(1) Bluetooth module is small and easy to integrate: due to the small volume of personal mobile devices, the volume of Bluetooth chips embedded in them should be smaller.
(2) Low power consumption: when the Bluetooth device is in the communication connection state, there are four working modes – active mode, breathing mode, hold mode and sleep mode. Active mode is the normal working state, and the other three modes are the low power consumption modes specified for energy saving.
(3) Global application: Bluetooth works in the ISM band of 2.4GHz. The ISM band of most countries in the world ranges from 2.4 to 2.4835ghz. There is no need to apply for a license from the radio resource management department of each country to use this band.
(4) Simultaneous transmission of voice and data: Bluetooth adopts circuit switching and packet switching technology to support asynchronous data channel, three-way voice channel and channel for simultaneous transmission of asynchronous data and synchronous voice. The data rate of each voice channel is 64kbit / s, and the voice signal is encoded by pulse code modulation (PCM) or continuous variable slope incremental modulation (CVSD). When asymmetric channel is used to transmit data, the maximum rate is 721kbit / s and the reverse rate is 57.6kbit/s; When the symmetrical channel is used to transmit data, the maximum rate is 342.6kbit/s. Bluetooth has two link types: asynchronous connectionless link and synchronous connection oriented link
(5) It has good anti-interference ability: there are many kinds of radio equipment working in ISM frequency band, such as home microwave oven, WLAN and HomeRF. In order to resist the interference from these devices, Bluetooth uses frequency hopping to expand the spectrum, dividing the 2.402 ~ 2.48ghz frequency band into 79 frequency points with an interval of 1MHz between adjacent frequency points. After a Bluetooth device sends data at a certain frequency point, it jumps to another frequency point for transmission, and the arrangement order of frequency points is pseudo-random. The frequency changes 1600 times per second, and each frequency lasts 625us.
(6) Temporary peer-to-peer connection can be established: according to the role of Bluetooth devices in the network. It can be divided into master equipment and slave equipment. The master device is the Bluetooth device that initiates the connection request actively. When several Bluetooth devices are connected into a piconet, there is only one master device and the rest are slave devices. Piconet is the most basic network form of Bluetooth. The simplest piconet is a point-to-point communication connection composed of a master device and a slave device. Through time division multiplexing technology, a Bluetooth device can keep synchronization with several non directional piconets at the same time. Specifically, the device participates in different piconets according to a certain time sequence, that is, it participates in one piconet at one time and another piconet at the next time.
(7) Low cost: with the expansion of market demand, various suppliers have launched their own Bluetooth chips and modules, and the price of Bluetooth products has fallen rapidly.
(8) Open interface standard: in order to promote the use of Bluetooth technology, SIG makes all Bluetooth technical standards public. Any unit and individual in the world can conduct concurrent Bluetooth products. As long as it finally passes the compatibility test of SIG’s Bluetooth products, it can be introduced to the market.
