JP2014007707A - Method for power saving in subscriber side optical communication device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To save power with a small delay while suppressing large reduction of band use efficiency even when frequent communication occurs.SOLUTION: A time to transmit a signal from an OLT 104 to each ONU 101 is determined in advance, so as to be reported to the ONU 101. From information reported from the OLT 104, the ONU 101 grasps a transmission time of a downlink signal destined to an own unit and a transmission permission time of an uplink signal. In a time other than the transmission time of the downlink signal destined to the own unit, a receiver unit is made to sleep, and in a time other than the transmission permission time of the uplink signal, a transmitter unit is made to sleep. Thus, a power saving effect is obtained even when frequency communication occurs.

Description

  The present invention relates to a power saving method for a subscriber-side optical communication device in a passive optical network in which a station-side optical termination device and a plurality of subscriber-side optical communication devices are connected.

  In an optical access system, a passive optical network (PON) system in which a station-side optical terminal (OLT) and a plurality of subscriber-side optical communication units (Optical Network Unit: ONU) are connected is widely used. doing.

  In the PON system, in order for a plurality of ONUs to communicate with the OLT, multiple access is realized by dividing time. Specifically, as described in Non-Patent Document 1, a control protocol called MPCP (Multi-Point Control Protocol) is defined.

  As a method for reducing the power consumption of the ONU in the PON system, there is an ONU sleep technology. The ONU sleep technology reduces power consumption by causing each functional unit inside the ONU to enter a sleep mode when there is no data. Non-Patent Document 2 defines a sleep method called “Dozing” and “Cyclic sleep” as a power saving technique in an optical access system.

  Dosing realizes a reduction in power consumption by shifting the ONU transmission unit to a sleep mode when there is no uplink data to be transmitted from any ONU to the OLT. In Dosing, the occurrence of uplink data is monitored, and when the uplink data is confirmed, the transmitter is returned to the normal mode and communication is resumed.

  Cyclic sleep implements a reduction in power consumption by shifting the ONU transmission / reception unit to a sleep mode when both uplink data and downlink data to be transmitted from an OLT to an arbitrary ONU do not exist. When the ONU receives downstream data for the ONU from the upper network while the ONU is sleeping, the OLT accumulates it in a queue. The ONU periodically returns to the normal mode and inquires of the OLT whether or not downlink data is stored, thereby enabling signal transmission / reception while reducing power consumption of the transmission / reception unit.

IEEE Std 802.3-2008 ITU-T Recommendation G. 987.3

  Power saving techniques such as Dosing and Cyclic sleep defined in Non-Patent Document 2 achieve power consumption reduction by putting a transmission unit or a reception unit to sleep when there is no data. Since these sleep technologies determine whether or not to sleep by using the presence or absence of data as a trigger, in a situation where communication frequently occurs, sleep cannot be entered and a sufficient power saving effect cannot be obtained. In a situation where many terminals are connected to one ONU, communication frequently occurs, and such a problem becomes remarkable.

  In order to obtain a power saving effect even when communication frequently occurs, a method of forcibly sleeping regardless of the presence or absence of data is effective. Even when communication frequently occurs, a certain power-saving effect can be obtained by accumulating in a queue and forcibly sleeping. However, if the conventional sleep technique is applied at this time, an increase in delay becomes a problem.

  An object of the present invention is to reduce power consumption with low delay while suppressing a significant decrease in bandwidth utilization efficiency even when communication frequently occurs.

  In order to achieve the above object, in the present invention, a time for transmitting a signal from the OLT to each ONU is determined in advance and notified to the ONU. The ONU grasps the transmission time of the downlink signal addressed to itself and the transmission permission time of the uplink signal from the information notified from the OLT. By causing the receiving unit to sleep other than the transmission time of the downlink signal addressed to itself, and causing the transmission unit to sleep other than the transmission permission time of the uplink signal, a power saving effect is obtained even when communication frequently occurs.

  The method for reducing power consumption of a subscriber-side optical communication apparatus according to the present invention includes the power consumption of the subscriber-side optical communication apparatus in a passive optical network in which a station-side optical termination apparatus and a plurality of subscriber-side optical communication apparatuses are connected. A downlink signal accumulation step for accumulating a downlink signal to be transmitted from the station side optical termination device to the subscriber side communication device in the station side optical termination device, and a scheduled transmission time of the accumulated downlink signal. Downlink signal transmission information including the downlink signal transmission information notifying step from the station side optical termination device to the subscriber side communication device, and at the scheduled transmission time of the downlink signal notified by the downlink signal transmission information At the time other than the scheduled transmission time of the downlink signal notified by the downlink signal transmission information, the subscriber side communication device receives the downlink signal when the receiving unit in the subscriber side communication device becomes the normal operation mode. Has a downlink signal reception step of receiving unit in the serial subscriber communication device is short sleep mode, in this order.

  In the subscriber-side optical communication apparatus power consumption reduction method according to the present invention, the downlink signal transmission information may include each transmission start time of each downlink signal.

  In the power consumption reduction method for a subscriber-side optical communication apparatus according to the present invention, the downlink signal transmission information may include a time from a downlink signal transmission end time to a next downlink signal transmission start time.

  In the power consumption reduction method for a subscriber-side optical communication apparatus according to the present invention, the downlink signal transmission information may include information indicating presence / absence of a downlink signal.

  The method for reducing power consumption of a subscriber-side optical communication apparatus according to the present invention is a power consumption of the subscriber-side optical communication apparatus in a passive optical network in which a station-side optical termination apparatus and a plurality of subscriber-side optical communication apparatuses are connected. The uplink signal transmission information including the transmission permission time of the uplink signal to be transmitted from the subscriber side optical communication device to the intra-station optical termination device is transmitted from the intra-station optical termination device to the subscriber side. An uplink signal transmission information notifying step for notifying to the optical communication device, and the transmission side in the subscriber side communication device becomes a normal operation mode during the uplink signal transmission permission time notified by the uplink signal transmission information. The communication device transmits an uplink signal, and the transmission unit in the subscriber-side communication device enters the short sleep mode at a time other than the transmission permission time of the uplink signal notified by the uplink signal transmission information. Ri has a signal transmission step, in this order.

  A station-side optical termination device according to the present invention is a station-side optical termination device connected to a plurality of subscriber-side optical communication devices, and a downlink signal transmitted from the station-side optical termination device to the subscriber-side communication device , A downlink signal transmission information determination unit that determines a scheduled transmission time of the downlink signal stored in the queue, and downlink signal transmission information indicating the time obtained by the downlink signal transmission information determination unit, A downlink signal transmission information notification unit for notifying the subscriber side communication device.

  A subscriber-side optical communication apparatus according to the present invention includes: a receiving unit that receives downlink signal transmission information indicating a transmission time of a downlink signal from a station-side optical terminal to a subscriber-side optical communication apparatus; and the downlink signal transmission The downlink signal reception scheduled time transmitted at the downlink signal transmission time indicated by the information supplies power to the receiving unit, and the times other than the downlink signal reception scheduled time supply power to the receiving unit. And a control unit that stops.

  The above inventions can be combined as much as possible.

  According to the present invention, it is possible to reduce power consumption in the subscriber side communication device even when communication frequently occurs.

1 is a basic configuration diagram of a passive optical network. 6 is an example of a time chart in the first and second embodiments. 6 is an example of an operation flow of an OLT transmission unit according to the first embodiment. 6 is an example of an OLT downlink signal transmission information generation procedure according to the first embodiment. It is an example of the operation | movement flow of the ONU receiving part of Embodiment 1-3. 6 is an example of a downlink signal reception procedure of an ONU reception unit according to the first embodiment. 6 is an example of a short sleep procedure of an ONU receiving unit according to the first embodiment. It is an example of the operation | movement flow of the ONU transmission part of Embodiment 1-3. 10 is an example of a procedure for generating downlink signal transmission information of an OLT according to the second embodiment. 6 is an example of a signal reception procedure of an ONU reception unit according to the second embodiment. 6 is an example of a short sleep procedure of an ONU receiving unit according to the second embodiment. It is an example of the mode of the power mode in the ONU receiving part of Embodiment 3. It is an example of the OLT downlink signal transmission information generation procedure of Embodiment 3. 10 is an example of a signal reception procedure of an ONU reception unit according to the third embodiment. 10 is an example of a short sleep procedure of an ONU receiving unit according to a third embodiment.

  Embodiments of the present invention will be described with reference to the accompanying drawings. The embodiments described below are examples of the present invention, and the present invention is not limited to the following embodiments. In addition, in this specification and drawing, the component of the same code | symbol shall show the mutually same thing. Each embodiment can be combined as much as possible. Each embodiment can also be combined with a conventional sleep technology such as “Dozing” or “Cyclic sleep” defined in Non-Patent Document 2.

(Embodiment 1)
This embodiment is a basic embodiment of the present invention, and on the basis of information notified from the OLT, each ONU autonomously sleeps in a time zone in which no downlink signal is received or an uplink signal is not transmitted. It is an example. The upstream signal is a generic term for signals transmitted from the ONU including upstream data to the OLT, and the downstream signal is a generic term for signals transmitted from the OLT including downstream data to the ONU.

  FIG. 1 shows a configuration diagram of a passive optical network to which a subscriber-side optical communication apparatus (hereinafter abbreviated as “ONU”) 101 of the present invention is connected. As shown in FIG. 1, the present invention is a point-to-multipoint in which a station side optical terminator (hereinafter abbreviated as “OLT”) 104 and a plurality of ONUs 101 are connected via an optical splitter 102 and an optical fiber 103. Type communication system is assumed. In the point-to-multipoint communication system described in this embodiment, at least one of the plurality of ONUs to be connected is the ONU 101 of this embodiment.

FIG. 2 is a time chart showing how messages are exchanged between the OLT 104 and the ONU 101 and the power mode of the transmission / reception unit in the ONU 101 according to this embodiment. The receiving unit of the ONU 101 is in the normal mode (displayed as “ON” in the figure) only while receiving the downlink signal DL addressed to itself from the OLT 104, and the other time zones Δt _{D1 to} Δt _{DN + 1} are in the short sleep mode. ("OFF" is displayed in the figure). The transmission unit is in the normal mode only while transmitting the uplink signal UL, and the other time zones Δt _{U1 to} Δt _{UM + 1} are in the short sleep mode.

The OLT 104 according to the present embodiment transmits the transmission start time of the downlink signal DL to the GATE 201 that is an MPCP message for notifying the transmission permission time of the uplink signal UL to each ONU 101. The transmission permission time of the uplink signal UL is the transmission start time and the transmission continuation time of the uplink signals 221 to 22M. The transmission start time of the downlink signal DL includes the transmission start times t _{D1 to} t _{DN of} all the downlink signals 211 to 21N transmitted until the next GATE 202 transmission, and the transmission start time t _G2 of the next GATE 202. .

  Note that the transmission start time of the downlink signal DL can be transmitted at a different timing as a message different from GATE. In this case, the OLT 104 notifies each ONU 101 at a predetermined time, and notifies the message including the transmission start time and the next notification time of all downlink signals DL transmitted until the next notification. To do. Alternatively, the transmission start time of the next downlink signal DL to the ONU 101 can be determined every time the downlink signal DL is transmitted, and notified together with the transmission of the downlink signal DL.

  The OLT 104 according to this embodiment includes a queue for downlink data to the ONU 101. After receiving the downlink data addressed to the ONU 101 from the upper network 112, the OLT 104 temporarily stores the data in the queue.

  The power consumption reduction method for the subscriber-side optical communication apparatus includes a downlink signal accumulation step, a downlink signal transmission information notification step, and a downlink signal reception step in order to reduce power consumption during downlink signal transmission. In the downstream signal accumulation step, the queue in the OLT 104 temporarily accumulates downstream signals. In the downlink signal transmission information notification step, the OLT 104 notifies the ONU 101 of downlink signal transmission information including the scheduled transmission time of the downlink signal. In the downlink signal reception step, the receiving unit in the ONU 101 enters the normal operation mode to receive the downlink signal at the scheduled transmission time of the downlink signal notified by the downlink signal transmission information, and transmits the downlink signal notified by the downlink signal transmission information. The receiving unit in the ONU 101 enters the short sleep mode at a time other than the scheduled time.

  FIG. 3 shows an operation flow in the transmission unit of the OLT 104 of the present embodiment. The processing in the OLT 104 includes a downlink signal transmission information generation procedure and a GATE transmission processing procedure (S301 to S303) for determining a downlink signal transmission time for each ONU 101, and downlink data transmission for transmitting downlink data in accordance with the determined transmission time. It is roughly divided into processing procedures (S304 to S305). A downlink signal transmission information generation procedure and a GATE transmission processing procedure are executed in the downlink signal transmission information notification step, and a data transmission processing procedure is executed in the downlink signal reception step.

FIG. 4 shows details of the downlink signal transmission information generation procedure in the OLT 104 of this embodiment. Downlink signal transmission information generation procedure is performed in accordance with the GATE201 transmission time _{t G1.} By the downlink signal transmission information determination unit, the OLT 104 determines transmission start times t _{D1 to} t _DN and t _G2 of all downlink signals until the GATE 202 is transmitted to the ONU 101 (S401). Thereafter, the downlink signal transmission information notifying unit places the downlink signal transmission start times t _{D1 to} t _DN and t _G2 on the GATE 201 as downlink signal transmission information (S402), and notifies each ONU (S303). The determination of the downlink signal transmission start time (S401) is dynamically determined based on the amount of data accumulated in the downlink data queue of the OLT 104, but is fixedly determined regardless of the accumulated data amount. Also good. Thereafter, the OLT 104 transmits GATE 201 to the ONU 101.

  The ONU 101 of this embodiment includes a receiving unit that receives a signal from the OLT 104, a transmitting unit that transmits a signal to the OLT 104, and a control unit that controls the power mode of the receiving unit and the transmitting unit. The ONU 101 of the present embodiment includes two types of power modes, a normal mode and a short sleep mode, in each of the reception unit and the transmission unit. The normal mode represents a state in which the transmission unit transmits an uplink signal in accordance with a transmission permission time from the OLT 104, or a state in which a reception unit receives a downlink signal addressed to itself. The short sleep mode represents a state in which power consumption is reduced when transmission of an upstream signal is not permitted or when a downstream signal is not addressed to itself. Each of the reception unit and the transmission unit performs a short sleep for some or all of the functional units.

  FIG. 5 shows an operation flow in the receiving unit of the ONU 101 of this embodiment. The processing in the receiving unit of the ONU 101 is roughly divided into a downlink signal receiving procedure (S501) for receiving a signal and a receiving unit short sleep procedure (S502) for reducing power consumption without receiving a signal.

FIG. 6 shows details of the downlink signal reception procedure in the receiving unit of the ONU 101 of this embodiment. The ONU 101 includes a reception end determination unit for a signal addressed to itself, and receives only a signal addressed to itself (S601). Determine the message type of the received downlink signal (S602), if GATE201, downlink signals transmitted as the reception start time of the transmission permitted time and the downlink signal of the uplink signal information _t D1 _{~t DN,} updates the _{t G2} (S603 ~ S604). If the received downlink signal is data 211 to 212, data reception processing is performed (S605). The reception end determination is determined using the destination information included in the signal, but the OLT 104 can also explicitly notify using a flag indicating the end of transmission.

FIG. 7 shows details of the receiving unit short sleep procedure in the receiving unit of the ONU 101 of the present embodiment. The reception unit short sleep procedure is executed after reception of the downlink signal. The ONU 101 determines the return time from the reception start times t _D1 to t _DN and t _{G2 of} the downlink signal notified from the OLT 104 to the normal mode (S701). Thereafter, when it is determined that the transition to the short sleep mode is possible (S702), the reception unit shifts to the short sleep mode (S703). Using the internal time of the ONU 101 and a timer, the receiving unit is returned to the normal mode according to the return time (S704 to S705).

The transition time for shifting to the short sleep mode and the recovery time for returning to the normal mode of each receiving unit are different. The ONU 101 determines whether or not the short sleep can be executed according to the function unit having the longest sleep transition time and return time (S702). It is also possible to select a receiver that can perform a short sleep between the short sleep start time and the next downlink signal reception time.
The ONU 101 receives the downlink signal after returning the receiving unit to the normal mode.

  The ONU 101 of this embodiment includes a queue and a transmission unit for uplink data to the OLT 104. After receiving the upstream data addressed to the OLT 104 from the lower network 111, the ONU 101 temporarily stores the data in the queue.

  The power consumption reduction method for the subscriber-side optical communication apparatus includes an uplink signal accumulation step, an uplink signal transmission information notification step, and an uplink signal transmission step in order to reduce power consumption during uplink signal transmission. In the upstream signal accumulation step, the queue in the ONU 101 temporarily accumulates upstream signals. In the uplink signal transmission information notifying step, uplink signal transmission information including an uplink signal transmission permission time is notified from the OLT 104 to the ONU 101. In the uplink signal transmission step, the transmission unit in the ONU 101 enters the normal operation mode to transmit the uplink signal during the uplink signal transmission permission time notified by the uplink signal transmission information, and transmits the uplink signal notified by the uplink signal transmission information. The transmitter in the ONU 101 enters the short sleep mode at a time other than the permitted time.

  FIG. 8 shows the operation of the transmission unit of the ONU 101 of this embodiment using a flowchart. The ONU 101 transmits the uplink signal during the uplink signal transmission permission time notified from the OLT 104 (S801). After transmitting the uplink signal, the transmission unit shifts to the short sleep mode (S802). The ONU 101 returns the transmission unit to the normal mode in accordance with the transmission start time of the next uplink signal (S803 to S804). The transmission start time of the next uplink signal is updated when GATE 201 is received in the operation of the receiving unit (S603), and ONU 101 returns the transmitting unit to the normal mode according to the information.

(Embodiment 2)
The present embodiment is an example in which the ONU 101 autonomously sleeps the receiving unit in a time zone in which the ONU 101 does not receive the downlink signal by notifying the ONU 101 of the downlink signal transmission time intervals Δt _{D1 to} Δt _{DN + 1} from the OLT 104. A method of sleeping the transmission unit in a time zone during which no uplink signal is transmitted is the same as that in the first embodiment.

  The passive optical network assumed in the present embodiment has the configuration shown in FIG. Further, the operation flow of the OLT 104 transmission unit, the operation flow of the ONU 101 reception unit, and the operation flow of the ONU 101 transmission unit are respectively shown in FIGS. 3, 5, and 8 as in the first embodiment.

The OLT 104 according to the present embodiment transmits to the GATE 201 by adding a time Δt _{D1 to} Δt _{DN + 1} from the downlink signal transmission end time to the next downlink signal transmission start time. Note that this information can also be transmitted at a different timing as a message different from the GATE 201, as in the first embodiment.

FIG. 9 shows details of the downlink signal transmission information generation procedure in the OLT 104 of the present embodiment. The OLT 104 includes a downlink signal transmission information determination unit and a downlink signal transmission information notification unit. The OLT 104 uses the downlink signal transmission information determination unit to determine downlink signal transmission start times t _{D1 to} t _DN and t _G2 to the ONU 101 (S901). Thereafter, the downlink signal transmission information notification unit calculates the transmission time intervals Δt _{D1 to} Δt _{DN + 1} of each downlink signal (S902), puts them in the GATE as downlink signal transmission information (S903), and notifies each ONU (S303).

FIG. 10 shows details of the downlink signal reception procedure in the receiving unit of the ONU 101 of this embodiment. The difference from the first embodiment is that at the time of GATE reception, the downlink signal transmission information t _{D1 to} t _DN and t _G2 are updated as the downlink signal reception start time (S604), instead of the reception time interval Δt _{D1 to} Δt _{DN + 1} . (S1004) is at point.

FIG. 11 shows the details of the receiving unit short sleep procedure in the receiving unit of the ONU 101 of this embodiment. The ONU 101 determines the short sleep time from the reception time intervals Δt _{D1 to} Δt _{DN + 1 of} the downlink signal notified from the OLT 104 (S1101). Thereafter, when it is determined that the transition to the short sleep mode is possible (S1102), the reception unit shifts to the short sleep mode (S1103). Using the internal time of the ONU 101 and a timer, the receiver returns to the normal mode after the short sleep time has elapsed (S1104 to S1105).

  The ONU 101 determines whether or not the short sleep can be executed according to the functional unit having the longest sleep transition time and return time (S1102). It is also possible to select a receiver that can perform a short sleep between the short sleep start time and the next downlink signal reception time.

(Embodiment 3)
In this embodiment, the ONU 101 autonomously switches to the ONU 101 from the OLT 104 until the next GATE 202 whether or not there is downlink data to the ONU 101, so that the ONU 101 autonomously enters the short sleep mode when there is no downlink data. This is an example of returning to the normal mode before the next GATE 202 is received.

  The passive optical network assumed in the present embodiment has the configuration shown in FIG. Further, the operation flow of the OLT 104 transmission unit, the operation flow of the ONU 101 reception unit, and the operation flow of the ONU 101 transmission unit are respectively shown in FIGS. 3, 5, and 8 as in the first embodiment.

  FIG. 12 shows the exchange of messages between the OLT 104 and the ONU 101 of this embodiment and the state of the power mode of the receiving unit in the ONU 101 using a time chart. The transmission unit is the same as in the first embodiment. The ONU 101 refers to the GATEs 1201 to 1204 notified from the OLT 104 and maintains the normal mode when it is determined that there is downlink data transmission. When it is determined that there is no downlink data transmission, until the next scheduled GATE reception time Enters the short sleep mode.

FIG. 13 shows a downlink signal transmission information generation procedure in the transmission unit of the OLT 104 of this embodiment. The difference from Embodiment 1 is that, in the downlink signal transmission information determination unit, the downlink signal transmission start times t _{D1 to} t _DN and t _G2 are determined and added to the GATE as downlink signal transmission information (S401 to S402). In addition, the presence or absence of transmission of a downlink signal until the next GATE notification is added (S1301 to S1302).

FIG. 14 shows details of the downlink signal reception procedure in the receiving unit of the ONU 101 of this embodiment. The difference from the first embodiment is that, instead of updating the downlink signal transmission information t _{D1 to} t _DN and t _G2 as the downlink signal reception start time (S604), the downlink signal reception presence / absence information until the next GATE notification is updated. (S1404).

  FIG. 15 shows the details of the receiving unit short sleep procedure in the receiving unit of the ONU 101 in this embodiment. The ONU 101 determines whether or not a short sleep is possible based on the reception presence / absence information of the downlink signal until the next GATE reception (S1501). When the short sleep is possible, the ONU 101 calculates the return time to the normal mode based on the GATE transmission cycle notified in advance from the OLT 104 (S1502). Thereafter, the receiving unit shifts to the short sleep mode (S1503), and returns to the normal mode in accordance with the return time (S1504 to S1505). The GATE transmission cycle may be calculated empirically by the ONU 101 itself.

  The present invention can be applied to the information communication industry.

101: ONU
102: Optical splitter 103: Optical fiber 104: OLT
111: Lower network 112: Upper network

Claims (7)

A method for reducing power consumption of the subscriber-side optical communication device in a passive optical network in which a station-side optical termination device and a plurality of subscriber-side optical communication devices are connected,
Downlink signal accumulation step of accumulating the downlink signal transmitted from the station side optical termination device to the subscriber side communication device in the station side optical termination device;
Downlink signal transmission information notification step for notifying the subscriber side communication device of downlink signal transmission information including the scheduled transmission time of the accumulated downlink signal from the station side optical termination device;
At the scheduled transmission time of the downlink signal notified by the downlink signal transmission information, the receiving unit in the subscriber side communication device becomes a normal operation mode, and the subscriber side communication device receives the downlink signal, and the downlink signal transmission information A downlink signal reception step in which the receiving unit in the subscriber side communication device is in a short sleep mode at a time other than the scheduled transmission time of the downlink signal notified in
A method for reducing the power consumption of the subscriber-side optical communication apparatus.   The method for reducing power consumption of a subscriber-side optical communication apparatus according to claim 1, wherein the downlink signal transmission information includes each transmission start time of each downlink signal.   3. The power consumption reduction of the subscriber-side optical communication apparatus according to claim 1, wherein the downlink signal transmission information includes a time from a downlink signal transmission end time to a next downlink signal transmission start time. Method.   4. The method for reducing power consumption of a subscriber-side optical communication apparatus according to claim 1, wherein the downlink signal transmission information includes information indicating presence / absence of a downlink signal. A method for reducing power consumption of a subscriber-side optical communication device in a passive optical network in which a station-side optical termination device and a plurality of subscriber-side optical communication devices are connected,
Uplink signal transmission information for notifying the subscriber-side optical communication device of uplink signal transmission information including the transmission permission time of the uplink signal transmitted from the subscriber-side optical communication device to the intra-station optical termination device A notification step;
During the uplink signal transmission permission time notified by the uplink signal transmission information, the transmission unit in the subscriber-side communication device is in a normal operation mode and the subscriber-side communication device transmits an uplink signal, and the uplink signal transmission information An uplink signal transmission step in which the transmitter in the subscriber side communication device is in a short sleep mode at a time other than the transmission permission time of the uplink signal notified in
A method for reducing the power consumption of the subscriber-side optical communication apparatus. A station side optical termination device connected to a plurality of subscriber side optical communication devices,
A queue for accumulating downlink signals to be transmitted from the station side optical termination device to the subscriber side communication device;
A downlink signal transmission information determination unit that determines a transmission scheduled time of the downlink signal accumulated in the queue;
A downlink signal transmission information notifying unit for notifying the subscriber side communication device of downlink signal transmission information indicating the time obtained by the downlink signal transmission information determining unit;
A station-side optical terminator. A receiving unit for receiving downlink signal transmission information indicating a transmission time of the downlink signal from the station side optical terminal device to the subscriber side optical communication device;
The scheduled reception time of the downlink signal transmitted at the downlink signal transmission time indicated by the downlink signal transmission information supplies power to the receiving unit, and the time except the scheduled reception time of the downlink signal is sent to the receiving unit. A control unit for stopping the power supply of
A subscriber-side optical communication device.

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