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.

Queries?