TABLEOFCONTENTS:
1.BluetoothProtocol(Part2):Types,DataExchange,Security
2.BluetoothProtocolCategories
3.InternalDetailsofBluetoothProtocols
4.BluetoothCoreProtocols
5.CableReplacementProtocols
6.AdoptedProtocols
7.TelephonyControlProtocol
BluetoothProtocol(Part2):Types,DataExchange,Security
ERRORCORRECTION
Therearethreetypesoferrorcorrectionschemes:1/3rateFEC,2/3FECandARQscheme.In1/3
rateeverybitisrepeatedthreetimesforredundancy,in2/3apolynomialisgeneratedtoencode10
bitcodetoa15bitcodeandinARQschemeapacketistransmittedtillanacknowledgementis
received.ItusespositiveandnegativeacknowledgementvaluesbysettingappropriateARQN
values.IFtimeoutisexceeded,Bluetoothdeviceflushesthepacketandproceedtonextone.
FLOWCONTROLANDSYNCHRONIZATION
BluetoothusestheconceptoffirstinfirstoutFIFOqueuesinACLandSCOlinksfortransmission
andreception.Linkmanagerfillsthequeuesandlinkcontrolleremptiesthemautomatically.
Ifthereceptionqueuesarefull,flowcontrolisusedtoavoidthedroppingofpacketsandcongestion.IfdataisnotreceivedaSTOPindicationis
transmittedbyLinkcontrollerofthereceiverintoheaderofthereturnpacket.WhenthetransmitterreceivestheSTOPindicationitfreezesitsFIFO
queues.Againwhenreceiverisreadyitsendsapacketwhichresumestheflowagain.
CONTROLLERSTATES
Thestateisalastknownorcurrentstatusofanapplicationoraprocess.BluetoothoperatesintwostatesStandbyandconnection.Thereareseven
sub-stateswhichareusedtoaddslavesormakeconnectionsinPico-net.Theseareshowninthefigure:
Thestandbystateisthedefaultlowpowerstateusedwhenthereisnointeractionbetweenthedevices.Inconnectionstatethemasterandslavecan
exchangepacketsusingchannelaccesscode.
NAMEDESCRITIOPN
PAGEThissub-stateisusedbythemastertoactivateandconnecttoaslave.Mastersendspagemessagesbytransmitting
slave''sdeviceaccesscode(DAC)indifferenthopchannels.
PAGESCANInthissub-state,aslavelistensforitsowndeviceaccesscode(DAC)fordurationofscanwindow.Theslavelistensata
singlehopfrequency(derivedfromitspagehoppingsequence)inthisscanwindow
SLAVERESPONSESlaverespondstomaster''spagemessageinthissub-statewhichisresultedifslavecorrelatesinthepagescansub-stateto
themaster''spagemessage.SlaveentersConnectionstateafterreceivingFHSpacketfrommaster.
MASTERRESPONSEMasterreachesthissub-stateafteritreceivesslave''sresponsetoitspagemessageforit.MastersendsaFHSpacketto
slaveandifslaverepliesthenmasterentersConnectionstate.
INQUIRYInquiryisusedtofindtheidentityoftheBluetoothdevicesinthecloserange.ThediscoveringunitcollectstheBluetooth
deviceaddressesandclocksofallunitsthatrespondtotheinquirymessage.
INQUIRYSCANInthisstate,theBluetoothdevicesarelisteningforinquiriesfromotherdevices.Inthisscanningdevicemaylistenforgeneral
inquiryaccesscode(GIAC)ordedicatedinquiryaccesscodes(DIAC).
INQUIRYRESPONSEForinquiry,onlyslaverespondsbutnotthemaster.TheslaverespondswiththeFHSpacketwhichcontainstheslave''s
deviceaccesscode,nativeclockandsomeotherslaveinformation.
Aconnectionbetweentwodevicesfollowsaparticularway.FirstmasterinquiresaboutBluetoothdevicesintherange.IfanyBluetoothdeviceis
listeningfortheseinquires(inquiryscansub-state),itrespondstomasterbysendingaddressandclockinformation(FHSpacket)tothemaster9
inquiryresponsestate.Aftersendingtheinformation,theslavestartslisteningforthepagemessagesfromthemaster(pagescan).Thenmasterafter
discoveringtheBluetoothdevicesintherangemaypagethesedevices(pagesub-state)forconnectionsetup.Theslaveinthepagescanmodewill
respondifpagedbythemaster(slaveresponsesub-state).Themasterafterreceivingtheresponsefromtheslavemayrespondbytransmittingthe
masterrealtime,mastersBD-ADDR,theparitybitsandtheclassofdevice(FHSpacket).OncetheybothreceivethisFHSpackettheyenterin
connectionstate.
CONNECTIONSTATE
Aconnectionstatestartswithapacketsentbymastertoverifythatslavehasswitchtothemasterstimingandchannelfrequencyhopping.Theslave
canrespondbysendinganytypeofpacket.Variousconnectionstatesare
ACTVEInthismodebothmasterandslaveactivelyparticipatesonthechannelbylistening,transmittingorreceiving.
Masterandslavebothsynchronizewitheachother.
SNIFFInthismodeslaveratherthanlisteningtothemaster’smessageforthatslave,itsniffsonthespecifiedtimeslotsfor
itsmessages.Henceitcangotosleepmodetosavepower.
HOLDInthismode,adevicetemporarydoesnotsupporttheACLpacketsandgoestolowpowersleepmodetoallow
activitieslikepagescan,pageinquiryetc.
PARKWhenslavedoesnotwantstoparticipateinPico-netbutstillwantstosynchronizeinthechannelitgoesintopark
modewhichisalowpoweractivity.
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