JP6130467B1 - Station side apparatus and network system - Google Patents

Abstract

When changing transmission capacity, settings of an optical transceiver and a MAC transmission unit are quickly matched. A bandwidth control unit outputs downlink traffic below a shaper bandwidth set by a bandwidth parameter instructed by a cooperation control unit, and an optical transmission unit is set by a transmission parameter instructed by the cooperation control unit. When transmitting a downstream optical signal to the subscriber apparatus with a transmission capacity of the transmission device, the cooperation control unit changes either the transmission capacity set in the optical transmission unit and the shaper band set in the band control unit, The transmission parameter to be instructed to the optical transmission unit and the band parameter to be instructed to the band control unit are determined so that the transmission capacity to be set and the shaper band to be set match after the change, and the transmission parameter Is used to instruct the optical transmission unit to change the setting, and the band parameter is used to instruct the band control unit to change the setting. . [Selection] Figure 2

Description

  The present invention relates to a station-side device and a network system.

  In recent years, with the spread of the Internet, there has been an increasing demand for speeding up communication in networks. In order to meet this demand for speeding up, PON (Passive Optical Network) is spreading.

  The PON is a single fiber connected to the OLT in order to connect the accommodation station (OLT: Optical Line Terminal) installed in the station and the network unit (ONU: Optical Network Unit) installed in each user's home. Is a network in which each of a plurality of branched fibers is connected to each of a plurality of ONUs.

  When a network is constructed by such a PON, the fiber laying cost is low, and it is possible to communicate at high speed because optical transmission is used. For this reason, it is currently spreading throughout the world.

  Among the methods using PON, optical signals of different wavelengths are used for downstream transmission signals from the OLT to the ONU and upstream transmission signals from the ONU to the OLT, and each ONU signal is time-divided. TDM (Time Division Multiplexing) -PON is widely used. This TDM-PON includes B-PON (Broadband PON), E-PON (Ethernet PON) (Ethernet is a registered trademark, the same applies hereinafter), G-PON (Gigabit Capable PON), 10G-EPON, XG-PON, etc. This is the method adopted in the standard.

  Furthermore, as a next-generation PON candidate, there is a method using WDM / TDM-PON in which conventional TDM-PONs are bundled at a plurality of wavelengths. This WDM / TDM-PON can realize larger capacity communication by using a plurality of wavelengths.

  Since current optical access networks use such new and old generation communication standards together, wavelength resources are depleted. And, when multiplexing and communicating with a plurality of wavelengths, it is important to save wavelength resources.

  Therefore, an optical access network whose transmission capacity is variable according to the communication situation will be required in the future. There is a need for an optical access system that can change transmission capacity by dynamically changing various transmission parameters.

  In OFDM-PON, an optical transceiver has been developed that can change the modulation scheme and symbol rate for each subcarrier and can also change the number of subcarriers, which is the sum of all subcarriers.

International Publication No. 2010/125803

  In WDM / TDM-PON, a conventional optical access network apparatus uses a certain capacity as a transmission capacity per wavelength. Also, a technology has been proposed in which a conventional apparatus uses a constant value as a shaper band for MAC layer processing in accordance with a certain transmission capacity.

  In addition, when an optical transceiver with variable number of subcarriers, multi-level number, symbol rate, etc. is introduced, the transmission capacity is variable, but the transmission capacity of the optical section when the transmission capacity is changed (frequency of about once per second). And the MAC layer rate are inconsistent.

  When mismatching occurs and transmission capacity <MAC layer rate, the buffer overflows in the PCS layer processing of the optical transceiver, and frame loss occurs. When transmission capacity> MAC layer rate, even if the transmission capacity is increased, the throughput is limited by the MAC layer, and the reserved transmission capacity is wasted.

  In addition, the mobile communication device described in Patent Document 1 changes a modulation method according to a change in quality of a radio section, and transmits a PAUSE frame when an accumulation amount exceeds a threshold in a buffer in the radio transmission device, and a MAC frame transmission device A technique for enabling a shaper is known (see FIG. 10 of Patent Document 1).

  In the technique of Patent Document 1, a change in transmission quality is used as a trigger for a change in transmission capacity, and the transmission capacity cannot be changed according to a change in traffic. For this reason, when a mismatch occurs between the transmission capacity and the MAC layer rate without changing the transmission quality, the above-mentioned problems such as frame loss occur.

  In addition, the mobile communication device described in Patent Document 1 can match the transmission capacity of the optical transceiver and the MAC layer rate, but the shaper is not used after the buffer storage amount of the optical transceiver exceeds the threshold. If enabled and the PAUSE is received, the shaper band is lowered, which causes a problem that the rate tracking speed in the MAC layer becomes slow. As a result, in high-speed optical communication, a large-capacity buffer is required on the optical transmitter / receiver side, or frame loss occurs due to buffer overflow.

  In this way, in a communication system capable of changing the transmission capacity, an OLT capable of following the setting of the optical transceiver and the MAC layer processing at a high speed with respect to the change of the transmission capacity is realized, and the communication quality when the capacity is changed The purpose is to prevent decline.

  In order to solve the above problems, the present invention provides a station-side device that transmits an optical signal to a subscriber device, a band control unit that outputs received downlink traffic, and downlink traffic output from the band control unit An optical transmission unit that transmits a downstream optical signal to the subscriber device, a band control unit, and a cooperation control unit that connects to the optical transmission unit, and the band control unit includes the cooperation control unit The downlink traffic is output with a bandwidth less than or equal to the shaper band set by the band parameter instructed by the optical transmission unit, and the optical transmission unit has the transmission capacity set by the transmission parameter instructed by the cooperation control unit and the downlink optical signal To the subscriber unit, and the cooperation controller changes either the transmission capacity set in the optical transmitter or the shaper band set in the band controller. If the transmission capacity to be set and the shaper band to be set are matched after the change, a transmission parameter to be instructed to the optical transmission unit and a band parameter to be instructed to the band control unit are determined, The optical transmission unit is instructed to change the setting using the transmission parameter, and the band control unit is instructed to change the setting using the band parameter.

  ADVANTAGE OF THE INVENTION According to this invention, in the communication system which can change transmission capacity, it is possible to follow the setting of an optical transmitter / receiver and the setting of a MAC layer process at high speed with respect to the change of transmission capacity. Problems, configurations, and effects other than those described above will be clarified by the following description of embodiments.

1 is a block diagram illustrating a configuration of an optical access system according to a first embodiment. It is explanatory drawing which shows the structure of OLT and ONU of Example 1. FIG. 3 is a flowchart illustrating processing by a cooperation control unit according to the first embodiment. It is a sequence diagram which shows the process between OLT and ONU for increasing transmission capacity based on the amount of downlink traffic of Example 1. FIG. FIG. 10 is an explanatory diagram illustrating an example of a downlink OFDM signal according to the second embodiment. It is explanatory drawing which shows the structure of OLT and ONU of Example 2. FIG. 10 is a flowchart illustrating processing by a cooperation control unit according to the second embodiment. It is explanatory drawing which shows the example of the subcarrier group management table of Example 2. FIG. It is explanatory drawing which shows the structure of OLT and ONU of Example 3. It is explanatory drawing which shows the structure of OLT and ONU of Example 4.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In addition, the same code | symbol is provided to the common part in each figure.

(Optical access network)
First, the configuration of a system to which the present invention is applied will be described.

  FIG. 1 is a block diagram illustrating the configuration of the optical access system according to the first embodiment.

  The optical access network of the first embodiment includes four OLTs 10 (10-1 to 10-4), an optical splitter 30, a WDM coupler 70, a plurality of ONUs 20 (20-A-1 to 20-Dn4), and a plurality. Terminal 50 is provided. The OLT 10 is a station side device, and the ONU 20 is a subscriber device.

  The plurality of OLTs 10 are connected to the network 60. The network 60 may be the Internet or a network such as a LAN. The plurality of OLTs 10 transmit signals received from the network 60 to the ONU 20. In addition, the signal received from the ONU 20 is transmitted to the network 60.

  The plurality of OLTs 10-1 to 10-4 are connected to the WDM coupler 70. The WDM coupler 70 is connected to the optical splitter 30 via the trunk optical fiber 40-0. The optical splitter 30 is connected to the ONUs 20-A-1 to 20-Dn4 via the branch line optical fibers 40-A-1 to 40-Dn4. The terminals 50-A-1 to 50-Dn4 are connected to the ONUs 20-A-1 to 20-Dn4, respectively.

  Next, a method of multiplexing a plurality of OLT 10 signals will be described.

  The ONUs 20-A-1 to 20-An-n1 communicate with the OLT 10-1 using the downstream wavelength λAd and the upstream wavelength λAu. The ONUs 20-B-1 to 20-B-n1 communicate with the OLT 10-2 using the downstream wavelength λBd and the upstream wavelength λBu.

  The ONUs 20-C-1 to 20-Cn1 communicate with the OLT 10-3 using the downstream wavelength λCd and the upstream wavelength λCu. The ONUs 20-D-1 to 20-Dn1 communicate with the OLT 10-4 using the downstream wavelength λDd and the upstream wavelength λDu.

  Thus, in the optical access network of this embodiment, the plurality of OLTs 10 communicate with the ONU 20 by wavelength multiplexing at different wavelengths. Further, the OLT 10 according to the present embodiment multiplexes downlink communication and uplink communication by using a wavelength having a different downlink wavelength and uplink wavelength.

  Next, a downlink communication method between the OLT 10 and the ONU 20 will be described. The optical signal passing through the trunk optical fiber 40-0 includes the multiplexed optical signals of all wavelengths. Therefore, the ONU 20 receives downstream optical signals of all wavelengths.

  The ONU 20 receives only the wavelength to which its own ONU 20 belongs from the wavelength multiplexed downstream optical signal. Further, the ONU 20 identifies an optical signal addressed to itself from among optical signals having the same wavelength by determining whether or not the optical signal is addressed to itself based on the LLID that is an identifier in the frame.

  For example, the ONU 20-A-1 receives an optical signal including frames addressed to the ONU 20-A-1 to ONU 20-A-n1. Then, the ONU 20-A-1 transfers only the frame addressed to the ONU 20-A-1 to the upper layer processing based on the LLID, and discards the other frames. In this way, one OLT 10 and a plurality of ONUs 20 perform downlink communication.

  Next, an uplink communication method between the OLT 10 and the ONU 20 will be described. Each of the ONU 20-A-1 to ONU 20-A-n1 transmits a burst optical signal generated by itself during the period instructed by the OLT 10 using the same upstream wavelength λAu.

  By transmitting the burst optical signal during the instructed period, the ONU 20 prevents the upstream optical signals from the plurality of ONUs 20 from colliding with each other. The OLT 10 receives burst optical signals from a plurality of ONUs 20 multiplexed in a time division manner. In this way, one OLT 10 and a plurality of ONUs 20 can perform upstream communication.

  A plurality of OLTs 10 and a plurality of ONUs 20 can communicate by sharing the same optical fiber 40.

(WDM coupler 70)
The WDM coupler 70 receives upstream optical signals (wavelengths λAu to λDu) from the optical splitter 30 and demultiplexes them. The upstream optical signal received here is a signal combined by the optical splitter 30.

  The WDM coupler 70 transmits the upstream optical signal having the wavelength λAu to the OLT 10-1, the upstream optical signal having the wavelength λBu to the OLT 10-2, the upstream optical signal having the wavelength λCu to the OLT 10-3, and the upstream optical signal having the wavelength λDu. Output to OLT10-4.

  Also, the WDM coupler 70 is a downstream optical signal having a wavelength λAd from the OLT 10-1, a downstream optical signal having a wavelength λBd from the OLT 10-2, a downstream optical signal having a wavelength λCd from the OLT 10-3, and a downstream optical signal having a wavelength λDd from the OLT 10-4. Receive. These downstream optical signals are multiplexed and output to the trunk optical fiber 40-0.

(OLT10)
FIG. 2 is an explanatory diagram illustrating configurations of the OLT 10 and the ONU 20 according to the first embodiment.

  The OLT 10 includes an optical transceiver 120, a PHY transmitter 130, a MAC transmitter 140, a PHY receiver 150, a MAC receiver 160, and a cooperation controller 170. Below, the function and process of each part are described.

  The optical transceiver 120 transmits and receives an optical signal. Specifically, the optical transceiver 120 receives the upstream optical signal having the upstream wavelength λAu input from the WDM coupler 70, and converts the received upstream optical signal into a current signal. Further, the optical transceiver 120 converts and amplifies the converted current signal into a voltage signal, converts an analog electrical signal into a digital signal, and outputs the digital signal to the PHY receiver 150.

  In addition, the optical transceiver 120 converts the electrical signal input from the PHY transmitter 130 into an optical signal in OFDM (Orthogonal Frequency Division-Division Multiplexing) -PON of the downstream wavelength λAd, and is generated by this conversion. The optical signal is output to the WDM coupler 70 as a downstream optical signal. As a result, the optical transceiver 120 converts the downlink traffic into a downlink optical signal and transmits the downlink optical signal to the ONU 20.

  The optical transceiver 120 includes an optical transmitter for downstream optical signals and an optical receiver for upstream optical signals. The optical transmitter / receiver 120 can set the parameters of the optical signal in the OFDM-PON in the optical transmitter and the optical receiver in accordance with an instruction from the outside of the optical transmitter / receiver 120, and can change these parameters.

  The optical signal parameters include wavelength, modulation scheme, symbol rate, number of subcarriers, sampling rate, and the like. The optical transceiver 120 can change the transmission capacity of the downstream optical signal and upstream optical signal by changing these parameters. Then, the optical transceiver 120 transmits the downstream optical signal with the transmission capacity of the downstream optical signal, and receives the upstream optical signal with the transmission capacity of the upstream optical signal.

  The optical transmitter / receiver 120 can change the wavelength of the optical transmitter by having a device using a tunable laser as the optical transmitter. In addition, the optical transceiver 120 updates the setting of the signal processing unit (for example, configured by a DSP (Digital Signal Processor) device) included in the optical transceiver 120 with the modulation scheme, symbol rate, number of subcarriers, and sampling rate. This can be changed.

  In the OLT 10 according to the first embodiment, the cooperation controller 170 and the optical transceiver 120 are connected by a control signal line. The optical transceiver 120 can change the parameters in accordance with instructions from the cooperation control unit 170.

  The PHY transmission unit 130 is a processing unit that performs processing of the PHY layer in the downlink signal, and includes a PHY frame generation unit 1301 and an FEC encoder 1302. When the PHY transmission unit 130 receives a downlink frame from the MAC transmission unit 140, the FEC encoder 1302 performs downlink FEC encoding processing and encoding processing of various codes (for example, 64B66B) on the downlink frame.

  Then, after the encoding process, the PHY frame generation unit 1301 generates a PHY frame by adding a header or the like according to a PHY frame format defined between the OLT 10 and the ONU 20. Then, the PHY frame generation unit 1301 outputs the PHY frame to the optical transceiver 120.

  Note that the PHY frame generation unit 1301 may generate a PHY frame using parameters such as those used in the optical transceiver 120. The PHY frame generation unit 1301 illustrated in FIG. 2 is installed in a device different from the optical transceiver 120, but the PHY frame generation unit 1301 of the present embodiment may be installed in the optical transceiver 120.

  The MAC transmission unit 140 is a processing unit that executes processing of the MAC layer in the downlink signal, and includes a traffic shaper 1401 and a frame buffer 1402. When the MAC transmission unit 140 receives downlink traffic from the network 60, the MAC transmission unit 140 temporarily stores a frame included in the downlink traffic in the frame buffer 1402.

  The frame buffer 1402 is connected to the counter 1403. The counter 1403 may be installed in the MAC transmission unit 140 or may be installed outside the MAC transmission unit 140. The counter 1403 measures the amount of downlink traffic by monitoring the amount of frames stored in the frame buffer 1402.

  The traffic shaper 1401 outputs the downlink traffic by outputting the frame of the frame buffer 1402 toward the PHY transmitting unit 130. The traffic shaper 1401 is a bandwidth control unit of this embodiment.

  The traffic shaper 1401, for example, adjusts the frame transmission period and the size (burst size) output in one burst to limit the frame bandwidth to be equal to or less than the shaper bandwidth (upper limit bandwidth). Output. A method by which the traffic shaper 1401 sets parameters will be described later.

  When executing the processing, the traffic shaper 1401 uses parameters such as a frame transmission cycle, a burst size, and an upper limit bandwidth, and sets the bandwidth of the frame to be output by changing these parameters. The traffic shaper 1401 can dynamically change these parameters in accordance with instructions from the cooperation control unit 170.

  The PHY receiver 150 detects the PHY header of the PHY frame from the digital signal received from the optical transceiver 120 and analyzes the contents of the PHY header. Then, the PHY receiving unit 150 performs FEC decoding processing for each FEC codeword on the payload portion in the PHY frame, and then executes 64B66B decoding processing. Thereafter, the combined signal is output to the MAC receiving unit 160.

  The MAC receiving unit 160 receives a signal from the PHY receiving unit 150, detects and analyzes the header information of the MAC frame, and identifies whether it is a user data frame or a control frame. Then, the MAC receiving unit 160 converts the user data frame into a format corresponding to the connection interface with the network 60 and outputs it to the network 60.

  The cooperation control unit 170 is connected to the optical transceiver 120, the PHY transmission unit 130, and the MAC transmission unit 140 in the OLT 10 via a control signal line, and controls each processing unit. The cooperation controller 170 instructs the optical transceiver 120 to change the wavelength, modulation method, symbol rate, number of subcarriers, and sampling rate that are optical transmission parameters.

  Further, the cooperation control unit 170 instructs the PHY transmission unit 130 to include control information included in the header of the downstream PHY frame. Also, the cooperation control unit 170 acquires the downlink traffic amount from the counter 1403 of the MAC transmission unit 140 and instructs the setting of various parameters of the traffic shaper 1401 in the MAC transmission unit 140.

  The cooperation control unit 170 has a memory. The cooperation control unit 170 holds the parameter values set in the optical transceiver 120, the PHY transmission unit 130, and the MAC transmission unit 140 in its own memory.

  The OLT 10 according to the first embodiment can monitor the amount of downlink traffic and control the parameters of the optical transmitter / receiver 120 and the traffic shaper 1401 of the MAC transmitter 140 with the above-described configuration. Further, the OLT 10 according to the first embodiment can instruct the ONU 20 to change the parameters of the optical transceiver of the ONU 20 via the PHY frame header.

(ONU20)
The ONU 20 includes a PHY / MAC processing unit 220 and an optical transceiver 210. Hereinafter, functions of each device and each processing unit will be described.

  The optical transceiver 210 receives a downstream optical signal input from the optical fiber 40 and receives only a downstream optical signal having a designated wavelength. Furthermore, the optical transceiver 210 converts the received downstream optical signal into a current signal. Further, the optical transceiver 210 converts and amplifies the converted current signal into a voltage signal, converts an analog electrical signal into a digital signal, and outputs the digital signal to the PHY / MAC processing unit 220.

  The optical transceiver 210 converts the electrical signal input from the PHY / MAC processing unit 220 into an OFDM-PON optical signal having an upstream wavelength λAu, and outputs the converted optical signal to the optical fiber 40.

  The optical transceiver 210 converts a digital signal into an analog electrical signal, converts a voltage signal into a current signal, and further increases the specified wavelength when a digital signal is input from the PHY / MAC processing unit 220. The optical signal is converted into an optical signal, and the upstream optical signal is output from the optical fiber.

  Further, the optical transceiver 210 can set the parameters of the optical signal in the OFDM-PON in the optical transmitter and the optical receiver in accordance with an instruction from the outside of the optical transceiver 210, and can change these parameters. The optical signal parameters are wavelength, modulation scheme, symbol rate, number of subcarriers, and sampling rate.

  The optical transmitter / receiver 210 can change the wavelength of the optical transmitter by having a device using a tunable laser as the optical transmitter. In addition, the optical transceiver 210 can change the modulation scheme, symbol rate, number of subcarriers, and sampling rate by updating the settings of the signal processing unit (for example, configured by a DSP device) included in the optical transceiver 210. It is.

  In the configuration of the ONU 20 of the present invention, the PHY / MAC processing unit 220 and the optical transceiver 210 are connected not only by the main signal signal line but also by the control signal line. The optical transceiver 210 can change the parameters of the optical signal in accordance with the instruction of the PHY / MAC processing unit 220 received via the control signal line.

  The PHY / MAC processing unit 220 performs PHY layer processing and MAC layer processing for communication in the optical access network (PON) section. First, downlink signal processing will be described.

  The PHY / MAC processing unit 220 extracts a downstream PHY frame from the digital signal received from the optical transceiver 210 and analyzes the downstream PHY header. In addition, the PHY / MAC processing unit 220 executes FEC decoding processing and 64B66B decoding processing on the payload portion of the PHY frame.

  Thereafter, the PHY / MAC processing unit 220 extracts the header part of the MAC frame from the decoded signal, determines whether it is addressed to the own device based on the LLID in the header part, and discards the MAC frame other than the addressed to itself. To do. Then, the PHY / MAC processing unit 220 converts the MAC frame addressed to the PHY / MAC processing unit 220 into a frame format and a signal conforming to the interface standard with the terminal 50, and outputs them to the terminal 50.

  Next, upstream signal processing by the PHY / MAC processing unit 220 will be described. When the PHY / MAC processing unit 220 receives an uplink user data frame from the terminal 50, the PHY / MAC processing unit 220 adds the LLID assigned to the own device to the header and generates a MAC frame.

  Then, the PHY / MAC processing unit 220 performs 64B66B encoding processing and FEC encoding processing on the MAC frame. Then, the PHY / MAC processing unit 220 adds an upstream PHY frame header, generates an upstream PHY frame, and outputs the upstream PHY frame to the optical transceiver 210.

  The PHY / MAC processing unit 220 instructs the optical transceiver 210 to change the parameters of the optical signal based on the parameter changing instruction of the optical transceiver 210 of the ONU 20 stored in the header of the PHY frame by the OLT 10.

  According to the configuration of the ONU 20 according to the first embodiment, the ONU 20 can dynamically change parameters and transmit / receive optical signals in the OFDM-PON. The ONU 20 can receive an instruction to change the parameter of the optical transceiver 210 from the OLT 10, change the parameter, and transmit / receive an optical signal.

(PHY frame format)
A PHY frame format used between the OLT 10 and the ONU 20 in the first embodiment will be described. The downstream PHY frame format includes a burst delimiter (BD) area, a PHY control information area, a payload area, and an end-of-burst (EOB) area.

  The burst delimiter (BD) area indicates the start of the PHY frame, and stores a bit string of a specific pattern for representing the head of the downstream PHY frame.

  In the PHY control information area, a setting instruction to the optical transceiver 210 is stored in the ONU 20 from the OLT 10. For example, the PHY control information area stores information indicating the number of subcarriers to be set (SC_new), the setting start time (Tchange), the uplink burst transmission start time, and the like.

  The payload area includes a plurality of FEC code words output from the FEC encoder.

  The end-of-burst (EOB) area stores a bit string having a specific pattern indicating the end of the downstream PHY frame.

  According to such a PHY frame format, the OLT 10 can instruct the ONU 20 to change the parameters of the optical transceiver 210. Further, the OLT 10 can quickly change the parameters of the optical transceiver 210 by storing the parameter change instruction in the header of the PHY frame.

(Flowchart showing processing of cooperation control unit 170)
FIG. 3 is a flowchart illustrating processing performed by the cooperation control unit 170 according to the first embodiment.

  The cooperation controller 170 repeatedly executes the processing from the start to the end of the flowchart shown in FIG. Here, a case will be described in which the processing illustrated in FIG. 3 is periodically executed at a transmission capacity change cycle T_cap (predetermined). However, the OLT 10 performs the processing illustrated in FIG. 3 when registration or cancellation of the ONU 20 occurs. You may perform the process shown in at any time.

  First, the cooperation control unit 170 acquires the downlink traffic amount from the counter 1403 of the MAC transmission unit 140. For example, the counter 1403 may measure the cumulative value of the frame buffer 1402 in bytes, and the cooperation control unit 170 may acquire the cumulative value from the counter 1403. And the cooperation control part 170 may calculate the difference of the cumulative value measured in the last process (previous change period T_cap) and the cumulative value measured this time as a downlink traffic amount (S101).

  Further, the counter 1403 may calculate the downlink traffic amount, and the cooperation control unit 170 may acquire the calculated downlink traffic amount.

  Next, based on the acquired amount of downlink traffic, the cooperation controller 170 transmits the transmission capacity of the downstream optical signal to be set in the PON section (the transmission capacity of the downstream optical signal to be set in the optical transceiver 120: the transmission capacity after the change) ) And the shaper band to be set in the traffic shaper 1401 in the MAC transmission unit 140 (the changed shaper band) (S102).

  In step S102, the cooperation control unit 170 sets the parameter for setting the transmission capacity in the optical transceiver 120 and the parameter for setting the shaper band in the traffic shaper 1401, the transmission capacity after change and the parameter after change. It is determined so that it matches the shaper band. This is because the transmission capacity and shaper bandwidth that can be realized may be determined in stages depending on the parameters set in the optical transceiver 120 and the traffic shaper 1401. A specific processing example of a method for determining parameters so that transmission capacity and shaper band to be set match, and a method for determining transmission capacity and shaper band will be described later.

  In the above-described processing, the cooperation control unit 170 assumes that the transmission capacity and the shaper band are changed when the downlink traffic volume is acquired, and determines the transmission capacity and the shaper band based on the downlink traffic volume. Thus, the transmission capacity can be changed as needed according to the amount of downlink traffic.

  However, the cooperation control unit 170 according to the present embodiment determines the transmission capacity and shaper band newly acquired from the outside of the cooperation control unit 173 as the transmission capacity and shaper band set in the optical transceiver 120 and the traffic shaper 1401. Also good.

  For example, when the cooperation control unit 170 acquires information indicating any of the transmission capacity and shaper band after the setting change from another computer connected to the OLT 10, it is necessary to change either the transmission capacity or the shaper band. In step 102, the transmission capacity and the shaper band indicated by the acquired information may be determined as the changed transmission capacity and the changed shaper band.

  In addition, when acquiring any of the transmission capacity and the shaper band calculated by other processing units included in the OLT 10, the cooperation control unit 170 changes the transmission capacity and the shaper band indicated by the acquired information in step S102. The transmission capacity and the changed shaper band may be determined.

  Here, when only the shaper band is acquired, the cooperation control unit 170 obtains a transmission capacity that matches the acquired shaper band by using a method reverse to the method in step S102, and changes the obtained transmission capacity after the change. The transmission capacity may be determined. Specifically, for example, a transmission capacity that is a predetermined amount less than the acquired shaper band may be obtained as the matching transmission capacity.

  Then, after determining the parameter for setting the acquired shaper band and the parameter for setting the transmission capacity, the cooperation control unit 170 may execute step S103.

  By applying this embodiment even when only the shaper band is acquired, the cooperation control unit 170 also has a reason different from the requirement to change the transmission capacity (for example, the contract contents with the contractor using the ONU 20). The transmission capacity of the downstream optical signal can be adjusted.

  After determining the transmission capacity and the shaper band by the process of step S102, the cooperation controller 170 determines whether or not the transmission capacity set in the PON section changes (S103). For example, when the transmission capacity value currently set in the optical transceiver 120 is different from the transmission capacity value determined in step S102, the cooperation controller 170 may determine that the transmission capacity changes.

  Further, the cooperation control unit 170 may determine whether the transmission capacity changes by comparing parameters set in the optical transceiver 120. Specifically, when the parameter whose setting is changed according to the transmission capacity is only the number of subcarriers, cooperation control section 170 may determine whether there is a change in the number of subcarriers instead of the transmission capacity.

  When the currently set number of subcarriers is different from the number of subcarriers for setting the determined transmission capacity, the cooperation control unit 170 is different from the currently set transmission capacity. Therefore, it may be determined that the transmission capacity changes.

  When there is no change in the transmission capacity, the cooperation control unit 170 does not need to change the setting of the optical transceiver 120, and thus ends the process illustrated in FIG. If the transmission capacity is changed, the process proceeds to step S104 in order to change the settings of the optical transceiver 120 and the traffic shaper 1401.

  Note that step 103 is a process for preventing unnecessary setting changes of the optical transceiver 120, and the cooperation control unit 170 can instruct the optical transceiver 120 every time the step 101 is executed. Step 103 may not be executed. Further, the cooperation control unit 170 does not need to execute step 103 when step 102 is executed by acquiring a transmission capacity and a shaper band to be newly set from the outside of the cooperation control unit 170.

  In step S104, the cooperation control unit 170 determines whether the transmission capacity increases or decreases. For example, the cooperation controller 170 compares the currently set transmission capacity (transmission capacity before change) with the value of the transmission capacity (transmission capacity after change) determined in step S102, and determines the determined transmission capacity. Is higher than the currently set transmission capacity, it is determined that the transmission capacity increases. Further, when the determined transmission capacity is lower than the currently set transmission capacity, it is determined that the transmission capacity decreases.

  When it is determined that the transmission capacity is reduced, the cooperation control unit 170 executes steps S105 and S106. When it is determined that the transmission capacity is increased, the cooperation controller 170 executes steps S107 and S108.

  In step S <b> 105, the cooperation control unit 170 sets the shaper bandwidth determined in step S <b> 102 in the traffic shaper 1401 of the MAC transmission unit 140.

  After changing the setting of the traffic shaper 1401 in step S105, the cooperation controller 170 sets the transmission capacity determined in step S102 in the optical transceiver 120 and the PHY transmitter 130 of the OLT 10 (S106). Here, the coordination controller 170 instructs the optical transceiver 120 to determine the transmission capacity determined by instructing parameters (at least one of the number of subcarriers, the symbol rate, and the modulation scheme) for changing the transmission capacity. Set. In FIG. 3, the cooperation control unit 170 instructs the optical transceiver 120 of the OLT 10 to set the number of subcarriers.

  In step S106, the cooperation controller 170 stores an instruction to change the parameter of the optical transceiver 210 of the ONU 20 corresponding to the header of the PHY frame in order to change the parameter of the optical receiver of the optical transceiver 210 of the ONU 20. Thus, the PHY frame generation unit 1301 of the PHY transmission unit 130 of the OLT 10 is instructed.

  After changing the parameters of the optical transmitter / receiver 120 of the OLT 10 and the optical transmitter / receiver 210 of the ONU 20, the cooperation control unit 170 proceeds to step S109.

  In step S107, the cooperation controller 170 sets the transmission capacity determined in step S102 in the optical transceiver 120 and the PHY transmitter 130 of the OLT 10 using the same method as in step S106. Then, after changing the parameters of the optical transceiver 120 of the OLT 10 and the optical transceiver 210 of the ONU 20, the cooperation control unit 170 proceeds to step S108.

  When only considering preventing frame loss between the optical transceiver 120 and the traffic shaper 1401, the cooperation control unit 170 detects that the parameters of the optical transceiver 120 have been changed, and then executes step S108. May be.

  After step S107, the cooperation control unit 170 sets the shaper band determined in step S102 in the traffic shaper 1401 of the MAC transmission unit 140 using the same method as in step S105 (S108). After the setting change in step S108, the cooperation controller 170 proceeds to step S109.

  Here, the order of the traffic shaper 1401 setting and the parameter setting of the optical transceiver 120 and the PHY transmitting unit 130 differs depending on whether the transmission capacity decreases or increases. This is due to the following reason.

  In a transient state where the settings of the optical transceiver 120 of the OLT 10 and the optical transceiver 210 of the ONU 20 are changed, the relationship of (rate input to the PHY transmitter 130) ≦ (rate output from the PHY transmitter 130) is maintained. It is desirable to lean. By maintaining such a relationship, buffer overflow in the PHY transmitter 130 is prevented.

  Therefore, when the transmission capacity decreases, the cooperation controller 170 lowers the shaper band first to lower the rate input to the PHY transmitter 130, and then performs transmission in the optical transceiver 120 and the PHY transmitter 130. The capacity parameter (number of subcarriers, etc.) is changed to lower the rate output from the PHY transmitter 130.

  In addition, when the transmission capacity increases, the cooperation controller 170 changes the transmission capacity parameters (such as the number of subcarriers) in the optical transceiver 120 and the PHY transmitter 130 before being output from the PHY transmitter 130. After that, the rate input to the PHY receiver 150 is increased by increasing the shaper band.

  Thereby, the cooperation control unit 170 can prevent the occurrence of buffer overflow in the PHY transmission unit 130.

  Finally, in step S109, the cooperation control unit 170 stores the parameters set in the optical transceiver 120 and the parameters set in the MAC transmission unit 140 in a table managed by the cooperation control unit 170 in its own memory.

  According to the flowchart by the cooperation control unit 170 according to the first embodiment, the cooperation control unit 170 changes the transmission capacity of the optical transceiver 120 and the optical transceiver 210 according to the acquired downlink traffic, and the MAC transmission unit. The parameters of the 140 traffic shapers 1401 can be set so as to be consistent with each other. As a result, it is possible to prevent the occurrence of frame loss or the like due to buffer overflow in the PHY transmitter 130.

(Example of transmission capacity and shaper bandwidth determination method)
Details of the processing in step S102 are shown below. The cooperation controller 170 calculates the past downlink average traffic rate based on the latest downlink traffic volume acquired in step S101, the downlink traffic volume acquired in the past, and the change cycle T_cap.

  And the cooperation control part 170 estimates a future downlink traffic rate predicted value based on the calculated downlink average traffic rate. Then, the changed transmission capacity is determined based on the predicted downlink traffic rate. In the following, the cooperation control unit 170 determines the changed transmission capacity to be a value that is larger than and close to the predicted downlink traffic rate, but any value calculated based on the predicted downlink traffic rate Any value can be used.

  Here, the cooperation control unit 170 assumes that the past downlink average traffic rate and the future downlink traffic rate prediction value are the same, and estimates. However, the cooperation control unit 170 may estimate the future downlink traffic rate prediction value by any method, for example, calculate an increase rate or a decrease rate of the past downlink traffic rate, and calculate the future downlink traffic rate prediction value. It may be estimated.

  In the following, it is assumed that the parameter for changing the transmission capacity is only the number of subcarriers. Also, the cooperation controller 170 calculates the number of subcarriers that realizes the transmission capacity closest to the predicted future downlink traffic rate.

  First, the downlink transmission capacity in the PON section is calculated as in the following formula 1.

Transmission capacity = (symbol rate) × (number of bits per symbol) × (number of subcarriers) (Equation 1)
Here, the symbol rate and the modulation scheme are determined in advance, and the number of bits per symbol is determined according to the modulation scheme. For example, when the modulation method is QPSK, the number of bits per symbol is 2 bits, and when it is 16 QAM, the number of bits per symbol is 4 bits.

  Therefore, the cooperation control unit 170 calculates the number of subcarriers using the following formula 2.

(Number of subcarriers) = ROUNDUP [(predicted downlink traffic rate) / ((symbol rate) × (number of bits per symbol))] (Formula 2)
ROUNDUP is a function that rounds up the quotient and returns an integer value. In addition, the cooperation control unit 170 calculates the changed transmission capacity and shaper bandwidth when the calculated number of subcarriers is set in the optical transceiver 120 using, for example, Expression 3.

Transmission capacity = shaper band = (symbol rate) × (number of bits per symbol) × ROUNDUP [(predicted future traffic traffic rate) / ((symbol rate) × (number of bits per symbol))] 3)
The coordination controller 170 matches the changed transmission capacity and the changed shaper band by using Equation 3 to determine the changed transmission capacity and shaper band as the changed transmission capacity and shaper band. Let As a result, the rate output from the PHY transmitting unit 130 matches the rate input to the PHY transmitting unit 130, so that the cooperation control unit 170 prevents the occurrence of frame loss, waste of transmission capacity, and the like. Can do.

  In the example described above, only the number of subcarriers is changed, and the symbol rate and modulation scheme are not changed. However, the cooperation control unit 170 may determine parameter values by, for example, holding each parameter value candidate in advance and selecting an arbitrary combination from the candidates.

  Then, the transmission capacity may be changed by changing at least one parameter of the number of subcarriers, the symbol rate, and the modulation scheme. And the cooperation control part 170 can change transmission capacity to various values.

  In the above-described example, the transmission capacity and the shaper band are completely matched. However, the cooperation controller 170 may match the transmission capacity and the shaper band by any method. A specific method is described below.

  The rate of the MAC frame output from the MAC transmission unit 140 is controlled to be equal to or less than the shaper band set by the traffic shaper 1401. For this reason, the rate of the MAC frame output from the MAC transmission unit 140 is smaller than the shaper band (upper limit band) depending on the fluctuation of the rate of the MAC frame input from the network 60 to the MAC transmission unit 140.

  In this case, the relationship is (transmission capacity in the PON section) = (shaper band)> (rate output from the MAC transmission unit 140), and band utilization efficiency (= rate output from the MAC transmission unit 140 / in the PON section). (Transmission capacity) is less than 100%.

  Therefore, the cooperation control unit 170 may determine the shaper band to be slightly larger than the transmission capacity instead of matching the transmission capacity and the shaper band. For example, the cooperation control unit 170 may set the shaper band to a value larger than the transmission capacity by a certain ratio (for example, 1%), or may be set to a value larger than the transmission capacity by a predetermined value (for example, 1 Mbps). May be.

  Even when only the changed shaper band is acquired from the outside of the cooperation control unit 170 in step 102, the cooperation control unit 170 determines a value slightly smaller than the changed shaper band as the changed transmission capacity. May be.

  In this way, by determining the shaper band to be larger than the transmission capacity by a predetermined method, the cooperation control unit 170 can increase the rate output from the MAC transmission unit 140 and bring the band utilization efficiency closer to 100%. It is possible.

  However, if the shaper band is excessively increased, buffer overflow is likely to occur in the optical transceiver 120 and the PHY transmitter 130, and thus the linkage controller 170 satisfies both the band utilization efficiency and the buffer overflow rate. It is preferable to determine such a shaper band value.

  When importance is placed on suppressing the buffer overflow occurrence rate, the linkage controller 170 may decrease the increment = (shaper bandwidth−transmission capacity), and when importance is placed on bandwidth utilization efficiency, the increment = (shaper bandwidth−transmission capacity). ) Should be increased.

  By doing so, it is possible to determine the transmission capacity and the shaper band of matching values so as to satisfy both the band use efficiency and the buffer overflow occurrence rate.

(Details of traffic shaper 1401: parameter setting method)
The traffic shaper 1401 adjusts the shaper band by changing the maximum value of the amount of data to be transmitted in one burst and the transmission cycle for transmitting the burst. Buffers required by the optical transceiver 120 and the PHY transmitter 130 by arbitrarily setting the burst size and transmission cycle used by the traffic shaper 1401 based on the parameters set by the optical transceiver 120 and the length of the PHY frame. The capacity can be reduced.

  For example, by setting the transmission cycle to be approximately the same as the length of the PHY frame, the PHY transmission unit 130 may have a buffer capacity equal to or smaller than the PHY frame size, and the PHY transmission unit 130 can reduce the buffer capacity required. Is possible.

  Furthermore, in order to adjust the traffic shaper 1401 to the shaper band obtained by the above-described equation 3, the cooperation control unit 170 fixes the transmission cycle to the same level as the predetermined PHY frame size, and the optical transceiver 120 The burst size is calculated according to the shaper bandwidth obtained according to the transmission capacity.

  Then, the cooperation controller 170 changes the shaper band set in the traffic shaper 1401 by setting the calculated burst size and a fixed transmission cycle (if necessary) in the traffic shaper 1401. As a result, the buffer capacity required by the PHY transmitter 130 can be reduced and set to a shaper band suitable for the transmission capacity.

  Also, the cooperation control unit 170 obtains a transmission period based on the shaper bandwidth obtained by Expression 3 and a predetermined burst size, and sends the obtained transmission period and the predetermined burst size to the traffic shaper 1401. It may be set. As a result, the shaper band is changed.

(Change sequence of the number of downlink subcarriers)
FIG. 4 is a sequence diagram illustrating processing between the OLT 10 and the ONU 20 for increasing the transmission capacity based on the downlink traffic amount according to the first embodiment. In the following, processing will be described in chronological order.

  First, the OLT 10 measures the amount of downlink traffic (301: equivalent to step S101 in FIG. 3), and based on the measured amount of downlink traffic, the number of subcarriers SC_new, which is a parameter of the optical transceiver 120, The shaper band BW_new of the traffic shaper 1401 is determined (302, corresponding to step S102 in FIG. 3).

  The transmission capacity based on the parameters determined here increases in FIG. 4 from the past transmission capacity.

  Further, in the sequence 302, the OLT 10 also determines a time T_change for changing transmission parameters of the optical transceiver 120 of the OLT 10 and the optical transceiver 210 of the ONU 20. The cooperation control unit 170 of the OLT 10 performs processing time required for the control message TRxParameter_SET to propagate from the OLT 10 to the ONU 20, and processing required for the ONU 20 to issue a change instruction to the optical transceiver 210 after receiving the control message. The parameter change time T_change is determined so as to be equal to or greater than the total time.

  Next, after the sequence 302, the cooperation controller 170 of the OLT 10 generates a control message TRxParameter_SET storing the determined number of subcarriers SC_new and parameter change time T_change, and transmits it to the ONU 20.

  The OLT 10 and the ONU 20 change the parameter of the subcarrier number of the optical transceiver (120, 210) to the determined subcarrier number SC_new when the parameter change time comes. Then, the OLT 10 sets the shaper band of the traffic shaper 1401 to the determined shaper band BW_new.

  FIG. 4 shows an example of a sequence when the transmission capacity increases. However, when the transmission capacity decreases, the OLT 10 performs the parameter change process of the optical transceiver 120 and the change process of the shaper band setting in order. Run in reverse. When the transmission capacity is not changed, the OLT 10 executes only the process (301) for measuring the downlink traffic amount. The OLT 10 periodically executes the sequence shown in FIG.

  According to this sequence for changing the number of downlink subcarriers, parameters of the OLT 10 and the ONU 20 can be changed based on the amount of downlink traffic, and the downlink transmission capacity can be dynamically changed.

(Effects of Example 1)
As described above, according to the first embodiment, the transmission capacity of the optical transceiver 120 and the shaper band of the traffic shaper 1401 can be matched according to the amount of downlink traffic. In addition, since the cooperation controller 170 sets the determined parameters for each of the optical transceiver 120 and the MAC transmitter 140, the parameters of the optical transceiver 120 and the MAC transmitter 140 are matched even when the transmission capacity is changed. It is possible to shorten the time required.

  In the first embodiment, the transmission capacity is dynamically changed by changing the number of subcarriers in the entire OFDM signal. Since the OFDM signal communicates using a large number of subcarriers, the OLT 10 according to the second embodiment can communicate by dividing the subcarriers into a group of a plurality of ONUs 20 (herein referred to as subcarrier groups).

  In the second embodiment, the OLT 10 that has the same function as the first embodiment but can be divided into a plurality of subcarrier groups and can communicate with the ONU 20 is referred to as an OLT 11.

  The merit of dividing into a plurality of subcarrier groups is that different modulation schemes and symbol rates can be set for each subcarrier group, so the optimum modulation scheme and symbol rate are used according to the distance and transmission quality between OLT11 and ONU20. The point which can be transmitted / received is mentioned. And the point which can accommodate ONU20 more efficiently in the system which has a difference in distance for every ONU20 is mentioned.

  In the second embodiment, an embodiment in which the transmission capacity is dynamically changed for each subcarrier group in an OFDM-PON system that communicates with M subcarrier groups will be described. Below, Example 2 is demonstrated centering on the difference with Example 1. FIG.

(Downlink OFDM signal)
FIG. 5 is an explanatory diagram of an example of the downlink OFDM signal according to the second embodiment.

  In this example, M = 4, which is the number of subcarrier groups, and a different modulation scheme and symbol rate are determined for each subcarrier group.

  The OLT 11 transmits / receives a symbol rate B signal to / from the ONU 20 of the subcarrier group 1 using the QPSK modulation method.

  The OLT 11 transmits / receives a symbol rate 2B signal to / from the ONU 20 of the subcarrier group 2 using the QPSK modulation method.

  The OLT 11 transmits / receives a symbol rate B signal to / from the ONU 20 of the subcarrier group 3 using 16QAM modulation.

  The OLT 11 transmits / receives a symbol rate 2B signal to / from the ONU 20 of the subcarrier group 4 using 16QAM modulation.

  In the second embodiment, ONU 20 # 1 and ONU 20 # 2 belong to subcarrier group 1, ONU 20 # 3 belongs to subcarrier group 2, ONU 20 # 4 and 5 belong to subcarrier group 3, and ONU 20 # 6. , 7 and 8 belong to subcarrier group 4.

  The OLT 11 transmits these downstream optical signals, and the ONU 20 receives only signals in the range of the subcarrier group to which the own device belongs. For example, the ONU 20 # 1 receives the signal of the subcarrier group # 1.

  This downlink OFDM signal can change parameters such as the number of subcarriers used for each subcarrier group. Therefore, the OLT 11 can change the transmission capacity for each subcarrier group by changing parameters such as the number of subcarriers for each subcarrier group.

(Configuration of OLT 11)
FIG. 6 is an explanatory diagram illustrating configurations of the OLT 11 and the ONU 20 according to the second embodiment.

  The OLT 11 includes an optical transceiver 120, a PHY transmitter 131, a MAC transmitter 141, a PHY receiver 150, a MAC receiver 160, and a cooperation controller 171. The main difference between the OLT 10 of the first embodiment and the OLT 11 of the second embodiment is a PHY transmission unit and a MAC transmission unit. The PHY transmission unit 131, the MAC transmission unit 141, and the cooperation control unit 171 correspond to the PHY transmission unit 130, the MAC transmission unit 140, and the cooperation control unit 170 of the first embodiment.

  The PHY transmitter 131 according to the second embodiment has the same function as the PHY transmitter 130 according to the first embodiment, but includes a FEC encoder 1312 (1312-1 to 1312-M) for each subcarrier group. 130 and different.

  Further, the MAC transmission unit 141 of the second embodiment has the same function as the MAC transmission unit 140 of the first embodiment, but the frame buffer 1412 (1412-1 to 1412-M) and the traffic shaper 1411 (for each subcarrier group. 1411-1 to 1411 -M) is different from the MAC transmission unit 140. The MAC transmission unit 141 is different from the MAC transmission unit 140 in that it includes a distribution processing unit 1413.

  Further, as the PHY transmission unit 131 and the MAC transmission unit 141 are different from those in the first embodiment, the interfaces between the cooperation control unit 171 and the PHY transmission unit 131 and the MAC transmission unit 141 are different from those in the first embodiment. Hereinafter, functions and processes of the PHY transmission unit 131 and the MAC transmission unit 141, which are processing units different from those in the first embodiment, will be described.

  The MAC transmission unit 141 includes M traffic shapers 1411-1 to 1411-M, M frame buffers 1412-1 to 1412-M, a distribution processing unit 1413, and a counter 1414.

  The distribution processing unit 1413 analyzes the MAC header of the downlink user data frame input from the network 60, specifies the destination, and determines the subcarrier group to which the specified destination belongs. Then, the downlink user data frame is distributed to the frame buffer 1412 according to the determined subcarrier group.

  The distribution processing unit 1413 may specify the destination using the VLAN ID in the VLAN tag attached to the MAC frame, or may specify the destination using the destination MAC address. Also, the distribution processing unit 1413 holds, for example, a table indicating the correspondence relationship between the identifier of the ONU 20 and the number of the subcarrier group to which the ONU 20 belongs, and each user data frame belongs using this table and the identifier of the destination A subcarrier group may be determined.

  The traffic shapers 1411-1 to 1411-M have the same functions as the traffic shaper 1401 described in the first embodiment and execute the same processing. The downstream traffic band is shaped by the shaper band set by the cooperation control unit 171, and the frame stored in the frame buffer 1412 is output.

  The traffic shapers 1411-1 to 1411 -M are connected to the FEC encoders 1312-1 to 1312 -M, respectively, and transmit frames shaped in the designated bands to the FEC encoders 1312-1 to 1312 -M, respectively.

  The frame buffers 1412-1 to 1412 -M have the same functions as the frame buffer 1402 of the first embodiment and execute the same processing. The counter 1414 measures the amount of frames (downstream traffic amount) stored in the plurality of frame buffers 1412.

  The PHY transmission unit 131 includes one PHY frame generation unit 1311 and M FEC encoders 1312-1 to 1312 -M.

  The FEC encoders 1312-1 to 1312 -M have the same functions as the FEC encoder 1302 described in the first embodiment and execute the same processing. Each of the frames input from the traffic shapers 1411-1 to 1411-M is subjected to 64B66B encoding and FEC encoding processing, and is output to the PHY frame generation unit 1311 in units of FEC codewords.

  The PHY frame generation unit 1311 multiplexes the FEC codewords input from the M FEC encoders, adds a header for the downstream PHY frame to generate a downstream PHY frame, and outputs the downstream PHY frame to the optical transceiver 120 as a digital signal. To do. Further, as in the first embodiment, the PHY frame generation unit 1311 instructs the ONU 20 to change the parameters of the optical transceiver of the ONU 20 via the PHY frame header.

  The cooperation control unit 171 acquires the downlink traffic amount from the MAC transmission unit 141 as in the first embodiment, and sets the parameters of the optical transceiver 120 and the shaper band of the traffic shaper 1411 in the MAC transmission unit 141 based on the downlink traffic amount. To do.

  The difference between the cooperation control unit 171 of the second embodiment and the cooperation control unit 170 of the first embodiment is that the downlink traffic amount for each subcarrier group is acquired instead of the downlink traffic amount of one flow, and The point is that the parameters of the optical transceiver 120 and the shaper band of the traffic shaper 1411 for each subcarrier group are set.

  Unlike the cooperation control unit 170 according to the first embodiment, the cooperation control unit 171 includes a subcarrier group management table 310. The subcarrier group management table 310 indicates the modulation scheme, symbol rate, and number of subcarriers for each subcarrier group.

  According to the configuration of the OLT 11 according to the second embodiment, the amount of downlink traffic for each subcarrier group is monitored, and the parameters of the optical transceiver 120 and the shaper band of the traffic shaper 1411 of the MAC transmission unit 141 are set for each subcarrier group. Is possible.

(Configuration of ONU20)
The ONU 20 of the second embodiment has the same functional configuration as that described in the first embodiment. However, only the processing of the optical transceiver 210 is different from the first embodiment.

  In the second embodiment, the received downstream optical signal includes downstream optical signals to a plurality of subcarrier groups, and the modulation scheme and the symbol rate are different for each subcarrier group. For this reason, the ONU 20 according to the second embodiment cannot receive the optical signals of all the subcarrier groups, and selects and receives the optical signals of only a specific subcarrier group.

  As in the first embodiment, the optical transceiver 210 according to the second embodiment changes a parameter and executes processing in accordance with a parameter change instruction from the OLT 11.

  According to the configuration of the ONU 20 according to the second embodiment, it is possible to select only a specific subcarrier group from among the downstream optical signals composed of a plurality of subcarrier groups and receive the downstream optical signal. Also, when the number of subcarriers is changed for each subcarrier group, the ONU 20 of the second embodiment changes the parameters of the receiving unit of the optical transceiver 210 in accordance with the instruction from the OLT 11 as in the first embodiment. Can be executed.

(Flowchart showing processing of cooperation control unit 171)
FIG. 7 is a flowchart illustrating processing performed by the cooperation control unit 171 according to the second embodiment.

  Unlike the cooperation control unit 170 in the first embodiment, the cooperation control unit 171 in the second embodiment sets the shaper bandwidth of the subcarrier group in which the transmission capacity decreases, the transmission capacity setting of the optical transceiver 120 in all the subcarrier groups, and Parameters are set collectively for all subcarrier groups in the order of setting the shaper bandwidth of the subcarrier groups whose transmission capacity increases. Hereinafter, each step will be described.

  First, the cooperation control unit 171 acquires the downlink traffic amount for each subcarrier group from the counter 1414 of the MAC transmission unit 141. Similarly to the counter 1403 of the first embodiment, the counter 1414 may measure the cumulative value of the downlink traffic amount in each frame buffer 1412 in units of bytes, and the cooperation control unit 171 may acquire the accumulated value. And the cooperation control part 171 may calculate the amount of downlink traffic for every frame buffer 1412 (for every subcarrier group) from the difference with the accumulation value of the amount of downlink traffic at the time of the last acquisition (S201).

  Further, the counter 1414 may calculate the downlink traffic amount for each frame buffer 1412, and the cooperation control unit 171 may acquire the downlink traffic amount for each frame buffer 1412 from the counter 1414.

  Next, the cooperation control unit 171 determines the transmission capacity for each subcarrier group set in the PON section and the shaper band set in the traffic shaper 1411 of the MAC transmission unit 141 from the downlink traffic amount measured for each subcarrier group. (S202).

  The method for determining the transmission capacity and the shaper band, and the method for determining the parameter for setting the transmission capacity and the parameter for setting the shaper band are the same as in the first embodiment. However, unlike the first embodiment, the cooperation controller 171 determines a transmission capacity and a shaper band for each subcarrier group, a parameter for setting the transmission capacity, and a parameter for setting the shaper band.

  In addition, in step S202, the cooperation control unit 171 obtains the symbol rate, modulation scheme, and number of subcarriers for each subcarrier group from the subcarrier group management table 310 as necessary.

  Note that the linkage control unit 171 may determine the changed transmission capacity by determining at least one of the number of subcarriers, the symbol rate, and the modulation scheme based on the downlink traffic prediction value, as in the first embodiment. Good. Thereby, the cooperation control unit 171 can determine various values of transmission capacity for each subcarrier group.

  After step S202, the cooperation controller 171 determines whether or not there is a change in the transmission capacity of at least one subcarrier group (S203). The method for determining whether there is a change in the transmission capacity is the same as in the first embodiment.

  When there is no change in the transmission capacity in all the subcarrier groups, the cooperation controller 171 ends the process shown in FIG. 7, and when there is a change in the transmission capacity of at least one subcarrier group, the cooperation control unit 171 proceeds to the process of step S204. .

  In step S204, the cooperation control unit 171 determines whether or not a subcarrier group whose transmission capacity decreases can be specified. For example, when the cooperation control unit 171 can identify a subcarrier group whose transmission capacity is smaller than the currently set transmission capacity value, the transmission capacity determined in step S202 can be identified. judge.

  If the cooperation control unit 171 has identified at least one subcarrier group whose transmission capacity is reduced, the process proceeds to step S205. If it is determined that the subcarrier group whose transmission capacity decreases cannot be specified, the process of step S205 is skipped and the process of step S206 is executed.

  In step S205, the cooperation control unit 171 instructs the traffic shaper 1411 of the subcarrier group whose transmission capacity decreases to set the shaper band determined in step S202. When there are a plurality of subcarrier groups whose transmission capacity decreases, the cooperation control unit 171 instructs the traffic shapers 1411 of all the subcarrier groups whose transmission capacity decreases to set the determined shaper bandwidth.

  After the change of the setting of the traffic shaper 1411 is completed in step S206, the cooperation control unit 171 instructs each subcarrier group to set the transmission capacity determined in step S202 in the optical transceiver 120 of the OLT 11. In step S206 illustrated in FIG. 7, the cooperation control unit 171 changes the transmission capacity by setting the number of subcarriers in the optical transceiver 120, but at least one of the number of subcarriers, the symbol rate, and the modulation scheme is changed. The transmission capacity may be changed by setting.

  Further, in order to change the parameter of the optical receiver of the optical transceiver 210 of the ONU 20, the PHY transmitter 131 of the OLT 11 stores an instruction to change the parameter of the optical transceiver 210 of the ONU 20 corresponding to the header of the PHY frame. Instruct. The cooperation control unit 171 executes step S207 after changing the parameters of the optical transceiver 120 of the OLT 11 and the optical transceiver 210 of the ONU 20.

  When only the frame loss between the traffic shaper 1411 and the optical transceiver 120 is considered, the cooperation controller 171 may execute step S207 after changing the parameter setting of the optical transceiver 120.

  In step S207, the cooperation control unit 171 determines whether or not a subcarrier group whose transmission capacity increases can be specified. For example, when the subcarrier group having a larger transmission capacity determined in step S202 than the currently set transmission capacity value can be identified, the cooperation control unit 171 determines that the subcarrier group whose transmission capacity increases can be identified. .

  If the cooperation control unit 171 determines that at least one subcarrier group whose transmission capacity increases can be specified, the process proceeds to step S208. If it is determined that the group whose transmission capacity increases cannot be identified, the process of step S208 is skipped, and the process proceeds to step S209.

  In step S208, the cooperation control unit 171 instructs the traffic shaper 1411 of the subcarrier group whose transmission capacity increases to set the shaper band determined in step S202. When there are a plurality of subcarrier groups whose transmission capacity increases, the cooperation control unit 171 sets the determined shaper band in the traffic shaper 1411 of all the subcarrier groups that increase.

  Finally, in step S209, the cooperation controller 171 stores the parameters set in the optical transceiver 120 and the parameters set in the MAC transmitter 141 in a table managed by the cooperation controller 170 in its own memory.

  Here, the shaper band setting of the subcarrier group in which the transmission capacity decreases (S205), the transmission capacity setting of the optical transceiver 120 in all the subcarrier groups (S206), and the shaper band setting of the subcarrier group in which the transmission capacity increases. The reason why the parameters are set collectively for all subcarrier groups in the order of (S208) will be described below.

  To change the transmission capacity of a subcarrier group and increase the number of subcarriers in a subcarrier group under the condition that the total number of subcarriers of the OFDM optical signal transmitted by the optical transceiver 120 is constant, It is necessary to reduce the number of subcarriers in the group at the same time. Therefore, when the parameters of the optical transceivers 120 of the subcarrier groups are set at different timings, mismatch occurs between the subcarrier groups.

  Therefore, the cooperation control unit 171 needs to execute the parameter setting of the optical transmitter / receiver 120 collectively in all subcarrier groups.

  Further, as in the first embodiment, in a transient state in which the settings of the optical transceiver 120 of the OLT 11 and the optical transceiver 210 of the ONU 20 are changed, (rate input to the PHY transmitter 130) ≦ (output from the PHY transmitter 130) It is desirable to maintain the relationship between By maintaining such a relationship, buffer overflow in the PHY transmitter 130 is prevented.

  Therefore, the cooperation control unit 171 changes the shaper setting of the subcarrier group in which the transmission capacity decreases, then changes the setting of the optical transceiver 120, and finally sets the shaper band of the subcarrier group in which the transmission capacity increases. By maintaining the above-mentioned relationship. As a result, it is possible to prevent the occurrence of frame loss or the like in downlink traffic even when changing parameters.

  According to the processing by the cooperation control unit 171 in the second embodiment, even in a system composed of a plurality of subcarrier groups, the parameters of the optical transceiver 120 and the parameters of the traffic shaper 1411 of the MAC transmission unit 141 are determined according to the measured downlink traffic amount. Can be set so as to be consistent, and further, it is possible to prevent the occurrence of frame loss due to the setting change.

(Subcarrier group management table 310)
FIG. 8 is an explanatory diagram illustrating an example of the subcarrier group management table 310 according to the second embodiment.

  Subcarrier group management table 310 includes group number 311, modulation scheme 312, symbol rate 313, and number of subcarriers 314. Group number 311 indicates an identifier for uniquely identifying a subcarrier group.

  A modulation scheme 312 indicates a modulation scheme applied to a subcarrier of the subcarrier group indicated by the group number 311. The symbol rate 313 indicates a symbol rate applied to the subcarrier of the subcarrier group indicated by the group number 311. The number of subcarriers 314 indicates the number of subcarriers assigned to the subcarrier group indicated by the group number 311.

  The cooperation controller 171 refers to the subcarrier group management table 310 and determines the parameters of the optical transceiver 120 and the traffic shaper 1411.

  In the first embodiment, a system that performs communication using an OFDM optical signal is assumed, but the present invention is not limited to this. In Example 3, an embodiment using a system in which the transmission capacity is changed by changing the number of multiplexed wavelengths in the optical section will be described. Hereinafter, the difference from the first embodiment will be mainly described.

(OLT10)
The OLT 10 of the first embodiment uses one optical transceiver 120, but the OLT 10 of the third embodiment uses one wavelength multiplexing number variable optical transceiver 122 and one wavelength multiplexing number variable optical transceiver. 122 includes a plurality of optical transceivers 1221.

  FIG. 9 is an explanatory diagram illustrating configurations of the OLT 10 and the ONU 20 according to the third embodiment.

  The OLT 10 includes a wavelength multiplexing number variable optical transceiver 122, a PHY transmission unit 130, a MAC transmission unit 140, a PHY reception unit 150, a MAC reception unit 160, and a cooperation control unit 172. Hereinafter, functions and processes of the wavelength multiplexing number variable optical transceiver 122 and the cooperation control unit 172, which are the differences between the third embodiment and the first embodiment, will be described.

  The wavelength-multiplexable number variable optical transceiver 122 includes M optical transceivers 1221 (1221-1 to 1221-M) capable of transmitting and receiving optical signals at wavelengths assigned to each, and a distribution processing unit 1222.

  The M optical transceivers 1221 can communicate with the ONU 20 using the wavelength (λ1-1) and the wavelengths (λ1-2) to (λ1-M), respectively. For this reason, the wavelength multiplexing number variable optical transceiver 122 can transmit a downstream optical signal using a plurality of wavelengths.

  The distribution processing unit 1222 receives the digital electric signal received from the PHY transmission unit 130 and distributes the received bit string to the plurality of optical transceivers 1221.

  The distribution processing unit 1222 may distribute the received bit string in any unit, whether in bit units or byte units. The distribution processing unit 1222 multiplexes the bit sequence of the uplink signal received from the M optical transceivers 1221 and outputs the multiplexed signal to the PHY receiving unit 150. In addition, the wavelength multiplexing number variable optical transceiver 122 can select and process only a part of the M optical transceivers 1221 according to the instruction of the wavelength multiplexing number from the outside (for example, the cooperation control unit 172). Is possible.

  Here, when the transmission / reception bit rate of each optical transceiver 1221 is 1 Gbps and two optical transceivers 1221 are selected and processed effectively, the transmission capacity is 1 Gbps × 2 = 2 Gbps. Further, when 16 optical transceivers 1221 are effectively processed, the transmission capacity is 1 Gbps × 16 = 16 Gbps.

  Thus, the wavelength multiplexing number variable optical transceiver 122 can change the number of wavelength multiplexing by changing the number of optical transceivers 1221 to be processed, thereby dynamically changing the transmission capacity. .

  The cooperation control unit 170 according to the first embodiment issues an instruction to change the wavelength, modulation scheme, symbol rate, number of subcarriers, and sampling rate, which are parameters for transmitting / receiving an optical signal, to the optical transceiver 1221. The cooperation control unit 172 according to the third embodiment instructs the change of the wavelength multiplexing number as a parameter for transmitting and receiving an optical signal.

  The cooperation control unit 172 instructs the control information to be included in the header of the downlink PHY frame to the PHY transmission unit 130, acquires the downlink traffic amount from the MAC transmission unit 140, and the traffic shaper 1401 in the MAC transmission unit 140 The point of instructing the setting of various parameters is the same as in the first embodiment.

(ONU20)
The ONU 20 according to the third embodiment uses the wavelength multiplexing number variable optical transceiver 212. Since the function and processing of the wavelength multiplexing number variable optical transceiver 212 included in the ONU 20 are the same as those of the wavelength multiplexing number variable optical transceiver 122 of the OLT 10, description thereof is omitted.

(Example of calculation method of transmission capacity and shaper bandwidth)
In the first embodiment, parameters such as the number of subcarriers, symbol rate, and modulation method, and transmission capacity are calculated based on the amount of downlink traffic, and a shaper band that matches the transmission capacity is set. In the third embodiment, the number of wavelength multiplexing is calculated instead of parameters such as the number of subcarriers. Here, the transmission rate of the optical transceiver 1221 of each wavelength included in the wavelength multiplexing number variable optical transceiver 122 is constant regardless of the wavelength.

  The cooperation control unit 172 calculates the downlink transmission capacity (transmission capacity of the present embodiment) of the PON section by the following expression 4, and further calculates the wavelength multiplexing number by the following expression 5. Here, the cooperation control unit 172 estimates the future downlink traffic rate prediction value based on the downlink traffic amount as in the first embodiment.

Transmission capacity = (Transmission rate per wavelength) × (Number of wavelength multiplexing) (Formula 4)
(Number of multiplexed wavelengths) = ROUNDUP [(Future downlink traffic rate prediction value) / (Transmission rate per wavelength)] (Formula 5)
ROUNDUP is a function that rounds up the quotient and returns an integer value. When the calculated wavelength multiplexing number is set, the cooperation control unit 172 calculates the shaper bandwidth to be set in the traffic shaper 1401 using the following Equation 6.

Shaper band = (transmission rate per wavelength) × ROUNDUP [(predicted downlink traffic rate) / (transmission rate per wavelength)] (Formula 6)
By using the wavelength multiplexing number and the shaper band calculated in this way, the cooperation control unit 172 can match the transmission capacity and the shaper band.

  According to the third embodiment, even in a system in which the transmission capacity is changed by changing the number of wavelength multiplexing, the parameter setting of the wavelength multiplexing number variable optical transceiver 122 and the MAC transmission unit 140 can be matched. Further, by reducing the number of wavelength multiplexing used when the traffic is low, the wavelength resources required in the PON section can be saved, and the number of optical transceivers 1221 that perform communication processing is reduced, thereby reducing the power consumption of the OLT 10 and the ONU 20. It is also possible.

  In Example 1, although the system which communicates using an OFDM optical signal was assumed, this invention is not limited to this. In the fourth embodiment, an embodiment in a system in which the transmission capacity is changed by using a multi-rate TDM-PON optical transceiver 123 capable of supporting a plurality of rates will be described. Hereinafter, the difference from the first embodiment will be mainly described.

(OLT10)
The OLT 10 of the first embodiment uses one optical transceiver 120, but in the fourth embodiment, the multi-rate TDM-PON optical transceiver 123 is used.

  FIG. 10 is an explanatory diagram illustrating configurations of the OLT 10 and the ONU 20 according to the fourth embodiment.

  The OLT 10 includes a multi-rate TDM-PON optical transceiver 123, a PHY transmission unit 130, a MAC transmission unit 140, a PHY reception unit 150, a MAC reception unit 160, and a cooperation control unit 173. Hereinafter, functions and processes of the multi-rate TDM-PON optical transceiver 123 and the cooperation control unit 173, which are the differences between the first embodiment and the fourth embodiment, will be described.

  The multi-rate TDM-PON optical transceiver 123 includes a plurality of optical transceivers 1231 and a selector 1232 that can transmit and receive at different rates. Note that there are two optical transceivers 1231 shown in FIG. 10; a 10G optical transceiver 12331-1 capable of transmitting and receiving at 10 Gbps and a 2.5 G optical transceiver 12331-2 capable of transmitting and receiving at 2.5 Gbps. . The selector 1232 switches the optical transceiver 1231 that executes processing.

  The selector 1232 receives the digital electrical signal received from the PHY transmission unit 130 and outputs the received bit string to one of the optical transceivers 1231. Further, the multi-rate TDM-PON optical transceiver 123 selects the 10G optical transceiver 1231-1 or 2.5G optical transceiver 1231-2 according to the rate instruction from the outside (for example, the cooperation control unit 173). It is possible to execute communication processing.

  The cooperation controller 170 according to the first embodiment instructs the optical transceiver 120 to change the wavelength, modulation scheme, symbol rate, number of subcarriers, and sampling rate, which are parameters for transmitting and receiving an optical signal. The cooperation control unit 173 according to the fourth embodiment directly instructs the selected rate.

  The cooperation control unit 173 instructs the control information to be included in the header of the downlink PHY frame to the PHY transmission unit 130, acquires the downlink traffic amount from the MAC transmission unit 140, and sets the parameters of the traffic shaper 1401 in the MAC transmission unit 140 The point to be instructed is the same as that of the cooperation control unit 170 of the first embodiment.

(ONU20)
The ONU 20 of the fourth embodiment also uses the multi-rate TDM-PON optical transceiver 123. Since the function and processing of the multi-rate TDM-PON optical transceiver 123 included in the ONU 20 are the same as those of the multi-rate TDM-PON optical transceiver 123 of the OLT 10, description thereof will be omitted.

(Example of calculation method of transmission capacity and shaper bandwidth)
The cooperation control unit 170 according to the first embodiment calculates the number of subcarriers based on the amount of downlink traffic, and sets a shaper band that matches the number of subcarriers. The cooperation control unit 173 according to the fourth embodiment selects a rate instead of calculating the number of subcarriers.

  Specifically, the cooperation controller 170 predicts a future traffic rate (traffic rate prediction value) by the same method as in the first embodiment, and selects an optical transceiver 1231 having a rate closest to the predicted traffic rate prediction value. . Further, the cooperation controller 170 determines the shaper band to be the same value as the selected rate when the number of wavelength multiplexing is changed.

  Strictly speaking, the cooperation control unit 170 needs to consider overhead due to the header of the PHY frame, but it is assumed here that these overheads are so small that they can be ignored.

  According to the fourth embodiment, even in a system that selects the optical transceiver 1231 that performs communication processing at an optimum rate among a plurality of rates, the parameter settings of the optical transceiver 1231 and the MAC transmitter 140 are matched. Can do.

  In addition, this invention is not limited to an above-described Example, Various modifications are included. For example, the above-described embodiments have been described in detail for easy understanding of the present invention, and are not necessarily limited to those having all the configurations described. Further, a part of the configuration of one embodiment can be replaced with the configuration of another embodiment, and the configuration of another embodiment can be added to the configuration of one embodiment. In addition, it is possible to add, delete, or replace another configuration for a part of the configuration of each embodiment.

  Each of the above-described configurations, functions, processing units, and the like may be realized by hardware by designing a part or all of them with, for example, an integrated circuit. Each of the above-described configurations, functions, and the like may be realized by software by interpreting and executing a program that realizes each function by the processor. Information such as a program, a table, or a file that realizes each function can be placed in a recording device such as a memory, a hard disk, or an SSD (Solid State Drive), or a recording medium such as an IC card or an SD card.

  Further, the control lines and the information lines indicate what is considered necessary for the explanation, and not all the control lines and information lines on the product are necessarily shown. In practice, it may be considered that almost all the components are connected to each other.

  In addition, the following can be mentioned as typical ones of aspects of the present invention other than those described in the claims.

(1) A station-side device that transmits an optical signal to a subscriber device,
A bandwidth control unit for outputting received downlink traffic;
An optical transmitter that transmits a downstream optical signal based on downstream traffic output from the band controller to the subscriber unit;
A cooperation control unit connected to the band control unit and the optical transmission unit,
The bandwidth control unit outputs the downlink traffic below a shaper bandwidth set by a bandwidth parameter instructed by the cooperation control unit,
The optical transmission unit transmits the downstream optical signal to the subscriber unit with a transmission capacity set by a transmission parameter instructed by the cooperation control unit,
The cooperation control unit
When changing either the transmission capacity set in the optical transmission unit or the shaper band set in the band control unit, the transmission capacity to be set and the set shaper band are matched after the change. Determining a transmission parameter to instruct the optical transmission unit and a band parameter to instruct the band control unit;
Instructing the optical transmitter to change the setting using the transmission parameter,
A station-side apparatus that instructs the band control unit to change a setting using the band parameter.

(A1) The station side device according to (1),
The cooperation control unit
Obtain the changed shaper band set in the band control unit,
Determining the changed shaper bandwidth as the bandwidth parameter;
A station-side apparatus that determines a transmission parameter for setting a transmission capacity that matches the changed shaper band.

(10) The station side device according to (1),
The band control unit outputs the downlink traffic for each group determined according to the destination of the downlink traffic, with a shaper band or less determined for each group,
The optical transmission unit transmits a downstream optical signal generated by converting the downstream traffic to the subscriber device using a transmission capacity determined for each group,
The cooperation control unit
When one of the transmission capacity set in the optical transmission unit and the shaper band set in the band control unit is changed for each group, the set transmission capacity and the set shaper band match after the change. To determine a transmission parameter to instruct the optical transmission unit and a band parameter to instruct the band control unit for each group,
A station-side apparatus that instructs the optical transmission unit and the band control unit to change a setting for each group using the transmission parameter and the band parameter.

(11) The station side device according to (10),
The cooperation control unit
When changing the transmission capacity to be set in the optical transmitter, the transmission capacity after the change to be set in the optical transmitter is obtained for each group,
A first group having a transmission capacity after the change smaller than the transmission capacity before the change is identified from the plurality of groups;
After instructing the bandwidth control unit to change the setting of the first group using the bandwidth parameter of the first group, and after the bandwidth control unit has finished changing the setting of the first group Instructing the optical transmission unit to change the setting for each group using the transmission parameter for each group,
After the optical transmission unit has finished changing the setting for each group, the second group having a transmission capacity after the change greater than the transmission capacity before the change is identified from the plurality of groups,
The station-side apparatus, which instructs the band control unit to change the setting of the second group using the band parameter of the second group.

(A2) The station side device according to (10) or (11),
The optical transmitter transmits a downstream optical signal by orthogonal frequency division multiplexing,
The link control unit determines at least one of the number of subcarriers, the symbol rate, and the modulation scheme of each group as the transmission parameter.

10 OLT
120, 121, 210, 211 Optical transceiver 122, 212 Wavelength multiplexing number variable optical transceiver 123, 213 Multi-rate TDM-PON optical transceiver 130, 131 PHY transmitter 1301, 1311 PHY frame generator 1302, 1312 FEC encoder 140 , 141 MAC transmission unit 1401, 1411 Traffic shaper 1402, 1412 Frame buffer 150 PHY reception unit 160 MAC reception unit 170, 171, 172, 173 Cooperation control unit 20 ONU
220, 221, 222, 223 PHY / MAC processing unit 30 Optical splitter 40 Optical fiber 50 Terminal 60 Network 70 WDM coupler

Claims (10)

A station-side device that transmits an optical signal to a subscriber device,
A bandwidth control unit for outputting received downlink traffic;
An optical transmitter that transmits a downstream optical signal based on downstream traffic output from the band controller to the subscriber unit;
A cooperation control unit connected to the band control unit and the optical transmission unit,
The bandwidth control unit outputs the downlink traffic below a shaper bandwidth set by a bandwidth parameter instructed by the cooperation control unit,
The optical transmission unit transmits the downstream optical signal to the subscriber unit with a transmission capacity set by a transmission parameter instructed by the cooperation control unit,
The cooperation control unit
When changing either the transmission capacity set in the optical transmission unit or the shaper band set in the band control unit, the transmission capacity to be set and the set shaper band are matched after the change. Determining a transmission parameter to instruct the optical transmission unit and a band parameter to instruct the band control unit;
Instructing the optical transmitter to change the setting using the transmission parameter,
Instructing the bandwidth control unit to change the setting using the bandwidth parameter,
When the transmission capacity after the change is smaller than the transmission capacity before the change, the cooperation control unit instructs the band control unit to change the setting, and after the band control unit has finished changing the setting, the light Instruct the transmitter to change the settings,
When the transmission capacity after the change is larger than the transmission capacity before the change, the cooperation control unit instructs the optical transmission unit to change the setting, and after the optical transmission unit has finished changing the setting, A station-side device that instructs a bandwidth control unit to change a setting . The station side device according to claim 1,
The cooperation control unit
Obtain the changed transmission capacity set in the optical transmitter,
A shaper band that is the same value as the transmission capacity after the change is determined as a shaper band that matches the transmission capacity after the change,
Determine transmission parameters for setting the transmission capacity after the change,
A station apparatus for determining a band parameter for setting the determined shaper band. The station side device according to claim 1,
The cooperation control unit
Obtain the changed transmission capacity set in the optical transmitter,
A value larger than the changed transmission capacity is determined as a shaper band that matches the changed transmission capacity,
Determine transmission parameters for setting the transmission capacity after the change,
A station apparatus for determining a band parameter for setting the determined shaper band. The station side device according to claim 1,
The cooperation control unit
Obtain the traffic volume of the downlink traffic received by the bandwidth control unit,
A station-side apparatus that acquires a transmission capacity calculated based on the traffic amount as a transmission capacity set in the optical transmission unit. The station side device according to claim 1,
The optical transmitter transmits a downstream optical signal by orthogonal frequency division multiplexing (OFDM),
The link control unit determines at least one of the number of subcarriers, a symbol rate, and a modulation scheme as the transmission parameter. The station side device according to claim 1,
The optical transmitter transmits the downstream optical signal using a plurality of multiplexed wavelengths,
The said cooperation control part determines the number by which the said some wavelength is multiplexed to the said transmission parameter, The station side apparatus characterized by the above-mentioned. The station side device according to claim 1,
The cooperation control unit
Obtain the changed shaper band set in the band control unit,
Using the changed shaper bandwidth and a predetermined transmission period, obtain a burst size for outputting the downlink traffic,
The predetermined transmission period and the determined burst size are determined as band parameters for instructing the band control unit,
The band control unit changes the setting so as to output the downlink traffic using the predetermined transmission period and the obtained burst size in accordance with an instruction from the cooperation control unit. Side device. The station side device according to claim 1,
The cooperation control unit
When changing the shaper band set in the band control unit, obtain the changed shaper band set in the band control unit,
Using the changed shaper bandwidth and a predetermined burst size, obtain a transmission period for outputting the downlink traffic,
The predetermined burst size and the determined transmission period are determined as band parameters for instructing the band control unit,
The band control unit changes the setting so as to output the downlink traffic using the predetermined burst size and the determined transmission period according to an instruction from the cooperation control unit. Side device. A station-side device that transmits an optical signal to a subscriber device,
A bandwidth control unit for outputting received downlink traffic;
An optical transmitter that transmits a downstream optical signal based on downstream traffic output from the band controller to the subscriber unit;
A cooperation control unit connected to the band control unit and the optical transmission unit,
The bandwidth control unit outputs the downlink traffic below a shaper bandwidth set by a bandwidth parameter instructed by the cooperation control unit,
The optical transmission unit transmits the downstream optical signal to the subscriber unit with a transmission capacity set by a transmission parameter instructed by the cooperation control unit,
The cooperation control unit
When changing either the transmission capacity set in the optical transmission unit or the shaper band set in the band control unit, the transmission capacity to be set and the set shaper band are matched after the change. Determining a transmission parameter to instruct the optical transmission unit and a band parameter to instruct the band control unit;
Instructing the optical transmitter to change the setting using the transmission parameter,
Instructing the bandwidth control unit to change the setting using the bandwidth parameter,
The band control unit outputs the downlink traffic for each group determined according to the destination of the downlink traffic, with a shaper band or less determined for each group,
The optical transmission unit transmits a downstream optical signal generated by converting the downstream traffic to the subscriber device using a transmission capacity determined for each group,
The cooperation control unit
When one of the transmission capacity set in the optical transmission unit and the shaper band set in the band control unit is changed for each group, the set transmission capacity and the set shaper band match after the change. To determine a transmission parameter to instruct the optical transmission unit and a band parameter to instruct the band control unit for each group,
Using the transmission parameter and the band parameter, instruct the optical transmission unit and the band control unit to change the setting for each group,
When changing the transmission capacity to be set in the optical transmitter, the transmission capacity after the change to be set in the optical transmitter is obtained for each group,
A first group having a transmission capacity after the change smaller than the transmission capacity before the change is identified from the plurality of groups;
After instructing the bandwidth control unit to change the setting of the first group using the bandwidth parameter of the first group, and after the bandwidth control unit has finished changing the setting of the first group Instructing the optical transmission unit to change the setting for each group using the transmission parameter for each group,
After the optical transmission unit has finished changing the setting for each group, the second group having a transmission capacity after the change greater than the transmission capacity before the change is identified from the plurality of groups,
The station-side apparatus, which instructs the band control unit to change the setting of the second group using the band parameter of the second group .   A network system,
  A subscriber unit, and a station side device that transmits an optical signal to the subscriber unit,
  The station side device
  A bandwidth control unit for outputting received downlink traffic;
  An optical transmitter that transmits a downstream optical signal based on downstream traffic output from the band controller to the subscriber unit;
  A cooperation control unit connected to the band control unit and the optical transmission unit,
  The subscriber unit has an optical receiver that receives the optical signal transmitted from the station side device,
  The bandwidth control unit outputs the downlink traffic below a shaper bandwidth set by a bandwidth parameter instructed by the cooperation control unit,
  The optical transmission unit transmits the downstream optical signal to the subscriber unit with a transmission capacity set by a transmission parameter instructed by the cooperation control unit,
  The cooperation control unit
  When changing either the transmission capacity set in the optical transmission unit or the shaper band set in the band control unit, the transmission capacity to be set and the set shaper band are matched after the change. Determining a transmission parameter to instruct the optical transmission unit and a band parameter to instruct the band control unit;
  Instructing the optical transmitter to change the setting using the transmission parameter,
  Instructing the bandwidth control unit to change the setting using the bandwidth parameter,
  When the transmission capacity after the change is smaller than the transmission capacity before the change, the cooperation control unit instructs the band control unit to change the setting, and after the band control unit has finished changing the setting, the light Instruct the transmitter to change the settings,
  When the transmission capacity after the change is larger than the transmission capacity before the change, the cooperation control unit instructs the optical transmission unit to change the setting, and after the optical transmission unit has finished changing the setting, Instruct the bandwidth controller to change the setting,
  The network system according to claim 1, wherein the optical receiving unit receives the downstream optical signal from the subscriber unit with a transmission capacity set by a transmission parameter instructed by the cooperation control unit.

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