JP2002164901A - Master / slave setting method, communication control device, and network system - Google Patents

Abstract

(57) Abstract: An object of the present invention is to perform a data communication with a high data transfer efficiency by requesting a change of a master terminal when a data signal is transmitted and received between communication control devices serving as slave terminals. The purpose of the present invention is to provide a network system capable of performing the following. When a terminal is set as a slave terminal,
When transmitting a data signal to another communication control device serving as a slave terminal, the master change determination unit 210 has determined that it is better to transmit the data signal after performing the change setting of the master terminal and then to perform data transfer more efficiently. At this time, a master change request signal is transmitted. When the communication control device set as the master terminal receives the master change request signal, the master control unit 206 checks the validity of the change setting of the master terminal.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a communication control device having a communication function, and more particularly to a communication control device capable of mutually setting a master terminal and a slave terminal. The present invention also relates to a network system including such a communication control device and a master / slave setting method.

[0002]

2. Description of the Related Art With the recent development of network-related technology, a system for transmitting and receiving information in a local area using a portable terminal such as a PDA (Personal Digital Assistants) has been realized. This transmission / reception system is used for group communication in a destination space or communication limited to a designated area, and enables mutual communication by automatically recognizing each terminal. A communication network in such a communication system is called an ad hoc network.

In order to realize this ad hoc network, a device technology called Bluetooth has been proposed (see “Transistor Technology 1999.10”, 205-206).
Page, “Overview of Bluetooth”). This Bluetooth device is a device used for a communication control device for constructing a wireless local area network using a 2.4 GHz frequency band. A plurality of communication control devices having this device construct a minimum unit network called a piconet. Then, among the plurality of communication control devices that construct the piconet, one communication control device that has started communication first operates as a master terminal, and the other communication control devices operate as slave terminals. The communication control devices communicate with each other.

In a network constructed by a communication control device using a Bluetooth device in the above document, a method of selecting a communication control device which has started communication first as a master terminal is used as a method of selecting a master terminal. However, in addition to this method, Japanese Patent No. 29248
There is a method provided in JP-A-28. This is a method of selecting an appropriate master device (master terminal) based on the remaining battery capacity and transfer rate of each communication control device in the ad hoc network. By using this method, the connection time of the network is maintained and the transfer efficiency of the network is improved.

[0005]

However, as in the network constructed by the communication control device using the Bluetooth device described above, the communication control device which has started communication first is selected as the master terminal, and the network is established. If communication between slave terminals is frequently performed after the network is established, communication is performed via the master terminal, so that communication is performed between the master terminal and the slave terminal. , The data transfer efficiency decreases.

In Japanese Patent No. 2924828, the master terminal is selected based on the remaining battery capacity and the transfer rate of each communication control device in the network, so that the master terminal can be changed. I have. However, the transfer rate serving as a criterion for selecting a master terminal is the transmission speed when test data is transmitted from each slave terminal to the master terminal. Therefore, when the remaining battery power of each communication control device is equal, the master terminal
It is selected depending on the transmission capability of each communication control device.
Therefore, the master terminal is not selected based on the transfer time required for actual communication, and as a result, the result becomes the same as when the master terminal is established, which may not improve the transfer efficiency of the network.

[0007] In view of the above problems, the present invention provides a data communication with high data transfer efficiency by requesting a change of a master terminal when a data signal is transmitted and received between communication control devices serving as slave terminals. The purpose of the present invention is to provide a network system capable of performing the following. Also, the present invention
It is an object to provide a communication control device and a master / slave setting method for constructing such a network system.

[0008]

In order to achieve the above object, a master / slave setting method according to the present invention provides a method for setting one communication control device serving as a master terminal in a network constructed by a plurality of communication control devices. In a master / slave setting method for setting an apparatus and a plurality of communication control apparatuses serving as slave terminals, in a currently constructed network, a communication control apparatus which is an arbitrary slave terminal in the network is connected to another slave. When a data signal is transmitted to a communication control device that is a terminal, one of the two communication control devices that are slave terminals that transmit and receive the data signal is changed to a master terminal, and a new master terminal is changed. And resetting the slave terminal.

According to such a master / slave setting method, when data communication is performed between two communication control devices serving as slave terminals, data communication is performed via the communication control device serving as a master terminal. The setting of one of the two communication control devices for performing the data communication can be changed to the master terminal. Therefore, two communication control devices that perform data communication can directly perform data communication.

Further, in such a master / slave setting method, two communication control devices, which are slave terminals for transmitting and receiving the data signal, communicate with each other via the communication control device currently set as the master terminal. The first data transfer time required for transmission / reception is calculated, and after the change of the master terminal is started, the two communication control devices, which are slave terminals for transmitting / receiving the data signal, are respectively connected to the master terminal. After being set as a slave terminal, a second data transfer time required for the two communication control devices to directly transmit and receive the data signal is calculated, and the second data transfer time is calculated from the first data transfer time. When it becomes shorter, the master terminal is changed so that a network with high data transfer efficiency can be constructed. Can.

A communication control device according to the present invention is a communication control device which constructs a network together with a plurality of other communication control devices and performs data communication as either a master terminal or a slave terminal in the network. And a transmission / reception unit for transmitting / receiving a signal, and when set as a slave terminal, transmits a data signal to another communication control device set as a slave terminal among other communication control devices configuring the network. At this time, whether to change either the own device or the communication control device of the transmission destination of the data signal to the master terminal so that a master change signal for requesting the change of the master terminal is generated in the transmission / reception unit And a master change determining unit for determining whether the master terminal is changed by the master change determining unit. When it is determined, after generating the master change request signal by the transmitting and receiving unit, and transmits the master change request signal to another communication controller that is currently set to the master terminal.

In this manner, when the communication terminal is set as the slave terminal, the data communication with the other communication control device set as the slave terminal is performed via the other communication control device set as the master terminal. When communication is performed, a master change request signal can be transmitted to another communication control device set as a master terminal. Therefore, direct data communication can be performed between the own device and a partner device that performs data communication.

Further, the communication control device of the present invention is a communication control device which constructs a network together with a plurality of other communication control devices and performs data communication as one of a master terminal and a slave terminal in the network. A transmission / reception unit for transmitting / receiving a signal for communication, and when set as a master terminal, a master change request signal for requesting a change of a master terminal transmitted from another communication control device serving as a slave terminal. When received by the transmitting and receiving unit, while canceling the setting as the master terminal, the master change notification signal for recognizing that the other communication control device to be set to the master terminal next performs setting of the master terminal, A master control unit that controls the transmission / reception unit to generate the data, and a communication unit between the other communication control devices serving as slave terminals. When communication of the data signal is about to be started, when the master change request signal is transmitted from another communication control device that is a slave terminal that transmits the data signal, the master control unit operates as a master terminal. After the setting is canceled, the master change notification signal is transmitted to another communication control device to be set as the next master terminal.

By doing so, when another communication control device set as two slave terminals tries to perform data communication via its own device when it is set as a master terminal, After releasing the setting of the own device as the master terminal, a master change notification signal is transmitted to change the setting of one of the two other communication control devices that perform data communication to the master terminal. Therefore, two other communication control devices that perform data communication can directly perform data communication.

Further, the communication control device of the present invention is a communication control device which constructs a network together with a plurality of other communication control devices and performs data communication as one of a master terminal and a slave terminal in the network. A transmission / reception unit for transmitting / receiving a signal for communication, and when set as a slave terminal, sends a data signal to another communication control device set as a slave terminal among other communication control devices configuring the network. At the time of transmission, one of the own device or the communication control device of the transmission destination of the data signal is changed to the master terminal so that a master change signal for requesting a change of the master terminal is generated in the transmission / reception unit. A master change determination unit that determines whether or not a master terminal is set,
When the transmission / reception unit receives the master change request signal transmitted from another communication control device serving as a slave terminal, the setting as the master terminal is released, and the other communication control device set to the next master terminal is reset. And a master control unit that controls a master change notification signal for causing the transmission / reception unit to generate a master change notification signal for recognizing that setting of the master terminal is performed. When it is determined that the change of the master terminal is performed by the change determination unit, the transmission / reception unit generates the master change request signal, and then transmits the master to another communication control device that is currently set to the master terminal. A change request signal is transmitted, and when set as a master terminal, the master change is performed between other communication control devices that are slave terminals. When the request signal is transmitted, the master control unit cancels the setting as the master terminal, and then transmits the master change notification signal to another communication control device set as the next master terminal. And

When such a communication control device transmits the data signal to the destination communication control device via the communication control device currently set as the master terminal in the master change determination section, The first data transfer time is calculated, and the second data transfer time required from when the generation of the master change request signal is started to when the data signal is transmitted to the destination communication control device is calculated. And the second data transfer time is the first data transfer time.
When the time is shorter than the data transfer time, whether the master terminal is changed or not is changed by determining that the change of the master terminal is performed. Is determined. Therefore, a network with high data transfer efficiency is constructed by this communication control device.

In such a communication control device, in order to identify a communication control device set as a master terminal and a communication control device set as a slave terminal in a network, a communication control device for identifying each communication control device is identified. A terminal identification information storage unit that stores terminal identification information, and a slave information storage unit that stores slave identification information that is terminal identification information of another communication control device set as a slave terminal when the network is constructed. A master identification information storage unit that stores master identification information that is terminal identification information of another communication control device set as a master terminal when the network is established.

In this communication control device, when the master terminal is changed, the slave identification information in the slave information storage and the master identification information in the master identification information storage are deleted, and the slave information storage and the master are deleted. After the identification information storage section is reset, the apparatus enters a standby state.

In the case where the communication terminal is set as a slave terminal in the network and is set as a master terminal after changing the master terminal, the master change communication from the communication control device set as the master terminal in the network is performed. When a slave signal is received, the slave information storage unit and the master identification information storage unit are reset to be in a standby state, and then set to a master terminal.

In the case where the communication terminal is set to the master terminal, the transmission / reception section searches for another communication control device and generates a search signal for recognizing that the communication terminal has been set to the master terminal. Sent to the device,
When receiving a reply signal to the search signal transmitted from another communication control device, by storing the terminal identification information included in the reply signal in the slave information storage unit as the slave identification information, Recognize another communication control device set to, and, when set to a slave terminal, receive a search signal transmitted from another communication control device set to the master terminal, and within the search signal By storing the included terminal identification information as the master identification information in the master identification information storage unit, another communication control device set in the master terminal is recognized, and the reply signal to the search signal is transmitted to the transmission / reception unit. , And may be transmitted to another communication control device set in the master terminal.

The network system of the present invention is set as a slave terminal in a network system constructed by a communication control device set as one master terminal and a plurality of communication control devices set as slave terminals. When the communication control device transmits a data signal to the communication control device set as another slave terminal, it determines whether or not to change the setting of the master terminal based on the time required for transmitting and receiving the data signal. After the determination, when it is determined that it is necessary to change the settings of the master terminal,
2 set as a slave terminal that performs transmission and reception
A master change request signal for requesting that any one of the communication control devices be set to be changed to the master terminal is transmitted to the communication control device set as the master terminal.

In such a network system, when two communication control devices set as slave terminals attempt data communication via a communication control device set as a master terminal, a data signal is transmitted. A request for a master change request is transmitted from the communication control device that performs the data communication, and one of the two communication control devices that intends to perform the data communication is requested to change the setting to the master terminal. Therefore, by changing the master terminal, direct data communication can be performed between the two communication control devices set as the slave terminals.

In such a network system, when two communication control devices, which are slave terminals for transmitting and receiving the data signal, transmit and receive the data signal via a communication control device set as a master terminal. The first data transfer time is calculated, and after the change of the master terminal is started, the two communication control devices, which are the slave terminals that transmit and receive the data signal, are set to the master terminal and the slave terminal, respectively. After that, a second data transfer time required for the two communication control devices to directly transmit and receive the data signal is calculated, and when the second data transfer time is shorter than the first data transfer time, By transmitting the master change request signal, it is possible to always configure a network with high data transfer efficiency. Kill.

When the communication control device set as the master terminal receives the master change request signal,
Releases the setting of the master terminal of the own device, and transmits a master change notification signal for recognizing that the communication terminal is set as the master terminal to the communication control device set as the next master terminal, and Make the change settings for.

When a network is first constructed, a communication control device set to be a master terminal transmits a search signal for searching for another communication control device which is powered on and is in a standby state. The other communication control device that has received the search signal is set as a slave terminal.

When reconfiguring the network by changing the communication control device serving as the master terminal, first, all communication control devices forming the network are set to a standby state, and then the master change notification signal is transmitted. A search signal for searching for another communication control device in a standby state is transmitted from the communication control device that has been received and newly set to be the master terminal, and another communication control device that has received the search signal Is set as a slave terminal.

[0027]

Embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing the internal configuration of the communication control device according to the present embodiment. or,
FIG. 2 is a block diagram showing a functional configuration of the communication control device of FIG.

<Configuration of Communication Control Device> The communication control device shown in FIG. 1 has a CPU (Central
(Processing Unit) 101, a ROM (Read Only Memory) 102 in which various software and data such as a program for operating each unit are stored, and a RAM (Random Acces) in which data necessary for processing in each unit is temporarily stored.
s Memory) 103. Therefore, the CPU 101 reads and writes software and data stored in the ROM 102 and operates, and reads and writes data in the RAM 103, so that the CPU 101 controls and manages operations of each unit in the communication control device.

The communication control device shown in FIG. 1 includes an input unit 104 for inputting various data from the outside, an output unit 105 for outputting data to the outside, an input unit 104 and an output unit 1
And an I / O (Input / Output) device 106 for enabling data exchange between the CPU 05 and the CPU 101. Therefore, when data is input by operating the input unit 104 by the user, the data is
The data is converted into data that can be processed by the CPU 101 by the O device 106 and transmitted to the CPU 106. Also, the CPU 10
6 sends data to the I / O device 106.
The I / O data 106 is converted into data that can be processed by the output unit 105 and output to the output unit 105.

Further, the communication control device shown in FIG. 1 includes an external storage device 107 such as a hard disk drive for storing various data, a communication device 108 for encoding, decoding, and modulating / demodulating data, and another communication control device. An antenna 109 for transmitting and receiving signals to and from the device is provided. Therefore, the data that the user wants to save is stored in the external storage device 107 by being stored. In addition, data to be transmitted to another communication control device is encoded by the communication device 108 and then modulated to generate a transmission signal, and the transmission signal is transmitted from the antenna 109 to another communication control device.
Also, the signal transmitted from another communication control device is
09, and the received signal is demodulated by the communication device 108 and then decoded, so that the data is processed by the CPU 101.

The communication control device having such a configuration has a functional configuration as shown in FIG. 2 for use in an ad hoc network system. That is, the communication control device includes a control unit 201 for controlling operation of each function, a data transmission / reception unit 202 controlled by the control unit 201, an identification information control unit 203, a master control unit 206, and an application control unit 208. And a terminal identification information storage unit 204, a master identification information storage unit 205, and a slave information storage unit 211 that are operationally managed by the identification information control unit 203.
A slave information storage unit 207 whose operation is managed by the master control unit 206; and an application control unit 208
A data storage unit 209 and a master change determination unit 210 whose operation is controlled by the control unit.

When each function is configured as described above, the terminal identification information storage unit 204 stores the master identification information storage unit 205 and the slave information storage units 207 and 21 in the ROM 102.
1 is configured in the RAM 103, and the data storage unit 209 is configured in the external storage device 107. Other functional units are provided as functions constituting a program that is executed and controlled by the CPU 101.

Then, the data transmitting / receiving unit 202
The operation management of the communication device 108 is performed, and the communication operation with another communication control device is controlled. Also, the identification information control unit 2
03 manages the operation of the ROM 102 and the RAM 103. Then, reading of the terminal identification information provided individually for each communication control device from the terminal identification information storage unit 204 is controlled. Also, when operating as a slave terminal, the identification information control unit 203 writes and reads terminal identification information of another communication control device serving as a master terminal to / from the master identification information storage unit 205, and reads out another terminal serving as a slave terminal. Writing and reading of the terminal identification information of the communication control device to and from the slave information storage unit 211 are controlled.

The master controller 206 controls the RAM 10
When the operation management of 3 is performed and it operates as a master terminal,
Writing and reading of the terminal identification information of the other communication control device serving as the slave terminal to / from the slave information storage unit 207 are controlled. Further, the external storage device 107 is controlled by the application control unit 208 and the data storage unit 2 is controlled.
The application stored in the application 09 is read out, the processing by this application is performed, and the data obtained by the processing by this application is written and read into the data storage unit 209. Further, the determination operation related to the change of the master terminal by the master change determination unit 210 is controlled.

The data storage unit 209 stores software serving as an application program for performing data processing and data obtained by performing processing by the application. Hereinafter, the software of this application is referred to as “application program”, and data obtained by processing by the application is referred to as “application data”.

The operation of the communication control device having such a functional part will be described below. In addition, FIG.
FIG. 5 is a flowchart showing the operation of each communication control device in this ad hoc network.

<Operation in Standby State> First, from a standby state in which no application data is transmitted / received to / from another communication control device, a data communication state for constructing a network with another communication control device and transmitting / receiving application data. Next, the operation when the communication control device makes a state transition will be described with reference to the flowchart in FIG.

After the power is turned on, the communication control device enters a standby state to establish a network with another communication control device (S301). After that, the application control unit 208
The control unit 201 checks whether or not a request has been made to be set as a master terminal (S302). At this time, when the user operates the input unit 104 to request master setting (Yes), the control unit 201
Recognizes that the own device is the master terminal, and makes a state transition to a search state for searching for another communication control device (S303).

When the state transitions to the search state in this way, the identification information control unit 203 causes the terminal identification information storage unit 204
Is read out. After the communication device 108 is controlled by the data transmitting / receiving unit 202 and a search signal including terminal identification information and master information indicating that the terminal is a master terminal is generated,
The signal is transmitted from the antenna 109 (S304).

Thereafter, it is determined whether a slave identification signal composed of terminal identification information of another communication control device that has received the search signal and recognized as a slave terminal has been received (S305). At this time, the slave identification signal is received by the antenna 109 and the communication device 10
8 (Yes), this communication device 108
The master control unit 206 stores, in the slave information storage unit 207, the terminal identification information of another communication control device obtained by demodulation after decoding in step S30 as slave identification information (S30).
6). Then, it is confirmed whether or not the search for the slave terminal has been performed for a predetermined time (S307). If the slave identification signal has not been received (No), the process directly proceeds to S307.

In step S307, the control unit 20 informs the control unit 20 that a predetermined time has elapsed since the communication control device transitioned to the search state.
When 1 is detected (Yes), the communication control device transitions to a data communication state in which data communication with another communication control device recognized as a slave terminal is possible (S311). or,
If the fixed time has not elapsed since the communication control device transitioned to the search state (No), another search for a communication control device serving as a slave terminal as described above is performed again (S30).
4-S307).

If there is no request for master setting in S302 (No), it is determined whether or not a search signal has been received from another communication control device serving as a master terminal (S3).
08). At this time, if the search signal is not received (N
o), the process proceeds to S302, and the above-described operations after S302 are performed again.

When the search signal is received by the antenna 109 and given to the communication device 108 (Yes), the search signal is demodulated by the communication device 108 and then decoded to obtain the master terminal. The identification information control unit 203 stores the terminal identification information as master identification information in the master identification information storage unit 205 (S309). At this time, the control unit 201 recognizes that the own device is a slave device.

Thereafter, the terminal identification information stored in the terminal identification information storage unit 204 is read by the identification information control unit 203. Then, the communication device 108 is controlled by the data transmission / reception unit 202 to generate a slave identification signal including terminal identification information and slave information indicating that the terminal is a slave terminal, and then the slave identification signal is transmitted from the antenna 109 (S310). . Then, after transmitting the slave identification signal, the state shifts to a data communication state in which data communication with another communication control device recognized as the master terminal is possible (S311).

Accordingly, when one communication control device in the standby state transmits a search signal, and among the plurality of communication control devices in the standby state, the search signal is received and a slave identification signal is returned, The communication control device that has transmitted the signal becomes the master terminal, and the plurality of communication control devices that have transmitted the slave identification signal become the slave terminals, thereby forming a network for exchanging communication with each other.

<Operation of Master Terminal in Data Communication State> Next, when the state transitions to the data communication state, the operation of the communication control device operating as the master terminal will be described with reference to FIG.
This will be described with reference to the flowchart of FIG.

As described above, when the input unit 104 is operated and the communication control device set as the master terminal transitions to the data communication state (S401), first, the slave identification information stored in the slave information storage unit 207 is read. The data is read by the master control unit 206. Then, a slave information signal having a plurality of pieces of slave identification information is generated by the communication device 108 and transmitted from the antenna 109 (S402). afterwards,
It is determined whether a master change request signal requesting a change of the master terminal has been transmitted from another communication control device operating as a slave terminal (S403). At this time, if the master change request signal has not been received (No), the flow shifts to S409 to confirm reception of a data signal from another communication control device serving as a slave terminal.

The master change request signal is transmitted to the antenna 109.
Is received and given to the communication device 108 (Ye
s) The validity of the change of the master terminal is determined by the master control unit 206.
Is verified (S404). At this time, by comparing the terminal identification information of the communication control device that has transmitted the master change request signal with the slave identification information stored in the slave information storage unit 207, the communication control device that has transmitted the master change request signal is controlled by the control unit. Recognize at 201. Also, the master change request signal has terminal identification information for designating the communication control device to be set as the next master terminal, and this terminal identification information is stored in the slave information storage unit 207 stored in the slave information storage unit 207. By collating with the identification information, the control unit 201 recognizes the communication control device set as the next master terminal.

When the master control unit 206 determines in S404 that the master terminal does not need to be changed (No), the flow shifts to S409 to receive data from another communication control device serving as a slave terminal. Is confirmed.
When the master control unit 206 determines that the change of the master terminal is appropriate (Yes), the communication control device other than the communication control device to be set next as the master terminal is transmitted to the plurality of communication control devices serving as slave terminals. A master deletion notification signal for deleting the master identification information stored in the master identification information storage unit 205 of each communication control device is transmitted (S40).
5). At this time, the control unit 201 controls the communication device 108 to generate a master deletion notification signal, and the generated master deletion notification signal is transmitted from the antenna 109.

As described above, when the master deletion notification signal is transmitted, the master control unit 206 deletes all the slave identification information stored in the slave information storage unit 207 (S406). Then, finally, a master change notification signal is transmitted to the communication control device set as the next master terminal so that the master terminal setting request is made (S407). At this time, the control unit 20
By 1, the communication device 108 is controlled to generate a master change notification signal, and the generated master change notification signal is transmitted from the antenna 109. Thereafter, the communication control device makes a state transition to the standby state (S408).

In S409, when it is confirmed that a data signal from another communication control device serving as a slave terminal is received by the antenna 109 (Yes), the data is transmitted to the own device from the terminal identification information transmitted together with the data. It is determined whether the received data signal is a data signal for performing the operation (S410). or,
When the reception of the data signal from another communication control device serving as the slave terminal is not confirmed in S409 (No), it is determined whether the data communication process is completed (S41).
3).

In S410, if the data signal is transmitted to the own device (Yes), the communication device 108
After being demodulated and decoded into data that can be processed by the CPU 101, the data is stored in the data storage unit 209 by the application control unit 208 (S411). If the data signal is to be transmitted to another communication control device serving as a slave terminal (No), the data signal is transmitted to the communication device 108 and the antenna 1 to the slave terminal.
09 (S412).

After the processing operations of S411 and S412 are performed, it is determined whether or not the data communication processing has been completed (S413). Then, when the data communication is terminated (Yes), after resetting various information in the RAM 103 (S414), the state transitions to the standby state (S408),
When data communication is continued (No), S403
Then, the operation after S403 is performed again.

Therefore, the communication control device that operates as the master terminal when the state transitions to the data communication state receives the master change request signal from one of the communication control devices serving as a plurality of slave terminals forming the network. When
First, it is determined whether the master terminal needs to be changed. And when it is determined that the master terminal needs to be changed,
First, a master deletion notification signal is transmitted to the communication control device that remains as a slave terminal even after the change. Next, after deleting all the slave identification information stored in the own device, a master change notification signal is transmitted to the communication control device that becomes the master terminal after the change, and the state transitions to the standby state.

<Operation of Slave Terminal in Data Communication State> Next, when the state transitions to the data communication state, the operation of the communication control device operating as a slave terminal will be described.
This will be described with reference to the flowchart of FIG.

As described above, when the input control unit 104 is operated to change the communication control device set as the master terminal to the data communication state (S501), first, the slave information signal is transmitted from the master terminal device to the communication device 108 and the antenna. The slave identification information, which is received at 109 and is terminal identification information to be a slave terminal other than the own device, is stored in the slave information storage unit 211 by the identification information control unit 203 (S502).

Thereafter, the control unit 201 determines whether or not the input unit 104 has been operated to request transmission of the application data or application program stored in the data storage unit 209 (S503). At this time, if a transmission request has not been made by the input unit 104 (No), the process proceeds to S507, where a master deletion notification signal transmitted from another communication control device serving as a master terminal is confirmed.

When a transmission request is made by the input unit 104 (Yes), the application control unit 20
In step S504, the outline of the data to be transmitted is determined, and the master change determination unit 210 determines whether the master terminal needs to be changed (S504). At this time, when it is determined that the change of the master terminal is necessary (Yes), the application control unit 2
08, a control signal is given to the communication device 108,
After a master change request signal is generated by the communication device 108, the master change request signal is transmitted from the antenna 109 to the communication control device serving as a master terminal (S505). After that, the flow shifts to S507, where a master deletion notification signal transmitted from another communication control device serving as a master terminal is confirmed. When the master change request signal is transmitted in S505, the master change request signal includes the terminal identification information of the communication control device to be changed to the master terminal.

When it is determined that it is not necessary to change the master terminal (No), the application data or application program in the data storage unit 209 is supplied from the application control unit 208 to the communication device 108, and then transmitted from the antenna 109. It is transmitted to the communication control device serving as the master terminal (S506). After that, the flow shifts to S507, where a master deletion notification signal transmitted from another communication control device serving as a master terminal is confirmed. When the data signal is transmitted in S506, the data signal includes the terminal identification information of the communication control device that is the transmission partner.

In S507, when the master deletion notification signal is received by the antenna 109 and given to the communication device 108 (Yes), the identification information control unit 203
The terminal identification information serving as the master identification information stored in the master identification information storage unit 205 is deleted (S508). Then, after deleting the terminal identification information serving as the slave identification information stored in the slave information storage unit 211 (S509),
The state transitions to the standby state (S510). When the master deletion notification signal has not been received (No), a master change notification signal transmitted from another communication control device serving as a master terminal is confirmed (S511).

The master change notification signal is transmitted to the antenna 1
09 and is given to the communication device 108 (Yes), the identification information control unit 203 deletes the terminal identification information serving as the master identification information stored in the master identification information storage unit 205 (S512). The terminal identification information serving as the slave identification information stored in the information storage unit 211 is deleted (S513). Thereafter, the control unit 201 operates so that the input unit 104 is operated to be in the same state as when the input is performed so that the master terminal is set (S514).
The state transitions to the standby state (S510).

When the master change notification signal has not been received (No), it is determined whether or not the data communication processing has been completed (S515). At this time, when the data communication is terminated (Yes), various kinds of information in the RAM 103 are reset (S516), and the state transits to the standby state (S51).
0) When data communication is continued (No), S
The flow shifts to 503, and the operation after S503 is performed again.

Therefore, the communication control device which operates as a slave terminal when the state transition to the data communication state and which is set as the master terminal after changing the master terminal is notified of the master change by the communication control device which is the master terminal forming the network. Receive the signal. After deleting all the master identification information and the slave identification information stored in the own device, the input unit 10 is set so as to be set in the master terminal.
4. Make the same state as when 4 was operated. Therefore, when the state transitions to the standby state, it is determined that the master setting request has been made in S302 of FIG. 3, and the state transition can be made to the search state.

Further, the communication control device which operates as a slave terminal when the state transits to the data communication state and which operates as a slave terminal even after the master terminal is changed, receives a master deletion notification from the communication control device which is the master terminal for constructing the network. Receive the signal. Then, after all the master identification information and the slave identification information stored in the own device are deleted, the state transitions to the standby state.

In the flowchart of FIG. 4 described above, only the data signal receiving operation of the master terminal is shown, and in the flowchart of FIG. 5, only the data signal transmitting operation of the slave terminal is shown. However, this is for explaining the operation flow at the time of changing the master terminal in which the slave terminal transmits the master change request signal and the master terminal receives the master change request signal. Therefore, the master terminal performs a data signal transmitting operation together with the data signal receiving operation shown in the flowchart of FIG.
The data signal receiving operation is performed together with the data signal transmitting operation shown in the flowchart of FIG.

<Master Terminal Change Processing> A method for determining the necessity of changing the master terminal will be described below with reference to FIGS. 6 and 7.

When a network is constructed by a plurality of communication control devices that have transitioned to the data communication state, application data will be transmitted from a communication control device serving as a slave terminal to another communication control device also serving as a slave terminal. Then, the master change determination unit 210 determines the necessity of changing the master terminal. As described above, when data communication is performed by the communication control device serving as the slave terminal, data communication is performed via the communication control device serving as the master terminal. That is, first, a data signal is transmitted from the slave terminal serving as a transmission source to the master terminal. Thereafter, the data signal is transmitted from the master terminal to the slave terminal that is the transmission destination.

At this time, the master change determination section 210
First, a data transfer time Ta, which is a time for transmitting application data from its own device, which is a slave terminal serving as a transmission source, to a master terminal, and a data transfer time, which is a time for transmitting application data from the master terminal to a slave terminal which is a destination. The time Tb is calculated based on the data amount of the application data. Then, when the master terminal is not changed, the data transfer time Ta + Tb shown in FIG. 6 for transmitting the application data to the slave terminal as the transmission destination via the master terminal is calculated.

Next, after the own device is changed to the master terminal, a data transfer time Td which is a time for transmitting the application data to the slave terminal as the transmission destination is calculated. Then, by adding the master change time Tc required for changing the master terminal, the data transfer time Tc + Td shown in FIG. 6 for transmitting data to the slave terminal that is the destination after the master terminal change is calculated.

Note that the master change time Tc is determined by temporarily setting all the communication control devices in the network in the data communication state to the standby state and then setting the communication control device operating as the slave terminal before the transition to the standby state. This corresponds to the time from when one of them is determined as the master terminal again and the network is reconstructed, and is set in advance when the network is constructed.

The data transfer time Ta + Tb when there is no change in the master terminal and the data transfer time Tc + Td when there is a change in the master terminal are compared, and the data transfer time Tc + Td becomes shorter. A master change request signal is generated and transmitted by the communication device 108 so that the master terminal is changed.

When the application data is transmitted to the destination slave terminal, the application program is not stored in the data storage unit 209 of the destination slave terminal.
In some cases, this cannot be performed by the PU 101. At this time, the transmission destination slave terminal sends a transmission request of the application program to the transmission source slave terminal via the master terminal.

At this time, the transmission source slave terminal transmits the application program to the transmission destination slave terminal via the master terminal, and then transmits the application data again to the transmission destination slave terminal via the master terminal. That is, after the application program is transmitted from the transmission source slave terminal to the master terminal, the application program is transmitted from the master terminal to the transmission destination slave terminal and stored in the data storage unit 209 of the transmission destination slave terminal.

After the application data is transmitted from the transmission source slave terminal to the master terminal, the application data is transmitted from the master terminal to the transmission destination slave terminal. In this way, in the slave terminal of the transmission destination, the application control unit 208 performs data processing on the transmitted application data using the previously transmitted application program.

At this time, the master change judgment section 210
First, a data transfer time ta, which is a time for transmitting an application program from its own device, which is a slave terminal serving as a transmission source, to a master terminal, and a data transfer time, which is a time for transmitting an application program from a master terminal to a slave terminal which is a transmission destination A time tb, a data transfer time Ta which is a time for transmitting the application data from the own device which is a transmission source slave terminal to the master terminal,
Data transfer time Tb that is the time for transmitting application data from the master terminal to the slave terminal that is the destination
Are calculated based on the data amount of the application program and the application data.

When the master terminal is not changed, the data transfer time ta shown in FIG. 7 for transmitting the application program and the application data to the slave terminal as the transmission destination via the master terminal.
+ Tb + Ta + Tb is calculated.

Next, after the own device is changed to the master terminal, the data transfer time tc, which is the time for transmitting the application program to the slave terminal, which is the transmission destination, and the application data is transmitted to the slave terminal, which is the transmission destination. A data transfer time Td which is a time is calculated. Then, by adding the master change time Tc required for changing the master terminal, the data transfer time tc + Tc + Td shown in FIG. 7 for transmitting data to the slave terminal serving as the destination after the master terminal change is calculated.

As in the case of FIG. 6, the master change time T
c, after temporarily setting all communication control devices in the network in the data communication state to the standby state, one of the communication control devices operating as slave terminals before the transition to the standby state is set as the master terminal. This corresponds to the time until it is determined again and the network is reconstructed, and is set in advance when the network is constructed.

The data transfer time ta + tb + Ta + T when there is no change in the master terminal calculated in this way.
b and data transfer time t when the master terminal is changed
c + Tc + Td, and the data transfer time tc + Tc
When + Td becomes shorter, a master change request signal is generated and transmitted by the communication device 108 so that the master terminal is changed.

When the communication control device serving as the master terminal receives the master change request signal, the master control unit 2
At 06, the validity of the master change is verified. At this time,
If the master terminal performs data communication with another slave terminal other than the data communication that the slave terminal that transmits the master change request signal is trying to perform, it is determined that there is no need to change the master.

<Operation When Applied to Ad Hoc Network> Next, an ad hoc network constructed by a plurality of communication control devices described above will be described below. FIGS. 8 and 9 are configuration examples of an ad hoc network constructed by four communication control devices, respectively.

When the input unit 104 of the communication control terminal A is operated among the communication control devices A, B, C, and D in the power-on and standby state, and the communication control device A has a master setting request. , The communication control device A makes a state transition to the search state,
The transmission of the search signal is continued for a predetermined time. Then, the communication control devices B to B that have received the search signal from the communication control terminal A
D respectively stores the master identification information corresponding to the terminal identification information of the communication control terminal A in the master identification information storage unit 205, and then transmits a slave identification signal to the communication control device A to change the data communication state. State transition.

When the communication control device A in the search state receives the slave identification signal from each of the communication control devices B to D, each time the communication control device A receives the slave identification signal, it transmits the slave identification information corresponding to the terminal identification information to the slave information. Storage unit 207
To be stored. Then, when confirming that a predetermined time has passed since the state transition to the search state, the communication control device A makes a state transition to the data communication state. As described above, when the communication control device A that has transitioned to the search state receives the slave identification signals from the communication control devices B to D within a predetermined time, as shown in FIG. An ad hoc network 800 in which the communication control devices BD are slave terminals is constructed.

As described above, when the ad hoc network 800 is constructed by the communication control units A to D, the slave identification information stored in the slave information storage unit 207 of the communication control unit A is transmitted to the communication control units B to D. You. The slave identification information corresponding to the terminal identification information of the communication control devices C and D is stored in the slave information storage unit 211 of the communication control device B, and the terminal information of the communication control devices B and D is stored in the slave information storage unit 211 of the communication control device C. The slave identification information corresponding to the identification information is stored in the slave information storage unit 21 of the communication control device D.
1 stores slave identification information corresponding to the terminal identification information of the communication control devices B and C, respectively.

Thus, in the ad hoc network 800 composed of the communication control devices BD serving as slave terminals and the communication control device A serving as a master terminal, application data and application programs are transmitted from each communication control device. When the transmitted signal
The terminal identification information of the communication control device of the transmission source and the terminal identification information of the communication control device of the transmission destination are included.

Therefore, the communication control device A serving as the master terminal
Stores the terminal identification information included in the transmission signals from the communication control devices BD serving as the slave terminals in the slave information storage unit 2.
07, the communication control device serving as the transmission source and the communication control device serving as the transmission destination are recognized by checking the slave identification information of each slave terminal in 07 and the terminal identification information of the own device in the terminal identification information storage unit 204. Can be.

For example, when application data or an application program is transmitted from the communication control device B to the communication control device C, the communication control device B sends the communication control device A And the data transfer time from the communication control time A to the communication control device C are calculated, and the data transfer time when the master change is not performed (Ta in FIG. 6).
+ Tb, corresponding to ta + tb + Ta + Tb in FIG. 7).

Thereafter, the data transfer time from the communication control device B to the communication control device C is calculated, and the data transfer time (Tc + Td in FIG. 6) for performing the master change in which the master change time required for changing the master terminal is added. , Tc + in FIG.
Tc + Td) is calculated. Then, the calculated data transfer time when not performing the master change is compared with the data transfer time when performing the master change, and when the data transfer time when performing the master change is short, the communication control device B is connected to the master terminal. Is transmitted to the communication control device A as the master terminal.

Upon receiving the master change request signal, the communication control device A stores the terminal identification information of the transmission source communication control device B included in the master change request signal in the slave information storage unit 2.
07 by comparing with the slave identification information stored in
It recognizes that the transmission source is the communication control device B. Also, by comparing the terminal identification information of the communication control device B changed and set to the master terminal included in the master change request signal with the slave identification information stored in the slave information storage unit 207, the communication changed and set to the master terminal is performed. It recognizes that the control device is the communication control device B.

In addition to the data communication between the communication control units B and C, the communication control unit A
When no data communication is performed with .about.D, the master control unit 206 determines that it is necessary to change the master terminal to the communication control device B. Therefore, after transmitting the master deletion notification signal to the communication control devices C and D, the slave identification signal in the slave information storage unit 207 is deleted next. Then, after transmitting the master change notification signal to the communication control apparatus B, the state transition is made to the standby state.

As described above, when the communication control devices C and D receive the master deletion notification signal after the master deletion notification signal and the master change notification signal are transmitted from the communication control device A,
After deleting the master identification information in the master identification information storage unit 205 and deleting the slave identification information in the slave information storage unit 211, the state transitions to the standby state. When the communication control device B receives the master change notification signal, it deletes the master identification information in the master identification information storage unit 205 and the slave identification information in the slave information storage unit 211. Thereafter, the communication control device B sets the same state as the state where the input unit 106 is operated so as to be set as the master, and then makes a state transition to the standby state.

As described above, when all of the communication control devices A to D transit to the standby state, the state of the communication control device B transits to the search state because the communication control device B is set to the master setting state, and the search signal is transmitted. Transmit to the control devices A, C, D. Then, the communication control devices A, C,
After recognizing that the communication control measure B has become the master terminal, each D transmits a slave identification signal to the communication control device B that becomes the master terminal, and makes a state transition to the data communication state.

When the communication control device B receives the slave identification signal transmitted from each of the communication control devices A, C, and D, it recognizes the communication control devices A, C, and D serving as the slave terminals and enters the data communication state. State transition. As described above, when the ad hoc network 900 is constructed by the communication control device B serving as a master terminal and the communication control devices A, C, and D serving as slave terminals as shown in FIG.
The slave identification information in the slave information storage unit 207 is transmitted to C and D. After that, the communication control device B transmits the application data and the application program to the communication control device C.

In this example, the ad hoc network is constructed by four communication control devices.
The number of communication control devices that construct the ad hoc network is not limited to these four. When a master change request signal is transmitted and an ad hoc network is reconstructed, a communication control device that does not perform data communication may be excluded from the newly constructed ad hoc network.

In the present embodiment, the master deletion signal and the master change signal are separately generated, but only the master change signal may be used. At this time, when the communication control device operating as a slave terminal other than the communication control device changed to the master terminal receives the master change signal, the communication control device is changed to the master terminal included in the master change signal. By confirming that the terminal itself is not changed to the master terminal by confirming the terminal identification information, only the master identification information and the slave identification information are deleted, and the state can be changed to the standby state.

In this embodiment, a network setting program for setting a master terminal and a slave terminal configured in one network as described above is previously stored in the communication control device as hardware or software. Although provided, the configuration is not limited to such a configuration.

That is, for example, such a network setting program is stored in the server, and the user accesses the server from the communication control device using various communication lines, and stores the network setting program stored in the server. The program may be downloaded to the communication control device so that the network setting program can be used. Further, the network setting program may be made available by installing from a recording medium storing the network setting program.

[0098]

According to the present invention, when a data signal is to be transmitted and received between two slave communication terminals and a set communication control device, the data signal is composed of a large amount of data. If the data transfer efficiency is lower when communication is performed via the master terminal than when direct communication is performed by changing the master terminal, such as when the data signal is transmitted and received multiple times, try to transmit and receive data signals. One of the two communication control devices can be set as the master terminal to reconstruct the network. Therefore, in the network, the setting of the master terminal can be appropriately changed so that the data transfer efficiency becomes the best. Therefore, a network in which the data transfer efficiency is always high is configured, and the load on the entire network is suppressed. be able to.

[Brief description of the drawings]

FIG. 1 is a block diagram showing the internal configuration of a communication control device according to the present invention.

FIG. 2 is a block diagram showing a functional configuration of a communication control device according to the present invention.

FIG. 3 is a flowchart showing the operation of the communication control device of the present invention.

FIG. 4 is a flowchart showing the operation of the communication control device of the present invention.

FIG. 5 is a flowchart showing the operation of the communication control device of the present invention.

FIG. 6 is a diagram for explaining comparison of data transfer times in a master change determination unit.

FIG. 7 is a diagram for explaining comparison of data transfer times in a master change determination unit.

FIG. 8 is a block diagram showing a configuration of an ad hoc network.

FIG. 9 is a block diagram showing a configuration of an ad hoc network.

[Explanation of symbols]

 101 CPU 102 ROM 103 RAM 104 Input unit 105 Output unit 106 I / O device 107 External storage device 108 Communication device 109 Antenna 201 Control unit 202 Data transmission / reception unit 203 Identification information control unit 204 Terminal identification information storage unit 205 Master identification information storage unit 206 Master control unit 207 Slave information storage unit 208 Application control unit 209 Data storage unit 210 Master change determination unit 211 Slave information storage unit

Continued on the front page F term (reference) 5K033 AA01 AA03 CB11 DA01 EA05 5K034 AA02 AA07 DD03 EE03 EE10 HH01 HH02 KK28 LL01 MM21 NN11

Claims (18)

[Claims] 1. A master / slave setting for setting one communication control device serving as a master terminal and a plurality of communication control devices serving as slave terminals in a network constructed by a plurality of communication control devices. In the method, when a communication control device which is an arbitrary slave terminal in the currently constructed network transmits a data signal to a communication control device which is another slave terminal in the network, transmission and reception of the data signal are performed. A master / slave setting method, characterized in that one of the two communication control devices which is a slave terminal to be performed is changed to a master terminal, and the master terminal and the slave terminal are newly set. 2. The first data transfer when two communication control devices, which are slave terminals that transmit and receive the data signal, transmit and receive data signals via a communication control device that is currently set as a master terminal. The time is calculated, and after the change of the master terminal is started, after the two communication control devices that were the slave terminals that transmit and receive the data signal are set to the master terminal and the slave terminal, respectively,
A second data transfer time required for the two communication control devices to directly transmit and receive the data signal is calculated. When the second data transfer time is shorter than the first data transfer time, a change of a master terminal is performed. The master / slave setting method according to claim 1, wherein 3. When the network is first constructed, a communication control device set to be a master terminal
2. A search signal for searching for another communication control device that is turned on and is in a standby state is transmitted, and the other communication control device that has received the search signal is set as a slave terminal. Or the master / slave setting method according to claim 2. 4. When the master terminal is changed and the network is reconfigured, first, all communication control devices forming the network are set to a standby state, and then set to become a new master terminal. A search signal for searching for another communication control device in a standby state is transmitted from the communication control device, and the other communication control device receiving the search signal is set as a slave terminal. 3. The master / slave setting method according to 3. 5. The communication control device set as a master terminal transmitting the search signal receives the search signal and receives a reply signal from the communication control device set as a slave terminal, thereby receiving the reply signal. The master / slave setting method according to claim 3 or 4, wherein the communication control device that has transmitted the signal recognizes that the communication terminal has been set as a slave terminal. 6. A communication control device for constructing a network together with a plurality of other communication control devices and performing data communication as one of a master terminal and a slave terminal in the network for transmitting and receiving communication signals. A transmission / reception unit, when set as a slave terminal, when transmitting a data signal to another communication control device set as a slave terminal among the other communication control devices configuring the network, changing the master terminal A master that determines whether to change one of its own device or the communication control device to which the data signal is transmitted to a master terminal so that a master change signal for requesting the data is generated by the transmission / reception unit And a change determination unit, wherein when the master change determination unit determines that the change of the master terminal is performed, After generating the master change request signal transmitting and receiving unit, a communication control apparatus and transmits the master change request signal to another communication controller that is currently set to the master terminal. 7. The first data transfer time required for transmitting the data signal to the communication control device of the transmission destination via the communication control device currently set as a master terminal in the master change determination unit. Is calculated, and a second data transfer time required from when the generation of the master change request signal is started to when the data signal is transmitted to the communication control device of the transmission destination is calculated, and the second data 7. The communication control device according to claim 6, wherein when the transfer time becomes shorter than the first data transfer time, it is determined that the change of the master terminal is performed. 8. A communication control device for constructing a network together with a plurality of other communication control devices and performing data communication as one of a master terminal and a slave terminal in the network for transmitting and receiving communication signals. When the transmission / reception unit receives a master change request signal for requesting a change of the master terminal transmitted from another communication control device serving as a slave terminal when the transmission / reception unit is set as the master terminal, the master terminal As well as canceling the setting, control is performed such that the transmission / reception unit generates a master change notification signal for recognizing that another communication control device to be set to the master terminal next performs setting of the master terminal. And a master control unit that communicates with another communication control device serving as a slave terminal. When the master change request signal is transmitted from another communication control device serving as a slave terminal that performs transmission of the data signal when the master control unit cancels the setting as the master terminal, Next, the communication control device transmits the master change notification signal to another communication control device set as a master terminal. 9. A communication control device for constructing a network together with a plurality of other communication control devices and performing data communication as one of a master terminal and a slave terminal in the network, for transmitting and receiving communication signals. A transmission / reception unit, when set as a slave terminal, when transmitting a data signal to another communication control device set as a slave terminal among the other communication control devices configuring the network, changing the master terminal A master that determines whether to change one of its own device or the communication control device to which the data signal is transmitted to a master terminal so that a master change signal for requesting the data is generated by the transmission / reception unit The change determination unit and, when set as a master terminal, transmitted from another communication control device serving as a slave terminal. Receiving the master change request signal by the transmission / reception unit, cancels the setting as a master terminal and causes another communication control device to be set next to the master terminal to recognize that the setting of the master terminal is to be performed. A master change notification signal for controlling the generation of the master terminal by the transmission / reception unit, and when the slave terminal is set, the master change determination unit changes the master terminal. When it is determined that, after generating the master change request signal in the transmitting and receiving unit, transmits the master change request signal to another communication control device that is currently set to the master terminal, and, as a master terminal When set, when the master change request signal is transmitted from another communication control device serving as a slave terminal, the master control unit After unset as a master terminal, then the communication control unit and transmits the master change notification signal to the other communication control apparatus is set to the master terminal. 10. The master change determination unit, wherein a first data transfer time required when transmitting the data signal to the destination communication control device via a communication control device currently set as a master terminal is set. Calculating the second data transfer time from when the generation of the master change request signal is started to when the data signal is transmitted to the destination communication control device, and
10. The communication control device according to claim 9, wherein when the data transfer time is shorter than the first data transfer time, it is determined that the change of the master terminal is performed. 11. A terminal identification information storage unit for storing terminal identification information for identifying an individual communication control device, and a terminal of another communication control device set as a slave terminal when the network is constructed. A slave information storage unit that stores slave identification information that is identification information, and master identification information that stores master identification information that is terminal identification information of another communication control device set as a master terminal when the network is established. And when the master terminal is changed, the slave identification information in the slave information storage unit and the master identification information in the master identification information storage unit are deleted, and the slave information storage unit and the master identification are deleted. After the information storage is reset,
10. The apparatus according to claim 9, wherein the apparatus is in a standby state.
0. The communication control device according to 0. 12. The master change communication from a communication control device set as a master terminal in the network, wherein the master change communication is set as a slave terminal in the network and set as a master terminal after changing the master terminal. 12. The communication control device according to claim 11, wherein when a slave signal is received, the slave information storage unit and the master identification information storage unit are reset and set in a standby state, and then set to a master terminal. 13. When set in the master terminal, the transmission / reception unit generates a search signal for searching for another communication control device and recognizing that the communication terminal has been set in the master terminal. Transmit to the device, when receiving a reply signal to the search signal transmitted from another communication control device, the terminal identification information included in the reply signal as the slave identification information in the slave information storage unit By storing, the other communication control device set in the slave terminal is recognized, and when set in the slave terminal, a search signal transmitted from the other communication control device set in the master terminal is received. The terminal identification information included in the search signal is stored as the master identification information in the master identification information storage unit, so that the 12. The communication control apparatus according to claim 11, wherein the communication control apparatus recognizes the communication control apparatus, generates the return signal for the search signal in the transmission / reception unit, and transmits the response signal to another communication control apparatus set in the master terminal. Item 13. The communication control device according to item 12. 14. A network system constructed by a communication control device set as one master terminal and a communication control device set as a plurality of slave terminals, wherein the communication control device set as a slave terminal is: When transmitting a data signal to a communication control device set as another slave terminal, it is determined whether or not to change the setting of the master terminal based on the time required for transmission and reception of the data signal. When it is determined that the setting of the terminal needs to be changed, a master change for requesting that one of the two communication control devices set as slave terminals for transmission and reception be changed to the master terminal A network system for transmitting a request signal to a communication control device set as a master terminal. 15. The first data transmitted when two communication control devices, which are slave terminals for transmitting and receiving the data signal, transmit and receive the data signal via a communication control device set as a master terminal. After the transfer time is calculated, and after the change of the master terminal is started, after the two communication control devices that were the slave terminals that transmit and receive the data signal are set to the master terminal and the slave terminal, respectively,
A second data transfer time required for the two communication control devices to directly transmit and receive the data signal is calculated, and when the second data transfer time is shorter than the first data transfer time, the master change request The network system according to claim 14, wherein a signal is transmitted. 16. When a communication control device set as a master terminal receives the master change request signal,
Releases the setting of the master terminal of the own device, and transmits a master change notification signal for recognizing that the device is set as the master terminal to the communication control device set to the next master terminal. The network system according to claim 14 or claim 15, wherein 17. When a network is first constructed, a communication control device set to be a master terminal
17. A search signal for searching for another communication control device that is powered on and in a standby state is transmitted, and the other communication control device that has received the search signal is set as a slave terminal. The network system according to 1. 18. When reconfiguring the network by changing a communication control device serving as a master terminal, first, all communication control devices forming the network are set to a standby state, and then the master change notification signal is transmitted. A search signal for searching for another communication control device in a standby state is transmitted from the communication control device that has been received and newly set to be the master terminal, and another communication control device that has received the search signal 18. The network system according to claim 17, wherein is set as a slave terminal.