JP2015033139A - Power saving method using synchronized sleep cycle in optical subscriber network - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for power saving of an optical network termination device and an optical line termination device.SOLUTION: A first sleep group 500 has a sleep cycle of T sleep_1, a second sleep group 510 has a sleep cycle of T sleep_2, and a third sleep group 520 has a sleep cycle of T sleep_3. An ONT 550 is included in the first sleep group, an ONT 551 and an ONT 553 are included in the second sleep group and an ONT 552 is included in the third sleep group, respectively. A data frame 530 includes a sleep synchronism message SA. The ONT 551 receives the sleep synchronism message in a sleep aware state, immediately shifts to an asleep state, then operates a timer for T sleep_2 and shifts to the sleep aware state after the timer expires. Upon receipt of a low power state end request message, the ONT 551 shifts to an active held state, ends a synchronized sleep mode and operates as a normal mode.

Description

  Provided is a power saving method for an optical network termination (ONT) and an optical line termination (OLT). More specifically, the present invention provides a power saving method in an optical network termination device and an optical line termination device using a synchronized sleep period.

  Recently, ITU-T has been actively researching power management methods for optical network termination devices, recognizing the importance of power saving in next-generation optical subscriber networks. As a power management method for an optical network termination device, a doze sleep mode and a cyclic sleep mode are known.

  In the doze sleep mode, only the optical transmitter is periodically turned on / off while the optical receiver of the optical network termination device is always on. The doze sleep mode has the advantage of stable operation although the efficiency of power saving is small.

  On the other hand, the cyclic sleep mode is a method of periodically turning on / off all of the optical transmission unit and the optical reception unit of the optical network termination device. The cyclic sleep mode has an advantage of improving the efficiency of power saving, but requires a more complicated control method to realize an accurate operation.

  According to one aspect, the optical network termination device receives a sleep synchronization message for the first sleep group from the optical line termination device, and when the optical network termination device is included in the first sleep group, And a power saving method for an optical network termination device including a step of transitioning to an off-sleep state.

  The method may further include a step of transitioning to a sleep aware state in which the optical transmitter is turned on after the first sleep cycle of the first sleep group has elapsed.

  The asleep state may further turn off the optical receiver, and the sleep aware state may further turn on the optical receiver.

  According to an embodiment, when the optical network termination device is not included in the first sleep group, the method may further include a step of maintaining a sleep aware state in which the optical transmitter is turned on.

  The optical network termination devices may be grouped so as to be included in one sleep group among at least one sleep group by signaling with the optical line termination device.

  In addition, the sleep cycle of each of the at least one sleep group may be set differently. Furthermore, the sleep period of each of the at least one sleep group depends on the type of service provided by the optical network termination device included in each of the at least one sleep group and the performance of the hardware of the optical network termination device. May be set differently.

  According to an embodiment, when the optical network termination device receives a low power state termination request message from the optical network termination device, the optical network termination device transitions to an active-held state for normal operation in a sleep-aware state. The method may further include the step of:

  The step of transitioning to the active-held state may transmit a low power state transition end message to the optical line termination device when the optical network termination device transitions to the active-held state.

  According to another embodiment, grouping at least one optical network termination device into at least one sleep group, and transmitting a sleep synchronization message for the at least one sleep group to the at least one optical network termination device. And a power saving method for an optical line termination device.

  According to an embodiment, the grouping step may include the step of setting different sleep periods for the at least one sleep group.

  Further, the step of setting the sleep cycle differently depends on a type of service provided by the optical network termination device included in each of the at least one sleep group and the performance of the hardware of the optical network termination device. The sleep cycle may be set differently.

  In addition, the step of transmitting the sleep synchronization message to the at least one optical network termination device may include transmitting a sleep period corresponding to each of the at least one sleep group to each of the optical network termination devices included in each of the at least one sleep group. A sleep synchronization message may be sent to

  According to an embodiment, when data to be transmitted to the first optical network termination device is received, the optical line termination device transitions from a low power sleep state to an alert sleep state, and the first optical network termination device includes: Removing the first optical network termination device from the included sleep group.

  The step of transitioning to the alert sleep state may further include a step of transmitting a low power state end request message to the first optical network termination device.

  Furthermore, when receiving a low power state change end message from the first optical network termination device, the optical line termination device may further include a step of transitioning from the alert sleep state to an awake force state for normal operation.

  According to an embodiment, the grouping may be performed such that the termination device is included in one sleep group of at least one sleep group by signaling with the optical network termination device.

  According to an embodiment, if there is no traffic to the second optical network termination device during a preset time, transmitting a low power state start request message to the second optical network termination device; and The terminal device may further include a transition from an awake force state for normal operation to a low power sleep state for power saving.

  The step of transitioning to the low power sleep state may include the step of adding the second optical network termination device to a sleep group determined to include the second optical network termination device.

  According to another embodiment, the optical network termination device receives a sleep synchronization message for the first sleep group determined in advance from the optical line termination device, and the optical network termination device is included in the first sleep group. And determining whether to communicate with the optical line termination device according to whether or not communication is performed.

The relationship between a general optical line termination device and an optical network termination device is shown. The operation | movement flow and operation | movement state of the cyclic sleep mode which concern on one comparative example are shown. 1 shows a relationship between an optical line termination device and an optical network termination device according to an embodiment. 2 illustrates an operation flow and an operation state of a power saving method using a synchronized sleep period according to an embodiment. FIG. 6 illustrates an overall sequence of power saving methods using synchronized sleep periods according to one embodiment. FIG. It is a block diagram of the optical network termination device concerning one embodiment. It is a block diagram of the optical line termination device concerning one embodiment. 6 is a flowchart illustrating a power saving method of another optical network termination device according to an embodiment. 3 is a flowchart illustrating a power saving method of an optical line termination device according to an embodiment.

  Hereinafter, some embodiments will be described in detail with reference to the accompanying drawings. However, the scope of rights is not limited or limited by such an embodiment. The same reference numerals provided in each drawing denote the same members.

  The terminology used in the following description has been selected to be general and universal in the related technical field, but other terms may exist depending on the development and / or change of technology, customs, preference of engineers, etc. obtain. Accordingly, the terms used in the following description should not be understood as limiting the technical idea, but should be understood as exemplary terms for describing the embodiments.

  FIG. 1 shows the relationship between a general optical line termination device and an optical network termination device.

  An optical line terminating device (OLT) 110 is a terminating device on the service providing up side as a part of the optical subscriber network. The optical line termination device 110 is a multi-service device that connects the optical subscriber network with other systems. For example, the optical line termination device 110 may connect the optical subscriber network with general cable broadcasting (CATV), IP network, VoIP (Voice over Internet Protocol), or other network networks.

  Optical network terminators (ONTs) 121 to 127 are terminators for connecting to an optical subscriber system constituting the next generation communication network. The optical network terminators 121 to 127 may be connected to the optical line terminator 110 by an optical fiber or the like as an optical terminator on the service subscriber side.

  To explain the power consumption in the network field, the power consumption of the subscriber network accounts for the majority of the total network power consumption. Among them, the ratio of the power consumption of the optical network terminating devices 121 to 127 spread to each home to the total power consumption is large.

  As described above, the importance of power saving in the next generation optical subscriber network is recognized, and there are a doze sleep mode and a cyclic sleep mode as power saving methods discussed as a standard. However, as described above, the doze sleep mode can be operated stably, but the power saving efficiency is low, and the cyclic sleep mode increases the power saving efficiency, but complicated control is required to realize accurate operation. Requires a method.

In addition, the cyclic sleep mode may generate processing delays and deviations that cannot be predicted even though the hardware is complicatedly configured. In order to compensate for the processing delay and deviation, there is a problem that the optical network terminating device has to be set to a larger T- _aware time.

  Hereinafter, the above-described problem will be described in detail by explaining the operation flow and operation state of the cyclic sleep mode.

  FIG. 2 shows an operation flow and an operation state of the cyclic sleep mode according to the comparative example.

  Referring to FIG. 2, the operation flow when the optical network termination device (ONT) according to the comparative example operates in the cyclic sleep mode, the state 210 of the optical network termination device, the state of the optical network termination device 220, and the optical network. The state 240 of the optical transceiver of the termination device is shown.

  The optical network termination device operates as an active hold 211 during a normal operation in which normal data transmission / reception that is not in a power saving state is performed. Here, the normal operation in which normal data transmission / reception is performed is not a state in which the optical receiver or the optical transmitter of the optical network termination device is periodically turned on / off to save power, but the optical receiver continuously. The optical transmitter may be turned on.

  An optical network termination device generates an LSI (Local Sleep Indication) event when there is no traffic for a certain period of time, and a low power state start request message (SA (ON): Sleep Allow (ON)) from the optical network termination device. Wait 231.

  When the first optical network termination device is operating normally on the side of the optical network termination device, it may operate as an awake force 221 state with respect to the first optical network termination device.

  In addition, when there is no traffic to be transmitted to and received from the first optical network terminating device for a certain period of time,! An LWI (! Local Wake-up Indication) event may be generated, and a low power state start request message (SA (ON)) 231 may be immediately transmitted to the first optical network terminating device. Thereafter, the optical line termination device may transition to one Awake Free 222 state in the low power state of the optical line termination device.

  The first optical network terminating device that has received the low power state start request message (SA (ON)) 231 from the optical line terminating device enters one active free 212 state in the low power state of the optical network terminating device. You may make a transition. Further, as a response to the low power state start request message (SA (ON)) 231, a low power state change message (SR (Sleep)) 232 is transmitted to the optical line termination device. Thereafter, the first optical network terminating device starts a cyclic sleep mode in which the states of sleep aware 213, 215 and 217 and the states of sleep 214 and 216 are repeated.

  The optical network unit that has received the low power state change message (SR (sleep)) 232 in the awake free 222 state transitions to the state of the low power sleep (Low Power Sleep) 223. As long as the first optical network terminator maintains the cyclic sleep mode, the optical line terminator maintains the low power sleep 223 state.

The first optical network terminating device turns on the optical transceiver for a period of time during which the state of the sleep aware 213, 215, 217 is maintained during the cyclic sleep mode, in other words, for the T _aware 241 243 hours. On the other hand, the first optical network terminating device turns off the optical transceiver during the time during which the states of the asleeps 214 and 216 are maintained, in other words, during the T- _asleeps 242 and 244 hours.

  The optical line terminator periodically allocates a bandwidth 235 so that it can be received when the first optical network terminator is in the sleep-aware state (Grant) 235. Also, the first optical network terminating device responds to the allocated band (Response) 236 to inform that the first optical network terminating device is operating normally in the cyclic sleep mode.

  If data to be transmitted to the first optical network terminating device is received by the optical line terminating device in the process in which the cyclic sleep mode is continuously performed, an LWI (Local Wake-up Indication) event is generated in the optical line terminating device. Occurs, and the optical line termination device transits to an alert sleep (Alerted Sleep) 224 state.

  Thereafter, the optical line termination device transmits a low power state termination request message SA (OFF) 233 requesting the suspension of the cyclic sleep mode in accordance with the state of the sleep aware 217 of the first optical network termination device.

  The first optical network terminating device that has received the low power state termination request message SA (OFF) 233 transmits a low power state transition termination message SR (Awake) 234 to the optical line termination device to enter the active-held 218 state. Transition. The optical network unit that has received the low power state change end message SR (Awake) 234 transitions to the state of the Awake Force 225 and performs normal operation.

  In the above description, the cyclic sleep mode has been mainly described for the purpose of explanation. However, the doze sleep mode is different from the cyclic sleep mode except that the optical receiver is turned on in the asleep state. It may operate the same. Therefore, the description for the doze sleep mode is omitted.

  In the power saving method using the cyclic sleep mode described above, the cyclic sleep modes of the respective optical network termination devices operate asynchronously with each other. In other words, it means that the on / off operation time of the optical transceiver is different for each optical network terminating device operating in the cyclic sleep mode.

  Therefore, the optical line terminator must accurately grasp the optical transceiver on / off time of the optical network terminator operating in the cyclic sleep mode. Further, the optical line termination device should transmit a message accurately in accordance with the on-time.

  However, such an operation requirement (the optical line termination device transmits a message in accordance with the sleep-aware time of the optical network termination device) has a problem that the optical line termination device requires a very complicated hardware configuration.

As a result, the power saving method using the conventional cyclic sleep mode increases the hardware complexity of the optical line termination device due to asynchronous sleep cycle management between the optical line termination device and the optical network termination device. Cause problems. Moreover, processing delay unpredictable optical line terminator and an optical network unit, causes the compensation problem of _T-aware time must be set sufficiently large _{T-aware (aware)} time and the like jitter and transmission delay.

  FIG. 3 shows the relationship between an optical line termination device and an optical network termination device according to an embodiment.

  In FIG. 3, the optical network termination device 340 according to an embodiment classifies the optical network termination devices 310, 311, 312, 321, 322, 331, 332, 333 into three groups for synchronous sleep cycle management. Show.

  The same sleep synchronization message (SA: Sleep Allow) may be transmitted to all optical network termination devices communicating with the optical line termination device 340. However, it is possible to save power by transmitting sleep synchronization messages (SA) having different periods in consideration of termination of service provided by each optical network termination device and hardware performance of each optical network termination device. It is efficient.

  In FIG. 3, the optical network terminating device 340 groups the optical network terminating devices into the first sleep group 310, the second sleep group 320, and the third sleep group 330. Each sleep group has a different sleep cycle. Here, the sleep cycle may be a time when all the optical transceivers are turned off in the cyclic sleep mode, and may be a time when the optical transmitters are turned off in the doze sleep mode.

  The sleep period of each sleep group may be set differently according to the type of service provided by the optical network termination device included in each sleep group and the performance of the hardware of the optical network termination device.

For example, in the case of an optical network terminating device that provides an Internet telephone (VoIP) service, an event for receiving a telephone call from the optical line terminating device occurs. Therefore, since the sleep cycle of the optical network termination device cannot be set to be long, the optical network termination device that provides the Internet telephone service may be joined to a sleep group having a small sleep cycle T _{sleep (sleep) _i} .

  On the other hand, in the case of an optical network terminating device that provides only simple data service, the sleep cycle may be set longer. Therefore, an optical network terminating device that provides only the simple data service may be joined to a sleep group having a long sleep cycle.

  As a further example, the hardware specifications of the optical transceiver and the electronic circuit used in the optical network termination device may be different. For example, the first optical network termination device may have a hardware specification that can support a short sleep cycle, and the second optical network termination device may have a low hardware specification and cannot support a short sleep cycle. In order to transition from the sleep state to the sleep-aware state, the second optical network termination device requires a longer time than the first optical network termination device. Therefore, it is possible to determine an optical line termination device so as to belong to a sleep group having a suitable sleep cycle in consideration of hardware specifications of the optical network termination device.

The first sleep period T _{sleep _1} first sleep group 310 as described above, the third sleep period T _{sleep _3} second sleep period T _{sleep _2,} and the third sleep group 330 of the second sleep group 320 is different from each other Also good.

  The optical network termination devices may be grouped so as to be included in one sleep group among at least one sleep group by signaling with the optical line termination device 340. The optical line terminator 340 may be grouped so as to be included in a sleep group having a suitable sleep cycle by signaling based on the type of service provided by the optical network terminator and the hardware specifications of the optical network terminator. it can.

  According to one embodiment, the signaling may comprise a process in which an optical line terminator performs an initial bring-up of an optical network terminator. Specifically, the sleep group to which the optical network termination device belongs may be determined in the process of data exchange between the optical network termination device and the optical line termination device by OMCI (ONT Management Control Interface) signaling. In other words, the signaling may be performed in a step in which the optical network terminating device is initially powered on and the optical line terminating device discovers the optical network terminating device and enables a communication service.

  As described above, the sleep group included when the optical network termination device is transitioned to the sleep synchronization state for power saving by signaling with the optical line termination device 340 may be determined. The optical line termination device 340 may manage the members of the sleep group and transmit a sleep synchronization message to the sleep group by a multicast method. Further, the optical line termination device 340 may transmit the sleep synchronization message in the sleep cycle of each sleep group for each sleep group. Therefore, the sleep cycle between optical network terminating devices belonging to the same sleep group can be synchronized.

  In addition, even if it belongs to another sleep group, the sleep period may overlap and the sleep synchronization message may be transmitted simultaneously. Also in this case, the sleep cycle may be synchronized between sleep groups to which the sleep synchronization message is transmitted simultaneously.

  Hereinafter, the power saving method using the synchronized sleep period according to an embodiment will be described in more detail.

  FIG. 4 illustrates an operation flow and an operation state of a power saving method using a synchronized sleep period according to an embodiment.

  Referring to FIG. 4, an optical network termination device state 410, an optical network termination device (ONT) and an optical line termination device (OLT) power saving method using a synchronized sleep period according to an embodiment. The state 420 of the line termination device and the state 440 of the optical transceiver of the optical network termination device are shown.

  The optical network termination device operates in an active hold 411 state during normal operation in which normal data transmission / reception is performed that is not in a power saving state. Here, the normal operation in which normal data transmission / reception is performed is not a state in which the optical receiver or the optical transmitter of the optical network termination device is periodically turned on / off for power saving, but the optical receiver and It may be in a state where the optical transmitter is on.

  The optical network termination device generates an LSI (Local Sleep Indication) event when there is no traffic for a certain period, and the optical network termination device issues a low power state start request message (SA (ON): Sleep Allow (ON)). ) Wait 431.

  On the side of the optical line termination device, when the first optical network termination device operates normally, the first optical network termination device may operate in an awake force 421 state.

  In addition, when there is no traffic to be transmitted / received to / from the first optical network terminating device for a certain period of time,! An LWI (! Local Wake-up Indication) event may be generated and a low power state start request message (SA (ON)) 431 may be immediately transmitted to the first optical network terminating device. The optical line termination device may transmit the low power state start request message (SA (ON)) 431 to the first optical network termination device and then join the first optical network termination device to the sleep group promised in advance by signaling. Good. Thereafter, the optical line termination device may transition to an awake free 422 state.

  The first optical network terminator that has received the low power state start request message (SA (ON)) 431 from the optical line terminator may transition to the active free 412 state. Also, as a response to the low power state start request message (SA (ON)) 431, a low power state change message (SR (Sleep)): 432 is transmitted to the optical line termination device, and the sleep aware 413 You may transition to a state.

  The optical network unit that has received the low power state change message (SR (sleep)) 432 in the awake free 422 state may transition to a low power sleep (423) state. As long as the first optical network terminator maintains a synchronized sleep mode, the optical line terminator can maintain the low power sleep 423 state.

Similarly to the cyclic sleep mode, even if the synchronized sleep mode is used, the time when the state of the sleep aware 413, 415, 417 is maintained, in other words, even if the optical transceiver is turned on during the T _aware 441, 443 hours. Good. On the other hand, the first optical network terminating device may turn off the optical transceiver during the time period during which the states of the _sleep states 414 and 416 are maintained, in other words, during the T sleep_i 442 and 444 hours.

The optical line termination device may periodically transmit a sleep synchronization message (SA (S_i): Sleep Allow (Sleep) _i)) 433 and 434 message to the optical network termination device in a multicast manner. Here, S_i means i-th sleep group, Sleep synchronization message SA (S_i) may be sent with a T _{sleep _i} period. In other words, the optical line termination device may transmit the sleep synchronization message SA (S_i) to the optical network termination device included in each sleep group in the sleep cycle of each sleep group.

When the sleep synchronization message SA (S_i) 433 is received in the sleep aware state 413, the first optical network terminating device transitions to the asleep state 414. The _asleep state 414 of the first optical network terminating device lasts for T _{sleep_i} time. In other words, the duration of the sleep state of the first optical network termination device is the sleep cycle of the sleep group in which the first optical network termination device is included.

The optical network terminating device that was in the _asleep 414 state may transition to the sleep-aware 415 state after T _{sleep_i} time. The optical network terminating device that has transitioned to the sleep-aware 415 state may transition to the asleep 416 state again when receiving the sleep synchronization message SA (S_i) 434 from the optical line terminating device. Further, the optical network terminating device that has been in the _asleep 416 state may transition to the sleep-aware state 417 again after the time of T _{sleep_i} .

  When the data transmitted to the first optical network terminating device is received by the optical line terminating device in the process in which the synchronized sleep mode is continuously performed, an LWI (Local Wake-up Indication) event is generated in the optical line terminating device. Occurs, and the optical network unit transitions to the alert sleep 424 state.

  Thereafter, the optical line termination device transmits a low power state termination request message SA (OFF) 435 requesting the suspension of the cyclic sleep mode in accordance with the state of the sleep aware 417 of the first optical network termination device.

  When the first optical network terminating device receives the low power state termination request message SA (OFF) 435 in the sleep-aware state 417, it transitions to the active-held 418 state for normal operation and performs normal data transmission / reception operation. Also good. Also, the optical line termination device may remove the first optical network termination device from the sleep group including the first optical network termination device.

  At the same time, the first optical network terminating device that has received the low power state termination request message SA (OFF) 435 may transmit a low power state transition termination message SR (Awake) 436 to the optical line termination device. . The optical network unit that has received the low power state change end message SR (Awake) 436 transitions to the state of the awake force 425 and performs normal operation.

  In the above description, the optical transmitter / receiver of the optical network terminating device is turned off together with the cyclic sleep mode for the purpose of explanation. However, the optical receiver is turned on even when only the optical transmitter is turned off together with the doze sleep mode. The remaining operations may be the same except for the state to be performed.

  As described above, the power saving method of the optical network termination device and the optical network termination device according to the embodiment is a low power by signaling with the optical network termination device when the transmission traffic of the optical network termination device does not exist for a certain period of time. The standby power can be minimized by switching to the synchronized mode of the mode.

  In addition, the optical line terminator periodically transmits a sleep synchronization message for each sleep group in a multicast manner, so that the sleep period of the optical network terminator in the synchronized sleep mode of the low power mode is set to the sleep group. Can be synchronized with each other.

Therefore, the power saving method of the optical network termination device and the optical network termination device according to an embodiment can reduce the hardware complexity of the optical network termination device through synchronized sleep cycle management. Further, by solving the T- _aware time compensation problem due to the indispensable delay and minimizing the T- _aware time, the power saving efficiency of the optical network terminating device can be maximized.

  FIG. 5 illustrates an overall sequence of a power saving method using a synchronized sleep period according to an embodiment.

In FIG. 5, three sleep groups are formed, the first sleep group 500 has a sleep cycle of T _{sleep_1} , the second sleep group 510 has a sleep cycle of T _{sleep_2} , and the third sleep group 520 has a T cycle. _It has a sleep cycle of _{sleep_3} .

Although each sleep period is determined freely, T _{sleep _2} To briefly describe the operation is twice the T _{sleep _1,} T _{sleep _3} will be described on the assumption that three times the T _{sleep _1} . The first ONT 550 is included in the first sleep group, the second ONT 551 and the fourth ONT 553 are included in the second sleep group, and the third ONT 552 is included in the third sleep group.

In the data frame 530, SA (S_1), SA (S_2), and SA (S_3) messages may be included and transmitted simultaneously. The first ONT 550 receives the SA (S_1) message in the sleep-aware state and immediately transitions to the _asleep state, and then activates the timer for the T-sleep_1. The second ONT 551 receives the SA (S_2) message in the sleep-aware state and immediately transitions to the _asleep state, and then activates the timer for the T-sleep_2. The third ONT 552 receives the SA (S_3) message in the sleep-aware state and immediately transitions to the _asleep state, and then activates the timer for the T- _{sleep_3} . In the case of the fourth ONT 553, since it is in the current active free state, the received SA (S_2) message has no meaning in the state change.

Since only the SA (S_1) message is transmitted in the data frame 531, only the first ONT 550 included in the first sleep group 500 is meaningful. In the case of the 1ONT550, it may transition gradually sleep aware state ends and the previous T _{sleep _1} timer. After that, if the SA (S_1) message is received, immediately after the transition to the _asleep state, the timer for the T _{sleep_1} is activated again.

  In the case of the second ONT 551 and the third ONT 552, the timer does not end and still operates in the sleep state and the optical transceiver is turned off. In the case of the fourth ONT 553, an SR (sleep) message 537 may be transmitted to the OLT in the active free state to shift to the sleep aware state. In this case, the fourth ONT 553 may receive the SA (S_1) message in the sleep aware state. Since the fourth ONT 553 is included in the second sleep group 510, the SA (S_1) message may be ignored.

  Since the SA (S_1) and SA (S_2) messages are transmitted in the data frame 532, the sleep synchronization function is performed on the ONTs included in the first sleep group 500 and the second sleep group 510. Since the first ONT 550 is included in the first sleep group 500, the first ONT 550 may transition to the asleep state as soon as it receives the SA (S_1) message in the sleep aware state.

In the case of the 2ONT551, because it is in a second sleep group 510, SA (S_2) gradually timer for T _{sleep _2} to receive a message is completed may transition to the sleep-aware state. The second ONT 551 may transition to the _asleep state as soon as the SA (S_2) message is received, and reset the timer for the T sleep_2.

In the case of the third ONT 552, since it is included in the third sleep group 520, it is kept in the sleep state and all the optical transceivers are turned off. Since the fourth ONT 553 is included in the second sleep group 510, if the SA (S_2) message is received in the sleep-aware state, the state may be immediately changed to the _asleep state to set a timer for the T- _{sleep_2} .

  Since SA (S_1) and SA (S_3) messages are transmitted in the data frame 533, the sleep synchronization function is performed for the ONTs included in the first sleep group 500 and the third sleep group 520. Accordingly, the first ONT 550 belonging to the first sleep group 500 and the third ONT 552 belonging to the third sleep group 520 may be synchronized with each other.

  When the LWI request event 560 for the second ONT 551 occurs, the OLT may send an SA (OFF) message to raise the second ONT 551. An SA (OFF) message may be inserted into the data frame 534 and transmitted to the second ONT 551 in a unicast manner.

  Therefore, the data frame 534 may include SA (S_1) and SA (S_2) messages in the multicast method, and SA (OFF) messages in the second ONT 551 in the unicast method.

In the case of the first ONT 550, an exceptional operation state for the SA (S_1) message is shown. The 1ONT550 optical transceiver is turned on as soon as the timer ends for T _{sleep _1,} it must wait in the sleep-aware state. However, the optical transceiver may be turned on late and transition to the sleep-aware state due to a timer error for T- _{sleep_1} or other software or hardware malfunction. In this case, the first ONT 550 may not be able to receive the SA (S_1) message. Thus, the sleep aware state may persist until an SA (S_1) message in data frame 535 is received. The first ONT 550 may transition to the asleep state only after receiving the SA (S_1) message in the data frame 535.

  In the case of the second ONT 552, if an SA (OFF) message is received, the sleep mode may be immediately shifted to the active hold state and the synchronized sleep mode may be terminated to operate as a normal mode.

In the data frame 536, SA (S_1), SA (S_2), and SA (S_3) messages may be included and transmitted simultaneously. The first ONT 550 receives the SA (S_1) message in the sleep-aware state and immediately transitions to the _asleep state, and then activates the timer for the T-sleep_1. The third ONT 552 receives the SA (S_3) message in the sleep-aware state and immediately transitions to the _asleep state, and then activates the timer for the T-sleep_3. The fourth ONT 553 receives the SA (S_2) message in the sleep-aware state and immediately transitions to the _asleep state, and then activates the timer for the T-sleep_2. Since the second ONT 551 is in the active-held state, the received SA (S_2) message has no meaning in the state change.

  FIG. 6 is a block diagram of an optical network termination device according to an embodiment.

  The optical network termination device 600 includes an optical receiver 610, an optical transmitter 620, and a processor 630. The optical receiver 610 may receive data or the like from the optical line terminator 660, and the optical transmitter 620 may transmit data or the like to the optical line terminator 660.

  The optical network termination devices can be grouped so as to be included in one sleep group among at least one sleep group by signaling with the optical line termination device 660. Referring to FIG. 6, the optical network termination devices 600 and 641 are grouped into a first sleep group 640, and the optical network termination devices 651, 652, and 653 are grouped into a second sleep group 650. The grouping method of the optical network termination devices and the like are as described with reference to FIG.

  In order to save power, the optical receiver 610 and the optical transmitter 620 are turned off in the sleep mode and turned on in the sleep aware state in the synchronized sleep mode. Further, as in the doze sleep mode, the optical receiver 610 is always turned on, the optical transmitter 620 is turned off in the asleep state, and turned on in the sleep aware state.

  The processor 630 may control the optical receiver 610 and the optical transmitter 620 to be turned on or off based on the sleep synchronization message received from the optical line termination device 660. The processor 630 is grouped so that the optical network termination device 600 is included in one sleep group among at least one sleep group by signaling with the optical line termination device 660.

  The processor 630 determines whether the received sleep synchronization message is a sleep synchronization message for the first sleep group 640 including the optical network termination device 600. If the received sleep synchronization message is a sleep synchronization message for the first sleep group 640, the processor 630 turns off the optical receiver 610 and the optical transmitter 620.

  On the other hand, if the received sleep synchronization message is not a sleep synchronization message for the first sleep group 640, the processor 630 continues to hold the on state of the optical receiver 610 and the optical transmitter 620.

  Further, the processor 630 may control the state transition of the optical network termination device 600. For example, when a low power state termination request message is received from the optical line termination device 660, the optical network termination device 600 is shifted to an active-held state for normal operation in the sleep-aware state.

  At the same time, when receiving a sleep synchronization message for the first sleep group 640 from the optical line terminator 660, the processor 630 may cause the optical network terminator 600 to transition to an asleep state in which the optical transmitter is turned off.

  FIG. 7 is a block diagram of an optical line termination device according to an embodiment.

  The optical line termination device 700 includes a communication unit 710 and a processor 720. The communication unit 710 may transmit / receive data to / from the optical network termination device.

  The processor 720 may group at least one optical network termination device into at least one sleep group. Further, the processor 720 may set different sleep cycles for at least one sleep group in the process of grouping.

  The sleep cycle of each at least one sleep group may be set differently according to the type of service provided by the optical network termination device included in each sleep group and the performance of the hardware of the optical network termination device. .

  For example, the processor 720 may group the optical network termination devices into the first sleep group 730, the second sleep group 740, and the third sleep group 750 by signaling through the optical network termination device and the communication unit 710. The first sleep group 730 includes optical network termination devices 731 and 732, the second sleep group 740 includes optical network termination devices 741, 742, and 743, and the third sleep group 750 includes an optical network termination device 751. , 752 are included.

  The sleep cycles of the first sleep group 730, the second sleep group 740, and the third sleep group 750 may be set different from each other. The processor 720 uses the communication unit 710 to perform a sleep cycle according to the type of service provided by the optical network termination device included in each sleep group by signaling with each optical network termination device and the hardware performance of the optical network termination device. May be set differently.

  The processor 720 may use the communication unit 710 to transmit a sleep synchronization message to each sleep group in the sleep cycle of each sleep group using a multicast method. The processor 720 may transition the state of the optical network termination device from the sleep-aware state to the asleep state via the sleep synchronization message.

  The processor 720 may transmit a low power state start request message to the specific optical network termination device when there is no traffic in the specific optical network termination device for a certain period of time. The processor 720 may remove the specific optical network termination device from a sleep group including the specific optical network termination device when traffic to be transmitted to the specific optical network termination device is received. At the same time, the processor 720 transmits a low power state termination request message to the specific optical network terminating device, and guides the optical network terminating device to operate in the normal mode.

  Further, the processor 720 may control the state transition of the optical line termination device 700. For example, when data to be transmitted to a specific optical network terminating device is received, the state of the optical line terminating device 700 may be changed from the low power sleep state to the alert sleep state.

  FIG. 8 is a flowchart illustrating a power saving method of another optical network termination device according to an embodiment.

  In step S810, the optical network terminating device receives a sleep synchronization message for the first sleep group from the optical line terminating device. The optical line termination device may transmit a sleep synchronization message in a multicast manner for each sleep group, or may transmit the same sleep synchronization message to the entire optical network termination device.

  In step S820, it is determined whether the optical network termination device is included in the first sleep group. As described above, when the optical network unit transmits a sleep synchronization message in a multicast manner for each sleep group, this step may be omitted and the process may be performed immediately from step S830.

  However, when the optical line terminator transmits the same sleep synchronization message to the entire optical network terminator, it is necessary to precede the process of determining whether the optical network terminator is included in the first sleep group. If the state of the optical network terminating device is changed in response to the sleep synchronization message for all sleep groups, the power saving efficiency may be reduced.

  In step S830, if the optical network termination device is included in the first sleep group, the optical network termination device transitions to an asleep state in which the optical transceiver is turned off. When the optical network termination device is included in the first sleep group, the sleep periods of all the optical network termination devices included in the first sleep group are synchronized via a sleep synchronization message for the first sleep group. When the optical network terminating device transits to the asleep state, the timer for the first sleep cycle is activated.

  In step S840, after the first sleep period of the first sleep group has elapsed, the optical network terminating device transitions to a sleep-aware state in which the optical transceiver is turned on. Even in the synchronized sleep mode for power saving, the optical transceiver needs to be turned on at regular intervals in order to receive a message for operating as the normal mode again.

  If the optical network terminating device is not included in the first sleep group in step S850, the sleep aware state in which the optical transceiver is turned on is maintained. If the state of the optical network termination device is changed in response to the sleep synchronization message for all sleep groups, the efficiency of power saving may be reduced. Therefore, a state change of the optical network termination device does not occur via a sleep synchronization message for another sleep group that is not a sleep group including the optical network termination device.

  FIG. 9 is a flowchart illustrating a power saving method of the optical line termination device according to an embodiment.

  In step S910, the optical line termination device groups the optical network termination device into at least one sleep group by signaling with the optical network termination device. The optical line termination devices may be grouped in consideration of the sleep cycle according to the type of service provided by the optical network termination device and the hardware performance of the optical network termination device.

  In step S920, the optical network unit transmits a sleep synchronization message for at least one sleep group to the optical network unit. The optical line termination device may transmit a sleep synchronization message by a multicast method for each sleep group for each sleep cycle of each sleep group.

  In step S930, when the data to be transmitted to the first optical network terminating device is received, the optical line terminating device transits from the low power sleep state to the alert sleep state. When the optical line termination device transits to the alert sleep state, the low power state termination message may be transmitted to the first optical network termination device.

  In step S940, the optical line termination device removes the first optical network termination device from the sleep group including the first optical network termination device. By removing the first optical network termination device from the sleep group, no further sleep synchronization messages are sent to the first optical network termination device.

  The apparatus described above may be realized by a hardware component, a software component, and / or a combination of a hardware component and a software component. For example, the devices and components described in the embodiments include a processor, a controller, an ALU (arithmetic logic unit), a digital signal processor (digital signal processor), a microcomputer, a FPA (field programmable array), and a PLU (programmable logic). It may be implemented using one or more general purpose or special purpose computers, such as a microprocessor, or a different device capable of executing and responding to instructions. The processing apparatus may execute an operating system (OS) and one or more software applications performed on the operating system. The processing device may also access, store, manipulate, process and generate data in response to software execution. For convenience of understanding, one processing device may be described as being used, but those having ordinary knowledge in the technical field may recognize that the processing device has multiple processing elements and It can be seen that a plurality of types of processing elements are included. For example, the processing device may include multiple processors or one processor and one controller. Other processing configurations are also possible, such as a parallel processor.

  The software may include computer programs, code, instructions, or a combination of one or more of these, may configure the processing device to operate as desired, or may instruct the processing device independently or in combination. . Software and / or data, the machine what type to provide instructions or data to the processing apparatus or is interpreted by the processing device, component, physical devices, virtual devices, computer storage media or device, the signal transmitted Can be embodied permanently or temporarily in the waves. The software may be distributed over computer systems connected to a network and stored or executed in a distributed manner. Software and data may be stored on one or more computer readable recording media.

  The method according to the embodiment may be realized in the form of program instructions capable of executing various processes via various computer means, and recorded on a computer-readable recording medium. The computer readable medium may include one or a combination of program instructions, data files, data structures, and the like. The program instructions recorded on the medium may be specially designed and configured for the purposes of the present invention, and are well known and usable by those skilled in the computer software art. May be. Examples of computer-readable recording media include magnetic media such as hard disks, floppy (registered trademark) disks and magnetic tapes, optical recording media such as CD-ROMs and DVDs, magneto-optical media such as optical disks, and ROMs. A hardware device specially configured to store and execute program instructions, such as RAM, flash memory, etc., may be included. Examples of program instructions include not only machine language codes created by a compiler but also high-level language codes that can be executed by a computer using an interpreter or the like. The hardware device described above may be configured to operate as one or more software modules to perform the operations of the present invention, and vice versa.

  As described above, the present invention has been described with reference to the limited embodiments and drawings. However, the present invention is not limited to the above-described embodiments, and any person having ordinary knowledge in the field to which the present invention belongs can be used. Various modifications and variations are possible from such an embodiment.

  Accordingly, the scope of the present invention is not limited to the disclosed embodiments, but is defined not only by the claims but also by the equivalents of the claims.

Claims (20)

The optical network termination device receiving a sleep synchronization message for the first sleep group from the optical network termination device;
When the optical network termination device is included in the first sleep group, a transition to an asleep state in which an optical transmitter is turned off; and
A power saving method for an optical network termination device.   The method of claim 1, further comprising a transition to a sleep-aware state in which the optical transmitter is turned on after the first sleep period of the first sleep group has elapsed.   3. The method of claim 2, wherein the asleep state further turns off the optical receiver, and the sleep aware state further turns on the optical receiver.   The optical network termination device according to claim 1, further comprising a step of maintaining a sleep aware state in which the optical transmitter is turned on when the optical network termination device is not included in the first sleep group. Power saving method.   2. The optical network termination according to claim 1, wherein the optical network termination devices are grouped so as to be included in one sleep group among at least one sleep group by signaling with the optical line termination device. Device power saving method.   6. The method of claim 5, wherein the sleep periods of the at least one sleep group are set differently.   The sleep period of each of the at least one sleep group depends on the type of service provided by the optical network termination device included in each of the at least one sleep group and the hardware performance of the optical network termination device. The power saving method for an optical network termination device according to claim 6, wherein the power saving method is set differently.   When the optical network termination device receives a low power state termination request message from the optical line termination device, the optical network termination device further includes a step of transitioning to an active-held state for normal operation in a sleep-aware state. The power saving method for an optical network termination device according to claim 1.   9. The step of transitioning to the active-held state transmits a low power state transition end message to the optical line termination device when the optical network termination device transitions to the active-held state. Power saving method for optical network termination equipment. Grouping at least one optical network termination device into at least one sleep group;
Transmitting a sleep synchronization message for the at least one sleep group to the at least one optical network termination device;
A method for reducing the power consumption of an optical line termination device.   The method of claim 10, wherein the grouping includes a step of setting different sleep periods for the at least one sleep group.   The step of setting the sleep cycle differently may be performed according to a type of service provided by an optical network termination device included in each of the at least one sleep group and a hardware performance of the optical network termination device. The method of claim 11, wherein the sleep cycle is set to be different.   The step of transmitting the sleep synchronization message to the at least one optical network termination device is configured to cause the optical network termination device included in each of the at least one sleep group to sleep in a sleep cycle corresponding to each of the at least one sleep group. The method of claim 10, wherein the synchronization message is transmitted. When data to be transmitted to the first optical network terminating device is received, the optical line terminating device transitions from a low power sleep state to an alert sleep state;
Removing the first optical network termination device from a sleep group including the first optical network termination device;
The power saving method for an optical line termination device according to claim 10, further comprising:   The method of claim 14, wherein the transition to the alert sleep state further includes a step of transmitting a low power state termination request message to the first optical network termination device. .   When the low power state change end message is received from the first optical network terminating device, the optical line terminating device further includes a transition from the alert sleep state to an awake force state for normal operation. The power saving method for an optical line termination device according to claim 15.   The grouping step includes grouping so that the optical network termination device is included in one sleep group of at least one sleep group by signaling with the optical network termination device. The power saving method of the optical line termination apparatus of description. If there is no traffic to the second optical network termination device during a preset time, transmitting a low power state start request message to the second optical network termination device;
The optical line termination device transitions from an awake force state for normal operation to a low power sleep state for power saving;
The power saving method for an optical line termination device according to claim 10, further comprising:   19. The step of transitioning to the low power sleep state includes adding the second optical network termination device to a sleep group determined to include the second optical network termination device. A method for reducing the power consumption of the optical line terminator described in 1. The optical network terminating device receiving a sleep synchronization message for the first sleep group determined in advance from the optical line terminating device;
Determining whether to communicate with the optical line termination device according to whether the optical network termination device is included in the first sleep group;
A power saving method for an optical network termination device.

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