JP2935242B2 - Wireless communication system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Summary] A wireless communication system having one or more controllers for transmitting and receiving data to and from a plurality of terminals by wireless communication. In order to solve the problem of acquiring the channel, the controller and / or the terminal that receives the data and sends the response returns until the controller returns the response. And other terminals are configured to acquire other channels.

[Industrial applications]

The present invention relates to a wireless communication system having one or a plurality of controllers for transmitting and receiving data to and from a plurality of terminals by wireless communication.

For example, a single control
When a communication start request is transmitted to the controller via the control channel, the controller divides the frequency into a plurality of data channels and a plurality of data channels. The presence / absence of a signal is checked (check whether the data channel is not a vacant data channel). If there is a vacant data channel, the address of the data channel is transmitted to the terminal so that communication is performed using the data channel. Control·
Make notification using a channel. Based on the result of such a channel acquisition sequence, data transmission / reception is subsequently performed using the data channel. As can be seen, there is a wireless communication system in which a plurality of terminals can simultaneously communicate with a controller using a plurality of respective data channels at the same time. Acquisition of unwanted channels may occur in the sequence.

[Conventional technology]

FIG. 6 is an explanatory diagram of the conventional case, FIG. 7 is a processing flowchart of the conventional case, and FIG. 8 is a time chart of the conventional case. Reference numeral 1 in the figure is a controller, 2A, 2B
Represents a terminal, 3 represents a channel acquisition sequence, 4 represents data transmission, 5 represents a response reply, and a hatched portion represents a carrier existence period.

In FIGS. 6 to 8, a plurality of terminals, for example, terminal A and terminal B are linked under a single controller A so that each terminal can communicate with the controller. Is shown as

In the controller 1, as shown in the flowchart of FIG.
When a command is received via a channel, a vacant data channel is searched for, and the address of the vacant data channel is determined using the control channel.
Notice. Then, it receives data sent from the terminal 2i using the data channel, processes the data, and returns a response using the same data channel.

The time chart during this time is shown in FIG. The period between the terminal and the controller is divided into the following periods: (i) control channel occupation, (ii) data channel n occupation, (iii) data channel n release, and (iv) response return on data channel n. Then, a start request command is transmitted and received at a random time between each terminal and the controller.

In the “data channel n open” period shown in FIG. 8, no radio wave corresponding to the data channel n exists. Therefore, as shown in FIG. 6, another terminal acquires the channel n during the period, and
As shown by the crosses in the figure, a communication error may occur when a response is returned.

[Problems to be solved by the invention]

In the conventional case, a communication error may occur, as described with reference to FIG.

The present invention has been made to solve this problem, and has as its object to solve the problem that another terminal acquires the same channel until a response is returned.

[Means for solving the problem]

FIG. 1 shows a principle configuration diagram of the present invention. In the figure, 1 is a controller, 2A and 2B are terminals, 3 is a channel acquisition sequence, 4 is data transmission, 5 is a response reply, 6 is a carrier transmission provided in the present invention, and a hatched portion represents a carrier existence period. I have.

In the case of the present invention, the data receiving side, for example, the controller 1 in the case shown in the drawing, keeps transmitting the carrier until a response is issued, and the other terminals acquire other channels. Like that.

[Action]

In the case shown in FIG. 1, terminal 2A acquires channel #n through channel acquisition sequence 3 and transmits data. Assuming that the controller 1 receives data on the channel #n, the controller 1 continues to transmit a carrier responding to the same channel #n, and puts a response reply on the carrier when it becomes possible to transmit a response reply. .

Therefore, the other terminal 2B transmits the channel acquisition sequence 3
Is performed, the above channel #n is not in an idle state, so that the channel #n is not obtained. That is, another channel #m is obtained.
Therefore, the problem described with reference to FIG. 6 does not occur.

〔Example〕

FIG. 2 shows the configuration of the controller. In the figure, reference numeral 1 is a controller, 11 is a host device, 12 is a wireless device, 13 is a data processing unit, 14 is a communication control unit, 15 is a wireless control unit, 16 is a channel selection unit, 17 is a wireless input / output unit, 18 Represents an antenna. It is assumed that a plurality of terminals 2 that can communicate with the antenna 18 shown in FIG. 2 exist independently of the controller.

In the case of the present invention, in the illustrated wireless input / output unit 17,
Until the response is returned, the carrier is continuously transmitted.

FIG. 3 shows a processing flowchart in the case of the present invention,
This corresponds to FIG. 7 in the conventional case.

As is clear from comparison with FIG. 7, in the case of the present invention, the carrier is transmitted after the processing is performed (5-1).
At the same time, after performing the processing, the carrier transmission is stopped (6-1). Others are basically the same as the conventional case shown in FIG.

FIG. 4 shows a time chart in the case of the present invention, and corresponds to FIG. 8 in the conventional case.

As is clear from comparison with FIG. 8, in the case of the present invention, "carrier transmission" is provided between "data" shown and "response" shown. For this reason, the state of “data channel n occupancy” following “control channel occupancy” is maintained between the terminal and the controller.

FIG. 5 is a time chart for explaining another embodiment of the present invention. Symbols a, b, c, d, and e in the figure correspond to the "start request command", "notify idle channel n", "data", "carrier transmission", and "response" shown in FIG. 4, respectively. I have.

As shown in FIG. 5, when there is a period in which the transmission of the carrier is interrupted between the positions a and b or between the positions b and c, the dotted line in FIG. As shown by f and g, the carrier transmission is maintained so that the radio wave of the channel #n is not used by others.

In the description of the above embodiment, it is assumed that one controller processes the channel acquisition sequence, data transmission, and response reply from each of a plurality of terminals in a time-division manner as long as there is an idle state. Explained. However, in some systems, for example, when the number of terminals is sufficiently large, a plurality of controllers are provided under a single host device, and a plurality of terminals are associated with each controller. . The situation where the radio wave for the above-mentioned response is used by another terminal is as follows.
This also occurs in the above-described system in which a plurality of controllers communicate with a plurality of terminals. From this, it goes without saying that the present invention can be simultaneously applied to a system in which a plurality of controllers exist.

〔The invention's effect〕

As described above, according to the present invention, the radio wave of channel #n for returning the response reply is not likely to be obtained by another terminal, although the reply reply needs to be returned.

[Brief description of the drawings]

FIG. 1 is a block diagram of the principle of the present invention, FIG. 2 is a configuration of a controller, FIG. 3 is a processing flowchart in the case of the present invention, FIG. 4 is a time chart in the case of the present invention, and FIG. FIG. 6 is an explanatory diagram of a conventional case, FIG. 7 is a processing flowchart of a conventional case, and FIG. 8 is a time chart of a conventional case. In the figure, 1 is a controller, 2A and 2B are terminals, 3 is a channel acquisition sequence, 4 is data transmission, 5 is a response reply, 11 is a host device, 12 is a wireless device, 13 is a data processing unit, and 14 is communication control. And 15, a wireless control unit, 16 a channel selection unit, and 17 a wireless input / output unit.

 ──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-64-1340 (JP, A) JP-A-61-2047 (JP, A) JP-A-62-226741 (JP, A)

Claims (1)

(57) [Claims] A controller (1) and a plurality of terminals (2) are configured to be able to communicate via a plurality of wireless communication channels, and the controller (1) and each of the terminals (2) communicate with each other. In the meantime, the controller (1) and / or the terminal (2) on the data transmitting side searches for a free channel in response to a communication start request from the terminal. If there is no carrier corresponding to each channel, the controller (1) and / or the terminal (2) performs a search. Through a channel acquisition sequence to be acquired as a channel, one of the plurality of channels
A wireless communication system in which the transmitting side transmits data by wireless communication on the channel, and the data receiving side responds by wireless communication on the channel. The controller (1) on the side that has received data by wireless communication by one and / or
Alternatively, the terminal (2) keeps transmitting a carrier corresponding to one of the channels until the terminal (2) returns the response from the terminal (2).