JP6639092B2 - Optical communication system - Google Patents

Description

  The present invention relates to an optical communication system using a passive optical network.

  In an optical communication system using a passive optical network (PON) in which an optical line terminal (OLT) and an optical network unit (ONU) are connected by an optical transmission line, an optical line terminal (OLT) and a subscriber side device (ONU). There has been proposed an ONU sleep mode in which an ONU is shifted to a sleep state in which power consumption is reduced by stopping functions of some circuits such as a transceiver of the ONU (for example, Non-Patent Document).

FIG. 1 shows an example of the sleep state. Transition to the sleep state is performed, for example, when monitoring the communication from the OLT to the ONU in OLT, it exceeds the sleep transition threshold i _th predetermined for sleep transition. When traffic occurs with the corresponding ONU as the transmission / reception destination, the state shifts to the active state. In the sleep mode that can be in the sleep state, the ONU repeats the activation state and the sleep state. As the sleep time Ts in the sleep state, as shown in FIG. 2, a predetermined value that is predetermined according to a service class or the like is used.

Ryogo Kubo, Jun-ichi Kani, Hirotaka Ujikawa, Takeshi Sakamoto, Yukihiro Fujimoto, Naoto Yoshimoto, and Hisaya Hadama, "Study and Demonstration of Sleep and Adaptive Link Rate Control Mechanisms for Energy Efficient 10G-EPON", J. OPT. COMMUN. NETW, VOL. 2, NO. 9, pp. 761-728, 2010

  In the case of an optical communication system as shown in FIG. 3 for controlling a communication network by transmitting and receiving a control signal and a sensor signal at regular communication intervals, for example, a control system via a passive optical network, the average delay time of the communication network is The delay compensator 93 is designed by prediction.

  In the above-mentioned ONU sleep, the ONU periodically goes into a sleep state. Therefore, in an optical communication system using a passive optical network, if a control signal and a sensor signal are transmitted and received at a constant communication interval, the average delay time of the communication network may significantly change depending on the communication interval. Specifically, when the communication interval is near an integral multiple of the sleep time Ts, the average delay time of the communication network changes significantly. For this reason, it is difficult to correctly predict the average delay time of the communication network, and there is a problem that it is necessary to redesign the sequential delay compensator depending on the communication interval.

  Accordingly, an object of the present invention is to prevent a significant change in the average delay time of a communication network in an optical communication system using a passive optical network.

  The present invention varies at least one of the sleep time and the sleep transition threshold.

More specifically, the optical communication system according to the present invention is an optical communication system using a passive optical network in which an optical line terminal and a subscriber side device are connected by an optical transmission line and data is transmitted and received at regular communication intervals. Te, sleep time for the subscriber unit to the sleep state to be different from a multiple of the communication distance, Ru varying the sleep time.
In the optical communication system according to the present invention, a sleep transition threshold for causing the subscriber device to transition to a sleep state may be further changed so that the sleep time is different from a multiple of the communication interval. Here, the sleep transition threshold is at least one of the communication interval, the bandwidth used by the subscriber device, the amount of data transmitted to the subscriber device, and the amount of data received from the subscriber device. It is determined using one.

Specifically, the optical line terminal according to the present invention is used in an optical communication system using a passive optical network in which the optical line unit and the optical network unit are connected by an optical transmission line and data is transmitted and received at a constant communication interval. a said station side apparatus is such that said sleep time for the subscriber unit to sleep is different from multiples of the communication distance, and a switching unit for varying the sleep time, the subscriber side the sleep time A sleep instructing unit for instructing the device.

In the optical line terminal according to the present invention, the switching unit may further change a sleep transition threshold value for transitioning the subscriber unit to a sleep state so that the sleep time is different from a multiple of the communication interval, and The unit may cause the subscriber device to indicate the sleep transition threshold. Here, the sleep transition threshold is at least one of the communication interval, the bandwidth used by the subscriber device, the amount of data transmitted to the subscriber device, and the amount of data received from the subscriber device. It is determined using one.
The optical line terminal according to the present invention further includes an observation unit that uses the sleep transition threshold to determine whether or not the subscriber side device may be put into a sleep state, and the sleep instruction unit includes the observation unit. When it is determined that the subscriber device can be put into the sleep state, a sleep instruction for instructing a transition to the sleep state may be sent to the subscriber device.

Specifically, the subscriber unit according to the present invention is an optical communication system using a passive optical network in which the station unit and the subscriber unit are connected by an optical transmission line and transmits and receives data at a constant communication interval. A switching unit that varies the sleep time so that a sleep time for putting at least some of the circuits included therein to a sleep state is different from a multiple of the communication interval. A sleep instructing unit for causing a sleep state.

In the subscriber device according to the present invention, the switching unit may further change a sleep transition threshold for transition to a sleep state so that the sleep time is different from a multiple of the communication interval. Here, the sleep transition threshold is at least one of the communication interval, the bandwidth used by the subscriber unit, the amount of data transmitted to the subscriber unit, and the amount of data received from the subscriber unit. It is determined using one.
In the subscriber device according to the present invention, using the sleep transition threshold, further comprises an observation unit that determines whether the subscriber device or the circuit may be put into a sleep state, the sleep instruction unit, If the observation unit determines that the subscriber device or the circuit may be put into the sleep state, the circuit may be put into the sleep state.

  According to the present invention, in an optical communication system using a passive optical network, a remarkable change in the average delay time of the communication network can be prevented.

4 shows an example of a sleep state. An example of the relationship between the related communication interval i _ave , sleep transition threshold value i _th, and sleep time Ts is shown. 1 shows an example of the configuration of an optical communication system, for example, a control system that performs control by transmitting and receiving a control signal and a sensor signal at fixed communication intervals via a passive optical network. 5 shows an example of an average delay time with respect to a communication interval. 4 illustrates an example of a relationship among a communication interval i _ave , a sleep shift threshold i _th, and a sleep time Ts according to the first embodiment. ₁₃ illustrates an example of a relationship between a communication interval i _ave , a sleep shift threshold i _th, and a sleep time Ts according to the second embodiment. ₁₃ illustrates an example of a relationship between a communication interval i _ave , a sleep shift threshold i _th, and a sleep time Ts according to the third embodiment. 13 illustrates a configuration example of an optical communication system according to a fourth embodiment. 17 shows a configuration example of an optical communication system according to a fifth embodiment. 13 shows a configuration example of an optical communication system according to a sixth embodiment. 17 shows a configuration example of an optical communication system according to a seventh embodiment.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The present invention is not limited to the embodiments described below. These embodiments are merely examples, and the present invention can be implemented in various modified and improved forms based on the knowledge of those skilled in the art. In the specification and the drawings, components having the same reference numerals indicate the same components.

The invention according to the present embodiment varies at least one of the sleep time Ts and the sleep transition threshold value i _th when performing ONU sleep in the optical communication system using the passive optical network. For example, it may be varied only sleep time Ts may be varied only threshold i _th of sleep transition, it may be varied both sleep time Ts and the sleep transition threshold i _th.

The invention according to this embodiment, since at least one of the sleep time Ts and the sleep transition threshold i _th varies, release the multiple of sleep from the communication distance of the ONU sleep time Ts, at the same time ONU92 and a sleep Prevent becoming. For this reason, the invention according to the present embodiment can avoid a situation in which the ONU 92 always delays the control signal and the sensor signal even when the control signal and the sensor signal arrive at the ONU 92 at regular intervals. Therefore, in the invention according to the present embodiment, it becomes difficult to design the delay compensator by estimating the average delay time of the communication network when the communication interval is near an integral multiple of the sleep time Ts of the ONU sleep. Can be solved.

  Here, the fluctuation is performed in a range in which the average delay time approaches a preferable value, the value may be changed continuously, the value may be changed intermittently, or the value may be changed randomly. Good. The order of variation is arbitrary.

As the sleep transition threshold value i _th , any value that can determine whether the ONU 92 may be put into the sleep state can be used. For example, at least one of a frame transmission / reception interval, a used band, and a queue length can be used. In the following embodiment, as an example, a case where the sleep transition threshold value i _th is a frame transmission / reception interval, that is, a communication interval will be described.

  In the following, the communication interval will be described, but from the communication interval, when the frame length is constant, the used bandwidth is divided by the communication interval, and the frame length is divided by the communication interval for inputting to the queue, The same applies to the used bandwidth and the queue length so that the frame length can be converted by subtracting the frame length divided by the queue output interval.

The subject that varies the sleep time Ts and the sleep shift threshold value i _th may be the OLT 91 alone, the ONU 92 alone, both the OLT 91 and the ONU 92, and the OLT 91 and the ONU 92 other than the OLT 91 and the ONU 92. It may be a configuration.

When the OLT 91 is the main component, the OLT 91 may notify the sleep time Ts when instructing the ONU 92 to sleep. The OLT 91 may also notify a sleep transition threshold value i _th when issuing a sleep instruction. Note that the sleep instruction of the OLT 91 may be a response to the sleep request from the ONU 92, or may be a response to the sleep request, not an answer to the sleep request, but a result of observation in the OLT 91 different from the response to the sleep request. . Further, when the ONU 92 is activated in the cyclic sleep mode or when the OLT 91 instructs the ONU 92 to be activated, the sleep time Ts and / or the sleep transition threshold value i _th may be notified. Good. Further, the OLT 91 may notify the ONU 92 of at least one of the sleep time Ts and the sleep transition threshold value i _th irrespective of a message related to sleep.

If ONU92 is mainly, ONU92, at the time of the sleep request to the OLT91, may also notify the sleep transition threshold _{i th.} Further, ONU92, when a response to a sleep instruction from OLT91, may be notified at least one of the sleep time Ts and the sleep transition threshold _{i th.} Further, the ONU 92 may notify the OLT 91 of at least one of the sleep time Ts and the sleep shift threshold value i _th irrespective of a message related to sleep.

In the case where the ONU 92 is the main body and the transmitter that transmits from the ONU 92 to the OLT 91 is in the sleep state, the OLT 91 need not be notified of the sleep transition threshold i _th .

If ONU92 the OLT91 is principal, ONU92 is similar to the case or if OLT91 the principal is a principal, may be notified to one from the other, sleep varying time Ts and the sleep transition threshold _{i th} The notification between the two may be omitted by sharing the calculation order of the change and the calculation formula of the value to be changed so that both are synchronized.

In addition to the ONU 92 and the OLT 91, information on an observation target such as a device that transmits data upstream of the OLT 91 or a device that controls the OLT 91 or a device that controls the OLT 91 is acquired and a sleep instruction is indirectly transmitted via the OLT 91 or the customer device. or component and that can be directly transmitted to ONU92, indirectly or directly components sleep varying time Ts and sleep transition threshold i _th that can be notified to at least one of ONU92 the OLT91 may be mainly .

(Embodiment 1)
In the present embodiment, a combination of a plurality of sleep times Ts is used instead of one sleep time Ts.

  This will be described with reference to FIG. Assume that the communication interval is 50 ms. Since the frame size is 1250 bytes, 0.2 Mbps (= 1250 [B] / 50 [ms]) in the figure corresponds to a communication interval of 50 ms. When the sleep time Ts is 50 ms, the average delay time is 47 ms. In the present embodiment, a plurality of values, for example, a combination of 50 ms and 60 ms is used for the sleep time Ts. In the case of 60 ms, the delay time is 25 ms because there is no influence of the delay due to sleep. Therefore, if 50 ms and 60 ms are used alternately, the average delay time approaches the center value of 25 ms, such as the sum of the average delay times of both (36 (= (47 + 25) / 2) ms).

  When the central value of the sleep time Ts is 50 ms, for example, 40 ms and 60 ms may be used at the same frequency, or 40 ms, 50 ms, and 60 ms may be used at the same frequency as the plurality of sleep times Ts.

  When a plurality of sleep times Ts are used in order, the sleep state is periodically set to the sum of the sleep times Ts. In this case, the change in the average delay time becomes large at a communication interval that is near an integral multiple of the sum of a plurality of sleep times Ts for one cycle using a plurality of values. For this reason, it is desirable to use a value that is less likely to be used as a fixed communication interval in the vicinity of an integral multiple of the sum of a plurality of sleep times Ts for one cycle. For example, in the example of FIG. 4, in the example shown in FIG. , Neighborhood is several kbps.

  For example, if the sleep time Ts switches from 50 ms to 60 ms → 50 ms → 60 ms, it is preferable that the sum of the sleep times Ts, 50 + 60 = 110 ms, does not become close to an integral multiple of the communication interval. If the sleep time Ts switches from 50 ms → 50 ms → 60 ms → 60 ms → 50 ms → 50 ms → 60 ms → 60 ms, it is preferable that 50 + 50 + 60 + 60 = 220 ms, which is the total time of the sleep times Ts, is not close to an integral multiple of the communication interval. .

  Also, in order to increase the sum of a plurality of values, it is desirable to use three or more values as the plurality of sleep times Ts. More preferably, it is desirable to generate a value used for the sleep time Ts by a random number. When using pseudo-random numbers, it is desirable that the time until the same value occurs is longer.

  Prop (st. = Rand.) Shown in FIG. 4 is an example of the average delay time when the sleep time Ts is generated by a pseudo random number. In this case, it can be seen that the average delay time is 25 ms regardless of the communication interval.

FIG. 5 shows an example of the relationship between the communication interval i _ave , the sleep transition threshold value i _th, and the sleep time Ts according to the present embodiment. The fluctuation range of the sleep time Ts (T _{max to} T _min ) is preferably in the vicinity of the reference sleep time, for example, about ± 25%, more preferably about ± 10% of the reference sleep time. It is desirable to make it. This is because the power saving effect decreases as the fluctuation of the sleep time Ts increases.

  The sleep time Ts may be set in advance with the values used in the ONU 92 and the OLT 91 and the order in which the values are changed, or a method of determining the sleep time Ts, for example, a pseudorandom number generation formula and a seed value may be set in advance. You may set it. Further, the OLT 91 and the ONU 92 may communicate and share.

  Also, an example has been described in which a plurality of values are selected based on 50 ms as the sleep time Ts, but the invention according to the present embodiment is not limited to this.

(Embodiment 2)
In the present embodiment, a plurality of sleep transition thresholds i _th are used instead of a plurality of sleep times Ts. Others are the same as the first embodiment. For example, it is desirable that the sleep transition threshold value i _th be determined by a random number.

FIG. 6 shows an example of the relationship between the communication interval i _ave , the sleep transition threshold value i _th, and the sleep time Ts according to the present embodiment. The fluctuation range of the sleep transition threshold value i _th (i _{max to} i _min ) is preferably in the vicinity of the reference sleep transition threshold value i _th . It is desirable that at least one of the plurality of values of the sleep transition threshold value i _{th be} a value smaller than an assumed communication interval. For example, it is desirable that i _th include a value near 0. This is because the effect is great when the communication interval for transmitting and receiving the control signal and the sensor signal is included in the fluctuation cycle of the sleep transition threshold value i _th .

The sleep transition threshold value i _th includes a value near 0, and if the communication interval is less than or equal to the communication interval, the sleep is entered at a timing different from that when the communication interval is equal, and there is an effect of shifting the sleep cycle and the traffic generation timing. Further, it is desirable that at least one of the plurality of values of the sleep transition threshold value i _{th be} a value larger than an assumed communication interval. When sleep transition threshold i _th is not less than the communication distance, the effect of shifting the generation timing of the sleep period and traffic in sleep at different times and equal to the communication distance.

In particular, if the value is twice or more the communication interval, traffic with delay due to sleep and traffic without delay with sleep occur. Furthermore, if the value is a value that is twice or more the communication interval and a value other than the vicinity of an integral multiple of the communication interval, the effect of shifting the timing is great. That is, when the random number fluctuates between the minimum value i _min and the maximum value i _max , the minimum value i _{min of the} random number is ≒ 0, and the maximum value i _max is a value equal to or more than the assumed communication interval and an integer of the communication interval A value other than near double is desirable.

(Embodiment 3)
In the present embodiment, in addition to the sleep time Ts, there are a plurality of sleep transition thresholds i _th . Others are the same as the first and second embodiments. For example, it is desirable that the sleep time Ts and the sleep transition threshold value i _th be determined by random numbers.

Prop (st. = Th. = Rand.) Shown in FIG. 4 is an example of the average delay time when the sleep time Ts and the sleep transition threshold value i _th are generated by pseudo random numbers. In this case, it can be seen that the average delay time is approximately 25 ms regardless of the communication interval.

FIG. 7 shows a relationship between the communication interval i _ave , the sleep transition threshold value i _th, and the sleep time Ts according to the present embodiment.

Preferred examples of the fluctuation range of the sleep time Ts and the sleep transition threshold value i _th are as described in the first and second embodiments. The fluctuation range (T _{max to} T _min ) of the sleep time Ts varies in the vicinity of each of the reference sleep time Ts and the sleep transition threshold value i _th , for example, about ± 25%, more preferably about ± 10%. It is desirable to make it.

Further, it is desirable that at least one of the plurality of values of the sleep shift threshold value i _th is a value smaller than the assumed communication interval i _ave . For example, it is desirable that i _th include a value near 0. The sleep transition threshold i _th includes a value near 0. This is because the effect is great when the communication interval is included in the fluctuation cycle of the sleep transition threshold i _th .

The sleep transition threshold value i _th includes a value near 0, and if the communication interval is less than or equal to the communication interval, the sleep is entered at a timing different from that when the communication interval is equal, and there is an effect of shifting the sleep cycle and the traffic generation timing. Further, it is desirable that at least one of the plurality of values of the sleep transition threshold value i _{th be} a value larger than an assumed communication interval. When sleep transition threshold i _th is not less than the communication distance, the effect of shifting the generation timing of the sleep period and traffic in sleep at different times and equal to the communication distance.

In particular, if the value is twice or more the communication interval, traffic with delay due to sleep and traffic without delay with sleep occur. Furthermore, if the value is a value that is twice or more the communication interval and a value other than the vicinity of an integral multiple of the communication interval, the effect of shifting the timing is great. That is, the value of _{i min} 0 near the variation range of the sleep transition threshold _{i th (i} max _{~i min)} is, other than the vicinity of integral multiples of the maximum value _{i max} communication distance times the value and the communication distance envisaged Is desirable.

  In the above description, the sleep time Ts and the sleep transition threshold is are shown as independent values, but the sleep time Ts and the sleep transition threshold it may always be the same value.

  In the present embodiment, by changing the sleep time Ts and the sleep transition threshold value it, it is possible to prevent synchronization between the sleep and the arrival timing of data, and to add flexibility to the sleep with respect to the communication interval.

(Embodiment 4)
In the present embodiment, the OLT 91 changes at least one of the sleep time Ts and the sleep shift threshold value i _th and instructs the ONU 92. FIG. 8 shows a configuration example of the optical communication system according to the present embodiment.

  The optical communication system according to the present embodiment is an optical communication system using a PON in which an OLT 91 and an ONU 92 are connected by an optical transmission line, and the OLT 91 includes a switching unit 11, an observation unit 12, and a sleep instruction unit 13. The switching unit 11, the observation unit 12, and the sleep instruction unit 13 include a central processing unit (CPU) provided in the OLT 91, a field programmable gate array (FPGA), and a ASIC (Ligration using an integrated circuit for integration of an Application Specialized Integrated Circuit). Can be performed.

The switching unit 11 changes at least one of the sleep time Ts and the sleep transition threshold value i _th . The change in at least one of the sleep time Ts and the sleep shift threshold value i _th is as described in the first to third embodiments.
The observation unit 12 determines whether or not the ONU 92 may be put into the sleep state using the sleep transition threshold value i _th . At this time, when the switching unit 11 changes the sleep shift threshold value i _th , the observation unit 12 uses the sleep shift threshold value i _th changed by the switch unit 11.
When the observation unit 12 determines that the sleep state may be set, the sleep instruction unit 13 transmits a sleep instruction to the ONU 92. At this time, when the switching unit 11 changes the sleep time Ts, the sleep instruction unit 13 transmits the changed sleep time Ts of the switching unit 11 to the ONU 92.

The determination as to whether the ONU 92 may be put into the sleep state in the observation unit 12 may be performed, for example, by observing at least one of the communication interval, the bandwidth used, and the queue length, and comparing the observation result with the sleep transition threshold i _th. , It is determined that the ONU 92 may be put into the sleep state. It is preferable that the sleep transition threshold value i _th varied in the switching unit 11 be varied for each observation target in the observation unit 12.

When the observation unit 12 observes the communication interval, when the transmission interval of the frame transmitted to the ONU 92 or the reception interval of the frame received from the ONU 92 or both of them exceeds the sleep transition threshold i _th for a predetermined time, It is determined that the ONU 92 may be put into the sleep state. At this time, the determination may be made based on whether or not the average value of the communication intervals has exceeded the sleep transition threshold value i _th .

When the observation unit 12 observes the used band, when the used band of the flow transmitted to the ONU 92 or the used band of the flow received from the ONU 92 falls below the sleep transition threshold i _th for a predetermined time, It is determined that the ONU 92 may be put into the sleep state. At this time, the determination may be made based on whether or not the average value of the used band has exceeded the sleep transition threshold value i _th .

When the observation unit 12 observes the queue length, the queue length of the queue for temporarily storing the frame transmitted to the ONU 92 and / or the queue length of the queue for temporarily storing the frame received from the ONU 92 are determined in advance. It is determined that the ONU 92 may be put to the sleep state when the value falls below the sleep transition threshold value i _th for a given time. At this time, the determination may be made based on whether or not the average value of the queue length has exceeded the sleep transition threshold value i _th .

  When receiving the sleep instruction, the ONU 92 shifts to the sleep state. At this time, the ONU 92 uses the sleep time Ts notified from the OLT 91 as the sleep time Ts shown in FIG.

Optical communication system according to this embodiment, since having the above configuration, it is possible to vary at least one of the sleep time Ts and the sleep transition threshold i _th of ONU92.

In the present embodiment, the example in which the sleep instruction unit 13 notifies the ONU 92 of the sleep time Ts of the OLT 91 after the ONU 92 transmits the sleep request to the OLT 91, but the invention according to the present embodiment is not limited thereto. . For example, the notification may be made from the observation unit 12. For example, before the ONU 92 transmits the sleep request to the OLT 91, the OLT 91 may notify the ONU 92 of the sleep time Ts in advance. For example, the OLT 91 may periodically notify the ONU 92 of the sleep time Ts changed by the switching unit 11, may notify the ONU 92 in response to the change, and may issue a sleep instruction, a sleep request, or a PLOAM (Physical Layer). The communication may be performed at the time of communication such as an Operations And Maintenance (OMN) cell or an OMCI (ONU Management and Control Interface). When changing the sleep transition threshold of the opponent ONU 92, it is desirable to transmit the sleep transition threshold i _th to the opponent ONU 92.

(Embodiment 5)
In the present embodiment, ONU92 is varied at least one of the sleep time Ts and the sleep transition threshold i _th. FIG. 9 shows a configuration example of the optical communication system according to the present embodiment.

  In the optical communication system according to the present embodiment, in an optical communication system using a PON in which an OLT 91 and an ONU 92 are connected by an optical transmission line, the ONU 92 includes a switching unit 21, an observation unit 22, and a sleep instruction unit 23. The switching unit 21, the observation unit 22, and the sleep instruction unit 23 can be executed by using a CPU provided in the ONU 92.

The switching unit 21 changes at least one of the sleep time Ts and the sleep transition threshold value i _th . The change in at least one of the sleep time Ts and the sleep shift threshold value i _th is as described in the first to third embodiments.
The observation unit 22 determines whether or not the ONU 92 may be put into the sleep state using the sleep transition threshold value i _th . At this time, when the switching unit 21 changes the sleep shift threshold value i _th , the observation unit 22 uses the sleep shift threshold value i _th changed by the switch unit 21.
When the observation unit 22 determines that the sleep state may be set, the sleep instruction unit 23 sets the ONU 92 to the sleep state. At this time, when the switching unit 21 changes the sleep time Ts, the sleep instruction unit 23 uses the sleep time Ts changed by the switching unit 21.

The determination as to whether the ONU 92 may be put into the sleep state in the observation unit 22 may be performed by, for example, observing at least one of the communication interval, the used band, and the queue length, as in the observation unit 12 of the fourth embodiment. It is determined that the ONU 92 may be put into the sleep state based on a result of comparison between the result and the sleep transition threshold value i _th . It is preferable that the sleep transition threshold value i _th varied in the switching unit 21 is varied for each observation target in the observation unit 22.

When the observation unit 22 observes the communication interval, when the transmission interval of the frame transmitted to the OLT 91 or the reception interval of the frame received from the OLT 91 or both of them exceeds the sleep transition threshold value i _th for a predetermined time, It is determined that the ONU 92 may be put into the sleep state. At this time, the determination may be made based on whether or not the average value of the communication intervals has exceeded the sleep transition threshold value i _th .

When the observation unit 22 observes the used band, when the used band of the flow transmitted to the OLT 91 or the used band of the flow received from the OLT 91 falls below the sleep transition threshold i _th for a predetermined time, It is determined that the ONU 92 may be put into the sleep state. At this time, the determination may be made based on whether or not the average value of the used band has exceeded the sleep transition threshold value i _th .

When the observation unit 22 observes the queue length, the queue length of the queue for temporarily storing the frame transmitted to the OLT 91 and / or the queue length of the queue for temporarily storing the frame received from the OLT 91 are determined in advance. It is determined that the ONU 92 may be put to the sleep state when the value falls below the sleep transition threshold value i _th for a given time. At this time, the determination may be made based on whether or not the average value of the queue length has exceeded the sleep transition threshold value i _th .

Optical communication system according to this embodiment, since having the above configuration, it is possible to vary at least one of the sleep time Ts and the sleep transition threshold i _th of ONU92.

In the present embodiment, an example is described in which the ONU 92 independently varies the sleep transition threshold value i _th and the sleep time Ts, but the invention according to the present embodiment is not limited to this. For example, when the observation unit 22 determines that the sleep state may be set, the sleep instructing unit 23 may transmit a sleep request to the OLT 91, may notify the OLT 91 of a change, and may issue a sleep instruction or a sleep request. Communication may be performed during communication of a PLOAM cell, OMCI, or the like. When changing the sleep transition threshold value i _th of the opposing OLT 91, it is desirable to transmit the sleep transition threshold value i _th to the opposing OLT 91.

(Embodiment 6)
In the present embodiment, both the ONU 92 and the OLT 91 change at least one of the sleep time Ts and the sleep transition threshold value i _th . FIG. 10 shows a configuration example of the optical communication system according to the present embodiment.

  In the optical communication system according to the present embodiment, in an optical communication system using a PON in which the OLT 91 and the ONU 92 are connected by an optical transmission line, the OLT 91 includes the switching unit 11, the observation unit 12, and the sleep instruction unit 13, and the ONU 92 performs the switching. A unit 21, an observation unit 22, and a sleep instruction unit 23 are provided. The functions and operations of the switching unit 11, the observation unit 12, the sleep instruction unit 13, the switching unit 21, the observation unit 22, and the sleep instruction unit 23 are as described in the fourth and fifth embodiments.

In the present embodiment, both the ONU 92 and the OLT 91 change at least one of the sleep time Ts and the sleep transition threshold value i _th . Therefore, ONU92 and OLT91, it is preferable to perform the synchronization of sleep time Ts and the sleep transition threshold _{i th.}

Optical communication system according to this embodiment, since having the above configuration, it is possible to vary at least one of the sleep time Ts and the sleep transition threshold i _th of ONU92. When the ONU 92 and the OLT 91 are not switched in synchronization, it is desirable that at least the sleep time Ts be shared between the ONU 92 and the OLT 91. The notification of the sleep time Ts may be performed at any time after switching, such as a periodic notification, a sleep instruction, a sleep request, or a communication of a PLOAM cell or OMCI.

(Embodiment 7)
In the present embodiment, a configuration other than the OLT 91 and the ONU 92 changes at least one of the sleep time Ts and the sleep shift threshold i _th . FIG. 11 shows a configuration example of the optical communication system according to the present embodiment.

  In the optical communication system according to the present embodiment, a sleep control device 94 is connected upstream of the OLT 91. The sleep control device 94 includes a switching unit 41, an observation unit 42, and a sleep instruction unit 43. The switching unit 41, the observation unit 42, and the sleep instruction unit 43 can be executed using a CPU provided in the sleep control device 94.

The switching unit 41 changes at least one of the sleep time Ts and the sleep transition threshold value i _th . The change in at least one of the sleep time Ts and the sleep shift threshold value i _th is as described in the first to third embodiments.
The observation unit 42 determines whether or not the ONU 92 may be put into the sleep state using the sleep transition threshold value i _th . At this time, when the switching unit 41 varies the sleep transition threshold value i _th , the observation unit 42 uses the sleep transition threshold value i _th varied by the switching unit 41.
When the observation unit 42 determines that the sleep state may be set, the sleep instruction unit 43 transmits a sleep instruction to the ONU 92. At this time, when the switching unit 41 changes the sleep time Ts, the sleep instruction unit 43 transmits the sleep time Ts changed by the switching unit 41 to the OLT 91 and the ONU 92.

The determination as to whether the ONU 92 may be put into the sleep state in the observation unit 42 may be performed, for example, by observing at least one of a communication interval, a used band, and a queue length, and comparing the observation result with the sleep transition threshold i _th. , It is determined that the ONU 92 may be put into the sleep state. It is preferable that the sleep transition threshold value i _th varied in the switching unit 41 be varied for each observation target in the observation unit 42.

When the observation unit 42 observes the communication interval, the ONU 92 may be put into the sleep state when the transmission interval of the frame transmitted by the OLT 91 or the ONU 92 or both of them exceeds the sleep transition threshold value i _th for a predetermined time. Is determined. At this time, the determination may be made based on whether or not the average value of the communication intervals has exceeded the sleep transition threshold value i _th .

When the observation unit 12 observes the used band, when the used band allocated to the ONU 92 falls below the sleep transition threshold value i _th for a predetermined time, it is determined that the ONU 92 may be put into the sleep state. At this time, the determination may be made based on whether or not the average value of the used band has exceeded the sleep transition threshold value i _th .

When the observing unit 12 observes the queue length, the OLT 91 temporarily stores a frame to be transmitted to the ONU 92 in a queue, and the frame received from the ONU 92 temporarily stores a queue in the OLT 91 to the OLT 91. At least one of the queue length of the queue for temporarily storing the frame to be stored in the ONU 92 and the queue length of the queue for temporarily storing the frame received from the OLT 91 in the ONU 92 has fallen below the sleep transition threshold value i _th for a predetermined time. Then, it is determined that the ONU 92 may be put into the sleep state. At this time, the determination may be made based on whether or not the average value of the queue length has exceeded the sleep transition threshold value i _th .

  When receiving the sleep instruction, the ONU 92 shifts to the sleep state. At this time, the ONU 92 uses the sleep time Ts notified from the sleep control device 94 as the sleep time Ts shown in FIG.

Optical communication system according to this embodiment, since having the above configuration, it is possible to vary at least one of the sleep time Ts and the sleep transition threshold i _th of ONU92.

  Note that, in the present embodiment, an example in which the sleep control device 94 is connected to the OLT 91 has been described, but the invention according to the present embodiment is not limited to this. For example, the sleep control device 94 may be connected upstream of the OLT 91, may be provided in a device that transmits data downstream of the ONU 92, or may be provided in a device that controls the OLT.

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

11, 21, 41: switching units 12, 22, 42: observation units 13, 23, 43: sleep instruction unit 91: OLT
92: ONU
93: delay compensator 94: sleep control device

Claims (8)

An optical communication system using a passive optical network in which an optical line terminal and a subscriber side device are connected via an optical transmission line and data is transmitted and received at a constant communication interval,
A plurality of values are used as the sleep time and the interval is changed in advance so that the sleep time for putting the subscriber device in the sleep state is different from a multiple of the communication interval, and the order in which the values are changed is set in advance. Or generate the value with random numbers,
Optical communication system. An optical communication system using a passive optical network in which an optical line terminal and a subscriber side device are connected via an optical transmission line and data is transmitted and received at a constant communication interval,
The sleep time is varied so that the sleep time for putting the subscriber device in the sleep state is different from a multiple of the communication interval,
As the sleep time is different from a multiple of the communication interval, further changing a sleep transition threshold for transitioning the subscriber device to a sleep state,
The sleep transition threshold uses at least one of the communication interval, the bandwidth used by the subscriber unit, the amount of data transmitted to the subscriber unit, and the amount of data received from the subscriber unit. Determined
Optical communication system. The optical network unit is connected to the optical line and the optical network unit, the optical network unit using a passive optical network for transmitting and receiving data at a constant communication interval, the optical network unit,
A plurality of values are used as the sleep time and the interval is changed in advance so that the sleep time for putting the subscriber device in the sleep state is different from a multiple of the communication interval, and the order in which the values are changed is set in advance. A switching unit that changes or generates the value by using a random number ,
A sleep instructing unit that instructs the sleep time to the subscriber device;
A station device comprising: The switching unit, the sleep time is different from a multiple of the communication interval, further change the sleep transition threshold to transition the subscriber device to the sleep state,
The sleep instructing unit instructs the sleep transition threshold to the subscriber device,
The sleep transition threshold uses at least one of the communication interval, the bandwidth used by the subscriber unit, the amount of data transmitted to the subscriber unit, and the amount of data received from the subscriber unit. Determined
The station apparatus according to claim 3. Using the sleep transition threshold, further comprising an observation unit to determine whether the subscriber unit may be in a sleep state,
The sleep instructing unit, when the observation unit determines that the subscriber unit may be in the sleep state, notifies the subscriber unit of a sleep instruction instructing to transition to a sleep state,
The station apparatus according to claim 4. The optical network unit is connected to an optical line and the optical network unit, the optical network unit using a passive optical network for transmitting and receiving data at a fixed communication interval, the optical network unit,
The sleep time, in which at least some of the circuits included in the device itself are put into the sleep state, is changed from a multiple of the communication interval by using a plurality of values as the sleep time. A switching unit that is set in advance or is changed by generating the value with a random number;
A sleep instruction unit that puts the circuit into a sleep state;
A subscriber device comprising: The optical network unit is connected to an optical line and the optical network unit, the optical network unit using a passive optical network for transmitting and receiving data at a fixed communication interval, the optical network unit,
A switching unit that varies the sleep time, so that a sleep time for putting at least a part of the circuit provided in the sleep state is different from a multiple of the communication interval,
A sleep instruction unit that puts the circuit into a sleep state;
With
The switching unit further varies a sleep transition threshold for transitioning to a sleep state so that the sleep time is different from a multiple of the communication interval,
The sleep transition threshold uses at least one of the communication interval, the bandwidth used by the subscriber device, the amount of data transmitted to the subscriber device, and the amount of data received from the subscriber device. Determined
Subscriber equipment. Using the sleep transition threshold, further comprising an observation unit to determine whether the subscriber unit or the circuit may be put into a sleep state,
The sleep instructing unit sets the circuit to a sleep state when the observation unit determines that the subscriber unit or the circuit may be set to a sleep state,
The subscriber device according to claim 7.

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