JP6506208B2 - Optical concentrator network system, optical transmission apparatus and optical transmission method - Google Patents

Description

  The present invention relates to a light concentration line in which communication between upper optical transmission devices and communication between lower and upper optical transmission devices are performed in parallel in a ring type network using PON (Passive Optical Network) or the like. The present invention relates to a network system, an optical transmission apparatus, and an optical transmission method.

  The PON is an optical network (a network is also referred to as NW) in which one optical fiber in which a branching device (optical coupler) is inserted in the middle of an optical fiber network can be shared by a plurality of subscribers. The NW to which this PON is applied is basically a tree type, and is not applied to the ring type. In PON, direct communication can not be performed between ONUs (Optical Subscriber Units) which are arbitrary nodes, and basically, only communication between an OSU and an ONU (Optical Network Unit) is supported. For this reason, communication between ONUs must necessarily go through the OSU.

  Here, in a PON in a broadband access network, an OSU in an Optical Line Terminal (OLT) disposed in a central office and an ONU disposed in a user's home are ring-connected via an optical fiber and an optical coupler. Usually, a plurality of ONUs are connected to one OSU, and time division multiplexing (TDM) or time division multiple access (TDMA) is applied between the OSUs and the ONUs to apply signals (data) in the optical domain. Transmit data while performing demultiplexing. Data transmission from multiple ONUs to one OSU is performed by burst signals because of TDMA. By such transmission, resources such as an optical fiber core and an OLT can be shared by a plurality of users.

  The OLT is an optical line termination apparatus (optical transmission apparatus) on the side of a central office, and the OSU is an optical line termination apparatus (upper order optical transmission apparatus) of a PDS (Passive Double Star) system. The ONU is a subscriber apparatus as an optical line termination apparatus (subordinate optical transmission apparatus) on the user home side.

  By the way, optical transport NW technology such as ring type NW to which PON is applied has been steadily advanced, and the optical path bandwidth has been developed from 10 Gbps to 100 Gbps. However, in the actual service, the data rate is 10 Gbps or less, and the service of 10 Gbps or more is predicted to have a traffic volume of several% of the total interface in the near future. Therefore, it is important to multiplex a lot of user traffic on one optical path from the viewpoint of NW cost.

  On the other hand, IP (Internet Protocol) edge routers connected to the Metro NW described later that perform various service processing including IP telephone services for general users have the problem of cost reduction per device and improvement of user accommodation efficiency The cloud edge that applies the virtualization technology to the IP edge router is being considered. The Metro NW is a communication network in an urban area that connects a data center of a communication carrier with a company or a building. The virtualization technology is a technology that enables resource sharing by migration of virtual machines according to resource usage between physically different devices. For example, resources can be shared between IP edge routers that are physically different. Due to migration of these virtual machines, it is expected that the traffic flowing into the future Metro NW will dynamically fluctuate, including the destination. For this reason, in the future Metro NW, cloud edge support and improvement of facility utilization efficiency are important.

The case where communication between OSUs accommodating such a virtualized cloud edge and communication between ONUs and OSUs are performed on a ring type NW to which PON is applied will be described.
FIG. 9 shows a light concentrating NW system (system) 10 as a ring type NW to which a conventional PON is applied. In this system 10, a plurality of optical transmission apparatuses 11 and 12 as physically independent upper apparatuses and a plurality of optical transmission apparatuses 13 and 14 as physically independent lower apparatuses are connected to an optical demultiplexing apparatus 16, It is connected in a ring shape by one optical fiber 20 as a signal transmission path via 17, 18 and 19. The optical transmission devices 11 and 12 are also referred to as upper devices 11 and 12, and the optical transmission devices 13 and 14 are referred to as lower devices 13 and 14.

  OSUs 21 and 22 having TX (transmitter) and BRX (burst receiver) connected to the optical demultiplexers 16 and 17 are arranged in the higher-level devices 11 and 12, respectively. The lower-level devices 13 and 14 are provided with ONUs 23 and 24 each having a BTX (burst transmitter) and an RX (receiver) connected to the optical demultiplexers 18 and 19, respectively. Further, external devices 25 and 26 such as computers are connected to the OSUs 21 and 22 via the core NW, and external devices 27 and 28 such as computers are connected to the ONUs 23 and 24 via the access NW. That is, the OSUs 21 and 22 terminate the signals transmitted to and received from the external units 25 and 26, and are optical line termination units serving as control entities. The ONUs 23 and 24 are optical line termination devices that terminate signals transmitted to and received from the external devices 27 and 28 and become objects to the control entity.

  Also, the cloud edge 30 connected to each of the OSUs 21 and 22 is virtualized so that it looks like one device. The cloud edge 30 dynamically switches the user accommodation position according to the resource utilization status of the device. The resource utilization status of the device is transmitted and received between the cloud edges. For this reason, it is necessary to communicate between the OSUs 21 and 22. Since it is assumed that the OSU of PON is transmitted as a continuous signal, this communication is performed by a continuous signal such as repeating “0” and “1”. For example, as indicated by a broken arrow Y1, a continuous signal of wavelength λ1 is transmitted from the TX of the OSU 21 to the OSU 22 through the optical fiber 20. The transmitted continuous signal Y1 is received by BRX of the OSU 22. FIG. 10A shows the waveform of the continuous signal Y1 that repeats “0” and “1”.

  On the other hand, the ONUs 23 and 24 shown in FIG. 9 communicate with the OSUs 21 and 22 using, for example, 10 Gbps Ethernet (registered trademark). The communication from the ONUs 23 and 24 is performed in a burst because it needs to be performed by the OSU 21 or 22 in a time division manner. For this reason, transmission from the ONUs 23 and 24 is performed using a burst signal Y2 whose example of waveform is shown in FIG. 10 (b). The burst signal Y2 is transmitted from the BTX of the ONU 24 to the OSU 22 through the optical fiber 20 at a wavelength λ2 different from the wavelength λ1, as indicated by a dashed-dotted arrow Y2 in FIG. The transmitted burst signal Y2 is received by BRX of the OSU 22.

  However, in this system 10, the continuous signal Y1 shown in FIG. 10 (a) transmitted from the TX of the OSU 21 and the burst signal Y2 shown in FIG. 10 (b) transmitted from the BTX of the ONU 24 are BRX of the OSU 22. If it is received, the following problems occur. As shown in FIG. 10 (c), both of the continuous signal Y1 and the burst signal Y2 received by BRX overlap, and since both are approximately the same level, both can not be received properly.

  Therefore, as techniques for properly receiving the continuous signal Y1 and the burst signal Y2 by the OSU 22, there are techniques described in Non-Patent Documents 1 and 2.

  The technique of Non-Patent Document 1 will be described by a system 10A shown in FIG. However, in FIG. 11, the same parts as those in FIG. In the technology of Non-Patent Document 1, RX and BRX are provided in each of the OSUs 21A and 22A in the system 10A shown in FIG. Then, the continuous signal Y1 transmitted from the TX of one of the OSUs 21A is received by the RX of the other OSU 22A, and the burst signal Y2 transmitted from the BTX of the ONU 24 is received by BRX. According to this technique, since the continuous signal Y1 and the burst signal Y2 are received by different receivers, the respective signals Y1 and Y2 can be received.

  The technique of Non Patent Literature 2 will be described by a system 10B shown in FIG. However, in FIG. 12, the same parts as those in FIG. In the technique of Non-Patent Document 2, in the system 10B shown in FIG. 12, each ONU 23, 24 communicating with each OSU 21, 22 is disposed in the optical transmission device 13A which is one lower device, and each ONU 23, 24 is arranged. Are connected via an L2 (layer 2) switch 29 that performs a relay operation. In this configuration, in communication between ONU and OSU, for example, a burst signal transmitted from BTX of ONU 23 is received by BRX of OSU 21 associated with ONU 23, and a burst signal transmitted from BTX of ONU 24 is associated with ONU 24 It is received by the BRX of the OSU 22.

  On the other hand, in inter-OSU communication, for example, the continuous signal Y1 transmitted from the TX of the OSU 21 is received by the RX of the ONU 23 associated with the OSU 21 and the received continuous signal Y1 is transmitted through the L2 switch 29 to the other. It is transmitted to the ONU 24. In the other ONU 24, the continuous signal Y1 is temporarily processed by BTX and transmitted to the OSU 22 as a burst signal Y1a. The burst signal Y1a is received by BRX of the OSU 22. Thus, communication between the OSUs 21 and 22 can be relayed by the two ONUs 23 and 24 connected by the L2 switch 29.

AV Tran et al., “Bandwidth-Efficient PON System for Broad-Band Access and Local Customer Internetworking,” IEEE Photon. Technol. Lett., [Online], Mar. 2006. [April 5, 2016 Search], Internet <URL: http://ieeexplore.ieee.org/xpls/abs_all.jsp?arnumber=1597291> AD Hossain et al., “Ring-based local access PON architecture for supporting private networking capabilities,” OSA J. OPT. NETW., Vol. 5, no. 1, pp. 26-39, [online], Jan. 2006 [Search on April 5, 2016], Internet <URL: https://www.osapublishing.org/jocn/abstract.cfm?uri=JON-5-1-26>

  By the way, in the above-described systems 10, 10A and 10B, it is assumed that communication is performed between two OSUs in addition to the communication between the ONU and the OSU. However, when the cloud edge connected to three or more OSUs is virtualized, it is necessary to communicate between the three or more OSUs in order to transmit and receive the resource utilization status of the device. For example, when performing communication between three OSUs, a case K1 in which data transmission is performed from one OSU to two other OSUs by continuous signals, and data transmitted by continuous signals from two other OSUs by one OSU There is a case K2 for receiving. In the case K2, the following problem occurs.

  In the system 10 shown in FIG. 9, when both the continuous signal Y1 and the burst signal Y2 are received by BRX of one OSU, both are overlapped and can not be received. When performing communication between the three or more OSUs in this system 10, in the case K2, two continuous signals having different wavelengths are received redundantly in one BRX, and therefore the timing at which the burst signal Y2 is not received is 2 Can not receive two continuous signals.

  In the system 10A shown in FIG. 11, a receiver is provided for each of the continuous signal Y1 and the burst signal Y2 to be transmitted, for example, RX for the continuous signal and BRX for the burst signal, and one reception The device receives one signal (continuous signal or burst signal). Therefore, even in the case K2 described above, two continuous signals and one burst signal may be received by two continuous reception interfaces RX and one BRX associated with each other. However, since it is necessary to deploy the L2 switch so that the continuous reception interface RX and the signals received from the respective continuous reception interfaces do not collide, the manufacturing cost of the OSU (optical transmission apparatus) is further increased.

  In the system 10B shown in FIG. 12, communication between the OSUs 21 and 22 is relayed by the two ONUs 23 and 24 connected by the L2 switch 29. However, when this relaying is performed in the above-described case K2, two continuous signals are temporarily processed by the BTX of the ONU 24 at the time of relaying and transmitted to the OSU 22 as two burst signals. If the transmission timings of the two burst signals are different, they can be received by the BRX of the OSU 22, but if the transmission timings are the same, they can not be received. Moreover, when performing the above-mentioned relay, it is necessary to once perform signal processing by each ONU23, 24 and L2 switch 29, and the transmission delay of a signal will increase by that much and reliability will fall. Furthermore, the transmission band of the signal addressed not only to two other continuous OSUs but also to the ONUs 23 and 24 is required. This results in increased bandwidth consumption.

  The present invention has been made in view of such circumstances, and communication between an upper optical transmission apparatus that receives two or more continuous signals with one burst receiver, and communication between lower and upper optical transmission apparatuses. An optical concentration network system capable of realizing both of the above so as not to cause an increase in signal transmission delay and band consumption, and so as not to increase the manufacturing cost of the optical transmission apparatus; An object of the present invention is to provide an apparatus and an optical transmission method.

  As means for solving the above-mentioned problems, the invention according to claim 1 is characterized in that a plurality of OSUs as optical line termination devices that terminate signals transmitted to and received from an external device and become control entities; However, in the configuration in which a plurality of ONUs as optical line terminal devices serving as objects are connected by an optical transmission path, inter-OSU communication that transmits continuous signals, ONU that transmits burst signals from ONUs, and inter-OSU communication Optical concentration network system in which the communication between the OSUs is performed between a plurality of OSUs, transmitted from the two or more other OSUs via the optical transmission line, and different at each reception A burst that receives and separates each successive signal of different wavelengths on which data is superimposed so as to be a position, and extracts only the data portion addressed to the OSU stored in each successive signal after this separation The reception processing unit that performs processing, a optical line network system, comprising external or internal of the OSU.

  According to this configuration, since the signal of the data portion of each continuous signal obtained by the burst processing is burst, it can be received by the burst receiver (BRX) of the OSU. Also, since data is superimposed on the continuous signal so that the data portion of each continuous signal is at a different position upon reception, it is possible to separately receive data from two or more other OSUs with one BRX. it can. Therefore, as in the conventional case, processing for relaying OSU communication with a plurality of ONUs connected by the L2 switch is unnecessary, and the increase in signal transmission delay and bandwidth consumption at the time of transmission is eliminated. be able to. That is, according to the present invention, communication between OSUs (upper optical transmission apparatuses) in which two or more continuous signals are received by one burst receiver, and between ONUs and OSUs (between lower and upper optical transmission apparatuses) Both with communication can be done such that there is no increase in transmission delay and bandwidth consumption of the signal.

  In the invention according to claim 2, the reception processing unit transmits from the ONU a reception timing different from the reception timing of the data superposition position of the continuous signal, and receives a burst signal of a wavelength different from the continuous signal. 2. The light concentration network system according to claim 1, wherein said continuous signal is separated.

  According to this configuration, the receiving side OSU separates the burst signal transmitted from the ONU by the reception processing unit from the continuous signal and receives it. The burst signal is transmitted from the ONU at a wavelength different from that of the continuous signal and at a reception timing different from the reception timing of the data superposition position of the continuous signal. Thus, the separated burst signal can be received by BRX so as not to overlap with the data of the continuous signal.

  In the invention according to claim 3, the OSU measures the distance or delay time between the OSUs to be communicated, and superimposes on continuous signals from the two or more other OSUs based on the measured distance or delay time. A transmission timing deriving unit for obtaining a transmission timing in each of the two or more other OSUs that enables reception of each piece of data so as not to overlap with the burst signal from the ONU; 3. The light concentration network system according to claim 2, wherein the transmission timing is transmitted to the two or more other OSUs and set to the corresponding other OSU.

  According to this configuration, at the time of inter-OSU communication, each OSU on the transmitting side does not overlap the data addressed to the other OSU with the burst signal at the time of reception by the OSU at the transmission timing set in each OSU. It can be sent to the receiving OSU so that the data addressed to the OSU does not overlap. Therefore, the receiving side OSU can receive each piece of data in the continuous signal from each transmitting side OSU and the individual data of the burst signal from the ONU so as not to overlap.

  In the invention according to claim 4, according to the set transmission timing, the OSU receives the reception timing of data to be superimposed on the continuous signal of the OSU on the other transmission side, and the reception timing of the burst signal from the ONU. 4. A light concentration network system according to claim 3, wherein data addressed to the receiving OSU is assigned to a time slot other than the time slot of the continuous signal corresponding to.

  According to this configuration, the transmitting OSU receives the data in the continuous signal from the other transmitting OSU received by the receiving OSU and the time slot position of the continuous signal not overlapping the burst signal. Data for OSU can be assigned. Therefore, each data in the plurality of continuous signals and the data in the burst signal can be properly received individually by the receiving side OSU.

  The invention according to claim 5 is characterized in that the OSU comprises a transmission control unit for adding a burst header detectable by a burst receiver disposed in the other OSU to a continuous signal transmitted to the other OSU. It is an optical concentration network system in any one of Claims 1-4.

  According to this configuration, a continuous signal can be received in a burst manner by detecting the burst header with an existing burst receiver (BRX) normally provided in the OSU. Therefore, it is possible to receive each of the burst signal and the continuous signal with one existing BRX. In the configuration of the present invention, as in the prior art, the OSU does not need two continuous reception interfaces RX and one BRX for separately receiving the continuous signal and the burst signal. Therefore, communication for receiving a burst signal and a continuous signal can be realized without increasing the manufacturing cost of the OSU (optical transmission apparatus).

  The invention according to claim 6 terminates a signal transmitted / received to / from an external device and becomes an object with respect to a plurality of higher-order optical transmission devices as optical line termination devices serving as control entities, and the control entities. In a configuration in which a plurality of low-order optical transmission devices as optical line termination devices are connected by an optical transmission line, communication with other high-order optical transmission devices is performed by continuous signal transmission and burst signal transmission Higher-order optical transmission devices that communicate with lower-order optical transmission devices that perform two-or-more-upper-order optical transmissions when communication between the upper-order optical transmission devices is performed between a plurality of higher-order optical transmission devices It receives and separates the continuous signals of different wavelengths on which data has been transmitted so as to be at different positions upon reception, which have been transmitted from the device via the optical transmission line, and are separated into the respective continuous signals after this separation. Data section for stored upper-level optical transmission device An optical transmission apparatus comprising: a reception processing unit that performs burst processing for extracting only.

  The invention according to claim 8 terminates a signal transmitted / received to / from an external device, and becomes an object with respect to a plurality of higher-order optical transmission devices as optical line termination devices serving as control entities, and the control entities. In a configuration in which a plurality of low-order optical transmission devices as optical line termination devices are connected by an optical transmission line, communication with other high-order optical transmission devices is performed by continuous signal transmission and burst signal transmission An optical transmission method by an upper optical transmission apparatus performing communication with a lower optical transmission apparatus, the upper optical transmission apparatus performing communication between the upper optical transmission apparatuses among a plurality of upper optical transmission apparatuses When performing this operation, receive continuous signals of different wavelengths on which data are superimposed so as to be at different positions during reception, which are transmitted from the two or more other superior optical transmission devices via the optical transmission path. Separating and each after separation An optical transmission method which is characterized in that execution of a higher-level stored in the continuous signal and performing a burst process for extracting only the data portion addressed to the optical transmission device.

  According to the configuration of claim 6 and the method of claim 8, since the signal of the data portion of each continuous signal obtained by the burst processing is burst, it can be received by the BRX of the upper optical transmission apparatus . In addition, since data is superimposed on the continuous signal so that the data portion of each continuous signal is at a different position at the time of reception, data from two or more other higher-level optical transmission devices can be individualized by one BRX. Can be received. For this reason, as in the prior art, the process of relaying the communication between the upper level optical transmission apparatuses with a plurality of ONUs connected by the L2 switch becomes unnecessary, and the signal transmission delay and the bandwidth consumption at the time of the transmission Can be eliminated. That is, according to the present invention, the signal transmission is performed for both the communication between the upper optical transmission apparatus that receives two or more continuous signals with one burst receiver and the communication between the lower and upper optical transmission apparatuses. It can be done to avoid delays and increased bandwidth consumption.

  The invention according to claim 7 includes a transmission control unit that adds a burst header detectable by a burst receiver provided in the upper optical transmission device to a continuous signal transmitted to another upper optical transmission device. It is an optical transmission device according to claim 6 characterized by things.

  According to this configuration, by detecting the burst header with the existing BRX, which is usually provided in the upper-layer optical transmission apparatus, the reception processing unit bursts out the signal that has been cut out from the continuous signal in a burst manner. It becomes receivable. Therefore, it is possible to receive each of the burst signal and the continuous signal with one existing BRX. According to the configuration of the present invention, unlike the prior art, the upper optical transmission apparatus does not need two continuous reception interfaces RX and one BRX for separately receiving the continuous signal and the burst signal. Therefore, communication for receiving a burst signal and a continuous signal can be realized without increasing the manufacturing cost of the optical transmission apparatus.

  According to the present invention, communication between the upper optical transmission apparatus for receiving two or more continuous signals with one burst receiver and communication between the lower and upper optical transmission apparatuses, as well as signal transmission delay and bandwidth It is possible to provide an optical concentration network system, an optical transmission apparatus, and an optical transmission method that can be performed so as not to cause an increase in consumption and can realize this communication without increasing the manufacturing cost of the optical transmission apparatus. .

FIG. 1 is a block diagram showing a configuration of a light concentration network system according to an embodiment of the present invention. It is a block diagram showing composition of OSU of a light concentration network system of this embodiment. (A) A waveform chart of a continuous signal, (b) A waveform chart of a burst signal obtained by bursting the continuous signal shown in (a). FIG. 6 is a waveform diagram of two burst signals and burst signals each having different reception timing. It is a block diagram which shows the structure of ONU of the optical concentration network system of this embodiment. It is a block diagram which shows the structure of the transmission control part in OSU. It is a block diagram which shows the structure of a reception process part. It is a sequence diagram for demonstrating the light transmission operation | movement of the light concentration network system of this embodiment. It is a block diagram which shows the structure of the conventional light concentration network system. (A) A waveform diagram of a continuous signal, (b) a waveform diagram of a burst signal, (c) a waveform diagram showing a state in which a continuous signal and a burst signal overlap. It is a block diagram which shows the other structure of the conventional light concentration network system. FIG. 6 is a block diagram showing another configuration of a conventional optical concentration network system.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
<Configuration of Embodiment>
FIG. 1 is a block diagram showing the configuration of a light concentration network system according to an embodiment of the present invention.
The light concentration network system (system) 40 shown in FIG. 1 constitutes a ring network to which the above-mentioned PON (Passive Optical Network) is applied. In this system 40, a plurality of optical transmission apparatuses 41a, 41b and 41c as physically independent upper apparatuses and a plurality of optical transmission apparatuses 42a, 42b and 42c as physically independent lower apparatuses are A single optical fiber 50 as a signal transmission path is connected in a ring shape via the separation devices 46a, 46b, 46c, 46d, 46e and 46f. The optical transmission devices 41a to 41c are also referred to as upper devices 41a to 41c, and the light transmission devices 42a to 42c are also referred to as lower devices 42a to 42c. Further, the higher-level devices 41a to 41c constitute a higher-order optical transmission device described in claims, and the lower-level devices 42a to 42c constitute a lower-order light transmission device described in claims.

  The host devices 41a to 41c are provided with OSUs 51a, 51b, and 51c each having a TX (transmitter) and a BRX (burst receiver) connected to the optical demultiplexers 46a to 46c. The TX of each of the OSUs 51a to 51c includes a transmission control unit 60 described later. In addition, between each of the BRXs and each of the optical demultiplexers 46a to 46c, a reception processing unit 62, which will be described later, connected between each of the BRXs and each of the optical demultiplexers 46a to 46c is provided. The transmission control unit 60 and the reception processing unit 62 are characteristic elements of the present embodiment.

  The lower devices 42a to 42c are provided with ONUs 53a, 53b, and 53c each having a BTX (burst transmitter) and an RX (receiver) connected to the optical demultiplexers 46d to 46f. Also, external devices 55a, 55b, 55c such as computers are connected to the OSUs 51a to 51c via the core NW, and external devices 57a, 57b, 57c such as computers are connected to the ONUs 53a to 53c via the access NW. ing. That is, the OSUs 51a to 51c are optical line termination devices that terminate signals transmitted to and received from the external devices 55a to 55c and become control entities. The ONUs 53a to 53c are optical line termination devices that terminate signals transmitted to and received from the external devices 57a to 57c and become objects with respect to the control entity.

  Also, the three OSUs 51a to 51c are connected to the virtualized cloud edge 30 to form one device. Here, the cloud edge 30 dynamically switches the user accommodation position according to the resource utilization status of the device. The resource utilization status of the device is transmitted and received between the cloud edges. For this reason, it is necessary to communicate between the three OSUs 51a to 51c. Since it is assumed that the OSU of PON is transmitted as a continuous signal, this communication is performed by a continuous signal such as repeating “0” and “1”.

  When performing communication between three OSUs by continuous signals, a case K1 of transmitting data by continuous signals from one OSU (for example, OSU 51a) to two other OSUs (for example, OSUs 51b and 51c) and two other OSUs (for example, For example, there is a case K2 in which data transmitted as a continuous signal from the OSU 51b and 51c) is received by one OSU (for example, the OSU 51c). The cases K1 and K2 correspond to the cases K1 and K2 in the above-mentioned "Problem to be solved by the invention". In this embodiment, although the case where communication is performed between three OSUs is described as an example, the present invention is similarly applicable to the case where communication is performed between three or more OSUs. For example, when communication is performed between four OSUs, in case K2, one OSU receives data transmitted in continuous signals from the other three OSUs.

  That is, in the case K2 of the communication between the three OSUs 51a to 51c, the continuous signals Y11a and Y11b different in the wavelengths λ1 and λ2 shown by the broken arrows Y11a and Y11b are transmitted from TX of the two OSUs 51a and 51b. Y 11 a and Y 11 b are received by the BRX of one OSU 51 c via the optical fiber 50. The continuous signals Y11a and Y11b are assumed to have a repetitive waveform of “0” and “1” similarly to the continuous signal Y1 illustrated in FIG. 10A.

  On the other hand, in the ONUs 53a to 53c shown in FIG. 1, one or more ONUs are associated with one OSU. For example, it is assumed that the ONU 53a is associated with the OSU 51a, the ONU 53b is associated with the OSU 51b, and the ONU 53c is associated with the OSU 51c. Also, the ONUs 53a to 53c communicate with, for example, 10 Gbps Ethernet. Communication from the ONUs 53a to 53c is performed in a burst manner because it is necessary to perform time divisions to the corresponding OSUs 51a to 51c. For example, as indicated by an arrow Y12 indicated by an alternate long and short dash line, a burst signal Y12 of a wavelength λ3 different from the wavelengths λ1 and λ2 is transmitted from the BTX of the ONU 53c to the OSU 51c through the optical fiber 50 and received by the BRX of the OSU 51c. The burst signal Y12 has the same waveform as the burst signal Y2 shown in FIG. 10 (b).

<Configuration of OSU>
Next, the configuration of the OSUs 51a to 51c will be described with reference to FIG. However, each of the OSUs 51a to 51c has the same configuration, and FIG. 2 shows the configuration of one OSU. The OSUs 51a to 51c include a buffer unit 81, a wavelength demultiplexing unit 82, a light on / off control unit 83, an optical burst reception unit 84 (BRX), a signal separation unit 85, a control information reception unit 86, and a counter. A management unit 87, a delay measurement unit 88, a selector unit 89, a clock synchronization unit 90, an internal clock unit 91, a band allocation unit 92, a TS (time slot) control unit 93, an optical transmission unit 94 (TX And is configured.

  However, the wavelength demultiplexing unit 82 and the light on / off control unit 83 are elements constituting the reception processing unit 62 connected to the input side of BRX of the OSUs 51a to 51c shown in FIG. 1, and in FIG. The mode deployed inside 51c is shown. That is, the reception processing unit 62 may be deployed either outside or inside the OSUs 51a to 51c.

  The buffer unit 81 distinguishes the data o1 addressed to the ONU and the data o2 addressed to the other OSU from the data received from the external devices 55a to 55c and separates the queue units (the queue unit 81a for ONU in FIG. 6, other OSU (Refer to the destination queue unit 81b). For example, in the OSU 51a, the buffer unit 81 identifies the ONU addressed data o1 addressed to the ONU 53a and the other OSU addressed data o2 addressed to the other OSU (OSU 51b, 51c) and stores them in separate queue units. The stored other OSU addressed data o2 is transmitted from the TX1 as a transmitter to the light transmitting unit 94 as the continuous signal i1 according to the transmission timing tc of the other OSU addressed data which is an instruction from the TS control unit 93. At the same time, the queue length information u1 is transmitted from the buffer unit 81 to the light transmission unit 94.

  On the other hand, when there is no instruction from the TS control unit 93, the buffer unit 81 inserts an idle signal (a meaningless signal) and continues transmitting the ONU-addressed data o1 from the TX1 as a transmitter as the continuous signal i1. In the case of the OSU 51a shown in FIG. 1, the continuous signal i1 corresponds to the continuous signal indicated by the broken line arrows Y11a and Y11b. Further, the buffer unit 81 shown in FIG. 2 receives the data i2 separated by the signal separation unit 85 at RX1 as a receiver, and transmits the received data i2 as the client signal o3 to the external device 56c. Note that by inserting the idle signal, it is possible to receive the signal from the OSU even with RX as a reception IF (interface) for continuous signals disposed on the ONU side.

  The wavelength demultiplexing unit 82 includes the wavelength λ1 of the continuous signal Y11a transmitted to the optical fiber 50 by another OSU (eg, OSU 51a), the wavelength λ2 of the continuous signal Y11b transmitted to the optical fiber 50 by another OSU (eg, OSU 51b), and the ONU. The wavelength λ3 of the burst signal Y12 transmitted from the ONU 53c to the optical fiber 50 is separated. In other words, it separates into three of the continuous signal Y11a, the continuous signal Y11b, and the burst signal Y12. The separated continuous signals Y11a and Y11b are input to the light on / off controller 83, and the burst signal Y12 is input to the optical burst receiver 84.

  The light on / off control unit 83 performs control to attenuate the input optical signal to turn off the output and to turn on the output to allow the optical signal to pass with the same power, and to be described later, VOA (Variable Optical) Attenuator: A variable optical attenuator or the like is applied. The light on / off control unit 83 receives data directed to the OSU superimposed on the continuous signals Y11a and Y11b separated by the wavelength demultiplexing unit 82 in accordance with the data arrival timing signals ma and mb which are instructions from the TS control unit 93. Control to extract and burst only the part.

  This control will be described more specifically. For example, in the continuous signal Y11a transmitted from the OSU 51a shown in FIG. 3A, it is assumed that data is stored (superimposed) in the time slot TSd between time t1 and t2. The continuous signal Y11a is demultiplexed by the optical demultiplexing device 46c shown in FIG. 2 and demultiplexed by the wavelength demultiplexing unit 82 of the OSU 51c, and is input to the optical on / off control unit 83. At this time, the light on / off control unit 83 follows the data arrival timing signal ma indicating the arrival of the data portion in the continuous signal Y11a, the continuous signal Y11a of only the data storage portion TSd shown in FIG. Extract as shown in b). The signal of the extracted data storage portion TSd is referred to as a burst signal B11a. At this time, the light on / off control unit 83 cuts the continuous signal Y11a except for the data storage portion TSd between time t1 and t2. Similarly, in the continuous signal Y11b transmitted from the OSU 51b, the data storage portion TSd is extracted to be a burst signal (B11b in FIG. 4).

  The optical burst reception unit 84 shown in FIG. 2 receives the burst signals B11a and B11b bursted by the light on / off control unit 83 and the burst signal Y12 from the ONU 53c and outputs the signal to the signal separation unit 85.

  The signal separation unit 85 separates the burst signals B11a and B11b and the burst signal Y12 into the data i2 and the control signal j1, outputs the data i2 to the RX1 of the buffer unit 81, and controls the control signal j1 to the control information reception unit 86. Output to

  The control information receiving unit 86 extracts the clock signal q1 based on the control signal j1 from the other OSUs 51a and 51b and outputs the clock signal q1 to the clock synchronization unit 90. The clock synchronization unit 90 outputs the clock signal ck1 to the selector unit 89 in synchronization with the clock signal q1. Further, the control information receiving unit 86 outputs the allocation TS information f1 to the TS control unit 93 according to the control signal j1. The control information receiving unit 86 also outputs, to the delay measuring unit 88, time stamp values ea and eb indicating the transmission time described in the control signal j1 from the other OSUs 51a and 51b.

  Furthermore, the control information receiving unit 86 selects one of the clock signal ck1 from the clock synchronization unit 90 and the clock signal ck2 from the internal clock unit 91 of its own OSU 51c according to the control signal j1 from the other OSUs 51a and 51b. The selection control signal p1 is output to the selector unit 89. The selector unit 89 selects the clock signal ck1 or ck2 according to the selection control signal p1 and outputs it to the counter management unit 87. Further, the control information receiving unit 86 outputs the reference time c to the counter managing unit 87.

  The counter managing unit 87 increments the reference value corresponding to the reference time c according to the clock signal ck1 or ck2 selected by the selector unit 89 to generate the counter value g1, and the counter value g1 is used as the delay measuring unit 88 and TS Output to control unit 93.

  The delay measurement unit 88 uses the time stamp values ea and eb indicating the transmission time described in the control signal j1 from the other OSUs 51a and 51b, and the counter value g1 from the counter management unit 87, and determines the distance between the OSUs 51a and 51c. (Or delay time) na and the distance (or delay time) nb between the OSUs 51b and 51c are measured and output to the TS control unit 93. The distance (or delay time) na between the OSUs 51a and 51c is referred to as an inter-OSU distance na, and the distance (or delay time) nb between the OSUs 51b and 51c is referred to as an inter-OSU distance nb. Here, the RTT (Round-TripTime), which is applied from when the signal is sent to each of the other OSUs 51a and 51b of the communication partner until the response comes back, is measured to measure the OSU distance na and the OSU distance nb. .

  The delay measurement unit 88 also measures the distance (or delay time) nn between each of the ONUs 53 a to 53 c and each of the OSUs 51 a to 51 c and outputs the measured distance to the TS control unit 93. The distance (or delay time) nn between each ONU 53a to 53c and each OSU 51a to 51c is also referred to as an ONU-OSU distance nn.

  The band allocation unit 92 detects the transmission traffic amount k1 of each of the OSUs 51a to 51c and each of the ONUs 53a to 53c received by the control information receiving unit 86, and the OSUs 51a to 51c and each of the ONUs 53a to 53c are detected from the transmission traffic amount k1. Calculate the bandwidth amount s1 to be allocated to the TS control unit 93.

  Based on the counter value g1 from the counter management unit 87 and the OSU distance na and the OSU distance nb, the TS control unit 93 uses the transmission timing ta for the other OSU 51a to transmit the data o2 addressed to the OSU to the OSU 51c. The other OSU 51b calculates the transmission timing tb for transmitting the data o2 addressed to the OSU to the own OSU 51c, and notifies the light transmitter 94 of the transmission timing tb.

  Further, the TS control unit 93 calculates transmission timings tan and tbn for the other OSUs 51a and 51b to transmit the data 01 addressed to the ONU to the ONUs 53a and 53b based on the counter value g1 and the ONU-OSU distance nn. And notify the light transmitter 94. Each transmission timing ta, tb, tan, tbn is notified, for example, as a time stamp. Also, the bandwidth amount s1 allocated to the communication between the OSUs 51a to 51c and the communication between the OSUs 51a to 51c and the ONUs 53a to 53c is notified to the light transmitting unit 94.

  Here, at each of the transmission timings ta and tb described above, each data o2 transmitted from the TX of the other OSU 51a and 52b as the continuous signal Y11a and Y11b at this timing ta and tb is a burst shown in FIG. 4 by BRX of its own OSU 51c. It is the timing which does not collide with each other (or does not overlap) when received as the modulation signals B11a and B11b. In addition, the timing is set so as not to collide with the burst signal Y12 shown in FIG. 4 from the ONU 53c received by BRX of the same OSU 51c. That is, as shown in FIG. 4, each transmission timing ta, tb and burst signal transmission timing from the ONU 53c are timing when each of the burst signals B11a, B11b and the burst signal Y12 do not collide upon reception. .

  The transmission timing ta is transmitted from the own OSU 51c to the other OSU 51a and set in the TX of the other OSU 51a, and the transmission timing tb is transmitted from the own OSU 51c to the other OSU 51b and set in the TX of the other OSU 51b. After these settings, the data o2 of the OSU 51a is superimposed on the continuous signal Y11a at the transmission timing ta and transmitted to the other OSU 51c, and the data o2 of the OSU 51b is superimposed on the continuous signal Y11b at the transmission timing tb and transmitted to the other OSU 51c Be done.

  In other words, data o2 superimposed on the continuous signal Y11a to be transmitted is shown in FIG. 4 corresponding to the reception timing of the data o2 superimposed on the other continuous signal Y11b and the reception timing of the burst signal Y12 from the ONU 53c. It is allocated to a time slot TSa other than the time slots TSb and TSn, and is transmitted to the other OSU 51c.

Also, data o2 superimposed on continuous signal Y11b is assigned to time slots TSb other than time slots TSa and TSn corresponding to the reception timings of data o2 and burst signal Y12 superimposed on another continuous signal Y11a, respectively. , To the other OSU 51c.
Also, the burst signal Y12 transmitted from the ONU 53c is assigned to the time slot TSn other than the time slot TSa or TSb corresponding to the reception timing of each data o2 superimposed on the continuous signal Y11 a or Y11 b, and transmitted to the other OSU 51 c Be done.

  The optical transmission unit 94 shown in FIG. 2 has a counter value g1, a bandwidth amount s1, transmission timings ta and tb at the time of communication between each OSU 51a to 51c, and transmission timings at the time of communication between the other OSU 51a and each ONU 53a, 53b and 53c. It imparts tan and tbn to the continuous signal i1 which is an optical signal, and transmits it to the other OSUs 51a and 51b via the optical demultiplexing device 46c. Similarly to this transmission, according to the counter value g1 transmitted from the other OSU 51a, 51b to the own OSU 51c and set in the light transmission unit 94, the bandwidth amount s1, and the transmission timing tc, tcn, The o1 and other OSU addressed data o2 is added to the continuous signal i1 and transmitted to the ONU 53c and the other OSUs 51a and 51b. The continuous signal i1 corresponds to the continuous signals Y11a and Y11b from the OSUs 51a and 51b shown in FIG. The delay measuring unit 88 and the TS control unit 93 constitute a transmission timing deriving unit (see reference numeral 93T in FIG. 7) recited in the claims.

<Configuration of ONU>
Next, the configuration of the ONUs 53a, 53b, 53c will be described with reference to FIG. Each ONU 53a to 53c has the same configuration, and FIG. 5 shows the configuration of one ONU. The ONUs 53a to 53c include a buffer unit 71, an optical reception unit 72 (RX), a signal separation unit 73, a control information reception unit 74, a clock synchronization unit 75, a counter management unit 76, and a TS control unit 77. And an optical burst transmitter 78 (BTX).

  The buffer unit 71 accumulates the data o5 received from any one of the external devices 57a to 57c, and outputs the accumulated data o5 as data i5 from the transmitter TX2 to the light burst transmitter 78. . Also, the data i6 is received from the signal separation unit 73 by the receiver RX2 and transmitted as data o6 to the external devices 57a to 57c. Further, queue length information k2 for each of the OSUs 51a to 51c, which is each destination, is output from the buffer unit 71 to the optical burst transmission unit 78.

The light receiving unit 72 receives a continuous signal (for example, the continuous signal Y11a) from the OSU (for example, the OSU 51a).
The signal separation unit 73 separates the received continuous signal Y 11 a into data i 6 and a control signal j 3, and outputs the control signal j 3 to the control information reception unit 74 and the data i 6 to the buffer unit 71.

  The control information receiving unit 74 receives the control signal j3 and outputs the reference timing c2 from the OSU 51a and the TDM control timing d2 according to the usage route to the counter managing unit 76, and also assigns the assigned TS from the OSU 51a. The information f2 is output to the TS control unit 77.

The clock synchronization unit 75 synchronizes the clock signal of its own ONU (for example, the ONU 53a) with the downstream signal b2 corresponding to the continuous signal Y11a from the OSU 51a.
The counter management unit 76 increments the reference value corresponding to the reference timing c2 from the OSU 51a according to the clock signal ck3 from the clock synchronization unit 75, and increments the counter value g2 obtained by the TS control unit 77 and the optical burst transmission unit 78. Output to

  The TS control unit 77 controls the TS transmission operation of the optical burst transmission unit 78 by comparing the counter value g2 with the timing value described in the allocation TS information f2 in accordance with the allocation TS information f2 from the OSU 51a. Ask for The control signal h2 controls the light burst transmission unit 78 to perform a TS transmission operation.

  The optical burst transmission unit 78 combines the data to be transmitted to the OSU (for example, the OSU 51c) and the control signal (including the current time), and generates an optical burst signal at a wavelength according to the control instruction by the control signal h2 of the TS control unit 77. Y12 is transmitted to the OSU 51c via the optical demultiplexer 46f.

<Configuration of Transmission Control Unit>
Next, the transmission control unit 60 of the present feature provided in the OSUs 51a to 51c will be described with reference to FIG. However, the transmission control unit 60 of the OSU 51a will be described as a representative. The TX (corresponding to the optical transmitter 94 in FIG. 2) of the OSU 51a includes the transmission controller 60, and includes a P / S (parallel / serial) converter 94a and a TX driver 94b on the output side of the transmission controller 60. . The transmission control unit 60 is configured to include a selector 60a, a burst addition unit 60b, a multiplexer 60c, and an idle addition unit 60d. The buffer unit 81 (see FIG. 2) is connected to the input side of the selector 60a.

  The buffer unit 81 includes an ONU queue unit 81a that stores ONU-addressed data (symbol o1 in FIG. 2) and another OSU queue unit 81b that stores other OSU-addressed data (symbol o2 in FIG. 2). . Here, the other OSUs are the OSUs 51b and 51c. The stored data for the ONU and the data for the other OSU are both superimposed on the continuous signal Y11a and transmitted from the TX (optical transmission unit 94) to the optical fiber 50 via the optical demultiplexer 46. Before transmission, the transmission control unit 60 performs the following processing. That is, the data addressed to the other OSU is transmitted in accordance with the designated time slot timing, the data addressed to the ONU is transmitted at other times, and the idle signal is transmitted if there is no data addressed to the OSU and the ONU.

  The selector 60a selects the ONU addressed data output from the ONU queue unit 81a when, for example, the “L” level of the selection control signal st1 indicating the transmission timing of ONU addressed data is supplied from the buffer unit 81. Output to the multiplexer 60c. On the other hand, the selector 60a receives the other OSU output from the other OSU queue unit 81b when, for example, the “H” level of the selection control signal st1 indicating the transmission timing of the data addressed to the other OSU is supplied from the buffer unit 81. The destination data is selected and output to the burst adding unit 60b.

  The burst adding unit 60b adds a burst header as a preamble to a forward time slot of data destined for another OSU to be superimposed on the continuous signal Y11a. This burst header can receive data addressed to other OSUs, and can receive data addressed to other OSUs superimposed on the continuous signal Y11a by the BRX of other OSUs 51b and 51c. For example, determination of arrival of data, threshold processing described later, signal Is a data signal for performing reset processing and the like. In order to enable these signal processing, a burst addition unit 60b adds a burst header to the continuous signal Y11a to perform a burst signal format that enables reception processing of the continuous signal to BRX.

  However, the other OSU-addressed data to the other OSUs 51b and 51c superimposed on the continuous signal Y11a is transmitted according to the transmission timing ta set to the TX of the own OSU 51a as described above. However, as with the transmission timing ta, the transmission timing transmitted from the other OSU 51b is also set in the local OSU 51a.

  For example, at the transmission timing ta from the own OSU 51a to the other OSU 51c, the other OSU addressed data superimposed and transmitted on the continuous signal Y11a is received by the other OSU 51c. That is, a continuous signal in which the data transmitted from the own OSU 51a as the continuous signal Y11a does not collide with the data superimposed from the other OSU 51b on the continuous signal Y11b and the burst signal Y12 transmitted from the ONU 53c. It is superimposed on the time slot position of Y11a. A burst header is added to the front of this time slot position.

  This addition is further described. For example, the data addressed to the other OSU to the other OSU 51c superimposed on the continuous signal Y11a is the reception timing of the data destined to the other OSU superimposed on the continuous signal Y11b from the other OSU 51b and the burst signal from the ONU 53c according to the transmission timing ta. It is allocated to time slots TSa (FIG. 4) other than time slots TSb and TSn (FIG. 4) corresponding to each of the reception timing of Y12. Therefore, the burst header is added to the forward time slot of the time slot TSa. Similarly to this, the burst header is added to the forward time slot of the time slot TSb in which the data addressed to the other OSU is allocated to the other OSU 51 b.

  The multiplexer 60c multiplexes the continuous signal Y11a on which data destined to the ONU is superimposed and the continuous signal Y11a on which data destined to the other OSU is superimposed on the other OSUs 51b and 51c and to which the burst header is added, to the idle adding unit 60d. Output. If a non-signal section exists in the multiplexed continuous signal Y11a, the idle adding unit 60d inserts an idle signal having the same waveform as the continuous signal in the non-signal section to perform processing to fill the non-signal section. In other words, the continuous signal Y11a is processed to eliminate the non-signal section and to perform continuous signal processing.

  The continuous signal Y11a processed by the idle addition unit 60d is converted to a continuous signal Y11a of a predetermined power predetermined by the TX driver 94b after being subjected to parallel / serial conversion by the P / S conversion unit 94a. It is transmitted to the optical fiber 50 via the device 46a.

<Configuration of Reception Processing Unit>
Next, the reception processing unit 62 of the present feature will be described in detail with reference to FIG. The reception processing unit 62 is connected between the BRX of the OSU 51c (or the OSUs 51a and 51b) and the optical demultiplexer 46c (or the optical demultiplexers 46a and 46b). The reception processing unit 62 includes a wavelength filter 62e (corresponding to the wavelength demultiplexing unit 82 in FIG. 2) and VOAs 62a and 62b (corresponding to the light on / off control unit 83 in FIG. 2) using magneto-optical elements and the like. And an optical coupler 62d. The OSU 51c (or the OSUs 51a and 51b) includes the transmission timing deriving unit 93T by the delay measuring unit 88 and the TS control unit 93 (FIG. 2) described above.

  In the wavelength filter 62e, the continuous signal Y11a of the wavelength λ1 and the continuous signal Y11b of the wavelength λ2 separated by the optical multiplexer / demultiplexer 46c from the OSUs 51a and 51b (FIG. 1) via the optical fiber 50; And the burst signal Y12 of the wavelength λ3 separated by the optical demultiplexing device 46c. The wavelength filter 62e separates the three signals of the input continuous signal Y11a, continuous signal Y11b, and burst signal Y12, outputs the continuous signal Y11a to the VOA 62a, the continuous signal Y11b to the VOA 62b, and the burst signal Y12 as an optical coupler Output to 62d.

  When the control current is not supplied to the magneto-optical element, the VOA 62a and 62b outputs the input optical signal with the same power. When a control current is supplied to the magneto-optical element, the light signal is attenuated according to the amount of the current. Here, an optical signal can be cut like the continuous signal Y11a described in FIGS. 3A and 3B by supplying a control current of a predetermined current amount to the magneto-optical element in advance.

  VOAs 62a and 62b shown in FIG. 7 are data superimposed on the continuous signals Y11a and Y11b demultiplexed by the wavelength demultiplexing unit 82 in accordance with the data arrival timing signals ma and mb, which are instructions from the transmission timing deriving unit 93T of the OSU 51c. Only the portion is extracted and bursted, and the burst signals B11a and B11b are output to the optical coupler 62d. The optical coupler 62d multiplexes the burst signals B11a and B11b and the burst signal Y12 and outputs the multiplexed signal to the BRX of the OSU 51c.

  However, the data arrival timing signals ma and mb are generated by the transmission timing deriving unit 93T according to the delay measurement results measured between OSUs and the slots allocated to each OSU.

<Optical transmission operation of the embodiment>
Next, the light transmission operation by the light concentration network system 40 will be described with reference to the sequence diagram shown in FIG.

  In step S1 of FIG. 8, the continuous signal Y11a of the wavelength λ1 on which data directed to the ONU is superimposed is transmitted from the TX of the OSU 51a to the ONU 53a associated with the OSU 51a via the optical fiber 50. Also, a continuous signal Y11a on which data addressed to the other OSU is superimposed from the TX of the OSU 51a to each of the other OSUs 51c and 51b is transmitted via the optical fiber 50. These transmissions are performed by time division multiplexing of data to each destination on the continuous signal Y11a.

  Further, in step S2, the continuous signal Y11b of the wavelength λ2 on which the data addressed to the ONU is superimposed is transmitted from the TX of the OSU 51b to the ONU 53b associated with the OSU 51b via the optical fiber 50. Further, a continuous signal Y11b in which data directed to the other OSU is superimposed from the TX of the OSU 51b to each of the other OSUs 51a and 51c is transmitted via the optical fiber 50. These transmissions are performed by time division multiplexing of data to each destination on the continuous signal Y11b.

  In step S3, a continuous signal Y11c of a wavelength λc (not shown) different from the wavelengths λ1 to λ3 on which data directed to the ONU is superimposed from the TX of the OSU 51c to the corresponding OSU 51c via the optical fiber 50. Will be sent. In addition, a continuous signal Y11c in which data directed to the other OSU is superimposed from the TX of the OSU 51c to each of the other OSUs 51b and 51a is transmitted via the optical fiber 50. These transmissions are performed by time division multiplexing of data to each destination on the continuous signal Y11c.

  Further, in step S4, data addressed to the OSU is transmitted by the burst signal Y12 from the BTX of the ONU 53a to the OSU 51a. Further, in step S5, the data addressed to the OSU is transmitted by the burst signal Y12 from the BTX of the ONU 53b to the OSU 51b. Further, in step S6, data addressed to the OSU is transmitted by the burst signal Y12 from the BTX of the ONU 53c to the OSU 51c. In addition, since the data addressed to the OSU is transmitted by time division as the plurality of burst signals Y12, the burst signal Y12 is represented by a plurality of one-dot chain arrow Y12 in steps S4 to S6.

  In the continuous signal Y11a transmitted from the OSU 51a to the other OSU 51c in the above step S1, for example, data addressed to the other OSU of the OSU 51a is allocated to the time slot TSa (see FIG. 4) of the continuous signal Y11a Be done. The time slot TSa corresponds to the reception timing of the data addressed to the other OSU superimposed on the other continuous signal Y11 b in the continuous signal Y11 a and the time slots TSb and TSn corresponding to the reception timing of the burst signal Y12 from the ONU 53 c (FIG. Time slot other than. Similarly, data addressed to the other OSU of the OSU 51a is also assigned to the continuous signal Y11a transmitted to the other OSU 51b. Also in the steps S2 and S3, data addressed to other OSUs are similarly assigned. The subsequent processing will be described on behalf of the transmission of the OSU 51a and the reception of the OSU 51c.

  As described above, after the data destined for another OSU is assigned, the OSU 51a performs the following burst header addition processing. That is, the OSU 51a causes the transmission control unit 60 (FIG. 6) to add a burst header to the previous stage where data destined for the other OSU is superimposed on the other OSU 51c of the continuous signal Y11a. As a result, the reception processing unit 62 at the front stage of the BRX of the other OSU 51c can make it possible to burst and receive the data superimposed portion addressed to the other OSU of the continuous signal Y11a.

  The burst formation is performed by the VOA 62a of the reception processing unit 62 shown in FIG. The VOA 62a extracts only the data portion superimposed on the continuous signal Y11a demultiplexed by the wavelength demultiplexing unit 82 in accordance with the data arrival timing signal ma that is an instruction from the transmission timing deriving unit 93T of the OSU 51c, and generates a burst signal Output B11a. The data arrival timing signal ma is generated based on the burst header added to the front stage of the data superimposing portion on the continuous signal Y 11 a and the other OSU 51 c.

  Also in the other VOAs 62b, only the data portion superimposed on the continuous signal Y11b demultiplexed by the wavelength demultiplexing unit 82 is extracted in accordance with the data arrival timing signal mb, and is made a burst signal B11b.

  The burst signals B11a and B11b and the burst signal Y12 from the ONU 53c are independent of each other in timing as shown in FIG. 4, and are multiplexed by the optical coupler 62d and received by the BRX of the OSU 51c. .

<Effect of the embodiment>
As described above, as shown in FIG. 1, the optical concentration network system 40 according to the embodiment terminates the signal transmitted / received to / from the external devices 55a to 55c, and serves as an optical line termination device serving as a control subject. In a configuration in which a plurality of OSUs 51a to 51c and a plurality of ONUs 53a to 53c as optical line terminal devices serving as objects with respect to the control entity are connected by the optical fiber 50, transmission is performed by continuous signals The communication between the OSUs 51a to 51c, the communication between the ONUs 53a to 53c transmitted from the ONUs 53a to 53c by the burst signal Y12, and the communication between the OSUs 51a to 51c are performed in parallel. The features of the present invention will be described below.

  (1) The reception processing unit 62 is provided outside or inside the OSU. When communication between OSUs is performed between a plurality of OSUs 51a to 51c, the reception processing unit 62 transmits different positions during reception, which are transmitted from the two or more other OSUs 51a and 51b via the optical transmission path. Bursting processing that receives and separates the continuous signals Y11a and Y11b of different wavelengths on which data is superimposed, and extracts only the data portion addressed to the OSUs 51a to 51c stored in the continuous signals Y11a and Y11b after the separation. I do.

  According to this configuration, since the signals of the data portions of the continuous signals Y11a and Y11b obtained by the burst processing are burst, they can be received by the BRX of the receiving side OSU 51c. Also, since the data portion of each continuous signal Y11a and Y11b is superimposed on the continuous signal so that they are at different positions upon reception, data from two or more other OSUs 51a and 51b can be individualized with one BRX. Can be received. Therefore, as in the conventional case, processing for relaying the communication between the OSUs 51a and 51c with the plurality of ONUs 53c connected by the L2 switch is unnecessary, and the signal transmission delay and the band consumption at the time of transmission increase as in the prior art. Can be eliminated. That is, according to this configuration, communication between OSU 51a to 51c (upper optical transmission device) that receives two or more continuous signals Y11a and Y11b with one BRX, and between ONU 53c and OSU 51c (lower and upper optical transmission devices Both inter-communications can be done such that there is no increase in signal transmission delay and bandwidth consumption.

  (2) The reception processing unit 62 is transmitted from the ONU 53c to the reception timing different from the reception timing of the data superposition position of the continuous signals Y11a and Y11b, and receives the burst signal Y12 of a wavelength different from the continuous signals Y11a and Y11b It is separated from the continuous signals Y11a and Y11b.

  As a result, the receiving side OSU 51c separates the burst signal Y12 transmitted from the ONU 53c by the reception processing unit 62 from the continuous signals Y11a and Y11b and receives them. The burst signal Y12 is transmitted from the ONU 53c at a different wavelength from the continuous signals Y11a and Y11b and at a reception timing different from the reception timing of the data superposition position of the continuous signals Y11a and Y11b. For this reason, the separated burst signal Y12 can be received by BRX so as not to overlap the data of the continuous signals Y11a and Y11b.

  (3) The receiving side OSU 51c measures the distance or delay time with the OSUs 51a, 51b to be communicated, and based on the measured distance or delay time, a continuous signal from two or more other OSUs 51a, 51b The transmission timing deriving unit 93 T determines transmission timings ta and tb in each of the two or more other OSUs 51 a and 51 b that can receive each data superimposed on Y 11 a and Y 11 b so as not to overlap the burst signal Y 12 from ONU 53 c. Prepare. The transmission timings ta and tb determined by the transmission timing deriving unit 93T are transmitted to the two or more other OSUs 51a and 51b and set in the corresponding other OSUs 51a and 51b.

  As a result, at the time of communication between the OSUs 51a to 51c, the OSUs 51a and 51b on the transmission side transmit burst data Y12 when receiving data addressed to the other OSU 51c at the transmission timings ta and tb set in the OSUs 51a and 51b. Can be transmitted to one receiving OSU 51 c so that the data addressed to each other's OSU 51 c do not overlap. Therefore, the receiving side OSU 51c can receive each data in the continuous signals Y11a and Y11b from the transmitting OSUs 51a and 51b and the burst data Y12 from the ONU 53c so as not to overlap each other. .

  (4) Reception timings of data superimposed on the continuous signal Y11a or 11b of the OSU 51a or 51b on the other transmission side according to the transmission timing set by the OSUs 51a and 51b, and reception timing of the burst signal Y12 from the ONU 53c The data addressed to the receiving side OSU 51c is allocated to time slots other than the time slots of the continuous signals Y11a and Y11b corresponding to.

  According to this configuration, the transmitting OSUs 51a and 51b do not overlap the data in the continuous signal Y11a or 11b from the other transmitting OSU 51a or 51b received by the receiving OSU 51c and the burst signal Y12. Data can be assigned to the receiving side OSU 51 c at the time slot position of Y 11 a or 11 b. Therefore, the data in the plurality of continuous signals Y11a and 11b and the data in the burst signal Y12 can be properly and individually received by the receiving side OSU 51c.

  (5) The OSUs 51a and 51b include the transmission control unit 60 that adds a burst header detectable by the BRX deployed in the other OSU 51c to the continuous signals Y11a and 11b transmitted to the other OSU 51c.

  As a result, the continuous signals Y11a and 11b can be received in a burst manner by detecting the burst header with the existing BRX normally deployed in the OSU 51c (or one of the OSUs 51a and 51b). Therefore, it is possible to receive each of the burst signal Y12 and the continuous signals Y11a and 11b with one existing BRX. In this configuration, as in the prior art, the OSU 51c does not need a receiver such as RX and an expensive BRX that separately receive the continuous signals Y11a and 11b and the burst signal Y12. Therefore, communication for receiving the burst signal Y12 and the continuous signals Y11a and 11b can be realized such that the manufacturing cost of the OSUs 51a to 51c (optical transmission device) does not increase.

  In addition, about a specific structure, it can change suitably in the range which does not deviate from the main point of this invention.

40 Optical Concentration Network System 41a, 41b, 41c Upper Optical Transmission Device 42a, 42b, 42c Lower Optical Transmission Device 46a, 46b, 46c, 46d, 46e, 46f Optical Demultiplexer 50 Optical Fiber 51a, 51b, 51c OSU
53a, 53b, 53c ONU
55a, 55b, 55c, 57a, 57b, 57c External device 60 Transmission control unit 60a Selector 60b Burst addition unit 60c Multiplexer 60d Idle addition unit 62 Reception processing unit 62a, 62b VOA
62d optical coupler 62e wavelength filter 71 buffer unit 72 optical reception unit 73 signal separation unit 74 control information reception unit 75 clock synchronization unit 76 counter management unit 77 TS control unit 78 optical burst transmission unit 81 buffer unit 82 wavelength demultiplexing unit 83 optical on・ Off control unit 84 Optical burst reception unit 85 Signal separation unit 86 Control information reception unit 87 Counter management unit 88 Delay measurement unit 89 Selector unit 90 Clock synchronization unit 91 Internal clock unit 92 Band allocation unit 93 TS control unit 94 Optical transmission unit

Claims (8)

A plurality of OSUs as optical circuit termination devices that terminate signals transmitted to and received from external devices, and a plurality of ONUs as optical circuit termination devices that become objects to the control entity An optical concentration network system in which an inter-OSU communication that transmits continuous signals and an ONU that transmits burst signals from ONUs and an inter-OSU communication are performed in parallel in a configuration connected by a transmission path,
When the inter-OSU communication is performed between a plurality of OSUs, two or more other OSUs have been transmitted via the optical transmission line, of different wavelengths superimposed with data so as to be at different positions during reception. A reception processing unit is provided outside or inside the OSU that performs burst processing for receiving and separating each continuous signal and extracting only a data portion addressed to the OSU stored in each separated continuous signal. Optical concentrator network system characterized by The reception processing unit
The ONU is transmitted so as to have a reception timing different from the reception timing of the data superposition position of the continuous signal from the ONU, receives a burst signal of a wavelength different from the continuous signal, and separates it from the continuous signal. The light concentration network system according to 1. The OSU is
A distance or delay time between OSUs to be communicated is measured, and each data superimposed on continuous signals from the two or more other OSUs based on the measured distance or delay time is a burst signal from the ONU A transmission timing deriving unit for obtaining transmission timings in each of the two or more other OSUs, which can be received so as not to overlap with each other;
The light concentration network system according to claim 2, wherein the transmission timing determined by the transmission timing deriving unit is transmitted to the two or more other OSUs and set to the corresponding other OSU. . The OSU is
A time other than the time slot of the continuous signal corresponding to the reception timing of data to be superimposed on the continuous signal of the OSU on the other transmission side and the reception timing of the burst signal from the ONU according to the set transmission timing. 4. The optical concentration network system according to claim 3, wherein data addressed to the receiving OSU is assigned to the slot. The OSU is
The transmission control part which adds a burst header detectable by the burst receiver arrange | positioned at the said other OSU to the continuous signal transmitted to other OSU is provided, The any one of the Claims 1-4 characterized by the above-mentioned. Optical concentration network system. A plurality of high-order optical transmission devices as optical line termination devices that terminate signals transmitted to and received from an external device, and a plurality of optical line termination devices that become objects to the control entity In a configuration in which a lower optical transmission device is connected by an optical transmission path, communication with another upper optical transmission device is performed by transmitting a continuous signal and performing a burst signal transmission, and It is a high-level optical transmission device that communicates,
When communication between the upper level optical transmission devices is performed between a plurality of upper level optical transmission devices, positions transmitted from the two or more other upper level optical transmission devices via the optical transmission path are different positions upon reception. Burst processing for receiving and separating continuous signals of different wavelengths on which data are superimposed, and extracting only the data portion addressed to the upper optical transmission apparatus stored in each continuous signal after the separation. An optical transmission apparatus comprising: a reception processing unit to perform. 7. The transmission control unit according to claim 6, further comprising: a transmission control unit that adds a burst header detectable by a burst receiver provided in the upper optical transmission device to the continuous signal transmitted to the other upper optical transmission device. The optical transmission device described in. A plurality of high-order optical transmission devices as optical line termination devices that terminate signals transmitted to and received from an external device, and a plurality of optical line termination devices that become objects to the control entity In a configuration in which a lower optical transmission device is connected by an optical transmission path, communication with another upper optical transmission device is performed by transmitting a continuous signal and performing a burst signal transmission, and An optical transmission method by a higher-order optical transmission apparatus that performs communication,
The upper level optical transmission device is
When communication between the upper level optical transmission devices is performed between a plurality of upper level optical transmission devices, positions transmitted from the two or more other upper level optical transmission devices via the optical transmission path are different positions upon reception. Receiving and separating continuous signals of different wavelengths on which data are superimposed to be
And performing a bursting process of extracting only the data portion addressed to the upper-level optical transmission apparatus stored in each of the separated continuous signals.

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