JP2017041700A - Terminal station apparatus and band allocation method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a terminal station apparatus capable of performing delay control according to the priority among terminal units.SOLUTION: A terminal station apparatus 12 receives data from a plurality of terminal units 13 in a manner of time division multiple access. A band allocation section 123 in the terminal station apparatus 12 allocates bandwidth permitting the terminal units 13 transmission for each bandwidth allocation cycle, and decides the timing of transmission start a piece of data of the allocated bandwidth in the order according to the priority among the terminal units 13.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a terminal station apparatus and a bandwidth allocation method.

  Optical access, represented by FTTH (Fiber To The Home), provides economical services by using a passive optical network (PON) in which a terminal equipment and multiple terminal equipment are connected. Realized. In a passive optical communication network, communication between a terminal device and a terminal device is multiplexed by a time division multiplexing method. On the other hand, communication from a terminal device to a terminal device (hereinafter referred to as “uplink communication”) is realized using a control protocol called MPCP (Multi-Point Control Protocol) (for example, see Non-Patent Document 1). ). The transmission amount and transmission start time in uplink communication of each terminal device are centrally controlled in the terminal device, and the control method dynamically changes the transmission amount and static bandwidth allocation that gives the transmission amount fixedly. It can be roughly divided into dynamic bandwidth allocation. As one of dynamic bandwidth allocation, there is one that achieves high bandwidth utilization efficiency by determining a transmission amount using a request amount from each terminal device (see, for example, Patent Document 1).

  Studies are also being made to apply a passive optical communication network to mobile radio communication service networks (hereinafter referred to as “mobile networks”) represented by LTE (Long Term Evolution) and LTE-advanced to make the network more economical. ing. For example, the function of a conventional radio base station is divided into a base station apparatus unit that performs baseband processing and a radio apparatus unit that performs radio processing. Then, the base station apparatus unit is aggregated in the accommodation station and the radio apparatus unit is extended, and a passive optical communication network is applied to a transmission system between the base station apparatus unit and the radio apparatus unit (for example, Patent Documents). 2). In a mobile network, since retransmission control (HARQ: hybrid automatic repeat request) is performed, requirements for delay time between a base station apparatus unit and a radio apparatus unit are severe. Therefore, the uplink communication transmission start time and the transmission permission amount from the terminal device to the terminal device are calculated based on the uplink communication scheduling information notified from the upper device to the user device via the lower device, and notified. (For example, refer to Patent Document 2). As a result, it is possible to transfer an upstream signal from the lower apparatus to the upper apparatus with a low delay.

Japanese Patent No. 3768421 International Publication No. 2014/077168

"IEEE Std. 802.3-2012", IEEE, 2012

  As described above, when a passive optical communication network is used as a transmission system in which both FTTH and a mobile network relay those communications, the same passive optical communication network uses the same FTTH and the mobile network in order to make the best use of the economy. It is assumed that both service network systems will be accommodated. However, the delay characteristics required for these two service network systems are different, and the mobile network is compatible with HARQ. Therefore, a lower delay characteristic stricter than FTTH is required. In addition, it is assumed that the passive optical communication network accommodates various service network systems having different delay characteristics that will be required in the future. When a transmission system accommodates a service network system, a service for relaying data may be different for each terminal device. Therefore, delay control in consideration of the priority of each terminal device has been required.

  In view of the above circumstances, an object of the present invention is to provide a terminal device and a bandwidth allocation method that can perform delay control according to the priority of a terminal device.

  One aspect of the present invention is a terminal device that receives data from a plurality of terminal devices by time division multiple access, and assigns a bandwidth amount that permits transmission to the terminal device for each bandwidth allocation period. A bandwidth allocating unit that determines the timing of starting the transmission of the data so as to be in the order according to the priority of the terminal device.

  One aspect of the present invention is the terminal device described above, wherein the termination device and the plurality of termination devices include a host device connected to the terminal device and a lower device connected to the terminal device. Relaying a plurality of services between the bandwidth allocation unit so that the transmission start timing of the bandwidth amount data is in an order according to the priority of the services relayed by the termination device decide.

  Another aspect of the present invention is the above-described terminal device that receives scheduling information indicating a service communication schedule and determines the priority of the terminal device that relays communication data indicated by the scheduling information. And a priority determination unit.

  One embodiment of the present invention is the terminal device described above, wherein the plurality of services include at least a radio service.

  One aspect of the present invention is the terminal device described above, wherein the bandwidth allocation unit divides the bandwidth amount allocated to the termination device, and starts transmission of data for each of the divided bandwidth amounts. The timing is determined according to the priority of the termination device.

  Another aspect of the present invention is a bandwidth allocation method executed by a terminal device that receives data from a plurality of termination devices by time division multiple access, and permits transmission to the termination device for each bandwidth allocation period. A bandwidth allocation step of allocating a bandwidth amount and determining a transmission start timing of the bandwidth amount data in an order according to a priority of the termination device.

  According to the present invention, it is possible to perform delay control in accordance with the priority of the terminal device.

1 is a configuration diagram of a communication system according to a first embodiment. It is a functional block diagram which shows the structure of the terminal station apparatus by the embodiment. It is a figure which shows the operation | movement flow of the band allocation process which the band allocation part of the terminal station apparatus by the same embodiment performs. It is a figure which shows the example of the determination method of the transmission start time by the embodiment. It is a figure which shows the example of the determination method of the transmission start time by the embodiment. It is a block diagram of the communication system by 2nd Embodiment. It is a functional block diagram which shows the structure of the terminal station apparatus by the embodiment. It is a figure which shows the operation | movement flow of the information extraction process which the information extraction part of the terminal device by the same embodiment performs. It is a figure which shows the operation | movement flow of the request amount calculation process which the request amount calculation part of the terminal station apparatus by the same embodiment performs. It is a figure which shows the operation | movement flow of the priority information preservation | save process which the priority information preservation | save part of the terminal device by the same embodiment performs. It is a figure which shows the operation | movement flow of the band allocation process which the band allocation part of the terminal station apparatus by the same embodiment performs. It is a figure which shows the example of the determination method of the transmission start time by the embodiment. It is a figure which shows the example of the determination method of the transmission start time by the embodiment. It is a figure which shows the example of the determination method of the transmission start time by the embodiment.

  Embodiments of the present invention will be described in detail with reference to the drawings. In addition, in this specification and drawing, the component with the same code | symbol shall show the mutually same thing.

[First embodiment]
FIG. 1 is a configuration diagram of a communication system 10 according to the present embodiment. As shown in the figure, the communication system 10 includes a terminal device 12 and K terminal devices (K is an integer equal to or greater than 1). In the figure, K terminal devices 13 are described as terminal devices 13-1 to 13-K, respectively.

  The terminal station device 12 and the terminal device 13 constitute a passive optical network (PON). For example, the terminal station device 12 is an OLT (Optical Line Terminal: optical subscriber line termination device), and the termination device 13 is an ONU (Optical Network Unit: optical subscriber line network device). The terminal device 12 and the terminal device 13 are one-to-many and are connected by a relay network using the optical fiber 6 and the optical splitter 7. That is, the terminal station device 12 and the terminal device 13 are connected by distributing a communication signal transmitted through one optical fiber 6 into a plurality of signals by the optical splitter 7. The terminal station device 12 multiplexes and transmits signals (downlink signals) to be transmitted to the terminal devices 13-1 to 13-K by the TDM method. The optical splitter 7 transfers the multiplexed downstream signal as it is to the terminators 13-1 to 13-K. Further, signals (uplink signals) transmitted from the terminal devices 13-1 to 13 -K to the terminal device 12 are multiplexed by the optical splitter 7 in a time division multiple access (TDMA) system and transmitted to the terminal device 12. The

  FIG. 2 is a functional block diagram showing a configuration of the terminal station device 12 in the present embodiment, and only functional blocks related to the present embodiment are extracted and shown. The terminal device 12 includes a lower-level transmission / reception unit 121, a priority information storage unit 122, and a bandwidth allocation unit 123.

  The lower transmission / reception unit 121 is an interface responsible for data transmission / reception with the terminal device 13. The priority information storage unit 122 stores priority information. The priority information indicates the priority of each terminal device 13. The bandwidth allocating unit 123 determines a bandwidth amount (transmission permitted amount) that permits transmission of uplink communication to each terminal device 13 and a transmission start timing of uplink communication data for each bandwidth allocation period. The amount of bandwidth is indicated by the data length, for example. The band allocating unit 123 determines the transmission start timing of each terminal device 13 so that the higher the priority of the terminal device 13 is, the earlier the timing becomes. The transmission start timing and the bandwidth amount calculated by the bandwidth allocating unit 123 are notified to the terminating device 13 via the lower-level transmission / reception unit 121.

FIG. 3 is a diagram showing an operation flow of a bandwidth allocation process executed by the bandwidth allocation unit 123 of the terminal station device 12. The bandwidth allocation unit 123 executes a bandwidth allocation process at intervals of the bandwidth allocation period.
In the bandwidth allocation process, first, the bandwidth allocation unit 123 initializes the remaining bandwidth C with an allocatable amount in the bandwidth allocation cycle (step S101).

  The bandwidth allocation unit 123 determines the transmission permission amount of each terminal device 13 (step S102). Specifically, the band allocating unit 123 selects the terminal devices 13 in an arbitrary order or a predetermined order, and executes the processes of steps S103 to S104 below for each of the selected terminal devices 13.

  The bandwidth allocation unit 123 determines a distribution amount for the selected termination device 13 in the remaining bandwidth C (step S103). The amount of distribution can be determined by any method. For example, the band allocation unit 123 may distribute the same band to all the terminal devices 13 or may distribute a fixed band. The bandwidth allocating unit 123 may determine the distribution amount based on the uplink communication data amount notified from the termination device 13 or the uplink communication data amount obtained from the uplink communication schedule of the termination device 13. . Alternatively, the bandwidth allocation unit 123 may monitor the upstream traffic from the termination device 13 and determine the distribution amount based on the bandwidth request amount predicted from the past traffic volume of the termination device 13. The bandwidth allocating unit 123 allocates the determined distribution amount as a transmission permission amount to the selected termination device 13 (step S104).

  If the bandwidth allocation unit 123 determines that the processing of steps S103 to S104 has been executed for all the terminal devices 13, the bandwidth allocation unit 123 performs the processing of step S105. That is, the bandwidth allocating unit 123 determines a time length for permitting transmission to each terminal device 13 based on the transmission permission amount allocated to each terminal device 13. Further, the bandwidth allocating unit 123 assigns the transmission start time to each terminal device 13 based on the length of time during which transmission is permitted to each terminal device 13 and the priority of each terminal device 13 acquired from the priority information storage unit 122. Is determined (step S105). The lower transmission / reception unit 121 notifies the transmission permission indicating the transmission start time and the transmission permission amount determined by the band allocating unit 123 to each termination device 13 using a control signal. Note that the band allocating unit 123 may notify each terminal device 13 of the transmission permission for the relay network through a line different from the optical fiber 6.

  FIG. 4 is a diagram illustrating an example of a transmission start time determination method. Here, it is assumed that the five termination devices 13 are termination devices # 1 to # 5. The priority is higher in the order of the terminal device # 1, the terminal device # 2, the terminal device # 3, the terminal device # 4, and the terminal device # 5. The bandwidth allocating unit 123 starts from the head of the bandwidth allocation cycle in the order of the terminal devices # 1, # 2, # 3, # 4, and # 5 so that the transmission start time is earlier in the order of higher priority within the bandwidth allocation cycle. Allocate a transmission start time.

  FIG. 5 is a diagram illustrating another example of a transmission start time determination method. In the figure, the bandwidth allocation unit 123 divides the transmission permission amount of each of the terminal devices # 1 to # 5 into N (N is an integer of 2 or more). In the figure, the case of N = 2 is shown. The bandwidth allocation unit 123 divides the bandwidth allocation cycle into a plurality of times (N times). The bandwidth allocating unit 123, in each of the N-divided bandwidth allocation periods, in order of the terminal devices # 1, # 2, # 3, # 4, and # 5 so that the transmission start time becomes earlier in the order of higher priority. Allocate a transmission start time.

  If the transmission interval of one terminal device 13 is large, the time until another terminal device 13 waits for the next transmission timing is extended, and the delay increases. Therefore, by dividing the transmission opportunity of one terminal device 13 a plurality of times, the transmission interval of the entire terminal device 13 can be narrowed, and the delay can be reduced. Therefore, it is possible to assign a high frequency band to the entire termination device 13.

  As described above, a terminal device connected to a plurality of terminal devices allocates a bandwidth amount that is permitted to be transmitted to the terminal device for each bandwidth allocation period, and determines the transmission start timing of data of the allocated bandwidth amount. The order is determined according to the priority of the device. Thus, since data transmission is permitted in the order corresponding to the priority of each terminal device for each band allocation cycle, the terminal device with higher priority can transmit uplink data with a shorter delay.

[Second Embodiment]
In the embodiment of the present invention, a plurality of services are accommodated simultaneously in the transmission system. Hereinafter, a case where a passive optical communication network system is used as a transmission system will be described as an example. When a transmission system or a device constituting the transmission system accommodates a service indicates that the communication of the service is relayed.

FIG. 6 is a configuration diagram of the communication system 20 according to the present embodiment. As shown in the figure, the communication system 20 includes a host device 21a and 21b, a terminal device 22, a terminal device 23a of P units (P is an integer of 1 or more), and Q units (Q is an integer of 1 or more). ) Terminal device 23b, P subordinate devices 24a, and Q subordinate devices 24b.
In the figure, P terminal devices 23a are described as terminal devices 23a-1 to 23a-P, respectively, and Q terminal devices 23b are described as terminal devices 23b-1 to 23b-Q, respectively. In the figure, P subordinate devices 24a are described as subordinate devices 24a-1 to 24a-P, respectively, and Q subordinate devices 24b are described as subordinate devices 24b-1 to 24b-Q, respectively. Terminating devices 23a-p (p is an integer from 1 to P) are connected to lower devices 24a-p, and terminating devices 23b-q (q is an integer from 1 to Q) are connected to lower devices 24b-q. .
Hereinafter, the upper devices 21a and 21b are collectively referred to as the upper device 21, the termination device 23a and the termination device 23b are collectively referred to as the termination device 23, and the lower device 24a and the lower device 24b are collectively referred to as the lower device. 24.

  The upper device 21 and the lower device 24 are different for each service to be accommodated. Here, the upper apparatus 21a and the lower apparatus 24a accommodate the A system, and the upper apparatus 21b and the lower apparatus 24b accommodate the B system. The A system is a mobile network that accommodates mobile radio communication services, for example. In the A system, the upper apparatus 21a is a base station apparatus section, and the lower apparatus 24a is a radio apparatus section. The B system is, for example, an FTTH that accommodates a data communication service. In the B system, the upper device 21b is a line collecting switch, and the lower device 24b is a home gateway. The host device 21a and the host device 21b are each connected to a host network. In the case of a mobile network, one or more user devices are further connected to the lower device 24.

  The terminal station device 22 and the terminal device 23 constitute a passive optical communication network. For example, the terminal device 22 is an OLT, and the terminal device 23 is an ONU. The terminal device 22 and the terminal device 23 are one-to-many and are connected by a relay network using the optical fiber 6 and the optical splitter 7. That is, the terminal station device 22, the terminal devices 23 a-1 to 23 a -P, and the terminal devices 23 b-1 to 23 b -Q distribute the communication signal transmitted through one optical fiber 6 to a plurality of signals by the optical splitter 7. Connected. The terminal station device 22 multiplexes and transmits signals (downlink signals) to be transmitted to the terminal devices 23a-1 to 23a-P and the terminal devices 23b-1 to 23b-Q using the TDM method. The optical splitter 7 transfers the multiplexed downstream signal as it is to the terminal devices 23a-1 to 23a-P and the terminal devices 23b-1 to 23b-Q. Further, signals (uplink signals) transmitted from the terminal devices 23a-1 to 23a-P and the terminal devices 23b-1 to 23b-Q to the terminal device 22 are multiplexed by the optical splitter 7 by the TDMA method, and the terminal devices 22 is transmitted.

  FIG. 7 is a functional block diagram showing the configuration of the terminal device 22 in the present embodiment, and only functional blocks related to the present embodiment are extracted and shown. The terminal device 22 includes a higher-level transmission / reception unit 221, a lower-level transmission / reception unit 222, an information extraction unit 223, a request amount calculation unit 224, a priority information storage unit 225, a priority determination unit 226, and a bandwidth allocation unit 227.

  The upper transmission / reception unit 221 is an interface responsible for data transmission / reception with the upper apparatus 21. The lower transmission / reception unit 222 is an interface responsible for data transmission / reception with the terminal device 23. The information extraction unit 223 receives scheduling information indicating a communication schedule of the system A from the upper apparatus 21a and extracts necessary information. Based on the information extracted by the information extraction unit 223, the request amount calculation unit 224 calculates a relay network request amount which is a bandwidth amount necessary for uplink communication by the terminating device 23a belonging to the A system. The priority information storage unit 225 stores priority information. The priority determination unit 226 determines the priority of the termination device 23 based on the scheduling information. The bandwidth allocating unit 227 calculates the uplink transmission relay transmission permission for each terminal device 23. The relay network transmission permission includes a transmission start time and a transmission permission amount. The band allocating unit 227 determines the transmission start time of each terminal device 23 so that the higher the priority of the terminal device 23 is, the earlier the transmission start time is. Information indicating the transmission permission for the relay network calculated by the band allocating unit 227 is notified to the terminating device 23 via the lower-level transmission / reception unit 222.

  In the present embodiment, the scheduling information is reported from the host device 21a through an interface different from the main signal (the signal from the host device 21a to the user device or the lower device 24a). However, the scheduling information is the main signal. May be included. In this case, the terminal station device 22 does not provide an interface for receiving scheduling information, and the higher-level transmission / reception unit 221 snoops scheduling information from the main signal received from the higher-level device 21a and transfers the scheduling information to the information extraction unit 223.

  FIG. 8 is a diagram showing an operation flow of the information extraction process executed by the information extraction unit 223 of the terminal device 22. The information extraction unit 223 executes an information extraction process every time scheduling information is received from the host device 21a. Note that the information extraction unit 223 may execute the information extraction process at a certain periodic interval by collecting the received scheduling information.

  In the information extraction step, the information extraction unit 223 extracts destination information indicating the destination user apparatus and allocation information related to transmission of the uplink signal of the user apparatus from the received scheduling information (step S301). The allocation information is information that can acquire the transmission timing and transmission amount of uplink communication allocated to the user apparatus. The information extraction unit 223 uses the time when the scheduling information is received to estimate the time when the uplink communication data (uplink signal) from the user apparatus arrives at the termination device 23a (step S302). Let the estimated time be the estimated arrival time. The information extraction unit 223 transfers the destination information, the allocation information, and the estimated arrival time to the request amount calculation unit 224 (Step S303).

FIG. 9 is a diagram illustrating an operation flow of a request amount calculation process executed by the request amount calculation unit 224 of the terminal station device 22. The request amount calculation unit 224 executes the request amount calculation step at intervals of the bandwidth allocation period.
In the request amount calculation step, the request amount calculation unit 224 uses the destination information, the allocation information, and the estimated arrival time received from the information extraction unit 223 to calculate the amount of data that arrives at each terminal device 23a for each bandwidth allocation period. (Step S401). The request amount calculation unit 224 transfers the arrival data amount for each termination device 23a in the next bandwidth allocation cycle to the bandwidth allocation unit 227 as the transmission request amount of the termination device 23a, that is, the relay network request amount (step S402). .

  FIG. 10 is a diagram illustrating an operation flow of the priority information storage process executed by the priority information storage unit 225 of the terminal station device 22. The priority information storage unit 225 executes a priority information storage process every time the priority information of any terminal device 23 is changed. In the priority information storage step, the priority information storage unit 225 stores the priority information after the change of the terminal device 23 when the priority information of the arbitrary terminal device 23 is changed, and the bandwidth allocation unit. (Step S501).

  The priority information stored in the priority information storage unit 225 is, for example, information in which information for specifying the terminal device 23 is associated with information indicating the priority. The information indicating the priority may be information indicating the service accommodated by the terminal device 23. The priority of the service accommodated by the terminal device 23 becomes the priority of the terminal device 23. In this case, priority information for each service is stored in the priority information storage unit 225.

  The priority information may be manually input for registration or change, and may be determined and set by the priority determination unit 226 based on the scheduling information. When registration or change is performed only manually, the terminal device 22 may not include the priority determination unit 226. When the priority information is set based on the scheduling information, the priority determination unit 226 determines the priority of the terminal device 23 based on the scheduling information received from the host device 21a, and further, the priority information storage unit 225. Is compared with the stored priority information to determine whether the priority has been changed. If the priority determination unit 226 determines that the priority has been changed, the priority determination unit 226 outputs the changed priority of the terminal device 23 to the priority information storage unit 225.

  In the scheduling information received from the host device A, information that can identify the termination device 23 belonging to the A system is set. For example, it is assumed that the scheduling information received from the upper device 21a of the A system includes information for specifying the lower device 24 or the user device. The priority determination unit 226 corresponds to the service accommodated by the system A with the priority of the terminal device 24 connected to the lower device 24 indicated by the scheduling information or the lower device 24 accommodating the user device indicated by the scheduling information. Judge as priority. In addition, information for specifying a service or priority itself may be set in the scheduling information. Services that use scheduling information include at least wireless services (including services provided by mobile networks).

FIG. 11 is a diagram showing an operation flow of a bandwidth allocation process executed by the bandwidth allocation unit 227 of the terminal station device 22. The band allocation unit 227 executes the band allocation process at intervals of the band allocation period.
In the bandwidth allocation step, first, the bandwidth allocation unit 227 initializes the remaining bandwidth C with an allocatable amount in the bandwidth allocation cycle (step S601).

  The bandwidth allocation unit 227 first determines the transmission permission amount of each terminal device 23a belonging to the A system (step S602). Specifically, the bandwidth allocating unit 227 selects the terminal devices 23a belonging to the A system in an arbitrary order or a predetermined order, and performs the processes of steps S603 to S604 below for each of the selected terminal devices 23a. Run.

  The bandwidth allocation unit 227 determines the transmission permission amount based on the requested amount of the selected termination device 23a and the current remaining bandwidth C (step S603). In other words, the bandwidth allocation unit 227 sets the transmission permission amount of the selected termination device 23a as the smaller one of the relay network request amount (transmission request amount) of the termination device 23a and the remaining bandwidth C. The bandwidth allocation unit 227 updates the remaining bandwidth C to a value obtained by subtracting the transmission permission amount of the selected termination device 23a from the current value (step S604). If the bandwidth allocation unit 227 determines that the processing in steps S603 to S604 has been executed for all the terminal devices 23a belonging to the A system, the bandwidth allocation unit 227 performs the processing in step S605.

  The bandwidth allocation unit 227 determines the transmission permission amount of each terminal device 23b belonging to the B system (step S605). Specifically, the bandwidth allocation unit 227 selects the termination device 23b belonging to the B system in an arbitrary order or in an order determined in advance, and performs the processes in steps S606 to S607 below for each of the selected termination devices 23b. Execute. That is, the bandwidth allocation unit 227 determines a distribution amount for the selected termination device 23b in the remaining bandwidth C (step S606). The amount of distribution can be determined by any method. For example, the band allocation unit 227 may distribute the same band to all the terminal devices 23b or may distribute a fixed band. The bandwidth allocating unit 227 may determine the distribution amount based on the uplink communication data amount notified from the termination device 23b or the uplink communication data amount obtained from the uplink communication schedule of the termination device 23b. . Alternatively, the bandwidth allocation unit 227 may monitor the upstream traffic from the terminal device 23b and determine the distribution amount based on the bandwidth request amount predicted from the traffic amount of the past terminal device 23b. The band allocating unit 227 allocates the determined distribution amount as a transmission permission amount to the selected termination device 23b (step S607).

  If the bandwidth allocation unit 227 determines that the processing in steps S606 to S607 has been executed for all the terminal devices 23b belonging to the B system, the bandwidth allocation unit 227 performs the processing in step S608. That is, the bandwidth allocation unit 227 determines a time length for permitting transmission to each terminal device 23 based on the distribution amount allocated to each terminal device 23. Further, the bandwidth allocating unit 227 assigns the transmission start time to each terminal device 23 based on the time length permitted to transmit to each terminal device 23 and the priority of each terminal device 23 acquired from the priority information storage unit 225. Is determined (step S608). The lower transmission / reception unit 222 notifies each termination device 23 of the transmission permission for the relay network indicating the transmission start time and the transmission permission amount determined by the bandwidth allocation unit 227 by a control signal. The band allocating unit 227 may notify each terminal device 23 of the transmission permission for the relay network through a line different from the optical fiber 6.

  FIG. 12 is a diagram illustrating an example of a transmission start time determination method. In the figure, termination devices # 1 and # 2 are termination devices 23a belonging to the A system, and termination devices # 3 to # 5 are termination devices 23b belonging to the B system. The terminating device 23a that accommodates the A system has a higher priority than the terminating device 23b that accommodates the B system. Alternatively, the service provided by the A system has a higher priority than the service provided by the B system. The bandwidth allocation unit 227 preferentially allocates the transmission start time at the head of the bandwidth allocation cycle to the termination device 23a (termination devices # 1, # 2) of the A system within the bandwidth allocation cycle, and terminates the termination system of the B system. 23b (termination devices # 3 to # 5) is assigned a transmission start time later than the transmission start time assigned to the termination device 23a of the A system.

The method for determining the transmission start time is not limited to this, and may be determined as shown in FIG. 13 or FIG.
FIG. 13 is a diagram illustrating another example of a method for determining a transmission start time. The bandwidth allocation unit 227 divides the transmission permission amount of each of the terminal devices 23a of the A system into N, and sets the divided transmission permission amounts Da (1) to Da (N). The bandwidth allocation unit 227 divides the bandwidth allocation cycle into N and sets the bandwidth allocation cycles as C (1) to C (N). N is an integer equal to or greater than 2, but the figure shows a case where N = 2. The band allocating unit 227 collects the head of the divided band allocation period C (i) (i is an integer not less than 1 and not more than N) and grants the divided transmission permission to the terminal device 23a (terminal devices # 1, # 2) of the A system. The transmission start time of the quantity Da (i) is assigned. The bandwidth allocation unit 227 allocates the transmission start time to the terminal device 23a (terminal devices # 3 to # 5) of the B system after allocating the transmission start time to the terminal device 23a of the A system.

In this way, when the transmission permission amount of the A system is divided into N and the transmission start time is determined in a plurality of times, the transmission start time is assigned to the remaining time zone for the terminating device 23b of the B system. Therefore, the transmission start time may be determined in several times by dividing the transmission permission amount of a part of the terminal devices 23b of the B system so as not to overlap with the transmission time of the A system. In the figure, the transmission permission amount of the terminal device # 4 is divided.
Thereby, for example, it is possible to divide the allocation amount to the terminal device 23 that uses at least the wireless service into N, and to permit data transmission by increasing the transmission frequency by N times.

  FIG. 14 is a diagram illustrating still another example of the method for determining the transmission start time. The bandwidth allocation unit 227 divides the transmission permission amount of each of the terminal devices 23a of the A system into N, and sets the divided transmission permission amounts Da (1) to Da (N). Furthermore, the bandwidth allocation unit 227 also divides the transmission permission amount of each of the terminal devices 23b of the B system into N, and sets the divided transmission permission amounts Db (1) to Db (N). N is an integer equal to or greater than 2, but the figure shows a case where N = 2. The bandwidth allocation unit 227 divides the bandwidth allocation cycle into N and sets the bandwidth allocation cycles as C (1) to C (N). The bandwidth allocation unit 227 determines that the transmission start time of the A system termination device 23a is greater than the transmission start time of the B system termination device 23b in each of the divided bandwidth allocation cycles C (i) (i is an integer not less than 1 and not greater than N). So that the transmission start times of the divisional transmission permission amounts Da (i) of the terminal device 23a (terminal devices # 1 and # 2) are allotted to the head so that the terminal device 23b (terminal device ##) 3 to # 5) are assigned transmission start times of the divided transmission permission amounts Db (i). In this way, both systems divide the bandwidth into N and allocate a small bandwidth with high frequency.

According to the present embodiment, the terminal station device 22 and the plurality of termination devices 23 are configured to communicate a plurality of services between the upper device 21 connected to the terminal device 22 and the lower device 24 connected to the termination device 23. Relay. The bandwidth allocation unit 227 of the terminal station device 22 determines the transmission start timing of each termination device 23 within the bandwidth allocation period according to the priority of the service with which the termination device 23 relays communication.
By assigning the transmission start timing in accordance with the priority, particularly when a wireless system is connected, there is an effect of reducing the delay.

The predetermined priority corresponding to the service can be set based on scheduling information from the higher-level device.
In addition, the terminal station device 22 can determine the amount of uplink data before uplink data arrives and perform bandwidth allocation by using scheduling information for uplink transmission from each terminal device 23a of the A system. . Therefore, it is possible to reduce the delay of uplink transmission of the A system.

  In the present embodiment, a DBA (Dynamic Bandwidth Allocation) is arranged according to the priority according to the service in a configuration including a host device and a lower device. According to the present embodiment, even if a buffer or the like is taken into account, for example, bandwidth allocation can be performed with priority over a wireless service.

  According to the embodiment described above, the terminal station device can arrange the band allocated to the terminal device according to the priority of the terminal device. Therefore, it is possible to provide a terminal device that constitutes a passive optical communication network that accommodates a plurality of services including services with severe delay restrictions such as wireless services.

  You may make it implement | achieve the function of the terminal station apparatus 12 in the embodiment mentioned above, and the terminal station apparatus 22 with a computer. In that case, a program for realizing the functions of the terminal device 12 and the terminal device 22 is recorded on a computer-readable recording medium, and the program recorded on the recording medium is read by a computer system. It may be realized by executing. Here, the “computer system” includes an OS and hardware such as peripheral devices. The “computer-readable recording medium” refers to a storage device such as a flexible medium, a magneto-optical disk, a portable medium such as a ROM and a CD-ROM, and a hard disk incorporated in a computer system. Furthermore, the “computer-readable recording medium” dynamically holds a program for a short time like a communication line when transmitting a program via a network such as the Internet or a communication line such as a telephone line. In this case, a volatile memory inside a computer system serving as a server or a client in that case may be included and a program held for a certain period of time. The program may be a program for realizing a part of the functions described above, and may be a program capable of realizing the functions described above in combination with a program already recorded in a computer system.

  The embodiment of the present invention has been described in detail with reference to the drawings. However, the specific configuration is not limited to this embodiment, and includes designs and the like that do not depart from the gist of the present invention.

  It can be used for a system that performs communication by time division multiple access.

6 Optical fiber 7 Optical splitter 10 Communication system 12 Terminal station devices 13, 13-1 to 13-K Termination device 20 Communication system 21a Host device 21b Host device 22 Terminal station devices 23, 23a-1 to 23a-P, 23b-1 23b-Q Terminating devices 24a-1 to 24a-P, 24b-1 to 24b-Q Subordinate device 121 Lower transmission / reception unit 122 Priority information storage unit 123 Band allocation unit 221 Upper transmission / reception unit 222 Lower transmission / reception unit 223 Information extraction unit 224 Request amount calculation unit 225 Priority information storage unit 226 Priority determination unit 227 Bandwidth allocation unit

Claims (6)

A terminal device that receives data from a plurality of terminal devices by time division multiple access,
A bandwidth allocation unit that allocates a bandwidth amount that is permitted to be transmitted to the termination device for each bandwidth allocation period, and determines the transmission start timing of the bandwidth amount data in an order according to the priority of the termination device ,
A terminal device comprising: The termination device and the plurality of termination devices relay communication of a plurality of services between an upper device connected to the terminal device and a lower device connected to the termination device,
The bandwidth allocating unit determines the transmission start timing of the bandwidth amount data so that the termination device is in an order according to the priority of the service relaying communication.
The terminal device according to claim 1. Further comprising a priority determination unit that receives scheduling information indicating a communication schedule of a service and determines a priority of the terminal device that relays communication data indicated by the scheduling information;
The terminal device according to claim 2. The plurality of services include at least wireless services.
The terminal device according to claim 2 or claim 3, wherein The bandwidth allocating unit divides the bandwidth amount allocated to the termination device, and determines a data transmission start timing for each of the divided bandwidth amounts according to the priority of the termination device;
The terminal device according to any one of claims 1 to 4, characterized in that: A bandwidth allocation method executed by a terminal device that receives data from a plurality of terminal devices by time division multiple access,
A bandwidth allocation step of allocating a bandwidth amount that is permitted to be transmitted to the termination device for each bandwidth allocation period, and determining a transmission start timing of the bandwidth amount data in an order according to the priority of the termination device ,
A bandwidth allocation method characterized by comprising:

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