JPH11261557A - Radio communications device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make communication between a radio master station and plural radio slave stations with excellent efficiency reliably. SOLUTION: A radio relay center S1 in a network of a radio master station M receives refresh data to radio slave stations S3 to S5 from the station M and, as substitute for the master station, performs refresh of the stations S3 to S5 in a network of a self-station by using the refresh data. During the time, refresh is cyclically continued with the other radio slave stations S2 and S6 to S8 in the network of the station M.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wireless communication apparatus in which a wireless master station cyclically communicates with a plurality of wireless slave stations, and more particularly to a wireless communication apparatus which performs highly reliable communication at high speed. .

[0002]

2. Description of the Related Art For example, at a manufacturing site, with the demand for computerization, a programmable controller, a CNC,
Networking of robot controllers and the like is progressing. Such FA networks require higher data transmission reliability as well as higher speed and higher performance for improving production efficiency.

In the case of wired communication, a communication cable must be re-installed when a line is added or changed at a manufacturing site or a layout is changed, and data transmission with a moving worker or a moving body is performed. Communication cables must be reconnected, and these are frequently added or changed due to rapid technological progress and product diversification, and data transmission between moving workers and mobile bodies is difficult. Because of the heavy use, the cost and effort for that are not negligible. Therefore, wireless communication that can easily and at a lower cost is responded to in case of layout change or mobile communication station moving during work, and introduction of wireless communication in such a field has been attracting attention. It is becoming more popular.

However, in packet radio communication using radio waves, the communication environment is much worse than in wired communication, and noise is mixed, fading occurs due to reflection of radio waves, radio waves are blocked due to passage of obstacles, radio field strength is reduced, and the like. Therefore, an error occurs in the data or a packet is lost in the middle of a communication path, and a communication error occurs on a daily basis.

[0005]

Therefore, in wireless communication, generally, a reception notification is sent back from a radio reception station to a radio transmission station, and the reception notification does not reach the radio transmission station within a predetermined time or does not reach the radio transmission station. If the received reception notification is an error reception notification, a packet in which a communication error has occurred is immediately retransmitted, that is, so-called ARQ (Auto Repeat reQuest).
The method recovers a communication error caused by a high-speed change of the radio wave intensity due to noise or the like and maintains the reliability of the wireless communication. Therefore, in wireless communication, a round-trip data transmission time between data transmission and notification of the reception is required, and transmission efficiency is reduced.

In particular, in the case of a wireless communication device that performs wireless relay as shown in FIG. 7, the data transmission time is further increased and the transmission efficiency is significantly reduced. In FIG.
A wireless master station M and a plurality of wireless slave stations S1, S2, S
3, S4, and S5, cyclically transmits and receives refresh data. The wireless slave stations S1 and S2 belong to the first network ch1 having the wireless master station M as a core, and the wireless slave stations S3, S4 and S5
Belongs to a second network ch2 having a slave station S1 having a function of a radio relay station as a core, and the radio master station M cyclically communicates with the radio slave stations S1 and S2 of the first network ch1. To directly transmit and receive the refresh data,
At the same time, the wireless slave station (wireless relay station) S1 that transmits the refresh data to the wireless slave stations S3, S4, and S5 receives the refresh data, and transmits the refresh data to the wireless slave stations S3, S4, and S5. In S5, the communication is cyclically performed to transmit and receive the refresh data.

FIG. 8 shows a time chart of wireless relay between the wireless master station M and the wireless slave station S3 according to the conventional procedure. In FIG. 8, first, the radio master station M
Generates refresh data (command) for the wireless slave station S3 (t1) and transmits it to the wireless relay station S1 (t2). The wireless relay station S1 relays the refresh data (t3) and transmits the refresh data to the wireless slave station S3 (t2). The wireless slave station S3 processes this command (t4), and transmits a reception notification (response) to the wireless relay station S1 (t2). The wireless relay station S1 relays the response (t3) and transmits the response to the wireless master station M (t2). Therefore, the required communication time during this time is
t1 + t2 × 4 + t3 × 2 + t4, and the communication time for the wireless slave station S3 alone is usually several tens of milliseconds.
c. This necessitates a reduction in data transmission efficiency in the entire communication system.

[0008] The present invention solves the above-mentioned problems and provides an ARQ
An object of the present invention is to provide a wireless communication device capable of performing highly reliable wireless communication employing a system with high transmission efficiency.

[0009]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention is directed to a wireless communication apparatus for cyclically transmitting and receiving refresh data between a wireless master station and a plurality of wireless slave stations. A wireless master station as a core, a first network to which a first wireless slave station group including a wireless relay station belongs, and the wireless relay station as a core,
A second network to which a second wireless slave station group belongs, wherein the wireless relay station receives refresh data for a wireless slave station belonging to the second wireless slave station group from a wireless master station, It is characterized in that proxy refresh is cyclically performed on the wireless slave stations belonging to the second wireless slave station group using the data.

[0010] In a second aspect of the present invention, in the first aspect, a channel used for communication in the first network is different from a channel used for communication in the second network. The channel is switched when the station performs the proxy refresh.

[0011] A channel means a use frame of a frequency, a spread spectrum method, a data modulation method, or the like used for wireless communication, and is assigned to prevent interference with other networks.

According to a third aspect of the present invention, in the second aspect of the present invention, a frequency of a channel used for communication in the first network is different from a frequency of a channel used for communication in the second network. It is characterized by being.

According to a fourth aspect of the present invention, in the second aspect of the present invention, the spreading code / hopping sequence of the channel used for communication in the first network is used for spreading the channel used for communication in the second network. It is characterized by being different from a code / hopping sequence.

According to a fifth aspect of the present invention, in the second aspect of the invention, when the wireless master station cyclically transmits / receives to / from the first wireless slave station group in the first network, the wireless relay station transmits the wireless relay station to another wireless slave station. It is characterized in that polling is performed at the beginning of a communication cycle with priority over a slave station.

According to a sixth aspect of the present invention, in the fifth aspect of the present invention, the wireless relay station includes a plurality of wireless relay stations, and the polling order of the wireless master station between the plurality of wireless relay stations is determined by the number of relay slave wireless stations. Is characterized by being given priority over the one with the highest number.

According to a seventh aspect of the present invention, in the fifth aspect of the present invention, there are a plurality of the wireless relay stations, and at least one network is linked in a chain form at least one of the second networks. Then, a multistage network is configured, the relay stations of the multistage network sequentially perform proxy refresh, and the polling order of the radio master station between the plurality of radio relay stations is determined by the radio relay station. It is characterized in that priority is given to one having a large number of stages.

According to an eighth aspect of the present invention, in the first aspect, the wireless master station interrupts communication and waits while the wireless relay station performs proxy refresh.

According to a ninth aspect of the present invention, in the first aspect of the present invention, when the wireless relay station performs a proxy refresh, a management timer is started and the proxy refresh is performed only within the time-up time of the management timer. It is characterized by the following.

A tenth aspect of the present invention is characterized in that, in the first aspect of the present invention, the wireless relay station has a wireless slave station function.

According to an eleventh aspect of the present invention, in the first aspect of the present invention, the wireless master station and the wireless slave station are installed in a manufacturing factory, and the antenna of the wireless relay station has a height that can see through the wireless master station and the wireless slave station. It is characterized by being installed in a place.

[0021]

Embodiments of the present invention will be described below.
This will be described with reference to the drawings.

FIG. 1 shows an embodiment of the present invention.
FIG. 1 is an explanatory diagram illustrating an outline of a wireless communication network including a wireless relay station in a programmable controller system. In FIG. 1, a wireless master station M is connected to a remote I / O master 1 of a programmable controller via a remote I / O network 2. The first wireless slave station group (wireless slave stations S1, S2, S6, S7, S8) including the wireless relay stations (wireless slave stations) S1 and S8 with the wireless master station M as the core belongs to the first group. The network ch1 and the wireless relay station S
1 as a core and a second network ch to which a second group of wireless slave stations (wireless slave stations S3, S4, S5) belong
2 and a third network ch3 to which a third wireless slave station group (wireless slave stations S9 and S10) belongs, with the wireless relay station S8 as a core.

The wireless master station M includes a first wireless slave station group (wireless slave stations S1, S8, S2, S6, S
7) to transmit and receive the refresh data cyclically, and to the radio relay stations S1 and S8 also serving as radio relay stations, the radio slave stations S3, S4, S4 belonging to the respective networks ch2, ch3.
5 or the wireless slave stations S9 and S10 are transmitted / received by including the OUT refresh data in the communication data.
The wireless relay stations S1 and S8, which also serve as wireless relay stations, take out these OUT refresh data received from the wireless master station M and use them to send them to the wireless slave stations belonging to the second or third wireless slave station group. On the other hand, a proxy refresh is performed cyclically.

When the radio relay stations S1 and S8 communicate on the respective networks ch2 and ch3, they switch to a channel having a frequency different from that of the network ch1 of the radio master station M. Also, the communication frequencies used in the network ch2 of the wireless relay station S1 and the network ch3 of the wireless relay station S8 are different from each other, so that the wireless communication of each network does not interfere with each other.

The wireless master station M is connected to the first network ch
1, when transmitting and receiving cyclically to the first wireless slave station group, the communication is normally performed in the order of the number of the wireless slave stations, but the wireless relay stations S1 and S8 are prioritized over the other wireless slave stations. Poll at the beginning of the communication cycle.

The relay processing in FIG. 1 will be described more specifically with reference to FIGS.

FIG. 2 is a timing chart showing the exchange of communications between the wireless communication stations in a communication cycle.
In FIG. 2, in the network ch1 of the wireless master station M, at the beginning of a communication cycle, the wireless master station M communicates with the wireless relay station S1, then another wireless relay station S8, and then the wireless slave station. The communication is sequentially performed with S2, S6, and S7, and the communication cycle ends.

The radio master station M issues a command to the radio relay station S1 to the radio relay station S1 as a radio slave station, and a command to the radio relay station S1 to the radio slave stations S3, S4, and S5 in the network ch2 of the radio relay station S1. Are generated as a command <1> and transmitted to the radio relay station S1. Upon receiving this command <1>, the wireless relay station S1 performs the communication processing shown in FIG.
First, in step 301 in FIG. 3, refresh processing is performed with the wireless master station M as in the network ch1 (command <1> and response <1>) in FIG. 2, and if this communication is successful, Next, in step 302, proxy refresh processing is performed on the wireless slave stations S3, S4, and S5 in the network ch2 as in the network ch2 in FIG.

FIG. 4 shows a detailed flow of the above-mentioned step 301, the refresh processing with the radio master station M. FIG.
In step S401, the wireless relay station S1 receives a command from the wireless master station M in step 401. Next Step 40
In step 2, the WNID of the wireless slave station in the network ch2, which is the object of the refresh processing, is extracted from the received command, and it is checked which wireless slave station is to be refreshed. Command <1>, command <3>, command <4 for target wireless slave stations S1, S3, S4, S5
>, Command <5>, and extract its own command <1>.
Performs the reception processing by itself, and the other commands are commands <3>, <4>, and <5 for the respective wireless slave stations S3, S4, and S5 for proxy refresh.
Assemble the packet of>. Next, at step 404,
Notification of the reception result and the IN refresh data of the wireless slave station and the own station in the network ch2 collected in the immediately preceding communication cycle described later (response <1
>) To assemble the packet. Last step 405
Then, as shown in FIG.

FIG. 5 shows a detailed flow of step 302 in FIG. In FIG. 5, the radio relay station S1 first uses the channel ch used for communication with the radio master station M in step 501.
The frequency is switched from frequency 1 to frequency of channel ch2.
As a result, even if the wireless master station M is communicating with another wireless slave station, the wireless relay station S1 can communicate with the network ch.
2 can be communicated.

Next, in step 502, prior to the proxy refresh, a management timer is started to manage the processing time. The time-up time of the management timer is set based on the number of wireless slave stations to be refreshed obtained in step 402 of FIG.

In the next step 503, a command <3> is transmitted to the wireless slave station S3.
At 4, it is checked whether or not all the target wireless slave stations of the network ch2 have been refreshed. In this case, since the wireless slave stations S4 and S5 still remain (no), the process proceeds to step 505, and the management timer times out. Check if you have done it. Normally, since the management timer has not expired (yes), the process proceeds to step 506, moves the pointer to the next wireless slave station S4, and returns to step 503. In step 503, the process is completed up to the refresh of the wireless slave station S5, and when the proxy refresh of the wireless relay station S1 shown in the network ch2 in FIG. , Channel used
The processing returns to 1 and the proxy refresh processing ends.

When the proxy refresh of the wireless relay station S1 is completed, another wireless relay station S8 receives the command <8> from the wireless master station M, and like the wireless relay station S1, the wireless slave station S9, For S10, proxy refresh processing is performed as in the network ch3 in FIG. Since the communication frequency used for the network ch3 is different from the communication frequency of the network ch2, as shown in FIG. 2, the commands <8> to <6> of the network ch1 and the commands <3> of the network ch2. ~ Response <5> and Network c
The command <9> to the response <10> of h3 can be simultaneously wirelessly communicated in parallel.

In the communication cycle of the wireless master station M,
As described above, the radio relay stations S1 and S8 are polled prior to the other radio slave stations S2, S6 and S7, and the refresh processing is advanced, so that the parallel processing of refreshing with another network is more effective. In the case where there are a plurality of wireless relay stations such as S1 and S8, as is clear from FIG. Since the density of the parallel processing increases, a more preferable state is obtained.

Since the IN refresh data is collected during the response from the wireless slave stations in the respective networks by the proxy refresh of the wireless relay stations S1 and S8, the response to the wireless master station M in the next communication cycle is performed. These IN refresh data are incorporated in <1> and <8>.

In the embodiment of the present invention described above, the radio master station M-the radio relay station S1, the radio master station M
-Although the case of one-stage wireless relay with the wireless relay station S8 has been described, the wireless relay station is further replaced by the wireless master station M-wireless relay station S1-wireless relay station Sn # before the wireless relay station S1. In this way, a multistage network is formed by linking in a chain, and proxy refresh is performed by successively relaying, so that the present invention can be applied to collective management of a wider factory with poor visibility. In such a case, if the order of polling in the communication cycle of the wireless master station M is prioritized to a wireless relay station having a large number of relay stages among a plurality of wireless relay stations in one network, parallel processing of refresh is often performed. It is possible to suppress an increase in the communication cycle time of the wireless master station M. Note that, in the case of multi-stage wireless relay, the middle-stage wireless relay station is the wireless master station M with respect to the next-stage wireless relay station.
Function.

Also, in the above embodiment, channels of different frequencies are assigned to each network, and the radio relay station performs communication for each channel by switching this frequency. In the case of using the wireless communication device of the above, it is preferable to perform communication for each channel by switching a spreading code / hopping sequence using a spread spectrum method. If channel switching is performed by switching between a spreading code and a hopping sequence, it is possible to prevent both inter-channel interference and mixing of noise and the like while a plurality of networks use a common frequency.

Further, when the amount of communication data is relatively small and the ratio of processing time for relay operation or the like is large, or when communication errors occur frequently and the retransmission processing time is long, for example, the channel The channels of multiple networks are shared, such as using a common frequency, so that concurrent processing of these networks is not performed, and the wireless master station interrupts communication while the wireless relay station performs proxy refresh. Alternatively, the user may wait.

In this case, the processing order in FIG. 2 is slightly changed.
The command <8> of the network ch1 is executed after the response <5> of the network ch2 ends, and the command <2> of the network ch1 is executed after the response <10> of the network ch3 ends. . By doing so, the communication cycle becomes longer, but the equipment cost is reduced, and more radio systems can be introduced with higher density.

By the way, the wireless master station M has the remote I
Cable connection with / O master station and monitor is required,
Since each of the wireless slave stations S is connected to a machine or the like in the manufacturing site via a cable, both the wireless master station M and the wireless slave station S are installed near the floor. For this reason, mutual prospects are not always good, and the environment is such that radio waves are difficult to reach. In such a case, as shown in FIG. 6, a dedicated wireless relay station C is used to install the wireless relay station C at a position with good visibility near the ceiling of the factory, or the wireless relay station C If the antenna is placed near the floor and its antenna is installed at a high place on a wall with good visibility, errors in wireless communication are reduced, and data transmission efficiency is further improved. As described above, in the wireless communication device of the present invention, one network may include only a single wireless relay station.

[0041]

As will be understood from the above description, according to the first aspect of the present invention, the radio relay station receives the refresh data for the radio slave stations belonging to the second radio slave station group from the radio master station. Then, by using this refresh data, the proxy refresh is cyclically performed on the wireless slave stations belonging to the second wireless slave station group. And the communication cycle can be shortened, thereby improving the overall data transmission efficiency. Moreover, since the ARQ method can be used, high reliability of communication can be maintained.

According to the second, third or fourth aspect of the present invention, in the first aspect, a channel used for communication in the first network and a channel used for communication in the second network are provided. When the wireless relay station performs proxy refresh, the channels are switched by making the frequency, spreading code, hopping sequence, and the like different, so that wireless communication can be performed simultaneously without mutual interference, and a plurality of wireless slaves can be used. The stations can be refreshed at the same time and the transmission efficiency is improved.

According to the fifth aspect of the present invention, in the second aspect, when the wireless master station cyclically transmits / receives to / from the first wireless slave station group in the first network, the wireless relay station transmits the wireless relay station to another wireless slave station. Since polling is performed at the beginning of the communication cycle prior to the slave station, the proxy refresh of the wireless relay station is completed by the end of the communication cycle of the wireless master station. Is improved.

According to the invention of claim 6 or 7,
The parallel processing density of the refresh processing of the wireless master station and the refresh processing of the relay destination according to claim 5 can be further increased, and there is an effect of shortening the communication cycle time.

According to the eighth aspect of the present invention, in the first aspect of the present invention, the wireless master station interrupts the communication and waits while the wireless relay station performs the proxy refresh. The channel used for communication in the network and the channel used for communication in the second network are made the same, the frequency and the like are made common, the equipment cost is reduced, and more wireless systems can be introduced. Become.

According to the ninth aspect of the present invention, in the first aspect of the present invention, when the radio relay station performs a proxy refresh, a management timer is started, and the proxy refresh is performed only within the time-up time of the management timer. Therefore, even when the proxy refresh of the wireless relay station is delayed, communication between the wireless master station and the wireless relay station can be performed at the time of the next polling from the wireless master station to the wireless relay station. .

According to the tenth aspect of the present invention, since the radio relay station has a radio slave station function, a radio relay station can be selected from the radio slave stations without installing an independent radio relay station. Then, the present invention can be implemented.

According to the eleventh aspect of the present invention, the radio master station and the radio slave station are installed in the manufacturing factory, and the antenna of the radio relay station is installed at a high place where the radio master station and the radio slave station can be seen. Communication disturbance in the passage of the relay radio wave is reduced, and a wide range network can be secured.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram illustrating an overview of a wireless communication network according to an embodiment of the present invention;

FIG. 2 is an explanatory diagram illustrating a wireless relay process according to the embodiment of the present invention;

FIG. 3 is a flowchart showing a proxy refresh communication processing flow of the wireless relay station in FIG. 2;

FIG. 4 is a flowchart showing a refresh processing flow between the master and the wireless relay station in FIG. 3;

FIG. 5 is a flowchart showing a proxy refresh processing flow of the wireless relay station in FIG. 3;

FIG. 6 is an explanatory diagram showing an example of the arrangement of wireless relay stations according to the present invention.

FIG. 7 is a block diagram showing a conventional wireless communication device.

FIG. 8 is an explanatory diagram illustrating a relay process of a conventional wireless communication device.

[Explanation of symbols]

M wireless master station S2, S3, S4, S5, S6, S7, S9, S10
Wireless slave station S1, S8, C Wireless relay station ch1, ch2, ch3 Network

Claims (11)

[Claims] 1. A wireless communication apparatus for cyclically transmitting and receiving refresh data between a wireless master station and a plurality of wireless slave stations, wherein a first wireless slave station group including a wireless master station as a core and including a wireless relay station A first network to which the wireless relay station belongs, and a second network to which a second wireless slave station group belongs, wherein the wireless relay station is a second wireless slave station from a wireless master station. Wireless communication receiving refresh data for a wireless slave station belonging to a group, and cyclically performing a proxy refresh for a wireless slave station belonging to a second wireless slave station group using the refresh data; apparatus. 2. The method according to claim 1, wherein a channel used for communication in the first network is different from a channel used for communication in the second network, and the channel is switched when the radio relay station performs proxy refresh. The wireless communication device according to claim 1, wherein: 3. The wireless communication system according to claim 2, wherein a frequency of a channel used for communication in the first network is different from a frequency of a channel used for communication in the second network. Communication device. 4. A spread code / hopping sequence of a channel used for communication in the first network is different from a spread code / hopping sequence of a channel used for communication in the second network. Claim 2
The wireless communication device according to claim 1. 5. When a wireless master station cyclically transmits / receives to / from a first wireless slave station group in a first network, the wireless relay station is given priority over other wireless slave stations at the beginning of a communication cycle. The wireless communication device according to claim 2, wherein polling is performed. 6. The wireless relay station according to claim 1, wherein a plurality of the wireless relay stations are provided, and a polling order of the wireless master station between the plurality of wireless relay stations is given priority to a relay station having a larger number of relay slave stations. The wireless communication device according to claim 5, wherein 7. The radio relay station according to claim 2, wherein said radio relay station includes a plurality of radio relay stations.
One or more networks are linked in a chain form at least beyond one of the above networks to form a multi-stage network, and the relay stations of the multi-stage network sequentially perform proxy refresh. 6. The wireless communication apparatus according to claim 5, wherein the polling order of the wireless master station between the plurality of wireless relay stations is prioritized in the order of the number of wireless relay stations. 8. The wireless communication apparatus according to claim 1, wherein the wireless master station suspends communication and waits while the wireless relay station performs proxy refresh. 9. The wireless communication according to claim 1, wherein when the wireless relay station performs the proxy refresh, a management timer is started and the proxy refresh is performed only within a time-up time of the management timer. apparatus. 10. The wireless communication apparatus according to claim 1, wherein said wireless relay station has a wireless slave station function. 11. The wireless master station and the wireless slave station are installed in a manufacturing factory, and the antenna of the wireless relay station is
The wireless communication device according to claim 1, wherein the wireless communication device is installed at a high place where the wireless master station and the wireless slave station can be seen.