JP5975825B2 - Slave station apparatus and power saving control method - Google Patents

Description

  The present invention relates to a slave station apparatus 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.

  As one of the power saving methods, there is a method in which the communication device a and the communication device b cooperate with each other while exchanging mutual device information (information indicating the presence / absence of data to be transmitted).

  An operation in a method in which the communication device a and the communication device b cooperate with each other while exchanging device information will be described. Assume that the communication device a shifts to the power saving state. When the communication device a does not hold data to be transmitted to the communication device b and it is not necessary to transmit / receive a signal, the communication device a transmits a power saving start request notification to the communication device b. Similarly, the communication device b that has received the power saving start request notification does not hold the data to be transmitted to the communication device a, and if the transmission / reception of the signal is not required, the communication device b transmits to the communication device a. , A power saving start instruction including information on the duration of the operating state (T11) and the duration of the power saving state (T12) is transmitted (however, if T11 and T12 are determined in advance) Is not included in the power saving start instruction). Upon receiving this power saving start instruction, the communication apparatus a operates in a cycle according to the designated durations T11 and T12 after the response to the power saving start instruction is transmitted to the communication apparatus b and after the processing delay time has elapsed. The state and the power saving state are repeated alternately. In the time zone of T11 (that is, in the operating state), the communication device a and the communication device b perform connectivity confirmation between the communication devices and exchange of transmission waiting data. In the time period T12 (that is, in the power saving state), the function for performing processing related to signal transmission / reception is stopped.

  Another example of the power saving method will be described. Assume that the communication device a shifts to the power saving state while exchanging device information with the communication device c. The communication device c periodically notifies the communication device a of information regarding the presence / absence of transmission-waiting data (notification at time interval T13). When the communication device a receives information indicating no data waiting for transmission, the communication device a shifts to a power saving state after the processing delay time has elapsed. Moreover, the connectivity between the communication device a and the communication device c is confirmed by periodically notifying information on the presence / absence of data waiting to be transmitted.

  In these power saving methods, after the transition to the power saving state, the transmission / reception of the data waiting for transmission is performed at a predetermined timing, and when there is data waiting for transmission, the normal operation state (non-power saving state) is promptly entered. It is premised on the transition.

  There is also a technology for performing power saving control without exchanging device information between communication devices (for example, Patent Documents 1 and 2).

  In Patent Document 1, even when information is not exchanged between communication devices, by transmitting a Dying Gasp before shifting to the power saving state, the link is broken due to a device failure or the like due to a power failure control or the like. A technique for making it possible to discriminate between the two is disclosed.

  In Patent Document 2, even when information is not exchanged between communication devices, some processing blocks (protocol control unit, bridge unit, and PHY unit) are stopped when there is no signal transmission / reception. A technique for realizing power saving is disclosed.

JP 2011-103532 A JP 2011-114531 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, when the above conventional technology is applied, a power saving effect can be expected, but it is assumed that information is exchanged between communication devices, and information is exchanged with both communication devices that transmit and receive data. It is necessary to have the function of. For this reason, in order to obtain the power saving effect, there is a problem in that the connection of the communication device is restricted. That is, there is a problem that the power saving effect is obtained only when both of the communication devices used in combination have an information exchange function.

  The present invention has been made in view of the above, and an object of the present invention is to obtain a slave station 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 provides a slave station device that constitutes a communication system together with a master station device, and transmits and receives control signals and data signals to and from the master station device. Based on the communication contents after the link between the communication processing unit and the master station device is established, it is determined whether or not the master station device supports power saving control performed while exchanging control information between the devices. Based on the determination result, based on the first power saving mode in which the power saving state and the operation state are alternately switched in the cycle determined by the parent station device, or the reception result of the control signal transmitted from the parent station device A power saving mode selection unit that selects a second power saving mode that alternately switches between a power saving state and an operation state at a cycle determined in advance or a preset cycle, and the power saving mode selected by the power saving mode selection unit And a power saving controller for executing follow power saving control on the transmission function or a receiving function of the communication processing unit, or transmitting and receiving function, characterized in that it comprises a.

  According to the present invention, since the slave station device executes power saving control according to the function of the connection destination master station device, it can be avoided that the power saving control is not executed. The effect is that it is possible to realize efficient power saving control.

FIG. 1 is a diagram showing a configuration example of a first embodiment of a communication system according to the present invention. FIG. 2 is a chart showing an example of a power saving control method in cooperation between apparatuses. FIG. 3 is a chart showing an example of a method for ending power saving control in cooperation between apparatuses. FIG. 4 is a chart showing another example of the power saving control method linked between apparatuses. FIG. 5 is a diagram illustrating a configuration example of the ONU according to the first embodiment. FIG. 6 is a diagram illustrating a configuration example of the OLT according to the first embodiment. FIG. 7 is a diagram illustrating a configuration example of a communication terminal. FIG. 8 is a chart illustrating an example of communication between the ONU and the OLT according to the first embodiment. FIG. 9 is a flowchart of the operation corresponding to the chart shown in FIG. FIG. 10 is a flowchart illustrating an example of the power saving operation (power saving control operation performed without exchanging device information) according to the first embodiment. FIG. 11 is a diagram illustrating a method of determining the start time and duration of the power saving state. FIG. 12 is a flowchart illustrating an example of the power saving mode cancellation operation according to the first embodiment. FIG. 13 is a diagram illustrating a method for determining the hold time. FIG. 14 is a diagram illustrating a configuration example of an ONU according to the second embodiment. FIG. 15 is a chart diagram illustrating an example of ONU-OLT communication according to the third embodiment. FIG. 16 is a flowchart of the operation corresponding to the chart shown in FIG. FIG. 17 is a chart showing an example of ONU-OLT communication according to the fourth embodiment. FIG. 18 is a flowchart of the operation corresponding to the chart shown in FIG.

  Embodiments of a slave station apparatus 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 slave station device 10, a master station device 20, a communication terminal 30, and a communication terminal 40. In the following description, the slave station device is described as ONU (Optical Network Unit), and the master station device is described as OLT (Optical Line Terminal).

  The ONU 10 and the OLT 20 are connected by a transmission medium 1 including an optical fiber cable, an optical coupler, and the like. In addition, although the example provided with one ONU10 is given here, there may be a plurality of ONUs 10 connected to the OLT 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 ONU 10 via the transmission medium 2. The communication terminal 40 is an L2SW (Layer 2 Switch) or the like, and is connected to the OLT 20 via the transmission medium 3. One or more communication terminals 30 may be connected to the ONU 10. The transmission media 2 and 3 may be any media, but are LAN (Local Area Network) cables, for example. The OLT 20 is connected to the upper network via the communication terminal 40.

  In the present embodiment and each of the embodiments described later, the case where the communication system to which the present invention is applied is a GE-PON system will be described, but the present invention can also be applied to other communication systems, and transmission media. The transmission method is not limited to the GE-PON system.

  In the following description, the direction from the OLT 20 to the ONU 10 is referred to as the downlink direction, the direction from the ONU 10 to the OLT 20 is referred to as the uplink direction, data transmitted in the uplink direction is uplink data, and data transmitted in the downlink direction is This is called downlink data. When described as upper and lower data, uplink data and downlink data are indicated.

  Terms used in each embodiment will be briefly described. Power saving control refers to control in which a power saving state and an operation state are alternately repeated. A state in which power saving control is performed is referred to as a power saving mode. The power saving state indicates an operation state in which power consumption is reduced by stopping some or all functions (processing blocks) related to communication. The operation state indicates a normal operation state in which all functions related to communication are operated.

  Here, a conventional power saving control method linked between apparatuses will be described. FIG. 2 is a chart showing an example of a power saving control method in cooperation between apparatuses. The example of FIG. 2 is a method in which the communication device a starts power saving control while exchanging device information with the communication device b.

  Before starting the power saving control in cooperation with the communication device b, the communication device a performs parameter negotiation and exchanges parameter information (step S1). The parameter information is information used in power saving control, and is, for example, the duration of the power saving state. After the parameter information is exchanged, the communication device a monitors whether or not there is data to be transmitted to the communication device b (transmission waiting data), and if there is no transmission waiting data, requests the communication device b to start power saving control. A power saving start request notification is transmitted (step S2). The communication device b also monitors the presence / absence of data to be transmitted to the communication device a (transmission waiting data), and when there is no transmission waiting data to the communication device a when the power saving start request notification is received from the communication device a, In order to cause the communication device a to start power saving control, a power saving start instruction including the operation state time T11 and the power saving state time T12 is transmitted to the communication device a (step S3). Note that the communication device b may notify the times T11 and T12 in advance in the parameter negotiation in step S1. When T11 and T12 are notified in advance, the communication device b transmits a power saving start instruction that does not include T11 and T12.

  Upon receiving the power saving start instruction, the communication apparatus a transmits a power saving start instruction response to the communication apparatus b as a response thereto, and starts power saving control (step S4). Thereafter, when a processing delay time (corresponding to the “processing time” shown) elapses, the state shifts to a power saving state. Thereafter, the operation state (non-power-saving state) and the power-saving state are alternately repeated at a cycle specified by T11 and T12 until data transmission / reception is required. Between the communication device a and the communication device b, an exchange about the holding state of the transmission waiting data is performed. Specifically, the communication device b periodically transmits a transmission data inquiry for inquiring whether there is transmission waiting data (steps S5 and S6). The communication device “a” does not respond when it receives an inquiry about transmission waiting data in the power saving state (time period of T12) (case of step S5). On the other hand, when an inquiry about transmission waiting data is received in the operating state (time zone of T11), a transmission data response is returned as a response (case of step S7 with respect to step S6). In the example of FIG. 2, the communication device “a” does not hold the transmission waiting data, and responds to the inquiry in step S6 that there is no transmission waiting data in step S7. Thereafter, when the time T11 elapses, the state again shifts to the power saving state.

  FIG. 3 is a chart showing an example of a method for ending the power saving control started in accordance with the procedure shown in FIG. When the communication device a starts the power saving control, the communication device a repeats the operating state and the power saving state at a cycle specified by the time T11 of the operating state and the time T12 of the power saving state (step S11). The communication device a monitors whether or not transmission data to the communication device b is generated in both the operation state and the power saving state. When the transmission data is detected, the communication device a is saved after the processing delay time has elapsed. The power control is ended (step S12), and a transmission data response indicating that there is transmission waiting data is transmitted to the communication apparatus b as a response to the transmission data inquiry from the communication apparatus b, thereby transmitting to the communication apparatus b. It is notified that there is waiting data (step S13). Receiving this notification, the communication device b transmits a data transmission start instruction to the communication device a and notifies the communication device a to output data (step S14), and the communication device a responds to the data transmission start instruction. By transmitting a data output start notification to the communication device b, the data output is notified (step S15), and then the data is transmitted (step S16).

  Note that FIG. 3 shows an example of the case where the generation of transmission data is detected in the power saving state. However, when the generation of transmission data is detected in the operating state, the power saving control is immediately terminated, and the transmission waiting data is stored. It notifies the communication device b that there is. Moreover, although the operation | movement when transmission data generate | occur | produces in the communication apparatus a was shown, when the transmission data to the communication apparatus a generate | occur | produce in the communication apparatus b, the communication apparatus b notifies the communication apparatus a that there exists transmission data. Data is transmitted after notifying and terminating the power saving control. When the communication device b notifies that there is transmission data, the communication device a may be in a power saving state (it may not be possible to receive notification that there is transmission data). Until the message is returned, the notification that there is transmission data is repeated at a predetermined timing. When the transmission / reception of data ends, the communication devices a and b follow the procedure shown in FIG. 2 and start the power saving control again when the conditions are satisfied.

  FIG. 4 is a chart showing another example of the power saving control method linked between apparatuses. FIG. 4 shows an operation example when the communication device a that relays data between the communication device b and the communication device c starts the power saving control.

  In the power saving control method illustrated in FIG. 4, the communication device c notifies the communication device a of the presence / absence of transmission-waiting data. When receiving a notification that there is data waiting to be transmitted (step S21), the communication device a relays data transmitted thereafter to the communication device b (step S22). On the other hand, when a notification of no transmission waiting data is received from the communication device c (step S23), the communication device a decides to start the power saving control, and shifts to the power saving state after the processing delay time elapses. Even when there is no transmission data, the communication device c repeats the notification of the presence or absence of transmission waiting data at the determined time interval T13 (steps S24, S25, S26). In this way, the communication device a and the communication device c perform connectivity confirmation every time interval T13. When there is transmission-waiting data (step S26), the communication device a ends the power saving control, and the communication device c transmits data to the communication device a (step S27). On the other hand, between the communication device a and the communication device b, similarly to the operation described with reference to FIG. 3, the communication device b inquires whether there is transmission waiting data (step S11), and the communication device a transmits the transmission waiting data ( If there is data to be relayed from the communication device c to the communication device b), the communication device b is notified that there is data to be transmitted (step S13). Thereafter, the communication device a transmits data to the communication device b in the same procedure as steps S14 to S16 in FIG.

  In the power saving control method described with reference to FIGS. 2 to 4, power saving control is performed while exchanging device information (such as presence / absence of transmission data) between communication devices. For this reason, there are restrictions on the function of the communication device and the connection between the communication devices, and general-purpose power saving is difficult. On the other hand, in the present embodiment, power consumption of one communication apparatus can be reduced by the operation described below regardless of the function of the communication apparatus to be connected. Further, by dynamically determining each parameter used in power saving control, efficient power saving can be performed. Although FIGS. 2 to 4 show examples of exchanging information on the state of transmission-waiting data as device information, the device information to be exchanged is not limited to this. When information regarding the state of the apparatus is exchanged between communication apparatuses during power saving control, it is included in a power saving method linked between apparatuses.

  Next, the operation of the present embodiment will be described. In the communication system of the present embodiment shown in FIG. 1, the ONU 10 has a host device communication unit 11 communicating with the host OLT 20, a transition to the power saving state and a return to the operation state with respect to the host device communication unit 11. Power-saving control unit 12 for instructing, a memory unit 13 for holding various data, a lower-level device communication unit 14 for communicating with a lower-level communication terminal 30, and various processes including data writing and reading to the memory unit 13 And a data information monitoring unit 16 that monitors the status of data transmitted and received between the OLT 20 and the communication terminal 30.

  The OLT 20 is a host device communication unit 21 that communicates with a host communication terminal 40, a memory unit 23 that holds various data, a lower device communication unit 24 that communicates with a lower ONU 10, and data writing to and reading from the memory unit 23. And a data processing unit 25 that performs processing including

  The communication device 30 includes a host device communication unit 31 that communicates with the host ONU 10, a memory unit 33 that holds various data, and a data processing unit 35 that performs processing including writing and reading data to and from the memory unit 33. Yes.

  The communication device 40 includes a memory unit 43 that holds various data, a lower-level device communication unit 44 that communicates with the lower-order OLT 20, and a data processing unit 45 that performs processing including writing and reading data to and from the memory unit 43. Yes.

  In the communication system according to the present embodiment, the ONU 10 determines whether or not the OLT 20 has a power saving function when connected to the OLT 20. Specifically, the OLT 20 determines whether or not device information (such as presence / absence of transmission data) described as the power saving control method linked between the devices can be exchanged. That is, it is determined whether or not a power saving control method linked between apparatuses can be implemented. The ONU 10 selects a power saving control method linked between apparatuses when it is determined that it can be performed, and performs the following operation when it is determined that it cannot be performed. If it is determined that the power saving control method linked between the apparatuses cannot be implemented, the ONU 10 alternately executes and stops communication when there is no uplink data (transmission data to the OLT 20) and downlink data (data received from the OLT 20). To do. That is, the sleep time (the time for stopping communication with the transmission function in the power saving state) and the active time (the time for performing communication after returning from the power saving state) are alternately repeated. At this time, the sleep time, which is the duration of the power saving state, is determined so as to be the maximum within a range in which the link (logical connection) with the OLT 20 can be continued. The active time that is the duration of the operating state is determined to be the minimum. When uplink data or downlink data is generated, it immediately returns from the power saving state, and does not shift to the power saving state until the data transmission / reception processing is completed. Even when it is determined that the ONU 10 and the OLT 20 can execute the power saving control to switch to the power saving state while exchanging the device information, the ONU 10 exchanges the device information with the OLT 20 as a result of the above. A similar operation may be performed.

  FIG. 5 is a diagram showing a configuration example of the ONU 10 according to the present embodiment, and shows the configuration of the ONU 10 shown in FIG. 1 in more detail. As shown in FIG. 5, the ONU 10 includes a host device communication unit 11 that operates as a communication processing unit, a power saving control unit 12, a memory unit 13, a lower device communication unit 14, a data processing unit 15, and a power saving unit. A data information monitoring unit 16 that operates as a mode selection unit. The host device communication unit 11 includes an optical transmission unit 17, a transmission function unit 18, an optical reception unit 19, and a reception function unit 50. In FIG. 5, the data signal is indicated by a solid arrow line, and the control signal is indicated by a broken arrow line.

  The optical transmission unit 17 of the higher-level device communication unit 11 converts the data received from the transmission function unit 18 into an optical signal and outputs it to the transmission medium 1. The optical receiver 19 converts an optical signal received via the transmission medium 1 into an electrical signal, and outputs the converted electrical signal to the reception function unit 50. The transmission function unit 18 controls the light emission timing of the optical transmission unit 17 and generates a data string based on the data received from the data information monitoring unit 16. The reception function unit 50 extracts a data string from the data received from the optical reception unit 19 and outputs it to the data information monitoring unit 16.

  The host device communication unit 11 configured as described above performs data transmission / reception processing with the OLT 20 (see FIG. 1). The host device communication unit 11 supplies the downlink data received from the OLT 20 to the data information monitoring unit 16 in the reception operation of the downlink data transmitted from the OLT 20. The supplied downlink data is stored in the memory unit 13 from the data information monitoring unit 16 via the data processing unit 15. The downlink data held in the memory unit 13 is read by the data processing unit 15 and transmitted to the communication terminal 30 (see FIG. 1) via the data information monitoring unit 16 and the lower-level device communication unit 14. On the other hand, in the operation of transmitting the uplink data received from the lower communication terminal 30 to the OLT 20, the higher-level device communication unit 11 uses the data information monitoring unit 16, the data processing, the uplink data received by the lower-level device communication unit 14 from the communication terminal 30. The data is received via the unit 15 and the memory unit 13 and transmitted to the OLT 20.

  The power saving control unit 12 switches the power saving state and the operating state by instructing a specific processing unit in the apparatus to stop or start the operation in a state where the execution condition of the power saving control is satisfied. Further, based on the information of the data processing unit 15 and the data information monitoring unit 16, time information that is information about the sleep time and the active time that are the duration of the power saving state and the operation state that are repeated during the power saving control, Phase information that is information about timing for starting the power saving state or the operating state is determined. The memory unit 13 temporarily stores the data received from the data processing unit 15.

  The lower-level device communication unit 14 includes a PHY circuit (UNI PHY circuit) unit. The PHY circuit unit performs physical layer processing with the communication terminal 30 (see FIG. 1). The PHY circuit unit transmits the downlink data received from the data information monitoring unit 16 to the communication terminal 30. Further, the uplink data received from the communication terminal 30 is output to the data information monitoring unit 16.

  The data processing unit 15 performs processing of data received from the data information monitoring unit 16. After the data processing, the data is stored in the memory unit 13. If a reply is required as a result of the data processing, a reply frame is created and output to the data information monitoring unit 16. Further, the data stored in the memory unit 13 is taken out at a necessary timing, and is framed and output to the data information monitoring unit 16.

  The data information monitoring unit 16 monitors whether or not data has been received from the lower-level device communication unit 14 or the reception function unit 50 and analyzes received data when data is received. After the data analysis, the received data is output to the data processing unit 15. When data (data frame) is received from the data processing unit 15, the destination is confirmed and output to the lower apparatus communication unit 14 or the transmission function unit 18.

  The processing performed by the data information monitoring unit 16 may be performed by the data processing unit 15. That is, the data processing unit 15 and the data information monitoring unit 16 may be combined into one. Further, the optical transmission unit 17, the transmission function unit 18, the optical reception unit 19, and the reception function unit 50 may be combined into one, that is, a transmission / reception integrated configuration.

  FIG. 6 is a diagram illustrating a configuration example of the OLT 20 according to the present embodiment, and illustrates the configuration of the OLT 20 illustrated in FIG. 1 in more detail. As illustrated in FIG. 6, the OLT 20 includes a higher-level device communication unit 21, a memory unit 23, a lower-level device communication unit 24, and a data processing unit 25. The lower apparatus communication unit 24 includes an optical transmission unit 27, a transmission function unit 28, an optical reception unit 29, and a reception function unit 60.

  The host device communication unit 21 includes a PHY circuit (UNI PHY circuit) unit. The PHY circuit unit performs physical layer processing with the communication terminal 40 (see FIG. 1). In the operation of receiving downlink data transmitted from the communication terminal 40, the PHY circuit unit supplies the downlink data received from the communication terminal 40 to the memory unit 23 via the data processing unit 25. The memory unit 23 holds the supplied data, and the downlink data held in the memory unit 23 is read by the data processing unit 25 and transmitted to the ONU 10 (see FIG. 1) via the lower-level device communication unit 24. The On the other hand, in the transmission operation of the uplink data received from the ONU 10 to the communication terminal 40, the PHY circuit unit receives the uplink data received from the ONU 10 by the lower apparatus communication unit 24 and temporarily stored in the memory unit 23 via the data processing unit 25. And transmit to the communication terminal 40.

  The optical receiver 29 of the lower-level device communication unit 24 converts the optical signal received via the transmission medium 1 into an electrical signal, and outputs the converted electrical signal to the reception function unit 60. The transmission function unit 28 controls the light emission timing of the light transmission unit 27 and generates a data string based on the data received from the data processing unit 25. The reception function unit 60 extracts a data string from the data received from the optical reception unit 29 and outputs it to the data processing unit 25. The optical transmission unit 27 of the lower-level device communication unit 24 converts the data received from the transmission function unit 28 into an optical signal and outputs the optical signal to the transmission medium 1.

  The lower-level apparatus communication unit 24 configured as described above performs data transmission / reception processing with the ONU 10 (see FIG. 1). The lower device communication unit 24 supplies the uplink data received from the ONU 10 to the data processing unit 25 in the reception operation of the data transmitted from the ONU 10. The supplied uplink data is transferred to the memory unit 23 and held in the memory unit 23. The uplink data held in the memory unit 23 is read by the data processing unit 25 at a timing to be transmitted to the upper communication terminal 40 (see FIG. 1), and transmitted to the communication terminal 40 via the upper device communication unit 21. Is done. On the other hand, in the transmission operation of the downlink data received from the communication terminal 40 to the ONU 10, the lower apparatus communication unit 24 receives the downlink data received by the upper apparatus communication unit 21 from the communication terminal 40 and held in the memory unit 23 as data. It is received via the processing unit 25 and transmitted to the ONU 10.

  FIG. 7 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.

  First, the communication terminal 30 will be described. The communication terminal 30 includes a memory unit 33, a data processing unit 35, and a higher-level device communication unit 31 (for the sake of convenience, described as “device communication unit” in FIG. 7). The memory unit 33 temporarily stores the supplied data. The higher-level device communication unit 31 includes a PHY circuit unit that performs physical layer processing. The data processing unit 35 outputs the uplink data received from the memory unit 33 to the transmission medium 2 via the higher-level device communication unit 31 and adjusts the output timing of the uplink data. Downstream data received from the higher-level device communication unit 31 is supplied to the memory unit 33.

  The configuration of the communication terminal 40 is that the memory unit 33, the higher-level device communication unit 31, the data processing unit 35, and the transmission medium 2 are replaced with the memory unit 43, the lower-level device communication unit 44, the data processing unit 45, and the transmission medium 3, respectively. Is the same as that of the communication terminal 30.

  Next, basic operations of the ONU 10 and the OLT 20 in the communication system of the present embodiment will be described. The ONU 10 and the OLT 20 synchronize time with each other, perform time division multiplex communication for uplink communication, and perform broadcast communication for downlink communication.

  The OLT 20 sets a time (transmission permission time) that allows the ONU 10 to communicate in the upstream direction so that the data transmitted by the ONU 10 does not collide with upstream data transmitted from other ONUs in the transmission medium 1 during upstream communication. assign. The ONU 10 transmits uplink data at the time assigned by the OLT 20 in uplink communication. In this way, time division multiplex communication is performed in the uplink direction.

  In this way, the OLT 20 performs broadcast transmission toward the ONU 10, and the ONU 10 performs time division multiplexing communication toward the OLT 20 according to the time assigned to itself. The OLT 20 allocates a time during which communication can be performed periodically so that the ONU 10 can request data transmission, and performs a call to notify the time during which communication is possible. The ONU 10 that has received this call responds to the allocated communicable time regardless of the presence or absence of data to be transmitted. Further, when there is no response from the ONU 10 to which a communication-enabled time is assigned for a predetermined time (link timeout time), the OLT 20 considers that there is an abnormality and disconnects the link between the devices. In the GE-PON system, calling is performed by transmitting a GATE signal, and an upstream band is allocated.

  FIG. 8 is a chart showing an example of communication between the ONU 10 and the OLT 20 according to the present embodiment. According to the operation shown in FIG. 8, since the ONU 10 can shift to the power saving mode independently regardless of the presence or absence of the power saving function of the OLT 20, it is possible to expect general-purpose power saving. .

  The operation shown in FIG. 8 will be described. When the link between the ONU 10 and the OLT 20 is established (step S31), the ONU 10 transmits a power saving start request notification to the OLT 20 (step S32). When the OLT 20 has a power saving function, when receiving the power saving start request notification, the OLT 20 transmits a power saving start instruction to the ONU 10 (step S33). Here, the description will be continued assuming that the OLT 20 does not have a power saving function and does not transmit a power saving start instruction in response to a power saving start request notification. After transmitting the power saving start request notification, the ONU 10 monitors whether or not a power saving start instruction, which is a response to the power saving start request notification, has been received for a predetermined time T0 (step S34). Then, the power saving mode to be transferred is determined (step S35). In step S35, when the power saving start instruction is received before the time T0 has elapsed after the power saving start request notification is transmitted, the power saving mode to be shifted is linked to the power saving mode (switching device information). Power saving control operation to be performed). When the time T0 elapses without receiving the power saving start instruction, the power saving mode to be transferred is determined as the power saving mode of the device alone (power saving control operation performed without exchanging device information). Here, the description will be continued assuming that the power saving mode of the device alone is determined.

  When the ONU 10 determines to shift to the power saving mode of the device alone in step S35, the power saving control is started when a certain condition is satisfied. Details of the power saving control corresponding to the power saving mode of the device alone will be described later. However, in the power saving control, the power saving state and the operation state are alternately repeated in a cycle in which the link with the OLT 20 is considered not to be disconnected ( Step S37). As shown in the figure, the sleep time is T2 (the length that does not cause a link break), and the active time is T1. Note that the power saving control start condition is, for example, when no uplink data is received from the communication device 30 for a certain period of time (corresponding to the “power saving judgment time” shown in FIG. 8). If not, etc. Further, when data that the ONU 10 needs to respond to (such as uplink data from the communication terminal 30, data indicating that the OLT 20 holds downlink data) is received, the power saving control is immediately terminated.

  The OLT 20 periodically transmits a call regardless of the state of the ONU 10 (step S36). The ONU 10 returns a response during the T1 period in which it is in the operating state, but does not return a response to the call during the T2 period in which it is in the power saving state.

  FIG. 9 is a flowchart of the operation corresponding to the chart shown in FIG. 8 and shows the operation of each unit in the ONU 10. When the data information monitoring unit 16 detects link establishment after starting the operation (step S131), the data processing unit 15 then transmits a power saving start request notification to the OLT 20 (step S132). Thereafter, the data information monitoring unit 16 monitors whether or not a power saving start instruction has been received over a predetermined time T0 (step S133). When the power saving start instruction is received before the time T0 has elapsed (step S134: Yes), the data information monitoring unit 16 determines that the OLT 20 has a power saving function, and notifies the power saving control unit. 12 is notified. Receiving this notification, the power saving control unit 12 starts an operation according to the power saving control method in which the devices cooperate (the ONU 10 and the OLT 20 cooperate) (step S135).

  On the other hand, if the power saving start instruction is not received within the time T0 after transmitting the power saving start request notification (step S134: No), the data information monitoring unit 16 starts monitoring for the presence or absence of data. It is determined whether or not the condition for shifting to the power mode (the operation in step S37 shown in FIG. 8) is satisfied (step S136). For example, when the uplink data to be transmitted to the OLT 20 does not occur for a certain time (power saving determination time), it is determined that the transition condition is satisfied. If the condition for shifting to the power saving mode is satisfied (step S136: Yes), the data information monitoring unit 16 notifies the power saving control unit 12 to that effect (step S137). Upon receiving this notification, the power saving control unit 12 instructs the optical transmission unit 17 and the transmission function unit 18 of the higher-level device communication unit 11 to stop and restart the operation at a predetermined timing. (Power saving control performed without exchanging device information) is started (step S138). As a result, the power saving state (the state in which the optical transmission unit 17 and the transmission function unit 18 are stopped) and the operation state are periodically repeated. Even after the power saving control is started, the data information monitoring unit 16 continues to monitor whether or not the condition for shifting to the power saving mode is satisfied. When data is received, this is notified to the power saving control unit 12. Upon receiving this notification, the power saving control unit 12 immediately ends the power saving control. At this time, if the optical transmission unit 17 and the transmission function unit 18 are stopped, the power saving control unit 12 instructs the optical transmission unit 17 and the transmission function unit 18 to resume operation. Here, the data information monitoring unit 16 monitors whether or not the power saving start instruction has been received for a certain time T0, and based on the result, the ONU 10 performs the power saving control operation linked between the devices or the ONU alone. Although the power saving operation is executed, the present invention is not limited to this. For example, the ONU 10 may perform a power saving operation alone as a premise, and may perform a power saving operation in cooperation between apparatuses when a power saving parameter is set in parameter negotiation with the OLT 20. In this case, the data information monitoring unit 16 does not perform the monitoring operation.

  In the present embodiment, only the block (the optical transmission unit 17 and the transmission function unit 18) that performs transmission processing of the higher-level device communication unit 11 in the power saving state is stopped, but the block that performs reception processing (optical The receiving unit 19 and the receiving function unit 50) may also be stopped.

  Next, the operation during the power saving mode of the present embodiment will be described. FIG. 10 is a flowchart illustrating an example of the power saving operation (power saving control operation performed without exchanging device information) according to the present embodiment. According to the power saving operation of the present embodiment shown in FIG. 10, the ONU 10 can perform the power saving operation without disconnecting the link. In addition, since each parameter can be dynamically changed according to the situation, more effective power saving can be expected.

  On the other hand, in the power saving operation (power saving control operation performed while exchanging device information) linked between devices, the parameters of the time T11 for entering the operating state and the time T12 for entering the power saving state are shown in FIG. As described above, it is determined at the time of parameter negotiation with the OLT 20 corresponding to the communication device b or by a power saving start instruction transmitted from the OLT 20. The ONU 10 corresponding to the communication device a needs to follow the contents determined by the OLT 20. Although not shown in FIGS. 2 to 4, hold time T <b> 3 from when the generation of transmission waiting data is detected and the power saving mode is ended until the next power saving mode is started (details will be described later). Also, it was necessary to operate at a fixed value determined. Further, in the method in which the ONU 10 performs power saving control without exchanging device information with the OLT 20, it is necessary to maintain a link between devices during the power saving mode. It was necessary to always start the department.

  As shown in FIG. 10, in the ONU 10, the data information monitoring unit 16 monitors the upper and lower data (uplink data and downlink data), and when there is no upper and lower data for a certain time, the power saving control unit 12 sets the optical transmission unit 17. Then, the power saving control of the transmission function unit 18 is started (step S141). The power saving control unit 12 that has started the power saving control performs optical transmission so as to alternately repeat the power saving state of the duration T2 (corresponding to the sleep time) and the operation state of the duration T1 (corresponding to the active time). The unit 17 and the transmission function unit 18 are controlled. In the power saving state, the optical transmission unit 17 and the transmission function unit 18 are stopped, and in the operation state, the optical transmission unit 17 and the transmission function unit 18 are operated.

  The active time T1 is dynamically determined by the following procedure. First, the data information monitoring unit 16 measures a call interval T4 transmitted from the OLT 20 (step S142). The data information monitoring unit 16 notifies the measurement result to the power saving control unit 12 (step S143), and the power saving control unit 12 sets the active time T1 to satisfy T1> T4 based on the notified T4. (Step S144). Further, this operation is periodically repeated to update T1. This makes it possible to reliably return a response to the call from the OLT 20 in the operating state.

  The sleep time T2 is dynamically determined according to the following procedure. First, the data information monitoring unit 16 monitors time T5 when the data processing unit 15 returns a response (response to the call) to the OLT 20 during the operation state, and notifies the power saving control unit 12 (step S145). Next, the power saving control unit 12 considers the call interval T4 notified in step S143 and the rise time T6 of the power saving control target portion (the optical transmission unit 17, the transmission function unit 18) (FIG. 11). Reference), the start time T8 and the sleep time T2 of the power saving state are determined so as to satisfy the link timeout time T7> {(T8−T5) + T2 + T6 + T4} (step S146). That is, as shown also in FIG. 11, the transmission interval of the response to the call from the OLT 20 is shorter than the link timeout time T7 (the next response is transmitted before the time T7 has elapsed since the response was transmitted. Thus, the start time T8 and the sleep time T2 of the power saving state are determined. In this embodiment, only the transmission operation is stopped in the power saving state. However, when the reception operation is also stopped (the optical reception unit 19 and the reception function unit 50 are also stopped), a response is made. Since it is necessary to know the time during which the call can be received and communicated (the period during which transmission is permitted) in order to send the call, it is acquired during the operation state so that it can return to the operation state when the call can be received. T8 and T2 are determined from T4 and T5. Further, these operations in steps S142 to S146 are periodically repeated to update T8 and T2.

  With the above operation, the power saving control unit 12 can determine the maximum value of the sleep time T2 and the minimum value of the active time T1, and can perform power saving control that maximizes the power saving effect. . In addition, by periodically repeating the determination (updating) of the sleep time T2 and the active time T1, it is possible to absorb time variation of each parameter and realize efficient power saving. The ONU 10 does not necessarily have to repeat the power saving state at the maximum sleep time T2 and the operation state at the minimum active time T1, but a value smaller than the maximum value of the sleep time T2 and the minimum value of the active time T1. The power saving operation may be performed with a larger value.

  FIG. 12 is a flowchart illustrating an example of the power saving mode release operation (power saving control end operation) according to the present embodiment. According to the power saving mode canceling operation of the present embodiment shown in FIG. 12, even after once canceling the power saving mode, the ONU 10 can quickly re-enter the power saving mode if the condition is satisfied. Therefore, more efficient power saving can be expected.

  The data information monitoring unit 16 sets the power saving mode in the power saving mode in which the power saving control unit 12 performs power saving control (power saving control performed without exchanging device information) of the optical transmission unit 17 and the transmission function unit 18. Monitor top and bottom data to determine if it needs to be released. As a result of monitoring, when the occurrence of uplink data or downlink data is detected, it is determined that it is necessary to cancel the power saving mode, and the cancellation of the power saving mode is notified to the power saving control unit 12 (step S151). Further, the data information monitoring unit 16 notifies the data processing unit 15 of a data processing command (step S152). The power saving control unit 12 immediately ends the power saving control after receiving the notification of canceling the power saving mode (step S153). That is, if the optical transmission unit 17 and the transmission function unit 18 (see FIG. 5) are stopped, they are returned to the operating state. The data processing unit 15 starts data processing (step S154). The data processing unit 15 monitors whether or not the data processing is completed (step S155). When the data processing completion is detected (step S155: Yes), the data processing unit 15 notifies the data information monitoring unit 16 (step S156). Upon receiving the data processing completion notification, the data information monitoring unit 16 confirms again whether the conditions for shifting to the power saving mode are satisfied (step S157). This step S157 is the same process as step S136 of FIG. 9 described above. If the condition for shifting to the power saving mode is satisfied (step S157: Yes), the data information monitoring unit 16 notifies the power saving control unit 12 to that effect (step S158). Upon receiving this notification, the power saving control unit 12 starts power saving control that instructs the optical transmission unit 17 and the transmission function unit 18 of the higher-level device communication unit 11 to stop and restart the operation at a predetermined timing (step). S159). These steps S158 and S159 are the same processing as steps S137 and S138 of FIG. 9 described above. In the above description, the call interval T4 transmitted from the OLT 20 has been described as being constant. However, for example, when the call interval T4 is changed due to a change in the number of ONUs 10 connected to the OLT 20, a change in subscribed service, or the like. After measuring the call interval T4 after the change, the power saving state start time T8 and sleep time T2 may be determined. Even if the data information monitoring unit 16 detects uplink data or downlink data in the power saving mode, the power saving control unit 12 does not have to immediately cancel the power saving mode. Alternatively, if the data rate of downlink data is low, the power saving mode may be maintained as it is. In that case, uplink data or downlink data is accumulated in the memory unit 13 and processing such as transmission is performed after the power saving mode is canceled.

  In the power saving control linked between the apparatuses, the hold time T3 corresponding to the processing time from step S155 to step S159 in FIG. 12 is determined by the parameter negotiation in step S1 shown in FIG. 2, and a fixed value is set. . For this reason, when data processing is delayed, power saving control is started before the completion of data processing, and data loss may occur. On the other hand, according to the control shown in FIG. 12, since the transition condition to the power saving mode is confirmed after confirming that the data processing is completed, the hold time T3 is set as shown in FIG. It can be set dynamically according to the progress of data processing.

  As described above, in this embodiment, the ONU determines whether or not the OLT has the power saving function, and if the ONU has the power saving function, the power saving control (ONU and OLT exchange device information) linked between the devices. Control to shift to the power saving state), and if it does not have the power saving function, whether or not to shift to the power saving mode independently based on the monitoring result of the uplink data and downlink data It was decided to judge. Thereby, even when the ONU is connected to an OLT that does not support power saving control linked between apparatuses, the ONU can shift to the power saving mode and reduce power consumption. In addition, after the transition to the power saving mode, the active time T1 and the sleep time T2 are dynamically changed according to the data processing status within a range in which the link between the ONU and the OLT is not broken. Furthermore, after returning from the power saving state to the operating state due to the occurrence of data, the transition to the power saving state is not performed until the data processing is completed, and the state immediately shifts to the power saving state after the data processing is completed. As described above, the power saving of the ONU can be performed for a general purpose, and the power saving state can be ensured for a long time, and the power saving can be efficiently achieved. In the above description, the ONU has been described as dynamically determining the active time T1 and the sleep time T2. However, the present invention is not necessarily limited to this, and the ONU (the power saving control unit 12 or another storage device included in the ONU is not necessarily limited thereto. Etc.) may be stored in advance as fixed values. The fixed value in that case may be set as a value that does not exceed the link timeout time.

Embodiment 2. FIG.
FIG. 14 is a diagram illustrating a configuration example of an ONU (referred to as ONU 10a) according to the second embodiment. The configuration of the communication system of the present embodiment is the same as that of the first embodiment except that the ONU 10 shown in FIG. 1 is replaced with the ONU 10a. 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. 14, the ONU 10a of the present embodiment is obtained by replacing the power saving control unit 12 of the ONU 10 (see FIG. 5) of the first embodiment with a power saving control unit 12a.

  In the ONU 10a of the present embodiment, the memory unit 13 is added as a target for power saving control. That is, the power saving control unit 12a controls the operation stop and operation start of the optical transmission unit 17, the transmission function unit 18, and the memory unit 13 during the power saving mode.

  The operation according to each function of this embodiment will be described below. The operation from when the data information monitoring unit 16 determines the link establishment until the determination of the condition for shifting to the power saving mode is the same as that of the first embodiment (see FIGS. 8 and 9). In the present embodiment, when the condition for shifting to the power saving mode is satisfied, the power saving control unit 12a controls the optical transmission unit 17, the transmission function unit 18, and the memory unit 13 to periodically change the power saving state and the operation state. Repeat. The data information monitoring unit 16 monitors whether or not the condition for shifting to the power saving mode is satisfied, and if the state that does not satisfy the condition for shifting to the power saving mode is detected in the power saving mode, the data information monitoring unit 16 saves the fact. The power control unit 12a is notified, and the power saving control unit 12a immediately ends the power saving control.

  The operation of the ONU 10a during the power saving mode is the same as that of the ONU 10 of the first embodiment. However, when the data information monitoring unit 16 detects the upper and lower data, the memory unit 13 must be kept in an operating state while the data passes through the data processing unit 15. Alternatively, the data processing unit 15 needs to store data until the memory unit 13 is in an operating state. Before starting the data processing, the data processing unit 15 checks whether or not the memory unit 13 is in an operating state by reading specific data from the memory unit 13 or the like. Instead of confirming the state of the memory unit 13 by a data read operation, it may be confirmed by a write operation (data write / response detection).

  As described above, the ONU of the present embodiment is also subject to power saving control for the memory unit 13 in addition to the optical transmission unit 17 and the transmission function unit 18. Thereby, power consumption can be further reduced as compared with the first embodiment.

Embodiment 3 FIG.
The configuration of the communication system and the configuration of each device in the present embodiment are the same as those in the first embodiment (see FIGS. 1 and 5).

  FIG. 15 is a chart diagram illustrating an example of communication between the ONU and the OLT in the communication system according to the third embodiment. FIG. 16 is a flowchart of the operation corresponding to the chart shown in FIG. In FIG. 15, the same step numbers are assigned to portions common to the chart (FIG. 8) illustrating an example of ONU-OLT communication in the first embodiment. In this embodiment, parts different from those in Embodiment 1 will be described.

  In the communication system according to the present embodiment, after the ONU 10 and the OLT 20 establish a link in step S31, the OLT 20 transmits a parameter negotiation notification in order to collect parameter information necessary for power saving control from the ONU 10. In the parameter negotiation notification, the ONU 10 is inquired about operable parameters (parameters that can be used in power saving control). If the OLT 20 does not have a power saving function, the OLT 20 does not transmit a parameter negotiation notification after the link is established.

  On the other hand, unlike the first and second embodiments, the ONU 10 according to the present embodiment does not transmit a power saving start request notification to the OLT 20 after the link is established in step S31. After the link is established, the ONU 10 monitors the parameter negotiation notification transmitted from the OLT 20 for a predetermined time T0, thereby determining whether or not the OLT 20 has the power saving function and determining the power saving mode to be shifted (step S41). , S35). Specifically, when the parameter negotiation notification is received before the time T0 elapses after the link is established, the ONU 10 performs a power saving control method (a power saving control method that requires device information exchange). ) To perform the operation according to. In contrast, when T0 time has elapsed without receiving the parameter negotiation notification after the link is established, the power saving control in step S37 (power saving control without exchanging device information described in the first embodiment). Decide to do.

  The flowchart in FIG. 16 corresponding to the above operation is obtained by replacing steps S132 to S134 in the flowchart shown in FIG. 9 with steps S141 and S142.

  In the ONU 10, after the link is established, the data information monitoring unit 16 waits for a predetermined time T0 until a parameter negotiation notification is transmitted (step S142). When the parameter negotiation notification is received before the time T0 elapses (step S142: Yes), it is determined that the OLT 20 has the power saving function, and the fact is notified to the power saving control unit 12 (step S135). Transition). On the other hand, when the parameter negotiation notification is not received within the time T0 (step S142: No), it is determined that the OLT 20 does not have the power saving function, and it is determined to execute the power saving control without exchanging the device information. Then, the process proceeds to step S136.

  As described above, the ONU according to the present embodiment determines whether or not the OLT has a power saving function based on whether or not a parameter negotiation notification is transmitted from the OLT. Therefore, when the ONU is connected to an OLT that does not have a power saving function, the same effect as in the first embodiment can be obtained even if the data processing unit 15 does not have a power saving start request notification function. Can be obtained.

Embodiment 4 FIG.
The configuration of the communication system and the configuration of each device in the present embodiment are the same as those in the first embodiment (see FIGS. 1 and 5).

  FIG. 17 is a chart showing an example of ONU-OLT communication in the communication system according to the fourth embodiment. FIG. 18 is a flowchart of the operation corresponding to the chart shown in FIG. Note that, in FIG. 17, the same step numbers are assigned to portions common to the chart (FIG. 8) illustrating an example of ONU-OLT communication in the first embodiment. In this embodiment, parts different from those in Embodiment 1 will be described.

  After the ONU 10 and the OLT 20 establish a link in step S31, the OLT 20 transmits a parameter negotiation notification in order to collect parameter information necessary for power saving control from the ONU 10 (step S51). In the parameter negotiation notification, the ONU 10 is inquired about operable parameters (parameters that can be used in power saving control). If the OLT 20 does not have a power saving function, the OLT 20 does not transmit a parameter negotiation notification.

  Upon receiving the parameter negotiation notification, the ONU 10 transmits a parameter negotiation response to notify the OLT 20 of operable parameters (step S52). When receiving the parameter negotiation response, the OLT 20 determines a parameter to be used in power saving control based on the notified parameter, and notifies the determined parameter to the ONU 10 as a parameter negotiation result (step S53). In step S53, the OLT 20 determines an active time (referred to as T01), sleep time (referred to as T02), and hold time in the power saving mode, and notifies the ONU 10 of them.

  The ONU 10 determines the power saving mode to be shifted based on the parameter negotiation result received from the OLT 20 (step S35). Specifically, the power consumption when power saving control (power saving control linked between devices) is performed according to the times T01 and T02 notified by the parameter negotiation result, and the power saving control (implementation without exchanging device information). The power consumption when the power saving control according to the times T1 and T2 described in the first embodiment is performed is compared, and it is determined to execute the power saving control with the larger power consumption reduction effect. In this case, even when the OLT 20 has a power saving function, the ONU 10 can select the power saving control that provides a high power saving effect.

  The flowchart in FIG. 18 corresponding to the above operation is obtained by replacing steps S132 to S134 in the flowchart shown in FIG. 9 with steps S151 to S154.

  In the ONU 10, after receiving the parameter negotiation notification after the link is established, the data information monitoring unit 16 analyzes the contents (step S151). Next, the data processing unit 15 generates a parameter negotiation response having contents corresponding to the analysis result, and transmits it to the OLT 20 (step S152). Thereafter, the data information monitoring unit 16 monitors whether or not the parameter negotiation result has been notified (step S153). When the data information monitoring unit 16 detects the notification (step S153: Yes), the data information monitoring unit 16 is notified. Based on the determined parameters, the power saving mode to be transferred is determined (step S154). In step S154, the ratio (= T02 / T01) between the active time T01 and the sleep time T02, which is the notified parameter, is calculated, and the ratio between the active time T1 and the sleep time T2 in the power saving control without exchanging device information. (T2 / T1) is calculated, and when the calculated ratio relationship is “(T02 / T01) <(T2 / T1)” (step S154: Yes), it is determined to perform power saving control without exchanging device information. Then, the process proceeds to step S136. When the relationship of the calculated ratio is “(T02 / T01) ≧ (T2 / T1)” (step S154: No), it is decided to perform power saving control in cooperation between the devices, and this is saved. The control unit 12 is notified (step S135). Note that the determination formula used in step S154 is not limited to the above. If it is possible to determine whether more power reduction can be achieved when power saving control (power saving control linked between devices) performed while exchanging device information or power saving control without exchanging device information is applied Any discriminant may be used.

  As described above, in this embodiment, even when power saving control performed while exchanging device information can be selected, it is more effective to select power saving control that does not exchange device information. If it can be achieved, power saving control without exchanging device information is executed. Thereby, the power consumption reduction effect can be enhanced.

  As described above, the ONU (slave station device) according to the present invention is useful for a communication system for achieving power saving.

  1, 2, 3 Transmission medium, 10 Slave unit (ONU), 11, 21, 31 Host device communication unit, 12 Power saving control unit, 13, 23, 33, 43 Memory unit, 14, 24, 44 Lower device communication 15, 25, 35, 45 Data processing unit, 16 Data information monitoring unit, 17, 27 Optical transmission unit, 18, 28 Transmission function unit, 19, 29 Optical reception unit, 20 Master station device (OLT), 30, 40 Communication terminal, 50, 60 Reception function unit.

Claims (9)

A slave station device that forms a communication system with the master station device,
A communication processing unit that transmits and receives control signals and data signals to and from the master station device;
Based on the communication content after the link with the parent station device is established, it is determined whether the parent station device is compatible with power saving control performed while exchanging control information between the devices, and based on the determination result The first power saving mode for alternately switching between the power saving state and the operation state at the cycle determined by the master station device, or the cycle determined based on the reception result of the control signal transmitted from the master station device or A power saving mode selection unit that selects a second power saving mode that alternately switches between a power saving state and an operation state at a preset cycle;
A power saving control unit that executes power saving control according to the power saving mode selected by the power saving mode selection unit for a transmission function or a reception function of the communication processing unit, or a transmission / reception function;
A slave station device comprising: The power saving mode selection unit includes:
The slave station apparatus according to claim 1, wherein the first power saving mode is selected when the master station apparatus supports the power saving control. The power saving mode selection unit includes:
When the master station determination unit determines that the master station device is compatible with the power saving mode,
2. The slave station device according to claim 1, wherein a power saving mode that provides a higher power saving effect is selected from the first power saving mode and the second power saving mode. When the power saving mode selection unit selects the second power saving mode,
The power saving mode control unit includes:
Based on the notification period of the communication permission time notified from the master station device and the link timeout time, the duration of the power saving state and the duration of the operation state in the second power saving mode are determined, and each determined The slave station apparatus according to claim 1, 2 or 3, wherein control according to a duration is performed on the communication processing unit. The power saving control unit
In addition to the communication processing unit, a memory unit that temporarily holds data to be transmitted to the master station device and data received from the master station device is in accordance with the power saving mode selected by the power saving mode selection unit. The slave station device according to any one of claims 1 to 4, wherein the slave station device is a control target. The power saving mode selection unit includes:
The control signal transmitted from the master station device within the predetermined time is monitored, and when the control signal used in the power saving control is transmitted from the master station device, the master station device The slave station apparatus according to claim 1, wherein the slave station apparatus determines that the control is supported. The power saving mode selection unit includes:
The base station apparatus determines that the base station apparatus is compatible with the power saving control when an instruction to start an operation according to the power saving control is transmitted from the base station apparatus. Slave station device. The power saving mode selection unit includes:
When the inquiry of the parameter information used in the operation according to the power saving control is transmitted from the parent station device, it is determined that the parent station device is compatible with the power saving control. Item 7. The slave station device according to item 6. A power saving control method executed by a slave station device constituting a communication system together with a master station device,
A master station determination step for determining whether or not the master station apparatus is compatible with power saving control performed while exchanging control information between the apparatuses based on communication contents after the link with the master station apparatus is established. ,
A first power saving mode in which a power saving state and an operation state are alternately switched in a cycle determined by the parent station device based on a determination result in the parent station determination step, or a control signal transmitted from the parent station device A power saving mode selection step of selecting a second power saving mode that alternately switches between a power saving state and an operating state at a cycle determined based on the reception result of
The power saving control according to the power saving mode selected by the power saving mode selection unit is used as a transmission function or a reception function or a transmission / reception function of a communication processing unit that transmits / receives a control signal and a data signal to / from the master station device. Power-saving control steps to be executed
A power saving control method comprising:

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