JPH06311096A - Radio data transmission device - Google Patents

Abstract

PURPOSE:To improve reliability by always securing the high quality communication between a master station and a slave station. CONSTITUTION:When a transmission request generates in a slave station, a channel is switched to a channel CH 1 and the communication with a master station is started. When the communication with a master station is impossible, the channel is switched to a channel CH 2, a repeating request is transmitted to the surrounding slave station, the station is made to become a repeating station, and a radio communication is performed by using the repeating station and the channel CH 2. When the communication is terminated, the repeating station (slave station) switches the channel to the channel CH 1 and performs the communication with the master station. When the communication with the master station is terminated, the repeating station switches the channel to the channel CH 2 and performs a radio communication with a slave station.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wireless data transmission apparatus applied to, for example, a wireless order management system used in restaurants and the like, a wireless inventory management system used in warehouses and the like.

[0002]

2. Description of the Related Art As a wireless order management system, for example, the one disclosed in Japanese Patent Laid-Open No. 64-88871 is known. As shown in FIG. 7, the stations (ST) 21 and 22 equipped with radios on the transmission line 1, kitchen printers (KP) 31 and 32, and electronic cash registers (TM) 41, 42, 43, and 44 are provided. A handy terminal (HT) 51, which is connected to each of the stations 21 and 22 and is equipped with a plurality of radios,
5n, 61, 62, ... 6n are provided.

Floor printers 21a and 22a are connected to the stations 21 and 22 respectively. Kitchen printers 31 and 32 are installed in different kitchens.

This is because when an order from a customer is entered by operating a key on a handy terminal, order data is wirelessly transmitted to a station, the station manages the order data, and the order data is transmitted to a kitchen printer in the kitchen for printing. It is supposed to be output.

In this system, the station functions as a master station and each handy terminal functions as a slave station. Each slave station uses a common channel to perform wireless communication with the master station. Has become. It should be noted that a plurality of usable channels (about 10 channels) are prepared as wireless devices to be used.

Since each slave station shares one channel, the carrier sense signal is checked before transmission to confirm that no other slave station is using the channel, and then data transmission is started. ing. In this method, if another slave station is using the channel, it waits until the communication ends, but this system causes no problem because the communication data amount is relatively small.

[0007]

In such a system, a high-quality communication line is not always secured at every point in the service area because of wireless communication. In other words, the visibility in the service area is good,
If there are no obstacles, you can secure high quality communication lines at all points in the service area, but in reality various things are arranged in the service area,
In addition, there are places in the service area where communication is poor or where communication is not possible, such as the structure of the building is disadvantageous for wireless communication, or the state of the propagation space changes due to an increase or decrease in the number of customers. there is a possibility.

Handy terminals 51 to 5n and 61
Since ~ 6n is driven by a battery, if the power supply voltage drops, the transmission output drops and the communication distance becomes short.

As described above, in the case where a plurality of mobile stations are provided in the service area so as to be movable relative to the master station and data is wirelessly communicated, the communication quality is deteriorated due to the position of the slave station and the distance from the master station. There was a problem that it was not possible to secure high reliability.

Therefore, the present invention is intended to provide a wireless data transmission apparatus capable of always ensuring high-quality communication between a master station and a slave station and improving reliability.

[0011]

The invention according to claim 1 is
In a wireless data transmission device provided with a master station fixedly arranged in an effective communication area and a plurality of movable slave stations, each slave station wirelessly communicates with the master station on a predetermined specific channel and at the same time as a relay station. Communication means for wirelessly communicating with the slave station on a channel different from the specified channel, means for transmitting a relay request to another slave station when wireless communication with the master station is impossible, and the master station If there is a relay request from another slave station when wireless communication is not being performed, wireless communication will be performed using a channel different from the slave station that made the relay request and a specific channel, and based on the content received from that slave station. Wireless communication with the master station using a specific channel, and wireless communication with the slave station for which a relay request has been made using another channel based on the content received from the master station. Is.

[0012]

In the invention of such a structure, when a child station tries to make wireless communication with the parent station and it is determined that wireless communication with the parent station is impossible due to an obstacle or the like, the child station Send a relay request to the surrounding slave stations. As a result, if the surrounding slave station is not performing wireless communication with the master station, the slave station receives a relay request and wirelessly communicates with the slave station using a channel different from the specific channel for communicating with the master station. Go and receive the data to be sent to the master station. Then, instead of a certain child station, wireless communication is performed with the parent station using a specific channel, and when the communication is completed, the result is transmitted to another child station by another channel.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. In this example, the present invention is applied to an order management system in a restaurant.

FIG. 1 is a diagram showing the configuration of the entire system.
DLC (High Level Data Link Control)
Host computer 12 that centrally manages data in loop 11, POS installed at the payment settlement place with the customer
(Point of Sales) Cash Register 1
3. For example, the printer 14 and the master station 15 installed in the kitchen
Are connected.

In the service area SA, which is managed by the master station 15 wirelessly, n slave stations 161, 162, ... 16n are provided.

Each of the slave stations 161 to 16n is a battery-powered handy terminal, equipped with a keyboard and a display, always brought by a customer service representative, and when the customer takes an order at a table, the order is input as data. It is supposed to do. A wireless device is built in each of the slave stations 161 to 16n, and wireless communication is performed with the master station 15 using a specific channel.

That is, this system uses each slave station 161-1.
When order data is entered in 6n, the slave station to the master station 15
The order data is wirelessly transmitted to the host station 15, and the master station 15 notifies the received order data to the host computer 12, the cash register 13, and the printer 14 via the HDLC loop 11. The host computer 12 manages sales of the entire store, the cash register 13 manages sales data for each customer for settlement with the customer, and the printer 14 prints out to notify the kitchen of the customer's order.

The wireless communication between the master station 15 and each of the slave stations 161 to 16n is carried out as shown in FIG. 2 in a normal case where communication is performed without relay.

That is, the slave stations 161 to 16n are normally in a standby state on a specific channel used for communication with the master station 15, that is, a channel CH2 different from the channel CH1. Switch to channel CH1 and check the idle state of the line by carrier sense. If the channel CH1 is vacant, the line is connected and the channel CH1 is used to perform wireless communication with the master station 15. (Communication means) When the communication is completed, the channel is switched again to the channel CH2 and the standby state is set.

When a relay request is received in the standby state, relay processing is performed.

When communication is carried out via a relay, the communication is carried out as shown in FIG.

That is, when a certain slave station is in the standby state on the channel CH2, a transmission request is generated and it tries to communicate with the master station 15 by switching to the channel CH1. If it is determined that the communication cannot be performed, the channel is returned to the channel CH2 and the idle state of the line is checked by carrier sense. If the surrounding slave station is in the standby state on the channel CH2, the relay request is transmitted to the slave station and then the line is connected. (Relay Request Transmission Means) When a relay station receives a relay request, it checks the availability of the line by carrier sense and then connects the line.

The slave station thus configured and the slave station serving as a relay station perform wireless communication using the channel CH2. (Communication means) When the communication is completed, the slave station, which serves as a relay station, switches the channel to the channel CH1 and checks the vacant state of the channel CH1 by carrier sensing. Communicate with. That is, the data received from a certain slave station is transmitted to the master station 1
Send to 5. When the communication with the master station 15 is completed,
The slave station, which is a relay station, switches the channel to channel CH2 and carries out carrier sensing on channel C with a certain slave station.
The empty state of H2 is checked, and if it is empty, wireless communication is performed using the channel CH2 with the slave station to which the line is connected. That is, the data received from the master station 15 is transmitted to a certain slave station. (Relay Station Means) When this communication is completed, a certain slave station and a slave station that has become a relay station are in the standby state again.

When the master station 15 completes the communication with the slave station, which is a relay station, it returns to the standby state.

In this wireless communication, it is necessary for a certain slave station to distinguish whether the received data is from the master station 15 or from the relay station. The data format is as shown in FIG. , Frame synchronization signal, call signal, transmission request source ID number, relay station ID number and data, the transmission request source ID number and relay station I
If the D number is confirmed, a certain slave station can judge that it is a response from the master station 15. Conversely, the master station 15 can also determine whether the data is direct data from the slave station or data from the relay station.

When a slave station serving as a relay station inputs a key from its own keyboard during relay, as shown in FIG. 5, input data is temporarily stored in a buffer, and a transmission request is issued at the time when relay is completed. Will occur.

In the embodiment having such a structure, as shown in FIG.
When the slave station 16A tries to communicate directly with the master station 15 on the channel CH1 as shown in Fig. 3, when it is determined that it is difficult to communicate directly with the master station, the channel is switched to the channel CH2 and the channel CH2 is changed. Then, the relay request is transmitted to the surrounding slave stations 16B1, 16B2, 16B3 in the standby state.

Upon receiving the relay request, each of the slave stations 16B1 to 16B3 communicates with the slave station 16A on the channel CH2,
The slave station 16A receives the data to be transmitted to the master station 15. When the communication is completed, each of the slave stations 16B1 to 16B3 switches the channel to the channel CH1 and outputs a communication request to the master station 15.

At this time, only the slave station which first outputs the communication request to the master station 15 can communicate with the master station. For example, the slave station 16B1 becomes communicable with the master station and starts communication with the master station 15.

The data thus received from the slave station 16A is transmitted to the master station 15. When the slave station 16A receives the reply from the master station 15, it switches the channel to the channel CH2, communicates with the slave station 16A, and transmits the reply from the master station 15.

As described above, when the slave station 16A cannot directly communicate with the master station 15 due to various reasons such as obstacles, the surrounding slave stations can be used as relay stations to communicate with the master station 15, so that the master station 15 can always communicate with the master station 15. High quality communication can be secured and reliability can be improved.

When there is a relay request from the slave station 16A, the slave stations 16B1 to 16B3 in the standby state are in standby.
All receive data from the slave station 16A and make a transmission request to the master station 15, so even if there is a slave station among the slave stations 16B1 to 16B3 that has difficulty communicating with the master station, a slave station that can communicate Since the station is selected and becomes the relay station, the slave station 16A can reliably communicate with the master station 15 via the relay station.

Further, for example, when data is input from the keyboard during the relay in the slave station 16B1, the data is temporarily stored in the buffer, and after the relay is completed, the channel is switched from the channel CH2 to the channel CH1 and transmitted to the master station 15.

As described above, even when functioning as a relay station, the function as an original slave station can be achieved, so that it is easy to use and the practicality can be improved.

[0035]

As described above, according to the present invention, when it is difficult for a slave station to directly communicate with the master station, another slave station can be used as a relay station to communicate with the master station. Can ensure high-quality communication with the slave station and improve reliability.

[Brief description of drawings]

FIG. 1 is a block diagram of an order management system showing an embodiment of the present invention.

FIG. 2 is a flowchart showing communication control between a master station and a slave station when there is no relay station in the embodiment.

FIG. 3 is a flowchart showing communication control between a master station and a slave station when using a relay station in the embodiment.

FIG. 4 is a diagram showing a communication data format between a master station and a slave station in the embodiment.

FIG. 5 is a flowchart showing a key input process of a slave station in the embodiment.

FIG. 6 is a view for explaining the operation of the same embodiment.

FIG. 7 is a block diagram showing an example of a conventional order management system.

[Explanation of symbols]

 15 ... Parent station 161 to 16n ... Child station

Claims (1)

[Claims] 1. A wireless data transmission apparatus comprising a master station fixedly arranged in an effective communication area and a plurality of freely movable slave stations, wherein each slave station is a specific channel predetermined with the master station. Wireless communication with a slave station that has become a relay station and wireless communication on a channel different from a specific channel, and when a wireless communication with the master station is not possible, a relay request is sent to another slave station. And a wireless communication using a channel different from a specific channel with the slave station having the relay request if there is a relay request from another slave station while not performing wireless communication with the master station. And a slave station wirelessly communicating with the master station using a specific channel based on the received content from the slave station and having a relay request using another channel based on the received content from the master station A relay station that wirelessly communicates with A wireless data transmission device having a step.