Bluetooth is a short-range wireless communication technology based on the 2.4 GHz ISM band. It has the characteristics of low power consumption, low cost, and convenience. It is widely used in smartphones, computers, wireless remote control, and other scenarios. It is one of the mainstream technologies to achieve wireless communication. Since the first version of Bluetooth was released by the Bluetooth Special Interest Group (SIG) in 1999, Bluetooth technology has been developed for over 20 years, from Bluetooth 1.0 to Bluetooth 5.4. Each version has an iterative update of different features. Bluetooth 1.0 ~ 3.0 is mainly related to the classic Bluetooth; this article focuses on the iterative characteristics of Bluetooth Low Energy versions (Bluetooth 4.0 and later versions).
- The Bluetooth Special Interest Group (SIG), founded in 1998, is a non-profit organization promoting Bluetooth technology with more than 36,000 members worldwide.
- The Bluetooth SIG focuses primarily on the following activities
– Create a Bluetooth specification
– Bluetooth interoperability driven by certified programs
– Increase Bluetooth visibility
- Development of Bluetooth Standard
Table of Contents
Bluetooth 4.0 Key Features
Bluetooth 4.0 is the first version to introduce the LE standard, and the main advantage is low power consumption. A microgrid architecture of point-to-point connection is defined. The Peripheral end establishes data connection through Advertising and the Central end. Advertising and Peripheral Connection can sleep in low power after data sending and receiving hours. The Central terminal establishes a data connection through the Scan and Peripheral terminals, and the Scan and Central Connection can enter a low-power sleep state outside of the data transceiver task time.
There are essential features to achieve point-to-point connection.
- Increase LEPHY
- Add LE Link Layer
- Add LE test mode
- ATT/GATT
- AES encryption and Security Manager (SM)
- Enhancements to L2CAP, GAP, and HCI for LE
Bluetooth 4.1 Key Features Evolution
Bluetooth 4.1 features minor changes, mainly compatible with BR / EDR and Blackrock Municipal Income Trust II. At the same time, while the underlying link can support different roles and the introduction of LE Privacy features, Bluetooth addresses can be hidden; users do not have to worry about Bluetooth devices being tracked to achieve privacy protection.
- LE dual-mode topology and Dual mode Addressing: Compared to the previous version, the topology structure has been expanded to allow dual-mode BR / EDR and Blackrock Municipal Income Trust II, and multiple roles can exist at the link layer.
- LE L2CAP connection-oriented channel: Provides more efficient data transfer between two Bluetooth low-energy devices, allowing multiple logical channels to exist simultaneously.
- Low duty cycle directed adv: Direct broadcast adds a low duty mode, which can be connected for longer durations and lower instantaneous broadcast power consumption.
- LE Privacy1.1: The basic concept of Privacy addresses the privacy protection of devices.
- LE Ping: The device can regularly check whether the peer device is online and whether the ordinal data number of the encrypted management is correct through the PingCommand
Bluetooth 4.2 Main features Evolution.
The significant changes to Bluetooth 4.2 include increasing the size of a single PDU, improving the data transfer rate, and increasing the user experience when interacting with data. In addition, LE secure connection increases privacy protection, enabling LE secure connection to prevent data decryption by peripheral equipment or sniffers.
- LE Data Packet Length Extension: The maximum data length of the PDU is 257 bytes, compared with the previous version of the PDU’s full data length of 33 bytes, which can improve the data throughput of the link.
- LE Secure Connection: Using ECDH for crucial exchange and LTK generation provides a higher level of protection against eavesdropping and MITM.
- Link layer Privacy: The RPA parsing function is changed from the host side to the link layer, which can identify the opposite side equipment more quickly and improve the flexibility of operation.
- Link layer extended scanner filter policies: Scan white list filtering adds a unique mechanism.
Bluetooth 5.0 Main Features Evolution
Bluetooth 5.0 changes are more significant, supporting 2MPHY, and the transmission rate is twice that of the previous. Users can experience a significant speed increase, while the addition of LongRang to achieve a longer transmission distance and LE Advertising Extensions to expand the scope of broadcast use, whether, in the channel, PHY, data length, and broadcast features have been greatly improved.
- Add 2 Mbps LE PHY: 2M PHY is an optional support PHY, with a rate of 2Mkbps, which is 1 times higher than 1M PHY data bandwidth.
- Increased LE Long range, S2 (500kbps), S8 (125Kbps): Longer transmission distances can be achieved.
- Add high-duty cycle non-connectable ADV: The minimum broadcast interval has been reduced from 100ms to 20ms, which enables faster scanning by the opposite end device.
- LE ADV Extensions: Extend ADV uses 40 channels instead of the previous 3; Allows for a larger ADV PDU (31bytes – > 254bytes); Adds periodic broadcasts; Allows multiple broadcast sets to exist simultaneously (up to 16)
- LE Channel Selection Algorithm #2: The FH algorithm has only 12 different FH sequences, and the new FH algorithm 2 is more random.
- Higher output power: Increase the maximum transmission power from 10 mW in 4.0 / 4.1 / 4.2 to 100 mW.
Bluetooth 5.1 Main Features Evolution
Bluetooth 5.1 mainly adds a direction-finding function, which provides technical support for indoor positioning service.
- Angle of Arrival (AoA) and Angle of Departure (AoD): Added AOA / Alpine Total Dynamic Dividend technology principle to orient equipment and provide location services.
- Advertising Channel Index: Allows broadcast events to be incremented in any order on three or several primary channels, whereas previous versions only allowed sequential increments on three primary channels.
- GATT Caching: Whenever the client device is connected, it performs “service discovery” to see what the server device supports, which consumes time and power. With the addition of GATT Caching in Bluetooth 5.1, clients can skip the service discovery process without any changes on the server side, which means faster connections and less energy consumption.
- Periodic Advertising Sync Transfer: Added to send scanned periodic broadcast synchronization information to another device via an ACL connection.
Bluetooth 5.2 Main Features Evolution
The changes to Bluetooth 5.2 are more evident than other changes, mainly for audio applications. It allows the transmission of time-limited data to one or more devices for time synchronization processing; the primary use cases are private audio sharing, public audio broadcasting, auxiliary reception hearing aids, etc.
- LE Isochronous Channel: A time-dependent data transmission channel and transmission strategy are defined for low latency audio data transmission, with the addition of a connected channel (CIS) and a connectionless channel (BIS).
- LE Power Control: Allows the terminal device to initiate a request to modify the transmitting power of the terminal device according to the received signal strength and its own receiving sensitivity to save energy.
- Enhanced Attribute Protocol (EATT): EATT can multiplex data in parallel without affecting each other, reducing congestion when multiple applications use Bluetooth low-energy devices, thereby decreasing end-to-end application latency and providing a better user experience.
Bluetooth 5.3 Main Features Evolution
The main change direction of Bluetooth 5.3 is to reduce power consumption, reduce device latency, improve anti-interference capabilities, and improve security performance.
- AdvDataInfo in Periodic ADV: Add the advDataInfo field in the periodic broadcast field, you can set whether the current data has been received through the ADI field, and if it is, duplicate data can be discarded to save data processing time.
- LE Enhanced Connection Update: It can quickly and effectively switch from a lower bandpass rate to a higher bandpass rate to cope with sudden big data transceivers. It can quickly reduce the current bandwidth after the considerable data interaction is completed to save energy.
- LE Channel Classification: Added Peripheral can be based on its packet quality, surrounding channel interference, and other information; by sending suggested channel requests to central, central can make appropriate decisions to obtain the best channel to avoid interfering with larger channels, where peripheral devices were unable to send channel information to significant appliances in previous versions.
- Host to controller encryption key control enhancements: Increasing the length of the encryption key can obtain the function through negotiation, and the minimum key length is specified to improve the link security.
Bluetooth 5.4 Main Features Evolution
Bluetooth 5.4 changes relatively little, mainly for periodic broadcast response (PAwR) features, for the fast-growing electronic shelf label (ESL) market, and provides a standard protocol framework, further expanding the scope of the Bluetooth market.
- Advertising Coding Selection: When sending an extended broadcast, the Host can specify which codec to use on the LEPHY.
- Encrypted Advertising Data: Allows ADV data to be encrypted using pre-shared session keys to avoid ADV-based data tracking devices. Eavesdropping and attacks can be prevented with private addresses, enabling better privacy protection.
- LE GATT Security Levels Characteristics: Add the security level feature (SLC), which allows the client to determine the GATT server security conditions that must be met if access rights to all GATT features are to be granted to the end device.
- Periodic Advertising with Response: Whereas previous versions of periodic broadcasting could only communicate one way from the broadcaster to the observer, PAwR is a two-way interactive connectionless communication that enables a single access point to communicate bi-directionally with thousands of end nodes.
Bluetooth 5.4 + Possible Major Feature Evolution (Preview)
High Accuracy Distance Measurement, AKA Channel Sounding: Mainly used for fixing by distances scenarios.
Bluetooth version is backward compatible; the higher the version, the more influential the function. Bluetooth version iteration updates quickly, covering more and more application areas.
Wireless technologies are necessary for IoT. WiFi, Bluetooth Classic, and ZigBee can all be used to connect devices wirelessly. However, BLE is often viewed as the most optimal technology for IoT applications because of two main reasons:
Little power usage. Many Internet of Things (IoT) devices run on batteries and have long operating life requirements. For instance, in a warehouse setting, it would simply be impractical to replace the batteries in hundreds of sensors routinely.
The kind of data being transferred. A small amount of data can be transmitted using BLE. IoT devices like sensors that only need to transfer state data can really benefit from this.
A BLE gateway with an IP connection must receive data from a BLE-only device and then relay it to another IP device (or the Internet) to transfer it from a BLE-only device to the Internet.
Dusun supplies a range of IoT Bluetooth gateways composed of low-power embedded Bluetooth (BLE) modules to exchange data with intelligent Bluetooth/BLE compatible devices like beacons and sensors in real-time and send data securely and reliably to the cloud via Wi-Fi/Ethernet/LTE. We serve IoT, IIoT, especially RPM, and Indoor (AOA/RSSI) Positions.
