Differences between BLE 5.2, BLE 5.1, BLE 4.0, and other BLE protocols

By sdga:NiceRF Wireless Technology Co., Ltd

NiceRF: A brief introduction to various BLE protocols such as BLE 5.2, BLE 5.1, and BLE 4.0.

What is Bluetooth protocol?

The Bluetooth protocol is a Bluetooth communication standard defined by the Bluetooth Special Interest Group (SIG). It has developed mature traditional Bluetooth and Bluetooth Low Energy (BLE) technologies.

Bluetooth, the transmission distance is from 2 to 50M in the previous Bluetooth 4.0 protocol, with a rate of 1Mbps, to 300M in the current Bluetooth 5.2 protocol, with a rate of 2Mbps. Among them, low-power Bluetooth can reduce power consumption to uA level during sleep.

Differences between BLE 5.2, BLE 5.1, BLE 4.0, and other BLE protocols

BLE 5.2:

Features: The transmission is the same as BLE 5.1. On the basis of BLE 5.1, it includes three functions: LE synchronization channel, enhanced ATT protocol, and LE power consumption control.

LE Sync Channel: The LE Sync Channel lays the foundation for implementing next-generation Bluetooth audio for Multi-Stream Audio and Audio Sharing applications based on broadcast audio streams. According to the core specification of version 5.2, a synchronization group can include up to 31 different synchronized audio streams, and in broadcast synchronization mode, an unlimited number of audio receivers within the communication range can simultaneously listen to the shared audio streams.

Enhanced ATT: The ATT protocol in the BLE 5.2 version has been improved (Enhanced Attribute Protocol), which is used to quickly read attribute values. This new function will improve the efficiency of information communication based on the ATT protocol and achieve fast service discovery (Fast Service Discovery). Service Discovery) and other functions. It is foreseeable that the fast service discovery function will be applied in the next-generation Bluetooth audio technology to realize the rapid exchange of relevant service information between audio devices.

LE Power Control: BLE 5.2 defines a bidirectional power control protocol for Bluetooth Low Energy (LE Power Control) that can be used to implement a variety of application scenarios, helping to further reduce power consumption and improve device connectivity while maintaining connectivity stability and reliability.

BLE 5.1:

Features: The transmission is the same as BLE 5.0. The difference between BLE 5.1 and BLE 5.0 is that the former adds direction finding and centimeter-level positioning functions. This newly added function of BLE 5.1 can replace the traditional WiFi-assisted positioning, which can make indoor positioning more accurate, and can also accurately locate the position of small objects to avoid item loss.

BLE 5.0:

Compared with BLE 4.2, BLE 5.0 doubles the data transmission speed, from 1Mbps to 2Mbps. Faster transfer speeds will double data transfer rates while improving spectral and energy efficiency, significantly reduce power consumption, and enable new higher-throughput applications such as audio, with single-packet data expanding from the original 20 bytes to a maximum of 256 bytes. The coverage of the BLE 5.0 standard will be four times that of BLE 4.2, which is about 300 meters. The BLE 5.0 broadcast communication capacity is upgraded from 31 bytes of BLE 4.2 to 255 bytes, and the enhanced broadcast capability will bring better beacons to create more location-based indoor positioning services and navigation services without the need for pairing and wiring Data transmission can be realized, and the indoor positioning accuracy is less than 1 meter, which improves the indoor positioning accuracy function.

BLE 4.2:

Features: LE connection security improvement, privacy protection, big data transmission implementation

LE connection security: From the definition of Spec, the pairing encryption links of BLE 4.0 and 4.1 are based on AES-CCM encryption, but since both parties of Bluetooth 4.1 share the same key, there are risks and vulnerabilities of being cracked. The pairing link of BLE 4.2 is encrypted by the Diffie-Hellman Key Exchange key exchange algorithm. Each device has a pair of key pairs, a public key and a private key. The private key is stored by itself, and the public key is disclosed to the other party. The encrypted file is encrypted by its own private key and the public key of the other party, and the receiver decrypts it through its own private key and the public key of the transmitting party, thereby effectively preventing the occurrence of the incident of the middleman cracking the key.

Privacy protection: Bluetooth will carry its own BD address (bluetooth device address) during the broadcast process, which is the only Bluetooth MAC address. It is very helpful in some applications, such as logistics tracking applications, and logistics devices can be fixed according to the BD address. . However, some applications do not want their BD address to be exposed to the monitoring of the master device. BLE 4.2 provides a flexible choice. BLE 4.2 stipulates that the slave device can choose to send a random BD address in broadcast mode, so that the master The device can obtain its real BD address only after it is connected to the device. In addition, the BD address of the device's broadcast mode is a random sequence.

Realization of big data transmission: BLE 4.1 supports single-packet data transmission of up to 23 bytes, and BLE 4.2 supports single-packet data transmission of up to 255 bytes, which greatly improves the data transmission rate.

BLE 4.1:

Features: Improved data transfer rate, allows master-slave coexistence, supports 32Bit UUID

Data transfer rate improvement: Compared with BLE 4.0, the maximum data transfer per packet of BLE 4.1 has been increased from 20 bytes to 23 bytes, increasing the data transfer rate by 15%.

Master-slave coexistence: The Link layer topology has been updated to allow a single-device master-slave to coexist at the same time (time slice rotation), and a master-to-multiple-slave connection topology.

Support 32Bit UUID: 32-Bit UUID refers to the UUID carried in the broadcast packet. The complete 128 Bit UUID is obtained by mapping the broadcast 32-Bit UUID, so that the effective broadcast data length in the broadcast packet is more.