BLUETOOTHTECHNOLOGYSUBMITTED TO : SUBITTED BY:Er. Ajay Kullar Hitender Thakur H.O.D. (CE & IT DEPTT.) Roll No. 006649005437 Shanky Kapil Roll No. 006649005444

BLUETOOTH TECHNOLOGYBluetooth is a specification for the use of low-power radio communications to wirelessly link phones, computers and other network devices over short distances. The name Bluetooth is borrowed from Harald Bluetooth, a king in Denmark more than 1,000 years ago. Bluetooth technology was designed primarily to support simple wireless networking of personal consumer devices and peripherals, including cell phones, PDAs, and wireless headsets. Wireless signals transmitted with Bluetooth cover short distances, typically up to 30 feet (10 meters). Bluetooth devices generally communicate at less than 1 Mbps.

Bluetooth networks feature a dynamic topology called a piconet or PAN. Piconets contain a minimum of two and a maximum of eight Bluetooth peer devices. Devices communicate using protocols that are part of the Bluetooth Specification. Definitions for multiple versions of the Bluetooth specification exist including versions 1.1, 1.2 and 2.0. Although the Bluetooth standard utilizes the same 2.4 Ghz range as 802.11b and 802.11g, Bluetooth technology is not a suitable Wi-Fi replacement. Compared to Wi-Fi, Bluetooth networking is much slower, a bit more limited in range, and supports many fewer devices. As is true for Wi-Fi and other wireless technologies today, concerns with Bluetooth technology include security and interoperability with other networking standards. Bluetooth was ratified as IEEE 802.15.1.

DEFINITIONSBluetooth is an open wireless protocol for exchanging data over short distances from fixed and mobile devices, creating personal area networks (PANs). It was originally conceived as a wireless alternative to RS232 data cables. It can connect several devices, overcoming problems of synchronization.Bluetooth technology is a wireless protocol that connects electronic devices while they are in close vicinity of one another. Instead of creating a local-area network (LAN) or a wide-area network (WAN), Bluetooth creates a personal-area network (PAN) just for you.

ORIGIN OF THE NAMEThe word Bluetooth is an version of Old Norse Bltnn or Danish Bltand, the name of the tenth-century king Harald I of Denmark and Norway, who united dissonant Scandinavian tribes into a single kingdom. The implication is that Bluetooth does the same with communications protocols, uniting them into one universal standard.

ORIGIN OF THE BLUETOOTH LOGO

The Bluetooth logo design merges the Germanic Runes analogous to the modern Latin letters H and B: (for Harald Bluetooth) (Hagall) and (Berkanan) merged together, forming a Bind Rune.

WHAT IS BLUETOOTH"Think of a connected world of electronic devices and appliances around you! You click on an icon for a device and you are linked to it, automatically and transparently"Bluetooth technology eliminates the need for numerous and inconvenient cable attachments for connecting fixed computers, mobile phones, mobile computers, handheld devices, digital cameras and even new breed of digital appliances. It will enable users to connect a wide range of computing and telecommunications devices easily and simply, without the need to buy, carry, or connect cables - quite often proprietary to a specific device. It delivers opportunities for rapid ad hoc connections, and the possibility of automatic, unconscious, connections between devices. It creates the possibility of using mobile data in a variety of applications.

Bluetooth is actually a standard for wireless communications between devices in a personal area network (PAN) using radio frequency for a short range (around 10 meters). So any two devices that follow the standard can communicate and exchange data between each other without the need of any connection to be made between them. A group of Bluetooth devices like a mobile phone, a digital camera, a hand held device etc. can instantly form a network with each other as soon as they are switched on. You could have a mobile phone in your pocket and you could be sending e-mails using your laptop without making any connection between your laptop and the mobile. Your refrigerator could be placing an order with the supermarket if your milk supply has been exhausted using your mobile phone.

Briefly, Bluetooth technologyuses radio waves in 2.4 GHz band - therefore, no line of sight is required supports multipoint, not just point to point works in a small confined area - 10 to 15 meters apart is able to support speeds of 1-2 Mbps today but will offer higher speeds in future chip sets are relatively inexpensive (though more expensive than IrDA)- $10 to $20 today in large quantities - will go down in future has significant industry support with over 1800 members in the industry consortium

HOW BLUETOOTH WORKS"Automatic communication between various devices within a small area in a house or an office makes it possible to provide unique and innovative services to a professional worker or a small group of workers using portable devices. Bluetooth technology has this potential and is coming along fast and quick. It will replace clumsy wires, make information transfer automatic without synchronization cradles and introduce many new applications. Technology visionaries hope that it will do what infra red could not do over the past six years."

Bluetooth is a high-speed, low-power microwave wireless link technology, designed to connect phones, laptops, PDAs and other portable equipment together with little or no work by the user. Unlike infra-red, Bluetooth does not require line-of-sight positioning of connected units. The technology uses modifications of existing wireless LAN techniques but is most notable for its small size and low cost. The current prototype circuits are contained on a circuit board 0.9cm square, with a much smaller single chip version in development. The cost of the device is expected to fall very fast, from $20 initially to $5 in a year or two. It is envisioned that Bluetooth will be included within equipment rather than being an optional extra. When one Bluetooth product comes within range of another, (this can be set to between 10cm and 100m) they automatically exchange address and capability details. They can then establish a 1 megabit/s link (up to 2 Mbps in the second generation of the technology) with security and error correction, to use as required.

This technology achieves its goal by embedding tiny, inexpensive, short-range transceivers into the electronic devices that are available today. The radio operates on the globally-available unlicensed radio band, 2.45 GHz (meaning there will be no hindrance for international travelers using Bluetooth-enabled equipment.), and supports data speeds of up to 721 Kbps, as well as three voice channels. The bluetooth modules can be either built into electronic devices or used as an adaptor. For instance in a PC they can be built in as a PC card or externally attached via the USB port.

Each device has a unique 48-bit address from the IEEE 802 standard. Connections can be point-to-point or multipoint. The maximum range is 10 meters but can be extended to 100 meters by increasing the power. Bluetooth devices are protected from radio interference by changing their frequencies arbitrarily upto a maximum of 1600 times a second, a technique known as frequency hopping. They also use three different but complimentary error correction schemes. Built-in encryption and verification is provided.

Moreover, Bluetooth devices won't drain precious battery life. The Bluetooth specification targets power consumption of the device from a "hold" mode consuming 30 micro amps to the active transmitting range of 8-30 milliamps (or less than 1/10th of a watt). The radio chip consumers only 0.3mA in standby mode, which is less than 3 % of the power used by a standard mobile phone. The chips also have excellent power-saving features, as they will automatically shift to a low-power mode as soon as traffic volume lessens or stops.

Bluetooth devices are classified according to three different power classes, as shown in the following table.

Power ClassMaximum OutputPower1100 mW(20 dBm)22.5 mW(4 dBm)31 mW(0 dBm)

But beyond untethering devices by replacing the cables, Bluetooth radio technology provides a universal bridge to existing data networks, a peripheral interface, and a mechanism to form small private ad hoc groupings of connected devices away from fixed network infrastructures. Designed to operate in a noisy radio frequency environment, the Bluetooth radio uses a fast acknowledgment and frequency hopping scheme to make the link robust. Bluetooth radio modules avoid interference from other signals by hopping to a new frequency after transmitting or receiving a packet..

Bluetooth guarantees security at the bit level. Authentication is controlled by the user by using a 128 bit key. Radio signals can be coded with 8 bits or anything upto 128 bits. The Bluetooth radio transmissions will conform to the safety standards required by the countries where the technology will be used with respect to the affects of radio transmissions on the human body. Emissions from Bluetooth enabled devices will be no greater than emissions from industry-standard cordless phones. The Bluetooth module will not interfere or cause harm to public or private telecommunications network.

The Bluetooth baseband protocol is a combination of circuit and packet switching. Slots can be reserved for synchronous packets. Each packet is transmitted in a different hop frequency. A packet nominally covers a single slot, but can be extended to cover up to five slots. Bluetooth can support an asynchronous data channel, up to three simultaneous synchronous voice channels, or a channel, which simultaneously supports asynchronous data and synchronous voice. It is thus possible to transfer the date asynchronously whilst at the same time talking synchronously at the same time. Each voice channel supports 64 kb/s synchronous (voice) link. The asynchronous channel can support an asymmetric link of maximally 721 kb/s in either direction while permitting 57.6 kb/s in the return direction, or a 432.6 kb/s symmetric link.

Modes of operation An interesting aspect of the technology is the instant formation of networks once the bluetooth devices come in range to each other. A piconet is a collection of devices connected via Bluetooth technology in an ad hoc fashion. A Piconet can be a simple connection between two devices or more than two devices. Multiple independent and non-synchronized piconets can form a scatternet. Any of the devices in a piconet can also be a member of another by means of time multiplexing. i.e a device can be a part of more than one piconet by suitably sharing the time. The Bluetooth system supports both point-to-point and point-to-multi-point connections. When a device is connected to another device it is a point to point connection. If it is connected to more that one (upto 7 ) it is a point to multipoint connection. Several piconets can be established and linked together ad hoc, where each piconet is identified by a different frequency hopping sequence.

All users participating on the same piconet are synchronized to this hopping sequence. If a device is connected to more than one piconet it communicates in each piconet using a different hopping sequence. A piconet starts with two connected devices, such as a portable PC and cellular phone, and may grow to eight connected devices. All Bluetooth devices are peer units and have identical implementations. A 3-bit MAC address is used to distinguish between units participating in the piconet. Devices synchronized to a piconet can enter power-saving modes called Sniff and hold mode, in which device activity is lowered. Also there can be parked units which are synchronized but do not have a MAC addresses. These parked units have a 8 bit address, therefore there can be a maximum of 256 parked devices.

Voice channels use either a 64 kbps log PCM or the Continuous Variable Slope Delta Modulation (CVSD) voice coding scheme, and never retransmit voice packets. The voice quality on the line interface should be better than or equal to the 64 kbps log PCM. The CVSD method was chosen for its robustness in handling dropped and damaged voice samples. Rising interference levels are experienced as increased background noise: even at bit error rates up 4%, the CVSD coded voice is quite audible.

The Air Interface & Frequency BandThe Bluetooth air interface is based on a nominal antenna power of 0dBm. The air interface complies with the FCC rules for the ISM band at power levels up to 0dBm. Spectrum spreading has been added to facilitate optional operation at power levels up to 100 mW worldwide. Spectrum spreading is accomplished by frequency hopping in 79 hops displaced by 1 MHz, starting at 2.402 GHz and stopping at 2.480 GHz. Due to local regulations the bandwidth is reduced in Japan, France and Spain. An internal software switch handles this. The maximum frequency ho

ping rate is 1600 hops/s. The nominal link range is 10 centimeters to 10 meters, but can be extended to more than 100 meters by increasing the transmit power. The Modulation is GFSK (Gaussian Frequency Shift Keying) with a BT=0.5. The Modulation index must be between 0.28 and 0.35. A binary one is represented by a positive frequency deviation, and a binary zero is represented by a negative frequency deviation. The symbol timing shall be better than 20 ppm.

Applications Bluetooth has a tremendous potential in moving and synchronizing information in a localized setting. Potential for Bluetooth applications is huge, because we transact business and communicate more with people who are close by than with those who are far away - a natural phenomenon of human interaction. The following list represents only a small set of potential applications - in future many more imaginative applications will come along:

By installing a Bluetooth network in your office you can do away with the complex and tedious task of networking between the computing devices, yet have the power of connected devices. No longer would you be bound to fixed locations where you can connect to the network. Each Bluetooth device could be connected to 200 other devices making the connection of every device with every other possible. Since it supports both point to point and point to multipoint it will virtually make the maximum number of simultaneously linked devices unlimited.

The Bluetooth technology connects all your office peripherals wirelessly. Connect your PC or notebook to printers, scanners and faxes without the ugly and trouble some cable attachments. You can increase your freedom by connecting your mouse or the keyboard wirelessly to your computer. If your digital cameras in Bluetooth enabled, you can send still or video images from any location to any location without the hassle of connecting your camera to the mobile phone on the wireline phone.

Bluetooth allows us to have three way phones. At home, your phone functions as a portable phone (fixed line charge). When you're on the move, it functions as a mobile phone (cellular charge). And when your phone comes within range of another mobile phone with built-in Bluetooth wireless technology it functions as a walkie-talkie (no telephony charge). In meetings and conferences you can transfer selected documents instantly with selected participants, and exchange electronic business cards automatically, without any wired connections.

Connect your wireless headset to your mobile phone, mobile computer or any wired connection to keep your hands free for more important tasks when you're at the office or in your car. Have automatic synchronization of your desktop, mobile computer, notebook (PC-PDA and PC-HPC) and your mobile phone. For instance, as soon as you enter your office the address list and calendar in your notebook will automatically be updated to agree with the one in your desktop, or vice versa.

Automatic Message Delivery: Compose e-mails on your portable PC while you're on an airplane. As soon as you've landed and switched on your mobile phone, all messages are immediately sent. Upon arriving at your home, the door automatically unlocks for you, the entry way lights come on, and the heat is adjusted to your pre-set preferences.

IBM researchers are working on a number of personal devices like a WatchPad that could be connected with other devices through Bluetooth. The Watch Pad is very thin and contains 8MB of RAM. They are also working on a version of CyberPhone called CyberPhone - that can project data onto a small mirror. The CyberPhone can show as much information as a small PDA because of high resolution VGA screen.

You enter the airport-waiting lounge, equipped with Bluetooth-enabled Internet ports. Via the ports, you and other guests use Bluetooth-enabled laptops, PDAs, and other devices to access your office or home-based servers via the airline server. Using voice-over IP, you also make "free" Internet voice calls courtesy of your airline.

The Current State of the Technology Bluetooth technology has moved fast in terms of standards adoption, early release of chip sets and a few demo products. Nonetheless, Bluetooth is in early stages of development from the point of view of its adoption in enduser applications. To be more specific, Bluetooth technology is in a period where first release of specifications have been developed and adopted by the core members. Chips sets have been developed by several vendors and have been released to systems integrators. Software development kits have also been released by major vendors. A number of developers conferences have been held in Europe and North America. Now, the second level of developers like 3COM and extended Systems have got into the act to develop systems development tools that business application developers can use.

APPLIED BY VARIOUS COMPANIESThe Ericsson Bluetooth Headset is a lightweight, wireless mobile phone headset, with a built-in Bluetooth radio chip that acts as a connector between the headset and the Bluetooth plug on the Ericsson phone. When your phone rings, you can answer by simply pressing a key on the headset. If you want to make a call, press the key on the headset and use voice recognition to initiate the call. The phone can be up to 10 meters (30 ft.) away, in a briefcase, your coat pocket, or even in another room while you speak and enjoy complete mobility without cables dangling about. Weighing a mere 20 grams (0.75 oz.), the Bluetooth Headset sits comfortably on either ear and can be used with Ericsson T28, T28 WORLD and R320 cellular phones.

Nokia displayed a Bluetooth headset that allows users wireless communication with their mobile phones over distances of up to 10 metres. Nokia and Fujifilm have been developing a prototype Mobile Imaging technology, allowing a modified Nokia 9110 Communicator containing a Bluetooth chip to receive images taken on a Bluetooth equipped Fujifilm digital camera. After adding a few lines of text, the user can send the received photograph to another Nokia Communicator, or to the Fujifilm Web service, where it could be viewed, printed or saved on a CD-R. By combining the ease of SMS messaging with digital photography, Mobile Imaging is a clear indication of the potential of Bluetooth.

The AutoPC is a Windows CE-based device that combines a computer with a car radio. It uses voice recognition technology to enable hands-free communication for the driver and enables mobile devices such as phones, PDAs, notebooks, pagers and so on to be docked. Xircom demonstrated the capabilities of its Compact Flash product by transferring voice data file between two Windows CE palm-sized PCs at a data rate of 721kB/sec. The device looks like any ordinary Compact Flash card, with the exception of a square plastic antenna attached to one end.

Some Bluetooth enabled products in the market:Ericsson R520 Bluetooth/WAP/GPRS/Triband Ericsson T36 Bluetooth/WAP/HSCSD/Triband Alcatel OneTouch 700 GPRS, WAP, Bluetooth TDK Bluetooth Product Range Bluetooth-enabled Nokia 9110 linked to a FujiFilm digital camera Ericsson Bluetooth GSM Headset Ericsson Communicator

Uses

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

A typical Bluetooth mobile phone headset

Nokia BH-208 headset internals.

WIRELESS KEY BOARD AND MOUSE

BLUE TOOTH PC HEAD SET

SIZE OF A NORMAL BLUETOOTH DEVICE

INTERNAL CHIP OF THE BLUETOOTH

Operating system support

Apple has supported Bluetooth since Mac OS X v10.2 which was released in 2002.[7]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.[8] 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[9] stack is included with most Linux kernels and was originally developed by Qualcomm.

Mobile phone requirements A mobile phone that is Bluetooth enabled is able to pair with many devices. To ensure the broadest support of feature functionality together with legacy device support, the Open Mobile Terminal Platform (OMTP) forum has recently published a recommendations paper, entitled "Bluetooth Local Connectivity"; see external links below to download this paper.This publication recommends two classes, Basic and Advanced, with requirements that cover imaging, printing, stereo audio and in-car usage.

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.[10] 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 11,000 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 Discovery Adaptive 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, than 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 of the Bluetooth specification was released on November 10, 2004. It is backward compatible with the previous version 1.2. The main difference is 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 is 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 with a gross air data rate of 1Mbit/s. EDR uses a combination of GFSK and Phase Shift Keying modulation (PSK) with two variants, /4-DQPSK and 8DPSK. These have gross air data rates of 2, and 3Mbit/s respectively.

According to the 2.0 specification, EDR provides the following benefits:Three times faster transmission speed up to 10 times (2.1Mbit/s) in some cases. Reduced complexity of multiple simultaneous connections due to additional bandwidth. Lower power consumption through a reduced duty cycle.

Bluetooth 2.1

Bluetooth Core Specification Version 2.1 is fully backward compatible with 1.2, and was adopted by the Bluetooth SIG on July 26, 2007.his specification includes the following features :-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 expected to benefit the most, with mouse and keyboard devices increasing their 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.

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. 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.

Bluetooth 3.0

The 3.0 specification[12] was adopted by the Bluetooth SIG on April 21st, 2009. Its main new feature is AMP (Alternate MAC/PHY), the addition of Wi-Fi as a high speed transport. Two technologies had been anticipated for AMP: Wi-Fi and UWB, but UWB is missing from the specification

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. 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.

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

Technical information

Bluetooth protocol stack Bluetooth is defined as a layer protocol architecture consisting of core protocols, cable replacement protocols, telephony control protocols, and adopted protocols.Mandatory protocols for all Bluetooth stacks are: LMP, L2CAP and SDPAdditionally, these protocols are almost universally supported: HCI and RFCOMM

L2CAP (Logical Link Control & Adaptation Protocol)Used to multiplex multiple logical connections between two devices using different higher level protocols. Provides segmentation and reassembly of on-air packets. In basic mode, L2CAP provides reliable sequenced packets with a payload configurable up to 64kB, with 672 bytes as the minimum mandatory supported size. In retransmission & flow control modes, L2CAP can be configured for reliable or isochronous data per channel by configuring the number of retransmissions and flush timeout.The EL2CAP specification adds an additional "enhanced mode" to the core specification, which is an improved version of retransmission & flow control modes.

SDP (Service Discovery Protocol)Used to allow devices to discover what services each other support, and what parameters to use to connect to them. For example, when connecting a mobile phone to a Bluetooth headset, SDP will be used to determine which Bluetooth profiles are supported by the headset (Headset Profile, Hands Free Profile, Advanced Audio Distribution Profile etc) and the protocol multiplexer settings needed to connect to each of them. Each service is identified by a Universally Unique Identifier (UUID), with official services (Bluetooth profiles) assigned a short form UUID (16 bits rather than the full 128)

HCI (Host/Controller Interface)Standardised communication between the host stack (e.g. a PC or mobile phone OS) and the controller (the Bluetooth I.C.) This standard allows the host stack or controller I.C. to be swapped with minimal adaptation.There are several HCI transport layer standards, each using a different hardware interface to transfer the same command, event and data packets. The most commonly used are USB (in PCs) and UART (in mobile phones and PDAs).

RFCOMM (Cable replacement protocol)Radio frequency communications (RFCOMM) is the cable replacement protocol used to create a virtual serial data stream. RFCOMM provides for binary data transport and emulates EIA-232 (formerly RS-232) control signals over the Bluetooth baseband layer.RFCOMM provides a simple reliable data stream to the user, similar to TCP. It is used directly by many telephony related profiles as a carrier for AT commands, as well as being a transport layer for OBEX over Bluetooth.

BNEP (Bluetooth Network Encapsulation Protocol)BNEP is used to transfer another protocol stack's data via an L2CAP channel. Its main purpose is the transmission of IP packets in the Personal Area Networking Profile. BNEP performs a similar function to SNAP in Wireless LAN.

AVCTP (Audio/Visual Control Transport Protocol)Used by the remote control profile to transfer AV/C commands over an L2CAP channel. The music control buttons on a stereo headset use this protocol to control the music playerAVDTP (Audio/Visual Data Transport Protocol)Used by the advanced audio distribution profile to stream music to stereo headsets over an L2CAP channel. Intended to be used by video distribution profile.

Telephone control protocolTelephony control protocol-binary (TCS BIN) is the bit-oriented protocol that defines the call control signaling for the establishment of voice and data calls between Bluetooth devices. Additionally, TCS BIN defines mobility management procedures for handling groups of Bluetooth TCS devicesTCS-BIN is only used by the cordless telephony profile, which failed to attract implementers. As such it is only of historical interest.

Point-to-Point Protocol (PPP) Internet standard protocol for transporting IP datagrams over a point-to-point linkTCP/IP/UDP Foundation Protocols for TCP/IP protocol suiteObject Exchange Protocol (OBEX) Session-layer protocol for the exchange of objects, providing a model for object and operation representationWireless Application Environment / Wireless Application Protocol (WAE/WAP) WAE specifies an application framework for wireless devices and WAP is an open standard to provide mobile users access to telephony and information services.

Communication and connection A master Bluetooth device can communicate with up to seven devices in a Wireless User Group. This network group of up to eight devices is called a piconet.A piconet is an ad-hoc computer network, using Bluetooth technology protocols to allow one master device to interconnect with up to seven active devices. Up to 255 further devices can be inactive, or parked, which the master device can bring into active status at any time.At any given time, data can be transferred between the master and one other device, however, the devices can switch roles and the slave can become the master at any time. The master switches rapidly from one device to another in a round-robin fashion. (Simultaneous transmission from the master to multiple other devices is possible, but not used much.)

Setting up connections

Any Bluetooth device will transmit the following information on demand:Device name. Device class. List of services. Technical information, for example, device features, manufacturer, Bluetooth specification used, clock offset. Any device may perform an inquiry to find other devices to connect to, and any device can be configured to respond to such inquiries. However, if the device trying to connect knows the address of the device, it always responds to direct connection requests and transmits the information shown in the list above if requested. Use of a device's services may require pairing or acceptance by its owner, but the connection itself can be initiated by any device and held until it goes out of range. Some devices can be connected to only one device at a time, and connecting to them prevents them from connecting to other devices and appearing in inquiries until they disconnect from the other device.

Pairing Pairs of devices may establish a trusted relationship by learning (by user input) a shared secret known as a passkey. A device that wants to communicate only with a trusted device can cryptographically authenticate the identity of the other device. Trusted devices may also encrypt the data that they exchange over the airwaves so that no one can listen in. The encryption can, however, be turned off, and passkeys are stored on the device file system, not on the Bluetooth chip itself. Since the Bluetooth address is permanent, a pairing is preserved, even if the Bluetooth name is changed. Pairs can be deleted at any time by either device. Devices generally require pairing or prompt the owner before they allow a remote device to use any or most of their services. Some devices, such as mobile phones, usually accept OBEX electronic business cards and notes without any pairing or prompts.

Certain printers and access points allow any device to use their services by default, much like unsecured Wi-Fi networks. Pairing algorithms are sometimes manufacturer-specific for transmitters and receivers used in applications such as music and entertainment.Bluetooth 2.1 has an optional "touch-to-pair" feature based on Near Field Communication (NFC). By simply bringing two devices into very close range (around 10cm/4in), pairing can securely take place without entering a passkey or manual configuration.

Air interface

The protocol operates in the license-free ISM band at 2.4-2.4835GHz. To avoid interfering with other protocols that use the 2.45GHz band, the Bluetooth protocol divides the band into 79channels (each 1MHz wide) and changes channels up to 1600 times per second. Implementations with versions 1.1 and 1.2 reach speeds of 723.1kbit/s. Version 2.0 implementations feature Bluetooth Enhanced Data Rate (EDR) and reach 2.1Mbit/s. Technically, version 2.0 devices have a higher power consumption, but the three times faster rate reduces the transmission times, effectively reducing power consumption to half that of 1.x devices (assuming equal traffic load).

Security Bluetooth implements confidentiality, authentication and key derivation with custom algorithms based on the SAFER+ block cipher. In Bluetooth, key generation is generally based on a Bluetooth PIN, which must be entered into both devices. This procedure might be modified if one of the devices has a fixed PIN, e.g. for headsets or similar devices with a restricted user interface. During pairing, an initialization key or master key is generated, using the E22 algorithm.[21] The E0 stream cipher is used for encrypting packets, granting confidentiality and is based on a shared cryptographic secret, namely a previously generated link key or master key. Those keys, used for subsequent encryption of data sent via the air interface, rely on the Bluetooth PIN, which has been entered into one or both devices.

In September 2008, the National Institute of Standards and Technology (NIST) published a Guide to Bluetooth Security that will serve as reference to organization on the security capabilities of Bluetooth and steps for securing Bluetooth technologies effectively. While Bluetooth has its benefits, it is susceptible to denial of service attacks, eavesdropping, man-in-the-middle attacks, message modification, and resource misappropriation. Users/organizations must evaluate their acceptable level of risk and incorporate security into the lifecycle of Bluetooth devices. To help mitigate risks, included in the NIST document are security checklists with guidelines and recommendations for creating and maintaining secure Bluetooth piconets, headsets, and smart card readers.

Bluejacking

Bluejacking is the sending of either a picture or a message from one user to an unsuspecting user through Bluetooth wireless technology. Common applications are short messages (e.g. "Youve just been bluejacked!"), advertisements (e.g. "Eat at Joes"), and business information. Bluejacking does not involve the removal or alteration of any data from the device.

The World Health Organization has acknowledged that electromagnetic fields (EMFs) are influencing the environment (but not people), and that some people are worried about possible effects.[1] In response to public concern, the World Health Organization established the International EMF Project in 1996 to assess the scientific evidence of possible health effects of EMF in the frequency range from 0 to 300 GHz. They have stated that although extensive research has been conducted into possible health effects of exposure to many parts of the frequency spectrum, all reviews conducted so far have indicated that exposures are below the limits recommended in the ICNIRP (1998) EMF guidelines, covering the full frequency range from 0-300 GHz, and do not produce any known adverse health effect

International guidelines on exposure levels to microwave frequency EMFs such as ICNIRP limit the power levels of wireless devices and it is uncommon for wireless devices to exceed the guidelines. These guidelines only take into account thermal effects, as nonthermal effects have not been conclusively demonstrated.[2] The official stance of the Health Protection Agency is that [T]here is no consistent evidence to date that WiFi and WLANs adversely affect the health of the general population. And also that ...it is a sensible precautionary approach...to keep the situation under ongoing review....

Wireless LAN EMF levels for WiFi devices are much lower than mobile phones, and there is less public concern about any suggested health issues for wireless LAN devices. Most wireless LAN equipment is designed to work within predefined standards. Wireless access points are also often in close proximity to humans, but the drop off in the already low power over distance is fast, following the inverse-square law. WiFi has been anecdotally linked to electromagnetic hypersensitivity, but no studies have researched this association to date.The HPA's position is that ...radio frequency (RF) exposures from WiFi are likely to be lower than those from mobile phones. It also saw ...no reason why schools and others should not use WiFi equipment.[3] In October 2007, the HPA launched a new systematic study into the effects of WiFi networks on behalf of the UK government, in order to calm fears that had appeared in the media in a recent period up to that time".[5] Dr Michael Clark, of the HPA, says published research on mobile phones and masts does not add up to an indictment of WiFi

IrDA vs Bluetooth If you examine the benefits of each technology, you can see that Bluetooth and IrDA are both critical to the marketplace. Each technology has advantages and drawbacks and neither can meet all users' needs. Bluetooth's ability to penetrate solid objects and its capability for maximum mobility within the piconet allows for data exchange applications that are very difficult or impossible with IrDA. For example, with Bluetooth a person could synchronize their phone with a PC without taking the phone out of their pocket or purse (this is not possible with IrDA). The omni-directional capability of Bluetooth allows synchronization to start when the phone is brought into range of the PC.

The Bluetooth standard defines the layers 1 and 2 of the OSI model. The application framework of Bluetooth is aimed to achieve interoperability with IrDA and WAP. In addition, a host of other applications will be able to use the Bluetooth technology and protocols.

SWAP vs Bluetooth

Currently SWAP has more installed base compared to Bluetooth but it is believed that Bluetooth is eventually going to prevail. Bluetooth is a technology to connect devices without cables. The intended use is to provide short-range connections between mobile devices and to the Internet via bridging devices to different networks (wired and wireless) that provide Internet capability. HomeRF SWAP is a wireless technology optimized for the home environment. Its primary use is to provide data networking and dial tones between devices such as PCs, cordless phones, Web Tablets and a broadband cable or DSL modem. Both technologies share the same frequency spectrum but do not interfere when operating in the same space.

Future

Bluetooth has a good future ahead because it meets a basic need of connectivity in close proximity, is the result of initiatives of nine leading communications and computer industry vendors including companies like 3-COM, Ericsson, Lucent, IBM, Intel, Microsoft, Nokia, Toshiba etc. Since the formation of the original group, more than 1800 manufacturers worldwide have joined the initiative worldwide. According to one market research report, Bluetooth technology is expected to be built into over 100 millions devices before the end of 2002. According to still another report from market research firm Cahners In-Stat Group, there will be over 670 million Bluetooth enabled devices worldwide by 2005.

As a result of success of WAP (Wireless Application Protocol), adoption of smart phones and handheld devices, Bluetooth will have tremendous effects on everyday life. Bluetooth is one of the key technologies that can make the mobile information society possible, blurring the boundaries between home, the office, and the outside world. The seamless connectivity promised by Bluetooth makes it possible to explore a range of interactive and highly transparent personalized services which were even difficult to dream of because of the complexity involved in making various devices talk to each other. Already many Bluetooth pilot products have rolled into the market backed by big vendors, which is a very healthy sign for the acceptance of the technology. The support for Bluetooth is not limited to companies developing Bluetooth enabled products only.

Bluetooth applications can have far reaching impacts on many other industries as well. Bluetooth technology adoption is expected to be widespread throughout the computer and telecommunications industry. Implementation of the Bluetooth technology is expected to grow the market for personal mobile devices and indirectly increase airtime usage for wireless data. Over the long term. manufacturers will also benefit from the ability to replace multiple connection ports with a single Bluetooth module, gaining economies at the production level. The Bluetooth SIG has defined favorable adoption terms, including open, royalty-free availability of the specification and is playing an important role in spreading the technology.

Tentative Timetable for Bluetooth Products and Adoption

1994Ericsson starts a project to study inexpensive interface between cellular phones and their accessoriesMar. 1998IBM, Intel, Nokia and Toshiba form Bluetooth Special Interest Group (SIG)Nov. 1999At CTIA, great excitement with over 1000 companies in the Bluetooth SIG. Conceptual framework - no products, no specificationsDec. 1999Version 1.0b of Bluetooth specifications releasedEnd 2000Limited product prototypes based on version 1.0b availableNovember 2000- ComdexLess enthusiasm than the previous year. A few products being demonstrated - Compaq released card. Some SDKs releasedApril 2001Version 1.1 of specifications released. Bluetooth radios in $30-40 range - More PC cards announced. Bluetooth server products in trade shows - No products for customers to buy.Mid 2002Products with integrated Bluetooth expected in the market - cost and prices of Bluetooth-enabled devices will still stay somewhat high. Downward spiral will at this time. .End 2002Most advanced 2.5G and 3G smart phones with Bluetooth; some PDAs with Bluetooth synchronization2003-2004Radio prices for vendors expected to go down to $5-10 - more widespread - Enterprise and home users may start buying Bluetooth-enabled devices. Limited replacement of fixed wiring with Bluetooth-enabled devices.Post 2005Bluetooth may start having major impact on short-distance networking and accessory connectivity

Bluetooth Versus 802.11b Wireless LANsThere is a debate going on regarding the merits of two technologies, rather three technologies - Wireless LANs, Bluetooth and wide area wireless networks. The protagonists (generally the vendors or consultants experienced in only one technology) extend the capabilities of their favorite technology against the other.

Bluetooth has lower distance range ( less than 30 feet) than 802.11b (up to 200 feet). Therefore, you would need many more access points to cover the same area of an office. Simple mathematics will show that you may need as many as 20-50 times the number of access points. Bluetooth has generally lower speed than that of 802.11b wireless LANs. Bluetooth components (chips and radios) and device adapters are cheaper than wireless LAN components and adapters. Bluetooth chips have lower power consumption - less drain on battery. Bluetooth is more appropriate and affordable technology for communication between smart phones and other accessories or between PDAs and information kiosks. Bluetooth is younger technology, and therefore is less mature. However, it has a huge following. Purely because of the potential and future expectation built by the Bluetooth vendors, there were over 2000 vendors signed up as members of Bluetooth forum There is a good developers following as well. Wireless LAN industry is smaller but more mature.

It is not fair to run comparisons between Bluetooth and WLAN regarding the number of chips being shipped or expected to be shipped for either technology. Because of its price and the type of products where it is going into, Bluetooth will soon surpass 802.11 chip shipments but dollar volume might still be smaller for some time. Ultimately, Bluetooth dollar volume is expected to catch up. Bluetooth will go beyond cable replacement in short distances between handheld devices and handheld devices and a kiosk or local server. It will meet the needs of connecting devices at the edge node of a network. Bluetooth and wireless LANs address different wireless connectivity requirements. Therefore, the two technologies need not and should not compete with each other.If Bluetooth community would not get offended, 802.11b is the big brother and Bluetooth is the younger brother. We also see emergence of technologies that bring the two together. Bluetooth access points like Red-M's 1050 connect Bluetooth devices to wireless LANs. See Multi Mode Access Point page on our site.

IEEE 802.11b & 802.11a

Bluetooth

Time Table

Standard in 1998, Products in 2000

Standard in 2000, products in 2001 and 2002

Frequency Band and bandwidth

IEEE 802.11b - 2.4 GHzIEEE 802.11a - 5GHHzIEEE 802.11g - 2.4

2.4 GHz

Speed

11 Mbps- 54 Mbps (Effective speed - half of rated speed)

1-2 Mbps (Effective speed - less than 50% rated speed)

Modulation Technique

Spread SpectrumOFDM

Distance Coverage

Up to 300 feet - 802.11bUp to 60 ft - 802.11a

Up to 30 feet now - efforts to increase coverage and speed

Number of access points required

every 200 feet - 802.11bEvery 50 feet - 802.11a

Every 30 feet - 25 to 30 times number of Bluetooth access points;

Maturity

More matured products

Less matured but progressing fast

Market Penetration

Quite widespread

Just starting in 2002

Interference with other devices

2.4 GHz band is polluted - significant interference here

2.4 GHz band is polluted - significant interference here

Interoperability

Current problems expected to be resolved in future

Problems now but expect resolution soon

Cost

Much more expensive than Bluetooth

Cost incremental in PDAs and phones - $50; However Bluetooth chips @

Coexistence of Bluetooth and WiFi

Several vendors ( Intersil, Silicon Wave and Mobilian) are building chips that will support both technologies in the same card. This will enable each of the two technologies to be used for what they are best suited to do. Chip set provider Intersil and Bluetooth radio maker Silicon Wave annunced reference design that allows simultaneous operation of two protocols. Both operate in the same band. The vendors seems to be addressing interference issues between the two technologies. Blue802 technology uses a time-slicing technique in which two protocols switch back and forth fast enough to give the appearance of simultaneous operation.

CONCLUSIONBluetooth technology is a wireless protocol that connects electronic devices while they are in close vicinity of one another. Instead of creating a local-area network (LAN) or a wide-area network (WAN), Bluetooth creates a personal-area network (PAN) just for you. Cell phones, for example, can be paired with wireless Bluetooth headsets. When used in tandem with a Bluetooth-enabled cell phone and successfully paired, you can leave your cell phone in your pocket and perform most of your mobile phones functions using your in-ear Bluetooth headset.In addition to being paired with cell phones, short-range Bluetooth technology is also compatible with personal computers, laptops, printers, GPS receivers, digital cameras, telephones, video game consoles and more for various practical functions. And no doubt the future of the Bluetooth is very bright and secure, due its unique technology.

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