JP2009246756A - Master station communication apparatus, slave station communication apparatus, and optical communication network system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To expand a bandwidth of a downlink signal in an optical communication network system to which a passive optical network (PON) is applied. <P>SOLUTION: The present invention relates to an optical communication network system wherein a PON is configured by connecting one or more slave station communication apparatuses to a master station communication apparatus. Then, the master station communication apparatus includes a means which sends out a downlink signal using an optical signal of a first wavelength and receives an uplink signal, sent from each of the slave station communication apparatuses, using an optical signal of a second wavelength; and a means comprising one or more increment downlink signal transmission sections each for sending out a downlink signal using an optical signal of any wavelength other than the first and second wavelengths. Furthermore, each of the slave station communication apparatuses includes a means for receiving a downlink signal using an optical signal of the first wavelength and transmits an uplink signal using an optical signal of the second wavelength, and a means comprising one or more increment downlink signal reception sections each for receiving a downlink signal using an optical signal of any wavelength other than the first and second wavelengths. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a master station communication device, a slave station communication device, and an optical communication network system, and can be applied to, for example, an optical communication network system to which a PON (Passive Optical Network) is applied.

  As a method for realizing an optical access network of subscribers by FTTx (Fiber To The Home / Curb / Node / Premises, etc.), there is a PON system. The PON system can hold a plurality of subscribers with a single interface on the subscriber terminal side, thereby reducing the number of expensive optical components on the station side, and is effective for reducing the cost of the network. Various methods have been standardized and applied as one of the subscriber access methods. Conventional PON systems include, for example, ATM (Asynchronous Transfer Mode) -PON, B (Broadband) -PON system (see Non-Patent Document 1), G (Gigabit-capable) -PON system (see Non-Patent Document 2), E (Ethernet (registered trademark))-PON system (IEEE802.3ah) and the like.

  FIG. 4 is an explanatory diagram showing the topology in a conventional PON.

  As shown in FIG. 4, in the conventional PON topology, an optical fiber extending from an optical subscriber terminal (hereinafter referred to as “OLT”) is branched by the number of accommodated subscribers in the splitter. To the optical line terminator (hereinafter referred to as “ONU”) in each subscriber's house through an optical fiber.

  Next, a signal transmission method between the optical subscriber terminal equipment (OLT) and the optical line terminal equipment (ONU) of each subscriber will be described. First, an optical signal used by a signal from the OLT to each ONU (hereinafter referred to as “downstream signal” or “DS”) and a signal from each ONU to the OLT (hereinafter referred to as “upstream signal” or “US”). Uses different wavelengths (wavelength λ1, wavelength λ2). As a result, each of the OLT and each ONU can extract only an optical signal having a necessary wavelength to be received, and thus can simultaneously communicate in both directions. Since the signal (DS) transmission method from the OLT to each ONU is one-to-many communication, the signal to each ONU is time-division multiplexed from the OLT side and transmitted in a broadcast format via the splitter. Each ONU is communicated by extracting and receiving only the signal addressed to itself by a technique such as encryption. On the other hand, since the signal (US) transmission method from each ONU to the OLT is many-to-one communication, communication by time division multiplexing is also performed. However, when each ONU transmits independently at this time, each ONU is transmitted in the splitter. Since the signals from the ONUs may collide with each other and cannot be transmitted correctly, the OLT instructs each ONU to transmit to the ONUs so that collision can be avoided. Each ONU transmits in accordance with this timing instruction, thereby realizing time division multiplex communication without causing the upstream signal to collide with the splitter. For this reason, the OLT checks the transmission delay of each ONU in advance, and based on this result, the OLT performs transmission timing control to each ONU capable of collision avoidance considering the transmission delay difference from each ONU to the splitter. Is possible. This transmission path delay measurement method for enabling collision avoidance is called a ranging method. Note that ranging refers to, for example, distance measurement between the OLT and the ONU based on the OLT-ONU-OLT optical round trip time.

  FIG. 5 is an explanatory diagram showing a method for superimposing a broadcast service in a network system using a conventional PON.

  For the access network using the PON system, a new service is provided to the optical fiber that is the access line while maintaining the use of the conventional PON system (E-PON, GE-PON, B-PON, G-PON, etc.). In the case of addition, as shown in FIG. 5, conventionally, the image RF signal is exclusively wavelength-multiplexed with the third wavelength (wavelength λ3).

In addition, as a network system using the conventional PON system, as in the apparatus described in Patent Document 1, the maximum bandwidth of the downlink signal transmitted from the OLT to the ONU is controlled according to the processing speed on the ONU side, Some use the downstream signal band efficiently.
ITU-T recommendation 983 ITU-T recommendation 984 JP 2007-049376 A

  However, service menus that use IP communication, which develops day by day, are steadily increasing. In particular, the demand for traffic of downstream signals tends to increase in the direction of squeezing the serviceable communication band.

  On the other hand, in the system shown in FIG. 5 described above, the added downlink signal is a service provision limited to broadcasting by a signal transmission method different from the communication signal, and is limited and independent from IP Internet communication. It was a service. In other words, when a new service is superimposed by wavelength multiplexing in a conventional PON network system, the service is provided only in the downlink direction using an RF signal different from the IP communication signal and contributes to the IP communication using GE-PON. It was not intended to expand the IP communication bandwidth. Further, even if the apparatus described in Patent Document 1 is applied and the downlink signal band can be used efficiently, the downlink signal band itself does not increase. There was a problem that I could not.

  Therefore, a master station communication device, a slave station communication device, and an optical communication network system that can expand the bandwidth of the downlink signal are desired.

  In the center system of the first aspect of the present invention, (1) one or more slave station communication devices are connected to the master station communication device, and the master station communication device and each slave station communication device constitute a PON. In the master station communication device in the optical communication network system, (2) using the optical signal of the first wavelength, the downlink signal is transmitted to each slave station communication device, and the slave station communication device Basic communication means for receiving the transmitted upstream signal using the optical signal of the second wavelength; and (3) each of the slave stations using an optical signal of a wavelength other than the first and second wavelengths. It is characterized by having an additional downlink signal transmission means having one or a plurality of additional downlink signal transmission units for transmitting a downlink signal to the communication device.

  In the terminal system of the second aspect of the present invention, (1) one or more slave station communication devices are connected to the master station communication device, and the master station communication device and each slave station communication device constitute a PON. (2) receiving a downstream signal using the optical signal of the first wavelength transmitted from the master station communication apparatus, and receiving the optical signal of the second wavelength. Using basic communication means for transmitting an upstream signal to the master station communication device, and (3) using an optical signal having a wavelength other than the first and second wavelengths transmitted from the master station communication device. And an additional downlink signal receiving means having one or a plurality of additional downlink signal receiving sections for receiving the received downlink signals.

  In the optical communication network system of the third aspect of the present invention, (1) one or more slave station communication devices are connected to a master station communication device, and the master station communication device and each slave station communication device are set to PON. In the configured optical communication network system, (2) the master station communication device of the first aspect of the present invention is applied as the master station communication device, and (3) the second book is used as each slave station communication device. The slave station communication device of the invention is applied.

  ADVANTAGE OF THE INVENTION According to this invention, the band of a downstream signal can be extended in the optical communication network system to which PON is applied.

(A) First Embodiment Hereinafter, a first embodiment of a master station communication device, a slave station communication device, and an optical communication network system according to the present invention will be described in detail with reference to the drawings. The master station communication device and the slave station communication device of the first embodiment are an OLT and an ONU, respectively.

(A-1) Configuration of the First Embodiment FIG. 1 is a block diagram showing a functional configuration of the optical communication network system 10 of the first embodiment.

  The optical communication network system 10 includes an OLT 20 and N ONUs 30 (30-1 to 30-N). In the first embodiment, the number of ONUs 30 is assumed to be N. However, the number may be one and the number is not limited. In the first embodiment, the ONUs 30-1 to 30-N are described as having the same configuration. However, ONUs having other configurations such as existing ONUs may be mixed. In the optical communication network system 10, the OLT 20 and the ONUs 30-1 to 30 -N are connected by a PON connection method by branching an optical fiber 40 with an optical splitter 50. In FIG. 1, one optical fiber connected to the OLT 20 is N-branched by the optical splitter 50 using the optical splitter 50, but may be branched using a plurality of optical splitters.

  Next, a detailed configuration of the OLT 20 will be described. The OLT 20 is connected to the ONUs 30-1 to 30-N and the higher level network, and connects the terminals under the ONUs 30-1 to 30-N to the higher level network. The OLT 20, the monitoring control unit 21, and the additional PONTC It includes a layer processing unit 23, a basic PONTC layer processing unit 22, an optical transceiver 24, an optical transponder unit 25, a switch (hereinafter referred to as “SW”) unit 26, and a physical (hereinafter referred to as “PHY”) layer unit 27. ing. The OLT 20 may be configured by a single device or may be configured by being divided into a plurality of devices or substrates, but can be functionally represented as shown in FIG.

  In the OLT 20, the basic PONTC layer processing unit 22 uses the first downlink signal (hereinafter referred to as “DS # 1”) and the uplink signal (hereinafter also referred to as “US”) to, for example, a TC (Transmission Convergence) layer. Communication control for such processing is performed. The basic PONTC layer processing unit 22 is connected to an optical fiber via an optical transceiver 24. Further, the basic PONTC layer processing unit 22 is connected to an upper network (device) via the SW unit 26 and the PHY layer unit 27.

  The extension PONTC layer processing unit 23 performs communication control such as processing related to the TC layer with respect to the second downlink signal (hereinafter referred to as “DS # 2”) in the OLT 20. The additional PONTC layer processing unit 23 is connected to the optical fiber via the optical transceiver 24 and the optical transponder unit 25.

  The extended PONTC layer processing unit 23 does not perform processing related to the uplink signal unlike the basic PONTC layer processing unit 22, and therefore, in this embodiment, only the configuration specialized for the downlink signal is provided and is related to reception of the uplink signal. Unnecessary functions are deleted and simplified. Note that the extension PONTC layer processing unit 23 may be configured to perform only the processing related to the downlink signal by using the same configuration as that of the extension PONTC layer processing unit 23.

  The optical transceiver 24 performs photoelectric conversion and frequency multiplexing on the signal transmitted and received by the basic PONTC layer processing unit 22, and transmits and receives optical signals to and from the ONUs 30-1 to 30 -N via the optical fiber 40. In the optical communication between the OLT 20 and the ONUs 30-1 to 30-N, the wavelength used for DS # 1 communication is “λ1”, the wavelength used for US communication is “λ2”, and is used for DS # 2 communication. The wavelength is different from “λ3”. In this way, in addition to the wavelength (λ1 / λ2) of the light used in DS # 1 / US, the wavelength used in DS # 2 is set to λ3, thereby doubling the communication band for downlink signals. It is said.

  The optical transponder unit 25 includes an electrical / optical converter (hereinafter referred to as “E / O”) 251, and a downlink signal (DS # 2) provided from the additional PONTC layer processing unit 23 by the E / O 251. Is converted from an electrical signal into an optical signal of λ3 and supplied to the optical transceiver 24. The E / O 251 may be realized using an existing photoelectric conversion element. The optical transponder unit 25 may be replaced with one having the same configuration as the optical transceiver 24 described later.

  Based on the control of the supervisory control unit 21, the SW unit 26 uses the basic PONTC layer processing unit 22 or the additional PONTC layer processing unit 23 to receive data (frames) given from the upper network through the PHY layer unit 27. Give it to one of them. The SW unit 26 transmits the data (frame) given from the basic PONTC layer processing unit 22 or the additional PONTC layer processing unit 23 to the upper network via the PHY layer unit 27.

  The supervisory control unit 21 controls the SW unit 26 as to whether the data (frame) that has reached the SW unit 26 from the higher-level network is distributed to the basic PONTC layer processing unit 22 or the additional PONTC layer processing unit 23 To do. In addition, when the OLT 20 includes a plurality of additional PONTC layer processing units 23, the monitoring control unit 21 may control which of the additional PONTC layer processing units 23 is allocated the arrived data (frame). .

  For example, the monitoring control unit 21 may perform control so as to determine a distribution destination according to the type of the arrived frame. As a method for determining the type of the arrived frame, for example, the determination may be made based on the header information of the frame. For example, if the arrived frame is an IP retransmission service for terrestrial digital broadcast content that requires a downlink traffic band, the frame is distributed to the SW unit 26 to the additional PONTC layer processing unit 23. You may control.

  The optical transceiver 24 includes an optical / electrical converter (hereinafter referred to as “O / E”) 241, an E / O 242, and a wavelength division multiplexing filter (hereinafter referred to as “WDM”) 243. The O / E 241, the E / O 242, and the WDM 243 do not have to be integrated devices as the optical transceiver 24, and may be separate devices.

  The O / E 241 converts the upstream signal (US) given through the WDM 243 from an optical signal having a wavelength of λ2 into an electrical signal and gives it to the basic PONTC layer processing unit 22. The E / O 242 converts the downstream signal (DS # 1) given from the basic PONTC layer processing unit 22 from an electrical signal to an optical signal having a wavelength of λ1, and gives it to the WDM 243. O / E 241 and E / O 242 may be realized by using existing photoelectric conversion elements.

  The WDM 243 is a wavelength division multiplexing filter (WDM filter) that branches and mixes optical signals having a plurality of wavelengths. In FIG. 1, the WDM 243 causes communication between the OLT 20 and the ONUs 30-1 to 30-N via the optical fiber 40 by branching and mixing optical signals having three wavelengths λ1, λ2, and λ3. Is. The WDM 243 mixes the optical signals having the wavelengths λ1 and λ3 from the E / O 242 and the optical transponder unit 25, and sends them to the optical fiber 40. Further, an optical signal having a wavelength of λ2 given through the optical fiber 40 is extracted from the ONUs 30-1 to 30-N, and given to the O / E 241. In FIG. 1, the WDM 243 is described as one that splits and mixes optical signals of three wavelengths, but the corresponding wavelengths and the number of signals are not limited.

  Next, the detailed configuration of the ONUs 30-1 to 30-N will be described. Each of the ONUs 30-1 to 30-N includes a monitoring control unit 31 (31-1 to 31-N), a basic PONTC layer processing unit 32 (32-1 to 32-N), and an additional PONTC layer processing unit 33 (33- 1-33), optical transceiver 34 (34-1 to 33-N), optical receiver 35 (35-1 to 35-N), SW unit 36 (36-1 to 36-N), PHY layer unit 37 (37-1 to 37-N). The ONU 30 may be configured by a single device or a plurality of devices, but can be functionally represented as shown in FIG.

  The basic PONTC layer processing unit 32 performs communication control such as processing related to the TC layer for the DS # 1 downlink signal and the uplink signal (US) in the ONU 30. The basic PONTC layer processing unit 32 is connected to the optical fiber 40 via the optical transceiver 34. The basic PONTC layer processing unit 22 is connected to a lower network (device) via the SW unit 36 and the PHY layer unit 37.

  The extension PONTC layer processing unit 33 performs communication control such as processing related to the TC layer for the DS # 2 downlink signal in the ONU 30. The additional PONTC layer processing unit 33 is connected to the optical fiber 40 via the optical transceiver 34 and the optical receiver 35.

  The extension PONTC layer processing unit 33 does not perform processing related to the uplink signal, but performs only processing related to the downlink signal, as in the case of the extension PONTC layer processing unit 23, and has only a configuration specialized for the downlink signal. Unnecessary functions related to transmission are deleted and simplified. Note that the additional PONTC layer processing unit 33 may be configured to perform only the processing related to the downlink signal by using the same configuration as the basic PONTC layer processing unit 32.

  The optical transceiver 34 performs photoelectric conversion and frequency multiplexing on the signal transmitted / received by the basic PONTC layer processing unit 32, and transmits / receives an optical signal to / from the OLT 20 via the optical fiber 40.

  The optical receivers 35-1 to 35 -N have O / E 351 (351-1 to 351 -N), respectively, and the downstream signal (DS # 2) given from the optical transceiver 24 by the O / E 351 is received. , Converted from an optical signal having a wavelength of λ3 to an electrical signal and supplied to the additional PONTC layer processing unit 23. The O / E 351 may be realized using an existing photoelectric conversion element. The optical transponder unit 25 may be replaced with one having the same configuration as the optical transceiver 24 described later.

  The SW unit 36 provides the basic PONTC layer processing unit 32 with data (frames) supplied from the lower network through the PHY layer unit 37. Further, the SW unit 36 transmits the data given from the basic PONTC layer processing unit 32 or the additional PONTC layer processing unit 33 to the lower network (device) via the PHY layer unit 37.

  The monitoring control unit 31 monitors and controls data (frames) that reaches the SW unit 36 from the lower network.

  The optical transceivers 34 (34-1 to 33-N) in the ONUs 30-1 to 30-N are respectively O / E341 (3411-1 to 341-N) and E / O342 (3422-1 to 342-). N) and WDM 343 (343-1 to 343-N). The O / E 341, the E / O 342, and the WDM 343 do not have to be integrated devices as the optical transceiver 34, and may be separate devices (elements).

  The O / E 341 converts the downstream signal (DS # 1) given via the WDM 343 from an optical signal having a wavelength of λ1 into an electrical signal and gives it to the basic PONTC layer processing unit 32. The E / O 342 converts the upstream signal (US) given from the basic PONTC layer processing unit 32 from an electrical signal to an optical signal having a wavelength of λ2, and gives it to the WDM 343. O / E341 and E / O342 may be realized by using existing photoelectric conversion elements.

  Similar to the WDM 243, the WDM 343 is a wavelength division multiplex filter (WDM filter) that branches and mixes optical signals having a plurality of wavelengths. In FIG. 1, when an optical signal (DS # 1, DS # 2) having a wavelength of λ1, λ3 is given from the OLT 20 via the optical fiber 40, the WDM 343 extracts an optical signal of each wavelength, An optical signal (DS # 1) having a wavelength of λ1 is applied to the O / E 341, and an optical signal (DS # 2) having a wavelength of λ3 is applied to the optical receiver 35. In addition, when an uplink signal (US) using λ2 is given from the E / O 342, the WDM 343 sends the optical signal to the optical fiber 40. In FIG. 1, the WDM 343 is described as one that splits and mixes optical signals of three wavelengths, but the corresponding wavelengths and the number of signals are not limited.

  Next, communication control between the OLT 20 and the ONU 30 will be described. In the conventional OLT and ONU, for example, a signal for confirming the activation status of the opposite network device (hereinafter referred to as “LinkUp”) and a signal related to communication control such as transmission request information are exchanged with each other before starting communication. , Downlink signal transmission control such as DBA (Dynamic Bandwidth Allocation) function is performed. On the other hand, in the optical communication network system 10, there is DS # 1 (downlink signal) and US (uplink signal) communication between the basic PONTC layer processing unit 22 of the OLT 20 and the basic PONTC layer processing unit 32 of the ONU 30. Therefore, communication control signals can be exchanged with each other, but communication between the additional PONTC layer processing unit 23 of the OLT 20 and the additional PONTC layer processing unit 33 of the ONU 30 is performed only with DS # 2 (downlink signal). Since communication is possible only through traffic, the communication control signal transmitted from the ONU 30 to the OLT 20 may be routed through the monitoring control units 21 and 31. That is, a communication control signal from the OLT 20 (extended PONTC layer processing unit 23) to the ONU 30 (extended PONTC layer processing unit 33) is transmitted using DS # 2. A communication control signal from the ONU 30 (extended PONTC layer processing unit 33) to the OLT 20 (extended PONTC layer processing unit 23) is given to the basic PONTC layer processing unit 32 via the monitoring control unit 31, and the basic PONTC layer processing unit 32 may be provided to the basic PONTC layer processing unit 22 using the US, and may further be provided to the additional PONTC layer processing unit 23 via the monitoring control unit 21. Note that data transmission / reception between the basic PONTC layer processing units 22 and 32 and the additional PONTC layer processing units 23 and 33 may be performed via the SW units 26 and 36 instead of the monitoring control units 21 and 31. Alternatively, direct transmission / reception may be performed.

  Next, the extension of the downlink signal in the optical communication network system 10 will be described. In the above description, in the optical communication network system 10, optical signals having two wavelengths λ 1 and λ 3 are used as downlink signals. However, the optical signals may be further expanded to use optical signals having three or more wavelengths. good.

  Hereinafter, as an example, a case where an optical signal having a wavelength of λ4 is further extended to the downstream signal will be described. In this case, an additional PONTC layer processing unit 23 and an optical transponder unit 25 having the same configuration are provided on the OLT 20 side, and an additional PONTC layer processing unit 33 is also provided on the ONU 30 side. You may implement | achieve by providing one set which has the structure similar to the optical receiver 35 further. In this case, for the WDMs 243 and 343, in addition to λ1, λ2, and λ3, it is assumed that the optical signal can be branched and mixed using λ4 as a downstream signal. As described above, in the OLT 20 and the ONU 30, the communication band that can be used for the downlink signal can be expanded by adding only the components related to the downlink signal communication.

(A-2) Operation of the First Embodiment Next, the operation of the network system 10 of the first embodiment having the above configuration will be described. First, operations related to downlink signals (DS # 1, DS # 2) will be described, and then operations related to uplink signals (US) will be described.

(A-2-1) Downlink signal (DS # 1, DS # 2)
Hereinafter, operations related to downlink signals (DS # 1, DS # 2) will be described. First, when a frame is given to the OLT 20 from an upper network (device), the frame is received by the PHY layer unit 27 and reaches the SW unit 26. Then, in the SW unit 26, it is distributed and given to either the basic PONTC layer processing unit 22 or the additional PONTC layer processing unit 23 under the control of the monitoring control unit 21.

  Next, the frame given from the SW unit 26 to the basic PONTC layer processing unit 22 is converted by the E / O 242 into an optical signal (DS # 1) using a wavelength of λ1, and the optical fiber 40 is transmitted via the WDM 243. Is sent out. The frame given from the SW unit 26 to the additional PONTC layer processing unit 23 is converted into an optical signal (DS # 2) using the wavelength of λ3 by the optical transponder unit 25, and the optical fiber 40 is transmitted via the WDM 243. Is sent out.

  Next, when an optical signal is given from the OLT 20 (WDM 243) to the WDM 343 via the optical fiber 40, the signal (DS # 1) using the wavelength of λ1 is converted into an electric signal by the O / E 341. To the basic PONTC layer processing unit 32. Further, the signal (DS # 2) using the wavelength of λ2 is converted into an electric signal by the optical receiver 35 and is given to the additional PONTC layer processing unit 33.

  Next, the frame reached by the DS # 1 signal given from the O / E 341 to the basic PONTC layer processing unit 32, and the DS # 2 signal given from the optical receiver 35 to the additional PONTC layer processing unit 33 The frame reached by the above is given to the lower network (device) via the SW unit 36 and the PHY layer unit 37.

(A-2-2) Uplink signal (UA)
Hereinafter, operations related to the uplink signal (UA) will be described. First, when a frame is given to the ONU 30 from the lower network (device), the frame is received by the PHY layer unit 37 and reaches the SW unit 36. Then, the frame is given from the SW unit 36 to the basic PONTC layer processing unit 22.

  Next, the frame given from the SW unit 36 to the basic PONTC layer processing unit 32 is converted into an optical signal (UA) using a wavelength of λ2 by the E / O 342 and sent to the optical fiber 40 via the WDM 343. Is done.

  Next, when an optical signal is given from the ONU 30 (WDM 343) through the optical fiber 40 to the OLT 20 (WDM 243), the upstream signal (UA) using the wavelength of λ2 is converted into an electrical signal by the O / E 241. Then, it is given to the basic PONTC layer processing unit 22.

  Next, the frame arrived from the O / E 241 by the UA signal given to the basic PONTC layer processing unit 22 is given to the upper network (device) via the SW unit 26 and the PHY layer unit 27.

(A-3) Effects of First Embodiment According to the first embodiment, the following effects can be achieved.

  In the OLT 20 and the ONU 30, by providing components (basic PONTC layer processing units 22 and 32, an optical transponder unit 25, and an optical receiver 35) only for extending the downstream signal, it is only necessary to add that portion. The bandwidth of the downstream signal can be expanded. In a conventional apparatus using GE-PON or the like, it is not possible to expand only a downlink signal for IP communication, and it is necessary to add a configuration related to the downlink signal and the uplink signal as a set. In the optical communication network system 10, since only the components related to the downlink signal can be added as described above, it is possible to reduce the cost when adding compared to the conventional one. In particular, in the OLT 20, when the signal (DS # 2) output from the additional PONTC layer processing unit 33 is converted into an optical signal having a wavelength of λ3, an optical transponder that is realized at a lower cost rather than an optical transceiver. Part 25 can be applied. Similarly, the ONU 30 can reduce the cost by applying the optical receiver 35 to convert the optical signal of λ3 into an electrical signal.

  In addition, since the OLT 20 and the ONU 30 can be constructed using technologies such as components applied to the existing GE-PON, they are realized using technologies that have been commercialized and ensure high reliability. In addition, the construction cost can be reduced.

  Further, the monitoring control unit 21 determines whether to use DS # 1 (λ1) or DS # 2 (λ3) for transmission according to the type of the frame that has reached the SW unit 26. There is an effect that congestion can be prevented and communication quality (Quality of Service; QoS) can be secured. For example, when a large downstream traffic band is required, such as an IP retransmission service for terrestrial digital broadcasting content, the downstream traffic is distributed to the DS # 2 (λ3) side, and other traffic (for example, IP phone) , HTTP, etc.) are assigned to DS # 1 (λ1), so that quality (QoS) can be ensured.

  In the operation between the basic PONTC layer processing unit 22 and the additional PONTC layer processing unit 23 in the OLT 20 and the operation between the basic PONTC layer processing unit 32 and the additional PONTC layer processing unit 33 in the ONU 30, the above-described communication control is performed. It is not necessary to perform complicated exchanges only by transferring such signals, and the extension PONTC layer processing units 23 and 33 do not need to be controlled according to the upstream signal, so the ONU 30 (extension PONTC layer processing unit 33). The service can be started by confirming the LinkUp.

(B) Second Embodiment Hereinafter, a second embodiment of a master station communication device, a slave station communication device, and an optical communication network system according to the present invention will be described in detail with reference to the drawings. The master station communication device and the slave station communication device of the second embodiment are an OLT and an ONU, respectively.

  FIG. 2 is a block diagram showing the overall configuration of the optical communication network system 10A of the second embodiment.

  FIG. 3 is an explanatory diagram showing a case where a component related to downlink signal communication is realized as a separate device in the optical communication network system 10A of the second embodiment.

  In the first embodiment, the functional configurations of the optical communication network system 10A and the ONU 30 in the optical communication network system 10 have been described. However, as described above, only the components related to downlink signal communication are added to the OLT 20 and the ONU 30. By doing so, the communication band which can be used for a downlink signal can be expanded. As for the OLT 20 and the ONU 30, all the configurations may be configured on the same board or the same device. However, in order to facilitate the addition of only the components related to the downlink signal communication, the OLT 20 and the ONU 30 are used for the downlink signal communication. Such a component may be constructed as a separate substrate or a separate device. In the optical communication network system 10A according to the second embodiment, the components related to downlink signal communication are constructed as separate boards or separate devices. Hereinafter, only the difference from the first embodiment will be described for the optical communication network system 10A of the second embodiment.

  The optical communication network system 10A includes an OLT 20A and an ONU 30A (30A-1 to 30A-N).

  The OLT 20A includes a monitoring control unit 21, a basic OLT unit 201, an additional OLT unit 202, and a WDM 28. In the second embodiment, it is assumed that the monitoring control unit 21, the basic OLT unit 201, the additional OLT unit 202, and the WDM 28 are constructed as separate boards (separate modules) or separate devices (separate units). Note that the monitoring control unit 21 is the same as that of the first embodiment, and a description thereof will be omitted. In this embodiment, the SW unit 26 is described as being constructed as a device different from the OLT 20A. However, similar to the monitoring control unit 21, the SW unit 26 may be constructed on the OLT 20A. .

  The basic OLT unit 201 is a basic component in the OLT 20A, that is, as an element necessary for communication with the ONUs 30A-1 to 30A-N using λ1 and λ2, as an additional PONTC layer processing unit 23, optical It has a transceiver 24 and a PHY layer portion 271. Since the additional PONTC layer processing unit 23 and the optical transceiver 24 are the same as those in the first embodiment, detailed description thereof is omitted.

  The PHY layer unit 271 has a function of an interface for communicating with the SW unit 26. The PHY layer unit 271 provides data provided from the SW unit 26 to the basic PONTC layer processing unit 22, and is provided from the basic PONTC layer processing unit 22. Data is supplied to the SW unit 26.

  The extension OLT unit 202 includes an extension PONTC layer processing unit 23, a PHY layer unit 272, and an optical transponder unit 25 as a configuration for extending the communication band of the downlink signal in the OLT 20A. The additional PONTC layer processing unit 23 and the optical transponder unit 25 are the same as those in the first embodiment, and thus detailed description thereof is omitted.

  The PHY layer unit 272 has a function of an interface for causing the additional PONTC layer processing unit 23 to communicate with the SW unit 26, and provides data provided from the SW unit 26 to the additional PONTC layer processing unit 23. is there.

  The WDM 28 is a WDM filter that branches and mixes optical signals having a plurality of wavelengths. In FIG. 2, the WDM 28 branches and mixes optical signals of three wavelengths λ1, λ2, and λ3, thereby allowing the basic OLT unit 201, the additional OLT unit 202, and the ONUs 30-1 to 30-1 through the optical fiber 40. Communication with 30-N is performed. When the WDM 28 receives optical signals of wavelengths λ 1 and λ 3 from the optical transceiver 24 (WDM 243) of the basic OLT unit 201 and the optical transponder unit 25 (E / O 251) of the additional OLT unit 202, the WDM 28 mixes the optical signals. Send to fiber 40. Further, an optical signal having a wavelength of λ2 given through the optical fiber 40 is extracted from the ONUs 30A-1 to 30A-N, and given to the optical transceiver 24 (WDM 243) of the basic OLT unit 201. In FIG. 2, the WDM 28 is described as branching and mixing optical signals of three wavelengths, but the corresponding wavelengths and the number of signals are not limited. In FIG. 2, since the basic OLT unit 201 and the additional OLT unit 202 are constructed as separate boards or separate devices, the WDM 28 is provided. However, as in the first embodiment (FIG. 1), an optical transceiver is provided. In the case of branching / mixing with only 24 (WDM 243), the WDM 28 may be omitted.

  The ONU 30A includes a monitoring control unit 31 (31-1 to 31-N), a SW unit 36 (36-1 to 36-N), a basic ONU unit 301 (301-1 to 301-N), and an additional ONU unit 302, respectively. (302-1 to 302-N) and WDM38 (301-1 to 301-N). In the second embodiment, the monitoring control unit 31, the SW unit 36, the basic ONU unit 301, and the additional ONU unit 302 are each constructed as a separate board (separate module) or a separate device (separate unit). To do.

  Note that the monitoring control unit 31 is the same as that of the first embodiment because the SW unit 36 is the same as that of the first embodiment, and detailed description thereof will be omitted. However, as shown in FIG. The control device 39 (302-1 to 302-N) may be constructed.

  The basic ONU unit 301 includes an additional PONTC layer processing unit 33, an optical transceiver 34, and a PHY layer unit 371 as basic components in the ONU 30A. Since the additional PONTC layer processing unit 33 and the optical transceiver 34 are the same as those in the first embodiment, detailed description thereof is omitted.

  The PHY layer unit 371 has a function of an interface for the basic PONTC layer processing unit 32 to communicate with the SW unit 36, and provides the basic PONTC layer processing unit 32 with data provided from the SW unit 36, The data given from the layer processing unit 32 is given to the SW unit 36.

  The extension ONU unit 302 includes an extension PONTC layer processing unit 33, a PHY layer unit 372, and an optical receiver 35 as components for extending the communication band for downlink signals in the ONU 30A. Since the additional PONTC layer processing unit 33 and the optical receiver 35 are the same as those in the first embodiment, detailed description thereof is omitted. The PHY layer unit 372 functions as an interface for the extension PONTC layer processing unit 33 to communicate with the SW unit 36, and provides the SW unit 36 with data given from the extension PONTC layer processing unit 33. is there.

  The WDM 38 is a WDM filter that branches and mixes optical signals having a plurality of wavelengths. In FIG. 2, the WDM 38 divides and mixes optical signals of three wavelengths λ1, λ2, and λ3, thereby connecting the basic ONU unit 301, the additional ONU unit 302, and the OLT 20A via the optical fiber 40. Of communication. The WDM 38 extracts the downstream signals (DS # 1, DS # 2) with wavelengths of λ1 and λ3 given from the OLT 20A via the optical fiber 40, and the optical transceiver 34 (WDM 343) of the basic ONU unit 301. And provided to the optical transponder unit 35 (E / O 351) of the additional ONU unit 302. Also, an upstream signal (UA) having a wavelength of λ2 given from the optical transceiver 34 (WDM 343) of the basic ONU unit 301 is sent to the optical fiber 40. In FIG. 2, the WDM 38 is described as branching and mixing optical signals having three wavelengths, but the corresponding wavelengths and the number of signals are not limited. In FIG. 2, the basic ONU unit 301 and the additional ONU unit 302 are provided as WDMs 38 in order to construct them as separate boards or separate devices. However, as in the first embodiment (FIG. 1), the optical transceiver 34 ( When branching / mixing is performed by the WDM 343), the WDM 38 may be omitted.

  As described above, in the optical communication network system 10A, the extension OLT unit 202 and the extension ONU unit 302 are added to the OLT 20A and the ONU 30A, respectively, and an optical signal having a different wavelength is assigned to the added one, thereby down-signals. Can be extended.

  The operation of the optical communication network system 10A according to the second embodiment is the same as that of the first embodiment except that optical signals are transmitted and received between the OLT 20A and the ONUs 30A-1 to 30A-N via the WDMs 28 and 38. Since it is substantially the same as that of the embodiment, detailed description thereof is omitted.

  According to the second embodiment, in addition to the effects of the first embodiment, the following effects can also be achieved.

  According to the second embodiment, in the OLT 20A and the ONU 30A, the configuration required for the extension of the downlink signal is aggregated in the extension OLT unit 202 and the extension ONU unit 302, respectively, and is configured as a separate board or a separate device. Compared with the first embodiment, the downlink signal can be expanded more easily, and the cost required for extending the downlink signal can be reduced.

(D) Other Embodiments The present invention is not limited to the above-described embodiments, and may include modified embodiments as exemplified below.

(D-1) In each of the above embodiments, when the wavelength of the optical signal used for the downlink signal is increased on the OLT side, the extension is performed in the same manner on the ONU side. On the side, it is not necessary to correspond to the optical signals of all wavelengths added on the OLT side, and the wavelength corresponding to each ONU may be different. For example, when optical signals of four wavelengths of λ1, λ3, λ4, and λ5 are transmitted as downlink signals from the OLT side, so that optical signals of all four wavelengths can be received on each ONU side, It is not necessary to have an additional PONTC layer processing unit or an optical receiver. For example, one ONU corresponds to two wavelengths λ1 and λ3, and another ONU corresponds to λ1, λ4, and λ5. The corresponding wavelength may be different for each. When the wavelength corresponding to each ONU is different, for example, the monitoring control unit on the OLT side may sort which optical signal is transmitted for each destination of the arrived data (frame). .

It is the block diagram which showed the functional structure of the optical communication network system which concerns on 1st Embodiment. It is the block diagram which showed the structure of the optical communication network system which concerns on 2nd Embodiment. It is explanatory drawing shown about the case where the structure part which concerns on communication of a downlink signal is implement | achieved as another apparatus in the optical communication network system which concerns on 2nd Embodiment. It is explanatory drawing shown about the structure of the optical communication network system by the conventional PON. It is explanatory drawing shown about the structure at the time of superimposing a broadcast service in the optical communication network system by the conventional PON.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Optical communication network system, 20 ... OLT, 21 ... Supervisory control part, 22 ... Basic PONTC layer processing part, 23 ... Extension PONTC layer processing part, 24 ... Optical transceiver, 241 ... O / E, 242 ... E / O, 243 ... WDM, 25 ... optical transponder unit, 26 ... SW unit, 27 ... PHY layer unit, 30, 30-1 to 30-N ... ONU, 31, 31-1 to 31-N ... monitoring control unit, 32, 32 -1 to 32-N: basic PONTC layer processing unit, 33, 33-1 to 33-N, additional PONTC layer processing unit, 34, 34-1 to 33-N, optical transceiver, 341, 341-1 to 341- N ... O / E, 342, 342-1 to 342-N ... E / O, 343, 343-1 to 343-N ... WDM, 35, 35-1 to 35-N ... optical receiver, 351, 351-1 ~ 51-N ... O / E, 36,36-1~36-N ... SW part, 37,37-1~37-N ... PHY layer unit, 40 ... optical fiber, 50 ... optical splitter.

Claims (7)

In the master station communication device in the optical communication network system in which one or a plurality of slave station communication devices are connected to the master station communication device, and the master station communication device and each slave station communication device constitute a PON ,
Using the optical signal of the first wavelength, the downstream signal is transmitted to each of the slave station communication devices, and the upstream signal using the optical signal of the second wavelength transmitted from each of the slave station communication devices is transmitted. Receiving basic communication means; and
Using an optical signal having a wavelength other than the first and second wavelengths, and an additional downlink signal transmitting unit having one or a plurality of additional downlink signal transmitters for transmitting a downlink signal to each of the slave station communication devices. A master station communication device comprising:   When the master station communication device intends to send transmission data to each of the slave station communication devices using a downlink signal, it is distributed to either the basic communication means or the additional downlink signal transmission means. The master station communication device according to claim 1, further comprising means.   In the case where the extension downlink signal transmission means has a plurality of extension downlink signal transmission units, the distribution means includes any one of the extension downlink signal transmission units when transmitting the transmission data using the extension downlink signal transmission unit. 3. The master station communication device according to claim 2, wherein the master station communication device is assigned to each other and transmitted.   4. The master station communication device according to claim 2, wherein the distribution unit distributes the transmission data according to a type of the transmission data.   When a communication control signal related to downlink signal communication control by the additional downlink signal transmission means is given from each slave station communication device to the basic communication means using the optical signal of the second wavelength, the communication control signal is transmitted. 5. The master station communication device according to claim 1, further comprising communication control signal transmission means for giving a signal to the additional downlink signal transmission means. In the slave station communication device in the optical communication network system in which one or a plurality of slave station communication devices are connected to the master station communication device, and the master station communication device and each slave station communication device constitute a PON ,
Basics for receiving a downlink signal using an optical signal of the first wavelength transmitted from the master station communication device and transmitting an uplink signal to the master station communication device using an optical signal of the second wavelength Communication means;
An additional downlink signal receiving means having one or a plurality of additional downlink signal receiving sections for receiving a downlink signal using an optical signal having a wavelength other than the first and second wavelengths transmitted from the master station communication device; A slave station communication device comprising: In the optical communication network system in which one or more slave station communication devices are connected to the master station communication device, and the master station communication device and each of the slave station communication devices constitute a PON,
While applying the parent station communication device according to claim 1 as the parent station communication device,
An optical communication network system, wherein the slave station communication device according to claim 6 is applied as each of the slave station communication devices.

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