KR100650269B1 - Method of generating a bluetooth scatternet automatically - Google Patents

Abstract

An automatic Bluetooth Scatternet generation method is provided to designate more than one target apparatus among apparatuses existing in a Bluetooth network, while each apparatus searches neighboring apparatuses connectable to the target apparatuses with the shortest hop distance, so as to automatically form a Scatternet capable of performing communication with the target apparatuses. More than one apparatus receives inquiry messages transmitted from neighboring apparatuses(400), and decides whether address information of the neighboring apparatuses, routing information of target apparatuses, is already stored(402). If not, and if a connection request to the predetermined target apparatuses is inputted(414), the apparatuses decide whether hop distance information between the apparatuses and the target apparatuses is 0(416). If not, the apparatuses demand connections with the target apparatuses to the neighboring apparatuses(418). The connections are formed between the target apparatuses and the neighboring apparatuses(420).

Description

Method of generating a bluetooth scatternet automatically}

1 is a diagram illustrating a process of forming a communication connection in a Bluetooth communication network;

2 is a diagram illustrating an inquiry between devices for automatic generation of a Bluetooth scatternet according to the present invention;

3 is a diagram illustrating a routing table for a target device of each device illustrated in FIG. 2;

4 is a flowchart illustrating a method for automatically generating a Bluetooth scatternet according to the present invention.

The present invention relates to a method for automatically generating a Bluetooth scatternet.

Bluetooth is a short-range wireless communication technology standard developed to enable free wireless communication between various devices in a relatively small area (10-100m) at low cost and low power consumption.

In 1994, Ericsson Mobile Communication Group began researching low-power and low-cost radio interfaces between mobile phones and peripherals.In February 1998, Ericsson, Nokia, IBM, Toshiba, The Bluetooth Special Interest Group (SIG), composed of Intel, was launched, and the SIG released the version 1.0 Bluetooth specification in August 1999. The official international standards body is the IEEE 802.15 workgroup, which sets international standards based on the Bluetooth specification. We work closely with the SIG for this purpose.

Bluetooth can be installed in all information devices used in homes and offices, and it is possible to configure a wireless network between them and to interwork with any wired / wireless network. Therefore, when the wireless network using Bluetooth is completed, data exchange between all information devices, especially laptops, PDAs, and mobile phones, is free. When the Internet bridge is configured using Bluetooth, it reaches the desktop computer through optical cable, ADSL, modem, etc. Internet information can be reached in the user's hand.

In other words, by using Bluetooth, anyone can reach the ultimate goal of wireless communication anytime, anywhere, anyone, any type of information exchange.

Bluetooth forms a link in a master / slave manner. In other words, when two devices are connected, one device plays the role of master and the other device plays the role of slave. One master can connect up to seven slaves to form a network. This is called a piconet. When multiple piconets are gathered, a hierarchical and large network can be formed. This is called a scatternet.

Piconet defined in Bluetooth is a network formed by connecting one master device and several slave devices with a distance of 1 hop.

Scatternets are formed by making communication connections between piconets when it is necessary to form a relatively large network by supplementing the short communication distance of Bluetooth, and enable communication between devices included in different piconets.

However, in order to form a scatternet, it is troublesome to designate between two devices to be connected through arbitrary user intervention so that two devices existing on different piconets can communicate with each other.

Accordingly, an object of the present invention is to provide a method for automatically generating a scatternet of Bluetooth, in which a scatternet is automatically generated in a Bluetooth communication network to allow communication between devices.

In order to achieve the above object, according to the present invention, a method for automatically generating a Bluetooth scatternet according to the present invention searches for neighboring devices to which Bluetooth devices can be connected to a predetermined target device in the shortest hop distance, and stores address information of the found neighboring devices. Laying step; And requesting a connection from a neighboring device storing the address information to form a connection with the target device when a predetermined Bluetooth device intends to communicate with the target device.

The neighbor device search of each of the Bluetooth devices may include: transmitting, by the target device, hop distance information with itself to the neighboring devices as 1; Starting from the transmission of the hop distance information of the target device, each Bluetooth device transmits the hop distance information with the target device via itself to the peripheral devices and transmits the hop distance information of the smallest value among the peripheral devices. Searching for a device with a neighboring device;

The neighbor device search of each of the Bluetooth devices may include searching for neighboring devices that can be connected to the respective target devices in the shortest hop distance when there are a plurality of predetermined target devices.

Meanwhile, the hop distance information transmission of the Bluetooth devices is transmitted through the inquiry message when the Bluetooth devices are found to their neighbor devices, and the hop distance information transmitted by the Bluetooth devices to the peripheral device is the Bluetooth device. Is 1 plus hop distance information received from a new device discovered by its neighboring device.

In the method for automatically generating a Bluetooth scatternet according to the present invention, when the connection distance between the target device and the target device is not 0, the connection request is made to the neighboring device and the connection with the corresponding device is requested. Forming; And forming a connection with the target device by sequentially forming a connection with the neighboring device until the hop distance information with the target device is 0 in the neighboring device that is requested to be connected.

Hereinafter, with reference to the accompanying drawings will be described the present invention in more detail. However, in describing the present invention, when it is determined that a detailed description of a related known function or configuration may unnecessarily obscure the subject matter of the present invention, a detailed description thereof will be omitted.

1 is a diagram illustrating a process of forming a communication connection in a Bluetooth communication network.

The communication connection between two devices in Bluetooth communication is formed by Inquiry and Page. If the device attempting to establish a communication connection knows no information about the devices in the vicinity, it must perform both an inquiry and a page.

However, if you know about the external device, you can form a link by only performing a page without performing an inquiry.

Inquiries and inquiries are performed as follows. The device performing the inquiries broadcasts an inquiry message to the surrounding devices and repeats waiting for an inquiry response. Once the device being scanned for an inquiries receives this message, it will spend 0 to 640 ms and once again receive an inquiries message, it will then receive an inquiries response, that is, information about its frequency hopping synchronization (FHS). ) Sends the packet to the device performing the inquiry.

The reason for the 0 ~ 640ms time delay is that the inquiries are performed using an Inquiry Access Code (IAC) so that all devices can hear them, so if multiple devices are in an inquiries scan state, the inquiries This is because the response messages collide by sending an inquiry response immediately after receiving the message.

When the inquiries / inquiries are performed as described above, the device that has performed the inquiries knows information about the device that has sent the inquiries response.

Page / page scans are performed similarly to inquiries / inquiries.

If a device wants to establish a communication connection with a particular device, the device enters page mode and sends a page message to the external device. When the status of the external device is a page scan and this page message is received, the Bluetooth hopping sequence and the clock information are exchanged between the two devices to synchronize the frequency hopping sequence and establish a communication connection.

The difference between inquiries and pages is that inquiries are used to learn information about peripherals, so all devices can send inquiries responses, Pages send messages to specific devices and respond immediately without time delays when performing page scans, so the page process takes much less time than the enquiry process.

FIG. 2 is a diagram illustrating an inquiry between devices for automatically generating a Bluetooth scatternet according to the present invention. In the present invention, a Bluetooth scatternet is automatically generated in an Ad-Hoc environment using a Bluetooth inquiry process. To help.

Referring to FIG. 2, a target device is designated before the enquiry process is performed in an ad hoc network environment in which a plurality of Bluetooth devices exist. Herein, a case where the device A is the target device will be described as a representative example, and the hop distance HOP_Self from the target device is preset to 0 hops.

Each Bluetooth device in the ad hoc network environment has a routing table for establishing a connection with the target device.

The routing table includes address information (Target_ADDR) of the target device, address information (Neighbor_ADDR) of a neighboring device that can be connected with the shortest hop distance from the target device, and hop distance information (HOP_Self) between itself and the target device through the neighboring device. Each Bluetooth device updates address information of the neighboring device having the smallest hop distance from the target device in the routing table through an enquiry process.

As shown in the figure, the inquiries between the Bluetooth devices according to the present invention broadcast the inquiry message to the devices in which the device A designated as the target device exists in its communication area, and the device B in the same communication area. Device C begins by receiving an inquiry message of device A while performing an inquiry scan (1).

Inquiry message sent by device A includes the address information of the target device (in this case, its own address information), its own address information for transmitting the inquiry message, and the hop distance information (HOP_Self) with the target device plus 1; It is included as hop distance information (HOP_Inq) transmitted to other devices.

Each device B and device C transmit the address information of the device A as the address information of the neighboring device and the hop distance information (HOP_Self) in the routing table for the target device through the inquiry message information transmitted by the device A. The hop distance information (HOP_Inq) included in the message information is stored.

Each B device and C device adds 1 to the hop distance information (HOP_Self) stored in the routing table to generate hop distance information (HOP_Inq) to be transmitted to another device, and generates the generated hop distance information (HOP_Inq) and its own. The address information and the address information of the target device are included together to generate an inquiry message, and then broadcast to devices existing in the communication area.

In the drawing, first, device B performs an inquiry and broadcasts an inquiry message to device D, device C, and device A present in its communication area (2), device D, device C, and The device A receives an inquiry message transmitted from the device B while performing an inquiry scan, and checks whether the routing information of the target device is already stored in its routing table through the received inquiry message.

Accordingly, if the routing information to the target device already exists, the hop distance information included in the inquiry message currently receiving hop distance information (HOP_Self) between itself and the target device through the neighbor device stored in the routing table. If the hop distance information (HOP_Inq) included in the currently received inquiry message is a smaller value, the address information of the B device transmitting the current inquiry message as the address information of the neighbor device to the routing table is compared with (HOP_Inq). Stores the hop distance information (HOP_Inq) included in the inquiry message transmitted by the device B as the hop distance information (HOP_Self) from the target device, and updates routing information to the target device.

When the inquiry process of the device B is terminated, the inquiry process of the device C is performed, and the above process is performed in the devices receiving the inquiry message of the device C (③).

Meanwhile, referring to the case of device D, only the inquiry message transmitted by device B while being in the same communication area as device B is received. Accordingly, the address information of the device B is stored in the routing table for the device A, which is the target device, as the address information of the neighbor device, and the hop distance information (HOP_Inq) included in the inquiry message of the device B as the hop distance information (HOP_Self) with the target device. Save).

FIG. 3 is a diagram illustrating a routing table for target devices of respective devices existing on the network shown in FIG. 2.

Each device (device B, device C, device D) on the Bluetooth network performs an inquiry process as described with reference to FIG. 2 and the neighbor device having the smallest hop distance with device A designated as the target device. The address information and hop distance information HOP_Self between the target device and its own through the neighboring device are stored in its own routing table.

As shown in the drawing, device B and device C request a connection to device A and establish a communication connection while the neighboring device, which needs to perform a connection request to communicate with the target device, becomes a device A, which is a target device. Can be.

If a device is to be connected from device D to device A, the device B, which is stored as a neighbor device in its routing table, requests a connection with the target device, and device B connects with device D according to the connection request of device D. After establishing the connection, the device establishes a communication connection with the device A while requesting the connection to the device A which is its neighbor device and the target device.

Accordingly, the device D makes a communication connection with the device A located in the other communication area via the device B, that is, the scatternet is automatically formed and communication between the two devices located in the same communication area is possible.

Meanwhile, in the present invention, the case where there is only one device designated as the target device in the Bluetooth communication network will be described as an example. Each Bluetooth device existing on the network also has a routing table for one target device. As described.

However, a plurality of target devices may be designated, and accordingly, each Bluetooth device may have a routing table for each of the designated plurality of target devices. Each Bluetooth device routes address information of the neighboring device having the shortest hop distance to each of the plurality of target devices and hop distance information (HOP_Self) between itself and the target device through the neighboring device to the corresponding target device through inquiries. Save it to a table.

When each device receives a request for connection to a specific target device from a device that stores itself as a neighbor device, each device connects itself with the device requesting the connection. If the hop distance information (HOP_Self) between the target device and the target device is not 0, that is, the target device is not the target device, the neighboring device is designated as its neighbor device. Request the device to connect with the target device again.

Thus, the above process is sequentially performed until the connection with the device having the hop distance information HOP_Self is 0, so that the shortest distance communication network, that is, the scatternet, is automatically generated between two devices that are separated by one or more hops. .

4 is a flowchart illustrating a method for automatically generating a Bluetooth scatternet according to the present invention.

According to the present invention, one or more of the devices existing in the Bluetooth network are designated as the target device. Each device performs an inquiry scan and receives an inquiry message transmitted from peripheral devices (400).

If the received inquiry message exists, the address information of the target device included in the inquiry message is checked to see whether the address information of the neighbor device, which is routing information for the target device, is already stored (402).

As a result, if the neighbor device for the target device is already stored, the hop distance information (HOP_Self) between itself and the corresponding target device through the neighbor device and the hop distance information (HOP_Inq) included in the received inquiry message Compare 404.

When the neighboring device for the target device is not stored or the hop distance information (HOP_Inq) received is smaller than the hop distance information (HOP_Self) through the neighboring device, the current inquiry message is transmitted. The device is set as a neighbor device of the target device, and the address information of the device is stored (406).

In addition, the hop distance information (HOP_Inq) included in the received inquiry message is stored as its own hop distance information (HOP_Self) (408), and the hop distance information (HOP_Self) added to the newly stored hop distance information (HOP_Self) is transmitted to other devices. (HOP_Inq) is generated (410).

Thus, the generated hop distance information (HOP_Inq) is included in its inquiry message and transmitted to the peripheral devices (412), so that other devices may store neighbor devices to request connection in order to be connected to the target device in the shortest distance. To help.

When the connection request to the predetermined target device is input (414), if the hop distance information HOP_Self between itself and the corresponding target device is not 0 (416), that is, it is not determined whether the target device is not the corresponding target device. In operation 418, the neighbor device stored by matching the target device with the corresponding target device is requested.

In response to the request, a connection is first established with the neighboring device (420), and the neighboring device checks the hop distance information (HOP_Self) with the corresponding target device again as mentioned above, and if it is not the corresponding target device. Only the device designated as its neighbor device requests a connection with the corresponding target device.

Thus, the above process is sequentially performed until the connection with the device having the hop distance information HOP_Self is 0, and a scatternet capable of communicating with a target device at a distance of more than one hop is generated.

Although the present invention has been described in detail with reference to exemplary embodiments above, those skilled in the art to which the present invention pertains can make various modifications to the above-described embodiments without departing from the scope of the present invention. I will understand. Therefore, the scope of the present invention should not be limited to the described embodiments, but should be defined by the claims below and equivalents thereof.

According to the present invention, each device is the shortest hop distance from the target device so that a scatternet capable of designating one or more target devices among the devices present on the Bluetooth network and communicating with the target device can be automatically formed. Search for neighboring devices that can be connected. When there is a connection request to the target device, a request is made to connect to its neighbor device so that a communication network and a scatternet to the target device are automatically formed without user intervention.

Claims (6)

Searching for neighboring devices that can be connected to each of the Bluetooth devices in a shortest hop distance to a predetermined target device, and storing address information of the found neighboring devices; And Requesting a connection from a neighboring device storing the address information to form a connection with the target device when a predetermined Bluetooth device intends to communicate with the target device; . The method of claim 1, The neighbor device search of each Bluetooth device And searching for neighboring devices which are connectable to the respective target devices in the shortest hop distance, when there are a plurality of predetermined target devices. The method of claim 1, The neighbor device search of each Bluetooth device Transmitting, by the target device, hop distance information with itself to the neighboring devices as 1; And Starting from the transmission of the hop distance information of the target device, each Bluetooth device transmits hop distance information with the target device through itself to peripheral devices and transmits hop distance information of the smallest value among the peripheral devices. Searching for the neighboring device; Bluetooth scatternet automatic generation method comprising the. The method of claim 3, wherein The hop distance information transmission of the Bluetooth devices The Bluetooth device automatically generates a Bluetooth scatternet, characterized in that when the new device is found as a neighboring device via its own inquiry message. The method of claim 4, wherein The hop distance information that the Bluetooth devices transmit to the peripheral device is Method for automatically generating a Bluetooth scatternet characterized in that the Bluetooth device is a value of 1 plus the hop distance information received from a new device found in its neighboring device. The method of claim 1, The connection with the target device is formed, Requesting a connection to its neighboring device and forming a connection with the corresponding device when the hop distance information between the target device and the target device is not 0; And Forming a connection with the target device by sequentially forming a connection with the neighboring device until the hop distance information with the target device is 0 in the neighboring device that has received the connection; How to automatically create a scatternet.

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