KR101923850B1 - Wireless communication apparatus, wireless communication method, and wireless communication program - Google Patents

Abstract

In the wireless master apparatus N201, the wireless scheduling unit 16 transmits real-time data and real-time data within a communication cycle for performing wireless communication with a wireless slave device N300 that transmits real-time data and non- And causes the wireless slave device N300 to transmit real-time data in the real-time data period, and when a communication cycle remains at the time when transmission of the real-time data by the wireless slave device N300 is completed, Time data period, and causes the wireless slave device N300 to transmit non-real-time data in the non-real-time data period.

Description

Wireless communication apparatus, wireless communication method, and wireless communication program

The present invention relates to wireless communications. The present invention relates to wireless communication, for example in an industrial network.

As described in the following Non-Patent Document 1, one master device and a plurality of slave devices are connected in a network called a field network among industrial networks.

For example, the master device is a controller, and the slave device is various I / O (input / output) devices or measuring devices.

Then, cyclic communication is performed at a predetermined time interval between the master device and the plurality of slave devices.

On the other hand, for the purpose of reducing the cost of laying out a wired network, wireless networking is required.

It is uncomfortable to use a special device or a license to make the network wireless.

Therefore, it is possible to reduce hardware procurement cost and development cost by realizing network wirelessization in accordance with the existing wireless LAN standard (Non-Patent Document 2).

In the industrial network, constant periodicity is required, and the master device is required to connect with a plurality of slave devices.

For this reason, schedule management for preventing collision in the radio section is required.

In the wireless LAN standard, the HCCA (Hybrid Coordination Function Controlled Channel Access) scheme is described in the IEEE802.11e standard (Non-Patent Document 3).

In the HCCA scheme, the access point concentrates control of data transmission between a plurality of wireless LAN terminals, thereby realizing QoS (Quality of Service) among a plurality of wireless LAN terminals sharing the same channel.

It is conceivable that the HCCA system is adopted in the industrial network for wirelessization and the devices existing in the industrial network are polled by wireless communication in order.

Non-Patent Document 1: Introduction to Industrial Ethernet (registered trademark) May 2009 CQ Publishing Co. Non-Patent Document 2: IEEE Std 802.11TM-2012 "Part 11: Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) Specifications" IEEE Std 802.11eTM-2005 "Part 11: Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) specifications Amendment 8: Medium Access Control (MAC) Quality of Service Enhancements"

In the industrial network, it is required that a small amount of real-time data (cyclic data transmission in the CC-Link IE field network or real-time channel in PROFINET) be continuously communicated between the master device and the slave device at regular intervals.

Also, in an industrial network, when non-real-time data (transient transmission in the CC-Link IE field network or non-real-time channel in PROFINET) exists, Data is communicated between the master device and the slave device.

It is possible to predict in advance the allocation time of the real-time data and the allocation time of the non-real-time data in the industrial network by wire communication in which an error hardly occurs.

It is also possible to determine in advance which slave device among a plurality of slave devices will communicate non-real-time data with the master device at a certain timing.

However, when the industrial network is made wireless, there are the following problems.

(1) Since a communication error frequently occurs, it is necessary to modify the schedule for transmitting and receiving real-time data every time a communication error occurs, and it is necessary to notify the slave device of the modification of the schedule from the master device.

(2) Due to the modification of the schedule, communication for inquiring about the data amount of the real-time data held by each slave device from the master device to each slave device occurs in a large amount, resulting in a decrease in communication efficiency (16 slave devices , And when the number is increased to 32, the communication efficiency is further deteriorated).

With these problems, there arises a problem that the cycle for communication between the master device and the slave device increases, and a problem that the frequency resources are unnecessarily consumed.

The main object of the present invention is to solve these problems, and it is a main object of the present invention to realize high reliability and high communication efficiency in wireless communication in which communication errors tend to occur.

The wireless communication apparatus according to the present invention is a wireless communication apparatus for wireless communication with a wireless communication device that transmits first data and second data having lower priority than the first data, The first data period is allocated to the first data period and the first data period is transmitted to the wireless communication device in the first data period, and when the transmission of the first data by the wireless communication device is completed, A second data period for transmitting the second data, and for transmitting the second data to the wireless communication device in the second data period, And a second data period in which the second data period is different from the second data period, And a wireless receiver for receiving data.

In the present invention, a first data period for transmitting first data is allocated within a wireless communication period, and when a wireless communication period remains at a point of time when transmission of the first data is completed, And a second data period for transmission of data.

Therefore, according to the present invention, it is possible to reliably complete the transmission of the first data within the wireless communication period, thereby realizing high reliability and high communication efficiency in wireless communication.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a diagram showing an example of an industrial network by wireless communication and an example of an industrial network by conventional wired communication according to the first embodiment; Fig.
2 is a diagram showing an example of a communication link between a wireless master device and a wireless slave device;
3 is a diagram showing an example of a communication sequence in an industrial network according to the first embodiment;
4 is a diagram showing a functional configuration example of a wireless master device and a wireless slave device according to the first embodiment;
5 is a diagram showing an example of a communication sequence in a real-time data period according to the first embodiment;
6 is a diagram showing an example of a communication sequence in a non-real-time data period according to the first embodiment;
7 is a flowchart showing an operation example of a radio master device according to the first embodiment;
8 is a flowchart showing an operation example of a wireless master device according to the first embodiment;
9 is a flowchart showing an operation example of a wireless slave device according to the first embodiment;
10 is a diagram showing a functional configuration example of a wireless master device and a wireless slave device according to the second embodiment;
11 is a diagram showing a format of an 802.11 Ack frame.
12 is a diagram showing the format of an 802.11 PPDU frame.
13 is a diagram showing a method of notifying the number of data held in the wireless slave device in the Duration field according to the second embodiment;
14 is a diagram showing a method of notifying the number of data held in the wireless slave device in the SERVICE field according to the second embodiment;
15 is a diagram showing a hardware configuration example of a wireless master device and a wireless slave device according to the first and second embodiments;

Embodiment 1

In this embodiment and the following embodiments, in the industrial network, when real-time data is continuously transmitted and received by a wireless communication between a master device and a slave device at regular intervals, And a transmitting / receiving unit for transmitting / receiving data.

In the present embodiment and the subsequent embodiments, the cycle for transmitting and receiving data between the master device and the slave device is fixed.

In the present embodiment and subsequent embodiments, a real-time data period is set at the beginning of the period, and a non-real-time data period is set after the real-time data period.

The fluctuation due to the communication error is absorbed by stretching the length of the real-time data period.

If there is a remaining time in the cycle after the real-time data period is completed, the remaining time is allocated to the non-real-time data period.

By doing so, punctuality and communication resources can be made effective in the present embodiment and subsequent embodiments.

*** Description of configuration ***

Fig. 1 shows an example of a system configuration of an industrial network by conventional wired communication and an example of a system configuration of an industrial network by wireless communication according to the present embodiment.

In the industrial network by wire communication, the master device N1, the slave device (1) N101, the slave device (2) N102, the slave device (N) 3, and the slave device (m) N104 are wired.

When it is not necessary to distinguish between the slave device N101, the slave device N102, the slave device N103 and the slave device m104, each slave device is collectively referred to as a slave device N100 .

In the industrial network by wireless communication, the wireless master device N201 is connected to the master device N1.

The wireless master device N201 is also referred to as a wireless master.

The master device N1 is, for example, a controller of an industrial network.

The wireless slave device N101 is connected to the slave device N101 and the wireless slave device N102 is connected to the slave device N102 and the slave device N103 is connected to the wireless slave device 3 ) N303, and the slave device (m) N104 is connected to the wireless slave device (m) N304.

When it is not necessary to distinguish between the wireless slave device 1 N301, the wireless slave device 2 N302, the wireless slave device 3 N303 and the wireless slave device m304, each wireless slave device is collectively referred to as wireless Slave device N300.

The wireless slave device N300 is also referred to as a wireless slave.

The slave device N100 is, for example, various types of IO devices and measuring devices in an industrial network.

The master device N1 and the slave device N100 can communicate with each other through the wireless master device N201 and the wireless slave device N300 to exchange data equivalent to that of the wired communication.

In Fig. 1, the connection topology of the industrial network by wire communication is a line type (daisy chain type), and the connection topology of the industrial network by wireless communication is one star N type ), But this difference is not an essential difference.

The connection topology of the industrial network by wire communication may be a star type, a bus type, or a ring type.

The connection topology of the industrial network by wireless communication may be different from that shown in Fig.

The wireless master apparatus N201 corresponds to an example of a wireless communication apparatus and the wireless slave apparatus N300 corresponds to an example of a wireless communication apparatus.

The operation sequence performed by the wireless master device N201 and the operation sequence performed by the wireless slave device N300 correspond to examples of the wireless communication method and the wireless communication program, respectively.

Next, communication between the master device N1 and the slave device N100 via the wireless master device N201 and the wireless slave device N300 will be described with reference to FIG.

2 shows an example in which there are three sets of the slave device N100 and the wireless slave device N300.

The master device N1 and the wireless master device N201 are connected by a wire.

Similarly, the slave device N100 and the wireless slave device N300 are connected by a wire.

That is, the master device N1 and the wireless master device N201 are connected by the wired communication link L1.

Further, the slave device 1 (N101) and the wireless slave device (N101) are connected by a wire communication link L31.

Further, the slave device 2 (N2) and the wireless slave device (N2) N2 are connected by a wired communication link L32.

The slave device 3 103 and the wireless slave device 3 303 are connected by a wired communication link L33.

The wireless master device N201 and the wireless slave device N300 are wirelessly connected.

That is, the wireless master device N201 and the wireless slave device N301 are connected by the wireless communication link L21.

The wireless master device N201 and the wireless slave device (N2) N2 are connected by a wireless communication link L22.

The wireless master device N201 and the wireless slave device (N3) N3 are connected by a wireless communication link L23.

Since the wired communication links L1 and L31 to L33 exist independently, communication can be performed at the same time between the master device N1 and the wireless master device N201, and between the slave device N100 and the wireless slave device N300.

On the other hand, only one communication is possible between the wireless master device N201 and the wireless slave device N300 at the same time.

Further, although the wireless master device N201 grasps the communication status in the wireless communication links L21 to L23, the wireless slave device N300 can not grasp the communication status of the wireless communication links L21 to L23.

When it is not necessary to distinguish the wireless communication links L21 to L23, the wireless communication links L21 to L23 are collectively referred to as a wireless communication link L20.

When it is not necessary to distinguish the wired communication links L31 to L33, the wired communication links L31 to L33 are collectively referred to as a wired communication link L30.

Fig. 4 shows an example of the functional configuration of the radio master device N201 and radio slave device N300 according to the present embodiment.

4, the wireless master device N201 includes a wired communication unit 11, a priority queue management unit 12, a wireless communication unit 13, and a storage unit 17. The wireless communication unit 13 includes a wireless transmission unit A radio receiver 14, a radio receiver 15 and a radio scheduler 16.

The wireless master device N201 includes hardware such as a processor 901, a storage device 902, a wired communication interface 903, and a wireless communication interface 904 as shown in Fig.

The storage unit 17 is realized by the storage device 902. [

A program for realizing the functions of the wired communication unit 11, the priority queue management unit 12, the wireless transmission unit 14, the wireless reception unit 15, and the wireless scheduling unit 16 is stored in the storage device 902 .

The processor 901 executes these programs to perform operations of the wired communication unit 11, the priority queue management unit 12, the radio transmission unit 14, the radio reception unit 15 and the radio scheduling unit 16 .

15, the processor 901 executes a program that realizes the functions of the wired communication unit 11, the priority queue management unit 12, the wireless transmission unit 14, the wireless reception unit 15, and the wireless scheduling unit 16 And the like.

The wired communication interface 903 performs wired communication with the master device N1.

The wireless communication interface 904 performs wireless communication with the wireless slave device N300.

The wireless slave device N300 includes a wired communication unit 21, a priority queue management unit 22, a wireless communication unit 23 and a storage unit 27. The wireless communication unit 23 includes a wireless transmission unit 24 and a wireless reception unit 25).

The wireless slave device N300 includes hardware such as a processor 905, a storage device 906, a wired communication interface 907, and a wireless communication interface 908 as shown in Fig.

The storage unit 27 is realized by the storage device 906. [

The memory device 906 stores a program for realizing the functions of the wired communication unit 21, the priority queue management unit 22, the radio transmission unit 24, and the radio reception unit 25. [

The processor 905 executes these programs to perform operations of the wired communication unit 21, the priority queue management unit 22, the wireless transmission unit 24, and the wireless reception unit 25, which will be described later.

15 schematically shows a state in which the processor 905 executes a program for realizing the functions of the wired communication unit 21, the priority queue management unit 22, the radio transmission unit 24, and the radio reception unit 25. [ Respectively.

The wired communication interface 907 performs wire communication with the slave device N100.

The wireless communication interface 908 performs wireless communication with the wireless master device N201.

*** Description of operation ***

In the wireless master device N201, the wired communication unit 11 receives data to be transmitted from the master device N1 to the slave device N100 via the wired communication link L1 by using the wired communication interface 903.

The wired communication unit 11 transmits the data transmitted from the slave device N100 to the master device N1 via the wired communication link L1 by using the wired communication interface 903. [

The data transmitted and received by the wired communication unit 11 is provided with a priority level.

In the present embodiment, an example in which the wired communication unit 11 transmits and receives real-time data and non-real-time data will be described.

In this embodiment, the priority of real-time data is high and the priority of non-real-time data is lower than the priority of real-time data.

The real-time data corresponds to the example of the first data, and the non-real-time data corresponds to the example of the second data.

The priority queue management unit 12 manages queues provided for each degree of priority.

The priority queue is provided in the storage unit 17, which is a storage area of data.

That is, the storage unit 17 stores real-time data and non-real-time data for each priority degree.

The priority queue management unit 12 stores the received real-time data in a queue of high priority when real-time data is received, and stores the received non-real-time data in a queue of a high priority if the real- .

In addition, the queue management unit 12 for each priority reads real-time data from a queue with a high priority and reads non-real-time data from a queue with a low priority.

The wireless communication unit 13 performs wireless communication with the wireless slave device N300.

The wireless communication unit 13 includes a wireless transmission unit 14, a wireless reception unit 15, and a wireless scheduling unit 16.

The wireless transmission unit 14 transmits the data received by the wired communication unit 11 to the wireless slave device N300 via the wireless communication link L20 using the wireless communication interface 904. [

The wireless receiving unit 15 receives data transmitted from the wireless slave device N300 via the wireless communication link L20 using the wireless communication interface 904. [

The wireless scheduling unit 16 generates a data transmission schedule to the wireless slave device N300.

More specifically, the wireless scheduling unit 16 generates a real-time data period (first data) for transmission of real-time data (first data) within a communication period (wireless communication period) for wireless communication with the wireless slave device N300 A first data period).

Then, the wireless scheduling unit 16 intensively transmits the real-time data to the wireless slave device N300 in the real-time data period.

When the communication cycle remains at the time when the transmission of the real-time data by the wireless slave device N300 is completed, the wireless scheduler 16 sets the remaining time of the communication cycle as non-real-time data (second data) (Second data period).

Then, the wireless scheduling unit 16 intensively transmits the non-real-time data to the wireless slave device N300 in the non-real-time data period.

Information on the number and arrangement of network devices required for scheduling by the wireless scheduler 16 is acquired manually by setting it at initial setting or by automatically learning and analyzing control frames flowing through the network.

The queue management unit 12 for each priority may be located inside the wireless communication unit 13 because it is used when data is transmitted from the high-speed wired communication link L1 to the low-speed wireless communication link L20.

In the wireless slave device 1 (N301), the wired communication unit 21 receives data to be transmitted from the slave device N100 to the master device N1 via the wired communication link L30 using the wired communication interface 907. [

The wired communication unit 21 transmits the data transmitted from the master device N1 to the slave device N100 via the wired communication link L30 using the wired communication interface 907. [

The priority queue management unit 22 manages the queues provided for each degree of priority.

The priority queue is provided in the storage unit 27, which is a storage area of data.

That is, the storage unit 27 stores real-time data and non-real-time data for each priority degree.

The priority queue management unit 22 stores the received real-time data in a queue having a high priority when real-time data is received, and stores the received non-real-time data in a queue having a high priority if the real- .

In addition, the priority queue management unit 22 reads real-time data from a queue having a high priority and reads non-real-time data from a queue having a low priority.

The wireless communication unit 23 performs wireless communication with the wireless slave device N300.

The wireless communication unit 23 includes a wireless transmission unit 24 and a wireless reception unit 25.

The wireless transmission unit 24 transmits the data received by the wired communication unit 21 to the wireless master device N201 via the wireless communication link L20 using the wireless communication interface 908. [

Further, it transmits notification data for notifying the number of data stored in the storage unit 27 by priority to the radio master apparatus N201.

The wireless receiving unit 25 receives data transmitted from the wireless master device N201 via the wireless communication link L20 using the wireless communication interface 908. [

The queue management unit 22 for each priority may be located inside the wireless communication unit 23 because it is used when transmitting data from the high-speed wired communication link L30 to the low-speed wireless communication link L20.

As shown in Fig. 4, in this embodiment, the communication cycle for transmitting and receiving data between the master device N1 and the slave device N100 is fixed.

In this embodiment, the radio scheduling unit 16 of the radio master apparatus N201 allocates a real-time data period for transmission of real-time data within a communication period.

Then, the wireless scheduling unit 16 instructs the wireless slave device N300 to transmit real-time data in an arbitrary order during the real-time data period, and causes real-time data to be transmitted for each wireless slave device N300.

In a case where the communication cycle remains at the time when the transmission of the real-time data by the plurality of wireless slave devices N300 is completed, the radio scheduling unit 16 sets the remaining time of the communication cycle as a ratio Time data period (second data period).

The wireless scheduling unit 16 instructs the wireless slave device N300 to transmit non-real-time data in an arbitrary order during the non-real-time data period, and causes the wireless slave device N300 to transmit non-real-time data.

The wireless scheduling unit 16 also stops transmission of the non-real-time data when the remaining time of the communication cycle becomes less than the threshold, even if there is a wireless slave device N300 that has not transmitted the non-real-time data.

Since the communication cycle is repeated, the wireless scheduler 16 repeats the operation of allocating the real-time data period and the non-real-time data period at each communication cycle.

Next, details of the operation example in the real-time data period and details of the operation example in the non-real-time data period will be described with reference to Figs. 5 and 6. Fig.

FIG. 5 shows an example of a communication sequence in a real-time data period, and FIG. 6 shows an example of a communication sequence in a non-real-time data period.

As shown in Fig. 5, the real-time data period is started by the coincidence notification to the wireless slave device N300 of the wireless master device N201 (frame notification of the periodic origin from the master device N1).

In each wireless slave device N300, as a response to the all-in-one notification from the wireless master device N201, the wireless transmitting unit 24 transmits notification data for notifying the number of real-time data held in the storage unit 27 and the number of non- To the wireless master device N201.

The radio transmission unit 24 may transmit notification data that notifies only the number of real-time data.

Even if the real time data is not stored in the storage unit 27 in the case where the number of real time data is predetermined in the system setting (for example, the number of real time data to be transmitted in one communication cycle is necessarily one) The radio transmission unit 24 transmits the notification data for notifying the value set by the system setting.

A method for realizing the notification data is described in the second embodiment.

In the radio master apparatus N201, the radio scheduling section 16 performs polling using the radio transmitting section 14 in an arbitrary order.

When a communication error occurs, the radio transmitter 14 executes a retransmission procedure and the radio receiver 15 receives real-time data from each radio slave N300.

At the time when the reception of the real time data from all the wireless slave devices N300 is finished, the wireless scheduling unit 16, from the remaining time of the communication cycle, according to the number of non real time data held by the wireless master device N201 and each wireless slave device N300, Calculate the scheduling.

Next, an example of operation of the non-real-time data period will be described with reference to FIG.

6, the radio transmitter 14 of the radio master apparatus N201 transmits the non-real-time data held by the radio master apparatus N201 to the radio slave apparatus 1301, and the radio receiver 15 receives the Ack data do.

Thereafter, the radio scheduling unit 16 polls each radio slave device N300 in an arbitrary order, and the radio receiving unit 15 receives the non-real-time data from each radio slave device N300.

Immediately before the end of the communication period, the radio scheduling unit 16 stops the new communication when the remaining time becomes less than the threshold value.

The threshold value is set in consideration of the time required for retransmission control when a communication error occurs.

In the example of FIG. 6, since the non-real time data has not arrived from the wireless slave device 2 (N302) but the remaining time has become less than the threshold value, the wireless scheduling unit 16 further polls the wireless slave device (2) Stopping.

In addition, the order of polling for each wireless slave device N300 by the wireless scheduling unit 16 is determined by ensuring fairness between the wireless slave devices N300.

In this example, non-real-time data is transmitted unicast, but non-real-time data may be broadcast-transmitted or multicast-transmitted.

Next, an operation example of the radio master apparatus N201 according to the present embodiment will be described with reference to the flowcharts of Figs. 7 and 8. Fig.

When the communication cycle is started, the radio transmitter 14 transmits real-time data to each radio slave device N300 (S101).

More specifically, the priority-level queue management unit 12 reads real-time data from the storage unit 17 and outputs the read real-time data to the wireless transmission unit 14.

Then, the radio transmission unit 14 transmits real-time data from the radio communication link L20 to each radio slave device N300 via the radio communication interface 904.

Next, the wireless receiving unit 15 receives the Ack data for the real-time data transmitted in S101 from each wireless slave device N300 (S102).

In this Ack data, the number of real-time data and the number of non-real-time data held in each wireless slave device N300 are reported.

For the wireless slave device N300 that can not receive the Ack data, the wireless transmission unit 14 retransmits the real time data.

Next, the radio scheduling unit 16 determines a polling order of real-time data and a polling order of non-real-time data (S103).

The method of determining the polling order by the radio scheduling unit 16 is arbitrary.

For example, the radio scheduling unit 16 may determine the polling order according to a predetermined order among the radio slave devices N300.

The wireless scheduling unit 16 determines a polling order of real-time data according to the number of real-time data notified from the Ack data and determines a polling order of the non-real-time data according to the number of the non-real- .

Next, the radio transmission unit 14 polls the radio slave device N300 according to the polling procedure determined in S103 (S104).

Next, the wireless receiving unit 15 receives real-time data from the wireless slave device N300 that has been polled in S104 (S105).

If real-time data can not be received from the wireless slave device N300, the radio transmitter 14 performs the polling again.

Next, the wireless scheduling unit 16 determines whether or not real-time data has been received from all the wireless slave devices N300 (S106).

When real-time data is received from all the wireless slave devices N300 (YES in S106), the process proceeds to S107.

On the other hand, if there is a wireless slave device N300 that is not receiving real-time data (NO in S106), the processes in and after S104 are repeated.

In S107, the radio transmission unit 14 transmits the non-real-time data to any one of the radio slave devices N300.

More specifically, the priority queue management unit 12 reads non-real-time data from the storage unit 17 and outputs the read non-real-time data to the wireless transmission unit 14.

Then, the wireless transmission unit 14 transmits the non-real-time data from the wireless communication link L20 to the wireless slave device N300 via the wireless communication interface 904. [

Next, the wireless receiving unit 15 receives the Ack data from the wireless slave device N300 of the transmission destination of the non-real-time data (S108).

When the Ack data can not be received, the wireless transmission unit 14 retransmits the non-real-time data.

Next, the radio transmission unit 14 polls the radio slave device N300 according to the polling procedure determined in S103 (S109).

Next, the wireless receiving unit 15 receives the non-real-time data from the wireless slave device N300 polled in S109 (S110).

If the non-real-time data can not be received from the wireless slave device N300, the wireless transmitting unit 14 performs the polling again.

Next, the wireless scheduling unit 16 determines whether the remaining time of the communication cycle is sufficient, that is, whether the remaining time is equal to or greater than the threshold value (S111).

When the remaining time is equal to or larger than the threshold value (YES in S111), the process of S104 is repeated.

On the other hand, if the remaining time is less than the threshold value (NO in S111), the wireless scheduling unit 16 stops transmission of the non-real-time data even in the presence of the wireless slave device N300 that has not transmitted the non- , And waits for the next communication cycle to be started.

In the case where non-real-time data is received from all the wireless slave devices N300, the radio scheduling unit 16 likewise waits for the next communication cycle to be started.

Next, an operation example of the wireless slave device N300 according to the present embodiment will be described with reference to Fig.

In the wireless slave device N300, the wireless receiving unit 25 receives real-time data from the wireless master device N201 (S201).

More specifically, the wireless receiving unit 25 receives real-time data from the wireless master device N201 from the wireless communication link L20 via the wireless communication interface 908 and transmits the received real-time data to the priority queue management unit 22 .

Next, the wireless transmission unit 24 transmits the Ack data (S203).

More specifically, the priority queue management unit 22 counts the number of real-time data and the number of non-real-time data stored in the storage unit 27 (S202) And outputs the notification data for notifying the number to the wireless transmission unit 24. [

The wireless transmission unit 24 generates Ack data including the notification data output from the priority queue management unit 22 and transmits the generated Ack data from the wireless communication link L20 via the wireless communication interface 90 To the master device N201.

Next, when the radio receiving unit 25 receives the polling notification of the real time data from the radio master apparatus N201 (Yes in S204), the radio transmitting unit 24 transmits the real time data to the radio master apparatus N201 (S205) .

More specifically, the radio receiving unit 25 outputs the polling notification from the radio master apparatus N201 to the queue management unit 22 for each degree of priority.

The priority queue management unit 22 acquires the polling notification from the radio master apparatus N201 and reads the real time data from the storage unit 27. [

The queue management unit 22 for each degree of priority outputs the read real time data to the radio transmission unit 24. [

The radio transmission unit 24 transmits real-time data from the radio communication link L20 to the radio master apparatus N201 via the radio communication interface 908. [

When the non-real-time data is transmitted from the wireless master device N201, the wireless receiver 25 receives the non-real-time data from the wireless master device N201 (S206).

In addition, the radio receiving unit 25 may not receive the non-real-time data from the radio master apparatus N201.

6, the wireless slave device 1 (N301) receives the non-real-time data from the wireless master device N201, while the wireless slave device 2 (N302) and the wireless slave device (N303) Real time data is not received.

When the non-real-time data is received from the radio master apparatus N201, the radio transmitting section 24 transmits the Ack data to the radio master apparatus N201.

Next, when the radio receiving unit 25 has received the polling notification of non-real-time data from the radio master apparatus N201 (YES in S207), the radio transmitting unit 24 transmits the non-real-time data to the radio master apparatus N201 S208).

More specifically, the radio receiving unit 25 outputs the polling notification from the radio master apparatus N201 to the queue management unit 22 for each degree of priority.

The priority queue management section 22 acquires the polling notification from the radio master device N201 and reads the non real time data from the storage section 27. [

The queue management unit 22 for each degree of priority outputs the read non real time data to the wireless transmission unit 24. [

The wireless transmission unit 24 transmits non-real-time data from the wireless communication link L20 to the wireless master device N201 via the wireless communication interface 908. [

*** Effect of Embodiment ***

According to this embodiment, by setting the real-time data period before the non-real-time data period, transmission / reception of real-time data can be reliably performed even if a communication error occurs, and when there is a margin in the period, transmission / .

Therefore, high reliability and high communication efficiency can be realized even in wireless communication in which communication errors tend to occur, and frequency resources can be effectively used.

Embodiment 2

In this embodiment, a concrete method of notifying the number of real-time data and the number of non-real-time data held by the wireless slave device N300 to the wireless master device N201 by the wireless slave device N300 will be described.

In the present embodiment, the wireless transmission unit 24 of the wireless slave device N300 is provided with a queue notification processor 26 for each priority.

The priority-level queue notification processing unit 26 performs processing for notifying the number of real-time data and the number of non-real-time data held in the storage unit 27. [

More specifically, the queue notification processor 26 for each priority classifies the number of real-time data and the number of non-real-time data counted by the priority queue manager 22 into Ack data transmitted in S203 of Fig. 9 Quot;

The priority queue notifying processor 26 determines the number of real-time data and the number of non-real-time data held by the wireless slave device N300 based on 802.11 (non-patent document 2), without providing a new communication procedure or frame And notifies the radio master apparatus N201.

Hereinafter, two methods of notifying by priority queue notification processing section 26 are shown.

First, the Duration field in the Ack frame handled by the MAC layer is used (FIG. 11).

The second method uses the SERVICE field in the PPDU frame handled by the PHY layer (Fig. 12).

In the first method, the priority queue notification processor 26 notifies the number of data using the Duration field as shown in FIG.

The 16 bits of the Duration field is a field indicating a future communication time in a normal wireless LAN. For example, by setting the value of the 12th bit to 1, the access point of the wireless LAN transmits 4096? As shown in FIG.

As shown in FIG. 13, the priority queue notification processor 26 uses the 0th to 11th bits (b0 to b11) to notify the number of data in the queue corresponding to the four priorities .

In this embodiment, since two types of data, real-time data and non-real-time data, are provided, the number of real-time data is notified using b9 to b11 as shown in Fig. 13, It is considered to notify the number of data.

In the second method, the priority queue notification processor 26 notifies the number of data using 16 bits of the SERVICE field which is a reserved area.

14, similarly to the first method, the queue notification processor 26 for each degree of priority also uses b0 to b11 to determine whether or not the data in the queue corresponding to the four priorities The number of times that the number of

In this embodiment, since two types of data, real-time data and non-real-time data, are provided, the number of real-time data is notified using b9 to b11 as shown in Fig. 14, It is considered to notify the number of real-time data.

In the example of FIGS. 13 and 14, since 3 bits are used, the number of real-time data and the number of non-real-time data to be reported are in the range of 0 to 7, respectively.

Since the maximum number that can be notified to the wireless master apparatus N201 is seven, when seven or more real-time data or non-real-time data are held in the storage unit 27, the actual number can not be notified. However, The influence on the light is considered to be slight.

The number of data held in the storage unit 27 may be reported using the number of bits of three or more bits.

In Fig. 13 and Fig. 14, correspondence to the four priorities is made so as to correspond to QoS classified into classes.

The 16 bits of the Duration field and the 16 bits of the SERVICE field may be associated with a priority other than four.

In the industrial network, in principle, the use of wireless communication is limited to the factories, and even if the 802.11 frame for wireless LAN is used in the usage form shown in Fig. 13 or 14, .

***bookkeeping***

In the first and second embodiments, examples in which real-time data and non-real-time data correspond to two-stage priorities have been described. However, three or more priorities may be associated.

In this case, the radio scheduling unit 16 keeps a communication cycle at the time when the transmission of the second data, which is data of the second priority by the plurality of radio slave devices N300, is completed, When any one of the wireless slave devices N300 holds the third data having lower priority than the second data, the remaining time of the communication cycle is allocated to the third data period for transmission of the third data.

Then, in the third data period, the wireless scheduling unit 16 causes the wireless slave device N300 holding the third data to transmit the third data.

The wireless scheduling unit 16 also performs the same processing after the fourth data.

In the first and second embodiments, an example has been described in which the wireless master device N201 is connected to one master device N1 and the wireless slave device N300 is connected to the slave device N100 on a one-to-one basis.

Depending on the configuration of the industrial network, the wireless master apparatus N201 may be connected to a plurality of master apparatuses N1 belonging to different industrial networks.

Further, the wireless slave device N300 may be connected to a plurality of industrial slave devices N100 belonging to another industrial network.

In the first and second embodiments, an example in which the present invention is applied to an industrial network has been described. However, if the master device and the slave device transmit and receive data by wireless communication, Can be applied to networks other than industrial networks.

*** Explanation of hardware configuration ***

Finally, the hardware configuration of the wireless master device N201 and wireless slave device N300 is supplemented.

The wireless master device N201 and the wireless slave device N300 are computers.

Processors 901 and 905 shown in Fig. 15 are ICs (Integrated Circuits) that perform processing.

The processors 901 and 905 are a central processing unit (CPU), a digital signal processor (DSP), and the like.

The storage devices 902 and 906 shown in Fig. 15 are a random access memory (RAM), a read only memory (ROM), a flash memory, a hard disk drive (HDD), and the like.

The wired communication interfaces 903 and 907 and the wireless communication interfaces 904 and 908 shown in Fig. 15 include a receiver for receiving data and a transmitter for transmitting data.

The wired communication interfaces 903 and 907 and the wireless communication interfaces 904 and 908 are, for example, a communication chip or a NIC (Network Interface Card).

The storage devices 902 and 906 also store an OS (Operating System).

At least a part of the OS is executed by the processors 901 and 905. [

The processor 901 executes at least a part of the OS and controls the functions of the wired communication unit 11, the priority queue management unit 12, the wireless transmission unit 14, the wireless reception unit 15, A program for realizing the function of the scheduling unit 16 is executed.

The processor 905 executes at least a part of the OS and controls the wired communication unit 21, the priority queue management unit 22, the wireless transmission unit 24, and the wireless reception unit 25, which are functional components of the wireless slave device N300. (And the priority queue notification processor 26).

The program for realizing the functions of the wireless master apparatus N201 and the program for realizing the functions of the wireless slave apparatus N300 may be stored in a storage medium such as a magnetic disk, a flexible disk, an optical disk, a compact disk, a Blu- Or may be stored in a portable storage medium.

Also, the functions of the wireless master device N201 and the functions of the wireless slave device N300 may be replaced by "processing circuit", "circuit", "process", "procedure", or "process".

Processing circuit " or " circuit " includes not only processors 901 and 905, but also other types of processing circuits, such as logic ICs, gate arrays (GA), application specific integrated circuits (ASICs), or field programmable gate arrays Concept.

N1: Master device
N100: Slave device
N101: Slave device (1)
N102: Slave device (2)
N103: Slave device (3)
N104: Slave device (m)
N201: Wireless master device
N300: Wireless slave device
N301: Wireless slave device (1)
N302: Wireless slave device (2)
N303: Wireless slave device (3)
N304: Wireless slave device (m)
11:
12: priority queue manager
13:
14:
15:
16: radio scheduling unit
17:
21:
22: priority queue management unit
23:
24:
25: Wireless receiver
26: Priority queue notification processor
27:

Claims (12)

Allocating a first data period for transmitting the first data within a wireless communication period for performing wireless communication with a wireless communication device that transmits first data and second data having a lower priority than the first data, The wireless communication device causes the first data to be transmitted to the wireless communication device in the first data period and when the wireless communication period remains at the time when the transmission of the first data by the wireless communication device is completed, A second data period for transmitting the second data, and for causing the wireless communication device to transmit the second data during the second data period;
A first receiving unit receiving the first data in the first data period and a second receiving unit receiving the second data in the second data period,
.
The method according to claim 1,
Wherein the wireless scheduler comprises:
A first data period for transmitting the first data is set within a wireless communication period for performing wireless communication with a plurality of wireless communication devices each transmitting first data and second data having lower priority than the first data The first data is transmitted to the plurality of wireless communication devices in the first data period, and when the transmission of the first data by the plurality of wireless communication devices is completed, the wireless communication period remains And allocates the remaining time of the wireless communication period to a second data period for transmission of the second data, and in the second data period, notifies the wireless communication apparatus of at least some of the plurality of wireless communication apparatus To transmit the second data
Wireless communication device.
3. The method of claim 2,
Wherein the wireless scheduler comprises:
The control means instructs the wireless communication device to transmit the first data for each of the wireless communication devices in the arbitrary order during the first data period so as to transmit the first data for each wireless communication device, , Instructs the wireless communication device to transmit the second data, and causes the wireless communication device to transmit the second data
Wireless communication device.
The method of claim 3,
Wherein the wireless scheduler comprises:
When the remaining time of the wireless communication period becomes less than the threshold value, transmission of the second data is stopped even if there is a wireless communication apparatus that has not transmitted the second data
Wireless communication device.
The method according to claim 1,
The wireless communication period is repeated,
Wherein the wireless scheduler allocates the first data period and the second data period for each wireless communication period
Wireless communication device.
3. The method of claim 2,
Wherein the wireless scheduler comprises:
When the transmission of the second data by the plurality of wireless communication devices is completed, the wireless communication period is left, and when any of the plurality of wireless communication devices has a priority lower than that of the second data 3 data is retained, the remaining time of the wireless communication period is assigned to a third data period for transmission of the third data, and in the third data period, To cause the device to transmit the third data
Wireless communication device.
A wireless communication device, which is a computer,
Allocating a first data period for transmitting the first data within a wireless communication period for performing wireless communication with a wireless communication device that transmits first data and second data having a lower priority than the first data, To transmit the first data to the wireless communication device in a first data period, to receive the first data in the first data period,
Allocating a remaining time of the wireless communication period to a second data period for transmitting the second data when the wireless communication period is left at the time when the transmission of the first data by the wireless communication device is completed, To transmit the second data to the wireless communication device in the second data period, and to receive the second data in the second data period
Wireless communication method.
Allocating a first data period for transmitting the first data within a wireless communication period for performing wireless communication with a wireless communication device that transmits first data and second data having a lower priority than the first data, The wireless communication device causes the first data to be transmitted to the wireless communication device in the first data period and when the wireless communication period remains at the time when the transmission of the first data by the wireless communication device is completed, And a second data period for transmitting the second data, and for causing the wireless communication device to transmit the second data during the second data period,
A wireless receiving process of receiving the first data in the first data period and receiving the second data in the second data period,
A wireless communication program stored in a computer-readable recording medium which is executed by a wireless communication apparatus which is a computer. delete delete delete delete

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