Short-range wireless communication technologies include Wi-Fi, ZigBee, Bluetooth and Z-Wave. In the previous article, we introduced Z-Wave. In this issue, let's get to know Bluetooth technology together.


As a small-range wireless connection technology, Bluetooth has the characteristics of low power consumption, low cost, convenience and speed, and is widely used in wireless headphones, smart watches, wireless remote control and other scenarios, and is one of the mainstream technologies to realize wireless communication.

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Short-range wireless communication technology
Phase 3: Bluetooth

 Since the birth of the first Bluetooth version in 1999, Bluetooth technology has developed for more than 20 years. From Bluetooth 1.0 to Bluetooth 5.3, which functions have been upgraded by the continuously updated Bluetooth protocol?

Bluetooth 1.0
The transmission rate is 748~810kpbs, simplex transmission, communication is easily interfered with, and it is difficult to distinguish between master and slave devices.

Bluetooth 1.1
The transmission rate is between 748~810kpbs, and only simplex transmission can be used for work. It is easy to be interfered with by products of the same frequency and can distinguish between master and slave devices. This version supports the transmission requirements of Stereo sound effects, but the parameter indicators such as bandwidth, frequency, and response time cannot meet the requirements. It is not the best protocol applied to Stereo transmission.

Bluetooth 1.2
The transmission rate remains unchanged. On the basis of Bluetooth 1.1, it adds anti-interference frequency hopping function and supports single-channel playback, but the performance is still not ideal.

Bluetooth 2.0
Bluetooth 2.0 is an optimized and upgraded version of 1.2, and the transmission rate can reach about 2Mpbs. The Bluetooth module of this version can realize full-duplex operation mode and can transmit voice information in real-time bidirectional communication while transmitting files. Power consumption is relatively reduced, and stereo support begins.

Bluetooth 2.1
The Bluetooth module of this version has a pairing mechanism between mobile phones and NFC (Near Field Communication) for short-range communication.

Sniff Subrating function: It can realize setting the confirmation data sending interval between two devices. When we extend this time interval, we can reduce the power consumption of the Bluetooth chip.

The Bluetooth protocol of this version supports full-duplex communication mode, and data can achieve real-time bidirectional interaction.

Bluetooth 3.0
Using a new protocol, the transmission rate can reach 24Mbps, which greatly improves on the basis of Bluetooth 2.0 and supports video transmission.

The main features of the first three generations of Bluetooth technology standards, namely 1.x, 2.x, and 3.0 are high-speed wireless data transmission between devices, short distance, and high power consumption. The main applications are: establishing a one-to-one device connection with point-to-point network topology to transmit audio, video files, etc. Generally speaking, mobile phones, computers, tablets and other mobile devices are used as central devices; wireless headphones, wireless speakers, mice, keyboards, printers are used as peripheral devices. Due to high power consumption, devices are limited to rechargeable battery devices with certain capacity.

Bluetooth 4.0
Achieve extreme low power consumption; low cost and low latency; can achieve low latency of 3ms; there is also AES-128 encryption to achieve higher security while ensuring performance. Devices can be connected multiple times theoretically up to a distance of 100 meters.

Bluetooth versions after 4.0 belong to low-power Bluetooth.

Bluetooth 4.1
Realize connection to the network through IPV6 protocol to improve user access convenience and experience;

AES encryption technology: Through hardware encryption technology to obtain a more secure connection.

Bluetooth 4.2
Access the Internet through the 6LoWPAN protocol to improve data transfer rate; improve data transfer rate and enhance security.

Bluetooth 5.0
More advanced Bluetooth chips support independent reception of left and right channels for audio processing with stronger data processing capabilities and lower latency.

Improve transmission distance: up to 300 meters

Beacon: Provide broadcast services

Lossless transmission: support lossless audio source transmission with a bit depth of up to 24bit/192KHz

AOA function: Indoor positioning error within 1m for more accurate indoor positioning.

Bluetooth 5.2
Transmission rate is 42Mbps, and the theoretical transmission distance is 300 meters. Enhanced ATT protocol, LE power control and LE synchronous channel functions have been added.

Multiple masters and multiple slaves: Under the role of master-slave integration, 7 slave devices can be connected simultaneously, and it can also be connected as a slave role by another master device.

Long Range mode: Effectively improve transmission distance and increase communication range.

Support for large broadcast packets: Effectively improve transmission rate.

Extended broadcast packet reuse channel: Reuse 37 channels for transmission, with strong anti-interference ability and fast transmission.

LE power control function: Dynamically optimize the transmission power between connected devices according to changes in signal strength, while ensuring signal quality and reducing power waste.

Bluetooth 5.3
The transmission rate is the same as Bluetooth 5.2, with lower latency, longer battery life, and stronger anti-interference ability.

Support periodic broadcasting containing broadcast data information (ADI) to effectively improve communication efficiency;

ADI includes broadcast data ID (DID) and broadcast group ID (SID). Broadcast data ID is mainly used to distinguish different broadcast data content, and broadcast group ID is used to distinguish different broadcast groups.

New LE enhanced version connection update function, easy to achieve low power consumption;

New LE channel grading function can reduce mutual interference between devices;

New host sets the controller key length function to improve security;

Completely delete high-speed configuration (HS) and related technical specifications.

In summary, the higher the Bluetooth version, the more powerful the function. Bluetooth versions are backward compatible.

Nowadays, Bluetooth versions are updated very quickly. Compared with previous versions, the latest Bluetooth 5.3 has obvious improvements in transmission rate, stability, security and other aspects. The functions are stronger and more widely used. But for users, the most important thing is still consumer experience.

With the development of IoT market, Bluetooth technology is also growing rapidly. It has shown its strength in power consumption, number of connections, transmission speed and distance, security and other aspects. The category of interconnecting everything that supports Bluetooth devices continues to expand. Bluetooth technology is still the largest technology in IoT.