Bluetooth technology is a short-distance communication technology, widely used in our life. In addition to the early Bluetooth headset, Bluetooth mouse, Bluetooth keyboard, etc., Bluetooth technology is now commonplace in the IOT. Not only about that, Bluetooth technology is also really common in the field of car networking. For example, the tire pressure detection is to transmit the tire pressure signal to the tire pressure monitoring controller through the Bluetooth technology through the pressure temperature sensor mounted on the tire valve. Vehicle tire pressure display and alarm.
Bluetooth technology features:
1) Bluetooth uses the worldwide 2.4G ISM band, which is available in the world without a license;
2) Bluetooth device micro-modular;
3) Data transfer between Bluetooth devices does not require complicated settings;
4) The data transmission rate is high and the transmission distance is long;
5) Has good anti-interference ability.
Bluetooth system composition
The Bluetooth system consists of a Bluetooth module, a Bluetooth protocol, a system application, and radio waves. Due to the extremely short wavelength used, the antenna, controller, encoder, and transceiver can be integrated into one micro module, referred to as the Bluetooth module, as shown in the following figure.
Baseband controller: It is a key module in Bluetooth module. Its main function is to process the data stream in real time in the CPU controller, such as data grouping, encryption, decryption, verification, error correction, etc.
Program memory unit: protocol of software for storing Bluetooth technology;
Data storage: used to store data to be processed;
RF transceiver: responsible for receiving or transmitting high frequency communication radio waves;
Transceiver and serial interface: It is the two interface modes of the Bluetooth module and the host controller, which can be selected according to the connection mode;
Test module: In addition to the test function, it also provides relevant certifications and specifications as optional modules.
Bluetooth data transmission and data security
The Bluetooth module divides the data into short and flexible packets. After each packet is sent, it changes the frequency of transmission and reception, called Frequency Hopping (AFH).
Frequency hopping technology is one of the core technologies for ensuring signal security and avoiding interference. It works by dividing the 2.4 GHz ISM band into 40 channels, each with a channel spacing of 2 MHz. For each connection, the radio transceiver continuously hops from one channel to another in a certain code sequence, and then Change the frequency of transmission and reception in a random manner.
Bluetooth technology also attaches great importance to the protection of transmitted data, such as data processing and anti-eavesdropping. Low-power Bluetooth uses a 128-bit key and a 128-bit data block to weave the code. At the same time, the effective range of Bluetooth technology is relatively short, and the processing of data can only be used in this range, which is also indirect. Improve the security of your data.
Development of Bluetooth technology
The application of the Bluetooth module is getting wider and wider, from Bluetooth 2.0, 3.0, 4.0, 4.2 and now Bluetooth 5, can be said that developing rapidly. In general, the technology of the Bluetooth module is getting better and better, the volume is getting smaller and smaller, and the power consumption is getting lower and lower (some Bluetooth modules can work for several years using a 3V button battery or a pair of AAA batteries). At the same time, the transmission speed is getting faster and faster, the distance is getting farther and farther, and the security and anti-interference are getting stronger and stronger.
Bluetooth in the automotive field
With the development of Bluetooth technology, Bluetooth will be more and more used in vehicles. Data received by the tire pressure monitoring sensor can be transmitted to the relevant device by Bluetooth; future Bluetooth technology can also achieve wireless automatic diagnosis for vehicle failure. Moreover, combined with Internet technology, and realize the network management of vehicles, roads and people, which is referred to as the Bluetooth technology of the vehicle network.
