Bluetooth

Bluetooth is a wireless protocol utilizing short-range communications technology facilitating data transmissions over short distances from fixed and/or mobile devices, creating wireless personal area networks (PANs). The intent behind the development of Bluetooth was the creation of a single digital wireless protocol, capable of connecting multiple devices and overcoming issues arising from synchronization of these devices. Bluetooth provides a way to connect and exchange information between devices such as mobile phones, telephones, laptops, personal computers, printers, GPS receivers, digital cameras, and video game consoles over a secure, globally unlicensed Industrial, Scientific, and Medical (ISM) 2.4 GHz short-range radio frequency bandwidth. The Bluetooth specifications are developed and licensed by the Bluetooth Special Interest Group (SIG). The Bluetooth SIG consists of companies in the areas of telecommunication, computing, networking, and consumer electronics.

Uses

Bluetooth is a standard and communications protocol primarily designed for low power consumption, with a short range (power-class-dependent: 1 meter, 10 meters, 100 meters) based on low-cost transceiver microchips in each device.[2] Bluetooth enables these devices to communicate with each other when they are in range. The devices use a radio communications system, so they do not have to be in line of sight of each other, and can even be in other rooms, as long as the received transmission is powerful enough. Bluetooth device class indicates the type of device and the supported services of which the information is transmitted during the discovery process.

Bluetooth profiles

In order to use Bluetooth, a device must be compatible with certain Bluetooth profiles. These define the possible applications and uses of the technology.

List of applications

More prevalent applications of Bluetooth include :

- Wireless control of and communication between a mobile phone and a hands-free headset. This was one of the earliest applications to become popular.Wireless networking between PCs in a confined space and where little bandwidth is required.

- Wireless communications with PC input and output devices, the most common being the mouse, keyboard and printer.Transfer of files between devices with OBEX.

- Transfer of contact details, calendar appointments, and reminders between devices with OBEX.

- Replacement of traditional wired serial communications in test equipment, GPS receivers, medical equipment, bar code scanners, and traffic control devices.

- For controls where infrared was traditionally used.

- Sending small advertisements from Bluetooth enabled advertising hoardings to other, discoverable, Bluetooth devices.

- Two seventh-generation game consoles, Nintendo's Wii[4] and Sony's PlayStation 3 use Bluetooth for their respective wireless controllers.

- Dial-up internet access on personal computer or PDA using a data-capable mobile phone as a modem.

Bluetooth vs. Wi-Fi in networking

Bluetooth and Wi-Fi have different applications in today's offices, homes, and on the move: setting up networks, printing, or transferring presentations and files from PDAs to computers. Both are versions of unlicensed spread spectrum technology.

Bluetooth differs from Wi-Fi in that the latter provides higher throughput and covers greater distances, but requires more expensive hardware and higher power consumption. They use the same frequency range, but employ different modulation techniques. While Bluetooth is a replacement for a variety of applications, Wi-Fi is a replacement only for local area network access. Bluetooth can be thought of as wireless USB[citation needed], whereas Wi-Fi is wireless Ethernet[citation needed], both operating at much lower bandwidth[citation needed] than cable networking systems. However, this analogy is not entirely accurate since any Bluetooth device can, in theory, host any other Bluetooth device—something that is not universal to USB devices, therefore it would resemble more a wireless FireWire.

Bluetooth devices

Bluetooth exists in many products, such as telephones, printers, modems and headsets. The technology is useful when transferring information between two or more devices that are near each other in low-bandwidth situations. Bluetooth is commonly used to transfer sound data with telephones (i.e. with a Bluetooth headset) or byte data with hand-held computers (transferring files).

Bluetooth simplifies the discovery and setup of services between devices. Bluetooth devices advertise all of the services they provide. This makes using services easier because there is no longer a need to set up network addresses or permissions as in many other network.

Wi-Fi

Wi-Fi is more like a traditional Ethernet network, and requires configuration to set up shared resources, transmit files, and to set up audio links (for example, headsets and hands-free devices). It uses the same radio frequencies as Bluetooth, but with higher power resulting in a stronger connection. Wi-Fi is sometimes called "wireless Ethernet." This description is accurate as it also provides an indication of its relative strengths and weaknesses. Wi-Fi requires more setup, but is better suited for operating full-scale networks because it enables a faster connection, better range from the base station, and better security than Bluetooths.Bluetooth and Wi-Fi have different applications in today's offices, homes, and on the move: setting up networks, printing, or transferring presentations and files from PDAs to computers. Both are versions of unlicensed spread spectrum technology.

Bluetooth differs from Wi-Fi in that the latter provides higher throughput and covers greater distances, but requires more expensive hardware and higher power consumption. They use the same frequency range, but employ different modulation techniques. While Bluetooth is a replacement for a variety of applications, Wi-Fi is a replacement only for local area network access. Bluetooth can be thought of as wireless USB, whereas Wi-Fi is wireless Ethernet, both operating at much lower bandwidth than cable networking systems. However, this analogy is not entirely accurate since any Bluetooth device can, in theory, host any other Bluetooth device—something that is not universal to USB devices, therefore it would resemble more a wireless FireWire.

Bluetooth devices

Bluetooth exists in many products, such as telephones, printers, modems and headsets. The technology is useful when transferring information between two or more devices that are near each other in low-bandwidth situations. Bluetooth is commonly used to transfer sound data with telephones (i.e. with a Bluetooth headset) or byte data with hand-held computers (transferring files).

Bluetooth simplifies the discovery and setup of services between devices. Bluetooth devices advertise all of the services they provide. This makes using services easier because there is no longer a need to set up network addresses or permissions as in many other network.

Wi-Fi

Wi-Fi is more like a traditional Ethernet network, and requires configuration to set up shared resources, transmit files, and to set up audio links (for example, headsets and hands-free devices). It uses the same radio frequencies as Bluetooth, but with higher power resulting in a stronger connection. Wi-Fi is sometimes called "wireless Ethernet." This description is accurate as it also provides an indication of its relative strengths and weaknesses. Wi-Fi requires more setup, but is better suited for operating full-scale networks because it enables a faster connection, better range from the base station, and better security than Bluetooths.

Computer requirements

A typical Bluetooth USB dongle An internal notebook Bluetooth card (14×36×4 mm)A personal computer must have a Bluetooth adapter in order to be able to communicate with other Bluetooth devices (such as mobile phones, mice and keyboards). While some desktop computers and most recent laptops come with a built-in Bluetooth adapter, others will require an external one in the form of a dongle.Unlike its predecessor, IrDA, which requires a separate adapter for each device, Bluetooth allows multiple devices to communicate with a computer over a single adapter.

Operating system support

Apple has supported Bluetooth since Mac OS X v10.2 which was released in 2002.
For Microsoft platforms, Windows XP Service Pack 2 and later releases have native support for Bluetooth. Previous versions required users to install their Bluetooth adapter's own drivers, which were not directly supported by Microsoft. Microsoft's own Bluetooth dongles (packaged with their Bluetooth computer devices) have no external drivers and thus require at least Windows XP Service Pack 2.

Linux has two popular Bluetooth stacks, BlueZ and Affix. The BlueZ stack is included with most Linux kernels and it was originally developed by Qualcomm. The Affix stack was developed by Nokia. FreeBSD features Bluetooth support since its 5.0 release. NetBSD features Bluetooth support since its 4.0 release. Its Bluetooth stack has been ported to OpenBSD as well.

Specifications and features

The Bluetooth specification was developed in 1994 by Jaap Haartsen and Sven Mattisson, who were working for Ericsson Mobile Platforms in Lund, Sweden. The specification is based on frequency-hopping spread spectrum technology.
The specifications were formalized by the Bluetooth Special Interest Group (SIG). The SIG was formally announced on May 20, 1998. Today it has a membership of over 7000 companies worldwide. It was established by Ericsson, IBM, Intel, Toshiba, and Nokia, and later joined by many other companies.

Bluetooth 1.0 and 1.0B

Versions 1.0 and 1.0B had many problems, and manufacturers had difficulty making their products interoperable. 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

Ratified as IEEE Standard 802.15.1-2002.Many errors found in the 1.0B specifications were fixed.Added support for non-encrypted channels.Received Signal Strength Indicator (RSSI).

Bluetooth 1.2

This version is backward-compatible with 1.1 and the major enhancements include the following:Faster Connection and DiscoveryAdaptive frequency-hopping spread spectrum (AFH), which improves resistance to radio frequency interference by avoiding the use of crowded frequencies in the hopping sequence.Higher transmission speeds in practice, up to 721 kbit/s, as in 1.1.Extended Synchronous Connections (eSCO), which improve voice quality of audio links by allowing retransmissions of corrupted packets, and may optionally increase audio latency to provide better support for concurrent data transfer.Host Controller Interface (HCI) support for three-wire UART.Ratified as IEEE Standard 802.15.1-2005.

Bluetooth 2.0

This version, specified on November 10, 2004, is backward-compatible with 1.1. The main enhancement is the introduction of an Enhanced Data Rate (EDR) for both data (ACL) and voice (eSCO) packets. The nominal signalling rate of EDR is about 3 megabits per second, although the practical data transfer rate is 2.1 megabits per second. This additional throughput is obtained by using a different modulation scheme for radio transmission of the data payload. Standard or Basic Rate transmission uses the Gaussian Frequency Shift Keying (GFSK) method, while EDR uses a combination of GFSK and Phase Shift Keying (PSK).

According to the 2.0 specification, EDR provides the following benefits :

- Three times faster transmission speed — up to 10 times in certain cases (up to 2.1 Mbit/s).

- Lower power consumption through a reduced duty cycle.

- Simplification of multi-link scenarios due to more available bandwidth.

The Bluetooth Special Interest Group (SIG) published the specification as "Bluetooth 2.0 + EDR" which implies that EDR is an optional feature. In some cases it is not clear whether a product claiming to support "Bluetooth 2.0" actually supports the EDR higher transfer rate. At least one commercial device, the HTC TyTN pocket PC phone, states "Bluetooth 2.0 without EDR" on its data sheet.

Bluetooth 2.1

Bluetooth Core Specification Version 2.1 is fully backward-compatible with 1.1, and was adopted by the Bluetooth SIG on July 26, 2007. This specification includes the following features :

- 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, as well as other information like the time of day, and pairing information.

- 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 expected to benefit the most, with mouse and keyboard devices increasing the battery life by a factor of 3 to 10. It 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.

- 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).Secure Simple Pairing: radically improves the pairing experience for Bluetooth devices, while increasing the use and strength of security. It is expected that this feature will significantly increase the use of Bluetooth.Near Field Communication (NFC) cooperation: automatic creation of secure Bluetooth connections when NFC radio interface is also available. 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 centimeters). 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 of Bluetooth

- Broadcast Channel : enables Bluetooth information points. This will drive the adoption of Bluetooth into mobile phones, and enable advertising models based around users pulling information from the information points, and not based around the object push model that is used in a limited way today.

- Topology Management : enables the automatic configuration of the piconet topologies especially in scatternet situations that are becoming more common today. This should all be invisible to the users of the technology, while also making the technology just work.

- Alternate MAC PHY : enables the use of alternative MAC and PHY's for transporting Bluetooth profile data. The Bluetooth Radio will still be used for device discovery, initial connection and profile configuration, however when lots of data needs to be sent, the high speed alternate MAC PHY's will be used to transport the data. This means that the proven low power connection models of Bluetooth are used when the system is idle, and the low power per bit radios are used when lots of data needs to be sent.

- QoS improvements : enable audio and video data to be transmitted at a higher quality, especially when best effort traffic is being transmitted in the same piconet.

High-speed Bluetooth

On 28 March 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 synchronizing 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.

Bluetooth 3.0

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.[15] Expected use cases include watches displaying Caller ID information, sports sensors monitoring your heart rate during exercise, as well as medical devices. The Medical Devices Working Group is also creating a medical devices profile and associated protocols to enable this market. Battery life for devices using Bluetooth low energy technology is designed to be up to one year.