Tracking and Positioning of Mobile Systems in Telecom Network

7/22/2019 Tracking and Positioning of Mobile Systems in Telecom Network

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Tracking And Positioning Of Mobile Systems

In Telecommunication Networks


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Emergency service for subscriber safety.

Location sensitive billing.

Cellular Fraud detection.

Intelligent transport system services.

Efficient and effective network performance

and management.

NEED FOR TRACKING


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Configuration of a typical mobile telecommunication network.


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Whole service area is divided into several coverage areas known as a cell.Eacharea has a separate base station!"#$.

Every "# is provided with a fre%uency of range &'( to )(( *+,.

-he *-# controls the "#s so that the subscriber can continue his call without

interruption.

-racking the location within the boundary of a cell in a telecommunication network is

known as location based services. *obile -echnology includes mainly two functions namely call fi/ing and hands off

process.

Call fi/ing is process of connecting a call.

+ands off is changing the "# fre%uency of the user.

INTO!"CTION TO MO#I$% T%C&NO$O'(


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0 geolocation service provider provides

location information and location aware

sevices to subscribers.

-he service provider will contact the

location control center about the coordinates

of the mobile system !*#$.

-he location control center will gather

information re%uired to compute the *#1slocation.

-he service provider will then use this

information to visually display the *#1s

location to the subscriber.

-he subscriber can be the *# itself.

AC&IT%CT"% O) A '%O$OCATION S(ST%M

2ELC0-I3 #4#-E*

05C+I-EC-65E 78(#((9


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PSAP trying to answer an %*+,, call


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:.+03;#E- "0#E; *"ILE 0L *E-+;

?.;I#-03CE "0#E; 0L!-0$

?.= -I*E ;IFFE5E3CE F 055I>0L!-;0$

&. LC0-I3 -50C8I32 C65>E *E-+;

T%C&NO$O'I%S "S%! )O '%O$OCATION


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'$O#$% POSITIONIN' S(ST%M -'PS

-o locate the mobile telephone by

itself@ the mobile telephone is provided

with a 2


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-he navigational signals transmitted by 2


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#ince all of the satellite signals are modulated onto the same L: carrier fre%uency@there is a need to separate the signals after demodulation. ;emodulating and

;ecoding of 2


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6sing messages received from a minimum of four visible satellites@ a 2


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APP$ICATIONS O) 'PS


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AN'$% O) AI/A$ M%T&O!

-his method calculates the angle of arrival of

signal receiving at the "#. When a mobile user switches the system 3

it receives the signal from different base

stations@ may be ? or & or more. -he angle of

arrival method re%uires two or more base

station for the determination. It measures the direction of signal falling on

the base station and measures the angle of

incidence with respect to a normal and

determines the position of the system. 0ngle of arrival method is not an accurate

method used for the mobile positioning

because of its some disadvantages such asatmospheric particles@ scattering etc.


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;I#-03CE "0#E;


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;I#-03CE "0#E;


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$OCATION TAC0IN' C"/% M%T&O!


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-he location data processor draws two circles C: and C= with their respective

centers set at "#s -: and -= based on the -0s of a signal transmitted from

the corresponding mobile telephone *: or *= to the two "#s -: and -=

located near the mobile telephone *: or *=. -he two circles C: and C= define

a common chord L:.

-herefore@ we use location tracking curves -5: and -5= connecting the same

two intersection points


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!etermination of t1e location tracking cur2e

0ssuming that the first and the second "#s

-: and -= selected for use in the location

tracking are present at positions !/:@ y:$ and

!/=@ y=$@ respectively@ the location data

processor draws the two circles C: and C=

with the coordinates !/:@ y:$ and !/=@ y=$ of

the two "#s -: and -= at their centers -he curve connects the two points


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-he variances of the -0s of a signal which arrives at the two "#s -: and -= fromdifferent paths are used to find the curve on which the actual location of the mobile

telephone is determined.

-he location data processor compares the variances calculated by the first "# -:

with the variances calculated by the second "# -= and considers that the mobile

telephone is near to that "# with the larger variances and selects the "# with smaller

variances as a reference point to draw the reference circle. -he location data processor compares the variances calculated by the two "#s -:

and -= and selects the base station with smaller variances as a reference point to

draw the refer

If the selected variances !those of the second "# -=$ are K@ the location data

processor compares the selected variances K@ with the preset reference variances K

:@ K =@ and K ?.

-he location data processor selects the optimal curve !reference circle$ for the two

"#s among the several "#s@ and selects another optimal circle for another "# pair@

and so on.

eference circle selection


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)INA$ POSITIONIN' O) MO#I$%

When curves are selected for all

selected "# pairs@ the location data

processor obtains the intersection

points among the selected curves. 0s the selected curves do not intersect

at one point due to the multiApath fading

or the 3L# effects@ the midpoint of

these intersection points is determined

as the location of the mobile telephone. -he location data processor represents

the intersection points in the latitude

and the longitude coordinates andtransmits the position coordinates to the

network and the mobile telephone.


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ur proposal is advantageous in that the location of a mobile telephone can beaccurately tracked even in the multiApath fading and the 3L# environment@ by

using more accurate tracking curves connecting the intersection points among

circles.

We have described about accurate positioning of mobile telephones@ which can

be used for several applications.

-he important considerations to be undertaken while selecting a location based

technology are location accuracy@ implementation cost@ reliability@ increasing

functionality.

S"MMA(


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T&AN0 (O"

Tracking and Positioning of Mobile Systems in Telecom Network

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