JP2013081065A - Power saving control method, station side device, and communication system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power saving control method, a station side device, and a communication system that can adequately perform power saving of the station side device.SOLUTION: A power saving control method in a communication system, which comprises one or multiple user-side devices 102, and a station side device 101 for transmitting and receiving a communication signal with each user-side device 102 via a common communication line, and in which a communication signal from each user-side device 102 to the station side device 101 is time division multiplexed, includes the steps of: obtaining traffic information indicating the traffic amount of a communication signal from each user-side device 102 to the station side device 101; and determining whether or not it is possible for the station side device 101 to transit to a sleep state to stop reception operation of the communication signal transmitted from each user-side device 102 on the basis of the obtained traffic information.

Description

  The present invention relates to a power saving control method, a station-side device, and a communication system, and more particularly, to a power saving control method, a station-side device, and a communication system for reducing power consumption of a station-side device.

  In recent years, the Internet has become widespread, and users can access various information on sites operated in various parts of the world and obtain the information. Along with this, devices capable of broadband access such as ADSL (Asymmetric Digital Subscriber Line) and FTTH (Fiber To The Home) are rapidly spreading.

  In IEEE Std 802.3ah (registered trademark) -2004 (non-patent document 1), a plurality of home side devices (ONU: Optical Network Unit) share an optical communication line, and a station side device (OLT: Optical Line Terminal). One method of a passive optical network (PON), which is a medium-sharing communication that performs data transmission with the network, is disclosed. That is, EPON (Ethernet (registered trademark) PON) in which all information is communicated in the form of an Ethernet (registered trademark) frame, including user information passing through the PON and control information for managing and operating the PON, and EPON An access control protocol (MPCP (Multi-Point Control Protocol)) and an OAM (Operations Administration and Maintenance) protocol are defined. By exchanging MPCP frames between the station side device and the home side device, the home side device joins and leaves, and uplink access multiplexing control is performed. Non-Patent Document 1 describes a registration method for a new home device, a report indicating a bandwidth allocation request, and a gate indicating a transmission instruction using an MPCP message.

  In addition, IEEE 802.3av (registered trademark) -2009 is standardized as the next generation technology of GE-PON (Giga Bit Ethernet (registered trademark) Passive Optical Network), which is an EPON realizing a communication speed of 1 gigabit / second. Even in the 10 G-EPON, that is, the EPON corresponding to a communication speed of 10 gigabits / second, the access control protocol is premised on MPCP.

  As an example of a method for achieving power saving in the PON system, for example, Japanese Unexamined Patent Application Publication No. 2010-114830 (Patent Document 1) discloses the following configuration. That is, in a PON system that performs optical communication between a station-side device and a plurality of home-side devices via an optical branching unit, the transmitting unit of the station-side device accumulates user frames that are sequentially transmitted to each home-side device. And a power saving mode control unit. The power saving mode control unit transmits an uplink bandwidth allocation control frame to the home side device to the home side device in which the user frame to be transmitted in the downlink buffer unit is empty, and then the other home side device. A power saving mode setting frame describing a power saving mode time set to a time shorter than one round time until the uplink side bandwidth allocation control frame is transmitted to the home side apparatus is transmitted. The PON receiving unit of the home side device has a frame analysis unit that analyzes a frame addressed to the local station received from the station side device. When the frame analysis unit receives the power saving mode setting frame, the frame analysis unit sets the PON receiving unit to the power saving mode for the power saving mode time described in the power saving mode setting frame.

IEEE Std 802.3ah (registered trademark) -2004

JP 2010-114830 A

  In the PON system described in Patent Literature 1, it is possible to save power in the home device. However, since it is necessary for the station-side device to receive an upstream frame from each home-side device, it is difficult to save power as in the home-side device.

  The present invention has been made to solve the above-described problems, and an object thereof is to provide a power-saving control method, a station-side apparatus, and a communication system that can appropriately achieve power-saving of a station-side apparatus. That is.

  In order to solve the above problems, a power saving control method according to an aspect of the present invention is a method for transmitting and receiving a communication signal via one or a plurality of home-side devices and a common communication line with each of the home-side devices. A power-saving control method in a communication system in which the communication signals from each home device to the station device are time-division multiplexed, each from the home device to the station device Acquiring traffic information indicating the traffic volume of the communication signal, and, based on the acquired traffic information, transition to a sleep state in which the reception operation of the communication signal transmitted from each home device is stopped. Determining whether or not it is possible in the station side device.

  With such a configuration, it is possible to appropriately determine the transition to the sleep state based on the traffic volume, and reduce the power consumption of the station side device by stopping the operation of the communication signal receiving circuit in the station side device. Can do. Therefore, power saving of the station side device can be appropriately achieved.

  Preferably, when the power saving control method further determines that the station side apparatus can transition to the sleep state when it is determined that the station side apparatus can transition to the sleep state, Controlling the transmission of the communication signal to the network.

  With such a configuration, it is possible to lengthen the period in which there is no uplink traffic from each home-side device, so that the power saving effect in the station-side device can be further enhanced.

  More preferably, in the step of controlling transmission of the communication signal, the home device is controlled so that the communication signal is transmitted from the home device to the station device within a predetermined interval. .

  With such a configuration, the timing at which communication signals arrive from each home-side device can be concentrated, and the period during which the communication signal does not arrive can be made as long as possible. Therefore, the station-side device ensures a sufficient period as a sleep period. This can increase the power saving effect.

  More preferably, in the step of controlling transmission of the communication signal, the allocation of the band in the communication line to each home device is stopped, and the power saving control method further includes: A step of entering the sleep state during a period in which the communication signal does not arrive from the home side devices to the station side device due to the stop of allocation.

  With such a configuration, it is possible to reliably provide a period in which no communication signal arrives from each home-side device, so that the station-side device can reliably ensure the sleep period and can improve the power saving effect. .

  Preferably, the station side device has an allocation period including a reception period of a bandwidth allocation request in the communication line from each home device and a scheduled reception period of the communication signal from each home device. Repetitively, the power saving control method further includes a step of transitioning to the sleep state after the station side apparatus completes the reception of the scheduled communication signal in the reception period of the communication signal.

  After receiving all communication signals from each home-side device in a certain allocation cycle, no communication signal arrives from each home-side device until the next allocation cycle starts. With the configuration in which this period is set as the sleep period, the station-side apparatus can secure a sufficient period as the sleep period in the operation of repeating the normal allocation cycle, so that the power saving effect can be enhanced.

  In order to solve the above problems, a station apparatus according to an aspect of the present invention is a station for transmitting and receiving communication signals via one or a plurality of home apparatuses and a communication line common to each of the home apparatuses. A communication device in which the communication signal from each home device to the station device is time-division multiplexed, wherein each home device is connected to the station device. A traffic information acquisition unit for acquiring traffic information indicating the traffic volume of the communication signal, and the communication signal transmitted from each home-side device based on the traffic information acquired by the traffic information acquisition unit A sleep control unit for determining whether or not the station side device can transition to the sleep state in which the reception operation is stopped.

  With such a configuration, it is possible to appropriately determine the transition to the sleep state based on the traffic volume, and reduce the power consumption of the station side device by stopping the operation of the communication signal receiving circuit in the station side device. Can do. Therefore, power saving of the station side device can be appropriately achieved.

  In order to solve the above-described problems, a communication system according to an aspect of the present invention includes a station side for transmitting and receiving communication signals via one or a plurality of home-side devices and a common communication line with each of the home-side devices. A communication system in which the communication signals from each home side device to the station side device are time-division multiplexed, and the traffic volume of the communication signal from each home side device to the station side device A traffic information acquisition unit for acquiring traffic information indicating a sleep, and a sleep for stopping the reception operation of the communication signal transmitted from each home-side device based on the traffic information acquired by the traffic information acquisition unit A sleep control unit for determining whether or not transition to the state is possible in the station side device.

  With such a configuration, it is possible to appropriately determine the transition to the sleep state based on the traffic volume, and reduce the power consumption of the station side device by stopping the operation of the communication signal receiving circuit in the station side device. Can do. Therefore, power saving of the station side device can be appropriately achieved.

  ADVANTAGE OF THE INVENTION According to this invention, the power saving of a station side apparatus can be aimed at appropriately.

It is a figure which shows the structure of the PON system which concerns on embodiment of this invention. It is a block diagram which shows the structure of the station side apparatus which concerns on embodiment of this invention. It is a figure which shows the structure of a part of upstream frame receiving part in the station side apparatus which concerns on embodiment of this invention. It is the flowchart which defined the operation | movement procedure at the time of the station side apparatus in the PON system which concerns on embodiment of this invention performing a power saving process. It is the flowchart which defined the operation | movement procedure at the time of the DBA process part in the station side apparatus which concerns on embodiment of this invention performing a power saving process. It is a figure which shows an example of the method in which the DBA process part in the station | side apparatus which concerns on embodiment of this invention judges whether the transition to a sleep state is possible. It is a figure which shows an example of the flow of the data between the station side apparatus in a PON system which concerns on embodiment of this invention, and a home side apparatus.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals and description thereof will not be repeated.

  FIG. 1 is a diagram showing a configuration of a PON system according to an embodiment of the present invention.

  Referring to FIG. 1, a PON system 201 is, for example, a 10G-EPON, and includes ONUs 102A, 102B, 102C, and 102D, a station-side device 101, and splitters SP1 and SP2. The ONUs 102A, 102B, and 102C and the station apparatus 101 are connected via the splitters SP1 and SP2 and the optical fiber OPTF, and transmit / receive optical signals to / from each other. The ONU 102D and the station apparatus 101 are connected via the splitter SP2 and the optical fiber OPTF, and transmit / receive optical signals to / from each other. In the PON system 201, optical signals from the ONUs 102A, 102B, 102C, and 102D to the station side apparatus 101 are time-division multiplexed.

  Here, the direction from the ONU to the upper network is referred to as an upstream direction, and the direction from the upper network to the ONU is referred to as a downstream direction.

  FIG. 2 is a block diagram showing a configuration of the station side apparatus according to the embodiment of the present invention.

  Referring to FIG. 2, the station apparatus 101 includes a PON transceiver 11, an upstream reception processing unit 12, an upstream buffer memory 13, an upstream transmission processing unit 14, an SNI transceiver 15, a downstream reception processing unit 16, A downlink buffer memory 17, a downlink transmission processing unit 18, a DBA (Dynamic Bandwidth Allocation) processing unit (traffic information acquisition unit and sleep control unit) 19, a control unit 20, and a transceiver reception control unit 21 are provided. The PON transceiver 11 includes a reception unit 31 and a transmission unit 32. The SNI transceiver 15 includes a transmission unit 33 and a reception unit 34.

  In the station side device 101, the PON transceiver 11 is connected to an optical fiber OPTF that is a PON line as a master station side starting point of the PON line. The receiving unit 31 in the PON transceiver 11 receives an upstream optical signal of a specific wavelength, for example, a 1310 nm band from the optical fiber OPTF and converts it into an electrical signal so that bidirectional communication with each ONU 102 can be performed via the optical fiber OPTF. And output to the uplink reception processing unit 12. In addition, the transmission unit 32 in the PON transceiver 11 converts the electrical signal received from the downstream transmission processing unit 18 into a downstream optical signal having another wavelength and outputs the downstream optical signal to the optical fiber OPTF. For example, the PON transceiver 11 converts an electrical signal of 10 Gbps received from the downstream transmission processing unit 18 into a downstream optical signal in the 1570 nm band and transmits it to each ONU 102.

  The upstream reception processing unit 12 reconstructs a frame from the electrical signal received from the PON transceiver 11 and distributes the frame to the DBA processing unit 19, the control unit 20, or the upstream buffer memory 13 according to the type of the frame. Specifically, the data frame is output to the upstream buffer memory 13 and the control frame is output to the DBA processing unit 19 and the control unit 20.

  The upstream buffer memory 13 stores the data frame received from the upstream reception processing unit 12.

  The upstream transmission processing unit 14 extracts the data frame from the upstream buffer memory 13, performs predetermined signal processing, and outputs the processed frame to the SNI transceiver 15.

  The transmission unit 33 in the SNI transceiver 15 transmits the frame received from the uplink transmission processing unit 14 to the upper network.

  The receiving unit 34 in the SNI transceiver 15 outputs the frame received from the upper network to the downlink reception processing unit 16.

  The downlink reception processing unit 16 performs predetermined signal processing on the frame received from the SNI transceiver 15 and outputs the processed frame to the downlink buffer memory 17 as a data frame.

  The DBA processing unit 19 and the control unit 20 generate control frames indicating various types of control information and output them to the downlink transmission processing unit 18.

  The downlink transmission processing unit 18 takes out the data frame from the downlink buffer memory 17, converts it into an electrical signal of the physical layer, and outputs it to the PON transceiver 11. Further, the downlink transmission processing unit 18 converts the control frame received from the DBA processing unit 19 and the control unit 20 into an electrical signal of the physical layer and outputs the electrical signal to the PON transceiver 11.

  The DBA processing unit 19 and the control unit 20 generate control frames such as MPCP frames and OAM frames for operating and managing the PON line and the ONU 102, and transmit them to the ONU 102 via the downlink transmission processing unit 18. Further, the DBA processing unit 19 and the control unit 20 receive control frames such as MPCP frames and OAM frames transmitted from the ONU 102 via the uplink reception processing unit 12 and perform corresponding processes.

  Specifically, the DBA processing unit 19 and the control unit 20 perform station side processing related to control and management of the PON line such as MPCP and OAM. In other words, by exchanging MPCP messages and OAM messages with each ONU connected to the PON line, including ONU registration, leaving, and uplink access control including bandwidth allocation, downlink access control, and sleep instruction to the ONU Manages ONU operations.

  For example, the DBA processing unit 19 allocates the upstream bandwidth in the PON line to each ONU 102 based on the upstream bandwidth allocation request in the PON line received from each ONU 102. Specifically, the DBA processing unit 19 allocates a bandwidth in the PON line to the ONU 102 based on a report frame indicating a bandwidth allocation request in the PON line received from the ONU 102, that is, sends a gate frame describing a grant to the ONU 102. .

  The DBA processing unit 19 repeats an allocation cycle, that is, a DBA cycle including a reception period of a bandwidth allocation request on the PON line from each ONU 102 and a scheduled uplink frame reception period from each ONU 102. Here, for example, the DBA processing unit 19 calculates the bandwidth allocation amount in the scheduled reception period of the upstream frame from each ONU 102.

  The control unit 20 controls the transceiver reception control unit 21 based on the information received from the DBA processing unit 19 to output a control signal indicating a sleep command to the reception unit 31 and the upstream reception processing unit 12 in the PON transceiver 11. To do. Further, the control unit 20 controls the transceiver reception control unit 21 based on the information received from the DBA processing unit 19, thereby receiving a control signal indicating a wake-up command in the reception unit 31 and the upstream reception processing unit 12 in the PON transceiver 11. Output to.

  FIG. 3 is a diagram showing a partial configuration of an uplink frame receiving unit in the station side apparatus according to the embodiment of the present invention.

  With reference to FIG. 3, the uplink reception processing unit 12 includes a CDR (Clock and Data Recovery) 41, a deserializer 42, and a MAC processing unit 43.

  In the upstream direction, the CDR 41 performs reshaping of the electrical signal received from the PON transceiver 11, extracts timing from the electrical signal, and performs retiming of the electrical signal based on the extracted timing. Establish synchronization.

  The deserializer 42 converts the serial electrical signal received from the CDR 41 into a parallel electrical signal and outputs the parallel electrical signal to the MAC processing unit 43.

  The MAC processing unit 43 reconfigures a frame by performing predetermined processing in a MAC (Media Access Control) layer on the electrical signal received from the deserializer 42.

  In the downstream direction, the MAC processing unit 43 converts the frame received from the downstream transmission processing unit 18 into a parallel physical layer electrical signal by performing predetermined processing in the MAC layer.

  The serializer 44 converts the parallel electrical signal received from the MAC processing unit 43 into a serial electrical signal and outputs the serial electrical signal to the PON transceiver 11.

  The receiving unit 31 in the PON transceiver 11 stops its operation when receiving a control signal indicating a sleep command from the transceiver receiving control unit 21. The receiving unit 31 in the PON transceiver 11 resumes operation when receiving a control signal indicating a wake-up command from the transceiver reception control unit 21. The CDR 41 and the deserializer 42 are also configured to stop operation when receiving a control signal indicating a sleep command from the transceiver reception control unit 21 and resume operation when receiving a control signal indicating a wake-up command from the transceiver reception control unit 21. It may be.

[Operation]
Next, an operation when the PON system according to the embodiment of the present invention performs power saving control will be described with reference to the drawings.

  The DBA processing unit 19 acquires traffic information indicating the traffic amount of the upstream frame from each ONU 102 to the station side device 101.

  Based on the acquired traffic information, the DBA processing unit 19 determines whether or not the station side device 101 can transition to the sleep state in which the reception operation of the uplink frame transmitted from each ONU 102 is stopped.

  When the DBA processing unit 19 determines that it is possible to transition to the sleep state, the DBA processing unit 19 controls transmission of an upstream frame from each ONU 102 to the station side device 101 so that the station side device 101 can transition to the sleep state. .

  FIG. 4 is a flowchart defining an operation procedure when the station side apparatus in the PON system according to the embodiment of the present invention performs the power saving process.

  Referring to FIG. 4, first, in a certain DBA cycle, station apparatus 101 receives report frame 1 from each ONU 102 (step S1).

  Next, the station apparatus 101 calculates the total amount of bandwidth requests from each ONU 102 based on the report frame 1 received from each ONU 102 (step S2), and determines whether or not it can transition to the sleep state. (Step S3).

  For example, since the total amount of bandwidth requests from each ONU 102 is equal to or greater than a predetermined value, the station-side apparatus 101 determines that it cannot transition to the sleep state in the next DBA cycle (NO in step S3).

  Then, since the station side device 101 cannot transition to the sleep state in the next DBA cycle, the station side device 101 calculates the transmission timing and the transmittable time of each ONU 102 as usual (step S13).

  Next, the station apparatus 101 transmits a gate frame indicating the calculation result to each ONU 102 (step S14).

  In parallel with the above operations, the station apparatus 101 receives the upstream frame transmitted from each ONU 102. This upstream frame is a frame transmitted by each ONU 102 according to the grant indicated by the gate frame transmitted by the station apparatus 101 in the previous DBA cycle. The station apparatus 101 receives the report frame from each ONU 202 again in the next DBA cycle (step S1).

  On the other hand, when the station side apparatus 101 determines that the transition to its own sleep state is possible in the next DBA cycle because the total amount of bandwidth requests from each ONU 102 is less than a predetermined value, for example (step For example, the transmission of the upstream frame from each ONU 102 to the station-side apparatus 101 is controlled so as to be able to transit to the sleep state, that is, to ensure the sleep period. That is, the station side apparatus 101 calculates the transmission timing and transmission possible time of the upstream frame of each ONU 102 so that it can transit to the sleep state (step S4).

  For example, the station apparatus 101 controls each ONU 102 so that the transmission of the upstream frame from each ONU 102 to the station apparatus 101 is performed within a predetermined interval.

  More specifically, the station apparatus 101 continues the grant time for each ONU 102, that is, an uplink frame transmission permission period, in order to extend the non-allocation period in which there is no uplink traffic from the ONU 102 to the station apparatus 101. Thereby, the arrival timing of the upstream frame from each ONU 102 is concentrated in time.

  The station apparatus 101 only needs to confirm that the sleep period is secured in the next DBA cycle, and can shift to the sleep state without controlling the transmission of the upstream frame of each ONU 102. is there.

  Next, the station apparatus 101 transmits the gate frame 1 indicating the calculation result to each ONU 102 (step S5).

  In parallel with the above operations, the station apparatus 101 receives the upstream frame 0 transmitted from each ONU 102. The upstream frame 0 is a frame transmitted by each ONU 102 according to the grant indicated by the gate frame transmitted before the gate frame 1 transmitted by the station side device 101 in the previous DBA cycle.

  In the next DBA cycle, the station apparatus 101 receives the report frame 2 transmitted from each ONU 102 (step S6).

  Next, the station side apparatus 101 calculates the total amount of bandwidth requests from each ONU 102 based on the report frame 2 received from each ONU 102 (step S7).

  For example, since the total amount of bandwidth requests from each ONU 102 is equal to or greater than a predetermined value, the station apparatus 101 determines that the transition to the sleep state cannot be made in the next DBA cycle (step S8). Note that this is an example, and the station apparatus 101 may transition to the sleep state continuously in a plurality of DBA cycles.

  Then, since the station side apparatus 101 cannot transition to the sleep state in the next DBA cycle, the station side apparatus 101 calculates the transmission timing and transmission possible time of the upstream frame of each ONU 102 as usual (step S9).

  Next, the station apparatus 101 transmits the gate frame 2 indicating the calculation result to each ONU 102 (step S10).

  In parallel with the above operations, the station apparatus 101 receives the upstream frame 1 transmitted from each ONU 102. The upstream frame 1 is a frame transmitted by each ONU 102 in accordance with the grant indicated by the gate frame 1, and is a frame transmitted continuously from each ONU 102 within a predetermined interval, for example.

  Next, the station-side apparatus 101 performs transition control to the sleep state after completing the reception of the scheduled uplink frame during the uplink frame reception period. More specifically, when all the frames corresponding to gate frame 1 are received, control unit 20 provides a sleep command to reception unit 31 and upstream reception processing unit 12 in PON transceiver 11. As a result, the operations of the reception unit 31 and the uplink reception processing unit 12 in the PON transceiver 11 are stopped, and the station side device 101 transitions to the sleep state (step S11).

  The station apparatus 101 does not need to monitor the uplink frame when determining the transition timing to the sleep state as described above. In other words, since the station side apparatus 101 knows the time when the upstream frame arrives from each ONU 102, the set time, that is, the time when the reception of the upstream frame from each ONU 102 is completed using a timer or the like is reached. A sleep command can be given.

  Next, the station-side apparatus 101 gives a wake-up command to the reception unit 31 and the upstream reception processing unit 12 in the PON transceiver 11 at a predetermined time before the next DBA cycle start timing. As a result, the operations of the reception unit 31 and the uplink reception processing unit 12 in the PON transceiver 11 are resumed, and the station side device 101 returns from the sleep state (step S12).

  FIG. 5 is a flowchart defining an operation procedure when the DBA processing unit in the station side apparatus according to the embodiment of the present invention performs the power saving process. FIG. 5 shows processing in one DBA cycle.

  Referring to FIG. 5, first, when a report frame arrives at station apparatus 101 from each ONU 102 (step S21), DBA processing unit 19 calculates the total amount of bandwidth requests from each ONU 102 based on these report frames. The calculation is performed to determine whether or not the station apparatus 101 can transition to the sleep state (step S22).

  Next, when the total amount of bandwidth requests from each ONU 102 is equal to or greater than a predetermined sleep threshold (NO in step S22), the DBA processing unit 19 cannot make the station side device 101 transition to the sleep state in the next DBA cycle. And normal bandwidth allocation calculation is performed (step S26).

  Next, the DBA processing unit 19 transmits a gate frame indicating the result of the bandwidth allocation calculation to each ONU 102 (step S25), and processes a report frame newly arrived from each ONU 102.

  On the other hand, if the total amount of bandwidth requests from each ONU 102 is less than the sleep threshold (YES in step S22), the DBA processing unit 19 can make the station side device 101 transition to the sleep state in the next DBA cycle. It is determined that there is, and a bandwidth allocation calculation is performed so that the sleep period can be secured (step S23).

  Next, the DBA processing unit 19 sets the sleep time and the wake-up time in the control unit 20 based on the calculation result (step S24). The control unit 20 controls the transceiver reception control unit 21 to output a control signal indicating a sleep command at the sleep time set from the DBA processing unit 19, and at the wake-up time set from the DBA processing unit 19 A control signal indicating a wake-up command is output.

  Next, the DBA processing unit 19 transmits a gate frame indicating the result of the bandwidth allocation calculation to each ONU 102 (step S25), and processes a report frame newly arrived from each ONU 102.

  As a method for controlling the transmission of the upstream frame from each ONU 102 to the station side apparatus 101 so that the station side apparatus 101 can secure the sleep period (step S23), for example, the following method is also conceivable. That is, the DBA processing unit 19 cannot transition to the sleep state by only one DBA cycle, but can transition to the sleep state by assigning an upstream band to each ONU 102 using two or more DBA cycles. In such a case, band allocation using two or more DBA cycles may be performed, and the station apparatus 101 may be shifted to the sleep state.

  Further, the DBA processing unit 19 does not allow the station side apparatus 101 to transition to the sleep state with only one DBA cycle, but if the transition is possible by extending the DBA cycle, the DBA processing unit 19 performs the bandwidth allocation by extending the DBA cycle. The station apparatus 101 may be shifted to the sleep state.

  Alternatively, the DBA processing unit 19 may forego bandwidth allocation for a certain DBA cycle, cause the station side device 101 to transition to the sleep state in the DBA cycle, and perform bandwidth allocation again in subsequent DBA cycles. In this case, the DBA processing unit 19 stops the allocation of the bandwidth in the PON line to each ONU 102. Then, the control unit 20 performs transition control to the sleep state during a period in which no uplink frame arrives from each ONU 102 to the station side device 101 due to the suspension of the allocation.

  FIG. 6 is a diagram illustrating an example of a method in which the DBA processing unit in the station-side apparatus according to the embodiment of the present invention determines whether or not transition to the sleep state is possible.

  Referring to FIG. 6, TDBA is the length of the DBA cycle, TRP is the time for the station side apparatus 101 to receive a report from each ONU 102, and TDAT is the frame from each ONU 102. This is the maximum time that can be received.

  When the DBA processing unit 19 calculates the total uplink bandwidth td allocated to each ONU 102, (TDAT-td) is the preparation time Tslin for the station side apparatus 101 to transition to the sleep state and the sleep state to the normal state. If it is greater than the sum of the preparation time Tslout for returning, it is determined that the station side device 101 can transition to the sleep state.

  That is, the DBA processing unit 19 determines that transition to the sleep state is possible in the station side device 101 when (TDAT−td)> (Tslin + Tslout), and when (TDAT−td) ≦ (Tslin + Tslout) Therefore, it is determined that the station-side device 101 cannot transition to the sleep state.

  Here, for example, TDBA is 500 μsec, and (Tslin + Tslout) is several tens of μsec.

  As a case where the total td of the upstream bandwidth becomes small, when the amount of reports from each ONU 102 connected to the station side device 101 is small, and for bandwidth control according to the service type contracted by the user, the station side device 101 The case where the amount of grant is small is considered. In such a case, a non-allocation period in which there is no uplink traffic from the ONU 102 to the station side device 101 occurs.

  When this non-allocation period is longer than the time required to secure the sleep period in the station side apparatus 101, the uplink frame receiving unit of the station side apparatus 101 can be operated in a power saving manner during the non-allocation period. it can.

  As a specific part of the upstream frame receiving unit that stops the operation, the optical transceiver, that is, the receiving unit 31 of the PON transceiver 11 can be considered. Further, when the lock time is sufficiently short, the CDR 41 and the deserializer 42 connected to the PON transceiver 11 can be put to sleep.

  FIG. 7 is a diagram showing an example of a data flow between the station side device and the home side device in the PON system according to the embodiment of the present invention. Here, a case where three ONUs 1 to 3 are connected to the station side device will be described.

  Referring to FIG. 7, in DBA cycle 1, station apparatus 101 calculates the total amount of bandwidth requests from ONUs 1 to 3 based on report frame 1 received from ONUs 1 to 3, and the DBA cycle is calculated from the calculation results. 2, it is determined that a transition to the sleep state is possible.

  Then, the station side device 101 calculates the transmission timing and the transmittable time of the upstream frames of the ONUs 1 to 3 so that the sleep state can be transited, that is, the sleep period can be secured, and the gate frame 1 indicating the calculation result is calculated. It transmits to ONU1-3 (timing ta). The transmission timing of the gate frame 1 may be any timing at which each ONU can transmit a report frame in the next DBA cycle.

  Further, the station side device 101 receives the upstream frame 0 transmitted from the ONUs 1 to 3. This upstream frame 0 is a frame transmitted by the ONUs 1 to 3 according to the grant indicated by the gate frame transmitted by the station side device 101 in the cycle immediately before the DBA cycle 1.

  In the next DBA cycle 2, the DBA processing unit 19 calculates the total amount of bandwidth requests from the ONUs 1 to 3 based on the report frame 2 received from the ONUs 1 to 3. It is determined that the transition to the sleep state cannot be made in DBA cycle 3.

  Then, the station side apparatus 101 calculates the transmission timing and transmission possible time of the upstream frames of the ONUs 1 to 3 as usual, and transmits the gate frame 2 indicating the calculation result to the ONUs 1 to 3 (timing tb). The transmission timing of the gate frame 2 may be any timing at which each ONU can transmit a report frame in the next DBA cycle.

  Further, the station side apparatus 101 receives the upstream frame 1 transmitted from the ONU 1 and the ONU 3. The upstream frame 1 is a frame transmitted by the ONU 1 and the ONU 3 according to the grant indicated by the gate frame 1 and is a frame transmitted continuously from the ONUs 1 to 3.

  Next, when all the frames corresponding to the gate frame 1 are received, the station side device 101 transitions to the sleep state (timing tc).

  Next, the control unit 20 starts the return operation from the sleep state at a timing td that is a predetermined time before the start timing te of the next DBA cycle 3, and returns to the normal state by the timing te.

  By the way, since it is necessary for the station side device in the PON system to receive an upstream frame from each home side device, it is difficult to save power like the home side device. That is, in order for the station side apparatus to receive all the upstream frames from the connected ONUs 102, the upstream frame receiving unit cannot be operated in a power-saving manner. For this reason, in the existing PON system, the station side device normally operates all circuits even when there is no communication traffic with the ONU.

  On the other hand, in the PON system according to the embodiment of the present invention, the DBA processing unit 19 acquires traffic information indicating the amount of uplink frame traffic from each ONU 102 to the station side apparatus 101. Then, based on the traffic information acquired by the DBA processing unit 19, the control unit 20 determines whether or not the station side device 101 can transition to the sleep state in which the reception operation of the upstream frame transmitted from each ONU 102 is stopped. Judging.

  For example, in the station side device, when there is no uplink traffic load or the load is very small, it is determined that the power saving operation is possible.

  With such a configuration, it is possible to appropriately determine the transition to the sleep state based on the traffic volume, and stop the operation of the upstream frame reception circuit in the station side device 101, thereby reducing the power consumption of the station side device 101. can do. Therefore, in the PON system according to the embodiment of the present invention, power saving of the station side device can be appropriately achieved.

  In the PON system according to the embodiment of the present invention, when the DBA processing unit 19 determines that the control unit 20 can transition to the sleep state, the station-side apparatus 101 can transition to the sleep state. The transmission of the upstream frame from each ONU 102 to the station side apparatus 101 is controlled.

  With such a configuration, it is possible to lengthen the period in which no uplink traffic from each ONU 102 exists, so that the power saving effect in the station side apparatus 101 can be further enhanced.

  In the PON system according to the embodiment of the present invention, the DBA processing unit 19 controls each ONU 102 so that the transmission of the upstream frame from each ONU 102 to the station side apparatus 101 is performed within a predetermined interval.

  With such a configuration, the timing at which the upstream frame arrives from each ONU 102 can be concentrated, and the period during which the upstream frame does not arrive can be made as long as possible. Therefore, the station apparatus 101 ensures a sufficient period as the sleep period. This can increase the power saving effect.

  In the PON system according to the embodiment of the present invention, the DBA processing unit 19 stops the allocation of the bandwidth in the PON line to each ONU 102. Then, the control unit 20 performs transition control to the sleep state during a period in which no uplink frame arrives from each ONU 102 to the station side device 101 due to the suspension of the allocation.

  With such a configuration, a period in which no upstream frame arrives from each ONU 102 can be provided with certainty, so the station apparatus 101 can reliably ensure a sleep period and enhance the power saving effect.

  In the PON system according to the embodiment of the present invention, the DBA processing unit 19 includes a reception period of a bandwidth allocation request in the PON line from each ONU 102 and a scheduled reception period of an upstream frame from each ONU 102. The allocation cycle, ie DBA cycle, is repeated. Then, the control unit 20 performs transition control to the sleep state after completing the reception of the scheduled uplink frame during the uplink frame reception period.

  After receiving all the upstream frames from each ONU 102 in a certain DBA cycle, the upstream frames do not arrive from each ONU 102 until the next DBA cycle starts. With the configuration in which this period is set as the sleep period, the station apparatus 101 can secure a sufficient period as the sleep period in the operation of repeating the normal DBA cycle, so that the power saving effect can be enhanced.

  In the PON system according to the embodiment of the present invention, the station side apparatus 101 adopts a centralized DBA method in which band allocation is performed collectively based on a band allocation request from each ONU 102 in a DBA cycle. However, the present invention is not limited to this. Instead of providing a DBA cycle, the station apparatus 101 may adopt a distributed DBA method in which bandwidth allocation is performed each time a bandwidth allocation request from each ONU 102 is made. Also in the distributed DBA system, the station side apparatus 101 can set the transmission timing and the transmittable time of the upstream frame of each ONU 102 so that it can transit to the sleep state.

  Further, in the PON system according to the embodiment of the present invention, the DBA processing unit 19 calculates the sum of the upstream bandwidth allocated to each ONU 102 as traffic information indicating the traffic amount of the upstream frame from each ONU 102 to the station side device 101. However, the present invention is not limited to this. Not only the report amount from each ONU 102 and the grant amount to the ONU, but also other traffic information such as a frame accumulation amount in the uplink buffer memory 13 or an uplink rate calculated from the accumulation amount may be acquired. Good.

  In the PON system according to the embodiment of the present invention, the station apparatus 101 acquires traffic information, determines whether or not the station apparatus 101 can enter the sleep state, and controls transmission of the upstream frame of each ONU 102.

  However, the PON system 201 is not limited to such a configuration. That is, instead of the station-side device 101, devices other than the station-side device 101 and the ONU 102 in the PON system 201 acquire traffic information, determine whether the station-side device 101 can enter the sleep state, and upload each ONU 102. It may be configured to perform frame transmission control.

  The above embodiment should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

11 PON transceiver 12 upstream reception processing unit 13 upstream buffer memory 14 upstream transmission processing unit 15 SNI transceiver 16 downstream reception processing unit 17 downstream buffer memory 18 downstream transmission processing unit 19 DBA processing unit 20 control unit 21 transceiver reception control unit 31 reception unit 32 Transmitter 33 Transmitter 34 Receiver 41 CDR
42 Deserializer 43 MAC processing unit 101 Station side device 102A, 102B, 102C, 102D ONU
201 PON system SP1, SP2 Splitter OPTF Optical fiber

Claims (7)

One or a plurality of home-side devices and a station-side device for transmitting and receiving a communication signal via a communication line common to each home-side device, and the communication from each home-side device to the station-side device A power saving control method in a communication system in which signals are time-division multiplexed,
Obtaining traffic information indicating a traffic amount of the communication signal from each home-side device to the station-side device;
Determining whether or not the station side device is capable of transitioning to a sleep state based on the acquired traffic information and stopping the reception operation of the communication signal transmitted from each home side device. Power saving control method. The power saving control method further includes:
A step of controlling the transmission of the communication signal from each home device to the station side device so that the station side device can transition to the sleep state when it is determined that the station side device can transition to the sleep state; The power saving control method according to claim 1, further comprising:   The step of controlling the transmission of the communication signal controls each home device so that the transmission of the communication signal from the home device to the station device is performed within a predetermined interval. The power saving control method described in 1. In the step of controlling the transmission of the communication signal, the allocation of the band in the communication line to each home device is stopped,
The power saving control method further includes:
The said station side apparatus includes the step which becomes the said sleep state in the period when the said communication signal does not arrive at the said station side apparatus from the said each premises apparatus by the stop of the said allocation. Power saving control method. The station side device repeats an allocation cycle including a reception period of a bandwidth allocation request in the communication line from each home side device and a scheduled reception period of the communication signal from each home side device,
The power saving control method further includes:
5. The method according to claim 1, further comprising a step in which the station side device transitions to the sleep state after completing the reception of the scheduled communication signal in the reception period of the communication signal. The power saving control method described. One or a plurality of home-side devices and a station-side device for transmitting and receiving a communication signal via a communication line common to each home-side device, and the communication from each home-side device to the station-side device The station side device in a communication system in which signals are time division multiplexed,
A traffic information acquisition unit for acquiring traffic information indicating a traffic amount of the communication signal from each home-side device to the station-side device;
Based on the traffic information acquired by the traffic information acquisition unit, it is determined whether or not the station side device can transition to a sleep state in which the reception operation of the communication signal transmitted from each home device is stopped. A station-side apparatus comprising a sleep control unit for determining. One or a plurality of home-side devices and a station-side device for transmitting and receiving a communication signal via a communication line common to each home-side device, and the communication from each home-side device to the station-side device A communication system in which signals are time division multiplexed,
A traffic information acquisition unit for acquiring traffic information indicating a traffic amount of the communication signal from each home-side device to the station-side device;
Based on the traffic information acquired by the traffic information acquisition unit, it is determined whether or not the station side device can transition to a sleep state in which the reception operation of the communication signal transmitted from each home device is stopped. A communication system comprising a sleep control unit for determining.

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