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BIuetooth IntroductionBluetooth isa forever,limited radioconnect thatresides on amicrochip.It wasoriginally expandedthrough Swedishmo bilephone creatorEricsson in1994as amethod tolet laptop computersmake callsabove a mobile phone.As then,num erousorganizations havesigned onto createBluetooth thelow-power thoughtlesswireless averagefor abroad variety of devicesLeVitus,216-
220.Industry spectatorsanticipate Bluetoothto befitted inbillions ofdevices through
2005.Discussion Developedby engineersat Ericssonin thelate1990s,Blue toothis moreand morespecial technologythat facilitatest houghtlesswireless communicationamong adiversity ofelectro nicdevices.Its mainlyimportant aspectis thatit permitsdevices to“talk”relocate andorchestrate datawirelessly with each other,terminating therequirement for the outwardly continuoustangle ofcables,cords,and adaptersimportan tfor numeroustoday sexpertise.The BluetoothSpecial InterestGroup SIGwas formedin1998to managethe expansionand prologueof Bluetoothknowle dgeLeVitus,216-
220.IBM,Intel,Toshiba andNokia connectedwith Ericssonas thebeginning associatesof the SIG,and inexc essof8,000organizations havecontracted since.So as to tradeproducts with the Bluetoothrequirement andlogo,manufacturers shouldbe associatesof theSIG and the devicesshould meetwell-outlined credentials.These proceduresmake surethat Bluetoothwireless devices international mayconverse witheach other,apart fromcompany ornation of allowing radiosto bepowered downwhen inactive.The GenericAlternate MAC/PHY inVersion
3.0HS enablesthe discoveryof remoteAMPs for high speeddevices andturns on the radioonly whenneeded fordata transfergiving ap oweroptimization benefitas wellas aidingin thesecurity of the radios.Bluetooth lowenergy technology,optimized fordevices requiring maximumbattery lifeinstead ofa highdata transferrat e,consumers between1/2and1/100the powerof classicBlu etoothtechnology.SECURITY Mobilityand openof Bluetooth system makessafety problemsextremely important.Although thefrequency modulationtechniqu eused byBluetooth systemhas alreadyprovided a certain security,but Bluetooth system stillneed safetymanagement tolink layer and applicationlayer.In linklayer,Bluetooth systemprovides authentication,encryption andkey management,and otherfunctions.Each userhas aPersonal Identification NumberPIN,which will be translatedinto128bit linkkey forone-way orboth-way certification.Once theauthentication finished,link willuse encryphonkey toencrypt.The linklayer securitymechanism providesa greatdeal ofcertification schemesand aflexible encryptionscheme meansallow theconsultation of the lengthof password.This mechanism is very importantwhen the equipments incommunicatio nare fromdifferent countries,because somecountries willspecify maximumpassword length.Bluetooth systemwill selectthe smallestmaximum allowablepassword lengthofallequip mentsin thepiconet.Bluetoothsystemalso supportsthe highlevel ofprotocol stack indifferent applicationsof specialsecurity mechanisms.Bluetooth securitymechanism buildstrust relationshipbetwee ndevices relyingon pins.Once thisrelationship established,these pinscan bestored in theequipment,in order to connectionmore quicklythe nexttime.Source:Baidu Library蓝牙介绍蓝牙是一种永久、有限的无线连接,驻留在微芯片上1994年,它最初是通过瑞典手机制造商爱立信Ericsson扩展的,作为一种让笔记本电脑在手机上方拨打电话的方法当时,许多组织已经签署了创建蓝牙的协议,这是一种低功耗、轻率的无线设备,适用于各种设备LeVitus,216-220o业内人士预计,到2005年,蓝牙将安装在数十亿台设备上讨论蓝牙是爱立信公司的工程师在20世纪90年代末开发的一种越来越特殊的技术,它可以促进各种电子设备之间的无意识无线通信其主要的重要方面是,它允许设备之间以无线方式“对话”重新定位和编排数据,从而终止了对电缆、跳线和适配器的外部连续缠绕的要求,这对当今众多专业技术来说都很重要蓝牙特别利益小组SIG成立于1998年,负责管理蓝牙的扩展和开场白LeVitus,216-220o IBM、英特尔、东芝和诺基亚与爱立信建立了联系,成为SIG的最初合作伙伴,自那时以来,已有超过8000家公司签约为了交易具有蓝牙要求和标志的产品,制造商应是SIG的合作伙伴,设备应符合良好的认证要求这些程序可确保蓝牙无线设备国际公司可以与其他公司或国家进行对话速度和范围范围是特定于应用程序的,尽管核心规范规定了最小范围,但没有限制,制造商可以调整其实现以支持他们正在启用的用例范围可能因实施中使用的无线电类别而异•3类无线电的射程可达1米或3英尺•2类无线电最常见于移动设备中,其射程为10米或33英尺•主要用于工业用途的1类无线电的射程为100米或300英尺这创造了蓝牙技术,适用于传输较小的文件,例如手机合同和文本文档,以及较低质量的图片和音频Kumkum,160-162以这些重新定位的速度;蓝牙在这方面可能不会真正处理流式视频或高质量的图片和音频,除非将来新的蓝牙标准启动后,这种情况可能会改变简单且能使用创建和配置允许使用蓝牙的设备相当简单,只需将两台设备靠近并缠绕在一起,就不会有什么额外的麻烦不需要安装驱动程序或其他软件来复杂一个特殊的个人无线网络Kumkum,160-162o它有一个统一的组织,这意味着,某些属于蓝牙技术的两种无线产品,无论其产品或原产国如何,都能够完美地相互对话常见应用蓝牙的一个主要普通应用是免提手机程序在我们这个时代,几乎每一部手机都构建了蓝牙Meier,15-20只需将手机与蓝牙耳机配对,他就可以在手机放在钱包或口袋里时通话今天的几款车载立体声系统也在他的车上安装了蓝牙免提通话功能如果他的车有一个他不想恢复的立体声或成熟的售后服务,他可能会喜欢用蓝牙车载套件进行免提识别蓝牙
3.0蓝牙
3.0是典型的通过蓝牙SIG于2009年4月21日,通过新鲜的蓝牙无线新鲜的标准支持提升数据删除速度和结构,前面的标准迈尔15-20o凭借其出众的速度,有可能transfigure消费电子行业的技术技术协议蓝牙技术标准的设置,使不同的应用程序可以相互“沟通”在远程通信设备使用相同的协议栈,而不同的应用需要不同的协议栈但是,每一个应用程序需要的数据链路层和物理层的蓝牙技术整个蓝牙协议栈所示的打击任何应用程序不应该使用的所有协议,但其中一个或一些名单下面的图表显示了协议之间的关系,但在某些应用中的关系可能会改变完全的协议栈包括蓝牙特殊协议LMP和L2CAP,而不是特殊的如0BEX和UDP设计协议和协议栈的基本原则是,尽可能利用现有的高层协议,确保协议和蓝牙技术相结合,采取适应的蓝牙技术标准的软件和硬件的最佳优势开放的蓝牙技术,使得设备制造商可以自由选择的协议,因为他们喜欢或使用蓝牙协议体系中的协议据SIG的有4层蓝牙协议体系核心协议电缆替代协议电话控制协议通过协议除上述协议层,该标准还定义了主机/控制器接口(HCI),它提供基带控制器,连接管理器,硬件状态和控制寄存器的命令接口蓝牙核心协议包括由SIG提出的特殊协议大多数蓝牙设备需要核心协议,而其他协议取决于应用的需要毕竟,电缆替代协议,技术控制协议,通过协议和基于核心协议,构成了面向对象的协议核心协议LMP(链路管理协议)用于两个设备之间的无线链路控制控制器上实现通过开展交流和检查连接的识别和加密,并决定基带数据包通过会议的规模它还控制无线设备的电源模式和工作周期,并在微微网单元设备的连接状态的L2cAp(逻辑链路控制与适配协议)该协议用于复用多个逻辑连接两个使用不同的高层协议的设备之间,提供分割和重组的空气包L2CAP的基本模式,提供与有效载荷配置多达64KB的数据包,为672个字节的默认MTU,48个字节的最低强制性支持的MTUo L2CAP的转播及流量控制模式,可以被配置为每个通道的可靠或同步数据进行转播和CRC检查蓝牙核心规范附录1增加了两个额外的L2CAP模式的核心规范这些模式有效地贬低原重发和流量控制模式增强重传模式(ERTM)这种模式是一种原始的转播模式的改进版本这种模式提供了可靠的L2cAp信道流模式(SM)这是一个非常简单的模式,没有转播或流量控制这种模式提供了一个可靠的L2cAp信道在这些模式中的任何可靠性,选择性和/或另外下层BDR的/EDR的蓝牙空气通过配置重传和的冲洗超时(时间之后,无线电将刷新包)接口保证保证下层顺序排序ERTM或SM只有配置的L2cAp通道可运行超过AMP的逻辑联系SDP(服务发现协议)服务发现协议(SDP)允许设备发现其他设备,其相关参数的支持服务例如,当手机连接到蓝牙耳机,社民党将用于确定哪些支持蓝牙配置文件耳机(耳机模式,免提配置文件,高级音频分配模式(A2DP)等)和协议复用器设置需要连接到他们每个人每个服务标识通用唯一标识符(UUID)分配一个短形式的UUID(16位),而不是完整的128/vichitra官方服务(蓝牙模式),电缆替代协议(RFCOMM协议)无线电频率通信(RFCOMM协议)是一种电缆替代协议,用于创建一个虚拟的串行数据流RFCOMM协议提供二进制数据传输和模拟的EIA-232(RS-232)在蓝牙基带层的控制信号RFCOMM协议提供给用户一个简单可靠的数据流,类似于TCP它被用于许多与电话相关的配置文件直接作为AT命令的载体,以及通过蓝牙OBEX传输层电话控制协议(TCP)o电话控制协议二进制(塔塔咨询服务公司的BIN)是面向比特的协议,它定义了呼叫控制蓝牙设备之间的语音和数据呼叫建立信令此外,“塔塔咨询服务公司的BIN定义用于处理蓝牙TCS的设备组的流动性管理程序”TCS-BIN仅用于无绳电话模式,该模式未能吸引实施者因此,它只具有历史意义通过协议通过协议定义其他组织的标准制定,并纳入蓝牙协议栈,允许蓝牙协议只在必要时所采用的协议包括点的点对点协议(PPP)互联网点至点链接的IP数据报传输的标准协议的TCP/IP/UDP的连接到互联网的设备进行通信对象交换协议(OBEX)会话层协议的交换对象,提供了一个模型对象和操作表示它采用客户-服务器模式无线应用环境/无线应用协议(WAE/WAP)WAE指定用于无线设备和WAP是一个开放的标准,向移动用户提供电话和信息服务的访问的应用程序框架技术频谱与干扰蓝牙技术在
2.4至
2.485GHz的未经许可的工业、科学和医疗(ISM)频段上运行,使用扩频、跳频、全双工信号,标称速率为1600跳/秒在大多数国家,
2.4GHz ISM频段是可用的且未经许可SIM频段对所有无线电系统开放,因此使用某个频段会遇到不可预测的干扰源因此,蓝牙设计了特殊的快速应答和跳频技术来保证链路的稳定性跳频技术将频带分成多个跳频信道,在一个连接中,无线电收发机根据一定的码序列不断地从一个信道“跳”到另一个信道只有发送方和接收方根据此规则进行通信,其余的干扰可能不遵循相同的规则跳频的瞬时带宽很窄,但通过扩频技术可以使窄带带宽扩展到宽带,使得干扰的影响可能变得很小与其他工作在同一频段的系统相比,蓝牙的跳频速度更快,数据包更短,稳定性更强纠错蓝牙支持电路交换和分组交换两种技术,定义了两种链路连接类型,即面向连接的同步链路(SCO)和面向无连接的异步链路(ACL)o蓝牙使用三种纠错模式1/3前向纠错(FEC)、2/3前向纠错和自动重传请求(ARQ)纠错的目的是减少重传的可能性,同时增加额外费用,但在合理的无差错环境中,冗余投标将减少输出因此,包定义本身也保持了灵活的方式因此,可以定义软件是否采用FEC一般来说,当信道噪声较大时,蓝牙系统会使用FEC,为了保证通信质量对于SCO链路,使用1/3的FEC;ACL链接中使用了2/3FEC在无编号ARQ中,在一个时隙中发送的数据必须在下一个时隙中收到接收确认只有在接收端进行报头错误检测和CRC校验后,确认数据无误后,才会将确认发送给发送方,或返回错误消息范围范围是特定于应用程序的,尽管核心规范规定了最小范围,但没有限制,制造商可以调整其实现以支持他们正在启用的用例范围可能因实施中使用的无线电类别而异3类无线电的射程可达1米或3英尺2类无线电最常见于移动设备中,其射程为10米或33英尺主要用于工业用途的1类无线电的射程为100米或300英尺电力为了使蓝牙设备也可以连接,即使是在一个非常低的功率状态,蓝牙规定了三种节能状态驻车状态、保持状态和嗅探状态这些状态的节能效率下降一个接一个最常用的无线电为2级,用户功率为
2.5mW蓝牙技术被设计成具有非常低的功耗规范中通过允许收音机在不活动时关闭电源加强了这一点版本
3.0HS中的通用备用MAC/PHY仅在数据传输需要时才允许在无线电上发现高速设备和TUM的远程放大器,从而实现功率优化,并有助于无线电的安全性蓝牙低能耗技术,针对需要最大电池寿命而非高数据传输速率的设备进行了优化,用户的电量介于经典蓝牙技术的1/2到1/100之间安全蓝牙系统的移动性和开放性使得安全问题变得极其重要虽然蓝牙系统采用的调频技术已经提供了一定的安全性,但蓝牙系统仍然需要对链路层和应用层进行安全管理在链路层,蓝牙系统提供认证、加密和密钥管理等功能每个用户都有一个个人识别码(PIN),该识别码将转换为128位链接密钥,用于单向或双向认证身份验证完成后,link将使用encryphon密钥进行加密链路层安全机制提供了大量的认证方案和灵活的加密方案(即允许咨询密码长度)当通信设备来自不同国家时,这种机制非常重要,因为有些国家会指定最大密码长度蓝牙系统将选择微微网中所有设备允许的最小最大密码长度蓝牙系统还支持高级协议栈在不同应用中的特殊安全机制o蓝牙安全机制在依赖PIN的设备之间建立信任关系一旦建立了这种关系,这些引脚就可以存储在设备中,以便下次更快速地连接derivation.Speed andRange Rangeis applicationspecific andalthough aminimum rangeis mandated by the Core Specification,there is not alim itand manufacturers can tune their implementation to support the use case they are enabling.Range mayvary dependingon classof radioused in an implementation:•Class3radios-have arange ofup to1meter or3feet•Class2radios-most commonlyfound inmobile devices,have arange of10meters or33feet.•Class1radios-used primarilyin industrialuse cases,have arange of100meters or300feet.That createsBluetooth technologyappropriate fortransporting lesserfiles forexample cell phone contractsand textdocuments,also aslower-quality picturesand audioKumkum,160-
162.At theserelocate speeds;Bluetooth may not actuallydeal streaming videoorhigh-quality picturesand audioat thisend,except thispossibly willalter inthe futurewhen freshBl uetoothstandards areinitiated.Simple andCompetent toUtilize Creatingand configuringBluetooth alloweddevices ismodera telyuncomplicated,with littleextra commotionthan acquirethe two devices closeto oneanother andtwist themon.Ther eisnorequirement tomount driversor furthersoftware tocomplex anad-hoc,personal wirelessnetwork Kumkum,160-
162.It has a uniformorganization,meaning thatsome twowireles sproducts attributingBluetooth technology,despite ofproduct ornation oforigin,have theability toconverse faultlessly witheach other.Common ApplicationsOne of the mainlyordinary applicationsof Bluetoothis hands-free cellphone procedure.About eachcellphonefashioned inour dayhas constructedBluetooth Meier,15-
20.Only pairphone with a Bluetooth headset,and he may talkwhereas hisphone isin hispurse orpocket.Several oftodays carstereo sas wellhave fittedBluetooth forhands-free callingin his vehicle.And ifhisvehiclehas aplant stereoor grown-up aftermarketone that he merelydoesn twish torestore,hemayyet likehands-free identifyingwitha Bluetooth carkit.Bluetooth
3.0Bluetooth
3.0is thefresh Bluetoothwireless typicaladopted throughthe BluetoothSIG onApril21,
2009.The freshst andardsupports elevateddata removespeeds andconstructs ahead thepreceding standardsMeier,15-
20.With itssuperior speed,the technologyhas theprobable totransfigure theco nsumerelectronics industry.PROTOCOL TheBluetooth technologystandard isset tomake differenta pplicationscan“communicate”witheachother.Remote devicesincommunication usethe sameprotocol stacks,while different applicationsneed differentprotocol stacks.But,every application needs the data linklayerandphysical layerof the Bluetooth technology.The wholeBluetooth protocol stacks is shown asb1ow.Not anyapplication shoulduse alloftheprotocols,but oneor somelists of these.The chartb elowshows therelationship betweenprotocols,but therelati onshipmay changein someapplications.The completelyprotocolstacksinclude Bluetoothspecial protocols likeLMP andL2CAP andnot specialones suchas OBEX andUDP.The basicprinciple fordesigning protocoland protocolstacks isthat useexisting highlevelprotocol asp ossible,ensure thecombination ofprotocols andBluetooth technology,and takethe bestadvantage ofthe softwareand hardware whichadapt to theBluetooth technology standards.Th eopen Bluetoothtechnology makesdevice manufacturerscan choose protocolsfreely asthey likeor used to.The protocolsin Bluetoothprotocol system.There arefour layersin Bluetoothprotocol systemaccording totheSIG:•Core protocols•Cable replacement protocols•Telephony controlprotocols•Adopted protocolsExcept theprotocol layersabove,the standardalso definesHost/Controller InterfaceHCI,which providescommand interfacefor baseband controller,connection manager,hardware stateandcontrolregister.Bluetooth core protocols consistofthespecial protocolsmad eby SIG.Most Bluetoothdevices needcore protocols,while otherprotocols areused dependonneedsoftheapplication.After all,cable replacementprotocols,technology controlp rotocolsand adopted protocols basedonthecoreprotocolsc onstitutethe object-oriented protocols.•Core protocols•LMP LinkManagement ProtocolUsed forcontrol ofthe radiolink between twodevices.Implemented onthe controllers.It identifiesand encryptsthrough launching,exchanging andchecking theconnection,and decidesthe sizeof basebandda tapackets throughconference.It alsocontrols thepower mode andwork cycleof wirelessequipment,and connectionstat usof unitequipment inpiconet.•L2CAP LogicalLink ControlAdaptation ProtocolThis protocolis usedto multiplexmultiple logicalconnectio nsbetweentwodevices usingdifferent higherlevel protocols,and providessegmentation andreassembly ofon-air packets.In Basicmode,L2CAP providespackets witha payloadconfigu rableup to64kB,with672bytes asthe defaultMTU,and48bytes asthe minimummandatory supportedMTU.In RetransmissionFlow Control modes,L2CAP can be configured forreliable orisochronous dataper channelby performing retransmissions and CRCchecks.Bluetooth CoreSpecification Addendum1adds twoadditional L2CAP modestothecore specification.These modeseffectively deprecateoriginal Retransmissionand FlowControlmodes:•Enhanced RetransmissionMode ERTM:This modeis animprov edversion ofthe originalretransmission mode.This modepr ovidesa reliableL2CAP channel.•Streaming ModeSM:This isa verysimple mode,with noretransmissionor flowcontrol.This modeprovides anunreliabl eL2CAP channel.Reliability inany ofthese modesis optionallyand/or additionally guaranteedby thelower layerBluetooth BDR/EDR airinterface byconfiguring thenumber of retransmissionsandfl ushtimeout timeafter whichthe radiowill flushpackets.In-order sequencingis guaranteedby thelower layer.Only L2CAP channelsconfigured inERTM orSM maybe operated overAMP logicallinks.•SDP Service Discovery ProtocolServiceDiscoveryProtocol SDPallows adevice todiscover servicessupported by other devices,and theirassociated parameters.For example,when connectingamobilephone toaBluetoothheadset,SDP willbe usedfor determiningwhich Bluetooth profilesare supportedby theheadset HeadsetProfile,Hands FreeProfile,Advanced AudioDistribution ProfileA2DP etc.and theprotocol multiplexersettings neededto connectto eachof them.Each serviceis identifiedby aUniversall yUnique IdentifierUUID,with officialservices Bluetoothprofiles assigneda shortform UUID16bits ratherthan the full128/vichitra•Cable replacementprotocolsRFCOMM Radiofrequency communicationsRFCOMM isa cablereplacementprotocolusedto create avirtual serialdata stream.RFCOMM providesfor binarydata transportand emulatesEIA-232formerly RS-232control signalsover theBluetooth basebandlayer.RFCOMM providesa simplereliable datastream tothe user,similar toTCP.It isused directlyby manytelephony related profilesasacarrier forAT commands,as wellas beinga transportlayer forOBEX overBluetooth.•Telephony controlprotocols TCP.Telephony controlprotocol-binary TCS BIN isthe bit-oriented protocolthat definesthe callcontrol signalingfor theestablishment ofvoice anddata callsbetween Bluetoothdevices.Additionally,“TCSBINdefines mobilitymanagement procedures forhandling groupsof BluetoothTCS devices.”TCS-BIN isonly usedby thecordless telephonyprofile,which failedto attractimplementers.As suchit isonly ofhistorical interest.Adopted protocolsAdopted protocolsare definedbyothers tandards-mak ing organizationsand incorporatedinto Bluetooth,s protocolstack,allowing Bluetoothtocreateprotocols onlywhen necessary.T headoptedprotocolsinclude:•Point-to-Point ProtocolPPP:Internet standardprotocol fortransporting IPdatagrams overa point-to-point link.•TCP/IP/UDP:For communicatingwiththedevice connectedto Internet.•Object ExchangeProtocol OBEX:Session-layer protocolfortheexchange ofobjects,providing amodel forobject andoperation representation.It usesthe client-server mode.•Wireless ApplicationEnvironment/Wireless ApplicationProtocol WAE/WAP:WAE specifiesan applicationframework forwireless devicesand WAPis anopen standardto providemobile usersaccess totelephony andinformation services.Techno IogySPECTRUM ANDINTERFERENCE Bluetoothtechnology operatesintheunlicensed industrial,sc ientificand medicalISM bandat
2.4to
2.485GHz,using aspread spectrum,frequency hopping,full-duplex signalat anominal rateof1600hops/sec.The
2.4GHz ISMband isava ilableand unlicensedin mostcountries.SIM frequency band isopen toall radiosystem,So theuse ofacertainfrequency bandwill meetunpredictable interference sources.Therefore,Bluetooth designsspecial fastackno wledgeand frequency hopping technique to ensurethe stabilityof link.Frequency hoppingtechniquetodivide theband into manyfrequency hoppingchannels,inaconnection,radio transceiver“jump”from achannel toanother constantlyacc ordingto certaincode sequence.Only senderand receiverco mmunicateaccording tothis law,andtherest ofinterferenc emaynotpress the same rule.The instantaneousbandwidth ofFrequency hoppingisverynarrow,but throughthe spreadspectrum technologyit canmake thenarrow bandwidthone hundred timesexpanded intowideband,making theinfluence ofinterference maybecome verysmall.Comparing toother systems thatwork inthesamefrequencyband,frequencyhoppingof Bluetoothworks faster,data packetof Bluetoothisshorter,which makeit morestable thanthe other.ERROR CORRECTIONBluetooth supportscircuit switchingand packetswitching twotechniques,and definestwo typesoflinkconnection,namel yconnection-oriented synchronouslink SCOand connectionless-oriented asynchronouslink ACL.Bluetooth usethree errorcorrection models:1/3Forward Error Correction FEC,2/3forward ForwardErrorCorrectionand Automatic RepeatRequest ARQ.Purpose tothe errorcorrection isto reducethe possibilityofretransmission,while atthesame timeincrease theextra expenses,but ina reasonable errorlessenvironment,redundant bidswill reduceoutput.So thepacket definitionitself alsokeeps flexibleways.He neethe softwarecanbedefined whetherto adoptFEC.In general,when thechannel noiseis large,Bluetoothsystemwill usesFEC,in orderto ensurethe qualityof communication:astoSCO link,1/3FEC isused;2/3FEC isused inACL link.In UnnumberedARQ,thedatasend ina time slot mustreceive aconfirmation ofreceipt inthe nexttimeslot.On lywhen thedata ischecked tobe withoutmistake afterhe adererror detectionand CRCat receiverwill theconfirmati onsent tosender,or anerror messagewillbesent back.RANGE Rangeis applicationspecific andalthough aminimum rangei smandatedbytheCoreSpecification,there isnot alimit andmanufacturerscantunetheirimplementationtosupporttheusecasetheyareenabling.Range mayvary dependingon classof radioused inan implementation:Class3radios-have arange ofup to1meter or3feet.Class2radios-most commonlyfound inmobiledevices,have arange of10meters or33feet.Class1radios-used primarilyinindustrial usecases,have arange of100meters or300feet.POWER Inordertomake aBluetooth equipmentcan alsobe inconn ectioneven ina very low powerstate,Bluetooth stipulatesthree energysaving state:Park state,Hold stateand Sniff state.The energysaving efficiencyofthesestates declines oneby one.The mostcommonly usedradio isClass2and users
2.5mW ofpower.Bluetoothtechnologyis designedto haveverylowp owerconsumption.This isreinforced inthe specificationby。