Patent Application
20240397386
The present disclosure relates to a communication system, a control method, a controller, and a program for wirelessly transmitting and receiving a control signal.
In recent years, there have been studies on accommodating a plurality of services and applications having various network requirements on the same network infrastructure. For this purpose, it is necessary to ensure the quality required by each service and application accommodated on the same NW in an end-end section of “terminal to terminal” or “terminal to application server”.
The end-end sections of a network can be divided into wireless and wired sections. Among those, in wireless sections, there is a priority control function called Enhanced Distributed Channel Access (EDCA) of IEEE 802.11 as an existing technology (see, for example, Non Patent Literature 1 and Non Patent Literature 2).
EDCA is control on a terminal (destination) basis, and while it is difficult to perform control on a traffic flow basis to enable quality control on a service and application basis, quality control on a service and application basis can be realized by applying a quality control technology (see, for example, Non Patent Literature 3) by centralized control independent of a wireless network.
The terminal #N transmits the packet amount b newly accumulated in the buffer #M held by the terminal #N to the controller as an accumulated packet amount notification I in each time t. Specifically, the terminal #N transmits information indicating that the packet amount accumulated in the buffer #M is zero in accumulated packet amount notification I0 (there is no packet in the buffer until transmission of I1), the packet amount is 1 in accumulated packet amount notification I1 (one packet b is accumulated in the buffer #M at a cycle t1), the packet amount is 3 in accumulated packet amount notification I2 (two packets b are accumulated in buffer #M at a cycle t2), the packet amount is 4 in accumulated packet amount notification I3 (one packet b is accumulated in buffer #M at a cycle t3), and the packet amount is 5 in accumulated packet amount notification I4 (one packet b is accumulated in buffer #M at a cycle t4).
Thereafter, the terminal #N repeats the above operation at the cycles t1.
The controller integrates the accumulated packet amount notification I that has arrived in period Tc, and recognizes that five packets are accumulated in the buffer #M of the terminal #N. Then, the controller schedules the transmission timing and the transmission time for five packets for the buffer #M of the terminal #N. The controller transmits a schedule Sc to the terminal #N. Further, the transmission timing is “a timing to start packet transmission”, and the transmission time is “a temporal length in which packet transmission is permitted”.
The terminal #N transmits five packets from the buffer #M to the access point #K at the timing indicated by the schedule Sc at the indicated speed (step Bt).
Further, although
On the other hand, in a case where the control signal is made wireless, the occurrence of packet loss due to an external factor increases more than in a case where the control signal is made wired, and there is a possibility of an event like that illustrated in
That is, situations to which EDCA can be applied increase when a control signal for quality control is made wireless, but there is a problem that communication quality may deteriorate due to packet loss of the control signal.
Therefore, in order to solve the above problems, it is an object of the present invention to provide a communication system, a control method, a controller, and a program capable of preventing deterioration in communication quality due to wireless control signals for quality control.
In order to achieve the above object, the communication system according to the present invention transmits the same control signal a plurality of times.
Specifically, a communication system according to the present invention is a communication system that controls traffic of a wireless network, the communication system including a terminal and an access point that transmit a packet to each other via the wireless network, and a controller that transmits and receives a control signal to and from the terminal and the access point via the wireless network, in which each of the terminal and the access point transmits an accumulated packet amount notification that is an amount of packets accumulated in a buffer having the same content a plurality of times when the accumulated packet amount notification is transmitted to the controller as the control signal, and the controller determines a schedule for transmitting the packet based on the content of the accumulated packet amount notification received from at least one of the terminal and the access point and transmits the schedule having the same content a plurality of times when the schedule is transmitted to each of the terminal and the access point as the control signal.
In addition, a control method according to the present invention is a control method for controlling traffic of a wireless network including a terminal and an access point that transmit a packet to each other via the wireless network and a controller that transmits and receives a control signal to and from the terminal and the access point via the wireless network, the control method including transmitting, by each of the terminal and the access point, an accumulated packet amount notification that is an amount of packets accumulated in a buffer having the same content a plurality of times when the accumulated packet amount notification is transmitted to the controller as the control signal, and determining, by the controller, a schedule for transmitting the packet based on the content of the accumulated packet amount notification received from at least one of the terminal and the access point and transmitting the schedule having the same content a plurality of times when the schedule is transmitted to the terminal and the access point as the control signal.
Furthermore, a controller according to the present invention is a controller that transmits and receives a control signal to and from a terminal and an access point via a wireless network, the terminal and the access point transmitting a packet to each other via the wireless network, the controller including a reception unit that receives, as the control signal, an accumulated packet amount notification that is an amount of packets accumulated in each buffer from at least one of the terminal and the access point, a scheduling unit that determines a schedule for transmitting the packet based on the content of the accumulated packet amount notification, and a transmission unit that transmits the schedule having the same content a plurality of times when the schedule is transmitted to each of the terminal and the access point as the control signal.
Since the transmission side transmits the control information (the accumulated packet amount notification and the schedule) having the same content a plurality of times, even if packet loss occurs during transmission, the reception side can receive any one piece of the control information transmitted a plurality of times. Thus, the present invention can provide a communication system, a control method, a controller, and a program capable of preventing deterioration in communication quality due to wireless control signals for quality control.
The load of reading all control information transmitted a plurality of times on the reception side is heavy. Thus, it is preferable that a sequence number be assigned to the accumulated packet amount notification and the schedule, the controller discard the accumulated packet amount notification whose sequence number is the same as that of the previous accumulated packet amount notification, and the terminal and the access point discard the schedule whose sequence number is the same as that of the previous schedule.
The present invention is a program for causing a computer to function as the controller. A data collection device of the present invention can also be implemented by a computer and a program, and the program can be recorded in a recording medium or provided through a network.
Further, the above inventions can be combined where possible.
The present invention can provide a communication system, a control method, a controller, and a program capable of preventing deterioration in communication quality due to wireless control signals for quality control.
Embodiments of the present invention will be described with reference to the accompanying drawings. The embodiments described below are examples of the present invention, and the present invention is not limited to the following embodiments. Further, components having the same reference numerals in the present specification and the drawings indicate the same components.
Since the controller 13 calculates a schedule for each traffic flow by using control information of each traffic flow (see, for example, Non Patent Literature 3), the communications system 301 can ensure a band for each traffic flow.
Further, the communication system 301 in
The communication system 301 connects each terminal 11 and an access point 12 to the controller 13, and performs accumulating packets in buffer units (FB1 and FB2) for each traffic flow in each terminal 11 and the access point 12 or in a buffer in an application, notifying the controller 13 of the accumulated packet amount in advance, determining a transmission timing and a transmission amount for each traffic flow in a scheduling unit SCH3 of the controller 13, causing the controller 13 to notify each terminal 11 and the access point 12 of a schedule (the transmission timing and the transmission amount) a plurality of times, and transmitting packets according to the transmission timing and the transmission amount of which each terminal 11 and the access point 12 are notified.
Further, timings of each terminal 11, the access point 12, and the controller 13 are assumed to be synchronized using NTP, PTP, or the like.
Specifically, the communication system 301 is a communication system that controls traffic of the wireless network 15, and includes the terminals 11 and the access point 12 that mutually transmit packets via the wireless network 15 #2, and the controller 13 that transmits and receives a control signal to and from the terminals 11 and the access point 12 via a wireless network 15 #1, in which each of the terminals 11 and the access point 12 transmit an accumulated packet amount notification, which is of a packet amount accumulated in the buffer units (FB1 and FB2) having the same content a plurality of times when transmitting the accumulated packet amount notification to the controller 13 as the control signal, and the controller 13 determines a schedule for transmitting the packets based on the content of the accumulated packet amount notification received from at least one of the terminal 11 and the access point 12, and transmits the schedule having the same content a plurality of times when transmitting the schedule as the control signal to each of the terminals 11 and the access point 12.
The communication system 301 communicates a control signal between the controller 13 and the access point 12/terminals 11 using a communication means (wireless network 15 #1) that is different from a communication means (wireless network 15 #2) for the main signal (packets in traffic). Specifically, the control signal is transmitted and received between a control signal transmission/reception unit CTR1 of the terminal 11 and a control signal transmission/reception unit CTR3 of the controller 13, and between a control signal transmission/reception unit CTR2 of the access point 12 and the control signal transmission/reception unit CTR3 of the controller 13.
Each terminal 11 and the access point 12 periodically notify the controller 13 of the packet amounts accumulated in the per-flow buffer units (FB1 and FB2) in units of flows as a control signal via the wireless network 15 #1.
The terminal 11 accumulates packets from each application AP1 in the buffer unit FB1 for each application (for each flow). A packet amount notification unit NTF1 periodically checks the packet accumulation amount of each buffer unit FB1 and notifies the controller 13 of it as a control signal via the control signal transmission/reception unit CTR1.
In addition, the access point 12 accumulates packets from an upper network device 50 in the buffer unit FB2 for each application (for each flow). A packet amount notification unit NTF2 periodically checks the packet accumulation amount of each buffer unit FB2 and notifies the controller 13 of it as a control signal via the control signal transmission/reception unit CTR2.
Further, the per-flow buffer unit FB1 may be owned by the application AP1.
Here, it is assumed that each terminal 11 and the access point 12 notify the controller 13 of the accumulated packet amount at regular cycles t. Each terminal 11 and the access point 12 transmit the same accumulated packet amount notification n times at one cycle (n is an integer equal to or greater than 2). Thus, the time required to transmit the accumulated packet amount notification n times is equal to or less than a cycle t.
The controller 13 records the notified packet accumulation amount and information of the terminals 11, the access point 12, and the per-flow buffers (FB1 and FB2), and determines a transmission timing and a transmission amount (schedule) for each buffer unit based on the above. Then, the controller 13 notifies each terminal 11 and the access point 12 of the schedule as a control signal via the wireless network 15 #1.
The control signal transmission/reception unit CTR3 of the controller 13 receives the control signal from each terminal 11 and the access point 12, and organizes the packet amount accumulated in each of the per-flow buffers (FB1 and FB2) in a database DB.
An item number is a serial number for all of the buffer units (FB1 and FB2) of the terminals 11 and the access point 12.
A node number is a number of the access point 12 or a terminal 11.
A buffer number is a number of the buffer unit FB1 held by each terminal 11 or a number of the buffer unit FB2 held by the access point 12.
A packet amount is a packet accumulation amount held by the buffer unit with its buffer number.
For example, an item number K+2 is a packet accumulation amount of a per-flow buffer unit FB1 #2 held by a terminal 11 #1, meaning that the amount thereof is “B12”.
The scheduling unit SCH3 of the controller 13 determines the transmission timing and the transmission amount for each buffer unit based on the content of the database unit DB using a scheduling method disclosed in Non Patent Literature 3. Then, the scheduling unit SCH3 uses the determined schedule as a control signal and transmits the control signal to the terminal 11 and the access point 12 from the control signal transmission/reception unit CTR3.
Here, it is assumed that the controller 13 notifies each terminal 11 and the access point 12 of the schedule at regular cycles Tc. The controller 13 transmits the same schedule m times (m is an integer equal to or greater than 2). Thus, the time required to transmit the same schedule m times is equal to or less than the cycle Tc.
Each terminal 11 and the access point 12 extract packets accumulated in the per-flow buffer units (FB1 and FB2) at the transmission timing and transmission amount of the notified schedule, and inputs the packets to main signal buffer units (MB1 and MB2). Main signal transmission/reception units (MTR1 and MTR2) transmit packets of the main signal buffer units (MB1 and MB2) to the wireless network 15 #2.
Specifically, the terminal 11 #N transmits information indicating that the packet amount accumulated in the buffer unit FB1 #M is zero in accumulated packet amount notification I0 (there is no packet in the buffer unit until transmission of I1), the packet amount is 1 in accumulated packet amount notification I1 (one packet b is accumulated in the buffer unit #M at a cycle t1), the packet amount is 3 in accumulated packet amount notification I2 (two packets b are accumulated in the buffer unit #M at a cycle t2), the packet amount is 4 in accumulated packet amount notification I3 (one packet b is accumulated in the buffer unit #M at a cycle t3), and the packet amount is 5 in accumulated packet amount notification I4 (one packet b is accumulated in the buffer unit #M at a cycle t4).
Then, the terminal 11 #N transmits the accumulated packet amount notification Ii n times (n=5 in this example) at each cycle ti.
Here, it is assumed that packet loss occurs during transmission of the accumulated packet amount notification I4. The accumulated packet amount notification I4 in which the packet loss has occurred does not reach the controller 13, but the same notification is transmitted n times, and thus the controller 13 can receive any of the notifications. Therefore, the controller 13 can perform scheduling with accurate information.
The controller 13 integrates the accumulated packet amount notification Ii delivered in the period Tc, and recognizes that five packets are accumulated in the buffer unit FB1 #M of the terminal 11 #N. Then, the controller 13 schedules the transmission timing and the transmission time for 5 packets for the buffer unit FB1 #M of the terminal 11 #N. The controller 13 transmits the schedule Sc to the terminal 11 #N.
The terminal 11 #N transmits the five packets from the buffer unit FB1 #M to the access point 12 #K at the timing indicated by the schedule Sc at an indicated speed (step Bt).
Further, although
In this example, the operations up to the accumulated packet amount notification I4 are the same as those described in
The controller 13 integrates the accumulated packet amount notification Ii delivered in the period Tc, and recognizes that five packets are accumulated in the buffer unit FB1 #M of the terminal 11 #N. Then, the controller 13 schedules the transmission timing and the transmission time for 5 packets for the buffer unit #M of the terminal 11 #N. The controller 13 transmits the schedule Sc to the terminal 11 #N m times (m=4 in this example).
Further, the terminal 11 #N receives the same schedule a plurality of times, and in such a case, the schedule may be updated each time the schedule is received.
In addition, in this drawing, in order to avoid complication of the drawing, description of transmission of the schedule Sc scheduled at the cycle before the cycle Tc is omitted.
Here, it is assumed that packet loss has occurred during transmission of the schedule Sc. Although the schedule Sc in which the packet loss has occurred does not reach the terminal 11 #N, the terminal 11 #N can receive any schedule Sc since the same schedule Sc has been transmitted m times. Therefore, the terminal 11 #N can transmit packets with accurate information (step Bt).
In addition, in the control method described with reference to
Further, although
A configuration of a communication system according to the present embodiment is the same as that of
In the present communication system, a sequence number is assigned to the accumulated packet amount notification and the schedule, the controller 13 discards the accumulated packet amount notification whose sequence number is the same as that of the previous accumulated packet amount notification (Steps S130a and S130b), and the terminal 11 and the access point 12 discard the schedule whose sequence number is the same as that of the previous schedule (steps S113a, S123a, and S150).
When the controller 13 reads the accumulated packet amount notification from each terminal 11 and the access point 12 in a short time, and when each terminal 11 and the access point 12 read the schedule from the controller 13 in a short time, there is concern that a load increases in each device and the quality such as throughput may deteriorate.
Therefore, a sequence number is assigned to the accumulated packet amount notification and the schedule. For example, a sequence number may be embedded in header information of packets of a notification and a schedule.
Each terminal 11, the access point 12, and the controller 13 determine whether it is a notification that the sequence number is updated (accumulated packet amount notification or schedule) (steps S130a, S123a, and S113a). Then, the terminal 11, the access point 12, and the controller 13 read only the updated notification, or the content of the notification (steps S131, S124, and S114) and discard the others (steps S130b and S150).
According to the control method of the present embodiment, even if the accumulated packet amount notification and the schedule are transmitted a plurality of times, degradation of the quality such as throughput can be avoided.
The controller 13 can also be realized by a computer and a program, and the program can be recorded in a recording medium or provided through a network.
The network 135 is a data communication network. The network 135 may be a private network or a public network, and may include any or all of (a) a personal area network, for example, covering a room, (b) a local area network, for example, covering a building, (c) a campus area network, for example, covering a campus, (d) a metropolitan area network, for example, covering a city, (e) a wide area network, for example, covering an area connected across boundaries of cities, rural areas, or countries, and (f) the Internet. Communication is performed by using electronic signals and optical signals via the network 135.
The computer 105 includes a processor 110 and a memory 115 connected to the processor 110. In the present specification, although the computer 105 is represented as a standalone device, the computer is not limited thereto, and may be connected to other devices, which are not illustrate, in a distributed processing system.
The processor 110 is an electronic device including a logic circuitry that responds to a command and executes the command.
The memory 115 is a tangible computer-readable storage medium in which a computer program is encoded. In this regard, the memory 115 stores data and commands, that is, program codes, that are readable and executable by the processor 110 to control operations of the processor 110. The memory 115 can be implemented by a random access memory (RAM), a hard drive, a read-only memory (ROM), or a combination thereof. One of the components of the memory 115 is a program module 120.
The program module 120 includes commands for controlling the processor 110 to perform processes described in the present specification. In the present specification, although it is described that operation is executed by the computer 105, a method, a process, or a sub-process thereof, the operation is actually executed by the processor 110.
In the present specification, the term “module” is used to refer to functional operation that may be embodied as a stand-alone component or as an integrated configuration of a plurality of sub-components. Thus, the program module 120 can be implemented as a single module or as a plurality of modules that operate in cooperation with each other. Further, in the present specification, although the program module 120 is described as being installed in the memory 115 and thus implemented in software, the program module 120 can be implemented in any of hardware (for example, an electronic circuit), firmware, software, or a combination thereof.
Although the program module 120 is illustrated as already being loaded into the memory 115, the program module 120 may be configured to be provided on a storage device 140 so as to be subsequently loaded into the memory 115. The storage device 140 is a tangible computer-readable storage medium that stores the program module 120. Examples of the storage device 140 include a compact disk, a magnetic tape, a read-only memory, an optical storage medium, a hard drive or a memory unit including a plurality of parallel hard drives, and a universal serial bus (USB) flash drive. Alternatively, the storage device 140 may be a random access memory or another type of electronic storage device provided in a remote storage system which is not illustrated and connected to the computer 105 via the network 135.
The system 100 further includes a data source 150A and a data source 150B which are collectively referred to herein as a data source 150 and are communicatively connected to the network 135. In practice, the data source 150 may include any number of data sources, that is, one or more data sources. The data source 150 may include unstructured data and may include social media.
The system 100 further includes a user device 130 operated by a user 101 and connected to the computer 105 via the network 135. Examples of the user device 130 include an input device, such as a keyboard or a voice recognition subsystem, for enabling the user 101 to input information and command selections to the processor 110. The user device 130 further includes an output device such as a display device, a printer, or a speech synthesizer. A cursor control unit such as a mouse, a trackball, or a touch-sensitive screen allows the user 101 to manipulate a cursor on the display device to input further information and command selections to the processor 110.
The processor 110 outputs a result 122 of execution of the program module 120 to the user device 130. Alternatively, the processor 110 can provide the output to a storage device 125 such as a database or a memory or to a remote device, which is not illustrated, via the network 135.
For example, a program for performing steps S131 to S133 in the flowchart of
The term “include . . . ” or “including . . . ” specifies that the mentioned features, integers, steps, or components are present, but should be understood as not excluding the presence of one or more other features, complete bodies, steps, or components, or groups thereof. The terms “a” and “an” are indefinite articles and therefore do not exclude embodiments including a plurality of objects.
Further, the present invention is not limited to the above embodiments, and various modifications can be made without departing from the gist of the present invention. In short, the present invention is not limited to the specific embodiments, and in the implementation stage, the components may be modified and embodied without departing from the scope of the present invention.
In addition, various inventions can be made by appropriately combining a plurality of components disclosed in the above embodiments. For example, some components may be deleted from all the components illustrated in the embodiments. Furthermore, components in different embodiments may be appropriately combined.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP2021/034076 | 9/16/2021 | WO |
