JP5882886B2 - User side optical line terminator and power consumption control method for user side optical line terminator - Google Patents

Description

  The present invention relates to a user-side optical line terminator and a power consumption control method for the user-side optical line terminator, and in particular, sleep of a PON interface connected to a station-side optical line terminator (OLT) of a passive optical network (PON). The present invention relates to a user-side optical line terminator having a function and a power consumption control method for the user-side optical line terminator.

  As an optical access system that provides an FTTH (Fiber To The Home) service that directly draws an optical fiber into a general user's home as a transmission path, there is a passive optical network (PON: simply referred to as “PON” hereinafter) system. The PON system includes a station side optical line terminator (OLT: Optical Line Terminal; hereinafter simply referred to as “OLT”) and a plurality of user side optical line terminators (ONU: Optical Network Unit), hereinafter simply referred to as “ONU”. ) Is an optical access network connected by a point-to-multipoint topology through an optical fiber and an optical branching coupler.

  In the PON system, an optical signal transmitted by the OLT as a downlink signal sent from the station side to the user side is branched by an optical branching coupler, and the same downlink signal is transmitted to all ONUs by a broadcast method. Each ONU photoelectrically converts the received optical signal, and the received frame is addressed to itself (including subordinate user equipment) based on a logical link identifier (LLID) included in the received frame. Whether the received frame is selected or not is selected.

  On the other hand, each optical signal transmitted from each ONU as an upstream signal transmitted from the user side to the station side is combined by an optical branching coupler and received by the OLT. At this time, the optical signals transmitted from different ONUs collide (the optical signal from one ONU and the optical signal of another ONU are transmitted through a common optical fiber so that the OLT receives a signal from each ONU. In the PON system, the OLT transmits a GATE signal notifying each ONU of a time and period during which each ONU can transmit, and each ONU receives the received GATE. So-called time division multiple access (TDMA) control is performed in which an optical signal is transmitted to the OLT at a time and a period specified by the signal.

  The downstream signal (OLT to ONU) and the upstream signal (ONU to OLT) are bidirectionally communicated by wavelength multiplexing, that is, using optical signals of different wavelengths.

  Conventionally, various efforts have been made for high speed and low power consumption in the PON system. Among them, as a method for reducing the power consumption of the ONU, “LAN low” that restricts the communication function by temporarily suspending communication with a user side communication device connected via a LAN such as Ethernet (registered trademark). There are “power control” and “PON sleep control” that limits the communication function by temporarily stopping communication between the ONU and the OLT.

  Among these, the LAN low power control is performed by temporarily suspending a part of the function of the LAN interface, which is an ONU interface for the ONU to connect to the user side communication device via the user network such as the LAN. The power consumption is reduced. A protocol standardized by IEEE 802.3 is adopted for a LAN used for connection between a user-side communication device and an ONU. In addition, there is a LAN low power control standardized as IEEE 802.3az in order to save power in an interface circuit for connecting to a LAN.

  On the other hand, the PON sleep control shifts to a “sleep mode” in which at least a part of communication with the OLT is temporarily stopped when communication between the OLT and the ONU is not performed. The sleep mode includes an “uplink sleep mode” that temporarily stops upstream communication from the ONU to the OLT but does not stop downstream communication from the OLT to the ONU, and a “bidirectional sleep” that temporarily stops communication in both directions. Mode ". In any mode, the ONU consumes the PON interface, which is the interface of the ONU that connects to the OLT, by intermittently generating communication between the ONU and the OLT or reducing the communication speed. Electric power can be reduced (for example, Non-Patent Document 1 and Non-Patent Document 2).

  As described above, to reduce the power consumption of the ONU, it is possible to adopt two types of control methods, that is, the LAN low power control for the LAN interface and the PON sleep control for the PON interface.

OKI Technical Review April 2012 / No. 219 Vol. 79 No. 1 IEICE technical report CS2009-2 (2009-04)

  By the way, in the above-described PON sleep control, in order to avoid the adverse effect on the communication application due to the temporary suspension of communication, the transition from the normal mode in which all communication functions with the OLT are operated to the sleep mode is performed by the ONU and the OLT. And when the communication is not performed for a certain period (time Ti), the return from the sleep mode to the normal mode is that the ONU receives a frame to be transmitted to the OLT from the user side communication device, or The OLT receives a frame to be transmitted to the user side communication apparatus via the ONU from the upstream apparatus of the OLT.

  As described above, in the PON sleep control, when communication is not performed during a certain time Ti, the mode is shifted to the sleep mode. Therefore, the time Ti from when the user-side communication apparatus stops communication until the mode shifts to the sleep mode. There has been a problem that the effect of reducing power consumption is reduced due to the above delay and the shortening of the sleep mode period.

  Therefore, an object of the present invention is to shorten the time from when the user-side communication device stops communication until it shifts to the sleep mode, and to improve the ONU power consumption reduction effect by the sleep control of the PON interface.

In order to achieve the above-described object, a user-side optical network unit (ONU) according to the present invention includes, for example, a first interface connected to a user-side communication device via a user network, and a passive optical network (PON). ) Through a second interface connected to a station side optical line termination device (OLT) through the network, the first interface receives a frame from the user side communication device, and the second interface A first transmission / reception unit for transmitting at least a part of a frame received from the station-side optical terminal to the user-side communication device; When the first interface receives a sleep signal indicating a low power transmission / reception state that reduces power consumption related to A first state control unit that limits a function of transmitting or receiving a frame of the first transmission / reception unit and sets the first interface to a low power transmission / reception state that can reduce power consumption of the first interface. The second interface converts an optical signal and an electrical signal to each other, receives a frame from the station-side optical termination device, and receives a frame received from the user-side communication device by the first interface. Triggered by the second transmitting / receiving unit transmitting at least a part to the station side optical line terminating device and the first interface receiving the sleep signal or entering the low power transmitting / receiving state. also transmits the second transmission and reception of the frame by limiting the ability to send and receive, the second interface, the power consumption of the second interface It characterized in that a second state controller to decrease possible sleep.

In addition, a power consumption control method for a user-side optical network unit (ONU) according to the present invention includes a first interface connected to a user-side communication device via a user network and a passive optical network (PON). A second interface connected to a station-side optical line termination device (OLT); and a buffer for holding a frame to be transmitted to the station-side optical termination device (OLT) , wherein the first interface communicates with the user-side communication Transmitting at least a part of the frame received from the apparatus from the second interface to the station-side optical terminal unit, and transmitting at least a part of the frame received from the station-side optical terminal unit by the second interface In the power consumption control method of a user side optical network unit (ONU) that transmits to the user side communication device from one interface, the user The first interface receives a sleep signal indicating that the communication device is in a low power transmission / reception state that limits a function of transmitting or receiving a frame to reduce power consumption related to frame transmission or reception; The first interface that has received the sleep signal restricts the function of transmitting or receiving a frame from the normal transmission / reception state in which the function of transmitting or receiving a frame with the user-side communication device is not restricted, and the first interface The second transmission / reception unit triggered by the step of setting a low power transmission / reception state capable of reducing power consumption of the interface, and when the first interface has received the sleep signal or has entered the low power transmission / reception state The function of transmitting or transmitting / receiving frames is limited, and the second interface is Possess a step of the reduction can sleep power consumption of the second interface, the step of the second interface with the sleep state, the first interface is between the low power transceiver state and The second interface is set in the sleep state after the amount of frames held in the buffer becomes equal to or less than a predetermined value.

Here, in the present invention, the user side optical network unit (ONU) further includes a buffer for holding a frame to be transmitted to the station side optical unit (OLT), and the second state control unit includes: the first interface becomes a pre SL low power transceiver state, and, after the amount of frames that are held in the buffer is equal to or less than a predetermined value, it constitutes the second interface to said sleep state May be.

  In the present invention, the first state control unit further includes a function in which the first interface in the low power transmission / reception state transmits or receives a frame from the low power transmission / reception state by the user side communication device. When receiving an idle signal indicating that a normal transmission / reception state without restriction is received, the first interface transmits / receives a frame to / from the user side communication device from the low power transmission / reception state. The second state control unit is triggered by the fact that the first interface has received the idle signal or has entered the normal transmission / reception state from the low power transmission / reception state. Function for transmitting or transmitting / receiving a frame from / to the sleep state of the second interface by the second transmission / reception unit Usually it may be configured so as to transmit and receive state of not limiting.

  In addition, a user-side optical network unit (ONU) according to the present invention is connected to a user-side communication device via a user network and transmits / receives a frame to / from the user-side communication device. Reduces power consumption by restricting the function to transmit or receive frames, and reducing the power consumption related to frame transmission / reception When receiving a sleep signal indicating that it is in a low power transmission / reception state, it limits the function to transmit or receive frames A first interface that is in a possible low power transmission / reception state, and is connected to a station side optical line terminator through a passive optical network, and converts the optical signal and the electrical signal to each other, A second state in which a frame can be transmitted and received, and a sleep state in which power consumption can be reduced by limiting a function of transmitting or transmitting a frame. And the first interface receives a frame from the user side communication device, and at least a part of the frame received by the second interface from the station side optical terminal device is the user side communication device. The first interface in a low power transmission / reception state capable of reducing power consumption by limiting the function of transmitting or receiving frames, and the user side communication device transmits frames. When receiving an idle signal indicating that a normal transmission / reception state in which a function of transmitting or receiving a frame is not restricted is received from a low-power transmission / reception state in which the function to receive is limited to reduce power consumption related to frame transmission / reception, the first An interface is connected to the user side communication device from the low power transmission / reception state by the first transmission / reception unit. A first state control unit that sets a normal transmission / reception state that does not restrict a function of transmitting or receiving a frame, and the second interface converts an optical signal and an electrical signal to each other, and A second transmission / reception unit for receiving a frame from a device and transmitting at least part of the frame received by the first interface from the user-side communication device to the station-side optical network unit; and the first interface Triggered by the reception of the idle signal or the transition from the low power transmission / reception state to the normal transmission / reception state, the second transmission / reception unit transmits or transmits a frame from the sleep state to the second interface. And a second state control unit configured to perform a normal transmission / reception state without limiting functions.

  According to the present invention, the first interface is notified by the sleep signal that the user-side communication device is in a low power transmission / reception state in which the function of transmitting or receiving frames is limited to reduce power consumption related to frame transmission. Then, the first interface is set to the low power transmission / reception state, and the second interface connected to the passive optical network (PON) is set to the sleep state in response to this. Therefore, after the first interface enters the low power transmission / reception state, there is no need to monitor communication during the time Ti in order to put the second interface into the sleep state, so the second interface is in the sleep state. Can be shortened, and as a result, the effect of reducing the power consumption of the ONU by the sleep control of the second interface can be improved.

FIG. 1 is a diagram showing an outline of a passive optical network system (PON system). FIG. 2 is a diagram conceptually showing the configuration of the user side optical network unit (ONU) according to the embodiment of the present invention. FIG. 3 is a block diagram showing a configuration example of the user side optical network unit (ONU) according to the embodiment of the present invention. FIG. 4 is a sequence diagram illustrating a process in which the PON interface of the user side optical network unit (ONU) according to the embodiment of the present invention shifts from the normal state to the sleep state. FIG. 5 is a sequence diagram illustrating a process in which the PON interface of the user side optical network unit (ONU) according to the embodiment of the present invention returns from the sleep state to the normal state. FIG. 6 is a sequence diagram illustrating a process in which a PON interface of a conventional user-side optical line termination unit (ONU) shifts from a normal state to a sleep state.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[PON system]
FIG. 1 shows a plurality of user-side optical line terminators (hereinafter referred to as “ONUs”) 13-1 to 13 -n (hereinafter, n) included in a passive optical network system (hereinafter referred to as “PON system”) 1. Is an integer.), User communication devices (UT: User Terminal) 14-1 to 14-n are connected via user networks 17-1 to 17-n, respectively.

  Here, as shown in FIG. 1, the PON system 1 includes a station side optical line terminating device (hereinafter referred to as “OLT”) 11 connected to a host device (not shown) constituting a service network, and a plurality of devices. The ONUs 13-1 to 31-n are connected via the optical fibers 15 and 16 and the optical branching coupler 12 in a point-to-multipoint connection form.

In such a PON system 1, the optical signal transmitted from the OLT 11 is branched by the optical branching coupler 12 and received by each of the ONUs 13-1 to 13-n. Each optical signal transmitted from each ONU 13-1 to 13-n is combined by the optical branching coupler 12 and received by the OLT 11.
In the PON system 1, optical signals transmitted from a plurality of different ONUs 13-1 to 13-n collide (an optical signal from one ONU and an optical signal of another ONU are transmitted through a common optical fiber). Therefore, the OLT 11 transmits a GATE signal to each ONU 13-1 to 13-n to prevent the ONT 13-1 to 13-n from receiving a signal from each ONU. n notifies the time and period during which the optical signal can be transmitted. Each ONU 13-1 to 13-n transmits an optical signal to the OLT 11 based on the received GATE signal, thereby performing time division multiple access (TDMA) control.

  On the other hand, the user networks 17-1 to 17-n that connect the respective ONUs 13-1 to 13-n and the user side communication device devices 14-1 to 14-n are connected by signals such as Ethernet (registered trademark), for example. A local area network (LAN: Local Area Network; hereinafter referred to as “LAN”). The user communication devices 17-1 to 17-n may be home gateways to which one or more home communication terminals are connected in addition to the user's personal computer (PC), IP phone terminal, and the like.

[Configuration of ONU]
Next, the ONU according to the present embodiment will be described using the ONU 13-n among the plurality of ONUs 13-1 to 13-n configuring the PON system 1 as an example. Hereinafter, the ONU 13-n may be referred to as “ONU #n”.

  As shown in FIG. 2, the ONU #n sends the ONU #n to the OLT 11 via the optical fiber 16-n, the PON interface unit 131, and the ONU #n to the user communication device 14-n. A LAN interface unit 132, which is an interface for connecting via the LAN 17-n, is provided.

  The PON interface unit 131 receives a frame addressed to ONU #n among the downlink frames transmitted by the OLT 11, performs MAC processing according to the PON interface, and then outputs the frame to the LAN interface unit 132. In addition, the upstream frame output from the LAN interface unit 132 is processed and transmitted along the PON interface.

  On the other hand, the LAN interface unit 132 receives the uplink frame transmitted by the user side communication device 14-n and performs MAC processing or bridge processing according to the LAN interface, and then outputs the MAC frame or bridge processing to the PON interface unit 131. The LAN interface unit 132 performs bridge processing and MAC processing according to the LAN interface on the downlink frame output from the PON interface unit 131, and then transmits the frame to the user side communication device 14-n.

  The user-side communication device 14-n includes a LAN interface and is connected to the ONU #n via the LAN. A frame transmitted from the LAN interface by the user side communication device 14-n is transferred to the LAN interface unit 132 of the ONU #n via the LAN 17-n. Further, this frame is transmitted from the PON interface 131 of the ONU #n, transferred to the PON interface of the OLT 11 via the PON, and further transferred to the upstream device of the OLT 11.

  A frame transferred from the upstream device of the OLT to the OLT is transmitted from the PON interface of the OLT and transferred to the PON interface of the ONU via the PON. Further, the frame is transmitted from the LAN interface of the ONU, transferred to the LAN interface of the user side communication device via the LAN, and received by the user side communication device.

  In the PON system 1 described above, “PON sleep control” that restricts communication between the ONU #n and the OLT 11 is employed in order to reduce the power consumption of the ONU #n. In this PON sleep control, by shifting to a “sleep mode” in which communication is temporarily stopped, power consumption related to the PON interface, which is an ONU interface connected to ONU #n, can be reduced. The sleep mode includes an “uplink sleep mode” that temporarily stops upstream communication from the ONU to the OLT but does not stop downstream communication from the OLT to the ONU, and “bidirectional” that temporarily stops communication in both directions. There is "sleep mode".

  The PON interface unit 131 transmits / receives a signal for performing PON sleep control to / from the OLT 11, manages state transitions related to the PON sleep control, and is a circuit in the PON interface unit 131 based on the state. Reduce power consumption.

  On the other hand, the LAN interface unit 132 transmits / receives a signal for performing the LAN low power control to / from the user side communication device 14-n, manages the state transition related to the LAN low power control, and based on the state. The power consumption in the circuit in the LAN interface unit 132 is reduced. More specifically, LAN low power control standardized as IEEE 802.3az is adopted in order to save power in circuits related to each LAN interface of the ONU #n and the user side communication device 14-n. By shifting to the low power mode, the power consumption related to the LAN interface can be reduced.

  In the ONU #n according to the present embodiment, the LAN interface unit 132 further shifts from the normal reception state in which the LAN interface does not stop the function of receiving a frame to the low power reception state by the LAN low power control, or The PON interface unit 131 is notified by the LAN sleep notification signal a that the LAN interface has received the sleep signal from the user side communication device 14-n in the normal reception state.

  In the ONU #n according to the present embodiment, when the LAN sleep notification signal a output from the LAN interface unit 132 is input to the PON interface unit 131, the sleep request signal transmission waiting state is changed from the normal state based on this signal. And, further, transition to an upstream sleep state by transmission of an upstream sleep request signal, or transition to a bidirectional sleep state by transmission of a bidirectional sleep request signal.

  In addition, the LAN interface unit 132 has received the idle signal from the user side communication device when the LAN interface has shifted from the low power reception state to the normal reception state by the LAN low power control or when the LAN interface is in the low power reception state. This is notified to the PON interface unit 131 by the LAN wakeup notification signal b.

  When the LAN wakeup notification signal b output from the LAN interface unit 132 is input to the PON interface unit 131, the PON interface of the ONU #n waits for a wakeup request signal transmission from the upstream sleep state or the bidirectional sleep state. It shifts to a state, and further shifts to a normal state by transmission of a wake-up request signal.

FIG. 3 is a functional block diagram illustrating a configuration example of the ONU described above.
The ONU is related to the function of receiving and transferring frames, from the side closer to the host device, the optical transmission / reception unit (TRx transmission / reception unit) 1212 that converts the optical signal in the PON section and the electrical signal in the ONU, MPCP (Multipoint Control Protocol). ) PON signal processing unit 1313 that performs control frame transmission / reception processing and synchronization processing, BRG unit 133 that performs MAC (Media Access Control) processing and bridging processing, and temporarily stores downlink frames and uplink frames, , And a user network interface (UNI) 1322 serving as an interface with a user network (LAN).

  Further, a state control unit 1311 that manages and controls the state transition related to the PON sleep control of the PON interface unit 131 and a state control unit 1321 that manages and controls the state transition related to the LAN low power control of the LAN interface unit 132 are provided. I have.

In this embodiment, the LAN interface unit 132 corresponds to a “first interface” connected to the user-side communication apparatus via the user network in the present invention, and the PON interface unit 131 is connected to the OLT via the PON. This corresponds to the “second interface” connected to
The UNI unit 1322 constituting the LAN interface unit 132 receives a frame from the user-side communication device according to the present invention, and at least a part of the frame received from the OLT by the second interface (PON interface unit 131). This corresponds to a “first transmitter / receiver” that transmits to the user-side communication device.

  In addition, the first interface (LAN interface unit 132) receives a sleep signal indicating that the user side communication device is in a low power transmission / reception state that limits the function of transmitting a frame to reduce power consumption related to frame transmission. Then, the function of receiving the frame of the first transmission / reception unit (UNI unit 1322) is temporarily stopped, and the first interface (LAN interface unit 132) can receive the low power to reduce the power consumption of the first interface. This corresponds to a “first state control unit” that is in a state (LAN low power reception state).

  The optical transmission / reception unit 1312 included in the PON interface unit 131 mutually converts an optical signal and an electrical signal, receives a frame from the OTL, and the first interface (LAN interface unit 132) communicates with the user side. The state control unit 1311 corresponds to a “second transmission / reception unit” that transmits at least a part of a frame received from the device to the OLT. The state control unit 1311 receives a sleep signal from the first interface (LAN interface unit 132) or a low level. In response to the power reception state, the function of transmitting the frame of the second transmission / reception unit (optical transmission / reception unit 1312) is stopped, and the second interface (PON interface unit 131) is connected to the second interface. This corresponds to a “second state control unit” that sets a sleep state in which power consumption can be reduced.

  Note that the ONU according to the present embodiment, as will be described later, is triggered by the fact that the first interface (LAN interface unit 132) receives a sleep signal or enters a low power reception state. (PON interface unit 131) is set to a sleep state in which the power consumption of the second interface can be reduced, and in the same way as a conventional ONU, based on an instruction from the OLT, or the ONU itself is at least up or down. By monitoring one of the traffics, the PON interface unit 131 and the LAN interface unit 132 can be shifted to a sleep state and a low power transmission / reception state, respectively.

  The processing by the various functional units described above is realized by the cooperation of an arithmetic device (CPU: Central Process Unit) including a storage device and a computer program.

Note that the LAN sleep notification signal and the LAN wake-up notification signal can be implemented as a single LAN wake-up / sleep notification signal. In this case, the value of the LAN wake-up / sleep notification signal is 0. The time point when the value changes to 1 can be used as the LAN wakeup notification signal, and the time point when the value of the LAN wakeup / sleep notification signal changes from 1 to 0 can be used as the LAN sleep notification signal.
In addition, when the PON interface unit 131 implements PON sleep control as software that operates on the internal CPU, it is also possible to implement a LAN wakeup notification signal and a LAN sleep notification signal as interrupt signal lines to the CPU. It is.

[Operation of ONU]
Next, the operation of ONU #n according to the present embodiment will be described with reference to FIG. 4 and FIG.

[Transition sequence from normal mode to sleep mode]
FIG. 4 shows the state between the user-side communication device 14-n (hereinafter sometimes referred to as “UT #n”) and ONU #n in the “normal mode” (M3) to the “low power idle mode” (M4). It is a sequence diagram which shows a mode that between OLT11-ONU #n transfers to the state of "upstream sleep mode (M2)" from the state of "normal mode" (M1) in connection with changing to the state of this.
In the present embodiment, as described above, “sleep mode” includes “uplink sleep mode” and “bidirectional sleep mode”. In the following description, for the sake of convenience, the case of shifting to the “uplink sleep mode” will be described as an example. However, even in the case of shifting to the “bidirectional sleep mode”, the sequence is essentially the same.
Here, “the state between the OLT 11 and the ONU #n is in the normal mode (M1) state” means that the frame can be transmitted and received between the OLT 11 and the ONU #n. “M2) state” means that the transmission function of the upstream frame from ONU #n to OLT 11 is limited in order to reduce the power consumption of ONU #n.

  Similarly, “the state between UT #n and ONU #n is in the normal mode (M3)” means that a frame can be transmitted and received (particularly, an uplink frame is transmitted) between UT #n and ONU #n. Means that In addition, “between UT #n and ONU #n is in the low power idle mode (M4) state” means that the function of frame transmission / reception (especially uplink frame transmission) between UT #n and ONU #n. This means that the power consumption related to the transmission of the frame can be reduced.

As shown in FIG. 4, when the communication from the user side communication device #n to the ONU #n is in the “normal mode” (M3) by the LAN low power control, the LAN interface of the UT #n The LAN interface unit 132 of the ONU #n is in the “normal reception state” (S21) that does not restrict the function of receiving frames.
At this time, when the OLT 11 and the ONU #n are in the “normal mode” (M1) state in the PON sleep control, the PON interface unit 131 of the ONU #n does not restrict the function of transmitting a frame “normal state” ( S11).

  Here, the LAN interface of UT #n transmits or receives a frame from the “normal transmission state” (S31) through the “sleep signal transmission state” (S32) of time Ts for transmitting the sleep signal to ONU #n. It is assumed that the function to be performed is shifted to a “low power transmission / reception state” (S32) in which power consumption related to frame transmission / reception is reduced. For example, IEEE so-called “Deep Sleep” is an example of this “low power transmission / reception state”. The transition process to the low power transmission / reception state follows, for example, a protocol defined in IEEE 802.3az.

Such an event occurs, for example, when the user of UT #n performs an operation of user-side communication device #n performed to disconnect the phone when UT #n is an IP telephone terminal device. In this case, the LAN interface of UT #n transmits a frame corresponding to SIP BYE requesting the end of the session to ONU #n, and sends a response to the frame from the outside (for example, a SIP server) via ONU #n. When a frame corresponding to SIP 200 OK is received, the LAN interface of UT #n shifts from the normal transmission state (S31) to the sleep signal transmission state (S32).
This occurs when UT #n receives a frame corresponding to SIP BYE indicating the disconnection of the telephone from the outside (for example, a SIP server) to UT #n via ONU #n. In this case, the LAN interface of UT #n transmits a frame corresponding to SIP 200 OK to ONU #n as a response to this frame.

  As described above, when it is determined that the LAN interface of UT #n does not perform communication, the LAN interface shifts to the “sleep signal transmission state” (S32) in which the sleep signal is transmitted by the LAN low power control, so After a “sleep signal” indicating that the state is to be changed to the transmission / reception state is transmitted to the ONU #n, the state is changed to the “low power transmission / reception state” (S33).

  On the other hand, the LAN interface unit 132 of the ONU #n reduces power consumption instead of not receiving the frame received from the UT #n when the sleep signal is received from the UT #n in the normal reception state (S21). The process proceeds to the “low power reception state” (S22).

  At this time, the LAN interface unit 132 of the ONU #n receives the sleep signal from the UT #n in the normal reception state or the transition from the normal reception state to the low power reception state by the LAN sleep notification signal a. The PON interface unit 131 is notified.

  The PON interface unit 131 of the ONU #n receives the LAN sleep notification signal a, so that the LAN interface unit 132 has received the sleep signal from the UT #n in the normal reception state, or the low power reception from the normal reception state. Triggered by the transition to the state, a signal (upstream sleep request signal) for requesting the transition to the upstream sleep mode from the “normal state” (S11) to the OLT can be transmitted (from the OLT). The process proceeds to the “sleep request signal transmission wait state” (S12) in which the GATE signal is received and waits until the transmission time indicated by the GATE signal is reached, and further, the “upstream sleep state” ( The process proceeds to S13).

  According to the ONU according to the present embodiment, the sleep signal indicates that the LAN interface of UT #n is in a low power transmission / reception state in which the function of transmitting a frame is limited to reduce power consumption related to frame transmission. When notified to the n LAN interface units 132, the LAN interface unit 132 is set in the low power reception state, and the PON interface unit 131 connected to the PON is set in the sleep state in response to the notification.

  Therefore, after the LAN interface unit 132 enters the “low power reception state” (S22), when the PON interface unit 131 is set to the sleep state, the time Ti is used to avoid the adverse effect on the communication application due to the suspension of communication. During this period, there is no need to monitor communication. Therefore, it is possible to shorten the time until the PON interface unit 131 enters the “sleep state” (S13). As a result, the effect of reducing the power consumption of the ONU by the sleep control of the PON interface can be improved.

  Here, when UT #n transmits the last frame to end communication to the ONU, the user equipment notifies the ONU of the LAN low power control message, and the ONU shifts to the sleep mode according to the notification. ONU method (see FIG. 4) and ONU #n monitor the frame transfer status from the user side communication device (UT #n) to the OLT, and the frame transfer is not longer than the monitoring time Ti. Compared with the conventional method (see FIG. 5), which shifts to the sleep mode.

Assume that the monitoring time Ti is 30 seconds, which is a TCP session timeout, and that a keep-alive frame that periodically notifies that the UT is connected to the server is transmitted at 1-minute intervals. By sending keep-alive frames, the sleep mode is restored once per minute. However, in the conventional method, the monitor mode Ti cannot be shifted to the sleep mode for 30 seconds, and the remaining 30 seconds of sleep. It becomes.
On the other hand, in the ONU method according to the present embodiment, it is determined whether the user equipment is a keep alive frame or a frame for starting a call. Since it is possible to shift to the mode, it is possible to sleep for approximately 1 minute, and it is possible to double the sleep time.

  As described above, the ONU according to the present embodiment links the low power control of the two networks, LAN and PON, which relays the ONU, and triggered the start of low power from the user side communication device (UT). It is characterized by not only reducing the power consumption of the LAN interface but also reducing the power consumption of the PON interface.

  In other words, the ONU according to the present embodiment is the PON and the LAN in that the PON and the LAN are independent low power control, that is, the PON sleep control and the LAN low power control are linked. The low power control of each of the PON interface unit is significantly different from the conventional technology that is independent of each other, and the LAN low power control signaling from the user side communication device (UT) is used for the PON low power control. It can be said that low power is achieved.

The ONU according to the present embodiment performs communication during the time Ti by setting the PON interface unit 131 to the sleep state in conjunction with the LAN interface unit 132 being in the “low power reception state” (S22). Without monitoring, the PON interface unit 131 is put in the sleep state to improve the power saving effect.
In particular, when there is no need to monitor the presence or absence of communication in the user side communication device (UT), a high power saving effect can be obtained by putting the PON interface unit 131 in the sleep state at an earlier timing.

In general, the monitoring time Ti of a normal ONU that does not read the contents of the frame due to the difference in the monitoring level of the user side communication device (UT) that monitors at the upper level of the network hierarchy and the ONU that is a layer 2 device. In comparison with the above, the monitoring time Ti of the user side communication device (UT) that reads and monitors the contents of the frame is longer.
However, both the user side communication device (UT) and the ONU monitor the presence / absence of communication, and the monitoring time until entering the low power mode is shorter for the ONU than for the user equipment (UT). In this case, since the PON interface unit 131 can be shifted to the sleep mode earlier, power saving can be achieved even when both the user side communication device (UT) and the ONU monitor the presence / absence of communication. Can be expected.

[Other transition sequences from normal mode to sleep mode]
In the description of the present embodiment described above, the ONU #n PON is triggered by the transition of the LAN interface unit 132 of the ONU #n from the “normal reception state” (S21) to the “low power reception state” (S22). It is assumed that the interface unit 131 shifts from the “normal state” (S11) to the “sleep request signal transmission waiting state” (S12). However, the PON interface unit 131 of the ONU #n changes from the “normal state” (S11) to the “sleep state”. Various modifications can be made to the sequence of shifting to the “request signal transmission waiting state” (S12).

  As an example, the LAN interface unit 132 of the ONU #n shifts from the “normal reception state” (S21) to the “low power reception state” (S22), and the ONU #n (specifically, the upstream buffer 135). ) The sequence in which the PON interface unit 131 of the ONU #n shifts from the “normal state” (S11) to the “sleep request signal transmission waiting state” (S12) when all the upstream frames stored in () are sent to the OLT 11. Is possible.

  This is because if the PON interface unit 131 of the ONU #n shifts to the “upstream sleep state” (S13) in a state where frames are accumulated in the ONU #n, the amount of time that the upstream sleep state continues. , The frame transfer from the ONU #n to the OLT 11 is delayed, and there is a possibility that the communication quality may be deteriorated. However, according to the other sequence described above, the uplink frame transfer delay associated with the PON sleep control Therefore, there is an effect that power consumption can be reduced while maintaining communication quality.

[Return sequence from sleep mode to normal mode]
Next, a return sequence from the sleep mode to the normal mode will be described.

  FIG. 5 shows that the state between the OLT 11 and the ONU #n is the “uplink sleep mode” (M2) by the PON sleep control, and the communication from the user side communication device #n to the ONU #n is performed by the LAN low power control. In the “low power idle mode” (M4) state, the flow of frames when starting transmission of a frame transmitted by the user side communication device (UT) #n to the higher-level device of the OLT 11, and each device It is a sequence diagram showing the change of the state of.

When the OLT 11 and the ONU #n are in the “uplink sleep mode” (M2) state by the PON sleep control, the PON interface unit 131 of the ONU #n is in the “transmission sleep state” (S13). When the communication from the user side communication device #n to the ONU #n is in the “low power idle mode” (M4) state by the LAN low power control, the transmission side LAN interface of the UT #n (S33), and the receiving-side LAN interface unit 132 of the ONU #n is in the “low power reception state” (S22).
The signal between the transmission-side LAN interface of UT #n and the reception-side LAN interface unit 132 of ONU #n is alternately repeated with a time Tq for stopping transmission and reception and a time Tr for transmitting and receiving a refresh signal, Communication is performed intermittently in the low power idle mode.

  Here, the transmission side LAN interface of the UT #n transmits the frame from the “low power transmission / reception state” (S33) through the “idle signal transmission state” (S34) of the time Tw for transmitting the idle signal to the ONU #n. The process proceeds to the “normal transmission state” (S35), which is a state in which transmission to ONU #n is possible, and the frame is transmitted to ONU #n.

  The transition from the “low power transmission / reception state” to the “normal transmission state” through the “idle signal transmission state” is triggered by, for example, the operation of UT #n performed by the user of UT #n to make a call. As UT #n. In this case, the LAN interface of UT #n transmits a frame corresponding to SIP INVITE requesting the start of the session to ONU #n.

In addition, the state transition described above indicates that UT #n has received a frame corresponding to SIP INVITE indicating that a call has been received from outside (for example, a SIP server) to UT #n via ONU #n. As an opportunity, UT #n performs.
In this case, the LAN interface of UT #n transmits to ONU #n a frame corresponding to SIP 180 Ringing, which is a response signal indicating that the call is in progress. As described above, the LAN interface of the user side communication device #n repeats the low power transmission / reception state and the transmission refresh state by the LAN low power control during the period in which communication is not performed, and is low when frame transmission is required. From the power transmission / reception state, the idle signal is transmitted to the ONU #n for a certain period of time, then the normal transmission state in which the frame can be transmitted to the ONU #n is entered, and the frame is transmitted to the ONU #n. .

  On the other hand, the LAN interface of ONU #n is a “normal reception state” in which a frame transmitted from UT #n can be received in response to reception of an idle signal from UT #n in “low power reception state” (S22). The process proceeds to (S23), and the frame transmitted from UT #n is received.

  At this time, the LAN interface unit 132 of the ONU #n receives the idle signal from the UT #n or the PON interface unit using the LAN wakeup notification signal b that the low power reception state has been shifted to the normal reception state. 131 is notified.

  Upon receiving the LAN wakeup notification signal b, the PON interface unit 131 of ONU #n receives a signal (a wakeup request) for requesting the OLT to return to the normal mode from the “upstream sleep state” (S13). Signal) until it becomes possible to transmit (until the GATE signal from the OLT is received and the transmission time indicated by the GATE signal is reached), the state shifts to a “wake-up request signal transmission waiting state” (S14), and further a wake-up request By transmitting the signal, the process proceeds to the “normal state” (S15). Further, the PON interface unit 131 of the ONU #n that has shifted the frame transmitted from the UT #n received by the LAN interface unit 132 of the ONU #n to the normal state receives the GATE signal from the OLT 11 and receives the GATE signal. Send based on.

[Other transition sequences from sleep mode to normal mode]
In the description of the present embodiment described above, the ONU #n PON is triggered when the LAN interface unit 132 of the ONU #n shifts from the “low power reception state” (S22) to the “normal reception state” (S23). The interface unit 131 is assumed to shift from the “upstream sleep state (transmission sleep state)” (S13) to the “wakeup request signal transmission wait state” (S14), but the ONU #n PON interface unit 131 is “uplink Various modifications can be made to the sequence of shifting from the “direction sleep state (transmission sleep state)” (S13) to the “wake-up request signal transmission wait state” (S14).

  As an example, the LAN interface unit 132 of the ONU #n is transmitted from the user side communication device #n within the time Twf after the transition from the “low power reception state” (S22) to the “normal reception state” (S23). A sequence in which the PON interface unit 132 of the ONU #n shifts from a transmission sleep state to a wake-up request signal transmission waiting state when a frame is received by Lwf bytes or more is possible.

  Even if the PON interface unit 131 of the ONU #n is in the “upstream sleep state (transmission sleep state)” (S13), if the frame is less than a predetermined Lwf byte, the ONU #n is within the time Twf. When the frame can be transmitted from the OLT to the OLT, a frame less than Lwf bytes (for example, a frame transmitted by the user-side communication device #n to maintain registration with the SIP server) is transmitted to the user-side communication device #n. Since the PON interface unit 131 of the ONU #n can transfer the frame to the OLT 11 while maintaining the transmission sleep state when transmitting from the network, there is an effect that power consumption related to the PON interface unit 131 can be reduced.

  In the above sequence, the ONU #n LAN interface unit 132 shifts from the “low power reception state” (S22) to the “normal reception state” (S23) and then the ONU #n PON interface unit 131 Direction sleep state (transmission sleep state) ”(S13) to“ normal state ”(S15), there is a delay, and this delay causes the LAN interface unit 132 in the normal reception state of ONU #n. There is a period during which a frame received from the received UT #n cannot be transmitted from the PON interface unit 131 of the ONU #n that has not been shifted to the normal state. Frames received during this period are held in ONU #n, but because the buffer capacity of ONU #n is limited, all received frames cannot be held in ONU #n and are discarded. Frames may occur.

  Therefore, in order to prevent the frame from being discarded, flow control standardized as IEEE 802.3x for stopping frame transmission from the user-side communication device #n to the ONU #n is performed. Specifically, the ONU #n transmits a pause frame to the user-side communication device #n when the number of frames or the amount of data held in the ONU #n becomes a predetermined amount or more. In addition, when ONU #n has a plurality of queues and the queue in which the frames are stored is selected according to the priority described in the header of the frame from user side communication device #n to ONU #n. Since the frame hold status in the ONU #n differs depending on the frame priority, IEEE 802.1Qbb is used to stop frame transmission from the user side communication device #n to the ONU #n according to the priority. It is also possible to perform standardized flow control.

  The release of flow control (transmitting a pause frame indicating release of flow control from the user side communication device #n to the ONU #n) is performed by the PON interface unit 131 of the ONU #n in the “upstream sleep state (transmission sleep state)” ”(S13) to the“ normal state ”(S15), or the frame held in the ONU #n by the transition to the“ normal state ”(S15) is transmitted to the OLT, and the amount is reduced. When the amount becomes less than the amount that can be judged to be no longer discarded.

  In the above sequence, when the LAN interface unit 132 of ONU #n shifts from the “low power reception state” (S22) to the “normal reception state” (S23), the flow control controls UT #n to ONU #n. Frame transmission is stopped (that is, a pause frame is transmitted to the user-side communication device #n), and the PON interface unit 131 of the ONU #n changes from “upstream sleep state (transmission sleep state)” (S13) to “normal”. It is also possible to cancel the flow control at the time of shifting to the “state” (S15).

  Further, the flow control is canceled before the time when the PON interface unit 131 of the ONU #n shifts from the “upstream sleep state (transmission sleep state)” (S13) to the “normal state” (S15). Thus, when the PON interface unit 131 enters the “normal state” (S15), the upstream frames transmitted after the UT #n cancels the flow control are stored in the ONU #n. The ONU #n can transmit the upstream frame to the OLT immediately after the state becomes normal.

  In this embodiment, the case where UT #n is an IP telephone terminal has been described as an example, but communication from UT #n to ONU #n is started even with other terminal devices. When the first frame is transmitted, the state transition sequence of the user side communication device #n and ONU #n described in the present embodiment can be adopted.

  For example, one example of the UT #n is a home gateway. One or more home communication terminals are connected to the home gateway, and a signal transmitted from the home communication terminal is transferred as a frame to the ONU #n. The frame received from n is transmitted as a signal to this home communication terminal. In this case, an example of the opportunity when the LAN interface (interface connected to the ONU #n via the LAN) of the user side communication device #n (home gateway) shifts from the low power transmission / reception state to the normal transmission state is shown in this home gateway. The home gateway receives the signal transmitted from the home communication terminal connected to the network, and the signal needs to be transmitted to the ONU #n as an upstream frame.

  Another example is that application software running on the CPU mounted on the home gateway has entered an active state that requires frame transmission / reception.

  In the present embodiment, the case where the OLT 11 and the ONU #n are in the upstream sleep mode by the PON sleep control has been described. However, the same sequence can also be adopted in the bidirectional sleep mode. Note that when the bidirectional sleep mode is set by the PON sleep control, the ONU #n from the ONU #n during the bidirectional sleep mode is controlled by the LAN low power control in the downlink direction from the ONU #n to the user side communication device #n. Communication to the user-side communication device #n can be set in the low power mode.

  As described above, according to the ONU according to the present embodiment, the LAN interface unit 132 receives the sleep signal and the idle signal notified from the user side communication device to the ONU for the LAN low power control. By passing the LAN sleep notification signal a and the LAN wakeup notification signal b from the LAN interface unit 132 to the PON interface unit 131, it is possible to shift to the sleep mode by the PON sleep control or the normal mode by the PON sleep control. It is possible to reflect the necessity of the transition to the PON sleep control with a low delay.

  The present invention can be used for a communication system using a PON system such as FTTH (Fiber To The Home).

  DESCRIPTION OF SYMBOLS 1 ... PON system, 11 ... OLT, 12 ... Optical branch coupler, 13-1 to 13-n ... ONU, 14-1 to 14-n ... User side communication apparatus, 15, 16-1 to 16-n ... Optical Fibers, 17-1 to 17-n ... LAN, 131 ... PON interface unit, 132 ... LAN interface unit.

Claims (6)

Power consumption related to transmission / reception of frames by being connected to a user-side communication device via a user network, transmitting / receiving frames to / from the user-side communication device, and restricting functions of the user-side communication device to transmit / receive frames A first interface that is in a low power transmission / reception state capable of reducing power consumption by limiting a function of transmitting or receiving a frame when receiving a sleep signal indicating that the low power transmission / reception state is reduced;
Connected to the station side optical line terminator through the passive optical network, and converts the optical signal and the electrical signal to each other to transmit / receive a frame to / from the station side optical terminator and to transmit / receive the frame A second interface capable of entering a sleep state capable of limiting and reducing power consumption,
Said second interface, Ri Do and the sleep state that the first interface becomes a sleep signal or that the low power transceiver state has been received as a trigger,
The first interface is:
A first transmission / reception unit that receives a frame from the user-side communication device and transmits at least a part of the frame received by the second interface from the station-side optical terminal device to the user-side communication device;
When the first interface receives a sleep signal indicating that the user side communication device is in a low power transmission / reception state that limits a function of transmitting or receiving a frame to reduce power consumption related to frame transmission / reception, the first interface receives the sleep signal. A first state control unit that limits a function of transmitting or receiving a frame of one transmission / reception unit and sets the first interface to a low-power transmission / reception state capable of reducing power consumption of the first interface; Including
The second interface is:
An optical signal and an electrical signal are mutually converted to receive a frame from the station side optical termination device, and at least a part of the frame received by the first interface from the user side communication device is converted to the station side light. A second transceiver for transmitting to the line termination device;
When the first interface receives the sleep signal or enters the low power transmission / reception state, the function of transmitting or transmitting / receiving a frame of the second transmission / reception unit is limited, and the second interface A user-side optical line termination device comprising: a second state control unit that sets an interface to a sleep state in which power consumption of the second interface can be reduced . In the user side optical network unit according to claim 1,
Furthermore, a buffer for holding a frame to be transmitted to the station side optical termination device is provided,
The second state controller is
The second interface is set in the sleep state after the first interface is set in the low power transmission / reception state and the amount of frames held in the buffer becomes equal to or less than a predetermined value. An optical line termination device on the user side. In the user side optical network unit according to claim 1 or 2,
The first state control unit further includes:
When the first interface in the low power transmission / reception state receives an idle signal indicating that the user side communication device is in a normal transmission / reception state that does not restrict a function of transmitting or receiving a frame from the low power transmission / reception state, The first interface is set to a normal transmission / reception state in which the first transmission / reception unit does not restrict a function of transmitting or receiving a frame with the user-side communication device from the low power transmission / reception state,
The second state controller is
When the first interface receives the idle signal or when the low power transmission / reception state is changed to the normal transmission / reception state, the second transmission / reception unit transmits a frame from the sleep state to the second transmission / reception unit. A user-side optical line termination device characterized by having a normal transmission / reception state in which a function of transmitting or transmitting / receiving is not restricted . Power consumption related to transmission / reception of frames by being connected to a user-side communication device via a user network, transmitting / receiving frames to / from the user-side communication device, and restricting functions of the user-side communication device to transmit / receive frames A first interface that is in a low power transmission / reception state capable of reducing power consumption by limiting a function of transmitting or receiving a frame when receiving a sleep signal indicating that the low power transmission / reception state is reduced;
Connected to the station side optical line terminator through the passive optical network, and converts the optical signal and the electrical signal to each other to transmit / receive a frame to / from the station side optical terminator and to transmit / receive the frame A second interface capable of entering a sleep state capable of limiting and reducing power consumption;
With
The first interface is:
A first transmission / reception unit that receives a frame from the user-side communication device and transmits at least a part of the frame received by the second interface from the station-side optical terminal device to the user-side communication device;
The first interface that is in a low power transmission / reception state capable of reducing power consumption by restricting the function of transmitting or receiving frames restricts the function of the user side communication device to transmit or receive frames and transmits / receives frames. When receiving an idle signal indicating that a normal transmission / reception state in which a function of transmitting or receiving a frame is not restricted is received from a low-power transmission / reception state that reduces power consumption related to the first interface, the first interface is changed from the low-power transmission / reception state to the A first state control unit that sets a normal transmission / reception state in which the first transmission / reception unit does not restrict a function of transmitting or receiving a frame with the user-side communication device;
With
The second interface is:
An optical signal and an electrical signal are mutually converted to receive a frame from the station side optical termination device, and at least a part of the frame received by the first interface from the user side communication device is converted to the station side light. A second transceiver for transmitting to the line termination device;
When the first interface receives the idle signal or when the low power transmission / reception state is changed to the normal transmission / reception state, the second transmission / reception unit transmits a frame from the sleep state to the second transmission / reception unit. A second state control unit that sets a normal transmission / reception state without limiting a function of transmitting or transmitting
User optical network unit, characterized in that it comprises a. A first interface connected to the user-side communication device via the user network, a second interface connected to the station-side optical line termination device via the passive optical network, and the station-side optical termination device A buffer for holding the frame, wherein the first interface transmits at least part of the frame received from the user side communication device to the station side optical line termination device from the second interface, and the second interface In the power consumption control method for a user-side optical line terminator, wherein an interface transmits at least a part of a frame received from the station-side optical terminator from the first interface to the user-side communication device.
The first interface receives a sleep signal indicating that the user side communication device is in a low power transmission / reception state that limits a function of transmitting or receiving a frame to reduce power consumption related to frame transmission or reception. When,
The first interface that has received the sleep signal restricts the function of transmitting or receiving a frame from the normal transmission / reception state in which the function of transmitting or receiving a frame with the user-side communication device is not restricted, and the first interface A step of setting a low power transmission / reception state capable of reducing power consumption of the interface;
When the first interface receives the sleep signal or enters the low power transmission / reception state, the function of transmitting or transmitting / receiving a frame of the second transmission / reception unit is limited, and the second interface Setting the interface to a sleep state capable of reducing power consumption of the second interface,
The step of setting the second interface to the sleep state includes:
After the first interface enters the low power transmission / reception state and the amount of frames held in the buffer falls below a predetermined value, the second interface enters the sleep state.
A power consumption control method for a user side optical network unit. In the power consumption control method of the user side optical line termination device according to claim 5,
Receiving an idle signal indicating that the first interface in the low power transmission / reception state is in a normal transmission / reception state in which the user-side communication device does not restrict a function of transmitting or receiving a frame from the low power transmission / reception state; When,
Setting the first interface that has received the idle signal to a normal transmission / reception state that does not limit a function of transmitting or receiving a frame with the user-side communication device from the low-power transmission / reception state;
A function of transmitting or transmitting / receiving a frame from the sleep state to the second interface when the first interface has received the idle signal or has changed from the low power transmission / reception state to the normal transmission / reception state. Steps for normal transmission / reception without restriction
A power consumption control method for a user-side optical line terminator.

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