JP2013098600A - Communication system, optical line terminal, and communication control method - Google Patents

Abstract

Provided are a communication system, a station side device, and a communication control method capable of stabilizing communication from a home side device to a station side device in a communication system in which a home side device can perform a sleep operation. To do.
SOLUTION: A home apparatus 202 transitions to a sleep state in which a transmission operation for transmitting a communication signal to a station apparatus 101 is stopped, returns from the sleep state, performs a transmission operation, and an expiration of a wake-up period in which the transmission operation is performed After that, the state transits to the sleep state again, or the wake-up notification is transmitted to the station side device 101 without transiting to the sleep state, and the transmission operation is continued. A bandwidth on a communication line for transmitting a wake-up notification is allocated to the home device 202. When the wake-up notification from the home-side device 202 has not arrived at the station-side device 101, the allocation of a band for transmitting information different from the wake-up notification to the home-side device 202 is limited.
[Selection] Figure 1

Description

  The present invention relates to a communication system, a station-side apparatus, and a communication control method, and more particularly to a communication system, a station-side apparatus, and a communication control method that provide a power saving function.

  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.

  As a next-generation technology of GE-PON, which is an EPON that realizes a communication speed of 1 gigabit / second, 10G-EPON standardized as IEEE 802.3av (registered trademark) -2009, that is, a communication speed of 10 gigabit / Even in EPON equivalent to seconds, the access control protocol is predicated on MPCP.

  As a function for reducing the power consumption of the PON, a CPU (Central Processing Unit), an LSI (Large Scale Integration), or a transceiver for executing a function that is unnecessary when the ONU is not communicating. A sleep function for stopping power supply to a device has been proposed.

IEEE Std 802.3ah (registered trademark) -2004

  As an example of such a power saving function, the following ONU sleep operation can be considered. That is, the ONU continues the downstream frame reception operation from the station side device while transitioning to the sleep state in which the upstream frame transmission operation to the station side device is stopped, and after the expiration of the sleep period in which the sleep state is continued. After returning from the sleep state, the transmission operation is performed, and it is determined based on the presence / absence of upstream traffic whether or not the transition to the sleep state is made again after expiration of the wake-up period for performing the transmission operation.

  In this sleep operation, when the ONU does not transition to the sleep state, the ONU transmits a wake-up notification to the station-side device, and the station-side device recognizes that the ONU returns from the sleep operation to the normal operation by the wake-up notification.

  When the ONU performs the sleep operation as described above, an upstream data frame may arrive from the ONU before the wake-up notification arrives at the station side device. In such a case, there is a possibility that the station side apparatus cannot receive the uplink data frame and is discarded.

  Further, in the sleep state, a configuration for conserving power can be considered by stopping a transmission circuit in an optical transceiver mounted on the ONU for transmitting and receiving an optical signal. In such a configuration, it is necessary to activate the optical transceiver at the transition from the sleep period to the wake-up period. In this case, if the ONU transmits an uplink data frame immediately after the start of the wake-up period, an unstable optical signal may be transmitted to the station side device before the optical output of the optical transceiver is stabilized.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to stabilize communication from a home-side device to a station-side device in a communication system in which the home-side device can perform a sleep operation. It is to provide a communication system, a station-side device, and a communication control method capable of achieving the above.

  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 signal from each home device to the station device is time division multiplexed, wherein the home device transmits the communication signal to the station device. Transition to the sleep state in which the operation is stopped, return from the sleep state, perform the transmission operation, transition to the sleep state again after expiration of the wake-up period for performing the transmission operation, or transition to the sleep state. Without transmitting a wake-up notification to the station-side device and continuing the transmission operation, and a monitoring unit for monitoring the arrival of the wake-up notification to the station-side device, and the communication for transmitting the communication signal On the line If the wake-up notification from the home-side device has not arrived at the station-side device, the home-side device is assigned a bandwidth corresponding to the wake-up notification. A bandwidth allocation unit.

  In this way, with the configuration that restricts allocation of information bandwidth different from the wake-up notification bandwidth to the premises device during sleep operation, the communication procedure regarding the order of the wake-up notification and other information is observed, Discarding communication signals in the station side device can be prevented. In addition, by receiving a wake-up notification from the home-side device and allowing the home-side device to transmit other information, the home-side device transmits a data frame or the like immediately after the start of the wake-up period. It is possible to prevent an unstable optical signal from being transmitted to the station side device before the optical output of the optical transceiver is stabilized. Therefore, in the communication system in which the home device can perform the sleep operation, it is possible to stabilize the communication from the home device to the station device.

  Preferably, the band allocation unit allocates the band with an amount different from the amount corresponding to the wake-up notification before the wake-up notification from the home-side device arrives at the station-side device. The requested bandwidth is not allocated even if requested by.

  With such a configuration, for example, in a communication system in which a home device transmits a wake-up notification and a sleep notification to a station-side device, the home-side device mistakenly transmits to the station-side device before transmitting a wake-up notification during the wake-up period. On the other hand, when requesting allocation of bandwidth for other information, this request can be ignored. For this reason, further stabilization of communication from the home side apparatus to the station side apparatus can be achieved.

  Preferably, the home-side device transmits a sleep notification to the station-side device when transitioning to the sleep state, and the amount corresponding to the sleep notification regarding the band is an amount corresponding to the wake-up notification. The bandwidth allocation unit assigns the common amount of the bandwidth to the home side device when the wake-up notification from the home side device has not arrived at the station side device. assign.

  With such a configuration, in the communication system in which the home side device transmits the wake-up notification and the sleep notification to the station side device, it is possible to appropriately perform the bandwidth allocation process and the bandwidth allocation restriction process for the home side device during the sleep operation. .

  A communication system according to another aspect of the present invention includes one or a plurality of home-side devices, and a station-side device for transmitting and receiving communication signals via a communication line common to each home-side device, A communication system in which the communication signals from each home-side device to the station-side device are time-division multiplexed, wherein the home-side device is in a sleep state in which the transmission operation for transmitting the communication signal to the station-side device is stopped When the transition to the sleep state is made, a sleep notification is transmitted to the station-side device, the return from the sleep state is performed, and the transmission operation is performed. Transition to the sleep state or transmit the wakeup notification to the station side device without transitioning to the sleep state to continue the transmission operation and monitor the arrival of the wakeup notification to the station side device Monitoring And allocating a band in the communication line for transmitting the communication signal, and when the wake-up notification from the home-side device has not arrived at the station-side device, A bandwidth allocation unit for allocating the greater bandwidth of the amount corresponding to the wake-up notification and the amount corresponding to the sleep notification.

  In this way, with the configuration that restricts allocation of information bandwidth different from the wake-up notification bandwidth to the premises device during sleep operation, the communication procedure regarding the order of the wake-up notification and other information is observed, Discarding communication signals in the station side device can be prevented. In addition, by receiving a wake-up notification from the home-side device and allowing the home-side device to transmit other information, the home-side device transmits a data frame or the like immediately after the start of the wake-up period. It is possible to prevent an unstable optical signal from being transmitted to the station side device before the optical output of the optical transceiver is stabilized. Further, in a communication system in which the home device transmits a wake-up notification and a sleep notification to the station-side device, the home-side device erroneously transmits other information to the station-side device before transmitting the wake-up notification during the wake-up period. This request can be ignored when requesting a bandwidth allocation. Therefore, in the communication system in which the home device can perform the sleep operation, it is possible to stabilize the communication from the home device to the station device.

  In order to solve the above-mentioned problem, a station-side device according to an aspect of the present invention is a station-side device for transmitting and receiving a communication signal via a communication line common to one or a plurality of home-side devices, The home side device transitions to a sleep state in which the transmission operation for transmitting the communication signal to the station side device is stopped, returns from the sleep state, performs the transmission operation, and after the expiration of the wake-up period for performing the transmission operation , Transition to the sleep state again, or transmit a wake-up notification to the station side device without transitioning to the sleep state and continue the transmission operation, and transmit the time-division multiplexed communication signal to each home side A receiving unit for receiving from a device and a band in the communication line for transmitting the communication signal are allocated to the home side device, and the wake-up notification from the home side device arrives at the station side device Shi When no includes with respect to the optical network unit, and a band allocation unit for allocating the bandwidth of the amount corresponding to the wake-up notification.

  In this way, with the configuration that restricts allocation of information bandwidth different from the wake-up notification bandwidth to the premises device during sleep operation, the communication procedure regarding the order of the wake-up notification and other information is observed, Discarding communication signals in the station side device can be prevented. In addition, by receiving a wake-up notification from the home-side device and allowing the home-side device to transmit other information, the home-side device transmits a data frame or the like immediately after the start of the wake-up period. It is possible to prevent an unstable optical signal from being transmitted to the station side device before the optical output of the optical transceiver is stabilized. Therefore, in the communication system in which the home device can perform the sleep operation, it is possible to stabilize the communication from the home device to the station device.

  A station-side device according to another aspect of the present invention is a station-side device for transmitting / receiving a communication signal via a communication line shared with one or a plurality of home-side devices, Transition to the sleep state that stops the transmission operation for transmitting the communication signal to the station side device, and when transitioning to the sleep state, transmit a sleep notification to the station side device, return from the sleep state, and transmit After the wake-up period for performing the transmission operation is completed, transition to the sleep state again or transmit the wake-up notification to the station side device without transitioning to the sleep state and continue the transmission operation. A receiving unit for receiving the time-division multiplexed communication signal from each home device, and assigning a band in the communication line for transmitting the communication signal to the home device, When the wake-up notification from the side device has not arrived at the station-side device, the larger one of the amount corresponding to the wake-up notification and the amount corresponding to the sleep notification is given to the home-side device. A bandwidth allocation unit for allocating the bandwidth.

  In this way, with the configuration that restricts allocation of information bandwidth different from the wake-up notification bandwidth to the premises device during sleep operation, the communication procedure regarding the order of the wake-up notification and other information is observed, Discarding communication signals in the station side device can be prevented. In addition, by receiving a wake-up notification from the home-side device and allowing the home-side device to transmit other information, the home-side device transmits a data frame or the like immediately after the start of the wake-up period. It is possible to prevent an unstable optical signal from being transmitted to the station side device before the optical output of the optical transceiver is stabilized. Further, in a communication system in which the home device transmits a wake-up notification and a sleep notification to the station-side device, the home-side device erroneously transmits other information to the station-side device before transmitting the wake-up notification during the wake-up period. This request can be ignored when requesting a bandwidth allocation. Therefore, in the communication system in which the home device can perform the sleep operation, it is possible to stabilize the communication from the home device to the station device.

  In order to solve the above problems, a communication control method according to an aspect of the present invention includes a station for transmitting and receiving communication signals via one or a plurality of home-side devices and a common communication line with each home-side device. A communication control method in a communication system in which the communication signal from each home device to the station device is time division multiplexed, wherein the home device communicates with the station device. Transition to a sleep state where transmission operation for transmitting a signal is stopped, return from the sleep state, perform the transmission operation, transition to the sleep state again after expiration of the wake-up period for performing the transmission operation, or Transmitting a wake-up notification to the station-side device without transitioning to a sleep state, continuing the transmission operation, monitoring the arrival of the wake-up notification to the station-side device, and for the home-side device, the above Allocating a band in the communication line for transmitting a communication signal, and in the step of allocating the band, when the wake-up notification from the home side device has not arrived at the station side device, An amount of the band corresponding to the wake-up notification is allocated to the home-side device.

  In this way, with the configuration that restricts allocation of information bandwidth different from the wake-up notification bandwidth to the premises device during sleep operation, the communication procedure regarding the order of the wake-up notification and other information is observed, Discarding communication signals in the station side device can be prevented. In addition, by receiving a wake-up notification from the home-side device and allowing the home-side device to transmit other information, the home-side device transmits a data frame or the like immediately after the start of the wake-up period. It is possible to prevent an unstable optical signal from being transmitted to the station side device before the optical output of the optical transceiver is stabilized. Therefore, in the communication system in which the home device can perform the sleep operation, it is possible to stabilize the communication from the home device to the station device.

  Further, a communication control method according to another aspect of the present invention includes 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, A communication control method in a communication system in which the communication signal from each home side device to the station side device is time-division multiplexed, wherein the home side device transmits the communication signal to the station side device. When the transition to the sleep state is made, the sleep notification is transmitted to the station side device, the return from the sleep state is performed, and the transmission operation is performed. After expiration, the transition to the sleep state is made again, or the wakeup notification is transmitted to the station side device without transitioning to the sleep state and the transmission operation is continued, and the wakeup notification arrives at the station side device And a step of allocating a band in the communication line for transmitting the communication signal to the home side device, and in the step of allocating the band, the wake-up notification from the home side device Is not arriving at the station side device, the higher bandwidth of the amount corresponding to the wake-up notification and the amount corresponding to the sleep notification is allocated to the home-side device.

  In this way, with the configuration that restricts allocation of information bandwidth different from the wake-up notification bandwidth to the premises device during sleep operation, the communication procedure regarding the order of the wake-up notification and other information is observed, Discarding communication signals in the station side device can be prevented. In addition, by receiving a wake-up notification from the home-side device and allowing the home-side device to transmit other information, the home-side device transmits a data frame or the like immediately after the start of the wake-up period. It is possible to prevent an unstable optical signal from being transmitted to the station side device before the optical output of the optical transceiver is stabilized. Further, in a communication system in which the home device transmits a wake-up notification and a sleep notification to the station-side device, the home-side device erroneously transmits other information to the station-side device before transmitting the wake-up notification during the wake-up period. This request can be ignored when requesting a bandwidth allocation. Therefore, in the communication system in which the home device can perform the sleep operation, it is possible to stabilize the communication from the home device to the station device.

  ADVANTAGE OF THE INVENTION According to this invention, in the communication system in which a home side apparatus can perform sleep operation, stabilization of the communication from a home side apparatus to a station side apparatus can be aimed at.

It is a figure which shows the structure of the PON system which concerns on embodiment of this invention. It is a figure which shows the structure of the station side apparatus in the PON system which concerns on embodiment of this invention. It is a figure which shows the structure of the home side apparatus which concerns on embodiment of this invention. It is a figure which shows an example of the format of the gate frame produced in the station side apparatus which concerns on embodiment of this invention. It is a figure which shows an example of the format of the report frame produced in the home side apparatus which concerns on embodiment of this invention. It is a flowchart which shows the operation | movement procedure at the time of the band restriction | limiting process with respect to ONU in which the station side apparatus which concerns on embodiment of this invention in sleep operation. It is a figure which shows an example of the data flow between a station side apparatus and ONU when the station side apparatus which concerns on embodiment of this invention performs a bandwidth limitation process with respect to ONU in sleep operation. It is a figure which shows an example of the data flow between a station side apparatus and ONU when the station side apparatus which concerns on embodiment of this invention performs a bandwidth limitation process with respect to ONU in sleep operation.

  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.

[Configuration and basic operation]
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 301 is, for example, a 10G-EPON, and includes ONUs 202A, 202B, 202C, and 202D, a station apparatus 101, and splitters SP1 and SP2. The ONUs 202A, 202B, 202C 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 202D 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 301, optical signals from the ONUs 202A, 202B, 202C, and 202D to the station apparatus 101 are time-division multiplexed.

  Hereinafter, 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.

  In the PON system 301, the ONU 202 can perform the sleep operation as described above. In this sleep operation, the ONU 202 makes a transition to a sleep state in which a transmission operation for transmitting an uplink frame to the station apparatus 101 is stopped, returns from the sleep state after the sleep time has elapsed, and performs the transmission operation. Then, the ONU 202 transitions to the sleep state again after expiration of the wake-up period for performing the transmission operation, or transmits a wake-up notification to the station-side apparatus 101 without transitioning to the sleep state, and continues the transmission operation.

  FIG. 2 is a diagram showing a configuration of a station side device in the PON system according to the embodiment of the present invention.

  Referring to FIG. 2, station apparatus 101 includes an uplink IF (Interface) unit 31, a reception processing unit 33, a transmission processing unit 34, a PON transmission / reception unit 35, and a control unit (a monitoring unit and a bandwidth allocation unit). ) 36, a FIFO 37 for accumulating upstream frames, and a FIFO 38 for accumulating downstream frames.

  The PON transmission / reception unit 35 transmits / receives optical signals to / from each ONU 202 via a common PON line. That is, the PON transmission / reception unit 35 is connected to the optical fiber OPTF, which is a PON line, as a master station side starting point of the PON line. The PON transmission / reception unit 35 receives an upstream optical signal of a specific wavelength, for example, a 1310 nm band, and converts it into an electrical signal so that bidirectional communication can be performed with each ONU 202 via the optical fiber OPTF. In addition to outputting, the electrical signal received from the transmission processing unit 34 is converted into a downstream optical signal of another wavelength and transmitted. For example, the PON transmission / reception unit 35 converts a 10 Gbps (gigabit / second) electrical signal received from the transmission processing unit 34 into a downstream optical signal of 1570 nm band and transmits the converted signal to each ONU 202.

  The reception processing unit 33 reconstructs a frame from the electrical signal received from the PON transmission / reception unit 35 and distributes the frame to the control unit 36 or the FIFO 37 according to the type of the frame. Specifically, the data frame is output to the FIFO 37 and the control frame is output to the control unit 36.

  The uplink IF unit 31 outputs the uplink frame stored in the FIFO 37 to the upper network. Further, when receiving a frame from the upper network, the uplink IF unit 31 outputs the frame to the FIFO 38 when the frame is a normal data frame, and outputs the frame to the control unit 36 when the frame is a control frame. .

  When receiving the control frame from the control unit 36, the uplink IF unit 31 outputs the control frame to the upper network in preference to the frame from the FIFO 37 in the interval between the frame sequences from the FIFO 37, for example.

  When the FIFO 38 or the control unit 36 has a frame to be transmitted, the transmission processing unit 34 receives the frame according to the priority order and outputs it to the PON transmission / reception unit 35.

  The control unit 36 performs station-side processing relating to control and management of the PON line such as MPCP and OAM. That is, by exchanging the MPCP message and the OAM message with each ONU 202 connected to the PON line, the upstream access control including the registration, withdrawal and bandwidth allocation of the ONU 202, the downstream access control, and the sleep instruction to the ONU 202 are included. The operation management of the ONU 202 is performed.

  For example, the control unit 36 allocates the upstream bandwidth in the PON line to each ONU 202 based on the upstream bandwidth allocation request in the PON line received from each ONU 202. Specifically, the control unit 36 allocates the bandwidth in the PON line to the ONU 202 based on the report frame indicating the bandwidth allocation request in the PON line received from the ONU 202, that is, transmits a gate frame describing the grant to the ONU 202. .

  The control unit 36 allocates an upstream band in the PON line to each ONU 202 so that the arrival timing of the upstream frame from each ONU 202 does not overlap in time in the station apparatus 101. The control unit 36 notifies the ONU 202 of the transmission start timing of the uplink frame and the transmittable data length using the gate frame.

  Further, for example, the control unit 36 includes an allocation period including a reception period of an uplink bandwidth allocation request on the PON line from each ONU 202, a calculation period of a bandwidth allocation amount, and a scheduled uplink frame reception period from each ONU 202. That is, a DBA (Dynamic Bandwidth Allocation) cycle is repeated.

  FIG. 3 is a diagram showing the configuration of the home-side apparatus according to the embodiment of the present invention.

  Referring to FIG. 3, the ONU 202 includes a PON port 21, an optical reception processing unit 22, a buffer memory 23, a transmission processing unit 24, a UNI (User Network Interface) port 25, a reception processing unit 26, and a buffer. A memory 27, an optical transmission processing unit 28, and a control unit 29 are provided.

  The optical reception processing unit 22 receives the downstream optical signal transmitted from the station side device 101 via the PON port 21, converts it into an electrical signal, reconstructs the frame from the electrical signal, and according to the type of the frame The frame is distributed to the control unit 29 or the transmission processing unit 24 via the buffer memory 23. Specifically, the optical reception processing unit 22 outputs a data frame to the transmission processing unit 24 and outputs a control frame to the control unit 29.

  The transmission processing unit 24 transmits the data frame received from the optical reception processing unit 22 to a user terminal such as a personal computer (not shown) via the UNI port 25.

  The reception processing unit 26 outputs the data frame received from the user terminal via the UNI port 25 to the optical transmission processing unit 28 via the buffer memory 27.

  The control unit 29 performs home-side processing related to control and management of the PON line such as MPCP and OAM. That is, various controls such as access control are performed by exchanging MPCP messages and OAM messages with the station-side apparatus 101 connected to the PON line. The control unit 29 generates a control frame including various control information and outputs it to the optical transmission processing unit 28 via the buffer memory 27.

  The optical transmission processing unit 28 converts the data frame received from the reception processing unit 26 and the control frame received from the control unit 29 into an optical signal, and transmits the optical signal to the station apparatus 101 via the PON port 21.

  In addition, the control unit 29 receives a control frame indicating a sleep instruction from the station-side device 101, and performs sleep control for making a transition to a sleep state in which, for example, the operation of the optical transmission processing unit 28 is stopped. In addition, the control unit 29 transmits a control frame indicating a sleep notification, which is a notification of transition to the sleep state, to the station apparatus 101.

  Further, after returning from the sleep state, the control unit 29 determines whether or not the sleep state can be continued, and when determining that the sleep state can be continued, the control unit 29 transmits a sleep notification to the station-side device 101, When the predetermined wake-up period ends, the state transitions to the sleep state again. On the other hand, when the control unit 29 determines that the sleep state cannot be continued after returning from the sleep state, the control unit 29 transmits a wake-up notification to the station-side device 101 and continues normal operation.

  When the control unit 29 receives the control frame indicating the sleep instruction from the station side device 101 and determines that the sleep state cannot be changed, the control unit 29 does not change to the sleep state and transmits the control frame indicating the wake-up notification. You may transmit to the side apparatus 101. FIG.

  FIG. 4 is a diagram showing an example of the format of the gate frame created in the station side apparatus according to the embodiment of the present invention.

  Referring to FIG. 4, a gate frame includes a header field, a grant number / flag field, a start time field and a data length field of grants # 1 to # 4, a padding field, and an FCS (Frame Check Sequence) field. Have

  In the grant number / flag field, the number of grants designated in the gate frame can be set.

  More specifically, in the gate frame, 0 to a maximum of 4 grants can be set. When a value less than 4 is set as the number of grants, a padding field is added for the start time field and data length field of unused grant #n. As a result, the frame length of the gate frame is always kept at, for example, 64 bytes.

  In the grant number / flag field, it is possible to set a forced report flag indicating whether or not to transmit a report using a designated grant.

  More specifically, the grant for which the forced report flag is set is used as a report grant, and the ONU 202 must always transmit a report frame for the grant for which the forced report flag is set.

  In the PON system according to the embodiment of the present invention, for example, the number of grants is set to 2, and the forced report flag is set to grant # 1 on and grant # 2 off. That is, one gate frame provides grant # 1 for report frame and grant # 2 for control frame or data frame. Grant # 1 is the minimum amount of data that can be transmitted by one report frame, and grant # 2 is the amount of data according to the report value notified to the station apparatus 101 by the ONU 202, for example.

  FIG. 5 is a diagram showing an example of a format of a report frame created in the home side apparatus according to the embodiment of the present invention.

  Referring to FIG. 5, the report frame includes a header field, a Qset number field, a report bitmap field, a Q # 0 report to Q # 7 report field, a padding field, and an FCS field.

  In the Qset number field, the number of Qsets is set. A report bitmap field and a Q # n report field are provided for the number of Qsets. In FIG. 5, one Qset is representatively shown.

  In the report bitmap field, a bitmap indicating how many Q # n reports are provided in Qset is set.

  For example, when the bit string “00011111” is set, the number of Q reports is five.

  In the PON system according to the embodiment of the present invention, for example, the number of Qsets = 2 and the report bitmap = “00011111”. That is, two Qsets having five Q reports are set in one report frame.

  Further, for example, in the ONU 202, the buffer memory 27 has five types of upstream queues according to the priority of upstream frames. More specifically, there are four types of priorities for uplink data frames, and the other one is a queue for control frames, and the priority of control frames is the highest.

  When there is no uplink traffic, the ONU 202 transmits a zero report in which the Q report values of all Qsets are 0 to the station apparatus 101. Further, when there is uplink traffic, the ONU 202 transmits a non-zero report in which a value is set in any Q report to the station apparatus 101. The ONU 202 sets a report value according to the amount of uplink frame data accumulated in the uplink queue.

[Operation]
Next, band limiting processing for an ONU during sleep operation by the station-side apparatus according to the embodiment of the present invention will be described with reference to the drawings.

  Upon receiving the sleep notification, the control unit 36 in the station side device 101 restricts bandwidth allocation on the PON line to the ONU 202 that is the transmission source of the sleep notification. For example, the control unit 36 also limits the bandwidth for transmitting the wake-up notification and the sleep notification to the ONU 202 in the sleep state.

  In addition, the control unit 36 allocates a bandwidth in the PON line for transmitting the wake-up notification or the sleep notification to the ONU 202 that has returned from the sleep state.

  The control unit 29 in the ONU 202 sends a wake-up notification or a sleep notification to another control frame within the range of the allocated bandwidth of the PON line notified from the station-side device 101, specifically, within the grant # 2. The data frame is preferentially transmitted to the station apparatus 101. Note that the report frame can be transmitted according to Grant # 1 regardless of Grant # 2.

  Then, the control unit 36 monitors the arrival of the wake-up notification to the station-side device 101. If the wake-up notification from the ONU 202 that has returned from the sleep state has not arrived at the station-side device 101, the control unit 36 An amount of bandwidth corresponding to the wake-up notification or sleep notification is allocated, that is, the bandwidth allocation for transmitting information different from the wake-up notification and sleep notification is limited.

  For example, even if the control unit 36 is requested by the ONU 202 to allocate a bandwidth in the PON line for transmitting information different from the wake-up notification and the sleep notification before receiving the wake-up notification from the ONU 202 that has returned from the sleep state, Does not allocate the requested bandwidth. In other words, the control unit 36 continues to limit the allocation for bands other than the wake-up notification and the sleep notification.

  On the other hand, when receiving the wake-up notification from the ONU 202 that has returned from the sleep state, the control unit 36 releases the restriction on bandwidth allocation in the PON line to the ONU 202 that is the transmission source of the wake-up notification.

  FIG. 6 is a flowchart showing an operation procedure when the station side apparatus according to the embodiment of the present invention performs the bandwidth limitation process on the ONU during the sleep operation.

  With reference to FIG. 6, first, the control unit 36 in the station-side device 101 acquires traffic information indicating, for example, the uplink traffic volume and downlink traffic volume of the target ONU. This amount of traffic may be, for example, the number of frames, or the amount of data such as bytes and bits. If the control unit 36 determines that the target ONU can transition to the sleep state because the traffic volume of the target ONU is small, the control unit 36 transmits a sleep instruction to the target ONU and sleeps until the next wake-up timing in the sleep operation. Let This sleep instruction includes, for example, the transition timing to the sleep state and the sleep time (step S1).

  Next, when receiving a sleep notification from the target ONU (step S2), the control unit 36 starts a timer corresponding to the target ONU (step S3). For example, the timer counts down with the sleep time as an initial value. The control unit 36 determines that the target ONU is in the sleep state until the timer expires, that is, reaches zero.

  Next, when the timer has not expired (NO in step S4), the control unit 36 sets the bandwidth allocation amount for the control frame or data frame for the target ONU, that is, the grant to zero for each DBA cycle. A frame is created (step S5) and transmitted to the target ONU (step S6).

  Here, if the timer has not expired (NO in step S4), the control unit 36 may receive a bandwidth allocation request for a control frame or a data frame, that is, a report frame from the target ONU (YES in step S7). The bandwidth allocation request is ignored, and a gate frame is generated and transmitted with the grant for the control frame or data frame set to zero (step S8).

  Next, when the timer expires (YES in step S4), the control unit 36 determines that the target ONU has returned from the sleep state, and transmits a sleep notification or a wake-up notification for each DBA cycle. Is assigned to the target ONU. That is, the control unit 36 creates a gate frame in which a grant for sleep notification or wake-up notification is set (step S9), and transmits the gate frame to the target ONU (step S10).

  Next, when the wake-up notification is received from the target ONU (YES in step S11), the control unit 36 releases the band allocation limitation for the target ONU, that is, the grant limitation. That is, the control unit 36 calculates a bandwidth allocation amount for the target ONU based on a bandwidth allocation request from the target ONU, that is, a report value indicated by the report frame (step S12).

  On the other hand, when the wake-up notification is not received from the target ONU (NO in step S11), the control unit 36 may receive a bandwidth allocation request for a control frame or a data frame, that is, a report frame from the target ONU (step S13). YES), the bandwidth allocation request is ignored, and a gate frame in which a sleep notification or wake-up notification grant is set is created and transmitted (step S14).

  Then, until the control unit 36 receives a wake-up notification or a sleep notification from the target ONU (YES in step S11 or YES in step S15), the control unit 36 sets the grant for the sleep notification or the wake-up notification for each DBA cycle. Creation and transmission are performed (step S9 and step S10).

  On the other hand, when the control unit 36 receives a sleep notification from the target ONU (YES in step S15), the control unit 36 starts the timer corresponding to the target ONU again (step S3).

  FIG. 7 is a diagram illustrating an example of a data flow between the station side device and the ONU when the station side device according to the embodiment of the present invention performs the bandwidth limitation process on the ONU during the sleep operation.

  Referring to FIG. 7, at timing t0, station apparatus 101 determines that the target ONU is to be shifted to the sleep state, and transmits a sleep instruction SI to the target ONU. The target ONU receives the sleep instruction SI and transmits a sleep notification SR to the station apparatus 101.

  Next, the station-side measure 101 receives the sleep notification SR and starts a timer corresponding to the target ONU at a timing t1 corresponding to the sleep start timing of the target ONU. The station apparatus 101 sets an initial value corresponding to the sleep time of the target ONU in the timer so that the timer expires at a timing t2 corresponding to the timing when the target ONU returns from the sleep state.

  Then, the station side measure 101 creates a gate frame GZ in which the grant for the control frame or the data frame is set to zero for each DBA cycle from the timing t1 to the timing t2, and transmits the gate frame GZ to the target ONU. Specifically, in the frame format shown in FIG. 4, for example, the station apparatus 101 transmits a gate frame in which the data length field of grant # 2 is set to zero. Further, for example, the station apparatus 101 transmits a gate frame in which the forced report flag of grant # 1 is set to ON in order to maintain synchronization with the station apparatus 101 even for the target ONU in the sleep state. .

  Next, when the timer expires at timing t2, the station-side measure 101 creates a gate frame GX in which a grant for the sleep notification SR or the wake-up notification WR is set for each DBA cycle, and transmits the gate frame GX to the target ONU. Specifically, in the frame format shown in FIG. 4, the station apparatus 101 sets a grant amount for sleep notification or wake-up notification in the data length field of grant # 2 for the target ONU that has returned from the sleep state. Transmit the gate frame.

  Next, the station-side measure 101 receives a sleep notification from the target ONU at timing t3. Thereby, the station side measure 101 recognizes that the target ONU transitions again to the sleep state at the timing t4 when the wake-up period of the target ONU expires.

  Next, the station-side measure 101 starts a timer corresponding to the target ONU at a timing t4 corresponding to the sleep start timing of the target ONU. The station apparatus 101 sets an initial value corresponding to the sleep time of the target ONU in the timer so that the timer expires when the target ONU returns from the sleep state.

  Then, the station-side measure 101 creates a gate frame GZ in which the grant for the control frame or the data frame is set to zero for each DBA cycle until the timing when the target ONU returns from the sleep state after the timing t4. Send to.

  FIG. 8 is a diagram illustrating an example of a data flow between the station-side apparatus and the ONU when the station-side apparatus according to the embodiment of the present invention performs the bandwidth limitation process on the ONU that is in the sleep operation.

  Referring to FIG. 8, at timing t10, station apparatus 101 determines that the target ONU is to be shifted to the sleep state, and transmits a sleep instruction SI to the target ONU. The target ONU receives the sleep instruction SI and transmits a sleep notification SR to the station apparatus 101.

  Next, the station side measure 101 receives the sleep notification SR and starts a timer corresponding to the target ONU at a timing t11 corresponding to the sleep start timing of the target ONU. The station apparatus 101 sets an initial value corresponding to the sleep time of the target ONU in the timer so that the timer expires at a timing t12 corresponding to the timing when the target ONU returns from the sleep state.

  Then, the station-side measure 101 creates a gate frame GZ in which the grant for the control frame or the data frame is set to zero for each DBA cycle from timing t11 to timing t12, and transmits it to the target ONU. Specifically, in the frame format shown in FIG. 4, for example, the station apparatus 101 transmits a gate frame in which the data length field of grant # 2 is set to zero. Further, for example, the station apparatus 101 transmits a gate frame in which the forced report flag of grant # 1 is set to ON in order to maintain synchronization with the station apparatus 101 even for the target ONU in the sleep state. .

  Next, when the timer expires at timing t12, the station-side measure 101 creates a gate frame GX in which a grant for the sleep notification SR or the wake-up notification WR is set for each DBA cycle, and transmits the gate frame GX to the target ONU. Specifically, in the frame format shown in FIG. 4, the station apparatus 101 sets a grant amount for sleep notification or wake-up notification in the data length field of grant # 2 for the target ONU that has returned from the sleep state. Transmit the gate frame.

  Next, the station-side measure 101 receives a report frame R1 indicating a report value for transmitting a control frame or data frame other than the report frame from the target ONU at timing t13. However, since the station side measure 101 has not received the wake-up notification WR from the target ONU, it ignores this report frame and continues to create and transmit the gate frame GX in which the sleep notification SR or the wake-up notification WR grant is set. To do.

  Next, the station-side measure 101 receives the wake-up notification WR from the target ONU at timing t14. Thereby, the station-side measure 101 cancels the grant restriction for the target ONU.

  Next, the station-side measure 101 receives a report frame R2 indicating a report value for transmitting a control frame or data frame other than the report frame from the target ONU at timing t15.

  Then, the station-side measure 101 calculates a grant to be given to the target ONU based on the report value indicated by the report frame R2, creates a gate frame GY indicating the calculated grant, and transmits it to the target ONU.

  Thereafter, the target ONU transmits a new report frame R3 to the station apparatus 101, and transmits a control frame or a data frame FR to the station apparatus 101 according to the grant indicated by the gate frame GY received from the station apparatus 101. To do.

  As described above, the station apparatus 101 gives the target ONU a grant for the target ONU to transmit the wake-up notification or the sleep notification after the timer expires at the timing t12, that is, after the sleep period of the target ONU ends. In this case, the grant for the control frame or the data frame is set to a minimum value for the target ONU to transmit the control frame indicating the wake-up notification or the sleep notification regardless of the report value notified from the target ONU. .

  Then, after receiving the wake-up notification from the target ONU, the station-side apparatus 101 gives a grant to the target ONU based on the report value notified from the target ONU so that transmission of other uplink frames is possible.

  The station-side measure 101 may be configured to transmit the gate frame GX in which the sleep notification SR or the wake-up notification WR grant is set to the ONU 202 in the period from the timing t11 to the timing t12. Even in this case, the ONU 202 transmits the sleep notification SR or the wake-up notification WR to the station-side device 101 during the wake-up period.

  Further, in the PON system according to the embodiment of the present invention, the ONU 202 is configured to transmit the sleep notification to the station side device 101 when transitioning to the sleep state. However, the present invention is not limited to this. The ONU 202 may be configured to transition to the sleep state again without transmitting the sleep notification to the station apparatus 101. In this case, the station-side apparatus 101 determines that the ONU 202 is performing a sleep operation until receiving a wake-up notification from the ONU 202, grasps the length of the wake-up period of the ONU 202 and the length of the sleep period, and performs bandwidth allocation processing. In addition, it is possible to perform bandwidth allocation limiting processing.

  By the way, when the ONU performs the sleep operation as described above, if the upstream data frame arrives from the ONU before the wake-up notification arrives, the station side device cannot receive the upstream data frame and is discarded. There is a possibility that. Further, in the configuration in which power saving is achieved by stopping the transmission circuit in the optical transceiver for transmitting and receiving optical signals in the sleep state, the ONU transmits the upstream data frame immediately after the start of the wake-up period. Then, an unstable optical signal may be transmitted to the station side device before the optical output of the optical transceiver is stabilized.

  On the other hand, in the PON system according to the embodiment of the present invention, the control unit 36 in the station side device 101 monitors the arrival of the wake-up notification from the ONU 202 during the sleep operation to the station side device 101. When the wake-up notification from the ONU 202 during the sleep operation has not arrived at the station-side apparatus 101, the control unit 36 allocates a bandwidth on the PON line corresponding to the wake-up notification to the ONU 202.

  In this way, the configuration for restricting allocation of the information band different from the wake-up notification band to the ONU 202 during the sleep operation observes the communication procedure regarding the order of the wake-up notification and other upstream frames, The upstream frame in the side apparatus 101 can be prevented from being discarded. In addition, by receiving a wake-up notification from the ONU 202 and allowing other ON frames to be transmitted to the ONU 202, it is possible to prevent the ONU from transmitting a data frame or the like immediately after the start of the wake-up period. It is possible to prevent an unstable optical signal from being transmitted to the station apparatus 101 before the optical output is stabilized.

  Therefore, in the PON system according to the embodiment of the present invention, it is possible to stabilize the communication from the home side device to the station side device in the communication system in which the home side device can perform the sleep operation.

  Further, in the PON system according to the embodiment of the present invention, before receiving the wake-up notification from the ONU 202, the control unit 36 is requested from the ONU 202 to allocate bandwidth in the PON line whose amount is different from the amount corresponding to the wake-up notification. However, the requested bandwidth is not allocated.

  With such a configuration, for example, in a PON system in which the ONU 202 transmits a wake-up notification and a sleep notification to the station-side device 101, the ONU 202 erroneously notifies the station-side device 101 before transmitting the wake-up notification during the wake-up period. This request can be ignored when requesting allocation of a bandwidth for another upstream frame. For this reason, further stabilization of communication from the home side apparatus to the station side apparatus can be achieved.

  Further, in the PON system according to the embodiment of the present invention, the control unit 29 in the ONU 202 transmits a sleep notification to the station-side apparatus 101 when transitioning to the sleep state. Regarding the bandwidth in the PON line, the amount corresponding to the sleep notification is the same as the amount corresponding to the wake-up notification. The control unit 36 in the station side device 101 monitors arrival of a wake-up notification from the ONU 202 during the sleep operation to the station side device 101. When the wake-up notification from the ONU 202 during the sleep operation has not arrived at the station-side device 101, the control unit 36 allocates a bandwidth in the common amount of the PON line to the ONU 202.

  With such a configuration, in the PON system in which the ONU 202 transmits a wake-up notification and a sleep notification to the station-side device 101, it is possible to appropriately perform a bandwidth allocation process and a bandwidth allocation restriction process for the ONU 202 during the sleep operation.

  With such a configuration, in the PON system in which the ONU 202 transmits the wake-up notification and the sleep notification to the station-side device 101, the ONU 202 erroneously transmits another signal to the station-side device 101 before transmitting the wake-up notification during the wake-up period. Since this request can be ignored when the allocation of the bandwidth for the upstream frame is requested, the communication from the home side apparatus to the station side apparatus can be further stabilized.

  In the PON system according to the embodiment of the present invention, the bandwidth amount corresponding to the wake-up notification and the bandwidth amount corresponding to the sleep notification may be different. In this case, when the wake-up notification from the ONU 202 during the sleep operation has not arrived at the station-side device 101, the control unit 36 sends an amount corresponding to the wake-up notification and an amount corresponding to the sleep notification to the ONU 202. Allocate the bandwidth in the PON line of the larger one.

  In this way, the configuration for restricting allocation of the information band different from the wake-up notification band to the ONU 202 during the sleep operation observes the communication procedure regarding the order of the wake-up notification and other upstream frames, The upstream frame in the side apparatus 101 can be prevented from being discarded. In addition, by receiving a wake-up notification from the ONU 202 and allowing other ON frames to be transmitted to the ONU 202, it is possible to prevent the ONU from transmitting a data frame or the like immediately after the start of the wake-up period. It is possible to prevent an unstable optical signal from being transmitted to the station apparatus 101 before the optical output is stabilized. Further, in the PON system in which the ONU 202 transmits the wake-up notification and the sleep notification to the station-side device 101, the ONU 202 erroneously transmits another wake-up frame to the station-side device 101 before transmitting the wake-up notification during the wake-up period. When requesting bandwidth allocation, this request can be ignored. Therefore, in the communication system in which the home device can perform the sleep operation, it is possible to stabilize the communication from the home device to the station device.

  In the PON system according to the embodiment of the present invention, the control unit 36 in the station-side device 201 performs a bandwidth allocation process and a bandwidth allocation restriction process for the ONU 202.

  However, the PON system 301 is not limited to such a configuration. In other words, instead of the station-side device 201, a device other than the station-side device 101 and the ONU 202 in the PON system 301 may perform a bandwidth allocation process and a bandwidth allocation restriction process for the ONU 202.

  In this case, the PON system 301 includes a monitoring unit and a bandwidth allocation unit.

  For example, in a PON system in which the ONU 202 transmits a wake-up notification and a sleep notification to the station-side device 101, the monitoring unit monitors the arrival of the wake-up notification from the ONU 202 during the sleep operation to the station-side device 101.

  Then, when the wake-up notification from the ONU 202 during the sleep operation has not arrived at the station-side device 101, the bandwidth allocator allocates a bandwidth in the PON line corresponding to the wake-up notification to the ONU 202, In addition, a bandwidth in the PON line corresponding to the sleep notification is allocated.

  Further, for example, the bandwidth allocation unit allocates bandwidth in the PON line for transmitting information different from the wake-up notification and the sleep notification before the wake-up notification from the ONU 202 during the sleep operation arrives at the station-side device 101. Even when requested by the ONU 202, the requested bandwidth is not allocated.

  When the bandwidth amount corresponding to the wake-up notification and the bandwidth amount corresponding to the sleep notification are different, the bandwidth allocation unit determines that the wake-up notification from the ONU 202 during the sleep operation has not arrived at the station-side device 101. The ONU 202 is assigned a bandwidth in the PON line that is larger of the amount corresponding to the wake-up notification and the amount corresponding to the sleep notification.

  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.

21 PON port 22 optical reception processing unit 23 buffer memory 24 transmission processing unit 25 UNI port 26 reception processing unit 27 buffer memory 28 optical transmission processing unit 29 control unit 31 uplink IF unit 33 uplink IF unit 34 transmission processing unit 35 PON transmission / reception Unit 36 Control unit (monitoring unit and bandwidth allocation unit)
37,38 FIFO
101 Station side equipment (OLT)
202A, 202B, 202C, 202D Home side equipment (ONU)
301 PON system SP1, SP2 Splitter OPTF Optical fiber

Claims (8)

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,
The home-side device transitions to a sleep state in which a transmission operation for transmitting the communication signal to the station-side device is stopped, returns from the sleep state, performs the transmission operation, and an expiration of a wake-up period for performing the transmission operation After that, the transition to the sleep state again, or the wake-up notification is transmitted to the station side device without transitioning to the sleep state, and the transmission operation is continued.
A monitoring unit for monitoring arrival of the wake-up notification to the station side device;
A bandwidth in the communication line for transmitting the communication signal is allocated, and when the wake-up notification from the home-side device has not arrived at the station-side device, the wake-up notification is sent to the home-side device. A bandwidth allocating unit for allocating an amount of the bandwidth corresponding to.   The bandwidth allocation unit is requested from the home device to allocate an amount of the bandwidth different from the amount corresponding to the wakeup notification before the wakeup notification from the home device arrives at the station device. However, the communication system according to claim 1, wherein the requested bandwidth allocation is not performed. The home side device transmits a sleep notification to the station side device when transitioning to the sleep state,
Regarding the bandwidth, the amount corresponding to the sleep notification is the same as the amount corresponding to the wake-up notification,
The bandwidth allocation unit allocates the common amount of the bandwidth to the home side device when the wake-up notification from the home side device has not arrived at the station side device. Or the communication system of Claim 2. 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,
The home-side device transitions to a sleep state in which a transmission operation for transmitting the communication signal to the station-side device is stopped. When the home-side device transitions to the sleep state, the home-side device transmits a sleep notification to the station-side device. After returning from the state, the transmission operation is performed, and after the wake-up period for performing the transmission operation is completed, the sleep state is again transitioned to, or the wake-up notification is transmitted to the station side device without transitioning to the sleep state. To continue the transmission operation,
A monitoring unit for monitoring arrival of the wake-up notification to the station side device;
A bandwidth in the communication line for transmitting the communication signal is allocated, and when the wake-up notification from the home-side device has not arrived at the station-side device, the wake-up notification is sent to the home-side device. And a bandwidth allocating unit for allocating the greater of the amount corresponding to the sleep notification and the amount corresponding to the sleep notification. A station-side device for transmitting and receiving communication signals via a communication line common to one or more home-side devices,
The home-side device transitions to a sleep state in which a transmission operation for transmitting the communication signal to the station-side device is stopped, returns from the sleep state, performs the transmission operation, and an expiration of a wake-up period for performing the transmission operation After that, the transition to the sleep state again, or the wake-up notification is transmitted to the station side device without transitioning to the sleep state, and the transmission operation is continued.
A receiving unit for receiving the communication signal time-division multiplexed from each of the home-side devices;
When the bandwidth on the communication line for transmitting the communication signal is allocated to the home side device and the wake-up notification from the home side device has not arrived at the station side device, the home side A station side apparatus comprising: a band allocation unit for allocating an amount of the band corresponding to the wake-up notification to the apparatus. A station-side device for transmitting and receiving communication signals via a communication line common to one or more home-side devices,
The home-side device transitions to a sleep state in which a transmission operation for transmitting the communication signal to the station-side device is stopped. When the home-side device transitions to the sleep state, the home-side device transmits a sleep notification to the station-side device. After returning from the state, the transmission operation is performed, and after the wake-up period for performing the transmission operation is completed, the sleep state is again transitioned to, or the wake-up notification is transmitted to the station side device without transitioning to the sleep state. To continue the transmission operation,
A receiving unit for receiving the communication signal time-division multiplexed from each of the home-side devices;
When the bandwidth on the communication line for transmitting the communication signal is allocated to the home side device and the wake-up notification from the home side device has not arrived at the station side device, the home side A station-side device, comprising: a bandwidth allocating unit for allocating, to the device, the bandwidth corresponding to the larger amount corresponding to the wake-up notification and the amount corresponding to the sleep notification. 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 control method in a communication system in which signals are time-division multiplexed,
The home-side device transitions to a sleep state in which a transmission operation for transmitting the communication signal to the station-side device is stopped, returns from the sleep state, performs the transmission operation, and an expiration of a wake-up period for performing the transmission operation After that, the transition to the sleep state again, or the wake-up notification is transmitted to the station side device without transitioning to the sleep state, and the transmission operation is continued.
Monitoring the arrival of the wake-up notification to the station side device;
Allocating a band in the communication line for transmitting the communication signal to the home side device,
In the step of allocating the bandwidth, if the wake-up notification from the home-side device has not arrived at the station-side device, the home-side device is assigned the amount of the bandwidth corresponding to the wake-up notification. Assigned communication control method. 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 control method in a communication system in which signals are time-division multiplexed,
The home-side device transitions to a sleep state in which a transmission operation for transmitting the communication signal to the station-side device is stopped. When the home-side device transitions to the sleep state, the home-side device transmits a sleep notification to the station-side device. After returning from the state, the transmission operation is performed, and after the wake-up period for performing the transmission operation is completed, the sleep state is again transitioned to, or the wake-up notification is transmitted to the station side device without transitioning to the sleep state. To continue the transmission operation,
Monitoring the arrival of the wake-up notification to the station side device;
Allocating a band in the communication line for transmitting the communication signal to the home side device,
In the step of allocating the bandwidth, when the wake-up notification from the home-side device has not arrived at the station-side device, the amount corresponding to the wake-up notification and the sleep notification are sent to the home-side device. A communication control method for allocating the greater bandwidth among the amounts corresponding to the.

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