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Seminar By Vishnu P.G S7 ECE A 62
Introductiony We know that air passengers are required to switch off
their mobile phones on board any flight.This is because
I.
Signals emitted by mobile phone interfere with Air Traffic Control (ATC) Signals.
II.
A mobile at such a high altitude connects to multiple base stations simultaneously
What is Sky M biley Sky M bile is a
vel s l ti
f r the previ
sly isc sse iss e. f
y It helps t remai c
ecte i the flight si g the i tegrati li ks:
iverse c mmy Bl et
icati
th
y Cell lar Netw rk(GSM/IS-95) y PSTN y Air t Gr
C
ecti
System Overviewy The mai feat res f this system arey The switch ver fr m the cell lar etw rk t the bl et
th
etw rk is a t matic,y Users ph
es t req ire a y ser i itiati receives calls as i
e
mber stays the same, a
a s al m biley N cha ge f ha
set req ire while b ar i g a flight
Perf rma ce Req ireme tsy The cha ge i the c y Sh
ecti
sh
l be seamless with egative fail re
l be able t establish c
ecti
ratey C mparable v ice clarity y Sec rity meas res t preve t
a th rise
sage
System Desigy System consist of 3 hardware unitsy Mobile Unit(a bluetooth enabled mobile handset) y Bluetooth Airplane Gateway (BTAG) y Ground Switching Center (GSC)
yTy y y
r ar t r S ST
soft ar
odul s S ST ) unication ov r t ork)
odul (int rfac s to t odul (int rfac s to t
lu tootlu toot )
odul (To carry out voic co
Why Bl e ty It y It ses Fre y There y it i y It
thHz (FHSS) ing S read S ectr nity fr
erates ithin 2.4 2.483 ency H r ves i
interference t 100
erates ithin
er ratings f less than 1
How Sky Mobile worksy
utomatic etection of mobile forwarding and SM switc off.
ones entering t e
air lane and exc ange of s ecific instructions for call
y Establis ment of a reliable communication link across
diverse networks,t e cellular network( SM),t e ST and t e in flig t luetoot etwork
y Tra sfer of Voice Data across this composite comm channel
ication
y A thentication to provi e sec rity and prevent mis se
OperationDetect & connect
Authentication GSM commands
On airplane
System SpecificationBT COMVOICE I/F
BT COMPhone Network
BT
Air to Gnd Com
GSM I/F
CallerAir To Ground Link
MU
GSM
GSM
Ground to Air com PSTN
PSTN i/fLaptop with GSM modem
GSC
Syst m Hard arMOBILE UNITy Emulates Bluetooth enabled handset y Consists of a laptop connected to mobile telephony through a
serial port and to the BT kit through USBy Mobile telephony consist of a GSM modem with its antenna and
a Subscriber Identity Module (SIM)
Mo il
nitAntenna Audio
USB
RS 232
Sim
In Flight BTAGy Th unit consist of a
connected to the BT kit through
SBy It take care of routing voice data to the a
ro riate
mo ile hone through the corres onding BT ort.y The BTAG is connected to the GS over the air-to-ground
link.
Ground Switching CentrePC
Bluetooth To PSTN RS 232USBPhone Modem
GSCy Consists of a PC connected to a phone modem. y A bluetooth module is connected to the PC through USB y The phone modem is connected to the Public Switch
Telephone Network (PSTN)
Software ModulesBluetooth Moduley Main program by which other modules are invoked y Functionsy Automatic connection establishment & maintenance y Sequential invoking of various modules y Voice transfer over ACL bluetooth link
y BT module continuously scans the environment y BT devices receives the BTAG inquiry msg and reply to it y BTAG learns the address of every device and assigns a port to
connecty Bluetooth module comprises of the authentication tool
GSM Moduley Invoked by BlueTooth module y Initializes the communication with GSM modem
through serial port
PSTN ModuleFeaturesy Accepting call from landline caller and establishing a
connection on the PSTNy Signaling to the BTAG to indicate call arrival y Streaming voice obtained from the BTAG over the PSTN
connection and viceversay Directing a call from MU to a phone number on ground
Toolsy Three key tools for handling various software and
hardware components arey Authentication Tool y Voice Tool
Authentication ToolFunctionsy Enable the mobile to check the BTAG is a genuine device y Enable the BTAG to determine that the mobile handset
belongs to the passenger in flighty Allot a call forwarding number to the mobile handset
BTAG Generic Key sent from BTAG Mobile sends its phone number GSM redirection command GSM shutdown
Mobile Unit
Voice Tooly Provide facilities for recording and playout of voice y Used by bluetooth module at both BTAG-GSC and Mobile Unit y Consists of a recorder and a player
Voice Tool Flow DiagramInitialise mic & spkr Obtain device handle from PSTN module
Get data from mic
Get data from BT module
Get data from PSTN
Get data from BT module
Give data to BT module
Playout on spkr
Give data to BT module
Give data to PSTN module
Advantagesy Provide seamless connectivity to cellular network while inside
the Airplanesy It uses Bluetooth technology having fast frequency hopping
which presents negligible interface ATC signalsy No need to change the handset y No need to change the SIM service
Conclusiony The Sky mobile system integrates different communication
networks to provide the user seamless connectivity on their usual mobile while travelling by air.
y Still it is a prototype and we can hope that this systems will be
soon introduced successfully in the market
REFERENCESy Connexion:www.mobilecomms-technology.com/projects/connexion/ y Global star, Qualcomm alliance: in-flight broadband access: y y y y y y y
www.qualcomm.com/globalstar/bp/news/ Wave COM WM0D2, GSM modem specification: www.wavecom.com/showroom/specification/wm0d2.html Bluetooth Core and Profiles specifications, v1.0b http://www.bluetooth.com/developer/specification/specification.asp Microsoft Developer Network, www.msdn.microsoft.com Bluetooth PC Reference Stack by Ericcson: User s Manual. WM2A GSM Module Specifications driven by AT commands: WISMO documentation.
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