JP5942751B2 - Station side apparatus and optical communication network system for WDM / TDM-PON system - Google Patents

Description

  The present invention relates to an optical communication network system using a WDM (Wavelength Division Multiplexing) / TDM (Time Division Multiplexing) -PON (Passive Optical Network) system and a station side apparatus thereof.

  As one form of the optical access network, there is a passive optical network (PON: Passive Optical Network). The PON uses a single station side device (OLT) provided in the station and a plurality of subscriber side devices (ONU: Optical Network Unit) provided in the subscriber's home via an optical fiber and an optical splitter. Connect.

  In PON, different signals are assigned to signals transmitted from each ONU to the OLT (hereinafter referred to as upstream optical signal) and signals transmitted from the OLT to each ONU (hereinafter referred to as downstream optical signal) in order to prevent interference. In PON, various multiplexing techniques are used. The multiplexing technology used in the PON includes time division multiplexing (TDM) technology in which a short interval on the time axis is assigned to each subscriber, wavelength division multiplexing (WDM) in which different wavelengths are assigned to each subscriber (WDM: Wave Division Division Multiplex). And code division multiplexing (CDM) technology that assigns different codes to each subscriber. Among these multiplexing techniques, TDM-PON using TDM is currently most widely used.

  In TDM-PON, the OLT manages the transmission timing of each ONU and uses TDMA (Time Division Multiple Access) technology that controls upstream optical signals from different ONUs so as not to collide with each other.

  Among the PON systems, those using the Ethernet (registered trademark) technology are referred to as Ethernet (registered trademark) -PON, and those using the Gigabit Ethernet (registered trademark) technology are referred to as GE-PON. GE-PON is standardized by IEEE 802.3ah. Furthermore, 10G-EPON, which is 10 times faster in data rate, is standardized by IEEE 802.3av.

  In the GE-PON system, one OLT manages one PON branch including a branched optical transmission line and an ONU connected to a branch destination of the optical transmission line. Here, for example, when the number of ONUs included in one PON branch is small, it is expensive to share the OLT with a small number of ONUs. Therefore, when there are few ONUs in the PON branch, it is desirable that one OLT manages a plurality of PON branches. For this purpose, a PON system (hereinafter also referred to as TDM / WDM-PON) that enables management of a plurality of PON branches by one OLT by using both TDM and WDM has been proposed.

  In TDM / WDM-PON, an optical routing function is newly added. The use of an AWG (arrayed wavelength grating) router is considered as a device for realizing optical routing by wavelength. In the TDM / WDM-PON configured as described above, one OLT can send a downstream optical signal to different PON branches by changing the transmission wavelength of the downstream optical signal. The ONU can send an upstream optical signal to a specific OLT by sending an upstream optical signal having a wavelength designated by the OLT. As a result, the connection between the OLT and the ONU can be freely configured regardless of the PON branch.

JP 2010-103893 A JP 2011-4270 A

  In order to communicate between the OLT and the ONU, the OLT needs to recognize the ONU connected to the optical fiber. For this purpose, the OLT registers the ONU in advance. The 10G-EPON defines that a discovery process is performed to register an unregistered ONU in the OLT. In this discovery process, an unregistered ONU waits until the OLT can receive a discovery gate message that is transmitted as a frame at regular intervals, and after receiving the discovery gate message, returns a Register request to the OLT. This starts registration. For this reason, in the discovery process, it is important that the ONU can reliably receive the discovery gate message early.

  When applied to an optical communication network system using WDM / TDM-PON on the basis of this registration method, wavelength setting of a TF (Tunable Filter) in the ONU becomes a problem. The TF is provided to arbitrarily set the light reception wavelength of the ONU. In the WDM / TDM-PON, the wavelength of the discovery gate message arriving at the ONU differs depending on the OLT to be managed. Further, the unregistered ONU itself does not know at which wavelength the discovery gate message is transmitted. For this reason, for an unregistered ONU, for example, it is conceivable to use a method of waiting by sweeping the center wavelength of the TF as time passes, as in Patent Document 2. In this method, the discovery gate message can be received when the wavelength of the discovery gate message matches the center wavelength of the unregistered ONU TF. However, in this method, since registration is not started until the wavelength of the unregistered ONU TF matches the wavelength of the discovery gate message, the time until completion of ONU registration may increase. There is.

  Accordingly, an object of the present invention is to provide a station-side device and an optical communication network system that can quickly detect an unregistered subscriber-side terminal (ONU) by a discovery process in a WDM / TDM-PON optical communication network system. Is to provide.

The station-side apparatus of the present invention is a station-side apparatus having a plurality of external ports that can connect a plurality of subscriber-side terminals via a common optical transmission line in a WDM / TDM-PON optical network system, A plurality of optical transmission / reception units that are provided for the number of the plurality of external ports, transmit / receive optical signals using light emitting elements and light receiving elements, and each of which can adjust the transmission / reception wavelengths of the optical signals, and the number of the plurality of external ports A plurality of transmission / reception processing units provided to drive the light-emitting elements of each of the plurality of optical transmission / reception units to emit light according to transmission data and obtain reception data from output signals of the light-receiving elements of each of the plurality of optical transmission / reception units And a change-over switch that is arranged between the plurality of optical transmission / reception units and the plurality of transmission / reception processing units and switches electrical connection between the plurality of optical transmission / reception units and the plurality of transmission / reception processing units. An AWG router disposed between the optical signal transmission / reception terminal of each of the plurality of optical transmission / reception units and the plurality of external ports, the transmission / reception wavelength of the plurality of optical transmission / reception units, and the plurality of transmission / reception units Control means for controlling the processing operation of the processing section and the switching operation of the changeover switch circuit , wherein the control means performs a registration process for an unregistered subscriber-side terminal among the plurality of subscriber-side terminals. In the discovery mode, one of the plurality of transmission / reception processing units is selected to enable the one transmission / reception processing unit to perform the registration process, and the transmission / reception of the plurality of optical transmission / reception units is performed. The wavelength is controlled to a predetermined discovery wavelength, and the changeover switch circuit is connected between a transmission / reception terminal of the one transmission / reception processing unit and any one of the plurality of optical transmission / reception units. It is characterized in that to the gas connected.

An optical communication network system according to the present invention includes a WDM / having a plurality of subscriber-side terminals and a station-side device having a plurality of external ports that can connect the plurality of subscriber-side terminals via a common optical transmission line. In the TDM-PON type optical communication network system, the station side devices are provided by the number of the plurality of external ports, and transmit and receive optical signals by light emitting elements and light receiving elements. The plurality of optical transmission / reception units that are adjustable and the number of the plurality of external ports are provided, and the light emitting elements of each of the plurality of optical transmission / reception units are driven to emit light according to transmission data, and the plurality of optical transmission / reception units A plurality of transmission / reception processing units for obtaining received data from output signals of the light receiving elements, and the plurality of optical transmission / reception units disposed between the plurality of optical transmission / reception units and the plurality of transmission / reception processing units. A changeover switch circuit for switching electrical connection between the plurality of transmission / reception processing units, and an AWG router disposed between the transmission / reception terminals of the optical signals and the plurality of external ports of each of the plurality of optical transmission / reception units Control means for controlling the transmission / reception wavelengths of the plurality of optical transmission / reception units, processing operations of the plurality of transmission / reception processing units, and switching operation of the changeover switch circuit, and the control means includes the plurality of subscribers. In discovery mode in which registration processing is performed for an unregistered subscriber-side terminal among the side terminals, any one transmission / reception processing unit is selected from the plurality of transmission / reception processing units, and the registration is performed in the one transmission / reception processing unit. Enabling processing operation, controlling the transmission / reception wavelengths of the plurality of optical transmission / reception units to a predetermined discovery wavelength, and switching the switch circuit to the one transmission / reception processing unit. It is characterized in that electrically connecting between the receiving terminal and any one of the optical transceiver of the plurality of optical transceivers.

  In the station side apparatus and the optical communication network system of the present invention, an unregistered subscriber side terminal connected to the optical transmission line of the WDM / TDM-PON type optical communication network system receives at a predetermined discovery wavelength. If waiting, the optical signal for detecting the unregistered subscriber-side terminal transmitted from the station-side device can be received immediately, and the unregistered subscriber-side terminal is an unregistered subscriber-side terminal. By transmitting an optical signal for registration request to the station side device in response to the optical signal for detection, the station side device can start registration processing immediately according to the optical signal for registration request.

1 is a block diagram showing an optical communication network system to which the present invention is applied. It is a figure which shows the input / output characteristic of the AWG router of the station side apparatus in the system of FIG. It is a block diagram which shows the internal structure of ONU of the PON branch in the system of FIG. It is a sequence diagram in the discovery process of the system of FIG. FIG. 5 is a diagram illustrating signal paths of a changeover switch circuit and an AWG router in the discovery process of FIG. 4. FIG. 5 is a diagram illustrating signal paths of a changeover switch circuit and an AWG router in the discovery process of FIG. 4. It is a sequence diagram in other discovery processing of the system of FIG. It is a figure which shows the signal path | route of a changeover switch circuit and an AWG router in the discovery process of FIG.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 shows an optical communication network system of the present invention. The system comprises a terminal 1 equipped with the OLT 11 ₁ to 11 ₄ of four, the two ONU is provided per 1PON branch. The number of OLTs in the station side device 1 is not limited to four.

Station apparatus 1, in addition to the OLT 11 ₁ to 11 _4, and a switching circuit 12, the optical transceiver ₁₃ 1 _{to 13} 4, AWG router 14 and OLT controller 15,.

The changeover switch circuit 12 has 4 × 4 terminals corresponding to the four branches. The OLTs 11 _{1 to} 11 ₄ are connected to one of four terminals of the changeover switch circuit 12, and the optical transmission / reception units 13 _{1 to} 13 ₄ are connected to the other four terminals so as to be capable of bidirectional communication. The changeover switch circuit 12 can connect each of the OLTs 11 _{1 to} 11 ₄ to any _one of the optical transmission / reception units 13 _{1 to} 13 ₄ .

Although not shown, each of the optical transmission / reception units 13 _{1 to} 13 ₄ includes a wavelength tunable laser diode for optical transmission, a photodiode for optical reception, and a WDM filter. The emission wavelength (transmission wavelength) of the tunable laser diode and the reception wavelength (reception wavelength) of the photodiode can be adjusted to an arbitrary wavelength within a predetermined wavelength range. The WDM filter demultiplexes and combines the light reception signal and the light emission signal. Each of the optical transceivers 13 _{1 to} 13 ₄ is connected to _four internal ports 16 _{1 to} 16 ₄ of the AWG router 14.

Each of the OLTs 11 _{1 to} 11 ₄ drives the wavelength tunable laser diode via the changeover switch circuit 12 during transmission, and receives the output signal of the photodiode via the changeover switch circuit 12 during reception.

AWG router 14 is a 4 × 4 AWG router wavelength cyclic frequency, type 4 optical signal of the wavelength lambda ₁ to [lambda] ₄ different same wavelength spacing for each input port according to the routing table as shown in FIG. 2 with respect thereto An optical signal can be output from the output port. For example, when an optical signal having a wavelength λ ₁ is input to each of the input ports 1 to 4 (corresponding to the internal ports 16 _{1 to} 16 ₄ ), the optical signals are directly output to the corresponding output ports 1 to 4 (external ports 17 _{1 to} 17). ₄ ). When an optical signal with wavelength λ ₂ is input to input port 1, the optical signal is output from output port 2, and when an optical signal with wavelength λ ₃ is input to input port 1, the optical signal is output to output port 3. When an optical signal having a wavelength λ ₄ is input to the input port 1, the optical signal is output from the output port 4. Similarly, the other input ports 2 to 4 output an optical signal to the output port according to the wavelength. In addition, by using an AWG router having recurring properties, λ _{1 to} λ ₄ are used as downlink communication wavelengths, and circular wavelengths λ _{5 to} λ ₈ are used as uplink communication wavelengths, so that different wavelengths are used in the uplink and downlink. However, wavelength routing is performed with the same input / output port relationship between upstream and downstream.

Four external ports 17 _{1 to} 17 ₄ of the AWG router 14 are connected to each of the PON branches 2 ₁ to 2 _{4 through} optical fibers 20 _{1 to} 20 ₄ which are optical transmission lines.

OLT controller 15 performs OLT 11 ₁ to 11 ₄ each of the operation control of the transceiver, optical transceivers _131-134 each emission wavelength and the light receiving wavelength, and switching control of the switching circuit 12.

PON branches 21 _{to 24} has a plurality of ONU22 _1, 22 _2. In this embodiment, the PON branches 2 ₁ to 2 ₄ each have two ONUs 22 ₁ and 22 ₂ for easy understanding, but the number of ONUs is not limited.

The optical coupler 21 is connected to the optical fibers 20 _{1 to} 20 ₄ corresponding to the PON branches 2 ₁ to 2 ₄ , and is connected to the two ONUs 22 ₁ and 22 ₂ to demultiplex and multiplex the optical signals. That is, the optical coupler 21 demultiplexes the optical signal supplied from each of the optical fibers 20 _{1 to} 20 ₄ and supplies it to the ONUs 22 ₁ and 22 ₂ through the optical fibers 23 ₁ and 23 ₂ , and conversely, the ONUs 22 ₁ and 22. the optical signal supplied through the optical fiber ₂₃ 1, 23 ₂ from ₂ each synthesized and outputs corresponding to the optical fiber ₂₀ 1 to 20 _4. The upstream optical signal from each of the ONUs 22 ₁ and 22 ₂ is subjected to TDMA control.

As shown in FIG. 3, each of the ONUs 22 ₁ and 22 ₂ includes a WDM filter 31, an optical transmission unit 32, a TF (Tunable Filter) 33, an optical reception unit 34, a driver 35, a clock data recovery (CDR) 36, An ONU MAC-LSI 37 and a user network interface (UNI) 38 are provided. The WDM filter 31 demultiplexes the optical signal in the light receiving band from the optical signal supplied from the optical coupler 21 via the optical fiber 23 ₁ or 23 ₂ and supplies the demultiplexed optical signal to the TF 33. It is combined with the optical signal of the fiber 23 ₁ or 23 ₂ and supplied to the optical coupler 21. The optical transmission unit 32 is composed of a wavelength tunable laser diode for optical transmission, is optically connected to the WDM filter 31, and is electrically connected to the driver 35. The wavelength tunable laser diode for optical transmission is capable of adjusting the wavelength of the light emission signal within a predetermined wavelength range. The driver 35 drives the light transmission unit 32 to emit light according to the transmission data.

  The TF 33 is optically connected to the WDM filter 31 and extracts an optical signal having a specific wavelength among optical signals supplied from the WDM filter 31 as a received light signal. The optical receiver 34 is optically connected to the TF 33 and electrically connected to the CDR 36. The optical receiver 34 is a photodiode that converts a light reception signal supplied from the TF 33 into an electric signal. The CDR 36 extracts a clock signal for synchronization from the output electric signal of the optical receiver 34.

Each of the ONUs 22 ₁ and 22 ₂ includes an ONU MAC-LSI 37, which controls the wavelength of the light emission signal of the optical transmission unit 32 in accordance with an instruction signal from the OLT, and the TF 33 extracts it. The specific wavelength of the received light signal is controlled.

  The UNI 38 performs data format conversion to match the communication format on the user network (not shown) side.

Note that the OLTs 11 _{1 to} 11 ₄ , the changeover switch circuit 12, and the OLT controller 15 may be formed as one OLT chip.

Next, discovery processing in the optical communication network system having such a structure will be described with reference to the sequence diagram of FIG. Here, discovery processing is performed for each ONU in each of the PON branches 2 ₁ and 2 ₂ .

The overall management of the discovery process is executed by the OLT controller 15 of the station side device 1. First, OLT controller at the start of the discovery process 15 instructs the stop of the data transmission to all the OLT 11 ₁ to 11 ₄ (step S1). When each of the OLTs 11 _{1 to} 11 ₄ completes stopping the data transmission, the OLT controller 11 notifies the OLT controller 15 of the completion as a reply (step S2).

When the OLT controller 15 receives the notification of the completion of the data transmission stop, the OLT controller 15 designates the transmission / reception wavelength as λ ₁ (predetermined discovery wavelength) for each of the optical transmission / reception units 13 _{1 to} 13 ₄ (step S3). Thereby, the wavelength of the optical signal transmitted / received from each of the optical transmission / reception units 13 _{1 to} 13 _{4 in the} discovery process is set to λ ₁ . Further, the OLT controller 15 instructs the changeover switch circuit 12 to change the path (step S4). Switching circuit 12 is communicatively electrically connected bidirectionally to the OLT 11 ₁ and the light receiving unit 13 ₁ as shown by the solid line A1 in FIG. 5 in accordance with the path switching command.

OLT controller 15 performs the discovery instruction of the PON branches _{2 1} for OLT 11 ₁ (step S5). The discovery instruction includes number representing the PON branches _{2 1.} OLT 11 ₁ outputs a discovery driving signal is an electrical signal in response to the discovery instruction (step S6). Discovery driving signal is supplied to the variable-wavelength laser diode for optical transmission as described above of the optical transceiver 13 ₁ through the switch circuit. 12, a wavelength tunable laser diode for optical transmission is driven in response to the discovery drive signal wavelength It emits light at λ _1. Its wavelength lambda ₁ of the discovery Gate message is transmitted to the optical fiber 20 ₁ through between ports ₁₆ 1, 17 ₁ of AWG router 14 shown by the solid line A2 in FIG. 5, the discovery Gate message to the PON branches _{2 1} Is supplied (step S7). Also it allows receiving an optical signal response in Register request for discovery Gate message to open the discovery window light transceiver 13 ₁ in the light receiving wavelength as lambda _{5 (lambda 1} orbiting wavelength).

In PON branches _{2 1,} discovery Gate message light turnip 21, and is supplied to ONU22 ₁ via the optical cable 23 _1, also supplied to the ONU22 ₂ via the optical cable 23 _2. Here, if the ONU 22 ₁ is not registered, the ONU 22 ₁ is on standby for discovery processing with its TF 33 set to the wavelength λ ₁ . Therefore, in the ONU 22 ₁ , the discovery gate message as an optical signal is received by the optical receiver 34 via the WDM filter 31 and the TF 33. The optical receiver 34 converts the discovery gate message into an electrical signal. After the conversion, a synchronization clock is extracted by the CDR 36, and the clock and received data are supplied to the ONU MAC-LSI 37. The MAC-LSI 37 determines the type of received data. In the case of discovery Gate message, if the ONU itself not yet registered with the OLT, and supplies the transmission data of the Register request to send a Register request signal requesting registration to OLT 11 ₁ to the driver 35. Since driver 35 drives the optical transmitter 32 in accordance with the transmission data, the optical signal Register Request from the light transmitting unit 32 is sent toward the OLT 11 ₁ via the WDM filter 31 at a wavelength lambda _5. Optical signal Register request PON branches _{2 1} of the optical cable 23 ₁ and the optical coupler 21, and is transferred to the terminal 1 via the optical cable 20 ₁ (step S8).

In terminal 1, an optical signal of the Register request is supplied to the optical transceiver 13 ₁ through between ports ₁₇ 1, 16 ₁ of AWG router 14. Because are enabled to receive optical signals in the response at the Register request as described above in the optical transceiver 13 _1, the optical signal of the Register Request emitted from ONU22 ₁ is received. The optical transceiver unit 13 ₁ converts the optical signal of the Register request into an electric signal, the received data Register request is supplied to the OLT 11 ₁ having the discovery window of time zones through the switch circuit 12 (discovery window). By OLT 11 ₁ to Register request is supplied, the registration process is performed between the OLT 11 ₁ and ONU22 ₁ (step S10). Signal path between the OLT 11 ₁ and ONU22 ₁ in the registration process is the same as that of the discovery Gate messages and Register request.

When the OLT 11 ₁ completes the registration process, it notifies the OLT controller 15 of the completion of the discovery process for the ONU 22 ₁ (step S11). Incidentally, if ONU22 ₂ such ONU22 ₁ same PON branches _{2 1} and were unregistered ONU, so Register request is issued from ONU22 ₂ in another frame from the Register request from ONU22 ₁ that ONU22 registration process between the even OLT 11 ₁ and ONU22 ₂ from ₂ for ONU22 ₂ in accordance with the register request is executed.

Next, the OLT controller 15 instructs the changeover switch circuit 12 to switch paths (step S12). Switching circuit 12 is communicatively electrically connected bidirectionally to the OLT 11 ₁ and the light receiving unit 13 ₂ as shown with a solid line B1 in FIG. 6 according to the path switching instruction.

OLT controller 15 performs the discovery instruction of the PON branches _{2 2} relative to OLT 11 ₁ (step S13). The discovery instruction includes number representing the PON branches _{2 2.} OLT 11 ₁ outputs a discovery driving signal is an electrical signal in response to the discovery instruction (step S14). Discovery drive signal is supplied to the variable-wavelength laser diode for optical transmission as described above of the optical transceiver 13 ₂ through the switch circuit 12, a wavelength tunable laser diode for optical transmission is driven in response to the discovery drive signal wavelength It emits light at λ _1. The emission signal of wavelength lambda ₁ is transmitted through between ports ₁₆ 2, 17 ₂ of the AWG router 14 shown by the solid line B2 in FIG. 6 to the optical fiber 20 ₂ as discovery Gate message, the discovery Gate message PON branches 2 ₂ (step S15). Also it allows receiving an optical signal response in Register request for discovery Gate message to open the discovery window of the optical transceiver 13 ₂ in the light receiving wavelength as lambda _5.

In PON branches _{2 2,} discovery Gate message light turnip 21, and is supplied to ONU22 ₁ via the optical cable 23 _1, also supplied to the ONU22 ₂ via the optical cable 23 _2. Here, if the ONUs 22 ₁ and ONU 22 ₂ of the PON branch 2 ₂ are not registered, each of the ONUs 22 ₁₁ and ONU 22 ₂ is on standby for discovery processing with its TF 33 set to the wavelength λ ₁ . Therefore, in each of the ONU 22 ₁ and ONU 22 ₂ , the discovery gate message as an optical signal is received by the optical receiver 34 via the WDM filter 31 and the TF 33. Subsequent receiving operation is the same as the operation described in the PON branches 2 _1.

The same is true after the discovery gate message is received by the ONU MAC-LSI 37. Unregistered ONU supplies transmission data Register request to the driver 35 to send the Register request is a signal requesting registration to OLT 11 _1. Since driver 35 drives the optical transmitter 32 in accordance with the transmission data, the optical signal Register Request from the light transmitting unit 32 is sent toward the OLT 11 ₁ via the WDM filter 31 at a wavelength lambda _1. Optical signal Register request is forwarded to the optical line terminal 1 via the PON branches _{2 2} of the optical cable ₂₃ 1, 23 ₂ and the optical coupler 21 and optical cable 20 _2, (step S16).

In terminal 1, an optical signal of the Register request is supplied to the optical transceiver 13 ₂ through between ports ₁₇ 2, 16 ₂ of the AWG router 14. Because it is enabled to receive optical signals in the response at the Register request as described above in the optical transceiver 13 _2, ONU22 1, ONU22 optical signal Register request generated from the ₂ is received. The optical transceiver 13 ₂ converts the optical signal of the Register request into an electric signal, the received data Register request is supplied to the OLT 11 ₁ through the switch circuit 12. By OLT 11 ₁ to Register request is supplied, the registration process is performed between the ONU22 _1, ONU22 ₂ each OLT 11 ₁ and PON branch _{2 2} (step S18).

OLT 11 _1, upon completing ONU22 _1, ONU22 ₂ each registration PON branch _{2 2,} and reports the completion of the discovery process OLT controller 15. (Step S19).

Although not shown in the figure, the discovery process can be executed for the PON branches 2 ₃ and 2 ₄ in the same manner as the PON branch 2 ₁ or 2 ₂ described above.

In this way, in such a discovery process, each ONU sets and waits for a predetermined wavelength λ ₁ so that it can reliably receive the discovery gate message. Thereby, an unregistered ONU can start registration processing to OLT immediately. In addition, even if OLTs for a plurality of branches are provided, discovery processing can be executed for ONUs of all PON branches with one OLT, so that other OLTs in other sleep states (drive stop states) remain as they are. Can also be maintained. Therefore, it is possible to execute the discovery process while suppressing the power consumption of the station side device.

At the time of bandwidth upgrade, a plurality of ONUs in one PON branch are individually managed by a plurality of OLTs. For example, the transmission / reception wavelengths of the ONU 22 ₁ and ONU 22 ₂ are different from each other, for example, λ ₁ is assigned to the ONU 22 _1, and for example, λ ₂ is assigned to the ONU 22 ₂ . Thus, at the time of bandwidth upgrade, from the fairness of the allocated bandwidth, it is desirable that the OLT with the smaller number of management ONUs among the plurality of OLTs executes the discovery process of the PON branch. Further, when the OLT of sleep state described above for low power operation in the station side within the apparatus are present, OLT managing the PON branches on behalf of the OLT sleep state of the PON branches Discovery processing can be executed.

FIG. 7 shows a sequence diagram of another discovery process. In the discovery process of FIG. 7, OLT 11 ₁ is responsible for PON branch 2 ₁ , OLT 11 ₂ is responsible for PON branch 2 ₂ , OLT 11 ₃ is responsible for PON branch 2 ₃ , and OLT 11 ₄ is responsible for PON branch 2 ₄ . .

In the discovery process of Figure 7, terminal 1 of the OLT controller 15 first commands the stop of data transmission to all the OLT 11 ₁ to 11 ₄ (step S31). When each of the OLTs 11 _{1 to} 11 ₄ completes stopping the data transmission, the OLT controller 15 is notified of the completion as a reply (step S32).

When OLT controller 15 receives a notification of completion stop of the data transmission from the OLT 11 ₁ to 11 ₄ respectively, designating a transmission wavelength lambda ₁ with respect to the optical transceivers _131-134, respectively (step S33). As a result, the wavelength of the optical signal output from each of the optical transmission / reception units 13 _{1 to} 13 _{4 in the} discovery process is λ ₁ . Further, the OLT controller 15 instructs the changeover switch circuit 12 to change the path (step S34). The OLT 11 ₁ and the light receiving unit 13 ₁ as the switching circuit 12 is shown in solid lines C1~C4 8 in accordance with the route switching instruction, OLT 11 ₂ and the optical reception unit 13 _2, OLT 11 ₃ and the light receiving portion 13 ₃ , and the OLT 11 ₄ and the optical transmission / reception unit 13 ₄ are electrically connected to each other so as to be able to communicate individually in both directions.

OLT controller 15 performs the discovery instruction of the PON branches 21 _{to 24} to cope with OLT 11 ₁ to 11 ₄ (step S35). OLT 11 ₁ to 11 ₄ respectively in response to the discovery instruction outputs a discovery driving signal is an electrical signal (step S36). Discovery drive signals from each of the OLTs 11 _{1 to} 11 ₄ are supplied individually to the above-described wavelength tunable laser diodes for optical transmission of the optical transmission / reception units 13 _{1 to} 13 ₄ via the changeover switch circuit 12, respectively. tunable laser diode is driven to emit light at a wavelength lambda ₁ in response to the discovery drive signal. The emission signal of the wavelength λ ₁ is a discovery gate message between the ports 16 ₁ and 17 _1, between the ports 16 ₂ and 17 _{2 and} between the ports 16 ₃ and 17 _{3 of} the AWG router 14 indicated by solid lines D1 to D4 in FIG. The ports 16 ₄ and 17 ₄ are individually transmitted to the corresponding optical fibers 20 _{1 to} 20 ₄ respectively, and the discovery gate messages are respectively supplied to the PON branches 2 ₁ to 2 ₄ (step S37). In addition, each of the optical transmission / reception units 13 _{1 to} 13 ₄ enables reception of an optical signal in response to a Register request for a discovery gate message by opening a discovery window with a reception wavelength of λ ₅ .

In the PON branches 2 _{1 to} 2 ₄ , the discovery gate message is supplied to the ONU 22 ₁ via the optical cable 21 and the optical cable 23 ₁ , and also supplied to the ONU 22 ₂ via the optical cable 23 ₂ . Here, if the ONUs 22 ₁ and ONU 22 ₂ of the PON branch 2 ₂ are not registered, each of the ONUs 22 ₁₁ and ONU 22 ₂ is on standby for discovery processing with its TF 33 set to the wavelength λ ₁ . Therefore, in each of the ONU 22 ₁ and ONU 22 ₂ , the discovery gate message as an optical signal is received by the optical receiver 34 via the WDM filter 31 and the TF 33. The optical receiver 34 converts the discovery gate message into an electrical signal. The discovery gate message is clock extracted by the CDR, and the clock and received data are supplied to the ONU MAC-LSI 37. ONU for MAC-LSI 37 is supplied to the driver 35 to transmit data Register request for transmission to one of the corresponding OLT 11 ₁ to 11 ₄ of Register request in response to receiving data discovery Gate message. Since driver 35 drives the optical transmitter 32 in accordance with the transmission data, one of the optical transmitter 32 from the Register request optical signal wavelength lambda ₅ corresponding through the WDM filter 31 at OLT 11 ₁ to 11 ₄ Sent to one. The optical signal of the register request is transferred to the station side apparatus 1 via the optical cables 23 ₁ and 23 ₂ and the optical coupler 21 of each of the PON branches 2 ₁ to 2 ₄ and the optical cables 20 _{1 to} 20 ₄ (step S38). .

In terminal 1, between the ports ₁₇ 1, 16 ₁ of the optical signal each AWG router 14 of the Register request, port ₁₇ 2, 16 between _2, between the ports ₁₇ 3, 16 _3, between ports ₁₇ 4, 16 ₄ The signals are individually supplied to the optical transmission / reception units 13 _{1 to} 13 ₄ . Since the optical transmission / reception units 13 _{1 to} 13 ₄ can receive the optical signal in response to the register request as described above, the optical signals of the register request issued from the ONUs 22 ₁ and ONU 22 ₂ are received. When the optical transceiver _131-134 each of which receives an optical signal of Register request, converts it into an electric signal, the received data Register request is respectively supplied to OLT 11 ₁ to 11 ₄ via the changeover switch circuit 12 . By OLT 11 ₁ to 11 ₄ Register request to each of which is supplied, OLT 11 _one and PON registration process with the ONU22 _1, ONU22 ₂ each branch _{2 1} is performed, OLT 11 ₂ and PON ONU22 branch _{2 2 1} is registration processing executed between the ONU22 ₂ respectively, OLT 11 ₃ and registration process between the ONU22 _1, ONU22 ₂ each PON branch _{2 3} is executed, OLT 11 ₄ and ONU22 ₁ of PON branches _{2 4,} ONU22 Registration processing is executed between the _two (step S40).

OLT 11 ₁ to 11 ₄ each completes the ONU22 _1, ONU22 ₂ each registration of PON branches 21 _{to 24,} and reports the completion of the discovery process OLT controller 15 (step S41).

Thus, in the discovery process of Figure 7, since the stand-by setting TF to the wavelength lambda ₁ to a predetermined Multiple ONU, it is possible to reliably receive the discovery Gate message. In addition, since the discovery process is executed in parallel for each ONU of the PON branch to which a plurality of OLTs correspond, the registration process to the OLT can be completed quickly for unregistered ONUs.

  In addition, the discovery process of FIG. 7 is particularly suitable when it is executed at the initial stage after the system power is turned on. In such a case, there are many unregistered ONUs. Registration can be completed.

In the embodiment described above, although the lambda ₁ of the wavelength lambda ₁ to [lambda] ₄ using a wavelength for a given discovery in normal communication, the wavelength for a given discovery of wavelength lambda ₁ to [lambda] ₄ Other wavelengths may be used, and wavelengths other than the wavelengths λ _{1 to} λ ₄ may be used.

1 station side device 2 ₁ to 2 ₄ PON branch 11 _{1 to} 11 ₄ OLT
12 switch circuit 13 _{1 to} 13 ₄ optical transmitter / receiver 14 AWG router 15 OLT controller 21 optical coupler 22 ₁ , 22 ₂ ONU
31 WDM filter 32 Optical transmitter 33 TF
34 Optical receiver 35 Driver 36 CDR
37 ONU MAC-LSI
38 UNI

Claims (6)

In a WDM / TDM-PON type optical network system, a station side device having a plurality of external ports capable of connecting a plurality of subscriber side terminals via a common optical transmission line,
A plurality of optical transmission / reception units provided for the number of the plurality of external ports, transmitting / receiving optical signals by light emitting elements and light receiving elements, and the transmission / reception wavelengths of the optical signals being adjustable ,
Provided for the number of the plurality of external ports, drive the light emitting elements of each of the plurality of optical transmission / reception units according to transmission data, and receive from the output signals of the light receiving elements of each of the plurality of optical transmission / reception units A plurality of transmission / reception processing units for obtaining data;
A changeover switch circuit disposed between the plurality of optical transmission / reception units and the plurality of transmission / reception processing units, and for switching an electrical connection between the plurality of optical transmission / reception units and the plurality of transmission / reception processing units;
An AWG router disposed between the optical signal transmission / reception terminal of each of the plurality of optical transmission / reception units and the plurality of external ports;
Control means for controlling the transmission / reception wavelengths of the plurality of optical transmission / reception units, the processing operation of the plurality of transmission / reception processing units and the switching operation of the changeover switch circuit ,
The control means selects one transmission / reception processing unit from among the plurality of transmission / reception processing units in a discovery mode in which registration processing is performed for an unregistered subscriber-side terminal among the plurality of subscriber-side terminals. Enabling the one transmission / reception processing unit to perform the operation of the registration processing, controlling the transmission / reception wavelengths of the plurality of optical transmission / reception units to a predetermined discovery wavelength, and switching the switching circuit to the one transmission / reception processing unit. A station-side device characterized in that a transmission / reception terminal and any one of the plurality of optical transmission / reception units are electrically connected . In the discovery mode, the one transmission / reception processing unit supplies a discovery drive signal to the one optical transmission / reception unit via the changeover switch circuit in response to a discovery instruction from the control unit, and the one optical transmission / reception unit In response to a discovery drive signal, the optical signal for detecting a subscriber terminal is generated at the predetermined discovery wavelength and supplied to the AWG router via its transmission / reception terminal to detect the subscriber terminal. Transmitting the optical signal of any one of the plurality of external ports,
The one optical transceiver transmits the optical signal for registration request supplied from the outside to the one external port as a response signal to the transmitted optical signal for detecting the subscriber terminal. When receiving at the predetermined discovery wavelength via the transmission / reception terminal, the reception signal is supplied to the one transmission / reception processing unit via the changeover switch circuit, and the one transmission / reception processing unit responds to the reception signal. The station apparatus according to claim 1, wherein the registration process is executed . The unregistered subscriber terminal, when the unregistered state becomes a reception standby state at the predetermined discovery wavelength, receiving said optical signal for the subscriber terminal detection, the said optical signals for the registration request The station apparatus according to claim 2 , wherein the station apparatus transmits to the station apparatus at a predetermined discovery wavelength . The predetermined discovery wavelength is different between the downstream optical signal from the station side device to the subscriber side terminal and the upstream optical signal from the subscriber side terminal to the station side device. The station apparatus according to any one of claims 1 to 3 . 5. The control unit according to claim 1, wherein in the discovery mode, the transmission / reception processing units other than the one transmission / reception processing unit among the plurality of transmission / reception processing units are controlled to be in a sleep state. The station side apparatus of description. WDM / TDM-PON optical communication network system having a plurality of subscriber-side terminals and a station-side device having a plurality of external ports that can connect the plurality of subscriber-side terminals via a common optical transmission line Because
The station side device
A plurality of optical transmission / reception units provided for the number of the plurality of external ports, transmitting / receiving optical signals by light emitting elements and light receiving elements, and the transmission / reception wavelengths of the optical signals being adjustable ,
Provided for the number of the plurality of external ports, drive the light emitting elements of each of the plurality of optical transmission / reception units according to transmission data, and receive from the output signals of the light receiving elements of each of the plurality of optical transmission / reception units A plurality of transmission / reception processing units for obtaining data;
A changeover switch circuit disposed between the plurality of optical transmission / reception units and the plurality of transmission / reception processing units, and for switching an electrical connection between the plurality of optical transmission / reception units and the plurality of transmission / reception processing units;
An AWG router disposed between the optical signal transmission / reception terminal of each of the plurality of optical transmission / reception units and the plurality of external ports;
Control means for controlling the transmission / reception wavelengths of the plurality of optical transmission / reception units, the processing operation of the plurality of transmission / reception processing units and the switching operation of the changeover switch circuit ,
The control means selects one transmission / reception processing unit from among the plurality of transmission / reception processing units in a discovery mode in which registration processing is performed for an unregistered subscriber-side terminal among the plurality of subscriber-side terminals. Enabling the one transmission / reception processing unit to perform the operation of the registration processing, controlling the transmission / reception wavelengths of the plurality of optical transmission / reception units to a predetermined discovery wavelength, and switching the switching circuit to the one transmission / reception processing unit. An optical communication network system , wherein a transmission / reception terminal is electrically connected to any one of the plurality of optical transmission / reception units .

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