JP2002271342A - Radio communication network system, radio connection method and program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To maintain the relation of a network even if connection with a master unit is interrupted temporarily due to movement of a slave unit by recovering connection with that slave unit automatically. SOLUTION: The master unit monitors the received signal level from each of a plurality of slave units and forces each slave unit to monitor the received signal level from other slave unit (step A01). At a point of time when the received level from a part of slave units drops below a predetermined reference level (step A02), the master unit selects can other slave unit maintaining a received level from that slave unit at the reference level or above (steps A03-A05), and switching is made between the selected slave unit and the master unit (step A06).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to, for example, Bluet.
The present invention relates to a wireless communication network system, a wireless connection method, and a program suitable for a home wireless LAN system such as Bluetooth (hereinafter referred to as “Bluetooth”).

[0002]

2. Description of the Related Art Recently, a wide range of short-range wireless communication network systems applying the Bluetooth technology, which defines the IEEE 802.11 standard specifications as a basic specification, have been considered irrespective of whether they are inside a home or office. , And some have been commercialized.

[0003] However, such as that formed by one master device and a plurality of slave devices like Bluetooth,
In a wireless communication network system called a piconet, even if the propagation condition of radio waves is good at the time of network formation, if a slave device moves to a position where radio waves are cut off with respect to the master device during operation, the slave device Is disconnected from the network.

FIGS. 8 and 9 exemplify the operation status of such a network. At the beginning of operation, as shown in FIG. 8, one master unit M and first to third slave units S
1 to S3 are connected respectively.

At this time, although there is an obstacle O near the first slave unit S1, the master unit M is not located on the straight line between the master unit M and the first slave unit S1. And the connection with the first slave unit S1 is secured.

When the first slave unit S1 moves, as shown in FIG.
When the connection with the first slave unit S1 is disconnected, the master unit M can maintain the connection with the second and third slave units S2 and S3, but the first slave unit S1 can be connected again. Unless it moves to the position, the connection with the first slave unit S1 cannot be restored.

Accordingly, the first slave unit S1 cannot participate in this network until it moves to a position where it can be connected to the master unit M again.

[0008]

As described above, in the method of forming a piconet of Bluetooth, even if a plurality of slave units are connected to one master unit at the beginning of the formation of the network, the slave unit is connected to the master unit. If the slave unit moves and the radio wave cannot reach the master unit, the slave unit is disconnected from the master unit and cannot join the network.

[0009] Then, once the connection with the master unit is disconnected, there is a problem that the slave unit cannot be connected to the network until it moves to a position where radio waves can reach the master unit again. .

[0010] The present invention has been made in view of the above-described circumstances, and has as its object the object of the present invention even when the connection with the master machine is temporarily disconnected due to the movement of the slave machine or the like. It is an object of the present invention to provide a wireless communication network system, a wireless connection method, and a program that can restore a connection with the slave device and maintain a network relationship.

[0011]

According to the first aspect of the present invention,
In a wireless communication network system formed by one master unit and a plurality of slave units, the master unit monitors the reception level from each of the plurality of slave units, and each of the slave units also monitors other slave units. The master unit monitors the reception level from the slave unit, and when the reception level from a part of the slave unit falls below a predetermined reference value, the master unit determines that the reception level from the slave unit is higher than the reference value. Is selected, and master / slave switching is performed between the selected slave device and the master device.

With such a system configuration, not only the master unit but also each slave unit monitors the reception level of each other, and maintains the connection with the slave unit whose connection has been interrupted. Since the slave unit is automatically switched as a new master unit, the network connection relationship can be immediately restored even when the connection between the master unit and a part of the slave unit is disconnected.

According to a second aspect of the present invention, in a wireless communication network system formed by one master unit and a plurality of slave units, the master unit always recognizes a connection state with the plurality of slave units. In addition, when the connection with a part of the slave unit is cut off, the master unit requests the other slave unit to connect with the slave unit, and in response to this request, the slave unit whose connection has been cut off. Master / slave switching is performed between the slave unit and the master unit that have secured the connection.

With such a system configuration, the master unit that monitors the connection status with each slave unit is:
When the connection with a part of the slave unit is cut off, another slave unit that can be connected to the slave unit is found and automatically switched as a new master unit. The network connection relationship can be restored even when the connection is disconnected.

According to a third aspect of the present invention, there is provided a wireless connection method in a wireless communication network system formed by one master unit and a plurality of slave units, wherein the master unit is connected to each of the plurality of slave units. While monitoring the reception level, each of the slave units also monitors the reception level from another slave unit, and when the reception level from a part of the slave units falls below a predetermined reference value, the master unit sets the slave unit to the slave unit. Another slave device whose reception level from the device is equal to or higher than the reference value is selected, and master / slave switching is performed between the selected slave device and the master device.

According to this method, not only the master unit but also each slave unit monitors the reception level of each other, and the other slave units maintaining the connection with the slave unit whose connection has been interrupted. Since the device is automatically switched as a new master device, the network connection relationship can be immediately restored even when the connection between the master device and a part of the slave device is disconnected.

According to a fourth aspect of the present invention, there is provided a wireless connection method in a wireless communication network system formed by one master unit and a plurality of slave units, wherein the master unit is connected to a plurality of slave units. Always recognize the status, and when the connection with some of the slave units is cut off, the master unit will
A request is made to another slave unit to connect to the slave unit, and in response to this request, the master / unit is disconnected between the slave unit whose connection has been disconnected and the slave unit that has secured the connection.
It is characterized in that the slave is switched.

According to this method, the master unit monitoring the connection state between the slave units can be connected to the slave unit when the connection to a part of the slave unit is disconnected. Is found and automatically switched as a new master unit, so that the network connection relationship can be restored even when the connection between a part of the slave units and the master unit is disconnected.

According to a fifth aspect of the present invention, there is provided a program executed by a computer having a built-in master unit that forms a wireless communication network system with a plurality of slave units. A monitoring step of detecting a reception level, a monitor requesting step of requesting each slave unit to monitor a reception level from another slave unit, and a reception level from a part of the slave unit in the monitoring step. When the reception level from the slave unit is lower than the predetermined reference value, a selection step of selecting another slave unit whose reception level from the slave unit is equal to or higher than the reference value, and between the slave unit selected in the selection step. And causing the computer to execute an exchange step of switching between master and slave.

With such a program content, not only the master unit but also each slave unit can monitor the reception level of each other, and maintain the connection with the slave unit whose connection has been interrupted. Since the slave unit is automatically switched as a new master unit, the network connection relationship can be immediately restored even when the connection between the master unit and a part of the slave unit is disconnected.

According to a sixth aspect of the present invention, there is provided a program executed by a computer having a built-in master unit forming a wireless communication network system with a plurality of slave units. A recognition step of constantly recognizing the connection state, and a request step of requesting another slave machine to connect to the slave machine at the time when it is recognized that the connection with a part of the slave machine has been disconnected in the recognition process, A response receiving step of receiving a response sent from the slave unit whose connection has been disconnected and the slave unit having secured the connection in response to the request in the requesting step, and a slave unit sending a response in the response receiving step And a switching step of performing a master / slave switching between the two.

With such a program content, the master unit monitoring the connection status with each slave unit can be connected to the slave unit when the connection with a part of the slave unit is cut off. Since another slave unit is found and automatically switched as a new master unit, the network connection relationship can be restored even when the connection between the master unit and a part of the slave unit is disconnected.

[0023]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is applied to a wireless communication network system using Bluetooth technology will be described below with reference to the drawings.

The configuration of the master unit and the slave units of the entire network system is the same as that shown in FIG.
That is, three slave units S for one master unit M
1 to 3 are connected to form a piconet, the same devices are denoted by the same reference numerals, and illustration and description thereof are omitted.

FIG. 1 shows the configuration of a Bluetooth communication circuit provided commonly to the master unit M and the first to third slave units S1 to S3.
1, an RF unit 12, a baseband unit 13, and a link control unit 14.

The RF section 12 modulates the packet data to be transmitted received from the baseband section 13 into a radio frequency signal in the 2.45 GHz band on the transmitting side, and causes the antenna 11 to transmit and output the radio frequency signal.

On the receiving side of the RF unit 12, the transmitted packet data is received by the antenna 47, amplified, demodulated and output to the baseband unit 13, and the reception level contained in the packet data is also received. RSS that represents
I (Received Signal Strength)
h Indicator: RSSI signal
RSSI of the link control unit 14 detected by the I detection unit 12a
Output to the monitoring unit 14a.

The baseband unit 13 creates packet data according to a predetermined format from information to be transmitted on the transmitting side and outputs the packet data to the RF unit 12, while the receiving side converts the packet data demodulated by the RF unit 12 into packet data. By performing an error correction process or the like, the received information is extracted and output to the link control unit 14.

The link control unit 14 performs link control and management at the time of network connection in this circuit. In particular, the RSSI monitoring unit 14a extracts signals from signals received from other devices as shown in FIG. RSSI to RSSI
By updating and storing the information in the SI table T, it is possible to grasp the connection state between the respective devices.

FIG. 2 shows the structure of the RSSI table T stored in the RSSI monitoring section 14a. In particular, FIG. 2 shows the contents of the RSSI table T of the master unit M.

As shown in the figure, the RSSI table T stores RSSI values received from all devices connected to the network, ie, the master device M and each of the slave devices S1 to S3, based on ID information added to the header of the packet data. Therefore, only the RSSI value corresponding to the own device is blank.

Next, the operation of the above embodiment will be described.

FIG. 3 mainly shows the contents of processing executed by the link control unit 14 of the master unit M. At the beginning of the processing, the RSSI signals of the slave units S1 to S3 are monitored at predetermined intervals to check the RSSI monitoring unit. After repeatedly storing the RSSI table 14a of step 14a (step A01), it is determined whether or not there is an RSSI value lower than a preset threshold (step A02). Thus, it is determined whether or not the connection with each of the slave units S1 to S3 is maintained.

At this time, each of the slave units S1 to S3
It is also assumed that the RSSI values obtained from the master unit M and other slave units except the own unit are similarly updated and stored in the RSSI table T of the RSSI monitoring unit 14a.

FIG. 4 (1) shows each R from the first slave unit S1 and the second slave unit S2 grasped by the master unit M.
9 illustrates a time-series change of the SSI value.

As shown in FIG. 9, when the first slave unit S1 moves from the state shown in FIG. 8, an obstacle O is positioned between the master unit M and the first slave unit S1. ,
RS from the first slave unit S1 obtained by the master unit M
It is assumed that only the SI value sequentially decreases.

At a point in time after the timing t1 shown in FIG. 4A, the RSSI value from the first slave unit S1 falls below the threshold value, and the master unit M judges this at step A02 at this point. Then, one of the second slave unit S2 and the third slave unit S3, for example, the second slave unit S2, which still maintains a good connection relationship,
Is selected (step A03).

Next, the master unit M makes this selection for the selected second slave unit S2 based on whether or not the RSSI value from the disconnected first slave unit S1 is equal to or greater than a threshold value. The second slave machine S2 that has been
It is determined whether or not a good connection state with the slave device S1 is maintained (step A04).

FIG. 4 (2) exemplifies a time-series change of each RSSI value from the master unit M and the first slave unit S1 grasped by the second slave unit S2.

When the first slave unit S1 moves from the state shown in FIG. 8 as shown in FIG. 9, the obstacle O is located between the master unit M and the first slave unit S1. However, the RSSI value of the second slave device S2 from the first slave device S1 has not decreased, and
It can be seen that the slave device S2 still maintains a good connection state with the first slave device S1.

Therefore, in step A04, the second
Assuming that the RSSI value from the first slave device S1 received by the slave device S2 of
A master / slave switch request is sent to the second slave unit S2 by the link control unit 14 of the master unit M,
The roles of the master unit and the slave unit in the piconet are switched (step A06).

In step A04, when the selected slave unit determines that the RSSI value obtained from the slave unit disconnected from the master unit M is lower than the threshold value, the same as the master unit M is performed. Assuming that the selected slave unit also has deteriorated with the slave unit,
Next, it is determined whether there is any other slave device that can be selected as a master device candidate (step A05).

Here, if it is determined that there is, the above-mentioned step A03 is selected again to select the slave unit.
Returning to the processing from, if it is determined that the piconet is not maintained any more, it is determined that it is difficult to maintain the piconet any more, and the processing is terminated and the network is dissolved.

FIG. 5 illustrates the communication timing of the packet data transmitted and received between the master unit M and each of the slave units S1 and S2 as described above.

Normally, as shown in FIG. 5A, the master unit M transmits a transmission request after designating the ID of the destination slave unit in the packet header in a certain slot, and transmits the transmission request in the immediately succeeding slot. When the packet data is transmitted as requested from the slave device, it is received, and at the same time, the reception level is detected from the RSSI value from the slave device.

At the same time, as shown in FIGS. 5 (2) and 5 (3), each of the slave units S1 and S2 receives a transmission request from the master unit M and specifies its own ID in its packet header. If it is recognized that there is, a response is made to the master unit M in the slot immediately after that.

On the other hand, when each of the slave units S1 and S2 receives the transmission request from the master unit M and specifies the ID of the other unit in its packet header, the slave unit S1 or S2 transmits the RS of the signal.
The SI value is detected as the reception level of the master unit M, and a response transmitted from the other unit whose ID is designated to the master unit M is received in the slot immediately after the SI value, and the RSS is received.
The reception level of the other device is detected based on the I value.

FIG. 6 shows the result of performing a master / slave switch between the master unit M and the second slave unit S2 from the network connection state of FIG. 9 according to the processing contents shown in FIG. Things.

As shown in the figure, the master / slave switching is automatically performed between the second slave unit S2 and the master unit M, which maintain a good connection state with the first slave unit S1, so that Even if one slave unit S1 moves to a position where communication is hindered by the presence of the obstacle O for the original master unit M, the second slave unit S2 is set as a new master unit M ', and By using the master unit M as the new fourth slave unit S4, the operation of the piconet can be maintained without the influence of the obstacle O.

As described above, not only the master unit M but also the slave units S1 to S3 monitor the reception level of each other, and maintain the connection with the slave unit whose connection has been interrupted. Since the slave unit is automatically switched as a new master unit, the network connection relationship can be immediately restored even when the connection between the master unit and a part of the slave unit is disconnected.

In the above embodiment, the reception level of each of the slave units S1 to S3 is monitored in addition to the master unit M during network communication, and the connection with the slave unit whose connection has been interrupted is maintained. The other slave units are automatically switched as a new master unit.However, such a method is not adopted, and the master unit is used during normal network communication in which connection with each slave unit is secured. The monitoring may not be performed by the slave units other than M.

FIG. 7 shows another processing content mainly executed by the link control unit 14 of the master unit M according to the embodiment of the present invention. After establishing synchronization with the devices S1 to S3 and detecting the RSSI value at that time (step B0
1) By repeatedly executing a process of determining whether there is a disconnected slave unit based on whether there is an RSSI value lower than a preset threshold value (step B02), It is determined whether the connection with each of the slave units S1 to S3 is maintained.

When the first slave unit S1 moves from the state shown in FIG. 8 as shown in FIG. 9, for example, an obstacle is placed between the master unit M and the first slave unit S1. It is assumed that O is located and only the RSSI value from the first slave unit S1 obtained by the master unit M sequentially decreases.

In this case, when the RSSI value obtained from the first slave unit S1 obtained by the master unit M sequentially decreases and falls below the threshold value, the master unit M determines that there is a slave unit disconnected in step B02. Judgment is made, and next, a request is made to each of the other slave units S2 and S3 for connection with the disconnected slave unit S1 (step B03).

Thereafter, it is determined from each of the slave units S2 and S3 whether or not there is at least one other slave unit that can be connected to the first slave unit S1 disconnected from the master unit M. Judgment is made based on the response (step B0
4).

Here, if none of the slave units S2 and S3 can establish a connection with the slave unit S1, there is no slave unit S1 found, and it is no longer possible to maintain this piconet. When it is determined that it is difficult, this process is completed and the network is dissolved.

In step B04, at least one aircraft
For example, when a response is received from the slave unit S2 indicating that the connection with the slave unit S1 has been established, the master unit M
Automatically switches master / slave with the slave unit S2 (step B05), and thereafter disconnects the second slave unit S2 as a new master unit M 'and the master unit M'. After a new piconet is formed by reconnecting with the first slave unit S1 that has been established (step B06), the process from step B01 is continued by the new master unit M '.

As described above, according to the processing contents shown in FIG. 7, the master unit M is changed from the network connection state shown in FIG.
By performing a master / slave switch between and the second slave unit S2, a connection state as shown in FIG. 6 can be obtained.

In this case, master / slave switching is automatically performed between the second slave unit S2 connectable to the first slave unit S1 and the master unit M, and the first slave unit S1
1 and the old second slave unit S2 which is the new master unit M '
And the first slave unit S1
Moves to a position where communication is hindered by the obstacle O for the original master unit M, the second slave unit S2 is set as a new master unit M ', and the original master unit M is set as a new master unit M'. As the fourth slave unit S4, the operation of the piconet can be maintained while eliminating the influence of the obstacle O.

As described above, the master unit M monitoring the connection state between the slave units S1 to S3 can be connected to the slave unit S1 when the connection to the slave unit S1 is cut off, for example. Since another slave unit S2 is found and the master / slave is automatically switched as a new master unit M ', the network connection relationship is automatically established even when the connection between the slave unit S1 and the master unit M is disconnected. You can recover.

In addition, in the processing contents shown in FIG.
Compared to the processing described in FIG. 3, the piconet is established, and there is no need for each slave unit to detect the reception level of another device in a normal time difference state where there is no disconnected slave unit. Therefore, the operation power of each slave unit is not wasted, and this is particularly suitable when a device whose power amount is limited is used as a slave unit.

The operation described in the above embodiment is
Each of the master unit M and the slave units S1 to S3 is stored in the form of an operation program in the link control unit 14 and executed and processed.
May be fixedly recorded on the device, or may be installed on a device that has been downloaded via another recording medium or communication medium when the device is upgraded.

The present embodiment is an example in which the present invention is applied to a piconet as a wireless communication network system using the Bluetooth technology.
The present invention is not limited to this, but includes a wireless communication network system connected between one master unit and a plurality of slave units, a device handled by the system, a program installed in the device, and the like. It goes without saying that any form is applicable.

In addition, the present invention is not limited to the above-described embodiment, and can be variously modified and implemented without departing from the gist thereof.

Furthermore, the above embodiments include inventions at various stages, and various inventions can be extracted by appropriately combining a plurality of disclosed constituent features. For example, even if some components are deleted from all the components shown in the embodiments, at least one of the problems described in the column of the problem to be solved by the invention can be solved and the effects described in the column of the effect of the invention can be solved. In a case where at least one of the effects described above is obtained, a configuration in which this component is deleted can be extracted as an invention.

[0066]

According to the first aspect of the present invention, not only the master unit but also the slave units monitor the reception level of each other and maintain the connection with the slave unit whose connection has been interrupted. Since another slave unit is automatically switched as a new master unit, the network connection relationship can be immediately restored even when the connection between the master unit and a part of the slave unit is disconnected.

According to the second aspect of the present invention, the master unit monitoring the connection state with each slave unit is connected to the slave unit when the connection with a part of the slave unit is disconnected. Since another possible slave unit is found and automatically switched as a new master unit, the network connection relationship can be restored even when the connection between a part of the slave units and the master unit is disconnected.

According to the third aspect of the present invention, not only the master unit but also each slave unit monitors each other's reception level to maintain the connection with the slave unit whose connection has been interrupted. Is automatically switched as a new master device, so that even if the connection between a part of the slave device and the master device is disconnected, the network connection relationship can be restored immediately.

According to the fourth aspect of the present invention, the master unit monitoring the connection state with each slave unit allows
When the connection with a part of the slave unit is cut off, another slave unit that can be connected to the slave unit is found and automatically switched as a new master unit. The network connection relationship can be restored even when the connection with the network is disconnected.

According to the fifth aspect of the present invention, not only the master unit but also each slave unit monitors the reception level of each other to maintain the connection with the slave unit whose connection has been interrupted. Is automatically switched as a new master device, so that even if the connection between a part of the slave device and the master device is disconnected, the network connection relationship can be restored immediately.

According to the sixth aspect of the present invention, the master unit monitoring the connection state with each slave unit allows
When the connection with a part of the slave unit is cut off, another slave unit that can be connected to the slave unit is found and automatically switched as a new master unit. The network connection relationship can be restored even when the connection with the network is disconnected.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a Bluetooth communication circuit common to all devices according to an embodiment of the present invention.

FIG. 2 is a view exemplifying a configuration of an RSSI table stored in an RSSI monitor of FIG. 1;

FIG. 3 is an exemplary flowchart showing processing contents mainly executed by a link control unit of the master machine according to the embodiment;

FIG. 4 is a diagram showing a reception level detection state of another device in the master device and the slave device according to the embodiment;

FIG. 5 is a diagram showing detection timings of reception levels of other devices in the master device and the slave device according to the embodiment.

FIG. 6 is an exemplary view showing a network connection state of the piconet after recovery according to the embodiment;

FIG. 7 is an exemplary flowchart showing another processing content mainly executed by the link control unit of the master machine according to the embodiment;

FIG. 8 is a diagram showing a network connection state of a general piconet.

FIG. 9 is a view showing a network connection state of a general piconet.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 ... Antenna 12 ... RF part 12a ... RSSI detection part 13 ... Base band part 14 ... Link control part 14a ... RSSI monitoring part M, M '... Master machine O ... Obstacle S1-S4 ... Slave machine T ... RSSI table

Claims (6)

[Claims] In a wireless communication network system formed by one master unit and a plurality of slave units, the master unit monitors reception levels from the plurality of slave units, and each of the slave units. The master also monitors the reception level from another slave unit, and when the reception level from a part of the slave unit falls below a predetermined reference value, the master unit determines that the reception level from that slave unit is higher than the reference value. A wireless communication network system comprising: selecting another maintained slave device; and switching between the selected slave device and the master device for master / slave. 2. In a wireless communication network system formed by one master device and a plurality of slave devices, the master device always recognizes a connection state with the plurality of slave devices, and When the connection with a part is disconnected, the master unit requests the other slave units to connect to the slave unit, and in response to this request, the slave unit that has established the connection with the disconnected slave unit. A wireless communication network system for performing master / slave switching between a device and a master device. 3. A wireless connection method in a wireless communication network system formed by one master unit and a plurality of slave units, wherein the master unit monitors reception levels from each of the plurality of slave units. Each of the slave units also monitors the reception level from another slave unit, and when the reception level from a part of the slave units falls below a predetermined reference value, the master unit determines whether the reception level from the slave unit is lower. A wireless connection method comprising selecting another slave device maintaining the reference value or more, and performing switching between master / slave between the selected slave device and the master device. 4. A wireless connection method in a wireless communication network system comprising one master unit and a plurality of slave units, wherein the master unit always recognizes a connection state with the plurality of slave units. When the connection to a part of the slave unit is disconnected, the master unit requests the other slave units to connect to the slave unit, and in response to this request, the master unit A wireless connection method characterized by performing a master / slave switch between a slave unit and a master unit that have secured a connection. 5. A monitor for detecting a reception level from each of a plurality of slave units, the program being executed by a computer having a built-in master unit forming a wireless communication network system with the plurality of slave units. A monitoring step for requesting each of the slave units to monitor a reception level from another slave unit; and a reference value in which the reception level from a part of the slave unit in the monitoring step is determined in advance. A selection step for selecting another slave unit whose reception level from the slave unit is equal to or higher than the reference value if the reception level falls below the reference value; and a master / slave switching between the slave unit selected in the selection step. And a replacement step of causing a computer to execute the replacement step. 6. A program executed by a computer having a built-in master unit that forms a wireless communication network system with a plurality of slave units, and constantly recognizes a connection state with the plurality of slave units. A recognition process, a request process for requesting another slave device to connect to the slave device when it is recognized that the connection with a part of the slave device has been disconnected in the recognition process, and a request in the request process. A response receiving step of receiving a response sent from the slave unit whose connection has been disconnected and the slave unit having secured the connection, and a master / slave unit transmitting a response in the response receiving step. A program for causing a computer to execute an exchange step of switching a slave.