tejashwini s.g main-presentation

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TRACKING AND POSITIONING

OF MOBILES IN

TELECOMMUNICATION

Tejashwini .S.G

3VC07IS052



OVREVIEW OF THE TOPICS:

1. DEFINATIONS

2. REVIEW TO MOBILE TECHNOLOGY3. NEED FOR TRACKING

4. ARCHITECTURE OF A GEOLOCATION SYSTEM

5. TECHNOLOGIES USED FOR GEOLOCATION

GPS BASED CELLPHONE TRACKING

GSM BASED CELLPHONE TRACKING

HYBRID DIRECTION BASED GEOLOCATION

6. DISTANCE BASED POSITIONING:

TIME OF ARRIVAL(TOA)

TIME DIFFERENCE OF ARRIVAL (TDOA)

LOCATION TRACKING CURVE METHOD

7. APPLICATIONS ENHANCED 911

LOCATION BASED SERVICES AND AREA OF USE

CELLULAR FRAUD DETECTION

8. CONCLUSION



DEFINATIONS:

A mobile phone (also called mobile, cellular phone, cell phone or hand phone)is an electr onic device used f or full duplex two-way radio

telecommunications over a cellular network of base stations known as cell

sites.



BASE STATION : Base stations use radio signals to connect mobile phones

to the network, ena bling peo ple to send and receive calls, texts, emails,

pictures, we b, TV and downloads. Without base stations, mobile phoneswill not work. Base stations are connected to each other by ca bles or

wireless technology such as micr owave dishes, to create a network.



MTSO: Mobile Telephone Switching Office

The MTSO is

the swi

tching

offi

ce

tha

t co

nnect

s allo

f the individual

cell

towers

to the Central Office (CO).

The MTSO is responsi ble f or monitoring the relative signal strength of your

cellular phone as repor ted by each of the cell towers.

The MTSO is als

o

respo

nsi b

le f o

r switc

hing yo

ur co

nversat

io

nto

t

hec

ellto

wer which will give you the best possi ble reception.



BASE STATION CONTROLLER

� The base station contr oller (BSC) pr ovides, classically, the intelligence

behind the BTSs.

� Typically a BSC has tens or even hundreds of BTSs under its contr ol.



ESN AND MIN: An electr onic serial number (ESN) is the unique

identification number embedded or inscri bed on the micr ochip in awireless phone by the manufacturer.

� Each time a call is placed, the ESN is automatically transmitted to

the base station so the wireless carrier's mobile switching office cancheck the call's validity.

� The ESN cannot easily be altered in the field. The ESN differs fr om

the mobile identification number (MIN), which is the wirelesscarrier's identifier f or a p hone in the network.

� MINs and ESNs can be electr onically checked to help prevent fraud.

Public Safety Answering Point (PSAP): The final destination of anE911 call (where the 911 o perator sits) is a Pu blic Safety AnsweringPoint (PSAP).



R EVIEW TO MOBILE TECHNOLOGY

Mobile positioning technology has become an im por tant area of resear ch, f or

emergency as well as f or commer cial services.

Mobile positioning in cellular networks will pr ovide several services such as,

locating stolen mobiles, emergency calls, different billing tariffs depending on

where the call is originated, and methods to predict the user movement insidea region.

The major challenge to accurate location estimation is in creating techniques

that yield accepta ble perf or mance when the direct path fr om the transmitter to

the receiver is inter mittently blocked. This is the Non-Line-Of -Sight (NLOS)

pr ob

lem

, and it

is known

to be a

maj

or s

our

ce

of err

or sin

ce i

tsys

te

ma

tically

causes mobile to appear far ther away fr om the base station (BS) than it

actually is, there by increasing the positioning err or.



MOBILE TELECOMMUNICATION

NETWORKThe mobile telecommunication network

includes a several base stations (BSs) T1 to

T N.

It pr ovides mobile telecommunicationservice to a mobile su bscri ber thr ough a

mobile telephone M1, a base station

contr oller (BSC) f or contr olling the BS s T 1

to T N, and a mobile telephone switching

office (MTSO) f or connecting the BSC to

another BTS or a PSTN (Pu blic SwitchedTelephone Network).



Each BS is pr ovided with a frequency of a range between 450 to900

MHz

More than one cells can use same frequency.

Only condition is that no two adjacent cells must have same frequencies.

MTSO contr ols these BSs so that a su bscri ber can continue his callwithout interruption while moving between different cells.



NEED FOR TR ACKING

1. All the BSs are sending a signal of power 25 to 30w to the mobile unit.

When a user switches ON his mobile, it will sear ch f or the str ongest signal

and got connected to that BS. Then the mobile unit sends an identification

signal to the BS. When he fixes a call, the BS accepts the request and sends

the request to the BSC and MTSO. Then the MTSO will sear ches wherethe su bscri ber is and connects the call.

2. When a user moves to another cell the MTSO will change the frequency

allotted to it and allots the frequency of the new BS. For both these

pr ocesses GEOLOCATION of the mobile unit is essential.

3.R

ecen

tde

mands fr

omnew appli

ca

tions require p

osi

tioning

capa

bili

ties

of mobile telephones or other devices. The a bility to obtain the geo-location

of the Mobile Telephone (MT) in the cellular system allows the network

o perators to facilitate new services to the mobile users.



4. Themo

st

imm

ediat

emot

ivat

io

n f o

r t

hec

ellular syst

em to

pr o

videMT position is enhanced in accident emergency services. The geo-

location of the mobile user could pr ovide services like :

Emergency service f or su bscri ber safety.

Location sensitive billing.

Cellular Fraud detection.

Intelligent transpor t system services.

Efficient and effective network perf or mance and management.



AR CHITECTUR E OF A GEOLOCATION SYSTEM

A geo-location service pr ovider pr ovides location inf or mation and location aware

servic

esto

su b

sc

ri b

ers.

The location contr ol center will gather inf or mation required to com pute the MS¶s location.

This gathered inf or mation could be parameters such as received signal strength, BTS ID, TOA of

signals. These are sometimes called Geolocation base stations (GBSs).

The service pr ovider will then use this inf or mation to visually display the MS¶s location to the

su b

scri

ber.



TECHNOLOGIES USED FOR GEOLOCATION:

HA NDSET BASED

NETWOR K BASED

HYBR ID

SIM BASED

DIR ECTION BASED GEOLOCATION



HA NDSET BASED

� It requires installation of Client Sof tware on the handset to deter mine its location.� This technique deter mines the location of the handset by com puting its location by

cell identification, signal strengths of the home and neigh boring cells, which iscontinuously sent to the carrier.

� In addition, if the handset is also equipped with GPS then significantly more preciselocation inf or mation is then sent fr om the handset to the carrier.

ADVA NTAGES:� It accurately deter mines the position.

DISADVA NTAGES:

� The key disadvantage of this technique (fr om mobile o perator's point of view) is thenecessity of installing sof tware on the handset .

� Increases the price and the size of the mobile telephone.� The load on the mobile telephone is increased.

� Power consum ption is high.



NETWORK BASED:

GSM cell phones' technology works based on small, equal, and adjacent areas. Each area is ter med a "cell". An entire region covered by a service pr ovider contains several such cells.

Network -based techniques utilize the service pr ovider's network infrastructure to identify the location of the handset

The accuracy of network -based techniques varies, with cell identificationas the least accurate and triangulation as the most accurate.

The accuracy of network -based techniques is closely dependent on theconcentration of base station cells, with ur ban envir onments achievingthe highest possi ble accuracy.

ADVA NTAGES:

The advantage of network -based techniques (fr om mobile o perator's point of view) is that

they can be im plemented non-intrusively, without affecting the handsets.

As the installation of hardware and sof tware is within the o perator's infrastructure the

price of the handset is reduced.



Hy

brid p

osi

tioning sys

te

ms are sys

te

ms f

or finding

the l

oca

tio

no

f amob

iledevice using several different positioning technologies. Usually GPS (Global

Positioning System) is one major com ponent of such systems, combined with cell

tower signals, wireless internet signals, Bluetooth sensors or other local

Positioning Systems.

These systems are specifically designed to over come the limitations of GPS,

which is very exa

ctin

o pen areas,

bu

tw

orks p

oorly ind

oors

or

be

tween

tall

buildings

Skyhook¶s Core Engine is a sof tware-only location system that quickly

deter mines device location with 10 to 20 meter accuracy. It is presently

im plemented in USA .

SIM BASED :

Using SIM in GSM and UMTS (Universal Mobile Telecommunication

System)handsets, it is possi ble to obtain raw radio measurements fr om the

handset.

Measurements can include serving Cell-ID, r ound-trip time and signal strength.

Type 0f inf or mation obtained via SIM can differ fr om what is availa ble fr om thehandset.

HYBR ID :



DIR ECTION BASED GEOLOCATION

I. A NGLE OF ARR IVAL METHOD :

In this there will be transmission and reception of

signals between the mobile unit and BSs. This

method calculates the angle of arrival of signal

receiving at the BS.

The angle of arrival method requires two or more

base station f or the deter mination. It measures the

direction of signal falling on the base station and

measures the angle of incidence with respect to a

nor mal and deter mines the position of the system. DISADVA NTAGES

The deter mination of the system will be in err or if the angle of incidence is changed due to anyobstacle like atmospheric par ticles or due to scattering etc.

The accurate location cannot be deter mined if the mobile user is in between the BSs, that is in

a straight line.

It cannot be used f or the indoor envir onments.

The direction based mobile positioning is not used commonly now a day. It is replaced by the

distan

ce

based

mobile p

osi

tio

ningte

chn

olo

gies.



DISTANCE BASED POSITIONING

TIME OF ARR IVAL (TOA):

The TOA method calculates the distance of a mobile telephone and a BS based on

the TOA of a signal transmitted fr om the mobile telephone at the BS.

It is assumed that the mobile telephone is located at the intersection point of three

cir cles having the radius of the distances between the BSs and the mobile

telephone.



.

�Three cir cles C1, C2, and C3, whose radii are the distance between the mobile telephone

M1 and at least three BSs T1, T2, and T3, are overlapped acr oss an area. The mobile

telephone M1 is located in the overlap area.

�When at least three cir cles C1, C2, and C3 are overlapped over an area without meeting

at one point, the mobile telephone M1 is considered to exist at the intersection point of

three common chords L1, L2, and L3.

The a bove method using the common chord is not very accurate in locating the mobile

telephone except in the case where the mobile telephone is at an appr oximate equal

distance fr om the selected BSs and in a similar pr o pagation envir onment to each

respective BS



� Two cir cles C11 and C21 are drawn based on the

TOAs of a signal transmitted fr om the first mobiletelephone M1 at the first and the second BSs T1 and

T2.

� A first common chord L1 is defined by the

intersection between the cir cles C11 and C21.

� But if the path between the first mobile telephone

M1 andthe se

cond

B

S T2 is in an NLOSco

nditionand the path between the first mobile telephone M1

and the first BS T1 is in a line-of sight (LOS)

condition, the common chord L1 is positioned far

lef t fr om the actual location of the mobile telephone

M1.

The TDOA method assumes that the TDOAs of a signal transmitted from the mobile telephone at the

three BSs define a set of points on a hyperbola, and

the mobile telephone is located at the intersection

point of at least three hyperbolas .

TIME DIFFERENCE OF ARRIVAL(TDOA)



When a location service is requested a bout

a specific mobile telephone by a user or a

network, the location data pr ocessor drawstwo cir cles C1 and C2 with their

respective centers set at BSs T1 and T2

based on the TOAs of a signal transmitted

fr om the corresponding mobile telephone

M1 or M2 to the two BSs T1 and T2

located near the mobile telephone M1 or M2. The two cir cles C1 and C2 define a

common chord L1.

LOCATION TRACKING CURVE METHOD :

As the a bove method doesn't find the actual

position when phone is in NLOS .This methodis used.



� location tracking curves TR 1 and TR 2 connecting the same two intersection points P1

and P2 of the two cir cles C1 and C2, instead of the common chord L1.

� The two curves TR 1 and TR 2 have their middle points intersecting the line ST, which

connects the positions of the two BSs T1 and T2 and the par ts of two cir cles C1 and

C2 drawn to connect the two intersection points P1 and P2.

� Instead of the common chord L1, the location data pr ocessor uses the curve TR 1 f or

the mobile telephone M1 and the curve TR 2 f or the mobile telephone M2. It prevents

the location err or caused by the multi- path fading or the NLOS path characteristics.



APPLICATIONS:

1. Em

ergenc

y servic

e f o

r su b

sc

ri b

er safet

y.2. Location based services.

3. Cellular Fraud detection.

4. Intelligent transpor t system services.

ENHANCED 911:

In America, call 911 when there's an emergency. When 911is dialed , the -call is

automatically f orwarded to a pu blic-safety answering point (PSAP), also called a

911 call center. Today, many areas also have Enhanced 911 (E-911), which allows a

PSAP to deter mine the general location fr om where the call originated, but cannot

yet pinpoint the location.



� Location inf or mation must be accurate within 164 to 984 feet (50-300 meters). a cell-

phone user's phone number, or Automatic Number Identification (A NI), and the address

and location of the receiving-antenna site will be sent to the E-911 Tandem, the switch

that r outes 911 calls to the appr o priate PSAP based on the A NI-defined geographic

location.

�Once the caller's voice and A NI are transferred to the PSAP, the PSAP o perator will be

a ble to view a graphic display that shows the longitude and latitude of the person as

accessed thr ough GPS satellites.

�The o perator's com puter will link to the ALI data base, which stores address data andother inf or mation.

�The caller's address and inf or mation is displayed to the call taker immediately upon call

arrival.

�This pr ovides e

mergen

cy resp

onders wi

th

the l

oca

tio

no

f the e

mergen

cy wi

th

ou

t the person calling f or help having to pr ovide it.

�This is of ten useful in times of fires, break -ins, kidnapping, and other events where

communicating one's location is difficult or im possi ble.

� The final phase requires carriers to place GPS receivers in phones in order to deliver

more specific latitude and longitude location inf or mation.



LOCATION BASED SER VICES:

A location-based service (LBS) is an inf or mation and enter tainment service,

accessi ble with mobile devices thr ough the mobile network and utilizing the a bility

to make use of the geographical position of the mobile device .Some exam ples of location-based services are:

� R equesting the nearest business or service, such as an ATM or restaurant

� Turn by turn navigation to any address

� Locating peo ple on a map displayed on the mobile phone

� R eceiving aler ts, such as notification of a sale on gas or warning of a traffic jam� Location-based mobile adver tising.

REAL TIME APPLICATIONS

GOOGLE LATITUDE



Google Latitude a feature intr oduced on Google Maps in 2009 that can be accessed on

both mobile phones and PCs, f or exam ple. It lets you share your location and see

where your friends and family are on a digital map.

In India, two o perators Bhar ti and Hutch(presently Vodaf one)have intr oduced location-

based services of different kinds.

Hutch¶s location-based service launched in Delhi and NCR is called 'Hutch4help'.

Hutch has offered this service to all its su bscri bers including the prepaid and the

post- paid card holders owning any brand of handset and SIM card memory of any

level. Hutch service is a dial-in location based service. Hutch pr ovides police,chemist, hospital and taxi service on Hutch4help.

Bhar ti gr oup calls its location based services as 'Ar ound-me' which is o perational in

Mumbai and Delhi.

Air tel service is data (SMS) based. Bhar ti offers services like sho pping (clothes,

electr onics, gif ts, interior etc.) with discounts, restaurant, enter tainment (discos,

pu bs etc.), utilities(taxis, banks, ATMs, travel agents, car servicing centres ,

petr ol pum p, car dealers), medical (chemists, hospitals and doctors) and hotels (5/3

star, budget). The user has to press clothes in the sho pping menu while person is

ar ound a cer tain area and he gets an SMS with details of sho p names, addresses,

and phone numbers within 10 k m radius.



REFERENCES

J. Caffery , and G. Stu ber Jr, ³Vehicle location and tracking f or

IVHS in CDMA micr o-cells´, Pr oc. IEEE P IMRC , 1994

G. Morley, and W. Gr over, ³Im pr oved location estimation with

pulse-ranging in presence of shadowing and multi- path

excess-delay effects´, Electr onics Letters, vol.31, No.18, 1995

www.ieeexpl

ore.ieee.

org

gp.espacenet.com



CONCLUSION

Hence it can be concluded that the tracking and deter mining the position

of mobile phone accurately is im por tant even in the multi- path fading

and the NLOS envir onment.

Accurate positioning of mobile telephones, which can be used f or

several applications.

Theimportant consid

erations to b

eund

ertak

en w

hile

selecting a location bas

edtechnology ar e location accuracy, implementation cost, r eliability, incr easing functionality.



THANK YOU...!!



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