KR100298981B1 - Local radio communication method by use of bluetooth - Google Patents

Abstract

In a short-range wireless communication method using Bluetooth, a predetermined packet allowing data transmission from a master Bluetooth module to at least one slave Bluetooth module is sequentially transmitted, and a preset data packet transmitted from a slave Bluetooth module is transmitted. After receiving and demodulating and providing the host to the host, the slave module receives a preset packet allowing data transmission from the master Bluetooth module, modulates the transmission data of the host, and provides the master module with the master module.

Description

Near field communication method using Bluetooth {LOCAL RADIO COMMUNICATION METHOD BY USE OF BLUETOOTH}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to short-range wireless communication, and more particularly, to a short-range wireless communication method that is preferably applied to a wireless interface between a computer using Bluetooth and its peripheral device.

In recent years, the wireless communications and computer industries have realized that low cost, low power wireless devices or wireless links are indeed possible. Such wireless communication provides a basis for the elimination of complicated connection cables between office devices and communication between devices, which emphasizes the compactness and portability, in accordance with recent development trends.

Various studies have been conducted on this, and a professional code, namely 'Bluetooth' has been defined at Ericsson. The goal of Bluetooth is to provide mobility and convenience services for business users due to the small, short-range radio. Bluetooth has defined technical characteristics that optimize the usage model of portable computers and communication devices. Bluetooth is specifically designed to provide low cost, robustness, efficiency, high capacity, especially voice and data networking.

Such Bluetooth is applicable to a computer system consisting of a personal computer, a keyboard, a mouse, a monitor, a printer, and the like.

An object of the present invention is to provide a short-range wireless communication method that is preferably applied to a wireless interface between a computer and its peripheral device using Bluetooth.

In order to achieve the above object, the present invention provides a short-range wireless communication method using Bluetooth, which sequentially transmits a predetermined packet allowing data transmission from a master Bluetooth module to at least one slave Bluetooth module, and wherein the slave Receiving and demodulating the preset data packet transmitted from the Bluetooth module on the side and providing the host to the host; receiving the preset packet allowing the data transmission from the master Bluetooth module in the slave module. And modulating the transmission data of the host to provide the master module with the Bluetooth module.

1 is a schematic diagram of a computer system,

2 is a schematic hardware block diagram of a Bluetooth module;

3 is a functional block diagram of a Bluetooth module;

4 is a transport packet format diagram according to an embodiment of the present invention;

5 is a flowchart of an inquiry operation according to a Bluetooth standard;

6 is a flowchart illustrating a connection operation according to a Bluetooth standard;

7 is an operation flowchart of a computer main body according to an embodiment of the present invention;

8 is an operation flowchart of a keyboard or a mouse according to an embodiment of the present invention.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the following description, specific details such as specific components are shown, which are provided to help a more general understanding of the present invention, and it is understood that these specific details may be changed or changed within the scope of the present invention. It is self-evident to those of ordinary knowledge in Esau.

1 is a schematic diagram of a computer system. Figure 1 (a) is a general computer system, Figure 1 (b) is a computer system according to an embodiment of the present invention. The computer system of the present invention is equipped with a wireless communication module, that is, a Bluetooth module, on the computer main body 10, the keyboard 12, and the mouse 14. Referring to FIG. 1B, a Bluetooth module is mounted on the computer main body 10 and the keyboard 12, and wireless communication is performed according to a Bluetooth standard.

2 is a schematic hardware block diagram of a Bluetooth module. The Bluetooth modules 20 and 25 shown in FIG. 2 are mounted to the computer body 10 and the keyboard 12, respectively. Each configuration is transmitted and received by the RF transmitter 24, 29 and the RF receiver 23, 28, and the RF transmitter 24, 29 and RF receiver 23, 28 to wirelessly transmit and receive data packets according to the Bluetooth standard. The baseband processor 22, 27 for modulating and demodulating the signal, and the controller 21, 26 for controlling the overall operation of the module.

3 is a functional block diagram of a Bluetooth module. The subject of communication is called a host 30, and a device that accepts its request and enables communication with other Bluetooth devices according to the Bluetooth standard is called a Bluetooth module 35. An interface called an HCI (Host Control Interface) is defined between the host 30 and the Bluetooth module 35, and a control command, a result thereof, and a user's transmission / reception data come and go by exchanging a packet corresponding thereto. The actual forwarding of HCI packets can be done with the popular RS232C, USB and standard PC interfaces.

Referring to FIG. 3, the host 30 includes other high layer drivers 31, a Bluetooth HCI driver 32, and a driver 33 such as a physical bus, that is, an RS323C, USB, and PC Card. The module 35 is provided with HCI firmware (hereinafter referred to as HCI) 36, a link manager firmware (hereinafter referred to as LM) 37 and a baseband controller 38. The transmission layer of the host controller is composed of a physical bus driver 33 and a physical bus firmware 34.

The HCI packet is divided into command, event, and data packet, and the command packet provides 60 types of commands for using various Bluetooth modules.

The Bluetooth system performs an inquiry process to find an address of a peripheral Bluetooth device before establishing a connection for communication. This is done by having the host initiate the inquiry procedure to the Bluetooth module using the HCI command. It is the baseband control unit and the wireless interface unit that perform the actual inquiry process and the result is reported to the host as an HCI event.

A Bluetooth device that is not performing an inquiry informs its own address as long as the operation state of the inquiry process of another Bluetooth device allows, and this is called an inquiry scan / response. Based on the address of the peripheral Bluetooth device collected during the inquiry process, select the address of the Bluetooth device to communicate with, establish a connection, and send and receive data. In addition, various HCI commands and addresses of Bluetooth modules can be used to find out information about the other Bluetooth device.

5 is a flowchart of an inquiry operation according to the Bluetooth standard. In the module that executes the inquiry process, the host starts to inquire a regular interval with a certain interval (50-1). This command causes the link manager to set a value in the register to control the baseband side, and start the inquiry process on the baseband side (50-2). The baseband, which initiates the inquiry process, repeatedly transmits an inquiry train composed of continuous transmission of inquiry packets for a predetermined time (50-3).

On the other hand, the transmission slot transmits an inquiry packet, but the reception slot waits for a response from another module. If a module performing an inquiry scan receives an inquiry packet in consecutive inquiry train intervals, the module generates a random number and remembers the frequency when the inquiry packet is received and then slips. Goes to the pf state. After that, the module wakes up from the sleep state after a random number of slots elapses and waits for a hopping frequency that has been triggered by the module. Receive Slots) transmits a Frequency Hopping Synchronous (FHS) packet in response to the inquiry (50-4, 5, 6).

After sending the FHS packet, the module adds offset 1 to its frequency hopping phase, generates a random number again, sleeps during the random period, wakes up, and adds an offset of 1 to the hopping frequency. Wait. When triggered again, the FHS packet is transmitted in response to the inquiry in its transmission slot (relative RX slot). It then generates a random number, adds offset 1, then sleeps, and repeats until this scan timed out.

The baseband side of the module that receives the FHS packet in the inquiry response informs the host that the response has been received with the value set in the internal register (50-7, 8, 9), and by setting this register, HCI informs the host of the result of the inquiry. Occurs (50-10, 11, 12).

Inquiry is executed when all modules, whether master or slave modules, have returned the time they need to inquire by their internal counters. In this case, however, the inquiry is set periodically. Otherwise, it is executed every time a command is issued through the host. The frequency of executing an inquiry is usually about 1 minute and can be adjusted by setting a value in the register on the baseband side via HCI at the host. Other Bluetooth modules can also be queried, and as a consequence, they must be kept in sync for 1 minute ± any time in order to avoid synchronous lookup in the same phase.

Inquiry uses 32 of the 79 hopping frequencies in total and 32 selections are independently determined by Bluetooth address. The inquiry response consists of an A_train of 256 eight-frame length trains consisting of 16 hopping frequencies out of 32 hopping frequencies, and 256 B_ trains of eight frame lengths consisting of the remaining 16 hopping frequencies of 32. It consists of two repetitions of the train.

In the inquiry mode, two transmissions and two receptions are performed in one transmission period of the normal connection mode, and the frequency also uses a different frequency. This is 1600hops / s in normal mode but 3200hops / s in inquiry and paging mode. This is to find a module quickly by sending many inquiry messages in a short time. A single train consists of eight frames, each frame consists of transmission and reception, and each transmission can transmit two inquiry packets, thus transmitting sixteen frequencies in one single train.

The frequency hopping order is by Bluetooth address and the hopping phase by Bluetooth clock. That is, when a Bluetooth address, a Bluetooth clock, and a transmit / receive selection are input to an input of a mapping box, a hopping frequency selection output is output to the output.

This mode can be interrupted by high priority SCO links, such as voice signals, in which case the number of single trains of the query must be increased to increase the length of the query to make up for the disturbed portion.

On the other hand, the inquiry scan scans for 11.25ms in 9 frames with a period of 1.28 seconds, and the other period is standby or communicates with another master. Inquiry scan may be turned off by the host when there is a lot of communication. This mode can also be interrupted by high-priority SCO links, such as voice signals, in which case the length of the scan window should be increased to make up for the obstruction.

Inquiry response is performed for 8 times the period of inquiry scan when any module inquires, so it can gather information of all surrounding modules. During the inquiry scan, the entire interval is in receive mode, and the slave is triggered when a hop equal to its received frequency arrives during this period. When the slave is triggered, the slave module freezes the currently triggered hopping frequency, generates a random number, and sleeps or communicates with another master during this period. You wake up and wait for the freezing frequency to trigger again. When triggered again, it sends an FHS packet (Bluetooth address and clock) to indicate its presence. However, the master cannot send a reply to this response because of the train transmission, so the slave must transmit it repeatedly several times. Therefore, the slave transmits its information in an FHS packet and then adds an offset of 1 to the hopping phase, then freezes the hopping frequency plus 1, generates a random number, sleeps, retriggers, and responds. Repeat until.

6 is a flowchart illustrating a connection operation according to the Bluetooth standard. The inquiry operation collects Bluetooth address and clock information of all the surrounding modules, and then the module to transmit data performs the paging operation to establish a baseband connection while serving as a master. The paging operation is the actual connection operation, which is initiated through the HCI connection command (60-1). Upon receiving this command, the link manager requests the baseband side to establish a baseband connection with a module (slave) corresponding to a Bluetooth address, and sets a value in the baseband register to activate the paging operation. When the register value is set, the actual paging operation is done on the baseband side.

The baseband connection between the master and the slave transmits a page train to the slave at the baseband side of the master (60-3), and transmits an ID packet at the baseband side of the slave (60-4). In step S, the FHS packet is transmitted to the slave side (60-5), and the ID packet is transmitted again from the slave (60-6). When this operation is completed, the master proposes a connection by sending an LMP packet called an LMP host connection request to the slave (60-8, 9).

The LMP host connection request transmitted from the master to the slave is transmitted from the baseband of the slave to the HCI side (60-10), which is sent to the host of the slave (60-11). After the connection is granted at the slave's host, this information is transmitted via the LM and the baseband to the master's baseband and the HCI (60-12, 13, 14, 15). Accordingly, the host's LM sends a command to complete the LMP setup to indicate that the connection procedure is complete (60-16, 17), which is sent to the slave's host (60-18, 19). The LMP setup completion information sent from the LM of the slave is then passed to the HCI of the master (60-20, 21, 22), which is sent to the host to indicate that the connection establishment procedure is completed (60-23), and then mutual data. The transmission is made.

There is no further data transfer, and the master's host requests HCI disconnection (60-24), thus sending a command called LMP detach from the LM to the slave, notifying the slave side of the HCI disconnection (60-24). -25, 26, 27, 28), and the connection is terminated by notifying the host of the completion of the HCI connection (60-29).

On the other hand, if there are a plurality of modules to establish a connection, perform the above procedure for each module, instruct the module to be connected to operate in hold mode for a while, and then attempt to establish a connection with another module.

A module operating in the hold mode may perform a power save when a connection is established to perform an operation other than data transmission, for example, an inquiry, an inquiry scan, a page, a page scan, or when there is no data to be transmitted. For the moment, it sleeps for a certain hold time. In the case of the master, the LMP hold request (and hold time) is called to the link manager of modules that are already connected to perform the inquiry operation to collect information of other modules that are not currently connected or to establish a connection with other modules. Send a command to request to operate in hold mode for hold time. The master requires a hold mode change, and the slave sleeps during the hold time. In the case of a slave, when the connection is established with another master but there is no more data to be transmitted or received, the master requests the link manager of the LMP hold request (and hold time) to sleep during the hold time. Upon receiving all change requests from a slave, the master informs the slave of the sleep time (hold time), and the slave sleeps during the hold time. When the hold time times out, the sleeping slaves wake up and begin communicating with the master again.

1 and 2, the keyboard 12 and the keyboard 12 to determine the address of the Bluetooth module of the keyboard 12 and the mouse 14 to be connected and used wirelessly in the main body 10 equipped with the Bluetooth module and In the process of installing the mouse 14 startup program, the inquiry operation as shown in FIG. 5 is performed to store the Bluetooth module address. In addition, based on the Bluetooth module addresses of the keyboard 12 and the mouse 14 stored in the computer main body 10, a wireless link between the keyboard and the mouse is established every time the computer is turned on. When the data is transmitted and received through the transceivers 23, 24, 28, and 29, and the power is turned off, the radio link is released.

By the way, look at the application of the Bluetooth system between the computer and its peripheral devices, the main body of the computer acts as a master and the keyboard and mouse acts as a slave, the keyboard or mouse acting as a slave to the main body of the computer The data is transferred, and the computer body does not require data to be transmitted by a keyboard or a mouse. Accordingly, the present invention provides a wireless communication scheme suitable for such a special situation, that is, a situation in which data is transmitted only from a slave to a master.

Referring to FIG. 1, the computer main body 10 serving as a master is connected to the keyboard 12 and the mouse 14 in a process as shown in FIGS. 5 and 6, and the keyboard 12 and the mouse are simultaneously established. (14) Transmit specific packets that allow data transmission for each, i.e., POLL packets, via the RF transmitter, and alternately send two devices, the keyboard 12 and the mouse 14, while the connection continues. To let the connection continue.

On the other hand, the keyboard 12 and the mouse 14 receive the first POLL packet from the computer main body 10 through the RF receiver and then transmit the transmission data recognized through the input unit of the keyboard or the mouse through the RF transmitter. To send). Data transmitted from the keyboard 12 or the mouse 14 is received by the RF receiver, which is a wireless communication module mounted on the computer main body 10, and the received data is converted into a data format that can be recognized by the computer by the baseband processor. And transmitted to the computer main body 10. Receiving the transmitted data, the computer main body 10 examines the error of the data, outputs the result when there is no error, and transmits a response packet indicating that there is no error to the keyboard 12 or the mouse 14.

4 shows the format of a data packet used on a wireless link, which is included in the Bluetooth specification. The packet format is composed of an access code of 72 bits, a header of 54 bits, and a data area of 160 bits. The packet transmitted from the computer main body 10 to the keyboard 12 or the mouse 14 does not have a data area. However, only the information in the header area indicating the successful reception of data received from the keyboard 12 or the mouse 14 is required. The data transferred from the keyboard 12 or the mouse 14 to the computer main body 10 uses a packet format as shown in FIG. 4 and each area is defined as follows.

The 54-bit header area consists of AM_ADDR (Active Member Addresses) (3 bits), TYPE (4 bits), FLOW (1 bit), ARQN (Automatic ReQuest Number) (1 bit), SEQN (SEQuence Number) (1 bit). ), HEC (Header Error Check) (8 bits), and FEC (Forward Error Correction) (36 bits). The 160-bit data area is further divided into a payload header (1 byte), a payload (17 bytes), and a cyclic redundancy check (CRC) (2 bytes).

In this case, a specific value, that is, '1000' is designated in the TYPE area of the header area according to the feature of the present invention by using a reserved part in Bluetooth. In this way, the packet corresponding to the data area of the data packet is called a WD1 (Wireless DATA 1) packet. Key data input via the keyboard 12 or position information input via the mouse 14 in the WD1 packet is stored in a bitwise format, and the data is transmitted over the wireless link by attaching an access code and a header. To pass).

7 is a flowchart illustrating operations of the computer main body according to an embodiment of the present invention. Referring to FIG. 7, first, in step 71, the computer main body 10 is preset with an installation program and inquiry procedure. Thereafter, when it is powered on in step 72, it establishes a connection and transmits a first POLL packet. Thereafter, in step 73, a data packet (WD1 packet) is received, and in step 74, it is checked whether there is an error in the received packet. As a result of checking in step 74, if there is no error, the process proceeds to step 75, in which the ARQN area of the header area of the transport packet is set to '1', that is, the packet set to the ACK (ACKnowlege) message is input to the keyboard 12 or the mouse 14 To send). This is then sent to the keyboard 12 or mouse 14 to indicate that the data packet has been transmitted without error.

On the other hand, if there is an error as a result of the check in step 74, the process proceeds to step 76 to set the ARQN area of the header area of the transport packet to '0', that is, to transmit the packet set in the NAK (NonACknowledge) message to the keyboard or mouse do. This is then sent to the keyboard 12 or mouse 14 to indicate that there was an error in packet transmission. Steps 73, 74, 75, and 76 are repeatedly performed until the power is turned off. When the power is turned off, the operation is determined in step 77 and proceeds to step 78, and in step 78, the connection is released. Will end.

8 is an operation flowchart of a keyboard 12 or a mouse 14 according to an embodiment of the present invention. Referring to FIG. 8, first, in step 81, the keyboard 12 or the mouse 14 completes the connection setup with the computer main body 10, and then, in step 82, the first POLL packet transmitted from the computer main body 10 is received. Receive. Thereafter, in step 83, a data packet (WD1 packet) for positioning of key data or a mouse is transmitted, and in step 84, a response packet transmitted from the master, that is, the computer main body 10, is received. Thereafter, in step 85, it is checked whether the ARQN area of the header area is set to '1', that is, an ACK (ACKnowlege) message, so that the data packet transmitted in step 83 is transmitted without error. . If the check result is confirmed without an error, the next data packet is transmitted to the computer main body 10 in step 86.

On the other hand, if it is determined in step 85 that there is an error in the transmitted data packet, the process proceeds to step 87 to retransmit the previously transmitted data packet. Steps 84, 85, 86, and 87 are repeatedly performed until the power of the computer is turned off. When the power of the computer is turned off, it is checked in step 88 and proceeded to step 89. Terminates the operation because it disconnects.

The above configuration enables short-range wireless communication of a computer system using Bluetooth according to a feature of the present invention.

Meanwhile, in the above description of the present invention, specific embodiments have been described, but various modifications may be made without departing from the scope of the present invention. Therefore, the scope of the present invention should not be defined by the described embodiments, but by the equivalents of the claims and claims.

As described above, the present invention can provide a short range wireless communication method which is preferable to be utilized for a wireless interface between a computer and a peripheral device using Bluetooth.

Claims (8)

In the short-range wireless communication method using Bluetooth, Sequentially transmitting a predetermined packet allowing data transmission from the master side Bluetooth module to at least one slave side Bluetooth module, and receiving and demodulating the preset data packet transmitted from the slave side Bluetooth module to provide to the corresponding host. Process, Receiving a predetermined packet allowing data transmission from the master Bluetooth module from the slave Bluetooth module, and modulating the transmission data of the corresponding host to provide the master module with the Bluetooth module Wireless communication method. The short range wireless communication method of claim 1, wherein the master side Bluetooth module and the slave side Bluetooth module perform an inquiry operation and a connection operation in advance upon power-on. The Bluetooth module of claim 1, wherein the master-side Bluetooth module receives a preset data packet transmitted from the slave-side Bluetooth module, inspects an error of data, and transmits a preset response packet regarding the presence or absence of an error to the slave-side Bluetooth module. And wherein the slave-side Bluetooth module receives a preset response packet regarding the presence or absence of an error transmitted from the master-side Bluetooth module and retransmits the corresponding data packet when an error of transmission data occurs. The data packet of claim 3, wherein the data packet includes an access code, a header, and a data area, and a type area indicating a type of a packet in the header area is designated with a preset value, and the response packet is the access code and the header. And an area indicating a transmission confirmation of the packet in the header area is set to a preset value according to the presence or absence of the error. In the short-range wireless communication method applied to a computer system using Bluetooth, The Bluetooth module of the computer main body sequentially transmits a predetermined packet allowing data transmission from the Bluetooth module of the at least one peripheral device, and receives and demodulates the predetermined data packet transmitted from the Bluetooth module of the peripheral device. The process provided by the body, Each of the Bluetooth modules of the peripheral device receives a predetermined packet allowing data transmission from the Bluetooth module of the computer main body, modulates the transmission data of the corresponding host, and provides the same to the Bluetooth module of the computer main body. Short-range wireless communication method characterized by. The short range wireless communication method of claim 5, wherein the computer main body side Bluetooth module and the peripheral device side Bluetooth module perform an inquiry operation and a connection operation in advance when the computer main body side is powered on. The Bluetooth device of claim 5, wherein the Bluetooth module of the computer main body receives a preset data packet transmitted from the Bluetooth module of the peripheral device, examines an error of data, and transmits a preset response packet regarding the presence or absence of an error. Module, and the peripheral device-side Bluetooth module receives a preset response packet regarding the presence or absence of an error transmitted from the computer main body-side Bluetooth module, and retransmits the corresponding data packet in the case of a transmission data error. Communication method. The data packet of claim 7, wherein the data packet includes an access code, a header, and a data area, and a TYPE area within the header area is set to a preset value, and the response packet comprises the access code and a header area. The ARQN area in the header area is set to a preset value according to the presence or absence of the error.