ｎ対Ｍ光接続なネットワークにおけるＴＤＭ－ＰＯＮシステムの構成図である。FIG. 1 is a configuration diagram of a TDM-PON system in an N-to-M optical connection network. 光ＴＤＭ伝送で使用する信号と通常の伝送網で使用される信号を示した説明図である。FIG. 2 is an explanatory diagram showing signals used in optical TDM transmission and signals used in a normal transmission network. ＴＤＭ伝送の送信周期の説明図である。FIG. 2 is an explanatory diagram of a transmission cycle of TDM transmission. 左から右へ流れるバースト信号の信号衝突の説明図である。FIG. 3 is an explanatory diagram of signal collision of burst signals flowing from left to right.
　以下、本発明の一実施形態について、図面を参照して詳細に説明する。 Hereinafter, one embodiment of the present invention will be described in detail with reference to the drawings.
　図１は、Ｎ対Ｍ光接続なネットワークにおける光ＴＤＭ伝送システムの構成図である。このＴＤＭ伝送システムは、複数のノードが、ノード間のタイムスロットを同期した状態でデータ信号の送信を行う光ＴＤＭシステムの一例である。
　図１のＴＤＭ伝送システムは、図１８の送信側の各ＯＮＵとの間でＲＴＴを計測する（2-wayの同期処理）ＯＬＴの代わりに、Ｔ（Timing）送信機３０を備える。Ｔ送信機３０は、送信側の各ノードに対してタイミング信号Ｐ１５をデータ信号と同一波長上の１タイムスロットを用いて送信する。送信側の各ノードは、タイミング信号Ｐ１５を受信し、受信したタイミング信号Ｐ１５の受信時刻および受信周期を、受信タイミングとして自身に記憶する。各ノードがタイミング信号の受信タイミングを把握することで、データ信号を重畳するタイムスロットを高精度に把握することができる（1-wayの同期処理）。 FIG. 1 is a configuration diagram of an optical TDM transmission system in an N-to-M optical connection network. This TDM transmission system is an example of an optical TDM system in which a plurality of nodes transmit data signals while synchronizing time slots between the nodes.
The TDM transmission system in FIG. 1 includes a T (Timing) transmitter 30 instead of the OLT that measures RTT with each ONU on the transmitting side (2-way synchronization processing) in FIG. 18. The T transmitter 30 transmits a timing signal P15 to each node on the transmitting side using one time slot on the same wavelength as the data signal. Each node on the transmitting side receives the timing signal P15 and stores therein the reception time and reception period of the received timing signal P15 as the reception timing. By understanding the reception timing of the timing signal by each node, it is possible to accurately determine the time slot in which the data signal is to be superimposed (1-way synchronization processing).
　Ｔ送信機３０はタイミング信号Ｐ１５を送信し、各ノードは受信したタイミング信号Ｐ１５を、受信タイミングとして記憶する。タイミング信号Ｐ１５を、複数のノードがデータ信号を送信する波長毎に受信することにより、間接的に波長毎の伝搬遅延時間を補正したノード間のタイムスロット同期状態が達成される。 The T transmitter 30 transmits a timing signal P15, and each node stores the received timing signal P15 as a reception timing. By receiving the timing signal P15 for each wavelength at which a plurality of nodes transmit data signals, a time slot synchronization state between the nodes is achieved in which the propagation delay time for each wavelength is indirectly corrected.
　ここで、Ｔ送信機３０は、タイミング信号Ｐ１５とデータ信号Ｐ１２とを各ノードに区別させるために、データ信号Ｐ１２とは、強度やタイムスロット幅等の物理的性質の異なるタイミング信号Ｐ１５を送信する。物理的性質が異なるタイミング信号Ｐ１５とは、以下に例示する信号である。
　・光のパワー（強度）がデータ信号Ｐ１２とは異なるタイミング信号Ｐ１５
　・タイムスロット幅（ＴＳ幅）がデータ信号Ｐ１２とは異なるタイミング信号Ｐ１５ Here, in order to make each node distinguish between the timing signal P15 and the data signal P12, the T transmitter 30 transmits the timing signal P15 which has different physical properties such as intensity and time slot width from the data signal P12. . The timing signal P15 having different physical properties is a signal exemplified below.
・Timing signal P15 whose optical power (intensity) is different from that of data signal P12
・Timing signal P15 whose time slot width (TS width) is different from that of data signal P12
　そして、各ノードは、データ信号Ｐ１２とは物理的性質の異なるタイミング信号Ｐ１５を受信し、受信したタイミング信号Ｐ１５の受信時刻および受信周期を、タイミング信号Ｐ１５の受信タイミングとして記憶する。
　さらに、各ノードは、記憶された受信タイミングを基準にして把握したタイムスロットに、自身から送信されるデータ信号Ｐ１２を重畳するように制御する。
　また、各ノードは、受信タイミングが記憶された後においても、各ノードに対して送信されるタイミング信号Ｐ１５を受信し、受信したタイミング信号Ｐ１５をもとに、記憶した受信タイミングを補正する。 Each node receives a timing signal P15 having different physical properties from the data signal P12, and stores the reception time and reception period of the received timing signal P15 as the reception timing of the timing signal P15.
Further, each node controls the data signal P12 transmitted from itself to be superimposed on the time slot determined based on the stored reception timing.
Further, even after the reception timing is stored, each node receives the timing signal P15 transmitted to each node, and corrects the stored reception timing based on the received timing signal P15.
　これにより、各ノードは、物理的性質の異なる信号をタイミング信号Ｐ１５とみなして抽出できる。このことは、各ノードが、偶発的なタイミング信号Ｐ１５のズレを物理レイヤで把握し、そのズレを補正できることを意味する。よって、信号の送受信を行う光パス上に重畳されたタイミング信号Ｐ１５を、物理レイヤで各ノードに検出させることで、何かしらの原因でノード間のタイムスロットの同期状態が途切れたとしても，再度タイミング信号Ｐ１５を受信するのみで，高精度な同期状態を改めてとりなおすことが可能である。
　また、タイミング信号Ｐ１５とデータ信号Ｐ１２とが同じ波長において重畳されたバースト信号Ｐ１３が、光パス上に流れる。受信側の各ノードは、受信したバースト信号Ｐ１３の物理的性質を参照して、タイミング信号を破棄しつつ、所望のデータ信号Ｐ１３を抽出できる。 Thereby, each node can extract a signal having different physical properties by regarding it as the timing signal P15. This means that each node can grasp the accidental deviation of the timing signal P15 at the physical layer and correct the deviation. Therefore, by having each node detect the timing signal P15 superimposed on the optical path for transmitting and receiving signals at the physical layer, even if the synchronization state of time slots between nodes is interrupted for some reason, the timing signal P15 superimposed on the optical path for transmitting and receiving signals can be detected again. By simply receiving the signal P15, it is possible to re-establish a highly accurate synchronization state.
Furthermore, a burst signal P13 in which the timing signal P15 and the data signal P12 are superimposed at the same wavelength flows on the optical path. Each node on the receiving side can refer to the physical properties of the received burst signal P13 and extract the desired data signal P13 while discarding the timing signal.
　図２は、図１のＮ対Ｍ光接続なネットワークを、リングトポロジを持つネットワークに適用した場合の構成図である。
　図１では、３台のノードが送信側として図面左側に配置され、３台のノードが受信側として図面右側に配置されていた。
　図２では、４台のノードが送信側として図面左側に配置され、５台のノードが受信側として図面右側に配置される。
　Ｔ送信機３０は、送信側の４台のノードに対して、タイミング信号Ｔを送信する。つまり、タイミング信号Ｔの始点は、図１でも図２でもＴ送信機３０である。送信側の４台のノードは、タイミング信号Ｔにデータ信号Ｄを重畳させる。受信側の５台のノードは、タイミング信号Ｔとデータ信号Ｄとを受信する。 FIG. 2 is a configuration diagram when the N-to-M optical connection network of FIG. 1 is applied to a network having a ring topology.
In FIG. 1, three nodes are placed on the left side of the drawing as the transmitting side, and three nodes are placed on the right side of the drawing as the receiving side.
In FIG. 2, four nodes are placed on the left side of the drawing as transmitters, and five nodes are placed on the right side of the drawing as receivers.
The T transmitter 30 transmits a timing signal T to the four nodes on the transmitting side. That is, the starting point of the timing signal T is the T transmitter 30 in both FIG. 1 and FIG. The four nodes on the transmitting side superimpose the data signal D on the timing signal T. The five nodes on the receiving side receive the timing signal T and the data signal D.
　図３は、Ｔ送信機３０の説明図である。
　Ｔ送信機３０は、ノードＡに対して、タイミング信号Ｐ１５を送信する。ノードＡは、タイミング信号Ｐ１５を受信するとともに、ノードＡから送信されるデータ信号を、タイミング信号Ｐ１５と同一波長を用いて送信する。
　ノードＢは、タイミング信号Ｐ１５とノードＡから送信されるデータ信号の内、タイミング信号Ｐ１５のみを抽出するとともに、ノードＢから送信されるデータ信号を、タイミング信号Ｐ１５と同一波長を用いて送信する。
　ノードＣは、タイミング信号Ｐ１５とノードＡ、Ｂから送信されるデータ信号の内、タイミング信号Ｐ１５のみを抽出するとともに、ノードＣから送信されるデータ信号を、タイミング信号Ｐ１５と同一波長を用いて送信する。
　これにより、タイミング信号Ｐ１５と、各ノードＡ、Ｂ、Ｃから送信されるデータ信号Ｐ１２とが、信号Ｐ１３として多重される。 FIG. 3 is an explanatory diagram of the T transmitter 30.
T transmitter 30 transmits timing signal P15 to node A. Node A receives the timing signal P15 and transmits the data signal transmitted from node A using the same wavelength as the timing signal P15.
The node B extracts only the timing signal P15 from the timing signal P15 and the data signal transmitted from the node A, and transmits the data signal transmitted from the node B using the same wavelength as the timing signal P15.
Node C extracts only timing signal P15 from the timing signal P15 and the data signals transmitted from nodes A and B, and transmits the data signal transmitted from node C using the same wavelength as timing signal P15. do.
As a result, the timing signal P15 and the data signal P12 transmitted from each node A, B, and C are multiplexed as a signal P13.
　図４は、図３のバースト信号Ｐ１３を構成するタイムスロットの説明図である。
　符号１０１は、Ｔ送信機３０が最初にタイミング信号Ｔを送信した時点の波長λ１のタイムスロットである。各ノードはタイミング信号Ｔを受信する。符号１０３に示す信号別のパターンにより、周期的にタイミング信号Ｔが挿入されており、その他のタイムスロットは、空スロットである。
　符号１０２は、符号１０１の空スロットに対して、ある１ノードがデータ信号をバースト信号（バースト光）として、送信（重畳）した時点の波長λ１のタイムスロットである。 FIG. 4 is an explanatory diagram of time slots forming the burst signal P13 of FIG. 3.
Reference numeral 101 is a time slot of wavelength λ1 at the time when the T transmitter 30 first transmits the timing signal T. Each node receives a timing signal T. A timing signal T is periodically inserted according to a signal-specific pattern indicated by reference numeral 103, and the other time slots are empty slots.
Reference numeral 102 is a time slot of wavelength λ1 at the time when a certain node transmits (superimposes) a data signal as a burst signal (burst light) to the empty slot 101.
　図５は、Ｔ送信機３０の構成図である。
　Ｔ送信機３０は、クロック部３１と、カウンタ管理部３２と、制御部３３と、タイミング信号送信部３４とを有する。
　クロック部３１は、クロックをカウンタ管理部３２に供給する。カウンタ管理部３２は、クロック部３１からのクロックをもとに、タイミング信号を送信してから次のタイミング信号を送信するまでの時間を、カウンタ値としてカウントする。
　制御部３３は、カウンタ管理部３２から通知されるカウンタ値をもとに、タイミング信号を送信するようにタイミング信号送信部３４を制御する。タイミング信号送信部３４は、制御部３３の制御に従い、タイミング信号を送信する。 FIG. 5 is a configuration diagram of the T transmitter 30.
The T transmitter 30 includes a clock section 31, a counter management section 32, a control section 33, and a timing signal transmission section 34.
The clock section 31 supplies a clock to the counter management section 32. The counter management unit 32 counts the time from transmitting a timing signal until transmitting the next timing signal as a counter value based on the clock from the clock unit 31.
The control section 33 controls the timing signal transmission section 34 to transmit the timing signal based on the counter value notified from the counter management section 32. The timing signal transmitter 34 transmits a timing signal under the control of the controller 33.
　以下、図６～図９を参照して、データ信号とは異なる物理的性質の一例として、光のパワーが異なるタイミング信号の処理を説明する。パワーが異なるタイミング信号の処理の概要は、次の（処理１Ａ）～（処理３Ａ）の通りである。
　（処理１Ａ）準備期間として、Ｔ送信機３０は、データ信号とは異なるパワーのタイミング信号を各ノードに送信することで、タイミング信号のパワー閾値を各ノードに記憶させる。
　（処理２Ａ）運用期間として、Ｔ送信機３０は、準備期間と同じタイミング信号を各ノードに送信する。各ノードは、記憶したパワー閾値を手がかりに、受信した信号がデータ信号かタイミング信号かを区別できる。受信したタイミング信号の受信タイミングは、これから送信するデータ信号の基準（どのＴＳに重畳するか）に使用される。
　（処理３Ａ）運用期間として、各ノードは、受信したタイミング信号をもとに、（処理２Ａ）のデータ信号の基準（受信タイミング）を修正する。 Hereinafter, with reference to FIGS. 6 to 9, processing of timing signals having different optical powers will be described as an example of physical properties different from data signals. The outline of processing of timing signals having different powers is as follows (Processing 1A) to (Processing 3A).
(Process 1A) During the preparation period, the T transmitter 30 causes each node to store the power threshold of the timing signal by transmitting a timing signal with a power different from that of the data signal to each node.
(Process 2A) During the operation period, the T transmitter 30 transmits the same timing signal as the preparation period to each node. Each node can distinguish whether a received signal is a data signal or a timing signal using the stored power threshold as a clue. The reception timing of the received timing signal is used as a reference for the data signal to be transmitted (which TS to superimpose on).
(Process 3A) During the operation period, each node corrects the standard (reception timing) of the data signal in (Process 2A) based on the received timing signal.
　図６は、タイミング信号の抽出方法を示す時系列のタイムスロット図である。
　図７は、図６の一部を拡大したタイムスロット図である。各信号の塗りパターンは、図４の符号１０３と同じである。
　Ｔ送信機３０は、所定のタイミングＴ０ごとに、光のパワーがデータ信号よりも大きい（図示では上方向に長い）タイミング信号を送信する。
　各ノードは、同一波長上で受信した各信号のパワーと所定のパワー閾値とを比較し、所定のパワー閾値を上回る信号を新たなタイミング信号とみなし、所定のパワー閾値以下の信号をデータ信号とみなす。そして、各ノードは、新たなタイミング信号をもとに、データ信号を重畳する基準（受信タイミング）を設定する。 FIG. 6 is a time-series time slot diagram showing a timing signal extraction method.
FIG. 7 is a time slot diagram in which a part of FIG. 6 is enlarged. The coloring pattern of each signal is the same as the reference numeral 103 in FIG.
The T transmitter 30 transmits a timing signal whose optical power is larger than the data signal (longer in the upward direction in the figure) at every predetermined timing T0.
Each node compares the power of each signal received on the same wavelength with a predetermined power threshold, and considers a signal above the predetermined power threshold to be a new timing signal, and a signal below the predetermined power threshold to be a data signal. I reckon. Then, each node sets a reference (reception timing) for superimposing the data signal based on the new timing signal.
　そのため、各ノードは、データ信号を送受信する前の準備期間において、Ｔ送信機３０からタイミング信号だけを受信し、受信したタイミング信号のパワー（の平均値など）を、所定のパワー閾値として設定しておくことが望ましい。または、各ノードは、所定のパワー閾値を設定データとして直接、管理者などから入力を受け付けてもよい。この準備期間の閾値設定処理は、光のパワーの閾値だけでなく、ＴＳ幅の閾値などの他の物理的性質の閾値の設定にも適用できる。
　また、データ信号を送受信する運用期間において、各ノードは、所定のパワー閾値を上回る新たなタイミング信号を受信した場合、データ信号を重畳する基準を修正してもよい。 Therefore, each node receives only the timing signal from the T transmitter 30 during the preparation period before transmitting and receiving the data signal, and sets the power (such as the average value) of the received timing signal as a predetermined power threshold. It is desirable to keep it. Alternatively, each node may directly receive input from an administrator or the like using a predetermined power threshold as setting data. This preparation period threshold setting process can be applied not only to the optical power threshold but also to the setting of other physical property thresholds such as the TS width threshold.
Furthermore, during the operation period for transmitting and receiving data signals, each node may modify the criteria for superimposing data signals if it receives a new timing signal that exceeds a predetermined power threshold.
　図８は、ノード５０の構成図である。このノード５０は、例えば、図１の左側に配置される３台の送信側ノードであり、図2の左側に配置される４台の送信側ノードである。
　ノード５０は、バースト光受信部５１と、ＴＩＡ（trans impedance amplifier）５２と、電圧検出回路部５３と、制御部５４と、ＴＳ（Time Slot）制御部５５と、カウンタ管理部５６と、クロック部５７と、バースト光送信部５８を備える。
　バースト光受信部５１は、タイミング信号を含むバースト光（バースト信号）を受信する。
　ＴＩＡ５２は、バースト信号の電流値を電圧値に変換する。
　電圧検出回路部５３は、変換された電圧値の波形レベルをモニタリングし、所定のパワー閾値を上回った信号をタイミング信号として制御部５４に通知し、所定のパワー閾値以下の信号をデータ信号として制御部５４に通知する。 FIG. 8 is a configuration diagram of the node 50. These nodes 50 are, for example, three transmitting nodes arranged on the left side of FIG. 1, and four transmitting nodes arranged on the left side of FIG.
The node 50 includes a burst light receiving section 51, a TIA (trans impedance amplifier) 52, a voltage detection circuit section 53, a control section 54, a TS (Time Slot) control section 55, a counter management section 56, and a clock section. 57, and a burst light transmitter 58.
The burst light receiving section 51 receives burst light (burst signal) including a timing signal.
The TIA 52 converts the current value of the burst signal into a voltage value.
The voltage detection circuit section 53 monitors the waveform level of the converted voltage value, notifies the control section 54 of signals exceeding a predetermined power threshold as timing signals, and controls signals below the predetermined power threshold as data signals. Department 54.
　制御部５４は、準備期間のタイミング信号を受けて、そのタイミング信号から計算した所定のパワー閾値を電圧検出回路部５３に設定する。そして、制御部５４は、運用期間に通知されたタイミング信号より得られた受信タイミングを、ＴＳ制御部５５とカウンタ管理部５６とに通知する。さらに、制御部５４は、新たなタイミング信号を受け、前回までに記憶していた受信タイミングを修正してもよい。
　ＴＳ制御部５５は、制御部５４から通知された受信タイミングをもとに、他の信号と衝突しないように、自装置が送信する信号を重畳するタイムスロットを制御する。
　カウンタ管理部５６は、制御部５４およびＴＳ制御部５５にカウンタ値を通知する。カウンタ値は、図５で説明したように、タイミング信号を送信してから次のタイミング信号を送信するまでの時間を示す。
　クロック部５７は、クロックをカウンタ管理部５６に供給する。
　バースト光送信部５８は、ＴＳ制御部５５で指定されたＴＳに任意の信号を重畳してデータ信号を送信する。 The control unit 54 receives the timing signal of the preparation period and sets a predetermined power threshold calculated from the timing signal in the voltage detection circuit unit 53. Then, the control unit 54 notifies the TS control unit 55 and the counter management unit 56 of the reception timing obtained from the timing signal notified during the operation period. Furthermore, the control unit 54 may receive a new timing signal and correct the previously stored reception timing.
Based on the reception timing notified from the control unit 54, the TS control unit 55 controls the time slot in which the signal transmitted by its own device is superimposed so as to avoid collision with other signals.
The counter management section 56 notifies the control section 54 and the TS control section 55 of the counter value. As explained in FIG. 5, the counter value indicates the time from transmitting a timing signal to transmitting the next timing signal.
The clock unit 57 supplies a clock to the counter management unit 56.
The burst light transmitter 58 superimposes an arbitrary signal on the TS designated by the TS controller 55 and transmits a data signal.
　図９は、図８のノード５０の動作を示すシーケンス図である。
　準備期間において、バースト光受信部５１は、バースト光を受信して電気信号に変換（O/E変換：Optical/Electrical変換）する（Ｓ１１１）。
　ＴＩＡ５２は、電気信号の電流値を電圧値に変換する（Ｓ１２１）。電圧検出回路部５３は、電圧値の時間応答を制御部５４に通知する（Ｓ１３１）。
　制御部５４は、タイミング信号の電圧値を把握する（Ｓ１４１）。制御部５４は、閾値となる電圧値を決定し、電圧検出回路部５３に通知する（Ｓ１４２）。 FIG. 9 is a sequence diagram showing the operation of node 50 in FIG.
During the preparation period, the burst light receiving unit 51 receives burst light and converts it into an electrical signal (O/E conversion: Optical/Electrical conversion) (S111).
The TIA 52 converts the current value of the electrical signal into a voltage value (S121). The voltage detection circuit section 53 notifies the control section 54 of the time response of the voltage value (S131).
The control unit 54 grasps the voltage value of the timing signal (S141). The control unit 54 determines the voltage value to be the threshold value and notifies the voltage detection circuit unit 53 (S142).
　運用期間において、バースト光受信部５１は、バースト光を受信して電気信号に変換（O/E変換）する（Ｓ１１２）。
　ＴＩＡ５２は、電気信号の電流値を電圧値に変換する（Ｓ１２２）。
　電圧検出回路部５３は、閾値を超える電圧値の時間応答（タイミング信号）を制御部５４に通知する（Ｓ１３２）。
　制御部５４は、タイミング信号の受信タイミングをカウンタ管理部５６に通知する（Ｓ１４３）。
　クロック部５７は、クロックを供給する（Ｓ１６１）。カウンタ管理部５６は、カウンタを開始する（Ｓ１５１）。 During the operation period, the burst light receiving unit 51 receives burst light and converts it into an electrical signal (O/E conversion) (S112).
The TIA 52 converts the current value of the electrical signal into a voltage value (S122).
The voltage detection circuit section 53 notifies the control section 54 of the time response (timing signal) of the voltage value exceeding the threshold value (S132).
The control unit 54 notifies the counter management unit 56 of the reception timing of the timing signal (S143).
The clock section 57 supplies a clock (S161). The counter management unit 56 starts a counter (S151).
　制御部５４は、タイムスロットの基準（受信タイミング）をＴＳ制御部５５に通知する（Ｓ１４４）。
　カウンタ管理部５６は、タイミング信号を受信してから次のタイミング信号を受信するまでの時間を示すカウンタ値をＴＳ制御部５５に通知する（Ｓ１５２）。
　ＴＳ制御部５５は、Ｄａｔａ（データ）信号を重畳するＴＳ（タイムスロット）を決定する（Ｓ１７１）。
　バースト光送信部５８は、ＴＳ制御部５５で指定されたＴＳに任意の信号を重畳してデータ信号を送信する（Ｓ１８１）。 The control unit 54 notifies the TS control unit 55 of the time slot reference (reception timing) (S144).
The counter management unit 56 notifies the TS control unit 55 of a counter value indicating the time from receiving a timing signal to receiving the next timing signal (S152).
The TS control unit 55 determines a TS (time slot) on which a Data signal is to be superimposed (S171).
The burst light transmitter 58 superimposes an arbitrary signal on the TS designated by the TS controller 55 and transmits a data signal (S181).
　以上、図６～図９を参照して、データ信号とは異なる物理的性質の一例として、光のパワーが異なるタイミング信号の処理を説明した。
　以下、図１０～図１３を参照して、データ信号とは異なる物理的性質の一例として、ＴＳ幅が異なるタイミング信号の処理を説明する。ＴＳ幅が異なるタイミング信号の処理の概要は次の（処理１Ｂ）～（処理３Ｂ）の通りである。
　（処理１Ｂ）準備期間として、Ｔ送信機３０は、データ信号とは異なるＴＳ幅のタイミング信号を各ノードに送信することで、タイミング信号のＴＳ幅を各ノードに記憶させる。
　（処理２Ｂ）運用期間として、Ｔ送信機３０は、準備期間と同じタイミング信号を各ノードに送信する。各ノードは、記憶したＴＳ幅を手がかりに、受信した信号がデータ信号かタイミング信号かを区別できる。受信したタイミング信号の受信タイミングは、これから送信するデータ信号の基準（どのＴＳに重畳するか）に使用される。
　（処理３Ｂ）運用期間として、各ノードは、受信したタイミング信号をもとに、（処理２Ｂ）のデータ信号の基準（受信タイミング）を修正する。 The processing of timing signals with different optical powers has been described above with reference to FIGS. 6 to 9 as an example of physical properties different from data signals.
Hereinafter, as an example of physical properties different from data signals, processing of timing signals having different TS widths will be described with reference to FIGS. 10 to 13. The outline of processing of timing signals having different TS widths is as follows (Processing 1B) to (Processing 3B).
(Process 1B) During the preparation period, the T transmitter 30 causes each node to store the TS width of the timing signal by transmitting a timing signal with a TS width different from that of the data signal to each node.
(Process 2B) During the operation period, the T transmitter 30 transmits the same timing signal as the preparation period to each node. Each node can distinguish whether a received signal is a data signal or a timing signal using the stored TS width as a clue. The reception timing of the received timing signal is used as a reference for the data signal to be transmitted (which TS to superimpose on).
(Process 3B) During the operation period, each node corrects the standard (reception timing) of the data signal in (Process 2B) based on the received timing signal.
　図１０は、タイミング信号の抽出方法を示す時系列のタイムスロット図である。
　図１１は、図１０の一部を拡大したタイムスロット図である。各信号の塗りパターンは、図４の符号１０３と同じである。
　Ｔ送信機３０は、所定のタイミングＴ０ごとに、ＴＳ幅がデータ信号よりも狭い（図示では左右の時間軸方向に短い）タイミング信号を送信する。また、各ノードは、一定のガードタイム（ＧＴ）を空けて、データ信号を重畳する。
　各ノードは、同一波長上で受信した各信号のＴＳ幅と所定のＴＳ幅閾値とを比較し、所定のＴＳ幅閾値を下回る信号を新たなタイミング信号とみなし、所定のＴＳ幅閾値以上の信号をデータ信号とみなす。そして、各ノードは、新たなタイミング信号をもとに、データ信号を重畳する基準を設定する。 FIG. 10 is a time-series time slot diagram showing a timing signal extraction method.
FIG. 11 is a time slot diagram in which a part of FIG. 10 is enlarged. The coloring pattern of each signal is the same as the reference numeral 103 in FIG.
The T transmitter 30 transmits a timing signal whose TS width is narrower than the data signal (shorter in the left and right time axis directions in the figure) at every predetermined timing T0. Furthermore, each node superimposes data signals after a certain guard time (GT).
Each node compares the TS width of each signal received on the same wavelength with a predetermined TS width threshold, considers a signal that is less than the predetermined TS width threshold as a new timing signal, and treats a signal that is greater than or equal to the predetermined TS width threshold as a new timing signal. is regarded as a data signal. Then, each node sets a standard for superimposing data signals based on the new timing signal.
　図１２は、ノード５０Ｂの構成図である。
　このノード５０Ｂは、図８のノード５０と比較すると、電圧検出回路部５３がＴＳ幅検出回路部５３Ｂに置き換わる。
　ＴＳ幅検出回路部５３Ｂは、変換された電圧値のＴＳ幅をモニタリングし、所定のＴＳ幅（パルス幅）閾値を下回った信号をタイミング信号として制御部５４に通知し、所定のＴＳ幅閾値以上の信号をデータ信号として制御部５４に通知する。
　制御部５４は、準備期間のタイミング信号を受けて、そのタイミング信号から計算した所定のＴＳ幅閾値をＴＳ幅検出回路部５３Ｂに設定する。
　その他の各処理部の処理内容は、図８で説明した通りである。 FIG. 12 is a configuration diagram of the node 50B.
In this node 50B, when compared with the node 50 in FIG. 8, the voltage detection circuit section 53 is replaced with a TS width detection circuit section 53B.
The TS width detection circuit unit 53B monitors the TS width of the converted voltage value, notifies the control unit 54 of a signal that is less than a predetermined TS width (pulse width) threshold as a timing signal, and notifies the control unit 54 of a signal that is less than a predetermined TS width (pulse width) threshold. The control unit 54 is notified of the signal as a data signal.
The control unit 54 receives the timing signal of the preparation period and sets a predetermined TS width threshold calculated from the timing signal in the TS width detection circuit unit 53B.
The processing contents of each other processing unit are as described in FIG. 8.
　図１３は、図１２のノード５０Ｂの動作を示すシーケンス図である。
　準備期間において、バースト光受信部５１は、バースト光を受信して電気信号に変換（O/E変換：Optical/Electrical変換）する（Ｓ２１１）。
　ＴＩＡ５２は、電気信号の電流値を電圧値に変換する（Ｓ２２１）。クロック部５７は、クロックをＴＳ幅検出回路部５３Ｂに供給する（Ｓ２６１）。ＴＳ幅検出回路部５３Ｂは、電圧値の時間応答でＴＳ幅を測定し、その測定結果を制御部５４に通知する（Ｓ２３１）。
　制御部５４は、タイミング信号のＴＳ幅値を把握する（Ｓ２４１）。制御部５４は、トリガとなるＴＳ幅を決定し、ＴＳ幅検出回路部５３Ｂに通知する（Ｓ２４２）。 FIG. 13 is a sequence diagram showing the operation of node 50B in FIG. 12.
During the preparation period, the burst light receiving unit 51 receives burst light and converts it into an electrical signal (O/E conversion: Optical/Electrical conversion) (S211).
The TIA 52 converts the current value of the electrical signal into a voltage value (S221). The clock section 57 supplies a clock to the TS width detection circuit section 53B (S261). The TS width detection circuit unit 53B measures the TS width based on the time response of the voltage value, and notifies the control unit 54 of the measurement result (S231).
The control unit 54 grasps the TS width value of the timing signal (S241). The control unit 54 determines the TS width that is a trigger and notifies the TS width detection circuit unit 53B (S242).
　運用期間において、バースト光受信部５１は、バースト光を受信して電気信号に変換（O/E変換）する（Ｓ２１２）。
　ＴＩＡ５２は、電気信号の電流値を電圧値に変換する（Ｓ２２２）。
　ＴＳ幅検出回路部５３Ｂは、指定されたＴＳ幅以下の信号（タイミング信号）を抽出して、そのタイミング信号を制御部５４に通知する（Ｓ２３２）。
　制御部５４は、タイミング信号の受信時刻（受信タイミング）を把握し、その受信時刻をカウンタ管理部５６に通知する（Ｓ２４３）。
　クロック部５７は、カウンタ管理部５６にクロックを供給する（Ｓ２６２）。カウンタ管理部５６は、カウンタを開始する（Ｓ２５１）。 During the operation period, the burst light receiving unit 51 receives burst light and converts it into an electrical signal (O/E conversion) (S212).
The TIA 52 converts the current value of the electrical signal into a voltage value (S222).
The TS width detection circuit unit 53B extracts a signal (timing signal) that is less than or equal to the specified TS width, and notifies the control unit 54 of the timing signal (S232).
The control unit 54 grasps the reception time (reception timing) of the timing signal, and notifies the counter management unit 56 of the reception time (S243).
The clock section 57 supplies a clock to the counter management section 56 (S262). The counter management unit 56 starts a counter (S251).
　制御部５４は、受信タイミングをＴＳ制御部５５に通知する（Ｓ２４４）。
　カウンタ管理部５６は、タイミング信号を受信してから次のタイミング信号を受信するまでの時間を示すカウンタ値をＴＳ制御部５５に通知する（Ｓ２５２）。
　ＴＳ制御部５５は、Ｄａｔａ信号を重畳するＴＳ（タイムスロット）を決定する（Ｓ２７１）。
　バースト光送信部５８は、ＴＳ制御部５５で指定されたＴＳに任意の信号を重畳してデータ信号を送信する（Ｓ２８１）。 The control unit 54 notifies the TS control unit 55 of the reception timing (S244).
The counter management unit 56 notifies the TS control unit 55 of a counter value indicating the time from receiving a timing signal to receiving the next timing signal (S252).
The TS control unit 55 determines the TS (time slot) on which the Data signal is to be superimposed (S271).
The burst light transmitter 58 superimposes an arbitrary signal on the TS specified by the TS controller 55 and transmits a data signal (S281).
　図１４は、光ＴＤＭ伝送装置（図８のノード５０および図１２のノード５０Ｂ）のハードウェア構成図である。
　光ＴＤＭ伝送装置は、ＣＰＵ９０１と、ＲＡＭ９０２と、ＲＯＭ９０３と、ＨＤＤ９０４と、通信Ｉ／Ｆ９０５と、入出力Ｉ／Ｆ９０６と、メディアＩ／Ｆ９０７とを有するコンピュータ９００として構成される。図５のＴ送信機３０も同様にコンピュータ９００として構成される。
　通信Ｉ／Ｆ９０５は、外部の通信装置９１５と接続される。入出力Ｉ／Ｆ９０６は、入出力装置９１６と接続される。メディアＩ／Ｆ９０７は、記録媒体９１７からデータを読み書きする。さらに、ＣＰＵ９０１は、ＲＡＭ９０２に読み込んだプログラム（アプリケーションや、その略のアプリとも呼ばれる）を実行することにより、各部を制御する。そして、このプログラムは、通信回線を介して配布したり、ＣＤ－ＲＯＭ等の記録媒体９１７に記録して配布したりすることも可能である。 FIG. 14 is a hardware configuration diagram of an optical TDM transmission device (node 50 in FIG. 8 and node 50B in FIG. 12).
The optical TDM transmission device is configured as a computer 900 having a CPU 901, a RAM 902, a ROM 903, an HDD 904, a communication I/F 905, an input/output I/F 906, and a media I/F 907. The T transmitter 30 in FIG. 5 is similarly configured as a computer 900.
Communication I/F 905 is connected to external communication device 915. The input/output I/F 906 is connected to the input/output device 916. The media I/F 907 reads and writes data from the recording medium 917. Further, the CPU 901 controls each unit by executing a program (also called an application or an abbreviated application) read into the RAM 902 . This program can also be distributed via a communication line or recorded on a recording medium 917 such as a CD-ROM.
［効果］
　本発明は、複数のノード５０が、ノード間のタイムスロットを同期した状態でデータ信号の送信を行う光ＴＤＭ伝送システムにおいて、
　各ノード５０が、
　データ信号とは物理的性質の異なるタイミング信号を受信し、受信したタイミング信号の受信時刻および受信周期を、タイミング信号の受信タイミングとして記憶し、
　記憶された受信タイミングを基準にして把握したタイムスロットに、自身から送信されるデータ信号を重畳するように制御することを特徴とする。 [effect]
The present invention provides an optical TDM transmission system in which a plurality of nodes 50 transmit data signals while synchronizing time slots between the nodes.
Each node 50 is
Receive a timing signal that has physical properties different from the data signal, and store the reception time and reception period of the received timing signal as the reception timing of the timing signal,
It is characterized by controlling the data signal transmitted from itself to be superimposed on the time slot grasped based on the stored reception timing.
　これにより、各ノード５０は、受信した信号の物理的性質を計測することで、データ信号かタイミング信号かを判別できる。よって、送信側の各ノードは、受信したタイミング信号の周期と受信時刻とを、受信タイミングとして自身に記憶することで、他ノードとの間で同期する（1-wayの同期処理）。
　そのため、Ｎ対Ｍ光接続なネットワークにおいて、個別のノードに対してＲＴＴを測定せずとも、多重時における信号同士の衝突を回避することができる。 Thereby, each node 50 can determine whether the received signal is a data signal or a timing signal by measuring the physical properties of the received signal. Therefore, each node on the transmitting side synchronizes with other nodes by storing the cycle and reception time of the received timing signal as reception timing in itself (1-way synchronization process).
Therefore, in a network with N-to-M optical connections, collisions between signals during multiplexing can be avoided without measuring RTT for each individual node.
　本発明は、各ノード５０が、データ信号とは物理的性質の異なるタイミング信号として、光のパワーがデータ信号とは異なるタイミング信号を受信することを特徴とする。 The present invention is characterized in that each node 50 receives a timing signal whose physical properties are different from that of the data signal, and whose optical power is different from that of the data signal.
　これにより、各ノード５０は、タイミング信号の信号内容を参照することなく、物理レイヤのパワーを測定することで、タイミング信号か否かを高速に判別できる。 Thereby, each node 50 can quickly determine whether a timing signal is a timing signal or not by measuring the power of the physical layer without referring to the signal content of the timing signal.
　本発明は、各ノード５０が、データ信号とは物理的性質の異なるタイミング信号として、タイムスロット幅がデータ信号とは異なるタイミング信号を受信することを特徴とする。 The present invention is characterized in that each node 50 receives a timing signal having a different time slot width from that of the data signal, as a timing signal whose physical properties are different from that of the data signal.
　これにより、各ノード５０は、タイミング信号の信号内容を参照することなく、物理レイヤのタイムスロット幅を測定することで、タイミング信号か否かを高速に判別できる。 As a result, each node 50 can quickly determine whether a timing signal is a timing signal or not by measuring the time slot width of the physical layer without referring to the signal content of the timing signal.
　本発明は、各ノード５０が、受信タイミングが記憶された後においても、各ノード５０に対して送信されるタイミング信号を受信し、受信したタイミング信号をもとに、記憶した受信タイミングを補正することを特徴とする。 In the present invention, each node 50 receives a timing signal transmitted to each node 50 even after the reception timing is stored, and corrects the stored reception timing based on the received timing signal. It is characterized by
　これにより、偶発的なタイミング信号のズレに対しても、タイミング信号の自律的な抽出により、高精度なノード間のタイムスロット同期状態を保つことができる。 As a result, even when there is an accidental deviation in the timing signal, highly accurate time slot synchronization between nodes can be maintained by autonomously extracting the timing signal.
　３０　　Ｔ送信機
　３１　　クロック部
　３２　　カウンタ管理部
　３３　　制御部
　３４　　タイミング信号送信部
　５０、５０Ｂ　ノード（光ＴＤＭ伝送装置）
　５１　　バースト光受信部
　５２　　ＴＩＡ
　５３　　電圧検出回路部
　５３Ｂ　ＴＳ幅検出回路部
　５４　　制御部
　５５　　ＴＳ制御部
　５６　　カウンタ管理部
　５７　　クロック部
　５８　　バースト光送信部 30 T transmitter 31 clock section 32 counter management section 33 control section 34 timing signal transmission section 50, 50B node (optical TDM transmission device)
51 Burst light receiver 52 TIA
53 Voltage detection circuit section 53B TS width detection circuit section 54 Control section 55 TS control section 56 Counter management section 57 Clock section 58 Burst light transmission section

Claims (6)

  1. 　複数の光ＴＤＭ伝送装置が、ノード間のタイムスロットを同期した状態でデータ信号の送信を行う光ＴＤＭ伝送システムにおいて、
    　各前記光ＴＤＭ伝送装置は、
    　前記データ信号とは物理的性質の異なるタイミング信号を受信し、受信した前記タイミング信号の受信時刻および受信周期を、前記タイミング信号の受信タイミングとして記憶し、
    　記憶された前記受信タイミングを基準にして把握したタイムスロットに、自身から送信される前記データ信号を重畳するように制御することを特徴とする
    　光ＴＤＭ伝送装置。     In an optical TDM transmission system in which a plurality of optical TDM transmission devices transmit data signals while synchronizing time slots between nodes,
    Each of the optical TDM transmission devices includes:
    receiving a timing signal having different physical properties from the data signal, storing the reception time and reception period of the received timing signal as the reception timing of the timing signal;
    An optical TDM transmission apparatus, characterized in that the optical TDM transmission apparatus controls the data signal transmitted from itself to be superimposed on a time slot determined based on the stored reception timing.
  2. 　各前記光ＴＤＭ伝送装置は、前記データ信号とは前記物理的性質の異なる前記タイミング信号として、光のパワーが前記データ信号とは異なる前記タイミング信号を受信することを特徴とする
    　請求項１に記載の光ＴＤＭ伝送装置。     According to claim 1, each of the optical TDM transmission devices receives the timing signal having different optical power from the data signal, as the timing signal having the physical properties different from the data signal. optical TDM transmission equipment.
  3. 　各前記光ＴＤＭ伝送装置は、前記データ信号とは前記物理的性質の異なる前記タイミング信号として、タイムスロット幅が前記データ信号とは異なる前記タイミング信号を受信することを特徴とする
    　請求項１に記載の光ＴＤＭ伝送装置。     According to claim 1, each of the optical TDM transmission devices receives the timing signal having a different time slot width from the data signal, as the timing signal having a physical property different from that of the data signal. optical TDM transmission equipment.
  4. 　各前記光ＴＤＭ伝送装置は、前記受信タイミングが記憶された後においても、各前記光ＴＤＭ伝送装置に対して送信される前記タイミング信号を受信し、受信した前記タイミング信号をもとに、記憶した前記受信タイミングを補正することを特徴とする
    　請求項１に記載の光ＴＤＭ伝送装置。     Even after the reception timing is stored, each optical TDM transmission device receives the timing signal transmitted to each optical TDM transmission device, and stores the timing signal based on the received timing signal. The optical TDM transmission device according to claim 1, wherein the reception timing is corrected.
  5. 　複数の光ＴＤＭ伝送装置が、ノード間のタイムスロットを同期した状態でデータ信号の送信を行う光ＴＤＭ伝送システムが実行する同期方法において、
    　各前記光ＴＤＭ伝送装置は、
    　前記データ信号とは物理的性質の異なるタイミング信号を受信し、受信した前記タイミング信号の受信時刻および受信周期を、前記タイミング信号の受信タイミングとして記憶し、
    　記憶された前記受信タイミングを基準にして把握したタイムスロットに、自身から送信される前記データ信号を重畳するように制御することを特徴とする
    　同期方法。     In a synchronization method performed by an optical TDM transmission system in which a plurality of optical TDM transmission devices transmit data signals while synchronizing time slots between nodes,
    Each of the optical TDM transmission devices includes:
    receiving a timing signal having different physical properties from the data signal, storing the reception time and reception period of the received timing signal as the reception timing of the timing signal;
    A synchronization method characterized in that the data signal transmitted from itself is controlled to be superimposed on a time slot grasped based on the stored reception timing.
  6. 　コンピュータを、請求項１ないし請求項４のいずれか１項に記載の光ＴＤＭ伝送装置として機能させるための同期プログラム。 A synchronization program for causing a computer to function as the optical TDM transmission device according to any one of claims 1 to 4.
PCT/JP2022/024087 2022-06-16 2022-06-16 Optical tdm transmission device, synchronization method, and synchronization program WO2023243031A1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
PCT/JP2022/024087 WO2023243031A1 (en) 2022-06-16 2022-06-16 Optical tdm transmission device, synchronization method, and synchronization program

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/JP2022/024087 WO2023243031A1 (en) 2022-06-16 2022-06-16 Optical tdm transmission device, synchronization method, and synchronization program

Publications (1)

Publication Number Publication Date
WO2023243031A1 true WO2023243031A1 (en) 2023-12-21

Family

ID=89192476

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/JP2022/024087 WO2023243031A1 (en) 2022-06-16 2022-06-16 Optical tdm transmission device, synchronization method, and synchronization program

Country Status (1)

Country Link
WO (1) WO2023243031A1 (en)

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20050117571A1 (en) * 2003-12-01 2005-06-02 Dyke Robert G. Distribution of time division multiplexed data through packet connections
CN101582734A (en) * 2008-05-14 2009-11-18 上海贝尔阿尔卡特股份有限公司 Access control method in wavelength division multiplexing passive optical network and device thereof
WO2013187474A1 (en) * 2012-06-13 2013-12-19 日本電信電話株式会社 Optical network system, optical switch node, master node, and node

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20050117571A1 (en) * 2003-12-01 2005-06-02 Dyke Robert G. Distribution of time division multiplexed data through packet connections
CN101582734A (en) * 2008-05-14 2009-11-18 上海贝尔阿尔卡特股份有限公司 Access control method in wavelength division multiplexing passive optical network and device thereof
WO2013187474A1 (en) * 2012-06-13 2013-12-19 日本電信電話株式会社 Optical network system, optical switch node, master node, and node

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
KOTA NISHIYAMA, MASAHIRO NAKAGAWA, TOSHIYA MATSUDA, KANA MASUMOTO, TAKESHI SEKI, TAKASHI MIYAMURA: "Proposal of Timing Adjustment Method to Realize High-precision Synchronization in Optical Time Division Multiplexing Transmission", IEICE TECHNICAL REPORT, PN, THE INSTITUTE OF ELECTRONICS, INFORMATION AND COMMUNICATION ENGINEERS, JP, vol. 122, no. 71 (PN2022-6), 3 June 2022 (2022-06-03), JP, pages 7 - 11, XP009551137 *

Similar Documents

Publication Publication Date Title
US9473836B2 (en) Maintaining channel-invariant optical network unit (ONU) equalization delay in a passive optical network
EP2283592B1 (en) Method and apparatus for controlling the optical output power from a burst mode laser
EP2675102B1 (en) Communication system time synchronization method, slave station apparatus, master station apparatus, control apparatus, and program
US11128940B2 (en) Transmission method for an optical burst transport network, slave node, and computer storage medium
US9025949B2 (en) Equalization delay agnostic protection switching in protected passive optical networks
US9806845B1 (en) Mitigating spectral excursions in passive optical networks
US9871614B2 (en) WDM/TDM-PON system and transmission start time correction method thereof
JP2007295151A (en) Pon system and station side apparatus and terminal used for the same
JP5889298B2 (en) Distributed measurement system and method in optical communication network
US10084592B2 (en) Skew calculation in channel-bonded passive optical networks (PONs)
WO2019109252A1 (en) Method for transmitting and receiving data in pon system, network device, and system
JP4173044B2 (en) Method of using upstream bandwidth in optical burst transmission / reception network
WO2023243031A1 (en) Optical tdm transmission device, synchronization method, and synchronization program
CN102740176B (en) Communication method and communication system
WO2023243030A1 (en) Optical tdm transmission device, synchronization method, and synchronization program
JP5420435B2 (en) Station side equipment
WO2023243029A1 (en) Optical tdm transmission device, synchronization method, and synchronization program
WO2023243028A1 (en) Optical tdm transmission device, synchronization method, and synchronization program
EP3474567B1 (en) Methods and products for onu start-up procedure
JP2017225018A (en) Subscriber side device, office side device, optical communication system, optical communication method and program
JP4893589B2 (en) PON system station side apparatus and frame processing method
Kamchevska et al. Synchronization algorithm for SDN-controlled all-optical TDM switching in a random length ring network
JP5684344B2 (en) Station side equipment
JP2019140657A (en) Optical line terminal, optical network unit, optical communication system, station side program, subscriber side program, and time synchronization program
JP2014121078A (en) Optical communication network system, and control method of optical communication network system

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 22946848

Country of ref document: EP

Kind code of ref document: A1