JP2011135501A - Communication system, master station device, and slave station device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a communication system which can enhance a power saving effect. <P>SOLUTION: Each of ONUs 2-1 to 2-n includes a PON controller 28 for informing an OLT 1 of a mode for each logical link and determining a transmission time zone as an up-link transmission time zone on the basis of an allocation result from the OLT 1, and a device controller 27 for stopping the up-link transmission function in time zones other than the transmission time zone. The OLT 1 includes a PON controller 17 for using the informed mode for each logical link as mode information, and a zone updating period manager 18 for determining a zone request period on the basis of the mode information and a set period for each logical link. The PON controller 17 allocates an up-link transmission zone to associated one of the ONUs 2-1 to 2-n for each zone request period and transmits an allocated result for each zone request period. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a communication system constituting a PON (Passive Optical Network) system in which a master station device is connected to a slave station device in a one-to-many manner.

  In recent years, a PON system has been used for an access network that connects each home or company to an upper network. The PON is a system in which a master station device (OLT: Optical Line Terminal) and a number of slave station devices (ONU: Optical Network Unit) are connected one-to-many using optical fibers and splitters.

  In such a one-to-many PON system, when performing uplink data communication that is communication from the ONU to the OLT, the following bandwidth allocation processing is performed. First, the ONU transmits a buffer amount notification for notifying the OLT of the buffer amount of its own data. The OLT allocates a band to each ONU based on the buffer amount notification of each ONU, and transmits an allocated band notification indicating the transmission start time and transmission time for each ONU as an allocation result. The ONU receives the allocated bandwidth notification addressed to itself from the OLT, and transmits uplink data according to the content of the allocated bandwidth notification.

  As a conventional PON system, for example, there is a 10G-EPON (10 Gigabit Ethernet (registered trademark) PON) system disclosed in Non-Patent Document 1 below. The PON system described in Non-Patent Document 1 below has a data transmission rate of 10 Gbit / s for communication in the vertical direction, and performs bidirectional communication by wavelength multiplexing using different wavelengths in the vertical direction. Further, when the ONU transmits uplink data, the data is transmitted by a time division multiplexing method in which the uplink band is divided and used by a plurality of ONUs.

  On the other hand, power saving of the ONU has been studied in recent years. For example, Non-Patent Document 2 below discloses a power save sequence between the OLT and the ONU for power saving of the ONU. In this power save sequence, a sleep request for entering a sleep (power saving) mode is transmitted from the ONU, and a sleep instruction is transmitted to the ONU in the OLT that has received the request. Then, the ONU that has received the sleep instruction enters the sleep mode.

  Thereafter, when returning from the sleep mode, the ONU transmits an activation request to the OLT. The OLT that has received the activation request transmits an activation instruction to the ONU, and the ONU that has received the activation instruction returns to the normal mode. The ONU stops the optical transmitter and various devices for transmitting uplink data during the sleep mode while shifting to the sleep mode. In this way, power saving of the ONU is realized.

IEEE (Institute of Electrical and Electronics Engineers), “IEEE Draft P802.3av / D3.4”, June 2009 ITU-T (International Telecommunication Union Telecommunication Standard Sector) SG15Q2 Intended type of document (R-C-TD): GR-4, “ONU power-saveP”

  In the system described in Non-Patent Document 1, ONU uplink transmission control is performed in units of logical links. For example, as one form of delay control and throughput control for uplink user data traffic of one ONU, the priority of uplink user data traffic and the logical link are linked by implementing a plurality of logical links for one ONU. Control according to.

  However, according to the conventional power saving method described in Non-Patent Document 2, the transition to the sleep mode is managed for each ONU. Therefore, when there are multiple logical links in one ONU, even if there is no transmission data temporarily in a certain logical link, if there is transmission data in other logical links installed in the ONU, it is possible to shift to the sleep mode. There was a problem that the power saving effect could not be expected because it was not possible.

  For example, when three logical links are implemented in one ONU, usually the three logical links perform uplink output control independently, and uplink user data is transmitted for each logical link according to an instruction from the OLT. . Here, even if there is no uplink user data on one logical link, when the remaining two logical links remain in the normal mode after entering the sleep mode, the remaining two logical links transmit uplink user data independently of each other. Keep doing.

  The ONU can shift to a sleep mode and stop a function unit (for example, an optical transmitter, etc.) related to uplink transmission in a time zone where there is no uplink allocation band for all logical links implemented by the ONU. However, when there are two logical links operating independently in the normal mode, the optical transmitter or the like cannot be stopped. Therefore, there is a problem that the power consumed by the ONU is high.

  As another additional problem, even if the ONU stops the optical transmitter or the like, the ONU can stop only during a time period in which no uplink transmission of the two logical links occurs. An optical transmitter or the like requires a preparation time before it can operate in the normal mode, and can actually stop only for a time shorter than a time during which no uplink transmission is performed. Therefore, there is a problem that the power saving effect cannot be expected.

  The present invention has been made in view of the above, and an object of the present invention is to obtain a communication system, a master station device, and a slave station device that can improve the power saving effect.

  In order to solve the above-described problems and achieve the object, the present invention is configured such that a master station device is connected to a plurality of slave station devices via a common communication path, and each slave station device is allocated within a band update period. A communication system that transmits data to the master station device using a determined bandwidth, wherein the slave station device includes a control unit that pauses some of the logical links, and a And an optical transmitter that transmits a bandwidth request necessary for data transmission using the logical link based on an instruction signal, and the master station device is configured so that the slave station device is based on a dormant state of the logical link. A cycle management unit that determines a bandwidth request cycle for transmitting a bandwidth request; and an optical transmitter that transmits an instruction signal instructing the transmission timing of the bandwidth request based on the bandwidth request cycle determined by the cycle management unit. It is characterized by.

  According to the present invention, it is possible to improve the power saving effect.

FIG. 1 is a diagram illustrating a configuration example of the PON system according to the first embodiment. FIG. 2 is a diagram illustrating an example of a bandwidth request reception period according to the first embodiment. FIG. 3 is a diagram illustrating an example of a bandwidth request reception period when returning from the sleep mode. FIG. 4 is a diagram illustrating an example of an activation request polling cycle when all logical links are in the sleep mode. FIG. 5 is a flowchart illustrating an example of bandwidth request reception cycle determination processing according to the first embodiment. FIG. 6 is a diagram illustrating an example of correspondence between service contents and individual setting periods. FIG. 7 is a diagram showing an example of mode management information when the logical link individual setting period is determined for each service content. FIG. 8 is a flowchart illustrating an example of a bandwidth request reception cycle determination process when the logical link individual setting cycle is determined based on the service content. FIG. 9 is a diagram for explaining the bandwidth allocation method according to the first embodiment. FIG. 10 is a diagram for explaining the effect of continuous assignment according to the first embodiment. FIG. 11 is a diagram showing an example of an allocation result by the conventional bandwidth allocation method and an allocation result by the bandwidth allocation method of the first embodiment. FIG. 12 is a diagram illustrating an example of an allocation result by the conventional bandwidth allocation method and an allocation result by the bandwidth allocation method of the first embodiment when all logical links are in the sleep mode. FIG. 13 is a diagram illustrating a configuration example of the PON system according to the second embodiment. FIG. 14 is a diagram illustrating an example of a bandwidth request transmission cycle according to the second embodiment. FIG. 15 is a diagram illustrating an example of a bandwidth request transmission cycle when returning from the sleep mode. FIG. 16 is a flowchart illustrating an example of bandwidth request transmission cycle determination processing according to the second embodiment. FIG. 17 is a diagram illustrating an example of a startup request polling cycle of the PON system according to the third embodiment. FIG. 18 is a diagram illustrating an example of an activation request polling cycle when all logical links are in the sleep mode. FIG. 19 is a diagram for explaining the power saving effect of the third embodiment. FIG. 20 is a diagram for explaining the power saving effect of the third embodiment when all logical links are in the sleep mode.

  Embodiments of a communication system, a master station device, and a slave station device according to the present invention will be described below in detail with reference to the drawings. Note that the present invention is not limited to the embodiments.

Embodiment 1 FIG.
FIG. 1 is a diagram showing a configuration example of a first embodiment of a PON system according to the present invention. In the present embodiment, a case where the communication system according to the present invention is configured as a PON system will be described as an example. As shown in FIG. 1, the PON system of this embodiment includes an OLT (master station device) 1, ONUs (slave station devices) 2-1 to 2-n (n is an integer of 1 or more), OLT1 and ONU2. -N connecting the optical fiber 3, the splitter 4 for branching the optical fiber for one-to-many connection, the higher-level communication device 5 connected to the upper level of the OLT 1, and the terminal communication device 6 connected under the ONU 2-1. It is equipped with. Although omitted in FIG. 1, it is assumed that the terminal communication devices are also connected under the control of ONU2-2 to ONU2-n.

  The OLT 1 according to the present embodiment multiplexes a downlink frame and PON control data, a downlink frame receiving unit 10 that receives downlink frames from the host communication device 5, a downlink frame buffer 11 that is a buffer for storing downlink frames, and the PON control data. A frame multiplexing unit 12, an optical transmitter 13 that transmits the multiplexed frame as an optical signal to each ONU, an optical receiver 16 that converts an optical signal received from the ONU into a reception frame (electrical signal), and a PON from the received frame A frame extraction unit 15 that extracts a control frame, an upstream frame transmission unit 14 that transmits a data frame to the higher-level communication device 5, a PON control unit 17 that allocates a bandwidth to each ONU based on the PON control frame, Individual setting cycle, which is the required value of bandwidth request cycle (band request transmission cycle) in normal mode for each link Comprising physical band update cycle management unit (the period management section) 18, a.

  As will be described later, the bandwidth update cycle management unit 18 is also a control unit that determines / controls the transmission cycle in which the ONU 2-1 transmits the report frame (bandwidth request) of each logical link according to the mode of each logical link. When a part of the logical links shifts to the sleep mode, the bandwidth update cycle management unit 18 controls the transmission cycle of the report frame longer than that before the shift under a predetermined condition. Therefore, the drive time of the optical transmitter 23 of the ONU 2-1 per unit time can be shortened, and a power saving effect can be obtained.

  Further, when different bandwidth request periods are set for each logical link in accordance with the service requirements assigned to each logical link (for example, 2 ms and 3 ms), when viewed as the entire ONU 2-1, the optical transmitter 23 is consequently obtained. Must be driven at intervals shorter than each band request cycle (for example, 1 ms). Even in such a case, the bandwidth update cycle management unit 18 adjusts the transmission cycle so that the transmission cycle becomes longer in an appropriate range, so that an effect of reducing power consumption can be obtained. This operation will also be described later.

  The ONU 2-1 of this embodiment includes an optical receiver 20 that converts a downstream optical signal received from the OLT 1 into a downstream frame (electrical signal), a frame extraction unit 21 that extracts a PON control frame from the downstream frame, and a subordinate Downlink frame transmission unit 22 that transmits data frames to terminal communication device 6, uplink frame reception unit 26 that receives uplink frames from terminal communication device 6, uplink frame buffer 25 that stores uplink frames, PON control frames, and terminals A frame multiplexing unit 24 that multiplexes upstream frames (data frames) from the optical transmitter 23, an optical transmitter 23 that transmits the multiplexed frames as optical signals to the OLT 1, and an upstream output based on the transmission time notified from the PON control unit 28. And a device control unit 27 that controls start and stop of the mechanism. Although the configuration of the ONU 2-1 has been described here, the ONUs 2-2 to 2-n have the same configuration as the ONU 2-1. Here, when there are a plurality of logical links, the PON control unit 28 can control to pause transmission of some logical links while continuing transmission of some logical links. By notifying the OLT 1 that the logical link has been suspended, there is a feature that a higher power saving effect can be obtained based on the logical link suspension state.

  Hereinafter, the operation of the present embodiment will be described. First, a normal communication operation between the OLT 1 and the ONUs 2-1 to 2-n will be described. In the ONUs 2-1 to 2-n, the upstream frame receiving unit 26 stores the upstream frames received from the terminal communication devices 6 under the respective upstream units in the upstream frame buffer 25. Based on the amount of data stored in the upstream frame buffer 25, the PON control unit 28 generates a Report frame (band request) that is a PON control frame that notifies the buffer amount and requests band allocation. The PON control unit 28 instructs the frame multiplexing unit 24 to transmit an uplink frame based on the content of the Gate frame that is a PON control frame that notifies the allocation band result received from the OLT 1. The frame multiplexing unit 24 multiplexes the upstream frame read from the upstream frame buffer 25 and the report frame generated by the PON control unit 28 and passes the multiplexed frame to the optical transmitter 23. The optical transmitter 23 converts the multiplexed frame into an optical signal and transmits it to the OLT 1.

  In the OLT 1, when the optical receiver 16 receives an optical signal in which a report frame is multiplexed from the ONUs 2-1 to 2-n, the optical receiver 16 converts the optical signal into an electric signal and passes it to the frame extraction unit 15 as a received frame. The frame extraction unit 15 extracts a Report report that is a PON control frame from the received frame and passes it to the PON control 17. The frame extraction unit 15 passes the data frame of the received frame to the upstream frame transmission unit 14. The upstream frame transmission unit 14 transmits the data frame received from the frame extraction unit 15 toward the higher-level communication device 5.

  The PON control unit 17 performs band allocation for each ONU based on the Report frame from each ONU, and generates an allocated band notification (Gate frame or transmission timing instruction signal) storing the allocation result. The bandwidth allocation result is notified as the data transmission start time and transmission time for each ONU. Further, the downlink frame transmission unit 10 stores the downlink frame received from the higher-level communication device 5 in the downlink frame buffer 11. The frame multiplexing unit 12 multiplexes the downlink frame read from the downlink frame buffer 11 and the Gate frame. Then, the optical transmitter 13 converts the multiplexed frame from an electrical signal to an optical signal and transmits it to the ONUs 2-1 to 2-n.

  In the ONUs 2-1 to 2-n, when the optical receiver 20 receives an optical signal including a Gate frame from the OLT 1, the optical receiver 20 converts the optical signal into an electric signal and passes it to the frame extraction unit 21 as a received frame. The frame extraction unit 21 extracts a Gate frame addressed to the own apparatus from the received frame and passes it to the PON control unit 28. Further, the frame extraction unit 21 passes the data frame addressed to itself from the received frame to the downlink frame transmission unit 22. The downlink frame transmission unit 22 transmits the data frame to the terminal communication device 6 under its control.

  Thereafter, as described above, the PON control unit 28 controls the transmission of the upstream frame based on the allocation result to the own apparatus designated by the Gate frame. Specifically, the PON control unit 28 instructs the frame multiplexing unit 24 to transmit data when the data transmission start time specified by the Gate frame is reached, and transmits data to the OLT 1. When the transmission time indicated by the Gate frame has elapsed since the start of data transmission, the frame multiplexing unit 24 is instructed to stop data transmission.

  In the above description of the normal operation, for simplification of explanation, the upstream transmission of the ONUs 2-1 to 2-n has been described as being performed with bandwidth allocation in units of ONU devices. However, in the present embodiment, bandwidth control for upstream transmission is performed. Is performed for each logical link in the ONU device. Therefore, when a plurality of logical links are mounted in one ONU, the above band control is performed independently for each logical link for the ONU. In other words, the ONU transmits a report frame independently for each logical link, and the OLT 1 generates and transmits a gate frame for each logical link to the ONU based on the report frame for each logical link. Then, the ONU transmits an upstream frame for each logical ring based on the Gate frame. The ONU stores the upstream frame in the upstream frame buffer 25 for each logical link.

  Further, in this embodiment, for power saving, the ONUs 2-1 to 2-n have their constituent elements related to uplink transmission (the optical transmitter 23, frame multiplexing) in a time zone in which uplink transmission from the own device does not occur. Part of the function of the unit 24) is stopped. Specifically, the PON control unit 28 notifies the device control unit 27 of a transmission time zone, which is a time zone in which uplink transmission from the own device occurs, based on the allocation result from the OLT 1. The device control unit 27 stops each device related to uplink transmission such as the optical transmitter 23 during a period when uplink transmission is not performed from the own apparatus based on the notified transmission time zone.

  On the other hand, in order to save the power of the ONU, a technique for transitioning the ONU to the sleep mode when there is no data to be transmitted has been studied by ITU-T and the like. In the present embodiment, in each ONU, the PON control unit 28 holds and manages the current mode (Sleep mode or normal mode) as mode information for each logical link mounted on itself.

  For example, the PON control unit 28 checks the amount of data stored in the upstream frame buffer 25 for each logical link, and determines that a logical link having no stored data should be shifted to the sleep mode (sleep state). Then, a sleep mode transition process is started in order to transition to the sleep mode. Note that even if the logical link shifts to the sleep mode, the link is not broken in principle, but only a temporary communication is not performed.

  As the sleep mode transition process, the PON control unit 28 first generates a sleep request for a logical link (Sleep transition target logical link) to be shifted to the sleep mode as a PON control frame, and passes through the frame multiplexing unit 24 and the optical transmitter 23. Send to OLT1. When the PON control unit 28 receives the PON control frame indicating the sleep instruction corresponding to the sleep request from the OLT via the optical receiver 20 and the frame extraction unit 21, the mode information is set so that the sleep transition target logical link is set to the sleep mode. Update.

  In the OLT 1, when the PON control unit 17 receives a sleep request from the ONUs 2-1 to 2-n via the optical receiver 16 and the frame extraction unit 15, a sleep instruction that allows the requested logical link to transition to the sleep mode. PON control frames are generated and notified to the ONUs 2-1 to 2-n via the frame multiplexing unit 12 and the optical transmitter 13.

  In addition, when the upstream frame is accumulated in the upstream frame buffer 25 for the logical link that has been in the sleep mode, the PON control unit 28 of the ONU 2-1 issues a startup request for returning (starting up) the logical link from the sleep mode. Generate as a frame. Then, the generated activation request is transmitted to the OLT 1. In the OLT 1, when receiving the activation request, the PON control unit 17 generates an activation instruction for permitting activation of the requested logical link as a PON control frame and transmits it to the ONU 2-1. By the operation as described above, the ONUs 2-1 to 2-n and the OLT 1 perform mode (normal mode, sleep mode) transition for each logical link.

  Next, the bandwidth request method of this embodiment will be described. In the conventional PON system, when bandwidth allocation is performed for each logical link, the OLT periodically transmits a Gate frame notifying bandwidth allocation for each logical link, and the ONU is based on the Gate frame for each logical link. A frame obtained by multiplexing the Report frame and the data frame is transmitted. In the OLT, the transmission interval of the Gate frame is set as a bandwidth allocation cycle, and the allocation result of the bandwidth allocation cycle next to the bandwidth allocation cycle in which the Gate frame is transmitted is notified. This bandwidth allocation cycle is a constant value that does not depend on the ONU or the logical link in the conventional PON system.

  On the other hand, in this embodiment, the transmission period of the Gate frame is determined based on the mode of the logical link. Each ONU receives a Gate frame and transmits a Report frame for requesting a bandwidth in the next bandwidth allocation period. Since the transmission permission of the Report frame is also given by the Gate frame, the transmission cycle of the Gate frame determines the transmission cycle of the Report frame. That is, by changing the transmission period of the Gate frame, the period for receiving the bandwidth request from each ONU can be changed. In the present embodiment, a cycle for receiving a bandwidth request from each ONU is referred to as a bandwidth request reception cycle.

  Next, a method for determining the bandwidth request reception cycle will be described. First, in the present embodiment, it is assumed that an individual setting period is previously determined for each logical link of each ONU, and the bandwidth update period management unit 18 of the OLT 1 holds the information. The method for determining the individual setting cycle will be described later. Moreover, you may make it update an individual setting period as needed.

  FIG. 2 is a diagram illustrating an example of a bandwidth request reception cycle according to the present embodiment. In this example, it is assumed that the ONU 2-1 has three logical links from LLID (Logical Link IDentifier) # 1 to LLID # 3. As shown in the lower part of FIG. 2, the individual setting cycle of LLID # 1 is set to 3 ms, the individual setting cycle of LLID # 2 is set to 2 ms, and the individual setting cycle of LLID # 3 is set to 1 ms. To do. In the initial state, it is assumed that all three logical links are in the normal mode. The PON control unit 17 holds information about the individual setting period for each logical link and the mode for each logical link (whether the mode is the normal mode or the sleep mode), and when the mode of each logical link is changed. The bandwidth update cycle management unit 18 is notified. The bandwidth update cycle management unit 18 holds the notified mode for each logical link.

  Note that the OLT 1 also periodically allocates a transmission band for accepting an activation request for a logical link in the sleep mode, and periodically transmits a Gate frame that notifies the allocation. Here, the ONU 2-1 shows an example in which three logical links are mounted, but the number of logical links mounted by one ONU is not limited to this, and any number may be used.

  As shown in FIG. 2, when all the logical links mounted on the ONU 2-1 are in the normal mode, the bandwidth update cycle management unit 18 of the OLT 1 sets the individual setting cycle set for these logical links. Is determined as the bandwidth request reception cycle. Then, bandwidth allocation for each logical link of the ONU 2-1 is performed for each bandwidth request reception cycle, and a Gate frame is transmitted for each bandwidth request reception cycle. Similarly, for the ONUs 2-2 to 2-n, the bandwidth update cycle management unit 18 also sets the minimum value of the individual setting cycle set for each mounted logical link (1 ms in this example). Is determined as a bandwidth request reception cycle.

  When the ONU 2-1 receives the Gate frame, the ONU 2-1 transmits the uplink frame and the Repot frame based on the allocation result notified by the Gate frame as described above. That is, in the present embodiment, the period at which the OLT 1 receives a bandwidth allocation request from the ONU 2-1 is determined by the period at which the OLT 1 transmits a Gate frame that permits the transmission time zone of the Report frame (or the Report frame and the data frame) It will be. In the OLT 1, when a report frame that is a bandwidth request is received, a bandwidth is allocated to the ONU 2-1. Therefore, the longer the bandwidth request reception cycle is, the fewer the transmission opportunities of the ONU 2-1.

  Then, as shown in FIG. 2, it is assumed that a Sleep request is transmitted for LLID # 3 of the ONU 2-1 and the LLID # 3 transitions to the Sleep mode. The PON control unit 17 changes the LLID # 3 mode information of the ONU 2-1 held based on the Sleep request to the Sleep mode, and notifies the bandwidth update cycle management unit 18 of the change. The bandwidth update cycle management unit 18 changes the bandwidth request reception cycle for the ONU 2-1 to the minimum value among the individual setting cycles of the logical links (LLID # 1 and LLID # 2) excluding the LLID # 3 which is the sleep mode. To do. Then, for the LLID # 3 of the ONU 2-1, the PON control unit 17 sets a cycle for accepting transmission of a startup request (hereinafter referred to as a startup request polling cycle (startup request inquiry cycle)) to an individual setting cycle of LLID # 3 (this In the example, it is set as 1 ms). A Gate frame for accepting an activation request for LLID # 3 is transmitted at an activation request polling cycle.

  FIG. 3 is a diagram illustrating an example of a bandwidth request reception period when returning from the sleep mode. As described with reference to FIG. 2, it is assumed that LLID # 3 transitions to the sleep mode and LLID # 1 and LLID # 2 are in the normal mode. In this state, it is assumed that an activation request for LLID # 3 is transmitted from ONU 2-1 and LLID # 3 returns to the normal mode. In this case, for the ONU 2-1, the three logical links are in the normal mode as in the first state of FIG. 2. Therefore, similarly to the initial state of FIG. 2, the minimum value of the individual setting period set in the mounted logical link (1 ms in this example) is determined as the band request reception period.

  FIG. 4 is a diagram illustrating an example of an activation request polling cycle when all logical links are in the sleep mode. In the example of FIG. 4, it is assumed that all three mounted on the ONU 2-1 have transitioned to the sleep mode. In this case, the individual setting cycle of each logical link is set as a startup request polling cycle, and the OLT 1 transmits a Gate frame for receiving a startup request for each logical link at the startup request polling cycle.

  FIG. 5 is a flowchart illustrating an example of the bandwidth request reception cycle determination process according to the present embodiment. When a transition from the sleep mode to the normal mode or a transition from the normal mode to the sleep mode occurs for any logical link, the bandwidth update cycle management unit 18 sets the bandwidth request reception cycle for the ONU including the logical link. Perform decision processing. Further, the band update cycle management unit 18 notifies the PON control unit 17 of the determined band request reception cycle. As shown in FIG. 5, first, the bandwidth request reception cycle and logical link No. for the ONU for which the bandwidth request reception cycle is determined are initialized (step S10). Specifically, the bandwidth request reception cycle is set to a numerical value (for example, 9999) larger than the maximum value of the assumed bandwidth request reception cycle, and the logical link No is set to the minimum value associated with the logical link (this example) In this case, 0 is the minimum value).

  It is determined whether the logical link (the logical link corresponding to the set logical link No) is in the normal mode (step S11). When the logical link is in the normal mode (step S11 Yes), it is determined whether or not the individual setting cycle of the logical link is smaller than the bandwidth request reception cycle (step S12).

  When the individual setting cycle of the logical link is smaller than the bandwidth request reception cycle (Yes in step S12), the bandwidth request reception cycle is set as the individual setting cycle of the logical link (step S13). Then, it is determined whether or not the examination of all logical links (the processing of step S11 to step S13) has been completed (step S14). If not completed (No in step S14), the next logical link No is set (logical The link number is incremented: Step S15), and the process returns to Step S11.

  If it is determined in step S11 that the link is not in the normal mode (No in step S11), the process proceeds to step S14. If the individual setting period of the logical link is not smaller than the bandwidth request reception period in step S12 (No in step S12), the process proceeds to step S14. If it is determined in step S14 that the examination of all logical links has been completed (Yes in step S14), the bandwidth request reception cycle determination process is terminated.

  Here, a method for determining the individual setting period for each logical link will be described. There are various methods for determining the individual setting period for each logical link. First, a method for determining based on the service contents will be described. FIG. 6 is a diagram illustrating an example of correspondence between service contents and individual setting periods. Since the individual setting period corresponds to the allocation period, generally, a service with a higher real-time requirement has a shorter value. Therefore, for example, a telephone service with a high real-time requirement is set to a short individual setting cycle of 1 ms, and a service with a low real-time requirement such as an Internet service is set to a long individual setting cycle of 3 ms. Note that FIG. 6 is an example, and the individual setting period for each service and the service classification for determining the individual setting period are not limited to this, and may be set in any manner.

  FIG. 7 is a diagram showing an example of mode management information when the logical link individual setting period is determined for each service content. When the individual setting cycle is determined based on the service content, the individual setting cycle for each logical link can be obtained by holding the information as shown in FIG. 6 and the service content for each logical link. In FIG. 7, in addition to the service contents for each logical link, the mode for each logical link is managed simultaneously. By holding the information shown in FIG. 6 and the information shown in FIG. 7 in the bandwidth update cycle management unit 18 of the OLT 1, the bandwidth request reception cycle described above can be determined.

  Next, a method for determining the individual setting period based on the maximum bandwidth for each logical link will be described. First, the OLT 1 sets the most basic bandwidth allocation interval BG common to all logical links. BG is a value corresponding to the minimum value of the bandwidth allocation period, and for example, a numerical value corresponding to a conventional bandwidth allocation period, a minimum value of an assumed individual setting period, or the like is set.

Then, the individual setting cycle GC of each logical link is calculated based on the following equation (1) using the maximum bandwidth (maximum transmission rate) MaxBW set for each logical link. “Round up ()” means that the remainder of the division result in () is rounded up. The line speed is the line speed between the OLT 1 and the ONUs 2-1 to 2-n.
GC = round-up (line speed ÷ MaxBW) x BG (1)

A calculation example assuming specific numerical values is shown below. When BG = 0.5 ms, line speed = 10 Gbps, and MaxBW = 1.5 Gbps, the following equation (2) is obtained.
GC = rounded up (10 Gbps ÷ 1.5 Gbps) × 0.5 ms
= 7 x 0.5 ms = 3.5 ms (2)

  In addition, said Formula (1) is an example, and you may calculate an individual setting period by calculation methods other than Formula (1) using a maximum zone | band.

Further, the individual setting period may be determined based on the minimum bandwidth for each logical link. In this case, MaxBW in Expression (1) is replaced with the minimum band MinBw, and calculation is performed using Expression (3) below.
GC = round-up (line speed ÷ MinBW) x BG (3)

  The method for determining the individual setting period described above is an example, and the individual setting period may be determined by a method other than this. Further, it may be determined by combining two or more of the above-described three types of individual setting period determination methods. For example, the above BG may be determined for each service and calculated according to the equation (1).

  Note that the individual setting period is determined here by the OLT 1 (for example, the PON control unit 17). However, the present invention is not limited to this, and the ONUs 2-1 to 2-n determine the individual setting period for each logical link. You may make it notify to OLT1 from ONU2-1 to 2-n.

  FIG. 8 is a flowchart illustrating an example of a bandwidth request reception cycle determination process when the logical link individual setting cycle is determined based on the service content. When the logical link individual setting period is determined based on the service contents, the bandwidth request reception period may be obtained by the procedure shown in FIG. 8 instead of FIG. A different point of the example of FIG. 5 in the procedure shown in FIG. 8 will be described.

  In the example shown in FIG. 8, it is assumed that the PON control unit 17 holds the information shown in FIGS. Steps S10 and S11 are the same as in the example of FIG. Instead of step S12, as step S16, it is determined whether or not the individual setting period corresponding to the service content of the logical link is smaller than the bandwidth request reception period (step S16).

  If it is determined that the individual setting cycle corresponding to the service content of the logical link is smaller than the bandwidth request reception cycle (Yes in step S16), the bandwidth request reception cycle is set to the individual setting cycle corresponding to the service content of the logical link ( Step S17). If it is determined that the individual setting period corresponding to the service content of the logical link is not smaller than the bandwidth request reception period (No in step S16), the process proceeds to step S14. Steps S14 and S15 are the same as in the example of FIG.

  In the conventional PON system, since the frequency of performing bandwidth allocation is constant regardless of the logical link, the allocation cycle is determined corresponding to the logical link that requires the shortest bandwidth allocation cycle among the ONUs, and Gate Send a frame. For example, band allocation is performed at a period of 1 ms corresponding to the minimum value of the individual setting period shown in FIG. On the other hand, in the ONUs 2-1 to 2-n, as described above, the device control unit 27 stops the constituent elements related to uplink transmission in a time zone in which there is no uplink transmission. Then, the device control unit 27 activates components related to uplink transmission before the start of uplink transmission. A certain amount of preparation time is required to activate the component related to uplink transmission, and if the period of bandwidth allocation is short, the component related to uplink transmission may not be stopped. Even if it can be stopped, it takes a short time.

  On the other hand, in the present embodiment, an individual setting cycle is defined for each logical link, and the minimum value of the individual setting cycle of the logical link in the normal mode is set as a bandwidth request reception cycle. Therefore, when the logical link having the shortest individual setting period is in the sleep mode, the period for performing bandwidth allocation can be lengthened, and the time for transmitting data and the time for not transmitting data are longer than in the prior art. Become. In addition, preparation time for activation can be reduced. Therefore, it is possible to lengthen the stop time of the constituent elements related to uplink transmission, and to further save power.

  Further, in the present embodiment, the PON control unit 17 of the OLT 1 allocates bandwidth allocation time zones for logical links implemented by one ONU as continuous time zones as follows. By performing such allocation, it is possible to further increase the stop time of the constituent elements related to uplink transmission.

  Hereinafter, the bandwidth allocation method of the present embodiment will be described. FIG. 9 is a diagram for explaining the bandwidth allocation method of the present embodiment. As shown in FIG. 9, the PON control unit 17 of the OLT 1 allocates bandwidths to a plurality of logical links in one ONU so that uplink transmission time zones corresponding to those logical links are continuous.

  In the example of FIG. 9, three logical links LLID # 1 to LLID # 3 in the ONU 2-1 request allocation, and three logical links LLID # 4 to LLID # 6 in the ONU 2-2 request allocation. Suppose you are. In that case, the OLT 1 assigns the uplink transmission time zones of the logical links (LLID # 1 to LLID # 3) in the ONU 2-1 as continuous transmission time zones, and after the uplink transmission time zone of the logical links in the ONU 2-1. The uplink transmission time zones of the logical links (LLID # 4 to LLID # 6) in the ONU 2-2 are assigned as continuous transmission time zones. When the uplink transmission time zones of logical links in one ONU are made continuous in this way (continuous allocation is performed), each ONU can secure a long time zone during which no transmission occurs, thereby further saving power.

  When there is a sleep mode logical link among the logical links in one ONU, a sleep mode logical link start request is transmitted so as to be continuous with the transmission time zone assigned to the ONU normal mode logical link. Allocate a trusted transmission time zone.

  FIG. 10 is a diagram for explaining the effect of continuous allocation according to the present embodiment. As shown in the upper part of FIG. 10, in the conventional PON system, the transmission time zone of the logical link of 1 ONU is not assigned so as to be continuous. Therefore, the period during which uplink transmission is not performed is short. On the other hand, as shown in the lower part, in this embodiment, the transmission time zone of the logical link of 1 ONU is continuous, so that the period during which uplink transmission is not performed is long. Therefore, it is possible to lengthen the time for stopping the components related to uplink transmission.

  11 and 12 compare the allocation using the conventional bandwidth request reception cycle and the allocation using the bandwidth request reception cycle of the present embodiment when the uplink transmission time zones of the logical link of 1 ONU are made continuous. FIG. In FIG. 11, when the ONU implements three logical links from LLID # 1 to LLID # 3 and LLID # 3 is in the sleep mode, the allocation result by the conventional bandwidth allocation method and the present embodiment An example of the allocation result by the bandwidth allocation method is shown. In the figure, rectangles with numerical values of 1, 2, and 3 indicate transmission time zones of LLID # 1, LLID # 2, and LLID # 3, respectively. In addition, the filled rectangle is a transmission time zone for an activation request for the logical link (LLID # 3) in the sleep mode.

  As shown in the upper part of FIG. 11, conventionally, transmission time zones are assigned to all logical links in both the sleep mode and the normal mode for each fixed bandwidth assignment period. Therefore, the ONU can completely stop the uplink transmission from the time when the transmission time zone of the last logical link (LLID # 3 in the example of FIG. 11) within the bandwidth request reception cycle is completed. This is until the transmission time period of the first logical link in the cycle (LLID # 1 in the example of FIG. 11) starts. In contrast, in this embodiment, when LLID # 3 is in the sleep mode, the allocation request reception cycle is doubled as shown in the lower row (the individual setting cycle of each LLID is the same as that shown in FIG. Similarly, it is possible to lengthen the time for stopping ONU uplink transmission.

  Also, as shown in FIG. 11, in this embodiment, the transmission time zone for the activation request for the sleep mode logical link (LLID # 3) is continuous with the transmission time zone of the normal mode logical link. The transmission time zone is assigned so as to be at the end (right end, ie, the end in the example of FIG. 11). In this example, the transmission time zone for the sleep mode logical link activation request is assigned to the end of the continuous transmission time zone. However, the transmission time zone is not limited to this, and transmission for the sleep mode logical link activation request is performed. A time zone may be assigned to be the first of consecutive transmission time zones. If there are a plurality of Sleep mode logical links, they may be assigned first and last, or may be assigned in order from the first or last.

  FIG. 12 shows a case where all logical links of the ONU are in the sleep mode. The individual setting period of each LLID is the same as the example shown in FIG. As shown in the upper part of FIG. 12, in the past, a transmission time zone for receiving an activation request for all the logical links in the sleep mode is assigned for each fixed bandwidth assignment period. On the other hand, in the present embodiment, the transmission time zone of the activation request is assigned at the individual setting cycle corresponding to each logical link. Therefore, the bandwidth can be effectively used.

  In the present embodiment, the allocation (continuous allocation) is performed in which the upstream transmission time zone of 1 ONU is a continuous transmission time zone, and the allocation cycle is controlled using the above-described bandwidth request reception cycle. Only one of continuous allocation and allocation cycle control may be implemented.

  In this embodiment, the PON system has been described as an example. However, the master station device allocates an upstream band for each logical link to the slave station device, and the master station device transmits the slave station device to the slave station device at a predetermined cycle. The operation of the present embodiment is applied not only to the PON system but also to other communication systems as long as it is a communication system that grants permission and receives a bandwidth allocation request from a slave station device during the transmission permission time zone. May be. In that case, the PON control units 17 and 28 serve as communication control means for allocating an upstream band for each logical link of the slave station device.

  As described above, in the present embodiment, the OLT 1 sets the individual setting period for each logical link for the ONUs 2-1 to 2-n, and among the individual setting periods of the logical link in the normal mode for each ONU. The gate frame is transmitted with the minimum period of allocating the bandwidth, and for the sleep mode logical link, the gate frame for receiving the activation request is transmitted with the individual setting period of the logical link. Therefore, it is possible to reduce the upstream transmission triggers of the ONUs 2-1 to 2-n, secure a longer time for stopping the upstream transmission, and improve the power saving effect compared to the conventional case. In addition, regarding the sleep mode logical link, since the Gate frame for receiving the activation request is transmitted in the individual setting period of the logical link, it is possible to prevent the activation request from being delayed.

  Furthermore, in this embodiment, the OLT 1 assigns the uplink transmission time zone for the logical link of 1 ONU so as to be a continuous time zone at the time of bandwidth allocation. Therefore, it is possible to secure a longer time for stopping the uplink transmission and improve the power saving effect.

Embodiment 2. FIG.
FIG. 13 is a diagram showing a configuration example of the second embodiment of the PON system according to the present invention. The PON system of the present embodiment is the same as the PON system of the first embodiment except that the OLT 1 of the first embodiment is replaced with the OLT 1a and the ONUs 2-1 to 2-n are replaced with the ONUs 2a-1 to ONU2a-n. . The OLT 1a according to the present embodiment is the same as the OLT 1 according to the first embodiment, except that the bandwidth update period management unit 18 is deleted from the OLT 1 according to the first embodiment. The ONU 2a-1 of the present embodiment is the same as the ONU 2a-1 of the first embodiment, except that the bandwidth update period management unit 29 is added to the ONU 2-1 of the first embodiment.

  In the first embodiment, a bandwidth request reception is performed as a cycle (band request cycle) in which the bandwidth update cycle management unit 18 of the OLT 1 makes a bandwidth request based on the individual setting cycle determined for each logical link and the mode for each logical link. The cycle was set. In the present embodiment, the ONUs 2a-1 to 2a-n determine the period for performing band allocation by controlling the period (band request transmission period) for transmitting the Report frame as the band request period. Components having the same functions as those of the first embodiment are denoted by the same reference numerals as those of the first embodiment, and description thereof is omitted.

  In both Embodiment 1 and Embodiment 2, the period for performing bandwidth allocation is controlled by controlling the period for performing bandwidth request (band request period). In the first embodiment, the OLT 1 side receives a report frame (band request) as the band request cycle (band request reception cycle). In this embodiment, the ONUs 2a-1 to 2a-n transmit report frames. A period (band request transmission period) is used.

  The method for determining the individual setting period for each logical link in the present embodiment is the same as in the first embodiment. In the present embodiment, the OLT 1a determines the individual setting period for each logical link (for example, the PON control unit 17 of the OLT 1a) and notifies the ONUs 2a-1 to 2a-n. However, the present invention is not limited to this, and the ONUs 2a-1 to 2a-n may determine the individual setting period for the logical links in the own apparatus.

  FIG. 14 is a diagram illustrating an example of a bandwidth request transmission cycle according to the present embodiment. In FIG. 14, as in the example of FIG. 2 of the first embodiment, it is assumed that the ONU 2a-1 has three logical links LLID # 1 to LLID # 3, and the individual setting cycle of LLID # 1 is 3 ms. Assume that the individual setting cycle of LLID # 2 is set to 2 ms, and the individual setting cycle of LLID # 3 is set to 1 ms. In the example of FIG. 14, it is assumed that the three logical links are initially in the normal mode. Note that the method of transitioning to the sleep mode and returning to the normal mode of the present embodiment is the same as that of the first embodiment.

  When the three logical links are in the normal mode, the bandwidth update cycle management unit 29 of the ONU 2a-1 determines the minimum value among the individual setting cycles corresponding to LLID # 1 to LLID # 3 as the bandwidth transmission request cycle, Notify the PON control unit 28. The PON control unit 28 transmits a Report frame at a band transmission request cycle. Note that the OLT 1 transmits a Gate frame including an allocation result for an uplink frame and a Reprot frame (or only a Report frame) at a constant cycle (here, 1 ms). In other words, the OLT 1 permits the ONUs 2a-1 to 2a-n to transmit the Repot frame at a constant period. The cycle in which the OLT 1 transmits the Gate frame is set to a cycle equal to or less than the minimum value of the assumed individual setting cycle.

  In the example of FIG. 14, initially, the transmission cycle of the Gate frame and the transmission cycle of the Report frame (band request transmission cycle) match, so the ONU 2a-1 transmits a Report frame every time the Gate frame is received. Become.

  Then, it is assumed that the logical link of LLID # 3 transits to the sleep mode in the middle. The PON control unit 28 notifies the band update period management unit 29 that the logical link of LLID # 3 has transitioned to the sleep mode. The bandwidth update cycle management unit 29 sets the bandwidth transmission request cycle (Report frame transmission cycle) to the minimum value (see FIG. 14) of the individual setting cycles of the logical link (LLID # 1 and LLID # 2 in the example of FIG. 14). In the example of 14, 2 ms) is determined and notified to the PON control unit 28. Thereafter, the ONU 2a-1 transmits a report frame every 2 ms, and transmits a report frame once every two receptions of the gate frame.

  FIG. 15 is a diagram illustrating an example of a bandwidth request transmission cycle when returning from the sleep mode. As illustrated in FIG. 15, when LLID # 3 that has transitioned to the sleep mode returns to the normal mode, the band update period management unit 29 sets the minimum value among the individual set periods of LLID # 1 to LLID # 3 to the band. It is determined as the request transmission cycle.

  When receiving the Report frame, the OLT 1a allocates a transmission band to the transmission source ONU, and notifies the transmission result to the transmission source ONU using the Gate frame. Since the transmission frequency of the report frame decreases, the time zone that the OLT 1a does not allocate to the uplink transmission of the logical link of the ONU increases. Therefore, the ONU can improve the power saving effect.

  Similarly to the first embodiment, when the PON control unit 17 of the OLT 1a performs the allocation so that the transmission time zone of the logical link of the 1ONU is continuous, the power saving effect of the ONUs 2a-1 to 2a-n is further increased. Can be increased.

  FIG. 16 is a flowchart illustrating an example of bandwidth request transmission cycle determination processing according to the present embodiment. The bandwidth update cycle management unit 29 performs bandwidth request transmission cycle determination processing when a transition from the sleep mode to the normal mode or a transition from the normal mode to the sleep mode occurs for any logical link of the own device. To do. Further, the band update cycle management unit 29 notifies the PON control unit 28 of the determined band request reception cycle. As shown in FIG. 16, first, the bandwidth request transmission cycle and logical link No. for the ONU for which the bandwidth request transmission cycle is determined are initialized (step S20). Specifically, the bandwidth request transmission cycle is set to a numerical value (for example, 9999) larger than the maximum value of the assumed bandwidth request reception cycle, and the logical link number is set to the minimum value of the number associated with the logical link (this example) In this case, 0 is the minimum value).

  It is determined whether the logical link (the logical link corresponding to the set logical link No) is in the normal mode (step S21). When the logical link is in the normal mode (step S21 Yes), it is determined whether or not the individual setting cycle of the logical link is smaller than the bandwidth request transmission cycle (step S22).

  If the individual setting cycle of the logical link is smaller than the bandwidth request transmission cycle (Yes in step S22), the bandwidth request transmission cycle is set as the individual setting cycle of the logical link (step S23). Then, it is determined whether or not the detailed examination of all logical links (steps S21 to S23) has been completed (step S24), and if not completed (No in step S24), the next logical link No is set (logical The link No is incremented: Step S25), and the process returns to Step S21.

  If it is determined in step S21 that the link is not in the normal mode (No in step S21), the process proceeds to step S24. If the individual setting period of the logical link is not smaller than the bandwidth request transmission period in step S22 (No in step S22), the process proceeds to step S24. If it is determined in step S24 that the examination of all the logical links has been completed (Yes in step S24), the bandwidth request transmission cycle determination process is terminated.

  As described above, in this embodiment, the individual setting period is set for each logical link, and the bandwidth update period management unit 29 of the ONU 2a-1 sets the report frame at the minimum individual setting period of the logical links in the normal mode. I sent it. Further, the OLT 1a transmits a Gate frame at a predetermined cycle. Therefore, it is possible to reduce the uplink transmission trigger of the ONUs 2a-1 to 2a-n, to secure a long time for stopping the uplink transmission, and to improve the power saving effect as compared with the conventional case. In addition, since the transmission time zone for transmitting the activation request for the logical link in the sleep mode is also a time zone that is continuous with the transmission time zone in the normal mode, the ONUs 2a-1 to 2a-n have a time to stop the uplink transmission. It can be secured longer.

Embodiment 3 FIG.
FIG. 17 is a diagram illustrating an example of a startup request polling period according to the third embodiment of the PON system according to the present invention. The configuration of the PON system of the present embodiment is the same as the configuration of the PON system of the first embodiment. The configurations of the OLT and ONU of the present embodiment are the same as the configurations of the OLT 1 and ONU 2-1 of the first embodiment, respectively.

  In the first embodiment, the OLT 1 determines the bandwidth request reception period based on the individual setting period of the logical link in the normal mode of one ONU, thereby reducing the upstream transmission trigger of the ONU. In the present embodiment, the bandwidth request reception cycle is determined in the same manner as in the first embodiment, but the activation request polling cycle determination method for the sleep mode logical link is different from that in the first embodiment. Further, the ONU upstream transmission opportunity is reduced. Hereinafter, differences from the first embodiment will be described.

  In the example of FIG. 17, it is assumed that the ONU 2-1 having the same configuration as that of the first embodiment is mounted with three logical links LLID # 1 to LLID # 3. Further, the individual setting period of each logical link is the same as that in the example of FIG. In the initial state, all three logical links are in the normal mode, and the method for determining the bandwidth request reception period in this state is the same as in the first embodiment.

  Next, it is assumed that the logical link of LLID # 3 transits to the sleep mode on the way. The method for determining the bandwidth request reception period at this time is the same as that in the first embodiment. On the other hand, in the present embodiment, the bandwidth update cycle management unit 18 of the OLT 1 determines the activation request polling cycle of LLID # 3 as the same value as the bandwidth request reception cycle determined at that time. That is, in the example of FIG. 17, when the logical link of LLID # 3 transitions to the sleep mode, the minimum value (2 ms in this example) of the individual setting periods of LLID # 1 and LLID # 2 is set as the bandwidth request reception period. However, the activation request polling cycle of LLID # 3 is also set to the same value as the bandwidth request reception cycle.

  FIG. 18 is a diagram illustrating an example of an activation request polling cycle when all logical links are in the sleep mode. In FIG. 18, it is assumed that three logical links of LLID # 3 are mounted as in FIG. 17, and all of the three logical links have transitioned to the sleep mode. In this case, the bandwidth update cycle management unit 18 of the OLT 1 sets the maximum value (3 ms in this example) among the individual setting cycles of LLID # 1 to LLID # 3 as the activation request polling cycle. The operations of the present embodiment other than those described above are the same as those of the first embodiment.

  FIG. 19 is a diagram for explaining the power saving effect of the present embodiment. In the example of FIG. 19, it is assumed that LLID # 3 is in the sleep mode and LLID # 1 and LLID # 2 are in the normal mode among the three logical links LLID # 1 to LLID # 3. In the conventional PON system, as shown in the upper part, a transmission time zone is assigned to all logical links every fixed bandwidth allocation cycle. On the other hand, in this embodiment, the minimum value of the individual setting period of the logical link in the normal mode is set as the bandwidth request reception period for all logical links, and the transmission time zone is set for all logical links in the bandwidth request reception period. Assign. Therefore, since the data transmission timing can be summarized, it is possible to secure a long time during which the uplink transmission of the ONU is not performed. In addition, as shown in FIG. 19, when the bandwidth request reception cycle is longer than the conventional bandwidth allocation cycle, the bandwidth is not allocated to the ONU (in FIG. 19, the bandwidth allocation cycle in which the bandwidth is described as being available effectively). ) Can be used for allocation to other ONUs, and the bandwidth can be used effectively.

  FIG. 20 is a diagram for explaining the power saving effect of the present embodiment when all logical links are in the sleep mode. In the conventional PON system, as shown in the upper part, a transmission time zone is assigned to all logical links every fixed bandwidth assignment period. In this embodiment, as shown in the lower part, all logical links are in sleep mode. In this case, the maximum value among the individual setting periods of LLID # 1 to LLID # 3 is set as an activation request polling period, and a transmission time zone is allocated to all logical links in the activation request polling period. Therefore, it is possible to further increase the time during which ONU uplink transmission is not performed. Further, the bandwidth of the activation request bandwidth can be allocated to other ONUs, and the bandwidth can be used effectively.

  As described above, in this embodiment, the OLT 1 determines the bandwidth request reception cycle in the same manner as in the first embodiment, and when there are logical links of the normal mode and the sleep mode among the logical links of one ONU. The activation request polling cycle for the sleep mode logical link is made the same as the bandwidth request reception cycle for the normal mode logical link. When all logical links of one ONU are in the sleep mode, the maximum value among the individual setting periods of each logical link is set as the activation request polling period. Therefore, it is possible to further increase the time during which ONU uplink transmission is not performed as compared with Embodiment 1, and to improve the power saving effect. Further, the bandwidth of the activation request bandwidth can be allocated to other ONUs, and the bandwidth can be used effectively.

  As described above, the communication system, the master station device, and the slave station device according to the present invention are useful for a PON system in which the master station device allocates a bandwidth to the slave station device in a time division manner. This is suitable for a PON system in which the upstream transmission function is stopped in a time zone during which no transmission is performed.

1,1a OLT
2-1 to 2-n, 2a-1 to 2a-n ONU
3 Optical fiber 4 Splitter 5 Host communication device 6 Terminal communication device 10 Downstream frame reception unit 11 Downstream frame buffer 12, 24 Frame multiplexing unit 13, 23 Optical transmitter 14 Upstream frame transmission unit 15, 21 Frame extraction unit 16, 20 Optical reception Device 17, 28 PON control unit 18, 29 Band update cycle management unit 22 Down frame transmission unit 25 Up frame buffer 26 Up frame reception unit 27 Device control unit

Claims (23)

A communication system in which a master station device is connected to a plurality of slave station devices via a common communication path, and each slave station device transmits data to the master station device using a band allocated within a bandwidth update period. And
The slave station device is
A controller that pauses some of the plurality of logical links;
An optical transmitter for transmitting a bandwidth request necessary for data transmission using the logical link based on an instruction signal from the master station device,
The master station device is
A period management unit for determining a bandwidth request period for transmitting a bandwidth request by the slave station device based on a dormant state of the logical link;
An optical transmitter that transmits an instruction signal instructing a transmission timing of the bandwidth request based on a bandwidth request cycle determined by the cycle management unit;
A communication system comprising:   2. The cycle management unit of the master station device changes a transmission cycle of the bandwidth request of a slave station device in which a part of logical links are in a dormant state to a cycle longer than that before the pause. Communication system.   The cycle management unit of the master station device sets the bandwidth request cycle even when some of the logical links are in the dormant state and the request values of the bandwidth request cycles between the plurality of logical links in the continuous state do not match. The communication system according to claim 2, wherein the communication value is matched with any one of the request values. The slave station device is
For each logical link, it is determined whether transmission is stopped or transmission is continued, the determination result is notified to the master station apparatus, and uplink transmission is performed based on the allocation result received from the master station apparatus Slave station communication control unit that determines the transmission time zone, which is the time zone,
Further comprising
The control unit of the slave station device controls to stop the uplink transmission function in a time zone other than the transmission time zone,
The master station device is
Based on the determination result notified from the slave station apparatus, for each logical link in the slave station apparatus, notification of transmission stop information indicating whether the logical link is stopped or continues to be transmitted is notified. Communication control unit,
Further comprising
The period management unit of the master station device grasps the dormant state of the logical link by holding the notified transmission stop information for each slave station device, and the bandwidth determined for each logical link The individual setting period, which is a request value of the request period, is stored as period information in association with the logical link, and a bandwidth request is received from the slave station apparatus based on the period information and the transmission stop information for each slave station apparatus Determine the bandwidth request period,
The communication control unit allocates a bandwidth for uplink transmission for each logical link to the slave station device for each bandwidth request cycle, and transmits an allocation result to the slave station device for each bandwidth request cycle determined by the cycle management unit. ,
The communication system according to claim 3. The cycle management unit determines the individual setting cycle for each logical link.
The communication system according to claim 4. The slave station device determines an individual setting period for each logical link, and transmits a determination result to the master station device,
The cycle management unit holds the determination result as the cycle information.
The communication system according to claim 4 or 5, wherein The cycle management unit sets a startup request polling cycle, which is a cycle for inquiring transmission of a startup request, for the logical link whose transmission is stopped, as the individual setting cycle corresponding to the logical link,
The communication control unit allocates a bandwidth for transmitting an activation request for each activation request polling period to the logical link that has stopped transmission, and transmits an allocation result for each activation request polling period.
The communication system according to claim 4, 5 or 6. The cycle management unit makes the startup request polling cycle, which is a cycle for inquiring transmission of the startup request, for the logical link whose transmission is stopped, the same as the bandwidth request cycle,
The communication control unit allocates a bandwidth for transmitting an activation request for each activation request polling period to the logical link that has stopped transmission, and transmits an allocation result for each activation request polling period.
The communication system according to claim 4, 5 or 6. The period management unit, for a slave station device that does not have a logical link that is continuing transmission, the maximum value of the individual setting period corresponding to the logical link for which transmission is stopped, as the activation request polling period,
The communication system according to claim 8. The communication control unit allocates a band for uplink transmission to the slave station device so that the transmission time zones of the logical links in one of the slave station devices are mutually continuous time zones,
The communication system according to any one of claims 4 to 9. The communication control unit transmits a transmission time zone for a logical link whose transmission is stopped among the logical links in one slave station device, and a transmission time zone for a logical link that is continuing transmission among the logical links in the slave station device. Assign to the beginning or end of
The communication system according to claim 10. A communication system comprising: a slave station device; and a master station device that allocates a bandwidth for uplink transmission to each of the logical links in the slave station device to the slave station device,
The slave station device is
A bandwidth request for each logical link is transmitted to the master station device, and it is determined for each logical link whether transmission is stopped or transmission is continued, and the determination result is used as transmission stop information. A slave station communication control unit for determining a transmission time zone that is a time zone for performing uplink transmission based on the allocation result received from the station device;
The transmission stop information is held, and a bandwidth request cycle for transmitting a bandwidth allocation request is determined based on an individual setting cycle that is a request value of a bandwidth request cycle determined for each logical link and the transmission stop information. A bandwidth update cycle management unit;
A device control unit that controls to stop the uplink transmission function in a time zone other than the transmission time zone;
With
The slave station communication control unit transmits the bandwidth request for each bandwidth request cycle,
The master station device is
A base station communication control unit for allocating a bandwidth for uplink transmission for each logical link to a slave station device for each predetermined cycle, and transmitting an allocation result for each predetermined cycle;
A communication system comprising: The cycle management unit determines an individual set cycle for each logical link;
The communication system according to claim 12. The master station device determines an individual setting period for each logical link, and transmits a determination result to the slave station device.
The cycle management unit holds the determination result as the cycle information.
The communication system according to claim 12. The master station communication control unit allocates a band for uplink transmission to the slave station device so that the transmission time zones of the logical links in one slave station device are mutually continuous time zones,
The communication system according to any one of claims 12 to 14, wherein The slave station communication control unit transmits transmission stop information to the master station device,
Based on the transmission stop information, the master station communication control unit determines a transmission time zone for a logical link whose transmission is stopped among the logical links in one slave station apparatus, among the logical links in the slave station apparatus. Assign at the beginning or end of the transmission window for the logical link that is continuing transmission,
The communication system according to claim 15. The period management unit determines, as the band request period, a minimum period among individual setting periods corresponding to a logical link that is continuing transmission in one slave station device.
The communication system according to any one of claims 1 to 16. Determining the individual setting period based on service contents for each logical link;
The communication system according to any one of claims 1 to 17. Determining the individual setting period based on the maximum bandwidth set for each logical link;
The communication system according to claim 1, wherein Determining the individual setting period based on a minimum bandwidth set for each logical link;
The communication system according to any one of claims 1 to 19. The master station device is an OLT in the PON system, and the slave station device is an ONU in the PON system.
21. The communication system according to any one of claims 1 to 20, wherein: A master station device that is connected to a plurality of slave station devices via a common communication path and allocates a bandwidth for uplink communication to each slave station device,
When the slave station apparatus suspends some of the plurality of logical links, a period for determining a bandwidth request period in which the slave station apparatus transmits a bandwidth request based on the suspension state of the logical link The management department,
An optical transmitter that transmits an instruction signal instructing a transmission timing of the bandwidth request based on a bandwidth request cycle determined by the cycle management unit;
A master station device comprising: The master station device is a slave station device of a communication system that determines a bandwidth request cycle in which the slave station device transmits a bandwidth request and transmits a transmission timing instruction signal based on the bandwidth request cycle,
A controller that pauses some of the plurality of logical links connected to the master station device;
In response to a transmission timing instruction signal from the master station device, a bandwidth request necessary for data transmission using the logical link and a suspension state of the logical link are transmitted, and the bandwidth request and the suspension state are transmitted to the master station device. A transmitter for determining a bandwidth request period based on;
A receiver for receiving a transmission timing instruction signal transmitted from the master station device;
Based on a transmission timing instruction signal determined based on the dormant state of the logical link, a control unit that controls the start and stop of the transmitter;
A slave station device comprising:

Images