JP5847002B2 - Communication system, subscriber side device, station side device, and power saving control method - Google Patents

Description

  The present invention relates to a communication system, a subscriber side device, a station side device, and a power saving control method.

  As a digital signal transmission method for transmitting data using a communication cable, for example, there is an Ethernet (registered trademark) technology defined in IEEE (The Institute of Electrical and Electronics Engineers) -802.3. Among them, for example, when the transmission medium is an optical fiber, there is GE-PON (Gigabit Ethernet (registered trademark) -Passive Optical Network) defined by IEEE-802.3-2008 (see Non-Patent Document 1 below). ).

  On the other hand, in recent years, power saving techniques for reducing power consumption in communication apparatuses have been studied. For example, when communication is performed between the communication device a and the communication device b, the communication device a and the communication device b, or one of the communication device a and the communication device b is the device when there is no signal transmission / reception. Power consumption is reduced by stopping unused internal functions.

  One of the power-saving methods is to check the connectivity between communication devices after switching to the power-saving state when there is no signal transmission / reception, and to exchange information for returning from the power-saving state when a new communication occurs. In order to do this, there is a method of periodically canceling the power saving state.

  The operation of the method for periodically canceling the power saving state will be described. A power saving instruction including an operation state time T1 and a power saving state time T2 is transmitted from the communication device b to the communication device a. In the communication apparatus “a”, after the processing delay time has elapsed, the operation state and the power saving state are alternately repeated at a cycle specified by T1 and T2. In the time zone T1, transmission waiting data is exchanged between the communication device a and the communication device b.

  Another example of the power saving method will be described. The communication device c notifies the communication device a of information relating to the presence / absence of transmission waiting data. When the communication device a receives information indicating that there is no transmission waiting data, the communication device a shifts to a power saving state after the delay time has elapsed. The communication device c repeats the transmission of the presence / absence of transmission waiting data at the determined time interval T3. The connectivity is confirmed between the communication device a and the communication device c every time interval T3.

  These power saving methods are premised on exchanging the presence / absence of transmission-waiting data and promptly shifting to an operating state when there is transmission-waiting data.

  Patent Document 1 discloses a technique for calculating a power saving time that can be set based on a link state and a buffer amount and optimizing the power saving time.

  Patent Document 2 discloses a technique for periodically or regularly monitoring the presence or absence of a specific frame such as VoIP (Voice over Internet Protocol) and shifting to a power saving state when there is no specific frame.

JP 2011-259057 A JP 2012-4642 A

IEEE Std 802.3 (TM) -2008 IEEE Standard for Information technology-Telecommunications and information exchange between systems-Local and metropolitan area networks-Specific requirements Part3: Carrier sense multiple access with Collision Detection (CSMA / CD) Access Method and Physical Layer Specifications

  However, if a conventional technique is used, a power saving effect exceeding a certain level can be expected, but a function for monitoring or processing transmission-waiting data is activated at all times or regularly. For this reason, there has been a problem that there is a restriction on the length of time to enter the power saving state. In addition, when there is data waiting to be transmitted, it is necessary to promptly shift to an operating state, and thus there is a problem that in an actual operation, the time for shifting to a power saving state is extremely short, and a power saving effect cannot be expected.

  The present invention has been made in view of the above, and an object of the present invention is to obtain a communication system, a subscriber-side device, a station-side device, and a power-saving control method that can efficiently save power.

In order to solve the above-described problems and achieve the object, the present invention is a communication system including a subscriber-side device and a station-side device, wherein the subscriber-side device and the station-side device are in a power saving mode. The subscriber side device alternately repeats the power saving state and the operating state for a predetermined time in the power saving mode in a cycle configured by the duration of the power saving state and the duration of the operating state. A subscriber-side power saving control unit that transmits phase information, which is information indicating an initial phase at the time of starting or a phase in the cycle at the current time, to the station-side device, and the station-side device receives the received A phase control unit for controlling the start timing of the power saving state of the own device so that the time when the own device is in the power saving state based on the phase information coincides with the time when the subscriber side device is in the power saving state; Place Under the control of the control unit and the power saving state and the station-side power saving control unit that controls so as to repeat the operation state alternately, characterized in that it comprises a.

  According to the present invention, there is an effect that power saving can be achieved efficiently.

FIG. 1 is a diagram illustrating a configuration example of a communication system according to the first embodiment. FIG. 2 is a chart showing an example of a conventional power saving control method. FIG. 3 is a chart showing another example of a conventional power saving control method. FIG. 4 is a diagram illustrating a configuration example of the subscriber side device according to the first embodiment. FIG. 5 is a diagram illustrating a configuration example of the station side device according to the first embodiment. FIG. 6 is a diagram illustrating a configuration example of a communication terminal. FIG. 7 is a chart showing an example of communication between the subscriber side device and the station side device during normal operation. FIG. 8 is a chart showing an example of the phase-synchronized power saving operation of the first embodiment. FIG. 9 is a chart illustrating an example of the phase-synchronized power saving operation according to the second embodiment. FIG. 10 is a chart illustrating an example of the phase-synchronized power saving operation according to the third embodiment. FIG. 11 is a diagram illustrating a configuration example of the subscriber side device according to the fourth embodiment. FIG. 12 is a diagram illustrating a configuration example of the station side device according to the fourth embodiment. FIG. 13 is a chart illustrating an example of the phase-synchronized power saving operation according to the fourth embodiment.

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

Embodiment 1 FIG.
FIG. 1 is a diagram showing a configuration example of a first embodiment of a communication system according to the present invention. As shown in FIG. 1, the communication system of the present embodiment includes a subscriber side device 10, a station side device 20, a communication terminal 30, and a communication terminal 40.

  The subscriber side device 10 and the station side device 20 are connected by a transmission medium 1 such as an optical fiber cable or an optical coupler. In addition, although the example provided with one subscriber side apparatus 10 is given here, there may be a plurality of subscriber side apparatuses 10 connected to the station side apparatus 20. The communication terminal 30 is, for example, an HGW (Home Gate Way) device, a VoIP (Voice over Internet Protocol) device, a PC (Personal Computer), or the like, and is connected to the subscriber side device 10 via the transmission medium 2. The communication terminal 40 is an L2SW (Layer 2 Switch) or the like, and is connected to the station side device 20 by the transmission medium 3. One or more communication terminals 30 may be connected to the subscriber side device 10. The transmission media 2 and 3 may be any media, but are LAN (Local Area Network) cables, for example. The station-side device 20 is connected to the upper network via the communication terminal 40.

  Here, a GE-PON system will be described as an example of a communication system to which the power saving control method according to the present invention is applied, but the transmission medium and the transmission method are not limited to this example.

  Hereinafter, the direction from the station-side device 20 to the subscriber-side device 10 is referred to as a downlink direction, and the direction from the subscriber-side device 10 to the station-side device 20 is referred to as an uplink direction.

  Here, a conventional power saving control method will be described. FIG. 2 is a chart showing an example of a conventional power saving control method. The example of FIG. 2 is a method of periodically canceling the power saving state. A power saving instruction including the operating state time T1 and the power saving state time T2 is transmitted from the communication device b to the communication device a (step S1). In the communication apparatus “a”, after the processing delay time has elapsed, the operation state and the power saving state are alternately repeated at a cycle specified by T1 and T2. In the time zone T1, transmission waiting data is exchanged between the communication device a and the communication device b. Specifically, the communication device b transmits an inquiry as to whether there is data waiting to be transmitted (step S2). When there is transmission data, the communication device a notifies the communication device b that there is data as a response to the inquiry (step S2). The communication device b that has received this response notifies the communication device a to output data (step S4), and the communication device a transmits a response to this notification (notification of outputting data) (step S5). Thereafter, the communication device a transmits transmission data (step S6).

  FIG. 3 is a chart showing another example of a conventional power saving control method. In the example of FIG. 3, the communication device c notifies the communication device a of information regarding the presence / absence of transmission-waiting data (steps S11, S12, S18). When the communication device a receives information indicating that there is no transmission waiting data (step S12), the communication device a shifts to the power saving state after the delay time has elapsed. In the communication device c, even when there is no transmission data, transmission of presence / absence of transmission waiting data is repeated at a predetermined time interval T3. The connectivity is confirmed between the communication device a and the communication device c every time interval T3. The communication device a and the communication device b are inquired about transmission waiting data as in FIG. 2 (step S13). If there is transmission data from the communication device c, the communication device a has transmission waiting data. (Step S14), and Steps S15 to S17 similar to Steps S4 to S6 in FIG.

  In the conventional power saving control method described with reference to FIGS. 2 and 3, the function of monitoring or processing transmission waiting data is periodically activated. For this reason, the time for continuing the power saving state is limited, and it is difficult to perform efficient power saving. In the present embodiment, the power saving state can be continued even when uplink / downstream data is generated by the operation described below, and efficient power saving can be performed.

  Next, the operation of the present embodiment will be described. The subscriber-side device 10 and the station-side device 20 alternately execute and stop communication at a preset time when there is no uplink / downlink traffic. That is, a preset sleep time (a time for stopping communication by setting the transmission / reception function as a power saving state) and an active time (a time for returning from the power saving state and executing communication) are alternately repeated. Further, the subscriber side device 10 performs a power saving operation (repetition of execution and stop of communication) in the time requested by the station side device 20, and the station side device 20 adjusts the phase with the subscriber side device 10. However, there is a case where the power saving operation is performed in a synchronized state. This phase is a phase with respect to a repetition period composed of one sleep time and active time. If limited to the GE-PON system, time division multiplex communication is performed for uplink communication and broadcast communication is performed for downlink communication. In that case, the subscriber side apparatus 10 and the station side apparatus 20 synchronize time with each other.

  FIG. 4 is a diagram illustrating a configuration example of the subscriber side apparatus 10 according to the present embodiment. As shown in FIG. 4, the subscriber-side device 10 of the present embodiment includes a host device communication unit 11, a power saving control unit 12 (subscriber side power saving control unit), a memory 13, and a lower device communication unit. 14.

  The host device communication unit 11 performs data transmission / reception processing with the station side device 20. The host device communication unit 11 supplies the data received from the station side device 20 to the memory 13 and the power saving control unit 12. The memory 13 holds the supplied data, and the data held in the memory 13 is read by the lower-level device communication unit 14 and transmitted to the communication terminal 30.

  For uplink data, the lower-level device communication unit 14 receives data from the communication terminal 30 (first communication terminal, lower-level communication terminal) and transmits the data from the higher-level device communication unit 11 to the station-side device 20 via the memory 13. Is done. The data of the power saving control unit 12 is transmitted to the communication terminal 30 and the station-side device 20 via the lower-level device communication unit 14 and the higher-level device communication unit 11, respectively.

  The host device communication unit 11 includes a PON control unit 16, an optical transmission unit 17, and an optical reception unit 18. The PON control unit 16 supplies the data received from the power saving control unit 12 or the memory 13 to the optical transmission unit 17. The PON control unit 16 distributes the data received by the optical receiving unit 18 to the power saving control unit 12 and the memory 13 according to the data type. The optical transmission unit 17 converts the data received from the PON control unit 16 into an optical signal and outputs the optical signal to the transmission medium 1. The optical receiver 18 converts the optical signal received via the transmission medium 1 into an electrical signal, and supplies the converted electrical signal to the PON controller 16.

  The power saving control unit 12 controls the start and stop of functions inside the apparatus. In addition, the host device communication unit 11 and the lower device communication unit 14 are notified of time information (referred to as phase information) with respect to the repetition period of the start and stop of communication that are executed alternately. The memory unit 13 temporarily stores the supplied data.

  The lower level device communication unit 14 includes a UNI (User Network Interface) control unit 141 and a PHY circuit (UNI PHY circuit) 142. The UNI control unit 141 performs UNI control with the communication terminal 30, and the PHY circuit 142 performs physical layer processing with the communication terminal 30. The UNI control unit 141 supplies data received from the power saving control unit 12 or the memory 13 to the communication terminal 30 via the PHY circuit 142.

  FIG. 5 is a diagram illustrating a configuration example of the station-side device 20 according to the present embodiment. As shown in FIG. 5, the station side device 20 of the present embodiment includes a host device communication unit 21, a power saving control unit 22 (station side power saving control unit), a memory 23, a lower communication device 24, A phase adjustment unit 25.

  The host device communication unit 21 performs data transmission / reception processing with the communication terminal 40 (second communication terminal, host communication terminal). The host device communication unit 21 supplies the data received from the communication terminal 40 to the memory 23. The memory 23 holds the supplied data, and the data held in the memory 23 is read by the lower-level device communication unit 24 and transmitted to the subscriber-side device 10.

  For upstream data, the lower-level device communication unit 24 receives data from the subscriber-side device 10 and supplies it to the memory 23 and the phase adjustment unit 25. The data supplied to the memory 23 is transmitted from the higher-level device communication unit 21 to the communication terminal 40. Further, phase information is notified from the phase adjustment unit 25 to the power saving control unit 22. The power saving control data generated by the power saving control unit 22 is transmitted to the subscriber side device 10 and the communication terminal 40 via the lower device communication unit 24 and the upper device communication unit 21, respectively.

  The lower apparatus communication unit 24 includes a PON control unit 26, an optical transmission unit 27, and an optical reception unit 28. The PON control unit 26 supplies the data received from the power saving control unit 22 or the memory 23 to the optical transmission unit 27. Further, the data received by the optical receiver 28 is distributed to the phase adjuster 25 and the memory 23 according to the data type.

  The optical transmission unit 27 converts the data from the PON control unit 26 into an optical signal and outputs the optical signal to the transmission medium 1. The optical receiver 28 converts the optical signal received via the transmission medium 1 into an electrical signal, and supplies the converted electrical signal to the PON controller 26.

  The phase adjustment unit 25 extracts the phase information from the received data, and adjusts the start and stop of the function inside the apparatus that is being executed by the power saving control unit 22 so as to be in phase with the phase information.

  The power saving control unit 22 controls the start and stop of functions inside the apparatus. Further, the power saving control unit 22 notifies the higher-level device communication unit 21 and the lower-level device communication unit 24 of phase information with respect to the repetition period of the start and stop of communication executed alternately. The memory unit 23 temporarily stores the supplied data.

  The host device communication unit 21 includes an NNI (Network Node Interface) control unit 211 and a PHY circuit (NNI PHY circuit) 212. The NNI control unit 211 performs NNI control with the communication terminal 40, and the PHY circuit 212 performs physical layer processing with the communication terminal 40. Further, the NNI control unit 211 supplies the data received from the power saving control unit 22 or the memory 23 to the communication terminal 40 via the PHY circuit 212.

  FIG. 6 is a diagram illustrating a configuration example of the communication terminals 30 and 40. Although the configurations of the communication terminal 30 and the communication terminal 40 may be different, it is assumed here that the configurations of the communication terminal 30 and the communication terminal 40 are the same.

  Here, first, the communication terminal 30 will be described. The communication terminal 30 includes a memory 31 and a device communication unit 33. The memory 31 temporarily stores the supplied data. The device communication unit 34 includes a PHY control unit 32 and a PHY circuit 34. The PHY control unit 32 supplies the data received from the memory 31 to the transmission medium 2 via the PHY circuit 34 and adjusts the data output timing.

  The configuration of the communication terminal 40 includes the above-described memory 31, device communication unit 33, PHY control unit 32, PHY circuit 34, and transmission medium 2 as the memory 41, device communication unit 43, PHY control unit 42, PHY circuit 44, and transmission medium. Except for changing to 3, it is the same as the communication terminal 30.

  Next, normal operation in the communication system of the present embodiment will be described. In normal operation, the subscriber-side device 10 and the station-side device 20 synchronize time with each other, perform time division multiplex communication for uplink communication, and broadcast for downlink communication.

  The station-side device 20 allocates a time during which uplink communication is possible to each subscriber-side device 10 so that data transmitted by the subscriber-side device 10 does not collide within the transmission medium 1 during uplink communication. The subscriber side device 10 transmits data at the time assigned by the station side device 20 in the uplink communication. In this way, time division multiplex communication is performed in the uplink direction.

  Thus, during normal operation, the station-side device 20 performs broadcast transmission to the subscriber-side device 10, and the subscriber-side device 10 communicates with the station-side device 20 according to the time assigned to its own device. Time-division multiplex communication. The station-side device 20 allocates a time during which communication can be performed periodically so that the subscriber-side device 10 can request data transmission, and performs a call to notify the time when communication is possible. The subscriber side device 10 that has received this call responds to the allocated communicable time regardless of the presence or absence of data to be transmitted. Further, the station-side device 20 considers that there is an abnormality when there is no response for a predetermined time or more from the subscriber-side device 10 to which a communicable time is assigned. During normal operation, such a periodic call is continued even after instructing the subscriber side device 10 to shift to the power saving mode (power saving instruction).

  FIG. 7 is a chart showing an example of communication between the subscriber side device 10 and the station side device 20 during normal operation. When the station apparatus 20 determines that the subscriber apparatus 10 is to be shifted to the power saving mode, the station apparatus 20 instructs the subscriber apparatus 10 to shift to the power saving mode (power saving instruction) (step S21). The condition for determining that the subscriber-side device 10 is to be shifted to the power saving mode is, for example, that the data to be transmitted to the subscriber-side device 10 is less than or equal to a certain amount during a certain time and transmitted from the subscriber-side device 10. When there is no data to be transmitted, the data to be transmitted to the subscriber side device 10 is not more than a certain amount during a certain time, and when the subscriber side device 10 is requested to shift to the power saving mode, There are no restrictions on this condition. Note that the power saving instruction stores a time T1 during which the operation state is entered and a time T2 during which the power saving state is entered.

  When receiving the power saving instruction, the subscriber side device 10 returns a response to the instruction (step S22), and shifts to the power saving mode. In the power saving mode, the time T2 for entering the power saving state and the time T1 for entering the operation state are alternately repeated.

  The station-side device 20 periodically transmits a call (step S23). While the subscriber side device 10 is in the power saving state (period T2), the response from the subscriber side device 10 is not returned, and the response from the subscriber side device 10 is returned at the time T1 when the subscriber side device 10 is in the operating state. (Step S24). When ending the power saving mode of the subscriber side device 10, the station side device 20 transmits a request to end the power saving mode (power saving end request) a plurality of times at regular intervals (step S25). The subscriber side device 10 does not return a response to the power saving end request in the period T2, but returns a response to the power saving end request in the period T1 (step S26), and ends the power saving mode.

  Next, the phase-synchronized power saving operation of this embodiment will be described. In the conventional power saving operation, when a plurality of subscriber-side devices 10 are connected, if any one of the subscriber-side devices 10 is transmitted, the station-side device 20 is in a communicable state. There must be. For this reason, the station side apparatus 20 can stop communication only for the time when all the subscriber side apparatuses 10 will be in a power saving state. Further, when uplink data is generated in the subscriber side device 10 and downlink data is generated in the station side device 20, the data is stored in the memory 13 and the memory 23, respectively, and is in a power saving (sleep) state. However, it is necessary to quickly start the function inside the apparatus (active state).

  FIG. 8 is a chart showing an example of the phase-synchronized power saving operation of the present embodiment. According to the phase-synchronized power saving operation of the present embodiment shown in FIG. 8, even when uplink / downlink data is generated, it is possible to continue the power saving state. Further, since the memory can be stopped while in the power saving state, more effective power saving can be expected.

  As shown in FIG. 8, the power saving control unit 22 of the station side device 20 refers to the memory 23 and saves depending on whether or not the amount of data transmitted to the subscriber device 10 falls below a certain amount during a certain time. It is determined whether or not to perform power operation (step S101). If the data amount exceeds a certain amount during a certain time, it is determined that the power saving operation is not performed (No in step S101), and the determination in step S101 is repeated. On the other hand, when the amount of data to be transmitted to the subscriber device 10 falls below a certain amount in a certain time, it is determined to execute the power saving operation (Yes in step S101). In this case, the power saving control unit 22 designates a sleep time (corresponding to the above-described T1) and an active time (corresponding to the above-described T2), and saves power to the subscriber side device 10 via the lower-level device communication unit 24. A request to shift to the mode is made (step S102). However, when the sleep time and the active time are set in advance, the operations up to here can be omitted.

  In the subscriber side device 10, the power saving control unit 12 stores the sleep time and active time received from the station side device 20, or preset sleep time and active time. The power saving control unit 12 transmits the stored sleep time, active time, and phase information to the communication terminal 30 and the station side device 20 via the lower device communication unit 14 and the upper device communication unit 11 (step S201).

  The power saving control unit 12 starts the operation in the power saving mode based on the stored sleep time and active time and the initial phase information (step S202). Here, the sleep target functions are the PON control unit 16, the optical transmission unit 17, the optical reception unit 18, the UNI control unit 141, the PHY circuit 142, and the memory 13. Note that some of these may be set as sleep targets without sleeping.

  The phase information is information representing the phase at that time when the period composed of one set of sleep time and active time is 1 period and 1 period is 2π, and the initial phase information is the power saving mode The phase (that is, initial value) at the start of operation is shown. Any value can be used as the initial phase information. For example, the power saving control unit 12 may hold a preset value. For example, when the sleep time is T2, the active time is T1, and the sleep time and the active time are alternately repeated, the start position of the sleep time is set to phase 0. Therefore, the phase when (T2 + T1) / 2 has elapsed after the start of the sleep time T1 is π, and the phase when (T2 + T1) has elapsed is 2π (= 0).

  Since this phase information is used to synchronize the sleep time, the phase value and time need to be associated with each other. Therefore, in step S201, for example, when initial phase information is transmitted as phase information together with the start time of the power saving mode in step S202, or when the transmission in step S201 and the start of the power saving mode in step S202 are almost simultaneous. Since the transmission time of step S201 can be handled as the start time of the power saving mode, only the initial phase information may be transmitted. Note that step S201 may be performed after step S202. In this case, not the initial phase information but the phase information indicating the phase at that time is transmitted in step S201. The initial phase information notification method is not limited.

  Here, the start time of the sleep time is indicated by using the phase information. However, the present invention is not limited to this, and any information may be used as long as the information can be used to know the start time of the periodic sleep time. . For example, the start time of the first sleep time may be notified.

  The station side device 20 transfers the information transmitted in step S201 to the phase adjustment unit 25 via the lower level device communication unit 24 (step S103). The phase adjustment unit 25 controls the power saving control unit 22 based on the transferred information (step S104). Specifically, the phase adjustment unit 25 is in phase with the subscriber side device 10 based on the sleep time, the active time and the phase information received from the subscriber side device 10 (the sleep time and the active time match, The power saving control unit 22 is controlled so as to implement the power saving mode (the start time of the sleep time coincides).

  Thereafter, the station-side device 20 transmits the sleep time and active time controlled by the own device and the phase information to the subscriber-side device 10 and the communication terminal 40 via the lower-level device communication unit 24 and the higher-level device communication unit 21. (Step S105). When the subscriber device 10 is already in the power saving state, transmission to the subscriber device 10 can be omitted.

  Based on the control from the phase adjustment unit 25, the station side device 20 starts the power saving operation in the same phase as the subscriber side device 10 by the power saving control unit 22 (step S106). Here, the sleep target functions are the PON control unit 26, the optical transmission unit 27, the optical reception unit 28, the NNI control unit 211, the PHY circuit unit 212, and the memory 23. Note that some of these may be set as sleep targets without sleeping. When a plurality of subscriber-side devices 10 are connected, the phase adjustment unit 25 controls the station-side device 20 to be in a sleep state during a time period in which all the subscriber-side devices 10 are in a sleep state.

  Through steps S201 and S105, the communication terminal 30 and the communication terminal 40 grasp the timings of the sleep state and the active state of the subscriber side device 10 and the station side device 20, respectively. The communication terminal 30 and the communication terminal 40 determine whether the subscriber side device 10 and the station side device 20 are in a sleep state, respectively, when uplink data and downlink data are generated (steps S301 and S401). If it is determined by this determination that the device is in the sleep state, the data is stored in the memory 31 and the memory 41, respectively. In the example of FIG. 8, at the time of step S301 and step S401, the subscriber side device 10 and the station side device 20 are in a sleep state. Thereafter, the communication terminal 30 and the communication terminal 40 wait until the subscriber side device 10 and the station side device 20 are in the active state, respectively, and then read and transmit the stored data (steps S302 and S402). As described above, the phase information transmitted in steps S201 and S105 is information indicating the timing when the subscriber-side device 10 and the station-side device 20 are in the power saving state. This is information indicating the time to wait for transmission.

  Further, when the communication terminal 30 and the communication terminal 40 determine that the subscriber-side device 10 and the station-side device 20 are in an active state when uplink data and downlink data are generated, the communication terminal 30 starts data transmission as they are. (Steps S303 and S403).

  In addition, the communication terminal 30 and the communication terminal 40 store a certain amount of data in the memory 31 and the memory 41, respectively, and when it is necessary to immediately transmit the data, the power saving control unit 12 and the station of the subscriber apparatus 10 are required. A data transmission request is transmitted to the power saving control unit 22 of the side device 20 (steps S304 and S404). The power saving control unit 12 and the power saving control unit 22 that have received the data transmission request shift to the active state and end the power saving mode (steps S203 and S107). In addition, when applying the process of immediately transitioning to the active state when a data transmission request is received, the subscriber-side device 10 uses part of the UNI control unit 141 and the PHY circuit 142, and the station-side device 20 performs NNI control. The part 211 and a part of the PHY circuit 212 must always be in an active state.

  In the example of FIG. 8, the subscriber-side device 10 and the station-side device 20 are in the active state almost simultaneously by steps S203 and S107, but either one of the communication terminal 30 and the communication terminal 40 is When the data transmission request is not transmitted, the subscriber side device 10 and the station side device 20 that do not receive the data transmission request may continue the sleep state.

  After the above processing, the communication terminal 30 and the communication terminal 40 transmit uplink data and downlink data, and return to the state of step S101. When the station side device 20 shifts to the active state by the data transmission request and the subscriber side device 10 continues in the sleep state, for example, the station side device 20 stores the downlink data received from the communication terminal 40 in the memory. 23, and the stored data is transmitted at the timing when the subscriber-side device 10 becomes active. When the subscriber side device 10 shifts to the active state by the data transmission request and the station side device 20 continues in the sleep state, for example, the subscriber side device 10 stores the uplink data received from the communication terminal 30 in the memory 13. And a transmission time allocation request for data transmission is transmitted at a timing when the station side device 20 becomes active. Upon receiving the transmission time assignment request, the station side device 20 ends the power saving mode and performs transmission time assignment to the subscriber side device 10.

  Note that it may be possible to select between the power saving operation of the normal operation described in FIG. 7 and the phase synchronous power saving operation described in FIG. As the power saving operation, only the phase-synchronized power saving operation described in FIG. 8 may be performed.

  As described above, in the present embodiment, the subscriber-side device 10 notifies the communication terminal 30 and the station-side device 20 of phase information that is information indicating the timing of the sleep time and the active time, and the station-side device 20 Based on the received phase information, the user's own sleep time is set so as to match the subscriber device 10 as much as possible. Further, the station-side device 20 notifies the communication terminal 40 of phase information that is information indicating the timing of the sleep time and the active time of the own device, and the communication terminal 30 and the communication terminal 40 can generate data to be transmitted, When the subscriber-side device 10 and the station-side device 20 to which they are connected are in the sleep state, the data is stored without being transmitted, and is transmitted after the subscriber-side device 10 and the station-side device 20 are in the active state. did. For this reason, the sleep time of the subscriber side apparatus 10 and the station side apparatus 20 can be ensured long, and a power saving can be achieved efficiently.

Embodiment 2. FIG.
FIG. 9 is a chart showing an example of the phase-synchronized power saving operation of the communication system according to the second embodiment of the present invention. The configuration of the communication system of the present embodiment is the same as that of the first embodiment. Hereinafter, a different part from Embodiment 1 is demonstrated.

  Step S101 to step S105, step S201, and step S202 are the same as those in the first embodiment. In the present embodiment, the subscriber side device 10 transmits a Pause frame defined in IEEE 802.3 immediately before the start of the sleep time after shifting to the power saving mode (step S204).

  The Pause frame is a frame for waiting for transmission from the other party, and a time for waiting for transmission can be set. In the Pause frame transmitted in step S204, the Pause frame is received by setting a waiting time so that transmission is waited for only the sleep time (or a value obtained by adding a value considering a certain delay time to the sleep time). The communication terminal 30 stores data without performing data transmission while the subscriber-side device 10 is in the sleep state.

  Similarly, the station apparatus 20 transmits a Pause frame immediately before the start of the sleep time after shifting to the power saving mode (step S108). Accordingly, the communication terminal 40 that has received the Pause frame accumulates data without performing data transmission while the station-side device 20 is in the sleep state. The operations of the present embodiment other than those described above are the same as those of the first embodiment.

  In addition, when transmitting a Pause frame in this way, transmission to the communication terminal 30 and the communication terminal 40 may not be performed in steps S201 and S105. In FIG. 9, the subscriber side device 10 transmits the Pause frame to the station side device 20, but the Pause frame may not be transmitted to the station side device 20. Similarly, although the station side device 20 transmits the Pause frame to the subscriber side device 10 as well, the station side device 20 may not transmit the Pause frame.

  As described above, in the present embodiment, the subscriber-side device 10 and the station-side device 20 send a Pause frame for instructing transmission waiting for the sleep time to the communication terminal 30 and the communication terminal 40 immediately before the start of the sleep time. Each was sent. For this reason, the same effect as Embodiment 1 can be acquired using a Pause frame.

Embodiment 3 FIG.
FIG. 10 is a chart showing an example of the phase-synchronized power saving operation of the communication system according to the third embodiment of the present invention. The configuration of the communication system of the present embodiment is the same as that of the first embodiment. Hereinafter, a different part from Embodiment 1 is demonstrated.

  Step S101 to step S105, step S201, and step S202 are the same as those in the first embodiment. In the present embodiment, the subscriber side device 10 transmits a Pause frame defined in IEEE 802.3 immediately before the start of the sleep time after shifting to the power saving mode (step S204a). Similarly, after shifting to the power saving mode, the station-side device 20 transmits a Pause frame immediately before the start of the sleep time (step S108a). In the present embodiment, these Pause frames are set to wait for transmission for an infinite time. In this case, the subscriber-side device 10 and the station-side device 20 need to notify the communication terminal 30 and the communication terminal 40 that their own devices are in an active state, and therefore wait for 0 hours (no need to wait for transmission). ) Is transmitted (steps S205 and S109).

  In FIG. 10, a Pause frame waiting for 0 hours is transmitted within the sleep time. In this case, only the function for transmitting the Pause frame is shifted to the active state before the sleep time ends. Alternatively, a Pause frame waiting for 0 hour may be transmitted immediately after entering the active state after the sleep time.

  As described above, in the present embodiment, the subscriber-side device 10 and the station-side device 20 send a Pause frame that instructs transmission standby for an infinite time immediately before the start of the sleep time to the communication terminal 30 and the communication terminal 40, respectively. The Pause frame is transmitted to the communication terminal 30 and the communication terminal 40 to notify the waiting for 0 hour at the end of the sleep time. For this reason, the same effect as Embodiment 1 can be acquired using a Pause frame.

Embodiment 4 FIG.
FIG. 11: is a figure which shows the structural example of the subscriber side apparatus 10a of Embodiment 4 of the communication system concerning this invention. FIG. 12 is a diagram illustrating a configuration example of the station-side device 20a according to the present embodiment. The configuration of the communication system of the present embodiment is the same as that of the first embodiment except that the subscriber side device 10 and the station side device 20 are replaced with the subscriber side device 10a and the station side device 20a, respectively. Components having the same functions as those in the first embodiment are denoted by the same reference numerals as those in the first embodiment, and redundant description is omitted.

  As shown in FIG. 11, the subscriber side device 10 a of the present embodiment includes a power saving control unit 12 a and a memory 13 a instead of the power saving control unit 12 and the memory 13 of the first embodiment. As shown in FIG. 12, the station side device 20a of the present embodiment includes a power saving control unit 22a and a memory 23a instead of the power saving control unit 22 and the memory 23 of the first embodiment.

  In the present embodiment, the timing of data transmitted from communication terminal 30 and communication terminal 40 is adjusted according to the priority of data. In the present embodiment, the memories 13a and 23a have a plurality of storage areas corresponding to the priorities, and can be stored in the corresponding areas of the memories 13a and 23a for each priority.

  FIG. 13 is a chart showing an example of the phase-synchronized power saving operation of the present embodiment. Step S101 to step S105, step S201, and step S202 are the same as those in the first embodiment. In the present embodiment, when data to be transmitted is generated, the communication terminals 30 and 40 determine whether the subscriber side device 10a and the station side device 20a are in the sleep state as in the first embodiment (step S301, 401). If it is determined in this determination that the terminal is in the sleep state, the communication terminals 30 and 40 store the data other than the high priority data in the memory 31 and the memory 41, respectively, and start transmission of data in the case of the high priority data. (Steps S305 and 405). In the case of data other than high priority, transmission is started when the subscriber-side device 10a and the station-side device 20a are in the active state, similarly to steps S302 and S402 described in the first embodiment. In addition, there is a method of referring to the priority bit in the data for the priority identification, but there is no restriction on the priority identification method.

  The subscriber side device 10a and the station side device 20a that have received the high priority data from the communication terminals 30 and 40 may immediately transfer the data to the station side device 20a and the subscriber side device 10a, respectively. After waiting until this, high priority data may be transmitted to the station side device 20a and the subscriber side device 10a, respectively. When transmitting high priority data to the station side device 20a and the subscriber side device 10a immediately (without waiting for the active state), the station side device 20a and the subscriber side device 10a are in the power saving state. Among the PON control unit, the optical transmission unit, and the optical reception unit, necessary minimum functions (minimum, the PHY circuits 212 and 142, the NNI control unit 211, and the UNI control unit 141) are set in an operating state. Even when the high priority data is transmitted immediately, the low priority memory area can be kept in the sleep state.

  When the data to be transmitted is generated, if the subscriber side device 10a and the station side device 20a are in the active state as in the first embodiment, the high priority data and the other than the high priority are the same as in the first embodiment. Is transmitted as it is to the subscriber side apparatus 10a and the station side apparatus 20a (steps S303 and S403). Steps S304, S203, S404, and S107 are the same as those in the first embodiment.

  In the present embodiment, it is necessary for the subscriber-side device 10a and the station-side device 20a to receive high-priority data from the communication terminal 30 and the communication terminal 40 even in the sleep state. For this reason, at least the UNI control unit 141 and the PHY circuit 142 need to be in the active state even in the sleep state in the subscriber side apparatus 10a, and at least the NNI in the station side apparatus 20a even in the sleep state. The control unit 211 and the PHY circuit 212 need to be in an active state. However, this is not necessary if a function for detecting data reception is provided even in the sleep state.

  In the subscriber side device 10a and the station side device 20a, when high priority data is received in the sleep state, the power saving control unit 12a and the power saving control unit 22a correspond to the high priority of the memory 13a and the memory 23a. The area can be made active, and the low priority areas of the memory 13a and the memory 23a can remain in the sleep state.

  Further, as described in the second and third embodiments, a Pause frame may be used to wait for transmission of data other than high priority.

  As described above, in the present embodiment, the communication terminals 30 and 40 do not wait for the high-priority data to enter the active state even when the subscriber-side device 10a and the station-side device 20a are in the sleep state. Was sent to. As a result, power saving can be measured efficiently as in the first embodiment, and transmission delay of high priority data can be reduced. In addition, in the subscriber-side device 10a and the station-side device 20a, when high-priority data is received in the sleep state, the low-priority area of the memory 23a remains in the sleep state, thereby further reducing power consumption. Can do.

  As described above, the communication system, the subscriber side device, the station side device, and the power saving control method according to the present invention are useful for a communication system that achieves power saving, and are particularly suitable for a PON system.

1, 2, 3 Transmission medium 10, 10a Subscriber side device 11, 21 Host device communication unit 12, 12a, 22, 22a Power saving control unit 13, 13a, 23, 23a, 31, 42 Memory 14, 24 Lower device communication Units 16, 26 PON control unit 17, 27 Optical transmission unit 18, 28 Optical reception unit 20, 20a Station side device 25 Phase adjustment unit 30, 40 Communication terminal 32, 42 PHY control unit 33, 43 Device communication unit 141 UNI control unit 142, 212, 34, 44 PHY circuit 211 NNI control unit

Claims (11)

A communication system comprising a subscriber side device and a station side device,
The subscriber side device and the station side device are:
In the power saving mode, the power saving state and the operating state are alternately repeated for a predetermined time,
The subscriber side device is:
Phase information that is information indicating an initial phase at the time of starting a power saving mode in a cycle constituted by a duration of a power saving state and a duration of an operation state or a phase in the cycle at the present time Power-saving control unit on the subscriber side,
With
The station side device
A phase control unit that controls the start timing of the power saving state of the own device so that the time when the own device enters the power saving state matches the time when the subscriber side device enters the power saving state based on the received phase information When,
A station-side power-saving control unit that performs control to alternately repeat the power-saving state and the operating state based on the control by the phase control unit;
A communication system comprising: A first communication terminal connected to the subscriber side device;
A second communication terminal connected to the station side device;
With
The subscriber side device is:
Upon receiving uplink data from the first communication terminal, the uplink data is transferred to the station side device,
The subscriber-side power saving control unit transmits the time when the own device is in a power saving state to the first communication terminal as a transmission standby time by a Pause frame ,
The station side device
When downlink data is received from the second communication terminal, the downlink data is transferred to the subscriber side device,
The station-side power saving control unit transmits a time when the own apparatus is in a power saving state to the second communication terminal as a transmission standby time by a Pause frame ,
When the first communication terminal determines that the uplink data to be transmitted is within the transmission standby time based on the received transmission standby time, the first communication terminal accumulates the uplink data until the transmission standby time ends. And waiting for transmission, and after the transmission standby time has ended, transmit the stored uplink data to the subscriber side device,
When the second communication terminal determines that the downlink data to be transmitted is within the transmission standby time based on the received transmission standby time, the second communication terminal accumulates the downlink data until the transmission standby time ends. 2. The communication system according to claim 1, wherein the communication device waits for transmission and transmits the accumulated downlink data to the station side device after the transmission standby time ends. The subscriber side device notifies the first communication terminal of the transmission standby time by transmitting the phase information of the own device to the first communication terminal,
The said station side apparatus notifies the said transmission waiting time to the said 2nd communication terminal by transmitting the said phase information of an own apparatus to the said 2nd communication terminal, The said 2nd communication terminal is characterized by the above-mentioned. Communication system. The subscriber side device transmits the Pause frame designating the duration time of the power saving state as the transmission waiting time to the first communication terminal before starting the power saving state, thereby setting the transmission waiting time to the first communication terminal. 1 to the communication terminal,
The station side device transmits the Pause frame designating the duration of the power saving state as the transmission waiting time to the second communication terminal before starting the power saving state, thereby setting the transmission waiting time to the second communication terminal. The communication system according to claim 2, wherein the communication terminal is notified. The subscriber side device transmits a Pause frame designating a maximum time as a transmission standby time to the first communication terminal before starting the power saving state, and 0 hours as a transmission standby time at the end of the power saving state. Is transmitted to the first communication terminal to notify the transmission waiting time to the first communication terminal,
The station side device transmits a Pause frame designating a maximum time as a transmission standby time to the first communication terminal before the start of the power saving state, and sets 0 hours as a transmission standby time at the end of the power saving state. The communication system according to claim 2, wherein the transmission standby time is notified to the second communication terminal by transmitting a designated Pause frame to the second communication terminal. When the first communication terminal determines that it is within the transmission standby time when uplink data to be transmitted is generated, the first communication terminal transmits uplink data with high priority to the subscriber side apparatus and uplink data other than high priority. Is stored without transmitting, and after the subscriber side device is in an operating state, the stored upstream data other than high priority is transmitted to the subscriber side device,
When the second communication terminal determines that it is within the transmission waiting time when downlink data to be transmitted is generated, the second communication terminal transmits downlink data with high priority to the station side device and downlink data other than high priority. 6. The data is stored without transmitting, and the stored downstream data other than high priority is transmitted to the station side device after the station side device is in an operating state. The communication system according to one. A station-side device connected to a subscriber-side device that alternately repeats a power-saving state and an operating state for each predetermined time in the power-saving mode,
In the power saving mode, the power saving state and the operating state are alternately repeated for a predetermined time,
The station side device
From the subscriber side device , an initial phase when starting a power saving mode in a cycle constituted by a duration of a power saving state and a duration of an operation state in the subscriber side device or a phase in the cycle at the present time The time when the device is in the power saving state based on the received phase information matches the time when the subscriber side device is in the power saving state. A phase control unit for controlling the start timing of the power state;
A station-side power-saving control unit that performs control to alternately repeat the power-saving state and the operating state based on the control by the phase control unit;
A station-side device comprising: The said station side power saving control part transmits the information which shows the time when an own apparatus will be in a power saving state to a high-order communication terminal to which an own apparatus connects as a transmission waiting time by a Pause frame. Station side equipment. A subscriber-side device connected to a station-side device that alternately repeats a power-saving state and an operating state for each predetermined time in the power-saving mode,
In the power saving mode, the power saving state and the operating state are alternately repeated for a predetermined time,
Phase information that is information indicating an initial phase at the time of starting a power saving mode in a cycle constituted by a duration of a power saving state and a duration of an operation state or a phase in the cycle at the present time Power-saving control unit on the subscriber side,
A subscriber-side device comprising: The subscriber- side power saving control unit transmits information indicating a time when the own device is in a power saving state to a lower communication terminal to which the own device is connected as a transmission standby time by a Pause frame. The subscriber side device as described. A power saving control method in a communication system comprising a subscriber side device and a station side device,
A power saving step in which the subscriber side device and the station side device alternately repeat a power saving state and an operating state for each predetermined time in a power saving mode;
It is information indicating the initial phase at the time when the subscriber-side device starts the power saving mode in the period constituted by the duration of the power saving state and the duration of the operating state or the phase in the current period. Subscriber-side power saving control step of transmitting phase information to the station-side device;
The start timing of the power saving state of the local apparatus so that the time when the local apparatus enters the power saving state matches the time when the subscriber side apparatus enters the power saving state based on the received phase information. A phase control step for controlling
A station-side power saving control step for controlling the station-side device to alternately repeat a power saving state and an operating state based on the control of the phase control step;
A power saving control method comprising:

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