JP2014057192A - Slave station device, master station device, control device, optical communication system and power saving control method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a slave station device capable of reducing power consumption.SOLUTION: An ONU includes a power saving mode in which a sleep period to make an optical transmitter 141 into a power saving state and an active period to tentatively activate the optical transmitter 141 are repeated periodically. The ONU includes: receiver units 161-1, 161-2 for receiving data to be transmitted to an OLT 1; and based on the data, a power saving control unit 111 for calculating the sleep period which is the length of the sleep period capable of data transmission. On receipt of data in receiver units 161-1, 161-2, the sleep period length is set to be a sleep time calculated by the power saving control unit 111, so that data is transmitted to the OLT 1 in the active period.

Description

  The present invention relates to a slave station device, a master station device, a control device, an optical communication system, and a power saving control method.

  In a PON (Passive Optical Network) system, standardization of a power saving control protocol for powering down an ONU (Optical Network Unit) when there is no traffic has been studied (for example, see Non-Patent Document 1 below).

  In the PON system, communication is performed while synchronizing between an OLT (Optical Line Terminal) and the ONU so that uplink data transmitted from the ONU does not collide. The OLT which is the master station apparatus plans to give transmission permission to each ONU (slave station apparatus) so that uplink data does not collide. At this time, the OLT considers a delay due to the distance to each ONU. For this reason, the OLT measures the round trip time between each ONU. However, in transmission using an optical fiber, there are fluctuations in the transmission path such as jitter and wander, and therefore it is necessary to perform measurement periodically.

  For this reason, in the power saving control of a PON system, the technique which makes ONU change to a power saving state intermittently is examined. For example, a plurality of power saving modes (sleep modes) such as a doze mode (Tx sleep mode) in which the transmission function is intermittently stopped and a cyclic sleep mode (TRx sleep mode) in which the transmission / reception function is intermittently stopped are used. When performing power saving control, negotiation is performed between the OLT and the ONU for exchanging compatible sleep modes and parameters related to power saving control, and power saving control is performed based on parameters agreed upon by this negotiation. Is implemented.

  When the ONU can transition to the power saving mode, for example, when there is no data frame transmission / reception between the OLT and the ONU for a certain period of time, the OLT sends a sleep permission message, the ONU sends a sleep response message, and the power saving mode Transition to. During this power saving mode, no data frame is transmitted / received. When a data frame to be transmitted occurs in the OLT or ONU, a message exchange for canceling the power saving mode of the ONU is performed, and the data frame is released after canceling the power saving mode. Send and receive.

ITU-T (Telecommunication Standardization Sector of International Telecommunication Union), ITU-T Recommendation G. 987.3, October 2010

  In recent years, against the background of global warming, there is a strong demand for power saving for communication services including PON systems. Further power saving is expected for ONU.

  The present invention has been made in view of the above, and an object of the present invention is to obtain a slave station device, a master station device, a control device, an optical communication system, and a power saving control method that can reduce power consumption.

  In order to solve the above-described problems and achieve the object, the present invention provides a sleep period in which an optical transmitter connected to a master station device through an optical communication path and performing transmission processing to the master station device is in a power saving state. And a slave station device having a power saving mode that periodically repeats an active period in which the optical transmitter is temporarily activated, a reception unit that receives data to be transmitted to the master station device, and based on the data A sleep time calculation unit that calculates a sleep time that is a length of the sleep period during which the data can be transmitted, and when the reception unit receives the data, the length of the sleep period is set to the sleep time. The sleep time calculated by the time calculation unit is set, and the data is transmitted to the master station device during the active period.

  According to the present invention, there is an effect that power consumption can be reduced.

FIG. 1 is a diagram illustrating a configuration example of the PON system according to the first embodiment. FIG. 2 is a chart showing an example of the initial negotiation procedure. FIG. 3 is a chart illustrating an example of a procedure for shifting to the power saving mode. FIG. 4 is a diagram illustrating a configuration example of a power saving control unit of the OLT. FIG. 5 is a flowchart illustrating an example of a procedure for determining a sleep time based on downlink data in the sleep time calculation unit. FIG. 6 is a diagram illustrating a sequence diagram when changing the sleep time. FIG. 7 is a diagram illustrating how the start time of the active period of the ONU is estimated by the OLT. FIG. 8 is a chart showing an example of a control procedure when the start time is delayed by Δt. FIG. 9 is a diagram illustrating an example of a control method when a plurality of ONUs are simultaneously set to the power saving mode. FIG. 10 is a diagram illustrating an example of a control method in a case where the active period control method is changed according to the downlink data reception rate. FIG. 11 is a diagram illustrating an example of control for preventing overlapping of active periods. FIG. 12 is a diagram illustrating an example of an active period control procedure according to the second embodiment.

  Embodiments of a slave station device, a master station device, a control device, an optical communication system, and a power saving control method according to the present invention will be described below in detail with reference to the drawings. Note that the present invention is not limited to the embodiments.

Embodiment 1 FIG.
FIG. 1 is a diagram illustrating a configuration example of a first embodiment of a PON system (optical communication system) according to the present invention. As shown in FIG. 1, the PON system of this embodiment includes an OLT (also referred to as a station side optical communication device) 1 that operates as a master station device and an ONU (user side optical communication device) that operates as a slave station device. 10-1 to 10-3. The OLT 1 and the ONUs 10-1 to 10-3 are connected by the optical fiber 30 via the splitter 40. The splitter 40 branches the trunk optical fiber 30 connected to the OLT 1 into the number of ONUs 10-1 to 10-3. The ONU 10-1 is connected to the terminal 20-1 and the terminal 20-2. In this example, three ONUs are shown, but the number of ONUs is not limited to this, and any number may be used.

  The OLT 1 includes a control unit 2 (OLT control unit) that performs processing on the OLT side based on the PON protocol, a reception buffer 3 that is a buffer for storing uplink data received from the ONUs 10-1 to 10-3, A transmission buffer 4 that is a buffer for storing downlink data to be transmitted to the ONUs 10-1 to 10-3, an optical transceiver 5 that performs transmission / reception processing of optical signals, and a WDM (Wavelength) that wavelength-multiplexes uplink data and downlink data. A division multiplexing (WDM) 6 and a physical layer processing unit (PHY) 7 for realizing a physical interface function such as NNI (Network Node Interface) between a network (not shown) are provided. The optical transmitter / receiver 5 performs reception processing of the optical signals transmitted from the ONUs 10-1 to 10-3 and converts them into uplink data, and transmits them to the ONUs 10-1 to 10-3. And an optical transmitter (Tx: Transmitter) 52 that performs transmission processing of downlink data to be converted into an optical signal and transmits the optical signal. The control unit 2 includes a power saving control unit 21 that controls the power saving mode of the ONUs 10-1 to 10-3.

  The ONU 10-1 includes a control unit 11 that performs processing on the ONU side based on the PON protocol, a transmission buffer (upstream buffer) 12 that is a buffer for storing transmission data (upstream data) to the OLT 1, and an OLT 1 Receiving data (downlink buffer) 13, an optical transmitter / receiver 14, a WDM 15 that wavelength-multiplexes upstream data and downstream data, and terminals 20-1 and 20-2. And physical layer processing units (PHYs) 16-1 and 16-2 for realizing physical interface functions such as UNI (User Network Interface).

  The optical transceiver 14 includes an optical transmitter (Tx: Transmitter) 141 that performs transmission processing and an optical receiver (Rx: Receiver) 142 that performs reception processing. The control unit 11 includes a power saving control unit 111 that controls the optical transmitter 141 and / or the optical receiver 142 to an on state / off state, and is connected to the optical transceiver 14 through a signal line for power saving control. . The PHY 16-1 includes a reception unit (Rx: Receiver) 161-1 that performs reception processing, and a transmission unit (Tx: Transmitter) 162-1 that performs transmission processing, and the PHY 16-2 performs reception processing. It has a receiving unit (Rx: Receiver) 161-2 and a transmitting unit (Tx: Transmitter) 162-2 that performs transmission processing.

  In addition, although the number of terminals connected to the ONU 10-1 is two, the number of terminals is not limited to this, and any number may be used, and a physical layer processing unit (PHY) corresponding to the number of terminals is provided. Further, in FIG. 1, the configuration example of the ONU 10-1 is shown as a representative, but the ONUs 10-2 and 10-3 have the same configuration as the ONU 10-1.

  The data frame (downlink data) transmitted from the OLT 1 reaches all the connected ONUs 10-1 to 10-3. On the other hand, when transmitting data frames (uplink data) from the ONUs 10-1 to 10-3, the OLT 1 controls the transmission timing of the uplink data so as not to collide with data frames from other ONUs 10-1 to 10-3. .

  The uplink data transmission timing is controlled according to the following procedure, for example. The OLT 1 allocates a band (transmission permission time period) for transmitting a response signal (REPORT) to each ONU 10-1 to 10-3, and sends a transmission permission notification (GATE, grant) for notifying the allocated result to the ONU 10-1. To 10-3. The ONUs 10-1 to 10-3 receive the transmission permission notification and transmit a response signal describing the capacity of the data frame to be transmitted at the time permitted from the OLT 1 by the transmission permission notification. Based on the response signal received from the ONUs 10-1 to 10-3, the OLT 1 allocates a data frame transmission band so that the data frames from the ONUs 10-1 to 10-3 do not collide, and permits transmission of the allocated result. Send as notification. The ONUs 10-1 to 10-3 transmit data frames at the time permitted by the received transmission permission notification.

  Next, power saving control according to the present embodiment will be described. In this embodiment, the ONUs 10-1 to 10-3 are, as power saving modes, a doze mode (Tx sleep mode) for intermittently stopping the transmission function and a cyclic sleep mode (TRx sleep mode) for intermittently stopping the transmission / reception function. Assume that one or both of them are supported. In both the doze mode and the cyclic sleep mode, the sleep period in which the transmission function or the transmission / reception function is in a power saving state and the active period in which the transmission function or the transmission / reception function is returned from the power saving state to the normal state alternately Repeat intermittent operation. Hereinafter, in the present embodiment, the length (time) of one sleep period in the power saving mode is called a sleep time, and the length (time) of one active period is called an active time.

(Initial negotiation)
When realizing the power saving function, parameters necessary for power saving, such as sleep time and active time, are transmitted and received between the OLT 1 and the ONU 10-1 by the initial negotiation (configuration). FIG. 2 is a chart showing an example of the initial negotiation procedure. This initial negotiation procedure is performed, for example, after the discovery process is performed between the OLT 1 and the ONU 10-1, but the timing of performing the initial negotiation procedure is not limited to this. Here, the ONU 10-1 will be described as an example, but the same applies to the ONUs 10-2 and 10-3.

  The control unit 2 of the OLT 1 generates a request frame for requesting acquisition of the sleep parameter and transmits it to the ONU 10-1 (step S1). Specifically, the control unit 2 of the OLT 1 sends a request frame requesting acquisition of the sleep parameter to the Tx 52 of the optical transceiver 5. The request frame transmitted from the Tx 52 arrives at the ONU 10-1 via the WDM 6 and the optical fiber 30. The request frame that has arrived at the ONU 10-1 arrives at the power saving control unit 111 of the control unit 11 via the WDM 15 and the Rx 142 of the optical transceiver 14. Examples of the sleep parameter include the type of power saving mode supported by the ONU 10-1, sleep time, active time, and the like.

  When receiving the request frame, the ONU 10-1 transmits a sleep parameter to the OLT 1 (step S2). Specifically, the power saving control unit 111 of the ONU 10-1 outputs a frame storing the sleep parameter to the Tx 141 of the optical transceiver 15, and this frame arrives at the OLT 1 via the WDM 15 and the optical fiber 30. In OLT 1, this frame arrives at the control unit 2 via WDM 6 and Rx 51 of the optical transceiver 5.

  The control unit 2 of the OLT 1 examines the sleep parameter received from the ONU 10-1 (Step S3). Specifically, it is confirmed whether the received sleep parameter is valid, and the valid parameter is set to a value that instructs the ONU 10-1 as it is. If not valid, a new command that instructs the ONU 10-1 is used. Determine the sleep parameters. Then, the OLT 1 transmits a sleep parameter instructing from the OLT 1 to the ONU 10-1 (step S4).

  When receiving the sleep parameter from the OLT 1, the ONU 10-1 transmits a response message indicating that it has been received (step S5). When the OLT 1 receives this response message, the initial negotiation is completed. The initial negotiation procedure is not limited to this. Thereafter, when the conditions for shifting to the power saving mode are satisfied, the ONU 10-1 shifts to the power saving mode using the sleep time and the active time specified from the OLT 1 in the initial negotiation.

  FIG. 3 is a chart illustrating an example of a procedure for shifting to the power saving mode. As illustrated in FIG. 3, when the OLT 1 satisfies a condition for shifting the ONU 10-1 to the power saving mode, the OLT 1 permits an ONU 10-1 to shift to the power saving mode (for example, SleepAllow (TRx), SleepAllow (Tx)) is transmitted (step S6). When the ONU 10-1 receives the permission message, the ONU 10-1 transmits a response message to the OLT 1 (step S7), and transitions to the power saving mode. At this time, the ONU 10-1 shifts to the power saving mode using the sleep time and the active time specified from the OLT 1 in the initial negotiation.

  The procedure for shifting to the power saving mode is not limited to the example of FIG. 3 (referred to as pattern A). For example, an instruction message for instructing the ONU 10-1 to shift to the power saving mode is transmitted from the OLT 1 and the ONU 10-1 transmits a response message to the instruction message, and then the procedure for shifting to the power saving mode (pattern B) ). In the case of pattern B, the ONU 10-1 may shift to the power saving mode without transmitting a response message.

  Further, when the ONU 10-1 transmits a request message requesting the OLT 1 to shift to the power saving mode, the OLT 1 transmits a permission message for the request message, and the ONU 10-1 receives the permission message, the power saving mode. It is good also as a procedure (pattern C) which transfers to. When the OLT 1 does not permit the ONU 10-1 to shift to the power saving mode, the OLT 1 transmits a non-permission message that does not permit the transition to the power saving mode. When the non-permission message is received, the ONU 10-1 does not shift to the power saving mode.

  Furthermore, it is good also as a procedure (pattern D) which ONU10-1 transmits the report message which reports the transfer to power saving mode, and transfers to power saving mode. The above-mentioned permission message, instruction message, request message, etc. are power saving control messages. For example, PLOAM (Physical Layer Operations, Administration and Maintenance) messages (SleepAllow, etc.) can be used, but not limited to these. Control messages of the form

  Next, a method for determining the sleep time according to the present embodiment will be described. As described above, in the doze mode and the cyclic sleep mode, the intermittent operation is performed, and the sleep period in which the power is saved and the active period (temporary activation period) in which the power is restored are periodically repeated. The sleep time, which is the length of the sleep period, and the active time, which is the length of the active period, are usually determined by the initial negotiation as described above.

  Normally, in a PON system, the ONU shifts to the power saving mode when both uplink data and downlink data or no uplink data exists, and returns to the normal state from the power saving mode when both uplink data and downlink data or uplink data occurs. Send and receive data.

  On the other hand, depending on the rate of data transmitted from the ONU 10-1, there may be a case where the transmission / reception function does not always have to be energized. In the present embodiment, when uplink data and downlink data occur, the sleep time is determined according to the data rate, and the ONU 10-1 is operated in the power saving mode using the determined sleep time, thereby saving power. Data transmission is possible while maintaining the mode. A method for determining the sleep time for transmitting data while maintaining the power saving mode will be described below.

(Sleep time selection (downlink data transmission))
First, a method for determining a sleep time based on downlink data (downlink frame) will be described. FIG. 4 is a diagram illustrating a configuration example of the power saving control unit 21 of the OLT 1 according to the present embodiment. As illustrated in FIG. 4, the power saving control unit 21 includes a rate measurement unit 211, a delay time calculation unit 212, and a sleep time calculation unit 213. The rate measuring unit 211 measures the reception rate of the received frame (downlink data) by counting, for each ONU, frames addressed to the ONUs 10-1 to 10-3 that have arrived at the PHY 7 during a certain frame measurement time TFrameCount. . The delay time calculation unit 212 calculates an allowable delay time (allowable delay time) TDelay based on the port number and priority of the received frame. The sleep time calculation unit 213 determines the sleep time based on the measurement result of the rate measurement unit 211 and the allowable delay time. In the doze mode, since the ONU reception function is in a normal state, the sleep time based on downlink data is the sleep time for the cyclic sleep mode.

  FIG. 5 is a flowchart illustrating an example of a procedure for determining a sleep time based on downlink data in the power saving control unit 21. Here, an example of determining the sleep time of the ONU 10-1 will be described. First, the rate measuring unit 211 counts (counts) the number of received frames addressed to the ONU 10-1 that has arrived at the PHY 7 (step S11). Next, the rate measurement unit 211 determines whether or not the frame measurement time TFrameCount has elapsed (step S12), and when it has not elapsed (No in step S12), returns to step S11.

  When the frame measurement time TFrameCount has elapsed (Yes in step S12), the number of received frames (the number of received frames per frame measurement time TFrameCount) is notified to the sleep time calculation unit 213, and the sleep time calculation unit 213 sets the number of received frames. Based on this, a sleep time TSleepFrameCount (TSFC) in which the ONU 10-1 can receive a frame is calculated (step S13).

When the number of received frames per frame measurement time TFrameCount is B bits, the ONU 10-1 can receive a frame when the following equation (1) holds.
TActive / (TSleepFrameCount + TActive) ≧ B / (R × TFrameCount) (1)
Therefore, TSleepFrameCount may be the following equation (2).
TSleepFrameCount ≤ TActive x (R x TFrameCount / B-1) (2)

  The delay time calculation unit 212 estimates the allowable delay time based on the port number, priority, and the like of the frame addressed to the received ONU 10-1 (step S14), and notifies the sleep time. The timing for estimating the allowable delay time is not limited to after step S13, and may be performed at an arbitrary timing before step S13.

  The sleep time calculation unit 213 obtains a sleep time TSleepDelay (TSD) that satisfies the allowable delay time TDelay (step S15). Then, the sleep time calculation unit 213 determines whether or not the minimum value of TSleepFrameCount (ie, TActive × (R × TFrameCount / B−1)) is smaller than TSleepDelay (Step S16), and the minimum value of TSleepFrameCount is smaller than TSleepDelay. In the case (Yes in Step S16), the maximum value of the sleep time of the ONU 10-1 is determined as the minimum value of TSleepFrameCount (Step S17), and a control signal for notifying the maximum value of the sleep time to the ONU 10-1 is transmitted (Step S19). The process is terminated.

  If the minimum value of TSleepFrameCount is equal to or greater than TSleepDelay (No in step S16), the maximum value of the sleep time of the ONU 10-1 is determined as TSleepDelay (step S18), and the process proceeds to step S19. If there is no TSleepFrameCount that satisfies the above equation (2), the sleep time is not changed, but the normal mode is restored.

  The OLT 1 performs the above operation for each sleep time update cycle TSleepUpdate. As a result, the ONU 10-1 receives the maximum value of the sleep time for each sleep time update cycle TSleepUpdate, and sets the received value as the maximum value of the sleep time. As described above, by using the determined sleep time, in the power saving mode of the ONU 10-1, the ratio between the sleep period and the active period is a rate at which a downlink frame can be received. However, when actually transmitting downlink data from the OLT 1, it is necessary to know the start time of the active period of the ONU 10-1 in addition to the ratio of the sleep period and the active period. Also, when the determined sleep time is notified, it is necessary to transmit the active period of the ONU 10-1, so that it is necessary to know the start time of the active period. For example, the OLT 1 obtains the start time of the active period of the ONU 10-1 by the following method.

  In addition, when a plurality of services are included in the downlink data addressed to the ONU 10-1, and there are a plurality of allowable delay times, the TSleepDelay may be obtained based on the smallest allowable delay time.

  Here, both TSleepFrameCount and TSleepDelay are obtained and the smaller value is determined as the sleep time. However, only one of them may be obtained and the obtained value may be determined as the sleep time.

  FIG. 6 is a diagram illustrating a sequence diagram in the case where the sleep time is determined and the sleep time is changed as described above. The sleep period 101 indicates that the ONU 10-1 is a sleep period, and the active period 102 indicates that the ONU 10-1 is an active period. In FIG. 6, the OLT 1 detects downlink data, determines a value based on the downlink data as a sleep time, and transmits a message notifying the sleep time to the ONU 10-1 (step S21). The ONU 10-1 transmits a response message to the received message (step S22), and changes the sleep time to the sleep time indicated by the message from the OLT 1. Then, the OLT 1 transmits downlink data to the ONU 10-1 (Step S23).

(Acquisition and setting of start / end time of active period (downlink data transmission))
In either the doze mode or the cyclic sleep mode, the ONU 10-1 periodically becomes an active period and transmits a response signal (Report) in order to maintain the link during the power saving mode.

  The OLT 1 can set values of the sleep time and active time of the ONU 10-1, but it is difficult to know whether the ONU 10-1 is in the sleep period or the active period at a specific time. However, the time during which the OLT 1 can receive the response signal from the ONU 10-1 is the active period of the ONU 10-1. Conversely, in a time period when the OLT 1 cannot receive a response signal from the ONU 10-1, there is a high possibility that the ONU 10-1 is in a sleep period.

  Accordingly, the OLT 1 can transmit a data frame during the active period of the ONU 10-1 by transmitting a control signal or a data frame for notifying the sleep time at the timing when the response signal is received from the ONU 10-1. Since the ONU 10-1 periodically becomes an active period, the start time of the next active time is estimated in advance based on the timing at which the response signal is received and the sleep time and active time instructed to the ONU 10-1. be able to.

  FIG. 7 is a diagram illustrating how the OLT 1 estimates the start time of the active period of the ONU 10-1. As shown in FIG. 7, the ONU 10-1 performs a periodic operation with a sleep time + active time as a cycle Tm in the power saving mode. Assuming that the ONU 10-1 transmits a response signal at the start of the active period (step S31), the start time Te of the next active period can be estimated by adding Tm to the reception time of the response signal. Further, the end time of the active period can be obtained based on the start time of the active period and the active time. Therefore, if the OLT 1 transmits downlink data to the ONU 10-1 between the estimated start time and end time of the active period, there is a high possibility that the ONU 10-1 can receive the data.

  Further, the OLT 1 can shift the start time of the ONU 10-1 to a desired time based on the start time of the active period estimated as described above. For example, assume that the start time of the active period is delayed by Δt. Considering that the ONU 10-1 transitions to the power saving mode after receiving the permission message from the OLT 1, as described with reference to FIG. 3, the ONU 10-1 is temporarily returned to the normal mode. Thus, the start time of the active period can be controlled by adjusting the timing for transmitting the permission message permitting the transition to the power saving mode.

  FIG. 8 is a chart showing an example of a control procedure when the start time is delayed by Δt. The OLT 1 transmits a signal (for example, SleepAllow (wakeup)) instructing the ONU 10-1 to return to the normal mode (step S32), and returns the ONU 10-1 to the normal mode. Thereafter, at a time after Δt from the estimated start time Te of the active period, a permission message (for example, SleepAllow (TRx)) permitting the transition to the power saving mode is transmitted to the ONU 10-1 (step S33). ). Thereby, the start time of the active period of the ONU 10-1 is delayed by Δt from Te. In this way, the OLT 1 can control the start time of the active period of the ONU 10-1. As shown in FIG. 3, when the ONU 10-1 transmits a response message to the permission message, it shifts to the power saving mode after transmitting the response message. It may not be considered that the time from the reception of the permission message to the transmission of the response message is sufficiently smaller than Δt. The permission message may be transmitted delayed by the subtracted time.

  In the case of the above-described pattern C described as the procedure for shifting to the power saving mode, the OLT 1 can control the start time of the active period of the ONU 10-1 in the same procedure. In the case of pattern C of the procedure for shifting to the power saving mode, the OLT 1 can control the start time of the active period of the ONU 10-1 by the same procedure by adjusting the timing of the permission message transmitted from the OLT 1. In the case of the pattern D of the procedure for shifting to the power saving mode, the start time of the active period cannot be adjusted by the above procedure, but the pattern D generally shifts to the doze mode when there is no upstream data from the ONU. In the doze mode, since the downlink data can be received, it is not necessary to adjust the start time of the active period.

  The OLT 1 can estimate the start time and end time of the active period of the ONU 10-1 in the power saving mode by the procedure as described above, and can transmit the data frame so that the ONU 10-1 can receive only at this time. . Therefore, the OLT 1 can transmit downlink data during the power saving mode of the ONU 10-1 without losing a frame.

  Next, a method for determining the sleep time based on the reception rate of uplink data will be described. In the above description, an example has been described in which the OLT 1 determines the sleep time based on downlink data and transmits downlink data. Similarly, for uplink data transmission, it is possible to determine the sleep time based on the uplink data reception rate and transmit the uplink data.

(Sleep time selection (uplink data transmission))
The power saving control unit 111 of the ONU 10-1 includes a rate measuring unit 211, a delay time calculating unit 212, and a sleep time calculating unit 213, similarly to the power saving control unit 21 of the OLT 1, and determines the sleep time in the same manner as the OLT 1. . The ONU 10-1 counts the number of received frames that have arrived at Rx 161-1, 161-2 of the PHYs 16-1, 16-2 in the same manner as the OLT 1 described above. If the number of received frames counted by the ONU 10-1 in the frame measurement time TFrameCount is B bits, the TFrameCount based on the upstream data can be obtained by the above equation (2) in the same manner as the OLT 1 performed based on the downstream data. it can. Similarly to the OLT 1, the allowable delay time TDelay for uplink data is obtained based on the port number, priority, etc. of the received frame, and the sleep time TSleepDelay that satisfies TDelay is obtained. The smaller value of TSleepDelay and TFrameCount is set as the maximum value of the sleep time. Then, the sleep time is updated by the above procedure every update cycle TSleepUpdate, and transmitted to the OLT 1 as the maximum value of the sleep time of the ONU 10-1.

  When the notified sleep time is acceptable, the OLT 1 notifies the ONU 10-1 of the sleep time notified from the ONU 10-1. With this notification, the ONU 10-1 changes the sleep time.

  In this way, the ONU 10-1 can maintain the power saving mode by changing the sleep time even if uplink data occurs. The above operation can be applied both when the ONU 10-1 is in the doze mode and in the cyclic sleep mode.

  For example, when the upstream data is generated in the ONU 10-1 almost simultaneously with the generation of the downstream data to the ONU 10-1, the OLT 1 changes the sleep time and the ONU 10-1 also notifies the sleep time to the OLT 1. As described above, a case where both the OLT 1 and the ONU 10-1 determine the sleep time may occur when the ONU 10-1 is in the cyclic sleep mode. In this case, the OLT 1 is notified from the ONU 10-1. What is necessary is just to instruct | indicate to ONU10-1 the sleep time of the smaller one among the sleep time which it determined and the sleep time which self determined.

  In the above description, the sleep time is calculated based on the reception rate and allowable delay time of the downlink data received by the OLT 1 at the PHY 7, and the uplink data received by the ONU 10-1 at the PHYs 16-1 and 16-2. The example in which the sleep time is calculated based on the reception rate and the allowable delay time has been described. Similarly, the reception rate and the allowable delay time are received using the uplink data received by the OLT 1 from the ONU 10-1 to the optical receiver 51 and / or the downlink data received by the ONU 10-1 from the OLT 1 to the optical receiver 142. Based on this, the sleep time can be calculated. In this case, the OLT 1 calculates the sleep time in the cyclic sleep mode or the doze mode based on the reception rate of the uplink data and the allowable delay time, and the ONU 10-1 calculates the cyclic sleep based on the reception rate of the downlink data and the allowable delay time. The sleep time of the mode is calculated. When the ONU 10-1 calculates the sleep time of the cyclic sleep mode based on the downlink data reception rate and the allowable delay time, the sleep time is transmitted to the OLT 1, and the OLT 1 estimates the ONU 10-1 active period. To transmit downlink data during the active period.

  Further, when the ONU 10-1 is in the cyclic sleep mode, the OLT 1 may calculate the sleep time based on both the downlink data received by the PHY 7 and the uplink data received by the PHYs 16-1 and 16-2. . In this case, the OLT 1 uses the reception rate of the uplink data received by the PHYs 16-1 and 16-2, the sleep time calculated based on the allowable delay time, the reception rate of the uplink data received by the optical receiver 51, and the allowable The smaller one of the sleep time calculated based on the delay time may be selected as the sleep time. Similarly, when the ONU 10-1 is in the cyclic sleep mode, the ONU 10-1 sleeps based on both the upstream data received by the PHYs 16-1 and 16-2 and the downstream data received by the optical receiver 142. May be calculated.

  As described above, in the present embodiment, when uplink data or downlink data occurs, the ONU 10-1 transmits uplink data or receives downlink data and uplink data while the ONU 10-1 remains in the power saving mode. The sleep time is set based on the reception rate of the uplink data or downlink data so that the transmission can be performed. For this reason, even when uplink data or downlink data occurs, the ONU 10-1 can maintain the power saving mode, and can reduce power consumption compared to the conventional case.

  The above procedure is an example, and the active period may be estimated with higher accuracy by using other time parameters between the OLT 1 and the ONU 10-1, for example, RTT which is the total of round trip transmission delay times. it can.

Embodiment 2. FIG.
In the first embodiment described above, the control of the power saving mode of the single ONU 10-1 with the OLT 1 has been described. However, in this embodiment, the OLT 1 simultaneously sets the plurality of ONUs 10-1 to 10-3 to the power saving mode. The control when doing this will be described. The configuration of the PON system of the present embodiment is the same as that of the first embodiment. Components having the same functions as those of the first embodiment are denoted by the same reference numerals as those of the first embodiment, and redundant description is omitted.

  The sleep time determination method, active period start time estimation method, and adjustment method according to the present embodiment are the same as those of the first embodiment.

  As a control method when the OLT 1 simultaneously sets the plurality of ONUs 10-1 to 10-3 in the power saving mode, control is performed so that the active periods of the ONUs 10-1 to 10-3 do not overlap each other in the initial state. FIG. 9 is a diagram illustrating an example of a control method when a plurality of ONUs 10-1 to 10-3 are simultaneously set to the power saving mode. When the ONUs 10-1 to 10-3 are simultaneously shifted to the power saving mode, as shown in FIG. 9, the start times of the power saving mode are shifted so that the active periods do not overlap. In the PON system, in the downlink direction, since a plurality of ONUs 10-1 to 10-3 receive all downlink data, when transmitting downlink data addressed to the plurality of ONUs 10-1 to 10-3, the bandwidth is shared. become. Therefore, it is basically desirable to shift the active period, and the active period is shifted in this way at the start of the power saving mode.

  In the example of FIG. 9, for the sake of simplicity, it is assumed that the active time is the same value for all the ONUs 10-1 to 10-3 connected to the OLT 1 and transitions to power saving at the same time. The sleep time is different for each of the ONUs 10-1 to 10-3. Assume that the sleep times of the ONU 10-1, ONU 10-2, and ONU 10-3 are TSleep1, TSleep2, and TSleep3, respectively. The active period of the ONU 10-2 is started immediately after the end of the active period of the ONU 10-1, and the active time of the ONU 10-3 is started immediately after the end of the active period of the ONU 10-2.

On the other hand, when downlink data occurs, the sleep time is changed as described in the first embodiment. Even if downlink data occurs, it is desirable to shift the active period, but if the downlink data reception rate is low, downlink data can be transmitted and received even if the active period overlaps if the total reception rate is within the maximum bandwidth . Therefore, a method of controlling the active period in two ways as follows can be considered.
(A) When the downlink data reception rate is high (when the reception rate is a certain value or more)
The active periods of the respective ONUs 10-1 to 10-3 are shifted, and data is transmitted in different time zones for the ONUs 10-1 to 10-3.
(B) When the downlink data reception rate is low (when the reception rate is less than a certain value)
When the reception rate is equal to or higher than a certain value, data is transmitted by overlapping active periods of two or more ONUs 10-1 to 10-3 among the ONUs 10-1 to 10-3.

  FIG. 10 is a diagram illustrating an example of a control method in a case where the active period control method is changed according to the downlink data reception rate. In the example of FIG. 10, it is assumed that downlink data with a high reception rate is generated for the ONU 10-1, and downlink data with a low reception rate is generated for the ONUs 10-2 and 10-3. In this case, the ONU 10-1 and the ONUs 10-2 and 10-3 are controlled so that the active periods do not overlap. On the other hand, the ONU 10-2 and the ONU 10-3 are controlled so that the active periods overlap.

  As described with reference to FIG. 9, at the start of the power saving mode, control is performed so that the active periods do not overlap. When the power saving mode is continued, the sleep time is different for each of the ONUs 10-1 to 10-3, and two or more ONUs 10-1 to 10-3 may be simultaneously active. When downlink data is generated, if the active periods overlap in this way, the bandwidth for each ONU 10-1 to 10-3 is 1 / N (N is the ONU 10-1 to 10-3 in which the active periods overlap). Therefore, it is necessary to avoid overlapping or limit the bandwidth.

  The OLT 1 manages the sleep time and the active time for each of the ONUs 10-1 to 10-3. Since these values are constant during the sleep time update cycle TSleepUpdate, the sleep time update cycle TSleepUpdate is a cycle. If it is sufficiently longer than Tm, the time at which the active time overlaps can be estimated. Therefore, when it is estimated that two or more active times overlap, the active periods are prevented from overlapping by controlling the active periods of the ONUs 10-1 to 10-3 to be shifted before the estimated active period. Can do.

  FIG. 11 is a diagram illustrating an example of control for preventing overlapping of active periods. As shown in the upper part of FIG. 11, when the control for shifting the active period is not performed, it is assumed that the active periods of the ONU 10-1 and the ONU 10-2 overlap. If the OLT 1 estimates that this overlap occurs, the overlap between the active periods is prevented by shortening the sleep time of the ONU 10-2 and the ONU 10-3 one cycle before the overlap occurs. Therefore, a permission message instructing to shorten the sleep time in the active period immediately before the sleep time is shortened is transmitted to the ONUs 10-2 and 10-3. Then, in the next active period, a permission message instructing to restore the sleep time is transmitted to the ONUs 10-2 and 10-3. In the case of FIG. 11, control is performed so that the start time of the active period of the ONUs 10-1 to 10-3 is shifted similarly to the start state of the power saving power mode illustrated in FIG. 9.

  In the case of FIG. 11, the active period is prevented from overlapping by shortening the sleep time. However, there may be a case where the sleep time is longer than that for adjustment. In such a case, by increasing the sleep time, the ONUs 10-1 to 10-3 that do not satisfy the delay time allowed by the service are temporarily shifted to the normal mode in order to satisfy the delay time requirement, and then power saving is performed. Change to the mode and adjust the active period.

  FIG. 12 is a diagram illustrating an example of an active period control procedure according to the present embodiment. First, the OLT 1 determines whether or not active periods overlap due to the above estimation (step S41). If the active periods overlap (Yes in step S41), control is performed to change the sleep time before overlapping, and the start times of the active periods of the ONUs 10-1 to 10-3 are shifted (step S42). The OLT 1 determines whether there are ONUs 10-1 to 10-3 that do not satisfy the allowable delay time due to the change of the sleep time (step S43). When there are ONUs 10-1 to 10-3 that do not satisfy the allowable delay time (step S43 Yes), the ONUs 10-1 to 10-3 that do not satisfy the allowable delay time are changed to the normal mode (wake up), and then saved. The active period is adjusted by shifting to the power mode (step S44), and the process ends. If there are no ONUs 10-1 to 10-3 that do not satisfy the allowable delay time (No in step S43), the process ends. If it is determined in step S41 that the active periods do not overlap (No in step S41), the process ends. The above processing is performed, for example, at regular intervals.

  In the above, the control when the downlink data is generated has been described. When the uplink data is generated, in order to avoid the collision of the uplink data in the OLT 1, as in the case where the reception rate of the downlink data is high, the active period is not overlapped. Control the duration.

  As described above, in the present embodiment, when a plurality of ONUs 10-1 to 10-3 shift to the power saving mode at the same time, the active period is controlled not to overlap in the start state of the power saving mode. In addition, when low-rate downlink data occurs, overlapping of active periods is allowed. For this reason, even when a plurality of ONUs 10-1 to 10-3 simultaneously shift to the power saving mode, the effect of reducing power consumption can be obtained as in the first embodiment, and data collision can be prevented. it can.

  As described above, the slave station device, the master station device, the control device, the optical communication system, and the power saving control method according to the present invention are useful for the PON system, and particularly suitable for the PON system that performs the power saving control. .

  1 OLT, 2, 11 control unit, 3, 13 reception buffer, 4, 12 transmission buffer, 5, 14 optical transceiver, 6, 15 WDM coupler, 7, 16-1, 16-2 PHY, 16 GW functional unit, 17 communication type determination unit, 21,111 power saving control unit, 211 rate measurement unit, 212 delay time calculation unit, 213 sleep time calculation unit, 10-1 to 10-3 ONU, 20-1, 20-2 terminal, 30 Optical fiber, 40 splitter, 50 network, 51, 142 optical receiver, 52, 141 optical transmitter, 101 sleep period, 102 active period, 161-1, 161-2 receiver, 162-1, 162-2 transmitter .

Claims (41)

A sleep period in which an optical transmitter connected to the master station apparatus through an optical communication path and performing transmission processing to the master station apparatus is in a power saving state and an active period in which the optical transmitter is temporarily activated are periodically A slave station device having a repeated power saving mode,
A receiving unit for receiving data to be transmitted to the master station device;
A power saving control unit that calculates a sleep time that is a length of the sleep period in which the data can be transmitted based on the data;
With
When the reception unit receives the data, the length of the sleep period is set to the sleep time calculated by the power saving control unit, and the data is transmitted to the master station device during the active period. Slave station device.   The slave station device transmits the sleep time to the master station device, and when the sleep time is instructed from the master station device, sets the length of the sleep period to the sleep time. The slave station apparatus according to claim 1.   The slave station apparatus according to claim 2, wherein the sleep time is transmitted to the master station apparatus as a power saving control message, and an instruction of the sleep time from the master station apparatus is received as a power saving control message. . An optical receiver that is connected to a master station device through an optical communication path and that performs reception processing of data transmitted from the master station device; and an optical transmitter that performs transmission processing to the master station device; And a slave station device having a power saving mode that periodically repeats a sleep period in which the optical transmitter is in a power saving state and an active period in which the optical receiver and the optical transmitter are temporarily activated,
Based on the data, a power saving control unit that calculates a sleep time that is the length of the sleep period in which the data can be received;
With
A slave station device that transmits the sleep time to the master station device. The power saving control unit
A rate measuring unit for measuring a reception rate of the data;
A sleep time calculation unit for calculating the sleep time based on the reception rate;
5. The slave station device according to claim 1, comprising: The power saving control unit
An allowable time estimation unit that estimates an allowable delay time using one or more of the port number and priority of the data;
A sleep time calculation unit for calculating the sleep time based on the allowable delay time;
5. The slave station device according to claim 1, comprising: The power saving control unit
A rate measuring unit for measuring a reception rate of the data;
An allowable time estimation unit that estimates an allowable delay time using one or more of the port number and priority of the data;
A sleep time calculation unit for calculating the sleep time based on the reception rate and the allowable delay time;
5. The slave station device according to claim 1, comprising:   The sleep time calculation unit obtains a first sleep time based on the reception rate, obtains a second sleep time based on the allowable delay time, the first sleep time, the second sleep time, The slave station apparatus according to claim 7, wherein a smaller value of the values is calculated as the sleep time.   The slave station apparatus according to claim 6 or 7, wherein when there are a plurality of allowable delay times, the sleep time calculation unit calculates the sleep time based on the smallest allowable time.   The slave station apparatus according to claim 8, wherein when there are a plurality of allowable delay times, the sleep time calculation unit calculates the second sleep time based on the smallest allowable time. An optical transmitter connected to the master station device through an optical communication path and performing a transmission process to the master station device; and an optical receiver performing a reception process of downlink data transmitted from the master station device, the optical transmission A slave station device having a power saving mode that periodically repeats a sleep period in which the power receiver and the optical receiver are in a power saving state and an active period in which the optical transmitter and the optical receiver are temporarily activated,
A receiving unit for receiving uplink data to be transmitted to the master station device;
Based on the uplink data, a first sleep time that is the length of the sleep period in which the uplink data can be transmitted is calculated, and the length of the sleep period in which the downlink data can be received based on the downlink data A power saving control unit that calculates a second sleep time, and calculates a smaller one of the first sleep time and the second sleep time as a sleep time;
With
A slave station device that transmits the sleep time calculated by the power saving control unit to the master station device. An optical receiver that is connected to a master station device through an optical communication path and performs processing for receiving data transmitted from the master station device, and a sleep period in which the optical receiver is in a power saving state and temporarily the optical receiver A slave station device having a power saving mode that periodically repeats an active period for starting a device,
Based on the data, a power saving control unit that calculates a sleep time that is the length of the sleep period in which the data can be received;
With
A slave station device that transmits the sleep time to the master station device. Optical communication with a slave station device having a power saving mode that periodically repeats a sleep period in which the optical receiver and the optical transmitter are in a power saving state and an active period in which the optical receiver and the optical transmitter are temporarily activated A master station device connected by a road,
A receiving unit for receiving data to be transmitted to the slave station device;
A power saving control unit that calculates a sleep time that is a length of the sleep period in which the data can be received based on the data;
With
When the data is received by the receiving unit, a signal instructing to set the sleep time calculated by the power saving control unit as the sleep time of the power saving mode is transmitted to the slave station device. Master station device. A master station device connected by an optical communication path to a slave station device having a power saving mode that periodically repeats a sleep period in which the optical transmitter is in a power saving state and an active period in which the optical transmitter is temporarily activated. There,
Based on the data, a power saving control unit that calculates a sleep time that is the length of the sleep period in which the data can be transmitted in the slave station device;
With
A master station device transmitting a signal instructing to set the sleep time calculated by the power saving control unit as a sleep time in the power saving mode to the slave station device.   The master station device according to claim 13 or 14, wherein the signal is transmitted to the slave station device as a power saving control message. The power saving control unit
A rate measuring unit for measuring a reception rate of the data;
A sleep time calculation unit for calculating the sleep time based on the reception rate;
The master station device according to claim 13, 14, or 15. The power saving control unit
An allowable time estimation unit that estimates an allowable delay time using one or more of the port number and priority of the data;
A sleep time calculation unit for calculating the sleep time based on the allowable delay time;
The master station device according to claim 13, 14, or 15. The power saving control unit
A rate measuring unit for measuring a reception rate of the data;
An allowable time estimation unit that estimates an allowable delay time using one or more of the port number and priority of the data;
A sleep time calculation unit for calculating the sleep time based on the reception rate and the allowable delay time;
The master station device according to claim 13, 14, or 15.   The sleep time calculation unit obtains a first sleep time based on the reception rate, obtains a second sleep time based on the allowable delay time, the first sleep time, the second sleep time, 19. The master station device according to claim 18, wherein the smaller one of the values is calculated as the sleep time.   The master station apparatus according to claim 17 or 18, wherein when there are a plurality of allowable delay times, the sleep time calculation unit calculates the sleep time based on the smallest allowable time.   The master station apparatus according to claim 19, wherein when there are a plurality of allowable delay times, the sleep time calculation unit calculates the second sleep time based on the smallest allowable time. Optical communication with a slave station device having a power saving mode that periodically repeats a sleep period in which the optical receiver and the optical transmitter are in a power saving state and an active period in which the optical receiver and the optical transmitter are temporarily activated A master station device connected by a road,
A receiving unit for receiving downlink data received from the slave station device;
Based on the uplink data, a first sleep time that is the length of the sleep period in which the uplink data can be transmitted from the slave station device is calculated, and the downlink data is calculated based on the downlink data. Power saving that calculates a second sleep time that is the length of the sleep period that can be received by the device, and calculates a smaller value of the first sleep time and the second sleep time as the sleep time A control unit;
With
A master station device that transmits a signal instructing to set the sleep time calculated by the power saving control unit as a sleep time in the power saving mode to the slave station device.   23. The slave station apparatus estimates a start time of an active period to the slave station apparatus based on a reception time of a response signal transmitted from the slave station apparatus during the active period. The master station device according to any one of the above.   When delaying the active period of the slave station device by a predetermined time, a control signal for returning the slave station device from the power saving mode is transmitted to the slave station device, and is determined based on the estimated start time and the predetermined time. 24. The master station apparatus according to claim 23, wherein a control signal instructing start of the power saving mode is transmitted to the slave station apparatus at a transmission timing that is transmitted.   When the slave station device is in the power saving mode, the slave station device transmits data to the slave station device in a time zone in which the slave station device is estimated to be in an active period based on the estimated start time. The master station apparatus according to claim 23.   A plurality of the slave station devices are provided, and when the uplink data received from the slave station device is generated, the sleep time is adjusted based on the estimated start time so that the active periods do not overlap. The master station device according to claim 25.   When there are a plurality of slave station devices and the rate of downlink data to be transmitted to the slave station devices is less than a certain value, the active period overlaps among the plurality of slave station devices and is transmitted to the slave station devices 27. The master station apparatus according to claim 25 or 26, wherein the sleep time is controlled so that the active periods do not overlap when a downlink data rate is equal to or greater than the predetermined value. A plurality of the slave station devices,
The transmission timing of a control signal instructing the start of the power saving mode is controlled so that the active periods do not overlap among the plurality of slave station devices. The master station device described. A master station device connected by an optical communication path to a slave station device having a power saving mode that periodically repeats a sleep period in which the optical receiver is in a power saving state and an active period in which the optical receiver is temporarily activated. There,
A receiving unit for receiving data to be transmitted to the slave station device;
A power saving control unit that calculates a sleep time that is a length of the sleep period in which the data can be received based on the data;
With
When the data is received by the receiving unit, a signal instructing to set the sleep time calculated by the power saving control unit as the sleep time of the power saving mode is transmitted to the slave station device. Master station device. A sleep period in which an optical transmitter connected to the master station apparatus through an optical communication path and performing transmission processing to the master station apparatus is in a power saving state and an active period in which the optical transmitter is temporarily activated are periodically A control device in a slave station device having a repeated power saving mode,
A power saving control unit that calculates a sleep time, which is a length of the sleep period in which the data can be transmitted, based on data transmitted to the master station device;
With
When the reception unit receives the data, the length of the sleep period is set to the sleep time calculated by the power saving control unit, and the data is transmitted to the master station device during the active period. Control device. A sleep period in which an optical receiver connected to the master station apparatus through an optical communication path and performing processing for receiving data transmitted from the master station apparatus is in a power saving state, and an active period in which the receiver is temporarily activated Is a control device in a slave station device having a power saving mode that periodically repeats,
Based on the data, a power saving control unit that calculates a sleep time that is the length of the sleep period in which the data can be received;
With
A control device that transmits the sleep time to the master station device. In a master station device connected by an optical communication path to a slave station device having a power saving mode that periodically repeats a sleep period in which an optical transmitter is in a power saving state and an active period in which the optical transmitter is temporarily activated A control device,
A power saving control unit that calculates a sleep time that is a length of the sleep period in which the data can be transmitted based on data transmitted to the slave station device;
With
When the data is received by the receiving unit, a signal instructing to set the sleep time calculated by the power saving control unit as the sleep time of the power saving mode is transmitted to the slave station device. Control device. Optical communication with a slave station device having a power saving mode that periodically repeats a sleep period in which the optical receiver and the optical transmitter are in a power saving state and an active period in which the optical receiver and the optical transmitter are temporarily activated A control device in a master station device connected by a road,
Based on the data, a power saving control unit that calculates a sleep time that is the length of the sleep period in which the slave station device can receive the data;
With
A control device that transmits a signal instructing to set the sleep time calculated by the power saving control unit as a sleep time in the power saving mode to the slave station device. A master station, a sleep period in which the optical transmitter connected to the master station by an optical communication path and performing transmission processing to the master station is in a power saving state, and an active that temporarily activates the optical transmitter An optical communication system comprising a slave station device having a power saving mode that periodically repeats a period,
The slave station device is
A receiving unit for receiving data to be transmitted to the master station device;
A power saving control unit that calculates a sleep time that is a length of the sleep period in which the data can be transmitted based on the data;
With
When the reception unit receives the data, the length of the sleep period is set to the sleep time calculated by the power saving control unit, and the data is transmitted to the master station device during the active period. Optical communication system. A sleep period in which a master station device is connected to the master station device through an optical communication path, and an optical receiver for receiving data transmitted from the master station device is in a power saving state, and temporarily the receiver A slave station device having a power saving mode that periodically repeats an active period for starting
The slave station device is
Based on the data, a power saving control unit that calculates a sleep time that is the length of the sleep period in which the data can be received;
With
An optical communication system, wherein the sleep time is transmitted to the master station device. A slave station device having a power saving mode that periodically repeats a sleep period in which the optical transmitter is in a power saving state and an active period in which the optical transmitter is temporarily activated, and is connected to the slave station device through an optical communication path An optical communication system comprising:
The master station device is
A receiving unit for receiving data to be transmitted to the slave station device;
A power saving control unit that calculates a sleep time that is a length of the sleep period in which the data can be transmitted based on the data;
With
When the data is received by the receiving unit, a signal instructing to set the sleep time calculated by the power saving control unit as the sleep time of the power saving mode is transmitted to the slave station device. Optical communication system. A slave station device having a power saving mode that periodically repeats a sleep period in which an optical receiver and an optical transmitter are in a power saving state and an active period in which the optical receiver and the optical transmitter are temporarily activated; An optical communication system comprising a master station device connected to a slave station device by an optical communication path,
The master station device is
Based on the data, a power saving control unit that calculates a sleep time that is the length of the sleep period in which the slave station device can receive the data;
With
An optical communication system, wherein a signal instructing to set a sleep time calculated by the power saving control unit as a sleep time in the power saving mode is transmitted to the slave station device. A master station, a sleep period in which the optical transmitter connected to the master station by an optical communication path and performing transmission processing to the master station is in a power saving state, and an active that temporarily activates the optical transmitter A power saving control method in an optical communication system comprising a slave station device having a power saving mode that periodically repeats a period,
A reception step in which the slave station device receives data to be transmitted to the master station device;
A sleep time calculating step in which the slave station device calculates a sleep time that is a length of the sleep period in which the data can be transmitted based on the data;
When the slave station apparatus receives the data, a transmission step of setting the length of the sleep period to the sleep time calculated in the sleep time calculation step and transmitting the data to the master station apparatus during the active period When,
A power saving control method comprising: A sleep period in which a master station device is connected to the master station device through an optical communication path, and an optical receiver for receiving data transmitted from the master station device is in a power saving state, and temporarily the receiver A power saving control method in an optical communication system comprising: a slave station device having a power saving mode that periodically repeats an active period for starting
A sleep time calculating step in which the slave station device calculates a sleep time, which is a length of the sleep period in which the data can be received, based on the data;
The slave station device transmits the sleep time to the master station device; and
A data transmission step in which the master station device estimates an active period in the slave station device based on the sleep time, and transmits the data to the slave station device in the estimated active period;
A power saving control method comprising: A slave station device having a power saving mode that periodically repeats a sleep period in which the optical transmitter is in a power saving state and an active period in which the optical transmitter is temporarily activated, and is connected to the slave station device through an optical communication path A power-saving control method in an optical communication system comprising:
A reception step in which the master station device receives data to be transmitted to the slave station device;
A sleep time calculating step in which the master station device calculates a sleep time that is a length of the sleep period in which the data can be transmitted, based on the data;
A transmitting step of transmitting, to the slave station device, a signal instructing to set the sleep time calculated in the sleep time calculating step as the sleep time of the power saving mode when the master station device receives the data; ,
A setting step in which the slave station device sets a sleep time in the power saving mode based on the signal;
A power saving control method comprising: A slave station device having a power saving mode that periodically repeats a sleep period in which an optical receiver and an optical transmitter are in a power saving state and an active period in which the optical receiver and the optical transmitter are temporarily activated; A power-saving control method in an optical communication system comprising a master station device connected to a slave station device by an optical communication path,
A sleep time calculating step in which the master station device calculates a sleep time, which is a length of the sleep period in which the slave station device can receive the data, based on the data;
A transmitting step of transmitting a signal to the slave station device to instruct the slave station device to set the sleep time calculated in the sleep time calculation step as the sleep time of the power saving mode;
A setting step in which the slave station device sets a sleep time in the power saving mode based on the signal;
A power saving control method comprising:

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