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  • Bluetooth Low Energy - BLE

    Bluetooth Low Energy wireless technology is introduced in Bluetooth v4.0 specification in December 2009. It consumes only a fraction of the power of Classic Bluetooth radios. In many cases it makes it possible to operate coin cell powered devices for more than a year without recharging. This low power consumption means that Bluetooth low energy wireless technology will allow sports and wellness, health care, human interface (HIDs) and entertainment devices to be easily added to one's Personal Area Network (PAN). This new version of the technology can be built into products such as watches, toys, medical sensors, gaming and sports consoles and remote controllers, which can then connect to host devices such as mobile phones and personal computers.

    Compared to Classic Bluetooth, Bluetooth Low Energy is intended to provide considerably reduced power consumption and cost while maintaining a similar communication range. Mobile operating systems including iOS, Android, Windows Phone and BlackBerry, as well as macOS, Linux, Windows 8 and Windows 10, natively support Bluetooth Low Energy.


    Bluetooth Dual-Mode

    Bluetooth Dual-Mode was introduced in 4.0 for backward compatibility purposes as many Tablets and Smartphones released at that time won’t support Bluetooth 4.0. The dual-Mode device offers high flexibility as it simultaneously supports both Classic and Low Energy devices.

    Dual-Mode devices make use of the advantages of both Classic & Low-Energy features. It allows a Bluetooth Speakers and Headsets to get connected to a Smartphone with less latency by making use of BLE functionality. Dual-Mode allows Speakers and Headsets to stream High-Quality HD audio over Classic Bluetooth and to enrich customer experience by faster Pairing, longer range and faster media control over Bluetooth Low Energy.


    Bluetooth Standard Version History and Key Changes

    1. Bluetooth 1.0 - Was invented in 1998 with an intent to provide a wireless alternative to RS-232 data cables. However, the technology was still immature and suffered from many problems. It is obsolete now.


    2. Bluetooth v1.1 - Ratified as IEEE Standard 802.15.1–2002. It fixed some of the problems in Bluetooth 1.0. Added features include possibility of non-encrypted channels, Received Signal Strength Indicator (RSSI) etc.


    3. Bluetooth 1.2 - Ratified as IEEE Standard 802.15.1–2005. Major enhancements included faster connection and discovery, support for adaptive frequency-hopping spread spectrum (AFH) which reduced interference, faster transmission speeds of up to 721kbit/s, Host Controller Interface (HCI) operation with three-wire UART, and Extended Synchronous Connections (ESCO), Introduced Flow Control and Retransmission Modes for L2CAP etc.


    4. Bluetooth 2.0 + EDR - Was released before 2005. The highlight of this standard was the support for Enhanced Data Rate (EDR) which uses a combination of phase-shift keying modulation (PSK) and GFSK to provide better data transfer speeds. The bit rate of EDR is 3 Mbit/s, although the maximum data transfer rate (allowing for inter-packet time and acknowledgements) is 2.1 Mbit/s.


    5. Bluetooth 2.1 + EDR - Was adopted by the Bluetooth SIG on 26 July 2007. The headline feature is secure simple pairing (SSP) which improved the security as well as the pairing experience, and extended inquiry response (EIR) which allowed better filtering of devices before a connection was established, and sniff subrating which reduces the power consumption in low-power mode.

    Among all the classic Bluetooth versions, v2.1 was the most popular and widely implemented due to its simplicity, extended range of 100 feet instead of 30 feet, and faster data transfer speeds of up to 3Mbps. 


    6. Bluetooth 3.0 + HS - Was adopted by the Bluetooth SIG on 21 April 2009. Bluetooth v3.0 + HS provides theoretical data transfer speeds of up to 24 Mbit/s, though not over the Bluetooth link itself. Instead, the Bluetooth link is used for negotiation and establishment, and the high data rate traffic is carried over a collocated 802.11 link. The main new feature is AMP (Alternative MAC/PHY), the addition of 802.11 as a high-speed transport. It introduced many new features such as Enhanced Power Control, Ultra-wideband, L2CAP Enhanced modes, Alternate MAC/PHY, Unicast Connectionless Data, etc. However, it suffered from a major drawback – high power consumption.


    7. Bluetooth 4.0 - Was adopted on 30 June 2010. It includes Classic Bluetooth, Bluetooth high speed and Bluetooth Low Energy (BLE) protocols. Bluetooth high speed is based on Wi-Fi(Bluetooth 3.0 + HS), and Classic Bluetooth consists of legacy Bluetooth protocols(Bluetooth 2.1 + EDR). Bluetooth Low Energy, previously known as Wibree, is a subset of Bluetooth v4.0 with an entirely new protocol stack.


    8. Bluetooth v4.1 - Was adopted on 4 December 2013. It is an incremental software update to Bluetooth v4.0 with no hardware change. It could now co-exist with LTE, allowed devices to support multiple roles simultaneously, and facilitated bulk data transfer rates. New features of v4.1 specification include: Mobile Wireless Service Coexistence Signaling; Train Nudging and Generalized Interlaced Scanning; Low Duty Cycle Directed Advertising; L2CAP Connection Oriented and Dedicated Channels with Credit-Based Flow Control; Dual Mode and Topology; LE Link Layer Topology ;802.11n PAL; Audio Architecture Updates for Wide Band Speech; Fast Data Advertising Interval; Limited Discovery Time.


    9. Bluetooth 4.2 - Was adopted on 2 December 2014 to accommodate features for the Internet of Things(IoT). The major improvements includes: Low Energy Secure Connection with Data Packet Length Extension; Link Layer Privacy with Extended Scanner Filter Policies; Internet Protocol Support Profile (IPSP) version 6 ready for Bluetooth Smart things to support connected home.


    10. Bluetooth 5.0 - Was adopted on 6 December 2016. This standard focuses on improving the connectivity and experience of the Internet of Things (IoT) by offering a seamless data flow. For BLE, it doubles the speed in bursts of up to 2Mbps within a limited range of up to 4 times the range of the previous generation with a compromise on data transfer speed. The major areas of improvement are: Slot Availability Mask (SAM); 2 Mbit/s PHY for LE; LE Long Range; High Duty Cycle Non-Connectable Advertising; LE Advertising Extensions; LE Channel Selection Algorithm #2; Higher Output Power (Added in CSA5 and integrated in v5.0); Removed Park State.


    Bluetooth 5.0 also introduced a cool feature called ‘Dual Audio’ which made it possible for two different Bluetooth devices such as wireless headphones or speakers to play audio at the same time from a single Bluetooth audio streaming device that supports this version. It is also possible to stream two different audio sources from the same streaming device to two different Bluetooth devices.


    11. Bluetooth v5.1 - Was adopted on 21 January 2019. The major areas of improvement are: Angle of Arrival (AoA) and Angle of Departure (AoD) which are used for location and tracking of devices; Advertising Channel Index; GATT Caching; Minor Enhancements batch 1 (HCI support for debug keys in LE Secure Connections; Sleep clock accuracy update mechanism; ADI field in scan response data; Interaction between QoS and Flow Specification; Block Host channel classification for secondary advertising; Allow the SID to appear in scan response reports; Specify the behavior when rules are violated); Periodic Advertising Sync Transfer; Models and Mesh-based model hierarchy Features Added in Core Specification Addendum (CSA) 6 – Integrated in v5.1 (Added in Core Specification Addendum (CSA) 6  - Integrated in v5.1); Removed Unit keys.


    12. Bluetooth 5.2 - Was adopted on 31 December 2019. Newly added features include LE Audio; Enhanced Attribute Protocol (EATT) which is an improved version of the Attribute Protocol (ATT); LE Power Control; LE Isochronous Channels etc. LE Audio announced in January 2020 will run on the Bluetooth Low Energy radio with lower power consumption. LE Audio also add features such as one set of headphones connecting to multiple audio sources or multiple headphones connecting to one source. It uses a new LC3 codec. LE Audio will also add support for hearing aids.



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