CONTROL SYSTEM, CONTROL METHOD, CONTROLLER, AND PROGRAM

Abstract

The purpose of this disclosure is to provide a packet transmission control system, a control method, a controller, and a program that enable scheduling even with time synchronization with degraded accuracy.　This disclosure is a control system that controls wireless network traffic, the control system being characterized by comprising a terminal and an access point that transmit packets to each other through the wireless network, and a controller that performs transmission control with respect to the terminal and the access point, and characterized in that the controller: acquires a time synchronization deviation between the terminal and the access point; determines, on the basis of the required band of at least each of traffic flows communicated from the terminal, a band control value for each of the traffic flows; and notifies the terminal and the access point of a transmission time corresponding to the band control value and the time synchronization deviation, and a transmission volume corresponding to the band control value.

Description

[Technical field]

[0001] The present disclosure relates to a control system, a control method, a controller, and a program for allocating a communication band within an access network. [Background technology]

[0002] In recent years, studies have been conducted on accommodating multiple services and applications with various network requirements on the same network infrastructure. To achieve this, it is necessary to guarantee the quality required by each service or application accommodated on the same network in the end-to-end sections from "terminal to terminal" or "terminal to application server."

[0003] The end-to-end of a network can be divided into wireless and wired sections. Among them, in the wireless section, there is a priority control function called Enhanced Distributed Channel Access (EDCA) of IEEE802.11 as an existing technology (Non-Patent Documents 1 and 2).

[0004] However, EDCA is a control system that operates on a terminal (destination) basis, and it is difficult to control on a traffic flow basis, which would enable quality control on a service and application basis. However, by applying the technology described in Non-Patent Document 3, it is possible to realize quality control on a service and application basis.

[0005] The technology in Non-Patent Document 3 is based on the premise that time synchronization is operating ideally, but for example, time synchronization usually generates errors. Furthermore, while the technology in Non-Patent Document 3 can be applied regardless of the type of network, on the other hand, the accuracy may be degraded by performing time synchronization communication on a network with large jitter, such as wireless LAN. As a result, each terminal and access point may transmit packets at a time that deviates from the time assumed by the controller, which may cause the scheduler to not follow the schedule. [Prior art documents] [Non-patent literature]

[0006] [Non-Patent Document 1] IEEE 802.11e-2005 - IEEE Standard for Information technology--Local and metropolitan area networks--Specific requirements--Part 11: Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) Specifications - Amendment 8: Medium Access Control (MAC) Quality of Service Enhancements [Non-Patent Document 2] Masahiro Otani, Naoki Urano, Toru Ueda: IEEE802.11e: Wireless LAN standard for achieving QoS,” Journal of the Institute of Image Information and Television Engineers, Vol. 57, No. 11, pp. 1459-1465 (2003) [Non-Patent Document 3] Yuki Sakagami, Kazuki Aiura, Tatsuya Fukui, Ryohei Tsugami, Tomohiro Taniguchi, Katsuya Minami: Proposal of quality control technology by centralized control independent of wireless network, IEICE General Conference, March 9, 2021, B-6-5 Summary of the Invention [Problem to be solved by the invention]

[0007] An object of the present invention is to provide a packet transmission control system, a control method, a controller, and a program that are capable of scheduling even with time synchronization with degraded accuracy. [Means for solving the problem]

[0008] In the present disclosure, the controller records the time synchronization deviation of each terminal and access point in advance in a database unit. Each terminal and access point notifies the controller of the amount of accumulated packets, and the controller records the amount of accumulated packets in the database unit. The controller determines the packet transmission time based on the time synchronization deviation and the amount of accumulated packets recorded in the database unit, and notifies each terminal and access point of the determined information as a scheduler. The terminal and access point transmit packets at the packet transmission time set by the scheduler. This makes it possible to transmit packets according to the scheduler even with time synchronization with degraded accuracy, and makes it possible to avoid packet transmission failures due to overlapping transmission timing.

[0009] Specifically, the control system of the present disclosure comprises: A control system for controlling traffic in a wireless network, comprising: a terminal and an access point for transmitting packets to each other via the wireless network; A controller that performs transmission control on the terminal and the access point; It is equipped with The controller: Obtaining a time synchronization deviation between the terminal and the access point; determining a bandwidth control value for each traffic flow based on at least a required bandwidth for each traffic flow notified from the terminal; notifying the terminal and the access point of a transmission time corresponding to the bandwidth control value and the deviation of the time synchronization, and a transmission amount corresponding to the bandwidth control value; It is characterized by:

[0010] Specifically, the control method of the present disclosure includes: A method for controlling traffic in a wireless network, comprising: The control method includes a transmission control performed by a controller on a terminal and an access point that transmit packets to each other via the wireless network, Obtaining a time synchronization deviation between the terminal and the access point; The present invention is characterized in that a bandwidth control value for each traffic flow is determined based on the required bandwidth for each traffic flow notified at least from the terminal, and the terminal and the access point are notified of the bandwidth control value, a transmission time corresponding to the time synchronization deviation, and a transmission amount corresponding to the bandwidth control value.

[0011] Specifically, the controller of the present disclosure includes: A controller for controlling traffic in a wireless network, comprising: The controller is a device that performs transmission control on terminals and access points that transmit packets to each other via the wireless network, Obtaining a time synchronization deviation between the terminal and the access point; The present invention is characterized in that it has a function of determining a bandwidth control value for each traffic flow based on the required bandwidth for each traffic flow notified at least from the terminal, and notifying the terminal and the access point of the bandwidth control value.

[0012] The controller of the present disclosure can be realized by a computer and a program, and the program can be recorded on a recording medium or provided via a network. The program of the present disclosure is a program for realizing a computer as each functional unit of the controller according to the present disclosure, and is a program for causing a computer to execute each step of the method executed by the controller according to the present disclosure. Effect of the Invention

[0013] According to the present invention, it is possible to provide a packet transmission control system, a control method, a controller, and a program that are capable of scheduling even with time synchronization with degraded accuracy. [Brief description of the drawings]

[0014] [Figure 1] 1 illustrates an example system configuration of the present disclosure. [Diagram 2] 1 shows an example of a sequence executed by the system of the present disclosure. [Diagram 3] 4 shows an example of a bandwidth control value determined by a controller. [Figure 4] FIG. 1 is an explanatory diagram of a problem to be solved by the present disclosure. [Diagram 5] 13 shows an example of a guard time set in the present disclosure. [Figure 6] 1 illustrates an example of a system configuration according to a first embodiment. [Figure 7] FIG. 2 is a diagram illustrating an example of information organized in a database DB. [Figure 8] FIG. 2 is a flowchart illustrating the operation executed by the system of the first embodiment. [Figure 9] FIG. 11 is a diagram for explaining an example of information organized in a database DB in the second embodiment. [Figure 10] FIG. 11 is a flowchart illustrating the operation executed by the system of the second embodiment. [Figure 11] FIG. 13 is a diagram for explaining an example of information organized in a database DB in the third embodiment. [Figure 12] FIG. 11 is a flowchart illustrating the operation executed by the system of the third embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] Hereinafter, the embodiments of the present disclosure will be described in detail with reference to the drawings. Note that the present disclosure is not limited to the embodiments shown below. These implementation examples are merely illustrative, and the present disclosure can be implemented in various forms with various modifications and improvements based on the knowledge of those skilled in the art. Note that components with the same reference numerals in this specification and drawings are assumed to indicate the same components.

[0016] (Summary of the Disclosure) An example of a system configuration of the present disclosure is shown in Fig. 1. The system of the present disclosure is a control system that controls traffic of a main signal network 15, which is a wireless network, and includes a terminal 11 and an access point 12 that transmit packets to each other via the main signal network 15, and a controller 13 that performs transmission control for the terminal 11 and the access point 12. The controller 13 may be realized by a computer and a program.

[0017] 2 shows an example of a sequence executed by the system of the present disclosure. The controller 13 determines a bandwidth control value for each traffic flow based on the required bandwidth for each traffic flow notified at least from the terminal 11, and notifies the determined bandwidth control value to the terminal 11 and the access point 12 as a scheduler. The controller 13 calculates a bandwidth control value for each traffic flow using the required bandwidth for each traffic flow notified from the terminal 11. Therefore, the system of the present disclosure can guarantee the bandwidth for each traffic flow.

[0018] 3 shows an example of the bandwidth control values ​​determined by the controller 13. The bandwidth control values ​​include transmission times t1 to t8 and transmission durations T1 to T8.

[0019] The system of the present disclosure performs time synchronization by connecting the terminal 11 and the access point 12 to a time synchronization network 16. Any time synchronization method can be used in the time synchronization network 16, and for example, NTP (Network Time Protocol) or PTP (Precision Time Protocol) can be used.

[0020] If the time synchronization network 16 is normal and the time T N and time T of access point 12 A If these are equal, the time t2 at which the access point 12 transmits the packet is sufficiently late compared to the time t1 at which the terminal 11#N transmits the packet, so that the transmission timings do not collide. However, if the time synchronization network 16 deteriorates and the time TN and time T of access point 12 A If they are not equal, as shown in FIG. 4, time t1 at which terminal 11#N transmits a packet is close to time t2 at which access point 12 transmits, so that the packet transmission timings overlap and transmission fails.

[0021] Therefore, in the present disclosure, as shown in FIG. 5, the time synchronization deviation between each terminal 11, the access point 12, and the controller 13 is measured in advance, and the time synchronization deviation is taken into consideration as a guard time Tg.

[0022] The guard time Tg can be set in any manner, but the present disclosure will exemplify the following three modes. The largest deviation is set as the guard time Tg (first embodiment). If each terminal 11 and access point 12 constantly notifies the controller 13 of the time synchronization deviation, the controller 13 sets the value that results in the largest time synchronization deviation as the guard time Tg each time scheduling is performed (embodiment example 2). If each terminal 11 and access point 12 constantly communicates the time synchronization deviation to the controller 13, when the controller 13 performs scheduling, it adds the time synchronization deviation of each terminal 11 and access point 12 to the transmission time of each terminal 11 and access point 12 and schedules (embodiment example 3).

[0023] Specifically, the system of the present disclosure has the following configuration. The controller 13 records in advance in the database the guard time Tg or the time synchronization deviation with respect to the packet transmission time of each terminal 11 and the access point 12. Each terminal 11 and access point 12 notifies the controller 13 of the amount of accumulated packets. The controller 13 records the amount of accumulated packets in the database. The controller 13 schedules the packet transmission time and transmission duration based on the guard time or time synchronization deviation recorded in the database and the amount of accumulated packets. The controller 13 notifies each terminal and the access point of the scheduler. Each terminal 11 and access point 12 transmits packets at the packet transmission time set by the scheduler.

[0024] (Example 1) An example of the system configuration of this embodiment is shown in Fig. 6. In this embodiment, each terminal 11, access point 12, and controller 13 are connected by a control signal network 17. The control signal network 17 is any network capable of transmitting and receiving control signals, and may be either wired or wireless.

[0025] Furthermore, in this embodiment, the time synchronization unit TSC measures the maximum value of the time synchronization deviation between each terminal 11 and the access point 12, and stores the maximum value of the time synchronization deviation in the database DB as a guard time Tg.

[0026] The method of storing the guard time Tg in the database DB is arbitrary, but it can be stored in advance in the following manner. Each terminal 11 and access point 12 is equipped with time synchronization units TST and TSA, and the controller 13 is equipped with a time synchronization unit TSC that functions as a control side time synchronization unit. The time synchronization units TST, TSA, and TSC are connected through a time synchronization network 16. The time synchronization units TST and TSA measure the time synchronization deviation between the terminal 11 and the access point 12, and notify the time synchronization unit TSC. The time synchronization unit TSC receives the time synchronization deviation from the time synchronization units TST and TSA, and stores it in the database DB.

[0027] The system of this embodiment is a control system for controlling traffic of a main signal network 15, Each of the terminal 11 and the access point 12 Buffers (FB1, FB2) that store transmission packets for each traffic flow; a device-side transmitting / receiving unit (CTR1, CTR2) that transmits to a controller 13 the amount of transmission packets accumulated for each traffic flow in a buffer (FB1, FB2) and receives from the controller 13 the transmission time and the transmission amount of the transmission packets for each traffic flow; a main signal transmitting unit (MTR1, MTR2) for transmitting the transmission packets for each traffic flow in the buffer (FB1, FB2) to a main signal network 15 according to the transmission time and the transmission amount; Equipped with The controller 13 is a database unit DB for storing the guard time Tg; a control side transceiver CTR3 that receives the stored amount from each of the terminal 11 and the access point 12 and transmits the transmission time and the transmission amount to each of the terminal 11 and the access point 12; a scheduling unit SCH3 that determines the transmission time and the transmission amount of the transmission packet for each traffic flow based on the stored amount; Equipped with.

[0028] In the system of this embodiment, control signals are communicated between the controller 13 and the access point 12 / terminal 11 by a communication means separate from the communication means of the main signal (traffic packets). Specifically, the control signals are transmitted and received between the control signal transmitting / receiving unit CTR1 of the terminal 11 and the control signal transmitting / receiving unit CTR3 of the controller 13, and between the control signal transmitting / receiving unit CTR2 of the access point 12 and the control signal transmitting / receiving unit CTR3 of the controller 13.

[0029] Each terminal 11 and access point 12 periodically notifies the controller 13 of the amount of packets stored in the per-flow buffer units (FB1, FB2) as a control signal. The terminal 11 accumulates packets from each application AP1 in a buffer FB1 for each application (for each flow). A packet amount notification unit NTF1 periodically checks the amount of packets accumulated in each buffer FB1 and notifies the controller 13 of the amount as a control signal via a control signal transmission / reception unit CTR1. In addition, the access point 12 accumulates packets from the upper network device 50 in a buffer FB2 for each application (for each flow). A packet amount notification unit NTF2 periodically checks the amount of packets accumulated in each buffer FB2 and notifies the controller 13 of the amount as a control signal via a control signal transmission / reception unit CTR2. The per-flow buffer unit FB1 may be owned by the application AP1.

[0030] The controller 13 records the notified packet accumulation amount, the terminal 11, the access point 12, and information on the per-flow buffers (FB1, FB2) in the database unit. Based on the information recorded in the database unit DB, the controller 13 determines the transmission time and transmission amount for each buffer, and notifies each terminal 11 and the access point 12 as a control signal. Here, in this embodiment, the interval between transmission times is set to be equal to or longer than the guard time Tg.

[0031] The control signal transmission / reception unit CTR3 of the controller 13 receives control signals from each terminal 11 and access point 12, and organizes the packet accumulation amount, terminal 11, access point 12, and information on per-flow buffers (FB1, FB2) included in the control signals in a database DB.

[0032] 7 is a diagram for explaining an example of information organized in the database DB. This database DB organizes the following four pieces of information: The item number is a serial number for all the buffers (FB1, FB2) of the terminal 11 and the access point 12. The node number is the number of the access point 12 or the terminal 11 . The buffer number is the number of the buffer FB1 held by each terminal 11 or the number of the buffer FB2 held by the access point 12. The packet amount is the amount of packets stored in the buffer having the respective buffer number. For example, item number K+2 is the amount of packets stored in the per-flow buffer unit FB1#2 of terminal 11#1, and the amount is "B12". The guard time Tg is the interval between each transmission time determined by the time synchronization unit TSC.

[0033] The scheduling unit SCH3 of the controller 13 uses a scheduling method described later to determine the transmission time and transmission amount for each buffer from the contents of the database unit DB. At this time, as shown in Fig. 5, the interval between each transmission time is set to be equal to or greater than the guard time Tg. The scheduling unit SCH3 then sets the determined transmission time and transmission amount as a control signal, and transmits them from the control signal transmitting / receiving unit CTR3 to the terminal 11 and the access point 12.

[0034] Each terminal 11 and access point 12 extracts packets stored in the per-flow buffer units (FB1, FB2) at the notified transmission time and transmission amount, and inputs them to the main signal buffer units (MB1, MB2). The main signal transceiver units (MTR1, MTR2) transmit the packets in the main signal buffer units (MB1, MB2) to the main signal network 15.

[0035] 8 is a flowchart illustrating the above-described operation. The control method of this embodiment is a control method for controlling traffic in the main signal network 15, The control method is a transmission control performed by the controller 13 on the terminal 11 and the access point 12 which transmit packets to each other via the main signal network 15, Storing transmission packets for each traffic flow in the buffer units (FB1, FB2) of the terminal 11 and the access point 12 (steps S111, S112, S121, S122); Transmitting to the controller 13 the amount of packets transmitted for each traffic flow stored in each buffer unit (steps S113 and S123); The controller 13 determines a transmission time and a transmission amount of a transmission packet for each traffic flow based on the accumulated amount and the guard time Tg received from the terminal and the access point 12, respectively (steps S131 and S132); Transmitting a transmission time and a transmission amount from the controller 13 to each of the terminal 11 and the access point 12 (step S133); and Transmitting transmission packets for each traffic flow from the buffers of the terminal 11 and the access point 12 to the main signal network 15 according to the transmission time and the transmission amount (steps S114, S124). It is characterized by:

[0036] (Example 2) 6 measure the time synchronization deviation and notify the controller 13. The time synchronization unit TSC in the controller 13 organizes the time synchronization deviations in the terminals 11 and the access point 12 in a database DB.

[0037] 9 is a diagram illustrating an example of information organized in the database DB. In this embodiment, the guard time Tg is a time synchronization deviation T g_A , and the time synchronization deviation T g_1 , T g_N It is.

[0038] In this embodiment, the scheduling unit SCH3 of the controller 13 adjusts the time synchronization deviation T g_A , T g_1 , T g_N The largest value among these is set as the guard time Tg.

[0039] 10 is a flowchart illustrating the operation of the system of this embodiment. The operations (S111 to S114, S121 to S124) of each terminal 11 and the access point 12 are the same as those in the first embodiment, but the operation of the controller 13 is different from that in the first embodiment.

[0040] Specifically, the controller 13 The notified packet accumulation amount in each of the buffer units FB1 and FB2 and the time synchronization deviation of each terminal 11 and the access point 12 are recorded in the database unit DB (step S231); Setting the maximum time synchronization deviation between each terminal 11 and the access point 12 as a guard time Tg (step S232); Based on the amount of packets stored in the database unit DB and the guard time Tg, the scheduling unit SCH3 determines the transmission time and amount of packets stored in each of the buffer units FB1 and FB2 (step S233). notifying each terminal 11 and access point 12 of the packet transmission time and transmission amount of each buffer determined by the scheduling unit SCH3 (step S234); It is characterized by:

[0041] (Example 3) 6 measure the time synchronization deviation and notify the controller 13. The time synchronization unit TSC in the controller 13 organizes the time synchronization deviations in the terminals 11 and the access point 12 in a database DB.

[0042] 11 is a diagram illustrating an example of information organized in the database DB. In this embodiment, the guard time Tg is a time synchronization deviation T g_A , and the time synchronization deviation T g_1 , T g_N It is.

[0043] In this embodiment, the scheduling unit SCH3 of the controller 13 adjusts the time synchronization deviation T between the terminals 11 and the access point 12 at the transmission times of the terminals 11 and the access point 12 every time scheduling is performed. g_A , T g_1 , T g_N For example, when transmitting from buffer number #M of terminal 11#N to access point 12 at transmission time t2, the time synchronization error T g_Nis set as the guard time Tg of the transmission time t2 of the terminal 11#N.

[0044] 12 is a flowchart illustrating the operation of the system of this embodiment. The operations (S111 to S114, S121 to S124) of each terminal 11 and the access point 12 are the same as those in the first embodiment, but the operation of the controller 13 is different from that in the first embodiment.

[0045] Specifically, the controller 13 The notified packet accumulation amount in each buffer unit and the time synchronization deviation of each terminal 11 and the access point 12 are recorded in the database unit DB (step S331); Setting the time synchronization of each terminal 11 and the access point 12 as the respective guard times Tg (step S332); The scheduling unit SCH3 determines the transmission time and transmission amount of the packets stored in each buffer unit based on the packet accumulation amount in the database unit DB and the guard time Tg (step S333); notifying each terminal 11 and access point 12 of the packet transmission time and transmission amount for each buffer determined by the scheduling unit SCH3 (step S334); It is characterized by:

[0046] (Example 4) [Scheduling method] Here, the scheduling method performed by the scheduling unit SCH3 of the controller 13 will be described. [1] Fair scheduling This scheduling method performs calculations in which the bandwidth or time is divided by the total number of per-flow buffers (FB1, FB2) in which packets are stored in the terminal 11 and the access point 12. The parameters are explained below. The number of per-flow buffers in which packets are stored, including the terminal 11 and the access point 12 combined: n Time for 1 cycle: T[sec] Total transmission limit of main signal per cycle: Z [Bytes / sec] Time to send the first stored packet: t start [sec]

[0047] in this case, Transmission volume S of flow unit buffer #J J [Bytes] is

number

number

number

[0048] The order of the per-flow buffers from which transmission starts may be, for example, from the lowest item number arranged in the database unit DB of the controller 13 .

[0049] [2] Scheduling with consideration of bandwidth weighting This scheduling method is determined based on the number of per-flow buffers in which packets are stored, and the amount of packets stored, among the per-flow buffers (FB1, FB2) of terminal 11 and access point 12. The parameters are explained below. Packet accumulation amount in per-flow buffer #J: B J [Bytes] Time for 1 cycle: T[sec] Transmission limit per cycle: Z [Bytes / sec] Time required to transmit all packets stored in all per-flow buffers: T all [sec] The time when the first packet is transmitted from all the packets stored in the per-flow buffer: t start [sec]

[0050] in this case,

number

number

number

number

number

number

number

[0051] In addition, T all If >T, packets that cannot be sent are carried over to the next transmission timing. [Industrial Applicability]

[0052] The present disclosure can be applied to the information and communications industry. [Explanation of symbols]

[0053] 11: Terminal 12: Access point 13: Controller 15: Main signal network 50: Upper network device

Claims

1. A control system for controlling traffic in a wireless network, comprising: a terminal and an access point for transmitting packets to each other via the wireless network; A controller that performs transmission control on the terminal and the access point; It is equipped with The controller: Obtaining a time synchronization deviation between the terminal and the access point; determining a bandwidth control value for each traffic flow based on at least a required bandwidth for each traffic flow notified from the terminal; notifying the terminal and the access point of a transmission time corresponding to the bandwidth control value and the deviation of the time synchronization, and a transmission amount corresponding to the bandwidth control value; A control system comprising:

2. Each of the terminal and the access point a buffer for storing transmission packets for each traffic flow; an apparatus-side transmitting / receiving unit that transmits an accumulated amount of the transmission packets for each traffic flow accumulated in the buffer to the controller as the required bandwidth, and receives from the controller a transmission time and a transmission amount of the transmission packets for each traffic flow as the bandwidth control value; a main signal transmission unit that transmits the transmission packets for each traffic flow in the buffer to the wireless network in accordance with the transmission time and the transmission amount; Equipped with The controller: a database unit for storing a time synchronization deviation between the terminal and the access point; a control side transceiver that receives the storage amount as the required bandwidth from each of the terminal and the access point, and transmits the transmission time and the transmission amount as the bandwidth control value to each of the terminal and the access point; a scheduling unit that determines the transmission amount of the transmission packets for each traffic flow based on the accumulated amount, and determines the transmission time of the transmission packets for each traffic flow based on the accumulated amount and the time synchronization deviation; 2. The control system of claim 1, further comprising:

3. the controller includes a control side time synchronization unit that sets a guard time, which is an interval of the transmission time, by using a time synchronization difference between the terminal and the access point, and stores the guard time in the database unit; The scheduling unit sets the interval of the transmission times to be equal to or longer than the guard time.

3. The control system of claim 2.

4. Each of the terminal and the access point includes a time synchronization unit that measures a time synchronization deviation between the terminal and the access point and notifies the controller; the controller includes a control side time synchronization unit that stores a time synchronization deviation between the terminal and the access point in the database unit for each of the terminal and the access point; The scheduling unit reads out the maximum value of the time synchronization deviation from the database unit every time the bandwidth control value is determined, and sets the interval of the transmission times to be equal to or greater than the maximum value of the time synchronization deviation.

3. The control system of claim 2.

5. Each of the terminal and the access point includes a time synchronization unit that measures a time synchronization deviation between the terminal and the access point and notifies the controller; the controller includes a control side time synchronization unit that stores a time synchronization deviation between the terminal and the access point in the database unit for each of the terminal and the access point; The scheduling unit reads out from the database a time synchronization deviation of the terminal and the access point to which the bandwidth control value is assigned, and sets a transmission time according to the bandwidth control value and the time synchronization deviation for each of the terminal and the access point.

3. The control system of claim 2.

6. A method for controlling traffic in a wireless network, comprising: The control method includes a transmission control performed by a controller on a terminal and an access point that transmit packets to each other via the wireless network, Obtaining a time synchronization deviation between the terminal and the access point; A control method characterized by determining a bandwidth control value for each traffic flow based on the required bandwidth for each traffic flow notified at least from the terminal, and notifying the terminal and the access point of the bandwidth control value, a transmission time corresponding to the time synchronization deviation, and a transmission amount corresponding to the bandwidth control value.

7. A controller for controlling traffic in a wireless network, comprising: The controller is a device that performs transmission control on terminals and access points that transmit packets to each other via the wireless network, Obtaining a time synchronization deviation between the terminal and the access point; determining a bandwidth control value for each traffic flow based on at least a required bandwidth for each traffic flow notified from the terminal; A controller comprising a function of notifying the terminal and the access point of a transmission time corresponding to the bandwidth control value and the deviation of the time synchronization, and a transmission amount corresponding to the bandwidth control value.

8. A program for causing a computer to function as the controller according to claim 7.

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