JP2015170944A - OLT and power consumption reduction method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce power consumption of an OLT while keeping processing operation for uplink data from an ONU.SOLUTION: An OLT 10 includes: a band allocation unit 17 for allocating, for each ONU 2, a transmission permission time zone in which the ONU 2 can transmit uplink data to the OLT 10, to the ONU 2; and a sleep control unit 18 for halting, on the basis of each ONU 2's transmission permission time zone, the whole OLT 10 or a halt target composed of one or a plurality of modules,in the OLT 10, for performing signal processing on received uplink data.

Description

  The present invention relates to a PON system technique, and more particularly to a power consumption reduction technique for reducing power consumption of an OLT (Optical Line Terminal) used on a station side.

  A PON (Passive Optical Network) system is an example of a communication system in which a plurality of subscriber side devices are connected by sharing a part of a transmission path with a station side device. The PON system is composed of, for example, an OLT (Optical Line Terminal) that is a station-side device installed in a telecommunications carrier station, and an ONU (Optical Network Unit) that is a subscriber-side device installed in a user's house. One optical fiber connected to the OLT is branched by an optical splitter on the way, and connected to each of a plurality of ONUs. Thus, since one optical fiber is shared by a plurality of subscribers, there is an advantage that the cost can be reduced.

  In the PON system, the OLT schedules the transmission timing of the upstream data of each ONU so that the upstream signals from each ONU to the OLT do not collide with each other in the shared section of the optical fiber. The OLT determines the upstream data transmission start time and transmission permission time of each ONU and notifies each ONU. The ONU is allowed to transmit uplink data only during the transmission permission time from the transmission start time instructed by the OLT. In this way, the OLT can control the uplink data bandwidth in the optical fiber sharing section to be assigned to each ONU exclusively in a time division manner, so that signals from each ONU can communicate without colliding with each other. It seems to be.

  On the other hand, in recent years, with the advent of various communication services and the spread of smartphones, an increase in environmental load due to communication systems has become a problem. Therefore, in the PON system, in order to further reduce the environmental load, sleep control (hereinafter, abbreviated as ONU sleep) is proposed in which the ONU is shifted to the sleep mode when there is no transmission data (for example, Non-Patent Document 1). Etc.)

  ONU sleep is a method for reducing the power consumption of an ONU component by putting it in a sleep mode when there is no data to be transmitted through the ONU. In response to a report request (Gate) from the OLT, a bandwidth request is reported when the upstream data to be transmitted by the ONU is stored, and when there is no stored data, it is reported that there is no stored data. When there is accumulated data, uplink data is transmitted according to transmission permission (Gate) from the OLT. The ONU does not transition to a new sleep mode until transmission of accumulated data is completed. When there is no accumulated data, the sleep mode is entered in response to the sleep message from the OLT.

Japanese Patent Application No. 2001-23412

R. Kubo, J. Kani, Y. Fujimoto, N. Yoshimoto, and K Kumozaki, "Adaptive Power Saving Mechanism for 10 Gigabit Class PON Systems," IEICE Trans Comm., Vol.E-93-B, no.2, pp.280-288, 2010

  In such a conventional technique, when there is no data to be transmitted, the power consumption of the ONU can be reduced by suspending the ONU on the subscriber side. However, since the OLT on the station side always operates regardless of whether there is data to be transmitted, there is a problem that power consumption is not reduced.

  An object of the present invention is to solve such a problem, and an object of the present invention is to provide a power consumption reduction technique capable of reducing the power consumption of the OLT while maintaining a processing operation for upstream data from the ONU.

  In order to achieve such an object, the OLT according to the present invention includes a plurality of ONUs (Optical Network Units) connected to the optical splitter via individual optical fibers and optical fibers shared by these ONUs. The OLT is used in an optical communication system including an OLT (Optical Line Terminal) connected to the optical splitter, and the ONU is set for each ONU according to the transmission request amount notified from each OLT. Based on the bandwidth allocation unit that calculates and allocates a transmission permission time zone in which uplink data can be transmitted to the OLT from the OLT and the transmission permission time zone of each ONU, the entire OLT or the reception within the OLT A sleep control unit that pauses a pause target that includes one or more modules that perform signal processing on the uplink data.

  Further, in the configuration example of the OLT according to the present invention, the sleep control unit specifies a no-signal period in which the uplink data does not pass through the suspension target based on the transmission permission time zone, The time zone during which the suspension target is suspended is specified from the no-signal period.

  In addition, one configuration example of the OLT according to the present invention is any one of the first time after which the sleep control unit receives the upstream data received from any one of the ONUs and the first time after the exit of the sleep target. And the second time when the upstream data received from the ONU passes through the entrance of the suspension target, and the time zone from the first time to the second time is specified as the no-signal period of the suspension target It is what you do.

  In addition, in the above-described configuration example of the OLT according to the present invention, the sleep control unit includes a first time zone in which the upstream data does not pass through the entrance of the suspension target, and the upstream data is the suspension target. A second time zone that does not pass through the exit is calculated, and a time zone in which the first and second time zones overlap is specified as the no-signal period of the suspension target.

In addition, in one configuration example of the OLT according to the present invention, the sleep control unit determines the arrival time of the uplink data from the entrance of the suspension target to the reference point in order to identify the arrival time of the uplink data determined in the OLT. Let the passing time be ΔFs, let the passing time of the uplink data from the exit to be suspended to the reference point be ΔFe, and start at the reference point in the first transmission permission time period allocated immediately before the no-signal period When the time and time width are Ta and La, respectively, and the start time at the reference point in the second transmission permission time period allocated immediately after the no-signal period is Tb, the start of the no-signal period in the suspension target Time Tea and end time Tsb are expressed by the following equation: Tea = Ta + La−ΔFe
Tsb = Tb−ΔFs
This is what I asked for.

  In addition, one configuration example of the OLT according to the present invention is that the sleep control unit includes the no-signal period and a restart time required until the signal processing can be resumed after the pause target pauses the signal processing. According to the comparison result, whether or not to pause the suspension target is determined.

  Also, in one configuration example of the OLT according to the present invention, the sleep control unit is distributed and arranged for each suspension target, and based on the transmission permission time zone of each ONU notified from the band allocation unit, A no-signal period in which uplink data does not pass through the suspension target in the suspension target is specified, and a time zone in which the suspension target is suspended is specified from the non-signal period.

  In addition, the power consumption reduction method according to the present invention includes a plurality of ONUs (Optical Network Units) connected to the optical splitter via individual optical fibers, and the optical splitter via the optical fibers shared by these ONUs. A power consumption reduction method used in the OLT of an optical communication system including a connected OLT (Optical Line Terminal), wherein a bandwidth allocation unit transmits uplink data from the ONU to the OLT for each ONU. A bandwidth allocation step for allocating a transmission permission time zone that can be transmitted, and a sleep control unit, based on the transmission permission time zone of each ONU, signal the uplink data received in the entire OLT or in the OLT. A sleep control step of suspending a suspending target composed of one or a plurality of modules to be processed.

  According to the present invention, it is possible to pause the operation of the OLT on the station side during a period in which the uplink data from the ONU on each subscriber side does not reach, and to maintain the processing operation on the uplink data, while maintaining the power consumption of the OLT Can be reduced.

It is a block diagram which shows the structure of a general PON system. It is explanatory drawing which shows the scheduling function used with a PON system. It is a block diagram which shows the structure of OLT concerning 1st Embodiment. It is a sequence diagram which shows the bandwidth allocation operation | movement of OLT concerning 1st Embodiment. It is explanatory drawing which shows the passage timing of the upstream data in the module inside OLT. It is explanatory drawing which shows the calculation method of the passage time of the upstream data in each module. It is explanatory drawing which shows an unallocated time slot | zone. It is explanatory drawing which shows the passage timing of the upstream data in the module inside OLT including an unallocated time slot | zone. It is explanatory drawing which shows the calculation method of a no signal period. It is a timing chart figure which shows the operation | movement of the sleep control using a level signal. It is a timing chart figure showing operation of sleep control using a pulse signal. It is a block diagram which shows the structure of OLT concerning 2nd Embodiment.

Next, embodiments of the present invention will be described with reference to the drawings.
[First Embodiment]
First, a general PON system PX in which the station side device OLT 10 according to the first embodiment of the present invention is used will be described with reference to FIG. 1 and FIG. FIG. 1 is a block diagram showing a configuration of a general PON system. FIG. 2 is an explanatory diagram showing a scheduling function used in the PON system.

As shown in FIG. 1, in this PON system PX, ONUs 2 (ONU # 1 to ONU # N) are connected to user devices 1 (user devices # 1 to #N) via UNIs (User Network Interfaces), respectively. Connected with.
Each ONU 2 is commonly connected to one optical splitter 3 via an optical communication path, and this optical splitter 3 is further connected to one OLT 10.
In addition, a host device 4 is connected to the OLT 10 via an SNI (Service Node Interface). In addition, the host apparatus 4 is connected to a provider-side host network (service network) NW.

[Scheduling function]
Next, the scheduling function of the PON system will be described with reference to FIG. Here, three ONUs # 1, ONU # 2, and ONU # 3 are commonly connected to the optical splitter 3 as the ONU 2, and further, one optical fiber is shared from the optical splitter 3 to one OLT 10. A PON system PX is shown as an example.

The scheduling function is a function for designating the transmission timing of the uplink data packet from the OLT 10 to each ONU 2.
In FIG. 2, in the optical fiber shared section X between the splitter 3 and the OLT 10, the OLT 10 schedules the transmission timing so that upstream packets transmitted from the ONUs 2 to the OLT 10 do not collide with each other. Yes. Specifically, the OLT 10 performs scheduling so that the arrival times of the upstream data packets from the ONUs 2 to the OLT 10 do not overlap each other.

In the example of FIG. 2, a section from time T1 to time T1 + L1 is assigned to ONU # 1, a section from time T2 to T2 + L2 is assigned to ONU # 2, a section from time T3 to time T3 + L3 is assigned to ONU # 3, A section from time T4 to time T4 + L4 is assigned to ONU # 1.
The OLT 10 calculates the range of the transmission time from each ONU 2 so that the arrival time of the data packet from each ONU 2 falls within the range of the section assigned to each ONU 2, and notifies this to each ONU 2. As a result, each ONU 2 transmits an uplink data packet only within the time range notified from the OLT 10, so that the packet from each ONU 2 does not collide in the optical fiber shared section X and can be received by the OLT 10. become.

[Configuration of OLT]
Next, the configuration of the OLT 10 according to the present embodiment will be described with reference to FIG. FIG. 3 is a block diagram illustrating a configuration of the OLT according to the first embodiment.

  As shown in FIG. 3, the OLT 10 includes, as main functional units, an optical transceiver (TRx) 11, an FEC unit 12 that performs code processing such as error correction, and data in the order in which upstream packet signals from the ONU 2 are processed. Between the encryption unit 13 that performs packet encryption processing, the MPCP (Multi Point Control Protocol) unit 14 that controls the ONU 2 based on the PON protocol, the buffer unit 15 that stores upstream data and performs priority control, and the upper network NW An SNI unit 16 having a connection function is provided.

  In the present embodiment, some or all of these functional units are configured from modules that are units that can be suspended by power supply stop control. Specific configurations of this module include, for example, one IC, one circuit board, one circuit block capable of controlling power supply in a large-scale electronic circuit such as LSI, or “CPU + software”. Assumed. The functional unit and the module are not limited to a one-to-one relationship. For example, a plurality of functional units may be mounted on one module, or a single functional unit may be mounted on a plurality of modules. May be.

Further, the OLT 10 is provided with a band allocation unit 17 and a sleep control unit 18 as functional units that do not directly process uplink data.
The bandwidth allocating unit 17 calculates the transmission permission time zone of each ONU 2 based on the data amount to be transmitted notified from each ONU 2, that is, the transmission request amount, and the data from each ONU 2 based on these transmission permission time zones. And a function for determining the transmission schedule of the.

The sleep control unit 18 performs signal processing on the entire OLT 10 or the received uplink data in the OLT 10 based on the transmission permission time zone of each ONU 2 obtained by the band allocation unit 17. It has a function of suspending a pause target composed of modules.
More specifically, based on the transmission permission time zone of each ONU 2, a function for calculating a no-signal period during which uplink data from each ONU 2 does not pass through the suspension target, and among the suspension targets, When the signal period is longer than the time required for resuming the suspension target, the function has a function of instructing the suspension target during the non-signal period.

[Operation of First Embodiment]
Next, the operation of the OLT 10 according to the present embodiment will be described.
FIG. 4 is a sequence diagram illustrating the bandwidth allocation operation of the OLT according to the first embodiment. Here, as in FIG. 2, three ONUs # 1, ONU # 2, and ONU # 3 are commonly connected to the optical splitter 3 as the ONU 2, and one optical fiber is shared from the optical splitter 3. A PON system PX connected to two OLTs 10 is shown as an example. Here, a case will be described as an example where each module is a separate suspension target.

  In FIG. 4, each ONU 2 first writes the amount of data to be transmitted in a control packet called a report frame, that is, a transmission request amount, and transmits it to the OLT 10. The bandwidth allocation unit 17 of the OLT 10 allocates an upstream data bandwidth to each ONU 2 according to the transmission request amount from each ONU 2. Specifically, in the example of FIG. 4, as a range of arrival time for uplink data from each ONU 2, a section from time T1 to time T1 + L1 is assigned to ONU # 1, and a section from time T2 to T2 + L2 is assigned to ONU # 2. , A section from time T3 to time T3 + L3 is assigned to ONU # 3, and a section from time T4 to time T4 + L4 is assigned to ONU # 4.

  At this time, if the arrival time ranges assigned to the respective ONUs 2 are determined so as not to overlap, the upstream data from the respective ONUs 2 reach the OLT 10 without colliding with each other in the shared section X of the optical fiber. Here, various methods have been proposed for calculating the allocated bandwidth, but the present invention can be applied to any calculation method.

  Next, the bandwidth allocation unit 17 calculates a range of transmission times from each ONU 2 corresponding to the allocated arrival time range. Since the bandwidth allocation unit 17 measures the required time between the OLT 10 and the ONU 2 for each ONU 2, the transmission time at each ONU 2 can be calculated backward from the arrival time at the OLT 10 using this required time. . In this example, the transmission time range in ONU # 1 is the interval from time t1 to time t1 + L1, the transmission time range in ONU # 2 is the interval from time t2 to time t2 + L2, and the transmission time in ONU # 3. The range is calculated as a section from time t3 to time t3 + L3.

Thereafter, the bandwidth allocation unit 17 describes the range of these transmission times in a control packet called a Gate frame, and sends it to each ONU 2. In this example, the Gate frame describing the transmission start time t1 and the transmission permission time L1 is transmitted to the ONU # 1, the Gate frame describing the transmission start time t2 and the transmission permission time L2 is transmitted to the ONU # 2, and the transmission starts. A Gate frame describing time t3 and transmission permission time L3 is transmitted to ONU # 3.
In response to this, each ONU 2 transmits an uplink data packet only during each transmission time permitted from the OLT 10.
Based on such a procedure, the upstream data packet is transmitted from each ONU 2 to the OLT 10, so that the packet from each ONU 2 does not collide even in the portion sharing the optical fiber.

  In this way, the uplink data transmitted from each ONU 2 is received by the OLT 10 and sequentially passes through the internal modules. FIG. 5 is an explanatory diagram showing upstream data passage timing in a module inside the OLT. Here, the passage timing when the uplink data transmitted from the ONU 2 passes through the entrance of each module is shown.

In FIG. 2 and FIG. 4 described above, the allocation range of the arrival time to the OLT 10 has been described as T1 to T1 + L1, etc. In more detail, as shown in FIG. 5, the entrance of the MPCP unit 14 that performs PON protocol control is provided. It is easy to consider that the reference point P is used and the arrival time at the reference point P is determined as the arrival time at the OLT 10.
That is, based on the allocation amount to each ONU 2 determined by the bandwidth allocation unit 17, the range of the arrival time of the uplink data from the ONU # 1 at the reference point P is defined as T1 to T1 + L1, the uplink data from the ONU # 2 The range of arrival time is assigned as T2 to T2 + L2, and the range of arrival time of uplink data from ONU # 3 is assigned as T3 to T3 + L3.

  When the arrival time at the reference point P is determined, the time at which the upstream data passes through other modules in the OLT 10 is also uniquely determined. FIG. 6 is an explanatory diagram showing a method for calculating the passage time of upstream data in each module. Here, the calculation method of the passage time in the FEC unit 12 will be described as an example.

  First, the upstream data passing time from the FEC unit 12 entrance to the reference point (MPCP unit 14 inlet) P viewed from the upstream data is ΔFs, and the upstream data passing time from the FEC unit 12 outlet to the reference point P is ΔFe. To do. Here, since ΔFs and ΔFe are constants determined by the circuit configuration, when the arrival time at the reference point P is determined as T1, the passing time of the upstream data at the FEC unit 12 entrance and the FEC unit 12 exit is These are uniquely determined as T1-ΔFs and T1-ΔFe, respectively. Similarly, the passage time of each module other than the FEC unit 12 is uniquely determined from the arrival time at the reference point P.

On the other hand, depending on the content of bandwidth allocation to each ONU 2, there may occur an unallocated time zone in which no bandwidth is allocated to any ONU 2. FIG. 7 is an explanatory diagram showing an unallocated time zone.
In the example of FIG. 7, the uplink data has not arrived at the OLT 10 from any ONU 2 between the time T3 + L3 and the time T4, and this time zone becomes the unallocated time zone.
The present invention intends to save power by pausing in units of modules of the OLT 10 during such an unallocated time zone.

FIG. 8 is an explanatory diagram showing uplink data passage timing in a module inside the OLT including an unallocated time zone. In this example, at the time of arrival at the reference point P, an unallocated time zone in which no bandwidth is allocated occurs between time T3 + L3 and time T4.
Here, it is guaranteed that no upstream data comes from any ONU 2 during this unallocated time period. This period is determined by the result of the band allocation calculation performed in the OLT 10 by the band allocation unit 17 and the like, and the OLT 10 can know in advance that there is a period in which no band is allocated in this way.

Next, with reference to FIG. 9, the calculation operation of the no-signal period in the sleep control unit 18 will be described. FIG. 9 is an explanatory diagram illustrating a method for calculating a no-signal period.
First, let Wa be a transmission permission time zone (first transmission permission time zone) assigned immediately before the no-signal period NS to be calculated, and Wa start time at a reference point P determined at the entrance of the MPCP unit 14 and The time widths are Ta and La, the transmission permission time zone (second transmission permission time zone) assigned immediately after the no-signal period NS is Wb, and the Wb start time and time width at the reference point P are Tb. And Lb.

  Next, since the time when the last uplink data of Wa arrives at the reference point P is Ta + La, the time (first time) Tea when the uplink data of Wa passes through the FEC unit 12 exit is Tea = Ta + La−ΔFe. It is. Further, since the time when the first upstream data of Wb arrives at the reference point P is Tb, the time (second time) Tsb when the upstream data of Wb passes through the FEC unit 12 entrance is Tsb = Tb−ΔFs. Become.

Here, if Tsb> Tea, it can be seen that the time zone from time Tea to time Tsb is a non-signal period NS in which no uplink data passing through the FEC unit 12 exists.
Therefore, if the time width Tsb−Tea = {Tb− (Ta + La)} − (ΔFs−ΔFe) of the no-signal period NS is sufficiently long, the FEC unit 12 can be suspended.

  At this time, as another method of specifying the no-signal period, a time zone in which the uplink data does not pass through the FEC unit 12 entrance and a time zone in which the uplink data does not pass through the FEC unit 12 exit are calculated. The time zone in which these two time zones overlap may be specified as the no-signal period of the FEC unit 12.

  In the example of FIG. 9, since the time Ta + La to the time Tb is the no-signal period NSp at the reference point P, the point when ΔFs returns from NSp is the no-signal period (first time zone) NSs at the entrance of the FEC unit 12. , The time when ΔFe returns from NSp is the no-signal period (second time zone) NSe at the outlet of the FEC unit 12.

Here, the time widths of NSs and Nse are equal to NSp. The NSs end time Tsb is the time when ΔFs returns from the time Tb, and the NSe end time Teb is the time when ΔFe returns from the time Tb.
Therefore, the time in the time zone where NSs and Nse overlap can be obtained from the time width and time of NSs and Nse, and as a result, the no-signal period NS of the FEC unit 12 can be specified.

  On the other hand, when the FEC unit 12 is actually suspended during the no-signal period NS thus specified, a certain amount of time is required until the upstream signal processing can be resumed after the power is turned on again. The time required to resume the length is required. This requires time until the circuit is electrically stabilized after power is turned on, and time to return the saved data to a register that needs to save the stored contents during the pause. Because. How much start-up time is required is determined by circuit operation characteristics unique to the module, and the re-start time for determining whether or not it is possible to stop is determined for each module so as to include at least this re-start time.

  For this reason, if the no-signal period NS of the module is longer than the time required for restarting the module, it can be paused and then restarted. On the other hand, when the no-signal period NS is shorter than the resuming time, the uplink data passes before the module is completely activated from the dormant state, causing a malfunction.

  In the present embodiment, the sleep control unit 18 of the OLT 10 performs, based on the transmission permission time zone of each ONU 2 obtained by the band allocation unit 17, for each module, the upstream data from each ONU 2 does not pass through the module. The period NS is calculated, and when the no-signal period NS of the module is longer than the restart required time of the module among the modules, the module is instructed to stop the operation in the no-signal period NS.

  FIG. 10 is a timing chart showing an operation of sleep control using a level signal. Here, as an example of a sleep signal output from the sleep control unit 18 to the module, an example is shown in which a level signal indicating activation / pause by the H / L level is used.

  As shown in FIG. 10A, in any module, when the no-signal period NS to which no band is allocated is sufficiently long and is longer than the time required for restarting the module, the sleep control unit 18 At the time T11 when the no-signal period NS starts, the Sleep signal to the module is asserted (L level → H level). In response to this, the power control circuit in the module stops the power supply to each part of the module and stops the operation.

  Thereafter, the sleep control unit 18 negates the sleep signal to the module at least at a time T13 that is the time required for the module to complete the restart with respect to the end time T12 of the no-signal period NS. (H level → L level). In response to this, the power supply control circuit in the module restarts the power supply to each part in the module and starts activation.

  On the other hand, as shown in FIG. 10B, in any module, when the no-signal period NS is short and shorter than the time required for restarting the module, the sleep control unit 18 cannot stop the module. Is determined. For this reason, the Sleep signal is not asserted, and the module does not pause.

  FIG. 11 is a timing chart showing an operation of sleep control using a pulse signal. Here, an example is shown in which a pulse signal is used as a sleep signal and a wake signal for instructing the module to pause / start from the sleep control unit 18.

  As shown in FIG. 11A, in any module, when the no-signal period NS to which no band is allocated is sufficiently long and is longer than the time required for restarting the module, the sleep control unit 18 pauses the module. It is determined that it is possible, and at time T11 when the no-signal period NS starts, a Sleep signal including a pulse signal is output to the module. In response to this, the power control circuit in the module stops the power supply to each part of the module and stops the operation.

  After this, the sleep control unit 18 outputs a wake signal to the module at a time T13 that is at least the time required for the module to restart again, based on the end time T12 of the no-signal period NS. To do. In response to this, the power supply control circuit in the module restarts the power supply to each part in the module and starts activation.

  On the other hand, as shown in FIG. 11B, when the no-signal period NS is short in an arbitrary module and is shorter than the time required for restarting the module, the sleep control unit 18 cannot stop the module. Is determined. For this reason, the Sleep signal and the wake signal are not output, and the module does not pause.

[Effect of the first embodiment]
Thus, in the present embodiment, the bandwidth allocation unit 17 allocates a transmission permission time zone in which uplink data can be transmitted from the ONU 2 to the OLT 10 for each ONU 2, and the sleep control unit 18 Based on the transmission permission time zone, the entire OLT 10 or the suspension target composed of one or a plurality of modules for signal processing the received uplink data in the OLT 10 is suspended.
More specifically, the sleep control unit 18 specifies a no-signal period in which uplink data does not pass through the suspension target based on the transmission permission time period, and a time period during which the suspension target is suspended from the no-signal period. Is specified.

  As a result, the operation of the OLT 10 on the station side can be temporarily suspended during the period when the uplink data from the ONU 2 on each subscriber side does not reach, and the power consumption of the OLT 10 is reduced while maintaining the processing operation for the uplink data. It becomes possible.

  Further, in the present embodiment, the sleep control unit 18 receives the first time when the upstream data received from any ONU 2 passes through the exit to be paused, and the upstream data received from any ONU 2 for the first time A second time passing through the entrance of the suspension target, and specifying a time zone from the first time to the second time as the no-signal period of the suspension target, the no-signal period, and the suspension Depending on the result of comparison with the time required for restart until the signal processing can be resumed after the subject pauses the signal processing, it may be determined whether or not the suspension target can be paused.

  At this time, as a method of specifying the no-signal period, instead of the first and second times, the first time zone in which the uplink data does not pass through the entrance of the suspension target, and the upstream data is the suspension target A second time zone that does not pass through the exit may be calculated, and a time zone in which the first and second time zones overlap may be specified as the no-signal period of the suspension target.

  Thereby, even when a plurality of suspension targets are provided in the OLT 10, it is possible to accurately identify the no-signal period for each suspension target, and to resume processing that may occur when the suspension target is suspended during the identified no-signal period It is possible to determine whether or not to pause in consideration of the influence on the operation, and it is possible to realize a very stable processing operation even when the suspension target is suspended.

[Second Embodiment]
Next, an OLT 10 according to the second embodiment of the present invention will be described with reference to FIG. FIG. 12 is a block diagram illustrating a configuration of the OLT according to the second embodiment.
This embodiment is different from the first embodiment in that the sleep control unit 18A is distributed in each sleep target. Here, a case will be described as an example where each module is a separate suspension target.

  That is, in this embodiment, the sleep control unit 18A is distributed in each module (pause target) of the optical transceiver (TRx) 11, the FEC unit 12, the encryption unit 13, the MPCP unit 14, and the buffer unit 15. Each sleep control unit 18A determines a no-signal period in which uplink data does not pass through the module based on the transmission permission time zone of each ONU 2 notified from the band allocation unit 17. It has a function of specifying and specifying a time zone during which the module is suspended from the no-signal period.

  At this time, as for the method for specifying the no-signal period in each module, as in the first embodiment, the next uplink data passes through the entrance of the module from the time when the uplink data passes through the exit of the module. What is necessary is just to specify until the time to do as a no-signal period. Alternatively, a time zone in which the time zone in which the uplink data does not pass through the entrance of the module and the time zone in which the uplink data does not pass through the exit of the module may be specified as the no-signal period.

  Thereby, each sleep control unit 18A, for example, only the upstream data passing time ΔFs from the entrance of the own module to the reference point which is the entrance of the MPCP unit 14 and the passing time ΔFs of the upstream data from the own module exit to the reference point. Is previously stored as fixed data, the no-signal period in the own module can be identified very easily based on the transmission permission time zone of each ONU 2 at the reference point notified from the band allocation unit 17.

[Effect of the second embodiment]
As described above, according to the present embodiment, the sleep control unit 18A is distributed for each suspension target, and the uplink data in the suspension target is based on the transmission permission time zone of each ONU 2 notified from the bandwidth allocation unit 17. Specifies a non-signal period during which the object does not pass through the suspension target, and specifies a time period during which the suspension target is suspended from the non-signal period.
Thus, each sleep control unit 18A only needs to specify the passage time of the upstream data at the entrance / exit of its own suspension target, and can simplify the process of specifying the no-signal period.

[Extended embodiment]
The present invention has been described above with reference to the embodiments, but the present invention is not limited to the above embodiments. Various changes that can be understood by those skilled in the art can be made to the configuration and details of the present invention within the scope of the present invention. In addition, each embodiment can be implemented in any combination within a consistent range.

  PX ... PON system, 1 ... user device, 2 ... ONU, 3 ... optical splitter, 4 ... host device, 5 ... host network, 10 ... OLT, 11 ... TRx, 12 ... FEC unit, 13 ... encryption unit, 14 ... MPCP 15, buffer unit, 16, SNI, 17 bandwidth allocation unit, 18 sleep control unit.

Claims (8)

A plurality of ONUs (Optical Network Units) connected to the optical splitter via individual optical fibers, and an OLT (Optical Line Terminal) connected to the optical splitters via optical fibers shared by these ONUs The OLT used in an optical communication system,
A bandwidth allocation unit that calculates and allocates a transmission permission time zone in which uplink data can be transmitted from the ONU to the OLT for each of these ONUs according to the transmission request amount notified from each OLT;
A sleep control unit that pauses a pause target composed of one or a plurality of modules that perform signal processing on the received uplink data in the entire OLT or in the OLT based on a transmission permission time zone of each ONU. OLT characterized by comprising. The OLT according to claim 1,
The sleep control unit identifies a no-signal period in which the uplink data does not pass through the suspension target based on the transmission permission time period, and identifies a time period during which the suspension target is suspended from the no-signal period OLT, characterized by The OLT according to claim 2,
The sleep control unit includes a first time at which uplink data received from any one of the ONUs passes through the exit to be paused, and uplink data received from any of the ONUs for the first time from the entrance to the pause target. And a second time passing through the second time, and a time zone from the first time to the second time is specified as the no-signal period of the suspension target. The OLT according to claim 2,
The sleep control unit includes a first time zone in which the uplink data does not pass through the suspension target entrance and a second time zone in which the uplink data does not pass through the suspension target exit. An OLT that calculates and identifies a time zone in which the first and second time zones overlap as the no-signal period of the suspension target. The OLT according to claim 2,
The sleep control unit sets ΔFs as the transit time of the uplink data from the entrance of the suspension target to a reference point in order to specify the arrival time of the uplink data determined in the OLT, and the reference from the exit of the suspension target Let the passing time of the upstream data up to a point be ΔFe, start time and time width at the reference point in the first transmission permission time period allocated immediately before the no-signal period be Ta and La, respectively, When the start time at the reference point in the second transmission permission time period allocated immediately after the period is Tb, the start time Tea and the end time Tsb of the no-signal period in the suspension target are expressed by the following expression Tea = Ta + La -ΔFe
Tsb = Tb−ΔFs
OLT characterized by being obtained by In the OLT according to any one of claims 2 to 5,
The sleep control unit determines whether or not the sleep target can be stopped according to a comparison result between the no-signal period and a restart time required until the signal processing can be restarted after the stop target temporarily stops the signal processing. OLT characterized by determining. The OLT according to claim 1,
The sleep control unit is distributed for each suspension target, and based on the transmission permission time zone of each ONU notified from the bandwidth allocation unit, the uplink data in the suspension target passes through the suspension target. An OLT characterized by identifying a no-signal period without a signal and identifying a time period during which the suspension target is suspended from the no-signal period. A plurality of ONUs (Optical Network Units) connected to the optical splitter via individual optical fibers, and an OLT (Optical Line Terminal) connected to the optical splitters via optical fibers shared by these ONUs A power consumption reduction method used in the OLT of an optical communication system,
A bandwidth allocation step in which a bandwidth allocation unit allocates, for each ONU, a transmission permission time zone in which uplink data can be transmitted from the ONU to the OLT;
Based on the transmission permission time zone of each ONU, the sleep control unit pauses the entire OLT or one or more modules that perform signal processing on the received uplink data in the OLT. A power consumption reduction method comprising: a sleep control step.

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