Bluetooth Versions

The Bluetooth specification was developed in 1994, and is based on frequency-hopping spread spectrum technology. The specifications were formalised in May 1998 by the Bluetooth Special Interest Group (SIG), established by Ericsson, IBM, Intel, Toshiba, and Nokia, and which now has a membership of over 11,000 companies worldwide.

Since the Bluetooth protocol was introduced in 1998, different specification versions have been released.

Bluetooth 1.0 and 1.0B

Versions 1.0 and 1.0B had many problems, the main one being the lack of communication among the devices. Versions 1.0 and 1.0B also included mandatory Bluetooth hardware device address (BD_ADDR) transmission in the Connecting process (rendering anonymity impossible at the protocol level), which was a major setback for certain services planned for use in Bluetooth environments.

Bluetooth 1.1

The core specification version 1.1 is the first successful operating version of Bluetooth, and corrected the majority of the bugs and problems found in former versions. It added support for non-encrypted channels and also added Received Signal Strength Indicator (RSSI). It was ratified as IEEE Standard 802.15.1-2002.

Bluetooth 1.2

This version was ratified as IEEE Standard 802.15.1-2005 and offered:

• backward compatibility with Bluetooth 1.1
• faster connection and discovery
• faster transmission speeds (up to 721 kbit/s),
• host controller interface (HCI) support for 3 wire UART
• extended Synchronous Connections (eSCO), which improved voice quality of audio links by allowing retransmissions of corrupted packets, and optionally increased audio latency to provide better support for concurrent data transfer
• adaptive frequency-hopping spread spectrum (AFH), which improved resistance to radio frequency interference by avoiding the use of crowded frequencies in the hopping sequence

Bluetooth 2.0

This version of the Bluetooth specification was released on November 10, 2004 and was backwards compatible with the previous version 1.1. According to the 2.0 specification, EDR provided the following benefits:

• reduced complexity of multiple simultaneous connections due to additional bandwidth
• 3 times faster transmission speed - up to 10 times (2.1 Mbit/s) in some cases.
• lower power consumption through a reduced duty cycle

The main difference was the introduction of an Enhanced Data Rate (EDR) for faster data transfer. The nominal rate of EDR is about 3 megabits per second, although the practical data transfer rate is 2.1 megabits per second. The additional throughput was obtained by using a different radio technology for transmission of the data. Standard (or basic) rate transmission uses Gaussian Frequency Shift Keying (GFSK) modulation of the radio signal; EDR uses a combination of GFSK and Phase Shift Keying (PSK) modulation.

The Bluetooth Special Interest Group (SIG) published the specification as "Bluetooth 2.0 + EDR" which implied that EDR was an optional feature. Some products claimed compliance to "Bluetooth 2.0" without supporting the higher data rate.

Bluetooth 2.1

Adopted by the Bluetooth SIG on July 26, 2007, Bluetooth Core Specification Version 2.1 is fully backward compatible with 1.1, and includes the following features:

• Secure Simple Pairing: radically improves the pairing experience for Bluetooth devices, while increasing the use and strength of security.
• Encryption Pause Resume: enables an encryption key to be refreshed, enabling much stronger encryption for connections that stay up for longer than 23.3 hours (one Bluetooth day).
• Sniff subrating: reduces the power consumption when devices are in the sniff low-power mode, especially on links with asymmetric data flows. Human interface devices (HID) are thought to benefit the most, with mouse and keyboard devices increasing their battery life by a factor of 3 to 10. Sniff subrating lets devices decide how long they will wait before sending keepalive messages to one another. Previous Bluetooth implementations featured keep alive message frequencies of up to several times per second. In contrast, the 2.1 specification allows pairs of devices to negotiate this value between them to as infrequently as once every 5 or 10 seconds.
• Extended inquiry response: provides more information during the inquiry procedure to allow better filtering of devices before connection. This information includes the name of the device, a list of services the device supports, plus other information like the time of day and pairing information.
• Near Field Communication (NFC) cooperation: automatic creation of secure Bluetooth connections when NFC radio interface is also available. This functionality is part of the Secure Simple Pairing where NFC is one way of exchanging pairing information. For example, a headset should be paired with a Bluetooth 2.1 phone including NFC just by bringing the two devices close to each other (a few centimetres). Another example is automatic uploading of photos from a mobile phone or camera to a digital picture frame just by bringing the phone or camera close to the frame.

Future Versions

Bluetooth TBD

The next version of Bluetooth after v2.1, code-named Seattle (the version number of which is TBD) has many of the same features, but is most notable for plans to adopt ultra-wideband (UWB) radio technology. This will allow Bluetooth use over UWB radio, enabling very fast data transfers of up to 480 Mbit/s, while building on the very low-power idle modes of Bluetooth.

Bluetooth Low Energy

On June 12, 2007, Nokia and Bluetooth SIG announced that Wibree will be a part of the Bluetooth specification, as an ultra-low power Bluetooth technology. Expected use cases include sports sensors monitoring your heart rate during exercise, watches displaying Caller ID information, and medical devices. Bluetooth low energy technology is designed for devices to have a battery life of up to one year.

Bluetooth High Speed

On March 28, 2006, the Bluetooth Special Interest Group announced its selection of the WiMedia Alliance Multi-Band Orthogonal Frequency Division Multiplexing (MB-OFDM) version of UWB for integration with current Bluetooth wireless technology.

UWB integration will create a version of Bluetooth wireless technology with a high-speed/high-data-rate option. This new version of Bluetooth technology will meet the high-speed demands of synchronising and transferring large amounts of data, as well as enabling high-quality video and audio applications for portable devices, multi-media projectors and television sets, and wireless VOIP.

At the same time, Bluetooth technology will continue catering to the needs of very low power applications such as mouse, keyboards, and mono headsets, enabling devices to select the most appropriate physical radio for the application requirements, thereby offering the best of both worlds.