Bluetooth

Teclado bluetooth enlazado a uncomputador de bolsillo.

Unauricularparatelfono mvilpor Bluetooth.Bluetoothes una especificacin industrial paraRedes Inalmbricas de rea Personal(WPAN) que posibilita la transmisin de voz ydatosentre diferentes dispositivos mediante un enlace porradiofrecuenciaen labanda ISMde los 2,4GHz. Los principales objetivos que se pretenden conseguir con esta norma son: Facilitar las comunicaciones entre equipos mviles. Eliminar los cables y conectores entre stos. Ofrecer la posibilidad de crear pequeasredes inalmbricasy facilitar la sincronizacin de datos entre equipos personales.Los dispositivos que con mayor frecuencia utilizan esta tecnologa pertenecen a sectores de lastelecomunicacionesy lainformticapersonal, comoPDA,telfonos mviles,computadoras porttiles,ordenadores personales,impresorasocmaras digitales.ndice[ocultar] 1Nombre y logo 2Usos y aplicaciones 2.1Perfiles Bluetooth 2.2Lista de aplicaciones 3Especificaciones y novedades 3.1Bluetooth v1.0 y v1.0b 3.2Bluetooth v1.1 (2002) 3.3Bluetooth v1.2 (2003) 3.4Bluetooth v2.0 + EDR (2004) 3.5Bluetooth v2.1 + EDR (2007) 3.6Bluetooth v3.0 + HS (2009) 3.7Bluetooth v4.0 (2010) 4Informacin tcnica 4.1Arquitectura hardware 5Dispositivo de Radio Bluetooth Genrico. 5.1Usos de Bluetooth 5.2El SIG de Bluetooth 5.3Bluetooth contra Wi-Fi 5.3.1Wi-Fi 5.3.2Wi-Fi Direct 6Vase tambin 7Referencias 8Enlaces externosNombre y logo[editareditar cdigo]El nombre procede del reydansynoruegoHarald Bltand, cuya traduccin al ingls esHarald Bluetooth, conocido por unificar las tribus noruegas, suecas y danesas y por convertirlos al cristianismo. La idea de este nombre fue propuesto por Jim Kardach que desarroll un sistema que permitira a los telfonos mviles comunicarse con los ordenadores y unificar la comunicacin de los sistemas digitales.El logo de Bluetooth son lasrunasde las iniciales del nombre y el apellido.la (Hagall) y la(Berkana).Usos y aplicaciones[editareditar cdigo]

Apple Mighty Mousecon tecnologa Bluetooth.Se denomina Bluetooth alprotocolo de comunicacionesdiseado especialmente para dispositivos de bajo consumo, que requieren corto alcance de emisin y basados entransceptoresde bajo costo.Los dispositivos que incorporan este protocolo pueden comunicarse entre ellos cuando se encuentran dentro de su alcance. Las comunicaciones se realizan porradiofrecuenciade forma que los dispositivos no tienen que estar alineados y pueden incluso estar en habitaciones separadas si la potencia de transmisin es suficiente. Estos dispositivos se clasifican como "Clase 1", "Clase 2" o "Clase 3" en referencia a su potencia de transmisin, siendo totalmente compatibles los dispositivos de una caja de ordenadorClasePotencia mxima permitida(mW)Potencia mxima permitida(dBm)Alcance(aproximado)

Clase 1100mW20dBm~30 metros

Clase 22.5mW4dBm~10-5 metros

Clase 31mW0dBm~1 metro

En la mayora de los casos, la cobertura efectiva de un dispositivo de clase 2 se extiende cuando se conecta a un transceptor de clase 1. Esto es as gracias a la mayor sensibilidad y potencia de transmisin del dispositivo de clase 1, es decir, la mayor potencia de transmisin del dispositivo de clase 1 permite que la seal llegue con energa suficiente hasta el de clase 2. Por otra parte la mayor sensibilidad del dispositivo de clase 1 permite recibir la seal del otro pese a ser ms dbil.Los dispositivos con Bluetooth tambin pueden clasificarse segn su ancho de banda:VersinAncho de banda

Versin 1.21Mbit/s

Versin 2.0 + EDR3Mbit/s

Versin 3.0 + HS24Mbit/s

Versin 4.024Mbit/s

Perfiles Bluetooth[editareditar cdigo]Artculo principal:Perfil BluetoothPara utilizar Bluetooth, un dispositivo debe implementar alguno de los perfiles Bluetooth. Estos definen el uso del canal Bluetooth, as como canalizar al dispositivo que se quiere vincular.Lista de aplicaciones[editareditar cdigo]

Manos libres para eliPhonecon tecnologa Bluetooth. Conexin sin cables vaOBEX. Transferencia de fichas de contactos, citas y recordatorios entre dispositivos vaOBEX. Reemplazo de la tradicional comunicacin por cable entre equiposGPSy equipamiento mdico. Controles remotos (tradicionalmente dominado por el infrarrojo). Enviar pequeas publicidades desde anunciantes a dispositivos con Bluetooth. Un negocio podra enviar publicidad a telfonos mviles cuyo Bluetooth (los que lo posean) estuviera activado al pasar cerca. Las consolasSonyPlayStation 3,MicrosoftXbox360yWiiincorporan Bluetooth, lo que les permite utilizar mandos inalmbricos, aunque los mandos originales de laWiifuncionan mezclando la tecnologa de infrarrojos y Bluetooth. Enlace inalmbrico entre sistemas de audio y los altavoces (o altoparlantes) correspondientes.Especificaciones y novedades[editareditar cdigo]La utilidad Bluetooth fue desarrollada como un reemplazo del cable en 1994 por Jaap Haartsen y Mattisson Sven, que estaban trabajando para Ericsson en Lund, Suecia.1La utilidad se basa en la tecnologa de saltos de frecuencia de amplio espectro.Las prestaciones fueron publicadas por el Bluetooth Special Interest Group (SIG). El SIG las anunci formalmente el 20 de mayo de 1998. Hoy cuenta con una membresa de ms de 20,000 empresas en todo el mundo. Fue creado por Ericsson, IBM, Intel, Toshiba y Nokia, y posteriormente se sumaron muchas otras compaas. Todas las versiones de los estndares de Bluetooth estn diseadas para la compatibilidad hacia abajo, que permite que el ltimo estndar cubra todas las versiones anteriores.Bluetooth v1.0 y v1.0b[editareditar cdigo]Las versiones 1.0 y 1.0b han tenido muchos problemas, y los fabricantes tenan dificultades para hacer sus productos interoperables. Las versiones 1.0 y 1.0b incluyen en hardware de forma obligatoria la direccin del dispositivo Bluetooth (BD_ADDR) en la transmisin (el anonimato se hace imposible a nivel de protocolo), lo que fue un gran revs para algunos servicios previstos para su uso en entornos Bluetooth.Bluetooth v1.1 (2002)[editareditar cdigo] Ratificado como estndar IEEE 802.15.1-20022 Se corrigieron muchos errores en las especificaciones 1.0b. Aadido soporte para canales no cifrados. Indicador de seal recibida (RSSI).Bluetooth v1.2 (2003)[editareditar cdigo]Esta versin es compatible con USB 1.1 y las principales mejoras son las siguientes: Una conexin ms rpida y Discovery (deteccin de otros dispositivos bluetooth). Salto de frecuencia adaptable de espectro ampliado (AFH), que mejora la resistencia a las interferencias de radio frecuencia, evitando el uso de las frecuencias de lleno en la secuencia de saltos. Mayor velocidad de transmisin en la prctica, de hasta 721 kbit/s,3que en v1.1. Conexiones Sincrnicas extendidas (ESCO), que mejoran la calidad de la voz de los enlaces de audio al permitir la retransmisin de paquetes corruptos, y, opcionalmente, puede aumentar la latencia de audio para proporcionar un mejor soporte para la transferencia de datos simultnea. Host Controller Interface (HCI) el apoyo a tres hilos UART. Ratificado como estndar IEEE 802.15.1-20054 Introdujo el control de flujo y los modos de retransmisin de L2CAP.Bluetooth v2.0 + EDR (2004)[editareditar cdigo]Esta versin de la especificacin principal Bluetooth fue lanzado en 2004 y es compatible con la versin anterior 1.2. La principal diferencia es la introduccin de una velocidad de datos mejorada (EDR "Enhanced Data Rate" "mayor velocidad de transmisin de datos") para acelerar la transferencia de datos. La tasa nominal de EDR es de 3 Mbit / s, aunque la tasa de transferencia de datos prctica es de 2,1 Mbit / s.3EDR utiliza una combinacin de GFSK y Phase Shift Keying modulacin (PSK) con dos variantes, /4-DQPSK y 8DPSK.5EDR puede proporcionar un menor consumo de energa a travs de un ciclo de trabajo reducido.La especificacin se publica como "Bluetooth v2.0 + EDR", lo que implica que EDR es una caracterstica opcional. Aparte de EDR, hay otras pequeas mejoras en la especificacin 2.0, y los productos pueden reclamar el cumplimiento de "Bluetooth v2.0" sin el apoyo de la mayor tasa de datos. Por lo menos un dispositivo de estados comerciales "sin EDR Bluetooth v2.0" en su ficha tcnica.6Bluetooth v2.1 + EDR (2007)[editareditar cdigo]Bluetooth Core Version especificacin 2.1 + EDR es totalmente compatible con 1.2, y fue adoptada por el Bluetooth SIG ( Bluetooth Special Interest Group) el 26 de julio de 2007.5La funcin de titular de la 2.1 es Secure Simple Pairing (SSP): se mejora la experiencia de emparejamiento de dispositivos Bluetooth, mientras que el aumento del uso y la fuerza de seguridad. Vea la seccin de enlace de abajo para ms detalles.72.1 permite a otras mejoras, incluida la "respuesta amplia investigacin" (EIR), que proporciona ms informacin durante el procedimiento de investigacin para permitir un mejor filtrado de los dispositivos antes de la conexin, y oler subrating, lo que reduce el consumo de energa en modo de bajo consumo.Bluetooth v3.0 + HS (2009)[editareditar cdigo]La versin 3.0 + HS de la especificacin principal Bluetooth5fue aprobado por el Bluetooth SIG el 21 de abril de 2009. Bluetooth 3.0 + HS soporta velocidades de transferencia de datos terica de hasta 24 Mbit / entre s, aunque no a travs del enlace Bluetooth propiamente dicho. La conexin Bluetooth nativa se utiliza para la negociacin y el establecimiento mientras que el trfico de datos de alta velocidad se realiza mediante un enlace 802.11. Su principal novedad es AMP (Alternate MAC / PHY), la adicin de 802,11 como transporte de alta velocidad. Estaban inicialmente previstas dos tecnologas para incorporar en AMP:. 802.11 y UWB, pero finalmente UWB no se encuentra en la especificacin.8La incorporacin de la transmisin a alta velocidad no es obligatoria en la especificacin y por lo tanto, los dispositivos marcados con "+ HS" incorporan el enlace 802.11 de alta velocidad de transferencia de datos. Un dispositivo Bluetooth 3.0, sin el sufijo "+ HS" no apoyar a alta velocidad, y slo admite una caracterstica introducida en Bluetooth 3.0 + HS (o en CSA1).9Alternativa MAC / PHYPermite el uso de alternativas MAC y PHY para el transporte de datos de perfil Bluetooth. La radio Bluetooth est siendo utilizada para la deteccin de dispositivos, la conexin inicial y configuracin del perfil, sin embargo, cuando deben enviarse grandes cantidades de datos, se utiliza PHY MAC 802.11 (por lo general asociados con Wi-Fi) para transportar los datos. Esto significa que el modo de baja energa de la conexin Bluetooth se utiliza cuando el sistema est inactivo, y la radio 802.11 cuando se necesitan enviar grandes cantidades de datos.Unicast de datos sin conexinDatos de los permisos de servicio para ser enviado sin establecer un canal L2CAP explcito. Est diseado para su uso en aplicaciones que requieren baja latencia entre la accin del usuario y la reconexin / transmisin de datos. Esto slo es adecuado para pequeas cantidades de datos. Control de energa mejorada Actualizacin de la funcin de control de potencia para eliminar el control de lazo abierto de energa, y tambin para aclarar las ambigedades en el control de energa presentado por los esquemas de modulacin nuevo aadido para EDR. Control de potencia mejorada elimina las ambigedades mediante la especificacin de la conducta que se espera. Esta caracterstica tambin aade control de potencia de bucle cerrado, es decir, RSSI filtrado puede empezar como se recibe la respuesta. Adems, un "ir directamente a la mxima potencia" solicitud ha sido introducido. Con ello se espera abordar el tema auriculares prdida de enlace normalmente se observa cuando un usuario pone su telfono en un bolsillo en el lado opuesto a los auriculares. La alta velocidad (AMP) caracterstica de la versin 3.0 de Bluetooth se basa en 802,11, pero el mecanismo de AMP fue diseado para ser utilizado con otras radios tambin. Fue pensado originalmente para UWB, pero la WiMedia Alliance, el organismo responsable por el sabor de la UWB destinado a Bluetooth, anunciado en marzo de 2009 que fue la disolucin. El 16 de marzo de 2009, la WiMedia Alliance anunci que iba a entrar en acuerdos de transferencia de tecnologa para la WiMedia Ultra-Wideband (UWB) especificaciones. WiMedia ha transferido todas las especificaciones actuales y futuros, incluido el trabajo sobre el futuro de alta velocidad y las implementaciones de energa optimizado, el Bluetooth Special Interest Group (SIG), Wireless USB Promoter Group y el Foro de Implementadores USB. Despus de la finalizacin con xito de la transferencia de tecnologa, marketing y relacionados con cuestiones administrativas, la WiMedia Alliance dejar de operar.1011121314En octubre de 2009, el Bluetooth especial de desarrollo del Grupo de Inters en suspensin de UWB como parte de la alternativa MAC / PHY, v3.0 + Bluetooth solucin HS. Un nmero pequeo, pero significativo, de antiguos miembros de WiMedia no tena y no iba a firmar con los acuerdos necesarios para la transferencia de propiedad intelectual. El SIG de Bluetooth se encuentra ahora en el proceso de evaluar otras opciones para su plan de accin a largo plazo.15Bluetooth v4.0 (2010)El SIG de Bluetooth ha completado la especificacin del Ncleo de Bluetooth en su versin 4.0, que incluye Bluetooth clsico, Bluetooth de alta velocidad y protocolos Bluetooth de bajo consumo. Bluetooth de alta velocidad se basa en Wi-Fi, y Bluetooth clsico consta de protocolos Bluetooth preexistentes. Esta versin ha sido adoptada el 30 de junio de 2010. Bluetooth de baja energa (Bluetooth Low Energyo BLE) es un subconjunto de Bluetooth v4.0 con una pila de protocolo completamente nueva para desarrollar rpidamente enlaces sencillos. Como alternativa a los protocolos estndar de Bluetooth que se introdujeron en Bluetooth v1.0 a v4.0 est dirigido a aplicaciones de muy baja potencia alimentados con una pila botn. Diseos de chips permiten dos tipos de implementacin, de modo dual, de modo nico y versiones anteriores mejoradas. En implementaciones de modo nico slo se incluye la pila de protocolo de baja energa. CSR16,Nordic Semiconductor17yTexas Instruments18han dado a conocer solo las soluciones Bluetooth modo de baja energa. En implementaciones de modo dual, la funcionalidad de Bluetooth de bajo consumo est integrada en un controlador Bluetooth clsico existente. En la actualidad (2011-03) los siguientes fabricantes de semiconductores han anunciado la disponibilidad de chips que cumplen esta norma: Atheros, CSR, Broadcom1920yTexas Instruments. La arquitectura resultante comparte la radio y funcionalidades del Bluetooth clsico, resultando en un incremento de coste negligible comparado con el Bluetooth clsico.El 12 de junio de 2007, Nokia y Bluetooth SIG anunciaron que Wibree formar parte de la especificacin Bluetooth, como una tecnologa de muy bajo consumo Bluetooth.21El 17 de diciembre de 2009, el Bluetooth SIG adopt la tecnologa Bluetooth de bajo consumo como el rasgo distintivo de la versin 4.0.22Los nombres provisionales Wibree y Bluetooth ULP (Ultra Low Power) fueron abandonados y el nombre BLE se utiliz durante un tiempo. A finales de 2011, los nuevos logotipos "Smart Bluetooth Ready" para los anfitriones y "Smart Bluetooth" para los sensores se present como la cara pblica general de BLE.23Informacin tcnica[editareditar cdigo]Artculo principal:Bluetooth (especificacin)La especificacin de Bluetooth define un canal de comunicacin a un mximo 720 kbit/s (1 Mbit/s de capacidad bruta) con rango ptimo de 10m(opcionalmente 100 m con repetidores).Opera en la frecuencia de radio de 2,4 a 2,48 GHz con amplio espectro y saltos de frecuencia con posibilidad de transmitir enFull Duplexcon un mximo de 1600 saltos porsegundo. Los saltos de frecuencia se dan entre un total de 79 frecuencias con intervalos de 1 MHz; esto permite dar seguridad y robustez.La potencia de salida para transmitir a una distancia mxima de 10 metros es de 0dBm(1 mW), mientras que la versin de largo alcance transmite entre 20 y 30 dBm (entre 100 mW y 1 W).Para lograr alcanzar el objetivo de bajo consumo y bajo costo se ide una solucin que se puede implementar en un solochiputilizando circuitosCMOS. De esta manera, se logr crear una solucin de 99 mm y que consume aproximadamente 97% menos energa que un telfono celular comn.El protocolo debanda base(canales simples por lnea) combina conmutacin de circuitos y paquetes. Para asegurar que los paquetes no lleguen fuera de orden, los slots pueden ser reservados por paquetes sncronos, empleando un salto diferente de seal para cada paquete.La conmutacin de circuitos puede ser asncrona o sncrona. Cada canal permite soportar tres canales de datos sncronos (voz) o un canal de datos sncrono y otro asncrono.Cada canal de voz puede soportar una tasa de transferencia de 64 kbit/s en cada sentido, la cual es suficiente para la transmisin de voz.Un canal asncrono puede transmitir como mucho 721 kbit/s en una direccin y 56 kbit/s en la direccin opuesta. Sin embargo, una conexin sncrona puede soportar 432,6 kbit/s en ambas direcciones si el enlace es simtrico.Arquitectura hardware[editareditar cdigo]El hardware que compone el dispositivo Bluetooth est compuesto por dos partes: un dispositivo de radio, encargado de modular y transmitir la seal. un controlador digital, compuesto por unaCPU, un procesador de seales digitales (DSP - Digital Signal Processor) llamado Link Controller (o controlador de Enlace) y de las interfaces con el dispositivo anfitrin.El LC o Link Controller se encarga del procesamiento de la banda base y del manejo de los protocolos ARQ y FEC de la capa fsica; adems, se encarga de las funciones de transferencia tanto asncrona como sncrona, la codificacin de audio y el cifrado de datos.La CPU del dispositivo se encarga de las instrucciones relacionadas con Bluetooth en el dispositivo anfitrin, para as simplificar su operacin.Para ello, sobre la CPU corre un software denominado Link Manager cuya funcin es la de comunicarse con otros dispositivos por medio del protocolo LMP.Dispositivo de Radio Bluetooth Genrico.[editareditar cdigo]Entre las tareas realizadas por el LC y el Link Manager, destacan las siguientes: Envo y Recepcin de Datos. Paginacin y Peticiones. Establecimiendo de conexiones. Autenticacin. Negociacin y establecimiento de tipos de enlace. Establecimiento del tipo de cuerpo de cada paquete. Establecer el dispositivo en modo sniff o hold: El primero, sniff, significa olfatear, pero en castellano y en informtica se traduce por escuchar (el medio): en este caso es la frecuencia o frecuencias en la que est funcionando el dispositivo. As, cualquier paquete de datos enviado en esa frecuencia ser "ledo" por el dispositivo, aunque no vaya dirigido a l. Leer todos los datos que se enven en esa frecuencia por cualquier otro dispositivo Bluetooth, es lo que se denomina rastreo de paquetes.Una tcnica parecida pero a nivel de frecuencias es la que se utiliza para detectar redes wi-fi, generalmente para encontrar redes abiertas (sin contrasea), al escanear todas las frecuencias se obtiene informacin de cada frecuencia o canal de las redes wi-fi disponibles.Hold por su parte significa mantener, retener; esto quiere decir que el dispositivo se mantendr en esa frecuencia aunque no emita ni reciba nada, manteniendo esa frecuencia siempre disponible aunque otros dispositivos la utilicen.Usos de Bluetooth[editareditar cdigo]Bluetooth se utiliza principalmente en un gran nmero de productos tales como telfonos, impresoras,mdemsy auriculares. Su uso es adecuado cuando puede haber dos o ms dispositivos en un rea reducida sin grandes necesidades de ancho de banda. Su uso ms comn est integrado en telfonos y PDA, bien por medio de unos auriculares Bluetooth o en transferencia de ficheros. adems se puede realizar y confeccionar enlaces o vincular distintos dispositivos entre s.Bluetooth simplifica el descubrimiento y configuracin de los dispositivos, ya que estos pueden indicar a otros los servicios que ofrecen, lo que permite establecer la conexin de forma rpida (slo la conexin, no la velocidad de transmisin).El SIG de Bluetooth[editareditar cdigo]vaseBluetooth SIG.Puede compararse la eficiencia de varios protocolos de transmisin inalmbrica, como Bluetooth y Wi-Fi, por medio de lacapacidad espacial(bits por segundo y metro cuadrado).Bluetooth contra Wi-Fi[editareditar cdigo]Bluetooth yWi-Ficubren necesidades distintas en los entornos domsticos actuales: desde la creacin de redes y las labores de impresin a la transferencia de ficheros entrePDAy ordenadores personales. Ambas tecnologas operan en las bandas de frecuencia no reguladas (banda ISM).Wi-Fi[editareditar cdigo]Wi-Fies similar a la red Ethernet tradicional y como tal el establecimiento de comunicacin necesita una configuracin previa. Utiliza el mismo espectro de frecuencia que Bluetooth con una potencia de salida mayor que lleva a conexiones ms slidas. A veces se denomina a Wi-Fi la Ethernet sin cables. Aunque esta descripcin no es muy precisa, da una idea de sus ventajas e inconvenientes en comparacin a otras alternativas. Se adecua mejor para redes de propsito general: permite conexiones ms rpidas, un rango de distancias mayor y mejores mecanismos de seguridad.Wi-Fi Direct[editareditar cdigo]Wi-Fi Directes un programa de certificacin que permite que varios dispositivosWi-Fise conecten entre s sin necesidad de unpunto de accesointermedio.Cuando un dispositivo ingresa al rango del anfitrin Wi-Fi Direct, ste se puede conectar usando el protocolo ad hoc existente, y luego recolecta informacin de configuracin usando una transferencia del mismo tipo de la de Protected Setup. La conexin y configuracin se simplifican de tal forma que algunos sugieren que esto podra reemplazar al Bluetooth en algunas situaciones.

BluetoothFrom Wikipedia, the free encyclopediaThis article is about a wireless technology standard. For the medieval King of Denmark, seeHarald Bluetooth.Bluetooth

Developed byBluetooth Special Interest Group

IndustryMobilepersonal area networks

Compatible hardwareMobile phones,Personal computers,Laptop computers

Physical rangeUp to 50 metres[1]

Bluetoothis awirelesstechnology standard for exchanging data over short distances (using short-wavelength microwavetransmissionsin theISMband from 24002480MHz[2]) from fixed and mobile devices, buildingpersonal area networks(PANs). Invented by telecom vendorEricssonin 1994,[3]it was originally conceived as a wireless alternative toRS-232data cables. It can connect several devices, overcoming problems of synchronization.Bluetooth is managed by theBluetooth Special Interest Group, which has more than 19,000 member companies in the areas of telecommunication, computing, networking, and consumer electronics.[4]Bluetooth was standardized asIEEE 802.15.1, but the standard is no longer maintained. The SIG oversees the development of the specification, manages the qualification program, and protects the trademarks.[5]To be marketed as a Bluetooth device, it must bequalifiedto standards defined by the SIG.[6]A network ofpatentsis required to implement the technology, which is licensed only for that qualifying device.Contents[hide] 1Name and logo 2Implementation 2.1Communication and connection 3Uses 3.1Bluetooth profiles 3.2List of applications 3.3Bluetooth vs. Wi-Fi (IEEE 802.11) 3.4Devices 4Computer requirements 4.1Operating system implementation 5Specifications and features 5.1Bluetooth v1.0 and v1.0B 5.2Bluetooth v1.1 5.3Bluetooth v1.2 5.4Bluetooth v2.0 + EDR 5.5Bluetooth v2.1 + EDR 5.6Bluetooth v3.0 + HS 5.6.1Ultra-wideband 5.7Bluetooth Smart (v4.0) 6Technical information 6.1Bluetooth protocol stack 6.1.1LMP 6.1.2AVRCP 6.1.3L2CAP 6.1.4SDP 6.1.5RFCOMM 6.1.6BNEP 6.1.7AVCTP 6.1.8AVDTP 6.1.9TCS 6.1.10Adopted protocols 6.2Baseband error correction 6.3Setting up connections 6.4Pairing and bonding 6.4.1Motivation 6.4.2Implementation 6.4.3Pairing mechanisms 6.4.4Security concerns 6.5Air interface 7Security 7.1Overview 7.2Bluejacking 7.3History of security concerns 7.3.120012004 7.3.22005 7.3.32006 7.3.42007 8Health concerns 9Bluetooth Innovation World Cup marketing initiative 10See also 11References 12External linksName and logo[edit]

Bluetooth logoThe word "Bluetooth" is ananglicizedversion of the ScandinavianBltand/Bltann, (Old Norsebltnn) theepithetof the tenth-century kingHarald Bluetoothwho united dissonant Danish tribes into a single kingdom, according to legend, introducing Christianity as well. The idea of this name was proposed in1997byJim Kardachwho developed a system that would allow mobile phones to communicate with computers (at the time he was readingFrans Gunnar Bengtsson's historical novelThe Long Shipsabout Vikings and kingHarald Bluetooth).[7][8]The implication is that Bluetooth does the same with communications protocols, uniting them into one universal standard.[9][10][11]The Bluetooth logo is abind runemerging theYounger Futharkrunes(Hagall) () and(Bjarkan) (), Harald's initials.Implementation[edit]Bluetooth operates in the range of 24002483.5MHz (including guard bands). This is in the globally unlicensed (but not unregulated) Industrial, Scientific and Medical (ISM) 2.4GHz short-range radio frequency band. Bluetooth uses a radio technology calledfrequency-hopping spread spectrum. The transmitted data is divided into packets and each packet is transmitted on one of the 79 designated Bluetooth channels. Each channel has a bandwidth of 1MHz. The first channel starts at 2402MHz and continues up to 2480MHz in 1MHz steps. It usually performs 1600hops per second, withAdaptive Frequency-Hopping(AFH) enabled.[12]OriginallyGaussian frequency-shift keying(GFSK) modulation was the only modulation scheme available; subsequently, since the introduction of Bluetooth 2.0+EDR, /4-DQPSKand 8DPSK modulation may also be used between compatible devices. Devices functioning with GFSK are said to be operating in basic rate (BR) mode where an instantaneousdata rateof 1Mbit/sis possible. The term Enhanced Data Rate (EDR) is used to describe /4-DPSK and 8DPSK schemes, each giving 2 and 3Mbit/s respectively. The combination of these (BR and EDR) modes in Bluetooth radio technology is classified as a "BR/EDR radio".Bluetooth is apacket-based protocolwith amaster-slave structure. One master may communicate with up to 7slaves in apiconet; all devices share the master's clock. Packet exchange is based on the basic clock, defined by the master, which ticks at 312.5s intervals. Two clock ticks make up a slot of 625s; two slots make up a slot pair of 1250s. In the simple case of single-slot packets the master transmits in even slots and receives in odd slots; the slave, conversely, receives in even slots and transmits in odd slots. Packets may be 1, 3 or 5 slots long but in all cases the master transmit will begin in even slots and the slave transmit in odd slots.Communication and connection[edit]A master Bluetooth device can communicate with a maximum of seven devices in apiconet(an ad-hoc computer network using Bluetooth technology), though not all devices reach this maximum. The devices can switch roles, by agreement, and the slave can become the master (for example, a headset initiating a connection to a phone will necessarily begin as master, as initiator of the connection; but may subsequently prefer to be slave).The Bluetooth Core Specification provides for the connection of two or more piconets to form ascatternet, in which certain devices simultaneously play the master role in one piconet and the slave role in another.At any given time, data can be transferred between the master and one other device (except for the little-used broadcast mode[citation needed]). The master chooses which slave device to address; typically, it switches rapidly from one device to another in around-robinfashion. Since it is the master that chooses which slave to address, whereas a slave is (in theory) supposed to listen in each receive slot, being a master is a lighter burden than being a slave. Being a master of seven slaves is possible; being a slave of more than one master is difficult.[citation needed]The specification is vague as to required behavior in scatternets.Many USB Bluetoothadaptersor "dongles" are available, some of which also include anIrDAadapter.Uses[edit]Bluetooth is a standard wire-replacement communications protocol primarily designed for low power consumption, with a short range (power-class-dependent, but effective ranges vary in practice; see table below) based on low-costtransceivermicrochipsin each device.[13]Because the devices use a radio (broadcast) communications system, they do not have to be in visual line of sight of each other, however aquasi opticalwireless path must be viable.[4]ClassMaximum permitted powerTyp. Range(m)

(mW)(dBm)

Class 110020~100[14]

Class 22.54~10[14]

Class 310~1[14]

The effective range varies due to propagation conditions, material coverage, production sample variations, antenna configurations and battery conditions. Most Bluetooth applications are in indoor conditions, where attenuation of walls and signal fading due to signal reflections will cause the range to be far lower than the specified line-of-sight ranges of the Bluetooth products. Most Bluetooth applications are battery powered Class2 devices, with little difference in range whether the other end of the link is a Class1 or Class2 device as the lower powered device tends to set the range limit. In some cases the effective range of the data link can be extended when a Class2 devices is connecting to a Class1 transceiver with both higher sensitivity and transmission power than a typical Class2 device.[15]Mostly however the Class1 devices have a similar sensitivity to Class2 devices. Connecting two Class1 devices with both high sensitivity and high power can allow ranges far in excess of the typical 100m, depending on the throughput required by the application. Some such devices allow open field ranges of up to 1km and beyond between two similar devices without exceeding legal emission limits.[16][17][18]VersionData rateMaximum application throughput

Version 1.21Mbit/s>80 kbit/s

Version 2.0 + EDR3 Mbit/s>80 kbit/s

Version 3.0 + HS24 Mbit/sSeeVersion 3.0+HS.

Version 4.024 Mbit/sSeeVersion 4.0LE.

While the Bluetooth Core Specification does mandate minima for range, the range of the technology is application specific and is not limited. Manufacturers may tune their implementations to the range needed for individual use cases.Bluetooth profiles[edit]Main article:Bluetooth profile[19]To use Bluetooth wireless technology, a device has to be able to interpret certain Bluetooth profiles, which are definitions of possible applications and specify general behaviors that Bluetooth enabled devices use to communicate with other Bluetooth devices. These profiles include settings to parametrize and to control the communication from start. Adherence to profiles saves the time for transmitting the parameters anew before the bi-directional link becomes effective. There are a wide range of Bluetooth profiles that describe many different types of applications or use cases for devices.[20]List of applications[edit]

A typical Bluetooth mobile phoneheadset. Wireless control of and communication between a mobile phone and ahandsfreeheadset. This was one of the earliest applications to become popular. Wireless control of and communication between a mobile phone and a Bluetooth compatible car stereo system. WirelessBluetooth headsetandIntercom. Idiomatically, a headset is sometimes called "a Bluetooth". Wireless networking between PCs in a confined space and where little bandwidth is required. Wireless communication with PC input and output devices, the most common being themouse,keyboardandprinter. Transfer of files, contact details, calendar appointments, and reminders between devices withOBEX. Replacement of previous wiredRS-232serial communications in test equipment,GPS receivers, medical equipment, bar code scanners, and traffic control devices. For controls whereinfraredwas often used. For low bandwidth applications where higherUSBbandwidth is not required and cable-free connection desired. Sending small advertisements from Bluetooth-enabled advertising hoardings to other, discoverable, Bluetooth devices.[21] Wireless bridge between two Industrial Ethernet (e.g.,PROFINET) networks. Threeseventhandeighth generationgame consoles,Nintendo'sWii.[22]andSony'sPlayStation 3, use Bluetooth for their respective wireless controllers. Dial-up internet access on personal computers or PDAs using a data-capable mobile phone as a wireless modem. Short range transmission of health sensor data from medical devices to mobile phone,set-top boxor dedicatedtelehealthdevices.[23] Allowing aDECTphone to ring and answer calls on behalf of a nearby mobile phone. Real-time location systems (RTLS), are used to track and identify the location of objects in real-time using Nodes or tags attached to, or embedded in the objects tracked, and Readers that receive and process the wireless signals from these tags to determine their locations.[24] Personal security application on mobile phones for prevention of theft or loss of items. The protected item has a Bluetooth marker (e.g. a tag) that is in constant communication with the phone. If the connection is broken (the marker is out of range of the phone) then an alarm is raised. This can also be used as a man overboard alarm. A product using this technology has been available since 2009.[25] Calgary, Alberta, Canada's Roads Traffic division uses data collected from travelers' Bluetooth devices to predict travel times and road congestion for motorists.[26]Bluetooth vs. Wi-Fi (IEEE 802.11)[edit]Bluetooth andWi-Fi(the brand name for products usingIEEE 802.11standards) have some similar applications: setting up networks, printing, or transferring files. Wi-Fi is intended as a replacement for high speed cabling for generallocal area networkaccess in work areas. This category of applications is sometimes calledwireless local area networks(WLAN). Bluetooth was intended for portable equipment and its applications. The category of applications is outlined as the wirelesspersonal area network(WPAN). Bluetooth is a replacement for cabling in a variety of personally carried applications in any setting and also works for fixed location applications such as smart energy functionality in the home (thermostats, etc.).Wi-Fi and Bluetooth are to some extent complementary in their applications and usage. Wi-Fi is usually access point-centered, with an asymmetrical client-server connection with all traffic routed through the access point, while Bluetooth is usually symmetrical, between two Bluetooth devices. Bluetooth serves well in simple applications where two devices need to connect with minimal configuration like a button press, as in headsets and remote controls, while Wi-Fi suits better in applications where some degree of client configuration is possible and high speeds are required, especially for network access through an access node. However, Bluetooth access points do exist and ad-hoc connections are possible with Wi-Fi though not as simply as with Bluetooth.Wi-Fi Directwas recently developed to add a more Bluetooth-like ad-hoc functionality to Wi-Fi.Devices[edit]

A BluetoothUSBdongle with a 100m range.Bluetooth exists in many products, such as telephones, tablets, media players,Lego Mindstorms NXT,PlayStation 3,PS Vita, the NintendoWii, and some high definitionheadsets,modems, and watches.[27]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 protocols simplify the discovery and setup of services between devices.[28]Bluetooth devices can advertise all of the services they provide.[29]This makes using services easier because more of the security, network address and permission configuration can be automated than with many other network types.[28]Computer requirements[edit]

A typical BluetoothUSBdongle.

An internal notebook Bluetooth card (14364mm).A personal computer that does not have embedded Bluetooth can be used with a Bluetooth adapter that will enable the PC to communicate with other Bluetooth devices. While somedesktop computersand most recent laptops come with a built-in Bluetooth radio, others will require an external one in the form of adongle.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 implementation[edit]For more details on this topic, seeBluetooth stack.Appleproducts have worked with Bluetooth sinceMacOSX v10.2which was released in 2002.[30]ForMicrosoftplatforms,Windows XP Service Pack 2and SP3 releases work natively with Bluetooth 1.1, 2.0 and 2.0+EDR.[31]Previous versions required users to install their Bluetooth adapter's own drivers, which were not directly supported by Microsoft.[32]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. Windows Vista RTM/SP1 with the Feature Pack for Wireless or Windows Vista SP2 work with Bluetooth 2.1+EDR.[31]Windows 7 works with Bluetooth 2.1+EDR and Extended Inquiry Response (EIR).[31]The Windows XP and Windows Vista/Windows 7 Bluetooth stacks support the following Bluetooth profiles natively: PAN, SPP, DUN, HID, HCRP. The Windows XP stack can be replaced by a third party stack which may support more profiles or newer versions of Bluetooth. The Windows Vista/Windows 7 Bluetooth stack supports vendor-supplied additional profiles without requiring the Microsoft stack to be replaced.[31]Linuxhas two popularBluetooth stacks,BlueZand Affix. The BlueZ stack is included with most Linux kernels and was originally developed byQualcomm.[33]The Affix stack was developed byNokia.FreeBSDfeatures Bluetooth since its 5.0 release.NetBSDfeatures Bluetooth since its 4.0 release. Its Bluetooth stack has been ported toOpenBSDas well.Specifications and features[edit]The Bluetooth specification was developed as a cable replacement in 1994 byJaap Haartsenand Sven Mattisson, who were working forEricssoninLund, Sweden.[34]The specification is based onfrequency-hopping spread spectrumtechnology.The specifications were formalized by theBluetooth Special Interest Group(SIG). The SIG was formally announced on 20 May 1998. Today it has a membership of over 19,000 companies worldwide. It was established byEricsson,IBM,Intel,ToshibaandNokia, and later joined by many other companies.All versions of the Bluetooth standards are designed for downward compatibility. That lets the latest standard cover all older versions.Bluetooth v1.0 and v1.0B[edit]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 v1.1[edit] Ratified asIEEE Standard 802.15.12002[35] Many errors found in the 1.0B specifications were fixed. Added possibility of non-encrypted channels. Received Signal Strength Indicator (RSSI).Bluetooth v1.2[edit]Major enhancements include the following: Faster Connection and Discovery Adaptivefrequency-hopping spread spectrum(AFH), which improves resistance toradio frequency interferenceby avoiding the use of crowded frequencies in the hopping sequence. Higher transmission speeds in practice, up to 721 kbit/s,[36]than in v1.1. 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 concurrent data transfer. Host Controller Interface(HCI) operation with three-wireUART. Ratified asIEEE Standard 802.15.12005[37] Introduced Flow Control and Retransmission Modes for L2CAP.Bluetooth v2.0 + EDR[edit]This version of the Bluetooth Core Specification was released in 2004. The main difference is the introduction of an Enhanced Data Rate (EDR) forfaster data transfer. The nominal rate of EDR is about 3 Mbit/s, although the practical data transfer rate is 2.1 Mbit/s.[36]EDR uses a combination ofGFSKandPhase Shift Keyingmodulation (PSK) with two variants, /4-DQPSKand 8DPSK.[38]EDR can provide a lower power consumption through a reducedduty cycle.The specification is published as "Bluetooth v2.0 + EDR" which implies that EDR is an optional feature. Aside from EDR, there are other minor improvements to the 2.0 specification, and products may claim compliance to "Bluetooth v2.0" without supporting the higher data rate. At least one commercial device states "Bluetooth v2.0 without EDR" on its data sheet.[39]Bluetooth v2.1 + EDR[edit]Bluetooth Core Specification Version 2.1 + EDR was adopted by the Bluetooth SIG on 26 July 2007.[38]The headline feature of 2.1 is secure simple pairing (SSP): this improves the pairing experience for Bluetooth devices, while increasing the use and strength of security. See the section onPairingbelow for more details.[40]2.1 allows various other improvements, including "Extended inquiry response" (EIR), which provides more information during the inquiry procedure to allow better filtering of devices before connection; and sniff subrating, which reduces the power consumption in low-power mode.Bluetooth v3.0 + HS[edit]Version 3.0 + HS of the Bluetooth Core Specification[38]was adopted by the Bluetooth SIG on 21 April 2009. Bluetooth 3.0+HS provides theoretical data transfer speeds of up to24 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 collocated802.11link.The main new feature is AMP (Alternative MAC/PHY), the addition of802.11as a high speed transport. The High-Speed part of the specification is not mandatory, and hence only devices sporting the "+HS" will actually support the Bluetooth over 802.11 high-speed data transfer. A Bluetooth 3.0 device without the "+HS" suffix will not support High Speed, and needs to only support a feature introduced in Core Specification Version 3.0[41]or earlier Core Specification Addendum 1.[42]L2CAPEnhanced modesEnhanced Retransmission Mode (ERTM) implements reliable L2CAP channel, while Streaming Mode (SM) implements unreliable channel with no retransmission or flow control. Introduced in Core Specification Addendum 1.Alternative MAC/PHYEnables the use of alternativeMACandPHYsfor transporting Bluetooth profile data. The Bluetooth radio is still used for device discovery, initial connection and profile configuration, however when large quantities of data need to be sent, the high speed alternative MAC PHY 802.11 (typically associated with Wi-Fi) 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 faster radio is used when large quantities of data need to be sent. AMP links require enhanced L2CAP modes.Unicast Connectionless DataPermits service data to be sent without establishing an explicit L2CAP channel. It is intended for use by applications that require low latency between user action and reconnection/transmission of data. This is only appropriate for small amounts of data.Enhanced Power ControlUpdates the power control feature to remove the open loop power control, and also to clarify ambiguities in power control introduced by the new modulation schemes added for EDR. Enhanced power control removes the ambiguities by specifying the behaviour that is expected. The feature also adds closed loop power control, meaning RSSI filtering can start as the response is received. Additionally, a "go straight to maximum power" request has been introduced. This is expected to deal with the headset link loss issue typically observed when a user puts their phone into a pocket on the opposite side to the headset.Ultra-wideband[edit]The high speed (AMP) feature of Bluetooth v3.0 was originally intended forUWB, but the WiMedia Alliance, the body responsible for the flavor of UWB intended for Bluetooth, announced in March 2009 that it was disbanding, and ultimately UWB was omitted from the Core v3.0 specification.[43]On 16 March 2009, theWiMedia Allianceannounced it was entering into technology transfer agreements for the WiMediaUltra-wideband(UWB) specifications. WiMedia has transferred all current and future specifications, including work on future high speed and power optimized implementations, to the Bluetooth Special Interest Group (SIG),Wireless USBPromoter Group and theUSB Implementers Forum. After the successful completion of the technology transfer, marketing and related administrative items, the WiMedia Alliance will cease operations.[44][45][46][47][48][49]In October 2009 theBluetooth Special Interest Groupsuspended development of UWB as part of the alternative MAC/PHY, Bluetooth v3.0 + HS solution. A small, but significant, number of formerWiMediamembers had not and would not sign up to the necessary agreements for theIPtransfer. The Bluetooth SIG is now in the process of evaluating other options for its longer term roadmap.[50]Bluetooth Smart (v4.0)[edit]The Bluetooth SIG completed the Bluetooth Core Specification version 4.0 (called Bluetooth Smart) and has been adopted as of 30 June 2010. It includesClassic Bluetooth,Bluetooth high speedandBluetooth low energyprotocols. Bluetooth high speed is based on Wi-Fi, and Classic Bluetooth consists of legacy Bluetooth protocols.Bluetooth low energy(BLE), previously known as WiBree,[51]is a subset of Bluetooth v4.0 with an entirely new protocol stack for rapid build-up of simple links. As an alternative to the Bluetooth standard protocols that were introduced in Bluetooth v1.0 to v3.0, it is aimed at very low power applications running off a coin cell. Chip designs allow for two types of implementation, dual-mode, single-mode and enhanced past versions.[52]The provisional namesWibreeandBluetooth ULP(Ultra Low Power) were abandoned and the BLE name was used for a while. In late 2011, new logos Bluetooth Smart Ready for hosts and Bluetooth Smart for sensors were introduced as the general-public face of BLE.[53] In a single mode implementation the low energy protocol stack is implemented solely.CSR,[54]Nordic Semiconductor[55]andTexas Instruments[56]have released single mode Bluetooth low energy solutions. In a dual-mode implementation, Bluetooth low energy functionality is integrated into an existing Classic Bluetooth controller. Currently (2011-03) the following semiconductor companies have announced the availability of chips meeting the standard:Qualcomm-Atheros,CSR,Broadcom[57][58]andTexas Instruments. The compliant architecture shares all of Classic Bluetooths existing radio and functionality resulting in a negligible cost increase compared to Classic Bluetooth.Cost-reduced single-mode chips, which enable highly integrated and compact devices, feature a lightweight Link Layer providing ultra-low power idle mode operation, simple device discovery, and reliable point-to-multipoint data transfer with advanced power-save and secure encrypted connections at the lowest possible cost.General improvements in version 4.0 include the changes necessary to facilitate BLE modes, as well the Generic Attribute Profile (GATT) and Security Manager (SM) services withAESEncryption.Core Specification Addendum 2 was unveiled in December 2011; it contains improvements to the audio Host Controller Interface and to the High Speed (802.11) Protocol Adaptation Layer.Core Specification Addendum 3 revision 2 has an adoption date of July 24, 2012.Core Specification Addendum 4 has an adoption date of February 12, 2013.Bluetooth specification Version 4.1 was officially announced in December 4, 2013.[59]Technical information[edit]Bluetooth protocol stack[edit]Main articles:Bluetooth stackandBluetooth protocols

Bluetooth Protocol StackBluetooth is defined as a layer protocol architecture consisting of core protocols, cable replacement protocols, telephony control protocols, and adopted protocols.[60]Mandatory protocols for all Bluetooth stacks are: LMP, L2CAP and SDP. In addition, devices that communicate with Bluetooth almost universally can use these protocols:HCIand RFCOMM.LMP[edit]TheLink Management Protocol(LMP) is used for set-up and control of the radio link between two devices. Implemented on the controller.AVRCP[edit]Audio/Video Remote Control Profile. AVRCP is designed to provide a standard interface to control TVs, hi-fi equipment, or others to allow a single remote control (or other device) to control all the A/V equipment to which a user has access. It may be used in concert with A2DP or VDP.[61]Commonly used in car navigation systems to control streaming Bluetooth audio.Adopted versions1.0, 1.3, 1.4 & 1.5L2CAP[edit]TheLogical Link Control and Adaptation Protocol(L2CAP) Used to multiplex multiple logical connections between two devices using different higher level protocols. Provides segmentation and reassembly of on-air packets.InBasicmode, L2CAP provides packets with a payload configurable up to 64kB, with 672 bytes as the defaultMTU, and 48 bytes as the minimum mandatory supported MTU.InRetransmission and Flow Controlmodes, L2CAP can be configured either for isochronous data or reliable data per channel by performing retransmissions and CRC checks.Bluetooth Core Specification Addendum 1 adds two additional L2CAP modes to the core specification. These modes effectively deprecate original Retransmission and Flow Control modes: Enhanced Retransmission Mode(ERTM): This mode is an improved version of the original retransmission mode. This mode provides a reliable L2CAP channel. Streaming Mode(SM): This is a very simple mode, with no retransmission or flow control. This mode provides an unreliable L2CAP channel.Reliability in any of these modes is optionally and/or additionally guaranteed by the lower layer Bluetooth BDR/EDR air interface by configuring the number of retransmissions and flush timeout (time after which the radio will flush packets). In-order sequencing is guaranteed by the lower layer.Only L2CAP channels configured in ERTM or SM may be operated over AMP logical links.SDP[edit]TheService Discovery Protocol(SDP) allows a device to discover services offered by other devices, and their associated parameters. For example, when you use a mobile phone with a Bluetooth headset, the phone uses SDP to determine whichBluetooth profilesthe headset can use (Headset Profile, Hands Free Profile,Advanced Audio Distribution Profile (A2DP)etc.) and the protocol multiplexer settings needed for the phone to connect to the headset using each of them. Each service is identified by aUniversally Unique Identifier(UUID), with official services (Bluetooth profiles) assigned a short form UUID (16 bits rather than the full 128).RFCOMM[edit]Radio Frequency Communications(RFCOMM) is a cable replacement protocol used to generate a virtual serial data stream. RFCOMM provides for binary data transport and emulatesEIA-232(formerly RS-232) control signals over the Bluetooth baseband layer, i.e. it is a serial port emulation.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.Many Bluetooth applications use RFCOMM because of its widespread support and publicly available API on most operating systems. Additionally, applications that used a serial port to communicate can be quickly ported to use RFCOMM.BNEP[edit]TheBluetooth Network Encapsulation Protocol(BNEP) is used for transferring 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 toSNAPin Wireless LAN.AVCTP[edit]TheAudio/Video Control Transport Protocol(AVCTP) is 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 player.AVDTP[edit]TheAudio/Video Distribution Transport Protocol(AVDTP) is 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 in the bluetooth transmission.TCS[edit]TheTelephony 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 devices."TCS-BIN is only used by the cordless telephony profile, which failed to attract implementers. As such it is only of historical interest.Adopted protocols[edit]Adopted protocols are defined by other standards-making organizations and incorporated into Bluetooths protocol stack, allowing Bluetooth to code protocols only when necessary. The adopted protocols include:Point-to-Point Protocol (PPP)Internet standard protocol for transporting IP datagrams over a point-to-point link.TCP/IP/UDPFoundation 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.[60]Baseband error correction[edit]Depending on packet type, individual packets may be protected byerror correction, either 1/3 rateforward error correction(FEC) or 2/3 rate. In addition, packets with CRC will be retransmitted until acknowledged byautomatic repeat request(ARQ).Setting up connections[edit]Any Bluetooth device indiscoverable modewill 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.Every device has a unique 48-bit address. However, these addresses are generally not shown in inquiries. Instead, friendly Bluetooth names are used, which can be set by the user. This name appears when another user scans for devices and in lists of paired devices.Most phones have the Bluetooth name set to the manufacturer and model of the phone by default. Most phones and laptops show only the Bluetooth names and special programs are required to get additional information about remote devices. This can be confusing as, for example, there could be several phones in range namedT610(seeBluejacking).Pairing and bonding[edit]Motivation[edit]Many of the services offered over Bluetooth can expose private data or allow the connecting party to control the Bluetooth device. For security reasons it is necessary to be able to recognize specific devices and thus enable control over which devices are allowed to connect to a given Bluetooth device. At the same time, it is useful for Bluetooth devices to be able to establish a connection without user intervention (for example, as soon as they are in range).To resolve this conflict, Bluetooth uses a process calledbonding, and a bond is generated through a process calledpairing. The pairing process is triggered either by a specific request from a user to generate a bond (for example, the user explicitly requests to "Add a Bluetooth device"), or it is triggered automatically when connecting to a service where (for the first time) the identity of a device is required for security purposes. These two cases are referred to as dedicated bonding and general bonding respectively.Pairing often involves some level of user interaction; this user interaction is the basis for confirming the identity of the devices. Once pairing successfully completes, a bond will have been formed between the two devices, enabling those two devices to connect to each other in the future without requiring the pairing process in order to confirm the identity of the devices. When desired, the bonding relationship can later be removed by the user.Implementation[edit]During the pairing process, the two devices involved establish a relationship by creating ashared secretknown as alink key. If a link key is stored by both devices they are said to bepairedorbonded. A device that wants to communicate only with a bonded device cancryptographicallyauthenticatethe identity of the other device, and so be sure that it is the same device it previously paired with. Once a link key has been generated, an authenticatedAsynchronous Connection-Less(ACL) link between the devices may beencryptedso that the data that they exchange over the airwaves is protected againsteavesdropping.Link keys can be deleted at any time by either device. If done by either device this will implicitly remove the bonding between the devices; so it is possible for one of the devices to have a link key stored but not be aware that it is no longer bonded to the device associated with the given link key.Bluetooth services generally require either encryption or authentication, and as such require pairing before they allow a remote device to use the given service. Some services, such as the Object Push Profile, elect not to explicitly require authentication or encryption so that pairing does not interfere with the user experience associated with the service use-cases.Pairing mechanisms[edit]Pairing mechanisms have changed significantly with the introduction of Secure Simple Pairing in Bluetooth v2.1. The following summarizes the pairing mechanisms: Legacy pairing: This is the only method available in Bluetooth v2.0 and before. Each device must enter aPIN code; pairing is only successful if both devices enter the same PIN code. Any 16-byte UTF-8 string may be used as a PIN code; however, not all devices may be capable of entering all possible PIN codes. Limited input devices: The obvious example of this class of device is a Bluetooth Hands-free headset, which generally have few inputs. These devices usually have afixed PIN, for example "0000" or "1234", that are hard-coded into the device. Numeric input devices: Mobile phones are classic examples of these devices. They allow a user to enter a numeric value up to 16 digits in length. Alpha-numeric input devices: PCs and smartphones are examples of these devices. They allow a user to enter full UTF-8 text as a PIN code. If pairing with a less capable device the user needs to be aware of the input limitations on the other device, there is no mechanism available for a capable device to determine how it should limit the available input a user may use. Secure Simple Pairing(SSP): This is required by Bluetooth v2.1, although a Bluetooth v2.1 device may only use legacy pairing to interoperate with a v2.0 or earlier device. Secure Simple Pairing uses a form ofpublic key cryptography, and some types can help protect againstman in the middle, or MITM attacks. SSP has the following characteristics: Just works: As implied by the name, this method just works. No user interaction is required; however, a device may prompt the user to confirm the pairing process. This method is typically used by headsets with very limited IO capabilities, and is more secure than the fixed PIN mechanism which is typically used for legacy pairing by this set of limited devices. This method provides no man in the middle (MITM) protection. Numeric comparison: If both devices have a display and at least one can accept a binary Yes/No user input, they may use Numeric Comparison. This method displays a 6-digit numeric code on each device. The user should compare the numbers to ensure they are identical. If the comparison succeeds, the user(s) should confirm pairing on the device(s) that can accept an input. This method provides MITM protection, assuming the user confirms on both devices and actually performs the comparison properly. Passkey Entry: This method may be used between a device with a display and a device with numeric keypad entry (such as a keyboard), or two devices with numeric keypad entry. In the first case, the display is used to show a 6-digit numeric code to the user, who then enters the code on the keypad. In the second case, the user of each device enters the same 6-digit number. Both of these cases provide MITM protection. Out of band(OOB): This method uses an external means of communication, such asNear Field Communication(NFC) to exchange some information used in the pairing process. Pairing is completed using the Bluetooth radio, but requires information from the OOB mechanism. This provides only the level of MITM protection that is present in the OOB mechanism.SSP is considered simple for the following reasons: In most cases, it does not require a user to generate a passkey. For use-cases not requiring MITM protection, user interaction can be eliminated. Fornumeric comparison, MITM protection can be achieved with a simple equality comparison by the user. Using OOB with NFC enables pairing when devices simply get close, rather than requiring a lengthy discovery process.Security concerns[edit]Prior to Bluetooth v2.1, encryption is not required and can be turned off at any time. Moreover, the encryption key is only good for approximately 23.5 hours; using a single encryption key longer than this time allows simpleXOR attacksto retrieve the encryption key. Turning off encryption is required for several normal operations, so it is problematic to detect if encryption is disabled for a valid reason or for a security attack. Bluetooth v2.1 addresses this in the following ways: Encryption is required for all non-SDP (Service Discovery Protocol) connections A new Encryption Pause and Resume feature is used for all normal operations requiring encryption to be disabled. This enables easy identification of normal operation from security attacks. The encryption key is required to be refreshed before it expires.Link keys may be stored on the device file system, not on the Bluetooth chip itself. Many Bluetooth chip manufacturers allow link keys to be stored on the device; however, if the device is removable this means that the link key will move with the device.Air interface[edit]Theprotocoloperates in the license-freeISM bandat 2.4022.480GHz.[62]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, generally 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[edit]Overview[edit]See also:Mobile security#Attacks based on communication networksBluetooth implementsconfidentiality,authenticationandkeyderivation with custom algorithms based on theSAFER+block cipher. 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.[63]TheE0stream 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.An overview of Bluetooth vulnerabilities exploits was published in 2007 by Andreas Becker.[64]In September 2008, theNational Institute of Standards and Technology(NIST) published a Guide to Bluetooth Security that will serve as reference to organizations 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.[65]Bluetooth v2.1 finalized in 2007 with consumer devices first appearing in 2009 makes significant changes to Bluetooth's security, including pairing. See thepairing mechanismssection for more about these changes.Bluejacking[edit]Main article:BluejackingBluejacking is the sending of either a picture or a message from one user to an unsuspecting user throughBluetoothwireless technology. Common applications include short messages (e.g., "Youve just been bluejacked!").[66]Bluejacking does not involve the removal or alteration of any data from the device.[citation needed]Bluejacking can also involve taking control of a mobile device wirelessly and phoning a premium rate line, owned by the bluejacker.History of security concerns[edit]20012004[edit]In 2001, Jakobsson and Wetzel fromBell Laboratoriesdiscovered flaws in the Bluetooth pairing protocol and also pointed to vulnerabilities in the encryption scheme.[67]In 2003, Ben and Adam Laurie from A.L. Digital Ltd. discovered that serious flaws in some poor implementations of Bluetooth security may lead to disclosure of personal data.[68]In a subsequent experiment, Martin Herfurt from the trifinite.group was able to do a field-trial at theCeBITfairgrounds, showing the importance of the problem to the world. A new attack calledBlueBugwas used for this experiment.[69]In 2004 the first purportedvirususing Bluetooth to spread itself among mobile phones appeared on theSymbian OS.[70]The virus was first described byKaspersky Laband requires users to confirm the installation of unknown software before it can propagate. The virus was written as a proof-of-concept by a group of virus writers known as "29A" and sent to anti-virus groups. Thus, it should be regarded as a potential (but not real) security threat to Bluetooth technology orSymbian OSsince the virus has never spread outside of this system. In August 2004, a world-record-setting experiment (see alsoBluetooth sniping) showed that the range of Class2 Bluetooth radios could be extended to 1.78km (1.11mi) with directional antennas and signal amplifiers.[71]This poses a potential security threat because it enables attackers to access vulnerable Bluetooth devices from a distance beyond expectation. The attacker must also be able to receive information from the victim to set up a connection. No attack can be made against a Bluetooth device unless the attacker knows its Bluetooth address and which channels to transmit on.2005[edit]In January 2005, a mobilemalwareworm known as Lasco.A began targeting mobile phones usingSymbian OS(Series 60 platform) using Bluetooth enabled devices to replicate itself and spread to other devices. The worm is self-installing and begins once the mobile user approves the transfer of the file (velasco.sis) from another device. Once installed, the worm begins looking for other Bluetooth enabled devices to infect. Additionally, the worm infects other.SISfiles on the device, allowing replication to another device through use of removable media (Secure Digital,Compact Flash, etc.). The worm can render the mobile device unstable.[72]In April 2005,Cambridge Universitysecurity researchers published results of their actual implementation of passive attacks against thePIN-basedpairing between commercial Bluetooth devices, confirming the attacks to be practicably fast and the Bluetooth symmetric key establishment method to be vulnerable. To rectify this vulnerability, they carried out an implementation which showed that stronger, asymmetric key establishment is feasible for certain classes of devices, such as mobile phones.[73]In June 2005,Yaniv ShakedandAvishai Woolpublished a paper describing both passive and active methods for obtaining the PIN for a Bluetooth link. The passive attack allows a suitably equipped attacker to eavesdrop on communications and spoof, if the attacker was present at the time of initial pairing. The active method makes use of a specially constructed message that must be inserted at a specific point in the protocol, to make the master and slave repeat the pairing process. After that, the first method can be used to crack the PIN. This attack's major weakness is that it requires the user of the devices under attack to re-enter the PIN during the attack when the device prompts them to. Also, this active attack probably requires custom hardware, since most commercially available Bluetooth devices are not capable of the timing necessary.[74]In August 2005, police inCambridgeshire, England, issued warnings about thieves using Bluetooth enabled phones to track other devices left in cars. Police are advising users to ensure that any mobile networking connections are de-activated if laptops and other devices are left in this way.[75]2006[edit]In April 2006, researchers fromSecure NetworkandF-Securepublished a report that warns of the large number of devices left in a visible state, and issued statistics on the spread of various Bluetooth services and the ease of spread of an eventual Bluetooth worm.[76]2007[edit]In October 2007, at the Luxemburgish Hack.lu Security Conference, Kevin Finistere and Thierry Zoller demonstrated and released a remote root shell via Bluetooth on Mac OS X v10.3.9 and v10.4. They also demonstrated the first Bluetooth PIN and Linkkeys cracker, which is based on the research of Wool and Shaked.Health concerns[edit]Main article:Wireless electronic devices and healthBluetooth uses themicrowaveradio frequencyspectrum in the 2.402GHz to 2.480GHz range.[62]Maximum power output from a Bluetooth radio is 100mWfor class 1, 2.5mW for class 2, and 1mW for class 3 devices. Even the maximum power output of class1 is a lower level than the lowest powered mobile phones.[77]UMTS&W-CDMAoutputs 250mW,GSM1800/1900outputs 1000mW, andGSM850/900outputs 2000mW.Bluetooth Innovation World Cup marketing initiative[edit]TheBluetoothInnovation World Cup, a marketing initiative of the Bluetooth Special Interest Group (SIG), is an international competition encouraging the development of innovations for applications leveraging theBluetoothlow energy wireless technology in sports, fitness and health care products. The aim of the competition is to stimulate new markets. The initiative will take three years, having started 1 June 2009.[78]BluetoothInnovation World Cup 2009The first internationalBluetoothInnovation World Cup 2009 drew more than 250 international entries, includingNokia,Freescale Semiconductor,Texas Instruments,Nordic Semiconductor,STMicroelectronicsandBrunel.BluetoothInnovator of the Year 2009On 8 February 2010, Edward Sazonov, Physical Activity Innovations LLC, was awarded the title ofBluetoothInnovator of the Year for 2009. Sazonov received this recognition at a ceremony held at the Wearable Technologies Show at ispo 2010, a trade show for sporting goods. The award includes a cash prize of 5,000 and aBluetoothQualification Program voucher (QDID) valued at up to US$ 10,000. Sazonovs idea, The Fit Companion, is a small, unobtrusive sensor that, when clipped-on to a users clothing or integrated into a shoe, provides feedback about physical activity. The data, transmitted via Bluetooth, can help individuals to lose weight and achieve optimal physical activity. Intended for use in both training and daily activities like walking or performing chores, this simple measuring device may offer a solution for reducing obesity.BluetoothInnovationWorld Cup 2010The Bluetooth SIG announced the start of the second Innovation World Cup on 1 June 2010, with a focus on applications for the sports & fitness, health care, and home information and control markets. The competition closed for registration on 15 September 2010.