Eight characteristics of Bluetooth technology Bluetooth is a technical specification of short-range wireless communication. Its initial goal is to replace the wired cable connection on various digital devices such as existing handheld computers and mobile phones. At the beginning of the development of the Bluetooth specification, it established a unified global goal and released it to the world. The working frequency band is the 2.4 GHz Industrial, Scientific and Medical (ISM) band that is globally and uniformly open. From the current application, due to the small size and low power of Bluetooth, its applications are not limited to computer peripherals and can be integrated into almost any digital device, especially those that do not require high data transfer rates. Portable device. The characteristics of Bluetooth technology can be summarized as follows:
(1) Globally applicable: Bluetooth operates in the 2.4 GHz ISM band, and the ISM band in most countries in the world ranges from 2.4 to 2.4835 GHz. It is not necessary to apply for a license from the radio resource management departments in various countries.
(2) Voice and data can be transmitted at the same time: Bluetooth uses circuit-switched and packet-switched technologies to support asynchronous data channels, three-way voice channels, and channels for simultaneous transmission of asynchronous data and synchronous voice. Each voice channel has a data rate of 64 kbit/s and the speech signal encoding uses pulse code modulation (PCM) or continuous variable slope incremental modulation (CVSD) methods. When data is transmitted using an asymmetric channel, the maximum rate is 721 kbit/s and the reverse is 57.6 kbit/s. When data is transmitted using a symmetric channel, the highest rate is 342.6 kbit/s. Bluetooth has two link types: Asynchronous Connection-Less (ACL) links and Synchronous Connection-Oriented (SCO) links.
(3) A temporary ad-hoc connection can be established: According to the role of the Bluetooth device in the network, it can be divided into a master device and a slave device (Slave). The master device is a Bluetooth device that actively initiates a connection request when a network connection is established. When several Bluetooth devices are connected to a piconet, only one master device is included, and the rest are slave devices. The piconet is the basic form of Bluetooth. The simplest piconet is a point-to-point communication connection between a master device and a slave device.
Through time-division multiplexing technology, a Bluetooth device can simultaneously synchronize with several different picophones. Specifically, the device participates in different piconets according to a certain time sequence, that is, participates in a piconet at a certain moment. At the next moment, you participate in another leather net.
(4) It has good anti-jamming capability: There are many types of radio equipment working in the ISM band, such as microwave ovens for home use, wireless local area networks (WLAN), HomeRF, etc., in order to resist well from these devices. Interference, Bluetooth uses Frequency Hopping to spread spectrum (Spread Spectrum), the 2.402 ~ 2.48GHz frequency band is divided into 79 frequency points, adjacent frequency interval 1MHz. After the Bluetooth device sends data at a certain frequency point, it jumps to another frequency point to send, and the order of the frequency points is pseudo-random. The frequency changes every 1600 times, and each frequency lasts 625 μs.
(5) The Bluetooth module is small and easy to integrate: Because the personal mobile device is small, the size of the embedded Bluetooth module should be smaller. For example, the external size of the Ericsson Bluetooth module ROK101008 is only 32.8mm x 16.8mm. × 2.95mm.
(6) Low power consumption: In the Connection state, the Bluetooth device has four operating modes - Active mode, Sniff mode, Hold mode, and Park mode. Active mode is the normal operating state, and the other three modes are the low power modes specified for energy saving.
(7) Open interface standard: In order to promote the use of Bluetooth technology, SIG makes all Bluetooth technical standards publicly available. Any unit or individual in the world can develop Bluetooth products as long as they eventually pass the SIG's Bluetooth product compatibility. Tests can be pushed to the market.
(8) Low cost: As the market demand expands, various suppliers have launched their own Bluetooth chips and modules, and the price of Bluetooth products has dropped rapidly.
(1) Globally applicable: Bluetooth operates in the 2.4 GHz ISM band, and the ISM band in most countries in the world ranges from 2.4 to 2.4835 GHz. It is not necessary to apply for a license from the radio resource management departments in various countries.
(2) Voice and data can be transmitted at the same time: Bluetooth uses circuit-switched and packet-switched technologies to support asynchronous data channels, three-way voice channels, and channels for simultaneous transmission of asynchronous data and synchronous voice. Each voice channel has a data rate of 64 kbit/s and the speech signal encoding uses pulse code modulation (PCM) or continuous variable slope incremental modulation (CVSD) methods. When data is transmitted using an asymmetric channel, the maximum rate is 721 kbit/s and the reverse is 57.6 kbit/s. When data is transmitted using a symmetric channel, the highest rate is 342.6 kbit/s. Bluetooth has two link types: Asynchronous Connection-Less (ACL) links and Synchronous Connection-Oriented (SCO) links.
(3) A temporary ad-hoc connection can be established: According to the role of the Bluetooth device in the network, it can be divided into a master device and a slave device (Slave). The master device is a Bluetooth device that actively initiates a connection request when a network connection is established. When several Bluetooth devices are connected to a piconet, only one master device is included, and the rest are slave devices. The piconet is the basic form of Bluetooth. The simplest piconet is a point-to-point communication connection between a master device and a slave device.
Through time-division multiplexing technology, a Bluetooth device can simultaneously synchronize with several different picophones. Specifically, the device participates in different piconets according to a certain time sequence, that is, participates in a piconet at a certain moment. At the next moment, you participate in another leather net.
(4) It has good anti-jamming capability: There are many types of radio equipment working in the ISM band, such as microwave ovens for home use, wireless local area networks (WLAN), HomeRF, etc., in order to resist well from these devices. Interference, Bluetooth uses Frequency Hopping to spread spectrum (Spread Spectrum), the 2.402 ~ 2.48GHz frequency band is divided into 79 frequency points, adjacent frequency interval 1MHz. After the Bluetooth device sends data at a certain frequency point, it jumps to another frequency point to send, and the order of the frequency points is pseudo-random. The frequency changes every 1600 times, and each frequency lasts 625 μs.
(5) The Bluetooth module is small and easy to integrate: Because the personal mobile device is small, the size of the embedded Bluetooth module should be smaller. For example, the external size of the Ericsson Bluetooth module ROK101008 is only 32.8mm x 16.8mm. × 2.95mm.
(6) Low power consumption: In the Connection state, the Bluetooth device has four operating modes - Active mode, Sniff mode, Hold mode, and Park mode. Active mode is the normal operating state, and the other three modes are the low power modes specified for energy saving.
(7) Open interface standard: In order to promote the use of Bluetooth technology, SIG makes all Bluetooth technical standards publicly available. Any unit or individual in the world can develop Bluetooth products as long as they eventually pass the SIG's Bluetooth product compatibility. Tests can be pushed to the market.
(8) Low cost: As the market demand expands, various suppliers have launched their own Bluetooth chips and modules, and the price of Bluetooth products has dropped rapidly.